Browsing by Subject "Grain"
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Item Amtec power output optimization by investigating the grain size effect on its electrode materials(2006-12) Briggs, Justin B.; Lodhi, M. A. K.; Sill, Alan F.The Alkali Metal Thermal-to-Electric Converter (AMTEC) is perhaps one of the most desirable devices for directly converting heat into electrical energy, particularly for space applications. There has been a lot of research in the past for improving this device. Since AMTEC has been intended for deep space use its stability is expected to last a long time, 15 years or more. The two major components responsible for power output of AMTEC are the electrolyte and the electrode. In this work we focus research on the AMTEC electrodes, which could be improved further to reduce the power degradation as the time goes by in using the AMTEC. This study aims at improving the performance of the electrode by looking into the changes of the material properties inherent to it with respect to time. These parameters refer to the grain growth involved in the grain mobility model for electrode materials. If the grain size of the electrode material reaches a certain dimension, about 750 nm, the power output starts degrading fast. This is very important because this condition should not occur until after 15 years and corresponds to a power degradation percentage of 10 % for different electrode materials. The electrode materials studied in this work are Mo, TiN, RhW, and . It was found that adjusting four different paramters for these electrode materials gave a power degradation between 3 % to 22 %.Item Bioassay of various milling fractions of the grain sorghum kernel(Texas Tech University, 1967-08) Harden, Margarette LNot availableItem Biological value of grain sorghum with and without supplementation(Texas Tech University, 1963-08) Skinner, Betty LouIncreased awareness of the scope of the problems of feeding the constantly growing world population has been made apparent through information available from many sources which are striving to solve the problems on an Integrated basis. Anaphase has been placed on the necessity of the development of foods readily available in the local area, community, or nation which can help, especially the underdeveloped areas or communities, to meet the nutritional needs in order for them to become capable of being contributing members in the community. Within this concept Scrimshaw and coworkers (I) have recommended that any food products developed should be tested by four types of biological trials Including the testing of both the components and products on at least two animal species and the demonstration of the biological value of the protein content by animal growth studies. This study is, therefore, an investigation of the quality of protein in grain sorghum without and with the addition of protein rich foods available through surplus food commodities which offer the most desirable supplement to grain sorghum. The determination of the growth rate of rats on a diet of sorghum and sorghum supplemented with either nonfat dried milk or dried whole egg or a combination of these two foods was made to evaluate the use of grain sorghum in the development of a low cost food product.Item Comparison of milo and corn for feeding chicks(Texas Tech University, 1941-08) Puryear, Raymond WNot availableItem Effects of grain conditioners on the utilization of corn and milo by ruminants(Texas Tech University, 1982-05) Owsley, Michele Marie RunteNot availableItem Historical change in crop distributions in Texas and its potential application for modeling wildlife distributions(Texas Tech University, 2004-08) Tinkler, Dorothy ENot availableItem On the role of microstructure in ductile failure(2011-08) Ghahremaninezhad Mianji, Ali; Ravi-Chandar, K.; Mear, Mark E.; Liechti, Kenneth M.; Huang, Rui; Benzerga, AmineFailure in structural materials occurs initially by localization of deformation, and subsequently through a process of nucleation, growth and coalescence of voids. Predicting material failure requires a careful investigation of the different stages of damage evolution at the multiple scales. The main objective of this thesis is to explore the evolution of damage and to correlate this with the deformation of the material at the continuum and microstructural levels. This is accomplished through macroscopic measurements of strain evolution using digital image correlation and microscale measurements of strain and damage using optical and scanning electron microscopy. Three materials with different microstructure were examined. In oxygen-free, high-conductivity copper, a high-purity material without appreciable second phase particles, strain levels in the order of three were observed in the material without any trace of damage. Failure was observed to be triggered by plastic instability in the form of shear bands and the emergence of a prismatic cavity that grows in a self-similar fashion by an alternating slip mechanism. In Al 6061-T6, a material with a dispersion of second phase particles at a volume fraction of about 0.01, nucleation of damage does not appear until plastic strain levels of 0.5 to 1.0. Once damage in the form of particle fracture or decohesion at the interface initiates, subsequent failure follows by the void nucleation, growth and coalescence; but, dominated by the fluctuations in the distribution of second phase particles, final separation occurs in a highly localized layer of material on the order of the grain size, corresponding to a small increase in the overall strain. In nodular cast iron, a material with an initial porosity of about 0.10, growth of voids was observed initially, but this was terminated by a transition of the deformation into a localized region. Phenomenological models based on strain-to-failure and micromechanical models based on a mechanistic description of the microscale deformation are evaluated in light of the above examination of failure in these three classes of materials.Item Parametric study of LCROSS impact plume(2013-12) Lamb, Justin Meredith; Goldstein, David Benjamin, doctor of aeronauticsIn 2009, NASA's LCROSS mission impacted Cabeus Crater near the Lunar South Pole with the spent Centaur upper stage rocket. The impact was observed by the trailing sheperding spacecraft (S-S/C) that impacted the moon 250 seconds after the Centaur impact. The main objective of the LCROSS mission was to verify the existence of water ice in the lunar regolith---the subsequent analysis of the data confirmed water ice present in the crater. The analysis of the S-S/C instrument data suggested that the plume consisted of two components: a central "spike" component and a thin, outward "cone" component. A model has been developed at The University of Texas at Austin improve the analysis of the data obtained by the S-S/C. This model is created with a free-molecular ballistic grain code that involves simulating individual regolith grains in the debris plume through grain-heating and grain-movement models and then modeling the spectral radiance properties of the grains as observed by the S-S/C. Mie scattering theory is used to model scattering and absorption of incoming solar radiation by the particles in the plume assuming they are perfect spheres. The UT LCROSS code was utilized in a parametric study that evaluated the effect of variations in assumed model plume parameters on the modeling of S-S/C UV-VIS instrument observations. The plume parameters were chosen based on the assumption that the dust plume was split into two components: a central spike and a surrounding high angle cone. The following parameters were varied: the spike and cone angles, the spike and cone grain radius distributions, and the spike mass fraction. The following parameters could be varied but were given fixed values: ice fraction between plume components, ice grain purity, albedo, and ice fraction in plume. The impact of these plume parameters upon plume brightness and blue/red color ratio was determined. Two grain models were used. In the initial grain species model all grains have a soil core surrounded by a thin ice shell. In the second, two species model two grain types were utilized: a pure ice grain component and a pure soil grain component.Item Uses of grain sorghum as food for humans(Texas Tech University, 1962-08) Boren, Angela RattanNot availableItem Uses of grain sorghum in Asian diets(Texas Tech University, 1973-08) Parial, Priscilla AndresNot availableItem White Corn Versus Yellow Milo for Fattening Pigs(Texas Tech University, 1941-08) McWhirter, DaleNot Available.