scholarly journals Modeling of the Radial Heat Flow and Cooling Processes in a Deep UltravioletCu+Ne-CuBr Laser

2009 ◽  
Vol 2009 ◽  
pp. 1-16
Author(s):  
Iliycho Petkov Iliev ◽  
Snezhana Georgieva Gocheva-Ilieva ◽  
Krassimir Angelov Temelkov ◽  
Nikolay Kirilov Vuchkov ◽  
Nikola Vassilev Sabotinov
Keyword(s):  
Power Density ◽  
Copper Ion ◽  
Nonlinear Boundary Conditions ◽  
Simple Expression ◽  
Air Cooling ◽  
Gas Temperature ◽  
Laser Tube ◽  
Copper Bromide ◽  
Forced Air ◽  
The One

An improved theoretical model of the gas temperature profile in the cross-section of an ultraviolet copper ion excited copper bromide laser is developed. The model is based on the solution of the one-dimensional heat conduction equation subject to special nonlinear boundary conditions, describing the heat interaction between the laser tube and its surroundings. It takes into account the nonuniform distribution of the volume power density along with the radius of the laser tube. The problem is reduced to the boundary value problem of the first kind. An explicit solution of this model is obtained. The model is applied for the evaluation of the gas temperature profiles of the laser in the conditions of free and forced air-cooling. Comparison with other simple models assumed constant volume power density is made. In particular, a simple expression for calculating the average gas temperature is found.

scholarly journals Air circulation in a gastrointestinal light source box and endoscope in the era of SARS-CoV-2 and airborne transmission of microorganisms

2021 ◽  
Vol 09 (03) ◽  
pp. E482-E486
Author(s):  
Stanislas Chaussade ◽  
Einas Abou Ali ◽  
Rachel Hallit ◽  
Arthur Belle ◽  
Maximilien Barret ◽  
...  
Keyword(s):  
Light Source ◽  
Cooling System ◽  
Air Cooling ◽  
Airborne Transmission ◽  
Plastic Tube ◽  
Care Workers ◽  
Air Cooling System ◽  
Forced Air ◽  
Air Circulation ◽  
Closed Environment

Abstract Background and study aims The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system. Methods We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax. Results The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded. Conclusions Changes are necessary to prevent airborne transmission. Exclusive use of an external CO2 pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.

scholarly journals Hyperbolic Center of Mass for a System of Particles in a Two-Dimensional Space with Constant Negative Curvature: An Application to the Curved 2-Body Problem

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 531
Author(s):  
Pedro Pablo Ortega Palencia ◽  
Ruben Dario Ortiz Ortiz ◽  
Ana Magnolia Marin Ramirez
Keyword(s):  
Negative Curvature ◽  
Dimensional Space ◽  
Center Of Mass ◽  
Simple Expression ◽  
Two Dimensional ◽  
Constant Negative Curvature ◽  
Euclidean Case ◽  
System Of Particles ◽  
Material Points ◽  
The One

In this article, a simple expression for the center of mass of a system of material points in a two-dimensional surface of Gaussian constant negative curvature is given. By using the basic techniques of geometry, we obtained an expression in intrinsic coordinates, and we showed how this extends the definition for the Euclidean case. The argument is constructive and serves to define the center of mass of a system of particles on the one-dimensional hyperbolic sphere LR1.

FORCED-AIR COOLING AFTER AIR-SHIPMENT DELAYS ASPARAGUS DETERIORATION

2003 ◽  
Vol 26 (1) ◽  
pp. 43-54 ◽  
Author(s):  
E. LAURIN ◽  
M.C.N. NUNES ◽  
J-P. EMOND
Keyword(s):  
Air Cooling ◽  
Forced Air

scholarly journals Design of Forced Air-cooling Structure for Elevated Temperature PEMFC

2010 ◽  
Vol 4 (3) ◽  
pp. 464-469
Author(s):  
Xiaoliang Zheng ◽  
Daijun Yang ◽  
Kan Tao ◽  
Hao Zhang ◽  
Jianxin Ma
Keyword(s):  
Elevated Temperature ◽  
Air Cooling ◽  
Forced Air

A Spray-Droplet Model for Diesel Combustion

1969 ◽  
Vol 184 (10) ◽  
pp. 28-35 ◽  
Author(s):  
J. Shipinski ◽  
P. S. Myers ◽  
O. A. Uyehara
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Heat Release ◽  
Engine Speed ◽  
Chamber Pressure ◽  
Gas Temperature ◽  
Single Droplet ◽  
Burning Rates ◽  
Burning Model ◽  
The One

A spray-burning model (based on single-droplet theory) for heat release in a diesel engine is presented. Comparison of computations using this model and experimental data from an operating diesel engine indicate that heat release rates are not adequately represented by single-droplet burning rates. A new concept is proposed, i.e. a burning coefficient for a fuel spray. Comparisons between computations and experimental data indicate that the numerical value of this coefficient is nearly independent of engine speed and combustion-chamber pressure. However, the instantaneous value of the spray burning coefficient is approximately proportional to the instantaneous mass-averaged cylinder gas temperature to the one-third power.

An Experimental Investigation of Flow Fields Within Miniature Scale Centrifugal Pumps

2006 ◽  
Author(s):  
D. Kearney ◽  
J. Punch ◽  
R. Grimes
Keyword(s):  
Centrifugal Pump ◽  
Characteristic Curve ◽  
Flow Fields ◽  
Velocity Profiles ◽  
Heat Fluxes ◽  
Model Verification ◽  
Air Cooling ◽  
Centrifugal Pumps ◽  
Test Bed ◽  
Forced Air

Thermal management has become a key point in the development of contemporary electronics systems. It is evident that heat fluxes are currently approaching the limits of conventional forced air cooling, and that liquid technologies are now under consideration. The objective of this paper is to investigate the flow fields within a miniature scale centrifugal pump in order to determine velocity profiles describing the flow. The experimental setup consisted of a hydrodynamic test bed constructed to measure the pressure-flow characteristic of a centrifugal pump with a rated volumetric flow of 9 l/min. The impeller diameter of the pump under consideration was 34.3mm, and the characterisation experiments were carried out at a constant impeller speed. Particle-Image Velocimetry (PIV) was used to measure velocity profiles within the volute section of the pump. Synchronised velocity profiles are illustrated for three operating points on the pump characteristic curve. A hydrodynamic analysis of the velocity vectors at the impeller tip is also included, and pump model verification is then discussed based on the comparison between the theoretical predictions and the PIV data.

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