The effect of external convection on freezing in steady turbulent flow in a tube

An analysis is presented of the turbulent flow heat transfer and frozen deposit which occur in a tube that is cooled convectively on its external boundary sufficiently to create an internal frozen layer. The effects of Biot number, Prandtl number and inlet and outside temperatures on the initial freeze-free zone within the tube are shown. Additionally, the thickness profile of the freeze layer and the overall heat transfer rate which occur at steady state are determined and illustrated for a variety of representative cases.     

Thermal cycles effects on interlaminar shear strength (ILSS) and impact behaviour of carbon/PEI composites

In this paper, the effect of thermal cycle on the interlaminate shear strength (ILSS) and impact behaviour of unidirectional carbon fibre reinforced polyetherimide (PEI) matrix composites were studied. Samples were subjected to 100 thermal cycles (by immersing from boiling water (100°C) to ice water (0°C). The effects of thermal cycles were characterized by short beam shear and instrumented impact testers. Also Fractographic investigations were done using a scanning electron microscope (SEM). It is observed that the plastic deformations at the fibre/matrix and interlaminar interface as well as residual stresses lower the ILSS and flexural modulus of the material proportional with the number of thermal cycles. Up to the first 20 thermal cycles the material shows a brittle fracture with lower fracture energy, but after the 20th thermal cycles it is possible to observe that the material fractures with higher fracture energy at longer fracture time. A remarkable difference in the fracture morphology between the thermal cycled and un-treated materials has been observed. It is found that thermal cycles strictly affect the fracture morphology.     

Optimization of insulation thickness for external walls using different energy-sources

In countries that import most of their energy, like Turkey, energy saving and the effective usage of energy become much more important. Energy consumption for heating is too high in Turkey because buildings have almost no insulation. Also the high prices of heating energy in Turkey, emphasize the need for energy saving. Therefore, the optimum insulation-thickness of the external wall for the five different energy-sources (coal, natural gas, LPG, fuel oil and electricity) and two different insulation materials (expanded polystyrene, rock wool) are calculated for Denizli. The optimization is based on a life-cycle cost analysis. According to the results, the optimum has been obtained by using coal as the energy source and expanded polystyrene as the insulating material. When the optimum insulation-thickness is used the life cycle saving and payback period are 14.09 $/m² and 1.43 years, respectively.     

Intervention in risk factors and protection of target organs

The aim of this work is to review the role of the main risks factors in relation to cardiovascular diseases, and to evaluate the relative effectiveness of different preventive strategies. In the first part of the paper we summarize the historical background that allows us to understand the magnitude of this problem and its evolution. Secondly, we evaluate the significance of these strategies in the primary prevention of stroke and myocardial infarction, and how an intervention in one risk factor can have a greater significance for one of these events. But in any case, we must consider the whole benefit in each patient's health in our final evaluation of this intervention. Finally, we describe the strategies for hypertension and diabetes in order to reduce the incidence of end renal disease.     

Selenium-induced growth reduction in Brassica land races considered for phytoremediation

The earliest or patch stage of mycosis fungoides may present diagnostic difficulty both clinically and pathologically. The present study of the polymerase chain reaction (PCR) as a diagnostic tool in early mycosis fungoides was therefore undertaken, using a rapid PCR method for the detection of gamma- and beta-chain T-cell receptor (TCR) gene rearrangements in routine formalin-fixed, paraffin-embedded histological sections. Forty-two biopsies were studied from 26 patients with mycosis fungoides. Twenty-three skin biopsies with a clinicopathological diagnosis of early, or patch stage, mycosis fungoides were investigated. Of these, 18 (78 per cent) showed TCR-gamma or both beta- and gamma-chain TCR gene rearrangements. TCR gene rearrangements were shown in seven of the 14 plaque stage lesions (50 per cent) and also in the single case of tumour stage disease. Where gene rearrangements were identified, these were identical in all biopsies from an individual patient, irrespective of the site of the lesion, the disease stage, or the time lapse between the biopsies. The PCR is therefore a highly sensitive technique, which can be performed on routine pathological material, in cases where the diagnosis of early mycosis fungoides cannot be made with certainty on conventional histopathological and immunohistochemical grounds.     

Characteristics of safflower seed oils of turkish origin

Technological characteristics of oils extracted from seventeen varieties of safflower seeds (Carthamus tinctorius L.) of Turkish origin were investigated for their utilization prospects in the food industry and in other industrial sectors. Standard procedures were applied to determine the technological characteristics of seventeen varieties of safflower seeds and the safflower seed oils; fatty acid compositions were determined by gas-liquid chromatography. Results show that safflower seed oils are suitable both for food and industrial purposes.     

OPTIMIZATION OF PRESSURE SWING ADSORPTION EQUIPMENT PART I EFFECT OF EQUILIBRIUM CONSTANTS, AXIAL DIFFUSION AND INITIAL TO FEED CONCENTRATION RATIO ON COLUMN PRESSURIZATION AND PURGING

This paper consisting of two parts proposes a suitable method for the numerical optimization of pressure swing adsorption devices and comparison of multiple beds equipments with different piping and valves systems required to interconnect the adsorption cycle. In Part I a flexible isothermal and isobaric local equilibrium mathematico-physical model respecting axial dispersion and volumetric changes caused by adsorption has been formulated. The convergency of both the implicit form with central differences and explicit form with upwind differences is discussed. The effect of adsorption equilibrium on the oxygen concentration profile developed in the column at pressurization and the flow at constant pressure is simulated as well as the effect of axial dispersion. The creation of simple and shock concentration waves under various feeds to initial column oxygen concentration ratios is demonstrated. The proposed model is used also in Part II to compare the performance and gas purity of three types of two beds oxygen generators. On the bases of our local equilibrium model the condition for PSA equipment scale-up was proposed.     

通用管路零件参数化绘图程序的设计

给出了通用管路零件参数化绘图程序的设计方法，并利用ＡｕｔｏＣＡＤ绘出了完整的通用管件设计图．