Materials Literature
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In en effort to increase the structural efficiency of aerospace vehicles, r ecent designsx have been making use of low density, high etrength, brittle materials. Ae a result, the vehicle structure ie considerably more suscept ible to ,damage due to impact loadings. Aircraft impact loadings can be divided into two type…
The preparation of powder plays an important role in the manufacture of sintered ferrites. The characteristics of the ferrite powders are influenced by method of preparation which subsequently influence the properties of finished products. Various chemical methods such as conventional coprecipitation, spray drying, py…
Abstract Different forms of oriented inclusions in single crystals of potassium dihydrogen phosphate (KDP) grown by gel method and from aqueous solutions are reported. Small rod like chain and channel types of liquid inclusions are illustrated. These inclusions are oriented along 〈001〉, 〈011〉 and 〈010〉 directions and…
In the event of a loss-of-coolant accident in water-cooled reactors, the Zircaloy-2 cladding is subjected to a rapid increase in temperature and stress in an oxidizing environment. Accurate numerical values of creep parameters are thus required for use in tube deformation models that predict fuel cladding behavior dur…
The thermodynamic properties of the thorium-oxygen system at high temperatures have been investigated by means of mass effusion, mass spectrometric, and transpiration techniques over compositions ranging from the congruently vaporizing composition to the lower phase boundary composition. A very sharp decrease in oxyge…
The surface self-diffusion coefficient of silver was measured by the grain boundary grooving method in atmospheres with various oxygen potentials. In an argon atmosphere with PO2=10−11 Pa, the surface self-diffusion coefficient can be expressed by the following equation:Ds=0.249exp(−166kJ/mol·RT)m2⁄s(973–1073K).This e…
The paper discusses the interference studies carried out on Williams domains in the case of N-(p-propoxybenzylidene) p-pentylaniline. Measurements of the periodic variation of the orientation of the director in the nematic medium are reported.
Abstract A metastable modification of SrSiO3 was formed at 850–910 °C from mixed powders prepared by the alkoxy-method. Crystallization isotherms were best described by the first-order equation and the activation energy was determined as 130 kcal/mol. The kinetics on the transformation of metastable to stable SrSiO3 w…
The detailed crystal structure of anhydrous aluminum sulfate, Al2(SO4)3, has been determined from X-ray powder diffraction with well crystallized powder sample. The grain was rhombohedron in shape and surrounded by crystal-faces of {0 1 1 2} planes. The unit cell was assigned to hexagonal symmetry with a0=8.032Å, c0=2…
The thermal behavior of mono (2-ethylhexyl) phthalate (monoester) was investigated in a batch system over the temperature range from 80 to 250°. After a 12 hr reaction period, around 7% of the monoester was decomposed at 80°. The decomposition reached 50% at 150°and 90% at 250°. The reaction products were bis (2-ethyl…
Tests were made of Kevlar® fiber blends of 5, 10, 15, and 20% with cotton. The processing efficiency of cotton/Kevlar blends compared favorably with that of blends of cotton with 15, 25, 35, and 50% of polyester or 15% nylon. Lower twists were required for yarns spun from the cotton/Kevlar blends for optimum strength,…
Helium permeability, diffusivity, and solubility have been measured for sodium, potassium, rubidium, and cesium germanate glasses, and for one series of sodium-potassium germanate glasses. In each case, the helium permeability and diffusivity exhibit minima in the property-composition curves. These minima shift to gre…
Single crystals of K 5 Nd(MoO 4 ) 4 were grown from the melt by the Czochralski method. Dielectric anomalies were observed in both ε a and ε c around 300–500°C. The maximum values of the dielectric constants and the corresponding temperature depend on frequency. The birefringence shows a small anomaly at 485°C. The ph…
The probelm of joining ODS alloys by welding for high temperature use has limited their application in industry. To date, all wedling processes employed have resulted in loss of dispersoid through agglomeration or slagging off and the development of grain boundaries perpendicular to the existing structure of the mater…
Specialized sulfur concretes were developed by the Federal Bureau of Mines as a result of research for the beneficial utilization of sulfur in construction materials. Materials were developed for use in acid and salt corrosive environments where portland cement concrete has been found to deteriorate. Because the miner…
In order to clarify the fluidity of interdendritic liquid contributing to the formation of macrosegregation and the castability in an ingot, an artificial hole was made in the zone of coexistence of the solid and the liquid so as to make only the liquid flow into the hole. Then the relation among the fluidity of the l…
Progress since 1955 in the technology of zirconium and its alloys is reviewed primarily from an applications viewpoint. A number of favorable features have been uncovered as their use broadened as well as problem areas which required accommodation in design or lifetime. Zirconium technology has reached its present sta…
Two methods are described for producing high-velocity liquid impacts. The first involves projecting a jet of liquid at a stationary target while in the second specimens are fired at suspended drops. An objective of the study was to place the jet method on a quantitative basis. Detailed studies of jets, using high-spee…
Abstract The ability of sodium molybdate to inhibit corrosion of mild steel is demonstrated using laboratory and field test data. Initial evidence is also presented indicating that molybdate inhibits the corrosion of copper and aluminium. Environmental aspects including fish toxicity data are discussed as is the likel…
Linear poly (ethylene glycol) (PEG) is able to complex with neutral molecular Iodine in the solution state and in solid state, to produce I− 3 ions detectable by conventional spectroscopy and by photoacoustic spectroscopy (PAS). This behavior of PEG is another instance of its ability to mimic the complexation features…