Energy Technology Data Exchange (ETDEWEB)

The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the ...

Energy Technology Data Exchange (ETDEWEB)

An experimental technique has been developed to examine the interaction between deformation and the exposure of certain high temperature structural alloys to oxidizing molten salt environments. The experimental program involved performing a series of long-term tensile tests over a wide range of strain rates. Fracture strain reduction in area and ultimate strength (UTS) were monitored as parameters indicative of an alloy's susceptibility to environmental degradation. For Incoloy Alloy 800 tested at 600/sup 0/C in the salt medium and at initial strain rates between 2 x 10/sup -7/ sec/sup -1/ and 1 x 10/sup -5/ sec/sup -/1 no appreciable loss of ductility, as measured by reduction in area, was observed relative to control specimens tested in air at the same temperature and strain rates. Similarly, fracture strain and UTS were essentially unaffected by exposure to the oxidizing environment. The structure of the oxide film formed by contact ...

International Nuclear Information System (INIS)

Uranium dendrites which were deposited at a solid cathode of an electrorefiner contained a certain amount of salts. These salts should be removed for the recovery of pure metal using a cathode processor. In the uranium deposits from the electrorefining process, there are actinide chlorides and rare earth chlorides in addition to uranium chloride in the LiCl-KCl eutectic salt. The evaporation behaviors of the actinides and rare earth chlorides in the salts should be investigated for the removal of salts in the deposits. Experiments on the salt evaporation of rare earth chlorides in a LiCl-KCl eutectic salt were carried out. Though the vapor pressures of the rare earth chlorides were lower than those of the LiCl and KCl, the rare earth chlorides were co-evaporized with the LiCl-KCl eutectic salt. The ...

Science.gov (United States)

The corrosion behavior of Ta, Ti, and Zr in inorganic acids, bases, chlorides and miscellaneous salts, waters and gases, and organic acids and miscellaneous organic chemicals is summarized. (W.L.H)

International Nuclear Information System (INIS)

In the electrorefining step of the pyrochemical process, actinide ions dissolved in the LiCl-KCl eutectic salt are recovered as pure actinide metals at a cathode for a re-use as a nuclear fuel from the aspect of its nonproliferation of the nuclear fuel cycles. The lanthanide species dissolved in the LiCl-KCl eutectic salt play an important role in an effective metal purification during the electrorefining step, so it is necessary to understand the chemical and physical behaviors of lanthanides in molten salt. The in situ spectroscopic measurement system and studies according to temperature changes are essential for better understandable information. To our knowledge, the absorption studies of lanthanides at high temperatures have been reported before, but the fluorescence studies of those at high temperature are not reported yet. We will discuss here the fluorescence behaviors of ...

International Nuclear Information System (INIS)

The electrochemical/spectroscopic integrated measurement system was designed and set up for spectro-electrochemical measurements of lanthanide and actinide ions in high temperature molten salt media. A compact electrochemical cell and electrode system was also developed for the minimization of reactants, and consequently minimization of radioactive waste generation. By applying these equipment, oxidation and reduction behavior of lanthanide and actinide ions in molten salt media have been made. Also, thermodynamic parameter values are determined by interpreting the results obtained from electrochemical measurements. Several lanthanide ions exhibited fluorescence properties in molten salt. Also, UV-VIS measurement provided the detailed information regarding the oxidation states of lanthanide and actinide ions in high temperature molten salt media

International Nuclear Information System (INIS)

Pyrochemical processing of nuclear fuels using molten salts has attracted much attention because of its potential to be applied for a future spent nuclear fuel management. In the pyrochemical processing, there are a number of steps to electro-refine and electro-win each element of lanthanides and actinides, commonly called trans-uranic elements (TRU). In order to materialize the pyrochemical processing in the nuclear power plant environments, qualitatively and quantitatively monitoring of each elements is necessary. Thus, we have undertaken to develop an on-line observing system of the TRU in LiCl-KCl molten salt media by using electrochemical and spectroscopic methods. In this work, the electrochemical and spectroscopic behaviors of europium as a proxy material for TRU were investigated simultaneously in the LiCl-KCl molten salt

International Nuclear Information System (INIS)

The mechanism of the salt concentration increase in pits and crevices formed in a steam generator due to its imperfect manufacture or to its design features is described. The probability of corrosion can be reduced by choosing a suitable steel and by securing low concentrations of salts (chlorides in particular) and corrosion products in the feedwater. Attention is paid to the distribution of salts in the water-steam circuit and to the conditions of erosion corrosion as the principal source of corrosion products in feedwater. Experience with the suppression of erosion corrosion at nuclear power plants abroad is described. (E.J.).

UK PubMed Central (United Kingdom)

Female mammals are particularly sensitive to changes in food availability. The mechanisms that affect sexual behavior and food intake are closely related to one another; chief among the mechanisms...Full Text Available

CERN Document Server

We review a new theoretical approach to the kinetics of surfactant adsorption at fluid-fluid interfaces. It yields a more complete description of the kinetics both in the aqueous solution and at the interface, deriving all equations from a free-energy functional. It also provides a general method to calculate dynamic surface tensions. For non-ionic surfactants the results coincide with previous models. Common non-ionic surfactants are shown to undergo diffusion-limited adsorption, in agreement with experiments. Strong electrostatic interactions in salt-free ionic surfactant solutions are found to lead to kinetically limited adsorption. In this case the theory accounts for unusual experimental results which could not be understood using previous approaches. Added salt screens the electrostatic interactions and makes the ionic surfactant adsorption similar to the non-ionic case. The departure from the non-ionic behavior as ...

British Library Electronic Table of Contents (United Kingdom)

The age hardening behavior of Al-4.5%Cu alloy composite reinforced with zircon sand particulates and produced by stir casting route has been investigated in different quenching media viz, water, oil, and salt brine solution (7wt%). Optical microscopy of the as cast alloy composite indicates that the matrix of the composite has the cellular structure. Copper rich CuAl2 precipitates have been found near particle matrix interface. The results of ageing demonstrate that the microhardness of age hardenable Al-Cu based alloy composites depend on the quenching medium in which they are heat treated. Salt brine quenching is faster as compared to water and oil, even if higher strength is obtained but cannot be used for complex shapes and thin sections where oil quenching is the alternative due to mi...

Energy Technology Data Exchange (ETDEWEB)

Decontamination and decommission activities related to the Molten Salt Reactor Experiment (MSRE) involve the trapping and recovery of radiolitically generated uranium hexafluoride and fluorine. Although fission product radiolysis was known to generate F{sub 2}, the formation of UF{sub 6} and its transport from the fuel salt was unexpected. Some of these gaseous radiolysis products have been moving through the gas piping to a charcoal bed since the reactor was shut down in 1969. Current and planned remediation and clean-up activities involve the trapping of the gaseous products, deactivation and treatment of the activated charcoal bed, stabilization and reconditioning of the fuel salt, and recovery of the uranium. The chemical aspects of these processes, including radiolytic generation mechanisms, reactions between uranium hexafluoride and fluorine and trapping materials such as activated charcoal, ...

UK PubMed Central (United Kingdom)

Psychopathic individuals are generally unresponsive to motivational and emotional cues that facilitate behavioral regulation. A putative mechanism for this deficiency is Gray’s (1971)...Full Text Available

UK PubMed Central (United Kingdom)

The interaction between two metals, which can be either synergistic or antagonistic, implies that the behavior of one is changed by the presence of the other. Possible mechanisms of these interactions,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundOsseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility...Full Text Available

UK PubMed Central (United Kingdom)

In all mammals, tissue inflammation leads to pain and behavioral sensitization to thermal and mechanical stimuli called hyperalgesia. We studied pain mechanisms in the African naked mole-rat, an unusual...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The kinetics of the solubilization of lauric acid, palmitic acid, stearic acid, and monopalmitin have been studied in detergent solutions as a function of concentration, temperature, and fluid flow. The detergents used were sodium dodecyl sulfate (an anionic surfactant), decyltrimethylammonium bromide (a cationic surfactant), sodium taurocholate (a trihydroxy bile salt), sodium taurodeoxycholate (a dihydroxy bile salt), and triton X-100 (a nonionic surfactant). At low temperature, solubilization can be described by a five-step mechanism is which micelle desorption and diffusion are rate controlling. At temperatures above the fatty acid penetration temperature, solubilization is governed by formation of a liquid crystalline phase at the fatty acid-detergent solution interface.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim is to show the influence of the parameters on the microstructure and texture and how this could affect the anisotropy in the rolled sheets. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

The electrochemical behavior of lanthanide oxides in molten alkaline chloride media is of great concern in pyrochemical processes for advanced nuclear fuel cycle. We have studied the solubilities of various lanthanide oxides in LiCl-KCl eutectic melt. In general, lanthanide oxides appeared to be insoluble/sparingly soluble in LiCl-KCl eutectic at 723 K. However, europium oxide exhibited an abnormal behavior in solubility and redox chemistry. The solubility of europium oxide was measured to be 1-2 order of magnitude higher than those of other lanthanide oxides. This abnormal solubility may be attributable to different electrochemical behavior of europium in the same experimental conditions. Most lanthanides ion exists as trivalent oxidation states. However, we observed divalent europium dissolved in LiCl-KCl molten salt by applying electron paramagnetic resonance(EPR) spectroscopy. (Figure 1) With the ...

British Library Electronic Table of Contents (United Kingdom)

Regular physical activity (PA) decreases the risk of several chronic diseases including some cancers, type II diabetes, obesity, and cardiovascular disease; however, the majority of US adults are not meeting the recommended levels to experience these benefits. To address this public health concern, the underlying mechanisms for behavior change need to be understood, translated and disseminated into appropriately tailored interventions. The Transtheoretical Model (TTM) provides a framework for both the conceptualization and the measurement of behavior change, as well as facilitating promotion strategies that are individualized and easily adapted. The purpose of this manuscript is to present the constructs of the TTM as they relate to PA behavior change. We begin with a brief synopsis of rec...

Energy Technology Data Exchange (ETDEWEB)

Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

Energy Technology Data Exchange (ETDEWEB)

Heat-of-fusion storage materials for low temperature latent heat storage in the temperature range 0-120 C are reviewed. Organic and inorganic heat storage materials classified as paraffins, fatty acids, inorganic salt hydrates and eutectic compounds are considered. The melting and freezing behavior of the various substances is investigated using the techniques of Thermal Analysis and Differential Scanning Calorimetry. The importance of thermal cycling tests for establishing the long-term stability of the storage materials is discussed. Finally, some data pertaining to the corrosion compatibility of heat-of-fusion substances with conventional materials of construction is presented.

Energy Technology Data Exchange (ETDEWEB)

Corrosion behavior of deposition coated specimens prepared by the technique proposed by the authors is investigated in salt immersion tests, and also those of pure magnesium, 3N, 4N and 6N grades, and magnesium alloys, AZ31 and AZ91E, are investigated for comparison. Inhomogeneous corrosion occurs in AZ31 and AZ91E alloys when buffered solutions with pH values of 6.5 and 9.0 including 1% NaCl and a conventional 3% NaCl solution are used for immersion tests, while 6N-Mg shows homogeneous corrosion in such solutions. Corrosion behavior of the deposition coated specimen resembles that of 6N-Mg. Purification process included in the deposition coating technique provides homogeneity in microstructural and electrochemical terms, which results in improving corrosion resistance. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Proteins aggregated into spherulite structures of amyloid fibrils have been observed in patients with certain brain diseases such as Alzheimers and Parkinsons. The conditions under which these protein spherulites form and grow are not currently known. In order to illuminate the role of environmental factors on protein spherulites, this research aims to explore the kinetics and mechanisms of spherulite formation and growth, as monitored by optical microscopy, in a range of salt concentrations, and initial protein concentrations for two model proteins: bovine b-lactoglobulin and insulin. These two proteins are significantly different in their size and fibril growth rate, but both of these proteins have been shown previously to form amyloid fibrils and spherulites under low pH conditions. The...

International Nuclear Information System (INIS)

Polyamide is a modifier which introduces flexibility and toughness to phenolic foam by non reactive approach. Phenol formaldehyde resin was physically modified by the addition of polyamide in different percentages ranging from 0.05% to 0.2% which introduced toughness to modified resole. The resultant polymers were characterized by thermal and mechanical analysis using Thermogravimetric Analyzer (TGA), Instron machine and Dynamic Mechanical Analyzer (DMA). (author)

Energy Technology Data Exchange (ETDEWEB)

Nanocomposites containing polyethylene (PE) and montmorillonite clay organically modified (OMMT) with quaternary ammonium salts were obtained via direct melt intercalation. A montmorillonite sample from the Brazilian state of Paraiba was treated with four different types of quaternary ammonium salts. After the treatment, the powder was characterized by X-ray diffraction and scanning electron microscopy. The dispersion and morphologies of OMMT within PE were investigated by X-ray diffraction and transmission electron microscopy. The results revealed the formation of intercalated montmorillonite layers in the PE matrix. The thermal stability and flammability of the PE/montmorillonite clay nanocomposites were measured by thermogravimetry and horizontal burning tests for HB classification, Underwrites Laboratories (UL 94), respectively. It was shown that the samples do not degrade at the processing temperature. By adding only 3 wt.% ...

Energy Technology Data Exchange (ETDEWEB)

Single-electrode transient behavior was measured mainly during the discharging process for a model cell of electric double layer capacitor with nano-porous carbon electrodes and reference electrode. Apparent conductivity in the cell, which we call `effective conductivity,` is determined with approximation of current in transient behavior to a one-dimensional electrophoretic model. A comparison of effective conductivity with conductivity of bulk solution suggests an interesting mechanism of transfer of electrolyte ions. The difference in transient behavior between various electrolyte ions was not conspicuous in spite of distinctive differences in conductivity of each bulk solution. The large pore diameter of the carbon electrode results in rapid transient behavior and such an electrode should be suitable for rapid charge and discharge. The effect of origin of carbon electrode is ...

UK PubMed Central (United Kingdom)

The hierarchical arrangement of collagen and mineral into bone tissue presumabley maximizes fracture resistance with respect to the predominant strain mode in bone. Thus, the ability of cortical...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The crack growth behavior and fracture toughness of two laminated metal composites (6090/SiC/25p laminated with 5182 and ultrahigh-carbon steel laminated with brass) have been studied in both ``crack arrester`` and ``crack divider`` orientations. The mechanisms of crack growth were analyzed and extrinsic toughening mechanisms were found to contribute significantly to the toughness. The influence of laminate architecture (layer thickness and component volume function), component material properties and residual stress on these mechanisms and the resulting crack growth resistance are discussed.

Energy Technology Data Exchange (ETDEWEB)

This study presents three-dimensional simulation results of multispecies and multi-reaction electrorefining for spent nuclear waste treatment. Fluid-dynamic behavior of electrorefining is analyzed by commercial computational fluid-dynamics code. The results of local fluid dynamics are coupled with one-dimensional electrochemical reaction analysis code in order to predict local current density distribution. The new approach shows current distribution patterns over the cathode surface in LiCl-KCl molten-salt electrolyte. The current density distribution patterns are analyzed for various electrode rotational speeds and diverse applied currents and the results show a good agreement with general principle of mass transfer observations. Spatially periodic and vertically striped pattern of current density is predicted at the cathode side due to mass transfer depression at separation points. These slow mass transfer regions are vulnerable to be ...

British Library Electronic Table of Contents (United Kingdom)

The electroreduction process of Zr(IV) was studied at molybdenum electrode in LiCl-KCl-K2ZrF6 molten salt. The transient electrochemical techniques, such as cyclic voltammetry and chronopotenimetry were used. The experimental results showed that the electrochemical reduction of Zr(II)/Zr and Zr(IV)/Zr(II) were both diffusion-controlled process. In the 773-973K range, the diffusion coefficients of Zr(ii) and Zr(IV) were determined: DZr(II)=0.15567exp{-69.65x10^3RT(K)}cm^2/s, DZr(IV)=1.09x10^-^4exp{-44.39x10^3RT(K)}cm^2/s. The activation energy values for the diffusion process were 69.65kJ/mol and 44.39kJ/mol, respectively.

Energy Technology Data Exchange (ETDEWEB)

The initiation and inhibition of pitting corrosion on zirconium and hafnium in aqueous solutions have been investigated by potentiodynamic, potentiostatic and galvanostatic measurements at 25/sup 0/C. Effects of Cl/sup -/, Br/sup -/and I/sup -/ have been examined over a range of salt concentrations and pH. All three halide ions cause pitting attack on the two metals, but this may be inhibited by other anions. The results show that hafnium is more easily protected against pitting than is zirconium. The data are treated by the Butler-Volmer equation to yield more information about the mechanisms of the pitting corrosion.

International Nuclear Information System (INIS)

This report reviews the published literature on the anaerobic oxidation of iron in aqueous solutions which are of particular relevance to Swedish granitic groundwaters. The thermodynamics of iron corrosion in water are briefly considered. Following this the experimental data found in the literature are presented and discussed. Results were found for corrosion of iron in both pure water and solutions containing mineral salts. The literature work in the nature of the films formed on iron surfaces under anaerobic conditions is reviewed and the possible mechanisms of film formation are discussed. Conclusions are drawn on the factors most likely to influence and control film growth. 32 refs.

Science.gov (United States)

Ni-free shape memory alloys are promising functional materials for medical applications. A newly developed Ti-Mo based shape memory alloy shows superelasticity after thermomechanical treatment. However, the microstructure evolution and precipitation during thermomechanical processes are still not well understood. In the present paper, compressive deformation behavior at a series of temperatures of 298K - 973K and tensile deformation behavior of the alloy after aged at 573K - 973K have been investigated systematically. It is found that the compressive yield stress and ultimate compressive strength change with the deformation temperature. The ultimate tensile strength and yield stress of aged specimens also change with the aging temperature following a non-linear relationship. Microstructures of aged specimens as well as effects of lattice softening and aging-induced precipitates on the deformation behavior have been ...

Energy Technology Data Exchange (ETDEWEB)

The behavior of air flows in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these flow features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.

International Nuclear Information System (INIS)

Ppercase(femaxi-iv) is a computer code for the analysis of thermal and mechanical behavior of light water reactor fuel rods during steady-state and transient conditions. The main purpose of ppercase(femaxi-iv) is to calculate the stress and strain distributions in the fuel and cladding due to the pellet-cladding mechanical interaction, and the fission gas release rate during operations, especially power transients. The capability of ppercase(femaxi-iv) was extensively tested with a number of experimental results obtained in some international fuel irradiation programs. This paper provides a general description of the various models involved in ppercase(femaxi-iv) and some results of applications on the experimental data. ((orig.)).

International Nuclear Information System (INIS)

An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of BEntonite-based and CEment-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field which is one of the important environmental conditions in the safety assessment of the TRU waste disposal. MACBECE is the system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently calculates their hydraulic conductivity taking both their chemical property changes and deformation into consideration. By using MACBECE, the long-term deformation and the transition of hydraulic field for the round-type disposal cavities were evaluated, assuming some sets of chemical evolution data as input. Based on the analysis result, it is considered that the influence of the long-term ...

Energy Technology Data Exchange (ETDEWEB)

When the foundations of the building are designed and worked, the prediction calculation of immediate settlement of the building exercised practically is to calculate assuming the earth is a linear elastic body, but the actual stress-strain relationship of the earth is nonlinear and rigidity of the earth becomes lower as strain (or stress) increases. Hence in order to grasp the actual settling behavior of the earth, it is necessary to elucidate the nonlinear relationship between stress and strain. In this article, a prediction method of building settlement is introduced which uses an analytical technique of the multi-layered earth by the linear elasticity theory and takes into consideration strain dependency of rigidity of the earth. Part of the conclusion is as follows which has been obtained by studying the settling behaviors observed in examples of vertical loading tests of the pile foundations and the elasto-plastic settlement analytical ...

British Library Electronic Table of Contents (United Kingdom)

On the basis of literary sources and experimental data, the advantages of a monogamous reproductive strategy are analyzed. Monogamous species of Lepidoptera have no postcopulative mechanisms of control over the success of reproductive sperm competition, cryptic female choice, and, probably, the male?s nuptial gift. Selection of the sex partner and of the quality of the future generation is determined by the precopulative and copulative mechanisms of the reproductive behavior, which include chemocommunication and a ?lock-and-key? mechanism. In an experiment with one male and one female, the quota of successful mating can depend on the morphological complication of the genital apparatus of males. Cases are considered of repeated mating for some, usually monogamous, species. In comparison wit...

Energy Technology Data Exchange (ETDEWEB)

Studies are made on electrode behaviors of hydride ion in eutectic LiCl-KCl molten salt by various electrochemical methods. As a result, it is confirmed and clarified, by cyclic voltammetry, that anode reaction of hydride ion exists and it is a diffusion-controlled, reversible and one-electron reaction. Also, generation of hydrogen gas is confirmed by a potentiostatic electrolysis, and the electrolysis in the current efficiency of about 95% is possible by controlling electric potential. Moreover, results of chronopotentiometry and chronoamperometry show that hydride ion is anodically oxidized by the diffusion controlling reaction and the reaction itself is reversible. Results of cyclic voltammetry indicate that a diffusion constant D{sub H} {sup {minus}} equals 3.0 {times}10 {sup {minus}5}cm{sup 2}{center dot}S{sup {minus}1} (425 centigrade). This value corresponds well to the values estimated from chronopotentiometry and chronoamperometry. 9 ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is the comparative study of the properties of the natural graphite/liquid organic electrolyte interface by impedance spectroscopy with respect to different lithium salts (LiX with X = ClO{sub 4}{sup -}, BF{sub 4}{sup -}, CF{sub 3}SO{sub 3}{sup -}, N(CF{sub 3}SO{sub 2}){sub 2}{sup -}, PF{sub 6}{sup -}). The evolution of the interface properties during the first electrochemical reduction suggests different mechanisms of formation of passivation films. A more stable, thin and homogenous film seems to develop when the LiN(CF{sub 3}SO{sub 2}){sub 2} or LiPF{sub 6} lithium salts are used. The chemical diffusion coefficient of lithium in graphite has been determined by impedance spectroscopy. (J.S.) 16 refs.

International Nuclear Information System (INIS)

Nanoindentation was performed on a Mo-alloy single crystal to investigate effects of focused ion beam (FIB) milling on mechanical behavior. On a non-FIB-milled surface, pop-ins were observed on all load-displacement curves corresponding to a transition from elastic to plastic deformation. Similar pop-ins were not detected on surfaces subjected to FIB milling. This difference indicates that FIB milling introduces damage that obviates the need for dislocation nucleation during subsequent deformation. A second effect of FIB milling is that it increased the surface hardness. Together, these effects could be the source of the size effects reported in the literature on micropillar tests.

Energy Technology Data Exchange (ETDEWEB)

In the present paper, the chemical composition of passive films formed on both phases of two types of duplex stainless steels (UNS S31803 and UNS S32304) is determined at the micro-scale using Auger electron spectroscopy (AES). Samples were either mechanically polished (down to diamond pastes) or electrochemically etched in acidic solutions. The micro-electrochemical behavior of samples was then determined in sodium chloride media by means of the electrochemical micro-cell technique (capillary diameters of 30 {mu}m). The results obtained were analyzed considering the passive film chemical composition. Quantitative relationships between electrochemical parameters and the distribution of chromium and iron in the oxide layer were found. Due to differences in mechanical properties between ferrite and austenite, a heterogeneous stress distribution is generated in both phases. A method based on ...

Energy Technology Data Exchange (ETDEWEB)

Different experimental measurements (Theology, granulometry, XRD) were carried out in order to study the main properties of bentonite suspensions in presence of anionic additives at different concentrations. These additives are: Sodium Dodecyl Sulfate (SDS) as surfactant, a flexible polymer (Sodium Carboxy Methyl Cellulose, CMC) and a semi-rigid polymer (Xanthan gum). It has been shown that the structural nature of anionic additive influences directly the mixtures viscoelastic and flow behavior. The steric effect of the surfactant modifies the Face-Edge interactions and yields changes of the mixtures rheological behavior at low deformation rates. Polymers act by coating each clay particle and prevent their agglomeration. Therefore, bentonite has no direct effect on the rheological behavior of the mixtures: the additives are responsible for the mechanisms of de-structuration and structure reorganization ...

Science.gov (United States)

In spite of recent education reform and reorganization efforts requiring the use of research-based methods, the fundamental elements of an effective program for children and youth with emotional and behavioral disorders (EBD) have not been succinctly identified. This article presents the essential features of programs for students with EBD. Program elements include (a) qualified and committed professionals, (b) utilitarian environmental supports, (c) effective behavior management plans, (d) valid social skill and social interpretation training and social interaction programs, (e) proven academic support systems, (f) strong parent- and family-involvement programs, (g) coordinated community support mechanisms, and (h) ongoing evaluation of essential program components and student outcomes and progress. A justification for the program and a comparison of the proposed program with existing models is included in the discussion. ...

CERN Document Server

We present a detailed analysis of the self-organization phenomenon in which the stylized facts originate from finite size effects with respect to the number of agents considered and disappear in the limit of an infinite population. By introducing the possibility that agents can enter or leave the market depending on the behavior of the price, it is possible to show that the system self-organizes in a regime with a finite number of agents which corresponds to the stylized facts. The mechanism to enter or leave the market is based on the idea that a too stable market is unappealing for traders while the presence of price movements attracts agents to enter and speculate on the market. We show that this mechanism is also compatible with the idea that agents are scared by a noisy and risky market at shorter time scales. We also show that the mechanism for self-organization is robust with respect to ...

International Nuclear Information System (INIS)

The present work is a research of the effect of helium on the microstructure, mechanical properties and fracture behaviors of a type 316 austenitic steel. Helium implantation was performed by 30-MeV #alpha#-particle injection on very small size specimens, using a cyclotron. Average helium content in a He-deposited region was up to 2000 appm He. In the case of 2000appm He implantation, intergranular fracture was sometimes observed on the helium deposited region after tensile test at room temperature. At elevated temperature test, however, this material showed the transition of fracture mode from transgranular-ductile fracture at 773K to intergranular fracture at 873. In the case of 500 appm He implantation, the transition of fracture mode was recognized at a temperature range of 873K to 973K. (author).

Science.gov (United States)

Understanding the influence of interfacial structures on the nanoarchitecture mechanical properties is of particular importance for its mechanical applications. Due to a small size of constituting nanostructural units and a consequently high volume ratio of such interfacial regions, this question becomes crucial for the overall mechanical performance. Boron nitride bamboo-like nanotubes, called hereafter boron nitride nanobamboos (BNNBs), are composed of short BN nanotubular segments with specific interfaces at the bamboo-shaped joints. In this work, the mechanical properties of such structures are investigated by using direct in situ transmission electron microscopy tensile tests and molecular dynamics simulations. The mechanical properties and deformation behaviors are correlated with the interfacial structure under atomic resolution, and a geometry ...

Energy Technology Data Exchange (ETDEWEB)

Metal nanoparticles have many potential technological applications. Biological routes to the synthesis of these particles have been proposed including production by vascular plants, known as phytoextraction. While many studies have looked at metal uptake by plants, particularly with regard to phytoremediation and hyperaccumulation, few have distinguished between metal deposition and metal salt accumulation. This work describes the uptake of AgNO{sub 3}, Na{sub 3}Ag(S{sub 2}O{sub 3}){sub 2}, and Ag(NH{sub 3}){sub 2}NO{sub 3} solutions by hydroponically grown Brassica juncea and the quantitative measurement of the conversion of these salts to silver metal nanoparticles. Using X-ray absorption near edge spectroscopy (XANES) to determine the metal speciation within the plants, combined with atomic absorption spectroscopy (AAS) for total Ag, the quantity of reduction of Ag{sup I} to Ag{sup 0} is reported. Transmission electron microscopy (TEM) ...

UK PubMed Central (United Kingdom)

BackgroundGlycochenodeoxycholate (GCDA) is one of the major human bile salts. Bile salts stimulate cell survival and proliferation through the mitogen-activated protein kinase, but...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Improved radionuclide generator include a substantially insoluble salt of a radioactive parent which may be directly packed in column for subsequent elution of the daughter radionuclide. An improved 188Re generator was prepared by reacting a radioactive tungsten (188W) as parent radionuclide incorporated with aluminum chloride to obtain an insoluble radioactive aluminum tungstate matrix. The investigated matrix was characterized on the basis of the chemical composition, IR, thermal analysis and mechanical stabilities. The factors affecting the elution performance were studied such as influence of pH, molar ratio and drying temperature. From the obtained data, the molar ratio W:Al was 1.5:1 at pH?=?4, the matrix dried at 105??C for 2 h. Chromatographic and multichannel analysis has been cur...

International Nuclear Information System (INIS)

The structural stability, electronic and elastic properties of ScN under high pressure were investigated by using full-potential linearized augmented plane-wave (FP-LAPW) method. Our calculations indicate that there exists a pressure-induced structural phase transformation from the ambient rock-salt (B1) phase to CsCl-type (B2) phase above 335 GPa. The origin of moderate high bulk modulus, mechanical and high melting point was analyzed by electronic properties. The variations of elastic constants (C_i_j) with volume and pressure have been investigated. Moreover, the volume dependencies of Debye temperature, the longitudinal and transverse elastic wave velocities have been presented.

Energy Technology Data Exchange (ETDEWEB)

Using the [sup 57]Fe Moessbauer spectroscopy, the microscopic behavior of Fe powders has been investigated during and after the mechanical alloying (MA) process for Al-Fe and Ag-Fe systems. A repeated rolling method as well as a conventional ball-milling method are employed in order to understand the microscopic process of the kneading of Al and Fe powders during their MA and the resultant powders show quite similar Moessbauer spectra suggesting that the kneading by an impact between colliding balls is the same process as that of the thickness reduction by cold rolling. Moessbauer spectra show clearly the occurrence of the mutual atomic dispersion for the thermodynamically immiscible Ag-Fe system. (orig.).

Science.gov (United States)

The goal of this research program has been to add to our understanding of the breakup of molten fuel jets penetrating reactor coolant. Easily handled working fluids are used to simulate fuel jet breakup, so that detailed observations may be obtained from a relatively large number of experiments. The tools used for observing this behavior are high speed notion picture photography, Flash X-radiography, and X-ray cine. Jet breakup lengths are determined from motion pictures; the mechanisms by which the jets are fragmented may be inferred from radiographs.

UK PubMed Central (United Kingdom)

Numerous bacteria from a salt-marsh environment are capable of degrading malathion, an organophosphate insecticide, when supplied with additional nutrients as energy and carbon sources. Seven isolates...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This article describes acoustic methods used in the in-service inspection of the dams and peripheral concrete structures of the Toktogul, Kurpsai, and Bratsk hydroelectric and pumped storage plants. The tests were conducted to assess the compression strength, elasticity, and tensile strength of the concretes. Comparative evaluations against drill core studies proved the acoustic methods to be sufficiently accurate in predicting aging behavior and loss of mechanical and physical integrity in the concretes.

Energy Technology Data Exchange (ETDEWEB)

Over the last year-and-a-half, several 4-cm-aperture, 17-m-long dipole magnet prototypes were built by Brookhaven National Laboratory (BNL) under contract with the Superconducting Super Collider (SSC) Laboratory. These prototypes are the last phase of a half-decade-long R D program, carried out in collaboration with Fermi National Accelerator Laboratory and Lawrence Berkeley Laboratory, and aimed at demonstrating the feasibility of the SSC main ring dipole magnets. They also prepare the way of the 5-cm-aperture dipole magnet program to be started soon. In this paper, we analyze the mechanical behavior of the BNL prototypes during cool-down and excitation, and we attempt to relate this behavior to the magnet features. The data reveal that the mechanical behavior is sensitive to the vertical collar-yoke interference, and that the magnets exhibited somewhat erratic changes in coil ...

International Nuclear Information System (INIS)

Minor addition of B to the Ti-6Al-4V alloy reduces the prior #beta# grain size by more than an order of magnitude. TiB formed in-situ in the process has been noted to decorate the grain boundaries. This microstructural modification influences the mechanical behavior of the Ti-6Al-4V alloy significantly. In this paper, an overview of our current research on tensile properties, fracture toughness as well as notched and un-notched fatigue properties of Ti-6Al-4V-xB with x varying between 0.0 to 0.55 wt.% is presented. A quantitative relationship between the microstructural length scales and the various mechanical properties have been developed. Moreover, the effect of the presence of hard and brittle TiB has also been studied.

British Library Electronic Table of Contents (United Kingdom)

Abstract The effects of the type of coupling agent and virgin polypropylene (PP) content on the mechanical properties and water absorption behavior of recycled low-density polyethylene/wood flour (WF) composites were investigated. The fractured surfaces of these recycled wood/plastic composites (rWPCs) were examined to gain insight into the distribution and dispersion of WF within the polymer matrix. The results indicate that the use of 100% recycled polymer led to inferior mechanical properties and to a greater degree of moisture absorption and swelling when compared to recycled polymer-virgin PP wood/plastic composites. This could have been related to the poor melt strength and inferior processability of the recycled polymer. The extent of improvement of the mechanical properties depende...

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The conversion of highly radioactive waste liquor into glass by the pot vitrification process has been studied at Harwell using a full-scale inactive pilot plant. A summary of the off-gas behavior and its interpretation is presented. Experimental runs were carried out on 3 representative wastes (MAGNOX - thermal reactor, metal fuel, THORP - thermal oxide fuel and PFR - fast reactor oxide fuel) using 2 methods of feeding the glass-formers (slurry and crizzle). Materials were carried over from the vitrification vessel into the off-gas system by entrainment supplemented by volatilization. The overall behavior of the off-gas was consistent with the presence in it of 5 separate aerosols of particulate matter. Sources of entrainment gave rise to 3 aerosols, and a further 2 aerosols were formed as a result of chemical reaction (Ru) and condensation (Cs) processes involving the volatile species. Entrainment was enhanced when the feed contained free ...

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Under the auspices of the Mine Environment Neutral Drainage (MEND) Program, several waste rock piles were monitored and characterized. Acid rock drainage (ARD) became a mechanism better understood based on the data acquired during these projects. Numerical simulation was used to better comprehend the quantitative issues associated with the characterization of three specific sites for the purpose of this study. The sites selected were the south waste rock pile of the Doyon Mine in Quebec, the Northdale of the mining district of Ronnenberg in Germany, and the waste rock pile of the Sugar Shack South of the Questa mine in New Mexico. The observed and simulated conditions were very distinct from one mine to another, even if the same mechanisms were involved. The dominant oxygen and heat transfer mechanisms displayed the most varied behavior between the sites. ARD control or site rehabilitation decisions ...

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Polysaccharides like cellulose and chitosan are known for their filmic properties. This paper concerns the synthesis and the study of chitosan-based polymer electrolytes. A preliminary work concerns the study of glucosamine reactivity. The poly-condensation of chitosan ethers (obtained by reaction with ethylene oxide or propylene oxide) with bifunctional and monofunctional oligo-ethers leads to the formation of thin lattices (10 {mu}m) having excellent mechanical properties. The presence of grafted polyether chains along the polysaccharide skeleton allows to modify the vitreous transition temperature and the molecular disorder of the system. Two type of polymer electrolytes have been synthesized: electrolytes carrying a dissolved alkaline metal salt and ionomers. The analysis of their thermal, dynamical mechanical, nuclear magnetic relaxation, electrical, and electrochemical properties shows that this new class of polymer ...

Energy Technology Data Exchange (ETDEWEB)

The deformation characteristics of pellets of electrolyte-binder (EB) mixes based on MgO were measured under simulated, thermal-battery conditions. Measurements (using a statistically designed experimental strategy) were made as a function of applied pressure, temperature, and percentage of theoretical density for four molten-salt electrolytes at two levels of MgO. The EB mixes are used as separators in Li-alloy thermal batteries. The electrolytes included LiCl-KCI eutectic, LiCl-LiBr-KBr eutectic, LiBr-KBr-LiF eutectic, and a LiCl-LiBr-LiF electrolyte with a minimum-melting composition. The melting points ranged from 313 C to 436 C. The experimental data were used to develop statistical models that approximate the deformation behavior of pellets of the various EB mixes over the range of experimental conditions we examined. This report, discusses the importance of the deformation response surfaces to thermal-battery design.

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

The widespread use of tobacco and alcohol among adolescents might be related to the ability of nicotine and ethanol to facilitate social interactions. To investigate the neurobehavioral mechanisms underlying the prosocial effects of nicotine and ethanol, we focused on social play behavior, the most characteristic social activity in adolescent rats. Social play behavior is rewarding, and it is modulated through opioid, cannabinoid and dopaminergic neurotransmission, which are also involved in the reinforcing properties of nicotine and ethanol. We found that nicotine and ethanol increased social play, without affecting locomotion or social exploration. Their effects depended on the level of social activity of the partner, and were comparable in familiar and unfamiliar environments. At doses that increased social play, nicotine and ethanol had no anxiolytic effects in the elevated plus-maze. By contrast, the prototypical ...

British Library Electronic Table of Contents (United Kingdom)

In this study polycrystalline specimens of as-cast DyCu with B2 crystal structure were compressed to different strains at room temperature to test if stress-induced phase transformation and twinning occur during deformation. In these tests DyCu exhibited high ductility with plastic strain as high as 35% and ultimate compressive strength of ~790MPa. X-ray diffraction and transmission electron microscopy (TEM) showed no indications that DyCu had undergone stress-induced phase transformation or twinning. -type dislocations have been observed to play an important role for imparting the ductile behavior. TEM analyses showed the presence of second phases, Dy2O3 and DyCu2 within the DyCu. The mechanisms of ductility and impurity phase formation are discussed.

British Library Electronic Table of Contents (United Kingdom)

Action potentials from the brain control the activity of spinal neural networks to produce, by as yet unknown mechanisms, a variety of motor behaviors. Particularly lacking are details on how identified descending neurons integrate diverse sensory inputs to generate specific locomotor patterns. We have examined the operations of the principal neurons in an intriguing midbrain nucleus, the nucleus of the medial longitudinal fasciculus (nMLF), in the larval zebrafish. The nMLF is the most rostral grouping of neurons that projects from the brain well into the spinal cord of teleost fishes, yet there is little direct physiological data available regarding its function. We report here that a distinct set of large, individually-identifiable neurons in nMLF (the MeL and MeM neurons) are activated...

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This report describes experimental results for the selective removal of strontium and cesium from simulated waste solutions using monosodium titanate (MST) and crystalline silicotitanate (CST)-laden filter cartridges. Four types of ion exchange cartridge media (CST and MST designed by both 3M and POROX{reg_sign}) were evaluated. In these proof-of-principle tests effective uptake of both Sr-85 and Cs-137 was observed. However, the experiments were not performed long enough to determine the saturation levels or breakthrough curve for each filter cartridge. POREX{reg_sign} MST cartridges, which by design were based on co-sintering of the active titanates with polyethylene particles, seem to perform as well as the 3M-designed MST cartridges (impregnated filter membrane design) in the uptake of strontium. At low salt simulant conditions (0.29 M Na{sup +}), the instantaneous decontamination factor (D{sub F}) for Sr-85 with the 3M-design MST cartridge measured 26, ...

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In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using two different thermal-hydraulic loops. The main focus of the experiment was the two-phase flow behavior in the hot-leg U-bend typical of BandW LWR systems. The first group of experiments was carried out in the nitrogen gas-water adiabatic simulation loop and the second in the Freon 113 boiling and condensation loop. Both of the loops have been designed as a flow visualization facility and built according to the two-phase flow scaling criteria developed under this program. The nitrogen gas-water system has been used to isolate key hydrodynamic phenomena such as the phase distribution, relative velocity between phases, two-phase flow regimes and flow termination mechanisms, whereas the Freon loop has been used to study the effect of fluid properties, phase changes and ...

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The corrosion behavior of Alloy 800 and Type 316 stainless steel in molten NaNO/sub 3/-KNO/sub 3/ was studied at temperatures from 605/degree/C to 630/degree/C. Corrosion behavior was significantly different from that previously reported in nitrate melts at temperatures up to 600/degree/C and involved a combination of oxidation, internal nitridation and sodium metallate formation. Corrosion kinetics, determined metallographically, switched from a parabolic to a linear rate equation as temperature increased. Corrosion was uniform and resulted in metal losses on the order of 100 micronsyear at 630/degree/C. Among the alloying elements, chromium was depleted from the alloy as the result of a basic fluxing process. The kinetic equations describing chromium depletion also changed from parabolic to linear with increasing temperature. The effect of the equilibrium chemistry of the melt on the corrosion behavior of the alloys is ...

Energy Technology Data Exchange (ETDEWEB)

An axisymmetric unit cell model based on a regular array of second-phase particles arranged on a BCC lattice is used to study deformation mechanisms of ferrite-pearlite structural steels. Microstructural characteristics of the steels were parameterized by the pearlite volume fraction, the aspect ratio of the pearlite particles, and the neighboring factor, which represents the ratio of interparticle spacing in the longitudinal direction to that in the transverse direction. FE analyses were carried out to investigate the macroscopic and microscopic response of unit cells with morphological features based on idealizations of the microstructures of the actual steels. Tensile properties of each constituent phase were obtained experimentally and used in the analyses. As compared to traditional axisymmetric models, the BCC tell model appears to be able to capture more realistically the behavior of the materials, and it accurately estimates the tensile ...

International Nuclear Information System (INIS)

The effect of mean stress, or the stress ratio (R), on the fatigue-crack growth (FCG) behavior of #alpha#-aged and #omega#-aged microstructures of the beta titanium alloy Ti-10V-2Fe-3Al was investigated. While the mean stress had a negligible effect on the FCG behavior of the #alpha#-aged microstructure, a strong effect was observed in the #omega#-aged microstructure. In particular, the values of the threshold stress-intensity range (#DELTA#K_t_h) exhibited a strong dependence on R in the #omega#-aged microstructure, while this dependence was weak in the #alpha#-aged microstructure. These effects seem to arise primarily from fracture-surface roughness-induced crack closure. The crack closure levels for the #alpha#-aged microstructure were found to be very low compared to those for the #omega#-aged microstructure. Transmission electron microscopy and scanning electron microscopy studies of microstructures and fracture surfaces were performed to ...

CERN Document Server

Nonequilibrium statistical mechanics

International Nuclear Information System (INIS)

After being pre-plated a zinc layer, an amorphous Al-Mn alloy coating was applied onto the surface of AZ31B magnesium alloy with a bath of molten salts. Then the corrosion performance of the coated magnesium alloy was examined in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the single Zn layer was active in the test solution with a high corrosion rate while the Al-Mn alloy coating could effectively protect AZ31B magnesium alloy from corrosion in the solution. The high corrosion resistance of Al-Mn alloy coating was ascribed to an intact and stable passive film formed on the coating. The performances of the passive film on Al-Mn alloy were further investigated by Mott-Schottky curve and X-ray photoelectron spectroscopy (XPS) analysis. It was confirmed that the passive film exhibited n-type semiconducting behavior in 3.5% NaCl solution with a carrier density two ...

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Modelization of crack propagation and theoretical prediction of rupture are the two main objectives of researchers in stress corrosion cracking. Nevertheless, to reach this aim, the behavior of the passive film which appears spontaneously on the substrate in contact with an environment has to be known. This structural and mechanical characterization is all the more difficult because the number of parameters is important: crystallinity rate, defects concentration, thickness (about a few nanometers), electric field, chemical composition (a lot of oxides are present), peeling layers (atomic structure for example) and some hypothesis can be made about their multi-layer structure, their chemical composition or their epitaxial character... Passive films formed on 316L or 304L stainless steels in different aqueous solutions (in ambient air, in MgCl{sub 2} at 117 deg. C...) have been studied and some important remarks about their ...

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The current specifications of the LLNL fusion-fission hybrid proposal, namely LIFE, impose severe constraints on materials, and in particular on the nuclear fissile or fertile nuclear fuel and its immediate environment. This constitutes the focus of the present report with special emphasis on phase formation and phase transformations of the transmutation fuel and their consequences on particle and pebble thermal, chemical, and mechanical integrities. We first review the work that has been done in recent years to improve materials properties under the Gen-IV project, and with in particular applications to HTGR and MSR, and also under GNEP and AFCI in the USA. Our goal is to assess the nuclear fuel options that currently exist together with their issues. Among the options, it is worth mentioning TRISO, IMF, and molten salts. The later option will not be discussed in details since an entire report (Volume 8 - Molten-salt ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Thermomechanical behavior of membranes based on blends of poly(vinyl alcohol) (PVA) with different weight percentage (wt %) of glycerol has been studied. Solid-state PVA/Glycerol polymer membranes were prepared by a solution casting method. The films were studied for thermal characteristics by differential scanning calorimetry (DSC) and thermogravimetric analysis and for the mechanical properties including hardness and modulus by nanoindentation method. The dispersion of glycerol within the polymer matrix was examined using scanning electron microscopy. Fourier transform infrared spectroscopy was used to confirm the formation of hydrogen bonding between the plasticizer and PVA in their blends and also to provide information on compatibility and physical interactions between the gl...

CERN Document Server

A major goal in optomechanics is to observe and control quantum behavior in a system consisting of a mechanical resonator coupled to an optical cavity. Work towards this goal has focused on increasing the strength of the coupling between the mechanical and optical degrees of freedom; however, the form of this coupling is crucial in determining which phenomena can be observed in such a system. Here we demonstrate that avoided crossings in the spectrum of an optical cavity containing a flexible dielectric membrane allow us to realize several different forms of the optomechanical coupling. These include cavity detunings that are (to lowest order) linear, quadratic, or quartic in the membrane's displacement, and a cavity finesse that is linear in (or independent of) the membrane's displacement. All these couplings are realized in a single device with extremely low optical loss and can be tuned over a wide range in situ; in ...

Energy Technology Data Exchange (ETDEWEB)

Equilibrium and energy equations have been developed in describing the solid-fluid transition zone during the melting and solidification of the binary alloys. Due to the existence of the transition region exhibited both solid and fluid phases at the same material point from continuum point of view, mixture theory was utilized to analyze the region. Unlike the Stefan problem, the latent heat due to the phase change appears as a source term in the heat equation. The molten fluid is treated as a thermoviscous and incompressible fluid, whereas the solid is thermoviscoplastic described by the Bodner-Partom/Walker type of constitutive equations. Thermal mechanical behaviors of the solid and the fluid phases are determined separately because of insignificant mechanical interactions between them. Volume fractions of the phases are obtained according to the equilibrium phase diagram. The simulation process of the transition zone and ...

International Nuclear Information System (INIS)

The grain size dependence of the tensile properties and the deformation mechanisms responsible for those properties are examined for Mg alloy, AZ31B, sheet. Specifically, the Hall-Petch effect and strain anisotropy (r-value) are characterized experimentally, and interpreted using polycrystal plasticity modeling. {1 0 . 2} extension twins, {1 0 . 1} contraction twins, and so-called 'double-twins' are observed via microscopy and diffraction-based techniques, and the amount of twinning is found to increase with increasing grain size. For the sheet texture and tensile loading condition examined, {1 0 . 2} extension twinning is not expected, yet the polycrystal plasticity model predicts the observed behavior, including this 'anomalous' tensile twinning. The analysis shows that the Hall-Petch strength dependence, of the polycrystal as a whole, is primarily determined by the grain size dependence of the strength of the prismatic slip systems.

Energy Technology Data Exchange (ETDEWEB)

Effect of alcohol solvent in mixing process on process on the microstructure and sintering behavior of ceramic-based composites was inestigated in detail. The mixture of fine ceramic powders was prepared through the conventional ball-milling method with various alcohol media. The particle distributions of fine ceramic powders were strongly dependent on the kind of alcohol employed during ball-milling. Ceramic-based composites were fabricated by hot-pressing the mixture of fine ceramic powders. Their microstructures and some mechanical properties of the ceramic-based composites were evaluated. It was found that the viscosity of alcohol, surface tension and contat angle greatly affect the sinterbility and some of the mechanical properties of ceramic-based somposites. (author)

Energy Technology Data Exchange (ETDEWEB)

A joint materials test program developed by the Institute for Mining and Minerals Research (IMMR) and the Tennessee Valley Authority (TVA) involved the postexposure mechanical properties and corrosion behavior of candidate structural materials in an experimental, atmospheric fluidized-bed combustor (AFBC). This combustor was operated by Accurex Corporation at Research Triangle Park, North Carolina, under the direction of TVA. The materials studied were Type 304, Type 310, and INCOLOY alloy 800 in the form of disc coupons with and without crevice configurations. Type 304 was also used for mechanical property measurements. The alloys were exposed to the combustor environment at about840/sup 0/C for approximately 330 hours. The ranking in terms of decreasing weight loss was: (1) Type 304, (2) Type 310, and (3) INCOLOY alloy 800. The presence of tight crevices did not enhance the corrosion rate. In addition, the corrosion ...

International Nuclear Information System (INIS)

The phase separation of (water + salt + polyethylene glycol 15000) systems was studied by cloud-point measurements using the particle counting method. The effect of three kinds of sulphate salt (Na2SO4, K2SO4, (NH4)2SO4) concentration, polyethylene glycol 15000 concentration, mass ratio of polymer to salt on the cloud-point temperature of these systems have been investigated. The results obtained indicate that the cloud-point temperatures decrease linearly with increase in polyethylene glycol concentrations for different salts. Also, the cloud points decrease with an increase in mass ratio of salt to polymer.

Energy Technology Data Exchange (ETDEWEB)

The exposure of heat-resistant alloys to high temperature can significantly change their mechanical properties. This paper presents and analyzes data on the effect of thermal exposure on the tensile and impact behavior of three cast materials -- the HK-40, HP-50, and 21Cr-32Ni-Fe alloys -- and of wrought material -- Alloy 800. The changes in tensile and impact properties caused by high-temperature exposure are reviewed. Reasons for these property changes and needs for considering them in the design, operation, and life assessment of high-temperature equipment are discussed.

British Library Electronic Table of Contents (United Kingdom)

In the last 40 years, significant advances have been made in the understanding of the neurophysiologic processes involved in the experience of trauma and pain. This knowledge, together with the rapid growth and understanding in the behavioral health sciences, has expanded to include a much better appreciation of how these fields are converging and contribute to a process called neuroplasticity. These basic mechanisms common to all patients have important implications for clinical outcome and for improving clinical practice. This article is written for clinicians who manage patients with sacroiliac joint dysfunction, a specific type of nonspecific low back pain.

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional magnetohydrodynamic simulations are executed in a full toroidal geometry to clarify the physical mechanisms of the Internal Reconnection Event (IRE), which is observed in the spherical tokamak experiments. The simulation results reproduce several main properties of IRE. Comparison between the numerical results and experimental observation indicates fairly good agreements regarding nonlinear behavior, such as appearance of localized helical distortion, appearance of characteristic conical shape in the pressure profile during thermal quench, and subsequent appearance of the m=2/n=1 type helical distortion of the torus. (author)

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'Objective of this project is to develop and use Electrochemical Emission Spectroscopy (EES) and other electrochemical techniques as in situ tools for exploring corrosion mechanisms of iron and carbon steel in highly alkaline solutions and for continuously monitoring corrosion on structural materials in DOE liquid waste storage system. In particular, the author will explore the fundamental aspects of the passive behavior of pure iron since breakdown of passivity leads to localized corrosion. This report summarizes work after 1 year of a 3 year project.'

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The US Department of Energy is currently constructing the Waste Isolation Pilot near Carlsbad, New Mexico. The full-scale pilot plant will demonstrate the feasibility of the safe disposal of defense-related nuclear waste in a bedded salt formation at a depth of 2160 feet below the surface. WIPP will provide for the permanent storage of 25,000 cu ft of remote-handled (RH) transuranic waste and 6,000,000 cu ft of contact-handled (CH) transuranic waste. This paper covers the major mechanical/structural design considerations for the waste hoist and its hoist tower structure. The design of the hoist system and safety features incorporates state-of-the-art technology developed in the hoist and mining industry to ensure safe operation for transporting nuclear waste underground. Also included are design specifications for VOC-10 monitoring system.

Science.gov (United States)

Certain materials, especially Sn, passivate the rare earth-exchanged Y zeolite (REY) used in petrochemical fluid-cracking catalysts against vanadium degradation caused by V impurities in the feed oil. The mechanism of passivation was investigated here from the standpoint of high-temperature oxide acid-base reaction; i.e., where the controlling factors were considered to be Lewis acid-base reactions between V{sub 2}O{sub 5}, the RE oxides, SnO{sub 2}, etc. Molten salt tests at 680{degree}C showed SnO{sub 2}, presumably because of its acidic nature, to be essentially nonreactive with V{sub 2}O{sub 5} or Na{sub 2}O-V{sub 2}O{sub 5} compounds. A hypothesis was developed to explain how the passivation effect by Sn might result from the unique resistivity of SnO{sub 2} to reaction with V{sub 2}O{sub 5}.

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This paper indicates first that the base content in desert soil is by far much higher than that in soils in moist areas, that salts with the higher solubility to water have their deposition depth greater, and that the organic content is extremely low. The paper also describes the experiments to verify that the desert soil contains soil lumps with a diameter of about several millimeters, which function effectively to form the long term survival locations for microorganisms. Desert soil containing soil lumps and the one removed of lumps by pulverizing them into powder were prepared as test specimens, which were left submerged. It was confirmed that the velocity of decomposing the organics and the mechanical strength in the latter soil are obviously inferior to those in the former soil. Additional remarks are given that when the desert soil environment is changed the microorganisms get more active appreciably and that certain kinds of mold fungi ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of the conversion process is to convert the {sup 233}U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019.

UK PubMed Central (United Kingdom)

The conformation of the self-complimentary DNA dodecamer d(br5CGbr5CGAATTbr5CGbr5CG) has been investigated in a variety of salt and solvent conditions by one and two-dimensional 1H NMR. In low salt...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

The effect of associative interactions of monomers and propagating macroradicals in homopolymerization of N-[3-(dimethylamino)propyl]methacrylamide salts and their copolymerization with acrylonitrile and acrylamide in aqueous solution was studied.

UK PubMed Central (United Kingdom)

The conformation of d (CG)n oligomers with n = 2,3 has been studied in aqueous solution in the presence of high salt concentration. A minimum n value of three is necessary to obtain a left-handed Z-helix....Full Text Available

International Nuclear Information System (INIS)

Interfacial tension at the aqueous solution of di-2-ethylhexylphosphoric acid or its copper salts/water solutions has been measured by the drop volume method.

International Nuclear Information System (INIS)

Russian (Jul 1974). USSR Buslaev, Yu.A. Petrosyants, SP Tarasov,

KoreaScience (Korea)

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This project has been concerned with the understanding of certain key physical and physical chemical properties of polymeric systems which are related to their use as working substances in mechanochemical systems. Since the crystal-liquid phase transition is involved in the process of interest, attention has been focused on this transition and on the properties of semi-crystalline polymers. Two kinds of behavior and properties have been studied in this program. One of these is concerned with melting-crystallization under an applied external force. Here the primary matters of concern are the equilibrium melting temperature-stress relations and the associated problem of crystallization kinetics under an applied external stress. The other area of study involves mechanical properties, with particular emphasis on the influence of the morphological and structural variables which describe the semi-crystalline state. We have taken advantage in this ...

International Nuclear Information System (INIS)

In 1998, in the frame of the ITER EDA phase, an European R and D Programme for the Blanket Design was implemented for developing and selecting the materials and the relevant fabrication procedures for manufacturing the shielding modules of the ITER Primary Wall. The fabrication of several Beryllium armored small scale mock-ups, reproducing representative portions of a Primary Wall panels, was also launched (Fusion Technol. (1998) 195). Further experimental activities were also programmed for investigating the thermal-mechanical behavior of these mock-ups at high heat flux and under thermal fatigue tests. In 2001, the ITER European Home Team decided to assign to ENEA a contract for the thermal fatigue testing of six mock-ups aiming at verifying the reliability of the Beryllium/Dispersion Strengthened Copper alloy/Stainless Steel and Beryllium/Precipitation hardened Copper alloy/Stainless Steel joints manufactured by solid Hot Isostatic Pressing ...

Energy Technology Data Exchange (ETDEWEB)

Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was {epsilon} {approx}7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

International Nuclear Information System (INIS)

Because of their austenitic-ferritic microstructures, duplex stainless steels offer a good combination of mechanical and corrosion resistance properties. However, heat treatments can lower the mechanical strength of these stainless steels as well as render them susceptible to intergranular corrosion (IGC) and pitting corrosion. In this study, a low-carbon (0.02%) duplex stainless steel is subjected to various heat treatments at 450 to 950 C for 30 min to 10 h. The heat-treated samples than undergo ASTM IGC and pitting corrosion tests, and the results are correlated with the microstructures obtained after each heat treatment. In the absence of Cr_2_3C_6 precipitation, #sigma#-phase precipitates render this duplex stainless steel susceptible to IGC and pitting corrosion. Even submicroscopic #sigma#-phase precipitates are deleterious for IGC resistance. Longer-duration heat treatments (at 750 to 850 C) induce chromium diffusion to replenish the ...

International Nuclear Information System (INIS)

The effects of Fe and B_4C on the sintering behavior and mechanical properties of TiB_2 ceramics have been studied. Sintering was performed in an Ar atmosphere at 2000 degrees C using attrition-milled TiB_2 powder. When a small amount of Fe (0.5 wt%) was added, abnormal grain growth occurred and the sintered density was low. In the case of B_4C added along with 0.5 wt% Fe, however, abnormal grain growth was remarkably suppressed, and the sintered density was increased up to 95% of theoretical. But with excess Fe addition (5 wt%), B_4C grains did not act as a grain growth inhibitor, and B_4C grains were frequently trapped in large TiB_2 grains. The best mechanical properties were obtained for the TiB_2-10 wt% B_4C-0.5 wt% Fe ceramics, which exhibited a three-point bending strength of 400 MPa and a fracture toughness of 5.5 MPa #centre dot# m"1"/"2.

Science.gov (United States)

The mechanical properties of metal stents are important parameters in the consideration of stent design, matched to resist arterial recoil and vascular spasm. The purpose of this study was to develop a system for a standardized quantitative evaluation of the mechanical characteristics of various coronary stents. Several types of stents were compressed by external hydrostatic pressure. The stent diameter was assessed by placing a pair of small ultrasonic sono-crystals on the stent. From pressure-strain diagrams the ultimate strength and radial stiffness for each stent were determined. For all stents, except the MICRO-II and the Wiktor stent, the diameter decreased homogeneously until an ultimate compressive strength was exceeded, causing an abrupt collapse. Expanded to 3 mm, the mechanical behavior of the beStent, the Crown and the Palmaz-Schatz stent (PS153-series) were comparable. The spiral ...

British Library Electronic Table of Contents (United Kingdom)

Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2?weeks of salt treatment with 25, 50, 75 and 100?mM NaCl. Results showed that, growth was reduced even by 25?mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions...

Energy Technology Data Exchange (ETDEWEB)

Strain-induced crystallization of crosslinked natural rubber (NR) and its synthetic analogue, cis-1,4-polyisoprene (IR), both mixed with various amounts of stearic acid (SA), were investigated by time-resolved X-ray diffraction using a powerful synchrotron radiation source and simultaneous mechanical (tensile) measurement. No acceleration or retardation was observed on NR in spite of the increase of SA amount. Even the SA-free IR crystallized upon stretching, and the overall crystallization behavior of IR shifted to the larger strain ratio with increasing SA content. No difference due to the SA was detected in the deformation of crystal lattice by stress for both NR and IR. These results suggested that the extended network chains are effective for the initiation of crystallization upon stretching, while the role of SA is trivial. These behaviors are much different from their crystallization at low temperature by standing, ...

Energy Technology Data Exchange (ETDEWEB)

In order to predict the effect of a fuel-coolant interaction after a hypothetical core-melt-down accident, a phenomenological model has been developed to describe the thermal and hydrodynamic behavior of a high-temperature molten jet when it interacts with saturated or subcooled water in a film boiling regime. The mechanisms of jet-material erosion were analyzed by Kelvin-Helmholtz instabilities on the coherent column and by boundary layer stripping on the leading edge. The heat transfer coefficient, vapor-film thickness, and net steam generation, all of which strongly affect the jet-breakup behavior, were solved analytically. It was found that the jet breakup (or erosion) depends strongly on the steam generation from the jet/water interaction. The jet-breakup length (i.e., penetration distance) was found to be sensitive to the initial jet temperature, water subcooling, and the physical state of the ambient water. The ...

Science.gov (United States)

Ballistics involves the study of the scientific properties of projectiles, their behavior and their terminal effects on biological tissues and other materials. Wound ballistics deals with the analysis of injuries caused by projectiles and the behavior of projectiles within human or other biological tissues. The nineteenth century witnessed the development of both of these areas with Kocher's hydrodynamic theory and the understanding of the significance of bullet deformation in causing tissue injury. The degree of traumatic disruption of tissues and organs was also related to direct energy transfer from projectiles. While subsequent research has concentrated on elucidating further mechanisms of injury, the exact cause of remote tissue damage from high energy projectiles is still the subject of ongoing research. Much of the contemporary literature regarding wound ballistics concentrates on the forensic aspects and their ...

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Graphite fluoride (CF{sub x}) is investigated as an additive for WS{sub 2} thin films to reduce its sensitivity to moisture. The films are grown onto hardened 440C stainless steel disks by pulsed laser deposition using the 248 nm line from an excimer laser. Substrate temperature and additive concentration are varied to control film chemistry and crystal structure. The effect of relative humidity (i.e., < 1 to 85% RH) on friction is evaluated. Coatings grown at RT from targets with a low concentration of CF{sub x} exhibit ultra-low friction (ULF) behavior in dry air (i.e., {mu} {<=} 0.01), but friction increases with RH. Mechanisms for the ULF behavior are proposed which suggest that further reductions in friction are possible. Films grown at 300 C or with higher concentrations of CF{sub x} are relatively insensitive to humidity, but have more typical friction coefficients ({mu} {<=} 0.04) in dry air. (orig.)

Science.gov (United States)

Ionizing radiation is a standard treatment for various human solid tumors. However, several clinical studies showed that a significant proportion of patients undergoing radiotherapy for hepatocellular carcinoma (HCC) develop intrahepatic and extrahepatic metastasis. Understanding of radiation-induced cancer cell invasiveness and behavior is essential and of great important for developing suitable treatment strategies to contain cancer spread. Therefore, in this study we evaluated the effectiveness of using swept source optical coherence tomography (SS-OCT) to monitor the enhancement of HCC cell invasiveness by radiation. SS-OCT images were acquired and recorded to obtain three-dimensional data sets per four hours in 48 hours after irradiating HepG2 cells with 7.5 Gy. The cell migration behavior in three-dimensional tissue models was quantified from images of radiation-induced and sham-irradiated cells.

Energy Technology Data Exchange (ETDEWEB)

The present paper deals with the conversion of solar energy in a gas turbine plant with a parabolic dish collector. Particular consideration is devoted to the thermodynamic and mechanical design and partload behavior of the receiver. The incident sunlight is focussed by the parabolic dish and then beamed into the cavity receiver. Here the working medium of the gas turbine flows through tubes and is heated up to the receiver outlet temperature. The task of the receiver is to transfer the radiated energy as efficiently as possible to the working medium. Furthermore the required heating surface should be small as possible i.e. optimum use must be made of the tube material with respect to its state of stress. It is shown which geometric and thermodynamic plant parameters influence these two design criteria. An optimum receiver design is presented on the basis of the results thus obtained. Finally, the variations in receiver efficiency and tube ...

International Nuclear Information System (INIS)

The results of the thermo-hydro-mechanical (THM) study of the FEBEX bentonite performed during FEBEX II are presented. The laboratory test program continued in part with the works carried out during FEBEX I, particularly in activities related to tests aimed to the calibration of the models, the acquisition of parameters by back-analysis and the improvement of the knowledge on the behaviour of expansive clays. But the program has also included tests on new areas: investigations about the influence of the microstructure changes in bentonite, of temperature and of the solute concentration on the behaviour of clay. Besides, several tests were proposed in order to understand the unexpected behaviour observed in the mock-up test, towards the end of year 2. Temperature effects on water retention curves in confined and unconfined conditions were determined, and swelling pressure, hydraulic conductivity and swelling and consolidation strains as a function of temperature ...

International Nuclear Information System (INIS)

Mn-modified Pb0.92La0.08(Zr0.65Ti0.35)O3 (PLZT) was prepared chemically by a coprecipitate method using their respective nitrate salts and isopropoxides. Differential thermal analysis (DTA) and X-ray analysis clearly show the formation of PLZT single rhombohedral phase for samples calcined beyond 750 C. Uniform grain distribution was observed from scanning electron microscopic (SEM) studies and grain size was found to increase with Mn doping up to x=0.08 and then decreased. Dielectric measurement shows the decrease in peak transition temperature (TC) with Mn doping up to x=0.12 and then increase along with a sharp rise in dielectric maxima. A diffuse dielectric dispersion is observed in all the compositions. A detailed dispersion study was carried out using the Vogel-Fulcher empirical relation, a universal relaxation law and the Havriliak-Negami function. The Vogel-Fulcher relation fitting parameters of activation energy and freezing temperature were found to ...

Energy Technology Data Exchange (ETDEWEB)

Anomalous features in Gulf Coast Salt domes exhibit deviations from normally pure salt and vary widely in form from one dome to the next, ranging considerably in length and width. They have affected both conventional and solution mining in several ways. Gas outbursts, insolubles, and potash (especially carnallite) have led to the breakage of tubing in a number of caverns, and caused irregular shapes of many caverns through preferential leaching. Such anomalous features essentially have limited the lateral extent of conventional mining at several salt mines, and led to accidents and even the closing of several other mines. Such anomalous features, are often aligned in anomalous zones, and appear to be related to diapiric processes of salt dome development. Evidence indicates that anomalous zones are found between salt spines, where the differential salt intrusion ...

British Library Electronic Table of Contents (United Kingdom)

SnO2/graphene nanocomposites have been fabricated by a simple chemical method. In the fabrication process, the control of surface charge causes echinoid-like SnO2 nanoparticles to be formed and uniformly decorated on the graphene. The electrostatic attraction between a graphene nanosheet (GNS) and the echinoid-like SnO2 particles under controlled pH creates a unique nanostructure in which extremely small SnO2 particles are uniformly dispersed on the GNS. The SnO2/graphene nanocomposite has been shown to perform as a high capacity anode with good cycling behavior in lithium rechargeable batteries. The anode retained a reversible capacity of 634 mA?h?g?1 with a coulombic efficiency of 98% after 50 cycles. The high reversibility can be attributed to the mechanical buffering by the GNS against...

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Severe accident analysis has been performed for the Wolsung nuclear power= plants in Korea to investigate severe accident phenomena of CANDU-600 reactors as a part of Level II PSA study. The accident sequence analyzed in this paper is loss of active heat sinks (LOAH) which is caused by loss of off-site power, diesel generators, and DC power. ISAAC (Integrated Severe Accident Analysis Code) computer code developed by KAERI (Korea Atomic Energy Research Institute) was used in this analysis. This paper describes the important thermal-hydraulics and source term behaviors in the primary system and inside containment, and the failure mechanisms of calandria vessel and containment. In addition, some insights for accident management program (AMP) are also given. (Author) 5 refs., 1 tab., 12 figs.

British Library Electronic Table of Contents (United Kingdom)

Although cognitive performance in humans and experimental animals can be improved by administering omega-3 fatty acid docosahexaenoic acid (DHA), the neurochemical mechanisms underlying this effect remain uncertain. In general, nutrients or drugs that modify brain function or behavior do so by affecting synaptic transmission, usually by changing the quantities of particular neurotransmitters present within synaptic clefts or by acting directly on neurotransmitter receptors or signal-transduction molecules. We find that DHA also affects synaptic transmission in mammalian brain. Brain cells of gerbils or rats receiving this fatty acid manifest increased levels of phosphatides and of specific presynaptic or postsynaptic proteins. They also exhibit increased numbers of dendritic spines on post...

Science.gov (United States)

In this paper we study theoretically a pulsed corona discharge plasma in air at atmospheric pressure. A self consistent one-dimensional model, using a flux-corrected transport numerical scheme, is presented to achieve it. The charged particle kinetics in this model are described by one-dimensional continuity equations coupled with Poisson's equations. The spatio-temporal local field, charge density variations and the velocity profile of an ionizing front are calculated to describe the dynamical behavior of corona discharge plasmas. The simulation results of a wire-in-cylinder corona discharge plasma explain the physical mechanisms of discharge processes. These results may also be apply to obtain the optimizing parameters for designing the plasma reactor.

Energy Technology Data Exchange (ETDEWEB)

The switching behavior of magnetic patterns prepared by ion irradiation was investigated. Co/Pt multilayers with perpendicular anisotropy and large out-of-plane coercivities 5-6 kOe were grown on electron transparent SiN windows. Regularly spaced 1 micron sized regions, were magnetically pattered via ion beam irradiation through a stencil mask. Lorentz TEM was used to observe in-situ magnetization reversal processes of irradiated regions under well-defined applied magnetic fields. When the in-plane field was increased, domain wall motion was observed, resulting in the alignment of the patterns with the direction of the applied field. The switching mechanism of the in-plane patterns was by domain wall motion.

British Library Electronic Table of Contents (United Kingdom)

The interlayer exchange coupling between Co/Pt perpendicular-to-plane magnetized layers across a thin IrMn spacer layer was experimentally studied. In contrast to earlier studies on interlayer coupling through antiferromagnetic NiO, which revealed an oscillatory coupling behavior as a function of NiO thickness, a ferromagnetic coupling was observed here in the range of IrMn thickness between 0.6 and 1.5nm and antiferromagnetic between 1.5 and 2.5nm. The antiferromagnetic coupling is attributed to an orange peel magnetostatic mechanism whereas the ferromagnetic coupling is attributed to an out-of-plane polarization of the antiferromagnetic IrMn layer induced by the interfacial exchange interaction with the adjacent out-of-plane ferromagnetic layers. Measurements of hysteresis loops versus t...

British Library Electronic Table of Contents (United Kingdom)

The behavior of proton transfer facilitated by a novel thiazole derivative, N-methyl-4-(4-phenoxyphenyl)thiazol-2-amine (MPPT), across the water/1,2-dichloroethane (1,2-DCE) interface was investigated electrochemically. The ionic partition diagram for MPPT was obtained from interpretation of the cyclic voltammograms. The apparent partition coefficient of MPPT was evaluated by the shaking-flask method under experimental conditions, while that for the protonated form of MPPT was calculated from its transfer potential obtained from the ionic partition diagram. It was suggested that the mechanism for transfer of MPPT across the water/1,2-DCE) interface depends on the pH of the aqueous phase. The parameters of the facilitated proton transfer across the water/1,2-DCE interface were evaluated as ...

British Library Electronic Table of Contents (United Kingdom)

Experiments of highly subcooled nucleate pool boiling of FC-72 with dissolved air were studied both in short-term microgravity condition utilizing the drop tower Beijing and in normal gravity conditions. The bubble behavior and heat transfer of air-dissolved FC-72 on a small scale silicon chip (10 ? 10 ? 0.5?mm3) were obtained at the bulk liquid subcooling of 41?K and nominal pressure of 102?kPa. The boiling heat transfer performance in low heat flux region in microgravity is similar to that in normal gravity condition, while vapor bubbles increase in size but little coalescence occurs among bubbles, and then forms a large bubble remains attached to the heater surface during the whole microgravity period. Thermocapillary convection may be an important mechanism of boiling heat transfer in ...

International Nuclear Information System (INIS)

AISI 5140 steel was plasma nitrided at various gas mixtures of nitrogen, hydrogen, and argon to investigate the actions of hydrogen and argon on plasma nitriding. The structural and mechanical properties of ion-nitrided AISI 5140 steel have been assessed by evaluating composition of phases, surface hardness, compound layer thickness, and case depth by using X-ray diffraction (XRD), microhardness tests, and scanning electron microscopy (SEM). It was found that the growth of compound layer can be controlled and the diffusion improved when the gas mixture includes H_2 gas. Additionally, it was determined that the amount of Ar in dual gas mixture must be at 20% minimum to obtain distinctive surface hardness and compound layer thickness.

British Library Electronic Table of Contents (United Kingdom)

Ideal free distribution (IFD) models are perhaps the group of mathematical models of behavior that have been the most widely and successfully applied by empiricists. These models can be applied to nearly any situation in which consumers compete?by any mechanism?for resources that are patchily distributed in their environment. Although IFD models have come to be broadly accepted, experiments that simultaneously test more than a single prediction are rare. Instead, investigators normally either test (1) for a relationship between the distribution of consumers and the distribution of resources or (2) whether average fitnesses are equal across resource patches. We conducted experiments with pea aphids (Acyrthosiphon pisum Harris) feeding on two patches of fava beans (Vicia faba L.) to fully in...

British Library Electronic Table of Contents (United Kingdom)

Abstract While the techniques and technologies associated with contaminated sediment remediation are relatively mature, there are several issues associated with these practices that make them unattractive. The inability of currently used mechanical mixing implements to place amendments in aqueous environments and their intrusive behavior toward benthic communities are just two examples of a necessity for an improved delivery method. Waterjets may be a viable option for placement of particulate remediation amendments, such as activated carbon and granular iron, at depth. A custom waterjet nozzle and injection system has been fabricated by the authors to examine this delivery concept. The developed injection system's performance was tested by characterizing the waterjet-delivered amendment (...

British Library Electronic Table of Contents (United Kingdom)

The treatment of Be-contaminated wastewater has been paid little attention, although beryllium (Be) and its compounds are of high toxicity. In this research, aerobic granule was for the first time introduced to remove Be from aqueous solution. Influencing factors including reaction time, initial Be concentration, pH, biosorbent dosage, and coexistent metal ions (Cd, Cu, and Fe) were investigated in batch experiments. The aerobic granule, characterized by element analysis and CLSM, was abundant in carboxyl, phosphoryl, amine and hydroxyl groups. Potentiometric titration experiment demonstrated that the pH effect on biosorption depended on the surface charge of granule (pHzpc=2.4) and the species of Be (Be^2^+, Be(OH)^+, and Be(OH)2) in solution. The coexistent metal ions would either inhibi...

CERN Document Server

Assuming the hoop conjecture in classical general relativity and quantum mechanics, any observer who attempts to perform an experiment in an arbitrarily small region will be stymied by the formation of a black hole within the spatial domain of the experiment. This behavior is often invoked in arguments for a fundamental minimum length. Extending a proof of the hoop conjecture for spherical symmetry to include higher curvature terms we investigate this minimum length argument when the gravitational couplings run with energy in the manner predicted by asymptotically safe gravity. We show that argument for the mandatory formation of a black hole within the domain of an experiment fails. Neither is there a proof that a black hole doesn't form. Instead, whether or not an observer can perform measurements in arbitrarily small regions depends on the specific numerical values of the couplings near the UV fixed point. We further argue that when an ...

British Library Electronic Table of Contents (United Kingdom)

An examination of the kinetics of the alkylation of anisole with 1-hexene and 1-hexanol to produce alkylates over zeolite H-beta is presented. Anisole alkylation is found to occur by a set of parallel reactions when hexene is used as the alkylating agent. When hexyl alcohol is the alkylating agent, the reaction follows a multi-step parallel-series mechanism to form monoalkylates and dihexylether. With 1-hexene, a group of isomeric alkylates, viz., ortho-2-hexyl anisole (2-OHA), ortho-3-hexyl anisole (3-OHA), para-2-hexyl anisole (2-PHA), and para-3-hexyl anisole (3-PHA) was obtained. With hexanol, the olefin (hexene) and dihexyl ether were obtained additionally. The influence of process parameters like temperature, catalyst quantity, and alkylating agent on reaction behavior is reported.

CERN Document Server

The quantum $N$-body problem is studied in the context of nonrelativistic quantum mechanics with a one-dimensional deformed Heisenberg algebra of the form $[\\hat x,\\hat p]=i(1+\\beta \\hat p^2)$, leading to the existence of a minimal observable length $\\sqrt\\beta$. For a generic pairwise interaction potential, analytical formulas are obtained that allow to estimate the ground-state energy of the $N$-body system by finding the ground-state energy of a corresponding two-body problem. It is first shown that, in the harmonic oscillator case, the $\\beta$-dependent term grows faster with $N$ than the $\\beta$-independent one. Then, it is argued that such a behavior should be observed also with generic potentials and for $D$-dimensional systems. In consequence, quantum $N$-body bound states might be interesting places to look at nontrivial manifestations of a minimal length since, the more particles are present, the more the system deviates from ...

International Nuclear Information System (INIS)

In the present study a partial replacement of aggregate with two different ratios of waste rubber (5%, 10%) with the addition of a constant ratio of rice husk ash (RHA), 5% was carried out. The hardened cement mortar used the optimum water of consistency. The specimens were molded into 1 inch cubic moulds .The specimens were first cured for 24 hours, at 100% relative humidity and then cured under tap water for 3, 7 and 28 days followed by irradiation at different doses of gamma irradiation namely 5 and 10 kGy. The physico-chemical and mechanical properties such as compressive strength, total porosity and bulk density were studied for the three types of specimens. The results showed that the values of the compressive strength, bulk density and chemically combined water of the blended cement mortar paste (OPC-RHA) increase ,while blended cement mortar paste with 5% RHA and 5, 10% waste rubber decrease. The results were confirmed by scanning electron microscopy and ...

Energy Technology Data Exchange (ETDEWEB)

In this paper the problem of developing optimal bidding strategies for the participants of oligopolistic energy markets is studied. Special attention is given to the impacts of suppliers' emission of pollutants on their bidding strategies. The proposed methodology employs supply function equilibrium (SFE) model to represent the strategic behavior of each supplier and locational marginal pricing mechanism for the market clearing. The optimal bidding strategies are developed mathematically using a bilevel optimization problem where the upper-level subproblem maximizes individual supplier payoff and the lower-level subproblem solves the Independent System Operator's market clearing problem. In order to solve market clearing mechanism the multiobjective optimal power flow is used with supplier emission of pollutants, as an extra objective, subject to the supplier physical constraints. This paper uses normal ...

International Nuclear Information System (INIS)

4.82 wt% AIN and 2.98 wt% Y_2O_3 were added to Si_3N_4 as sintering agents in order to have #alpha#_Sialon composition of x=0.15 and monoclinic ZrO_2 between 0 to 10 wt% was admixed with Si_3N_4 based ceramics were fabricated by hot-pressing at 1,750 deg C for 90 min under 30 MPa in argon and nitrogen atmospheres effects of sintering atmospheres and addition of ZrO_2 on mechanical properties of Si_3N_4 based ceramics were investigated. As ZrO_2 content increased, the fraction of #alpha#-Sialon tended to decrease and the amount of cubic ZrO_2 increased because Y_2O_3 acted as the stabilizer of ZrO_2. The sintering atmospheres didn't affect on the sintering behavior and the product phases in hot-pressing of Si_3N_4. Bending strength increased when ZrO_2 content. ZrO_2 didn't contribute to the increase of fracture toughness because stabilized cubic ZrO_2 was produced by the added Y_2O_3. (Author).

International Nuclear Information System (INIS)

Acetylcholine and other neurotransmitters play unique trophic roles in brain development. Accordingly, drugs and environmental toxicants that promote or interfere with neurotransmitter function evoke neurodevelopmental abnormalities by disrupting the timing or intensity of neurotrophic actions. The current review discusses three exposure scenarios involving acetylcholine systems: nicotine from maternal smoking during pregnancy, exposure to environmental tobacco smoke (ETS), and exposure to the organophosphate insecticide, chlorpyrifos (CPF). All three have long-term, adverse effects on specific processes involved in brain cell replication and differentiation, synaptic development and function, and ultimately behavioral performance. Many of these effects can be traced to the sequence of cellular events surrounding the trophic role of acetylcholine acting on its specific cellular receptors and associated signaling cascades. However, for chlorpyrifos, additional ...

Energy Technology Data Exchange (ETDEWEB)

For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO{sub 2}, PrO{sub 2}), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two shapes: small cubic (oxide) and large plate-like (tetragonal) structures. The conversion efficiencies of the rare earth elements ...

Energy Technology Data Exchange (ETDEWEB)

The patent is for a method of preparing drilling muds that are notable for their chemical resistance to Zechstein deposits, especially to magnesium, carbonate and carboxylic acid ions. To achieve chemical resistance of the drilling mud to Zechstein deposits, it is suggested to saturate them with salt (the amount of added salt depends on the absorption properties of the solution), and then to process them with caustic soda or potassium oxide hydrate and lime in proportions that would cause filtrate alkalinity not to exceed 0.5. For example, to prepare drilling solution to bore through mediums containing magnesium salts, potassium salts, rock salt, anhydrate, dolomite, limestone, red salt clay: add 340 kg potassium chloride into 1 m/sup 3/ drilling solution with weighed bentonic clay, 10 kg. ferro-chromate lignosulfite, 7 kg. unslaked lime, 2 kg. sodium hydroxide, ...

International Nuclear Information System (INIS)

The static thermodynamic properties of the molten salt system like LiF-NaF-BeF_2 influence the design and construction of the fuel salt and coolant in the Molten Salt Reactor for the new generation. In this paper, the equation of state of the ternary system 15%LiF-58%NaF-27%BeF_2, over the temperature range of 873.15K to 1073.15K at one atmosphere pressure, is described using Peng-Robinson equation modified by us. And the density of the ternary system is evaluated by this equation directly, and compared with the experimental data. Base on the equation of state, the other static thermodynamic properties such as the enthalpy, entropy and heat capacity at constant pressure are estimated by the residual function method and the fugacity coefficient method respectively. The density calculated by Peng-Robinson equation is in highly agreement with the experimental data, and the enthalpy, entropy and heat capacity evaluated by such ...

Energy Technology Data Exchange (ETDEWEB)

Alloy 800 has been proposed for use in the receiver tube panel arrays of advanced solar central receiver (SCR) designs. In this application the alloy will be exposed to a molten mixture of sodium and potassium nitrate salts at temperatures ranging up to approximately 600/sup 0/C While these salts are routinely used in a variety of applications including metal heat treating and process heat transfer, common industrial experience has been limited to maximum temperatures of 400/sup 0/C - 450/sup 0/C. There is, therefore, considerable interest in the compatibility of these salts with containment alloys at the higher temperatures associated with SCR designs. Additionally, the containment alloy may be subject to thermally induced fatigue damage resulting from intermittent cloud cover and diurnal cycling. Previous work has found that slower near-threshold fatigue crack growth rates (FCGR) in Alloy 800 result when it is tested in ...

Science.gov (United States)

With an increased use of fiber reinforced concrete in structural applications, proper characterization techniques and development of design guides are needed. This dissertation presents a multi-scale modeling approach for fiber and fabric reinforced cement-based composites. A micromechanics-based model of the yarn pullout mechanism due to the failure of the interfacial zone is presented. The effect of mechanical anchorage of transverse yarns is simulated using nonlinear spring elements. The yarn pullout mechanism was used in a meso-scale modeling approach to simulate the yarn bridging force in the crack evolution process. The tensile stress-strain response of a tension specimen that experiences distributed cracking can be simulated using a generalized finite difference approach. The stiffness degradation, tension stiffening, crack spacing evolution, and crack width characteristics of cement composites can be derived using ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Energy Technology Data Exchange (ETDEWEB)

Experimental data on the gas holdup and the mean bubble size in a bubble column with a single nozzle was obtained for gas-molten salt systems of a eutectic mixture of LiCl (58 mol %)-KCl (42 mol %) and molten NaNO/sub 3/. The liquid-phase mass transfer coefficient K /SUB L/ was evaluated from the specific surface area a and the volumetric coefficient K /SUB L/ a data for oxygen and carbon dioxide absorption into molten NaNO/sub 3/. The dimensionless correlations of the performance of bubble columns for aqueous solutions can be extended to the gas-molten salt systems.

Energy Technology Data Exchange (ETDEWEB)

Completion of the Phase III evaluation and comparison of salt disposition alternatives was supported with enhanced computer models and analysis for each case on the ''short list'' of four options. SPEEDUP(TM) models and special purpose models describing mass and energy balances and flow rates were developed and used to predict performance and production characteristics for each of the options. Results from the computational analysis were a key part of the input used to select a primary and an alternate salt disposition alternative.

Science.gov (United States)

... taker', Adaptive Behavior. In submission. Behavioral Disorders: Diagnostic Criteria for Re- Breazeal (Ferrell), C. (1998), A Motivational System for ...

British Library Electronic Table of Contents (United Kingdom)

For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO2, PrO2), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two sha...

International Nuclear Information System (INIS)

An oxidative precipitation reaction of rare-earth chlorides in a LiCl-KCl molten salt was successfully carried out by a lab-scale apparatus. The conversion efficiency of the used rare earth chlorides into the insoluble precipitates was increased with the sparging time and temperature and was affected on oxygen sparger type. In the conditions of 700 .deg. C molten salt temperature and above 540min sparging time, the final conversion efficiencies were over 99% for all the experimented rare-earth chlorides. The hydrodynamic characteristics of an oxygen-molten salt two phase flow system are very important for a co-oxidative precipitation of rare earth elements

British Library Electronic Table of Contents (United Kingdom)

The design of a global steady-state thermal model of a 100kWt molten salt cavity receiver was developed as part of the key project of the Ministry of Science and Technology of People's Republic of China (MOST). In the design process, the following factors were analyzed: receiver area, heat loss (convective, emissive, reflective and conductive), number of tubes in the receiver panel, tube diameter and receiver surface temperature. The model was also used to calculate the receiver performance of the Sandia National Laboratories' molten salt electric experiment (MSEE). In addition, the thermal performance of the designed molten salt cavity receiver is presented for a fixed outlet flow rate and a fixed output temperature.

Science.gov (United States)

Adipocyte lipid-binding protein (ALBP or aP2) is an intracellular fatty acid-binding protein that is

International Nuclear Information System (INIS)

Russian 1985. p. 114. USSR Levitskaya, GD Ture, MF Lata, LP L'vovskij

British Library Electronic Table of Contents (United Kingdom)

Normally, concrete technologists attribute salt weathering, salt crystallization or physical attack to the deterioration of concrete that is partially exposed to sulfate environment. However, there are few convincing evidences supporting this view. The purpose of this paper is to check by means of extensive micro-analysis if traces of sulfate crystals are present in the paste. This would enable to verify in a direct way whether salt weathering really causes cement paste damage or not.In this research, cement paste and cement?fly ash paste specimens were partially exposed to sodium sulfate and magnesium sulfates solution under a constant storage condition (20 ? 2 ?C, and 60 ? 5% RH) and a sharply fluctuating environment (40 ? 2 ?C and 35 ? 5% RH for 24 h, then 10 ? 1 ?C and 85 ? 5% RH, also...

Science.gov (United States)

... a given ternary molten salt system under conditions which are greatly " different than the normal method of potentiometric titration, that is, high ...

British Library Electronic Table of Contents (United Kingdom)

The molten salt reactor (MSR), which is one of the generation IV reactors, can meet the demand of transmutation and breeding. The thermodynamic properties of the molten salt system like LiF-NaF-BeF2 influence the design and construction of the fuel salt and coolant in the MSR for the new generation. In this paper, the equation of state of the ternary system 15%LiF-58%NaF-27%BeF2, over the temperature range from 873.15 to 1 073.15 K at one atmosphere pressure, is described using a modified Peng-Robinson (PR) equation. The densities of the ternary system and its components are estimated by this equation directly, and compared with the experimental data. Based on the equation of state, the other thermodynamic properties such as the enthalpy, entropy and heat capacity at constant pressure are ...

Science.gov (United States)

Interactions (FCCI) University of Wisconsin, Madison Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation University of Wisconsin, Madison Next Generation...

Energy Technology Data Exchange (ETDEWEB)

As part of the studies on coal utilization basics, considerations were given on quantification of sulfur forms of coal and the pyrolysis behavior of sulfur compounds. With the temperature raising oxidation method, a thermo-balance was connected directly to a mass analyzer, and the coal temperature was raised at a rate of 5{degree}C per minute and gasified. Peak division was performed on SO2 and COS production to derive sulfur forms of coal. Using the slow-speed pyrolysis method, production rates of H2S, COS, SO2 and mercaptans were measured at a temperature raising rate of 20{degree}C per minute. Sulfur content in char was also measured. With the quick pyrolysis method, a Curie point pyrolyzer was connected directly to a gas chromatograph, by which secondary reaction is suppressed, and initial pyrolytic behavior can be tracked. All kinds of coals produce a considerable amount of SO2 in the slow-speed pyrolysis, but very little in the quick ...

International Nuclear Information System (INIS)

Several Mg-Y binary ribbons with Y content up to #approx#17.9 at.% were fabricated by melt-spinning. X-ray diffraction (XRD) revealed that the phase structure changes with increasing Y content from extended solid solution to partially amorphous, and then fully intermetallic Mg_2_4Y_5. Anodic potentiodynamic polarization performed in 0.01 M NaCl electrolyte (pH=12) revealed improved anodic passivity behavior compared to pure Mg for all the Mg-Y alloys. X-ray photoelectron spectroscopy (XPS) revealed that the improved passivity of Mg-Y was more related to the elemental oxidation state rather than the concentration of the surface components. To study the effect of Cl"- ion on the passivity behavior, anodic potentiodynamic and potentiostatic polarization were performed on Mg-17.9 at.% Y in alkaline (pH=12) NaCl electrolytes containing Cl"- ion in the concentration range from 0.00 to 0.50 M. The passive films formed in 0.01 M NaCl electrolyte were ...

Science.gov (United States)

Extracellular matrix (ECM) comprises a rich meshwork of proteins and proteoglycans, which not only contains biological cues for cell behavior, but is also a reservoir for binding growth factors and controlling their release. Here we aimed to create a suitable bony microenvironment with cell-derived ECM and biodegradable ?-tricalcium phosphate (?-TCP). More specifically, we investigated whether the ECM produced by bone marrow-derived mesenchymal stem cells (hBMSC) on a ?-TCP scaffold can bind bone morphogenetic protein-2 (BMP-2) and control its release in a sustained manner, and further examined the effect of ECM and the BMP-2 released from ECM on cell behaviors. The ECM was obtained through culturing the hBMSC on a ?-TCP porous scaffold and performing decellularization and sterilization. SEM, XPS, FTIR, and immunofluorescent staining results indicated the presence of ECM on the ?-TCP and the amount of ECM increased with the incubation time. ...

International Nuclear Information System (INIS)

Mechanical testing of controlled-purity Ni-xCr-9Fe-yC alloys at 360 C revealed an environmental enhancement in IG cracking and time-dependent deformation in high purity and primary water over that exhibited in argon. Dimples on the IG facets indicate a creep void nucleation and growth failure mode. IG cracking was primarily located at the interior of the specimen and not necessarily linked to direct contact with the environment. Controlled potential CERT experiments showed increases in IG cracking as the applied potential decreased, suggesting that hydrogen is detrimental to the mechanical properties. It is proposed that the environment, through the presence of hydrogen, enhances IG cracking by enhancing the matrix dislocation mobility. This is based on observations that dislocation-controlled creep controls the IG cracking of controlled-purity Ni-xCr-9Fe-yC in argon at 360 C and grain boundary cavitation and sliding results that show the ...

International Nuclear Information System (INIS)

Different SiAlON composites based on #alpha#'-SiAlON are investigated, with respect to the phase relationships, densification behavior, and mechanical properties. The compositions are located on a phase-diagram line parallel to the Si_3N_4-Y_2O_3#centre dot#9AlN compound in the Si_3N_4-SiO_2-AlN-Al_2O_3-Y_2O_3-YN system. Analysis of the reaction sequences shows that the formation of the composites is associated with the transient appearance of Y_4Al_2O_9 (YAM), yttrium-aluminum-garnet (YAG), melilite, and a nitrogen-rich liquid phase. The small shift of compositions on the Si_3N_4-Y_2O_3#centre dot#9AlN compound phase-diagram line toward the Al_2O_3-rich side offers the advantage of a higher sinterability and the removal of the melilite phase from a wide range of compositions containing #alpha#'-SiAlON and polytypes. The #alpha#'/#beta#'-SiAlON composites show better mechanical properties in comparison to pure ...

Energy Technology Data Exchange (ETDEWEB)

X-ray crystal structures of L-3,4-dihydroxy-2-butanone-4-phosphate synthase from Magnaporthe grisea are reported for the E-SO{sub 4}{sup 2-}, E-{sub 4}{sup 2-}-Mg{sup 2+}, E-SO{sub 4}{sup 2-}-Mn{sup 2+}, E-SO{sub 4}{sup 2-}-Mn{sup 2+}-glycerol, and E-SO{sub 4}{sup 2-}-Zn{sup 2+} complexes with resolutions that extend to 1.55, 0.98, 1.60, 1.16, and 1.00 {angstrom}, respectively. Active-site residues of the homodimer are fully defined. The structures were used to model the substrate ribulose 5-phosphate in the active site with the phosphate group anchored at the sulfate site and the placement of the ribulose group guided by the glycerol site. The model includes two Mg{sup 2+} cations that bind to the oxygen substituents of the C2, C3, C4, and phosphate groups of the substrate, the side chains of Glu37 and His153, and water molecules. The position of the metal cofactors and the substrate's phosphate group are further stabilized by an extensive hydrogen-bond and ...

International Nuclear Information System (INIS)

Nitrogen has been added to stainless steels to improve mechanical strength and corrosion resistance. High nitrogen steel production is limited by high gas pressure requirements and low nitrogen solubility in the melt. One way to overcome this limitation is the addition of nitrogen in solid state because of its higher solubility in austenite. However, gas and salt bath nitriding have been done at temperatures around 550 C, where nitrogen solubility in the steel is still very low. High temperature nitriding has been, thus proposed to increase nitrogen contents in the steel but the presence of oxide layers on top of the steel is a barrier to nitrogen intake. In this paper a modified plasma nitriding process is proposed. The first step of this process is a hydrogen plasma sputtering for oxide removal, exposing active steel surface improving nitrogen pickup. This is followed by a nitriding step where high nitrogen contents are introduced in the ...

Energy Technology Data Exchange (ETDEWEB)

The Fredericksberg of South Florida may have a great oil potential that has been overlooked as a primary target in past decades. Previous exploration in the area has targeted the Lower Cretaceous oil-producing Sunniland Formation lower in the stratigraphic section. The Fredericksberg Dollar Bay Formation has hydrocarbon shows in many wells occurring in limestone biohermal deposits as well as in an upper dolomitic section. The Dollar Bay Formation is part of the Big Cypress Group of the Comanchean Series of the Lower Cretaceous. The Lower Cretaceous lithology is composed of evaporitic-carbonate cycles consisting of anhydrites, dolomites, and limestones. There are also present some calcareous shales, mudstones, salt, lignitic material, and carbonaceous material, especially in the anhydrite and limestone intervals. The limestones are usually micritic, chalky, calcarenitic, sometimes argillaceous, containing skeletal particles of gastropods, pelecypods, ostracods, ...

Energy Technology Data Exchange (ETDEWEB)

A solid electrolyte for lithium batteries requires several properties: a good ionic conductivity of about 10{sup -3} S/cm at 298 deg. K, a high cationic transport number (greater than 0.5), a redox stability window higher than 4.5 V, a good stability of the interface with the lithium electrode, and a sufficient mechanical stability. The family of gelled or hybrid electrolytes seems to meet all these requirements. Thus, a systematic study of the gelling of an ethylene carbonate and lithium bistrifluorosulfonimide (LiTFSI) based electrolyte has been carried out. The polymers used for gel or pseudo-gel synthesis are POE, PMMA and PAN which represent 3 different cases of interaction with the electrolyte. All the properties mentioned above have been studied according to the nature of the polymer and to the concentration of lithium salt, showing the advantages and drawbacks of each polymer. The possibility of using some of these gels in lithium-ion ...

Energy Technology Data Exchange (ETDEWEB)

Advanced lithium batteries presently under development operate either at the high temperatures associated with the LiCl-KCl molten salt (350-450/degree/C), or at ambient temperatures employing organic solvent based electrolytes. An intermediate temperature lithium battery is proposed as an alternative if it reduces corrosion problems present at high temperatures and improved kinetic performance with respect to ambient temperature cells. 17 refs.

Energy Technology Data Exchange (ETDEWEB)

A phosphorus-containing low alkali metal content zeolitic catalyst made from a clay starting material is provided. The catalyst is obtained by contacting a partially cation exchanged calcined zeolite-containing catalyst with an anion such as a dihydrogen phosphate anion or a dihydrogen phosphite anion and additionally with an ammonium salt other than a salt of an inorganic acid of phosphorus. A hydrocarbon catalytic cracking process utilizing the phosphorus-containing catalyst is also provided.

Science.gov (United States)

The phytomanagement of Se-polluted soil and water is one strategy that may be environmentally sustainable and cost-effective for soils and waters enriched with natural-occurring Se. Several plant species, including Indian mustard (Brassica juncea), pickleweed (Salicornia bigelovii), and other salt/S...

International Nuclear Information System (INIS)

Distribution of scattered elements in basic minerals of salt-rocks is studied. It is shown that rubidium and cesium are accumulated mainly in carnallites and are contained in small quantities halites. These elements are accumulated primarily in the carnallite production products, wherein their content in a number of cases exceeds by dozens and hundred times their content in source rocks. It is noted that only carnallites may be considered in the list of actual sources for rubidium and cesium separation

Energy Technology Data Exchange (ETDEWEB)

Ammonia is a common and highly toxic pollutant which, in sufficient quantities, will adversely affect aquatic organisms. This ammonia criteria document for salt water will allow establishment of regulatory standards for ammonia discharge into estuaries, near coastal zones and oceans. Possible adverse impacts in highly sensitive and abundant ecosystems such as estuaries make regulation particularly important.

DEFF Research Database (Denmark)

The syntheses of N-alkylated deoxynojirimycin and 1,5-dideoxy-1,5-iminoxylitol derivatives having either a D- or an L-erythritol-3-sulfate functionalized N-substituent are reported. The alkylating agent used was a cyclic sulfate derivative, whereby selective attack of the nitrogen atom at the least hindered primary center afforded the desired ammonium salt. In aqueous solution, these salts were configurationally labile at the ammonium center. Sulfonium and/or selenonium analogues of the ammonium salts were prepared by analogous reactions. The chalcogen salts were obtained as mixtures of diastereomers, separable in some cases, differing only in the stereochemistry at the configurationally stable sulfur or selenium atoms. Proof of configuration and conformation of each compound was obtained by detailed NMR experiments. The compounds are six-membered ring analogues of salacinol, a known ...

Energy Technology Data Exchange (ETDEWEB)

Mixtures of organic-inorganic substances are studied for their performance as energy storage media. Use is made of the fact that organic substances give higher amounts of energy but within a wide range of temperature on the one side and the fact that inorganic substances give lower amounts of energy at constant temperature on the other side. Mixtures of both types of substances, in different ratios, are investigated for the object of determining that optimum composition which stores a higher amount of energy and, meanwhile, releases it at a constant temperature or within a narrow range of temperature. The mixtures used are composed of Glauber`s salt (Na{sub 2}SO{sub 4}.10H{sub 2}O) and stearic acid in different proportions. The effect of cooling fluid flow rate and ambient temperature as well as the effect of addition of a nucleating agent is studied. The results showed that the highest amount of energy stored could be obtained from a mixture containing 40% stearic ...

British Library Electronic Table of Contents (United Kingdom)

Homozygous transgenic cotton (Gossypium hirsutum L.) plants that accumulated glycinebetaine (GB) in larger quantities were more tolerant to salt than wild-type (WT) plants. Four transgenic lines, namely 1, 3, 4, and 5, accumulated significantly higher levels of GB than WT plants did both before and after salt stress. At 175 and 275?mM NaCl, seeds of all the transgenic lines germinated earlier and recorded a higher final germination percentage, and the seedlings grew better, than those of the WT. Under salt stress, all the lines showed some characteristic features of salt tolerance, such as higher leaf relative water content (RWC), higher photosynthesis, better osmotic adjustment (OA), lower percentage of ion leakage, and lower peroxidation of the lipid membrane. Levels of endogenous GB in ...

British Library Electronic Table of Contents (United Kingdom)

Soils of arid regions of Central Asia contain salts of different types that may differentially affect seed germination and plant development. We studied effect of NaCl, Na2SO4, 2NaCl + KCl + CaCl2 and 2Na2SO4+K2SO4+MgSO4 on germination of Kochia prostrata and Kochia scoparia seeds under a range of concentrations from 0.5 to 5% and at two constant temperature regimes +22 degrees C and +6 degrees C. The observed salt tolerance limit of germination at constant temperature +22 degrees C for both species was 5-6%, while at low temperature (+6 degrees C) this limit was 2%. The salt tolerance of young plants (before flowering) was 3% for NaCl. Low concentrations of sulfuric and mixed salts had a stimulating effect on seed germination in K. prostrata. Despite similarity of salt-tolerance limits...

Energy Technology Data Exchange (ETDEWEB)

Six safety initiatives have been identified for accelerating the resolution of waste tank safety issues and closure of unreviewed safety questions. Safety Initiative 5 is to reduce safety and environmental risk from tank leaks. Item d of Safety Initiative 5 is to complete corrosion studies of single-shell tanks to determine failure mechanisms and corrosion control options to minimize further degradation by June 1994. This report has been prepared to fulfill Safety Initiative 5, Item d. The corrosion mechanisms that apply to Hanford Site single-shell tanks are stress corrosion cracking, pitting/crevice corrosion, uniform corrosion, hydrogen embrittlement, and microbiologically influenced corrosion. The corrosion data relevant to the single-shell tanks dates back three decades, when results were obtained from in-situ corrosion coupons in a few single-shell tanks. Since that time there have been intertank transfers, evaporation, and chemical ...

Science.gov (United States)

Pentaerythritol tetranitrate (PETN) is a relatively sensitive explosive used in many electroexplosive devices as well as in medicine. Of primary interest to LLNL is its use in items such as exploding bridgewire (EBW) detonators and exploding bridge foil initiators (EFI). In these devices the crystalline powder is pressed into a granular, low-density compact that can be initiated by an exploding wire or foil. The long-term stability of this pressed compact is of interest to weapon stockpile lifetime prediction studies. Key points about potential aging mechanisms can be summarized as follows: (1) There are a number of factors that can contribute to PETN instability. These include particle size, polymorphic phase transitions, crystal structure, impurities, moisture, occlusions, chemical incompatibility and biological (microorganism) action. of these factors the most important for long-term aging of high surface area powders used in detonators appears to be that of ...

UK PubMed Central (United Kingdom)

Dependent variables in research on problem behavior typically are based on measures of response repetition, but these measures may be problematic when behavior poses high risk or when its occurrence...Full Text Available

UK PubMed Central (United Kingdom)

The ventromedial hypothalamus (VMH) plays a central role in the regulation of the female reproductive behavior lordosis, a behavior dependent upon the sequential activation of receptors for the ovarian...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This article concerns the synergetic effects between an MoO{sub 3} sample composed of crystallites exposing preferentially the (010) basal faces and {alpha}-Sb{sub 2}O{sub 4} in the oxygen-assisted dehydration of 2-butanol at 220 C. The conversion of 2-butanol and the yield to butene improved when MoO{sub 3} was reacted in the presence of {alpha}-Sb{sub 2}O{sub 4}. The origin of the synergism is discussed. When reacted in the absence of {alpha}-Sb{sub 2}O{sub 4}, MoO{sub 3} got over-reduced and fragmented to MoO{sub 2}. MoO{sub 2} is intrinsically less active than MoO{sub 3} thus explaining that the deep reduction of MoO{sub 3} corresponds to its tendency to deactivate. In the presence of {alpha}-Sb{sub 2}O{sub 4}, the formation of MoO{sub 2} is inhibited with, as a consequence, the absence of deactivation. This leads to the synergetic effects obtained with the mechanical mixture of MoO{sub 3} with {alpha}-Sb{sub 2}O{sub 4}. (orig.)

International Nuclear Information System (INIS)

In a breeder-type nuclear power plant, liquid metal is used as a coolant due to the high heat capacity factor. Also, some proposals for fusion reactor blanket design include liquid metal as a possible coolant. In both cases the understanding of natural circulation of liquid-metal flow behavior is an integral part of the thermal hydraulic analysis, especially under two-phase flow conditions. Experimental investigations have been conducted to study a liquid metal two-phase natural circulation flow system. A lead-bismuth (PbBi) eutectic mixture is used as a working fluid in a heated metal walled natural circulation loop. Gas injection induces natural circulation through the gas-lift mechanism. A real-time neutron radiography system is used to visualize the two-phase mixture, specifically the interface and the flow regime. Measurements of void fraction, void fluctuation and bubble propagation are performed.

Scientific Electronic Library Online (English)

Abstract in english Cytokines are molecules that were initially discovered in the immune system as mediators of communication between various types of immune cells. However, it soon became evident that cytokines exert profound effects on key functions of the central nervous system, such as food intake, fever, neuroendocrine regulation, long-term potentiation, and behavior. In the 80's and 90's our group and others discovered that the genes encoding various cytokines and their receptors are e (more) xpressed in vascular, glial, and neuronal structures of the adult brain. Most cytokines act through cell surface receptors that have one transmembrane domain and which transduce a signal through the JAK/STAT pathway. Of particular physiological and pathophysiological relevance is the fact that cytokines are potent regulators of hypothalamic neuropeptidergic systems that maintain neuroendocrine homeostasis and which regulate the body's response to stress. The ...

International Nuclear Information System (INIS)

An alloy of composition Ti-4.4 wt.% Ta-1.9 wt.% Nb is being developed as a structural material for corrosion applications, as titanium and its alloys possess excellent corrosion resistance in many oxidizing media. The primary physical metallurgy database for the Ti-4.4 wt.% Ta-1.9 wt.% Nb alloy is being presented for the first time. Determination of the #beta# transus, M_s temperature and classification of the alloy have been carried out, employing a variety of microscopy techniques, X-ray diffraction (XRD), micro-hardness and differential scanning calorimetry (DSC). The #beta# transition temperature or #beta# transus determined using different experimental techniques was found to agree very well with evaluations based on empirical calculations. Based on chemistry and observed room temperature microstructure, the alloy has been classified as an #alpha# + #beta# titanium alloy. The high temperature #beta# transforms to either #alpha#' or #alpha# + #beta# by a martensitic or ...

Energy Technology Data Exchange (ETDEWEB)

A stochastic-convective reactive (SCR) transport method is developed for one-dimensional steady transport in physically heterogeneous media with nonlinear degradation. The method is free of perturbation amplitude limitations and circumvents the difficulty of scale dependence of phenomenological parameters by avoiding volume-averaged specifications of diffusive/dispersive fluxes. The transport system is conceptualized as an ensemble of independent convective-reactive streamlines, each characterized by a randomized convective velocity (or travel time). Dispersive effects are treated as a component of the randomness in the streamline velocity ensemble, so no explicit expression for hydrodynamic dispersive flux is written in the streamline transport equation. The expected value of the transport over the stream tube ensemble is obtained as an average of solutions to the reactive convection equation according to the stream tube (travel time) probability distribution function. In this way, ...

Energy Technology Data Exchange (ETDEWEB)

A comprehensive experimental program on pullout tests of steel fibers from cement based matrices is described. A specially designed single fiber pullout apparatus was used to provide a quantitative determination of interfacial properties that are relevant to toughening brittle materials through fiber reinforcement. The parameters investigated included a specially designed high strength cement based matrix called Densified Small Particles system (DSP), a conventional mortar matrix, fiber embedment length, and the fiber volume fraction. The mediums from which the fiber was pulled included a control mortar mix without fibers, a mortar mix with 3, and 6 percent fibers by volume. The results indicate that: (1) the dense DSP matrix has significantly improved interfacial properties as compared to the conventional mortar matrix. (2) Increasing the fiber embedment length and the fiber volume fraction in the cement matrix increase the peak pullout load and the pullout work. (3) The major bond ...

International Nuclear Information System (INIS)

The dependence of the photoluminescent properties of In_0_._4_8(Al_yGa_1_-_y)_0_._5_2P alloys (0#<=#y#<=#0.5) on growth temperature and substrate misorientation off GaAs(100) has been studied. Samples were grown using low-pressure metalorganic vapor phase epitaxy. By studying the dependence of ordering behavior in InGaP as a function of substrate misorientation and growth temperature simultaneously, a very large range in low-temperature photoluminescence emission energy---135 meV---has been obtained. The photoluminescence linewidth exhibits a strong, continuous dependence on the extent of atomic ordering (the emission energy) in the alloys. The results indicate that inhomogeneity in the microstructure of the material (i.e., between ''ordered'' domains and the ''disordered'' matrix) is the dominant photoluminescence broadening mechanism. This investigation has allowed a significant optimization of the optical properties of these materials, ...

Energy Technology Data Exchange (ETDEWEB)

The goal of this project is to improve energy efficiency of industrial crushing and grinding operations (comminution). Mathematical models of the comminution process are being used to study methods for optimizing the product size distribution, so that the amount of excessively fine material produced can be minimized. The goal is to save energy by reducing the amount of material that is ground below the target size, while simultaneously reducing the quantity of materials wasted as ''slimes'' that are too fine to be useful. This is being accomplished by mathematical modeling of the grinding circuits to determine how to correct this problem. The approaches taken included (1) Modeling of the circuit to determine process bottlenecks that restrict flowrates in one area while forcing other parts of the circuit to overgrind the material; (2) Modeling of hydrocyclones to determine the mechanisms responsible for retaining fine, ...

Energy Technology Data Exchange (ETDEWEB)

The reactions between (100) GaAs and the near-noble metals Ni, Pd, and Pt have been investigated by application of high-resolution transmission electron microscopy (TEM), energy-dispersive analysis of x rays in the scanning TEM and Rutherford backscattering spectrometry. Emphasis is placed on the evolution of the phase distributions, film compositions, and interface morphologies during annealing at temperatures up to 480 /sup 0/C. The first phase in the Ni/GaAs reaction is shown to have the nominal composition Ni/sub 3/GaAs. Ternary phases of the type Pd/sub x/GaAs are also found to be the dominant products of the Pd/GaAs reaction. Conversely, only binary phases result from the Pt/GaAs reaction. These observations are used to construct isothermal sections of the M--Ga--As thin-film phase diagrams. The behavior of a thin (1--2 nm) native oxide--hydrocarbon layer during the Ni/GaAs, Pd/GaAs, and Pt/GaAs reactions is also investigated. Only the Ni/GaAs reaction is ...

Energy Technology Data Exchange (ETDEWEB)

The microstructural development and grain-coarsening behavior of WC-Co alloys, with and without a VC additive, were investigated. The primary goal was to determine the mechanism through which VC acts as a grain-growth inhibitor. The study involved long-time sintering experiments (1 to 100 hours) on fully dense material, nascent stage sintering (90 to 1,320 seconds) starting with the green compact, and surrogate liquid phase experiments to characterize the WC powder prior to sintering. Quantitative microstructural analysis using intercept length distributions was performed for the long-term sintering. The nascent stage experiments involved the measurement of the specific surface area (S{sub v}) of each type of interface separately allowing the determination of the contribution of each developing entity to the overall microstructural evolution. The VC addition has been found to enhance the breakup of multigrained particles in the earliest stages ...

Energy Technology Data Exchange (ETDEWEB)

Alumina (94 and 99.8% grade compositions) was brazed directly to itself with gold-based active brazing alloys (ABA's) containing vanadium additions of 1,2 and 3 weight percent. The effects of brazing conditions on the joint properties were investigated. Wetting behavior, interfacial reactions, microstructure, hermeticity and tensile strength were determined. Wetting was fair to good for the ABA and base material combinations. Microanalysis identified a discontinuous Al-V-O spinel reaction product at the alumina-braze interface. Tensile strength results for 94% alumina were uniformly good and generally not sensitive to the vanadium concentration, with tensile values of 85-105 MPa. There was more variability in the 99.8% alumina strength results, with values ranging from 25-95 MPa. The highest vanadium concentration (3 wt. %) yielded the highest joint strength for the brazed 99.8% alumina. Failures in the 99.8% alumina samples occurred at the braze-alumina ...