다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

http://repositorium.sdum.uminho.pt/bitstream/1822/48763/1/1-s2.0-S037026931200857X-main.pdf

Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC

https://digital.csic.es/bitstream/10261/108964/1/experiment%20at%20the%20LHC.pdf

Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

The ATLAS Experiment at the CERN Large Hadron Collider

National Institute of Standards and Technology における超伝導研究及び生活

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Pressure and Thermal Characterisation of Dynamic Instabilities During Flow Boiling in Micro/Mini-Channels at Different Azimuth Orientations

The purpose of this paper is to determine the single phase heat transfer and pressure drop characteristics of an angled spiralling tape inserted into the annulus of a tube-in-tube heat exchanger. Experimental measurements were taken on four set-ups: a normal tube-in-tube heat exchanger used as a reference and three heat exchangers with different angled spiralling tape inserts. From the results correlations were developed that can be used to predict the heat transfer and pressure drop characteristics. It was concluded that the angled spiralling tape inserts resulted in an increasein the heat transfer and pressure drop characteristics as can be expected. INTRODUCTION Heat transfer enhancement is the process of improving the performance of a heat transfer system. It generally means increasing the heat transfer coefficient. Bergles[1] gives a comprehensive survey on heat transfer enhancement. According to him heat transfer enhancement has been studied since the first documented study of heat transfer. For example, Newton suggested in 1701 “… not in a calm air, but in a wind that blew uniformly upon it…”, which was an effective way of increasing the convective heat transfer. Bergles [1] states that Joule was the first to use second-generation heat transfer in 1891, when he reported significant improvement in the overall heat transfer coefficient for in-tube condensation of steam, when a helically coiled wire was inserted into the cooling jacket. The only second-generation enhancement device that was used in the 1800s with any regularity was the twisted tape insert. In 1896 Whitham, who inserted twisted tape inserts into the tubes of a fire-tube boiler, reported an increase of up to 18% in the boiler efficiency. In many cases heat transfer enhancement in tubes may be supplemented by heat transfer augmentation on the outside wall of tubes, as for tube-in-tube heat exchangers. An application is in vapour compression hot-water heat pumps where an axially coiled tube-in-tube heat exchanger [2] is used for heating water in the condenser of a hot-water heat pump. The condensing refrigerant may typically flow in the inner tube and the water to be heated in a counterflow direction in the annulus. Heat transfer enhancement on the inner or outer tube decreases the temperature difference between the condensing refrigerant and water to be heated, which is an advantage as higher hot temperatures may be delivered. In the case of water heating with a heat pump for which the heat transfer enhancement technique was developed, the refrigerant will flow in the inner tube and the water in the counterflow direction in the annulus. The purpose of this paper is to determine experimentally the heat transfer and pressure drop characteristics of single phase water in the annulus of the angled spiralling tape heat exchanger and to develop correlations that describe each of these characteristics.

Heat Transfer and Pressure Drop Characteristics of Angled Spiralling Tape Inserts in a Heat Exchanger Annulus

In this paper we apply constructal theory and design to present a three-dimensional geometric optimisation of cooling square pin-fins in forced convection of solid base material subject to constant temperature at the bottom. The main objective was to optimise the configuration in such a way that the peak temperature was minimised from the solid to the fluid of the pin fin. The cross–sectional area of solid base was fixed and the thickness of the solid is allowed to change. Three design cases are considered; the Case 1 has the pin-fins in a single row, Case 2 configuration has the pin-fins in two rows and Case 3 has configuration of the pin-fins in three rows arrangement. In all the three cases, the pin-fins geometric dimension are not uniform. The structure had four degrees of freedom as design variables: thickness of the solid base, hydraulic diameter of the pin, the height of the pin and pin spacing. The shape of the pin was not fixed but allowed to morph to determine the best configuration which gave the lowest thermal resistance. The cooling fluid (air) was driven by forced convection to the pin-fin by the stream velocity. An optimisation algorithm called Dynamic-Q was applied in order to search for the best optimal geometric configuration which improved thermal performance by minimising thermal resistance for a wide range of Reynolds number. The effect of applied Reynolds number and constant wall temperature on the optimal geometry was reported. There was unique optimal design geometry for a given Reynolds number. Results obtained show that the effects of Reynolds number on minimised thermal resistance are consistent with those obtained in the open literature.

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Numerical optimisation of square pin-fins for minimum thermal resistance with non-uniform design dimensions

A receiver is a central component of the parabolic trough collector system. Its design and state greatly affects performance of the entire collector system. In this paper a three dimensional numerical model of a receiver with an externally longitudinally finned absorber tube was developed to study the effect of fin dimensions on heat transfer and fluid flow performance characteristics. Results show that external longitudinal fins improve the performance of the receiver. Results further show that collector efficiency and useful heat gain will increase as the fin thickness and height increase and so do heat losses, glass temperature and maximum absorber temperature. A 6% increase in efficiency and a pressure drop of 370.65Pa/m are obtained for a finned absorber tube with lower dimensions 1.0 cm x 0.2 cm when compared to a non-finned tube larger in diameter by 1 cm. An increase in efficiency of 8% is obtained when the same finned absorber tube is compared with a non-finned tube of the same size.

/pdf/numerical-analysis-of-thermal-performance-of-an-externally-1doi4lw3gf.pdf

Numerical analysis of thermal performance of an externally longitudinally finned receiver for parabolic trough solar collector

In this experimental study, the Reynolds number limits of the transitional flow regime and friction factor characteristics were determined in the transitional flow regime of annuli. Isothermal and diabatic tests were conducted using four horizontal concentric annular passages with hydraulic diameters of 26.2, 23, 20.2 and 17 mm and respective diameter ratios of 0.327, 0.409, 0.386 and 0.483. The water in the annular passage was either heated or cooled at non-uniform temperature on the inner wall while the outer wall was insulated. The flow was both hydrodynamic and thermally developing, and the transitional flow was associated with mixed convection. The geometric size of the annular passage had a significant influence on the friction factors and Reynolds number span of the transitional flow regime. The annular geometric parameter that represent the geometric size of the annular passage was proposed and found to describe the friction factors well. Subsequently, correlations for predicting the friction factors in the transitional flow regime were developed.

Josua P. Meyer

Papers

Pressure and Thermal Characterisation of Dynamic Instabilities During Flow Boiling in Micro/Mini-Channels at Different Azimuth Orientations

Heat Transfer and Pressure Drop Characteristics of Angled Spiralling Tape Inserts in a Heat Exchanger Annulus

Numerical optimisation of square pin-fins for minimum thermal resistance with non-uniform design dimensions

Numerical analysis of thermal performance of an externally longitudinally finned receiver for parabolic trough solar collector

Pressure drop in the transitional flow regime of annuli associated with mixed convection