3,072 research outputs found

    Some Physiological Effects of Non-Gaseous Exhaust Material from an Internal Combustion Engine

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    Author Institution: Department of Chemistry, Ashland College, Ashland, OhioExhaust materials were collected from a four-cylinder automobile engine that consumed 1 quart of lubricating oil for each 5 gal of gasoline. The oily condensate was separated into three fractions. These fractions contained paraffins, olefins, and cycloparaffins as fraction I, aromatics as fraction II, and non-hydrocarbons and oxygenated compounds as fraction III. The solvents produced no noticable effects on test mice after 279 days of testing. Fractions I and II produced ulcerated sores which formed thick scabs. Fraction II also produced a small amount of cancerous cells at the site of application. Fraction III produced thin scabs and was associated with hyperirritability and other evidence of central nervous system changes. This fraction was lethal in doses of 100 mg per week

    Application of advanced technologies to small, short-haul transport aircraft (STAT)

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    The benefits of selected advanced technologies for 19 and 30 passenger, short-haul aircraft were identified. Advanced technologies were investigated in four areas: aerodynamics, propulsion, structures, and ride quality. Configuration sensitivity studies were conducted to show design tradeoffs associated with passenger capacity, cabin comfort level, and design field length

    You Can Simplify Oat-Legume-Grass Seeding

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    An oat-legume-grass mixture can be seeded successfully in one trip over the field with a single-hopper machine. Seed separation isn\u27t a problem, and you can achieve uniform seed distribution and a satisfactory planting depth

    Herbicides for Trefoil Seedings?

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    Birdsfoot trefoil is an important legume in many parts of Iowa for improving permanent pastures. No other pasture legume now available compares with birdsfoot trefoil in its ability to withstand continuous grazing. Once established, stands may be expected to furnish high-quality pasture for many years

    INTRODUCING A NETWORK OF EMERGING COMMERCIAL TECHNOLOGIES TO COMBAT WILDFIRES ON DOD INSTALLATIONS

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    The purpose of this thesis is to analyze the fiscal, environmental, and health impacts of wildfires aboard Marine Corps Base (MCB) Camp Pendleton and the potential benefits of incorporating Project Vesta, a system of emerging commercial-off-the-shelf technologies, into Camp Pendleton’s firefighting capabilities. The main objective of this report is to determine the cost of acquiring Project Vesta and the benefit of fielding it aboard Camp Pendleton and other DOD installations at risk from wildfires. First, we determine the growing threat of wildfires to MCB Camp Pendleton and their fiscal, environmental, and health impacts. Second, we analyze current firefighting detection and suppression methods to determine shortfalls and potential costs derived from insufficient responses. Finally, we identify Project Vesta integration opportunities and conduct a sensitivity analysis of the cost-benefit to better combat wildfires aboard MCB Camp Pendleton. This study determines how investing in Project Vesta will allow fire departments to detect fires sooner and suppress fires faster, leading to reduced costs by protecting people, resources, and training environments. Based on this research, we recommend that DOD facilities that are regularly impacted by wildfires acquire the Vesta system and integrate it into their fire departments.Major, United States Marine CorpsMajor, United States Marine CorpsApproved for public release. Distribution is unlimited

    SURFACE TREATMENT FOR THE MITIGATION OF WHEY PROTEIN FOULING

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    Heat transfer fouling experiments were carried out in a temperature controlled stirred vessel using aqueous solutions of whey protein concentrate in the concentration range of 3 to 3.5 wt-% at a bulk temperature of 50 °C and pH of 6. Heat transfer data were obtained from thermocouples embedded in an immersed electrical heating rod with various metal plates attached with-and-without surface treatments. Measurements included solution temperature, heating element surface temperature, and heat duty. Results are presented as fouling resistance versus time for aluminum, copper, stainless steel, electro-polished stainless steel, and surfaces coated with DLC and doped with Si , SiO, as well as DLC-coating of an electro-polished stainless steel. Reducing surface roughness was found to mitigate fouling but the combination of both surface treatments, DLC coatings, and electro-polishing gave the best performance. The experimental results demonstrate the potential and value for reducing the adhesive behavior of whey protein fouling layers using modified surfaces. Also a comparison of these results with those for crystallization fouling show the same effects of the surface modification on nucleation and crystal growth. Of particular importance is the influence on the cleaning performance where the main potential can be expected

    Quantum theory of impact ionization in coherent high-field semiconductor transport

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    Generation of carriers in semiconductors by impact ionization is studied under the influence of a constant, arbibrarily high electric field. Using the density-matrix approach a system of equations for the coherent dynamics of electrons and holes in the presence of impact ionization and Auger recombination is derived, which extends the semiconductor Bloch equations by the inclusion of impact-ionization density-correlation functions as additional dynamic variables. From these equations we recover the pure (Zener) and the photon-induced (Franz-Keldysh) carrier tunneling rate and derive an expression for the field-assisted impact-ionization scattering rate. Different levels of approximation of the kinetic equations are discussed. It is shown that in contrast to the semiclassical treatment in the presence of an electric field, a fixed impact-ionization threshold does no longer exist, and the impact-ionization scattering rate is drastically enhanced around the semiclassical threshold by the intracollisional field effect. The close connection of field-assisted impact ionization to the Franz-Keldysh effect is emphasized

    INFLUENCE OF DIFFERENT SURFACE MATERIALS ON NUCLEATION AND CRYSTAL GROWTH IN HEAT EXCHANGERS

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    The influence of different materials on the fouling tendency in saline calcium sulfate solution was investigated. The effects of the untreated material on the crystallization process have been studied experimentally in the micro- and macroscopic scale. The crystallization in the induction period was visualized with SEM and AFM to locate preferred nucleation spots and to visualize the crystal growth. The different materials are showing different crystal growth behavior (number and size of the crystals). These results are corresponding with the macroscopic fouling results with limited shear stress. Also different roughness values on stainless steel have been studied with respect to fouling tendency. The induction time can be extended with smoother surfaces due to the limitation of nucleation spots. With higher fluid velocities, the adhesion of the forming crystals on the heat transfer surface dominates the length of the induction time

    EXTENDING THE INDUCTION PERIOD OF CRYSTALLIZATION FOULING THROUGH SURFACE COATING

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    To minimize the negative effects of scale formation in heat exchangers, new anti-fouling strategies are focusing on the modification of heat transfer surfaces. These modifications should lead to tailored made surfaces for different technical applications. Aim of this surface modification is the extension of the induction period to minimize the negative effects of fouling and maximize the endurance of the heat exchanger. To achieve such, different surface coatings on stainless steel were investigated in respect of fouling tendency. The effect of flow velocity respectively Reynolds number on the induction time of CaSO4 crystallization fouling were tested in different test units. Diamond like carbon coatings are extending the induction time in every measured flow velocity. At higher Reynolds numbers, the effect of different surface crystallization due to energetic modification is reduced because of the dominating effect of the low adhesive surface. Thus the induction time can be extended by the factor of 2 for low fluid velocities (DLC or SICON®) and more than 20 for higher Reynolds numbers (DLC and SICON®). The combination of limited nucleation spots due to electro-chemical treatment of the substrate before coating can be a tailored made surface with maximum induction time for crystallization fouling

    Quantum theory of impact ionization in coherent high-field semiconductor transport

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    Generation of carriers in semiconductors by impact ionization is studied under the influence of a constant, arbibrarily high electric field. Using the density-matrix approach a system of equations for the coherent dynamics of electrons and holes in the presence of impact ionization and Auger recombination is derived, which extends the semiconductor Bloch equations by the inclusion of impact-ionization density-correlation functions as additional dynamic variables. From these equations we recover the pure (Zener) and the photon-induced (Franz-Keldysh) carrier tunneling rate and derive an expression for the field-assisted impact-ionization scattering rate. Different levels of approximation of the kinetic equations are discussed. It is shown that in contrast to the semiclassical treatment in the presence of an electric field, a fixed impact-ionization threshold does no longer exist, and the impact-ionization scattering rate is drastically enhanced around the semiclassical threshold by the intracollisional field effect. The close connection of field-assisted impact ionization to the Franz-Keldysh effect is emphasized
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