Xem 1-15 trên 15 kết quả Cooling rate
  • Fe73.5Si13.5B9Nb3Au1 ribbons have been prepared by rapid cooling on a single copper wheel with different speeds of wheel of 10, 20, 30, and 40 m/s. The as-spun samples are amorphous. Upon annealing, the nanocrystalline phases are formed. Increasing the cooling rate leads to thinner ribbons, higher crystallization activation energy and crystallization volume fraction of the α-Fe(Si) phase, slightly increasing Curie temperature and soft magnetic properties of annealed ribbons. The large magnetic entropy change is observed for sample with v = 30 m/s.

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  • Critical Cooling Rate at 550 °C (1020 °F) (Tc). A critical cooling rate exists for each steel composition. If the actualcooling rate in the weld metal exceeds this critical value, then hard martensitic structures may develop in the HAZ, and there is a great risk of cracking under the influence of thermal stresses in the presence of hydrogen. The best way to determine the critical cooling rate is to make a series of bead-on-plate weld passes in which all parameters, except the arc travel speed, are held constant. ...

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  • Two major approaches to cryopreservation are known, i.e., conventional freeze-thaw procedures and vitrification, which is defined as a glass-like solidification (Karlsson & Toner, 1996). While freeze-thaw procedures minimize the probability of intracellular ice formation, vitrification attempts to prevent ice formation throughout the entire sample during the cooling and warming process (Kuleshova et al., 2007). Recently, the potential of vitrification has been tested for tissue-engineered constructs.

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  • All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy...

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  • Antifreeze proteins (AFPs) possess a unique ability to bind to a seed ice crystal to inhibit its growth. The strength of this binding has been evalu-ated by thermal hysteresis (TH). In this study, we examined the dependence of TH on experimental parameters, including cooling rate, annealing time, annealing temperature and the size of the seed ice crystal for an isoform of type III AFP from notched-fin eelpout (nfeAFP8).

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  • Source: HANDBOOK OF MECHANICAL ENGINEERING CALCULATIONS SECTION 9 AIR AND GAS COMPRESSORS AND VACUUM SYSTEMS Estimating the Cost of Air Leaks in Compressed-Air Systems 9.1 Selecting an Air Motor for a Known Application 9.4 Air-Compressor Cooling-System Choice for Maximum Coolant Economy 9.10 Economics of Air-Compressor Inlet Location 9.14 Power Input Required by Centrifugal Compressor 9.16 Compressor Selection for CompressedAir Systems 9.18 Sizing Compressed-Air System Components 9.24 Compressed-Air Receiver Size and Pump-Up Time 9.26 Vacuum-System Pump-Down Time 9.

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  • The theoretical analysis and modeling of heat and mass transfer rates produced in evaporation and condensation processes are significant issues in a design of wide range of industrial processes and devices. This book introduces advanced processes and modeling of evaporation, boiling, water vapor condensation, cooling, heat transfer, heat exchanger, fluid dynamic simulations, fluid flow, and gas flow to the international community.

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  • CHAPTER 64 INDOOR ENVIRONMENTAL CONTROL Jerald D. Parker F. C. McQuiston Professors Emeritus Oklahoma State University Stillwater, Oklahoma 64.1 MOIST AIR PROPERTIES AND CONDITIONING PROCESSES 64.1.1 Properties of Moist Air 64.1.2 The Psychrometric Chart 64.1.3 Space Conditioning Processes 64.1.4 Human Comfort SPACEHEATING 64.2.1 Heat Transmission in Structures 64.2.2 Design Conditions 64.2.3 Calculation of Heat Losses 64.2.4 Air Requirements 64.2.5 Fuel Requirements SPACECOOLING 64.3.1 Heat Gain, Cooling Load, and Heat Extraction Rate ...

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  • Earlier automobile engine development produced a much larger range of engines than is in common use today. Engines have ranged from 1- to 16-cylinder designs with corresponding differences in overall size, weight, piston displacement, and cylinder bores. Four cylinders and power ratings from 19 to 120 hp (14 to 90 kW) were followed in a majority of the models. Several three-cylinder, two-stroke-cycle models were built while most engines had straight or in-line cylinders. There were several V-type models and horizontally opposed two- and four-cylinder makes too.

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  • One of the key decisions in achieving successful freezing of tissue-engineered products is the choice of cryoprotectant. Cryoprotectants minimize damage caused by ice crystal formation and should induce an amorphous state, rather than ice crystals during the cooling and warming phases. Although the use of cryoprotectants is mandatory, currently available reagents are cytotoxic to some extent. Since tissue-engineered products are larger than isolated cells, longer incubation times with cryoprotectant are necessary which may result in a lower survival rate.

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  • At very high temperatures and constant heat loads even camels need to dissipate heat. Many mammals achieve evaporative cooling through an increased respiratory rate rather than by sweating. Respiratory cooling is relatively more expensive in water than is sweating since faster respiration rates result in more energy being used. Normal respiratory rates in camels are in the range of 6 to 11 breaths/min. (average 8) in the Sahara. Under heat stress these increase to levels of 8 to 18 (average 16). Such low respiration rates do not result in significantly increased evaporation. ...

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  • Overseas investors bought a net USD19.5 billion of stocks and bonds during 2007, compared with the previous record of USD8.9 billion in 2006. The current year has seen net outflows in the first 9 months totaling USD6.9 billion. The bank rate is currently 6% (July 2008) and longer-term deposit rates have risen around 50 basis points (bp) to 9.55% in recent months. Real estate markets have been buoyant, although they have cooled recently, and the banking system remains sound and well capitalized. In March 2008, the capital adequacy ratio stood at 13.

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  • Many animals respond to a hot environment by resorting to an increased respiration rate and in some cases to open-mouth panting. Respiration rates in the camel increase very little with increase in ambient heat load and the respiratory route, probably, is a very minor source of water loss. In addition, camels are able to exhale unsaturated air under some conditions. The combination of cooling and desaturation can result in saving 60% of the water that would be present in fully saturated air exhaled at body temperature.

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  • This is a simple unipolar stepper board that can control stepper motors rated to 30VDC. The FET drivers are rated at 50A, but in practicality this board should not be used with motors anywhere near that current for several reasons. The power supply voltage, heat sinks and cooling used for the FET’s of your own application play an extremely important part in making that determination. The FET package is designed for 50 Watts of dissipative power. If you’re not wise in electronics, the board should be built in stages and tested during each stage to eliminate problems....

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  • At that time, evolutionary biology was in eclipse. Many scientists thought that Lord Kelvin’s arguments about the rate of the earth’s cooling proved Darwin wrong (Kelvin 1862). Others recognized that Darwin’s theory of transmission by gemmules was inconsistent with his theory of natural selection (Richards 1987). Natural selection was not re-incorporated into biology until its underpinnings in population genetics were developed in the early to middle years of the 20th century (Fisher 1930).

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