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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

American Scientists, Americanist Archaeology: The Committee on Radioactive Carbon 14

Baich, Keith David 01 January 2010 (has links)
Willard Libby's development of carbon-14 dating at the University of Chicago immediately following World War II provided an unprecedented opportunity for the collaboration of archaeologists with a physical chemist. Libby's need for archaeological samples to test the dating process (1947-1951) meant that he relied upon the Committee on Radioactive Carbon 14, formed by the American Anthropological Association, for datable materials, as well as for assistance in all other archaeologically related aspects of the testing phase. The committee, under the leadership of archaeologist Frederick Johnson, served the mandated function of providing assistance to Libby, but simultaneously endeavored to utilize the new dating method to promote the development of the authority of anthropological professional organizations and further establish Americanist archaeology in a national and global context. Johnson's and the committee's approach to collaboration was informed by an understanding of opportunities provided by the postwar restructuring of the sciences. The purpose of the present study is to provide a history of the Committee on Radioactive Carbon 14 (1948-1952) as well as a to provide the context necessary to describe the bureaucratic and scientific goals of the committee. Frederick Johnson's career, and the manner in which it reflected general trends in twentieth century American anthropology, is discussed in detail, and utilized to present an explanation of his actions as committee chair. Willard Libby's development of carbon-14 dating is also discussed in detail, particularly in regard to his request for assistance from the archaeological community and subsequent collaborative work. The undeniable influence of carbon-14 dating on archaeological practice worldwide, and Libby's acceptance of the Nobel Prize in Chemistry (1960) for his development of the dating method, has provided reason enough for a plethora of articles and book length studies regarding carbon-14 dating. Yet, little has been written about the Committee on Radioactive Carbon 14 and its place in an analysis of the bureaucratic and collaborative science of the American mid-century. It is for this reason that the present study was undertaken.
412

Johnson City, Tennessee Zoning Map 1983

Johnson City Planning Commission 27 September 1983 (has links)
Zoning map for the city of Johnson City and the outlying areas. Original map was drawn January 11, 1972 and was originally adopted by the city April 20, 1972. This revised map is a duplicate of the original and was produced September 27, 1983. This was likely when the hand drawn lines were added to update the zoning districts. Most main streets are also labeled with arterial streets notated by dotted lines. While not included in the legend, it is likely that R stands for residential and I for industrial. East Tennessee State University can be found in zone R-6 located next to Greenwood Drive. The left portion of the map has been cut as you can see by the title Johnson City partially missing. No accompanying maps are found in the collection. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. / https://dc.etsu.edu/rare-maps/1002/thumbnail.jpg
413

Johnson City Annexations, 1960-2006

Johnson City GIS Division 08 May 2006 (has links)
Produced by the Johnson City GIS Division on May 8, 2006, this map denotes the annexations of Johnson City and the surrounding area from 1960 to 2006. The map scale indicates a ratio of 1:24,000. In the text box on the left side, the ID, date, and annexation names are listed. As part of the legend, each 5 year annexation period is color coded. Physical copy resides with Johnson City, Geographic Information Systems Division. 1 in= 2000’ / https://dc.etsu.edu/rare-maps/1057/thumbnail.jpg
414

Temperature-dependent impact properties of 3D printed 15-5 stainless steel

Sagar, Sugrim 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Since the conception of three dimensional (3D) printing circa 40 years ago, there has been the proliferation of several additive manufacturing (AM) technologies that enable its use in everyday applications such as aerospace, medicine, military, oil and gas and infrastructure. In order to improve its applicability and growth, 3D printed materials are subjected to the same or even higher levels of scrutiny for its mechanical behavior as its conventionally manufactured counterpart. One of the most important mechanical properties is toughness or the ability of a material to undergo large strain prior to fracture when loaded. The toughness of a material can be correlated to its impact energy or the increase in internal energy due to impact. In this study, the impact properties, including the toughness of 3D printed 15-5 stainless steel were investigated at low temperature (77 K), room temperature (298 K) and high temperature (723 K) using experimental and numerical modeling of the Charpy impact test. In addition, ballistic impact simulations were performed to determine the applicability of 3D printed 15-5 stainless steel in the defense industry. The 15-5 stainless steel specimens were printed (horizontal-build) using the direct metal laser sintering (DMLS) technique, cooled or heated to the specified temperature, then tested in accordance with the ASTM E23-2016b [1] standard. The Johnson-Cook (J-C) phenomenological material model and fracture parameters were used in the numerical modeling. The cross-sectional microstructures of surfaces and impact energies of the Charpy impact test were examined. For the ballistic impact simulations, a 3D printed 15-5 stainless steel typical plate was investigated at the same temperatures as the Charpy impact test. A typical missile using the J-C properties at room temperature (298 K) was assigned an initial velocity of 300 ms-1 for each plate temperature. The fracture surface investigation (microsurface analysis as well as visual inspection) and impact energy values of the Charpy impact test show that the 3D printed 15-5 stainless steel exhibited brittle behavior at low and room temperatures, but transitioned into a more ductile behavior at high temperature. At 77 K, 298 K and 723 K, the experimental Charpy impact test results were 0.00 J/cm2, 6.78±4.07 J/cm2 and 50.84±3.39 J/cm2 respectively; whereas the simulated impact energy were 1.05 J/cm2, 10.46 J/cm2 and 47.07 J/cm2 respectively. Hence, the impact energy for the experimental and numerical simulations were in good agreement; especially at higher temperatures. Consistent with the results from the Charpy impact test, the ballistic impact simulations show an increase in the impact energy, elastic plastic strain and deflection of the plate with an increase in temperature indicating brittle-to-ductile behavior. The high exit velocity at low and room temperature may not make the plate attractive in defense in its current configuration; however, at the high temperature, the exit velocity reduction was significant.
415

"The Jaws of Mars are Traditionally Wide ... And His Appetite Is Insatiable": Truman, the Budget, and National Security

Strong, Edward Trowbridge 31 July 2019 (has links)
No description available.
416

Mesh Regularization Through Introduction of Mesh Size based Scaling Factor using LS Dyna Explicit Analysis

Patro, Abinash January 2019 (has links)
No description available.
417

Modeling Micro-Cracked, Salem Limestone during Monotonic Impact in Abaqus Explicit

Frederick, Samantha 11 August 2017 (has links)
A finite element model is developed in Abaqus Explicit to determine the resistance of Salem Limestone with three levels of initial micro-cracking to high-speed, monotonic impact. A comprehensive description of the model development is included, and the model is validated by comparing simulation impact results to known penetration depths during a mesh refinement study. The uniaxial compression simulations were performed to correlate the HJC damage parameter to the uniaxial compressive strengths from mechanical test data. Then, the HJC damage parameter is compared to the unconfined compression strengths to correlate the micro-crack damage levels. Subsequently, the model was used to determine the correlation of the penetration depths at the finite damage levels. In conclusion, the model described in the paper can adequately predict the penetration depths of the projectiles for a range of micro-crack damage levels. The micro-cracking did/did not affect the penetration depth.
418

Langston Lost & Found

Lange, Shara K. 01 December 2019 (has links)
No description available.
419

The Effects of Laser Shock Peening on the Residual Stress and Corrosion Characteristics of Magnesium Alloy AZ91D for use as Biodegradable Implants

Russo, James January 2012 (has links)
No description available.
420

The Crucible of Texas Politics: An Analysis of the United States Senatorial Primaries of 1941 and 1948.

Spradlin, Ginger McGoldrick 07 May 2011 (has links) (PDF)
Lyndon Johnson's opponents used the outcome of his 1948 senatorial bid to demonstrate his dishonesty. This win by eighty-seven disputed votes gave him the derogatory title, "Landslide Lyndon." Johnson's initial senate campaigns in 1941 and 1948 are examined for Texas Politics as usual. Upon Senator Sheppard's death in 1937, a special election precipitated with Martin Dies, Gerald Mann, Lyndon Johnson, and W. Lee O'Daniel as the candidates. Although this election has not received the notoriety of 1948, it exemplifies Texas Politics as usual where thousands of manipulated votes resulted in O'Daniel's late victory. Johnson's next race for the senate came in 1948. He ran against George Peddy and Coke Stevenson. This expensive campaign rested upon two hundred two invalid votes from Jim Wells County. In reality, tens of thousands of manipulated votes on both sides resulted in litigation making its way to the United States Supreme Court.

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