Investigation of the Performance of a Spiral‐Coil Finned Tube Heat Exchanger under Dehumidifying Conditions

In the present study, heattransfer characteristics of spiralcoil finned tube heat exchangers under dehumidifying conditions are investigated. A mathematical model of Ho et al. is modified by including fin efficiency. The derivation and solution methodologies are explained in detail. The effects of various inlet conditions of fluids flowing through the heat exchanger are discussed. The agreement of the model with the experimental data is satisfactory, with an average error of 1.2 and 4.0% for enthalpy and humidity effectivenesses, respectively.     

Influence of a Long Stay of the Heat‐Release Surface in Kerosene on the Critical Heat Flux in Boiling in It under Steady‐State and Step Conditions of Heat Release

Results of experimental investigations of the influence of a long stay of the heatrelease surface in kerosene on the first critical density of the heat flux in boiling under the steadystate and step conditions of heat release are given.     

Experimental Investigation of the Transparency of Optical Materials for UV Radiation under Conditions of Radiation–Gasdynamic Effect

The optical properties of a number of crystals such as quartz leucosapphire and calcium and barium fluorides are experimentally investigated in the spectral range = 110–250 nm under conditions of their direct contact with an intensely emitting gas–plasma medium. The broadband UV radiation of power density I ₀ 10⁶– 4 × 10⁷ W/cm² is generated with the aid of light-erosion and plasmadynamic injectors in a vacuum and gases of different chemical compositions. The possibility is demonstrated of effective transport of powerful fluxes of UV radiation through the given materials during the formation at their surface of a gas layer optically dense for the short-wave UV radiation.     

Identification of the Parameters of a Nested Cylindrical Heat Source under Stationary Self‐Heating of a Raw Material Mass of the Same Form

This paper describes a computer method for determining the coordinate of the center, the heatrelease power, and the sizes of a homogeneous internal cylindrical heat source in a stationary axially symmetric temperature field arising under selfheating of a plant raw material.     

Heat Exchange and Hydrodynamics of Two‐Phase Media under Conditions of Forced Motion in Porous Structures

Experimental data on the heat transfer and resistance of twophase media in porous structures are given. Results of calculating the thermal state of a heat exchanger with a porous insert that is cooled by a twophase flow are presented.     

Investigation of Thermal Resonance in Solution of a Two-Dimensional Singularly Perturbed Boundary-Value Problem of Nonstationary Heat Conduction with Nonlinear Boundary Conditions of the Stefan–Boltzmann Type

Data of the analytical-numerical parametric investigation of a singularly perturbed temperature field in the boundary layer of the side of a rectangle on which nonlinear boundary conditions of the Stefan–Boltzmann type are specified have been given. It has been established that a nonuniform initial temperature distribution of the Gaussian type causes the appearance of discontinuous traveling thermal waves in the corresponding boundary layer. A set of parameters for which the discontinuous traveling thermal waves, being superimposed, lead to a local nonlinear enhancement of the thermal field has been found. This effect can be considered as thermal resonance.     

Spectral Reflectivity of Ceramics of Cubic Zirconium Oxide on the Wavelength of 0.63 μm under Intense Surface Heating above the Melting Point and Subsequent Cooling

The experimental data on the normally hemispherical reflectivity of zirconium oxide ceramics are obtained for the wavelength of 0.63 m in the course of the first cycle of heating by concentrated laser radiation up to temperatures above the melting point and free cooling in ambient air. The obtained data are compared with analogous results of the second and subsequent cycles of heating and cooling. Analysis is made of the effect of the temperature field in the heated layer on the reflectivity and on the effective temperature measured by a pyrometer.     

Study on the Influencing Factors of Stakeholders Knowledge Sharing Behavior in Aircraft ProductDevelopment

Based on the individual level,influencing factors of stakeholders knowledge sharing behavior in aircraft product development are discussed,which are participant degree,sharing intention,and sharing capability.And the relationship of these factors between explicit knowledge sharing behavior and tacit knowledge sharing behavior are analyzed theoretically,some assumptions are put forward,and a theorittcal study model is established.Then,using a structural equation model,the assumptions are validated through principal component analysis and model fitting for 215 sample data.Lastly,the conclusion is gained that participant degree,sharing intention,and sharing capability all have a significant positive effect on the explicit knowledge sharing behavior and tacit knowledge sharing behavior in aircraft product development.     

Influence of the Preliminary Heating of А7075 Aluminum Alloy on the Strength of a SiC-Containing Composite Coating

Materials Science - We created composite coatings on the surfaces of A7075 aluminum alloy by the method of laser melting of the substrate and injection of highly dispersed silicon-carbide (SiC)...     

Numerical Simulation of the Treatment of Probe Current–Voltage Characteristics under Conditions of Anisotropic Velocity Distribution of Electrons

The results are given of numerical experiment in processing the current–voltage characteristics of a plane probe in a plasma with an anisotropic function of velocity distribution of electrons (EVDF). In order to find the first and second moments of EVDF expansion in Legendre polynomials, the known procedures are employed to develop and approve the computer codes for numerical reconstruction of these moments by the measured first derivatives of electron current to the probe for different orientations of the latter.     

Calculation of the Nonstationary, Nonlinear Three‐Dimensional Problem of Heat Conduction by the Finite‐Element Method in Continuous Laser Heating

The process of nonstationary highintensity laser surface heating of a threedimensional body in the shape of a rectangular parallelepiped by a continuous laser with a normal distribution of the power density in the heating spot has been investigated numerically with the finiteelement method. Consideration has been given to the process of formation of the heataffected zone and its geometry. Thermal cycles of zonal points and their characteristics have been investigated.     

Solution of Nonlinear Two‐Dimensional Differential Equations of Transfer with Discontinuity Boundary Conditions on the Surface of an Isotropic Semiinfinite Body in Its Heating Through a Circle of Known Radius

An analytical solution of the heatconduction problem is obtained by the method of linearization of a nonlinear equation of transfer and combined application of integral transforms to the linearized problem for an isotropic halfspace heated through a circular region 0 < r < R on its surface z = 0.     

Further Investigation on the Correlation between Ionization Potential and Superconductivity of Oxides

The relations of oxygen content, critical temperature TC and mean ionization potential < U0> of superconducting oxides are reported. We found that in oxides oxygen is the major element which governs their < U0> te values and thus oxygen content plays an jmportant role in their superconducting properties. As for Y(123)- and T1-systems oxygenation may improve their TC values, but for Biand Hg-systems oxygenation process is not so important. In Y(123), as the oxygen content increase results in the increase of TC upon < U0>to, while the substitution of Ba2+ by Sr2+ causes the decrease of TC upon < U0 >. These results may provide some clues about the superconductivity of oxides and support further that < Uo > is really a good criterion for oxide superconductivity. Two kinds of possible superconducting oxides are predicted in this paper according to the mean ionization potential criterion.     

Investigation of the effect of composition on microhardness and determination of thermo-physical properties in the Zn–Cu alloys

Zinc–copper of (99.99%) high purity alloys were directionally solidified upward with different compositions, C_o, Zn–(0.7,1.5, 2.4 and 7.37) wt.% Cu under two different solidification conditions (G = 3.85 K/mm, V = 0.0083 mm/s and G = 8.70 K/mm, V = 0.436 mm/s) using a Bridgman type directional solidification apparatus. The measurements of microhardness of directionally solidified samples were made by using a microhardness test device. The dependence of microhardness (HV) on composition was analyzed. According to these results, it has been found that the values of HV increase with the increasing Cu content (C_o). Variation of electrical resistivity (ρ) and electrical conductivity (σ) with the temperature were also measured by using a standard d.c. four-point probe technique. The enthalpy of fusion (ΔH) and specific heat (Cp) of the Zn–Cu alloys were determined from heating curve during the transformation from solid to liquid phase by using differential scanning calorimeter (DSC).     

Report on the working group on “critique of source concepts”

The Working Group on “Critique of Source Concepts” examined and evaluated the proposed reactor- and accelerator-based steady state neutron source concepts with regard to: performance and fit to user needs, technical feasibility and R&D requirements, capital and operating costs, and unique safety or siting issues. A more or less conventional, D₂O cooled and moderated research reactor, utilizing evolutionary advances in aluminum plate-fuel technology, can produce the desired 10¹⁶ n/cm² s flux levels in a large, accessible, user-friendly environment, with a relatively modest and low-risk R&D program, and at the lowest cost.