This paper presents a thermal study of cavity receiver designed for Fresnel-type linear solar collector (LFC). The utilizes two-dimensional computational fluid dynamics (CFD) model implemented in ANSYS Fluent. behavior air inside the Fresnel is extensively examined. consists trapezoidal with set six parallel absorber tubes, through which circulates. has aluminum reflectors on inner walls and gl...

Examples of conformal dynamo maps have been presented earlier [Phys Plasmas 14(2007)] where fast dynamos in twisted magnetic flux tubes in Riemannian manifolds were obtained. This paper shows that conformal maps, under the Floquet condition, leads to coincidence between exponential stretching or Lyapunov exponent, conformal factor of fast dynamos. Unfolding conformal dynamo maps can be obtained...

This work is devoted to the study of asymptotics gravitational field primary particles with nonzero rest mass. These are structurally composed two closed “null strings” (thin tubes a massless scalar field) in shape circle, and they formed gas null strings as result interaction. It shown that on time scales much larger than one complete cycle oscillation forming particle, or at distances dimensi...

In this paper‎, ‎we study the class of rings in which every $P$-flat‎ ‎ideal is flat and which will be called $PFF$-rings‎. ‎In particular‎, ‎Von Neumann regular rings‎, ‎hereditary rings‎, ‎semi-hereditary ring‎, ‎PID and arithmetical rings are examples of $PFF$-rings‎. ‎In the context domain‎, ‎this notion coincide with‎ ‎Pr"{u}fer domain‎. ‎We provide necessary and sufficient conditions for‎...

Refrigerant maldistribution severely deteriorates the heat transfer performance of a microchannel evaporator. Compared with refrigerant distribution among flat tubes along header, microchannels in tube airflow direction has barely been paid attention. In this paper, mathematical model evaporator’s composed vertically placed parallel was developed. The evaluated and its influence on between air ...

in 2001, s. bulman-fleming et al. initiated the study of three flatness properties (weakly kernel flat, principally weakly kernel flat, translation kernel flat) of right acts $a_{s}$ over a monoid $s$ that can be described by means of when the functor $a_{s} otimes -$ preserves pullbacks. in this paper, we extend these results to$s$-posets and present equivalent descriptions of weakly kernel po...

introduction: transhiatal esophagectomy is a widely accepted approach for palliative resection of subcarinal esophageal cancers. this study was designed to evaluate the necessity of routine thoracostomy tube insertion in this technique.  methods: this descriptive study was conducted on 123 consecutive patients with esophageal cancers undergoing transhiatal esophagectomy from march 2001 to febru...

this paper investigates axial compression process of multi-layered tubes with circular cross-section under the axial loading in the quasi-static condition using experimental method. some specimens are prepared in seven different groups, namely; empty carbon/epoxy composite tubes, solid carbon/epoxy composite rods, empty copper tubes, composite tubes with silicon sealant filler, concentrically s...

background: the presence of heavy metals in the environment especially in water supplies have caused many concerns because of their toxicity and non-degradability. hexavalent chromium (cr) is one of the most toxic metals which is used in many industries, so it is essential to remove it from industrial wastewater. in this study, we made a comparison between different adsorption isotherms in the ...