Digitized Theses and Dissertations (1922–2004)
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This collection contains Texas A&M University theses and dissertations written between 1922 and 2004.
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In 2004, the Texas A&M University’s Office of Graduate and Professional Studies (OGAPS) began requiring electronic submission of theses and dissertations. Prior to this, Texas A&M University theses and dissertations were bound and shelved at the University Libraries. The theses and dissertations in this collection were digitized by the University Libraries.
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Item 0-g annular flow and 1-g stratified flow single component two-phase condensation modeling and experiments(Texas A&M University, 1993) Baranek, PascaleNot availableItem A 1.8V 10-bit 10MS/sec pipelined ADC(Texas A&M University, 1997) Gunay, Zeki SezginThe objective of this thesis is to develop a pipelined analog-to-digital converter which operates under a single supply voltage of 1.8V and is capable of resolving 10 bits at a rate of IOMS/sec. Although the overall architecture of the developed pipelined converter is a general one at the system level, a family of new low-voltage building blocks is proposed. The amplifiers and comparators which are designed to perform interstage processing have high gain-bandwidth products and they are capable of operating at supply levels of less than the initial specification of 1.8V. To test the concepts used to design important blocks such as amplifiers and comparators, a chip prototype amplifier is fabricated in a 1.2nm standard CMOS process and is tested to be functional. The entire converter system is designed using a 0.5/,nm standard CMOS process and its layout is completed. A patent application is filed for the offset cancelation utilizing capacitive levelshift devices for single-ended amplifiers.Item A 1.8V 2-2 cascade Sigma-Delta modulator for high speed applications(Texas A&M University, 2002) Lee, Kye-ShinIn order to satisfy today's most important requirements of the A/D and D/A converters that are low voltage and high speed operation, a low voltage and high speed circuit solutions for [] modulators are strongly demanding. However, simply reducing the supply voltage and increasing the clock frequency of the [] modulator will introduce severe constraints to the design. In this thesis, a 1.8V 2-2 cascade [] modulator with 1MHz signal bandwidth is realized by employing a modified [] modulator structure which can limit the output swing of the integrator within half the reference voltage. As a result, the supply voltage can be easily reduced without any degradation of the modulator performance. Moreover, the slew rate and bandwidth requirements of the OpAmp are much more alleviated. Also, using only single bit quantizers in each stage, linearity and matching problems are not critical. Circuit level simulation results show a peak SNR of 77.3dB and a peak SNDR of 72.1dB which corresponds to a nearly 13 bit resolution.Item A 100-kc modulation system for an EPR microwave spectrometer(Texas A&M University, 1964) Stewart, Frank EdwinNot availableItem A 113 L/min ambient aerosol sampler for collection of thoracic and respirable fractions(Texas A&M University, 1981) Rue, Clayton MatthewNot availableItem The 1400-1240 A absorption system of carbon dioxide(1971) Petty, William Restelle; Coon, Jesse B.; Hedges, R. M.; Klipple, E. C.Item The 1794 Wreck of the Ten Sail, Cayman Islands, British West Indies : a historical study and archaeological survey(1993) Leshikar, Margaret Elaine; Bass, George F.; Crisman, Kevin J.The French Revolution had begun in 1789 and by 1793 Britain and France were engaged in war. Hostilities extended to their world-wide possessions, and to the high seas where each nation strived to capture the other's naval and merchant ships as prizes. In November 1793, the French Navy's 12-pounder frigate l'Inconstante was captured off the French West Indian colony of St. Domingue, taken to Jamaica and sold into His Majesty's Service as the Convert. The Royal Navy frigate was to escort and protect a produce-laden convoy of 55 merchantmen from Jamaica to ports in Britain; three vessels bound for America would join them. The greatest danger to the fleet, however, was not to be the French, for on 8 February 1794 the Convert, together with nine of the merchant ships, wrecked on the windward reefs of Grand Cayman. This dissertation investigates the history and archaeology of the shipwreck disaster which has survived in Cayman Islands folklore as the legend of the Wreck of the Ten Sail. But current research indicates that the incident has historical significance that exceeds the bounds of Cayman's national attention. It is tied to the history of Britain and France in the French Revolutionary Period, and is evidence of the wide geographical distribution of European war and trade at the close of the eighteenth century. This study is a presentation of history, archaeology and folklore. Research entailed archival work in Jamaica, Britain and France; archaeological survey and mapping of shipwreck sites scattered over the reefs of Grand Cayman's East End; and oral history interviews with older Caymanians whose parents and grandparents told them the story of the Wreck of the Ten Sail. Results of the investigation include a better understanding of the historical and geographical context of the shipwreck disaster; a more thorough and accurate account of the event; specific knowledge of the locations and nature of archaeological remains; recovery, conservation, and analysis of artifacts; and an awareness of the enduring effects of the Wreck of the Ten Sail on the Cayman Islands.Item The 1794 Wreck of the Ten Sail, Cayman Islands, British West Indies : a historical study and archaeological survey(1993-12) Leshikar-Denton, Margaret E.; Bass, George Fletcher; Crisman, Kevin James; Hamilton, Donny Leon; Grider, Sylvia Ann; Shafer, Harry J.The French Revolution had begun in 1789 and by 1793 Britain and France were engaged in war. Hostilities extended to their world-wide possessions, and to the high seas where each nation strived to capture the other's naval and merchant ships as prizes. In November 1793, the French Navy's 12- pounder frigate l'Inconstante was captured off the French West Indian colony of St. Domingue, taken to Jamaica and sold into His Majesty's Service as the Convert. The Royal Navy frigate was to escort and protect a produce-laden convoy of 55 merchantmen from Jamaica to ports in Britain; three vessels bound for America would join them. The greatest danger to the fleet, however, was not to be the French, for on 8 February 1794 the Convert, together with nine of the merchant ships, wrecked on the windward reefs of Grand Cayman. This dissertation investigates the history and archaeology of the shipwreck disaster which has survived in Cayman Islands folklore as the legend of the Wreck of the Ten Sail. But current research indicates that the incident has historical significance that exceeds the bounds of Cayman's national attention. It is tied to the history of Britain and France in the French Revolutionary Period, and is evidence of the wide geographical distribution of European war and trade at the close of the eighteenth century. This study is a presentation of history, archaeology and folklore. Research entailed archival work in Jamaica, Britain and France; archaeological survey and mapping of shipwreck sites scattered over the reefs of Grand Cayman's East End; and oral history interviews with older Caymanians whose parents and grandparents told them the story of the Wreck of the Ten Sail. Results of the investigation include a better understanding of the historical and geographical context of the shipwreck disaster; a more thorough and accurate account of the event; specific knowledge of the locations and nature of archaeological remains; recovery, conservation, and analysis of artifacts; and an awareness of the enduring effects of the Wreck of the Ten Sail on the Cayman Islands.Item The 1908 Conference of Governors on the Conservation of Natural Resources(Texas A&M University, 1971) Johnson, Gloria ChildsNot availableItem 1973 projections of consumption, production, prices and crop values for Texas winter lettuce and early spring onions(Texas A&M University, 1970) Furrh, Samuel RogerNot availableItem 1984 Deep Sea Roundup: an analysis of participants' characteristics, attitudes, and expenditures(Texas A&M University, 1988) Arneson, Lynn ANot availableItem The 1993 basals versus the 1987 versions : examining four reading series for the proportion of literature-based stories, adaptions, and award-winning literature(1994) Anderson, Dianna Dillon; Norton, Donna E.; Many, Joyce E.; Stansell, John C.; Willson, Victor L.In the past, evaluations of basal reading series have suggested using less tightly controlled stories, usually written by the publishing companies to fit a readability formula, and more on using children's literature in the anthologies. This would also eliminate the need for extensive adaptions that have characterized those reading series. This study examined literature-based stories found in first-grade student anthologies (basals), the adaptions made to those stories, and any award-winning stories found in that literature. Four current reading series were examined: Houghton Mifflin, Scott Foresman, Macmillan/McGraw Hill, and Harcourt Brace Jovanovich. The findings answered these questions: 1) What is the difference in the proportion of literature-based stories between the 1987 editions of the first-grade basal reading series and the 1993 editions? 2) What is the difference in the proportion of trade book stories adapted and the types of adaptions made between the 1987 first-grade basals and the 1993 first-grade basals? 3) What is the difference in the proportion of award-winning literature between the 1987 editions of first-grade basal reading series and the 1993 editions? This was a descriptive study in which frequency distributions and percentage scores were calculated. Results indicated there were significant differences in the proportion of literature-based stories, and adaptions across the editions. In 1987, 17% of the stories in the firstgrade basal were literature-based, while in 1993, that proportion increased to 87%. In 1987, 92% of the trade book stories in the basal were adapted, with sentence adaptions being the most common type of adaptions. In 1993, 14% of the trade book stories were adapted, with punctuation adaptions being the most common type. The findings from this study did not indicate a significant difference in the proportion of literature that had won awards between 1987 and 1993. In 1987, only five percent of the total proportion of literature won an award. In 199 3, even though there was more literature included in the basal readers, the percentage of awardwinners remained the same, at five percent.Item The 1993 nutrition label: development of a rating system and a perspective by nutrition and food industry professionals(Texas A&M University, 1994) Osborn, Lacye AnnThe objectives of this study were to develop a nutrition scoring system which would combine the nutritional information on the new label into a single number, to identify strengths and weaknesses of the new nutritional labels according to nutrition and food industry professionals and to determine if any differences exist between professionals' perception of the nutritional label. A scoring system was designed using the components on the new nutritional label. Labels from main dish products were used for scoring. Each component was given points of 0, 25, 50, 75 or 100 according to the amount present. A score was assigned based on an average of the points. When incorporated with the existing label, the scoring system could be very useful to consumers while still providing specific information for individuals. By making the label easier to understand, it would add to the consumer's willingness to use the label. A questionnaire to assess attitudes toward each component on the new nutritional label was sent to members of the American Dietetic Association (ADA, n--1220)andthelnstituteofFoodTechnologists(IFT,n--441). Atotalof464 professionals (28%) responded of which 79% and 22% were ADA and IFT members, respectively. Responses varied with subject age, position, job function and area of practice or responsibility. With the exception of protein, ADA respondents considered each component of the label to be more important than did I]FT respondents. Both groups ranked kilocalories (kcal), total fat, and sodium to be more important components and vitamin A and C and sugars less important. ADA respondents indicated that percentage kcal from fat and other vitamins and minerals should be added to the label. IFT respondents were concerned with the process and the costs required to modify the labels. In conclusion, the nutritional components on the new label were acceptable to this sample of the population. The observation that differences of opinions within the groups of professionals were not as widespread as expected is important. The less variation seen within the parties involved in label policy, the easier it should be to produce nutrition messages which consumers will understand.Item The 1994 Net Ban Constitutional Amendment: a case study of marine fisheries management in Florida(Texas A&M University, 1996) Grimes, Shepherd RussellOn November 8, 1994 the Florida electorate voted 2,876,091 to 1,135,110 in favor of proposed amendment #3 to the state constitution. The amendment effectively reallocated the state's nearshore fisheries to predominantly recreational "hook and line" anglers through a ban on the use of certain net gear. The amendment was initiated via a petition drive supported by a coalition of recreational fishing and conservation groups. These interest groups have continued to play an increasingly important role in the management of Florida's marine fisheries resources. This thesis presents a case study of the issues and events leading to the electoral approval of Article X, Section 16 of the Florida Constitution. An in-depth look at the case is presented, highlighting critical issues and occurrences. Also, theoretical explanations for case findings are presented. The vigor of related interest groups was the key to the initiation and success of the referendum. For years, well-organized groups representing the commercial industry maintained a considerable presence and influence in state government. Focusing much of their efforts on the Governor and Cabinet, and pursuing rule challenges, these groups prevented the implementation of numerous regulations supported by recreational interests. After limited success through institutional channels, recreational interests formed a coalition and initiated a petition drive that succeeded in getting the proposed amendment on the ballot. The established institutions responsible for marine fisheries management in Florida failed to appreciate the strength of organized recreational fishing interests within the state. Although its inability to sufficiently address the issue was partially attributable to the institutional hierarchy, the Florida Marine Fisheries Commission must better appreciate the role of such interest groups.Item 2-D discrete element modeling of unconsolidated sandstones(Texas A&M University, 2001) Franquet Barbara, Javier AlejandroIn this work unconsolidated sands saturated with heavy oil were modeled using a discrete element numerical model, (DEM). The DEM code was built in Mathematica ♭ programming language. The strain-stress behavior of biaxial tests using the code developed in this thesis is compared to the results of triaxial tests performed in cylindrical core samples of unconsolidated sandstones saturated with heavy oil. The discrete element model treats the sand as a two dimensional assembly of particles. The displacements and velocities of each particle are calculated in order to determine local rearrangements during deformation. The kinematics of the system is performed in small time steps where force and torque balance is calculated for each disk. Several grain forces are simulated in this DEM model when the unconsolidated sand, saturated with heavy oil, is under a deviatoric loading condition. The contact forces are modeled as spring and dashpot forces, and they are applied in the contact point in the normal and tangential directions. Friction viscous forces are included for linear displacements and for rotational movements. The viscous forces generated by the movements of very close neighborhood particles are also considered in the model. The DEM code is also capable of modeling capillary forces between grains when the assembly is considered partially saturated, and the interstitial liquid is filling the porous space as a discrete liquid bridge between particles. Four boundary walls surround the particle assembly. The bottom boundary is considered flat, frictionless, and static while the top boundary is a stress controlled wall. The other two vertical boundaries are under a confining distributive force, and these walls can be modeled as two parallel flexible boundaries or as a simple horizontal force condition distributed to the boundary particles. Compressibility and apparent Young's modulus are compared between the DEM results and the laboratory geomechanical data. This investigation is part of ongoing research to obtain the micro-mechanical parameters needed for future hydraulic fracture propagation studies in an unconsolidated formation impregnated with heavy oil.Item 2-dimensional numerical simulations for the wave-wake-body interactions around circular cylinders in motion near seabed(Texas A&M University, 1999) Tavassoli, ArminThe 2-dimensional, viscous and incompressible flow past a circular cylinder is investigated by solving the Navier-stokes equation. solved using CFD (Computational Fluid These equations are numerically Dynamics) methods on an overlapping multiblock grid system. In this thesis, several flow configurations, such as stationary and oscillating cylinder, were studied in order to predict and to understand the hydrodynamic forces. The results from the different simulations were compared with available experimental and numerical data, which confirmed the correctness and accuracy of the present method. The numerical computations successfully captured many important flow features for the various types of flow conditions. The present program code proves to be a powerful tool, by enabling the study of numerous interesting and useful research topics related to fluid-structure interactions, thereby, it will contribute to a better design of offshore structures.Item 20 MHz IF bandpass switched capacitor [] modulator using a high performance OTA with NCFF compensation scheme(Texas A&M University, 2001) Thandri, Bharath KumarSwitched capacitor (SC) circuits are widely used in many applications because of their accuracy and ease of integration in CMOS technology. They are not suitable for operation in high frequencies because of the settling time limitation of amplifiers. High frequency switched capacitor circuits pose challenging design specifications on the amplifiers which cannot be met by conventional circuit design techniques. High amplifier gain is required for an accurate output, whereas fast settling time is obtained by a high gainbandwidth (GBW) product. Amplifiers that use cascading of gain stages for obtaining high gain require some robust frequency compensation schemes, and usually have a low GBW, resulting in a slow settling time. This work proposes a new compensation scheme for high gain wideband amplifiers - No Capacitor Feed Forward (NCFF) compensation scheme. NCFF scheme uses pole-zero cancellation to obtain high gain, high GBW and a good phase margin. Left half plane (LHP) zeros produced due to the feedforward path causes a positive phase shift and is used to cancel the negative phase shift of poles. Fully differential and single ended operational transconductance amplifiers (OTA) using the proposed NCFF compensation scheme have been designed and fabricated using CMOS AMI 0.5 []m technology. The fully differential OTA has a gain of 97 dB, GBW of 350 MHz and a phase margin of around 90°. Sigma delta [ ] modulators use oversampling and quantization noise shaping to obtain a high dynamic range. They are well suited for use in radio and cellular systems to directly convert the narrowband IF signal centered at high frequencies to digital domain. Switched capacitor implementation of a [ ] modulator requires a fast settling amplifier to operate at high IF frequencies. The design and implementation issues of a 20 MHz IF, 80 MHz clock, fourth order switched capacitor bandpass [ ] modulator are discussed in detail. The modulator uses a high performance OTA using the proposed NCFF compensation scheme and it has been designed and fabricated using 3.3V CMOS TSMC 0.35 []m technology. The bandpass [ ] modulator has a peak SNR of 70 dB (post-layout simulations).Item The 2000 A absorption system of NH₃, ND₃, and NT₃(1964) Young, Bernard Theodore; Coon, Jesse B.; Basye, Robert E.; Eisner, Michael; Potter, James G.The absorption spectra in the 2000 A region of NH₃ and ND₃ taken by B. L. Landrum (1) and of NT₃ taken by J. R. Henderson (2) are examined, with emphasis on the temperature sensitive bands. Three new ND₃ and four new NT₃ bands are observed. While most of the previous band assignments are left unchanged, in this work one NH₃, three ND₃, and three NT₃ assignments are changed. New assignments are made for two ND₃ bands and two NT₃ bands. In the composite of Landrum's, Henderson's, and this work, the number of temperature sensitive bands identified is eight for NH₃, nineteen for ND₃, and eighteen for NT₃. Of the ND₃ bands, twelve correspond to transitions from ground state levels which involve [nu]"₁ or 2[nu]"₁ in combination with inversion levels. There are six levels of ND₃ known from infrared spectra which may be calculated from the present data. The average disagreement is about 2 cm⁻¹. In addition nine ground state vibrational levels have been determined which were not previously known. Except that fewer bands are observed for ND₃ and NT₃, results are similar to those of ND₃. The presence of [nu]"₁ in the "hot" bands leads one to expect the appearance of [nu]'₁ in the exited state. If [nu]'₁ is present, it is overlapped. Both NH₃ and ND₃ absorption intensifies for the (0000) <-- (0 v"₂ 00) transitions, where v"₂ = 0⁺, 1⁺, 2⁺, and 3⁺, are experimentally measured, and the corresponding relative intensities are calculated using the Franck-Condon Principle. The average disagreement is 17%. This is much lower than might be expected since the equilibrium H-N-H or D-N-D angles of the ground and exited states are 106°47' and 120° (3) respectively, and does support the Franck-Condon Principle. It is shown that over 80% of the overlap between ground and exited state vibrational wave functions occurs for an H-N-H or D-N-D angle variation of 120° - 117°, indicating that most of the transitions occur when the molecule is nearly planar. Since the transitions occur for such a small range of Q, the corresponding variation of R[subscript e](Q) is probably small. The exited state fundamental frequencies [nu]'₁ and [nu]'₃ for ND₃ and [nu]'₁, [nu]'₃, and [nu]'₄ for NH₃ and NT₃ are theoretically determined using the experimental; NH₃ -- ND₃ isotope shift and the faint bands in ND tentatively assigned to 2[nu]'₄.Item 2̳52Cf plasma desorption mass spectrometry of metal clusters(Texas A&M University, 1991) Hughes, Janita MurielNot availableItem 2DBTOR: a toroidal geometry neutron diffusion code(Texas A&M University, 1990) Hrabal, Craig AnthonyNot available