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Flutter tests of modified SB2U model in 16-foot tunnel

Description: Report presenting testing of the flutter characteristics of the SB2U model conducted after the model had been modified to lower its flutter speed. The model was tested to destruction and the flutter speed was measured throughout.
Date: August 1943
Creator: Theodorsen, Theodore; Coleman, R. P. & Smith, N. H.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of a 1/6-scale model of the Bumblebee XPM missile at high subsonic speeds

Description: Report presenting the results of an investigation of a model of the Bumblebee XPM missile to determine the causes of booster-fin failures on full-scale missiles. Results indicated that failures of the fins were due to launching shoes which caused the missile to try at increasingly negative angles of attack as the Mach number increased.
Date: December 11, 1950
Creator: Nelson, Warren H.
Partner: UNT Libraries Government Documents Department

Vibration survey of blades in 10-stage axial-flow compressor: 1: static investigation

Description: From Summary: "An investigation was conducted to determine the cause of failures in the seventh- and tenth-stage blades of an axial-flow compressor. The natural frequencies of all rotor blades were measured and critical-speed diagrams were plotted. These data show that the failures were possibly caused by resonance of a first bending-mode vibration excited by a fourth order of the rotor speed in the seventh stage and a sixth order in the tenth stage."
Date: January 31, 1949
Creator: Meyer, André J., Jr. & Calvert, Howard F.
Partner: UNT Libraries Government Documents Department

Twisting of Thin Walled Columns Perfectly Restrained at One End

Description: "Proceeding from the basic assumptions of the Batho-Bredt theory on twisting failure of thin-walled columns, the discrepancies most frequently encountered are analyzed. A generalized approximate method is suggested for the determination of the disturbances in the stress condition of the column, induced by the constrained warping in one of the end sections" (p. 1).
Date: March 1938
Creator: Lazzarino, Lucio
Partner: UNT Libraries Government Documents Department

Effectiveness of Ceramic Coatings in Reducing Corrosion of Five Heat-Resistant Alloys by Lead-Bromide Vapors

Description: Note presenting testing to determine whether lead compounds in the combustion products of high-octane fuel are a contributing factor in causing failures of the heat-resistant alloy parts in aircraft exhaust systems. To obtain answers for five heat-resistant alloys, a test was devised in which the alloy specimens in an uncoated condition, in a preoxidized condition, and with three different ceramic coatings were exposed for 6 hours to lead-containing vapors in an air atmosphere at 3 different temperatures.
Date: June 1951
Creator: Moore, Dwight G. & Mason, Mary A.
Partner: UNT Libraries Government Documents Department

Failure of Materials Under Combined Repeated Stresses With Superimposed Static Stresses

Description: Note presenting a review of experiments on biaxial alternating stresses and simple combinations of static stress with alternating stress, which is shown to lead to a general criterion for the effect of static stress on the permissible amplitude of alternating stress. Tests were performed to determine the effect of static compression on alternating torsion, which is the one simple combination that had not been previously investigated. The results agree with the criterion.
Date: November 1955
Creator: Sines, George
Partner: UNT Libraries Government Documents Department

An Analysis of the Effect of Environmental and Systems Complexity on Information Systems Failures

Description: Companies have invested large amounts of money on information systems development. Unfortunately, not all information systems developments are successful. Software project failure is frequent and lamentable. Surveys and statistical analysis results underscore the severity and scope of software project failure. Limited research relates software structure to information systems failures. Systematic study of failure provides insights into the causes of IS failure. More importantly, it contributes to better monitoring and control of projects and enhancing the likelihood of the success of management information systems. The underlining theories and literature that contribute to the construction of theoretical framework come from general systems theory, complexity theory, and failure studies. One hundred COBOL programs from a single company are used in the analysis. The program log clearly documents the date, time, and the reasons for changes to the programs. In this study the relationships among the variables of business requirements change, software complexity, program size and the error rate in each phase of software development life cycle are tested. Interpretations of the hypotheses testing are provided as well. The data shows that analysis error and design error occur more often than programming error. Measurement criteria need to be developed at each stage of the software development cycle, especially in the early stage. The quality and reliability of software can be improved continuously. The findings from this study suggest that it is imperative to develop an adaptive system that can cope with the changes to the business environment. Further, management needs to focus on processes that improve the quality of the system design stage.
Date: August 2001
Creator: Zhang, Xiaoni
Partner: UNT Libraries

A Test of Catastrophe Theory Applied to Corporate Failure

Description: Catastrophe theory (CT) is a relatively new mathematical theory that comprehensively describes a system exhibiting discontinuous behavior when subjected to continuous stimuli. This study tests the theory using capital-market data. The data is a time series of stock returns on firms that filed for Chapter 11 reorganization during 1980-1985. The CT model used is based on a corporate failure model suggested by Francis, Hastings and Fabozzi (1983). The model predicts 1) as the filing date approaches, there will be a structural shift in the underlying stock-return generating process of the filing firm, and 2) firms with lower operating risk will have a smaller jump than firms with higher operating risk, corresponding to their relative positions within the bifurcation set of the catastrophe cusp.
Date: August 1987
Creator: Gregory-Allen, Russell B. (Russell Brian)
Partner: UNT Libraries

Regulatory Incentives for Electricity Transmissions-Issues and Cost Concerns

Description: This report will focus on issues related to the need for transmission incentives, and consumer cost concerns related to these incentives. Given the changes that FERC cites in the electric industry, the question arises as to whether the need for transmission incentives continues. FERC is bound by EPACT to make incentives available, and is not proposing to end the incentives. However, with concerns raised over the effects of transmission incentives on consumer rates, implications of related federal policies on the electric power sector, additional FERC regulatory policies for transmission, and the aging of electricity infrastructure among key issues, the need for continuing transmission incentives may be a matter for Congress to consider.
Date: October 28, 2011
Creator: Campbell, Richard J.
Partner: UNT Libraries Government Documents Department

The Influence of Construction Step Sequence and Nonlinear Material Behavior on Cracking of Earth and Rock-Fill Dams: Preliminary Study

Description: Summary: This report is a review of the materials, specifications, procedures, equipment, and testing pertinent to construction and compaction control of the earth-fill embankment of Littleville Dam, Westfield River, Mass., constructed by the U. S. Army Engineer Division, New England.
Date: December 1970
Creator: Strohm, William E. & Johnson, Stanley J.
Partner: UNT Libraries Government Documents Department

ASME code ductile failure criteria for impulsively loaded pressure vessels

Description: Ductile failure criteria suitable for application to impulsively loaded high pressure vessels that are designed to the rules of the ASME Code Section VI11 Division 3 are described and justified. The criteria are based upon prevention of load instability and the associated global failure mechanisms, and on protection against progressive distortion for multiple-use vessels. The criteria are demonstrated by the design and analysis of vessels that contain high explosive charges.
Date: January 1, 2003
Creator: Nickell, Robert E.; Duffey, T. A. (Thomas A.) & Rodriguez, E. A. (Edward A.)
Partner: UNT Libraries Government Documents Department

IN-PILE MECHANICAL FAILURE OF MTR FUEL ASSEMBLIES

Description: Fuel assembly failures that have occurred as the result of mechanical deficiencies of the assemblies are described. The causes of the failures are analyzed, and measures taken to avoid additional failures are described. (D.C.W.)
Date: July 1, 1963
Creator: Harrison, L.J.
Partner: UNT Libraries Government Documents Department

SHOCK AND VIBRATION IN NAVAL REACTORS

Description: The problem of designing a reactor to withstand the shocks and vibration incident to shipboard service in Naval craft consists of three principal parts. First the loads must be defined in some rational manner, then the responses of the various reactor structures to these loads must be predicted, and finally the responses must be compared to some damage criteria to determine whether the design is adequate or not. A brief discussion of each of these major parts is given, and then a specific example is worked through to illustrate what is involved in the whole process. (auth)
Date: October 31, 1957
Creator: Mains, R.M.
Partner: UNT Libraries Government Documents Department

Hurricanes and Electricity Infrastructure Hardening

Description: This report discusses the measures undertaken by electric utilities to prevent or mitigate power outages resulting from severe weather events. Power lines and transformers used to provide electricity to customers are particularly susceptible to damage due to their exposure to the elements. The loss of life and extensive damage seen so far in the 2017 hurricane season has refocused the attention of Congress on the destructive potential of such storms. High winds, rain, and coastal surges can combine to create floods which exacerbate damage from hurricanes.
Date: September 20, 2017
Creator: Campbell, Richard J.
Partner: UNT Libraries Government Documents Department

Repair or Rebuild: Options for Electric Power in Puerto Rico

Description: This report explores several alternative electric power structures to PREPA for meeting the electricity services and needs of Puerto Rico. The ability of Puerto Rico and its citizens to assume the burden of paying for a rebuilt (and possibly restructured) electricity system is doubtful. Modernizing Puerto Rico’s grid, and taking the next steps to incorporate resiliency, could be expensive. None of the options discussed provides a silver bullet solution to the issues of the grid in Puerto Rico. Congress may consider whether the efforts to restore electric power in Puerto Rico need to progress beyond simple restoration of electricity, and require new investment and oversight by the federal government.
Date: November 16, 2017
Creator: Campbell, Richard J.; Clark, Corrie E. & Austin, D. Andrew
Partner: UNT Libraries Government Documents Department

Routes to failure in rotating MEMS devices experiencing sliding friction

Description: Gear systems rotating on hubs have been operated to failure using Sandia`s microengine as the actuation device. Conventional failure modes such as fatigue induced fracture did not occur, indicating that the devices are mechanically extremely robust. The generic route to failure observed for all rotating devices involves sticking of structures that are in sliding contact. This sticking evidently results from microscopic changes in the sliding surfaces during operation. The rate at which these changes occur is accelerated by excessive applied forces, which originate from non-optimized designs or inappropriate drive voltages. Precursors to failure are observed, enabling further understanding of the microscopic changes that occur in the sliding surfaces that ultimately lead to failure.
Date: August 1, 1997
Creator: Miller, S.L.; LaVigne, G.; Rodgers, M.S.; Sniegowski, J.J.; Waters, J.P. & McWhorter, P.J.
Partner: UNT Libraries Government Documents Department