Heat pipes and their use in technology

Heat pipes may be employed as temperature regulators, heat diodes, transformers, storage batteries, or utilized for transforming thermal energy into mechanical, electric, or other forms of energy. General concepts were established for the analysis of the transfer process in heat pipes. A system of equations was developed to describe the thermodynamics of steam passage through a cross section of a heat pipe

Power law correlations in galaxy distribution and finite volume effects from the Sloan Digital Sky Survey Data Release Four

We discuss the estimation of galaxy correlation properties in several volume limited samples, in different sky regions, obtained from the Fourth Data Release of the Sloan Digital Sky Survey. The small scale properties are characterized through the determination of the nearest neighbor probability distribution. By using a very conservative statistical analysis, in the range of scales [0.5,~30] Mpc/h we detect power-law correlations in the conditional density in redshift space, with an exponent \gamma=1.0 \pm 0.1. This behavior is stable in all different samples we considered thus it does not depend on galaxy luminosity. In the range of scales [~30,~100] Mpc/h we find evidences for systematic unaveraged fluctuations and we discuss in detail the problems induced by finite volume effects on the determination of the conditional density. We conclude that in such range of scales there is an evidence for a smaller power-law index of the conditional density. However we cannot distinguish between two possibilities: (i) that a crossover to homogeneity (corresponding to \gamma=0 in the conditional density) occurs before 100 Mpc/h, (ii) that correlations extend to scales of order 100 Mpc/h (with a smaller exponent 0 < \gamma <1). We emphasize that galaxy distributions in these samples present large fluctuations at the largest scales probed, corresponding to the presence of large scale structures extending up to the boundaries of the present survey. Finally we discuss several differences between the behavior of the conditional density in mock galaxy catalogs built from cosmological N-body simulations and real data. We discuss some theoretical implications of such a fact considering also the super-homogeneous features of primordial density fields.Comment: 13 pages, 19 figures, to be publsihed in Astronomy and Astrophysic

Extension and estimation of correlations in Cold Dark Matter models

We discuss the large scale properties of standard cold dark matter cosmological models characterizing the main features of the power-spectrum, of the two-point correlation function and of the mass variance. Both the real-space statistics have a very well defined behavior on large enough scales, where their amplitudes become smaller than unity. The correlation function, in the range 0<\xi(r)<1, is characterized by a typical length-scale r_c, at which \xi(r_c)=0, which is fixed by the physics of the early universe: beyond this scale it becomes negative, going to zero with a tail proportional to -(r^{-4}). These anti-correlations represent thus an important observational challenge to verify models in real space. The same length scale r_c characterizes the behavior of the mass variance which decays, for r>r_c, as r^{-4}, the fastest decay for any mass distribution. The length-scale r_c defines the maximum extension of (positively correlated) structures in these models. These are the features expected for the dark matter field: galaxies, which represent a biased field, however may have differences with respect to these behaviors, which we analyze. We then discuss the detectability of these real space features by considering several estimators of the two-point correlation function. By making tests on numerical simulations we emphasize the important role of finite size effects which should always be controlled for careful measurements.Comment: 18 pages, 27 figures, accepted for publication in Astronomy and Astrophysic

Значення непрямого державного регулювання та саморегулювання у забезпеченні якості

В сфере регулирования качества во всём мире всё большее значение приобретают средства непрямого государственного регулирования и саморегулирования. Добровольными признаются стандарты и процедуры оценки соответствия (сертификация), расширяются масштабы деятельности саморегулируемых организаций. Статья посвящена исследованию развития этих процессов в Украине.In the whole world the means of the indirect state regulation and self-regulation have more and more significance in the sphere of the quality. The standards and procedures of conformity by assessment are considered to be voluntary, the scales of the self-regulation organization activity, in particular, consumer protection, are increased. The article is devoted to the research of these processes development in Ukraine

Some results of cislunar plasma research

The main results of plasma cislunar investigations, carried out during Luna-19 and Luna-22 spacecraft flights by means of dual frequency dispersion interferrometry, are briefly outlined. It is shown that a thin layer of plasma, with a height of several tens of kilometers and a maximum concentration of the order 1,000 electrons/cu cm exists above the solar illuminated lunar surface. A physical model of the formation and existence of such a plasma in cislunar space is proposed, taking into account the influence of local magnetic areas on the moon

Total Site Integration for Coke Oven Plant

The process of benzene distillation and process of coal tar distillation being typical for East European countries is analyzed in this paper. The pinch analysis method was selected to perform a reconstruction project. According to principles of pinch analysis, new network diagrams are designed and capacity of heatexchange equipment is calculated. The using of "Total Site Profiles" showed the feasibility of heat pump integration. Heat pump integration allowed to reduce the external hot utilities usage on 368 kW and cold utilities usage on 368 kW. This project let to decrease the external hot utilities usage on 23 % and cold utilities usage on 24,13 %, and also offered the way of step-by-step retrofit of the plant

Total Site Integration for Coke Oven Plant

The process of benzene distillation and process of coal tar distillation being typical for East European countries is analyzed in this paper. The pinch analysis method was selected to perform a reconstruction project. According to principles of pinch analysis, new network diagrams are designed and capacity of heatexchange equipment is calculated. The using of "Total Site Profiles" showed the feasibility of heat pump integration. Heat pump integration allowed to reduce the external hot utilities usage on 368 kW and cold utilities usage on 368 kW. This project let to decrease the external hot utilities usage on 23 % and cold utilities usage on 24,13 %, and also offered the way of step-by-step retrofit of the plant