Browse Topic: Cooling

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Manufacturing of Transmission Quill Gear by Sinter Hardening2019-26-016501/09/2019
Transmission quill gears are hot forged steel parts often used in constant mesh manual transmissions. The quill gear, which helps to transmit the power from input drive shaft to output shaft through driving gears. It’s having external teeth which is positively engaged with driving gear and sleeve. During gear selection sleeve take load from input shaft and transmit to driven gear. Quill gear directly engaged with driving gears on outer surface and bearing in inner surface which needs to have high strength and durability. These properties can be improved by carburization heat treatment in existing design such processes can lead to increased costs. We have developed quill gear through powder metallurgical process and then cooled rapidly in the furnace to get high strength and wear properties. Material composition are optimized to suit for sinter hardening process conditions. Thus, we have succeeded in the development of quill gears via sinter hardening, thus eliminating the forging and
Gunalan, Magendran, Deshmukh, Rahul, Bane, Uttam
Compression Molding PressTBMG-3336312/01/2018
Beckwood Press Company Fenton, MO 636-343-4100
Thermodynamic Analysis of an Evaporative Inlet Air Cooled Combined Cycle for Marine Application2018-01-177709/10/2018
The integration of inlet air cooling to gas turbine based power utilities is a well accepted practice as this modification to the utility delivers superior utility performance. However, application of inlet-air cooling to drive turbines and specifically to marine mobility sector is rare in literature. Marine vessels are generally propelled by diesel engines, however large marine vessels specifically cruise ships and high speed naval vessels may have requirements of higher speeds and on-board power requirements which can fulfilled by gas turbine driving the propellers while on-board power needs can be met by steam turbine power generated from gas turbine exhaust heat. Such gas-steam combined cycles have the potential to become popular for high capacity marine vessels. The choice of gas turbine based combined cycle power plant for marine vessels in comparison to diesel engine powered vessel is also superior due to lower emission from the former. Higher ambient temperatures are known to
Mohapatra, Alok Kumar, S, Sanjay, Choudhary, Tushar, Kumari, Anupam, S, IRSHAD
HVAC System Bench Test Analysis for TXV Tuning2018-01-007004/03/2018
In today’s automotive industry, the A/C (Air-conditioning) system is emerging into a high level of technological growth to provide quick cooling, warm up and maintaining the air quality of the cabin during all-weather conditions. In HVAC system, TXV plays vital role by separating high side to low side of vapor compression refrigeration system. It also regulates the amount of refrigerant flow to the evaporator based on A/C system load. The HVAC system bench laboratory conducts the test at different system load conditions to evaluate the outputs from tests during initial development stage to select the right TXV in terms of capacity and Superheat set point for a given system. This process is critical in HVAC developmental activity, since mule cars will be equipped with selected TXV for initial assessment of the system performance. The TXV tuning is conducted in system bench lab using defined test load cases which is developed using combination of given input boundary conditions and tests
Sambandan, Saravanan, Valencia, Manuel, Khawaja, Aamir, S, Sathish Kumar
Optimization of the Engine Intake Air Temperature through the Air Conditioning Unit2018-01-097304/03/2018
In modern turbocharged internal combustion engines the cooling of the air after the compression stage is the standard technique to reduce temperature of the engine intake air aimed at improving cylinder filling (volumetric efficiency) and, therefore, overall global efficiency. At present, standard values for the intake air temperature are in the range 30-70°C, dependently on engine load, external air conditions and vehicle speed and the adoption of a dedicated cooling fluid operating at low temperatures (-10-0°C) is addressed as the most viable option to achieve an effective temperature reduction. This paper investigates a pilot engine set-up, featuring an evaporator on the intake line of a turbocharged diesel engine, tested on a high speed dynamometer bench: the evaporator was a part of an air refrigeration unit – the same used for cabin cooling - composed also by a compressor, a condenser and a thermostatic expansion valve. The effects of the undercooling of the charge air have been
Di Battista, Davide, Vittorini, Diego, Di Bartolomeo, Marco, Cipollone, Roberto
Magnetic Cooling of Nanoelectronic ChipsTBMG-2856403/01/2018
High-tech refrigerators have been used to reach temperatures as close to absolute zero as possible — 0 kelvin or -273.15 °C. Physicists aim to cool equipment to as close to absolute zero as possible, because these extremely low temperatures offer the ideal conditions for quantum experiments, and allow entirely new physical phenomena to be examined.
Tech Briefs April 201818AERP0202/01/2018
Multi-Domain Command and Control (MDC2) Changing the Face of Modern Warfare Loop Thermosyphons Gravity-Driven Two-Phase Cooling for the 21st Century CompactPCI Serial Space A New Embedded System Specification Takes on Extreme Environments Plain Bearings for Aerospace Applications Additive Manufacturing Materials for RF Components NASA CubeSats: Pushing the Boundaries of Technology Content Addressable Memory (CAM) Technologies for Big Data and Intelligent Electronics Enabled By Magneto-Electric Ternary CAM New associative memory approach based on the propagation of spikes provides ultra-low energy search operations. Natural DNA-Based Nonvolatile Resistive Switching Memory Reliable memory devices can be realized within a single macromolecule based on natural DNA. A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures Study could lead to more efficient electrically switchable resistive random access memory
AVIONICS REFRIGERATION COOLING SYSTEMARINC728 (Current)10/27/2017
This standard provides standards for the in accordance with which aircraft operators and manufacturers can order avionics refrigeration units and can design installations for an ARCS.
Airlines Electronic Engineering Committee
Improved Modeling of Near-Wall Heat Transport for Cooling of Electric and Hybrid Powertrain Components by High Prandtl Number Flow2017-01-062103/28/2017
Reynolds-averaged Navier-Stokes (RANS) computations of heat transfer involving wall bounded flows at elevated Prandtl numbers typically suffer from a lack of accuracy and/or increased mesh dependency. This can be often attributed to an improper near-wall turbulence modeling and the deficiency of the wall heat transfer models (based on the so called P-functions) that do not properly account for the variation of the turbulent Prandtl number in the wall proximity (y+< 5). As the conductive sub-layer gets significantly thinner than the viscous velocity sub-layer (for Pr >1), treatment of the thermal buffer layer gains importance as well. Various hybrid strategies utilize blending functions dependent on the molecular Prandtl number, which do not necessarily provide a smooth transition from the viscous/conductive sub-layer to the logarithmic region. This work relies on the k-ζ-f turbulence model and the underlying hybrid wall treatment, which is capable of predicting the near-wall momentum
Saric, Sanjin, Ennemoser, Andreas, Basara, Branislav, Petutschnig, Heinz, Irrenfried, Christoph, Steiner, Helfried, Brenn, Günter
Thermal Management of Power Batteries for Electric Vehicles Using Phase Change Materials: A Review2016-01-120404/05/2016
As one of the most crucial components in electric vehicles, power batteries generate abundant heat during charging and discharging processes. Thermal management system (TMS), which is designed to keep the battery cells within an optimum temperature range and to maintain an even temperature distribution from cell to cell, is vital for the high efficiency, long calendar life and reliable safety of these power batteries. With the desirable features of low system complexity, light weight, high energy efficiency and good battery thermal uniformity, thermal management using composite phase change materials (PCMs) has drawn great attention in the past fifteen years. In the hope of supplying helpful guidelines for the design of the PCM-based TMSs, this work begins with the summarization of the most commonly applied heat transfer enhancement methods (i.e., the use of thermally conductive particles, metal fin, expanded graphite matrix and metal foam) for PCMs by different researchers. Newly
Pan, Dongchang, Xu, Sichuan, Lin, Chunjing, Chang, Guofeng
Wavelet-based Fouling Diagnosis of the Heat Exchanger in the Aircraft Environmental Control System2015-01-258209/15/2015
The Environmental Control System (ECS) of an aircraft provides thermal and pressure control of the engine bleed air for comfort of the crew members and passengers onboard. For safe and reliable operation of the ECS under complex operating environments, it is critical to detect and diagnose performance degradations in the system during early phases of fault evolution. One of the critical components of the ECS is the heat exchanger, which ensures proper cooling of the engine bleed air. This paper presents a wavelet-based fouling diagnosis approach for the heat exchanger. The approach is composed of three main steps: i) Feature extraction from the sensor data, where the data is preprocessed using wavelets for improving the information content of the features for fouling classification, ii) Pattern classification, where a classification algorithm is trained from the faulty and nominal datasets, and iii) Classifier evaluation, where the trained classifier is evaluated to determine the
Silva, Andre, Najjar, Nayeff, Gupta, Shalabh, D'Orlando, Paul, Walthall, Rhonda
Femtosecond Laser Processing of Metal and PlasticsTBMG-2219706/01/2015
While precise and fast, the down side to cutting with microsecond (ms) fiber lasers has been that the parts require a number of post-processing operations after they are cut, which add significantly to part cost, and can also damage mechanically delicate parts.
The Thermal and Aerodynamic Development of a Cooling and Heat Resistance Package for a New Hybrid Sports Car2015-01-152604/14/2015
A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept. The experimental and computational developments of ten air cooled-heat exchangers are described with the tradeoffs that were required during the
Onishi, Yasuyuki, Ramsay, Thomas, Juan, Timothy, McKillen, James
Numerical Analysis of Cooling Effects of a Cylinders in Aircraft SI Engine2014-01-288310/13/2014
This paper focuses on the issues concerning gyroplane powertrain cooling. The Rotax 912S engine was selected as a propulsion system following a detailed analysis. A one-dimensional model, simulated with the AVL Boost software, was applied to determine the heat balance of the engine and the heat flux penetrating through each of engine's surfaces. The geometrical quantities defined in the model were obtained by measuring a three-dimensional geometry provided by an authorized Rotax engine supplier company. Calculation results were then verified by comparing the obtained values with data available from the Rotax 912S engine and with the values of individual parameters given in the literature. The CFD simulation studies, performed with Ansys Fluent, enabled to determine the required airflow capable of absorbing up to 6 kW of heat, the properties for sufficient cooling of the cylinders in the gyroplane powertrain system and the manner of directing the air flow in order to achieve the
Grabowski, Lukasz, Czyz, Zbigniew, Kruszczynski, Krzysztof
A Heat Pipe Assisted Air-Cooled Rotary Wankel Engine for Improved Durability, Power and Efficiency2014-01-216009/16/2014
In this paper, we address the thermal management issues which limit the lifespan, specific power and overall efficiency of an air-cooled rotary Wankel engine used in Unmanned Air Vehicles (UAVs). Our goal is to eliminate the hot spots and reduce the temperature gradients in the engine housing and side plates by aggressive heat spreading using heat pipes. We demonstrate by simulation that, for a specific power requirement, with heat spreading and more effective heat dissipation, thermal stress and distortion can be significantly reduced, even with air cooling. The maximum temperature drop was substantial, from 231°C to 129°C. The temperature difference (measure of temperature uniformity) decreased by 8.8 times (from 159°C to 18°C) for a typical UAV engine. Our heat spreaders would not change the frontal area of the engine and should have a negligible impact on the installed weight of the propulsion assembly. We expect our approach could lead to a very significant reduction in thermal
Wu, Wei, Lin, Yeong-Ren, Chow, Louis
Model-Based Thermal Management Functions for Aircraft Systems2014-01-220309/16/2014
This paper describes a novel Thermal Management Function (TMF) and its design process developed in the framework of the Clean Sky project. This TMF is capable of calculating optimized control signals in real-time for thermal management systems by using model-based system knowledge. This can be either a physical model of the system or a data record generated from this model. The TMF provides control signals to the air and vapor cycle which are possible sources of cooling power, as well as load reduction or shedding signals. To determine an optimal cooling split between air cycle, vapor cycle, and its associated ram air channels, trade factors are being used to make electrical power offtake and ram air usage (i.e. drag) comparable, since both have influence on fuel consumption. An associated development process is being elaborated that enables a fast adaptation of the TMF to new architectures and systems. This will be illustrated by means of a bleedless thermal management architecture
Schlabe, Daniel, Lienig, Jens
Stress Relief of Steel PartsAMS2759/11 (Historical)04/23/2014
This specification, in conjunction with the general requirements for steel heat treatment in AMS 2759, establishes requirements for thermal stress relief treatments of parts manufactured from the following materials: a Carbon and Low Alloy Steels b Tool Steels c Precipitation Hardening, Corrosion-Resistant and Maraging Steels d Austenitic Corrosion-Resistant Steels e Martensitic Corrosion-Resistant Steels
AMS E Carbon and Low Alloy Steels Committee
Integrated Low Temperature Cooling System Development in Turbo Charged Vehicle Application2014-01-063804/01/2014
The Low Temperature Cooling (LTC) system is commonly developed for secondary cooling function requirements, such as forced induction air cooling, and HEV power electronics module cooling. The large heat transfer capacity of coolant allows for very compact water-cooled heat exchangers to be installed remotely for better underhood aerodynamic characteristics and more compact packaging design. An integrated LTC loop developed on a Hyundai 2.0L Turbo Charged vehicle extends a traditional WCAC (Water-cooled charged air cooler) application to include a water-cooled condenser (WCOND) module. Unlike other published LTC system design approaches, this research project emphasizes underhood airflow improvement strategy and focuses on heat transfer efficiency. This paper discusses the integrated LTC loop configuration, Low Temperature Radiator (LTR) design, coolant flow control, and others. The LTC system prototype design allowed vehicle performance data to prove that a simplified front end cooling
Song, Xu, Myers, John, Sarnia, Scott
Numerical Simulation of Unsteady Natural Convection in a Simplified Engine Bay Enclosure under Soak Conditions2014-01-065104/01/2014
At the onset of soak, air and surface temperatures in an engine bay enclosure are elevated since temperature of heat sources are high while convective cooling is sharply reduced as a result of airflow being shut off from the inlet grilles of the vehicle leading to temperature spikes. Accurate simulation of this important thermal and flow regime that is natural convection driven, highly transient and complex is therefore very important. In this investigation, we simulate flow in the engine bay at the onset of soak with fixed thermal boundary conditions where the geometries representing the engine bay and components are simplified. Good agreement was observed with detailed experimental data available in references for both velocities and temperatures.
Wang, Zun, Han, Jaehoon, Mukutmoni, Devadatta
Experimental Investigation of Desiccant Wheel Assisted MAC System2014-01-069804/01/2014
In this paper, the application of the separate sensible and latent cooling (SSLC) technology to the mobile air conditioning (MAC) system was investigated. Conventional MAC systems utilize a low evaporating temperature to cool down the cabin air temperature and to remove moisture from humid air. In order to remove the moisture, the supply air temperature has to be below the dew point temperature of the cabin air. Therefore, a reheating process is necessary to increase the air temperature to an appropriate and comfortable level. However, energy is wasted in this reheating process, which results in the reduction of the fuel efficiency. Since the SSLC technology can provide an appropriate solution to these issues of conventional systems, it is proposed to apply the SSLC technology to the MAC system, which can eventually reduce the fuel consumption of the MAC system. In the proposed SSLC MAC system, the desiccant wheel is dedicated to handle most of latent load while the vapor compression
Lin, Xiaojie, Lee, Hoseong, Hwang, Yunho, Radermacher, Reinhard, Kwon, Jungho, Kwon, Chunkyu
CABIN EQUIPMENT INTERFACES PART 7 CABIN EQUIPMENT COOLING GENERAL SPECIFICATIONARINC628P7-2 (Current)06/24/2013
Cabin equipment installations tend to impose loads on aircraft electrical power systems not envisioned in the original airplane design. This standard provides guidance on the design of future aircraft air conditioning and equipment cooling systems. It also describes the environment in which cabin systems, including In-Flight Entertainment equipment are expected to operate.
Airlines Electronic Engineering Committee
CONNECTOR, AIR DUCT HOSE, GROUND COOLING, MALEAS38386/1A (Current)01/07/2013
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
CONNECTOR, AIR DUCT HOSE, GROUND COOLING, FEMALEAS38386/2A (Current)01/07/2013
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Performances and Opportunities of an Engine Cooling System with a Double Circuit at Two Temperature Levels2012-01-063804/16/2012
In the last years, the design of internal combustion engines (ICE) has evolved significantly, mainly because of the changing demand of mobility, the need to limit the pollution produced by vehicles, and recently, the opportunity to reduce emissions of climate-altering gases. Among the more interesting technologies, those connected to a revision of the engine cooling, as well as, in general, of the thermal needs on board vehicle (oil cooling, intercooling of the turbocharging air, EGR cooling, cabin conditioning...) appear very promising, also because characterized by a lower cost increase per unit of CO₂ saved. In this paper, the Authors present a mathematical model of an internal combustion engine physically consistent that appraises the performances of conventional and unconventional engine cooling systems and the integration of vehicle thermal needs. In particular, the Authors studied a double cooling circuit, at two different temperature levels, that allows several improvements in
Cipollone, Roberto, Di Battista, Davide
Safety & Security Category WinnerTBMG-1205811/01/2011
Study of Hybrid Diffusers for Use in Gas Turbine Combustors2011-01-249610/18/2011
Significant development in the gas turbine technology has brought about an increase in the performance requirements for modern engines. This has generated a significant interest in researching into implementation of novel technologies for various engine components, which will allow for the design of engines to match the new performance requirements. One such technology is the use of hybrid diffusers in gas turbine combustors against conventional combustors like dump diffusers. The hybrid diffuser concept has been around for a while and has the potential of giving a greater performance than conventional diffusers. However, due to limited information available in the public domain, not much has been fully understood about the mechanism of the hybrid diffuser concept. Much of the previous work done on hybrid diffusers are done on designs having a vortex chamber bleed, based on the belief that vortex chambers helps to stabilize the flow separation. However, this paper takes looks into the
Khandelwal, Bhupendra, Bao, Liu, Kumar, Karamveer Singh, Sethi, Vishal, Singh, Riti
Cooling Lasers with Thin-Film Thermoelectric CoolersTBMG-1038107/01/2010
Laser diodes for telecommunications have traditionally used thermoelectric coolers (TECs) for precision temperature control to improve diode output levels and maintain wavelength integrity. A major trend for photonics in telecommunications has been the move to more integrated packaging that is smaller and simpler in structure in order to lower costs. This, in turn, has opened the door for higher volume manufacturing. In the course of this transition, conventional TEC solutions have become increasingly difficult to implement as conventional bulk thermoelectric technology has not kept pace with the size and power density requirements for next generation devices.
Liquid Cooling/Warming GarmentTBMG-756503/01/2010
The NASA liquid cooling/ventilating garment (LCVG) currently in use was developed over 40 years ago. With the commencement of a greater number of extra-vehicular activity (EVA) procedures with the construction of the International Space Station, problems of astronaut comfort, as well as the reduction of the consumption of energy, became more salient.
Breathing-Air and Cooling Apparatus for Protective SuitTBMG-TB-00749102/18/2010
Applications can include diving, space, and firefighting suits. The figure schematically illustrates a portable life-support apparatus for any of a variety of protective suits to be worn in hostile environments. A prototype of the apparatus has been fitted to space suits for use underwater. Astronauts wear these suits during training dives in a tank of warm water, using the neutral buoyancy available in the underwater environment to simulate aspects of the zero gravitation of outer space. The apparatus provides breathing air and adjustable cooling in the suit, while maintaining overall neutral buoyancy. The apparatus is readily adaptable to such related applications as conventional diving and space suits, firefighting suits, and protective garments to be worn in hot, toxic, and/or radioactive environments.
Advanced Liquid-Cooling Garment Using Highly Thermally Conductive SheetsTBMG-660401/01/2010
This design of the liquid-cooling garment for NASA spacesuits allows the suit to remove metabolic heat from the human body more effectively, thereby increasing comfort and performance while reducing system mass. The garment is also more flexible, with fewer restrictions on body motion, and more effectively transfers thermal energy from the crewmember’s body to the external cooling unit. This improves the garment’s performance in terms of the maximum environment temperature in which it can keep a crewmember comfortable.
Self-Configuring Hybrid Duct System and Attachment Technologies for Environmental Control Systems2009-01-327711/10/2009
Environmental Control Systems (ECS) ducts on airplanes are primarily fabricated from aluminum or thermoset composites, depending on temperature and pressure requirements. It is imperative to fabricate lightweight, cost effective, durable, and repairable systems with minimal tooling. It is also important that the duct systems are easy to assemble even with alignment issues resulting from structural variations, tolerance accumulation, variation from thermal expansion of different materials, and inherent duct stiffness. These requirements create an opportunity and need for a technology that can address all of these issues, while increasing performance at the same time. This report provides a background on current ECS ducting systems. It also introduces a new, innovative duct system technology and self-torquing attachment system for use in high temperature and pressure systems with the following characteristics: less than half the weight of current systems it is replacing, cost effective
Patel, Jayant D., Amorim, Vitor M.
Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical PowerTBMG-554908/01/2009
Several attractive features of thermo-electric (TE) technology include no moving parts, light weight, modularity, covertness, silence, high power density, low amortized cost, and long service life with no required maintenance. Many of the potential uses for mounted/ dismounted power, such as recharging batteries, are therefore ideal for TE technologies. However, these applications will require more interconnected, smaller-scale modular devices than are currently available. Most commercial off-the-shelf (COTS) TE devices are optimized for cooling, not for generating power, so new device structures with materials and geometries better optimized for power generation are needed for broader use of TE technologies.
Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer SystemsTBMG-505504/01/2009
In a substantial improvement over present alkaline systems, an advanced hybrid bipolar plate for a unitized fuel cell/ electrolyzer has been developed. This design, which operates on pure feed streams (H2/O2 and water, respectively) consists of a porous metallic foil filled with a polymer that has very high water transport properties. Combined with a second metallic plate, the pore-filled metallic plates form a bipolar plate with an empty cavity in the center.
Water Mist System for Shipboard Machinery Space FiresTBMG-TB-00508103/30/2009
The water mist system provides an efficient, effective, and non-toxic means to extinguish ship fires. Water mist has been determined to be a preferred alternative to Halon 1301 total flooding to extinguish fires occurring in ship machinery spaces and pump rooms, because it is toxicologically and physiologically inert. Water mist systems produce a drop size distribution with a range of drop sizes under 1000 μm, while the more conventional sprinkler systems produce much coarser particles. The smaller particle sizes have greater cooling efficiencies because evaporation and cooling are controlled by surface area, and the surface area of a large number of small droplets is greater than that of a small number of large droplets of the same total volume.
Computational Simulation of a Water-Cooled Heat PumpTBMG-319209/01/2008
A Fortran-language computer program for simulating the operation of a water-cooled vapor-compression heat pump in any orientation with respect to gravity has been developed by modifying a prior general-purpose heat-pump design code used at Oak Ridge National Laboratory (ORNL). Al - though it is specific to the design of a high-temperature-lift heat pump for the International Space Station, this program could serve as a basis for development of general-purpose computational software for designing and analyzing liquid-cooled heat-pumps. The ORNL program contained models of refrigerant-fluid-to-air heat exchangers; the main modification consisted in replacing those models with models of plate-type heat exchangers utilizing water as both the cooling and the heating source liquid.
Innovations Pertaining to Carbon-Based MaterialsTBMG-457704/01/2007
Some notable innovations in the design and manufacture of carbonbased materials have been made in a continuing program of basic research on carbon- based materials for use in propulsion systems of aircraft and spacecraft. The research has ranged over diverse topics that have included fabrication of carboncarbon composite-material components, protection of carbon against oxidation, microelectromechanical devices, and surface- tension phenomena.
Effect of Temperature on Weld Strength in Chrome Moly Space Frames2006-01-364812/05/2006
Chromium Molybdenum Steel (AISI 4130), commonly referred to as “Chrome Moly”, is one of the most popular materials used in the construction of tubular space frames and chassis components for racing applications. Its high strength, light weight and comparably low material cost make the reasons for its popularity quite obvious. However, there is one problem that is commonly overlooked: maintaining the strength component of Chrome Moly in areas exposed to high levels of heat followed by rapid cooling during welding. This paper seeks to better understand the affects of cooling due to welding on the strength of Chrome Moly tubing.
Wood, Jonathan, Jawad, Badih, Riedel, Chris
Soymilk And Tofu Processing On Mars: Can We Really Stow It?2004-01-252307/19/2004
The Soymilk, Tofu, Okara and Whey (STOW) Processor Prototype was designated for use in a habitat or extended base [Closed Environment Life Support System (CELSS)] where soybeans will be supplied in bulk or grown locally. Project objectives were to evaluate the STOW Processor’s ability to produce quality soymilk and tofu from the soybean cultivar Hoyt. Hoyt, a small standing, high protein cultivar was selected by the NASA Biomass Production System to be grown hydroponically in the Advanced Integration Matrix (AIM) facility for Mars missions. The quality and yield of the soymilk and tofu from Hoyt was compared to soymilk and tofu produced from three high protein cultivars [Vinton 81 (Gold Standard), C1994, and IA 2032LS]. Composition and characterization of each cultivar was determined using raw soybeans and finished products from small scale stove top systems, large scale steam kettle systems, and STOW simulations. The 2002 field grower Hoyt cultivar had less protein in the bean and
Wilson, Lester A., Zehr, Andy, French, Stephen J., Perchonok, Michele
Performance Characteristics of MOSFETs Operating at High Power2000-01-362210/31/2000
This paper demonstrates that the on-resistance of a power MOSFET decreases significantly when the operating temperature decreases. The decrease in on-resistance under cryogenic temperature allows the device to operate at a much higher power and current condition. Also, it is demonstrated that the MOSFET device can be effectively kept at cryogenic temperature by spray cooling with liquid nitrogen. Over 80 W of heat generated can be removed continuously with spray cooling.
Lin, Y. R., Sundaram, K. B., Chow, L. C.
Aspects of Weld Metallurgical Characteristics and Fracture Mechanism in Formability Tests of Non-Vacuum Electron Beam Tailor-Welded AA5754-O temper Aluminum Blanks2000-01-266310/03/2000
This study determines the correlation between microstructure, fracture mechanism and formability of Al tailor-welded blanks (TWBs). It is found that porosity in the welds is detrimental to the formability of non-vacuum electron beam (NVEB) welded AA5754-O temper Al TWBs. It is also found that the degree of influence of the weld characteristics on formability can be minimal in one test condition, but critical in another, depending on the loading condition, strain state (related to blank geometry) and relative position of the weld seam to the major strain during forming. Metallography, microhardness measurement, electron probe chemical analysis and fractography for 1-2 mm NVEB AA5754-O temper of Al TWBs were used to analyze precipitation, porosity, grain structure, microhardness profile and microchemistry profile across the weld of Al TWBs and their fracture mechanisms during forming tests. Formability of the NVEB welded AA5754 Al TWBs has been previously evaluated. In this study
Wang, Hermina, Martin, Pierre, Clarke, Jo Ann, Altshuller, Bernie, Finn, Mark J., Feng, Frank
Development of alloy cast iron for press die2000-05-019406/12/2000
This paper describes the development of alloy cast iron that can be used for the cutting edges of the trimming die of a press die. Usually, a block of tool steel or steel casting is inserted at the cutting edge of the trimming die of a press die. However, we unified the structure part and the cutting-edge part of a press die with alloy cast iron. As it can''t bear as the cutting edge in this state, the cutting edge is processed by flame-hardening. After the flame- hardening, we developed the alloy cast iron so that enough hardness may be obtained by natural air cooling. Thereby, the machining of the installation seat of the cutting edge decreased and the expense of dies has been reduced.
Shinabe, Masahiro, Nakagawa, Norihiko, Kato, Toru, Nakade, Eiji, Ogawa, Jun, Matsumoto, Tomohiro
Reducing Methanol Crossover in CH3OH-Fuel-Cell MembranesTBMG-671201/01/2000
Improved polymer electrolyte membranes for direct methanol fuel cells can be made by impregnating the baseline membrane material with cross-linked polystyrene (a copolymer of styrene and divinylbenzene). The baseline membrane material is a perfluorosulfonic acid-based hydrophilic, proton-conducting ion-exchange polymer sold under the trade name "Nafion". The principal benefit afforded by the impregnation is a reduction in permeability by methanol; this translates to less crossover of methanol in molecular form (denoted "methanol crossover" for short). Methanol crossover is undesired because it wastes fuel and thereby degrades fuel-cell performance.
Making Liquid Air in Small, Economical QuantitiesTBMG-258109/01/1999
A mixing apparatus combines liquid oxygen and liquid nitrogen to make liquid air in small, convenient quantities. Heretofore, equipment used to make liquid air by mixing was incapable of making batches smaller than 600 gallons (2,300 L). The present mixing apparatus produces liquid air on demand in batches as small as 100 liters; a batch of this size is suitable for filling self-contained breathing apparatuses like those worn by firefighters and others working in hostile environments.
CONNECTOR, AIR DUCT HOSE, GROUND COOLING, FEMALEAS38386/2 (Historical)07/01/1999
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
CONNECTOR, AIR DUCT HOSE, GROUND COOLING, MALEAS38386/1 (Historical)07/01/1999
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Micromachined Heat Sinks1999-01-140804/06/1999
A silicon micromachined heat sink is presented. The device uses liquid cooling in microchannels to remove high heat fluxes. Deep reactive ion etching and multiple wafer bonding is employed to fabricate high aspect ratio, enhanced heat transfer surfaces and a flow channel network that enhances cooling efficiency and minimizes the pressure drop across the device. Experimental test results are presented. Tests to date indicate that up to 76.5 W/cm2 may be removed by the heat sink based on a 100°C electronic device temperature.
Bang, Christopher A., Pan, Tao
Metal Flow of a Tailored Blank in Square Cup Deep Drawing98044702/23/1998
The application of tailored blanks to autobody parts has progressed because of its numerous advantages. The forming of tailored blanks has, however, a lot of technical problems. Among the problems, weld-line movement and formability deterioration are the most significant ones in case of deep drawing. The weld-line movement and formability change were examined experimentally as a function of weld-line location in square cup deep drawing. The weld-line movement of tailored blank consists of two sources. One is the geometrical reason, and the other is due to the hardening of weld bead. The formability of tailored blank is inferior to that of an original blank by the existence of hardened weld region. The mode of fracture changes from wall breakage to a fracture adjacent to punch radius when the weld-line was close to the punch corner.
Pak, Suk-Wan, Usuda, Matsuo, Hayashi, Hisashi
Physical Metallurgy Applications and Enhanced Machinability of Microalloyed V-Ti-N Forging Steels98088402/23/1998
Medium-carbon, microalloyed forging steels represent a cost effective replacement of quenched and tempered grades. Their strength properties are derived from precipitation during cooling from the forging temperature. Because of the relatively high carbon content, vanadium is the most suitable addition to achieve precipitation strengthening. The effectiveness of vanadium is enhanced by the presence of nitrogen. For components subjected to impact loading, improvement in toughness is achieved by refining austenitic grains, pinning their boundaries by means of dispersed titanium nitrides. Precipitation strengthened ferrite-pearlite steels exhibit superior machinability compared to that of quenched and tempered alloy steels. As a result, the total machining costs are substantially reduced compared to the costs of machining heat-treated steels. The frequency of tool breakage and tool changes decrease dramatically, virtually eliminating line scrap and unnecessary downtime. Improved
Banerji, S. K., Glodowski, R. J., Korchynsky, M.
Interstitial Free Sheet Steel - Applications and Performance72001802/01/1972
Interstitial free sheet steel containing columbium (niobium) has been used in a variety of difficult deep drawing applications in the automotive and appliance industries. Performance data have shown a significant increase in deep drawability for this steel over drawing quality aluminum-killed steel. Breakage rates in difficult deep drawn parts have been reduced, often dramatically. One or more anneals between draws have been eliminated and better finished parts have been formed. Laboratory research trials have shown that one or more drawing steps of a multistage draw can be eliminated in a complex part.
Elias, J. A., Hook, R. E.
APPLICATIONS OF CURRENT MATERIALS TO HOT AIRFRAME DESIGN59035201/01/1959
Authors discuss the solution of some hot-airframe design problems using currently available materials, properly selected and arranged. Emphasis is placed on designs which do not employ artificial cooling systems, but do exploit radiant cooling and advantageous thermal characteristics of materials. Desired future developments are also discussed.
DUNN, M. B., MUSGROVE, M. D., RITCHIE, O. T.
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