Browsing by Subject "Instrumentation"
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Item Admittance measurement for assessment of cardiac hemodynamics in clinical and research applications(2012-05) Larson, Erik Rist; Pearce, John A., 1946-The admittance method is an important tool for the indirect determination of cardiac hemodynamics in animal research and has clinical potential as a hemodynamic monitor for implantable cardioverter-defibrillators (ICDs). Animal studies use a conductance catheter to determine left-ventricular (LV) volume, but ICDs must make use of existing pacing leads to perform an admittance measurement. This work aims to further the use of the admittance method by extending its use to multi-segment conductance catheters, determining parasitic circuit element's effects on electric property measurements, using biventricular pacing leads to determine cardiac hemodynamics, and analysis of spatial sensitivity using finite element models in various configurations. Experimental results show the admittance method can be used to determine LV stroke volume with biventricular pacing leads. Modeling results show removal of the muscle component focuses the measurement's spatial sensitivity towards the left-ventricular blood pool.Item Assessment of remaining fatigue performance of high mast illumination poles(2014-05) Belivanis, Konstantinos Victor; Helwig, Todd Aaron, 1965-Failures of high mast illumination poles (HMIP) around the US have raised the concerns of officials because of their location close to areas with important human activity. Previous research, conducted at the University of Texas proved that those failures were fatigue type failures and that cracking initiated at the shaft to baseplate connection, specifically at the bends of the shaft. However, no research has been conducted on the remaining fatigue life of poles after they have been in service. This thesis investigates the remaining fatigue life of a pole, removed from service after severe cracking has been observed on it, via laboratory testing. Moreover, nondestructive and destructive testing procedures were implemented to investigate the initiation and evolution of fatigue cracks. The results validated the procedures for the in-situ validation of the remaining fatigue life of those poles. Last, the destructive test results enhanced the arguments that initial cracking at the toe of the weld at the shaft to baseplate connection is a result of the galvanizing process.Item Development of environmental and oceanographic real-time assessment system for the near-shore environment(Texas A&M University, 2006-08-16) Ojo, Temitope O.The coupling of real-time measurements and numerical models will be important in overcoming the challenges in environmental and oceanographic assessments in surface waters. Continuous monitoring will take advantage of current state-of-the-art in sensor development, remote sensing technology. The numerical modeling tools available exist in many different forms and varying levels of complexity from depth integrated one-dimensional (1-D) models to full three-dimensional (3-D) models. Common to all are the constraints and forcing required in driving the models. These include hydrodynamic and barometric information, which are relatively difficult to obtain given the time scale of the bio-chemical and physical processes governing the fate and transport of the constituents of interest. This study is focused on the development of a framework that couples real-time measurements and numerical simulation for tracking constituents in surface waters. The parameterization of the mixing and turbulent diffusion impacts the formulation of the constituent-transport governing equations to the extent that the numerical model is being driven by near real-time observations of hydrodynamic data and the consequent evaluation of model coefficients. The effects of shear-augmented diffusion processes in shallow embayment and near-shore waters are investigated in order to develop algorithms for obtaining a shear diffusion coefficient, Ke from shear-current measurements and turbulent diffusion-coefficient, Kz measured by the auto-correlation function, Rτ of the velocity time-series. Typically, the diffusion coefficients are measured through tracer experiments as determined by the time rate of change of the variance of a growing patch (K = ?? dσ2 /dt), which introduces the concept of diffusion length-scale (or time-scale). In this study, the dye-tracer experiment was used, not so much in the context of evaluation of a diffusion coefficient, but within a modeling framework to validate a numerical scheme driven by real-time hydrodynamic observations. Overall, the effect of shear-currents in shallow wind-driven estuaries is studied using a prototype bay typical of the Texas Gulf-coast. A numerical model was developed and used in testing these hypotheses through a series of dye-tracer experiments under varying meteorological conditions.Item Development of Systems to Improve Cotton Module Shape(2011-10-21) Hardin, Robert GlenProperly constructed modules will prevent reduced lint value and increased ginning costs when significant rainfall occurs. Additionally, cotton producers often have difficulty finding adequate labor during harvest. These issues were addressed by developing a graphical operator feedback system, a biomass package measurement system, a powered tramper, and an autonomous module forming system. A system that provided feedback on the module shape by recording the position of the tramper and carriage was used to direct the operator to move cotton to appropriate locations. The system correctly predicted the height of 67% of data points. Use of the feedback system resulted in a 55% reduction in water collection area of the modules. The module builder operators indicated that the system was useful. The module builder feedback system is a simple, useful, and inexpensive tool that can have a rapid payback for producers. A powered tramper, with an auger to move cotton to the center of the module, was developed to replace the conventional tramper. The powered tramper operated automatically without affecting the operating speed or pressure of the tramper cylinder. During testing, the powered tramper was observed moving cotton to the center and crowned modules were produced. A biomass package measurement system was developed to record the height at multiple points on the top surface of modules. The system was found to produce repeatable measurements with an error of 5 cm. Data collected with this system did not indicate a difference in module shape when using the powered tramper; however, during these tests the powered tramper was turned off prematurely due to an improperly sized valve on the module builder. An automated module building system capable of both moving and tramping cotton was developed. This system utilized the feedback system sensors and photoelectric sensors to determine the location of cotton in the builder. A wireless display allowed the boll buggy operator to control the automatic system. The automatic system constructed modules with 64% less water collection area in an average time of 37.4 min. Cotton producers indicated that the system was easy to use and of significant value in reducing labor requirements.Item Development of tandem time-of-flight instrumentation for the examination of prompt photodissociation of peptides using 193-nm radiation(Texas A&M University, 2006-04-12) Morgan, Joseph WilliamThe design and incorporation of a decelerating/accelerating cell into a reflectron time-of-flight mass spectrometer is described for the examination of promptly-formed photodissociation products of peptide ions. The analytical utility of prompt 193-nm photodissociation was investigated for model peptides that resemble tryptic digest products, as well as for two sets of homologous peptides. The first of these sets include bradykinin, several bradykinin fragments, and two bradykinin mutants with substituted amino acids. Fragment ion spectra of [M + H]+, [M + Na]+, and [M + Cu]+ were collected for each of these peptides. The second set of homologous peptides has the sequence XVGVAZG, where variable amino acid X was either arginine, histidine, or lysine, and amino acid Z was either proline, serine, or glycine. Photofragment ion spectra obtained using the new mass spectrometer are compared to results of high energy collision induced dissociation (CID) acquired on a high performance commercial instrument. The advantages and disadvantages of prompt photodissociation relative to CID are discussed, as well as the advantages of photodissociation using the modified instrument geometry versus that of the post-source decay focusing method.Item Development of the West Texas Mesonet and supporting instrumentation(2005-05) Weinbeck, Stephen W.; Peterson, Richard E.; Smith, Douglas; Chang, Chia-Bo; Mulligan, KevinIn the last several years, the Wind Science and Engineering Center (WISE) at Texas Tech University has acquired a collection of new atmospheric sensing platforms. The most important of these is the West Texas Mesonet, an array of 40 automated surface observation systems. The purpose of the Mesonet is the acquisition of high spatial and temporal measurements of the atmosphere in West Texas. This provides an order of magnitude increase in the spatial resolution of atmospheric phenomena. The primary focus of WISE research is to understand the surface layer effects of high wind events. The addition of the mesonet allows for substantially better understanding of the resolution of the environment in which these damaging windstorms form and propagate. Despite the improvement of the resolution of the atmosphere, many important physical processes in the storm environment cannot be resolved directly through mesonet observations. In order to provide the high spatial resolution that is necessary, additional observations need to be utilized in conjunction with the Mesonet. Short portable towers and mobile mesonet vehicles allow researchers to capture very high spatial and temporal scales in the atmosphere. To supplement the additional data density at the surface , there is a new WISE boundary layer tower at the Reese technology center; co-located there are a boundary layer wind profiler and Doppler Sodar, as well as the nearby KLBB Doppler radar operated by the National Weather Service is located nearby. Together, these sensing platforms provide observational data of dramatically improved resolution for the Researchers at WISE as well as others. In order to highlight the advantages at the greater density, observations of the damaging wind events of 11 June 2000 and 30 May 2001 will be presented.Item Development of the West Texas mesonet and supporting instrumentation(Texas Tech University, 2005-05) Weinbeck, Stephen W.; Peterson, Richard E.; Smith, Douglas; Chang, Chia-Bo; Mulligan, KevinIn the last several years, the Wind Science and Engineering Center (WISE) at Texas Tech University has acquired a collection of new atmospheric sensing platforms. The most important of these is the West Texas Mesonet, an array of 40 automated surface observation systems. The purpose of the Mesonet is the acquisition of high spatial and temporal measurements of the atmosphere in West Texas. This provides an order of magnitude increase in the spatial resolution of atmospheric phenomena. The primary focus of WISE research is to understand the surface layer effects of high wind events. The addition of the mesonet allows for substantially better understanding of the resolution of the environment in which these damaging windstorms form and propagate. Despite the improvement of the resolution of the atmosphere, many important physical processes in the storm environment cannot be resolved directly through mesonet observations. In order to provide the high spatial resolution that is necessary, additional observations need to be utilized in conjunction with the Mesonet. Short portable towers and mobile mesonet vehicles allow researchers to capture very high spatial and temporal scales in the atmosphere. To supplement the additional data density at the surface , there is a new WISE boundary layer tower at the Reese technology center; co-located there are a boundary layer wind profiler and Doppler Sodar, as well as the nearby KLBB Doppler radar operated by the National Weather Service is located nearby. Together, these sensing platforms provide observational data of dramatically improved resolution for the Researchers at WISE as well as others. In order to highlight the advantages at the greater density, observations of the damaging wind events of 11 June 2000 and 30 May 2001 will be presented.Item Instrumentation and Evaluation of a Pilot Scale Fluidized Bed Biomass Gasification System(2009-12-04) Maglinao, Amado LA pilot scale fluidized bed biomass gasifier developed at Texas A&M University in College Station, Texas was instrumented with thermocouples, pressure transducers and motor controllers for monitoring gasification temperature and pressure, air flow and biomass feeding rates. A process control program was also developed and employed for easier measurement and control. The gasifier was then evaluated in the gasification of sorghum, cotton gin trash (CGT) and manure and predicting the slagging and fouling tendencies of CGT and manure. The expected start-up time, operating temperature and desired fluidization were achieved without any trouble in the instrumented gasifier. The air flow rate was maintained at 1.99 kg/min and the fuel flow rate at 0.95 kg/min. The process control program considerably facilitated its operation which can now be remotely done. The gasification of sorghum, CGT and manure showed that they contained high amounts of volatile component matter and comparable yields of hydrogen, carbon monoxide and methane. Manure showed higher ash content while sorghum yielded lower amount of hydrogen. Their heating values and gas yields did not vary but were considered low ranging from only 4.09 to 4.19 MJ/m3 and from 1.8 to 2.5 m3/kg, respectively. The production of hydrogen and gas calorific values were significantly affected by biomass type but not by the operating temperature. The high values of the alkali index and base-to acid ratio indicated fouling and slagging tendencies of manure and CGT during gasification. The compressive strength profile of pelleted CGT and manure ash showed that the melting (or eutectic point) of these feedstock were around 800 degrees C for CGT and 600 degrees C for manure. Scanning electron microscopy (SEM) images showed relatively uniform bonding behavior and structure of the manure ash while CGT showed agglomeration in its structure as the temperature increased. The instrumentation of the fluidized bed gasifier and employing a process control program made its operation more convenient and safe. Further evaluation showed its application in quantifying the gasification products and predicting the slagging and fouling tendencies of selected biomass. With further development, a full automation of the operation of the gasifier may soon be realized.Item The Development of Measurement Techniques to Identify and Characterize Dusts and Ice Nuclei in the Atmosphere(2014-01-15) Glen, AndrewMineral dusts and ice crystals directly influence the Earth's radiative budget through radiative scattering and absorption. The interaction of spherical particles on the radiative budget are well known, however mineral dusts and ice crystals are generally non-spherical leading to large uncertainties in the radiative impacts of these particles. In addition, atmospheric dust has the ability to act as an Ice Nuclei (IN) aiding in the formation of ice crystals in the atmosphere through four well known nucleation mechanisms. The work presented here discusses new instrumentation and methods to measure and identify both the optical scattering properties and ice nucleation properties of atmospherically relevant dusts. The Texas A&M University Continuous Flow Diffusion Chamber (CFDC) was constructed and characterized in the laboratory using a known effective IN, silver iodide. This instrument was then deployed in the Arctic as part of the Indirect Semi-Direct Aerosol Campaign (ISDAC) where it measured the concentration of potential IN under atmospheric conditions. The results of which, showed the Arctic has higher particle concentrations during the spring compared to data collected in the fall during other field projects. In addition, extreme nucleation events were observed with average IN concentrations as high as 100 L^(-1). The optical scattering properties of atmospherically relevant dusts were measured using a prototype instrument, the Cloud Aerosol Spectrometer with Polarization (CASPOL) under laboratory conditions. The data collected using this instrument allowed the classification of 13 atmospherically relevant dusts into 3 distinct groups based on the optical scattering properties. This instrument was then upgraded by the manufacturer and used to measure the optical scattering properties of both atmospherically relevant dusts and ice crystals generated using the CFDC with the previously examined dusts as potential IN. The results show the dusts can still be categorized into 3 distinct groups and can be differentiated from generated ice crystals. These results provide methodologies for differentiating atmospheric dust from ice crystals in the atmosphere using remote sensing instrumentation.