Forced Convection Heat Transfer Coefficient and Pressure Drop of Diamond-Shaped Fin-Array

After reading Professor Ali Farazmand's essay "Building Administrative Capacity in the Age of Rapid Globalization: A Modest Prescription for the Twenty-First Century," one is reminded that the list of capacities we need to develop is long, the tasks are diverse, and the challenges are tremendous. By offering a "modest" prescription, Farazmand departs emphatically from recent attempts to rewrite administrative capacity by downgrading it and outsourcing it to the market or by making it imitate corporate structures and techniques. Such exercises of yesteryear are correctly being excoriated now, but it would be well to remember that this failed model was inspired and facilitated by the stagnation and many perversities of the state-centered model that it replaced. As we stand at the cusp of a new generation of public administration reforms, we are reminded by Professor Farazmand's exposition that we no longer have any widely accepted and integrative theories left to guide our practice of reform, and that a search must begin to look at past evidence with a critical eye toward developing practical and theoretical insights to advance the public administration agenda

AJTEC2011-44017 PRECISE CONTROL METHOD OF TEMPERATURE RISING SPEED OF WAFER DURING RAPID THERMAL PROCESSING WITH LAMP HEATERS

ABSTRACT In rapid thermal processing of a semiconductor wafer, temperature-rising-time is the same order of heating-time, and so keeping a given temperature-rising-speed of the wafer during the temperature-rising process is important. We made an experimental apparatus to measure the temperature-rising-speed of a ceramic ball of 2 mm in diameter heated with four halogen lamp heaters. The temperature change of the ceramic ball was measured and the heating rate of the halogen lamp heaters was controlled by a personal computer to keep a given temperature-risingspeed 50°C/s with controlling-time-interval 0.1 s. We examined the effect of various heating control methods on the error of the temperature-rising-speed of the ceramic ball. We tested the PID-control, the control with a prepared correlation, and the combined method of control with prepared correlation and PID-control. We found that the combined method is a good method to decease the error of the temperature-rising-speed. The average error of the temperature-rising-speed is 0.5°C/s and the repetition error is almost zero for the temperature-rising-speed 50°C/s during 330°C to 370°C. We also measured the effects of artificial control-delay-time and measuring-error of the monitor temperature on the error of the temperature-rising-speed

Overview of Deployment of Magnetic Refrigeration in Heat Pump Systems

The majority of cooling systems are based upon vapor-compression refrigeration technology. Its principle has been unchanged for more than a century. Miniaturization and competitiveness have been gained, but there’s still a need of alternative technologies, which can operate with better efficiency, lower energy consumption and better environmental safety. One of the most promising alternatives to a conventional vapor compression system is magnetic refrigeration. In this article, an overview of the current state of development of a room-temperature magnetic heat pump is reported

Study on a pulsating heat pipe with selfrewetting fluid

This paper discusses a pulsating heat pipe (PHP) usin

MNHMT2009-18202 Effect of Self-Rewetting Fluids on Pulsating Heat Pipe Thermal Performance

ABSTRACT Pulsating heat pipes (PHPs) have recently emerged as a possible cooling device for high heat flux electronics to replace conventional cooling devices. In this study, new experimental results were obtained for using self-rewetting fluids to enhance the heat transport of PHPs. Unlike other common liquids, the surface tension of self-rewetting fluids increases with temperature. The increase in surface tension at high temperatures causes the liquid to be drawn towards a heated surface if a dry spot appears, which improves boiling heat transfer. PHPs were constructed out of multiport extruded aluminum tubing with a square channel cross section. In experiments, heptanol was added to water at a concentration of less than 1 wt% to form the self-rewetting fluid. Several other parameters were adjusted for optimization, such as the aqueous alcohol solution concentration of the working fluid, the fluid fill ratio, and the heat pipe orientation. Using a self-rewetting fluid in PHPs was found to be highly effective in improving their heat transport capability. The PHPs delivered a better performance when oriented vertically rather than horizontally. As a working fluid, the heptanol water mixture outperformed both the butanol water mixture and pure water within the parameters of this experiment

Optimisation d'un système magnétique à température ambiante utilisé dans les applications de refroidissement d'air

The purpose of this study is to understand the optimum operating condition of magnetic refrigerator at room temperature for direct air-cooling. The basic components of the target system are a magnetic circuit including two permanent magnets, a test section, an air blower, and an associated instrumentation. The test section consists of 10 test cells which enclose gadolinium chips as a magnetic working substance in a prescribed packing rate. In order to change the applied magnetic field from 0 to 0.9 T, the magnetic circuit is installed on an electric slider which generates reciprocating motion. The system performances are widely investigated both experimentally and analytically for the variety of conditions such as a volumetric flow rate of air, a packing length of magnetic working substance, and a heat exchange cycle. The results reveal that the present magnetic refrigerator has a maximum value of the cooling rate in an appropriate operating condition

Designing Japanese Speech Database Covering Wide Range in Prosody for Hybrid Speech Synthesizer

ICSLP2002: the 7th International Conference on Spoken Language Processing , September 16-20, 2002, Denver, Colorado, USA.For the purpose of building Text-to-Speech (TTS) system that can generate high-quality and wide range speech in prosody, we conducted speech database construction. As a speech synthesizer, we use a hybrid system which consists of a unit selection module and prosody modification by STRAIGHT (vocoder type high quality analysis- synthesis method). Our viewpoint is to reduce an amount of prosody modification which causes quality deterioration. In other words, it is to generate any prosody at will within permissible prosody modification. Based on the aspect, we designed 9 sub-databases those consist of same phonetic balanced texts with different prosody. In this paper, we describe the designing policy and general features of the obtained database and the results of listening tests focused on the effectiveness about durational feature. They shows the advantage of the proposed database. and but it is also observed the necessity to change unit selection cost function according to output speech rate