Browsing by Subject "performance"
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Item A causal model of linkages among strategy, structure, and performance using directed acyclic graphs: A manufacturing subset of Fortune 500 industrials 1990-1998(Texas A&M University, 2004-09-30) Chong, HogunThis research explored the causal relationships among strategies, corporate structure, and performance of the largest U.S. non-financial firms using Directed Acyclic Graphs (DAGs). Corporate strategies and structure have been analyzed as major variables to influence corporate performance in management and organizational studies. However, their causal relationships in terms of which variables are leaders and followers, as well as the choices of variables to configure them, are controversial. Finding of causal relationships among strategic variables, structural variables, and corporate performance is beneficial to researchers as well as corporate mangers. It provides guidance to researchers how to build a model in order to measure influences from one variable to the other, lowering the risk of drawing spurious conclusions. It also provides managers a prospect of how certain important variables would change by making a certain strategic decision. Literatures from agency theory, transactional cost economics, and traditional strategic management perspective are used to suggest variables essential to analyze corporate performance. This study includes size and multi-organizational ownership hierarchy as variables to configure corporate structure. The variables to configure corporate strategies are unrelated and related diversification, ownership by institutional investors, debt, investment in R&D, and investment in advertisement. The study finds that most of the variables classified as corporate strategy and corporate structure variables are either direct or indirect causes of corporate accounting performance. Generally, results supports the relational model: corporate structure? corporate strategy? corporate performance. Ownership hierarchy structure, unrelated diversification, advertising expenses, and R&D intensity have direct causal influences on corporate accounting performance. Size and related diversification affected corporate accounting performance indirectly, both through ownership hierarchy structure. Theoretical causal relationships from agency theory are less supported than those from transaction cost economics and traditional strategic management perspective. Further my study suggests that, in general, good corporate performance in 1990s was mainly achieved by internal expansion through investment in R&D and advertisement, rather than external expansion of firms through unrelated diversification, related diversification, and expansion of ownership hierarchy.Item A methodology for performance and compatibility evaluation of an all-digital substation protection system(Texas A&M University, 2007-04-25) Portillo Urdaneta, LeviA power system protection system consists, at least, of an instrument trans- former, a protective device (relay), and a circuit breaker. Conventional instrument transformers bring currents and voltages from power network levels to much lower scaled-down replicas that serve as input signals to protective relays. The relay's function is to measure input signals (or a relationship among them in some cases) and compare them to defined operating characteristic thresholds (relay settings) to quickly decide whether to operate associated circuit breaker(s). Existing protection systems within a substation are based on a hardwired interface between instrument transformers and protective relays. Recent development of electronic instrument transformers and the spread of digital relays allow the development of an all-digital protection system, in which the traditional analog interface has been replaced with a digital signal connected to digital relays through a digital communication link (process bus). Due to their design, conventional instrument transformers introduce distortions to the current and voltage signal replicas. These distortions may cause protective relays to misoperate. On the other hand, non-conventional instrument transformers promise distortion-free replicas, which, in turn, should translate into better relay performance. Replacing hardwired signals with a communication bus also reduces the significant cost associated with copper wiring. An all-digital system should provide compatibility and interoperability so that different electronic instrument transformers can be connected to different digital relays (under a multi-vendor connection) Since the novel all-digital system has never been implemented and/or tested in practice so far, its superior performance needs to be evaluated. This thesis proposes a methodology for performance and compatibility evaluation of an all-digital protection system through application testing. The approach defines the performance indices and compatibility indices as well as the evaluation methodology.Item Assessing Urban Residential Irrigation Performance Using a Water Budget Approach(2014-12-16) Lewis, Alan ChristopherWasting water by excessive irrigation of urban residential landscapes is a ubiquitous problem. By reducing irrigation in excess of plant water needs, homeowners and cities save substantial quantities water. Although water utilities can use a variety of approaches to encourage customers to reduce their consumption, some residences may use water more efficiently than others. By understanding patterns of irrigation performance among customers, water utilities can develop more economical approaches for encouraging water conservation. Irrigation performance can be assessed by comparing outdoor water use with a landscape water budget. This requires an accurate estimate of irrigated landscape area, which can be difficult to obtain for citywide datasets. A bivariate approach using tax appraisal information is proposed, which can be applied in any county. Irrigation performance was assessed for 5,565 single-family residences by examining their conformance to monthly water budgets. Nonconformance was defined as outdoor water use exceeding the monthly budget volume. Large lots were found to overwater by significantly greater volumes than smaller lots. However, lots with smaller landscape areas tended to overwater more frequently and apply higher volumes per unit area. These findings suggest new management options for addressing consistently wasteful water use and improving efficiency.Item Behavioral Performance and Evolution of Feeding Modes in Odontocetes(2010-07-14) Kane, Emily A.Vertebrate evolution has resulted in a diversity of feeding mechanisms. Cetaceans are secondarily derived tetrapods that have returned to a marine habitat. As a result, they display feeding modes that have converged with more basal aquatic vertebrates, but display a diversity of new solutions and adaptations. To begin to explore the diversity of feeding adaptations among odontocetes, kinematics of feeding modes and feeding adaptations for belugas (Delphinapterus leucas), Pacific white-sided dolphins (Lagenorhynchus obliquidens), and long-finned pilot whales (Globicephala melas) were characterized. In addition, direct measurements of intraoral pressure were collected to determine maximum suction performance. Characters from these analyses were combined with data for other odontocetes, and were mapped onto a phylogeny of Odontoceti to begin to explore where changes in feeding modes took place. Feeding modes were diverse in belugas, Pacific white-sided dolphins, and pilot whales and included suction, ram, and a combination of both. In general, four phases were observed: (I) preparatory, (II) jaw opening, (III) gular depression, and (IV) jaw closing. Suction was a large component of the prey capture method in belugas and subambient pressures in excess of 100 kPa were generated. Belugas were also capable of lateral lip gape occlusion and anterior lip pursing to form a small anterior aperture. Pacific whitesided dolphins relied on ram to capture prey. However, some degree of pursing and resultant subambient pressure was observed that was likely used to compensate for high ram speeds or for prey manipulation and transport to the esophagus. Pilot whales were more similar to belugas in kinematics, but maintained high approach velocities and did not generate significant suction pressures; suction and ram were used in combination. Belugas and pilot whales appeared to employ hyolingual depression as a primary suction generation mechanism, whereas Pacific white-sided dolphins relied on fast jaw opening. Ancestral state reconstructions indicated that suction feeding capability evolved independently at least six times within Odontoceti. These results indicate the diversity of feeding behaviors in odontocetes and provide directives for future studies on the diversity of feeding in secondarily aquatic mammals.Item Evaluation of Exogenous Enzymes Targeting Non-starch Polysaccharides in Reduced Energy Diets on Broiler Growth Performance and Processing Parameters(2013-12-04) Klein, Joseph ThomasMultiple experiments were conducted to investigate the inclusion of a cocktail NSPase and ?-mannanase, separately and in combination, in reduced energy diets on broiler growth performance and processing yield. Each experiment contained a positive control (PC), negative control (NC) diet (-132 kcal/kg AME), and the inclusion of enzymes in the NC to evaluate enzyme effectiveness. The reduction in energy negatively impacted performance and processing parameters in all experiments. The inclusion of NSPase negated the negative effects of energy reduction in experiment 1. Experiment 2 evaluated increased pelleting temperature on NSPase activity. Body weight (BW) was increased (P<0.05) with the inclusion of NSPase pelleted at 80, 85, and 90 C throughout the experiment compared to NC; however, the treatment pelleted at 80 C outperformed the other NSPase pelleted treatments. The inclusion of NSPase pelleted at 80 C reduced (P<0.05) feed conversion ratio (FCR) compared to the NC throughout the experiment. At the conclusion of the trial, NSPase inclusion pelleted at 85 and 90 C yielded FCR similar to PC. The experimental design of experiment 3 and 4 included five dietary treatments including a PC, NC, NC supplemented with ?-mannanase, NSPase, and ?-mannanase/NSPase. Performance parameters were evaluated on d 14, 28, 42, and 47 and a subset of broilers were processed on day 48. Increases (P<0.05) in BW were observed with the inclusion of NSPase and ?-mannanase/ NSPase on day 14 and with all treatment groups on day 28. An additive effect was observed with reduced FCR through day 28 with the combination of ?-mannanase/ NSPase. In experiment 4, performance was evaluated on days 14, 27, 35, and 41 and carcass yields determined on day 42. Increases in day 14 BW were observed with the inclusion of the NSPase alone and ?-mannanase/NSPase to reach a similar weight as the PC. Inclusion of ?-mannanase/NSPase increased (P<0.05) BW compared to the NC. Inclusion of the NSPase reduced (P<0.05) cumulative FCR through 41 days of age. Inclusion of ?-mannanase/NSPase resulted in reduced (P<0.05) FCR in the finisher phase and cumulatively throughout the trial to levels of the PC. The combination of ?-mannanase/NSPase did increase (P<0.05) WOG weight similar to observations in BW. These data confirm that enzyme supplementation in low energy diets improve performance and indicate that additive effects of a combination of enzymes could potentially be a cost saving strategy for producers.Item Evaluation of Performance in Yearling Crossbred Steers following Bovine Viral Diarrhea Virus Challenge(2013-10-31) Runyan, Chase AnthonyThis study investigated the effects of vaccine type, sire, day, threshold rectal temperature status, and their potential interactions on growth, daily feed intake and daily feed bunk frequency in response to a standardized Bovine Viral Diarrhea Virus (BVDV) challenge. Yearling, F2 and F3 Nellore-Angus steers (n = 380) from the Texas A&M McGregor Genomics herd were utilized over 4 years, and were stratified by sire over three vaccine groups of modified-live (MLV), killed (KV), and non-vaccinated (NON). Vaccines were used in accordance to label directions, and MLV steers were separated from KV and NON steers for 7 to 10 days to prevent transmission of viral particles. All steers were intranasally challenged with BVDV type 1b strain CA0401186A on day 0 of each year. Clinical signs of illness and feeding behavior data were collected daily, while rectal temperature and weight records were collected at days 0, 3, 7, 10, 14, 28, and 42 post-vaccination. The influence of sire was a significant source of variation as both a main effect or as an interaction term for all response variables analyzed. Vaccine type was a significant source of variation as components of interaction terms; lower (P < 0.05) mean rectal temperature was seen in MLV as compared to KV and NON steers. Variation from sire and vaccine type interaction suggests the potential of matching genetic profiles and vaccine protocols to achieve optimum levels of production measures. Daily feed intake and daily bunk visit frequency tended to decrease through day 7, but these traits should be interpreted separately due to the effects of sire and sire by vaccine type interactions. Higher number of bunk visits did not explain levels of intake within some sire groups and vaccine groups. Lung tissue disruption based on color scores of 3 or 4, on 5-point scale was present in more than 65% of cattle that did not have elevated rectal temperature above 40oC, the threshold basis for provision of antibiotic treatment. Interactions involving sire, vaccine type or rectal temperature status with other factors in this trial illustrates complexity regarding interpretation of cattle health impacts on production traits.Item Evaluation of traits associated with bucking bull performance and behavior(2009-05-15) Romero, Natasha ElizabethVideo and industry data were used to assess the inter-relationships of aggression, delivery, coat color, year of birth, number of outs, buckoff percent and score in rodeo bulls. An evaluation of laterality based on observations of how the individual animals were loaded into chutes at 11 bull riding events showed 63% left-handed delivery and 37% right-handed delivery across all observations (n = 525). There was a similar distribution for aggressiveness (based on whether or not the bull charged after the rider dismounted) with 64% of bulls being non-aggressive and 36% of bulls being aggressive. Significant linear relationships existed between score and number of outs and score and buckoff percentage indicating that experience impacted performance. The correlation between number of outs and buckoff percentage was low to moderate (0.06 to 0.30), depending upon the subset of data evaluated. The r-square value for the analysis of score among all bulls was 0.14; however, the r-square value in the subset of bulls with known sires with more than one son was 0.68 when sire was included in the model. Similar increases in r-square values were observed for 2006 average score, career average score, buckoff percentage, and career buckoff percentage, indicating important genetic influences on these traits and/or their component traits. Investigations into the relationship between performance and aggression may help bucking stock producers improve the selection criteria they use. The current trend within the industry is for several breeders to breed ?hot? or flighty, nervous cattle to achieve higher performing offspring. Given that there was no association between aggression and score based on chi-square test, aggression may be removed from the criteria for using certain animals for breeding purposes. Based on results from this work, if bucking stock breeders want to make genetic changes in these traits, documentation of pedigree information is vital.Item Generalized Correlations to Estimate Oil Recovery and Pore Volumes Injected in Waterflooding Projects(2012-02-14) Espinel Diaz, Arnaldo LeopoldoWhen estimating a waterflood performance and ultimate recovery, practitioners usually prepare a plot of log of water-oil ratio vs. cumulative production or recovery factor and extrapolate the linear section of the curve to a pre-established economic limit of water production. Following this practice, engineers take the risk of overestimating oil production and/or underestimating water production if the economic limit is optimistic. Engineers would be able to avoid that risk if they knew where the linear portion of the curve finishes. We called this linear portion the "straight-line zone" of simply SLZ. In this research, we studied that ?straight-line zone? and determined its boundaries (beginning and end) numerically using mathematics rules. We developed a new procedure and empirical correlations to predict oil recovery factor at any water/oil ratio. The approach uses the fundamental concepts of fluid displacement under Buckley-Leverett fractional flow theory, reservoir simulation, and statistical analysis from multivariate linear regression. We used commercial spreadsheet software, the Statistical Analysis Software, a commercial numerical reservoir simulator, and Visual Basic Application software. We determined generalized correlations to determine the beginning, end, slope, and intercept of this line as a function of rock and fluid properties, such as endpoints of relative permeability curves, connate water saturation, residual oil saturation, mobility ratio, and the Dykstra-Parsons coefficient. Characterizing the SLZ allows us to estimate the corresponding recovery factor and pore volumes injected at any water-oil ratio through the length of the SLZ . The SLZ is always present in the plot of log of water-oil ratio vs. cumulative production or recovery factor, and its properties can be predicted. Results were correlated in terms of the Dykstra-Parsons coefficient and mobility ratio. Using our correlations, practitioners can estimate the end of the SLZ without the risk of overestimating reserves and underestimating water production. Our procedure is also a helpful tool for forecasting and diagnosing waterfloods when a detailed reservoir simulation model is not available.Item Host Plant Influences on Performance and Haplotype Diversity of Dalbulus maidis, a Specialist Herbivore of Zea(2012-12-06) Davila-Flores, AmandaIn one study, a suite of plants from the maize genus Zea L. (Poaceae) and the specialist herbivore Dalbulus maidis (DeLong and Wolcott, 1923) (Hemiptera: Cicadellidae) were used to test the hypotheses that anti-herbivore defenses are affected by plant life-history evolution and human intervention through domestication and breeding for high yield. The suite of Zea host plants included one Mexican commercial hybrid maize Zea mays ssp. mays L., a landrace variety of maize, two populations of Balsas teosinte (Zea mays ssp. parviglumis Iltis & Doebley), and perennial teosinte (Z. diploperennis Iltis, Doebley & Guzman). This suite of host plants includes three Transitions evident within the genus Zea: life history form perennial to annual life cycle evident between perennial teosinte and Balsas teosinte, domestication transition from wild annual to domesticated annual evident between Balsas teosinte and landrace maize, and; breeding transition from landrace cultivar to a hybrid cultivar. The transitions were correlated with differences in plant defenses, as indicated by corn leafhopper performance. Results showed a performance gradient, suggesting a pattern in which plant defense is stronger in perennial than annual plants, Balsas teosinte than landrace maize, and in landraces than in hybrid maize. Furthermore, results suggested that domesticated maize would be the least defended, most suitable host for corn leafhopper. In a second study, haplotype diversity was assessed to address structuring and interconnectedness among samples of corn leafhopper collected in the southwestern region of Mexico to address microevolution. The geographic focus of the study was maintained within an area encompassing the presumed centers of radiation of Dalbulus and its host genus Zea, and of maize domestication. Samples were complemented with samples of corn leafhopper sequences available at GenBank. Results revealed seven haplotypes from three host plants within Zea: perennial teosinte, Balsas teosinte, and maize. Furthermore, genetic differentiation was present and haplotype diversity appears to correlate with differences in genetic structure between perennial teosinte and maize. One haplotype was found to be present throughout all sites, which appears to parallel the spread of maize cultivation. As maize cultivation spread beyond its area of domestication, corn leafhoppers colonized perennial teosinte, further suggesting that subsequent decreases in maize cultivation in perennial teosinte habitat created a refuge where perennial teosinte- adapted haplotypes could persist. Altogether, my research suggests that the combination of historical expansion of maize cultivation expansion and the weaker anti-herbivore defenses associated within maize domestication appears to have favored genotypes particularly adapted for exploiting maize.Item Impacts of Castration and Docking Method on Lamb Stress and PerformanceBodenchuk, Leigh Ann .; Salisbury, Michael W; Scott, Cody B; Runyan, Chase A; Osterhout, John JThe objectives of this study were to determine which method of castration and docking causes more stress to lambs and subsequent effects on performance. For this study 60 crossbred lambs, 31 females and 29 males, were assigned to one of two treatment groups. Female lambs were docked while male lambs were castrated. Lambs were docked or castrated with either an All-in-One tool or by elastrator rubber band. Ewe lambs docked with an elastrator band were more restless than lambs docked with an All-in-One (p < 0.01). There were no differences in mean 93 day weight between ewe treatments (p = 0.93). Male lambs castrated with an elastrator band vocalized more (p = 0.03) and were more restless than lambs castrated with an All-in-One (p = 0.05). Mean 93 day weight was affected by treatment with banded males weighing more than All-in-One castrated males (p = 0.03). Results suggest that castration method can affect performance while docking method does not.Item Improving workplace performance, morale, and retention(Law Enforcement Management Institute of Texas (LEMIT), 2011) Sanderson, KevinItem Performance analysis and modeling of GYRO(Texas A&M University, 2006-10-30) Lively, Charles Wesley, IIIEfficient execution of scientific applications requires an understanding of how system features impact the performance of the application. Performance models provide significant insight into the performance relationships between an application and the system used for execution. In particular, models can be used to predict the relative performance of different systems used to execute an application. Recently, a significant effort has been devoted to gaining a more detailed understanding of the performance characteristics of a fusion reaction application, GYRO. GYRO is a plasma-physics application used to gain a better understanding of the interaction of ions and electrons in fusion reactions. In this thesis, we use the well-known Prophesy system to analyze and model the performance of GYRO across various supercomputer platforms. Using processor partitioning, we determine that utilizing the smallest number of processors per node is the most effective processor configuration for executing the application. Further, we explore trends in kernel coupling values across platforms to understand how kernels of GYRO interact. In this work, experiments are conducted on the supercomputers Seaborg and Jacquard at the DOE National Energy Research Scientific Computing Center and the supercomputers DataStar P655 and P690 at the San Diego Supercomputing Center. Across all four platforms, our results show that utilizing one processor per node (ppn) yields better performance than full or half ppn usage. Our experimental results also show that using kernel coupling to model and predict the performance of GYRO is more accurate than summation. On average, kernel coupling provides for prediction estimates that have less than a 7% error. The performance relationship between kernel coupling values and the sharing of information throughout the GYRO application is explored by understanding the global communication within the application and data locality.Item Performance of Polymer Coatings Under Forming Conditions(2012-02-14) Purohit, ZalakPrepainted metal sheets being environment friendly and cost effective as compared to postpainted metal sheets, are widely used in construction, packaging, transportation and automotive industries. One of the key requirements for prepainted coatings is to retain its surface quality and properties during forming process. During forming process, major surface damage occurs when the coated sheet is bent and un-bent around the die corner. To reduce surface damage of coatings, proper control of the parameters during forming and detail study of the surface conditions is required. In the present study, influence of forming parameters such as die radius, lubrication and specimen material are investigated. The influence of these parameters on friction, surface damage and properties of polymer coatings are evaluated. Experiment set-up is built to conduct bending under tension test. This test gives a better way to evaluate coating performance, as it closely simulates the die region of real forming process and considers bending effects. Experimental results show increase in friction and surface damage with decrease in die radius. Moreover, with decrease in die radius hardness of the coating decreases and strain in the specimen increases. Lubrication has some effect on coefficient of friction, but the influence is not as significant as that of die radius. This is attributed to the fact that, the polymer coating itself acts as a solid lubricant in the test. Material effect was studied, polypropylene coating being the softer material compared to PVDF coating shows more surface damage in the form of scratches. Numerical simulations were performed using Finite Element Analysis package (FEA) Abaqus. A 2D model was built, exploiting the plane strain condition for bending under tension test. Numerical simulations indicate that maximum contact pressure and von Mises stress are concentrated at the beginning of the drawing edge. Apart from the location, the value of contact pressure was higher for smaller die radius. Thus, experiments help in studying the effect of forming parameters on coating performance and numerical simulations provide more insight into the critical areas where stresses are high. Numerical simulations also provide a scope to study the effect of material and geometric parameters on performance of coatings without running experiments.Item Profiles in Courage: Practicing and Performing at Musical Open Mics and Scenes(2010-10-12) Aldredge, Marcus DavidThis dissertation explores the social patterns and cultural layers of musical "open mics" in New York City. The study uses a qualitative approach which includes methods such as ethnography, in-depth interviewing, historical and discourse analyses focusing on open mics and the popular musicians who attend and perform them. Open mics, short for "open microphones," are public events that allow musicians to perform songs without a pre-planned, formal booking with a club or venue. Owing a historical and discursive connection to the folk hootenannies and jazz jam sessions of the past, these events have proliferated and spread considerably across the United States since the 1990s since their development, by name, in the late 1970s. Open mics not only reflect a do-it-yourself and participatory cultural ethos manifested with other recent expressive cultural activities, but also demonstrate a growing interstitial "musical third place" residing between private practicing and public performance. Musical open mics as musical third places provide musicians and singer/songwriters to network with other musicians, practice new musical compositions and play when other performance opportunities are not readily available. It provides a means for musicians to "hone their craft" in terms of performance methods and also construct musical identities in the almost exclusive company of other working singer/songwriters. This "backstage region" is thus framed and keyed by the musicians onto a continuum between two theoretical poles: performance practicing and practicing performance. Performance practicing as defined in this study frames a more performance-oriented display for musicians in locations called "closed open mics" or COMs. These settings, also residing on a theoretical continuum are socially more exclusive in terms of performance types, the aesthetic careers of the performers, the genres represented and the sociological makeup of the setting participants in general. OOMs or "open open mics," on the other hand, usually have a more fluid, diverse sociological composition of musical performers, performance types, and musical genres played and represented in these mainly weekly events. Closed open mics align into more homogeneous, isomorphic settings comprising "local open mic scenes" and open open mics remain more heterogeneous, socially inclusive, and unsettled as "pre-scenes."Item Queer Utopian Performance at Texas A&M University(2012-07-16) Sayre, DanaThrough a combination of personal interviews and participant-observation in three field sites ? the Tim Miller workshop and performance of October 2010 and the student organizations Cepheid Variable and the GLBT Aggies ? I argue that manifestations of utopian desire and performance circulate within and among marginalized groups on the Texas A&M University campus, undermining the heteronormative and monolithic utopia the university attempts to present. I participated in each night of rehearsal during the Tim Miller workshop, as well as the creation and performance of my own solo autobiographical monologue as a part of the ensemble. My participant-observation in Cepheid Variable and the GLBT Aggies was concurrent, consisting of attendance at both weekly organizational meetings and outside events sponsored by the organizations over two years. I argue that the Tim Miller workshop and performance is best understood by examining the intersection of queer intimacy, utopia, and performance. I argue that processes of connection, sharing, and mutual transformation allowed it to function as an example of queer utopian performance qua performance at Texas A&M. I explore the links between the ?nerd,? ?queer,? and ?family? identities of Cepheid Variable, arguing that the intersection of these identity-markers and the performance practices which reinforce them enable Cepheid Variable to create a utopian space on the Texas A&M campus for those students who do not fit traditional notions of Aggie identity. I explore two Cepheid performance practices: noise-making and storytelling, arguing that they construct, support, and interweave each element of Cepheid identity, allowing the organization to perpetuate and reaffirm its utopian and counterpublic statuses at Texas A&M. I explore what the GLBT Aggies claims to provide in theory, juxtaposed with what it actually accomplishes in practice. I examine a moment of crisis the LGBTQ community at Texas A&M faced in spring 2011. I argue that the utopia the GLBTA promises remains unfulfilled because the marginalization of the LGBTQ community at large leaves diversity within that community unaddressed. I conclude that utopian communities persist if able to adapt, and that the strength of the intimacy built into queer utopias in particular sustains them through time.Item Seismic fragility and retrofitting for a reinforced concrete flat-slab structure(Texas A&M University, 2004-09-30) Bai, Jong-WhaThe effectiveness of seismic retrofitting applied to enhance seismic performance was assessed for a five-story reinforced concrete (RC) flat-slab building structure in the central United States. In addition to this, an assessment of seismic fragility that relates the probability of exceeding a performance level to the earthquake intensity was conducted. The response of the structure was predicted using nonlinear static and dynamic analyses with synthetic ground motion records for the central U.S. region. In addition, two analytical approaches for nonlinear response analysis were compared. FEMA 356 (ASCE 2000) criteria were used to evaluate the seismic performance of the case study building. Two approaches of FEMA 356 were used for seismic evaluation: global-level and member-level using three performance levels (Immediate Occupancy, Life Safety and Collapse Prevention). In addition to these limit states, punching shear drift limits were also considered to establish an upper bound drift capacity limit for collapse prevention. Based on the seismic evaluation results, three possible retrofit techniques were applied to improve the seismic performance of the structure, including addition of shear walls, addition of RC column jackets, and confinement of the column plastic hinge zones using externally bonded steel plates. Finally, fragility relationships were developed for the existing and retrofitted structure using several performance levels. Fragility curves for the retrofitted structure were compared with those for the unretrofitted structure. For various performance levels to assess the fragility curves, FEMA global drift limits were compared with the drift limits based on the FEMA member-level criteria. In addition to this, performance levels which were based on additional quantitative limits were also considered and compared with FEMA drift limits.Item The impacts on broiler performance and yield by removing antibiotic growth promoters and an evaluation of potential alternatives(2009-05-15) Bray, Joey LynnThree experiments were conducted to evaluate the impacts of removing antibiotic growth promoters (AGP) on broiler performance and yield and to evaluate alternative products as potential replacements. In experiment one, approximately 552,000 broilers were reared in four solid-wall, tunnel ventilated houses that were divided into two paired-house facilities, each assigned one of two dietary treatments. The treated group received basal diets containing salinomycin (SAL), roxarsone (ROX) and AGP, while the control group received the same diets without ROX and AGP. Removal of ROX and AGP had no affect on average body weight and feed efficiency, while livability was significantly affected negatively by the removal of ROX and AGP. Tender, wing, drum and percentage of total white meat showed significant improvements in yield during the study, while all other parts were not affected by removal of ROX and AGP. In experiment two, an investigation was conducted to evaluate the effects on performance from feeding Bacillus subtilis spores (Gallipro?, Chr Hansen A/S, Denmark), as a direct-fed microbial additive, to commercial broiler chickens. Birds were divided among two paired-house facilities. The treatment group received basal diets supplemented with B. subtilis spores, while the control group was fed the same basal diets containing an AGP. Feed conversion ratio was significantly lower for the treatment group, while average body weight, coccidiosis lesion scores, and footpad scores were not affected by the treatments. In experiment three, 6,000 broiler chickens were equally divided among four treatment groups and reared to 49 d to determine the effectiveness mannan oligosaccharides (MOS, Bio-Mos?, Alltech, Nicholasville, Kentucky, USA) as an alternative for an AGP program and MOS plus Natustat? (NAT, Alltech, Nicholasville, Kentucky, USA) as an alternative to an enteric health program (AGP+anticoccidial drug). Average body weight for the control (CON) and antibiotic (ANT) groups was significantly different from the MOS+NAT group, but not the MOS group. Carcass front half, carcass hind half, frame and skin yields were improved for all treatments when compared to the MOS+NAT group. Conversely, percent total white meat yield was improved with the inclusion of MOS when compared to the ANT group. The findings of this research suggest that the removal of AGP from the diets of commercial broiler chickens does not affect the performance and yield of the birds over a one year production period. Furthermore, B. subtilis spores and mannan oligosaccharides provide acceptable alternatives to an AGP program.