Features of the Diffusiophoresis of Aerosol Droplets with Allowance for the Influence of the Evaporation (Sticking) Coefficient and Internal Flows

A new theory of diffusiophoresis of large volatile spherical aerosol droplets, which is a further development of the previous investigations, has been formed. Account has been taken of the influence of the evaporation coefficient of the droplet liquid, the surfacetension coefficient variable along the droplet surface, and internal flows in the droplet on the diffusiophoresis velocity. The formulas obtained enable one to directly find the velocity of motion of single large aerosol droplets in a binary gas mixture inhomogeneous in concentration.     

A novel X-ray technique for inspection of steel pipes

The corrosion-induced material loss in crude oil carrying steel pipelines was originally studied by making use of the backscatter X-ray technique. The steel thickness can be determined by studying the density profile of the backscatter intensity vs. the depth location of a voxel. There are, however, some practical limitations to the above method, and a new method for evaluating steel thickness, namely, the transcatter technique is described. This technique uses the intensity of the beam which is transmitted by the pipe wall and subsequently scattered by the hydrocarbon inside the pipeline. The thickness is evaluated using three techniques, namely, the sequential technique, the dual angle technique, and the reference technique. Of the three techniques, the sequential technique has been studied in detail. The mathematical equations and experimental results related to the transcatter technique show that the thickness can be measured with an accuracy of better than 10% for a nominal steel thickness of 8 mm with a measurement time of several minutes.     

The crystallization of the amorphous alloy Fe40Ni40P14B6

The isothermal transformation behaviour of the metallic glass Fe₄₀Ni₄₀P₁₄B₆ between 320 and 400° C is described. Crystallization occurs by a eutectic mechanism to form Fe-Ni austenite and a body-centred tetragonal phase which is isomorphous with Fe₃P and Ni₃P. The eutectic crystals have a barrel shape such that the c-axis of the tetragonal phase is parallel to the barrel axis. The orientation relationship between the two phases is 1 1 0T 1 1 0 and 0 0 1T 1 1 2. The austenite phase contains (1 1 1) twins.     

Raising the precision in evaluating short-duration frequency deviations of UHF generators

Conclusions Methods for measuring short-duration UHF generators' frequency drifts with a preliminary lowering of the tested signal's frequency have a larger error for the same instability of reference generators than the methods described in this article. The compensation method analyzed above improves the precision of measurements by an estimated amount of pk/2k.The compensation method error depends on the precision of the electronic circuits used in the testing and on the interrelationships of the circuit components, in particular on the value of multiplication factor p. Taking into consideration the possibility of variations in the factors, the maximum error of the method can be evaluated at 3–6%, provided well-adjusted standardized units are used in the meter.Translated from Izmeritel'naya Tekhnika, No. 5, pp. 35–37, May, 1967.     

Parallelization of the Volterra algorithm for linear optimal open loop control

If and when the time variation of optimal controls of a linear system subject to known forces is required, they can be obtained by the computationally advantageous open loop Volterra formulation (as opposed to the costlier Riccati formulation). For the computation, the Volterra equation is discretized in the time domain via such schemes as trapezoidal integration or SIMPSON's rule and the resulting linear system is solved to obtain the control vector values at discrete time points within the control timeT. In the case of very large order systems (degrees of freedom 5000) a parallel technique is absolutely neccessary, and this paper enunciates an efficient parallel stratagem with efficiencies in the range of 80% and 100%. The algorithm uses s + 1 processors, s being the number of intervals within the control timeT, and typically each processor characterizes one time point.The research described herein was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration (NASA)     

Equipment for checking dielectric losses in silicon matrices with dielectric insulation

Conclusions The industrial apparatus Omega-2 described above employs an indirect method of measuring the leakage current in the pockets of a silicon matrix with dielectric insulation. The basic error of the apparatus does not exceed 5%.By regulating the voltage applied to the pocket, we would be able to select the structure needed for creating devices with high breakdown voltages and low reverse currents.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 61–62, January, 1979.     

Thermal compensation of reference voltage sources with silicon stabilitrons

Conclusions The above technique of computing the copper compensation resistance provides a satisfactory precision for maintaining the parameter. A very small error can be attained in carrying out this experiment, since it is possible to eliminate the dispersion of factor for a specific diode specimen.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 46–48, August, 1968.     

Simulation of the procedure for measuring the gravitational constant on an Earth satellite

A simulation is described for measuring the newtonian gravitational constant G in the SEE space experiment. Two methods are examined for estimating G: the two-point method and the integral one. When the two-point method is used, to provide an error not more than G/G 1·10 ^–6 requires path measurements to be performed with an error of not more than 1·10^–8 m=/50 ( is the green line wavelength). In the integral method, the same error in estimating G is attained with an error of measurement different by two orders of magnitude, 1·10^–6 m.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 3–5, January, 1994.     

Analytical Solution of the Nonhomogeneous Kinetic Equation in the Problem of Isothermal Slip of a Rarefied Gas Along a Solid Spherical Surface

An analytical method of solution of a halfspace boundaryvalue problem for the nonhomogeneous kinetic Boltzmann equation with a collision operator in the form of an ellipsoidalstatistic model in the problem of isothermal slip of a rarefiedgas flow along a solid spherical surface is presented. Within the framework of the considered model, a correction to the coefficient of isothermal slip that is due to the wall curvature is obtained. Comparison with literature data is made.     

Microstructure and mechanical properties of rapidly quenched L20 and L20+L12 alloys in Ni-Al-Fe and Ni-Al-Co systems

Ductile L2₀-type wires and+L1₂-type duplex wires with high strengths and large elongation in the Ni-Al-Fe and Ni-Al-Co ternary systems have been manufactured directly from the liquid state by an in-rotating-water spinning method. The wire diameter was in the range 80 to 180m and the average grain size was 2 to 4m for the wires and 0.2 to 1.0m for the+ wires. _y, _f and _p of the wires were found to be about 360 to 760 MPa, 560 to 960 MPa, and 0.2 to 5.5%, respectively, for the Ni-Al-Fe system, those of the+ wires were about 395 to 660 MPa, 670 to 1285 MPa, and 3.5 to 17%, respectively, for the Ni-Al-Fe system, and about 260 to 365 MPa, 600 to 870 MPa, and 4.0 to 7.0%, respectively, for the Ni-Al-Co system. Cold-drawing caused a significant increase in _y and _f and the values attained were about 1850 and 2500 MPa, respectively, for Ni-20Al-30Fe and Ni-25Al-30Co wires drawn to about 90% reduction in area. The high strengths, large elongation and good cold-workability of the melt-quenched and+ compound wires have been inferred to be due to the structural change into a low-degree ordered state containing a high density of phase boundaries, suppression of grain-boundary segregation and refinement of grain size.     

Effect of thickness on the fracture characteristics of fetal membranes

The mechanical characteristics of the chorioamniotic membrane were evaluated with a new burst test apparatus by rupturing 35 specimens that were taken from a sample of seven afterbirths. Strength, stiffness, toughness, and ductility were measured. Mechanical characteristics did not change significantly with variation in thickness. While ductility should not correlate with thickness, the lack of a significant increase in strength, stiffness and toughness with an increase in thickness is most unusual and requires an explanation. Subsequently, an additional experiment, which was designed to ascertain the mechanical stability of membrane specimens with prolonged exposure to air, showed a dramatic increase in stiffness as membranes were allowed to dry. The increase in stiffness indicates that strength and toughness also increase with drying, provided that ductility remains constant. Thus, the degree of hydration of the membrane, which is reflected in thickness, regulates mechanical characteristics. The increase in the water content of certain amniotic layers has a lubricating effect on the amnion-chorion interface. This lubrication increases as term approaches. Thus, hydration must increase as gestation progresses, and strength, stiffness, and toughness must decrease until the membrane is weak enough to rupture at the end of gestation. Thus, hydration must increase as gestation progresses, and strength, stiffness, and toughness must decrease until the membrane is weak enough to rupture at the end of gestation.     

The development of strength in reaction sintered silicon nitride

The development of strength in reaction sintered silicon nitride has been investigated by determining the elastic moduli, fracture mechanics parameters, strengths and critical defect sizes of silicon compacts reacted to various degrees of conversion using static or flowing nitrogen. The relationship between each property and the nitrided density is shown to be independent of the green silicon compact density but is influenced by the nitriding conditions employed. Young's moduli, rigidity moduli and strengths vary linearly with the nitrided density. After an initial period when increases may occur, the critical defect sizes in both static and flow materials decrease continuously with increasing nitrided density, although at any particular density they are larger in material produced under flow conditions. A model is suggested for the development of the structure of reaction sintered silicon nitride involving the development of a continuous silicon nitride network within the pore space of the original silicon compact. The experimental data are discussed in terms of the proportion of silicon nitride which contributes effectively to the continuous network.     

Nomogram for determining the error in differential-manometer flowmeters

Conclusions It is possible by means of the above technique to plot nomograms for all the formulas of GOST 3720-60 for determining the basic error in differential-manometer flowmeters.The error in determining the basic error of differential-manometer flowmeters from nomogram _N does not exceed 0.1%.     

Stress relaxation in zirconium carbide. Report 2. Mechanisms of stress relaxation. The relationship of the processes of creep and relaxation

Mechanisms of stress relaxation in ZrC_1.00 (d=6–35 .m) in the area of the ductile-to-brittle transition temperature (1600–2200C) are considered. It is established that in the 1800–2000C range for ZrC_1.00 with grain sizes of 6 and 14–35 m, respectively, stress relaxation occurs as the result of pure grain boundary slip while at higher temperatures by intragranular cross slip. It is shown that creep in the steady stage and stress relaxation in ZrC_1.00 with grain sizes of 6–35 m are controlled by different physical processes, which makes impossible obtaining for these materials of data on stress relaxation by conversion with use of information on steady creep.Translated from Problemy Prochnosti, No. 2, pp. 55–60, February, 1994.     

Thermodynamic investigations of liquid Bi-Na and Sn-Na alloys by coulometric titration using β″-alumina

The following double galvanic cell was assembled and the thermodynamic properties of liquid Bi-Na and Sn-Na alloys, and the ion selectivity of -alumina during coulometric titration, were investigated. Mo, Na(I)¦-alumina¦M-Na(I), Mo [I] M-Na(I)¦-alumina¦Au + Au₂Na, Mo [II] (M = Bi or Sn) where M-Na(1) and Au + Au₂Na were used as the common electrode and reference electrode, respectively. Sodium was coulometrically titrated through the -alumina electrolyte of cell I both ways, and the EMFs were measured. It was found that no ion-exchange reaction occurs between the liquid alloys and the -alumina, and only Na was transferred in the -alumina during coulometric titrations. The thermodynamic properties of liquid Sn-Na and Bi-Na alloys were found to be in agreement with the literature.     

Nonequilibrium Molecular Dynamics Simulations of Shear Viscosity: Isoamyl Alcohol, n-Butyl Acetate, and Their Mixtures

Nonequilibrium, NVT, molecular dynamics (NEMD) simulations were used to obtain the shear viscosity, , of isoamyl alcohol, n-butyl acetate, and their binary mixtures at 35°C and 0.1 MPa. The fluids were modeled using rigid bonds, rigid bond angles, appropriate torsional potentials, pairwise-additive Lennard–Jones dispersion interactions between united-atom sites, and partial point charges located at atomic centers. Simulations were performed at different shear rates, , and values obtained at =0 are compared to experimental values. Two methods are commonly used to extrapolate pure-fluid simulated data to zero shear, (0). The applicability of these two methods to mixtures of polar fluids was examined in this study. It was found that linear extrapolation with respect to ^1/2 can lead to ambiguous (0) results for some mixtures because of a curvature in the data that shows no observably distinct change in rheology. On the other hand, a log–log plot of () versus is consistently very linear with a distinct change from shear-thinning to Newtonian rheology at lower shear rates. The latter method is recommended for consistency sake, even though agreement between experiment and (0) values was better with the former method. This agreement was 12 and 21% for the two methods, respectively. A negative bias in the simulated values is attributable to the united-atom model.     

Knudsen molecular flow in a channel with a small temperature difference at its ends

The thermomolecular pressure difference (TPD) of helium, argon, and krypton is measured in a packet of glass capillaries for temperatures 273 and 293 K at their ends in a 10–100 range of Knudsen numbers.Notation exponent of the thermomolecular pressure difference effect - Kn Knudsen number - rarefaction parameter - Q_T reduced thermal creep flux - Q_P reduced Poiseuille flux - C(_t) Cercignani-Lampis scattering kernel - R specular scattering kernel - (1 – ) fraction of specular reflection - _t accommodation coefficient of the tangential momentum - P_c, P_h gas pressure in the cold and hot volumes, respectively - coefficient of dynamic viscosity - m mass of gas molecules - k Boltzmann constant - D, L the capillary diameter and length, respectively Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 5, pp. 719–724, May, 1988.     

Low-temperature synthesis of binary cuprates from hydroxide precursor

Binary cuprates of Sr₂CuO₃₊ and SrCuO₂ have been synthesized at low temperatures below 500 °C under various values of partial oxygen-pressure by thermal decomposition of hydroxide precursors, Sr₂Cu(OH)₆ and SrCu(OH)₄, respectively. The tetragonal Sr₂CuO₃₊ ( 0.3) is obtained by the heat-treatment at 400 ° C and 0.2 atm. The value of appears to be independent of and unchangeable. On the other hand, the orthorhombic Sr₂CuO₃₊ ( 0) is obtained by the heat-treatment at 400 °C in flowing gas of N₂. For 0 < < 0.2 atm, a mixture of the tetragonal and orthorhombic phases is obtained. The orthorhombic SrCuO₂ is obtained by the heat-treatment at 500 ° C in flowing gas of N₂, although the tetragonal SrCuO₂, namely, the so-called infinite-layer compound is not obtained.     

Thermal Expansion and Isothermal Compressibility of TlIn1 – xNdxSe2 (0 ≤ x≤ 0.08) Crystals

The thermal expansion coefficient () and isothermal compressibility ( _T ) of TlIn_{1 – x} Nd _x Se₂(0 x 0.08) crystals were measured between 77 and 400 K. In the range 77–160 K, both and _T increase with temperature, the increase in being much steeper. At higher temperatures, and _T change very little. The observed composition dependences of and _T are interpreted in terms of energy-band structure.