Condition of having pores or open spaces. This often refers to bones, bone implants, or bone cements, but can refer to the porous state of any solid substance.
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
A flammable, poisonous gas with a characteristic odor of rotten eggs. It is used in the manufacture of chemicals, in metallurgy, and as an analytical reagent. (From Merck Index, 11th ed)
A circular structural unit of bone tissue. It consists of a central hole, the Haversian canal through which blood vessels run, surrounded by concentric rings, called lamellae.
The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.
The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
Cell growth support structures composed of BIOCOMPATIBLE MATERIALS. They are specially designed solid support matrices for cell attachment in TISSUE ENGINEERING and GUIDED TISSUE REGENERATION uses.
Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.
Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.
Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.
Material from which the casting mold is made in the fabrication of gold or cobalt-chromium castings. (Boucher's Clinical Dental Terminology, 4th ed, p168)
Production of a radiographic image of a small or very thin object on fine-grained photographic film under conditions which permit subsequent microscopic examination or enlargement of the radiograph at linear magnifications of up to several hundred and with a resolution approaching the resolving power of the photographic emulsion (about 1000 lines per millimeter).
Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.
Substances made up of an aggregation of small particles, as that obtained by grinding or trituration of a solid drug. In pharmacy it is a form in which substances are administered. (From Dorland, 28th ed)
Characteristics or attributes of the outer boundaries of objects, including molecules.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Hydrogen cyanide (HCN); A toxic liquid or colorless gas. It is found in the smoke of various tobacco products and released by combustion of nitrogen-containing organic materials.
X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.
Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.
A biocompatible polymer used as a surgical suture material.
Artificial substitutes for body parts and materials inserted into organisms during experimental studies.
The species Balaena mysticetus, in the family Balaenidae, found in the colder waters of the Northern Hemisphere. The common name is derived from the extreme arching of the lower jaw.
The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).
The longest and largest bone of the skeleton, it is situated between the hip and the knee.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.
Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.
Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
Adhesives used to fix prosthetic devices to bones and to cement bone to bone in difficult fractures. Synthetic resins are commonly used as cements. A mixture of monocalcium phosphate, monohydrate, alpha-tricalcium phosphate, and calcium carbonate with a sodium phosphate solution is also a useful bone paste.
Relating to the size of solids.
Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)
A group of thermoplastic or thermosetting polymers containing polyisocyanate. They are used as ELASTOMERS, as coatings, as fibers and as foams.
Physical reactions involved in the formation of or changes in the structure of atoms and molecules and their interactions.
Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).
An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.
The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)
The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.
A plant genus of the family OLEACEAE. Members contain secoiridoid glucosides.
Nanometer-scale composite structures composed of organic molecules intimately incorporated with inorganic molecules. (Glossary of Biotechnology and Nanobiotechology Terms, 4th ed)
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A group of phosphate minerals that includes ten mineral species and has the general formula X5(YO4)3Z, where X is usually calcium or lead, Y is phosphorus or arsenic, and Z is chlorine, fluorine, or OH-. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
A research technique to measure solvent exposed regions of molecules that is used to provide insight about PROTEIN CONFORMATION.
Submicron-sized fibers with diameters typically between 50 and 500 nanometers. The very small dimension of these fibers can generate a high surface area to volume ratio, which makes them potential candidates for various biomedical and other applications.
Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Materials which have structured components with at least one dimension in the range of 1 to 100 nanometers. These include NANOCOMPOSITES; NANOPARTICLES; NANOTUBES; and NANOWIRES.
The shaft of long bones.
Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.
The preparation, mixing, and assembling of a drug. (From Remington, The Science and Practice of Pharmacy, 19th ed, p1814)
The family of carnivorous or omnivorous bears, having massive bodies, coarse heavy fur, relatively short limbs, and almost rudimentary tails.
The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)
A polymer prepared from polyvinyl acetates by replacement of the acetate groups with hydroxyl groups. It is used as a pharmaceutic aid and ophthalmic lubricant as well as in the manufacture of surface coatings artificial sponges, cosmetics, and other products.
Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.
Process by which unwanted microbial, plant or animal materials or organisms accumulate on man-made surfaces.
Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Water swollen, rigid, 3-dimensional network of cross-linked, hydrophilic macromolecules, 20-95% water. They are used in paints, printing inks, foodstuffs, pharmaceuticals, and cosmetics. (Grant & Hackh's Chemical Dictionary, 5th ed)
A multifunctional pyridoxal phosphate enzyme. In the final step in the biosynthesis of cysteine it catalyzes the cleavage of cystathionine to yield cysteine, ammonia, and 2-ketobutyrate. EC 4.4.1.1.
A plant genus of the family FABACEAE.
The rate dynamics in chemical or physical systems.
The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.
A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)
The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Numerical expression indicating the measure of stiffness in a material. It is defined by the ratio of stress in a unit area of substance to the resulting deformation (strain). This allows the behavior of a material under load (such as bone) to be calculated.
A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.
The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.
The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The joining of objects by means of a cement (e.g., in fracture fixation, such as in hip arthroplasty for joining of the acetabular component to the femoral component). In dentistry, it is used for the process of attaching parts of a tooth or restorative material to a natural tooth or for the attaching of orthodontic bands to teeth by means of an adhesive.
A cellulose derivative which is a beta-(1,4)-D-glucopyranose polymer. It is used as a bulk laxative and as an emulsifier and thickener in cosmetics and pharmaceuticals and as a stabilizer for reagents.
A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Mature osteoblasts that have become embedded in the BONE MATRIX. They occupy a small cavity, called lacuna, in the matrix and are connected to adjacent osteocytes via protoplasmic projections called canaliculi.
Salts and esters of the 10-carbon monocarboxylic acid-decanoic acid.
The growth action of bone tissue as it assimilates surgically implanted devices or prostheses to be used as either replacement parts (e.g., hip) or as anchors (e.g., endosseous dental implants).
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.
The buckthorn plant family, of the order Rhamnales, includes some species with edible fruits and some that are medicinal.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Magnesium oxide (MgO). An inorganic compound that occurs in nature as the mineral periclase. In aqueous media combines quickly with water to form magnesium hydroxide. It is used as an antacid and mild laxative and has many nonmedicinal uses.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
An enzyme found in bacteria. It catalyzes the reduction of FERREDOXIN and other substances in the presence of molecular hydrogen and is involved in the electron transport of bacterial photosynthesis.
Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.
Usually inert substances added to a prescription in order to provide suitable consistency to the dosage form. These include binders, matrix, base or diluent in pills, tablets, creams, salves, etc.
A space in which the pressure is far below atmospheric pressure so that the remaining gases do not affect processes being carried on in the space.
Polyester polymers formed from terephthalic acid or its esters and ethylene glycol. They can be formed into tapes, films or pulled into fibers that are pressed into meshes or woven into fabrics.
The process of bone formation. Histogenesis of bone including ossification.
A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.
The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.
A plant family of the order Violales, subclass Dilleniidae, class Magnoliopsida. Bixa contains bixin. Cochlospermum contains arjunolic acid and gum kondagogu (POLYSACCHARIDES).
The quality or state of being wettable or the degree to which something can be wet. This is also the ability of any solid surface to be wetted when in contact with a liquid whose surface tension is reduced so that the liquid spreads over the surface of the solid.
A polyester used for absorbable sutures & surgical mesh, especially in ophthalmic surgery. 2-Hydroxy-propanoic acid polymer with polymerized hydroxyacetic acid, which forms 3,6-dimethyl-1,4-dioxane-dione polymer with 1,4-dioxane-2,5-dione copolymer of molecular weight about 80,000 daltons.
Resistance and recovery from distortion of shape.
The process of producing a form or impression made of metal or plaster using a mold.
A network of cross-linked hydrophilic macromolecules used in biomedical applications.
Tantalum. A rare metallic element, atomic number 73, atomic weight 180.948, symbol Ta. It is a noncorrosive and malleable metal that has been used for plates or disks to replace cranial defects, for wire sutures, and for making prosthetic devices. (Dorland, 28th ed)
Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.
The dormant state in which some warm-blooded animal species pass the winter. It is characterized by narcosis and by sharp reduction in body temperature and metabolic activity and by a depression of vital signs.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Computer-assisted study of methods for obtaining useful quantitative solutions to problems that have been expressed mathematically.
A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086].
Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Polymerized methyl methacrylate monomers which are used as sheets, moulding, extrusion powders, surface coating resins, emulsion polymers, fibers, inks, and films (From International Labor Organization, 1983). This material is also used in tooth implants, bone cements, and hard corneal contact lenses.
Implants constructed of materials designed to be absorbed by the body without producing an immune response. They are usually composed of plastics and are frequently used in orthopedics and orthodontics.
A polyvinyl polymer of variable molecular weight; used as suspending and dispersing agent and vehicle for pharmaceuticals; also used as blood volume expander.
The largest of three bones that make up each half of the pelvic girdle.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.
The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.
Dosage forms of a drug that act over a period of time by controlled-release processes or technology.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Materials fabricated by BIOMIMETICS techniques, i.e., based on natural processes found in biological systems.
Tablets coated with material that delays release of the medication until after they leave the stomach. (Dorland, 28th ed)
Computer-based representation of physical systems and phenomena such as chemical processes.
The behaviors of materials under force.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.
Procedures for enhancing and directing tissue repair and renewal processes, such as BONE REGENERATION; NERVE REGENERATION; etc. They involve surgically implanting growth conducive tracks or conduits (TISSUE SCAFFOLDING) at the damaged site to stimulate and control the location of cell repopulation. The tracks or conduits are made from synthetic and/or natural materials and may include support cells and induction factors for CELL GROWTH PROCESSES; or CELL MIGRATION.
Elements of limited time intervals, contributing to particular results or situations.
A product formed from skin, white connective tissue, or bone COLLAGEN. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories.
The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
The degassing step reduces the occurrence of hydrogen gas porosity. In the steel making process, this method is used very ... The argon bubbles rise to the surface, bringing with them some of the dissolved hydrogen. ...
Porosity often seriously deteriorates the mechanical properties of the metal. An efficient way of removing hydrogen from the ... Alternatively, the presence of hydrogen can be measured by determining the density of a metal sample. In cases where porosity ... If the hydrogen concentration in the melt is too high, the resulting casting will be porous; the hydrogen will exit the molten ... Hydrogen is a common contaminant for most cast metals. It forms as a result of material reactions or from water vapor or ...
... and cause hydrogen embrittlement. The hydrogen present in the flame or atmosphere at high temperature reacts with the oxide, ... The steam bubbles exert high pressure in the metal structure, leading to cracks and joint porosity. Oxygen-free copper is not ... Noble gas+hydrogen (AWS type 9A). *Vacuum: Requires evacuating the work chamber. Expensive. Unsuitable (or requires special ... Nitrogen+hydrogen+carbon monoxide, cryogenic or purified (AWS type 6B): 70-99% N2, 2-20% H2, 1-10% CO. For copper, silver, ...
Nitrogen, oxygen and hydrogen are the most encountered gases in cases of gas porosity. In aluminium castings, hydrogen is the ... Hydrogen gas porosity Inclusions in aluminium alloys Non-metallic inclusions for inclusions in steel Porosity sealing Rao 1999 ... Gas porosity may present itself on the surface of the casting as porosity or the pore may be trapped inside the metal, which ... Drying the mould can eliminate this source of hydrogen formation. Gas porosity can sometimes be difficult to distinguish from ...
Hence, the porosity of porous silicon is varied depending on its potential application areas. The porosity value of silicon is ... the hydrogen bubbles stick to the surface and induce lateral and in-depth inhomogeneity The hydrogen evolution is normally ... its surface is covered with covalently bonded hydrogen. Although the hydrogen coated surface is sufficiently stable when ... The porosity of porous silicon may range from 4% for macroporous layers to 95% for mesoporous layers. A study by Canham in 1995 ...
A mechanochemical approach to carbons with superior porosity and exceptional performance for hydrogen and CO2 storage". Nano ... Yang, Zhuxian; Xia, Yongde; Mokaya, Robert (2007-02-01). "Enhanced Hydrogen Storage Capacity of High Surface Area Zeolite-like ... He investigates novel materials for carbon sequestration, focussing primarily on hydrogen fuel cells. Mokaya considers porous ...
"Combining High Porosity with High Surface Area in Flexible Interconnected Nanowire Meshes for Hydrogen Generation and Beyond". ... Such method gives nanofoams with an organized structure and allows to control the surface area and porosity of the fabricated ...
To aid curing, hydrogen peroxide is added. Compaction by vibrocompression vacuum process uses elastomeric molds in which a ... The vibration helps compact the mixture and results in an isotropic slab with virtually no porosity. Engineered stone is then ...
The oil is a light oil with 45 API gravity with a high gas-oil ratio and hydrogen sulphide (H2S) content of 19%. The field is ... The reservoir consists of limestones with low porosities and permeabilities. ... When the pipeline was shutdown, Hydrogen Sulfide remaining in the pipe was burned off as an emergency measure, releasing Sulfur ... extremely shallow water and high levels of hydrogen sulfide, together with mismanagement and disputes, make it one of the most ...
However, it should not be used on steel, aluminum or magnesium because it can cause porosity and hydrogen embrittlement. ... Hydrogen is sometimes added to argon in small concentrations (up to about 5%) for welding nickel and thick stainless steel ... In GMAW the primary cause of porosity is gas entrapment in the weld pool, which occurs when the metal solidifies before the gas ... Two of the most prevalent quality problems in GMAW are dross and porosity. If not controlled, they can lead to weaker, less ...
Reduces weld porosity in copper. Argon-hydrogen H-2 (98% argon/2% hydrogen) H-5 (95% argon/5% hydrogen) H-10 (80% argon/20% ... Sulfur hexafluoride can be added to shield gas for aluminium welding to bind hydrogen in the weld area to reduce weld porosity ... However, it should not be used on steel, aluminum or magnesium because it can cause porosity and hydrogen embrittlement; its ... It reduces the content of hydrogen in the aluminium weld, preventing the associated porosity. Argon-carbon dioxide C-50 (50% ...
Hydrogen probes are used to monitor the penetration of hydrogen into steels, which can cause brittleness, porosity or ...
This is especially important because of an aluminium weld's susceptibility to porosity due to hydrogen and dross due to oxygen ... The most prominent of these is hydrogen induced cold cracking. The weldability of steel, with regard to hydrogen-induced cold ... For steel there are three major failure modes by which weldability can be measured: hydrogen-induced cold cracking, lamellar ...
However, due to the relatively weak strength of hydrogen bonds, HOFs rarely exhibit permanent porosity upon removal of solvent ... Crystal structures of DPT-MIDA and DPSe-MIDA showed the presence of C-H⋯O hydrogen bonding and C-H⋯π interactions. DPTe-MIDA ... Hydrogen-bonded organic frameworks (HOFs) are porous organic materials that are connected by non-covalent interactions such as ... Treating the tellurophene with hydrogen peroxide (H2O2) resulted in a red-shifted absorption peak at 435 nm in the UV-vis ...
The oxide forms blackened areas called burns on the surface of the casting, and the liberated hydrogen may cause porosity. ...
Especially important are high surface area materials with controlled porosity and nanostructured catalysts. Reactions studied ... ammonia decomposition and catalyzed hydrogen storage. This research is supported by studies into the fundamental processes ...
The neutron porosity log is predominantly sensitive to the quantity of hydrogen atoms in a particular formation, which ... This bulk density can then be used to determine porosity. The neutron porosity log works by bombarding a formation with high ... The difference between neutron porosity and electrical porosity measurements therefore indicates the presence of hydrocarbons ... the porosity measured gives a figure close to the true physical porosity whereas the figure obtained from electrical ...
Synthesis gases derived from these hydrogen-poor feedstocks has a low-hydrogen-content and require the water-gas shift reaction ... Thus a low catalyst porosity with small pore diameters as obtained from fused magnetite (plus promoters) after reduction with ... Natural gas has a high hydrogen to carbon ratio, so the water-gas shift is not needed for cobalt catalysts. Iron catalysts are ... Hydrogen and carbon dioxide react over a cobalt-based catalyst, producing methane. With iron-based catalysts unsaturated short- ...
The open porosity commonly ranges from 15% to 20% and pore water salinity reaches 200 g/l. CO2 storage of this formation has ... Different options of Hydrogen reservoirs underground storage were studied at the Łeba Elevation, Fore-Sudetic Monocline, ... International Journal of Hydrogen Energy, 42(1), 347-355. Marek, S., Dziewinska, L., & Tarkowski, R. (2011). The Geological ... Tarkowski, R. (2017). Perspectives of using the geological subsurface for hydrogen storage in Poland. ...
Porosity and brittleness were the primary problems, and the solutions that developed included the use of hydrogen, argon, and ... Other arc welding processes include atomic hydrogen welding, electroslag welding (ESW), electrogas welding, and stud arc ... Types of welding defects include cracks, distortion, gas inclusions (porosity), non-metallic inclusions, lack of fusion, ...
A solution of hydrogen peroxide produces porous needles - their porosity is controlled along their length by altering the ...
Porosity and brittleness were the primary problems and the solutions that developed included the use of hydrogen, argon, and ... Stick electrodes for such materials, with special low-hydrogen coating, are delivered in sealed moisture-proof packaging. New ... Some materials, notably high-strength steels, aluminium, and titanium alloys, are susceptible to hydrogen embrittlement. If the ... Other arc welding processes include atomic hydrogen welding, carbon arc welding, electroslag welding, electrogas welding, and ...
Singleton P and D Sainsbury (2001). "Hydrogen-oxidizing bacteria (the 'hydrogen bacteria'; knallgas bacteria)". Dictionary of ... sediment porosity, and grain size. These criteria indicate that certain sediment types, such as abyssal clays and siliceous ... and recombine to produce hydrogen peroxide (H2 O2), and molecular hydrogen (H2). The amount of radiolytic H2 production in ... So, despite the known occurrence of radiolytic H2 production, molecular hydrogen is below the detectable limit in the SPG cores ...
In this method, the small bifunctional monomer containing active hydrogen atoms is replaced by a biosourced polymer, like a ... The method is very versatile, and the properties of the microcapsules (size, porosity, degradability, mechanical resistance) ... of this method is the classical Schotten-Baumann reaction between an acid chloride and a compound containing an active hydrogen ...
The two most common properties measured by nuclear tools are formation porosity and rock density: Formation porosity is ... Second, the hydrogen atoms are tipped by a short burst from an oscillating magnetic field that is designed so that they precess ... First, the hydrogen atoms are aligned in the direction of a static magnetic field (B0). This polarization takes a ... In any matrix which has some porosity, the pore spaces will be filled with a fluid of oil, gas (either hydrocarbon or otherwise ...
Non-metallic inclusions for inclusions in steel Hydrogen gas porosity Doutre, D., Gariepy, B., Martin, J.P. and Dube, G., " ... When aluminium solidifies, they form spherical voids similar to hydrogen gas porosity but the void contains a chloride crystal ... A predetermined quantity of liquid aluminum is filtered under controlled conditions using a very fine porosity filter. ... automotive trim and lithographic material Breakage in wire drawing operation Increased tool wear and tear Increased porosity ...
They exhibit permanent porosity with specific surface areas surpassing those of well-known zeolites and porous silicates. The ... Omar M. Yaghi and William A. Goddard III reported COFs as exceptional hydrogen storage materials. They predicted the highest ... Due to the exceptional porosity of COFs, they have been used extensively in the storage and separation of gases such as ... COF-1 and COF-5 exhibit high thermal stability (to temperatures up to 500 to 600 C), permanent porosity, and high surface areas ...
... but because hydrogen can cause porosity, its uses are limited.[30] Similarly, nitrogen can sometimes be added to argon to help ... Due to porosity problems in ferritic steels and limited benefits, however, it is not a popular shielding gas additive.[31] ... For GTAW of carbon and stainless steels, the selection of a filler material is important to prevent excessive porosity. Oxides ... Additionally, if the welding torch is too far from the workpiece the shielding gas becomes ineffective, causing porosity within ...
... especially when low-hydrogen electrodes are used.[citation needed] Porosity, often not visible without the use of advanced ... Porosity is caused when the gaseous shield did not sufficiently shield the molten weld metal while the bead is laid or while it ... Arc blow can also cause porosity in the weld, as can joint contamination, high welding speed, and a long welding arc, ... What happens is that the weld bead is overexposed to and absorbs; nitrogen, oxygen, and hydrogen from the atmosphere. When a ...
Hydrogen storage. References[edit]. *^ a b c d e f g h i Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; ... Bradley RH, Sutherland I, Sheng E (1996). "Carbon surface: Area, porosity, chemistry, and energy". Journal of Colloid and ... Research is being done testing various activated carbons' ability to store natural gas[1][2] and hydrogen gas.[1][2] The porous ... Activated carbon is used in methane and hydrogen storage,[1][2] air purification, solvent recovery, decaffeination, gold ...
These coating materials exhibit uniform distribution of fine particles and porous microstructures, which increased hydrogen ... and the retention of porosity. Stoichiometric reactions have also been carried out by reaction of attrition milled (wearing ...
In the production of hydrogen fluoride, calcium fluoride is treated with sulfuric acid, precipitating calcium sulfate. ... The conditions of dehydration can be changed to adjust the porosity of the hemihydrate, resulting in the so-called alpha and ...
The final color of each strand of hair will depend on its original color and porosity. Because hair's color and porosity across ... The combination of hydrogen peroxide and ammonia causes the natural hair to be lightened, providing a "blank canvas" for the ... Porosity of hair can affect the final shade. Porous hair often absorbs more color, which sometimes results darker than expected ... Semi-permanent hair coloring involves little or no developer, hydrogen peroxide or ammonia, and is thus less damaging to hair ...
Among the weak bonds, there is a distinction between polar bonds or hydrophilic bonds (hydrogen bonds and van der Waals bonds) ... used to reduce the porosity of metals and increase the density of many ceramic materials. This improves the material's ... Among them, for example, are van der Waals bonds between molecules and hydrogen bonds between water molecules in liquid water ...
... of chemical compounds of carbon and hydrogen, which may contain any number of other elements such as nitrogen, oxygen and the ... porosity, index of refraction and many others. This section discusses some physical properties of materials in the solid state ...
The porosity of the board-introduced during manufacturing to reduce the weight of the board, lowering construction time and ... Volatile sulphur compounds, including hydrogen sulphide, have been detected as emissions from the imported drywall and may be ...
... hydrogen cyanide, formaldehyde, ethanol, and ethane and perhaps more complex molecules such as long-chain hydrocarbons and ... "Small Body Density and Porosity: New Data, New Insights" (PDF). 37th Annual Lunar and Planetary Science Conference. 37: 2214. ...
For example, depending on surface porosity, 5-30 atomic layers of titanium carbide are hydrolyzed, forming methane within 5 ... to give a mixture of hydrogen and hydrocarbons. These compounds share features with both the inert interstitials and the more ...
These particles are irregularly shaped, with porosity ranging from fluffy to compact. The composition, size, and other ... Hydrogen chloride. *Hydrogen fluoride. *Hydrogen (molecular). *Hydroxyl radical. *Iron(II) oxide. *Magnesium monohydride cation ... with porosity about 40%). The densities of most IDPs captured in the Earth's stratosphere range between 1 and 3 g/cm³, with an ...
Singleton P and D Sainsbury (2001). "Hydrogen-oxidizing bacteria (the 'hydrogen bacteria'; knallgas bacteria)". Dictionary of ... sediment porosity, and grain size. These criteria indicate that certain sediment types, such as abyssal clays and siliceous ... and recombine to produce hydrogen peroxide (H2 O2), and molecular hydrogen (H2).[9] ... The products of this reaction are aqueous electrons (e−aq), hydrogen radicals (H·), protons (H+), and hydroxyl radicals (OH·).[ ...
In that case the wood should be charred at high temperature to reduce the residual amounts of hydrogen and oxygen that lead to ... Due to its porosity, it is sensitive to the flow of air and the heat generated can be moderated by controlling the air flow to ... Charcoal contains varying amounts of hydrogen and oxygen as well as ash and other impurities that, together with the structure ... Charcoal can also be used to reduce super heated steam to hydrogen (along with the formation of carbon monoxide): ...
Some scientists have reported methods of detecting hydrogen and methane in extraterrestrial atmospheres.[43][44] Habitability ... Bosak, Tanja; Souza-Egipsy, Virginia; Corsetti, Frank A.; Newman, Dianne K. (2004). "Micrometer-scale porosity as a ... nitrogen and hydrogen in organic matter; (c) multiple sulfur and oxygen isotope ratios of minerals; and (d) abundance ... "Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents". Proceedings of the National Academy ...
M (2011). "Two commensurate hydrogen-bonded monolayer structures of melamine on Ag(111)". Surface Science. 605: 1-6. doi: ... It results in concrete with a lower porosity and a higher mechanical strength, exhibiting an improved resistance to aggressive ... Such a self-assembly occurs due to the inter-molecular hydrogen bond interaction. This ordering was further investigated using ...
... hydrogen peroxide) leads to an increase in the surface roughness and porosity of composite resins.[63] However, the saliva may ... Hydrogen peroxide is an irritant and cytotoxic. Hydrogen peroxide with concentrations of 10% or higher can cause tissue damage ... The bleaching agent is either carbamide peroxide, which breaks down in the mouth to form hydrogen peroxide, or hydrogen ... hydrogen peroxide concentration. The legal percentage of hydrogen peroxide allowed to be given is 0.1-6%.[where?] Bleaching ...
407 hydrogen atoms, and 94 oxygen atoms (64% carbon, 8% hydrogen, and 29% oxygen by weight) which seems to be too high in ... the main parameter controlling the concrete porosity, and thus its mechanical strength, its diffusivity and its hydraulic ... An example of composition from an aspen[7] sample is 63.4% carbon, 5.9% hydrogen, 0.7% ash (mineral components), and 30% oxygen ...
Research is being done testing various activated carbons' ability to store natural gas[1][2] and hydrogen gas.[1][2] The porous ... Bradley RH, Sutherland I, Sheng E (1996). "Carbon surface: Area, porosity, chemistry, and energy". Journal of Colloid and ... Activated carbon is used in methane and hydrogen storage,[1][2] air purification, decaffeination, gold purification, metal ... Impregnated carbons are also used for the adsorption of Hydrogen Sulfide(H2S) and thiols. Adsorption rates for H2S as high as ...
Graying of hair may be triggered by the accumulation of hydrogen peroxide. Abnormally low levels of the enzyme catalase, which ... The final color of each strand is affected by its original color and porosity, so there will be subtle variations in color ... In a preliminary 2013 study, researchers treated the buildup of hydrogen peroxide which causes this with a light-activated ... breaks down hydrogen peroxide and relieves oxidative stress in patients suffering from vitiligo. Since vitiligo can cause ...
Hydrogen forms hydrogen sulfate H2SO4. Carbon forms (a blue) graphite hydrogen sulfate C+. 24HSO-. 4 • 2.4H2SO4.[120] Nitrogen ... Du Plessis M 2007, 'A Gravimetric Technique to Determine the Crystallite Size Distribution in High Porosity Nanoporous Silicon ... Extrapolating from the heavier hydrogen chalcogenides, namely hydrogen sulfide H2S, hydrogen selenide H2Se, and hydrogen ... Hydrogen. *Water (H2O), a well known oxide of hydrogen, is a spectacular anomaly.[158] ...
It took until 1952 for the first full hydrogen bomb to be detonated, so-called because it used reactions between deuterium and ... and a radiation detector which are lowered into boreholes to determine the properties of the surrounding rock such as porosity ... Hydrogen bombs obtain their enormous destructive power from fusion, but their energy cannot be controlled. Controlled fusion is ... This process of fusion occurs in stars, which derive their energy from hydrogen and helium. They form, through stellar ...
These can form hydrogen bonds with synthetic dyes. The efficiency of this enzyme is proportional to the number of hydrogen ... "The effect of crystal facets and induced porosity on the performance of monoclinic BiVO4 for the enhanced visible-light driven ... To enhance the catalytic abilities, a combination of Fe2+ cations, ultraviolet light, and hydrogen peroxide can be used and has ... of an Immobilized Iron Oxide for Catalytic Degradation of Azo Dye Reactive Black B with Catalytic Decomposition of Hydrogen ...
It could also be used to safely store hydrogen for use in a hydrogen based engine in cars.[42] ... glassy carbon contains a high proportion of closed porosity,[37] but contrary to normal graphite, the graphitic layers are not ... A similar claim can be made for hydrogen because most organic compounds also contain hydrogen.[citation needed] ... The simplest form of an organic molecule is the hydrocarbon-a large family of organic molecules that are composed of hydrogen ...
The transport-available porosity equals the total porosity less the pores which, due to their size, are not accessible to the ... Hydrogen (dis) - water (l). 25. 4.50×10−5. [3]. Hydrogen sulfide (dis) - water (l). 25. 1.41×10−5. [3]. ... εt is the porosity available for the transport (dimensionless),. δ is the constrictivity (dimensionless),. τ is the tortuosity ...
Urea breaks the hydrogen bonds between the base pairs of the nucleic acid, causing the constituent strands to anneal. Heating ... Stacking gels have a higher porosity relative to the separating gel, and allow for proteins to migrate in a concentrated area. ... Separating gels allow for the separation of proteins and have a relatively lower porosity. Here, the proteins are separated ... covalent forces such as hydrogen bonds and van der Waals forces. Macromolecular structure is dependent on the net effect of ...
Metallic zinc could be used as an alternative fuel for vehicles, either in a zinc-air battery[15] or to generate hydrogen near ... Power capacity is a function of several variables: cathode area, air availability, porosity, and the catalytic value of the ... Manufacturers caution against hydrogen build-up in enclosed areas. A short-circuited cell gives relatively low current. Deep ... Zinc corrosion can produce potentially explosive hydrogen. Vent holes prevent pressure build-up within the cell. ...
Hydrogen can also cause the embrittlement of metals. Hydrogen is a flammable gas, which is a safety concern if released from ... A typical design is a stack of fine metal wire meshes, with low porosity to reduce dead space, and with the wire axes ... One test showed hydrogen to be 5% (absolute) more efficient than helium (24% relatively) in the GPU-3 Stirling engine.[76] The ... Hydrogen's low viscosity and high thermal conductivity make it the most powerful working gas, primarily because the engine can ...
x capture from fossil-fuel utilization with combined renewable hydrogen production and large-scale carbon sequestration, 30 ... porosity etc., which correlate with different biochar properties. The atomic ratios of biochar, including H/C and O/C, ... both the H/C and O/C ratio decreased due to the release of functional groups which contain hydrogen and oxygen.[31] ...
The paper for holding the tobacco blend may vary in porosity to allow ventilation of the burning ember or contain materials ... Cigarette smoke contains over 7,000 chemical compounds, including arsenic, formaldehyde, hydrogen cyanide, lead, nicotine, ... Cigarette paper has been specially engineered by creating bands of different porosity to create "fire-safe" cigarettes. These ...
It reacts vigorously with water to form lithium hydroxide (LiOH) and hydrogen gas. Thus, a non-aqueous electrolyte is typically ... The value for ε, the porosity of the electrolyte, is 0.724.[150] ... which require only a hydrogen/oxygen recombination device and a ... titanium disulfide reacts to form hydrogen sulfide compounds, which have an unpleasant odour and are toxic to most animals. For ...
Hydrogen gas porosity is an aluminium casting defect in the form of a porosity or void in an aluminium casting caused by a high ... Hydrogen porosity can be reduced by reducing the amount of hydrogen in the liquid aluminium alloy, by degassing or sparging. ( ... Sometimes a small hydrogen concentration is intentionally maintained; some very fine hydrogen porosity can be preferable to ... A hydrogen analyzer can be used for direct measurement of hydrogen in liquid aluminium. Direct monitoring of hydrogen is ...
Nanoporous Molecular Sandwiches: Pillared Two-Dimensional Hydrogen-Bonded Networks with Adjustable Porosity ... Nanoporous Molecular Sandwiches: Pillared Two-Dimensional Hydrogen-Bonded Networks with Adjustable Porosity ... Nanoporous Molecular Sandwiches: Pillared Two-Dimensional Hydrogen-Bonded Networks with Adjustable Porosity ... Nanoporous Molecular Sandwiches: Pillared Two-Dimensional Hydrogen-Bonded Networks with Adjustable Porosity ...
Porosity may or may not be visible to the naked eye but can occasionally be found in the face of the weld. ... Stick welding porosity in a weld is considered poor quality. ... Porosity is often found when using low-hydrogen electrodes such ... but deep inside the weld porosity may exist. Porosity looks sponge like or like tiny bubbles in the weld. Porosity in a weld ... Although some porosity found at the beginning of a weld made with low hydrogen electrodes is not always apparent, it is ...
Influence of Metal-Organic Framework Porosity on Hydrogen Generation from Nanoconfined Ammonia Borane. In: Journal of Physical ... Fingerprint Dive into the research topics of Influence of Metal-Organic Framework Porosity on Hydrogen Generation from ... Influence of Metal-Organic Framework Porosity on Hydrogen Generation from Nanoconfined Ammonia Borane. / Chung, Jing Yang; Liao ... Influence of Metal-Organic Framework Porosity on Hydrogen Generation from Nanoconfined Ammonia Borane. Journal of Physical ...
We have fabricated reticulated porous ceramic (foam-type) structures made of ceria with dual-scale porosity in the millimeter ... b Laboratory for Hydrogen and Energy, Empa, 8600 Dübendorf, Switzerland c Institute for Geo- and Life Sciences, Crystallography ... Thermochemical CO2 splitting via redox cycling of ceria reticulated foam structures with dual-scale porosities P. Furler, J. ... The larger void size range, with dmean = 2.5 mm and porosity = 0.76-0.82, enables volumetric absorption of concentrated solar ...
Hydrogen assisted build-up of nano-porosity is addressed. Growth of sub-nanometer wide stalactitic pores owing to increasing ... The break-down of the barrier oxide is understood to be preceded by avalanching hydrogen pick-up in the alloy. Pore mediated ... aggregation of neutral oxygen vacancies offering a means to permeate hydrogen into the alloy is explored by density functional ... Hydrogen assisted build-up of nano-porosity is addressed. Growth of sub-nanometer wide stalactitic pores owing to increasing ...
2016). Amorphous, turbostratic and crystalline carbon membranes with hydrogen selectivity. Carbon 106, 93-105. doi: 10.1016/j. ... A better understanding of the inner structure, in terms of porosity textures of the Fe3O4-based carbon microspheres and of the ... Porosity and Porous Texture Analysis. N2-adsorption/desorption isotherms were obtained at 77 K (Micromeritics ASAP 2020 ... By now, it is worthy noticing that, together with SEM, the TEM analysis has a relevant role in investigating the porosity of ...
Effect of Hydrogen on Porosity a) Hydrogen in Filler b) Hydrogen in Shielding-Gas 6 1.5 g) Porosity in ml/100g Porosity in ml/ ... Hydrogen Content and Porosity during Welding Gas porosity caused by hydrogen is a major problem during welding of aluminium and ... Effect of hydrogen content on the width of the pore forming zone ♦ Effect of hydrogen on porosityPorosity in TIG welds TALAT ... Effect of Hydrogen Content on the Width of the Pore Forming Zone 4203.02.06 Effect of Hydrogen on Porosity 4203.02.07 Porosity ...
Pd Clusters Supported on Amorphous, Low-Porosity Carbon Spheres for Hydrogen Production from Formic Acid ACS Applied Materials ... Pd Clusters Supported on Amorphous, Low-Porosity Carbon Spheres for Hydrogen Production from Formic Acid Full article Общее. ... carbon spheres, formic acid, functional groups, hydrogen production, Pd acetate. Authors. Bulushev Dmitri A. 1,2,4 , Bulusheva ... Abstract: Amorphous, low-porosity carbon spheres on the order of a few micrometers in size were prepared by carbonization of ...
... which holds hydrogen that results in porosity. A weld puddle that freezes faster with aluminum - trapping hydrogen in the weld ... 2. Issues with porosity. The causes of porosity are very different with aluminum than with carbon steel. The materials oxide ... Using a helium-blend shielding gas can also help reduce hydrogen.. With carbon steel, porosity occurs because of the presence ... Also be sure to clean the material where the weld joints come together to avoid porosity or lack of fusion. Proper storage ...
... in particular hydrogen, from a fluid stream utilizing a plate membrane flattened with a wave spring on the low pressure side of ... Method for making a fine porosity filter element. US3338681. Dec 18, 1963. Aug 29, 1967. Union Carbide Corp. Apparatus for ... are good dissociation catalysts of hydrogen gas or hydrogen rich molecules to atomic hydrogen. The atomic hydrogen then ... Hydrogen purification method, hydrogen separation membrane, and hydrogen purification apparatus. US20120067211 *. Mar 22, 2011 ...
Global porosity. For global porosity, we use a seafloor porosity data set by Martin et al.58 and accounted for sediment ... Pastina, B. & LaVerne, J. A. Effect of molecular hydrogen on hydrogen peroxide in water radiolysis. J. Phys. Chem. A 105, 9316- ... Sediment samples were slurried with natural seawater to achieve a slurry porosity (φ) of ~0.83, which is the average porosity ... where i is alpha, beta, or gamma radiation; Am is radioactivity per mass solid; φ is porosity; ρ is density solid; \(E_i\) is ...
Hydrogen may have an effect on peak shifts and the influence of deformation or radiation has not been fully explored. In the ... 1) and porosities of up to ~30% (Vicenzi et al. 2003); the C isotopic composition (δ13C‰ is between -21 and -34) is extremely ... 2003). Defects containing hydrogen, labeled H1, and higher N aggregation centers, N + , 2 N 2 V + , and N 3 V , reported by ... 2004). More generally, hydrogen is critical to diamond formation in CVD processes, is present as "dangling bonds" (i.e. singly ...
Hydrogen Cracking (retak hidrogen). Hydrogen Cracking atau disebut juga delay cracking adalah salah satu mekanisme dari retak ... Macam macam Penyebab Porosity pada Penge…. Cacat Las Porositas adalah salah satu jenis cacat pengelasan yang disebabkan karena ...
Hydrogen Cracking (retak hidrogen). Hydrogen Cracking atau disebut juga delay cracking adalah salah satu mekanisme dari retak ... Macam macam Penyebab Porosity pada Penge…. Cacat Las Porositas adalah salah satu jenis cacat pengelasan yang disebabkan karena ...
Novel method to measure enamel surface porosity with hydrogen peroxide bleaching[J]. AMERICAN JOURNAL OF DENTISTRY,2009,22(5): ... Sound enamel was treated with 10, 20 and 30% solutions of hydrogen peroxide. Plastic strips were used to treat both sound and ... Etched enamel, similar to a 10-second exposure to lemon juice, was treated with 0.5, 1, 3, 5, 10, and 15% hydrogen peroxide for ... Dye uptake as measured by image analysis indicated an increase in surface porosity that was more evident with the acid modified ...
... depending on the hydrogen content [21]. A difference in hydrogen content might explain the observed thickness dependence of the ... attributed to an increased porosity [19]. The decrease of Youngs modulus with increasing thickness of the ITO-2 from 200 nm to ... The addition of hydrogen to the sputtering atmosphere widely suppressed crystallization in the 220 nm film. The XRD pattern of ... Pantchev, B.; Danesh, P.; Antonova, K.; Schmidt, B.; Grambole, D.; Baran, J. Effect of film thickness on hydrogen content in a- ...
Porosity is significantly reduced as revealed by optical metallography and 3D tomography. To reach these results the work was ... Not only the concentration of hydrogen is lower than by purging gas mixtures through the melt, it also reduces the oxide ... With the prototype 2 (LPDC/GC) a significant hydrogen degassing was verified. In principle a degassing is feasible in the ... Nevertheless the results for porosity and fracture elongation are similar the same like in the castings after the Impeller ...
A novel mesoporous hydrogen-bonded organic framework with high porosity and stability. ...
Sufficient porosity and tortuosity are needed to avoid polarization effects. An enhanced surface area on both sides of the ... Aim is to increase the hydrogen permeation of the membrane by modifying structure and surface area. The manufacturing of the ... Development of supported thin film membranes for hydrogen separation (MSc assignment). Announcing Institution: ... Oxide ceramic membranes for the separation of oxygen or hydrogen from gas mixtures are of great interest for different ...
hierarchical porosity (1) * high throughput experimentation (1) * homogeneous (1) * hydrogen (1) * hydrogenation (1) ... Additionally, the importance of the right choice of hydrogen donors and solvents is discussed. A wide range of compounds can be ... Microwave effects in heterogeneous catalysis: Application to gas-solid reactions for hydrogen production ...
The results confirm porosity formed in electron beam welded titanium-based alloys is associated with gas dynamics; hydrogen is ... First, porosity formed in electron beam welded titanium samples is characterised to rationalise the porosity formation ... Hence the key factors responsible for porosity formation need to be identified, and guidance to minimise porosity occurrence ... Porosity formed in electron beam welds is characterised using metallographic sectioning, high resolution X-ray tomography, ...
The porous matrix allows the flow of hydrogen therethrough to contact the hydride particles, yet supports the granules and ... The porous structure of the granules accommodates the expansion that occurs when the metal hydride particles absorb hydrogen. ... The matrix should have sufficient porosity for the hydrogen to permeate the structure. It should maintain its hydrogen- ... The increased porosity also allows hydrogen to more readily permeate to the hydride particles. ...
... including hydrogen porosity, hot cracking, and stress corrosion cracking. For this reason, friction stir welding has emerged as ... In this thesis, study of hydrogen trapping in alternate gate dielectric candidates such as HfO2 during annealing in hydrogen ... Evaluation of hydrogen trapping in HfO2 high-κ dielectric thin films. Description: Hafnium based high-κ dielectrics are ... Hydrogen is one of the most significant elements in semiconductor technology because of its pervasiveness in various deposition ...
In this thesis, study of hydrogen trapping in alternate gate dielectric candidates such as HfO2 during annealing in hydrogen ... A good approach is increasing porosity of the film. Recently, fluorinated silica xerogel films have been identified as ... Evaluation of hydrogen trapping in HfO2 high-κ dielectric thin films. Description: Hafnium based high-κ dielectrics are ... Hydrogen is one of the most significant elements in semiconductor technology because of its pervasiveness in various deposition ...
SULFUR DIOXIDE/HYDROGEN SULFIDE POROSITY TESTS ... Another type of porosity test for precious metal coatings is ... The test methods described in this Standard employ the use of hydrogen sulfide (H2S) which will affect silver and copper but ... This Standard sets out methods for assessing the degree of porosity in electroplated metallic coatings, such as gold, palladium ... when exposed to sulfur dioxide-hydrogen sulfide atmospheres. Electroplated coatings of non-tarnishing precious metals, such as ...
Microwave synthesis of ZnIn2S4/WS2 composites for photocatalytic hydrogen production and hexavalent chromium reduction. ... Synthesis and evaluation of novel MOF materials with Hiearchical porosity (Bristol University) ... Microwave synthesis of ZnIn2S4/WS2 composites for photocatalytic hydrogen production and hexavalent chromium reduction. ... Novel photocatalysts for the abatement of organic pollutants and hydrogen production (Chiang Mai University) ...
It showed about 95.8% methane conversion and 82.9% hydrogen yield at 700 °C and stable activity during 16 redox cycles. ... The loss of catalyst porosity during the reduction can be observed from reported pore volume (reduction from 0.161 cm3/g to ... Therefore, the amount of produced hydrogen is increased and subsequently hydrogen to carbon monoxide molar ratio is enhanced. ... and hydrogen production yield (. Y. H. 2. ) were calculated for evaluating the activity of catalyst/sorbents in the CLSMR ...
... and cause hydrogen embrittlement. The hydrogen present in the flame or atmosphere at high temperature reacts with the oxide, ... The steam bubbles exert high pressure in the metal structure, leading to cracks and joint porosity. Oxygen-free copper is not ... Noble gas+hydrogen (AWS type 9A). *Vacuum: Requires evacuating the work chamber. Expensive. Unsuitable (or requires special ... Nitrogen+hydrogen+carbon monoxide, cryogenic or purified (AWS type 6B): 70-99% N2, 2-20% H2, 1-10% CO. For copper, silver, ...
Density Porosity. Neutron Porosity. Gamma Ray Wireline Examples. Geophysical Methods for PPP. Seismic. Gravity. Magnetics. VSP ... Hydrogen Index (CNL). Nuclear Magnet resonance logs (NMR). Thermal Neutron Capture Cross-section (TDT). Down-hole gravity data ... Drilling porosity logs. Formation Pressure logs. Torque, Drag & Over-pull. Shale cuttings. Shale factor. Volume, shape, size of ... Relation of Porosity & lithology to effective stress. Eaton´s Method. Poissons from Shaliness Index. Daines Method ...
  • Purpose: To establish methods to quantitate the physical surface change, not the chemical color bleaching change, of enamel occurring with hydrogen peroxide treatment in solution and commercially available plastic strips. (bjmu.edu.cn)
  • Sound enamel was treated with 10, 20 and 30% solutions of hydrogen peroxide. (bjmu.edu.cn)
  • Etched enamel, similar to a 10-second exposure to lemon juice, was treated with 0.5, 1, 3, 5, 10, and 15% hydrogen peroxide for 24-hour exposure at 37 degrees C to obtain a dose response curve to this modified enamel. (bjmu.edu.cn)
  • Measurable surface change of etched enamel was detected with as low as 1% hydrogen peroxide in solution. (bjmu.edu.cn)
  • The surface change with 15% hydrogen peroxide was statistically significant. (bjmu.edu.cn)
  • Novel method to measure enamel surface porosity with hydrogen peroxide bleaching[J]. AMERICAN JOURNAL OF DENTISTRY,2009,22(5):283-289. (bjmu.edu.cn)
  • There are other developers (or catalysts) but Hydrogen Peroxide are the most widely used agents for haircolor. (style-hair-magazine.com)
  • Hydrogen Peroxide comes in different volumes and should be used according to how much hair you want to lift. (style-hair-magazine.com)
  • Lighteners are mixed with Hydrogen Peroxide, forming oxidation, which begins the haircoloring process. (style-hair-magazine.com)
  • Carbamide vs. hydrogen peroxide. (animated-teeth.com)
  • The science of carbamide and hydrogen peroxide whiteners. (animated-teeth.com)
  • It's hydrogen peroxide that creates tooth whitening. (animated-teeth.com)
  • The specific compound that breaks down to release free radicals is hydrogen peroxide. (animated-teeth.com)
  • Carbamide peroxide can be used in whitener formulations because when it's exposed to water it breaks down into hydrogen peroxide (and urea), which then breaks down and creates the whitening effect as described above. (animated-teeth.com)
  • In comparison, in-office bleaching systems typically use products that have a hydrogen peroxide content (HPC) of possibly 35% or more. (animated-teeth.com)
  • Studies evaluating the effects of hydrogen peroxide at about this same concentration (actually 3.0%) have not shown a carcinogenic risk. (animated-teeth.com)
  • Surprisingly, the everyday dosing of 10% carbamide peroxide whitener (3.6% hydrogen peroxide equivalent) used with tray technique comes close to the security limit for adults. (animated-teeth.com)
  • Influence of nanoporous titanium niobium alloy surfaces produced via hydrogen peroxide oxidative etching on the osteogenic differentiation of human mesenchymal stromal cells. (ukaachen.de)
  • Both of these factors were increased by the removal of residual organic material, using hydrogen peroxide. (spie.org)
  • Further progress was made when Guilbault and Lubrano [ 3 ] determined glucose in blood on the basis of amperometric monitoring of the liberated hydrogen peroxide. (springer.com)
  • The cytotoxicity is signalled by increased content of hydrogen peroxide (H 2 O 2 ) causing lipid peroxidation followed by porosity in plasma membrane. (degruyter.com)
  • Weird, but true: When your hair is being bleached (usually with hydrogen peroxide, the most common agent), swelling is one of the first steps in the process. (oyetimes.com)
  • The flux coatings major task is to vaporize and form a shielding gas to protect the weld puddle from nitrogen, hydrogen and oxygen. (lincolnelectric.com)
  • Growth of sub-nanometer wide stalactitic pores owing to increasing aggregation of neutral oxygen vacancies offering a means to permeate hydrogen into the alloy is explored by density functional theory. (chalmers.se)
  • To combat this, choose steel filler metals that include deoxidizers, which help tie up the oxygen and keep it from forming porosity. (millerwelds.com)
  • The combustion of hydrogen with oxygen produces an exhaust of only water. (nanowerk.com)
  • Although NOM has no direct impact on The dry matter consists of complex organic matter that is composed primarily of carbon, oxygen, and hydrogen. (ecoloinfo.com)
  • Polymorph nickel titanate nanofibers as bifunctional electrocatalysts towards hydrogen and oxygen evolution reactions. (americanelements.com)
  • Molten metal is very reactive to oxygen, nitrogen and hydrogen from the atmosphere, if exposed to it. (lincolnelectric.com)
  • Here we provide evidence that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment. (nih.gov)
  • Direct monitoring of hydrogen is possible using an on-line quantitative measurement technology based on a closed-loop gas recirculation method though a porous ceramic probe. (wikipedia.org)
  • We have fabricated reticulated porous ceramic (foam-type) structures made of ceria with dual-scale porosity in the millimeter and micrometer ranges. (rsc.org)
  • Samples are thermally reduced at 1773 K and subsequently oxidized with CO 2 at temperatures in the range 873-1273 K. On average, CO production rates are ten times higher for samples with 0.44 strut porosity than for samples with non-porous struts. (rsc.org)
  • The porous structure of the granules accommodates the expansion that occurs when the metal hydride particles absorb hydrogen. (google.com)
  • The porous matrix allows the flow of hydrogen therethrough to contact the hydride particles, yet supports the granules and contains the hydride fines that result from repeated absorption/desorption cycles. (google.com)
  • Comparing to the first two ref pictures it contains a lot of disperse porous phase (marked on the pic) which increases the coating porosity significantly (up to 24-26%) although most of parameters are the same. (gordonengland.co.uk)
  • Other research interests include structure property relationships in MOFs (specifically as they apply to alternative fuel storage, including natural gas and hydrogen), stimuli-responsive materials for chemical toxin capture and drug delivery systems, and step-wise synthesis of advanced porous materials. (uvawise.edu)
  • In the Snelling patent a mixture of gases including hydrogen is brought into contact with one side of a very thin sheet or film of palladium which is maintained at an elevated temperature and is supported by a base of porous earthenware or some other ceramic material. (google.com)
  • Ao Z, Dou S, Xu Z, Jiang Q, Wang G (2014) Hydrogen storage in porous graphene with Al decoration. (springer.com)
  • Thomas KM (2007) Hydrogen adsorption and storage on porous materials. (springer.com)
  • Dündar-Tekkaya E, Karatepe N (2014) Hydrogen adsorption of carbon nanotubes grown on different catalysts. (springer.com)
  • Jhi SH, Kwon YK (2004) Hydrogen adsorption on boron nitride nanotubes: a path to room-temperature hydrogen storage. (springer.com)
  • Panella B, Hirscher M, Pütter H, Müller U (2006) Hydrogen adsorption in metal-organic frameworks: Cu-MOFs and Zn-MOFs compared. (springer.com)
  • According to the literature, the effect of organic species on metal adsorption on oMWCNTs is mainly attributed to the complexation between organic materials, metal ions, and surface functional groups of oMWCNTs by hydrophobic interaction, electrostatic attraction or repulsion, hydrogen bonding between the −OH and the tube surface −OH or−COOH groups, and π-π interactions between the phenolics and the carbon nanotubes [20], [55]. (nih.gov)
  • The porosity of films was studied using a new technique developed in which water adsorption isotherms are plotted using ellipsometry. (spie.org)
  • Amorphous, low-porosity carbon spheres on the order of a few micrometers in size were prepared by carbonization of squalane (C30H62) in supercritical CO2 at 823 K. The spheres were characterized and used as catalysts' supports for Pd. (catalysis.ru)
  • His research group, in collaboration with that of Dr. Peter Budd (Manchester University), recently invented a novel class of organic materials termed 'Polymers of Intrinsic Microporosity' (PIMs), which show great promise as adsorbents, heterogeneous catalysts, gas separation membranes and organic hydrogen storage materials. (rsc.org)
  • The availability of efficient hydrogen evolution reaction (HER) catalysts is of high importance for solar fuel technologies aimed at reducing future carbon emissions. (osti.gov)
  • The selectivity to light olefins was significantly increased as a result of modification in acidity and porosity of the monolith catalysts, which in turn mitigated the hydrogen transfer, hence suppressing the formation of paraffin and aromatics. (aiche.org)
  • This Standard sets out methods for assessing the degree of porosity in electroplated metallic coatings, such as gold, palladium and rhodium, that cover undercoats and basis metals that form visible compounds due to coating porosity, when exposed to sulfur dioxide-hydrogen sulfide atmospheres. (ihs.com)
  • The test methods described in this Standard employ the use of hydrogen sulfide (H2S) which will affect silver and copper but not nickel or tin, and, for thicker coatings, the additional use of sulfur dioxide (SO2) which will produce visible effects on any basis metal or undercoat. (ihs.com)
  • During short-term testing, wells produced oil and gas with, unexpectedly, the highest hydrogen sulfide (H 2 S) content of any reservoir so far discovered in Kuwait. (onepetro.org)
  • This type of porosity can be avoided if the operator is trained to strike the arc correctly. (lincolnelectric.com)
  • Another type of porosity test for precious metal coatings is given in AS 2331.3.6. (ihs.com)
  • As the severity of dental fluorosis increases, the depth of the enamel involvement and the degree of porosity increases. (fluoridealert.org)
  • Although diagenetic increase in porosity is favorable to the accumulation of hydrocarbons, reduction in porosity may be desirable in some instances because the rock itself may serve as a trap for the hydrocarbon accumulation. (ku.edu)
  • 1 , 2 Herein, we report the rapid synthesis of customized zeolite monoliths with various compositions and hierarchical porosity (macro-meso-micro) using 3D printing technique. (aiche.org)
  • The 3D-printed zeolite monoliths exhibited hierarchical porosity with pore sizes ranging from 1.5 nm to 1 µm. (aiche.org)
  • El Far R, Diaz-Droguett DE, Rojas S, Avila JI, Romero CP, Lievens P, Cabrera AL (2012) Quantitative determination of hydrogen absorption by Pd cluster-assembled films using a quartz crystal microbalance. (springer.com)
  • This article discusses hydrogen absorption during aluminum melting and casting and assesses methods to evaluate and remove hydrogen. (thefreelibrary.com)
  • Hydrogen absorption also increases with higher ambient relative humidity. (thefreelibrary.com)
  • Not only the concentration of hydrogen is lower than by purging gas mixtures through the melt, it also reduces the oxide content, increases the density (porosity is lower) and the mechanical properties of the final material. (europa.eu)
  • Examining organic porosity, we can hypothesize that formation of the connected pore system increases with thermal maturation. (onepetro.org)
  • The solubility of hydrogen in molten aluminum increases with temperature (Fig. 1). (thefreelibrary.com)
  • Bleaching also increases porosity, your hair's ability to absorb moisture. (oyetimes.com)
  • Hydrogen released from chemical hydride ammonia borane (AB, NH 3 BH 3 ) can be greatly improved when AB is confined in metal-organic frameworks (MOFs), showing reduced decomposition temperature and suppressed unwanted byproducts. (elsevier.com)
  • Nanocubes act as a storage medium for hydrogen: A possible storage medium for hydrogen are nanocubes made of metal organic frameworks (MOFs). (nanotech-now.com)
  • some very fine hydrogen porosity can be preferable to internal voids caused by shrinkage. (wikipedia.org)
  • Figure 2 portrays a classical distinction between shrinkage porosity and gas porosity. (thefreelibrary.com)
  • Shrinkage porosity indicates a lack of feed metal reaching the place where it is needed--the last portion of the casting to solidify. (thefreelibrary.com)
  • Consequently, the resultant porosity follows the solidification path and the dendrite boundaries, and shrinkage porosity displays a ragged, irregular edge. (thefreelibrary.com)
  • The resultant increased partial pressure is related to the concentration of hydrogen in the melt. (thefreelibrary.com)
  • 7 Effect of Hydrogen Content on the Width of the Pore Forming Zone. (slideshare.net)
  • The solubility of hydrogen in solid aluminium is much smaller than in liquid aluminium. (wikipedia.org)
  • Hydrogen forms whenever molten aluminium comes into contact with water vapor, and easily dissolves into the melt. (wikipedia.org)
  • I just did a little bit of goggleing, and it says that hydrogen comes from water vapor or grease. (millerwelds.com)
  • PEM fuel cell systems have an overall efficiency exceeding 30% (compared to 22-25% for diesel generators), and when run on pure hydrogen, their only emission is water vapor. (ieee.org)
  • The screen permeability was found to increase with increasing screen porosity and inclination. (sae.org)
  • Empirical equations are developed giving the predicted pressure drop and permeability for screens with a given porosity and inclination. (sae.org)
  • Formations in this deep structure have very low porosity and permeability. (onepetro.org)
  • 3) upon reaching the downstream surface of the membrane the atomic hydrogen reconverts to molecular hydrogen and escapes from the surface. (google.com)
  • Depending on the quality of the steel and potential exposure to atomic hydrogen, in principle, embrittlement can accelerate propagation of cracks, reducing the pipeline's service life by 20 to 50 percent. (automatedhome.co.uk)
  • This is only likely, though, if the pipeline already has fractures and is subjected to dynamic stresses due to fluctuating internal pressure while at the same time being exposed to atomic hydrogen. (automatedhome.co.uk)
  • Hydrogen porosity can be reduced by reducing the amount of hydrogen in the liquid aluminium alloy, by degassing or sparging. (wikipedia.org)
  • The break-down of the barrier oxide is understood to be preceded by avalanching hydrogen pick-up in the alloy. (chalmers.se)
  • Atwood, R.C. and Lee, P.D., "Simulation of the Three Dimensional Morphology of Solidification Porosity in an Aluminium-Silicon Alloy", Acta Mat. (imperial.ac.uk)
  • A degree of 'alloy specificity' also exists--at a given molten metal temperature, less hydrogen is soluble in 319 alloy than in 356 alloy, for example. (thefreelibrary.com)
  • Large pores and high organic porosity do not occur in all OM within a sample and OM with no significant visible porosity does occur in high-stress locations and in thin sheets between mineral grains. (onepetro.org)
  • Within their very roomy pores, MOFs can effectively store gases such as hydrogen or carbon dioxide, making the nanostructures of special interest to engineers as well as scientists. (isssource.com)
  • MOFs are highly crystalline structures with nanometer-sized pores that allow them to store hydrogen and other high-energy gases. (nanotech-now.com)
  • The FTIR spectra of carbonado-diamond mostly depict the presence of single nitrogen impurities, and hydrogen. (scribd.com)
  • To meet this need a variety of methods have been conceived and developed for economically separating pure hydrogen from fluid mixtures containing free hydrogen or of inexpensively purifying hydrogen gases containing excessive quantities of impurities. (google.com)
  • At the forefront of these impurities is hydrogen, the only gas soluble in molten aluminum, because it creates porosity in castings. (thefreelibrary.com)
  • 3. The method of claim 1 , wherein said intrinsic characteristic is selected from the group consisting of density, hydrogen index, salinity, sigma, neutron slowing down length, neutron slowing down time, compositional information from neutron induced gamma ray spectroscopy, and photoelectric effect. (google.com.au)
  • A standoff compensation system is disclosed for use in an LWD system implementing gamma density and/or neutron porosity measurements. (google.com)
  • More particularly, the present invention relates to a system for increasing the accuracy of measurements made using nuclear radiation sensors, including particularly neutron porosity and gamma density measurements. (google.com)
  • The present invention includes a downhole processor for determining a weighting factor for the density and/or porosity measurements based upon the measured standoff distance. (google.com)
  • A weld puddle that freezes faster with aluminum - trapping hydrogen in the weld - is another main cause of porosity in the weld. (millerwelds.com)
  • It showed about 95.8% methane conversion and 82.9% hydrogen yield at 700 °C and stable activity during 16 redox cycles. (mdpi.com)
  • As immature kerogen undergoes thermal maturation, hydrogen bonds are initially broken resulting in the early formation of oil, then wet gas, and finally of pure methane. (onepetro.org)
  • This paper presents the performance and emission characteristics of a gas mixture of equal volumes of hydrogen, CO, and methane. (sae.org)
  • This example investigates the thermal decomposition of methane into hydrogen and solid carbon, over a catalyst. (comsol.com)
  • Atwood, R.C. and Lee, P.D. "A Three Phase Model of Hydrogen Pore Formation During the Equiaxed Dendritic Solidification of Aluminum-Silicon Alloys", Met. (imperial.ac.uk)
  • Using a field-emission scanning electron microscope (FESEM) on argon-ion polished shale samples, images show that most of the porosity occurs within organic matter (OM) and that the pore geometry and characteristics vary with increasing thermal maturity. (onepetro.org)
  • Furthermore, to control both particle and pore size in nanoporous palladium (Pd)-based hydrogen storage materials, first we created uniformly sized copper particles of about 1 μm diameter by the reduction of copper sulfate with ascorbic acid. (osti.gov)
  • Aluminium foundries want to produce high-quality aluminum castings with minimum porosity. (wikipedia.org)
  • Hydrogen causes porosity in aluminum products leading to many casting defects, reduced mechanical properties like fatigue and lower corrosion resistance. (wikipedia.org)
  • An on-line method of measuring hydrogen in aluminum is then required to characterize and optimize the process, which helps ensure the quality of outgoing products and monitors the performance of these degassing processes. (wikipedia.org)
  • The causes of porosity are very different with aluminum than with carbon steel. (millerwelds.com)
  • The material's oxide layer is the main reason for porosity on aluminum. (millerwelds.com)
  • When welding aluminum, set the heat high enough so the puddle stays fluid longer, allowing the hydrogen to escape. (millerwelds.com)
  • Porosity in aluminum is caused by one thing and one thing only: Hydrogen. (millerwelds.com)
  • Hydrogen enters molten aluminum easily. (thefreelibrary.com)
  • The presence of hydrogen in the weld pool-from the filler metal and the aluminum itself-also can lead to porosity. (metalformingmagazine.com)
  • Hydrogen is very soluble in aluminum and can easily become trapped as the weld solidifies. (metalformingmagazine.com)
  • Porosity formed in electron beam welds is characterised using metallographic sectioning, high resolution X-ray tomography, residual gas analysis (RGA), scanning electron microscopy (SEM) and energy and wavelength dispersive spectroscopy (EDS/WDS) analysis. (bham.ac.uk)
  • A little understanding of how these electrodes differ and the consequences of improper electrode handling will pay big dividends in better weld quality and fewer porosity defects. (lincolnelectric.com)
  • For a given hydrogen concentration in the liquid state, the faster the solidification rate, the fewer problems with resultant porosity. (thefreelibrary.com)
  • Because not all sections of the casting solidify at the same rate, ample opportunity exists for hydrogen buildup in the remaining liquid metal during solidification. (thefreelibrary.com)
  • The original paper noted that porosity stems from the interactions between dissolved hydrogen, the presence of heterogenous nucleation sites (oxides) and solidification conditions. (thefreedictionary.com)
  • Even though Pt electrodes are excellent HER electrocatalysts, commercialization of large-scale hydrogen production technology requires finding an equally efficient, low-cost, earth-abundant alternative. (osti.gov)
  • For example, the Chinese city of Changshu runs a large-scale hydrogen programme - in a few years they plan to switch completely to hydrogen energy. (fuelcellsworks.com)
  • The improved catalyst, expected to be the subject of an Oct. 7 Nature Communications paper ( 'Understanding catalysis in a multiphasic two-dimensional transition metal dichalcogenide' ), has already released four times the amount of hydrogen ever produced by molly from water. (nanowerk.com)
  • Stick welding porosity in a weld is considered poor quality. (lincolnelectric.com)
  • 5 Hydrogen Content and Porosity during Welding. (slideshare.net)
  • This thesis is concerned with the porosity formation mechanism during electron beam welding of titanium-based alloys. (bham.ac.uk)
  • During the welding of titanium alloys for aerospace engine applications, porosity is occasionally found in the solidified welds. (bham.ac.uk)
  • A slight breeze can blow the shielding away and cause porosity, therefore welding outdoors is usually avoided unless special windscreens are erected. (lincolnelectric.com)
  • Porosity is often found when using low-hydrogen electrodes such as E-7018, and it may be difficult to establish why this occurs. (lincolnelectric.com)
  • With carbon steel, porosity occurs because of the presence of carbon monoxide and nitrogen in the weld. (millerwelds.com)
  • Porosity occurring within organic matter is well documented in gas shales but also occurs in the less thermally mature oil shales. (onepetro.org)
  • Fast-reacting SELECT FAMILY adsorbents are engineered using enhanced porosity control for improved activity. (slb.com)
  • 55-16) This invention relates to purification of hydrogen or its separation from a mixture of gases by diffusion through a hydrogen-permeable membrane. (google.com)
  • The larger specific surface area and high porosity on the nanometer scale enable MOFs to hold relatively large amounts of these gases. (nanotech-now.com)
  • Solidifying metal must reject the hydrogen or resultant castings will suffer from porosity. (thefreelibrary.com)
  • Hence the key factors responsible for porosity formation need to be identified, and guidance to minimise porosity occurrence needs to be provided. (bham.ac.uk)
  • First, porosity formed in electron beam welded titanium samples is characterised to rationalise the porosity formation mechanism. (bham.ac.uk)
  • Second, models based on sound physical principles are built to aid understanding of porosity formation, and to provide predictive capability. (bham.ac.uk)
  • hydrogen is very likely to be responsible for porosity formation. (bham.ac.uk)
  • In this investigation, we consider the mechanisms of formation of two types of porosity: primary and secondary, their characterization and their effects on fracture, fatigue and failure behavior of these alloys. (tms.org)
  • Enamel fluorosis results from increased porosity in the formed enamel, probably due to a delay in the removal of amelogenin proteins during enamel formation. (fluoridealert.org)
  • Metallic species improve the breakthrough capacity as well as they lead to the formation of Lewis acid-base interactions, hydrogen-bonding or complexation. (springer.com)
  • The core analysis of the Middle Marrat formation shows that dolomitization plays a major role for matrix-porosity enhancement, which is responsible for good reservoir character. (onepetro.org)
  • Mineral trapping of CO2 in a storage formation is hampered by hydrogen sulphide (H2S), for example. (platformlondon.org)
  • An apparatus for extracting a gas, in particular hydrogen, from a fluid stream utilizing a plate membrane flattened with a wave spring on the low pressure side of the membrane and a turbulence generator on the high pressure side. (google.com)
  • More particularly the invention is concerned with a method for separating hydrogen in a substantially pure form by means of a novel membrane which is permeable only to hydrogen. (google.com)
  • The Hunter patent teaches the use of a hydrogen-permeable membrane essentially consisting of a silverpalladium composition containing from to 50 percent of silver. (google.com)
  • These observations reveal that dipteran endoparasitoid invasion induced H 2 O 2 production in the hemocytes causing cytotoxicity, lipid peroxidation and membrane porosity that suppressed both humoral- and cell-mediated immune responses of hemocytes in B. mori . (degruyter.com)
  • Therefore, if the operator lowers the electrode into the puddle immediately, some porosity may result at the beginning of the weld, which is caused by insufficient amount of coating on the steel core wire. (lincolnelectric.com)
  • Then, when the electrode is lowered to the work, the weld will be properly shielded, and porosity will be minimized. (lincolnelectric.com)
  • 7 . A fuel cell electrode manufacturing method according to claim 1 , wherein the first electrode layer is divided into two layers, a first layer on the side away from the ion exchange film and a second layer on the side in contact with the ion exchange film, and the porosity of the second layer is lower than the porosity of the first layer. (google.co.uk)
  • 10 . A fuel cell electrode manufacturing method according to claim 7 , wherein to make the porosity of the second layer lower than the porosity of the first layer, a solution for making the second layer is applied with a higher atomization energy than a solution for making the first layer. (google.co.uk)
  • That hydrated oxide layer absorbs moisture, which holds hydrogen that results in porosity. (millerwelds.com)
  • Porosity is used to measure how fast your hair absorbs moisture. (style-hair-magazine.com)
  • Because of the presence of the large amount of uncured hydroxyl groups and the high porosity, the films absorb moisture resulting in property variation as a function of moisture level and eventual deterioration, and allow electrical and gas leakage and optical loss. (google.co.uk)
  • It is an object of this invention to provide sol-gel preparation of uniformly and highly dense low porosity titania forms containing only a small amount of hydroxyl groups and possessing a high refractive index, which do not absorb moisture and thus are property stable regardless of humidity level and resistant to humidity induced deterioration and which prohibit electrical and gas leakage and optical loss. (google.co.uk)
  • Here, high porosity, metal-organic framework (MOF) films have been used as scaffolds for the deposition of a Ni-S electrocatalyst. (osti.gov)
  • 30,000X) show the OM is composed of spherical to cylindrical units, 7-45 nm in diameter dispersed in an organic matrix, where the porosity has developed within this arrangement. (onepetro.org)
  • The presence of minerals within the OM may have an effect on visible organic porosity size and distribution. (onepetro.org)
  • Products and methods for controlling the porosity and permeation of a web are provided using a curable thixotropic shear thinnable polymer composition that preferably encapsulates a plurality of fibers of the web and/or forms an internal layer within the web. (google.es)
  • The RPT is a semi-quantitative method with limited accuracy that provides an indication of the hydrogen level. (wikipedia.org)
  • The closed loop recirculation is a proven method of directly monitoring hydrogen in molten aluminium. (wikipedia.org)
  • It features low hydrogen, less than 4 ml/100 g that has resistance to moisture reabsorption which helps prevent hydrogen cracking and aids in elimination of starting porosity. (airgas.com)
  • For example, increasing porosity in the GDL allows hydrogen and air to enter more freely and moisture to leave more freely, but might decrease electrical conductivity. (ieee.org)
  • 2019. Microwave synthesis of ZnIn2S4/WS2 composites for photocatalytic hydrogen production and hexavalent chromium reduction . (cardiff.ac.uk)
  • Less-pure CO2 waste streams, also containing other substances like SOx, NOx, hydrogen sulphide or even mercury, are significantly cheaper to generate (albeit with the possibility of higher transport costs), requiring less technological investment and energy to separate from a flue gas, coal gasification process, etc3. (platformlondon.org)
  • 1-h) change in the hydrogen sulphide concentration within the sediment more than 12 mm below the oxic zone, a change explicable by transmission of electrons but not by diffusion of molecules. (nih.gov)
  • Recent major developments, including rocket engines and fuel cells, have greatly increased the need for substantially pure hydrogen. (google.com)
  • Hydrogen could be used as an important feedstock in different chemical and petrochemical processes such as methanol, ammonia and hydrochloric acid production. (mdpi.com)
  • In recent years, production of hydrogen could be performed by various processes such as electrolysis, biomass gasification and reforming [ 5 , 16 , 17 , 18 , 19 , 20 ]. (mdpi.com)
  • In Chou s measured words, The idea was to understand the changes in the molecular structure of molybdenum disulfide (MOS 2 ), so that it can be a better catalyst for hydrogen production: closer to platinum in efficiency, but earth-abundant and cheap. (nanowerk.com)
  • Conducting polymers are versatile materials for creation of biosensors due to their rapid production, controlled thickness, and porosity, as well as easy electropolymerization on various surfaces. (springer.com)
  • Stepan Danilov noted that the sphere of hydrogen cell production in Russia is still in its infancy - there are separate enterprises, but the niche as a whole is not filled. (fuelcellsworks.com)
  • The Company's latest pre-commercial Hydrogen production system prototype cost effectively optimizes continuous production with sharply increasing efficiencies without employing consumables nor external power for neutralizing the produced Hydrogen ions. (altenergymag.com)
  • The advanced reactor design is considered a major improvement in the system's economic viability for early prospective commercialization of the Phoenix Hydrogen production technology. (altenergymag.com)
  • With exclusive control of its proprietary Hydrogen production technologies, the Phoenix efforts will include the compounding of Hydrogen with captured carbon emissions. (altenergymag.com)
  • We experimentally quantified H 2 yields for α- and γ-irradiation of pure water, seawater, and seawater-saturated marine sediment with a typical abyssal clay porosity (80-85%) for all abundant marine sediment types (abyssal clay, nannofossil-bearing clay (calcareous marl), clay-bearing siliceous ooze, calcareous ooze, and lithogenous sediment), which collectively cover ~70% of Earth's surface. (nature.com)
  • Results: The digital photography-image analysis system and scanning electron microscopy (SEM) were effective in detecting enamel surface porosity and structure disruptive changes, respectively. (bjmu.edu.cn)
  • Dye uptake as measured by image analysis indicated an increase in surface porosity that was more evident with the acid modified surface. (bjmu.edu.cn)
  • The argon bubbles rise to the surface, bringing with them some of the dissolved hydrogen. (wikipedia.org)
  • But here s the rub: While the edges of these nanostructures match platinum in their ability to catalyze hydrogen, the relative immense surface area of their sliding interiors are useless because their molecular arrangements are different from their edges. (nanowerk.com)
  • The affected enamel does not mature and has surface and subsurface porosities. (fluoridealert.org)
  • It is characterized by increased porosity (or hypomineralization) of the subsurface enamel and well mineralized surface layer of enamel. (fluoridealert.org)
  • Dental fluorosis is defined as a permanent hypomineralization of enamel, characterized by greater surface and subsurface porosity than in normal enamel, that results from excess fluoride (F) reaching the developing tooth during developmental stages… Excess F available to the enamel during maturation disrupts mineralization and results in excessive retention of enamel proteins. (fluoridealert.org)
  • The Micromeritics® TriStar II Plus is a fully automated surface area and porosity analyzer that delivers a rapid high throughput analysis with high accuracy. (micromeritics.com)
  • Micromeritics MicroActive data reduction and control software enables the user to interactively calculate surface area and porosity. (micromeritics.com)
  • Particles having rough surfaces or internal porosity will generally exhibit higher specific surface areas. (micromeritics.com)
  • Surface area and porosity characteristics affect the selectivity of an adsorbent. (micromeritics.com)
  • A hydrogen analyzer can be used for direct measurement of hydrogen in liquid aluminium. (wikipedia.org)
  • An example of analyzer for direct hydrogen measurement in liquid aluminium is the Accurity. (wikipedia.org)
  • Hydrogen storage capacities were investigated for two forms of MoO 3 nanomaterial, amorphous of low crystallinity, and other highly crystalline, using the quartz crystal microbalance technique. (springer.com)
  • Then, Pd-capped samples were measured using longer H2 exposure times of 30 min, finding that Pd-capped crystalline MoO 3 sample exhibited higher hydrogen storage capacity than its amorphous counterpart. (springer.com)
  • The aim being to establish a relationship between the porosity and the pressure drop characteristics of a given material at various angles of inclination to the free-stream flow. (sae.org)
  • A novel class of molecular crystals based on two-dimensional hydrogen (H)-bonded networks comprising guanidinium ions and the sulfonate groups of alkane- or arenedisulfonate ions is described. (sciencemag.org)
  • The highly defective SNTO manifests properties similar to metallic Ni and favours H2 evolution through the hydrogen evolution reaction (HER) by adsorbing more H+ ions on active sites. (americanelements.com)
  • In contrast, the large bamboo structured NTO nanofibers which have lesser porosity and SNTO content cage the bigger (OH)ads ions at their catalytic sites to facilitate OER performance. (americanelements.com)
  • A small volume of carrier gas, usually nitrogen, is brought in contact with the melt by means of an immersed probe, and is continuously recirculated in the closed loop until its hydrogen content reaches equilibrium with the vapor pressure of H2 in the melt. (wikipedia.org)
  • The lack of identifiable nitrogen aggregates in the infrared spectra, the presence of features related to hydrocarbon stretch bonds, and the resemblance of the spectra to CVD and presolar diamonds indicate that carbonado-diamonds formed in a hydrogen-rich interstellar environment. (scribd.com)
  • This is extended to a space and time dependent model where the porosity decay due to carbon deposition is accounted for. (comsol.com)
  • Hydrogen gas porosity is an aluminium casting defect in the form of a porosity or void in an aluminium casting caused by a high level of hydrogen gas (H2) dissolved in the aluminium at liquid phase. (wikipedia.org)
  • The mesh has a porosity as high as ∼91% in volume and was prepared at T ≤ 160 °C. The effectiveness of the TiO 2 /PES mesh under UV was proved by Methylene Blue (MB) dissociation experiments and related to the TiO 2 coverage properties, namely its thickness (∼15 nm), its nano-structuring (grains diameter 8-10 nm) and lattice structure (anatase) that improve the photo-activity action. (rsc.org)
  • The combination of electro-spinning plus sputtering processes lays the basis for high porosity and low cost, high throughput, high yield and flexible purifying filter technologies. (rsc.org)
  • It's divided into low, average, and high porosity. (style-hair-magazine.com)
  • These represent an entirely new class of adsorbent materials which show great potential for a wide range of application in areas such as: supported homogeneous catalysis, high-efficiency gas-separation and the storage of hydrogen. (rsc.org)
  • The degassing step reduces the occurrence of hydrogen gas porosity. (wikipedia.org)
  • The confluence of all three factors seems unlikely, however: Under normal operating conditions, there should be little load alternation, and only molecular hydrogen (H2) is conveyed. (automatedhome.co.uk)
  • Attempting to weld over the oxide layer will result in porosity. (millerwelds.com)
  • Also be sure to clean the material where the weld joints come together to avoid porosity or lack of fusion. (millerwelds.com)
  • Hydrogen in the melt diffuses into the carrier gas and is allowed to equilibrate. (thefreelibrary.com)