Martensite aging kinetics in the Cu-10 wt.%Al and Cu-10 wt.%Al-10 wt.%Ag alloys

The martensite aging kinetics in the Cu-10 wt.%Al and Cu-10 wt.%Al-10 wt.%Ag alloys was studied using microhardness measurements, classical differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and in-situ high-temperature X-ray diffractometry (XRD). The results for the Cu-10%Al alloy indicated a process dominated by the martensite ordering assisted by migration of quenched-in vacancies and followed by the consumption of the α phase. For the Cu-10%Al-10%Ag alloy the dominant process is the consumption of the α phase associated with a decrease in the ordering degree of the martensitic phase.     

Industrial experiences of bending fatigue strength in table liner for cement mill

A table liner for the vertical roller mill has been used to grind natural limestone. Unexpected fatigue failure accidents have occurred during portland cement manufacturing process. The design life of a table liner is 4 × 10⁷ cycles, but the actual fatigue life of a table liner is 2 × 10⁶ to 8 × 10⁶ cycles. The fatigue crack of a table liner initiates from the outside edge of the grinding path of the limestone. When such a crack occurs, the table liner has to be replaced, and this requires 30% of the total maintenance cost of the vertical roller mill. Therefore, this study examines the fatigue failure of a table liner by plane‐bending fatigue test, stress measurement test, finite element analysis and fatigue fracture analysis.     

An instrument for mass analysis using a laser

An apparatus has been constructed that will give a complete elemental analysis of a solid sample in the size range 10^–8 to 10^–10 g. The beam from aQ-switched ruby laser is focused on to the sample, and the ions produced are used to give time resolved spectra. Analysis of several types of sample is described, illustrating the capabilities and limitations of the instrument.     

Determination of H2O and CO2 concentrations in fluid inclusions in minerals using laser decrepitation and capacitance manometer analysis

Water and carbon dioxide concentrations within individual and selected groups of fluid inclusions in quartz were analyzed by using laser decrepitation and quantitative capacitance manometer determination. The useful limit of detection (calculated as ten times the typical background level) is about 5 x 10(-10) mol of H2O and 5 x 10(-11) mol of CO2; this H2O content translates into an aqueous fluid inclusion approximately 25 micrometers in diameter. CO2/H2O determinations for 38 samples (100 separate measurements) have a range of H2O amounts of 5.119 x 10(-9) to 1.261 x 10(-7) mol; CO2 amounts of 7.216 x 10(-10) to 1.488 x 10(-8) mol, and CO2/H2O mole ratios of 0.011 to 1.241. Replicate mole ratio determinations of CO2/H2O for three identical (?) clusters of inclusions in quartz have average mole ratios of 0.0305 +/- 0.0041 1 sigma. Our method offers much promise for analysis of individual fluid inclusions, is sensitive, is selective when the laser energy is not so great as to melt the mineral (laser pits approximately 50 micrometers in diameter), and permits rapid analysis (approximately 1 h per sample analysis).     

On the electron microprobe analysis of structured magnetic thin films

The electron microprobe analysis of sputtered FeSi and sputtered or electroplated NiFe films with different structures is reported. The layer thicknesses are between 5 × 10² and 10⁴ Å. The sources of error of a wavelength dispersive spectrometer are compared with those of an energy dispersive spectrometer. Both have been tested by variation of the spectrometer geometry, the inclination of the thin film plane, and the chemical composition, surface roughness and thickness of the films. The calibration was made by X-ray fluorescence and atomic absorption analysis.     

Effect of additive-oxide amount on sintering of Si3N4 with Y2O3 and Nd2O3

The effect of additive amount on the gas-pressure sintering of silicon nitride is investigated. Silicon nitride containing 0.5 to 10 mol % (SN10) of equimolar Y₂O₃-Nd₂O₃ is fired at 1600 to 1900 °C for 4 h in 10 M Pa N₂ gas. A small amount of oxide (1 mol %; SN1) is effective for densification as well as a larger amount of oxide (6–10 mol %) when fired at 1900 °C. Composition analysis of sintered specimens indicates that SN1 densifies through a small amount of SiO₂-rich liquid-phase, whereas SN10 densifies by way of a large amount of additive-oxide-rich liquid phase.     

COSY,eine neue Forschungsanlage mit Ultra-Hochvakuum-Technologie

The report shows that the development, construction and later successful operation of UHV facilities in the pressure range of ≤10^?10mbar is not possible without a highly sensitive nondestructive testing technique. The example of the large technical research facility COSY is used to demonstrate that the leakage rates (≤10^?10mbar · I · s^?1) and surface purities required can only be achieved by strict compliance with fundamental UHV production conditions and by the rigorous application of helium leak detection techniques and mass-spectrometric residual gas analysis.     

Thermal expansion and relaxation-crystallization kinetics of metallic glass Co63Ni6Fe4V2Si10B15

The conventional dilatometric technique is applied to study the thermal expansion of the metallic glass Co₆₃(FeNi)₁₀V₂Si₁₀B₁₅ with cylindrical samples rolled from ribbon. The heatingrate effect on expansion and differential thermal analysis (DTA) is investigated. The non-linear region of the temperature variation curves of relative elongation all show a broad peak and a distinct peak which correspond to those in DTA. The broad peak in DTA resolves into two peaks: the first one is associated with the glass transition which is interpreted as a quasi-first-order transformation. On comparing with X-ray diffraction analysis, the crystallization is determined to be a two-stage process in which Co(4F) precipitation is a controlling factor.     

State-of-the-art in analytical characterization of high purity solid samples by different spectroscopic methods

Facilities and some results of several spectroscopic methods which have potential applications in the field of analysis of solid high purity substances and which have been elaborated in Russia, will be discussed in this paper. Laser nondispersive atomic fluorescence method with glow discharge cathode sputtering atomiser, may be used for trace element determination as well as a tool for the investigation of technological processes, viz. deposition of thin films. Investigations on reduction of a background level in the new hollow cathode ion source for mass-spectrometry have been carried out. Laser mass spectrometry with tandem laser mass reflectron is successfully designed and applied for gaseous impurities determination in high pure silicon with limit of detection of 10⁻³–10⁻⁵ ppm wt. Several results of the layer-by-layer and bulk trace analysis of solids by high resolution mass spectrometry with radio frequency powered glow discharge ion source with the limits of detection at 10⁻¹–10⁻³ ppm wt will be presented here. The traditional arc and spark emission technique still finds considerable use. One of the examples considered in the paper is the analysis of metalfullerenes. To overcome the calibration problem the fluorination process inside the electrode crater using zinc fluoride has been investigated.     

Influence of reynolds and prandtl numbers on the effectiveness of intensification of heat transfer in tubes

The results are presented of an experimental investigation of intensification of heat transfer in tubes in the range of Re numbers 1.5 · 10³-10⁵ and of Pr numbers 0.7–50, in flows of gases, water, and a waterglycerin mixture. An analysis is made of the mechanism of heat transfer when the flow is rendered turbulent by artificial means.     

Quantitative analysis of boron in solids by autoradiography

A non-destructive method of quantitative analysis for boron is described. The method, which depends on the use of a plastic film to record tracks from the ¹⁰B(n, )⁷Li reaction, is in general applicable to any solid material but is here described in detail for the analysis of ferrous alloys. Boron contents from 1 ppm to 10% may be determined, and the technique may be applied also to microanalysis of individual features such as precipitates and grain-boundaries in the metal structure.     

Theoretical analysis of the impact of Rayleigh noise on the performance of distributed Raman temperature sensors

We present a theoretical model to analyze the impact of Rayleigh noise on Raman distributed temperature sensors (RDTS), which use the anti-Stokes and Stokes light or anti-Stokes component only as the demodulation signals. Based on this model, the effects of Rayleigh noise on temperature accuracy, sensitivity, and resolution are investigated both at only one point and in a section of the fiber. The analysis indicates that for RDTS demodulated by anti-Stokes light only, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.25°C on the assumption that the Rayleigh noise accounts for 10% of the anti-Stokes intensity. Moreover, for RDTS demodulated by Stokes and anti-Stokes light, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.2°C assuming that the Rayleigh noise in two paths is equal to 10% of the intensity of anti-Stokes and Stokes light. The analysis demonstrates that the impact of Rayleigh noise on sensing capacities of RDTS is non-negligible, thus providing a major contribution to the elimination of Rayleigh noise in RDTS.     

A tissue equivalent proportional counter filled with a mixture of tissue equivalent gas and 3He for neutron monitoring

Tissue equivalent proportional counters (TEPC) allow the measurement of the ambient dose equivalent H(*)(10) in mixed fields. IRSN has been studying the design and the response of a TEPC in terms of neutron H(*)(10). First, a cylindrical counter was filled with propane gas at a low pressure. H(*)(10) measured in monoenergetic neutron fields underestimated the reference (>50%) at low energies (< 500 keV). A small amount of (3)He was then added to the gas in order to increase the response. The underestimation observed decreased but the results (> 40%) were not totally complying with the objectives (< 20%). Finally the choice was made to improve the analysis of the microdosimetric spectra y.d(y) in order to identify the energy of the incident neutrons. The analysis allows a better estimate of H(*)(10). The aim of this article is to describe the TEPC and the effect of these methods of optimisation.     

X-ray diffraction line broadening of cadmium oxide produced by cadmium hydroxide decomposition

A precise analysis of X-ray diffraction line broadening produced by cadmium oxide obtained by the thermal decomposition of Cd(OH)₂ is described. The influence of experimental conditions is considered. It is shown, using different methods of analysis, that the broadening of the reflections is due to size and microstrains effects, with a mean apparent size of 6 nm in a direction perpendicular to (1 10) planes.     

Synthesis characterization and hydrogen absorption studies of the composite materials La2Mg17–x wt% LaNi5

The composite materials La2Mg17–x wt% LaNi5 have been synthesized with various values of x, and the hydrogenation behaviour of these materials has been extensively studied. The as-synthesized materials were activated by heating the materials at about 360±10°C temperature under a hydrogen pressure of 33 kg cm-2 for nearly 6 h. The maximum hydrogen storage capacity was found to be 5.3 wt% for the composite material La2Mg17–10 wt% LaNi5 at 400±10°C temperature. This is one of the very highest storage capacities known so far. The initial rate of hydrogen absorption of La2Mg17–10 wt% LaNi5 was found to be 20 cm3 g-1 min-1 (at 400±10°C temperature). In order to elucidate the influence of LaNi5 addition, which significantly accelerated the hydriding rate and hydrogen storage capacity of La2Mg17, structural–microstructural characterization and chemical analysis of the composite materials employing X-ray diffraction, scanning electron microscopy and energy dispersive analysis of X-rays techniques have been carried out.     

A 100000-A high precision on-site measurement calibration devicefor heavy direct current

A 100000-A, high precision device of the magnetic modulation current comparator type, which can be used in industrial heavy direct current systems for online calibration and measurement, is presented. Testing of the comparator indicates that its current ratio accuracy is 5×10^-5, and that measurements of voltage with a standard resistor achieve an accuracy of 5×10^-4. These are slightly degraded to 3×10^-4 for on-site calibration and 1×10^-3 for on-site measurement. The device, which has a toroidal configuration, can be opened for each installation on a busbar, with a variation in accuracy of less than 2×10^-5. Its magnetic shielding renders it insensitive to magnetic fields up to 1×10^-2 Tea. Its accuracy is better by a factor of two than that of similar industrial measuring devices. The principle of operation and the characteristics of the comparator, the double shielded design, and an analysis of its errors are discussed     

Surface physical and chemical changes of pure iron after molybdenum ion implantation and their effects on the tribological behaviour I: Physical and chemical analysis

Molybdenum ions generated by a metal vapour vacuum arc (MEVVA) ion source were implanted into pure iron at doses of 1 × 10¹⁷ and 3 × 10¹⁷ ions cm⁻² with an extraction voltage of 45 kV. Auger electron spectroscopy (AES) sputtering depth profiles, X-ray photoelectron spectroscopy (XPS) analysis, X-ray diffraction (XRD) analysis, microhardness and the residual stress of the implanted specimen were studied. The results show that molybdenum atoms exist in the implanted layer at a maximum concentration 20 at.%. A new phase (Fe₃C) is formed in the specimens implanted higher doses due to carbon incorporation during sputtering of the natural oxide film from the implanted surface. The Fe₂Mo phase is formed in both dose regimes. Residual compressive stresses of 310 and 560 MPa were measured on the surfaces of the specimens after molybdenum ion implantation at 1 × 10¹⁷ and 3 × 10¹⁷ ions/cm² respectively due to a local expansion of the lattice in the near-surface region. Due to the existence of residual compressive stress and the formation of the new phases, the microhardness of pure iron specimens was increased from 264 to 325 and 333 kgf mm⁻² by molybdenum ion implantation at 1 × 10¹⁷ and 3 × 10¹⁷ ions cm⁻² respectively.     

Diagnostics of degradation processes induced by pulsed electric signals at the aluminum-silicon interface

Thermal conditions in an aluminum metallization stripe deposited onto a single crystal silicon substrate have been studied during the passage of single rectangular electric pulse with a current density of j < 8 × 10¹⁰ A/m² and a duration of τ = 100–1000 μs. Based on the results of this analysis, a method of diagnostics of the state of metallization contact systems and determination of the conditions of their safe operation is proposed.     

Time-interval Statistics of the Spectrum Characterizing a Polydisperse Medium

Abstract

A complete and exact theoretical analysis of the time-interval statistics of the two-peaked spectrum characterizing a polydisperse medium is presented here for the first time. This analysis is based on the unique analytic one-fold generating function derived recently in [10]. The analysis is valid for macromolecules of arbitrary shape and size undergoing uncoupled translational and rotational diffusion motions. Conditions leading to an easy resolution of the time-interval-statistics data and the modifications required under the spatial coherence effect are also discussed.     

Computerized glow curve deconvolution applied to high dose (102–105 Gy) TL dosimetry

First order kinetic analysis is applied in a computerized deconvolution technique to the thermoluminescence (TL) glow curve of LiF:Mg,Ti (TLD-100) over the dose range 1–10⁵ Gy. The computer routine, based on a nonlinear least-squares method, is capable of simultaneously deconvoluting as many as eight overlapping glow peaks (24 independent parameters). The ability to separately follow the dose response of the high temperature glow peaks is shown to extend the usefulness of TL dosimetry to 10⁵ Gy and beyond.