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

This paper investigates the cooling ability of embedded solid-state, high-conductive layers in electronics applications. A numerical approach is used to determine and compare steady-state thermal characteristics of this internal heat transfer augmentation scheme for two thermal boundary condition types. The boundary conditions under investigation represent cases where a rectangular three-dimensional solid-state heat generating volume is externally cooled from its surface in either one or two orthogonal directions. Various material property and geometric parameters are considered. The numeric results are compared with predictions of a traditional planar conductivity approach. It is shown that a planar approach used for obtaining the thermal characteristics of a laminated composite structure over-simplifies the problem and only supplies an indication of the ultimate ideal cooling efficiency, which may be achieved, with cooling layers. This paper presents trends, which may be used to predict thermal characteristics more accurately for conditions where no thermal interfacial resistance is present.

/pdf/cooling-layers-in-rectangular-heat-generating-electronic-xyt2jdc8ab.pdf

Cooling layers in rectangular heat-generating electronic regions for two boundary condition types: a comparison with a traditional approach

This paper documents the geometrical optimization of a micro-channel heat sink embedded inside a highly conductive solid, with the intent of developing optimal solutions for thermal management in microelectronic devices. The objective is to minimize the peak wall temperature of the heat sink subject to various constraints such as manufacturing restraints, fixed pressure drop and total fixed volume. A gradient based multi-variable optimization algorithm is used as it adequately handles the numerical objective function obtained from the computational fluid dynamics simulation. Optimal geometric parameters defining the micro-channel were obtained for a pressure drop ranging from 10 kPa to 60 kPa corresponding to a dimensionless pressure drop of 6.5 × 107 to 4 × 108 for fixed volumes ranging from 0.7 mm3 of 0.9 mm3. The effect of pressure drop on the aspect ratio, solid volume fraction, channel hydraulic diameter and the minimized peak temperature are reported. Results also show that as the dimensionless pressure drop increases the maximised dimensionless global thermal conductance also increases. These results are in agreement with previous work found in literature.

/pdf/mathematical-optimization-application-to-the-design-of-24iuk0gsc2.pdf

Mathematical optimization: application to the design of optimal micro-channel heat sinks

Synopsis As a result of the rising electrical energy costs in South Africa, a method was sought to reduce the overall electrical consumption of typical shaft systems. A typical shaft configuration was analysed and the primary energy consumers were identified. The ventilation fans for this system were found to consume 15% of the total energy of the shaft system. It was calculated that more than 50% of this energy is consumed by the shaft itself, more specifically, by the pressure losses that occur in the shaft as the ventilation air passes through it. In order to ensure that the theory being used for the evaluation of these shaft systems is accurate, a total of five shafts were instrumented and the actual pressure losses over the shafts plotted against time. These shafts were then analysed from a theoretical perspective. Finally, in order to ensure a thorough understanding of the behaviour of the ventilation air in shaft systems, the systems were simulated using computational fluid dynamics (CFD) techniques. There were significant discrepancies between the theoretical analysis and the CFD simulation during the initial comparisons. This discrepancy lessened as the complexity of the CFD models increased, until when the complete shaft was modelled using the full bunton sets, the pipes, and the flanges, the difference between the theoretical evaluation and the CFD simulation was small. This result demonstrates that the theory is insufficient and that the interrelated effect of the buntons and fittings has not been fully appreciated by current theory. The final phase of the work presented here was to evaluate the costeffectiveness of using different bunton shapes and shaft configurations. It is shown that the increase in the pressure losses and therefore the direct operating costs of the shaft can vary by as much as 80%, depending on the bunton configuration chosen. The placement of the piping in the shaft can increase the pressure losses, and therefore the direct operating costs of the shaft, by as much as 12%, depending on the placement of the piping in the shaft; this effect includes the use of flanges. The use of fairings on a large cage can reduce the resistance that the cage offers to the ventilation flow by as much as 30%. This, however, does not translate into a direct saving because as the cage moves through the shaft, the overall effect is transitory. These savings can be significant when the items highlighted in this work are applied correctly.

/pdf/optimizing-shaft-pressure-losses-through-computational-fluid-5cwelhnund.pdf

Optimizing shaft pressure losses through computational fluid dynamics modelling

The small-scale open and direct solar thermal Brayton cycle with recuperator has several advantages. These include low operation and maintenance costs and high recommendation. The main disadvantages of this cycle are the pressure losses in the recuperator and receiver, turbo-machine efficiencies and recuperator effectiveness, which limit the net power output of such a system. Thermodynamic optimization can be applied to address these disadvantages in order optimize the receiver and recuperator and to maximize the net power output of the system at any steady-state condition. The dynamic trajectory optimization method is applied to maximize the net power output of the system by optimizing the geometries of the receiver and recuperator, limited to various constraints. Standard micro-turbines and parabolic dish concentrator diameters of six to eighteen meters are considered. An optimum system geometry and maximum net power output can be generated for each operating condition of each micro-turbine and concentrator combination. The results show how the irreversibilities are spread throughout the system optimally, in order for the system to produce its maximum net power output. It indicates that the optimum operating point of a micro-turbine is at the point where the internal irreversibilities are approximately three times larger than the external irreversibilities.Copyright © 2011 by ASME

Josua P. Meyer

Papers

Cooling layers in rectangular heat-generating electronic regions for two boundary condition types: a comparison with a traditional approach

Mathematical optimization: application to the design of optimal micro-channel heat sinks

Optimizing shaft pressure losses through computational fluid dynamics modelling

Maximum Net Power Output of the Recuperative Open and Direct Solar Thermal Brayton Cycle

Experimental investigation on the viscosity, electrical conductivity and ph of sio2-ethylene glycol nanofluids