1,687 research outputs found

    A project and competition to design and build a simple heat exchanger

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    To address a declining interest in process engineering, a project to design and build a compact heat exchanger was initiated in the second year of a four-year, multidisciplinary degree programme in biotechnology. The heat exchangers had a double-pipe configuration and employed plastic outer pipes and copper inner pipes of various diameters. Designs produced ranged from coiled inner pipes to various multi-pass arrangements and were assessed on the basis of heat transfer achieved per unit mean temperature difference per unit cost. The project, which also formed the basis of a competition, was very well received by students and gave them hands-on experience of engineering design and construction, as well as team work, problem solving, engineering drawing and the use of simple tools. Based on the success of this project, a similar problem based learning approach will be initiated in the third year of the same degree programme and will focus on bioethanol production

    Buckling of imperfect cylinders under axial compression

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    Donnell equations, Newton method, and numerical solution applied to buckling of imperfect cylinders under axial compressio

    Lightweight composite reflector panels

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    The Hexel Corp. has produced additional composite panels, based on JPL designs, that: (1) have increased the panel size from 0.15 to 0.40 meters, (2) have improved the as-manufactured surface precision 3.0 to approx. 1.0 micron RMS, (3) have utilized different numbers of face sheet plys, (4) have improved face sheet fiber orientation, (5) have variations of aluminum honeycomb core cell size, (6) have combined graphite/epoxy (Gr/Ep) face sheets with E-glass honeycomb cores, and (7) have used standard aluminum core with face sheets composed of combinations of glass, Kevlar, and carbon fibers. Additionally, JPL has identified candidate alternate materials for the facesheets and core, modified the baseline polymer panel matrix material, and developed new concepts for panel composite cores. Dornier designed and fabricated three 0.6 meter Gr/Ep panels, that were evaluated by JPL. Results of both the Hexel and Dornier panel work were used to characterize the state-of-the-art for Gr/Ep mirrors

    Spray Formation from Spark-Eroded and Laser-Drilled Injectors for DISI Engines with Gasoline and Alcohol Fuels

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    Copyright © 2014 SAE International.One of the latest advancements in injector technology is laser drilling of the nozzle holes. In this context, the spray formation and atomisation characteristics of gasoline, ethanol and 1-butanol were investigated for a 7-hole spark eroded (SE) injector and its ‘direct replacement’ Laser-drilled (LD) injector using optical techniques. In the first step of the optical investigation, high-speed spray imaging was performed in a quiescent injection chamber with global illumination using diffused Laser light. The images were statistically analyzed to obtain spray penetration, spray tip velocity and spray ‘cone’ angles. Furthermore, droplet sizing was undertaken using Phase Doppler Anemometry (PDA). A single spray plume was isolated for this analysis and measurements were obtained across the plume at a fixed distance from the nozzle exit. The droplet measurements were grouped into bins and maps were created showing droplet sizes and velocities against time and position during and post injection. All tests were performed at 120 bar fuel pressure, two injection chamber ‘back’ pressures (0.5 bar and 1 bar) and two injector temperatures (20 °C and 80 °C), to examine effects relevant to typical engine operating conditions with early intake stroke injection strategies, including fuel flash boiling

    The Third Way

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    Liberal education and professional education have traditionally been considered opposites. According to received academic wisdom, students seeking broad exposure to the arts and sciences should not be burdened with acquiring workplace skills, and students preparing for careers in fields such as business and engineering should not be diverted by more than a token engagement with irrelevant liberal arts content

    Numerical analysis of a downsized 2-stroke uniflow engine

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    In order to optimize the 2-stroke uniflow engine performance on vehicle applications, numerical analysis has been introduced, 3D CFD model has been built for the optimization of intake charge organization. The scavenging process was investigated and the intake port design details were improved. Then the output data from 3D CFD calculation were applied to a 1D engine model to process the analysis on engine performance. The boost system optimization of the engine has been carried out also. Furthermore, a vehicle model was also set up to investigate the engine in-vehicle performance

    The Effect of Sex and Background on Doxorubicin-Induced Cardiotoxicity in Carbonyl Reductase 1 +/- Mice: A Comparative Study

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    Doxorubicin has long been used clinically to treat a variety of cancers. Unfortunately, its success is limited due to its cardiotoxic side effects, restricting the cumulative dose that can be given to patients. It is known that the enzyme carbonyl reductase 1 (Cbr1) metabolizes this cancer drug in vivo, leading to the production of its toxic alcohol metabolite, doxorubicinol. A previous study has indicated that decreasing the expression level of carbonyl reductase 1 in male Cbr1+/- mice provided them with significant protection from doxorubicin-induced cardiotoxicity when compared to their wild type littermates. With the intent to identify whether the protection conferred by knocking out one copy of Cbr1 persists in a more diverse population, this subsequent study expanded the previous one to include female mice as well as mice of different genetic backgrounds. It was discovered that the protective effect conferred by a null Cbr1 allele is no longer present, that females significantly longer than males, and that survival is no longer significantly associated with cardiotoxicity. Western blotting, subclinical pathogen analysis, histology, and pedigree analysis were performed in an effort to discover an explanation for the unexpected results. It is believed that alternate acute toxicity such as leukopenia was responsible for mouse death, whereas such factors are controlled in human clinical trials. In the event that decreased Cbr1 levels provide significant cardiac protection, a Cbr1 inhibitor could be created to be taken simultaneously with doxorubicin

    The Political Process as Final Solution

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    Five meter diameter conical furlable antenna

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    An investigation was made to demonstrate that a 5-meter-diameter, furlable, conical reflector antenna utilizing a line source feed can be fabricated utilizing composite materials and to prove that the antenna can function mechanically and electrically as prototype flight hardware. The design, analysis, and testing of the antenna are described. An RF efficiency of 55% at 8.5 GHz and a surface error of 0.64 mm rms were chosen as basic design requirements. Actual test measurements yielded an efficiency of 53% (49.77 dB gain) and a surface error of 0.61 mm rms. Atmospherically induced corrosion of the reflector mesh resulted in the RF performance degradation. An assessment of the antenna as compared to the current state of the art technology was made. This assessment included cost, surface accuracy and RF performance, structural and mechanical characteristics, and possible applications
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