Legacy Theses and Dissertations (1940-2009)
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This collection gathers digitized University of Houston theses and dissertations dating from 1940.
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Browsing Legacy Theses and Dissertations (1940-2009) by Department "Civil and Environmental Engineering, Department of"
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Item A comparative study of modern transient pipe-line techniques using ammonia as fluid medium(1970) Manikian, Victor; Hwang, Neddy H. C.; Graff, William J.; Dalton, CharlesThis thesis presents a comparative study of transient pipeline techniques using ammonia as a fluid medium. Physical properties and characteristics of the use of liquid ammonia in pipelines is first given, and then two basic methods of determining surge pressures are presented. Friction effect is very important in waterhammer analysis, especially in long pipelines where the frictional resistance is large in comparison to the surge pressure. Initially, solutions for short and long pipelines are analyzed using the graphical waterhammer method. Next, a method introduced by Ludwig & Johnson is used for the same short and long pipelines for comparison. This method may be used since conditions in normal pipeline surge problems allows the use of certain acceptable assumptions. Calculations and charts are included in this thesis to make it more useful and acceptable.Item A comparative study of two methods for displacements in a two-layer soil system(1980) Radhakrishnan, Arathil C.; O'Neill, Michael W.; Ghazzaly, Osman I.; Norman, Carl E.; Pincus, GeorgeThis thesis concerns a comparative study of displacement effects in a two-layer soil system using Mindlin's method and Plevako's method. The effect of both horizontal and vertical loads are investigated. The study is aimed at gaining insight into the behavior of pile group foundations. The material presented in this thesis consists of numerical computations to investigate the influence of an applied load on the added displacements in the soil at different points in the region of computational interest. A sufficient number of computations have been made in order to obtain some meaningful conclusions about the validity of the two methods. Even though analyses of the results show that no specific conclusions can be made about the range of applicability of each method, some quantitative conclusions have been arrived at based on the results. The influence of a stronger bottom layer is also investigated. Computations were made for different modular ratios of the two layers in order to validate the effect of a stronger bottom layer on the displacement characteristics of the top layer.Item A developmental study of a low cost housing system(1969) Wessels, Gary Dwayne; White, Ardis H.; Graff, William J.In this thesis, a low cost housing system was developed that will sell for under seven thousand dollars per dwelling. The housing system consists of factory produced and finished modular volume units that are combined at a housing site to create the dwelling unit. The goals and problems that low cost housing must attain and solve were discussed. Recent low cost housing trends were surveyed with respect to their construction method, materials used, and cost. Pre construction of modular volume units by a process similar to that used by the mobile home industry was found to be the most promising approach for a low cost housing system. The housing system as developed in this paper utilizes chemically prestressed concrete components for the construction of each modular volume unit. Each volume unit is assembled and finished on an assembly line, transported to a housing site, and attached to a prepared foundation at which time utilities are connected. In this study two volume units were combined to create a dwelling. Minimization of work done at the housing site, use of chemically prestressed concrete components to construct volume units, and an assembly line method for producing the volume units were the prime factors through which economy was achieved.Item A digital computer simulation of an automatically controlled complete mix activated sludge wastewater treatment plant using food : mass ratio control(1975) Simpson, Ronald Wayne; Matson, James A.; Rogers, Jerry R.; Bailey, James E.; Andrews, John F.With the activated sludge wastewater treatment process being as complicated as it is, a concerted effort is needed to develop an automatic control system which will respond effectively to variations in influent flow and concentration. Such a control system has been devised and evaluated in the research study reported herein. The primary control objective established for this study was to maintain a near constant food:mass ratio using return sludge flow as the control variable. Hydraulic retention time was allowed to vary from three to fifteen hours while the solids retention time was held constant at a value of eight days. A quasi food:mass ratio set point of 0.35 Kg/day/Kg was intended for steady state operation. Results of the study indicate that the previously mentioned control strategy allowed the food:mass ratio to vary from 0.1 to 0.7 Kg/day/Kg when the influent, flow and concentration were varied sinusoidally from plus to minus fifty percent of the steady state values. Effluent quality remained essentially constant; however, the final settling tank model indicated that the limiting solids flux was exceeded for periods up- to eight hours. This wouTd contribute to a degraded effluent should the condition last long enough for the sludge blanket to reach the effluent weir. A tighter control of the food:mass ratio was attempted by varying the reactor volume so as to maintain a constant hydraulic retention time of six hours. This control system modification reduced the food:mass ratio excursions significantly; however, no improvement was obtained in effluent quality. Finally, the performance of food:mass ratio control was compared with that of a more conventional control strategy—portional return sludge flow control. For the influent variations applied, the conventional control strategy gave as good a performance as foodfmass ratio control. Future studies should incorporate a much more detailed settler model which describes the effects of food:mass ratio changes on settling characteristics of the biological floc.Item A dynamic design procedure for fixed bed activated carbon adsorption of organics from concentrated industrial wastewater streams(1970) Lanford, Charles Edward, Jr.; Myrick, Henry Nugent; Seymore, Raymond B.; Bonar, Albert J.Future fresh water supply demands require a technological fix in fresh water supply practices if such are to be met. Two courses of research appear able to provide a broader fresh water supply base: desalinization of brine and reclamation of wastewater. The reclamation of domestic wastewater has been researched extensively, but the reclamation of concentrated industrial wastewater has not been investigated extensively. This research investigation explored the use of granular activated carbon adsorption to reclaim concentrated industrial wastewater. The Weber and Eckenfelder steady-state theories of fixed bed adsorber design were inapplicable to the analyses of data in which organic loading varied as a function of time. A finite differences approach was used to approximate the continuous design functions. This procedure eliminated several theoretical difficulties inherent in the Weber and Eckenfelder design theories. The dynamic theory developed was used to interpret the data from carbon adsorption columns on two live industrial wastewater streams and two synthetic wastewaters. The experiments confirmed the use of total organic carbon as loading parameters for design of fixed bed activated carbon adsorption column for multicomponent systems. The experimental data confirmed the usefulness of the design theory and the feasibility of granular activated carbon adsorption to reclaim concentrated industrial wastewaterItem A dynamic mode of the effects of groundwater recharge in the Clear Lake City-NASA area(1976) Klotz, David Wayne; Hwang, Neddy H. C.; Norman, Carl E.; Van Hoften, James D. A.High rates of groundwater withdrawal have resulted in serious declines in water levels in the aquifers of the Houston area. These declines have been instrumental in the high subsidence rates present in the area. The study involved an examination of artificial recharge to reverse the downward trend of the piezometric surface. A digital model was developed for the well system found in the Clear Lake City-NASA area. Included in the model were both existing wells and proposed recharge wells. The Theis equation was used as the basis for determining the effect of each well on the piezometric surface. A study was also conducted on amounts of water available for aquifer recharge. The results clearly show that a system of recharge wells would dramatically raise the piezometric surface in the study area. This increase in water levels can be accomplished using available water resources if properly treated. The effect of increased piezometric levels is discussed with respect to the expected effect on subsidence rates in the area.Item A dynamic model for predicting oxygen utilization in activated sludge processes(1980) Clifft, Ricky Conway; Andrews, John F.; Matson, Jack V.; Clifford, Dennis A.; Bailey, James E.; Lee, Kwang Y.; Pincus, GeorgeThe purpose of this research was to develop a dynamic model of activated sludge for investigating process oxygen requirements. The research effort was narrowed to consider only the metabolism of carbonaceous substrates with the main emphasis placed on modeling the biological reactor. Batch experiments were performed using a municipal wastewater to study the effects of particulate substrates, identify the most appropriate form of the model, and provide data for estimating the model parameters. Data was collected from an oxygen activated sludge pilot plant to test the equations developed for the gas-liquid interactions of a closed-reactor system. The experimental work was restricted to low sludge ages (less than 1 day). The model for the biological reactions distinguishes between particulate and soluble substrate metabolism and considers substrate storage by the floc. The batch experimental data was best described when soluble substrate was modeled as being concurrently stored by the floc and directly channeled into synthesis pathways. For most experiments, the best fit was obtaind when 70 to 80 percent of the soluble substrate was stored prior to metabolism. The particulate matter added in the batch experiments was found to have little or no affect on the total oxygen utilization rate for low sludge ages. Simulation of the oxygen activated sludge pilot plant indicated that the proposed model was capable of describing the transient data. The model was most applicable for predicting solids production, effluent carbonaceous TOD, and oxygen utilization. Predictions of gas phase composition and carbon-dioxide bicarbonate equilibrium were less accurate, but the general trend of predicted results appeared realistic. Most importantly, the model was capable of showing that the oxygen uptake rate was significantly damped and lagged substrate removal. Computer simulations were made to illustrate the effect of various design and operational factors on the oxygen utilization response to a diurnal substrate loading. Factors found to be most important included the type of substrate (soluble or particulate), the relative amounts of substrate channeled to storage products or directly into synthesis pathways, the reactor size and operational configuration, the type of separator operation, and the sludge age. When calibrated for a particular wastewater, the proposed model can be used to simulate both air and oxygen activated sludge plants. Computer simulations of the contact stabilization mode indicate that the proposed model would be useful in sizing the contact and stabilization reactors. The proposed model would also be useful in sizing aeration equipment. Only a model that considers substrate storage by the floc is capable of properly assessing the oxygen requirements for the stabilization reactor. Since oxygen requirements are usually damped and lag the influent organic load, the proposed model can provide an improved basis for sizing conventional aeration equipment, and also, for sizing the oxygen generating capacity for oxygen activated sludge. For plants not equipped with automatic dissolved oxygen control, control of aeration equipment may be improved by using the proposed model to derive a transfer function relating oxygen demand to influent flow. Also, it may be possible to utilize the model in conjunction with on-line, state-parameter estimation techniques for implementing real-time control strategies other than dissolved oxygen control.Item A laboratory data acquisition system utilizing the SDS-920 computer(1970) Rogers, Joseph E.; Nash, James M.; White, Ardis H.; Castellanos, Leopold J.The problem of measuring and recording static and dynamic transducer data has long been one of vital concern to experimental stress analysts. As most of the parameters that are measured vary with time, a requirement for continuous monitoring system is inevitable. This monitoring system is applied to the specimen under examination in such a manner as to yield the most valuable data. Additionally, some permanent record of the data is usually required or at least highly desirable. The initial problem encountered is supplemented by the time-consuming and often difficult task of reducing the recorded data to a meaningful form which yields some insight into the actual conditions being studied. [...]Item A laboratory scale approach to domestic solid wastes evaluation: monitoring of leachate(1970) Weber, Stephen J.; Myrick, Henry Nugent; Seymore, Raymond B.; Bonar, Albert J.The landfill is the oldest and still the most commonly used type of solid waste management. In spite of this, there have been few attempts to determine the extent of the threat posed to the purity of groundwater by landfilling municipal refuse. Whereas previous studies have used either very large samples or elaborate size reduction procedures to circumvent the problems presented by the heterogeneous nature of municipal solid waste, this thesis proposes a laboratory-scale method to investigate the quality of leachate. Water was percolated for forty-eight hours through three individual components of municipal waste in six-inch diameter columns. Empirical concentration versus time relationships were obtained for eight substances in the leachate. The usefulness of both the model and the method is demonstrated by using these data to predict the nature of the leachate from a mixture of the same three components percolated under the same conditions. Concurrently, it is shown that a single analysis, specific conductance, can be used to estimate the character of leachate with respect to five of the seven other parameters investigated.Item A method for improving performance of cooling ponds(1970) Wilcox, Charles M.; Myrick, Henry Nugent; Bonar, Albert J.; Elrod, John T.This thesis presents the results of a study of the efficiency of a cooling pond as related to temperature decreases, residence times and flow patterns. A literature review of cooling pond design principles and operational experiences was undertaken to more accurately relate the theoretical performance relationship of model and prototype. Laboratory experiments were conducted using a model of distorted scale with a flexible simulated levee system. Flow patterns and temperature decreases are correlated with various levee arrangements and the efficiency of the overall system is defined. The pond's capability as a wastewater treatment facility is also discussed. Conclusions are made on the effect of various factors influencing performance and overall efficiency of cooling ponds. Recommendations for further study of parameters relating to cooling pond design are also made.Item A real time study of pollutant gaseous exhaust stack emissions from a stationary gas turbine(1970) Wright, Howard S.; Myrick, Henry Nugent; Howell, John Reid; Bonar, Albert J.This thesis presents the results of a study of pollutant stack emissions from a gas turbine performed on a real time basis. Field studies were made at the site of a stationary industrial gas turbine utilizing natural gas fuel. Equipment for measuring stack pollutant emissions was obtained and located on the gas turbine site. Nitrogen oxides, carbon monoxide, hydrocarbons, aldehydes and sulfur dioxide were measured. An evaluation of the emissions related to gas turbine exhaust stack mass flow was made. A literature review of stack emissions from combustion sources was made. Results of the study are presented and discussed. Conclusions are made relating to the emissions measured and the equipment used. The results are related to the Houston area environment. Recommendations are made for further study and developmental activity.Item A review and evaluation of the theoretical determination of bearing capacity and settlement of footings(1973) Darnell, James Robert; Ghazzaly, Osman I.; Whitaker, Thomas N.; Bonar, Albert J.The most accepted theories on bearing capacity of foundations are summarized. Factors influencing bearing capacity, such as varying ground water level, sloping ground surface, and eccentric and inclined loading, are reviewed. In addition, the most accepted methods of computing short-term, or "immediate," settlement of foundations are briefly explained. The results of twenty-four load-settlement tests on model and full-scale footings, up to failure conditions, are gathered, and they are compared to the theoretically computed bearing capacities and settlements. A variety of combinations of footing sizes, shapes, and depths and soil types are represented. Evaluations and recommendations, based on the comparisons of the load and settlement test results with the computed values, are made concerning the bearing capacity theories and settlement computation methods.Item A review of moment distribution and its use in solving multi-story frames(1975) Bahramsoltani, Nahid; White, Ardis H.; Pincus, George; Whitaker, Thomas N.This thesis presents the history of the development of the moment distribution procedure and its impact on the solution of statically indeterminate beams and frames. The basic procedure, and both approximate and exact methods of analysis are presented, and then a series of nine single bay laterally loaded frames varying in height from two to ten stories is solved using the statics ratio method. The results of this work are then presented in tabular form from which certain significant observations and conclusions were obtained, most notable of which was that use of the statics ratio method is a rapid means of solving a multi-story frame. Furthermore, the pattern of final correct moments and the relationship between these and the product of the story height and shear, permits accurate prediction of the final correct moments for a frame without doing any moment distribution at all. The results are such that further investigation of the procedure is merited and recommended.Item A statistical evaluation of dynamic pile driving formulae in sand(1970) Syal, Raj Kumar; Ghazzaly, Osman I.; Bonar, Albert J.; Rankin, Fred W., Jr.; Dawkins, George S.Seven dynamic pile-driving formulae are used in this investigation to predict the capacity of 140 timber, precast concrete, and steel piles driven in, or to, sand. The piles were subdivided into different groups according to length, material, hammer, shape, and finally combined together. The computed capacities are compared statistically with the field test measured values. A linear relationship was assumed between the measured and computed pile capacities and the linear regression analysis was used to determine the slope and intercept of the regression line. Correlation coefficients and standard error of estimate were used as measures of the scatter about the regression line. Three approaches are employed in the statistical analysis to evaluate and compare the seven formulae. The approach based on developing a regression equation of the form 'Qa = BQc' represents a realistic model. The results indicate that, generally, Janbu's formula may be considered superior to the others in predicting pile capacity in sand. Hiley, Danish, Pacific Code, and Gates formulae appear to be reasonably reliable. However, Engineering News and Gow formulae are shown to be unsatisfactory, in general. Subdividing the data according to the pile material, length and shape, and according to the type of pile driving hammer used, affects the correlation between measured and computed pile capacity. The best formulae in each specific case are pointed out.Item A study of a horizontal flow vertical fixed phase biochemical wastewater treatment reactor(1968) Scher, Jacoby Allyn; Myrick, Henry Nugent; Seymore, Raymond B.; Bonar, Albert J.; Ghazzaly, Osman I.A bench-scale horizontal-flow, vertical fixed-phase aerobic biological process was studied with reference to support media, biological growth and film characteristics, oxygen requirements, and organic carbon removal for retention times of 0.1-12 day. 1° Butyl alcohol, 2° butyl alcohol, and methyl ethyl ketone were the components in the waste stream. Butyl alcohol, both normal and secondary, were consumed more rapidly, by the biological film than methyl ethyl ketone, although total removal was equal. This was demonstrated by direct aqueous injection gas chromatography. Biological treatment was found to be impractical below an organic waste concentration of 50-100 mg/1 Biochemical Oxygen Demand (BOD). Exchange of soluble biological intermediate and end products for organic wastewater components maintained approximately the same organic concentration in the process effluent. Oxygen requirements were found to be 400 m3 /kg-BOD loading for the diffuser at a depth of 4 inches. This corresponds well with a calculated value of 425 m3/kg-BOD, using the relationship that oxygen transfer rate is proportional to 0.7 exponent of the diffuser depth. The aerobic zone of the biological film was shown to have a maximum thickness of 2-3 mm. Polypropylene plastic mesh was shown to be a more satisfactory support media than cotton or nylon netting because it was relatively impervious to biological attack and was structurally superior.Item A study of an electrochemical process for the removal of phosphate, fluoride and ammonia from an industrial waste water(1971) Skaggs, Mack Rush; Myrick, Henry Nugent; Bonar, Albert J.; Poage, Scott T.Unfortunately, not until recently has any appreciable emphasis been placed on restricting inorganic contaminants from our fresh waters and estuaries. Since a large percentage of these inorganic contaminants, mainly phosphorus, fluoride and ammonia, found in waste water is not removed by conventional treatment processes, advanced waste water methods must be applied to the problem of removing these compounds. The principals of electrochemical removal of phosphate and ammonia have been applied to the treatment of domestic waste water. However, the application of this electrochemical principal for combined phosphate and fluoride removal from industrial waste water containing large quantities of both magnesium and calcium ions was not investigated. Thus, the purpose of this study will be to investigate the possibility of combined phosphate, fluoride, and ammonia nitrogen removal from contaminated sea water used for industrial cooling utilizing electrochemical treatment. The results of this study show that effluent phosphate and fluoride can be reduced to 0.6 mg/l and 8 mg/l respectively. However, the removal of ammonia nitrogen from the effluent was not significantly reduced by this electrochemical treatment. Also, the effluent phosphate and fluoride concentration is not dependent on the influent phosphate and fluoride concentration, provided sufficient calcium, magnesium or iron is available for complete precipitation, but is a function of either the coulombs or watt hours utilized during treatment.Item A study of creep in concrete(1967) Patel, Kantilal H.; Graff, William J.; Ghazzaly, Osman I.; White, Ardis H.; Paul, Arthur N.This volume presents a literature search on the subject of creep in concrete. Various theories are presented and discussed in detail. The factors which affect creep are critically reviewed. Results are presented on an experiment which was performed in a laboratory to study the behavior of creep in concrete. Test results are compared with those of other investigators. A new hypothesis is suggested for creep in concrete. This hypothesis seems logical as it combines both seepage and viscous theories. Recommendations are made for the further study of creep. An up-to-date annotated bibliography is presented on the subject of creep in concrete.Item A study of the autofrettage process(1967) Shaw, Genn Shi; White, Ardis H.; Blumberg, Randolph; Hwang, Neddy H. C.Over the past few decades, modern industrial processes have required higher and higher operating fluid pressures, and use of these high pressures have necessitated development of the auto-frettage procedure. This procedure consists of subjecting a thick-walled tube or vessel to such high internal pressure that plastic yielding in circumferential tension occurs on the inside for a significant portion of the wall thickness. When the auto-frettaging pressure is released, residual compressive circumferential stresses exist inside the wall (and for a significant portion of the wall thickness). These stresses are of opposite sign to those caused by subjection of the tube or vessel to subsequent working pressures. The inside circumferential stresses are then much lower than they would be had the tube or vessel never been autofrettaged. Use of the autofrettage procedure thus permits the use of higher pressures and insures a longer fatigue life than may be obtained by any other method. This thesis presents a thorough study of the theory and practice of the autofrettaging procedure, and also presents a comparison of the residual strains obtained with electric resistance strain gages during typical routine autofrettaging of high pressure tubes with the residual strains predicted by use of formulas derived for autofrettaging procedures.Item A study of the biodegradation of organic pollutants in a dilute aqueous system(1969) Hitchcock, Marie C.; Graves, Leon F.; Rankin, Fred W., Jr.; Bonar, Albert J.The biochemical oxygen demand test (BOD) and the chemical oxygen demand test (COD) have often been designated as tests to monitor bio degradation of organic pollutants in dilute aqueous systems. Specific limitations to oxygen demand measurements for these purposes have been found to be due to nonspecific identification of reaction mechanisms, metabolic by-products, and interfering components. Gas chromatography together with carbon analyses and dissolved oxygen measurements have proved to be effective analytical methods for defining the mechanisms, related metabolic by-products, and rates of biodegradation of organic pollutants in dilute aqueous systems. Gas chromatographic analysis of the biodegradation of secondary- butanol and tertiary butanol in the single dilution system made possible the detection of two intermediate metabolic by-products produced during biodegradation. One of the by-products was identified as 2-butanone; the other product, suspected to be acetoacetic acid, was not positively identified. During the growth phase of the heterogeneous mixed culture, 2 mg/1 of 2-butanone was produced for each mg/1 oxygen utilized and 0.6 mg/1 of biomass was produced. When the microbial population reached a maximum, biodegradation continued without further increase in biomass. The rate of oxygen utilization, during this stage of the reaction, was dependent upon the rate of metabolic by-product production. The formation of by-products ceased when the heterogeneous mixed culture entered the die-off phase of growth. At this point in the reaction, endogenous respiration determined the oxygen demand of the system.Item A study of the buckling of built-up columns(1968) Chiu, Chian-Li; Graff, William J.; Castellanos, Leopold J.; White, Ardis H.; Hwang, Neddy H. C.Many steel bridges, buildings, transmission and reception towers are constructed using built-up members. The buckling load of a built-up column is of interest to the designer because bending moments and stresses from the transverse loads are amplified when the compressive force approaches this critical load. This thesis presents an analytical study to evaluate the critical buckling load for several types of built-up prismatic members. The effect of shear deformations on the buckling strength is discussed in detail. An experimental investigation on the measurement of buckling strength of built-up members was made on small scale test columns. Test results are compared with those predicted by the theoretical analysis. The tests verify the predictions of column buckling strengths made using the theoretical basis presented in this paper.