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The effect of temperature on the wear particles produced by vibratory cavitation erosion tests on Al-99.92 in distilled water was analyzed. Scanning electron microscope images of wear particles were obtained, forming a database for further analysis. This study showed that the variation of average particle size with temperature was very much similar to the variation of weight loss with temperature. The average particle size was maximum at 40[degrees]C, It was also observed that the average particle size was time dependent. The particle's morphology features revealed that the predominant erosion mechanism was fatigue failure, irrespective of the temperature. [DOI: 10.1115/1.4002069] Keywords: cavitation erosion, temperature, erosion particles, characterization of particles, erosion mechanism, Al-99.92

Piezoelectric thick high dielectric constant lead-zirconate-titanate (PZT)/PZT composite films are directly coated onto Al plates by using sol-gel spray technique. The results have shown that, for 2 mm thick aluminum plates, shear horizontal plate acoustic waves (PAW) are the best for the line defect detection, which have agreed well with those obtained by a finite-difference-based method.

Several theoretical analyses are conducted to explain the design and working of the high-Q, quartz thin film resonators that work at a frequency of 3.4GHz. The resonators are shown to exhibit excellent frequency-temperature behavior and hence are widely used in various different high-frequency timing devices.

A low-temperature technology is described for the fabrication of a polycrystalline silicon (poly-Si) thin-film transistor (TFT) with self-aligned metal electrodes (SAMEs). The effects of aluminum thickness on aluminum-induced crystallization (AIC) annealing temperature and time on the performance of a SAME poly-Si TFT are described.

The temperature dependence of the partitioning of [Al.sub.2][O.sub.3] between forsterite-rich olivine and Cr-rich spinels has been experimentally calibrated at 100 kPa between 1250 and 1450 [degrees]C under reducing conditions. For spinel with values of [Y.sub.Cr] between 0.07 and 0.69, and containing T([degrees]C) = 10 000/0.512 + 0.873[Y.sub.cr] - 0.91 ln([K.sub.D]) - 273 where [Y.sub.Cr] = Cr/(Cr + Al) in spinel in atomic proportions and [K.sub.D] = [Al.sub.2][O.sup.ol.sub.3]/[Al.sub.2][O.sup.sp.sub.3] in wt%. This equation reproduces the temperature of the experiment for the calibration data set within [+ or -] 22[degrees]C. Empirical tests suggest that this geothermometer has little pressure dependence within the range of pressures encountered in the crust and upper mantle. Keywords: Olivine, spinel, aluminum, thermometer, experiment

The extent to which the matrix ratio can be reduced for the rapid-heating, quenching and transformation (RHQT) [Nb.sub.3]Al wires is discussed. The non-Cu [J.sub.c] is improved by about 20% by the reduction of the matrix ratio when compared to conventional [Nb.sub.3]Al wires.

The characteristics of the [Nb.sub.3]Al strand through the rapid heating/quenching and transformation (RHQT) process are described. The studies have shown that the copper stabilized RHQT-processed [Nb.sub.3]Al strands can be used for application in high field accelerator magnets at 4.2 K.

A low-matrix-ratio [Nb.sub.3]Al wire is fabricated and the effects of the rapid heating/quenching (RHQ) current and the area reduction (AR) after the RHQ process are studied. The studies have shown that the optimum RHQ current to obtain high [J.sub.c] is the current at the higher edge of the plateau region and the AR process has affected the transformation process that has determined the quality of the A-15 phase.

The design of a superconducting magnet for DC induction heating of aluminum billets is described. The feasibility of cooling by liquid helium bath is confirmed for both Nb-Ti and Mg[B.sub.2] superconductors.

The article investigates the enhanced heat transfer characteristics of aluminum-foam heat sinks under impinging-jet flow conditions. The flow outlet height is stronger than the height of aluminum heat sinks and pore density.

A study was conducted to experimentally investigate the two-dimensional expansion and the elliptical temperatures of several laser-induced plasmas (LIPs) produced during the ablation of metallic samples. A weak LIP, both in terms of temperature and in terms of forward peaking is observed to be associated with the ablation of Al, while a hot and dynamic LIP is produced during the ablation of a low boiling point material such as Zn with significant angular spread and high temperature.

The growth of Al thin films on GaAs (100) on GaAs (100) substrates was investigated by molecular beam epitaxy. The results indicated that the Al film grown at increased temperature is Al(100)//GaAs(100) while the growth at 300 degree Celsius leads to a mixture phase of (100)Al[010]//GaAs[011] and (110)Al[001]//(100)GaAs[011].

In this paper, we present our recent experimental results on buoyancy- induced convection in aluminum metal foams of different pore densities [corresponding to 5, 10, 20, and 40 pores per in. (PPI)] and porosities (0.89-0.96). The results show that compared to a heated surface, the heat transfer coefficients in these heat sinks are five to six times higher. However, when compared to commercially available heat sinks of similar dimensions, the enhancement is found to be marginal. The experimental results also show that for a given pore size, the heat transfer rate increases with porosity, suggesting the dominant role played by conduction in enhancing heat transfer. On the other hand, if the porosity is held constant, the heat transfer rate is found to be lower at higher pore densities. This can be attributed to the higher permeability with the larger pores, which allows higher entrainment of air through the porous medium. New empirical correlations are proposed for the estimation of Nusselt number in terres of Rayleigh and Darcy numbers. We also report our results on novel finned metal foam heat sinks in natural convection. Experiments were conducted on aluminum foams of 90% porosity with 5 and 20 PPI with one, two, and four aluminum fins inserted in the foam. All of these heat sinks were fabricated in-house. The results show that the finned rueral foam heat sinks are superior in thermal performance compared to the normal metal foam and conventional finned heat sinks. The heat transfer increases with an increase in the number of fins. However, the relative enhancement is found to decrease with each additional fin. The indication is that there exists an optimum number of fins beyond which the enhancement in heat transfer, due to increased surface area, is offset by the retarding effect of over-lapping thermal boundary layers. Similar to normal metal foams, the 5 PPI samples are found to give higher values of h compared to the 20 PPI samples due to higher permeability of the porous medium. Future work is planned to arrive at the optimal heat sink configuration for even larger enhancement in heat transfer. [DOI: 10.1115/1.2229225]

The shear viscosities of Cl-bearing melts in the system [Na.sub.2]O-[Fe.sub.2][O.sub.3]-[Al.sub.2][O.sub.3]-Si[O.sub.2] were determined at temperatures of 550-950 [degrees]C in the range of [10.sup.8.5] to [10.sup.12.0] Pa s using the micropenetration technique. The compositions are based on addition of [Fe.sub.2][O.sub.3] or Fe[Cl.sub.3] to aluminosilicate glasses with a fixed amount of Si[O.sub.2] (67 mol%). Although there was loss of [Cl.sup.-] during the glass syntheses, no loss occurred during the viscometry experiments. It is to be expected that [Cl.sup.-] takes the structural position of [O.sup.2-] and thus reduces the polymerization of the melt structure, and therefore the viscosity of the melt; as F does. Our measurements show that the presence of [Cl.sup.-] increases or decreases the viscosity of the melts as a function of melt composition. In the present melts, at least 10% of the Fe exists as network-modifying or charge-balancing [Fe.sup.2+] whereas the rest exists as network-forming [Fe.sup.3+]. It is proposed here that the different effects of Cl on viscosity are due to the preferred [Cl.sub.-]-[Fe.sup.2+.sub.NBO] bonding together with the different structure of peralkaline and peraluminous melts. In peralkaline aluminosilicate melts, the addition of [Cl.sub.2][O.sub.-1] will destroy 2 NBOs and create one BO if [Cl.sup.-] bonds primarily to the [Fe.sup.2+] creating non-bridging O atoms. This would result in an increase in viscosity. In peraluminous melts, the addition of [Cl.sub.2][O.sub.-1] may result in Cl- bonds to the charge-balancing [Fe.sup.2+], creating 2 new tri-clusters [assuming ([Al.sub.3+], [Fe.sup.3+])[Si.sub.2][O.sub.5] tri-clusters exist]. The preference of [Cl.sup.-] to form bonds to the NBO-forming [Fe.sup.2+] is indicated by the small amount of [Cl.sup.-] soluble in the peraluminous melt structure in comparison to that soluble in the peralkaline structure. Keywords: Viscosity, melt structure, micro-penetration, chlorine, iron, aluminium, peraluminous, peralkaline

A simplistic method to direct the self-assembly of ZnO nanorods on flat and curved surfaces in hydrothermal synthesis by precoating the substrate with a thin film of aluminum (Al) is reported. The Al is transformed into hydrotalcite-like zinc-aluminum carbonates sheets in the alkali hydrothermal environment that promote a lattice-matched substrate for the growth of highly oriented ZnO nanorods.

The effect of high-temperature annealing on stress in Al(sub x)Ga(sub 1-x)N in different ambients and at different temperatures was discussed using ultraviolet micro-Raman spectroscopy. AFM results on a nitrogen-annealed cracked AlGaN layer indicate that additional crack formation and crack widening are two such morphological changes.

Discussing the strand fabrication and specifications, RHQ and subsequent transformation (T) heat treatment, property measurement, stabilizing investigations, and cabling for Nb3Al are reported. It is concluded that a short length of 12-strand Rutherford cable has been wound using ductile RHQ processed strand.

The hexagonal Al-rich high-pressure phases are members of a structural family with the same type of framework composed of double-ribbons of edge-sharing octahedra, but variably occupied trigonal and hexagonal channels. This family includes jaffeite, fluoborite, yeremeyevite, painite, and synthetic Ba indates. This kinship broadens the spectrum of elements potentially accommodated by these phases in the mantle. Keywords: Al-rich high-pressure phases, jaffeite, fluoborite, painite, framework of octahedra

Both alloy composition and avalanche region width have significant effects on the temperature dependence of breakdown voltage. Monte Carlo simulations show that alloy scattering reduces the temperature dependence of breakdown voltage, the effect is too small to account for the observations.

Several metastable phases form subsequently during heat treatment of Al-rich Al-Pt multilayers. The formation of these phases under different conditions is reported.

The preparation, as well as the electrical properties exhibited by the polyethylene glycol nanofluids containing carbon coated metal nanoparticles is analyzed. The thermal conductivity of the system is shown to be increase significantly with an increase in the filter loading frequency.

The surface thermal lensing effect is used for measuring thermal conduction across thin films optically. Thermal conductivity in gold films has dropped when the film thickness is reduced and the results for silver, tin and aluminum are presented.

Several temperature-dependent current-voltage measurements and the deep level transient spectroscopy technique are employed to explain the preparation and different electrical properties of the AlGaN/GaN heterostructures. The differences observed in the microstructure of the GaN buffer layers is shown to lead to the generation of different traps in the Schottky barrier diodes.

The deep level transient spectroscopy technique is employed to explain the different deep levels that are induced by the reactive ion etching in n- and p-type 4H- SiC compounds. The concentration of the defects is shown to decrease because of thermal oxidation.

Frequency-domain thermoreflectance is used for the characterization of thin metals films on low thermal diffusivity substrates. The thermoreflectance thermal conductivity values have agreed with the Wiedemann-Franz results for all the films, demonstrating that the method can be used for estimating electrical conductivity along with thermal conductivity for sufficiently thick films.

A postdeposition thermal treatment was applied to sputtered Al-doped zinc oxide films to study the effect of annealing time and temperature on the resistivity of the films. The reduction and change in carrier concentration in the films could be prevented by the use of capping layers with thicknesses of 40 nm or more.

A theoretical model is presented for equation of state (EOS) of aluminum with helium bubbles and the impact of helium bubbles on shock loading is examined. The bubble mass and concentration has affected the Hugoniot curve and the EOS model has minor significance, indicating that the model is not sensitive to the details of the helium EOS.

The metal-organic frameworks (MOFs) HKUST-1 are used as template to show that NaAl[H.sub.4] nanoclusters as small as eight formula units can be prepared. Simultaneous thermogravimetric modulated beam mass spectrometry have shown that the thermal decomposition mechanism of NaAl[H.sub.4] is complex and has involved processes such as nucleation and growth in addition to the normally assumed two-step chemical decomposition reactions.

Arrays of highly ordered ZnO nanowires are prepared on polycrystalline Al-doped ZnO (AZO) buffer layers prepared on p-Si substrates with assistance of a thermal deposition method. The low turn-on and threshold fields as well as the stable electron emission current have shown that the arrays of ZnO nanowires is considered in some electron field emission applications.

Molecular dynamics simulations are used for calculating the melting temperatures of pure nickel and pure aluminum at various system pressures using an embedded atom method type potential. The values obtained for the melting points of aluminum are shown to be higher, while for nickel it is lower.

The capacitance behavior of metal insulator metal (MIM) structures with [Zr.sub.1-x][Al.sub.x][O.sub.2] dielectrics and TiN metal electrodes is studied. The reactions between the oxidizing ambient and the bottom electrode during high-k deposition has resulted in structural changes and thus in generation of defects that cause a different electrical behavior of the two TiN/[Zr.sub.1-x][Al.sub.x][O.sub.2] interfaces at the top and the bottom electrode and a polarity asymmetry of the capacitance performance.

Several temperature dependent Hall effect measurements are conducted to determine the various defects observed in the virgin hydrothermally grown n-type ZnO samples. The results prove that the electron mobility in the compounds is affected by mainly two phenomenon, namely the ionized impurity-scattering and optical photon scattering.

The polycrystalline silicon (pc-Si) layers with variable grain sizes were constructed by changing the crystallization temperature of the AIC process and determine if larger grains resulted in better solar cells. The crucial impact of seed layer on the intragrain defect formation for the pc-Si layers based on AIC and epitaxial growth suggested that in addition to increased grain size, the intragrain quality of the material should also be considered in order to improve material quality and achieve high device performance.

The three-dimensional classical molecular dynamics simulation was used to examine the deposition and annealing behaviors of Al atoms on rough Cu (111) surface on the atomic scale. The significant intermixing between Al and Cu which rapidly occurs due to annealing at 700 K with decrease in the surface roughness provide insight into the exchange process of Al with substrate Cu during the initial stage of high temperature annealing.

Two simultaneous mechanisms of normal evaporation and phase explosion of nanosecond laser pulses were considered to theoretically study the laser ablation of Aluminum sample. The theoretical results of transition from the normal evaporation to the phase explosion are in good agreement with the experimental results of ablation due to the evaporation at low irradiance and the dominant phase explosion mechanism after a threshold intensity.

Glancing angle deposition (GLAD) experiments have shown that the nanorod morphology has displayed a chaotic instability with increasing surface diffusion and the measured rod width versus growth temperature has converged onto a single curve for all metals. The GLAD data has indicated that the effective mass transport on a curved surface is described by a single normalized activation energy that can be applied to all elemental metals.

The temperature dependence of the specific contact resistance in annealed Ti/Al/Ni/Au multilayers on [(N[H.sub.4]).sub.2][S.sub.x] treated n-type GaN is analyzed in a wide temperature range by the transmission line technique. A field emission model with a temperature-dependent effective SBH is responsible for the '25 min treated' sample in which metal/semiconductor interface potential pinch-off has occurred.