3,912 research outputs found

    Reusable rocket engine turbopump condition monitoring

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    Significant improvements in engine readiness with attendant reductions in maintenance costs and turnaround times can be achieved with an engine condition monitoring system (CMS). The CMS provides real time health status of critical engine components, without disassembly, through component monitoring with advanced sensor technologies. Three technologies were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiber optic deflectometer (bearings), and the fiber optic pyrometer (blades). Signal processing algorithms were evaluated and ranked for their utility in providing useful component health data to unskilled maintenance personnel. Design modifications to current configuration Space Shuttle Main Engine (SSME) high pressure turbopumps and the MK48-F turbopump were developed to incorporate the sensors

    Fluid structure interaction of submerged metallic and composite plates subjected to low velocity impact loading

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    An instrumented low velocity impact rig has been used to acquire experimental data for impacts in air and underwater for both metallic and composite plates when subjected to a low velocity drop-weight impact with a 2kg steel impactor. Initial impact studies were conducted in air and then repeated for submersed conditions underwater. Experimental results are compared for all tests with numerical solutions and are found to be in good agreement. For underwater impact, the numerical model incorporates the use of a Eulerian formulation for the water with a coupled fluid-structure interaction algorithm. The effect of the water surrounding the target plates was found to reduce the peak accelerations and also reduce the overall impact duration when compared to the same impacts in air. X-Ray imagery of the composite plates also showed visibly reduced damage for the submersed test specimens. This research provides data on the impact response of metallic and composite materials, and validates numerical methodologies for use in future work on fluid-structure interactions which show strong potential for relevant industrial applications

    Ansiotropic mechanical behavior of copper-beryllium alloy strip

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    Tensile and bend test data were compiled for copper-beryllium alloy strip with composition, cold work, thermal treatment and directionality as variables

    Collecting and compiling: The activity of seeking pictures in primary school

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    Purpose: The aim of this study is to further understanding of the situated activity of seeking pictures. It relates to an ongoing discussion on how multimodal information literacies are enacted in different social practices. Design/methodology/approach: In order to understand the characteristics of the communication and interactions in the activity of seeking pictures, video recordings from an ethnographic study of primary school children working with problem-centred assignments have been analysed. Findings: The analysis reveals how the activity of seeking pictures is shaped by the assumption that pictures are different from facts and information; pictures are seen primarily as having decorative functions. The activity is also characterised by playful, yet efficient cooperation between the children; they make the activity meaningful by transforming it into a play and game activity where pictures become important as physical objects, but not as a semiotic means of learning. Research limitations/implications: The study is limited to the activity of seeking pictures in a specific primary school; however, it shows how modes other than textual modes can be included in the study of information activities. Practical implications: The study reveals the need for developing methods for enhancing children's possibilities to critically examine and learn from visual material, such as pictures. Originality/value: Research on information seeking and information literacies rarely focus on multimodal aspects of information activities or the seeking of pictures outside special collections, despite the increased significance of visual material in the contemporary media landscape. This paper shows how studies of multimodal information activities can be designed

    Muscular expressions: profiling genes in complex tissues

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    Gene-expression profiling has yielded important information about simple systems, but complex tissues have not yet been widely profiled. Four recent studies of mammalian skeletal muscles have added to the catalogs of their gene expression differences, but have yet to lead to better understanding of the molecular processes underlying their physiological differences

    Estimated Returns from Farms of Large, Medium and Small Size of Business in the Spring Wheat Areas of South Dakota

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    Size of farm business is recognized by all farm management investigators and by many farmers as one of the most important factors making for success or failure in farming. A moderately large size of business, doubtless is more profitable in so-called normal times than is a small sized business. Size of business in this circular is not measured in acres only, as is common in certain sections where most of the land is fertile and tillable, and most of the farms are of the same type. Size of business cannot be measured accurately, nor by a single descriptive term such as acres. It includes the area farmed the area in crop land, the amount of productive labor employed, the amount of capital used, the rate of turnover of capital, the total production and the quality of production. Size of business may be increased by employing a laborer for productive work, by increasing the numbers of livestock, by increasing yields per acre, by doing work for hire outside the farm, etc. The purpose of this circular is to discuss the relative profitableness of a selected type of farm when operated as a business of different sizes. In the discussion six hypothetical farms are used for illustration. In the first group of three, a diversified farm, which is farmed rather intensively, is shown as a business of large size, of medium size, and of small size. The same plan is used for presenting the second group, a diversified farm which is farmed rather extensively

    Estimated Returns from Operating 800 acres in the Spring Wheat Area Under Four Different Plans - A Method of Determining What to Produce

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    The relatively low prices farmers receive for their products, and the continued high costs of interest, taxes, and the products farmers buy, increase the need of study of factors which tend to give the best possible net returns from a farm business. The purpose of this circular is to discuss the relative profitableness of different enterprises on diversified farms in the Spring Wheat Area of South Dakota. The plan of the circular is to show the organization and to give the estimated returns of four farms, on each of which the enterprises are of different relative importance. Three of the farms are assumed to be 800 acres in area. The fourth farm is assumed to be 800 acres in area but the size of business is increased by placing cattle out on pasture during the summer, a practice common to the area. Each of the hypothetical farms is very similar to someone actual farm from which records were secured. These similarities include acres of crops, numbers of livestock, amounts of power and equipment used, labor used, receipts and expenses, and income. The farms selected as patterns are common types within the area

    Tractor and Horse Power in the Wheat Area of South Dakota

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    A study of farm operations and farm management was made on 48 farms in Potter county during 1930, through the method of accounts kept daily by farm operators, assisted at regular monthly intervals by a resident field agent. During 1931 thirty other farmers within the spring wheat area of the state kept records of their tractors; and a survey by visits to farmers in the same area was made in 1931 and 1932, in which additional information about tractor and horse uses, performances, and costs was secured. The results of the Potter county study are being published as preliminary reports, of which this is the second. A part of the information secured during 1931 and 1932 is included in this report for the purpose of giving more reliable standards of performance of horses and tractors. The purpose of the report is to make available information which will aid farmers in deciding under what circumstances it is the more economical to use tractors or horses or a combination of both

    Information and experience: Audiovisual observations of reading activities in Swedish comprehensive school classrooms 1967–1969

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    This study investigates reading activities in Swedish primary school classrooms during the late 1960s. Sound and video recordings of 223 Swedish lessons held between 1967 and 1969 are used to analyse the activity of reading as taught and performed. The results indicate that the practice of informational reading, often based on finding predetermined, explicit "facts" in textbooks through individual, silent reading, was common. The practice of experiential reading, based on fiction, imagination and the joy of reading, was not only less common, but also often compromised by instrumental concerns. In the national curriculum of the time, the practice of informational reading was related to study skills and was intended to prepare all pupils for higher-level education. While often appearing over-proportioned, superficial and fragmented, these reading practices were still intentional objects of learning and teaching, and were grounded in the democratic and egalitarian ideals of Swedish post-war educational policy

    Indebtedness on 48 Potter County Farms, 1930

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    A study of farm operations and farm management was made on 48 farms in Potter County, South Dakota during 1930, through the method of accounts kept by the farm operators, assisted at regular monthly intervals by a resident field man. The study was made by the Department of Agricultural Economics of the South Dakota Agricultural Experiment station. The results of the study will be published first as preliminary reports, each dealing with only one or a few phases of the study. Data supporting certain statements is omitted in this report for want of space, but in most cases will be published in later reports. This, the first report, deals with indebtedness, one of the most important problems in farm management at present. Its chief objective is to make available information that will aid farmers in financing their business in the best manner
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