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A microanalytical characterization of cast magnesium alloys of eutectic origin based on the Mg?Al?Ca ternary matrix system has been carried out in order to investigate the influence of alloying elements on their microstructure as well as microchemistry-processing-microstructural relations using structure-sensitive techniques of electron microscopy, mechanical spectroscopy (internal friction), X-ray diffractometry, and advanced microanalytical methods including electron probe compositional analysis. Following the data obtained here there is direct correlation of microstructure with creep properties of the new experimental magnesium alloys. The creep and heat-induced properties of the multicomponent magnesium alloys containing low range of inexpensive additions of titanium (0.07?0.2%) or str...

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... Both magnesium and aluminium phosphides are therefore potentially more efficient than either calcium or sodium phosphide. ...

British Library Electronic Table of Contents (United Kingdom)

In the present study, new light weight nano-composites (AZ31B-3.3Al2O3-Cu) based on magnesium alloy AZ31B are developed using disintegrated melt deposition technique. Microstructural characterization studies revealed grain refinement and significant increase in amount of second phases as a result of increasing presence of copper. All the samples exhibited minimal porosity and good matrix-second phase interfacial integrity. The results also showed that addition of both nano-Al2O3 and Cu led to a simultaneous improvement in 0.2% yield compressive strength (0.2%YCS), ultimate compressive strength (UCS) and work of fracture (WoF) of the AZ31B magnesium alloy while failure strain was marginally affected. The results of this study clearly illustrate the capability of AZ31B-Al2O3-Cu formulations ...

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This patent describes a catalyst composition. It consists of the catalytic oxides of iron, bismuth, molybdenum and magnesium as essential components and optionally the oxides of cobalt, nickel, phosphorus and arsenic.

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... BUCKLING ANALYSIS OF METAL MATRIX COMPOSITE SANDWICH PANELS UNDER DIFFERENT THERMAL ENVIRONMENTS , Technical Memorandum ...

British Library Electronic Table of Contents (United Kingdom)

The effect of particle/matrix interface debonding on composites consisting of elastic particles and viscoelastic matrix is studied. The interface debonding is represented by a nonlinear cohesive law for the high explosive PBX 9501. The Mori-Tanaka method gives the constitutive relation of the composite in terms of the properties of elastic particles, viscoelastic matrix, and nonlinear cohesive law for interfaces. For the example of a composite with spherical particles subject to hydrostatic tension, simple analytical expressions of the composite stress-strain relation are obtained. The strain rate and temperature have strong effects on the composite behavior. High strain rate and low temperature give high strength of the composite. However, the rate and temperature effects decrease as the ...

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The catalytic effects of copper-aluminium-magnesium oxides in the oxidative coupling of phenylethyne is described. The importance of surface properties as a redox site are discussed.

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The Cu- and Ni-based bulk metallic glass matrix composites were fabricated by spark plasma sintering of a mixture of gas-atomized metallic glass powders and ductile brass powders. The brass powders added for the enhancement of plasticity are well distributed in the matrix after consolidation. The matrix of the composite materials remains as a fully amorphous phase after consolidation process. With increasing the brass content, the level of plasticity strain increased, although the level of strength decreased. The successful consolidation of metallic glass matrix composite with high density was attributed to viscous flow in the supercooled liquid state during spark plasma sintering.

International Nuclear Information System (INIS)

Hybrid organic-inorganic coatings with phosphonate functionalities have been synthesized and evaluated as prospective surface treatments for magnesium materials. These coatings have been processed via a sol-gel route by hydrolysis and condensation of a mixture of diethylphosphonatoethyltriethoxy-silane and tetraethoxy-silane with variable molar ratios. The coatings morphology and the surface chemistry at the coating/substrate interface have been characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, "3"1P nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry. The corrosion protection performance of the coatings deposited on magnesium alloy AZ31B has been examined by a group of electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, a scanning Kelvin probe technique has been used to investigate interfacial ...

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A composite is any combination of two or more resources held together by some type of mastic or matrix. This report will describe several different types of composites with regard to thermoplasticization, improved mechanical properties, and stiffness.

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The microstructure of the interphase in semicrystalline polymer matrix composites has a dramatic influence on their mechanical properties. Studies have been performed to alter this region and to correlate various interphase morphologies with changes in fiber-matrix adhesion. A reinforced nylon 66 composite, when subjected to specific thermal histories, contains an interphase composed of transcrystallinity. This region has been altered by coating fibers with a diluent, poly(vinyl pyrrolidone), and/or adding the diluent to the matrix material in very small quantities. Interphase morphology was investigated with optical microscopy, and adhesion was measured using a modified fiber pull-out test. It was found that transcrystallinity increases the interfacial shear strength. The effect different interphase morphologies have on the durability of bulk composite samples ...

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The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically 'hard' deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

Science.gov (United States)

curves are also directly translatable to metal-matrix composites. ..... 4~f4'4 ..... result of learning curve. The most important reduction in cost as a ...

British Library Electronic Table of Contents (United Kingdom)

Wood plastic composites (WPCs) are comprised of wood flour and thermoplastic polymer. The matrix is typically high-density polyethylene, poly (vinyl chloride), or polypropylene. The effect of morphology and micromechanics of wood flour particles on the mechanical performance of the bulk composite is a relatively unexplored area. The knowledge about the in situ properties of wood particles and the interfacial properties between the wood particles and the polymer matrix in the bio-composites is very limited. The objective of this work is to characterize the full-field deformation and strain distribution in and around wood particles embedded in polymer matrix. The mechanical tests are performed in small-scale tensile loading stage on thin composite samples containing 1-3 wood particles orient...

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A variety of engineering and experimental applications require primary support structures which are self-centering. High mechanical strength, low-density, carbon fiber/epoxy matrix composite springs are used in unique planar, cylindrical, conical, and spherical configurations to self-center components. The sinusoidal and triangular-shaped composite springs are readily manufactured and assembled into component hardware. Design considerations, flexural strength properties, load bearing and centering data plus procedures for the manufacture of composite springs are presented.

British Library Electronic Table of Contents (United Kingdom)

A viscoelastically prestressed polymeric matrix composite (VPPMC) is produced by applying tension to polymeric fibres, the tensile load being released prior to moulding the fibres into a matrix. Following matrix solidification, compressive stresses imparted by the viscoelastically strained fibres improve composite tensile, flexural and impact properties. This study focuses on the potential for useful life and impact protection capability by performing Charpy impact tests on nylon 6,6 fibre-polyester resin samples subjected to accelerated ageing. Prior to testing, time-temperature superposition principles were used, the samples being aged by heating to 60degreeC for periods representing a 10-fold increase over previous work. The results demonstrated no deterioration in impact performance ov...

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Quasi-carbon fibers (QCFs) were prepared from Polyacrylonitrile (PAN) precursor by pyrolysis in the temperature range from 400{degrees}C to 950{degrees}C. The QCF-reinforced composites were fabricated by impregnating the QCFs with the PAN resin. The microstructural changes of both QCFs and their composites were characterized by the X-ray diffraction method. The stacking size and the crystallinity of the QCFs increased with the increasing heat treatment temperature (HTT). The crystallinity of the PAN matrix in a composite was also affected by various QCFs. DSC data indicated that thermal reaction mechanism of the composite could be altered due to the interaction between the fiber and the matrix. DMTA studies showed that good adhesion existed at the interface of the QCF-reinforced composites containing lower HTT fibers. The modulus magnitudes ...

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The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO{sub 2} and fertilization (two CO{sub 2} treatments, elevated CO{sub 2} and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO{sub 2} enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO{sub 2} and N fertilization amplified some element unbalances such ...

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 ...

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A composite material consisting of WC-Co particles in a steel matrix was fabricated by sintering mixtures of WC-Co particles and a steel powder and infiltrating the sintered pieces with a copper alloy. Its wear resistance and mechanical properties were studied as a function of the content in WC-Co particles and other characteristics of the composite material microstructure. Infiltration provided a simple means to obtain a strong cohesion between WC-Co particles and the steel matrix. An effective matrix protection against wear is obtained with relatively low additions of particles especially with a silica abrasive which is soft with respect to cemented carbide. The experimental results show that this material has good mechanical properties and wear resistance. Depending upon abrasion resistance, wear losses are reduced up to 10 times by a 30 vol% addition of cemented carbide ...

British Library Electronic Table of Contents (United Kingdom)

The electroless nickel plating/poly(dl-lactide-co-glycolide) composite coating (EN-plating/PLGA composite coating) was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy AZ81 to double control the corrosion and drug release in the hanks' solution. The EN-plating was fabricated on the MAO coating to improve the corrosion resistance by overlaying most pores and micro-cracks on the surface of the MAO film. Meanwhile, a double layered organic poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) drug releasing coating with a top layered PLGA drug controlled releasing coating on EN plating was prepared to control the drug release rate by adjusting the different lactide: glycolide (LA:GA) ratio of PLGA. Scanning electron microscopy (SEM) and the X-ray powder dif...

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The purpose of the present work is to investigate the effects of matrix resin and fiber content on the behavior of fatigue crack propagation in continuous-glass-fiber-mat reinforced CP-resin composites. For this purpose, ductile matrix resin and brittle one are used. These two kinds of resins have the characteristic that the elastic modulus and tensile strength are nearly the same with each other while the elongation is different. The composite specimens are made of these resins and continuous grass fiber mat of 20 wt.% and 60 wt% fiber contents. The fatigue crack propagation test was conducted by using the tapered DCB specimens to control the stress intensity factor range, {delta}K, during the test. The results obtained are as follows; (1) The relation between the crack propagation rate, da/dN, and {delta}K for all the present materials is shown by a straight line in logarithmic representation. (2) For ...

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The effect of interfacial structure on the mechanical properties of aluminum-ceramic composite materials fabricated by liquid phase sintering was studied. The composites were based on two matrix alloys (powder metallurgy alloys 201 and 601) reinforced with either Al{sub 2}O{sub 3} or SiC particulate. Characterization of the interfacial regions demonstrated that the SiC-matrix interfaces were faceted whereas the Al{sub 2}O{sub 3}-matrix interfaces had an incomplete layer of a silicon-rich amorphous phase. Preferential attack of the particles during sintering is believed to cause the crystallographic facets to form on SiC. Locally high silicon concentrations near Al{sub 2}O{sub 3} particles led to the formation of a glassy phase from the reduction of Al{sub 2}O{sub 3}. The difference in interfacial structure resulted in a higher particle-matrix bond strength and ...

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In this work, an attempt was made to develop a novel type of wear-resistant composite employing a TiNi alloy matrix reinforced by hard particles. Titanium carbide was chosen as the reinforcing phase because of its high hardness and TiNi alloy as the matrix due to its pseudoelasticity and good toughness. TiC particles may sustain external load, while the TiNi matrix may accommodate deformation, absorb impact energy and retain the hard particles. Such a combination is expected to lead to an enhanced wear resistance, compared to TiNi alloy. As a matter of fact, some efforts were previously made to develop TiNi-matrix composite reinforced by ceramic particles. However, the emphasis of those studies was put on effects of the reinforcing particles on the phase transformation behavior, shape memory effect and some mechanical properties of the ...

Science.gov (United States)

Continuous wave lasing operation with the shortest wavelength for semiconductor lasers was obtained from AlGaInP double heterostructure lasers at 77 K. The structure was grown by metalorganic vapor phase epitaxy. Lasing wavelength was 583.6 nm (yellow). Threshold current was 43 mA (1.9 kA/cm/sup 2/). Magnesium was adopted as a p-type dopant, and was proved to be preferable for a high aluminum composition AlGaInP cladding layer.

International Nuclear Information System (INIS)

Optimum processing parameters were searched for the pilot-scale production of wood-polyester composites by irradiation of resin-impregnated wood material. The radiation initiation of the following systems were examined in wood and without wood matrix: methyl methacrylate, mixture of styrene and acrylonitryle, and their combination with unsaturated polyester. In the most cases the over-all rate of the complete polymerization process in wood matrix is proportional to the square root of the initiation rate. The parameters of the radiation technology of wood-polyester composites have been determined, using 260 TBq (7 kCi) "6"0Co radiation source. A pilot plant has been constructed using an underwater irradiation system of 1.85 PBq (50 kCi) "6"0Co. The successful production rate of 200 kg wood-polyester composite per day, as well as the application tests have demonstrated the technical ...

British Library Electronic Table of Contents (United Kingdom)

In the present paper, the effects of hydroxyapatite (HA) content on the microstructure, thermal and mechanical properties of Ti-based glassy alloy/HA composite prepared by spark plasma sintering (SPS) are investigated. The microstructure of the composites is homogeneous when the HA is lower than 2 wt%. When the HA content is higher than 3 wt%, the crystalline precipitates with size of less than 5 nm are distributed in the glassy matrix. HA decomposes during sintering procedure for the composite with high HA content. With increasing HA addition, compressive strength decreases. Especially for the HA content is over 2 wt%, the strength decreases sharply because of partial crystallization of glassy alloy matrix.

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Plastic composites have become a large class of construction material for exterior applications. One of the main disadvantages of wood plastic composites resides in the weak adhesion between the polar and hydrophilic surface of wood and the non-polar and hydrophobic polyolefin matrix, hindering the dispersion of the flour in the polymer matrix. To improve interfacial compatibility wood flour can be pretreated with environmentally friendly methods such as cold-atmospheric pressure plasma. The objective of this work is therefore to evaluate the potential of plasma polymerization of acetylene on wood flour to improve the compatibility with polyolefins. This presentation will describe the reactor design used to modify wood flour using acetylene plasma polymerization. The optimum conditions for plasma polymerization on wood particles will also be presented. Finally preliminary results on the wood flour ...

Science.gov (United States)

Titanium metal-matrix composites (MMC) are prime candidate materials for aerospace applications be-cause of their excellent high-temperature longitudinal strength and stiffness and low density compared with nickel- and steel-base materials. This article examines the steps GE Aircraft Engines (GEAE) has taken to develop an induction plasma deposition (IPD) processing method for the fabrication of Ti6242/SiC MMC material. Information regarding process methodology, microstructures, and mechani-cal properties of consolidated MMC structures will be presented. The work presented was funded under the GE-Aircraft Engine IR & D program.

International Nuclear Information System (INIS)

The physical, chemical and mechanical properties of magnesium alloys make them attractive materials for automotive and aerospace applications. However, these materials are susceptible to corrosion and wear. This work discusses the potential of using sol-gel based coatings consisting of ZrO_2 and 15 wt.% of CeO_2. The CeO_2 component provides enhanced corrosion protection, while ZrO_2 impart corrosion as well as wear resistance. Coating deposition was performed by the dip coating technique on two magnesium alloy substrates with different surface finishes: AZ91D (as-casted, sand-blasted, and machined) and AZ31 (rolled and machined). All as-deposited coatings (xerogel coatings) were then subjected to 10 h annealing: a temperature of 180 C was applied to the AZ91D alloy and 140 C to the AZ31 alloy. Morphological and structural properties of the annealed coatings were investigated by scanning electron microscopy, atomic force microscopy and ...

British Library Electronic Table of Contents (United Kingdom)

Mineral carbonation is based on the reaction of carbon dioxide with metal-oxide bearing minerals, usually containing magnesium or calcium silicate, to form hardly soluble carbonates and other solid byproducts. The concept is based on acceleration of the naturally occurring rock weathering process. In the present work the calcium silicate is present in the mineral, wollastonite. To accelerate the process and make it potentially useful for practical applications, mineral carbonation is conducted here using an indirect two-step route in which the reactive component (Ca^2^+ ions in considered case) is first extracted from the mineral matrix and afterwards carbonated. Two solid byproducts are formed in this process: silica in the extraction step and calcium carbonate in the carbonation step. In...

International Nuclear Information System (INIS)

By means of the light microscopy and by the measurement of the mechanical properties one investigated into the phase composition and the properties of Al-Mg-Ce and Al-Mg-Y system alloys. One plotted the isothermal cross sections of the mentioned systems under 430 and 275 deg C temperatures at up to 16% magnesium concentration and up to 0.7% yttrium concentration. One determined the yield limit and strength, the relative elongation of Al-Mg base hardened and deformed alloys containing 7.0-9.9% Mg and Ce, Y, Mn, Zr dopes upon ageing under 175, 200, 250 and 300 deg C temperatures within the ageing time ensuring the hardening maximum effect

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In this study, silver nanoparticles were formed on a natural macroporous matrix, the stem of rice-paper plant, by reducing Ag{sup +} in aqueous solution through in situ processing without using any other stabilizers. The pores of the matrix, with their size of about 100 {mu}m, were thought to act as reaction compartments for the nucleation and growth of silver nanoparticles, and the control of nucleation of silver crystal during the reduction reaction was found to be important to the successful formation of nanosized silver particles onto the matrix. The diameter and amount of resultant silver particles can be controlled by changing the reaction conditions. Under optimized conditions, the content of silver particles in the matrix can reach as high as 1.8 wt% with the particle diameters being kept below 100 nm. The anti-microbial activities in terms of minimum inhibitory concentration (MIC) for the ...

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INTRODUCTION. We searched for a pathophysiologically based feature of major water electrolytes, which may define water quality better than the water hardness, respecting urinary calculus formation. MATERIALS AND METHODS. Utilizing a multistage stratified sampling, 2310 patients were diagnosed in the imaging centers of the provincial capitals in Iran between 2007 and 2008. These were composed of 1755 patients who were settled residents of 24 provincial capitals. Data on the regional drinking water composition, obtained from an accredited registry, and their relationships with the region's incidence of urinary calculi were evaluated by metaregression models. The stone risk index (defined as the ratio of calcium to magnesium-bicarbonate product in drinking water) was used to assess the risk of calculus formation. RESULTS. No correlation was found between the urinary calculus incidence and the amount of calcium, bicarbonate, or the total hardness ...

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Recent developments on plastic forming technology of magnesium alloys are presented. Attempts have been undergoing with an aim at forming magnesium alloy parts at lower temperatures. It is believed that fine microstructure magnesium alloys usually have much higher plasticity at lower temperatures and even room temperatures. Extrusion is a method to form magnesium profile products and tube products, which is also one of the effective ways to make fine microstructure magnesium alloys. Superplasticity forming is another method to form high plasticity magnesium alloys. Hot forming of magnesium sheet parts is an important process to form magnesium products. Some developments related to above issues are discussed in the present paper. (orig.)

International Nuclear Information System (INIS)

There is growing interest in the use of natural fibres as the reinforcements for polymer composites in the automotive industry and as matrix for composites in building products application to replace synthetic fibres. In this respect the aim of this study is to develop an environmental friendly composites for furniture industry based on EFB fibres and sago starch. In this preliminary study, a basic composition and processing of EFB fibres-sago starch composites were established and the properties of the composites were determined. EFB fibre content was varied between 50-80% by weight. The amount of sago starch in liquid form was also varied and final weight percentage of sago starch added into the EFB fibres was adjusted accordingly. The mixtures of EFB fibres and sago starch were blended using Haake Rheomixer. The preliminary results ...

UK PubMed Central (United Kingdom)

Fasting plasma concentrations of magnesium were measured by neutron activation analysis in 30 non-diabetics and 87 diabetics (55 non-insulin-treated, 32 insulin treated). Plasma concentrations of magnesium...Full Text Available

International Nuclear Information System (INIS)

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si"2"+, 1.0-MeV He"+ and 340-keV H"+) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by ...

Science.gov (United States)

The variation of metallic particle size and sample porosity significantly alters the dynamic mechanical properties of high density granular composite materials processed using a cold isostatically pressed mixture of polytetrafluoroethylene (PTFE), aluminum (Al), and tungsten (W) powders. Quasistatic and dynamic experiments are performed with identical constituent mass fractions with variations in the size of the W particles and pressing conditions. The relatively weak polymer matrix allows the strength and fracture modes of this material to be governed by the granular type behavior of agglomerated metal particles. A higher ultimate compressive strength was observed in relatively high porosity samples with small W particles compared to those with coarse W particles in all experiments. Mesoscale granular force chains of the metallic particles explain this unusual phenomenon as observed in hydrocode simulations of a drop-weight test. Macrocracks ...

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Gas and plasma nitriding processes were executed in the magnesium with modification by titanium in search for an effective surface treatment method for magnesium alloys. Magnesium-nitrogen system has completely no solid solution or solubility, so that nitride should be only formed by eutectic reaction in the liquid phase. Hence, magnesium is difficult or nearly impossible to have its surface modified by nitriding. Addition of nitride forming element into magnesium enables us to lower the onset temperature of nitriding. Magnesium-titanium alloys with 1 to 5 wt% are yielded by the bulk mechanical alloying and, subjected to gas nitriding for various process conditions. Successful co-formation of Mg{sub 3}N{sub 2} as well as TiN becomes a proof to demonstrate the possibility of gas/plasma nitriding in the solid-state magnesium with aid of ...

International Nuclear Information System (INIS)

The microstructure of commercial rolled magnesium alloy AZ31B (nominal composition Mg-3Al-0.9Zn-0.15Mn in wt.%) was investigated with the help of light microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction technique after annealing in the temperature range from room temperature (RT) to 400 deg. C. Tensile tests at RT were performed to show the influence of the microstructure on mechanical properties. Static recrystallization (SRX) was observed during annealing of as-received alloy at and above 150 deg. C. Twins play an important role during SRX and serve as nucleation sites and preferred paths for growth of grains. The strong basal texture caused by rolling was weakened by SRX. Significant differences in the stress strain curves were observed for as-received and annealed specimens.

International Nuclear Information System (INIS)

TIMETAL reg-sign 21S, which has the nominal weight percent composition 15Mo, 3Al, 3Nb, and 0.2Si, is a metastable beta titanium alloy that offers a unique combination of high strength, good elevated temperature properties, and extraordinary environmental degradation resistance. It was developed by TIMET in 1988 as a foil matrix material for titanium metal matrix composites for the NASP, but currently monolithic applications are of much more significance. Among the alloy's unique properties are a high resistance to attack by commercial aircraft hydraulic fluids (commonly referred to as Skydrol trademark, which will be the term used in this paper) at all temperatures, which has led to its use in nacelle components on the Boeing 777 and other commercial aircraft. This paper provides an overview of the physical and mechanical properties of TIMETAL reg-sign 21S.

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In this study acrylonitrile-butadiene-styrene (ABS) terpolymer was reinforced with HNO3-treated short carbon fibers (HCFs). The effects of HCF concentration on the tensile properties of the composites were examined. Increasing the HCF concentration in the ABS matrix from 10 wt% to 30 wt% resulted in improved tensile strength and tensile modulus. To obtain a strong interaction at the interface, polyamide-6 (PA6) at varying concentrations was introduced into the ABS/10 wt% HCF composite. The incorporation and increasing amount of PA6 in the composites increased tensile properties of the ABS/PA6/HCF systems due to the improved adhesion at the interface, which was confirmed by the ratio of tensile strength as an adhesion parameter. These results were also supported by scanning electron microgr...

British Library Electronic Table of Contents (United Kingdom)

The present study is focused on preparation of nano composite materials and the effect of citric acid on their different properties. The formation of nano HA and its interaction with chitosan (C), gelatin (G) polymers and citric acid (CA) materials were studied. The Fourier Transformed Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize these composite materials. The compressive strength (CS) was also measured to know the reinforcement of the prepared composites. The results show that carboxylic and amino groups play crucial role for HA formation on chitosan-gelatin polymeric matrix in the presence of citric acid (CA). The formation of nano HA part...

International Nuclear Information System (INIS)

#alpha#/#beta# sialon based composites containing silicon nitride whisker and silicon carbide platelet were fabricated by hot pressing. Effect of the reinforcing agents on the #alpha# to #beta# phase transformation of the sialon as well as on the mechanical properties was investigated. Silicon nitride whisker and silicon carbide platelet promoted the phase transformation. TEM/EDS analysis revealed that the grain containing the whisker had 'core-rim' structure; core being high purity Si_3N_4 whisker and rim being #beta#-sialon. Flexural strength of the composite decreased with the reinforcement addition which, on the other hand, improved fracture toughness of it. High temperature strength was measured at 1300 deg C to be about 130 MPa lower than that measured at RT for the whisker reinforced composite. (author).

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...

International Nuclear Information System (INIS)

Spherical nanostructured Si/C composite was prepared by spray drying technique, followed by heat treatment, in which nanosized silicon and fine graphite particles were homogeneously embedded in carbon matrix pyrolyzed by phenol formaldehyde resin. Cyclic voltammetry tests showed two pairs of redox peaks corresponding to lithiation and delithiation of Si/C composite. The Si/C composite exhibited a reversible capacity of 635 mAh g"-"1 and good cycle performance used in lithium ion batteries. To improve cycle performance of this Si/C composite further, the carbon-coated Si/C composite was synthesized by the second spray drying and heat treatment processing. The cycle performance of carbon-coated Si/C composite was improved significantly, which was attributed to the formation of stable SEI passivation layers on the outer surface of carbon shell ...

International Nuclear Information System (INIS)

Ceramic matrix composites in the TiC-Ti, Y-TZP system can be synthesized by the reaction between carbon and the TiO_2-Y_2O_3-ZrO_2 solid solution nanopowder. This method results in the more homogeneous powders than those prepared by the physical mixing of TiC and zirconia s.s. powders. Twelve TiO_2-Y_2O_3-ZrO_2 solid solution nanopowders differing in the proportions of the constituent oxides were prepared by the coprecipitation- calcination route. They were reacted with the pyrolytic carbon evenly distributed within the system. Carbon was introduced by the thermal decomposition of the phenol-formaldehyde resin dissolved in ethyl alcohol and mixed with the zirconia s.s. nanopowder. Reaction was performed in vacuum. Compacts of the composite powders sintered in vacuum give dense materials of evenly distributed TiC inclusions of sizes not surpassing 400 nm. Hardness of such materials was dependent on their chemical and phase ...

Wastenet

as a by-product during the purification of molten magnesium chloride prior to its electrolysis and during the

Wastenet

as a by-product during the purification of molten magnesium chloride prior to its electrolysis and during the

International Nuclear Information System (INIS)

The effects of catalytic metal additives on the hydrogen desorption properties of the submicrocrystalline magnesium hydride (#beta#-MgH_2) formed after hydrogenation of the Mg + 10 wt.%X (X = V, Y, Zr) mechanically (ball) milled composites were studied. The composites with catalytic metals were processed by controlled mechanical milling (CMM) in the magneto-mill Uni Ball Mill 5 under protective Ar atmosphere. X-ray diffraction of the milled powders revealed the formation of Mg nanograins (50-60 nm range) interdispersed with the nanograined metal additives within the powder particles. Scanning electron microscopy showed particle size reduction after milling. After activation and hydrogenation in a Sieverts-type apparatus under about 2 MPa pressure of hydrogen, the tetragonal #beta#-MgH_2 hydride co-exists with the small amount of retained unreacted Mg phase and the small amount of MgO in all three ...

International Nuclear Information System (INIS)

Uranium-aluminum alloys with a significant enrichment of uranium with "2"3"3U or "2"3"5U serve as nuclear fuels in research reactors. The quality assurance of this fuel requires, among other things, precise knowledge that all trace metal constituents that affect neutron economy, fuel integrity, and fuel fabrication process parameters are well within the specification limits. Trace metal characterization of "2"3"5U-Al alloy has been carried out by atomic spectrometry. The trace metal constituents of interest are grouped into common metals (silver, boron, calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, sodium, nickel, lead, silicon, tin, titanium, vanadium, tungsten, and zinc) and lanthanides (cerium, dysprosium, europium, gadolinium, holminium, lutetium, samarium, and terbium). The elements yttrium and zirconium are grouped with the latter in view of the chemical separation procedure used. The alloy samples are dissolved in 6 M ...

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This patent describes a catalyst comprising: (a) a non-zeolitic inorganic oxide matrix, and (b) an ultrastable Y-type crystalline zeolite, the ziolite having been pretreated by contacting the zeolite with a phosphorus compound selected from the group consisting of phosphoric acid, phosphorous acid, a salt of phosphoric acid, a salt of phosphorous acid, and mixtures thereof for a time sufficient to composite an effective amount of phosphorus with the zeolite.

British Library Electronic Table of Contents (United Kingdom)

In this study, the influence of Beryllium (Be) content on the fracture behaviour of Al?15%Mg2Si composite was investigated. The results showed an increase in mechanical properties with increasing of Be content. The stress?strain curves of samples showed a same category of serrations reflecting non-uniform deformation. Scanning electron microscopy was employed to examine the crack nucleation and fracture model. The results indicate that Al?15%Mg2Si composite shows different behaviours of crack initiation and fracture for samples with and without Be. Differences observed in the fracture behaviour were attributed to microstructural changes as well as morphological aspects of primary Mg2Si particles.

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Nano photonic materials are synthetically manufactured crystals at the nano scale with the target of creating a microstructure with a special electro-magnetic periodicity. Such nano photonic materials have the ability to control light propagation and thus are capable of creating photonic bandgaps in the frequency domain. We propose using nano photonic crystals as sensors to detect microdamage in composite materials. We demonstrate using a simulation model that a nano photonic sensor attached to a composite bar experiences a significant change in its bandgap profile when damage is induced in the composite bar. The model predicts the frequency response of the nano photonic sensor using the transfer matrix method. A damage metric to evaluate the change in the frequency response is developed. Successful developments of nano photonic sensors allow damage identification at scales not attainable using current ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Within the framework of the CRC 799 -TRIP-Matrix-Composites- at the TU Bergakademie Freiberg new composite materials consisting of TRIP steel and zirconium dioxide ceramics are designed in a powder route and a casting route. To manufacture faultless samples basic investigations of the feeding and infiltration behaviour within macro porous ceramics such as filters were needed. The effects of bottom pouring and top pouring were investigated as well as the effects of different preheating temperatures, contents of phosphorous in the steel and flow trough rates. Bottom pouring corrupts the feeding mainly of filters with high ppi (pores per inch). Top pouring improves the feeding, but generates inhomogeneous infiltration qualities, which can affected and enhanced by a increasing preheat...

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The carbon fibers (CF) were pre-treated in two different ways: no pre-treatment, and activation in HNO3 plus application of toluene-2,4-diisocyanate (TDI). Carbon fibers have been introduced into polyurethane (PU) composite coatings. The tribological behaviors of the polyurethane composite coating filled with CF or TDI-modified CF (TDI-CF) were studied using a ring-on-block wear tester under dry sliding, and the worn surfaces of the filled PU coatings and transfer films formed on the surface of the counterpart ring sliding against the PU coating were investigated by SEM and optical microscope (OM), respectively. Owing to the effective improvement of the interfacial adhesion between the CF and polyurethane matrix, compared with the cases of untreated CF, the employment of low content TDI-CF...

British Library Electronic Table of Contents (United Kingdom)

The influence of chemical and solvent extraction compatibilising techniques on the mechanical properties of poly-lactic acid (PLA) and MaterBi-polyester (PEM) based bio-composites are compared. First, fibres were chemically grafted with two fatty chains: stearic anhydride and octadecylisocyanate. Grafted fibres were characterised by FTIR and elemental analyses. Contact angle measurements show the hydrophobisation of the fibres in spite of very low surface grafting. Extracted and non-grafted fibres were prepared to be used as references. PEM and PLA-based composites with 30% w/w were prepared by compression moulding. Their mechanical properties were studied. It was found that chemical and solvent treatment of the fibres improved the reinforcement effect in the case of a PEM matrix and the Y...

International Nuclear Information System (INIS)

The manufacture and use of wood/plastic composite (WPC) as an example of wood matrix and wood sawdust/plastic composites (SDP) as an example of plastic matrix are reviewed. The raw material for WPC are mostly vinyl monomers, particularly methyl methacrylate and styrene. The reaction in WPC polymerization is radical polymerization. Researches on the radiation sources mostly resulted in gamma-ray. Electron beam can be applied only to thin products. The future use of WPC may be for furnitures, sporting goods, decorative parts and the like. Vital study on the reduction of manufacturing costs is required, for example, the improvement of reaction and the adoption of continuous process must be considered. The raw materials for SDP are wood sawdust, vinyl monomer (mostly methyl methacrylate) and resins. Electron beam accelerators are the most preferable radiation source because of its high efficiency and safe ...

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In order to investigate the role of amorphous SiO{sub 2} particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO{sub 2} was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of {gamma}-phase and amorphous nano-SiO{sub 2} particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO{sub 2} particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion ...

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A novel process was proposed to synthesize nano Sb-encapsulated pyrolytic polyacrylonitrile composite for anode material in lithium secondary batteries. The preparation started with the dissolution of SbCl{sub 3} and polyacrylonitrile (PAN) in dimethylformamide (DMF) solution, followed by the addition of KBH{sub 4} to reduce Sb{sup 3+} in the solution. The Sb composite was obtained by pyrolysis of the Sb/PAN mixture that precipitated out when the DMF solution was added by plentiful water. The TEM analysis showed that about 100-200 nm Sb particles were embedded by the pyrolyzed PAN, which provided a conductive matrix to relieve the morphological change of Sb during electrochemical cycling. As-prepared composite presented good cycleability for lithium storage. The proposed process paves an effective way to prepare high performance alloy based composite anode materials for high ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Ethylene-propylene-diene rubber (EPDM)/samarium borate (SmBO3)/ethylene-vinyl acetate (EVA) copolymer and EPDM/antimony-doped tin oxide (ATO)/EVA composites are aged at 150C for different intervals. Surface modification is used to improve filler to matrix interphase. The main aim is to investigate the effect of filler type and vinyl acetate (VA) content in EVA on stability of EPDM composites. It is found that acidic ATO particles can lower pH level of EPDM composites and then promote the degradation of acetic acid during aging. Moreover, when VA content exceeds 14 wt %, the instable VA content causes more acetic acids escape during aging. With the increasing of aging time, EPDM/SmBO3 control and EPDM/SmBO3/EVA composites tend to become darker while EPDM/ATO and EPDM/ATO/EVA compos...

International Nuclear Information System (INIS)

Analytical TEM and high resolution TEM were used in the microstructural characterization of hot-press sintered Si_3N_4-SiC platelets composites. The quantity of sintering additives, Er_2O_3 and AlN, was varied to produce different matrices, e. g. Si_3N_4, #beta#'+#alpha#'-Sialon and #alpha#'-Sialon. Detailed analysis of platelet-sialon matrix interfaces revealed the presence of AlN polytypoids. The polytypoids nucleate preferentially onto the (0001) plane of SiC and growth epitaxially in several ten nanometer layers contributing in this way to crystallize, partially, the matrix intergranular glass pockets contacting the platelets. Possible applications of the phenomena to microstructural control, grain boundary phase control and enhanced creep resistance are discussed. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Ni-Co/SiC nanocomposite coatings were electrodeposited in a modified watt type of Ni-Co bath containing 20nm SiC particles to be codeposited. Potentiodynamic polarization tests were conducted to study the effect of the SiC particulates on the electrodeposition of Ni and Co. Scanning electron microscopy was used to assess the morphology of the Ni-Co alloy and Ni-Co/SiC nanocomposite coatings. The distribution of the particulates in the matrix was considered by means of transmission electron microscopy. Applying nanomechanical testing instruments coupled to atomic force microscopy, mechanical properties of the alloy and composite coatings were studied and compared. The presence of 11vol.% SiC in the Ni-Co matrix increased hardness more than 60%. The average depth of scratch in the mentioned ...

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Effects of rolling conditions on warm deep drawability of cast magnesium alloy that were hot rolled after roll strip casting were investigated to ascertain the feasibility of twin-roll strip casting process of AZ31B magnesium alloy. Hot rolling and heat treatment conditions were changed to examine which conditions were appropriate for producing AZ31B wrought magnesium alloys after strip casting process. Microscopic observation of the crystals of the manufactured wrought magnesium alloys was performed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep drawing test of the cast magnesium alloy sheets after being hot rolled. (orig.)

UK PubMed Central (United Kingdom)

OBJECTIVE--To examine the effect of a reduced sodium and increased potassium and magnesium intake on blood pressure. DESIGN--Randomised double blind placebo controlled trial. SETTING--General population...Full Text Available

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The cost of transporting biogas digestate can be decreased by reducing its water content. However, the digestate emits volatile compounds during drying. This study investigated the drying behaviour and the change of digestate composition. Drying took place in a hybrid solar/waste-heat dryer that used solar energy as well as waste heat from a combined heat and power unit (CHP) and the exhaust air of a microturbine. The experiment involved the use of 60 t of liquid digestate. Climatic conditions were measured inside and outside the drying hall. Dry matter (DM) and organic dry matter (ODM) were also measured on a daily basis. In addition, the energy consumption of waste and solar heat were recorded and related to the quantity of dried feedstock. The total nitrogen, ammonium, phosphate, potassium oxide, magnesium oxide and calcium oxide in the digestate were subjected to chemical analysis before and after the drying process. Losses of nitrogen were ...

Science.gov (United States)

The extraction of magnesium by tributyl phosphate from KI solutions was investigated. With increasing KI and TBP concentrations, the extraction increased. The maximum extraction (82%) was attained at pH 4, and it did not decrease with a further pH increase. With decreasing pH, the extraction decreased because of HI extraction. The magnesium was extracted as the compound MgI/sub 2/ x 4TBP. Complexone III (at pH 3-4) does not affect the extraction of magnesium, which makes it possible to use it to mask other metals.

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Aluminum matrix composite Al356/SiCp(Vol. 15%)(Al MMC) material has been cut under various cutting conditions using Abrasive WaterJet (AWJ) machining process. The experimental cutting was carried out using three different material thicknesses of 10, 20, 30mm with a 0.33mm diameter orifice. The pump pressure, traverse rate, StandOff Distance(SOD) were taken as process parameters. After cutting the quality of the specimen in terms of kerf width, kerf taper, and surface finish were measured to characterize machinability of the material. As a result of the study, the maximum traverse rate for 30mm thick Al MMC under the pump pressure of 350 MPa reached up to 70 mm/min and the surface roughness of the material showed surface finish Ra in the range of 2.3{approx}23.4{mu}m.

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An experiment was conducted on the structure of mesoscopic calculating method for cement-based composite materials. The purpose was utilization for the simulation of mesoscale failure processes and the development of new composite materials. Mesh split based on Voronoi polygons was applied as the discrete limit analysis of the cement-based composite materials containing aggregate particles taking the arrangement of random particles into consideration, and a two-dimensional rigid-body/spring model was employed as the model. The nonhomogeneity of concrete was represented by three kinds of different spring parameters which were aggregate, mortar matrix and their interfaces. The simulation results were summarized as follows: The stress-strain curve went into a non-linear state from the 30% of the maximum stress. The generation of interfacial crack started on the side of the aggregate, but the propagation of ...

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Discontinuously reinforced aluminium-based composites containing particulate or whisker SiC reinforcements at different volume fractions, were produced via a powder-route. Isothermal creep tests have been carried out at 270, 300 and 320 C. During these tests axial and transverse strains were monitored using a non-contacting laser scanning extensometer arrangement. At the same time neutron diffraction has been used to measure the elastic phase strain evolution with composite creep deformation. It was found that after the initial loading the phase strains remained essentially constant during primary and secondary creep. This indicates that the initial matrix/reinforcement inelastic misfits remain largely unchanged, probably due to the setting up of a dynamic equilibrium between misfit generation and stress relaxation. For each system, the neutron data has been combined with Eshelby modelling to obtain a measure of the load ...

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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.)

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The nature of interaction of some boromagnesium minerals with water is studied, the main stages of interaction are established. The methods of thermo-gravimetric, X-ray phase and chemical analyses are applied to state intermediate and final phases of magnesium borate interaction with water. ''Preobrazhenskite'' - ''inderite'' paragenesis is established. The notion ''magnesium borate solubility'' is shown to be senseless.

British Library Electronic Table of Contents (United Kingdom)

The analysis of complex fluids such as crude oils, fuels, vegetable oils and mixed waste streams poses significant challenges arising primarily from the multiplicity of components, the different properties of the components (polarity, polarizability, etc.) and matrix properties. We have recently introduced an analytical strategy that simplifies many of these analyses, and provides the added potential of linking compositional information with physical property information. This aspect can be used to facilitate equation of state development for the complex fluids. In addition to chemical characterization, the approach provides the ability to calculate thermodynamic properties for such complex heterogeneous streams. The technique is based on the advanced distillation curve (ADC) metrology, wh...

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Future power plants will be more fuel efficient, environmentally benign, and economical than current power plants. A high performance power system (HIPPS), based on a coal-fired combined cycle, is currently being developed. The corrosion and temperature-strength properties of currently available metallic materials limit the maximum efficiency of this cycle. Recently, ceramic matrix composites have shown promise in overcoming the design limitations on the future power plants. In particular, the high-temperature, and corrosion and erosion resistant properties of continuous fiber ceramic composites (CFCCs) will allow engineers to design high-temperature heat exchangers, cyclone vortex finder tubes, and other components. Research being performed to evaluate candidate materials for use in future power plants is discussed.

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Super light and high performance Mg{sub 2}Si/Mg composites, which had excellent mechanical properties, were developed via the combination of solid-state synthesis and hot extrusion process. In this study, cold compacting (CP) and repeated plastic working (RPW) were firstly carried out for the mixture of Mg-Si powders, and the refinement of both Mg grains and dispersoids. Each specimen was evaluated by observation of microstructure and tensile test. As a result, it was understood that Mg{sub 2}Si dispersoids were refined and dispersed into Mg matrix, and were flowed along extrusion direction. And their mechanical properties were higher than the conventional die casting alloys. Also the effect of RPW as the improvement of properties and the decrease of synthesis temperature were confirmed. (orig.)

British Library Electronic Table of Contents (United Kingdom)

A electrogenerated chemiluminescence (ECL) sensor for itopride was developed based on tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)32+)-doped silica (RuDS) nanoparticles/biopolymer chitosan composites membrane modified glassy carbon electrode (GCE). The RuDS nanoparticles (52+-5nm) were prepared by a modified Stber synthesis method and were characterized by electrochemical, fluorometric and transmission electron microscopy technology. The Ru(bpy)32+ encapsulation interior of the silica nanoparticle maintains its electrochemical activities and also reduces Ru(bpy)32+ leaching from the silica matrix when immersed in water due to the electrostatic interaction. The ECL analytical performances of this ECL sensor for itopride based on its enhancement ECL emission of Ru(bpy)32+ were investigated in d...

British Library Electronic Table of Contents (United Kingdom)

As part of the United States Department of Agricultures (USDA) National Food and Nutrient Analysis Program (NFNAP), food composition data for vitamin D in the USDA National Nutrient Database for Standard Reference are being updated and expanded, focusing on high priority foods and validated analytical methodology. A lack of certified reference materials and analytical methods validated for these key foods required the development of five matrix-specific control composite materials (CC) (canned salmon and vitamin D3 fortified cereal, orange juice, milk, and cheese). Each of six experienced laboratories (research and commercial) analyzed vitamin D3 in five subsamples of each CC in five separate analytical batches, with one subsample of each material in each run. Research laboratories perform...

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On the basis of observations of the JTEC team, it appears that Japanese universities and research institutes are leading long-term R&D thrusts for development of new materials casting technologies. Significant efforts include amorphous metals, intermetallics, application of MHD in continuous casting of steel, and energy efficient furnace technology. Industrial R&D seems focused more on process improvements than on new product technologies, but significant efforts in new cast materials included cast metal matrix composites, materials substitutions for thinner wall products, and advanced ceramic products for foundry industry applications.

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A considerable fraction of radioactivity entering the environment from different nuclear events is associated with particles. The impact of these events can only be fully assessed where there is some knowledge about the mobility of particle bound radionuclides entering the environment. The behavior of particulate radionuclides is dependent on several factors, including the physical, chemical and redox state of the environment, the characteristics of the particles (e.g., the chemical composition, crystallinity and particle size) and on the oxidative state of radionuclides contained in the particles. Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized using non-destructive analytical and microanalytical methods. By determining the activity of {sup 239,240}Pu and {sup 241}Am isotopes from their gamma peaks structural information related to Pu matrix was obtained, and the source term was ...

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This paper deals with an experimental study of ultra-precision diamond cutting of magnesium alloy (AZ31). In order to investigate the machinability such as the cutting force and the surface integrity and understand the problems in a micro cutting, the experiments on the diamond cutting of magnesium alloy and pure aluminum with an ultra-precision turning machine has been carried out. The machinability of magnesium alloy was compared with that of pure aluminum and discussed. Consequently, both the thrust force component and the surface roughness obtained by cutting of magnesium alloy became larger than that of pure aluminum. It was also found that the inclusions or the defects in the work material caused to generate the scratches on the finished surface and influenced the integrity of mirror surface. (orig.)

CERN Document Server

Statistical Inference, Econometric Analysis and Matrix Algebra

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We examined, using thermo analytical methods, the effects of 2000 deg. C heat-treated graphite powders and heating rate of cure after impregnation on the thermal stability and carbon yield of furfuryl alcohol, which is frequently used not only as an impregnation but also as a matrix precursor for carbon fiber-reinforced carbon composites. It was founded that the addition of 30 wt%. graphite powders of furfuryl alcohol and the heating rate 35 deg. C/min showed the highest thermal stability of furfuryl alcohol/graphite powder mixture. The carbon yield above 1000 deg. C was enhanced more than 10% in comparison with the absence of graphite powders. It would be expected that this result can contribute to some extent to reduce the repeating number of processing cycle (carbonization {yields} impregnation {yields} cure {yields} re-carbonization) required to density a carbonaceous composite. (author). 9 refs., 8 figs.

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In case of airplane engine, technical development like increase of temperature at the turbine entrance or high speed rotation with a purpose of thrust up, and reduction of structural part single substance mass or reduction of number of parts in order to achieve lightness and so forth, has been promoted in order to improve the performance that is evaluated by thrust weight ratio (thrust/weight). Accordingly, research and development of high heat resistance, high strength, lightness and so forth of each material of the parts are in demand. As a representative material corresponding to such demand, L10 type {nu}-TiAl intermetallic compound which is light and has improved high temperature strength properties is paid attention and its development is promotes. The authors were successful for the first time in the world to manufacture composite material with CVD type SiC fiber that was difficult so far by using TiAl-Cr alloy having super plasticity at comparatively low ...

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The advent of light metal alloys and advanced materials (polymer, composites, etc.) have brought the possibility of achieving important energy reductions into the full life cycle of these materials, especially in transportation applications. 1 These materials have gained acceptance in the aerospace industry but use of light metal alloys needs to gain wider acceptance in other commercial transportation areas. Among the main reasons for the relatively low use of these materials are the lack of manufacturability, insufficient mechanical properties, and increased material costs due to processing inefficiencies. Considering the enormous potential energy savings associated with the use of light metal alloys and advanced materials in transportation, there is a need to identify R&D opportunities in the fields of materials fabrication and forming aimed at developing materials with high specific mechanical properties combined with energy efficient processes and good ...

Science.gov (United States)

Polymer matrix composites are presently used in many fields due to their excellent mechanical properties such as high specific strength and stiffness. However, not much is known of these composites' response to impact loading, which usually occurs at strain rates much higher than the strain rates used to measure the quasi-static mechanical properties of materials. The use of static properties in the study of structures that undergo dynamic loading can produce excessive design weight or cause unexplained and untimely failure. The studies included in this dissertation provide the results of Split Hopkinson Pressure Bar experiments to determine the ultimate compressive strength and strain of composites at high strain rates. Most researchers are using specimens with different dimensions and geometry. For this reason, it is difficult to compare results of tests done by different people. Herein, the Split ...

International Nuclear Information System (INIS)

Ti-15Mo-2.7Nb-3Al-0.2Si (Timetal-21S), a metastable #beta#-titanium alloy, is a candidate material for titanium matrix composite structures in hydrogen-fueled hypersonic planes because of its excellent formability and adequate mechanical properties in the 500--800 C temperature range. The alloy is strengthened through the precipitation of fine #alpha# particles in the #beta# matrix. The mechanical properties and microstructures are controlled by a solutionizing/aging heat treatment. A major concern in using titanium alloys in hydrogen service is the embrittlement caused by the precipitation of hydrides. It is believed that the large solubility of hydrogen in the #beta#-phase would preclude the precipitation of hydrides in Beta titanium alloys, especially at low hydrogen pressures. However, depending on the hydrogen content, a shift in the ductile/brittle transition temperatures to levels much higher than room temperature ...

International Nuclear Information System (INIS)

The development of light-weight vehicle is in great demand for enhancement of fuel efficiency and dynamic performance. The vehicle weight can be reduced effectively by using lightweight materials such as magnesium alloys. However, the use of magnesium alloys in sheet forming processes is still limited because of their low formability at room temperature and the lack of understanding of the forming process of magnesium alloys at elevated temperatures. In this study, uniaxial tensile tests of the magnesium alloy AZ31B-O at various temperatures were performed to evaluate the mechanical properties of this alloy relevant for forming of magnesium sheets. To construct a FLD (forming limit diagram), a forming limit test were conducted at temperature of 100 and 200 deg. C. For the evaluation of the effects of the punch temperature on the formability of a rectangular cup drawing with AZ31B-O, ...

Energy Technology Data Exchange (ETDEWEB)

Magnesium is known to have poor formability at room temperature, mainly attributed to its hexagonal lattice structure. This paper presents the findings generated from development of warm forming to produce thin-walled magnesium components. Finite element analysis was conducted to evaluate the formability of the material and the simulated results were compared to the tensile results and product formability. Tensile tests were used to verify the formability of the sheet metal at difference temperatures. The process parameters considered in the feasibility study were forming temperature, in the range of 28 C to 300 C and magnesium sheet (AZ31B-H24) thickness, in the range of 0.4 mm to 1 mm. Magnesium hand phone covers of a thickness down to 0.4 mm have been successfully produced. The feasible forming temperature was found to be between 200 C and 250 C. Metallographic examination shows evident of ...

Energy Technology Data Exchange (ETDEWEB)

A chromium-free conversion coating for magnesium alloys were described. The conversion coating could be obtained when AZ31D magnesium alloy was immersed in a solution containing a manganese salt, phosphate and an inhibitor. Corrosion resistance of the chemical conversion coating was evaluated by anodizing polarization curve and salt immersion. XRD analysis showed that the conversion coating was mainly composed of Mn{sub 3}(PO{sub 4}){sub 2}. The morphology of the coating is observed by using SEM. The effect of electrolyte pH and concentration of inhibitor on coating growth are investigated. (orig.)

International Nuclear Information System (INIS)

In laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), the properties of laser-generated aerosols, such as size and composition, are crucial for matrix-independent quantification. In this study, the aerosol particle morphology and elemental composition generated by two state-of-the-art laser systems (ArF excimer nanosecond-UV laser and Ti:sapphire femtosecond-IR laser) were investigated by electron microscopic techniques. Electrostatic sampling of the aerosols directly onto transmission electron microscopy (TEM) grids allowed us to study the morphology and elemental composition of the aerosols using TEM and TEM-EDX (energy dispersive X-ray spectroscopy) analyses, respectively. The results of the electron microscopic studies were finally compared to the LA-ICPMS signals of the main matrix components. The investigations were carried out for non-conducting materials ...

Science.gov (United States)

... alloys--Lanthanum-- Magnesium--Magnasium &11oy8--Hagn*31Uft compounds--Manxganese--Manganes. alloys-- Mercury ...

International Nuclear Information System (INIS)

Magnesium alloys have been increasingly used in automotive and electronic industries because of their excellent strength to weight ratio and EMI shielding properties. However, magnesium alloys have low formability at room temperature due to their unique mechanical behavior (twinning and untwining), prompting for forming at an elevated temperature. In this study, a temperature dependent constitutive model for magnesium alloy (AZ31B) sheet is developed. A hardening law based on non linear kinematic hardening model is used to consider Bauschinger effect properly. Material parameters are determined from a series of uni-axial cyclic experiments (T-C-T or C-T-C) with the temperature ranging 150-250 deg. C. The influence of temperature on the constitutive equation is introduced by the material parameters assumed to be functions of temperature. Fitting process of the assumed model to measured data is presented and the results are ...

International Nuclear Information System (INIS)

One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At the same time, it identifies both the mechanism of pore formation and a remedy for this problem. The experimental results indicate that lacking of shielding gas for laser beam is the dominant cause of macroporosity formation during the hybrid of laser-TIG welding of magnesium Alloys AZ31B plate, and hydrogen is not main cause to form large pores. A favorable weld without porosity can be obtained by appending lateral shielding gas for laser beam.

Energy Technology Data Exchange (ETDEWEB)

In this paper, for an acceleration of utilization of magnesium alloy which is being interested in recent years, friction welding of AZ31 magnesium alloy was carried out, and the joint performance was discussed in relation to the deformation heat input in the upset stage and upset loss as a evaluation factor. Where, the deformation heat input in the upset stage is mechanical work represented by the product of upset speed and axial pressure. As a result, it was made clear that the friction welding of AZ31 magnesium alloy was easy in the atmosphere, and good welded joints without a non- adhesion area at the weld interface could de obtained. Moreover, the evaluation factors discussed were possible to evaluate to joint performance. (orig.)

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.)

Energy Technology Data Exchange (ETDEWEB)

A new technique was proposed in order to improve poor corrosion resistance in magnesium. That is, magnesium hydroxide film was formed on the surface of 3 N-Mg by artificial corrosion in 1% MgCl{sub 2} solution for 3.6 ks, which followed by oxidation at 673 K for 3.6 ks in air. Corrosion resistance was evaluated by salt immersion tests in 1% NaCl solution under in situ laser microscopic observations. Bubble evolution, which occurred immediately at the beginning of the immersion test in the case of non-treated specimen, was suppressed by the process. And also, formation of filiform corrosion was suppressed for about 3.6 ks, which occurred at 180 s in the non-treated specimen. (orig.)

International Nuclear Information System (INIS)

This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB milling will create major ...

International Nuclear Information System (INIS)

This study demonstrates amplified spontaneous emission (ASE) of the ultraviolet (UV) electroluminescence (EL) from ZnO at #lambda##approx#380 nm in the n-ZnO/ZnO nanodots-SiO_2 composite/p- Al_0_._1_2Ga_0_._8_8N heterojunction light-emitting diode. A SiO_2 layer embedded with ZnO nanodots was prepared on the p-type Al_0_._1_2Ga_0_._8_8N using spin-on coating of SiO_2 nanoparticles followed by atomic layer deposition (ALD) of ZnO. An n-type Al-doped ZnO layer was deposited upon the ZnO nanodots-SiO_2 composite layer also by the ALD technique. High-resolution transmission electron microscopy (HRTEM) reveals that the ZnO nanodots embedded in the SiO_2 matrix have diameters of 3-8 nm and the wurtzite crystal structure, which allows the transport of carriers through the thick ZnO nanodots-SiO_2 composite layer. The high quality of the n-ZnO layer was manifested by the well crystallized lattice image in the ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes an innovative use of post-consumer waste HDPE plastic in concrete as a soft filler. A reference concrete was proportioned to have the 28-day compressive strength of 5000 psi (35 MPa). A high-density plastic was shredded into small particles for use in the concrete. These particles were subjected to three chemical treatments (water, bleach, bleach + NaOH) to improve their bonding with the cementitious matrix. The plastic particles were added to the concrete in the range of 0--5% of total mixture by weight. Compressive strengths were measured for each test mixture. The results showed that chemical treatment has a significant effect on performance of the plastic filler in concrete. Of the three treatments used on the plastic, the best performance was observed with the alkaline bleach treatment (bleach + NaOH) with respect to compressive strength of concrete.

British Library Electronic Table of Contents (United Kingdom)

Highly dispersed silver nanoparticles embedded in mesoporous thin films (MTFs) have been synthesized by modification of the interior surface of mesoporous silica with ethylenediamine moieties, which provided the coordination sites for the Ag ions, and subsequent reduction under hydrogen atmosphere. TEM observations show the mesoporous parent films have effectively controlled the growth of the synthesized silver nanoparticles. The composite films had an ultrafast nonlinear response time, as fast as 200 fs, and a third-order nonlinear optical susceptibility of 0.94??10?10 esu, which was enhanced by the local field enhancement effect that was present when the silver nanoparticles were embedded in the surrounding dielectric matrix. The origin of the ultrafast nonlinear response and the enhanc...

British Library Electronic Table of Contents (United Kingdom)

In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40nm was made of TiO"2 through the hydrolysis of (NH"4)"2TiF"6. Second, silver nanoparticles with the diameter of about 3nm were added into the TiO"2 layer through thermal decomposition of AgNO"3 at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to...

Energy Technology Data Exchange (ETDEWEB)

Titanium oxides were grown anodically to selected final potentials on grade II polycrystalline titanium under different anodization rates. XPS and RBS results show that the oxide consists of primarily TiO2 with a non-stoichiometric oxide/metal interface, with the slower growth rate associated with a thicker layer at the interface. Characterization using TEM reveals that the structure of the oxide evolves from a primarily amorphous phase to islands of crystallites in an amorphous matrix, to an entirely crystalline phase by increasing the polarization potential. Slower growth rates tend to remain crystalline at higher potentials. The mechanical strength of oxide films extracted from load-depth data by nanoindentation varies dramatically for oxide films grown by different rates at 9.4 V, and to a lesser extent at lower potentials. The variation of film strength is associated with both compositional and structural characteristics.

International Nuclear Information System (INIS)

Nanometer Ce-W composite materials have been prepared by the method of freeze-drying. Microstructure and surface properties of materials were investigated by SEM and 'in situ' AES and emission characteristics have been determined. It is found that the nanometer materials have relatively small crystal particles with average dimensions in the order of 50 nm. Due to the results of matrix analysis, the cerium in the materials is uniformly distributed on submicron scale, which proves that the diffusion ability of cerium has been increased. Under high temperature, the active layer on the surface thickens simultaneously with the increase of cerium and oxygen. As a result, nanometer Ce-W materials exhibit excellent emission characteristics compared with those of micron-sized Ce-W materials.

British Library Electronic Table of Contents (United Kingdom)

The formation of nanoparticles during the radiation-induced chemical reduction of silver ions, copper ions, and nickel ions in films based on poly(acrylic acid)-poly(ethylenimine) complexes are studied via electron microscopy. This approach allows preparation of composites containing nanoparticles that are randomly distributed in the polymer matrix and materials with a regular spatial distribution of nanoparticles across the film thickness and in subsurface layers. The structure of metal-polymer hybrid materials is dependent on the irradiation conditions, the type of reduced metal ions, and their initial content in polymer matrices. The ratio between the rate of nucleation and the rate of growth of nanoparticles in the matrices of interpolyelectrolyte complexes depends on the intensity of ...

Energy Technology Data Exchange (ETDEWEB)

An easy and simple method for gamma assay of large multi-gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following two simple well known facts: large and small samples of the same homogenous material have identical specific activities; the self-attenuation of gamma line decreases as its energy increases. The method was successfully applied to naturally occurring radioactive material (NORM) large samples. This method does not require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed.

International Nuclear Information System (INIS)

An easy and simple method for gamma assay of large multi gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following tow simple well known facts: Large and small samples of the same homogenous material have identical activities; the self attenuation of gamma line decreases as its energy increases. The method was successfully applied to NORM (Naturally Occurring Radioactive Material) large samples. This method doesn't require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed. (author)

British Library Electronic Table of Contents (United Kingdom)

High purity W and W-0.9La2O3 (wt.%) nanopowders were produced by a wet chemical route. The precursor was prepared by the reaction of ammonium paratungstate (APT) with lanthanum salt in aqueous solutions. High resolution electron microscopy investigations revealed that the tungstate particles were coated with oxide precipitates. The precursor powder was reduced to tungsten metal with dispersed lanthanum oxide. Powders were consolidated by spark plasma sintering (SPS) at 1300 and 1400degreeC to suppress grain growth during sintering. The final grain size relates to the SPS conditions, i.e. temperature and heating rate, regardless of the starting powder particle size. Scanning electron microscopy revealed that oxide phases were mainly accumulated at grain boundaries while the tungsten matrix ...

DEFF Research Database (Denmark)

Udgivelsesdato: July

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 ...

International Nuclear Information System (INIS)

Control of thermal expansion is often necessary in the design and selection of electronic packages. In some instances, it is desirable to have a coefficient of thermal expansion intermediate between values readily attainable with single or two phase materials. The addition of a third phase in the form of fillers, whiskers, or fibers can be used to attain intermediate expansions. To help design the thermal expansion of multiphase materials for specific applications, a closed form model has been developed that accurately predicts the effective elastic properties of isotropic filled materials and transversely isotropic lamina. Properties of filled matrix materials are used as inputs to the lamina model to obtain the composite elastic properties as a function of the volume fraction of each phase. Hybrid composites with two or more fiber types are easily handled with this model. This paper reports that results for glass, quartz, ...

Energy Technology Data Exchange (ETDEWEB)

In order to investigate the extrusion characteristics of magnesium alloy (AZ31), a computer simulation was attempted. Tensile properties of as-cast billet with different strain rates were incorporated into the simulation. The results showed a great change in distribution of stress and strain at near die region by the ram travel. It was found that the average grain size at longitudinal edge of the extruded sheet was smaller than that at center region, which might be attributed to recrystallization caused by severe plastic deformation. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Laser-Induced Breakdown Spectroscopy was selected by NASA as part of the ChemCam instrument package for the Mars Science Laboratory rover to be launched in 2009. ChemCam's Laser-Induced Breakdown Spectroscopy instrument will ablate surface coatings from materials and measure the elemental composition of underlying rocks and soils at distances from 1 up to 10 m. The purpose of our studies is to develop an analytical methodology enabling identification and quantitative analysis of these geological materials in the context of the ChemCam's Laser-Induced Breakdown Spectroscopy instrument performance. The study presented here focuses on several terrestrial rock samples which were analyzed by Laser-Induced Breakdown Spectroscopy at an intermediate stand-off distance (3 m) and in an atmosphere similar to the Martian one (9 mbar CO{sub 2}). The experimental results highlight the matrix effects and the measurement inaccuracies due to ...

International Nuclear Information System (INIS)

The oxygen vacancies distribution in the rigid lattice and the thermally activated motion of oxygen atoms are studied in La1-xSrxGa1-xMgxO3-x (x=0.00; 0.05; 0.10; 0.15 and 0.20) compounds. For that 71Ga, 25Mg and 17O NMR was performed from 100 K up to 670 K, and ion conductivity measurements were carried out up to 1273 K. The comparison of the electric field gradients at the Ga- and Mg-sites evidences that oxygen vacancies appear exclusively near gallium cations as a species trapped below room temperature in local clusters, GaO5/2-#square#-GaO5/2. These clusters decay at higher temperature into mobile constituents of the structural octahedra Ga(O5/6#square#1/6)6/2. At the same time, the nearest octahedral oxygen environment of magnesium cations persists at different doping levels. The case of two adjacent vacant anion sites is found highly unlikely within the studied doping range. The thermally activated oxygen motion starts to develop above room temperature as is ...

Energy Technology Data Exchange (ETDEWEB)

The first Russian reprocessing facility, known as RT-1 (located at PA-Mayak in Ural region) was started on the radiochemical plant base in 1977. Nowadays RT-1 is the sole operating reprocessing plant in Russia. The main features of RT-1 is its broad spectrum of reprocessing spent nuclear fuels (SNF). The following spent fuel types are reprocessed: -) SNF from PWR reactors (WWER-440) and FB reactor (BN-600); -) SNF of transport ship reactors; -) production reactors SNF; -) research reactor spent nuclear fuel. The world-known technological processes are used at RT-1, but there are the following distinctive features. First, the universality of the three technological lines which allows not only the reprocessing of various SNF kinds, but also to implement the combined reprocessing of some types of them. Secondly, extraction of neptunium during SNF reprocessing which is used to implement its separate storage and for radioisotope production. Thirdly, target enrichment of recycled uranium is ...

Energy Technology Data Exchange (ETDEWEB)

Lithium-ion batteries are becoming more and more important not only for portable electronic devices, but also in prevision of high power electric vehicles. In such an optic, deep studies regarding all the components of a secondary battery are in development. In this study, high voltage cathode materials have been selected. Crystals with spinel structure have a 3D vacancy pathway suitable for Li-ions transport. The material under study was LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} doped with magnesium replacing the nickel. Various samples were synthesized via three different routes: a solid-state method, a modified sol-gel method and a xerogel method. The structure and morphology of the powders were analyzed with HRTEM and XRD. Electrochemical tests were also performed. A wide range of particle sizes (from micro to nanosize) was the result of the different synthesis routes. Unfortunately pure materials were not always obtained. The electrochemical tests showed improvement of ...

Energy Technology Data Exchange (ETDEWEB)

Various methods for storing hydrogen have been examined in an effort to find ways to store hydrogen in increasingly smaller volumes with decreasing weight of the whole hydrogen storage system. Metal hydrides, in which hydrogen is chemically bound to a metal atom, are considered to be very promising candidates for hydrogen storage because they have high gravimetric and volumetric storage capacities. This study investigated the effect of different magnesium (Mg) and aluminium (Al) ratios on the absorption and desorption properties of thin films. Neutron reflectometry (NR) was used in this study to better understand the absorption and desorption properties of commercially promising hydrogen storage materials. The large negative scattering length of hydrogen atoms changes the reflectivity curve substantially, so that NR can determine the total amount of stored hydrogen as well as the hydrogen distribution along the film normal, with nanometer resolution. In order to ...

Energy Technology Data Exchange (ETDEWEB)

PVD-chromium-nitride coated samples of substrates of the magnesium alloy AZ91hp and the roller and ball bearing steel 100Cr6 were investigated regarding structure, mechanical characteristics, adhesion and internal stresses. For the coatings the parameters layer thickness and substrate BIAS voltage were varied. Both substrate materials were coated in one lad. Results of the X-ray analysis of the internal stresses show significant differences between the coated magnesium and the coated steel substrates. In the case of the variation of the substrate BIAS voltage, for the coated steel a dependency of the internal stresses to coating parameters could be obtained. For the coated magnesium no dependency was recognizable. The coating structure was examined with scanning electron microscopy. Element depth profiles of the coated samples were performed with SIMS. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The friction and wear properties of glass fiber reinforced composites of nylons (nylon 6, nylon 66 and nylon 46) with different crystallinities due to their molecular structures were investigated by sliding them with alumina ceramics and using a pin-on-disk friction machine. The friction coefficients of the glass fiber reinforced nylons in oil were lower and more stable than those in air from the initial stage of friction. The transfer of nylon matrix to adhere onto the alumina surface in air was so much greater than in oil that the alumina surface could not be recognized. Consequently, a different between the friction and wear properties in air and in oil was resulted. Reinforcement of nylons with glass fiber remarkably improved their friction properties in oil by its lubricating action, while the wears were rather high contrary to what was expected. This tendency was conspicuous for nylon 46 with high crystallinity. Breakage and extracting of ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this work was to develop a method to distinguish between different ion formation processes and to determine the influence of these processes on the total number of detected monatomic ions of a certain element. A vector/matrix-formalism was developed, which describes the physical processes of sputtering, ion formation, mass separation and detection in laser-SNMS. In the framework of the method developed, based on this theoretic formalism, changes in the secondary flux contribution of the respective element were observed by comparing the detected monatomic ion yield obtained in specifically aligned (SIMS and) laser-SNMS experiments. The yields resulting from these experiments were used to calculate characteristic numbers to compare the flux composition from different surfaces. The potential of the method was demonstrated for the elements boron, iron and gadolinium by investigating the changes in the flux ...

International Nuclear Information System (INIS)

An experimental study on superplastic forming behaviors and microstructure characters of commercial magnesium alloy sheet AZ31B is presented in this paper. The main experimental results show that the commercial magnesium alloy AZ31B sheet has superplastic capability. For the received sheet without any pre-processing, the maximum elongation is 295%. The dynamic recrystallization and grain refinement can be found, In the case of temperature =# 350 deg. C. The superplastic behaviors can be improved by controlling the dynamic recrystallization and grain refinement. Some experimental results of free superplastic bulging are presented in this paper. The results show that influence of temperature on forming capability is much less than the influences of temperature on elongation. In addition, the maximum principle strain.

Energy Technology Data Exchange (ETDEWEB)

Materials and processing designs for advanced magnesium alloys with fine microstructures and superior properties were established by the combination of the repeated plastic working and the Mg{sub 2}Si synthesis in solid-state. The grain size was less than 1 {mu}m via RPW process due to its severe plastic working on raw powder. The hot extruded magnesium alloys produced in industries showed high ultimate tensile strength, e.g. 420{proportional_to}450 MPa, when employing Mg-Zn-Al-Ca-RE (Rare Earth) alloy coarse powder, having 0.5{proportional_to}2 mm diameter, as input materials. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Following the breakthrough for cast magnesium products, interest is now spreading to wrought applications - triggering a variety of technological questions. A major bottleneck in the manufacture of magnesium sections (profiles) by conventional hot extrusion is the low productivity, with extrusion speeds typically five to ten times lower than for comparable aluminium sections. This paper focuses on the use of hydrostatic extrusion as a means to overcome this problem. On the basis of an analytical model, it is clarified why and how process limits are affected by the process mechanics. Experimental work on the hydrostatic extrusion of the alloys M1A, ZM21 and AZ31 confirms that extrusion speed is indeed multiplied, whereas the resulting mechanical properties are similar to or better than those for conventional extrusions. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Substitution of various rare earths R within the class of R2PdSi3 single crystals with hexagonal AlB2-type crystallographic structure reveals the systematic dependence of anisotropic magnetic properties governed by the interplay of crystal-electric field effects and magnetic two-ion interactions. Here we compare the floating zone (FZ) crystal growth with radiation heating of compounds with R = Tb, Tm, Pr, and Gd. The congruent melting behavior enabled moderate growth velocities of 3 to 5 mmh-1. The preferred growth directions are close to the basal plane of the hexagonal unit cell. The composition of the crystals, except of Tb2PdSi3, is slightly Pd-depleted with respect to the nominal composition 16.7 at.% Pd. Thin precipitates of RSi secondary phases were detected in the crystal matrix. Their phase fraction can be diminished by growth from Pd-rich melt compositions and annealing treatments. The ...

International Nuclear Information System (INIS)

This paper discusses the structural and compositional changes at the nanometer scale associated with the nucleation and growth of #alpha# precipitates in the #beta# titanium alloy Ti-5553 (Ti-5Al-5Mo-5 V-3Cr-0.5Fe) with #omega# precipitates acting as heterogeneous nucleation sites. The microstructural evolution in this alloy, during #beta#-solutionizing, quenching and aging type heat-treatments, has been investigated by combining results from scanning electron microscopy, orientation imaging microscopy, transmission electron microscopy, high-resolution TEM and three-dimensional atom probe (3DAP) tomography. Athermal #omega# precipitates form in this alloy on quenching from above the #beta# transus temperature. On isothermal annealing at low temperatures, these #omega# precipitates coarsen to form chemically ordered #omega# precipitates, accompanied by the nucleation of the stable #alpha# phase. Annealing at higher temperatures leads to dissolution of #omega# and ...

International Nuclear Information System (INIS)

Luminescence and reflection spectra as well as luminescence kinetics of the 1 mol% Sm3+-doped crystalline lanthanum magnesium meta borate (LaMgB5O10) and gadolinium magnesium meta borate (GdMgB5O10) were analyzed. Materials were synthesized by conventional solid state route and showed bright orange-red emission under UV excitation. Emission spectra contain sharp and well resolved Sm3+4G5/2#->#6HJ transitions indicating a strong crystal-field effect. In case of gadolinium compound energy transfer between Gd3+ and Sm3+ was detected. The luminescent kinetics of the Sm3+ in analyzed powders is characterized by single exponential decay and experimental values vary in the range 2.2-2.4 ms. - Research highlights: ? Phosphorescence of samarium-doped lanthanide magnesium meta borates. ? Bright and well resolved orange-red emission of Sm3+ under UV excitation. ? Energy transfer from Gd3+ to Sm3+ in gadolinium ...

UK PubMed Central (United Kingdom)

A novel therapeutic compound was found to induce bladder tumors in male rats. Given the location of the tumors and the increased amounts of calcium- and magnesium-containing solids found in the urine...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The possibility of improving the cold formability of wrought magnesium alloys is considered in light of their good hot forming characteristics. Magnesium alloy AZ31B sheet is selected as a model system. Parameters affecting formability, such as strain hardening rate, strain rate sensitivity, and the degree of anisotropy are examined systematically by conducting tensile tests over a range of temperatures (room temperature to 250 C) and strain rates (1 x 10{sup -5} to 0.1 s{sup -1}). The plastic anisotropy and deformation texture evolution are examined in samples aligned with the sheet rolling and transverse directions. Polycrystal plasticity simulations using a viscoplastic self-consistent (VPSC) formulation are used to model the observed anisotropy and texture evolution. The adjustable parameters in the model are the relative critical resolved shear stresses of the dislocation mechanisms known to operate within magnesium. ...

International Nuclear Information System (INIS)

Chemical and phase homogeneity of titanium-niobium sponge, produced by a combined magnesium-thermic reduction of niobium pentachloride and titanium tetrachloride mixtures, is investigated. It is ascertained that a sponge consists of spherical shape particles and has a large number of pores. Particle sizes are reduced with niobium being substituted for titanium from 50-500 #mu#m for titanium sponge to 1-40 #mu#m for niobium one, which testifies to the bormation in a titanium-niobium sponge of an alloy and not a mechanical mixture. A number of solid solutions is detected by X-ray phase analysis. Lattice parameters are determined.

British Library Electronic Table of Contents (United Kingdom)

A new coumarin-based sensor molecule (L1) has been synthesized and this was found to bind calcium and magnesium ions more effectively as compared to other alkali/alkaline earth/lanthanide and certain transition metal ions. A significant enhancement in fluorescence intensity was observed on binding to Ca2+ and Mg2+ ions; while a minor quenching was observed for weakly bound Hg2+, Ni2+, Fe3+, and Co2+ ions. PET process, coupled with the ICT process, is proposed to explain the observed spectral response.

Energy Technology Data Exchange (ETDEWEB)

Optimum conditions for microstructural control in industrial hot working of cast and homogenized AZ31 magnesium alloys are evaluated by using a processing map. The recommended window for bulk metal working of this alloy is the domain in the temperature range 300-450 C and strain rate range 1-10 s{sup -1}, and the optimum processing parameters are 400 C and 10 s{sup -1}, where grain-boundary self diffusion is the rate-controlling mechanism. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Science.gov (United States)

... N ? M is not forgotten during calculations. The parameter covariance matrix, often referred to as the model covariance matrix, ... ...

Science.gov (United States)

of the determinant of the parameter covariance matrix for each ... parameter covariance matrix, as obtained from the Markov chains. The basic set ...

Energy Technology Data Exchange (ETDEWEB)

A review of the various solidification agents and techniques that are currently available or potentially applicable for the solidification of low-level radioactive wastes is presented. An overview of the types and quantities of low-level wastes produced is presented. Descriptions of waste form matrix materials, the wastes types for which they have been or may be applied and available information concerning relevant waste form properties and characteristics follow. Also included are descriptions of the processing techniques themselves with an emphasis on those operating parameters which impact upon waste form properties. The solidification agents considered in this survey include: hydraulic cements, thermoplastic materials, thermosetting polymers, glasses, synthetic minerals and composite materials. This survey is part of a program supported by the United States Department of Energy's Low-Level Waste Management Program (LLWMP). This ...

Energy Technology Data Exchange (ETDEWEB)

Silver silica nanocomposites were obtained by the sol-gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO{sub 3}) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO{sub 3} concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied. For decreasing nanoparticle size, a redshift and ...

International Nuclear Information System (INIS)

The optical properties of divalent europium activated Ca-#alpha#-SiAlON were investigated and the excitation and emission processes were discussed. The emission wavelength is influenced by the activator concentration of Eu more than the codopant concentration of Ca, in case of the same matrix composition of #alpha#-SiAlON. The red-shift of emission increases when the concentration of Eu increases. In addition, it was revealed that the red-shift of emission would be caused by the construction of the package of optical device. The correlated color temperature becomes low by the red-shift for the white light-emitting diode (LED) lamp using Ca-#alpha#-SiAlON:Eu phosphor when the phosphor powder concentration increases in the transparent resin which coats the primary light source of a blue LED die. The additional red-shift can be observed when the excessive amount of phosphor coating is intentionally poured to the white LED lamps. These red-shifts ...

International Nuclear Information System (INIS)

Three types of titanium hydrides have been reported: #delta#, #epsilon# and #gamma# hydrides. The #delta# hydride forms in the composition range from TiH/sub 1.5/ to TiH/sub 1.99/ and has a CaF/sub 2/ structure with metal atoms on an fcc lattice and hydrogen atoms randomly occupying tetrahedral interstitial sites. At higher hydrogen concentrations, TiH/sub 2/, the fct (c/a # #epsilon# transformation is apparently diffusionless, similar to that operating in the cubic/tetragonal transformation in zirconium hydride. The metastable fct #gamma# hydride having a c/a value of 1.09 or 1.12 forms from solid solutions of hydrogen in the hcp #alpha# matrix. While the titanium hydride precipitation in #alpha#-Ti and its alloys has attracted extensive investigation, hydride formation in bcc #beta#-Ti alloys has rarely been studied because they have not been thought to be liable to hydride formation. This paper shows conclusive evidence for the fcc #delta# ...

Energy Technology Data Exchange (ETDEWEB)

The major objective of this work is to seek for new solutions that can lead to significant lifetime improvement of submerse lines which experience severe wear processes on the polymeric layer coating used for protection of the touch down point (TDP) region. Four different materials were selected as possible candidates for the coating layer of this critical region. They are commercially available and posses well known processing technologies. The materials are two polymers: nylon 66 and polyacetal; and two composites: nylon 66 reinforced with 13 or 33% glass fiber. Stress-strain behavior was evaluated using two deformation rates in order to characterize the viscoelastic behavior proper of polymeric materials. It was observed that increasing the amount of glass fiber in the matrix leads to a stronger material and a consequent decrease of elongation to break. Additionally, abrasion tests were carried out using a Taber equipment in three distinct ...

International Nuclear Information System (INIS)

No-carrier-added astatine radionuclides produced in the "7Li-irradiated lead matrix were separated from bulk lead nitrate target by complexing At with insulin, followed by dialysis. The method offers simultaneous separation of At from lead as well as its complexation with insulin. The At-insulin complex might be a potential radiopharmaceutical in the treatment of hepatocellular carcinoma. The stability of At-insulin complex was checked by dialysis against deionized water and Ringer lactate (RL) solution. It has been found that the half-life of At-insulin complex is about #approx#12 h, when dialyzed against deionized water and is only 6 h, when dialyzed against RL solution having the same composition as blood serum. The 6 h half-life of this Insulin-At complex is perfect for killing cancer cells from external cell surfaces as the half-life of internalization of insulin molecule inside the cell is 7-12 h.

International Nuclear Information System (INIS)

The aim of this paper is offering a critical review of Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS), the approach of multi-elemental quantitative analysis of LIBS spectra, based on the measurement of line intensities and plasma properties (plasma electron density and temperature) and on the assumption of a Boltzmann population of excited levels, which does not require the use of calibration curves or matrix-matched standards. The first part of this review focuses on the applications of the CF-LIBS method. Quantitative results reported in the literature, obtained in the analysis of various materials and in a wide range of experimental conditions, are summarized, with a special emphasis on the departure from nominal composition values. The second part is a discussion of the simplifying assumptions which lie at the basis of the CF-LIBS algorithm (stoichiometric ablation and complete atomization, thermal equilibrium, homogeneous ...

Energy Technology Data Exchange (ETDEWEB)

Elastic and elasto-plastic modelling of indentation in CFRP cross-ply laminates has been performed. Detailed knowledge of the field solutions in the volume below the indentor forms the basis for the reported micromechanical interpretation of the observed damage in test specimens. The analysis shows that matrix cracks originate at sites of maximum tensile stress perpendicular to fibers. The predicted stress fields due to indentation show that stress concentrations occur in the interface between alternating plies. It is found that microcracking in this zone is a precursor to the observed failure. This analysis is supported by in-situ scanning electron microscopy during loading by a cylindrical indentor onto the laminate supported on a rigid substrate. The microscopy reveals microdamage in the region of interfacial tensile stress concentrations. The onset of indentation failure in these layered composites suggests that plastic interleaves would ...

International Nuclear Information System (INIS)

Immobilization of long-lived fission products (LLFP) such as radioactive Tc, Cs and Sr into #alpha#-SiAlON ceramics was evaluated using stable isotopes instead of radioactive isotopes, and the applicability of #alpha#-SiAlON ceramics as the inert matrix for transmutation of LLFP was investigated. In the case of single addition of SrO, SrCO_3, Cs_2CO_3 or ReO_2 to the starting materials, #alpha#-SiAlON, single phase was not formed after hot-pressing. When Y_2O_3 was added with SrO, SrCO_3 or Cs_2CO_3 to the starting materials (#alpha#-Si_3N_4, AlN and #alpha#-Al_2O_3) in optimum compositions, #alpha#-SiAlON single phase was obtained after hot-pressing at 1700degC or 1800degC. From the EDS analysis, Sr and Y were detected from grains. It is suggested that Y would assist the expansion of interstices of #alpha#-SiAlON lattice, resulting in the incorporation of Sr"2"+ into #alpha#-SiAlON lattice. In the case of Cs addition with Y, Cs was not ...

Science.gov (United States)

Not Available

DEFF Research Database (Denmark)

Udgivelsesdato: November-december

International Nuclear Information System (INIS)

... NUCLEAR FUEL CYCLE AND FUEL MATERIALS borophosphate glass

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

The analysis of complex fluids such as crude oils, fuels, vegetable oils and mixed waste streams poses significant challenges arising primarily from the multiplicity of components, the different properties of the components (polarity, polarizability, etc.) and matrix properties. We have recently introduced an analytical strategy that simplifies many of these analyses, and provides the added potential of linking compositional information with physical property information. This aspect can be used to facilitate equation of state development for the complex fluids. In addition to chemical characterization, the approach provides the ability to calculate thermodynamic properties for such complex heterogeneous streams. The technique is based on the advanced distillation curve (ADC) metrology, which separates a complex fluid by distillation into fractions that are sampled, and for which thermodynamically consistent temperatures are measured at ...

International Nuclear Information System (INIS)

The creep characteristics of alloy 800 at temperatures around 600"0C are greatly affected by the composition and treatments in the final stages of manufacture. Short-term and creep properties of alloy 800 at 600"0C are described for six melts covering the carbon range 0.054-0.078%, the titanium range 0.23-0.57% and the aluminium range 0.17-0.52%. The properties are related to the alloy chemistry and the microstructure. It is shown that homogeneously nucleated #gamma#'-precipitates are the main cause of low ductility in alloy 800 but there is also some influence of, for instance, grain boundary M_2_3C_6 films and discontinuous precipitation of Ni_3Ti or M_2_3C_6 in grain boundaries. The extent of #gamma#'-precipitation is controlled primarily by the (Ti+Al)-content. To avoid #gamma#' and ensure a high creep ductility the (Ti+Al)-content should be limited to 0.70-0.75% for alloy 800 with a carbon content of 0.054-0.078% and solution annealed at 1150"0C. A lower ...

International Nuclear Information System (INIS)

The matrix representations of Witten's and B-algebras of the field string theory in finite dimensional space of the ghost states are suggested for the case of Virasoro algebra truncated to its SU(1,1) subalgebra. In this case all algebraic operations of Witten's and B-algebras are realized in explicit form as some matrix operations in the graded complex vector space. The structure of string action coincides with the universal non-linear cubic matrix form of action for the gauge field theories. These representations lead to matrix conditions of theory invariance which can be used for finding of the explicit form of corresponding operators of the string algebras. (author).

International Science & Technology Center (ISTC)

New Composite Multifunctional Coatings Produced Using SHS-Electrodes

International Science & Technology Center (ISTC)

Development of Ceramic Composite Materials and Structural Elements for High-Temperature Nuclear Reactors

International Nuclear Information System (INIS)

This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope ...

International Nuclear Information System (INIS)

In the present work the hydrogen desorption properties of nanostructured magnesium hydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM) of elemental Mg powder under hydrogen are investigated. A profound effect of the particle size of synthesized MgH2 hydride on its hydrogen desorption characteristics measured by differential scanning calorimetery (DSC) has been found. All synthesized MgH2 powders are characterized by a double hydrogen desorption peak. Furthermore, below a certain threshold particle size the DSC desorption temperature of the peak doublet starts decreasing rapidly with decreasing of the mean hydride powder particle size (expressed as equivalent circle diameter-ECD). In contrast, the nanograin (crystallite) size of MgH2 does not seem to have apparent effect on the DSC desorption temperature. It is also observed that for powder particles smaller than some threshold value, X-ray diffraction shows the presence of two polymorphic ...

International Nuclear Information System (INIS)

In situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol.dm"-"3 Ce(NO_3)_3, La(NO)_3 and Sm(NO)_3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well-polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of the bulk conversion solutions upon the coatings formation was recorded. It is confirmed that the reduction ...

Energy Technology Data Exchange (ETDEWEB)

Particulate Reinforced Titanium matrix composites (PRTi) exhibit some improved specific mechanical properties in comparison with those of unreinforced titanium alloys as a result of the combination of the high strength and stiffness of ceramic particles with the toughness and damage tolerance provided by the metal matrix. The poor tribological properties of the titanium exclude titanium alloys from applications where wear resistance is required (brakes, rotating parts, sliding parts). The addition of ceramic particles improves the tribological properties of metals sensitive to adhesive and /or abrasive wear significantly. In this work, the wear resistance and the friction coefficient of Ti6Al-6V-2Sn reinforced with TiC particles and Ti6Al-4V reinforced with SiC particles (prototype material) are compared with the unreinforced alloys. Pin on disc and pin on ring tests were carried out against standard steel (100Cr6) as a ...

Energy Technology Data Exchange (ETDEWEB)

A metal matrix is inserted into a phase-change material to enhance the heat transfer during phase-change processes. The metal matrix tends to act like a heat transfer fin from the heated or cooled surface and to increase the effective thermal conductivity of the phase-change fluid. The scope of the study involves numerically modeling the heat transfer to and from constant-temperature cylindrical tubes surrounded by water during the freezing and melting processes. Comparisons of heat transfer with and without the metal matrix are made, with different porosities and densities of the metal matrix being examined. The results of this study are discussed in terms of the effectiveness of the metal matrix as a heat transfer enhancement device.

International Nuclear Information System (INIS)

Research highlights: ? Reports a high protection system for the alloy in corrosive environment. ? Describes an interfacial process with self-healing properties. ? Reports the influence of substrate pre-treatment in the coating performance. - Abstract: In this paper the interface of poly(vinylidene fluoride) coatings prepared by the dip coating method and HF-treated AZ31 magnesium alloy was evaluated. The best performance of this system in corrosion tests compared to ground, as-received and acetic acid cleaned substrates is related to an acid-base interaction at the interface and to interfacial reactions which resulted in a self-healing process. The protectiveness of the samples was investigated using impedance and immersion tests while the coating morphology and interface stability were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy and adhesion tests.

Energy Technology Data Exchange (ETDEWEB)

AZ31 magnesium alloy was friction-welded to AM60 and the microstructures and the friction welding process were studied. The microstructures changed near the weld interface. The AZ31 was refined to a grain size of several {mu}m near the weld interface. The nucleation occurred in the shear bands that were introduced during the welding process. On the other hand, the eutectic structure was deformed and the lamellar structure which was composed of {alpha}-Mg and Mg{sub 17}Al{sub 12} was formed near the weld interface in AM60 alloy. In the friction process, the adhesion and peel off occurred alternately between AZ31 and AM60. Eventually, bonding was completed during upset process. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Dynamic development of new grain boundaries was studied in compression of a magnesium alloy AZ31 with initial grain sizes (D{sub 0}) of 22 {mu}m and 90 {mu}m at a temperature of 673 K. Kink bands are evolved near corrugated grain boundaries and in grain interiors at low strains accompanied with new fine grains. Kink bands are developed often perpendicular to the basal plane. The boundary misorientation of kink band as well as the volume fraction of new grains increases rapidly with increasing strain and approaches a saturation value in high strain. New fine grains are developed faster with decrease in the D{sub 0}. It is concluded that new grain evolution is controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization (DRX). (orig.)

International Nuclear Information System (INIS)

A method is described for determination of aluminium, cadmium, cobalt, chromium, copper, calcium, magnesium, sodium, potassium, manganese, nickel, lead, strontium, zinc, titanium and vanadium in iron ore. After dissolution, a 1 gram sample of iron ore is applied to a column of AGI-X8 anion exchange resin (chloride form), in 100 ml of 7M HCl. Aluminium, chromium, calcium, magnesium, sodium, potassium, manganese, nickel, lead, strontium, titanium and vanadium are eluted with 7M HCl; iron, copper and cobalt are eluted with 0.5M HCl; cadmium and zinc are eluted with 2M HNO_3. Iron is subsequently removed from copper and cobalt by a solvent extraction with methyl isobutyl ketone. The elements are determined in the eluates by atomic absorption spectrometry, except for titanium and vanadium, which are determined spectrophotometrically.

UK PubMed Central (United Kingdom)

Recessive inactivating mutations in human matrix metalloproteinase 2 (MMP2, gelatinase A) are associated with syndromes that include abnormal facial appearance, short stature, and severe bone...Full Text Available

UK PubMed Central (United Kingdom)

Background and ObjectivesDisruption of the vocal fold extracellular matrix (ECM) can induce a profound and refractory dysphonia. Pulsed dye laser (PDL) irradiation...Full Text Available

International Nuclear Information System (INIS)

We consider the integrable structure of the quantum lattice W_N algebras. We introduce the ultralocal Lax matrix, and show that the Yang-Baxter relation is satisfied with a Z_N invariant R-matrix. (orig.).

Science.gov (United States)

If we decompose C1 using SVD the parameter covariance matrix can be inverted to ... However, we can analyze the parameter covariance matrix directly by ...

CERN Document Server

We propose a decoding algorithm for the $(u\\mid u+v)$-construction that decodes up to half of the minimum distance of the linear code. We extend this algorithm for a class of matrix-product codes in two different ways. In some cases, one can decode beyond the error correction capability of the code.

CERN Document Server

Using some modification of the standard fermion technique we derive factorized formula for spin operator matrix elements (form-factors) between general eigenstates of the Hamiltonian of quantum Ising chain in a transverse field of finite length. The derivation is based on the approach recently used to derive factorized formula for Z_N-spin operator matrix elements between ground eigenstates of the Hamiltonian of the Z_N-symmetric superintegrable chiral Potts quantum chain. The obtained factorized formulas for the matrix elements of Ising chain coincide with the corresponding expressions obtained by the Separation of Variables Method.

Science.gov (United States)

The estimated parameter covariance matrix is computed from8. ) ( ) 1. 2. T. T. ( ) ( )(. ?. ?. ?. Cov. E. ??. . ?. = . ? ? ? ? ?. ?. = ?. ?. ? ...

International Nuclear Information System (INIS)

... collective model hamiltonians iridium 187 matrix elements nuclear cores

DEFF Research Database (Denmark)

Udgivelsesdato: DEC

Energy Technology Data Exchange (ETDEWEB)

The basic objective of this project was to consider a large class of matrix computations with particular emphasis on algorithms that can be implemented on arrays of processors. In particular, methods useful for sparse matrix computations were investigated. These computations arise in a variety of applications such as the solution of partial differential equations by multigrid methods and in the fitting of geodetic data. Some of the methods developed have already found their use on some of the newly developed architectures.

Energy Technology Data Exchange (ETDEWEB)

In this paper the robust stability analysis of a single machine infinite bus system is investigated using interval matrix theory. Specifically the parameters of the power system stabilizer are considered as uncertainties in the system A matrix. The range of these parameters for which the system is Hurwitz stable is then found using interval matrix theory. (Author)

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Norwegian Open Research Archives (NORA)

Full Text Available

Science.gov (United States)

Not Available

UK PubMed Central (United Kingdom)

Vacuolar ion channels in guard cells play important roles during stomatal movement and are regulated by many factors including Ca²⁺, calmodulin, protein kinases, and phosphatases....Full Text Available

Science.gov (United States)

A number of alloys of zirconium have been investigated as part of a program aimed at improving the high-temperature tensile and creep strength of zirconium. These alloys include aluminum, beryllium, lead, magnesium, molybdenum, niobium, tantalum, tin, titanium, tungsten, vanadium, and zinc, binary and ternary alloys. The data indicate that aluminum, lead, molybdenum niobium, tin, titanium, tungsten, and vanadium can be used successfully to harden zirconium, and that aluminum, tin, titanium, and vanadium are particularly effective in maintaining the strength of zirconium at elevated temperatures.

Science.gov (United States)

A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations, however overall standard deviations depend on the skill of the student and their willingness to be careful and precise.

International Science & Technology Center (ISTC)

Thermodynamic Stable Metal Compositions for Improvement of an Operational Safety of Constructional Materials under Conditions of Multifactor Loadings of an Aggressive Environment

Science.gov (United States)

... Accession Number : ADD345858. Title : Nondestructive Testing of Polymeric Composite Sandwich Panels Via the Thermographic Halo,. ...