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Marcello Ponsiglione speaking at BIRS workshop, Analysis of Dislocation Models for Crystal Defects, on Tuesday, June 27, 2017 on the topic: Variational models for dislocations at grain boundaries.
Journal Article: Effects of local structure on helium bubble growth in bulk and at grain boundaries of bcc iron: A molecular dynamics study ...
Quartzofeldspathic ultramylonites from the Alpine Fault Zone, one of the worlds major, active plate boundary-scale fault zones have quartz crystallographic preferred orientations (CPO) and abundant low-angle (,10° misorientation) boundaries, typical microstructures for dislocation creep-dominated deformation. Geometrically necessary dislocation density estimates indicate mean dislocation densities of ~109 cm-2. A significant proportion (~30%) of grain boundaries (,10° misorientation) are decorated by faceted pores, commonly with uniformly-oriented pyramidal shapes. Only grain boundaries with ,10° misorientation angles in polymineralic aggregates are decorated by pores. Mean grain boundary pore densities are ~5 × 108 cm-2. Grain boundary pores are dissolution pits generated during syn-deformational transient grain boundary permeability, nucleating on dislocation traces at dilatant grain boundary interfaces. They have not been removed by subsequent grain boundary closure or annealing. Pore ...
Gresham, OR - Legacy Mount Hood Medical Center significantly advanced its cancer care capabilities recently with the launch of the latest generation of the Elekta Infinity™ linear accelerator, one of the most technologically advanced forms of cancer treatment. The linear accelerator enables Legacy Cancer Institutes Mount Hood-based team of radiation oncology specialists to deliver the most precise and effective radiation treatments available today directly to patients in their community. Specifically, the new equipment delivers radiation directly and aggressively to the tumor while sparing the surrounding healthy tissue-essentially shrink-wrapping the cancer in radiation. This level of precision minimizes unnecessary radiation exposure and potential long-term side effects of radiation therapy.. Legacy Cancer Institute is thrilled to bring this caliber of cancer care directly to patients in East County, said Kathryn Panwala, M.D., Legacy Cancer Institute radiation oncologist based at Mount ...
Bertin Instruments products and equipment for Monitoring and Testing. Including SpectroTRACER - Intelligent Gamma Spectroscopic Probe,Dirad - Advanced ...
Publikations-Datenbank der Fraunhofer Wissenschaftler und Institute: Aufsätze, Studien, Forschungsberichte, Konferenzbeiträge, Tagungsbände, Patente und Gebrauchsmuster
When two communicating vessels are filled to a different height with liquid, the two levels equilibrate because the liquid can flow. We have looked for such equilibration with solid 4He. For crystals with no grain boundaries, we see no flow of mass, whereas for crystals containing several grain boundaries, wedetect a mass flow. Our results suggest that the transport of mass is due to the superfluidity of grain boundaries. ...
Rechargeable lithium-ion batteries power many of todays electric vehicles and nearly all portable electronic gadgets and power tools. These devices boast extreme reliability, but they depend on a flammable liquid organic electrolyte solution to shuttle ions between the electrodes, and those liquids pose a tiny but potentially serious fire hazard. So researchers have been searching for nonflammable solid electrolytes as replacements. Although some are nearing commercialization, scientists still do not know some basics, for example, how grain boundaries-interfaces between crystallites of the electrolyte-affect lithium-ion conduction, which controls battery current. So James A. Dawson and M. Saiful Islam of the University of Bath and coworkers carried out molecular dynamics simulations to study how readily lithium ions can hop across grain boundaries in polycrystalline Li3OCl, a promising solid electrolyte candidate. The team stresses that grain boundaries may enhance or impede ion conduction: The ...
One type of radiation therapy commonly used involves photons, packets of energy. X-rays were the first form of photon radiation to be used to treat cancer. Depending on the amount of energy they possess, the rays can be used to destroy cancer cells on the surface of an area, or penetrate to tissues deeper in the body. The higher the energy of the x-ray beam, the deeper the x-rays can go into the target tissue. Linear accelerators and betatrons are machines that produce x-rays of increasingly greater energy. The use of machines to focus radiation (such as x-rays) on a cancer site is called external beam radiotherapy. With modern radiation equipment, there is minimal scatter of x-ray energy outside the treatment beam. Scatter refers to the presence of radiation in the body outside the field of treatment. Imagine a beam of light from a flashlight projected on a wall. The visible beam of the light is well defined (equivalent to the radiation beam) with only a slight halo of light around the edges ...
On Friday I had my first appointment with the radiological oncologist, Dr Hughes. It was mostly to discuss the treatment. There will be 28 radiation treatments 5 days/week starting on Nov 10. Based on that, radiation will be complete on December 19th. Surgery will happen a week or so after that. It looks like the level of radiation and chemo drugs involved wont keep my from work or anything, it may just make me a little tired.. This Wednesday, Ill be spending the morning at Dr Hughes office getting simulated. That means a CT scan and a couple tatoos that will be used to align the radiation equipment for my daily doses starting on the 10th.. ...
CVD SILICON CARBIDFM Components for Semiconductor Processing Equipment Recognized as the premier choice for RTP/epi rings and susceptors and plasma etch chamber components, solid CVD SILICON CARBIDEM Components excel where high temperatures (>1500oq, ultra-high purity (>99.9995%) and chemical resistance are system requirements. The material contains no secondary phases at grain boundaries resulting in components with lower particle generation than other materials. In addition, these components can be cleaned in hot HF/HCI with minor degradation resulting in very low particle generation and longer life.. CVD SILICON CARBIDETM Material attributes:. ...
Light-and elevated temperature-induced degradation (LeTID) is a detrimental effect observed under operating conditions in p-Type multicrystalline silicon (mc-Si) solar cells. In this contribution, we employ synchrotron-based techniques to study the dissolution of precipitates due to different firing processes at grain boundaries in LeTID-Affected mc-Si. The synchrotron measurements show clear dissolution of collocated metal precipitates during firing. We compare our observations with degradation behavior in the same wafers. The experimental results are complemented with process simulations to provide insight into the change in bulk point defect concentration due to firing. Several studies have proposed that LeTID is caused by metal-rich precipitate dissolution during contact firing, and we find that the solubility and diffusivity are promising screening metrics to identify metals that are compatible with this hypothesis. While slower and less soluble elements (e.g., Fe and Cr) are not compatible ...
The study is aimed to understand atomic scale details of defect-boundary interactions, which are critical to develop radiation tolerant fuel cladding materials for harsher neutron environments. By means of molecular dynamics simulations, we addressed the key questions of (1) how defects are trapped by a grain boundary, (2) how defect are annihilated at a grain boundary, and (3) what are upper limits of radiation tolerance of boundary-engineered metals. The modeling is performed by using large-scale atomic/molecular massively parallel simulator (LAMMPS) code and pure Fe is selected as the model material. For mechanism of defect tapping towards a grain boundary, we find that, instead of the general consensus that the trapping is caused by biased defect diffusions due to relatively lower defect formation energies at a grain boundary, long range defect migration is realized by creation of chain like defects. A chain is induced by the stress field around a defect, and is formed by pushing its ...
Engineering grain boundaries (GBs) are effective in tuning the thermoelectric (TE) properties of TE materials, but the role of GB on mechanical properties, which is important for their commercial applications, remains unexplored. In this paper, we apply ab initio method to examine the ideal shear strength and failure mechanism of GBs in TE oxide BiCuSeO. We find that the ideal shear strength of the GB is much lower than that of the ideal single crystal. The atomic rearrangements accommodating the lattice and neighbor structure mismatch between different grains leads to the much weaker GB stiffness compared with grains. Failure of the GBs arises from either the distortion of the Cu-Se layers or the relative slip between Bi-O and Cu-Se layers. This work is crucial to illustrate the deformation of GBs, laying the basis for the development and design of mechanically robust polycrystalline TE materials. ...
Grain coarsening is one of the favourite topics for popular discussion for materials scientists (because you can begin your discussion with beer heads and also you can set up some nice experiments with bubble rafts). Here is a viewpoint piece in Physics on the statistical mechanics of grain boundaries: Thermodynamic arguments and a one-dimensional model…
with a purpose to make smooth grain obstacles and keep away from the segregation of Gd at the interface weve got introduced an digital conductor cobalt iron spinel (CFO), ensuing in a composite structure, said Kyle Brinkman, a professor at Clemson university and co-creator of the work. The CFO reacts with the excess Gd gift in the grain boundary of GDC to form a 3rd segment. It become located that this new segment may also serve as an exceptional oxygen ionic conductor. We in addition investigated the atomic microstructure around the grain boundary through a series of high decision characterization strategies and observed that Gd segregation within the grain boundary have been removed, main to dramatic development in the grain boundary oxygen ionic conductivity of GDC ...
A micromechanical model of creep induced grain boundary damage is proposed, which allows for the simulation of creep damage in a polycrystal with the finite element method. Grain boundary cavitation and sliding are considered via a micromechanically motivated cohesive zone model, while the grains creep following the slip system theory. The model has been calibrated with creep test data from pure Cu single crystals and a coarse-grained polycrystalline Cu-Sb alloy. The test data includes porosity measurements and estimates of grain boundary sliding. Finally, the model has been applied to Voronoi models of polycrystalline structures. In particular the influence of grain boundary sliding on the overall creep rate is demonstrated ...
Researchers have reported results correlating the flake merging angle with grain boundary (GBs) properties, and proven that increasing the merging angle of GBs drastically improves the flow of electrons.
In this work, we describe the use of the atom-probe tomography technique for studying the grain boundaries of the absorber layer in a...
Dynamic multileaf collimator intensity modulated radiation therapy is used to deliver intensity modulated beams on a collimator with the multiple leaves in motion. Research has shown that optimal leaf sequencing based on unidirectional movement of the collimator leaves is as MU efficient as bidirectional movement of these leaves. Efficient algorithms for segmental collimator beam delivery that completely eliminates areas of under dosages due to practical tongue-and-groove effects between adjacent leafs have also been developed. These methods result in 10% to 20% decrease in total MU as compared to field splitting techniques used in commercial planning systems. It also allows for the scheduling of the leaves of a multi-leaf collimator in order to optimize radiation therapy time, and minimize damage to surrounding healthy tissue. ...
Several treatment techniques exist can be used when treating lung cancer. Some common radiation treatment techniques are the following: VMAT, RapidArc, IGRT, IMRT, SRS, SBRT (or Radiosurgery).
Several treatment techniques exist can be used when treating head and neck cancers. Some common radiation treatment techniques are the following: VMAT, RapidArc, IGRT, IMRT, brachytherapy
Nainite, carbon, atom probe, partitioning, cementite, acicular, strength, atom probe tomography, ebsd, carbon, grain boundary, segregation, grain boundary, interface, heat treatment, EBSD, microstructure
Geng et al. claim that the GB expansion of the (GB0 4/4, GB2 4/4) case (1.2Å) is twice as large as that of the (GB1 4/4, GB2 4/4) case (0.6Å). Here, they may miscalculate the GB expansion as well as the binding energies. The S atoms enter the GB0 interstitial vacancies in the (GB0 4/4, GB2 4/4) case, whereas S substitutes for Ni at GB1 sites in the (GB1 4/4, GB2 4/4) case. The formula used to calculate the GB expansion [Supporting Online Material in (1)] cannot be used to compare the two cases that have different numbers of Ni layers; the discrepancy of the GB expansion (0.6Å) in the Geng et al. calculations may come from the difference in the number of Ni layers, as shown in Fig. 1. The Ni interlayer distance in the ,012, direction is 0.78Å, which agrees well with the difference.. As pointed out by Geng et al., the GB3 monolayer is greatly stabilized by adding the GB1 monolayer. As shown in Table 1(IV), the incremental binding energy of adding GB1 1/4 monolayer to the GB3 4/4 monolayer is ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
A method of continuous real-time monitoring and positioning of multi-leaf collimators during on and off radiation exposure conditions of radiation therapy to account for target motion relative to a radiation beam is provided. A prediction algorithm estimates future positions of a target relative to the radiation source. Target geometry and orientation are determined relative to the radiation source. Target, treatment plan, and leaf width data, and temporal interpolations of radiation doses are sent to the controller. Coordinates having an origin at an isocenter of the isocentric plane establish initial aperture end positions of the leaves that is provided to the controller, where motors to position the MLC midpoint aperture ends according to the position and target information. Each aperture end intersects a single point of a convolution of the target and the isocenter of the isocentric plane. Radiation source hold-conditions are provided according to predetermined undesirable operational and/or
A method of continuous real-time monitoring and positioning of multi-leaf collimators during on and off radiation exposure conditions of radiation therapy to account for target motion relative to a radiation beam is provided. A prediction algorithm estimates future positions of a target relative to the radiation source. Target geometry and orientation are determined relative to the radiation source. Target, treatment plan, and leaf width data, and temporal interpolations of radiation doses are sent to the controller. Coordinates having an origin at an isocenter of the isocentric plane establish initial aperture end positions of the leaves that is provided to the controller, where motors to position the MLC midpoint aperture ends according to the position and target information. Each aperture end intersects a single point of a convolution of the target and the isocenter of the isocentric plane. Radiation source hold-conditions are provided according to predetermined undesirable operational and/or
For the first time, using chromosome engineering of durum wheat, the underlying genetic determinants of a yield-improving segment from Thinopyrum ponticum (7AgL) were dissected. Three durum wheat-Th. ponticum near-isogenic recombinant lines (NIRLs), with distal portions of their 7AL arm (fractional lengths 0.77, 0.72, and 0.60) replaced by alien chromatin, were field-tested for two seasons under rainfed conditions. Yield traits and other agronomic characteristics of the main shoot and whole plant were measured. Loci for seed number per ear and per spikelet were detected in the proximal 7AgL segment (0.60-0.72). Loci determining considerable increases of flag leaf width and area, productive tiller number per plant, biomass per plant, and grain yield per plant were located in the distally adjacent 0.72-0.77 7AgL segment, while in the most distal portion (0.77-1.00) genetic effects on spikelet number per ear were identified. Contrary to previous reports, trials with the bread wheat T4 translocation ...
Panasonic debuts PX600 Viera high-definition plasma TVs A model in Panasonic’s new PX600 Viera series of high-definition widescreen plasma TVs Photo: Company, March 2006 The 50-inch TH-50PX600, 42-inch TH-42PX600 and 37-inch TH-37PX600 will be available in the Japan market on April 15, followed by the 58-inch 58PX600 on May 1, according to the company. "The Viera Link makes home-theater entertainment pure fun and enjoyable.
Consequently, a next-generation treatment technique can be warranted in the osimertinib era. in osimertinib-resistant lung tumors. Intro The finding of somatic mutations in epidermal development element receptor (mutations1C3. Nevertheless, lung tumors undoubtedly acquire level of resistance to 1st- or second-generation EGFR-TKIs around 12 weeks4C6. Therefore, it is vital to clarify the systems of level of resistance and establish related treatment strategies. Multiple research have exposed that T790M may be the most frequent system of level of resistance. To conquer the T790M mutation, third-generation (3rd-gen) EGFR-TKIs such as for example osimertinib and nazartinib have already been developed. Currently, osimertinib continues to be approved for individuals with lung tumors harboring T90M7 clinically. 3rd-gen EGFR-TKIs efficiently inhibit both resistant and delicate mutations (e.g., L858R and 15?bp DEL)8C10, while exhibiting much less level of sensitivity to wild-type EGFR and leading to much ...
Study Chapter 10 SNS Treatment Techniques flashcards from Joel Gieswein's class online, or in Brainscape's iPhone or Android app. ✓ Learn faster with spaced repetition.
There are three main calorie bombs that might be causing the problem. Think carefully about your horses diet: is he getting any of these? Pasture, grain/sweet feed, and legume (alfalfa) hay.. Start by looking at your hay; its pretty simple to switch from alfalfa to grass hay. If you can feed a more mature type (less soft and green, more stemmy), while still keeping an eye on the quality (fresh and free of weeds), this is the best starting point. Taking it one step further and feeding his hay out of a small-hole net will keep him occupied longer, reducing the incidence of gastric ulcers and behavior problems. Keep small meals coming, preferably three times per day.. Next, lets look at grain, more correctly termed concentrate in the horse-feeding world. This refers to a concentrated source of calories, which can include different grains, fats, and sometimes beet pulp. If your barn just goes down the line dumping a scoop of the same grain to every horse, you need to make sure he stops getting ...
Kelli and Georgia went with me and I was so glad to have Kellis opinion. She was so helpful….and Georgie was perfect.. We started at Grain and Thread. I was a great shop. They had a few things that could work…nothing that said BUY ME!! This time when I was shopping I wanted something that I was HAPPY with…not something that was a make do piece. Ive had enough make do pieces…Im 54 years old. I wanted something I WANTED.. Although nothing worked furniture wise, there were still lots of wonderful things there. The clothes were wonderful and reasonably priced. There were nice home dec type things there to. Ill definitely be back.. From there we went to the antique store on the corner. We walked in the door and saw this….. Kelli and I both looked at each other…Hmmm. I liked that it was narrow. The length was good.. ...
Samsungs piano-black LN-S3251D LCD combines high-styled looks with high-definition picture quality. The 32 screen delivers enough visual impact for a modest home theater, and the compact size and light weight make this an outstanding bedroom TV. The LN-S3251D is a good indicator of how fast LCD picture quality
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A phase-field model for the simulation of solidification and grain growth during an electron beam welding process is presented. With the simplifying assumptions, the macroscopic temperature field inside the welding sample is assumed to be quasi-stationary. Moreover, the principle of superposition is applied to derive the macroscopic temperature distribution. To use the temperature field as input in the simulations of the grain evolution, the analytical expression of the macroscopic temperature field, which is given as an indefinite integral, is approximated with a closed-form approach. ... mehrThe extension of the phase-field model, which incorporates the nucleation model, is applied to reconstitute the results of different solidification scenarios. Furthermore, the usage of temperature-dependent grain boundary mobility allows to simulate grain coarsening in the weld as well as in the heat-affected zone. The qualitative adjustment between the numerical, theoretical and real grain structures is ...
I develop a phenomenology of a particular model of disordered supersolidity. It is related to proposals that superflow occurs along defects-dislocations, grain boundaries, and amorphous regions-but...
Hello, my name is Anvar and I am PhD student at the University of Warwick. My PhD is being supervised by Dr. Florian Theil and Dr. Thomas Hudson, and I am currently studying the energies of small angle grain boundaries under a fully discrete dislocation model.. ...
M.L. Taheri, J. Sebastian, V. Radmilovic, N. Zaluzec, D. Seidman, E.A. Stach and A.D. Rollett, Studies of the Effect of Solute Segregation on the Anisotropy, Mobility and Chemistry of Grain Boundaries: Direct In-Situ Observations from the Meso- to the Atomic Scale, Acta Materialia, submitted (2007 ...
It covers the major parts of the neuroaxis, sympathetic trunk and larger peripheral nerves. The techniques can be used for treating a variety of clients. Manual therapy from a neurodynamic perspective is based on the nervous system being one continuous tissue that needs a certain amount of mobility and circulation to function optimally. To be able to normalize the
With rounded corners and smooth finishes, the Gendex™ GXS-700™ sensors comfortably fit the oral cavity. High-definition images having amazing clarity and detail that support diagnosis and treatment.
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Whats the best plasma available at the moment? im looking for something between 2k - 3.5k 48 & High-Definition, preferably a panasonic. Also im...
Site planning requirements is another factor to consider because installation of linear accelerator parts for radiation equipment requires important considerations such as room dimensions, power, local permits, water supply and future equipment technology.. The timeline for completing your project is critical for planning and executing milestones such as installation dates, equipment acceptance testing dates and going live with the linear accelerator parts. It is important to factor in some level of flexibility in your project timeline so as to account for unforeseen developments and challenges.. Your budget will determine the technology, manufacturer, and age of your equipment acquisition. A limited budget can influence you to go for refurbished linear accelerator parts for your radiation equipment. This also ensures available resources to effectively carry out other essential operations of your practice.. ...
To provide a semiconductor device having a function equivalent to that of IGFET, an activation layer is formed by a crystal silicon film crystallized by using a catalyst element helping promote crystallization and a heating treatment is carried out in an atmosphere including a halogen element by which the catalyst element is removed, the activation layer processed by such steps is constituted by a peculiar crystal structure and according to the crystal structure, a rate of incommensurate bonds in respect of all of bonds at grain boundaries is 5% or less (preferably, 3% or less).
In the safety case for the geological disposal of nuclear waste, the release of radioactivity from the repository is controlled by the dissolution of the spent fuel in groundwater. There remain several uncertainties associated with understanding spent fuel dissolution, including the contribution of energetically reactive surface sites to the dissolution rate. In this study, we investigate how surface features influence the dissolution rate of synthetic CeO2 and ThO2, spent nuclear fuel analogues that approximate as closely as possible the microstructure characteristics of fuel-grade UO2 but are not sensitive to changes in oxidation state of the cation. The morphology of grain boundaries (natural features) and surface facets (specimen preparation-induced features) was investigated during dissolution. The effects of surface polishing on dissolution rate were also investigated. We show that preferential dissolution occurs at grain boundaries, resulting in grain boundary decohesion and enhanced ...
TY - JOUR. T1 - The structure of grain boundaries in granite-origin ultramylonite studied by high-resolution electron microscopy. AU - Hiraga, T.. AU - Nagase, Toshiro. AU - Akizuki, M.. PY - 1999/9/1. Y1 - 1999/9/1. N2 - The structure of grain boundaries in a granite-origin ultramylonite, composed mainly of fine-grained feldspar and quartz, was studied by high-resolution electron microscopy (HREM). At most of the boundaries, not only between the same minerals but also between different minerals, lattice fringes in adjacent grains meet at the interface with no other appreciable phases. In these boundaries, some of the straight segments correspond to a low-index plane of one of the connected grains. Boundaries containing voids, with a spheroidal shape elongated along the boundaries, were observed only between quartz grains. It is suggested that these boundaries were formed by healing of microcracks. The structural width of major boundaries, deduced from lattice-fringe imaging, is less than about ...
M] Surface Science Vol.31 : Grain Boundaries and Interfaces : Proceedings of the International Conference on the Structure and Properties of Grain Boundaries and Interfaces, Yorktown Heights, New York 23-25 August, 1971 ...
In many alloy systems, hydrogen embrittlement under relatively high fugacity conditions occurs by intergranular fracture. One of these is the iron nickel alloy system which exhibits intergranular hydrogen related fracture when tested with a high supersaturation of solute hydrogen or while being cathodically charged with hydrogen. The results obtained on this alloy system indicate that the hydrogen embrittlement susceptibility decreases as the iron concentration of the alloy increased. These early measurements contained no information about the grain boundary chemistry and it is known that the effects of hydrogen are generally sensitive to the concentrations of other elements at grain boundaries. One particular element, sulphur, is known to increase the susceptibility of nickel alloys and fe alloys to hydrogen embrittlement although the mechanism of this increased susceptibility is not known. (JES)*HYDROGEN EMBRITTLEMENT
In its Glossary of Terms, Volume 13, Corrosion, p. 6 defines exfoliation as follows: Corrosion that proceeds laterally from the sites of initiation along planes parallel to the surface, generally at grain boundaries, forming corrosion products that force metal way from the body of the material, giving it a layered appearance. It also indicates that it is synonymous to lamellar corrosion. The Encyclopedia Britannica indicates that this term suggests a composition or arrangement in the form of a thin, flat layer or scale. Nothing in the Glossary restricts the term to aluminum. Under Materials Selection, p. 334, Greg Kobrin states that exfoliation affects primarily aluminum alloys, attack proceeding laterally from initiation sites on the surface and generally proceeding intergranularly along planes parallel to surface. Don Sprowls discusses evaluation of exfoliation on pp. 242-3, particularly as regards the ASTM tests (e.g., G34, G64, G66, G85, etc,). Under Temper Effects, p. 295, it is stated ...
Links between leaf morphology and temperature have been established at a range of ecological scales [1,2]. Narrower leaves can lose heat without evapotranspiration during hot, dry summers [3]. We proposed that an observed decrease in leaf width in Dodonaea viscosa subsp. angustissima was consistent with expectations from a changing climate based on a latitudinal cline [4].. Duncan [5] proposes a different interpretation by analysing leaf width data dating from before and after the onset of a significant warming trend separately. Duncan proposes the shift occurred before this warming trend and is not linked to temperature. Although this data split could be considered arbitrary, there is merit to the approach, in that a strong warming trend began from 1950. However, other analytical permutations may also be informative.. If temperature increases post-1950 have driven decreases in leaf width, we would expect to observe a shift between pre-1950 and more recent collections. We would also expect to ...
The fundamental mechanisms behind the generation of compressive stresses in polycrystalline thin films, the effects of pulsed deposition fluxes on the dynamics of the early growth stages as well as the generation of energetic Ar+ ions in high power impulse magnetron sputtering (HiPIMS) discharges has been studied in this thesis.. It was found that compressive film stresses in Mo films deposited using energetic vapor fluxes are correlated with high film densities while only a slight lattice expansion compared to relaxed Mo was found. This implies that the stress is caused by grain boundary densification and not defect creation in the grain bulk. The compressive stress magnitude should scale with the grain boundary length per unit area, or the inverse grain size, if the stress originates in the grain boundaries. This was found to be the case for dense Mo films confirming that the observed compressive stresses originate in the grain boundaries. Similarly to what has been suggested for conditions ...
Abstract: The results of investigations of magnetically driven grain boundary migration in high purity (99.995%) zinc bicrystals are presented. In-situ measurements were conducted by means of a specially designed and fabricated polarization microscopy probe. The migration of planar tilt grain boundaries with various misorientation angles in the range between 60° and 90° was studied. The absolute grain boundary mobility and its temperature dependence was measured in the regime between 330°C and 415°C and the corresponding migration activation parameters were determined. The results revealed that there is a pronounced misorientation dependence of grain boundary mobility in the investigated angular range. The migration activation enthalpy was found to vary between 1.18 eV and 2.15 eV. The obtained activation parameters comply with the compensation law, i.e. the migration activation enthalpy changes linearly with the logarithm of the pre-exponential factor ...
Nuclear DNA content (2C) is used as a new criterion to investigate nearly all species of the genus Nerine Herb. The species have the same chromosome number (2n = 2x = 22), with the exception of three
Effect of grain boundaries on carrier lifetime in chemical-vapor-deposited diamond film. Yoneda, Hitoki; Tokuyama, Kazutatsu; Tokuyaman, Kazutatsu; Yamazaki, Riichi; Ueda, Ken-ichi; Yamamoto, Hironori; Baba, Kazuhiro // Applied Physics Letters;9/4/2000, Vol. 77 Issue 10 Using the reflective measurements, the effect of grain boundaries on the lifetime of photogenerated carriers was investigated for chemical-vapor-deposited (CVD) diamond films. To investigate the effect of grain boundaries on the carrier dynamics, photons having energy lower than the band gap... ...
In many practical applications, creep damage is the limiting factor of a component s lifetime. A micromechanical model of creep induced grain boundary damage is proposed, which allows for the simulation of creep damage in a polycrystal within the framework of finite element analysis. The model considers grain boundary cavitation and sliding according to a micromechanically motivated cohesive zone model while creep deformation of the grains is described following the slip system theory. The model can be applied to idealised polycrystalline structures, such as a Voronoi tessellation or, like demonstrated here, to real grain structures of miniature creep specimens. Creep tests with pure Cu single crystals and with a coarse-grained polycrystalline Cu-1 wt.% Sb alloy at 823 K have been performed and used to calibrate the polycrystal model. The grain structure of the polycrystalline Cu Sb specimens has been revealed by the EBSD method. Extensive grain boundary sliding and cavitation has been observed in the
TY - JOUR. T1 - Simulations of intergranular fracture in nanocrystalline molybdenum. AU - Frederiksen, Søren Lund. AU - Jacobsen, Karsten Wedel. AU - Schiøtz, Jakob. PY - 2004. Y1 - 2004. N2 - Using molecular dynamics simulations we investigate the plastic deformation of nanocrystalline molybdenum with a grain size of 12 nm at high strain rates. The simulations are performed with an interatomic potential which is obtained through matching of atomic forces to a database generated with density-functional calculations. The simulations show the plastic deformation to involve both grain boundary processes and dislocation migration which in some cases lead to twin boundary formation. A large component of the strain is accommodated through the formation of cracks in the grain boundaries. This behavior is very different from what has been seen earlier in simulations of fee metals where grain boundary sliding is the dominant mechanism for very small grain sizes. (C) 2004 Acta Materialia Inc. Published ...
If you have a question about this talk, please contact Ian Farnan.. Joint with Materials Sciences. There is renewed interest in the properties of hetero- and homophase boundaries in the perovskite oxide SrTiO3 because of this materials possible application in all-oxide electronics, as a high-k dielectric, and in resistive-switching devices. In this talk I focus on the interplay between point defects and interfaces (grain boundaries and surfaces) in acceptor-doped SrTiO3. Experimental results obtained for various symmetrical low-angle [001] tilt grain boundaries are presented. The results are examined within a thermodynamic framework that allows the properties of grain boundaries in acceptor-doped SrTiO3 to be predicted. The aim is to derive relationships between the crystallographic structure of an interface and its transport properties. The second part of the talk concerns non-uniform defect distributions at the (100) surface of SrTiO3. A method for probing such non-uniform defect ...
TY - JOUR. T1 - Linear bubble model of abnormal grain growth. AU - Mullins, W. W.. AU - Viñals, Jorge. PY - 2002/6/28. Y1 - 2002/6/28. N2 - A linear bubble model of grain growth is introduced to study the conditions under which an isolated grain can grow to a size much larger than the surrounding matrix average (abnormal growth). We first consider the case of bubbles of two different types such that the permeability of links joining unlike bubbles is larger than that of like bubbles (a simple model of grain boundary anisotropy). Stable abnormal growth is found both by mean field analysis and direct numerical solution. We next study the role of grain boundary pinning (e.g., due to impurities or precipitate phases) by introducing a linear bubble model that includes lower and upper thresholds in the driving force for bubble growth. The link permeability is assumed finite for driving forces above the upper threshold, zero below the lower threshold, and hysteretic in between. Abnormal growth is also ...
Copyright © 1991 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ...
Introduction. Grain boundaries (GB) represent an important class of two-dimensional extended defects and macroscopic strength of polycrystalline materials depends strongly on GB cohesion. It was found that the impurities in ppm concentration can drastically change material properties. For example, in magnetic materials they can significantly change magnetic moments in the GB region. Intergranular embrittlement which is usually associated with segregation of impurities on the GB can result in a dramatic reduction of the ductility and strength. Here we present an ab initio study of $\Sigma$5(210) grain boundary in Ni$_3$Fe compound with two different interface stoichiometries, $\Sigma5(210)^{\mathrm{Fe,Ni}}$ with both Fe and Ni atoms at the GB and $\Sigma5(210)^{\mathrm{Ni,Ni}}$ with Ni atoms only. We consider both clean GB and the GB with segregated Al and Si.. Summary. Our calculations show that the $\Sigma5(210)^{\mathrm{Fe,Ni}}$ has the GB energy of 1.34 J/m$^2$ and an additional volume per ...
Gadolinium, yttrium and samarium-doped barium cerate pressed pellets were submitted to flash sintering experiments isothermally in the temperature range 800-1300oC under 200 V cm-1 electric field. The pellets were positioned inside a dilatometer furnace with Pt-Ir electrodes connected either to a power supply or to an impedance analyzer to evaluate the bulk and the grain boundary contributions to the electrical resistivity. Near full density was achieved in the sintered samples. The combined results of dilatometry and impedance measurements in conventionally and flash sintered specimens show substantial improvement of the electrical conductivity. Joule heating is assumed to be the primary effect for sintering. Improved grain-to-grain contact and the removal of depleted chemical species due to Joule heating at the space charge region are proposed, respectively, as the reasons for the decrease of the grain boundary component in the impedance diagrams and the improvement of the bulk electrical ...
A method of manufacturing a semiconductor device comprises, in patterning of a conductive film having a grain boundary on a very thin dielectric film, a first etching step of carrying out anisotropic etching until most of the conductive film in a flat portion disappears, and a second etching step of increasing a selective ratio to the dielectric film to etch the conductive film in an unnecessary portion such that a thickness of the dielectric film provided under the grain boundary can be held to prevent oxidation species from reaching an interface with a substrate after the first etching step.
Intermetallic compounds are generally brittle at room temperature and have high melting points. Cleavage or intergranular fracture modes are typical of intermetallics due to limited independent slip systems required for plastic deformation. However, there are some examples of intermetallics with ductile fracture modes such as Nb-15Al-40Ti. Other intermetallics can exhibit improved ductility by alloying with other elements to increase grain boundary cohesion. Alloying of other materials such as boron to improve grain boundary cohesion can improve ductility in many intermetallics.[8] They often offer a compromise between ceramic and metallic properties when hardness and/or resistance to high temperatures is important enough to sacrifice some toughness and ease of processing. They can also display desirable magnetic, superconducting and chemical properties, due to their strong internal order and mixed (metallic and covalent/ionic) bonding, respectively. Intermetallics have given rise to various ...
17. Campylopus tallulensis Sullivant & Lesquereux, Musci Bor.-Amer. ed. 2. 17. 1865. Plants to 5 cm, in tufts, yellowish green, rarely green. Stems slender, not or densely reddish tomentose, evenly foliate. Leaves about 5 mm, erect-spreading, lanceolate, narrowed to a straight, serrate tip; alar cells hardly differentiated, forming hyaline or reddish auricles; basal laminal cells hyaline, thin-walled, rectangular, often forming a V-shaped area; distal laminal cells short-rectangular, incrassate; costa filling half of the leaf width, shortly excurrent in a concolorous tip, in transverse section showing large adaxial hyalocysts occupying 1/2 of the thickness of the leaf, and abaxial groups of stereids, abaxially ridged. Specialized asexual reproduction by deciduous leaves or stem tips. Sporophytes not known.. Acidic rocks (granite, sandstone), exposed boulders, rarely on soil in open woods; 100-600 m; Ala., Ariz., Ark., Del., Ga., Ill., La., Miss., N.C., Ohio, S.C., Tenn., Va., Wyo.; Mexico; ...
Wake Forest Baptist has the largest reported, single-center experience with cytoreductive surgery and HIPEC and analysis of 20 years worth of patient data shows that outcomes have clearly improved for patients undergoing this treatment technique.
Musculoskeletal oncology is constantly evolving with varied treatment techniques applicable to many subspecialties. The providers, while focusing on their specialty, must also be aware of new and evolving technologies and treatment techniques in subspecialties other than their own. The conference is intended to enhance the overall fund of knowledge required for these providers to treat patients in all subspecialties and to inform their colleagues on the availability and quality delivery of these technologies. With such emerging technologies, treatment techniques and clinical research trials, it is imperative that providers are aware of the best options for the patients they may encounter ...
Wireline formation microelectrical imaging has been used for many decades to characterize reservoirs. The geological interpretation of image data is mainly used for structural analysis, fracture characterization, porosity analysis, heterogeneity analysis, rock typing, and facies classification. In addition, formation microelectrical images are commonly needed for complex reservoirs to help with the selection of wireline formation tester straddle packer locations. The quality of the data acquired using conventional formation microelectrical imaging tools may be degraded in highly resistive formations even with conductive mud because of the high noise-to-signal ratio, which can lead to fuzzy images with very few geological features visible. Phase shift, which is common in resistive formations, can result in reversed images, reversed contrast, and pad/flap mismatch, which can render the data unusable. A new tool for microelectrical imaging presents a solution to this problem by obtaining high-definition,
Sintering in practice is the control of both densification and grain growth. Densification is the act of reducing porosity in a sample, thereby making it more dense. Grain growth is the process of grain boundary motion and Ostwald ripening to increase the average grain size. Many properties (mechanical strength, electrical breakdown strength, etc.) benefit from both a high relative density and a small grain size. Therefore, being able to control these properties during processing is of high technical importance. Since densification of powders requires high temperatures, grain growth naturally occurs during sintering. Reduction of this process is key for many engineering ceramics. Under certain conditions of chemistry and orientation, some grains may grow rapidly at the expense of their neighbours during sintering. This phenomenon, known as Abnormal grain growth, or AGG results in a bimodal grain size distribution which has consequences on the mechanical performance of the sintered object. For ...
The physical properties of polycrystalline ceramic materials are closely related to their microstructure. The influence of the microstructure on the electrical performance of a material is especially straightforward in the case of the exceptional current‐voltage nonlinearity of ZnO‐based varistor ceramics, which is closely related to the ZnO grain size: a coarse‐grained microstructure results in a low breakdown voltage for the ceramics, while a fine‐grained microstructure is required for a high breakdown voltage. ZnO‐based varistor ceramic is obtained by the addition of small amounts of varistor dopants, such as oxides of Bi, Sb, Sn, Ti, Co, Mn, Ni, Cr and Al to ZnO. Each of these dopants has a specific influence on the grain growth and microstructure development, which can be defined in terms of the compliance with the following discriminators: formation of the liquid phase, formation of the solid particles of the secondary phase at the grain boundaries, degree of dopants solubility ...
Monte Calro simulations on the basis of the Potts model have been carried out to study normal grain growth in two dimensions. A microstructure of a polycrystalline aggregate can be represented by means of mapping onto a discrete lattice of which site is assigned an orientation number from 1 to ,i,Q,/i,. The following three lattice models were used in this simulation: triangular lattice (with first nearest neighbor site interactions), square lattice I (with first nearest neighbor site interactions) and square lattice II (with first and second nearest neighbor site interactions). The simulations were performed under constant temperature conditions (0≤,i,T,/i,,,i,T,sub,c,/sub,,/i,) quenched from an initial high temperature (,i,T,/i,»,i,T,sub,c,/sub,,/i,) state. Obtained microstructures are evolved keeping asimilar form of a grain boundary network. The microstructures produced especially on the triangular lattice model are in good correspondence with those in cross-sections of annealed metals and ...
An international team of researchers led by ANSTO has found that cold-rolling increases the susceptibility of materials to molten salt corrosion by an increase in grain boundary length, and other microstructural defects, which typically contribute to material strengthening.
Garnet-type lithium solid electrolytes have a general formula of Li5La3M2O12 where M can be Ta or Nb. These were first reported in 2005[8] and have been intensively studied in recent years. The most attractive property of this class of crystalline solid electrolyte is its excellent chemical stability against lithium metal and also against moisture, in addition to its high ionic conductivity. These materials can be handled in a dry room. An example of the Garnet-type solid electrolyte is Li6BaLa2Ta2O12, which displays a room temperature conductivity of 4 x 10-5 S/cm and a low grain boundary resistance.[9] When the Garnet-type solid electrolyte Li5La3M2O12 was partially substituted at the M site by Y or In, conductivity was further improved. For example, the composition Li5.5La3Nb1.75In0.25O12 showed an enhanced conductivity of 1.8 x 10-4 S/cm at 50 °C with a low activation energy of 49.2 kJ/mol.[10] Another composition, Li6.5La3Nb1.25Y0.75O12, showed a high conductivity of 2.7 x 10-4 S/cm at 25 ...
They do not quite fit together perfectly, says Li, which produces strain at the joints in the same way as tiles that dont align. In proximity to a grain boundary where strain exists, the electronic properties on the Bi2Se3 surface are modified. In-plane pulling protects the flow of electrons because the bonds are strong, says Li. Conversely, in-plane compression increases the separation of the quintuple layers, destroying the surface states. Unraveling the behaviors of TIs is important because its a promising material for spintronics, an emerging field of nanoscale electronics that involves the manipulation of the electron spin as well as the charge. By using the orientation of the electron spin, data transfer can be quicker and computing storage capacity increased. TIs would work well in spintronics, says Li, because the spin and velocity of their surface electrons is locked in at right angles. But first, scientist must find ways to manipulate their behaviors - even to create a simple ...
Researchers at Pennsylvania State University (University Park, Pa.) have theorized a method for controlling the grain boundaries of 2-D materials, areas where clusters of atoms meet other clusters on a substrate, which would give scientists greater influence over the properties of the materials that they are creating.
REDRAY is the first set-top 4K cinema player, providing the ideal solution for large-scale signs and displays in commercial applications.
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উপরে প্রদর্শিত ওজন ১০০% সঠিক নয়। এটা আনুমানিক ওজন, সঠিক ওজন কম কিংবা বেশি হতে পারে। প্রোডাক্ট বাংলাদেশে আসার পর প্রকৃত ওজন অনুযায়ী শিপিং চার্জ নির্ধারণ করা হবে ...
Tinnitus Clinicians can join Tinnitus Tunes and then freely use the tinnitus counselling content to complement their own tinnitus counselling treatment techniques.
The Consumer Electronics Association has announced updated core characteristics for ultra high-definition TVs, monitors and projectors for the home.
Hisense and Metalink Ltd. today announced their collaboration to offer innovative and cost-effective solutions for delivering high-definition (HD) multimedia over wireless ...
Kronoart - new generation of high-definition architectural facades. A collection of high-pressure structural laminates providing endless design possibilities.