6,348 research outputs found
Horizontal travelling heater method growth of Hg1−xCdxTe with crucible rotation
No full textA horizontal travelling heater method (THM) for growing cylindrical cyrstals from a partially filled solution zone has been investigated for the first time. By applying ampoule rotation, the whole cross section of the crystal is successively brought into contact with the liquid solution, which is effectively stirred by forced convection. This approach was used to grow single-crystalline Hg1−xCdxTe ingots from a Te-rich solution zone. The structural perfection and metallurgical homogeneity are equivalent to vertically-grown THM material
Growth of Tl doped PbTe single crystals by the travelling heater method
No full textSingle crystals of Tl doped PbTe were grown using the travelling heater method (THM) and the electrical properties were evaluated at 77 K and found to be p-type
Structural perfection of Hg1−xCdxTe Grown by THM
No full textThe defect structure of single crystals of Hg1-xCdxTe grown by the travelling heater method (THM) has been investigated using X-ray double crystal topography and a chemical etching technique. The structural perfection is found to depend on the ratio of growth and solidus temperature Tg/Ts
Crystal growth of PbTe and (Pb, Sn)Te by the bridgman method and by THM
No full textSynthesis and growth of PbTe and (Pb, Sn)Te single crystals by the Bridgman method and by the Travelling Heater Method (THM) from Te-rich solutions are described. It is to be seen from comparative investigations that seeded THM growth reproducibly provides oriented single-crystalline ingots free of low-angle grain boundaries and with etch pit densities of 8-12 × 104 cm-2. All the materials were p-type with carrier concentrations from 1 to 2 × 1018 cm-3
Introduction to thermo-hydro-mechanical (THM) wood processing
No full textWood is the ultimate renewable material. It possesses qualities that have made it a material of choice for millennia, these qualities further enhanced by its recognised carbon sequestration. However, as a biological material it suffers the same fate as any natural material, namely degradation. There are ways in which wood can be enhanced, including eco-friendly methods. One of the emerging eco-friendly methods is the combined use of temperature, moisture and mechanical action – so-called Thermo-Hydro-Mechanical (THM) treatments. THM processing can improve the intrinsic properties of wood, to produce new materials and to acquire a form and functionality desired by engineers without changing its eco-friendly characteristics. There are numerous THM processing techniques and the number of these processes is growing continuously. THM processing can be divided into two major categories; Thermo-Hydral treatments (TH) and Thermo-Hydro-Mechanical treatments (THM). TH is usually used to enhance wood properties, and is of importance in increasing stress relaxation during drying under high temperature, in the formation of wood-based composites or veneer products and in the artificial ageing of wood. THM on the other hand, is employed in the producing of new materials by densification, shaping by moulding, welding of wood by friction, embossment, bending of wood, wood fusion, and chip-less manufacturing. During THM treatment, wood undergoes large deformation, stress relaxation and chemical degradation, but with strong shape memory depending on parameters like temperature, moisture content, applied forces, processing time and the type of wood. Several TH and THM processes have recently been developed in Europe, Japan, the USA and Canada, but only some of them have been scaled-up industrially. However, to overcome the problems associated with TH/THM wood during processing at the laboratory scale, during scale up and controlling the end use properties, a detailed knowledge of these phenomena becomes important. This requires a close collaboration between experts in wood chemistry, wood mechanics and material science from both academia and from industry. With this report we would like to give a brief state-of-the-art of the important field of THM-processing. The aim of this work has not been to cover the complete field of THM-processing, just give an introduction
Measurement of Trihalomethanes (THM) in Drinking Water with an Automatic THM Analyzer
No full textFor waterworks the most fundamental subject is to maintain the safety of drinking water. It has become important every year to monitor the concentrations of trihalomethanes (THM). We developed a new automatic THM analyzer based on fluorometry with membrane separation, and investigated a correlation between the gas Chromatographic method and our THM analyzing method on drinking waters at 10 cities in Japan. The investigation resulted in good correlation (r=0.9807) between both methods. Good results were obtained when continuous measurements of THM in drinking water were performed by the analyzer. Consequently, it was found that the present analyzer could measure THM in drinking waters simply, rapidly, with good precision and could be applied to continuous monitoring of THM.</jats:p
Introduction to thermo-hydro-mechanical (THM) wood processing
No full textWood is the ultimate renewable material. It possesses qualities that have made it a material of choice for millennia, these qualities further enhanced by its recognised carbon sequestration. However, as a biological material it suffers the same fate as any natural material, namely degradation. There are ways in which wood can be enhanced, including eco-friendly methods. One of the emerging eco-friendly methods is the combined use of temperature, moisture and mechanical action – so-called Thermo-Hydro-Mechanical (THM) treatments. THM processing can improve the intrinsic properties of wood, to produce new materials and to acquire a form and functionality desired by engineers without changing its eco-friendly characteristics. There are numerous THM processing techniques and the number of these processes is growing continuously. THM processing can be divided into two major categories; Thermo-Hydral treatments (TH) and Thermo-Hydro-Mechanical treatments (THM). TH is usually used to enhance wood properties, and is of importance in increasing stress relaxation during drying under high temperature, in the formation of wood-based composites or veneer products and in the artificial ageing of wood. THM on the other hand, is employed in the producing of new materials by densification, shaping by moulding, welding of wood by friction, embossment, bending of wood, wood fusion, and chip-less manufacturing. During THM treatment, wood undergoes large deformation, stress relaxation and chemical degradation, but with strong shape memory depending on parameters like temperature, moisture content, applied forces, processing time and the type of wood. Several TH and THM processes have recently been developed in Europe, Japan, the USA and Canada, but only some of them have been scaled-up industrially. However, to overcome the problems associated with TH/THM wood during processing at the laboratory scale, during scale up and controlling the end use properties, a detailed knowledge of these phenomena becomes important. This requires a close collaboration between experts in wood chemistry, wood mechanics and material science from both academia and from industry. With this report we would like to give a brief state-of-the-art of the important field of THM-processing. The aim of this work has not been to cover the complete field of THM-processing, just give an introduction
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Drift Scale THM Model
No full textThis model report documents the drift scale coupled thermal-hydrological-mechanical (THM) processes model development and presents simulations of the THM behavior in fractured rock close to emplacement drifts. The modeling and analyses are used to evaluate the impact of THM processes on permeability and flow in the near-field of the emplacement drifts. The results from this report are used to assess the importance of THM processes on seepage and support in the model reports ''Seepage Model for PA Including Drift Collapse'' and ''Abstraction of Drift Seepage'', and to support arguments for exclusion of features, events, and processes (FEPs) in the analysis reports ''Features, Events, and Processes in Unsaturated Zone Flow and Transport and Features, Events, and Processes: Disruptive Events''. The total system performance assessment (TSPA) calculations do not use any output from this report. Specifically, the coupled THM process model is applied to simulate the impact of THM processes on hydrologic properties (permeability and capillary strength) and flow in the near-field rock around a heat-releasing emplacement drift. The heat generated by the decay of radioactive waste results in elevated rock temperatures for thousands of years after waste emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, resulting in water redistribution and altered flow paths. These temperatures will also cause thermal expansion of the rock, with the potential of opening or closing fractures and thus changing fracture permeability in the near-field. Understanding the THM coupled processes is important for the performance of the repository because the thermally induced permeability changes potentially effect the magnitude and spatial distribution of percolation flux in the vicinity of the drift, and hence the seepage of water into the drift. This is important because a sufficient amount of water must be available within a drift to transport any exposed radionuclides out of the drift to the groundwater below, and eventually to people within the accessible environment. Absent sufficient water, radionuclides cannot be transported and there would be no significant health effect on people, even if radioactive waste containers were damaged or corroded to such an extent that radionuclides were exposed to water
Introduction to thermo-hydro-mechanical (THM) wood processing [Elektronisk resurs]
No full textWood is the ultimate renewable material. It possesses qualities that have made it a material of choice for millennia, these qualities further enhanced by its recognised carbon sequestration. However, as a biological material it suffers the same fate as any natural material, namely degradation. There are ways in which wood can be enhanced, including eco-friendly methods. One of the emerging eco-friendly methods is the combined use of temperature, moisture and mechanical action – so-called Thermo-Hydro-Mechanical (THM) treatments.THM processing can improve the intrinsic properties of wood, to produce new materials and to acquire a form and functionality desired by engineers without changing its eco-friendly characteristics. There are numerous THM processing techniques and the number of these processes is growing continuously.THM processing can be divided into two major categories; Thermo-Hydral treatments (TH) and Thermo-Hydro-Mechanical treatments (THM). TH is usually used to enhance wood properties, and is of importance in increasing stress relaxation during drying under high temperature, in the formation of wood-based composites or veneer products and in the artificial ageing of wood. THM on the other hand, is employed in the producing of new materials by densification, shaping by moulding, welding of wood by friction, embossment, bending of wood, wood fusion, and chip-less manufacturing. During THM treatment, wood undergoes large deformation, stress relaxation and chemical degradation, but with strong shape memory depending on parameters like temperature, moisture content, applied forces, processing time and the type of wood. Several TH and THM processes have recently been developed in Europe, Japan, the USA and Canada, but only some of them have been scaled-up industrially. However, to overcome the problems associated with TH/THM wood during processing at the laboratory scale, during scale up and controlling the end use properties, a detailed knowledge of these phenomena becomes important. This requires a close collaboration between experts in wood chemistry, wood mechanics and material science from both academia and from industry.With this report we would like to give a brief state-of-the-art of the important field of THM-processing. The aim of this work has not been to cover the complete field of THM-processing, just give an introduction.</p
Fully coupled THM behaviour of argillaceous rocks subject to excavation and thermal loading
No full textThis study analyses the coupled Thermo-Hydro-Mechanical (THM) response of argillaceous rocks in high-temperature settings. The changes in the damage zone due to underground excavation and subsequent thermal loading caused by the heat emitted by the High-Level Waste (HLW) package have been examined. For this purpose, a fully coupled THM formulation has been used that includes a stress update algorithm, implemented in CODE_BRIGHT, to cater for an anisotropic porous medium using Biot’s effective stress. An advanced Hyperbolic Mohr-Coulomb elasto-viscoplastic model with damage and nonlocal formulation has been used to simulate the mechanical behaviour of the argillaceous rock. The generalized Darcy’s law and Fourier’s law have been adopted for the description of liquid flow and heat conduction, respectively. Anisotropy of stiffness, strength, permeability and thermal conductivity have been considered. It has also been assumed that permeability depends on the accumulated viscoplastic strains. Fully coupled THM analyses have been conducted to investigate the evolution of temperature, pore water pressure and damaged zones. The thermally-induced pore pressure rise is identified as a key mechanism in the development and evolution of the damaged zone. The analyses reported provide a better understanding of the THM response of HLW disposal schemes in argillaceous rocks under high temperatures.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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