The pattern of counterurbanization in the Federal Republic of Germany, 1977-85

County-level data are used to examine the evidence for turnaround migration from urban to rural areas in the Federal Republic of Germany during the period 1978-1985. "The coexistence of suburbanization and counterurbanization for the 1978-85 time period is demonstrated. Young adults, 18-25 years of age, gravitated towards the urban cores of metropolitan areas and smaller urban areas. All the other age-groups moved mainly towards the outer suburbs of metropolitan areas, the suburbs of second-tier cities, and the rural counties. The two migration matrices indicate that counterurbanization at the level of regional planning areas was not present in 1977 but started in 1978 and it was present in 1983. At the same spatial level, evidence of a net gain of metropolitan areas from second-tier cities and rural areas is also provided for 1977. This pattern was reversed for the 1978-85 period."     

Welding of thin steel plates: a new model for thermal analysis

A mathematical model for the transient heat flow analysis in arc-welding processes is proposed, based on a unique set of boundary conditions. The model attempts to make use of the relative advantages of analytical as well as numerical techniques in order to reduce the problem size for providing a quicker solution without sacrificing the accuracy of prediction. The variation of thermo-physical properties with temperature has been incorporated into the model to improve the thermal analysis in the weld and heat-affected zones. The model has been evaluated using a five-point explicit finite difference method for analysing the welding heat flow in thin plates of two different geometric configurations. The temperature distribution closer to the heat source, primarily in the weld zone and the heat-affected zones, are predicted by the numerical technique. The thermal characteristics beyond the heat-affected zone are amenable to standard analytical techniques. The behaviour of the boundary condition in the model has been investigated in detail.Nomenclature q Rate of heat per unit thickness (Wm^–1) - d Plate thickness (m) - v Velocity of source (m s^–1) - t Time (s) - T Temperature value at the desired point (K) - T ₀ Initial temperature (K) - K Thermal conductivity (W m^–1 K^–1) - Density (kg m^–3) - c _p Specific heat (J kg^–1 K^–1) - Thermal diffusivity (m² s^–1) - n - Distance of point considered from the source (=x–vt) (m) - K ₀ Modified Bessel function of second kind and zero order - r Radial distance from the source (r=(x ²+y ²)^1/2) (m) - Model width (m) - a Plate width (m) - Distance from the source =(²+4 ×10^–4)^1/2 (m) - _n      

Application of the monte carlo method in the processing of experimental data on dynamic deformation of materials

The article presents a method of processing the recorded diagram of deformations vs time t for the purpose of determining the time-dependent change of strain rate and acceleration. The method is based on the utilization of data of statistical tests (the Monte Carlo method) and the least squares method applied to the deviations of the functions (t) from the experimental curve at the specified number of points.Translated from Problemy Prochnosti, No. 8, pp. 20–22, August, 1992.     

On the merits of ancient Chinese eye acupressure practices

Chinese schoolchildren and adults with strenuous visual tasks routinely perform massage-and-pressure exercises on selected acupressure points around the eyes. This practice, taught by the Jing-Luo school of acupuncture for more than 4000 years, is claimed to prevent and cure myopia and other afflictions thought to result from visual close work. A four-week pilot experiment was carried out with the aim of designing a proper study on the possible short-term benefits of eye acupressure programmes. Questionnaire data revealed that the subjects did experience various eye/vision symptoms as a result of the 90 min experimental task. This could not be verified by the measurements of accommodation precision and critical flicker fusion, nor could any beneficial effects of acupressure be seen over the four experimental weeks.     

Accurate solutions of the one-phase problem on the melting of a solid wedge

In quasisteady formulation accurate solutions are obtained for the problem of melting of a semiinfinite solid wedge in which its dihedral angles have an aperture angle t, where t is a simple fraction.Voronesh Technological Institute, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 63, No. 3, pp. 368–374, September, 1992.     

Effect of an increase in the nitrogen content of the working gas on the microstructure of reactive sputtered TiN thin films

TiN films were deposited on (100)-Si substrates by RF-reactive sputtering. The effects of processing parameters and substrate orientation on the stoichiometry, resistivity and microstructure of reactively sputtered TiN thin films were investigated. The RF-power was fixed at 50 W, and the nitrogen content in the working gas was adjusted so that target nitridation occurred at a relatively low nitrogen content, 2.6% N₂, in a fixed total flow rate of gases of 46.25 standard cubic centimetres (sccm). The N₂ percentage was varied from 2.6% to 15.4%. The films were continuous and 200 nm thick. Films deposited with the substrate facing the target exhibited 111-texturing, while films on substrates lying in the same plane of the target surface had 100-texturing. Both X-rays photoelectron spectroscopy and high-resolution detailed scans of the Auger electron energy spectrum were used for the stoichiometry determination. On the 100-textured TiN films, the N/Ti ratio was 1.0 at low N₂ flow rates; the N/Ti ratio rapidly increased with N₂ flow rate, and then levelled off. The films had resistivities ranging from 85 to 1340 µ cm, and the functional dependence of both N/Ti and the resistivity values behaved similarly with increasing N₂. X-ray single-line profile analysis of the 200-reflection indicated that the average crystallite size decreased and the average strain increased with increasing nitrogen content in the working gas. The Si/TiN structures were heat treated in the temperature range from 300 to 600°C in a quartz tube under 1 atm (10⁵Pa) of flowing high purity Ar gas. Heat treatment at 300°C did not affect the TiN film integrity, while treatment at 400–600°C resulted in void-type defects.     

Indices of the nutritional status of workers in the oil and gas production industry adapting to the extreme conditions of an arid zone

The authors studied actual nutrition and certain parameters of food (supply of vitamins A, E, C and the content of phospholipids, cholesterol, NEFA, triglycerides and cholesterol esters) for oil derrick installers working during summer at the "Mangyschlakneft" amalgamation. Incorrect structure of their nutrition and insufficient supply with vitamins A and C, revealed as the result of the study, necessitate rationalization of the nutrition for such workers.     

Methanol laser lines from torsionally excited co stretch states,and from OH-bend,CH3-rock,and CH3-deformation states

Using a quasi-CW CO₂ oscillator-amplifier combination with peak power 300 Watt, we have generated FIR laser emission in weak absorption bands of CH₃OH. 40 new lines are reported, and their wavelengths are measured with a relative accuracy of 5×10^?5. A total of 72 lines are assigned. 34 of these involve torsional n=1, 2, and 3 states of the CO stretch and the vibrational ground state. The remaining lines are associated with the CH₃-rock, OH-bend, and CH₃-deformation modes. The latter are located 1460 cm^?1 above the ground state, and are pumped by simultaneous vibrational excitation and torsional deexcitation.     

Collisionless spin waves in normal and superfluid3He

Standing spin-wave modes in liquid³He have been studied by cw NMR at Larmor frequencies of 1, 2, and 4 MHz and pressures of 0, 6.3, and 12.3 bar. The spin waves, which produce peaks in the NMR line, are visible at temperatures below 5 mK at zero pressure. With the assumption of a slightly simplified sample shape and no transverse spin relaxation at the walls, the theory of Leggett fits the spin-wave frequencies in the normal liquid very well, giving a value of the Fermi liquid parameterF ₁ ^a =–0.6±0.2 at zero pressure. The width of some of the peaks is larger than expected from other determinations of the quasiparticle diffusion time _D . This could be due to wall relaxation or to deviations from the assumed sample geometry. In the superfluid A₁ and A phases, where the data cannot be fitted to existing theories, the spin-wave modes are shifted in frequency and suffer additional damping as the temperature is decreased. At still lower temperatures in the B phase an inversion of the spin-wave spectrum from one side of the NMR line to the other is observed, agreeing quantitatively with the predictions of the 1975 theory of Combescot.