2,881 research outputs found

    Preliminary study of a serial-parallel redundant manipulator

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    The manipulator design discussed here results from the examination of some of the reasons why redundancy is necessary in general purpose manipulation systems. A spherical joint design actuated in-parallel, having the many advantages of parallel actuation, is described. In addition, the benefits of using redundant actuators are discussed and illustrated in the design by the elimination of loci of singularities from the usable workspace with the addition of only one actuator. Finally, what is known by the authors about space robotics requirements is summarized and the relevance of the proposed design matched against these requirements. The design problems outlined here are viewed as much from the mechanical engineering aspect as from concerns arising from the control and the programming of manipulators

    Identifying and promoting effective spiritual leadership through the role of district superintendent in the Northeast Jurisdiction of the United Methodist Church

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    https://place.asburyseminary.edu/ecommonsatsdissertations/1233/thumbnail.jp

    PENGEMBANGAN STRATEGI PERBAIKAN KUALITAS LAYANAN TAMAN HIBURAN DUNIA FANTASI ANCOL

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    As a recreational place, the amusement park provides entertainment to both domestic and foreign visitors. One of well-known amusement parks in Indonesia is Dunia Fantasi Ancol (Dufan) Jakarta. The objective of this study is to analyze the amusement park visitors’ perception in order to assist the development of improvement strategic plans. The refined Kano 's model and Importance Performance Analysis (IPA) method were applied. Based on data obtained from 272 visitors, there are 18 service attributes that affect the performance of Dufan: 8 attributes have excellent performance levels, 5 attributes have surplus performance levels, and 5 attributes should be improved. Finally, based on Blue Ocean Strategy model, nine improvement strategies and also proposed canvas strategy were provided

    Solar thermochemical production of ammonia from water, air and sunlight: Thermodynamic and economic analyses

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    Ammonia is an important input into agriculture and is used widely as base chemical for the chemical industry. It has recently been proposed as a sustainable transportation fuel and convenient one-way hydrogen carrier. Employing typical meteorological data for Palmdale, CA, solar energy is considered here as an inexpensive and renewable energy alternative in the synthesis of NH3 at ambient pressure and without natural gas. Thermodynamic process analysis shows that a molybdenum-based solar thermochemical NH3 production cycle, conducted at or below 1500 K, combined with solar thermochemical H2 production from water may operate at a net-efficiency ranging from 23 to 30% (lower heating value of NH3 relative to the total energy input). Net present value optimization indicates ecologically and economically sustainable NH3 synthesis at above about 160 tons NH3 per day, dependent primarily on heliostat costs (varied between 90 and 164 dollars/m2), NH3 yields (ranging from 13.9 mol% to stoichiometric conversion of fixed and reduced nitrogen to NH3), and the NH3 sales price. Economically feasible production at an optimum plant capacity near 900 tons NH3 per day is shown at relative conservative technical assumptions and at a reasonable NH3 sales price of about 534 ± 28 dollars per ton NH3

    Methane and Protein from Beef Cattle Manure

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    Dwindling supplies of conventional fossil fuels have prompted renewed interest in recovering energy through the bioconversion of waste organic materials. The large quantities of manure produced in confinement feedlots and the need to manage this manure effectively make feedlots a logical choice for assessing the feasibility of recovering methane and protein through anaerobic fermentation. Research at U.S. Meat Animal Research Center is designed to determine the technical and economic feasibility of recovering methane and protein from beef cattle manure. Specific Objectives are to: 1. Develop design criteria for optimum production of methane and protein through anaerobic fermentation of beef cattle manure, 2. Develop efficient methods to recover high protein biomass from the fermented residue, 3. Evaluate the nutritional value of the biomass as a livestock feed, 4. Determine the capital and operational costs and energy, man-power, and safety requirements for methane fermentation systems associated with livestock operations. This project was initiated in 1976 and is jointly funded by the U.S. Department of Agriculture, Agricultural Research Service, and the U.S. Department of Energy through the Solar Energy Research Institute

    Bio-butanol vs. bio-ethanol: A technical and economic assessment for corn and switchgrass fermented by yeast or Clostridium acetobutylicum

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    Fermentation-derived butanol is a possible alternative to ethanol as a fungible biomass-based liquid transportation fuel. We compare the fermentation-based production of n-butanol vs. ethanol from corn or switchgrass through the liquid fuel yield in terms of the lower heating value (LHV). Industrial scale data on fermentation to n-butanol (ABE fermentation) or ethanol (yeast) establishes a baseline at this time, and puts recent advances in fermentation to butanol in perspective. A dynamic simulation demonstrates the technical, economic and policy implications. The energy yield of n-butanol is about half that of ethanol from corn or switchgrass using current ABE technology. This is a serious disadvantage for n-butanol since feedstock costs are a significant portion of the fuel price. Low yield increases n-butanol's life-cycle greenhouse gas emission for the same amount of LHV compared to ethanol. A given fermenter volume can produce only about one quarter of the LHV as n-butanol per unit time compared to ethanol. This increases capital costs. The sometimes touted advantage of n-butanol being more compatible with existing pipelines is, according to our techno-economic simulations insufficient to alter the conclusion because of the capital costs to connect plants via pipeline
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