Aeronautical Engineering: A special bibliography with indexes, supplement 67, February 1976

This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1976

Development of an optimal manufacturing strategy for low-volume specialty vehicles

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2002.Includes bibliographical references (p. 83-84).by Asoka Veeravagu.S.M.M.B.A

Aeronautical Engineering: A special bibliography with indexes, supplement 62

This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975

Developing Statistical Models to Assess Productivity in the Automotive Manufacturing Sector

The purpose of this study is to identify the most important activity in a value chain, effective factors, their impact, and to find estimation models of the most well-known productivity measurement, Hours per Vehicle (HPV), in the automotive industry in North American manufacturing plants. HPV is a widely recognized production performance indicator that is used by a significant percentage of worldwide automakers. During a comprehensive literature review, 13 important factors that affect HPV were defined as launching a new vehicle, ownership, car segment, model types, year, annual available working days, vehicle variety, flexibility, annual production volume, car assembly and capacity (CAC) utilization, outsourcing, platform strategy, and hourly employee\u27s percentage.;Data used in this study was from North American plants that participated in the Harbour\u27s survey from 1999 to 2007. Data are synthesized using a uniform methodology from information supplied by the plants and supplemented with plant visits by Harbour Consulting auditors. Overall, there are 682 manufacturing plants in the statistical sample from 10 different multinational automakers.;Several robust and advanced statistical methods were used to analyze the data and derive the best possible HPV regression equations. The final statistical models were validated through exhaustive cross-validation procedures. Mixed integer distributed ant colony optimization (MIDACO) algorithm, a nonlinear programming algorithm, that can robustly solve problems with critical function properties like high non-convexity, non-differentiability, flat spots, and even stochastic noise was used to achieve HPV target value.;During the study period, the HPV was reduced 48 minutes on the average each year. Annual production volume, flexible manufacturing, outsourcing, and platform strategy improve HPV. However, vehicle variety, model types, available annual working days, CAC, percentage of the hourly employees, and launching a new model penalize HPV. Japanese plants are the benchmark regarding the HPV followed by joint ventures and Americans. On average, the HPV is lower for Japanese and joint ventures in comparison to American automakers by about 1.83 and 1.28 hours, respectively. Launching a new model and adding a new variety in body styles or chassis configurations raises the HPV, depending on the car class; however, manufacturing plants compensate for this issue by using platform sharing and flexible manufacturing strategies. While launching a new vehicle common platform sharing, flexible manufacturing, and more salaried employees (lower hourly) strategies will help carmakers to overcome the effect of launching new vehicles productivity penalization to some extent.;The research investigates current strategies that help automakers to enhance their production performance and reduce their productivity gap. The HPV regression equations that are developed in this research may be used effectively to help carmakers to set guidelines to improve their productivity with respect to internal and external constraints, strengths, weaknesses, opportunities, and threats

Decision Support System for Inventory Control of Raw Material

PT Suwarni Agro Mandiri Plant Pariaman is a company which produces fertilizer. This company has a problem related to raw material inventory. The inventory can be overstock or stock out. It is due to their working which is not guided by an information system. Therefore, this research proposes a decision support system for controlling the inventory of the raw material. The system uses Material Requirement Planning (MRP) approach and is designed in three sub-systems. They are OLTP database for managing the daily activities, MRP for determining the lot size and the raw material ordering time, and OLAP with data warehouse for analyzing the raw material data. Keywords-inventory; inventory control; online analytical processing; online transaction processin

The use of a Digital Image Correlation method with a low-speed camera to obtain characteristics of surface velocity and sound radiation for automotive-type panels

The perceived quality of a vehicle is highly influenced by the driver s experience of the vehicle interior noise. Significant research has been carried out all over the world in order to characterize structural and acoustic characteristics, to control and minimize the vibration and noise from entering or emitted to vehicles. Designers require tools to inform them whether the design changes are positive or negative in terms of the noise and vibration, and to help validate numerical finite element models of complicated structures. This research explores the use of Digital Image Correlation (DIC) equipment and methods by using a relatively inexpensive low speed camera to investigate the structural-acoustics characteristics applied to automotive-type panels, where otherwise a highly expensive and sensitive scanning laser Doppler vibrometer would be required. Experimental measurements based on Noise Path Analysis (NPA) have been carried out and theoretical and numerical predictions on sound radiation behaviour have been developed. The prediction values have been evaluated and validated with experimental measurements. Using a DIC measurement method to obtain spatially averaged surface velocities, averaged over several cycles through phase locking, the results for the sound power predictions for the selected mode shape and the resonance frequencies provided a good estimation when comparing with the experiment. For mode (1, 1), the sound power prediction was 80.9 dB while the measured one was 77.2 dB with a difference of 3.7.while the other selected modes showed a difference not more than 3.7 dB. It was within the range suggested by considering the mathematical simplification approach during the prediction development stage. To conclude, it was found that the prediction of sound power throughout the vibrating structure can provide a good accuracy by using the DIC method Therefore, it can be an alternative technique to evaluate the sound radiation for characterizing one of the structural propertie

Industry/University Collaboration at the University of Michigan-Dearborn: A Focus on Relevant Technology

https://deepblue.lib.umich.edu/bitstream/2027.42/154105/1/kampfner1997.pd

INJECTION MOLDING OF FLAX FIBER BIOCOMPOSITES BY SIMULATION AND OPTIMIZATION

Flax (Linum usitatissimum) fibers have the advantages of low density, low cost, and recyclability and are considered as a potential material to reinforce plastic materials. Though Canada is one of the largest seed flax growing countries in the world, the utilization of flax fibers as reinforcement in composites is not as developed as in Europe. Indeed, in Canada, a large amount of flax straws are left in the fields and burned by farmers each year. Therefore, development of technologies to make use of flax straws for reinforcement in composites and for other purposes has huge benefits to both the material industries and flax farmers in Canada. This thesis presented a study of flax fibers reinforced biocomposites by injection molding through modeling and optimization. The focus of the study was to understand the relationships between the properties of biocomposites and the processing conditions through the experiment and improve the qualities of biocomposites by optimizing the processing conditions. In this thesis, biocomposites were successfully produced by injection molding with a proposed processing scheme. The influence of flax fiber loading and processing conditions, including injection temperature and pressure on the mechanical properties (tensile properties and flexural properties), and water absorption of biocomposites was investigated. The study also experimentally investigated the effect of the processing conditions (fiber content and temperature) on the rheological properties of biocomposites. In order to implement the simulation analysis of injection molding for biocomposites, the Cross-WLF model was employed to obtain the rheological information of biocomposites. Further, a systematic approach on simulation analysis and optimization of injection molding was proposed to minimize the shrinkage and warpage of biocomposites. Several conclusions are drawn from this study: 1) With respect of the influence of the processing conditions on the properties of biocomposites, (a) Fiber content is the most significant impact factor influencing the mechanical properties of biocomposites compared with the other two processing conditions and the tensile properties and flexural properties of biocomposites dreamingly increased with flax fiber content; (b) lower injection temperature led to higher tensile properties and flexural properties; (c) Water absorption of biocomposites was significantly dependent on fiber content and injection temperature; (d) Injection pressure had no significant effect on either mechanical properties or water absorption. 2) In the study on the rheological characteristics, (a) The shear viscosity of biocomposites increased with fiber content, but at very high shear rates (from 5,000 to 10,000 S−1), the shear viscosities of biocomposites with various fiber content (from 0 to 30%) tended to be the same; (b) The shear viscosity of biocomposites decreased with temperature, and at higher shear rate, all the shear viscosity variations as function of shear rates followed the same rate for different temperatures; (c) At high shear rate, the shear viscosity mostly depended on the shear rate rather than fiber content and temperature; (d) A method was presented to determine the seven parameters of the Cross-WLF model for biocomposites. 3) For minimizing the shrinkage and warpage of injection molded biocomposites, (a) The significant factors on the shrinkage and warpage of biocomposites by injection molding were injection temperature, packing time, and packing pressure; (b) The optimization of the injection molding of biocomposites for reducing the shrinkage and warpage of biocomposites was successful by integrating design of experiment (DOE) and simulation technique. The contribution of this thesis includes: 1) In the field of biocomposites reinforcement, the study has shown a great promise to use flax fibers to enhance the mechanical properties of thermoplastics, in particular an increase of 41.83% in tensile strength and an increase of 47.13% in flexural strength. In addition, this work has provided a mathematical relationship between the processing condition of injection molding and the mechanical properties of biocomposites, which would be important to control the manufacturing process to reach desired mechanical properties. 2) In the field of optimal design and manufacturing of flax fiber biocomposites, this work has provided: (a) an effective method to determine the parameters in the rheology model of the biocomposites melt, which has been an important step in simulating the process, and this method has a generalized implication to other types of biocomposites; and (b) a systematic approach to optimize the injection molding process for minimizing the shrinkage and warpage of biocomposites, which are the two most important quality issues in biocomposites

Aeronautical engineerng: A special bibliography with indexes, supplement 36

This special bibliography lists 628 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1973

Direct solar air heating in linear concentrating collectors assisted by a turbocharger for industrial processes: theoretical analysis and experimental characterization

Mención Internacional en el título de doctorEnergy demand of industry has a relevant share of global energy consumption. The larger portion of industrial demand is heating, mainly provided from fossil fuels. The concerns about pollutant and greenhouse gas emissions, together with the fossil fuels scarcity encourage the research efforts toward environmentally sustainable energy sources and among them, solar energy is widely available. Among solar thermal technologies, linear concentrating collectors represent a suitable solution for providing industrial process heat in the medium temperature range. A heat transfer fluid, as thermal oil, or water, is generally adopted to evacuate heat from the solar receivers and to deliver it to thermal processes, contributing to complexity, cost, and even environmental impact. In this thesis the direct air heating inside concentrating solar collector is investigated as a promising solution for industrial processes requiring hot air in the medium temperature range, aiming at low installation and maintenance costs. Although uncommon, the theoretical analysis carried out revealed the feasibility of direct air heating at atmospheric pressure either in a parabolic trough and linear Fresnel collectors within a limited range of design and operating conditions. The high pumping power required to blow air through the receivers arises as one of the main constraints, becoming unsustainable at medium and large scale. To overcome this limitation, an innovative layout is proposed using an automotive turbocharger to configure an original open-to-atmosphere solar Brayton cycle with null power efficiency. The compressor increases the air pressure before solar heating inside the receivers, minimizing the pumping power consumption. The turbine placed at the receiver outlet recovers the compressing and the pumping power, releasing hot air at between 300 °C and 400 °C for its usage in the thermal process. The maximum allowable temperature of evacuated standard receivers, indicated as 600 °C by most of the manufacturers, limits the inlet turbine temperature. No substantial mechanical excess of power at the common turbine and compressor shaft is expected. Instead, turbocharger freewheeling enables to blow air through the solar receivers without auxiliary energy consumption, eventually delivering the hot air with an overpressure for pumping to the user. To support the proposal, a first small-scale experimental prototype of the turbo-assisted solar air heater is designed and installed, using Linear Fresnel collectors and a low-capacity turbocharger. The experimental results allow the thermal and mechanical characterization of the solar collector and the turbocharger, besides tuning and validating the numerical model implemented. They corroborate the practical viability of the concept and indicates relevant features and critical aspects for scaling up to industrial size. A detailed quasi-steady numerical model is developed, including technical features of commercial linear Fresnel collectors and off-the-shelf turbochargers. Daily and yearly assessments of several medium-scale facilities are obtained considering the typical meteorological year of the selected location. The results allow identifying the relevant design and operating parameters and their effect on the performances of the turbo-assisted solar air heater. By combining theoretical and experimental approaches this thesis establishes the framework for the development, design, optimization, and operation of the innovative technology proposed, opening the possibility to its application to several industrial sectors.La demanda energética de la industria tiene una participación relevante en el consumo energético mundial. La mayor parte de la demanda industrial es calor, principalmente obtenido a partir de combustibles fósiles. Las preocupaciones sobre las emisiones de gases contaminantes y de efecto invernadero, junto con la escasez de combustibles fósiles, fomentan los esfuerzos de investigación hacia fuentes de energía ambientalmente sostenibles, entre las cuales, la energía solar se encuentra ampliamente disponible. Entre las tecnologías solares térmicas, los colectores de concentración lineal representan una solución adecuada para proporcionar calor de proceso industrial en el rango de media temperatura. Generalmente se adopta un fluido caloportador, como aceite térmico o agua, para evacuar el calor de los receptores solares y entregarlo al proceso térmico, contribuyendo a la complejidad, costo, e incluso impacto ambiental. En esta tesis se investiga el calentamiento directo de aire en colectores solares de concentración como una solución prometedora para procesos industriales que requieran aire caliente en el rango de media temperatura, con el objetivo de reducir los costos de instalación y mantenimiento. Aunque poco común, el análisis teórico realizado revela la viabilidad del calentamiento directo del aire a presión atmosférica tanto en colectores cilindro-parabólicos como en colectores Fresnel lineales dentro de un rango limitado de condiciones de diseño y operación. La alta potencia de bombeo necesaria para soplar aire a través de los receptores es una de las principales limitaciones, volviéndose insostenible a mediana y gran escala. Para superar esta limitación, se propone un diseño innovador que utiliza un turbocompresor de automóvil para configurar un ciclo Brayton solar abierto a la atmósfera con una eficiencia energética nula. El compresor aumenta la presión del aire antes del calentamiento solar en los receptores, minimizando el consumo de energía de bombeo. La turbina, colocada en la salida del receptor, recupera la potencia de compresión y bombeo, liberando aire caliente entre 300 °C y 400 °C para su uso en el proceso térmico. La temperatura máxima permitida de los receptores estándar evacuados, indicada como 600 °C por la mayoría de los fabricantes, limita la temperatura de entrada de la turbina, por lo que no se espera un exceso mecánico de potencia sustancial en la turbina común y el eje del compresor. En cambio, el turbocompresor permite soplar aire a través de los receptores solares sin consumo de energía auxiliar de bombeo. Si existiera un exceso, estará disponible para el bombeo hasta el usuario. Para apoyar la propuesta, se diseña e instala un primer prototipo experimental de pequeña escala del calentador de aire solar turbo-asistido, utilizando colectores lineales Fresnel y un turbocompresor de baja capacidad. Los resultados experimentales permiten la caracterización térmica y mecánica del colector solar y el turbocompresor, además de ajustar y validar los modelos numéricos implementados. Los ensayos corroboran la viabilidad práctica del concepto e indican características relevantes y aspectos críticos para escalar al tamaño industrial. Se desarrolla un modelo numérico cuasi-estacionario detallado, que incluye las características técnicas de los colectores Fresnel lineales comerciales y los turbocompresores estándar. Se obtienen evaluaciones diarias y anuales de varias instalaciones de mediana escala considerando el año meteorológico típico de la ubicación seleccionada. Los resultados permiten identificar los parámetros de diseño y funcionamiento relevantes y su efecto sobre el rendimiento del calentador de aire solar turbo-asistido. Combinando enfoques teóricos y experimentales, esta tesis establece el marco para el desarrollo, diseño y operación de la tecnología innovadora propuesta, abriendo la posibilidad de su aplicación a varios sectores industriales, apuntando a la descarbonización y transición industrial sustentable.This research was supported by the Industrial Ph.D. project “Producción directa de aire a alta temperatura y a presión turboalimentada en colectores solares de concentración” (BOCM Reference IND2017/AMB7769) funded by “Comunidad de Madrid”, Spain (Orden 3779/2017 of October 17th 2017, by “Consejero de Educación e Investigación”, pubblished on “BOCM. 252, of October 23th 2017.)Programa de Doctorado en Ingeniería Mecánica y de Organización Industrial por la Universidad Carlos III de MadridPresidente: Eduardo A. Rincón Mejía.- Secretario: José Miguel Cardemil Iglesias.- Vocal: José González Aguilaré Migue