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Dissertations / Theses on the topic 'Chemical engineering – Equipment and supplies'
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1
Aryana, Shahla. "Advanced operation and optimisation of an industrial ethylene oxide plant." Phd thesis, Faculty of Engineering and Information Technologies, 2009. http://hdl.handle.net/2123/5402.
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Reyes, Salvador Byron Fernando. "DEVELOPMENT OF A HIGH-PRESSURE, HIGH-TEMPERATURE SUPERHEATED STEAM SYSTEM (WATER TREATMENT, VAPORIZER, THERMAL DESIGN, MODELING)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275460.
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Jośī, Dilīpa. "REAL-TIME DIGITAL CONTROL FOR BIOMASS LIQUEFACTION SYSTEM (HIGH PRESSURE, TEMPERATURE, MICROPROCESSOR, AUTOCLAVE)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275423.
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Theruviparambil, Augustine Antony. "Reliability improvement of chemical process plant." Thesis, Queensland University of Technology, 1999. https://eprints.qut.edu.au/36094/1/36094_Theruviparambil_1999.pdf.
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When equipment acceptance procedures are ill-defined, or even neglected, customers are exposed to risks that may result in costly equipment failures. Use of well-defined acceptance procedures in an Equipment Acceptance Procedures Manual (EAPM) can be instrumental in reducing these risks. A case study was chosen to demonstrate how acceptance procedures could be instrumental in mitigating equipment failures before the equipment is introduced
into service. The acceptance procedures address design, manufacture and vibration audits of a refinery cooling tower fan gearbox. It is shown how recurrent failures of cooling tower fan gearboxes may have been avoided by
improvements to procurement procedures. During the process of the lubrication audit, it became evident that no information was available to estimate the gearbox power losses for gears rotating with their axes in the vertical lane. Hence, a simple experiment was designed to determine and evaluate the gearbox hydrodynamic power loss. The results of this experiment are compared with the data available for gears rotating about the horizontal axis and a relationship factor was determined
to evaluate the total hydrodynamic power losses quantitatively of the gearbox under consideration.
5
Gray, Michael Dean. "An experimental investigation of the anomalous behavior of underwater acoustic volume displacement sensors." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/16796.
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Christensen, David Paul. "Three-dimensional audio processor." Scholarly Commons, 1997. https://scholarlycommons.pacific.edu/uop_etds/2315.
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The thesis presents the principles, design, implementation, and test results of a prototype three-dimensional audio processor based upon the Analog Devices EZ-KIT Lite digital signal processing development platform. The three-dimensional audio processor simulates a virtual sound source that is free to move in three-dimensional space using a monaural audio source for input, a personal computer and mouse for source position control, and six loudspeakers arranged in a Cartesian array for output. Source distance, direction, and speed cues are produced by the processor using the Inverse Square Law, time delay, loudspeaker mixing, and sampling rate conversion by third-order polynomial interpolation. Test results confirm the performance of the three-dimensional audio processor.
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Chirara, Karim. "Laboratory tests of corrugated plastic drainage tubing with small holes in different soils." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64035.
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Mutshekwa, Ndivhuho. "Effect of time-based hot air drying method on chemical composition of jatropha zeyheir tea." Thesis, University of Limpopo, 2017. http://hdl.handle.net/10386/1914.
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Thesis (M. Sc. (Agriculture)) --University of Limpopo, 2017Tea is one of the most popular consumed beverages in the world, which has beneficial properties such as anti-oxidization, anti-carcinoma and preventing arteriosclerosis. The major essential components of catechins present in tea leaves, includes epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), gallocatechin (GC) and catechin (C). Influence of time-based hot air drying method on chemical composition of the Jatropha zeyheri Sond, widely consumed in rural communities of Zebediela (Khureng village), Limpopo Province, South Africa, was investigated. Four treatments, namely; 0, 24, 48, and 72 hours, were arranged in completely randomised design (CRD), replicated five times. The study demonstrated that drying significantly increased total phenolic content, total antioxidant capacity and tannin content. It also demonstrated that drying significantly increased minerals elements; Mg, K, P, S, Al, Co, Mn, Si and Zn content and decreased Na, Ca and Ni and Zn quantities. Sodium-potassium ratio was very low across drying periods. Drying time did not significantly influence proximate chemicals; energy, protein, carbohydrates, ash and fibre content. Moisture and fat were significantly increased by drying period. Results of the study suggested that time-based hot air drying method improved the chemical composition of J. zeyheri, which has the potential of enhancing nutrition in marginal rural communities of Limpopo Province.
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Lorenzen, Bruce Robert 1959. "DESIGN AND DEVELOPMENT OF A SUBSURFACE TRICKLE LATERAL EXTRACTION DEVICE." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276473.
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A tractor mounted three-point hitch implement was developed to extract and collect subsurface trickle irrigation laterals from the soil. Power to the implement was supplied by the tractor hydraulic system to the three-point hitch and two remote hydraulic circuits. In operation, the implement loosened the soil around the lateral, extracted the tubing from the soil, wound it on a reel assembly, and then dropped the roll of tubing at the end of the row. Draft power requirements averaged 14.5 kW (19.4 hp) and hydraulic power averaged 0.56 kW (.75 hp) when the one row implement was operated at 7.2 km/h (4.5 mph). Field capacity of the one row implement averaged 0.19 ha/hr (.47 ac/hr) when operated in 100 m (328 ft) long rows.
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Scott, Stephen Bryce. "An ergonomic analysis of commercially available exercise equipment : implications for resistance training and clinical rehabilitation." Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1016367.
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This study examined the often contrived advertising claims of the manufacturers of variable resistance isotonic machinery. Specifically, the study sought to ascertain whether certain equipment was compatible with musculo-skeletal and perceptual needs and limitations of the human user: that is, to determine whether presently installed eccentric cams, which provide the variable resistance, matched the users force curves. The format of this research was in the ergonomic tradition in which empirical research is not necessarily the primary avenue. Consequently the inter-disciplinary nature of ergonomics required small-scale laboratory- simulation experiments to be conducted in a diverse range of disciplines such as physiology, psychology and biomechanics. It was found that on all five pieces of variable resistance machinery analysed, a mismatch between the force curves and the eccentric cams exist. The cams were redesigned accordingly. The metabolic cost of performing fixed-rate isoinertial lifts was moderate. The psychophysical analysis revealed that perceptual responses indicated that the work was classified as 'light' and only at 30% stress levels do local cues begin to dominate. Based on these findings it was concluded that manufacturers advertising claims in the instances analysed were not well-founded and that variable resistance isotonic machinery should only be used to develop muscular strength and endurance, and do not effectively serve as weight-loss devices.
11
Meunier, Pierre. "Psychophysical assessment of load-carrying in internal and external-frame backpacks." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-05022009-040630/.
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Maran, Juliano. "Study of truck allocation and truck dispatching problems in open pit mines." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45807.
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In recent years, fierce competition, rising production costs and depressed prices for mineral products, have forced mining companies to find ways to improve efficiency and lower production costs. Given the fact that loading and hauling operations account for up to 60 % of the total costs in surface mining, the optimization and control of these operations can provide substantial reductions in the costs.
Assignment of truck to shovels has been traditionally performed by fixed truck allocation and by truck dispatching. Several operations research and simulation techniques, which can be used to solve problems concerning surface mining operations, are discussed. The types of problems addressed are: how to allocate trucks to loading equipment, how to evaluate the performance of an existing operation, and how to predict the performance of a future system.
For truck allocation, operations research methods such as: dynamic programming, integer programming, and heuristic algorithms are discussed. These methods are used mainly for decision making purposes. Queuing theory techniques, also analyzed, are used mainly for evaluation purposes.
Master of Science
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Horylev, Matthew James. "The effects of hearing protection on speech discrimination in differing noise spectra." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45808.
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This research project was aimed at investigation of speech communication issues in industrial noise environments where workers utilize hearing protection devices (HPDs).
A controlled empirical study was conducted to determine the effects of several independent variables on speech reception and discrimination including: l). subject's hearing configuration (unoccluded or earplug, earcap, earmuff-occluded), 2). ambient noise intensity level (60, 83 dBA), 3). ambient noise spectral type (low, white approximation, high frequency), 4). speaker's voice level (63 or 65 dBA in 60 dBA noise, 82 or 88 dBA in 83 dBA noise), and 5). subject's hearing level (normal hearing, slight loss, or moderate loss) used as a blocking variable. Isophonemic word discrimination, with male-voiced word lists presented through loudspeakers in an anechoic field, served as the experimental task. Twenty-three males and twenty-two females participated in the experiment and a mixed-factors, partial hierarchical design was used for data collection. Analysis of variance and Newman-Keuls multiple-range tests were applied to the data.
All main effects, with the exception of hearing level blocks, were significant, in addition to several interactions. These are discussed in detail and depicted graphically. One fundamental finding was that none of the hearing protection devices degraded speech discrimination (in comparison to an unoccluded condition) in the 83 dBA ambient noise level. In fact, the most protective HPD significantly enhanced speech discrimination in the high noise level. In the low ambient noise level, there was some reduction in discrimination due to the wearing of an HPD, but this effect is not of concern because HPDs are not needed at low ambient levels for protection purposes. From the results, it appears that properly selected HPDs can be expected to at least maintain speech discrimination levels (equivalent to unoccluded levels) in moderately-high intensity industrial noises of varied spectral characteristics.
Master of Science
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Lambert, Shawn P. (Shawn Patrick). "The use of decision trees to empower production technicians to troubleshoot routine process and equipment problems." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10946.
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Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1996 .Includes bibliographical references (p. 111).
by Shawn P. Lambert.
M.S.
15
Kashi, Mohsen Gholam-Reza. "A performance analysis of the hi-plan structural apparatus." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/50031.
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Visual experience is a powerful pedagogic tool. Extensive use of experimental studies prior to design and construction has made conceptualization of complex structures possible. Experiments on reduced-scale structures and specimens are also vital tools for teaching structural mechanics. As such, the Department of Civil Engineering at Virginia Tech has acquired a new apparatus for use as an educational demonstration tool in the area of structural mechanics. This work presents the results of a detailed study on the performance of this device as related to its accuracy and operation.
To fulfill such objectives, two structural models (a continuous beam and a portal frame) were extensively tested under several loading and support configurations. The models were analysed using STRUDL as well as a computer program developed by the author. The comparison of the results (deformations) obtained in the two phases of the study have indicated that the apparatus is reasonably accurate to meet the requirements of a structural teaching model and adapting to a variety of structural models.Master of Science
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Peng, Kevin S. M. Massachusetts Institute of Technology. "An equipment selection methodology for continuous manufacturing of small-molecule drugs." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122266.
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This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: S.M., Massachusetts Institute of Technology, Department of Chemical Engineering, 2019, In conjunction with the Leaders for Global Operations Program at MIT
Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2019, In conjunction with the Leaders for Global Operations Program at MIT
Cataloged from student-submitted PDF version of thesis. "June 2019."
Includes bibliographical references (pages 87-89).
Flexible, modular, continuous manufacturing small-scale plants (MCSPs) for small-molecule drugs have been recognized as potential safe and economical solutions for pharmaceutical manufacturing. However, among the variety of equipment technologies required for an MCSP platform, there are only a few technologies that have publicly available methodologies for equipment selection. In this study, a new method and tool for computer-assisted equipment selection was developed, which use key engineering correlations and design criteria to match off-the-shelf equipment with the synthesis processes of interest. Furthermore, the tool allows simultaneous equipment selection for multiple synthesis processes to allow the identification of the most flexible MCSP assets. The long-term goal of this tool is to encompass the entire span of technologies that could be used in an MCSP skid and to serve as a communal storage location for vendor-available equipment information to facilitate collaboration and design of a mainstream continuous manufacturing (CM) system. This methodology was applied to equipment selection for the continuous manufacturing of an actual Amgen small-molecule drug substance (API) as a case study. The results from this study showed that the new tool can improve the speed at which equipment is selected and can aid the process developer in decision-making for choosing the most suitable CM asset.
by Kevin Peng.
S.M.
M.B.A.
S.M. Massachusetts Institute of Technology, Department of Chemical Engineering
M.B.A. Massachusetts Institute of Technology, Sloan School of Management
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Peterson, Zachariah Marcus. "Physical and Electrical Characterization of Triethanolamine Based Sensors for NO₂ Detection and the Influence of Humidity on Sensing Response." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/418.
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Triethanolamine (TEA) is a semiconducting polymer which exhibits a resistance change when exposed to various gases. The polymer also exhibits a number of reactions with nitrogen dioxide, with the reaction products being heavily dependent on the presence or absence of water vapor. Previous studies have attempted the incorporation of a TEA-carbon nanoparticle composite as the active sensing layer in a chemresistive sensor for detection of NO₂. The incorporation of carbon nanoparticles in the polymer nanocomposite was thought to amplify the sensor's response. There are a number of chemical reactions that can occur between TEA and NO₂, with the reaction products being heavily dependent on the presence and amount of water vapor in the environment. Because of this influence, it becomes necessary to know to what degree the presence of water vapor interferes with the sensing response. In this work we show that the sensor exhibits a reversible resistance change as background humidity changes. This sensitivity to humidity changes is so large that it renders undetectable any resistance change that could be caused by the reaction of TEA with NO₂. Furthermore, we show that the presence of low levels of NO₂ do not interfere with adsorption of water vapor. The detection mechanism is based on measuring resistance changes in the TEA film due to the adsorption/desorption of water vapor. The sensing response can be described by Langmuir adsorption by using a site-based model for the polymer film resistance. Breakdown of the polymer film over time due to continuous adsorption of water vapor, as well as photodegradation of the polymer film, will be discussed. SEM images will also be presented showing growth of crystallites on the electrode walls, as well as experimental results demonstrating degradation of the sensing film during sensor operation.
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Schoevers, Jacobus Engelbertus. "Low blood oxygen saturation quantification in human arterial and venous circulation." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21460.
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Thesis (MScIng)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation in low saturation and perfusion scenarios. This limits the application of pulse oximetry in patients su ering from peripheral vascular a ictions. A novel pulse oximetry system is presented in this study which proposes solutions to these low saturation and perfusion issues. The presented system was designed to overcome the low perfusion issues by inducing an arti cial pulse in the detected photoplethysmograph. A novel arterio-venous hypothesis was formulated to extract arterial and venous saturation data from this arti cial photoplethysmograph using arterial-to-venous compliance ratios. Sensor wavelengths were selected to provide high and low saturation accuracy, followed by an in vitro sensor calibration procedure. System performance was validated by means of in vivo human studies. In vivo results indicate good accuracy for high saturation, with limited accuracy in low saturation scenarios. The arterio-venous hypothesis was validated, indicating that venous saturation information can be extracted from the arti cial PPG. Although inconclusive, results indicate that the proposed system might be able to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios with recommended hardware and calibration modi cations. It is recommended that further studies into the presented system's performance are conducted.
AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes. 'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding. Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die sisteem getoets is deur middel van 'n in vivo validasie prosedure. Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek kan word. Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe sal egter aan die sisteem aangebring moet word in terme van hardeware en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.
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Baker, Henry Thomas. "A Study of Walkway Safety and Evaluation of Tribological Test Equipment." UNF Digital Commons, 2014. https://digitalcommons.unf.edu/etd/484.
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A walkway tribometer measures the coefficient of friction between flooring material and a test foot. The value of the coefficient of friction is an indicator as to whether the flooring surface is slippery and has a propensity to cause slip and falls. This study determined that one style of tribometer, an XL Tribometer, mimics the heel-to-floor interaction of the human heel strike. High speed video footage revealed that the test foot strikes the surface and rotates so that full engagement occurs before sliding thus mimicking the affect of a human ankle. The test foot accelerates forward as would be expected during a human slip event. The manufacturer’s reported impact speed of 11 in/s, when set to the operating pressure of 25psi, was found to be much lower than measured speeds of three calibrated tribometers. Three XL tribometers were tested and provided a range of impact speeds from 17.4 to 22.7 in/s (n=540) when set to the operating pressure of 25 psi. The pressure setting was found to have a significant effect on the impact speed while the mast angle had an insignificant affect. A review of human walking studies revealed a range of pedestrian heel impact speeds on the order of 19.4 to 45.3 in/s during normal human ambulation activities. These tribometers fell on the low side of this speed range. A sensitivity study showed that the measured value of the coefficient of friction tends to decrease with a higher impact speed. This COF decrease was on the order of 0.02 and below the machine resolution and considered inconsequential within the walkway safety community.
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Fitzgerald, Nicholas B. "The Small Volume Autonomous Water Sampler (SVAWS): An Innovative, Cost- Effective, Adaptable Protocol." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1533.
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As of 2007, U.S. pesticide use stood at 1.1 billion pounds with 80% of all usage in agriculture. Such realities pose a potentially dangerous threat to our surface water bodies. This research provides a detailed analysis of the design, operation and field testing of a prototype water sampler, the Small Volume Autonomous Water Sampler (SVAWS). The research includes a discussion of the design and construction of the SVAWS. Seven USGS employees operated the SVAWS in a number of different states and conditions in order to collect samples for pesticide analysis. Field-testing outcomes of the SVAWS were measured through a Participant Survey Request and a Likert-Scale Assessment.
Overall, survey data proved the SVAWS to be an effective device for collecting water samples in different locations and conditions. Users also understood the SVAWS has significant potential for applications other than pesticide studies. While feedback did show a number of alterations or modifications could improve the design, the device proved to be effective across many of its goals, from valid water sampling to reducing costs of sample acquisition. Recommendations for future research include these and other avenues of research. A conclusion addresses the potential future of the SVAWS with respect to water sampling applications.
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Hedges, Mitchell Lawrence. "An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1020615.
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This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
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Thakare, Aditya. "A Study of Microwave curing of Underfill using Open and Closed microwave ovens." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2246.
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As the demand for microprocessors is increasing with more and more consumers using integrated circuits in their daily life, the demand on the industry is increasing to ramp up production.
In order to speed up the manufacturing processes, new and novel approaches are trying to change certain aspects of it. Microwaves have been tried as an alternative to conventional ovens in the curing of the polymers used as underfills and encapsulants in integrated circuits packages. Microwaves however being electromagnetic waves have non uniform energy distribution in different settings, causing burning or incomplete cure of polymers.
In this study, we compare the two main types of microwaves proposed to perform the task of curing the polymers. To limit the study and obtain comparable results, both microwaves were limited to propagate in a single mode, TE10. The first is a closed microwave cavity using air as the propagation medium, and the second is an open microwave oven with a PTFE cavity that uses an evanescent field to provide energy.
The open air cavity was studied with different orientations of a substrate placed inside it so as to find the best case scenario in the curing process. This scenario was then compared with the best case scenario found for a sample cured in an evanescent field.
This comparison yielded results showing an advantage of the open microwave in maximum field present, thus leading to higher localized energy absorption and temperatures in the substrate, however this case also lead to a higher temperature gradient. The substrate cured in the closed microwave has a lower temperature gradient, but also a lower maximum field which leads to slower cure.
In the TE10 mode therefore, a closed microwave has an overall advantage as the heating process is only slightly slower than that of an open cavity, but the temperature gradient in this case is significantly lower.
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Bredenkamp, Adolf Friedrich Ludwig. "Development and control of a 3-axis stabilised platform." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/380.
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Conradie, P. A. (Petrus Alwyn). "The development of a dynamic engine-testing facility." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52509.
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Thesis (MScEng.)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: The last two decades have seen many changes within the automotive industry. Many advances have been made in the design, research and development of the internal combustion engine and technological progress made in the integrated-circuit and computer industry has resulted in the availability of reliable low-cost electronic components. These components have, over time, been incorporated into the very hearts of engines, thereby allowing for the accurate control of engine functions and processes to an extent that was previously impossible. Parallel to these developments is the growing concern for the environment and the realisation that resources are being consumed at ever-increasing rates. This has placed vehicle manufacturers under continual pressure to optimise their engines, not only for fuel efficiency, but also to reduce harmful emissions while continuing to deliver better performance and drivability characteristics. At the same time, engine testing equipment and facilities have had to keep abreast with these advances and this has required the development of more sophisticated testing facilities. One such facility is the dynamic engine test-bed. Among other features, this facility has the ability to subject test-bed mounted engines to loads similar to what would be experienced in a vehicle on the road. This approach allows for the optimisation of engine components and performance under more realistic conditions, yielding results far superior to those obtainable using more conventional steady-state testing and development procedures. This document discusses the development of such a dynamic engine test-bed at the Centre for Automotive Engineering at the University of Stellenbosch. The project was initiated by conducting a literature survey to establish the current state of technology in the field. The dynamic test-bed was developed around an existing direct-current electric motor and industrial speed controller configured in a regenerative manner. This setup enabled the unit to both absorb and deliver power, essential for the simulation of vehicle dynamics. Great care was taken to ensure that signals obtained from the test-bed were accurate and useful for further computer manipulation. Anti-aliasing filters were designed and manufactured to guarantee that signals could not be misinterpreted due to sampling effects. A computer-implemented vehicle model was developed to simulate, in real-time, vehicle response to torque developed by the engine on the test stand. The model included a manual transmission, clutch and a rigid drive-shaft. Driver input (accelerator, brake, clutch and gear selection) was by means of a set of pedals and hand-held gear selector switches. Various vehicle speed control strategies were investigated and recommendations made regarding their possible future implementation. System evaluation was accomplished by the simulated acceleration of a large truck. The simulations indicated that repeatable results could be obtained from the system. The system was also found to be adequately sensitive to reflect the effect of subtle changes made to engine parameters on vehicle acceleration. It was concluded that the dynamic engine test-bed did indeed offer the capability to conduct research and testing not previously available in South Africa. Finally, recommendations were made for the future improvement and expansion of the system's performance and capabilities.
AFRIKAANSE OPSOMMING: Die laaste twee dekades het baie veranderinge in die outomobiel industrie megebring. Groot vooruitgang is gemaak in die ontwerp, navorsing en ontwikkeling van die binnebrand enjin, terwyl tegnologiese vooruitgang in die geïntegreerde-stroombaan en rekenaar industrië betroubare elektroniese komponente teen lae koste beskikbaar gemaak het. Hierdie komponente is mettertyd in enjins geïnkorporeer en het die akkurate beheer van enjin funksies en prosesse moontlik gemaak. Saam met hierdie ontwikkeling, is daar toenemende kommer oor die omgewing en 'n bewuswording dat hulpbronne verbruik word teen 'n groeinde tempo. Hierdie feite plaas voertuig vervaardigers onder volgehoude druk om enjins te optimeer vir brandstof doeltreffendheid, maar ook om skadelike emissies te bekamp terwyl beter werksverrigting en bestuurbaarheid vereis word. Enjin toetstoerusting en fasiliteite moes terselfdetyd met hierdie vooruitgang byhou en het die ontwikkeling van meer gesofistikeerde toetsfasiliteite vereis. Een sodanige fasiliteit is die dinamiese enjin toetsbank. Een van die kenmerke van hierdie fasiliteit is dat dit toetsbank-gemonteerde enjins kan onderwerp aan 'n las soortgelyk as wat ondervind sou word in 'n voertuig op die pad. Hierdie benadering stel ingenieurs in staat om enjin komponente en werksverrigting te optimeer onder meer realistiese kondisies en lewer resultate van 'n baie hoër gehalte as wat verkry kan word deur gebruik te maak van meer konvensionele gestadigde-toestand toets- en ontwikkelings-prosedures. Hierdie dokument bespreek die ontwikkeling van so 'n dinamiese enjin toetsbank by die Sentrum vir Automobielingenieurswese aan die Universiteit van Stellenbosch. Die projek is geïnisieer deur 'n literatuurstudie te doen om die huidige stand van tegnologie in die gebied vas te stel. Die dinamiese enjintoetsbank is ontwikkel rondom 'n bestaande gelykstroom-motor en industriële spoed beheerder wat in 'n regeneratiewe konfigurasie opgestel is. Hierdie opstelling het die absorpsie en lewering van drywing moontlik gemaak, 'n vereiste vir die simulasie van voertuig dinamika. Baie tyd is gespandeer om te verseker dat seine afkomstig van die toetsbank akkuraat en bruikbaar was vir verdere rekenaar manipulasie. Anti-aliaseringsfilters is ontwerp en vervaardig om te verseker dat seine nie verkeerd geïnterpreteer kon word as gevolg van diskritiserings effekte nie. 'n Rekenaar ge-implementeerde voertuigmodel is ontwikkel om 'n voertuig se reaksie op draairnoment ontwikkel deur die enjin op die toetsbank intyds te simuleer. Die model het 'n handrat transmissie, koppelaar en starre dryf-as ingesluit. Bestuurder intree (vernellingspedaal, rem, koppelaar en rat seleksie) is bewerkstellig deur middel van 'n stel pedale en 'n hand geoperateurde rat skakelaar. Verskeie voertuig spoed-beheerders is ondersoek en aanbevelings is gemaak aangaande die toekomstige implementering daarvan. Die sisteem is geëvalueer deur die versnellingsimulasie van 'n groot vragmotor. Die simulasies het daarop gedui dat herhaalbare resultate van die sisteem verkry kon word. Daar is ook bevind dat die sisteem sensitief genoeg was om subtiele veranderinge aan enjinparameters in die resultate te weerspieël. Die gevolgtrekking is gemaak dat die dinamiese enjin toetsbank inderdaad die vermoëns gebied het om ontwikkeling en toetswerk te doen wat nie voorheen in Suid-Afrika moontlik was nie. Voorstelle is laastens gemaak aangaande die toekomstige verbetering en uitbreiding van die sisteem se vermoëns.
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Smit, Andre. "Development of a telerobotic test bench system for small-field-of-operation bilateral applications with 3D visual and haptic (kinaesthetic) feedback." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86516.
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Thesis (MScEng) Stellenbosch University, 2014ENGLISH ABSTRACT: Teleoperation as a field has seen much change since its inception in the early 1940s with Dr. Raymond Goertz producing the first teleoperation system for manipulating radioactive materials. With advances in core and supporting technologies, the systems have grown in complexity and capability, allowing users to perform tasks anywhere in the world irrespective of physical distance. The feasibility of such systems has increased as the drive for use of telepresence robots, exploration robots as in space exploration, search and rescue robots and military systems such as UAVs and UGVs gain popularity. This prompted the development of a proof of concept modular, user centred telerobotic system. The current project is the second iteration in the development process. Teleoperation and more specifically telerobotic systems pose a challenge for many system developers. This may be a result of complexity or the wide assortment of knowledge areas that developers must master in order to deliver the final system. Developers have to balance system usability, user requirements, technical design and performance requirements. Several developmental process models are considered in context of Engineering Management (EM). A larger Systems Engineering developmental process is used, with focus on the primary and supportive EM components. The author used a hybrid developmental model that is user focussed in its approach, the User-Centred Systems Design (UCSD) methodology was adopted as the primary model for application within the two distinct developmental categories. The first category hardware and system integration utilised the UCSD model as is. The second - Software development - relied on the use of agile models, rapid application development (RAD) and extreme programming (XP) were discussed with XP being chosen as it could easily incorporate UCSD principles in its development process. Hardware systems development consisted of mechanical design of end-effectors, configuration management and design, as well as haptic and visual feedback systems design for the overall physical system. Also included is the physical interface design of the input (master) cell. Further software development was broken into, three sections, the first and most important was the graphical user interface, haptic control system with kinematic model and video feedback control. The force following and matching characteristics of the system were tested and were found to show an improvement over the previous implementation. The force magnitude error at steady state was reduced by 10%. While there was a dramatic improvement in system response, the rise time was reduced by a factor 10. The system did however show a decrease in angular accuracy, which was attributed to control system limitations. Further human-factor analysis experiments were conducted to test the system in two typical use-case scenarios. The first was a planar experiment and the second a 3D placement task. The factors of interest identified were field-of-view, feedback vision mode, and input modality. Heuristic performance indicators such as time-to-completion and number of collisions for a given task were measured. System performance was only showed significant improvement when used with haptic control. This shows that the research into haptic control systems will prove to be valuable in producing usable systems. The vision factor analysis failed to yield significant results, although they were useful in the qualitative systems analysis. The feedback from post-experimentation questionnaires showed that users prefer the Point of View as a field of view and 2D viewing over 3D viewing, while the haptic input modality was preferred. The results from the technical verification process can be used in conjunction with insights gained from user preference and human-factor analysis to provide guidance for future telerobotic systems development at Stellenbosch University.
AFRIKAANSE OPSOMMING: Telewerksverigting as ’n gebied het al vele veranderinge ondergaan vandat die eerste stelsels deur Dr. Raymond Goertz geimplementeer was in die vroeë 1940s vir die hantering van radioaktiewe materiale. Met vordering in kern en ondersteunende tegnologieë, het die telewerksverigtingstelsels toegeneem in kompleksiteit asook gevorder in vermoeënsvaardigheid, wat gebruikers in staat stel om take te verrig vanuit enige plek op aarde, ongeag die fisiese afstand wat die gebruiker en die werksarea skei. Die lewensvatbaarheid van hierdie stelsels het ook toegeneem weens die belangstelling in teleteenwoordigheidrobotte, ruimtevaardige-robotte, reddings-robotte en militêre-robotte soos onbemandelug- voertuie (OLV) en onbemande-grond-voertuie(OGV). As gevolg van die belangstelling in telerobotiese stelsels is die ontwikkeling van ’n modulêre, gebruikers-gesentreerde telewerksverigting stelsel onderneem. Die huidige projek is ’n tweede iterasie hiervan. Telewerksverigting, en meer spesifiek, telerobotika stelsels ontwikelling, vereis dat stelselontwikkelaars ’n verskeidenheid kennisareas bemeester. Die ontwikkelaar moet ’n belans vind tussen gebruiker vereistes, bruikbaarheid asook tegniese ontwerp en prestasie vereistes. Menigde ontwikkelingsproses modelle is oorweeg en behandel in die konteks van Ingenieursbestuur (IB). ’n Stelselsontwikkeling proses is gevolg met ’n fokus op primêre en ondersteunende IB komponente. ’n Gemengde ontwikkeling is toegepass tot die projek wat die gebruiker as ’n hoof komponent van die stelsel in ag neem. Die oorhoofse ontwikkelingsmodel is die User-centred Systems Design (UCSD) proses, wat vir beide hardeware en sagteware ontwikkeling gebruik is. Vir die hardeware ontwikkeling is die UCSD toegepas soos dit uiteengesit is in die literatuur. Die sagteware ontwikkeling is voltooi met behulp van ratse metodes, “Rapid Application Development” RAD en “Extreme Programming” (XP) was oorweeg en XP was gekies as ontwikkelingsmodel. XP was die natuurlike keuse weens die gemak waarmee UCSD metodes en prinsiepe kon geinkorporeer word in die ontwikkelings proses. Hardeware onwikkeling het bestaan uit meganiese ontwerp, manipulasiegereedskap ontwerp, konfigurasie bestuur en ontwikkeling asook haptiese en visueleterugvoer stelselsontwerp van die fisiese stelsel insluitend die fisiese koppelvlakontwerp van die meester sel. Verder is sagtewareontwerp opgedeel in ’n haptiesebeheerstel met ’n kinematiese model ontwikkeling, videoterugvoerbeheer en gebruikersintervlak ontwerp. Die vermoëe van die stelsel om krag insette na te boots was verbeter met ’n gestadigde verbetering van 10%. Die reaksietyd van die stelsel is verbeter met ’n faktor van 10. Die stelsel het ’n verswakking getoon in die algehele hoekakkuraatheid, die oorsprong van die verswakking kan aan die beheerstelsel teogeken word. Verdere menslikefaktoranalise eksperimente is voltooi om die stelsel in twee tipiese gebruikgeval scenario’s te toets. Die eerste, ’n platvlak-eksperiment en die tweede ’n 3D plasingingstaak eksperiment. Die faktore van belang is ïdentifiseer as, visie-veld, terugvoervisie modus en insette modaliteit. Heuristiese prestasie-aanwysers soos tyd-tot-voltooiing en die aantal botsings vir ’n gegewe taak is gemeet. Stelselprestasie het slegs aansienlike verbetering getoon wanneer die stelsel met die haptiesebeheer modus bedryf word. Die visiefaktor ontleding het geen noemenswaardige resultate opgelewer nie. Terugvoervorms was na elke eksperiment voltooi. Vraelyste het getoon dat gebruikers die oogpunt van ’n lae hoek en 2D video oor 3D video verkies, terwyl die haptic beheer modaliteit verkies word.
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Costello, Stacy. "Evaluation on an on-site stormwater treatment device for sediment flux mitigation in the Lake Tahoe basin." Scholarly Commons, 2012. https://scholarlycommons.pacific.edu/uop_etds/836.
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Pollution from nonpoint sources is a leading cause of receiving water quality impairment. The largest source of nonpoint pollution is storm water runoff, which includes pollutants such as sediment, nutrients, metals, microorganisms, and organic compounds. Sediment is of particular importance because many pollutants are readily 5 adsorbed onto particles. In the Lake Tahoe basin, sediment is also significant because of its direct contribution to clarity attenuation. The most prudent control measure for mitigating sediment flux in the Lake Tahoe basin is infiltration, which captures runoff volume, allowing it to percolate into the soil and enter groundwater. All residential parcels in the Lake Tahoe basin are required to have an on-site infiltration system. These systems require rigorous maintenance to maintain full function. Negligence can lead to premature clogging from debris and accumulated sediment, and the cost of rehabilitating or replacing the system can be significant to homeowners. It is mandatory for a sediment trapping device to be installed to pretreat runoff discharged into the infiltration system; however, there is limited infomation regarding sediment trapping devices designed for residential use.
The objective of this research was to evaluate the performance of an on-site stormwater treatment device in removing sediment from simulated stormwater runoff. The sediment trapping device consists of removable, porous 200-micron nylon inserts for filtration and is designed to mitigate premature clogging infiltrative runoff control measures. Laboratory analysis of a full scale device model was performed. Removal efficiency, effluent concentration, and bulk solids removal were assessed for perfomance evaluation. The device demonstrated a median removal efficiency from grab samples of 74%, median total suspended solids effluent concentration of 72 mg/L, and removed 89% of the total solids introduced into the system. Economic and sustainability implications of the device were also assessed.
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Bibby, Lee. "Improving design management techniques in construction." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/793.
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Recent years has seen a significant drive away from traditional procurement routes with contractors finding themselves with an increasing responsibility for control of design - a process they have had little experience in managing. They now have to adapt accordingly. The learning curve is steep, not least because many projects must now be delivered fast track while co-ordinating increasingly complex fabric and content of buildings without a platform of accepted good practice to manage the design process. This is a major factor preventing the UK construction industry from delivering projects on time, to budget and to the specified quality. There is a need to educate an increasing number of people in design management techniques to equip them to manage today's fast moving and demanding projects. However, many current design management tools are insufficiently developed for industry application. Therefore, to improve design management in the industry, current techniques must be modified to align them with the needs of the modern design manager. This research has developed and tested a training initiative aimed at improving design management practice within a major UK Design and Construct Contractor. It comprises a Design Management Handbook, Design Management Training, Team Support and Project Monitoring. The Design Management Handbook is the core of the training initiative. It addresses critical aspects of design management practice and provides design management tools. Training provides guidance to project teams on the tools and practices. In Team Support project teams are supported in the implementation of the new practices and tools to help embed new ways of working in company practice. Project Monitoring establishes the impact of the new practices on project performance to demonstrate that they are working and thus reinforce change. To establish the training initiative's effectiveness and key findings, the impact of the initiative on design management performance has been explored. The research has established which practices and tools were used, which were not, as well as an understanding the applicability and performance of each Handbook practice and tool. From this, barriers to implementing new design management tools in industry were identified and strategies developed in order to overcome such barriers.
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Dorabiato, Luiz Fernando. "Sistema de ultra-som para caracterização de leite bovino." Universidade Tecnológica Federal do Paraná, 2007. http://repositorio.utfpr.edu.br/jspui/handle/1/1333.
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CAPES; CNPqEste trabalho apresenta o projeto, desenvolvimento e testes de um sistema de caracterização de leite bovino por ultra-som. Analisadores comerciais de leite bovino são utilizados em cooperativas e laticínios a fim de avaliar a qualidade do leite entregue pelos produtores. Entre as características avaliadas estão a quantidade de gorduras, extrato seco desengordurado e água adicionada ao leite. Estes índices são utilizados para estimar o rendimento da produção de laticínios e adulteração do leite. O sistema desenvolvido bombeia a amostra a ser analisada para o interior de uma célula de testes, que é aquecida a fim de fazer medições sob temperatura conhecida. Em seguida, o sistema adquire o valor da amplitude e tempo de propagação do pulso de ultra-som na amostra e relaciona estes parâmetros acústicos a valores de gorduras, extrato seco desengordurado, proteínas e água adicionada nas amostras de leite. O sistema tem boa reprodutibilidade, apresentando baixo Coeficiente de Variação (inferior a 8,8%) para análises dos componentes sólidos do leite – gorduras, proteínas e extrato seco desengordurado. Os testes de calibração apresentaram coeficientes de determinação entre os parâmetros acústicos (atenuação e velocidade de propagação) e os parâmetros a serem avaliados (teor de gordura, extrato seco desengordurado, proteínas e água adicionada) superiores a 97 % (R2 > 0,97), com erros padrão de estimativa inferiores a 1,25%, indicando baixa dispersão dos dados experimentais em relação às curvas de regressão. Para avaliar o protótipo desenvolvido, foram realizados testes comparativos com equipamentos de referência. Foram utilizadas amostras de leite proveniente de um único fornecedor. Apesar do pequeno número de amostras/fornecedores avaliados, os erros percentuais absolutos máximos obtidos para as análises de componentes sólidos foram de 12,6% para gordura, 12,37% para proteínas e 13,76% para extrato seco desengordurado. Já para a quantidade de água adicionada, os erros foram superiores a 40%, no entanto estes erros deverão ser reduzidos utilizando-se um conjunto maior de amostras/fornecedores durante o processo de calibração e avaliação final do protótipo desenvolvido. Os resultados preliminares obtidos permitem concluir que o sistema de ultra-som desenvolvido é adequado para a determinação dos principais componentes do leite bovino.
This work presents the design, development and tests of an ultrasonic milk analyzer. Milk analyzers are employed by dairy industry to evaluate the quality of acquired milk. Some of the assessed features are the fat content, solids non-fat and added water to the milk samples. These features are employed to estimate the production income of dairy products and milk adulteration. The system pumps a sample to the test cell, then the cell is warmed and the measurements are done at known temperature. Then, the system acquires the amplitude and the propagation time of the ultrasound pulse through the sample and correlates these acoustic parameters to the fat content, solids non-fat, proteins and added water in milk samples. The system showed good reproducibility, presenting low coefficient of variation (lower than 8.8%) for analysis of solid content in milk samples – fat, proteins and solids non-fat. The calibration tests presented determination coefficients between the acoustic parameters (attenuation and propagation time) and the milk components (fat content, solids non-fat, proteins and added water) higher than 97% (R2 > 0.97), with standard error of estimate lower than 1.25%, showing low dispersion of the experimental data in relation to the regression curves. To evaluate the developed prototype, comparative tests in milk samples of only one supplier were carried out using the prototype and reference equipments. In spite of the small number of samples evaluated, the maximum absolute percent errors obtained for the analysis of solid content in milk were 12.6% for fat content, 12.37% for proteins and 13.76% for solids non-fat. The percent errors obtained for the amount of added water were higher than 40%, however these errors should be reduced using a higher number of samples/suppliers during the final calibration/evaluation process of the developed prototype. The preliminary results allow to conclude that the ultrasound system developed is adequate to quantify the main components of bovine milk.
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Eusuff, M. Muzaffar. "Optimisation of an operating policy for variable speed pumps using genetic algorithms." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09ENS/09ense91.pdf.
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Undertaken in conjunction with JUMP (Joint Universities Masters Programme in Hydrology and Water Resources). Bibliography: leaves 76-83. Establishes a methodology using genetic algorithms to find the optimum operating policy for variable speed pumps in a water supply network over a period of 24 hours.
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Mach, Phillip M. "Design Considerations and Implementation of Portable Mass Spectrometers for Environmental Applications." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984177/.
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Portable mass spectrometers provide a unique opportunity to obtain in situ measurements. This minimizes need for sample collection or in laboratory analysis. Membrane Inlet Mass Spectrometry (MIMS) utilizing a semi permeable membrane for selective rapid introduction for analysis. Polydimethylsiloxane membranes have been proven to be robust in selecting for aromatic chemistries. Advances in front end design have allowed for increased sensitivity, rapid sample analysis, and on line measurements. Applications of the membrane inlet technique have been applied to environmental detection of clandestine drug chemistries and pollutants. Emplacement of a mass spectrometer unit in a vehicle has allowed for large areas to be mapped, obtaining a rapid snapshot of the various concentrations and types of environmental pollutants present. Further refinements and miniaturization have allowed for a backpackable system for analysis in remote harsh environments. Inclusion of atmospheric dispersion modeling has yielded an analytical method of approximating upwind source locations, which has law enforcement, military, and environmental applications. The atmospheric dispersion theories have further been applied to an earth based separation, whereby chemical properties are used to approximate atmospheric mobility, and chemistries are further identified has a portable mass spectrometer is traversed closer to a point source.
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Zimmerman, Nicole P. "Time-Variant Load Models of Electric Vehicle Chargers." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2297.
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In power distribution system planning, it is essential to understand the impacts that electric vehicles (EVs), and the non-linear, time-variant loading profiles associated with their charging units, may have on power distribution networks. This research presents a design methodology for the creation of both analytical and behavioral models for EV charging units within a VHDL-AMS simulation environment.
Voltage and current data collected from Electric Avenue, located on the Portland State University campus, were used to create harmonic profiles of the EV charging units at the site. From these profiles, generalized models for both single-phase (Level 2) and three-phase (Level 3) EV chargers were created. Further, these models were validated within a larger system context utilizing the IEEE 13-bus distribution test feeder system.
Results from the model's validation are presented for various charger and power system configurations. Finally, an online tool that was created for use by distribution system designers is presented. This tool can aid designers in assessing the impacts that EV chargers have on electrical assets, and assist with the appropriate selection of transformers, conductor ampacities, and protection equipment & settings.
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Suzuki, Eimi Veridiane. "Avaliação do potencial de aquecimento/resfriamento de um sistema de climatização passiva." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/348.
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O emprego de sistemas passivos de condicionamento de ambientes ao invés de equipamentos de climatização artificial pode ser uma solução bastante conveniente para diminuir o gasto de eletricidade e melhorar o conforto térmico de uma edificação. Uma das técnicas usadas para a melhoria do desempenho térmico de edificações é a utilização de “Paredes Trombe”. Este é um sistema de climatização passiva que utiliza ganhos solares associados à inércia térmica de uma parede para absorver calor no período frio sem bloquear suas perdas do período quente. Esta pesquisa tem como objetivo analisar o potencial de aquecimento/resfriamento de um sistema de climatização passiva baseado na utilização de uma Parede Trombe. Para isso, foram construídos dois protótipos em escala reduzida, sendo um deles com Parede Trombe e o outro em alvenaria de blocos de concreto, sem o sistema passivo. As medições ocorreram em períodos frios (datas) de 2011 e no período de verão de 2012, para configurações distintas da Parede Trombe. Os resultados mostraram que a Parede Trombe teve um resultado positivo tanto para o inverno quanto para o verão.The use of passive solar heating for achieving thermal comfort inside a building is a very convenient solution to reduce the cost of electricity. One of the techniques used to improve the thermal performance of buildings is using "Trombe Walls." This is a passive solar heating system that uses solar gains associated with the thermal inertia of a wall to absorb heat during cold periods without blocking their loss in the warm period. This research aims to analyze the potential for heating and cooling of a Trombe Wall. For this, two cells were built on a small scale: passive solar cell and a reference cell. The measurements took place in cold periods (dates), of 2011 and during the summer of 2012, for different configurations of the Trombe Wall. The results showed that the Trombe Wall had a positive result for both winter and summer.
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Vedapuri, Damodaran. "Design of a clamp-on ultrasonic flow meter for wet gas pipelines." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1178910814.
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Scarpin, Jorge Alberto. "Detector de raios X baseado no diodo pin." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2693.
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A radiação ionizante possibilitou à medicina a utilização do diagnóstico por imagem, cuja finalidade é obter uma avaliação médica dos tecidos e funções orgânicas do corpo humano. O seu uso, entretanto, trouxe alguns inconvenientes, como o excesso de radiação a que uma pessoa pode ficar exposta, podendo trazer graves consequências a sua saúde. Normas internacionais orientam quanto ao uso de equipamentos que se utilizam de radiação, quanto às doses sobre os pacientes e trabalhadores ocupacionais, bem como fornecem recomendações quanto à utilização dos equipamentos que produzem os raios X. Nos últimos anos, foram implementados programas para a garantia da qualidade para as empresas prestadoras de serviços radiológicos e para os equipamentos utilizados, trazendo assim, o maior benefício possível para aqueles que se utilizam da radiação ionizante. A proposta deste trabalho é promover uma análise sobre a utilização de um circuito simples e barato, capaz de detectar os raios X emitidos por um aparelho de radiodiagnóstico médico. O circuito elétrico utilizado contém um sistema de detecção de raios X utilizando como transdutor um diodo PIN. Através de quatro aparelhos de raios X fixos e um móvel, foram realizadas várias exposições com valores de tensão em kV, corrente em mA e tempo em s, que mostraram que o sensor foi capaz de detectar esta radiação para os diferentes valores ajustados no aparelho. O circuito foi desenvolvido baseado num sensor do tipo diodo PIN, elemento de reduzida dimensão, que pode ser operado à temperatura ambiente, e é capaz de indicar, através do sensor, a interação da junção com fótons de raios X possibilitando a detecção da energia destes fótons emitidos e teste de vazamento de radiação e acessórios radiológicos.Ionizing radiation allowed the medical use of diagnostic imaging, whose purpose is to obtain a medical evaluation of tissues and physiological functions of the human body. Its use, however, brought some problems, such as excessive radiation that a person can be exposed. International standards guide on the use of equipment that use radiation, as the doses on patients and occupational workers, and provide recommendations on the use of equipment that produce the X-rays. In recent years, programs have been implemented to guarantee the quality, thus bringing the greatest benefit to those who use ionizing radiation. The purpose of this work is to promote an analysis of the use of a simple circuit capable of detecting the Xrays emitted by a medical diagnostic radiology apparatus. The electrical circuit used contains an X-ray detection system using as transducer a PIN diode. The circuit is simple and inexpensive. Through a fixed X-ray apparatus, multiple exposures were performed with voltage values in kV, current mA and time s that showed the sensor could detect the presence of this radiation for different values set in the apparatus. The circuit was developed based on a diode type PIN sensor, small size element that can be operated at room temperature, and is able to indicate, via the sensor, the interaction of the junction with X-ray photons enabling the detection of the energy of these emitted photons and test the undesirable radiation emitted and radiological accessories.
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Miguel, Cristiano. "Avaliação das condições de radioproteção em radiologia intraoral." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1159.
Full textAbstract:
Este estudo apresenta a avaliação das condições de radioproteção em radiologia intraoral. A pesquisa foi realizada em parceria com o Instituto de Radioproteção e Dosimetria da Comissão Nacional de Energia Nuclear (IRD/CNEN). A coleta de dados foi feita por meio de pesquisa de campo quantitativa de caráter descritivo durante o período de setembro de 2013 a dezembro de 2014. Participaram voluntariamente do estudo, odontólogos da cidade de Curitiba - PR que atuam com equipamentos de raios X intraorais. A amostra da pesquisa consistiu em 97 odontólogos e 130 equipamentos intraorais instalados em 74 locais de atendimentos distribuídos em 39 bairros da cidade de Curitiba - PR. Foram avaliadas 21 clínicas odontológicas, 40 consultórios odontológicos, 1 hospital universitário, 8 unidades municipais de atendimento odontológico e 4 instituições de ensino. Os dados foram coletados por meio de formulários preenchidos pelo pesquisador, pelos odontólogos, e pela avaliação de controle de qualidade dos equipamentos de raios X. As avaliações de dose de entrada na pele, tamanho de campo de radiação e filtração total foram realizadas com kits dosimétricos fornecidos e avaliados pelo IRD/CNEN. As medidas do tempo de exposição e da tensão dos equipamentos de raios X foram realizadas com detectores não invasivos. A dose ocupacional dos odontólogos foi verificada com dosímetros termoluminescentes. Por meio de formulários e de um questionário (aprovado pelo Comitê de Ética em Pesquisa de Seres Humanos - UTFPR) foi possível identificar as características técnicas dos equipamentos, avaliar os procedimentos de trabalho e o conhecimento dos odontólogos em relação à radioproteção. Com os resultados da pesquisa é possível destacar que apenas 10% dos equipamentos avaliados atendem a todas as exigências das normas de radioproteção do Brasil. Entretanto, 84,5% das doses de entrada na pele dos pacientes foram consideradas como conforme. Em relação à exposição ocupacional, a radiologia intraoral mostra-se segura, porém os procedimentos de trabalho dos odontólogos, referentes à radioproteção podem ser otimizados. Grande parte dos odontólogos não utiliza posicionador na sua rotina, fazem o processamento químico das radiografias através do método visual, usam sempre o mesmo tempo de exposição para todas as regiões anatômicas e não observam os pacientes durante a aquisição das imagens. O estudo sugere que a falta de conhecimento e de interesse dos odontólogos em relação à radioproteção, a falta de manutenção periódica dos equipamentos e a falta de fiscalização da agência regulamentadora são os responsáveis pelas não conformidades observadas.This study presents an evaluation of the radiation protection conditions in intraoral radiology. The survey was conducted in partnership with the Radiation Protection and Dosimetry Institute of the National Commission of Nuclear Energy (IRD/CNEN). Data collection was performed using quantitative field research in a descriptive way during the period of september 2013 to december 2014. The study had the voluntarily participation of dentists in the city of Curitiba – PR, working with intraoral X-ray equipment. The research sample consisted of 97 dentists and 130 intraoral equipments which are installed in 74 care locations distributed in 39 neighborhoods in the city of Curitiba - PR. The study evaluated 21 dental clinics, 40 dental offices, 1 hospital, 8 municipal units of dental care and 4 educational institutions. Data were collected through forms checked out by the researcher, by dentists and the quality control evaluation of X-ray equipment. The evaluation of the entrance skin dose, radiation field size and total filtration were performed with dosimetric kits supplied and evaluated by IRD/CNEN. The exposure time and voltage measures of X-ray equipment were performed with noninvasive detectors. Occupational dose was measured with thermoluminescent dosimeters. Through appropriate forms and a questionnaire (approved by the Ethics Committee of Human being Research - UTFPR) it was possible to identify the technical characteristics of the equipment, review the working procedures and knowledge of the dentists in relation to radiation protection. Among the search results it is important to emphasize that only 10% of the evaluated equipment reaches all requirements of the Brazilian radiation protection standards. However, 84,5% of the entrance skin dose delivered to the patients was considered in accordance. Regarding occupational exposure, the intraoral X-rays seem to be safe, but the dentist’s working procedures, related to the radiation protection, can be optimized. Most dentists do not use positioners in their routine, make the chemical processing of X-rays through the visual method, routinely use the same exposure time for all anatomic regions and do not observe patients during image acquisition. The study suggests that the dentists’s lack of knowledge and interest in radiological protection, the lack of equipment regular maintenance and the lack of regulatory agency supervision are the responsible for the nonconformities observed.
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Drumond, Gisele Russo Canato. "Avaliação de exposição ocupacional em radiologia digital veterinária portátil." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/447.
Full textAbstract:
Este trabalho avalia a distribuição de dose recebida por trabalhadores envolvidos nos procedimentos de radiologia veterinária portátil digital e verifica a redução da dose obtida com a utilização de equipamentos de proteção individual. Para esta avaliação foram feitas medições utilizando dosímetros termoluminescentes tipo TLD-100, posicionados em sete diferentes pontos do corpo dos assistentes: mãos, tórax (por fora do avental), tireoide (por dentro do avental), cantos dos olhos esquerdo e direito e centro dos olhos e em cinco pontos diferente no médico veterinário: tórax (por fora do avental), tireoide (por dentro do avental), cantos dos olhos esquerdo e direito e centro dos olhos. As doses ocupacionais foram avaliadas em 63 procedimentos radiográficos de cães realizados com 49 assistentes e um médico veterinário na região metropolitana de Curitiba, PR. Os resultados mostram a importância do uso do protetor de tireoide e avental de chumbo para a redução da dose recebida pelos profissionais. As doses dos assistentes que seguraram os animais foram mais altas na região das mãos. Este estudo mostra a necessidade de medidas adicionais de proteção e a implementação de mecanismos de treinamento em proteção radiológica para os médicos e assistentes que trabalham com radiologia portátil digital.This study evaluates the distribution of the dose received by work-people involved in portable digital veterinary radiology procedures and checks the dose reduction obtained with the use of individual protection equipments. For this evaluation measurements were made using TLD-100 thermoluminescent dosimeters,positioned at seven different spots on the body of the assistants: hands, chest (outside the apron), thyroid (inside the apron), left and right eye corners and at the forehead, and in five different spots in the veterinarian: chest (outside the apron), thyroid (inside the apron), left and right eye corners and the center of the eyes. The dosage was evaluated through the 63 procedures performed with 49 assistants and a veterinarian in the metropolitan region of Curitiba, PR. The results show the importance of using thyroid protection and lead aprons to reduce the dosage received by the veterinarian and assistants. The dosages of the assistants who held the animals were higher in the areas of the hands. This study shows the need for additional protective measurements and the implementation of training mechanisms in radiation protection for physicians and assistants who work with portable digital radiology.
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Gonçalves, Felyppe Blum. "Avaliação da vibração e ruído ocupacionais no fresamento de pisos industriais." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1327.
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A constante mudança nos meios de trabalho ocorre devido a evolução tecnológica e industrial. Entretanto, com o advento de tais inovações, dificilmente o trabalhador da indústria não é submetido aos mais variados riscos ocupacionais resultantes dos processos produtivos. Diante deste contexto, o presente estudo teve como objetivo principal avaliar os níveis de vibração e de ruído aos quais os trabalhadores de uma empresa do setor da construção civil, especializada na manutenção e reformas de pisos industriais, estavam expostos durante suas jornadas de trabalho em duas frentes de trabalho. As medições foram realizadas em locais e dias distintos nos municípios de Curitiba e de São José dos Pinhais, ambos no estado do Paraná. Para a avaliação da vibração ocupacional, utilizou-se um acelerômetro junto ao trabalhador e um sensor triaxial acoplado na empunhadura dos equipamentos objeto de estudo, que foram duas diferentes fresadoras de piso. Posteriormente os dados foram processados e comparados com o novo texto do Anexo no 08 da Norma Regulamentadora NR-15, apresentado para consulta pública pelo Ministério do Trabalho e Emprego entre os meses de janeiro e fevereiro de 2014. Já para a medição do ruído utilizou-se um dosímetro de ruído junto ao trabalhador, cujo resultado final possibilitou a comparação com o Anexo no 01 da mesma Norma Regulamentadora. Os resultados finais indicaram níveis de exposição excessivos, superiores aos limites de tolerância determinados pela Legislação, tanto para vibração quanto para o ruído, gerando insalubridade para os trabalhadores expostos, em todos os locais onde foram realizadas as medições.The constant change in the means of work is done by technological and industrial developments. However, with the advent of such innovations, hardly the work of the industry is not subject to a variety of occupational hazards resulting from production processes. Given this context, the present study aimed to monitor the working hours of the employees of a company in the construction industry, specializing in industrial floor maintenance and renovations, as exposure of vibration and noise on two fronts work in the cities of Curitiba - PR and São José dos Pinhais – PR. The program took place in two locations and on different days. The workday adopted by the company is six hours daily. For the evaluation of vibration, we used accelerometer with the worker and coupled to the handle of the equipment object of study, a mill floor, triaxial sensor subsequently the data were processed and compared with the new text of Annex No. 08, NR 15, submitted for public consultation by the Ministry of Labour and Employment in the months of January and February 2014. As for noise measurement used a dosimeter with the worker, whose final results enabled comparison with the regulatory norm 15 - Annex No. 01. The final results indicate excessive exposure to the tolerance specified by the legislation, both vibration and sound pressure level, featuring unhealthy at all locations where measurements were performed.
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Garcia, Sotelo Gerardo Javier. "Get the right price every day." CSUSB ScholarWorks, 2005. https://scholarworks.lib.csusb.edu/etd-project/2729.
Full textAbstract:
The purpose of this project is to manage restaurants using a software system called GRIPED (Get the Right Price Every day). The system is designed to cover quality control, food cost control and portion control for better management of a restaurant.
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bhardwaj, vinay. "Label-free surface-enhanced Raman spectroscopy-linked immunosensor assay (SLISA) for environmental surveillance." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2321.
Full textAbstract:
The contamination of the environment, accidental or intentional, in particular with chemical toxins such as industrial chemicals and chemical warfare agents has increased public fear. There is a critical requirement for the continuous detection of toxins present at very low levels in the environment. Indeed, some ultra-sensitive analytical techniques already exist, for example chromatography and mass spectroscopy, which are approved by the US Environmental Protection Agency for the detection of toxins. However, these techniques are limited to the detection of known toxins. Cellular expression of genomic and proteomic biomarkers in response to toxins allows monitoring of known as well as unknown toxins using Polymerase Chain Reaction and Enzyme Linked Immunosensor Assays. However, these molecular assays allow only the endpoint (extracellular) detection and use labels such as fluorometric, colorimetric and radioactive, which increase chances of uncertainty in detection. Additionally, they are time, labor and cost intensive. These technical limitations are unfavorable towards the development of a biosensor technology for continuous detection of toxins. Federal agencies including the Departments of Homeland Security, Agriculture, Defense and others have urged the development of a detect-to-protect class of advanced biosensors, which enable environmental surveillance of toxins in resource-limited settings.
In this study a Surface-Enhanced Raman Spectroscopy (SERS) immunosensor, aka a SERS-linked immunosensor assay (SLISA), has been developed. Colloidal silver nanoparticles (Ag NPs) were used to design a flexible SERS immunosensor. The SLISA proof-of-concept biosensor was validated by the measurement of a dose dependent expression of RAD54 and HSP70 proteins in response to H2O2 and UV. A prototype microchip, best suited for SERS acquisition, was fabricated using an on-chip SLISA to detect RAD54 expression in response to H2O2. A dose-response relationship between H2O2 and RAD54 is established and correlated with EPA databases, which are established for human health risk assessment in the events of chemical exposure. SLISA outperformed ELISA by allowing RISE (rapid, inexpensive, simple and effective) detection of proteins within 2 hours and 3 steps. It did not require any label and provided qualitative information on antigen-antibody binding. SLISA can easily be translated to a portable assay using a handheld Raman spectrometer and it can be used in resource-limited settings. Additionally, this is the first report to deliver Ag NPs using TATHA2, a fusogenic peptide with cell permeability and endosomal rupture release properties, for rapid and high levels of Ag NPs uptake into yeast without significant toxicity, prerequisites for the development of the first intracellular SERS immunosensor.
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Dallegrave, Caroline Paola Mickosz. "Proposta de uma unidade terapêutica domiciliar baseada no protocolo PediaSuit." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1021.
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Introdução:O comprometimento de determinados grupos musculares e alterações sensório motoras são algumas das características apresentadas por crianças com paralisia cerebral, fazendo-se necessária a utilização de andadores e estabilizadores para auxiliar no ortostatismo e na marcha desses pacientes. Atualmente, existem equipamentos que favorecem estes aspectos, porém o custo ainda é bastante alto, tornando-os inacessíveis a uma grande parcela da população. Com o intuito de se apresentar uma alternativa de qualidade e custo reduzido, desenvolveu-se na UTFPR um andador/ estabilizador baseado no protocolo PediaSuit™, confeccionado em PVC. O suporte é dado através de elastômeros fixados a um cinto, permitindo assim uma marcha mais próxima do natural. Objetivo: Avaliar a marcha e a postura de crianças com Paralisia Cerebral a partir do uso de uma Unidade Terapêutica Domiciliar de baixo custo e baixa mecanização. Método: Foram realizados testes visando analisar a resistência mecânica do material utilizado e ensaios com o protótipo construído. O PVC mostrou ser um material com alta resistência nos testes de flexão e impacto. A massa máxima suportada pelo andador no teste realizado foi de aproximadamente 226 kg. Após a avaliação do equipamento, três crianças foram filmadas utilizando o andador em PVC e um andador comum. Aspectos da marcha e da postura foram avaliados por trinta fisioterapeutas através desses vídeos.Resultados: O andador em PVC apresentou melhores resultados em relação a todos os aspectos da marcha avaliados, promovendo uma deambulação mais próxima do normal. Em relação à resistência mecânica, os ensaios mostram que o PVC Ø32mm é um material adequado para a confecção de equipamentos de tecnologia assistiva, por ser capaz de suportar cargas elevadas sem se romper. A utilização desse material também proporcionou uma redução significativa no custo final do equipamentoIntroduction: The involvement of certain muscle groups and sensorimotor deficits are some of the characteristics displayed by children with cerebral palsy, making necessary the use of stabilizers and gait trainers to assist posture and gait of those patients. There are assistive technology devices that promote these aspects, but the cost is still quite high, making them inaccessible to most people. In order to present an alternative with lower cost, a PVC stabilizer/ gait trainer based on PediaSuit™ protocol was developed at UTFPR and Vitória Research Center. The support is provided by elastomers fixed to a belt, thereby allowing a more natural gait pattern. Objective: To evaluate the gait and posture of children with cerebral palsy during the use of a low cost/ low mechanization Therapy Unit Homecare. Method: Some tests were carried out to determine the strength of the prototype and the material itself. PVC proved to be a material with high strength in bending and impact tests. The maximum mass supported by the walker in the test conducted was approximately 226 kg. After evaluating the equipment, images of three children using a reguar gait trainer and the PVC home care unit were taken. Aspects of gait and posture were analysed by thirty physiotherapists through these videos. Results: The PVC home care unit showed better results in regarding all aspects of gait evaluated by promoting closer to normal gait. The mechanical strength tests show that PVC Ø32mm is a suitable material for fabrication of assistive technology equipment, to be able to withstand high loads without breaking. The use of this material also provided a significant reduction in the final cost of the product.
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Persaud-Sharma, Dharam. "An Assessment of Novel Biodegradable Magnesium Alloys for Endovascular Biomaterial Applications." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/950.
Full textAbstract:
Magnesium alloys have been widely explored as potential biomaterials, but several limitations to using these materials have prevented their widespread use, such as uncontrollable degradation kinetics which alter their mechanical properties. In an attempt to further the applicability of magnesium and its alloys for biomedical purposes, two novel magnesium alloys Mg-Zn-Cu and Mg-Zn-Se were developed with the expectation of improving upon the unfavorable qualities shown by similar magnesium based materials that have previously been explored. The overall performance of these novel magnesium alloys has been assessesed in three distinct phases of research: 1) analysing the mechanical properties of the as-cast magnesium alloys, 2) evaluating the biocompatibility of the as-cast magnesium alloys through the use of in-vitro cellular studies, and 3) profiling the degradation kinetics of the as-cast magnesium alloys through the use of electrochemical potentiodynamic polarization techqnique as well as gravimetric weight-loss methods. As compared to currently available shape memory alloys and degradable as-cast alloys, these experimental alloys possess superior as-cast mechanical properties with elongation at failure values of 12% and 13% for the Mg-Zn-Se and Mg-Zn-Se alloys, respectively. This is substantially higher than other as-cast magnesium alloys that have elongation at failure values that range from 7-10%. Biocompatibility tests revealed that both the Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. Gravimetric and electrochemical testing was indicative of the weight loss and initial corrosion behavior of the alloys once immersed within a simulated body fluid. The development of these novel as-cast magnesium alloys provide an advancement to the field of degradable metallic materials, while experimental results indicate their potential as cost-effective medical devices.
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Jalal, Ahmed Hasnain. "Multivariate Analysis for the Quantification of Transdermal Volatile Organic Compounds in Humans by Proton Exchange Membrane Fuel Cell System." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3886.
Full textAbstract:
In this research, a proton exchange membrane fuel cell (PEMFC) sensor was investigated for specific detection of volatile organic compounds (VOCs) for point-of-care (POC) diagnosis of the physiological conditions of humans. A PEMFC is an electrochemical transducer that converts chemical energy into electrical energy. A Redox reaction takes place at its electrodes whereas the volatile biomolecules (e.g. ethanol) are oxidized at the anode and ambient oxygen is reduced at the cathode. The compounds which were the focus of this investigation were ethanol (C2H5OH) and isoflurane (C3H2ClF5O), but theoretically, the sensor is not limited to only those VOCs given proper calibration.
Detection in biosensing, which needs to be carried out in a controlled system, becomes complex in a multivariate environment. Major limitations of all types of biosensors would include poor selectivity, drifting, overlapping, and degradation of signals. Specific detection of VOCs in multi-dimensional environments is also a challenge in fuel cell sensing. Humidity, temperature, and the presence of other analytes interfere with the functionality of the fuel cell and provide false readings. Hence, accurate and precise quantification of VOC(s) and calibration are the major challenges when using PEMFC biosensor.
To resolve this problem, a statistical model was derived for the calibration of PEMFC employing multivariate analysis, such as the “Principal Component Regression (PCR)” method for the sensing of VOC(s). PCR can correlate larger data sets and provides an accurate fitting between a known and an unknown data set. PCR improves calibration for multivariate conditions as compared to the overlapping signals obtained when using linear (univariate) regression models.
Results show that this biosensor investigated has a 75% accuracy improvement over the commercial alcohol breathalyzer used in this study when detecting ethanol. When detecting isoflurane, this sensor has an average deviation in the steady-state response of ~14.29% from the gold-standard infrared spectroscopy system used in hospital operating theaters.
The significance of this research lies in its versatility in dealing with the existing challenge of the accuracy and precision of the calibration of the PEMFC sensor. Also, this research may improve the diagnosis of several diseases through the detection of concerned biomarkers.
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Tomo, Zonwabele Zweli Simon. "Improving the reliability of a chemical process plant." Thesis, 2012. http://hdl.handle.net/10210/4887.
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M.Phil.In modern society, professional engineers, technologists and technical managers are responsible for the planning, design, manufacture, maintenance and operation of the processes and systems ranging from simple processes to complex systems. The failure of these can often cause effects that range from inconvenience and irritation to severe impact on the society and its environment. Users, customers and society in general expect that products be reliable and safe at all times (Allan & Ballinton 1992). The biggest investment in any plant is, arguably, on individual plant equipment. It is therefore reasonable to give the greatest attention possible to the health and integrity of equipment that form part of the chemical process plant.Most of plant failures occur without warning and this result in equipment breakdowns, huge production losses and expensive maintenance. The reaction to plant failures has, in most cases, been a reactive maintenance which means that the plant equipment must fail before the cause of fault is investigated and the equipment is repaired. Reactive maintenance has shortcomings in that it is successful in solving problems temporarily but does not guarantee prevention of fault recurrence. Equipment and process failures waste money on unreliability problems. The question that arises is. ‘How reliable and safe is the plant during its operating life?’ This question can be answered, in part, by the use of quantitative reliability evaluation. The growing need to achieve high availability for large integrated chemical process systems demands higher levels of reliability at the operational stage. Reliability is the probability of equipment or processes to function without failure when operated correctly for a given interval of time under stated conditions. This research dissertation is aimed at developing equipment optimisation program for the chemical process plant by introducing a logical approach to managing the maintenance of plant equipment. Some relevant reliability theory is discussed and applied to the Short – Path Distillation (SPD) plant of SASOL WAX. An analysis of the failure modes and criticality helps to identify plant equipment that needs special focus during inspection.
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"Real-time observer model for Kraft wood digester." Thesis, 2005. http://hdl.handle.net/10413/2838.
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At SAPPI-Tugela a continuous Kraft wood chip digester operates in EMCC mode (extended modified continuous cooking). Chips are initially exposed to a NaOH / Na2S liquor at high temperature in the top section. The chips move downward in plug flow passing circumferential screens used to draw liquor for various circulations. About midway down the spent black liquor is removed and the chips enter the cooler bottom section where some further reaction and washing occurs. Liquor level and chip level are maintained close to each other near the top. Chips require 8-12 hours to pass through the digester, depending on the chip feed rate. The key parameter of interest at the digester exit is the Kappa number, which is a measure of the extent of delignification which has occurred. Different board and paper products require different Kappa number pulp feed. (Final properties such as tensile, tear and bursting strengths will also depend on the way fibres have been modified in the digestion). The objective of this investigation is to predict the Kappa number of the product pulp in real-time, thus facilitating quicker reaction than the present dependence on laboratory analysis permits, possibly even allowing closed-loop control. The extent of delignification depends on liquor strength, temperature and exposure time, with final Kappa number also depending on the properties of the chip feed (wood type and moisture content). Compensation to maintain a steady Kappa number is made difficult by the long and varying residence time, and the fact that any changes apply to the whole profile held up in the digester. A number of static models for Kappa number prediction have been developed by previous workers, but these do not compare well with plant measurements. The collection of data from the Sappi-Tugela reactor, and the pulp quality reports, have been used to determine an efficient model. This step required a considerable data collection exercise, and similar results to the quality reports have been obtained using a simple linear model based on this data. The problem of model error is being reduced by arrangement as a Smith Predictor, in which the model is intermittently corrected by available laboratory analyses. At the same time, an interface was created, in order to synchronise measurement data for the chips presently leaving the reactor. In order to deal with the dead time, each parcel of chips entering the reactor is effectively tracked, and the changes in Kappa number integrated for reaction time under the varying conditions in transit. Knowing the present inventory of the reactor, this model can also be run forward in time as a predictive controller, to determine optimal control actions for maintenance of the target Kappa number.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2005.
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Mbulawa, Xolani Proffessor. "Development and evaluation of silicone membrane as aerators for membrane bioreactors." Thesis, 2005. http://hdl.handle.net/10321/314.
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Thesis (M.Tech.: Chemical Engineering)-Dept. of Chemical Engineering, Durban University of Technology, 2005 1 v. (various pagings)In bubble-less aeration oxygen diffuses through the membrane in a molecular form and dissolves in the liquid. Oxygen is fed through the lumen side of silicone rubber tube. On the outer surface of the membrane there is a boundary layer that is created by oxygen. This then gets transported to the bulk liquid by convective transport created by water circulation through the pump. The driving force of the convective transport is due to concentration difference between the dissolved oxygen in water and oxygen saturation concentration in water at a particular temperature and pressure. The design of a membrane aerated bioreactor needs an understanding of the factors that govern oxygen mass transfer. It is necessary to know the effects of operating conditions and design configurations. Although various methods of bubble-less aeration have been reported, there still exists a lack of knowledge on the immersed membrane systems. This study is aiming at contributing to the development of an immersed membrane bioreactor using silicone rubber tubular membrane as means of providing oxygen. The secondary objective was to investigate the influence that the operating conditions and module configuration have on the system behaviour. From the experimental study, the characteristic dissolved oxygen -time curve show that there is a saturation limit equivalent to the equilibrium dissolved oxygen concentration, after which there is no increase in dissolved oxygen with time. At ambient conditions the equilibrium dissolved oxygen is approximately 8 mg/L. This is when water is in contact with air at one atmospheric pressure. At the same conditions the equilibrium dissolved oxygen concentration when water is in contact with pure oxygen is approximately 40 mg/L. This is why all the experiments were conducted from 2mg/L dissolved oxygen concentration in water, to enable enough time to reach equilibrium so as to determine mass transfer coefficient. The most important parameters that were investigated to characterise the reactor were, oxygen supply pressure, crossflow velocity, temperature and module orientation. Observations from the experimental study indicated that when the system is controlled by pressure, crossflow does not have a significant effect on mass transfer. When the system is controlled by the convective transport from the membrane surface to the bulk liquid, pressure does not have a significant effect on mass transfer. All four effects that were investigated in the study are discussed.
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Riley, Rodger Keith. "The kinetics of steam gasification of South African coals." Thesis, 1990. http://hdl.handle.net/10413/8661.
Full textAbstract:
The prime objective of a current research project at the University
of Natal is to develop a novel autothermal fluidised bed coal
gasifier which is capable of efficiently producing synthesis quality
gas (rich in hydrogen and carbon monoxide) from discard of duff coal
resources using air and steam as the reactant gases.
The development of this gasifier was initially motivated to utilise
the ever increasing supply of discard coal in South Africa which
represents a significant potential source of energy and currently
poses severe environmental pollution hazards caused by spontaneous
combustion and wind erosion of the discard coal dumps. Recently,
however, the gasifier has been considered for the conversion of more
general coal resources in an Integrated Coal Gasification Combined
Cycle process (IGCC) for the production of electricity.
The knowledge of the kinetics of steam gasification of local coal
resources is of vital importance to the design of this gasifier.
However, no such kinetic data are available of which the author is
aware.
This thesis presents the following contributions to the overall
knowledge of the gasifier
(a) The development of a micro reactor to measure the rate of
reaction of the steam gasification of coal-char at
temperatures of up to l000oC and pressures up to 5 bar
absolute;
(b) Kinetic studies using the microreactor on the steam
gasification of coal-chars derived from Bosjesspruit and
Transvaal Navigation coal samples.
The following principal results were obtained with
Bosjesspruit coal-char :
The rate of steam-char gasification is very sensitive to
variations in the temperature of reaction in the range
840°C to 920°C.
Neither the rate of steam-char gasification nor the product
gas composition are affected by the steam partial pressure in
the range 1.8 to 4.8 bar absolute;
The concentrations of the H2 and CH4 components of the product
gas stream rapidly approached their respective equilibrium
compositions, whereas the concentrations of CO and CO2
gradually approach their respective equilibrium compositions
during gasification at a rate which is typical of the
stoichiometry of the Boudouard reaction.
The average product gas composition is independent of the
temperature of reaction in the range 840°C to 920°C and is
approximately 49% H2, 32% CO, 17% CO2 and 2% CH4 on a molar
basis;
The steam gasification kinetic data are well described by a
fundamental Arrhenius-type volumetric reaction model at
(c) temperatures of up to 920°C. The value of the activation
energy for the reaction is 146 kJ/gmol, which indicates that
the gasification kinetics are controlled by the rates of the
chemical reactions (ie. C + H2O = CO + H2 and C + CO2 = 2CO)
at temperatures up to 920o C; There are no major differences between the kinetics measured
for Bosjesspruit coal-char and those reported in the
literature for foreign coal-chars.
The experimental results obtained for the steam gasification
of char derived from Transvaal Navigation coal show that the
concentrations of both the Hz and the CH4 in the product gas
stream rapidly attain their respective equilibrium values and
remain approximately constant throughout gasification, whereas
the concentrations of CO and CO2 gradually approach their
respective equilibrium values during the course of
gasification and almost attain equilibrium concentrations as
the conversion of carbon nears completion. The rate of steam
gasification of this char is therefore also controlled by the
rate of the Boudouard reaction.
The mathematical development of a steady-state,
one-dimensional compartment model of the gasifier. The model
is also presented in the form of a Fortran 77 computer program
which is designed to run on a personal computer. The program
is capable of simultaneously solving the overall material and
energy balances of the gasifier to a tolerance of l% within 15
minutes when using a microprocessor which operates at 10 Mhz.
(d) The gasifier simulation program is currently being used in the
design of a pilot scale gasifier which is intended to
demonstrate the capability of the process on a continous basis
of operation.
(e) Experimentation on the air-steam gasification of Bosjesspruit
coal using a mini-pilot scale gasifier. These experiments
have successfully demonstrated the feasibility of the
production of a gas stream which is rich in hydrogen and
carbon monoxide. The composition of the product gas stream
compares well with the predictions of the simulation model of
the gasifier.Thesis (Ph.D.)-University of Natal, Durban, 1990.
47
Tuzun, Mustafa Asim. "A study of comminution in a vertical stirred ball mill." Thesis, 1993. http://hdl.handle.net/10413/6251.
Full textAbstract:
A 20 litre experimental batch and continuous test rig and 5 litre batch
and 50 litre continuous test rigs for stirred ball milling were built at the University
of Natal and Mintek respectively. All the mills featured a grinding vessel with a
central shaft equipped with pins and a torque measurement system. A washed
chrome sand from the Bushveld Igneous Complex was used for the grinding
experiments. Particle size analysis of products was performed using standard
sieves and a Malvern Particle Sizer.
Batch tests were run in the 20 litre stirred ball mill to achieve efficient
grinding conditions. The effects of grinding conditions such as pulp density, media
size, media density and shaft rotation speed and mill design parameters such as
ball load, pin spacing and pin diameter on product size, power consumption and
media wear were studied. It has been shown that the median size of the product
can be calculated by the Charles' Energy-Size Equation.
The stirred ball mill has been found to be more energy efficient than the
tumbling ball mill. An energy reduction of 50% was possible for a product size of 6
microns when the stirred ball mill was employed instead of the tumbling ball mill.
The energy input per ton of grinding media in the stirred ball mill could be 10 times
higher than for the tumbling ball mill. Although during coarse grinds the media
wear was higher in the stirred ball mill than in the tumbling mill, it became less so
as grinding proceeded and for a product median size of 4.8 microns it was the
same.
Using a 5 litre batch mill, an experimental programme was designed to
study the comminution characteristics of the stirred mill. A factorial design was
prepared with the following parameters, which influence grinding in the stirred ball
mill: pulp density, pin tip velocity and ball density and size. The energy required for
grinding the chromite sand in the stirred ball mill was determined by the use of
Charles' Equation. The findings were in agreement with the results predicted by
this equation. It was shown that the Rosin-Rammler size distribution equation was
a suitable procedure for presenting and comparing grinding data obtained from the
stirred ball mill. The factors that had the greatest effect on grindability were, in
order of importance: ball size, pin tip velocity and ball density. Interactions
between grinding parameters were negligible. results implied that accurate
predictions can be made to determine the grinding conditions required to achieve
a desired product specification.
An attempt was made to study the grinding kinetics the chromite are
using the mass population·balance model. Grinding tests were performed with two
mono size fractions ·53+38 and -38+25 microns and natural feed ·100 microns
using various pin tip velocities, ball densities and within the normal stirred
ball milling operating range. relationship between the ball diameter and the
particle was explained by the "angle of nip" theory which applied for roller
crushers. It was shown that the particle giving the maximum breakage rate
was directly proportional to the ball diameter. Estimated grinding kinetic
parameters from monosize provided a good basis for predictions of
natural feed. However, the breakage rate obtained from monosize tests
appeared to be lower than those from the natural feed It was found that if the
selection and breakage functions were determined by monosize tests, it was
possible to modify selection function parameters by back-calculation which gave
the best fit to the natural feed size. A good correlation was obtained between the
experimental and product distributions using a population-balance
model. The links between the empirical model combining Charles' and
Rosin-Rammler equations and the first-order batch grinding equation were also
shown.
The stirred ball mills were operated in batch and continuous mode. The
median size of the products from the batch stirred ball mill experiments closely
matched those of the continuous grinding experiments under similar grinding
conditions. Using a salt solution as a tracer material, an attempt was made to
estimate the residence time distribution based on a simplified analysis of the
motion of the water in tile mill.
The current scale-up methods for the stirred ball mill are discussed. A
torque model was developed for given shaft geometry and ball relating the
power rements of the stirred ball mill to the following prime design and
operating parameters : mill diameter, mill height, pin tip velocity and effective
density of the mill load. The basic assumptions underlying the model were that the
mill content behaved as a fluidised bed, consequently a P effg h type model for the
pressure was applied throughout the grinding media bed the effective charge
velocity was proportional to the pin tip velocity. It was found that pin spacing, pin
diameter and ball diameter significantly affected the mill torque. A semi-empirical
torque model was derived to include these parameters. The relationships
formulated from these models were shown to be in excellent agreement with
experimental results.Thesis (Ph.D.)-University of Natal, Durban, 1993.
48
Lacave, Benoit. "Modelling and control of a co-current sugar dryer." Thesis, 2001. http://hdl.handle.net/10413/9056.
Full textAbstract:
The drying of sugar is the last step in the recovery of solid sugar from sugar-cane. To ensure
that the sugar can be transported and stored, the final moisture content leaving the sugar mill
must be carefully controlled.
Data spanning periods of normal plant operation were collected at the Tongaat-Hulett Ltd
Darnall sugar mill. These measurements were reconciled to achieve instantaneous mass and
energy balances across the sugar dryer.
Using these measurements, a general model has been developed to simulate the sugar drying. It
includes ten compartments through which the sugar and drying air flow, with a mass and energy
balance in each compartment. It was assumed that a "film" around the sugar crystal is
supersaturated, and that crystallisation is still occurring. A sorption isotherm determining the
equilibrium moisture content of the sugar, at which point mass transfer ceases, was included.
The model has been matched to process measurements by adjusting the heat and mass transfer
coefficients.
A Dynamic Matrix Controller was developed and tested off-line on the model, using the
reconciled measurement sequences. The controller manipulated the inlet air temperature in order
to control the exit sugar moisture content. The model predictive control format successfully
dealt with the large process dead-time (5 minutes).Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.
49
Nel, Coenrad Marais. "Reliability engineering of a hospital oxygen supply system." Thesis, 2012. http://hdl.handle.net/10210/7426.
Full textAbstract:
M.Ing.This dissertation covers a literature study of the reliability engineering, and this is then applied to the hospital oxygen supply system in order to determine the reliability of the system. The hospital oxygen supply system must comply with international and local legislation, which insists that the reliability of the system must be very high, since it supports life in the hospital. Since there were no previous studies conducted in terms of the oxygen supply system to the knowledge of the author, it definitely opens a new study field for the application of reliability engineering concepts. In the research it was found that no records were kept by the company on the failures occurring with the oxygen supply system. This increased the difficulty to calculate the actual reliability of the supply system. A reliability prediction was done, based on the failure rate data from a database. The reliability prediction of the .system was very low, and possibly not a very accurate prediction of the actual reliability of the system. The author therefore created a reliability calculation program, which calculates the reliability of the system and also keeps, an accurate failure data record on each component of the system. The main conclusion reached with this dissertation is that failure data feedback, and accurate records are a very important factor of reliability engineering. This may influence the company's ability to rectify design changes in their systems, as there is no idea where the failure occurred and how much money value is linked to the failures occurring.
50
"Measuring rapid kinetics by electroanalytical methods in droplet-based microfluidic devices." Thesis, 2011. http://library.cuhk.edu.hk/record=b6075362.
Full textAbstract:
Han, Zuoyan.Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 75-81).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.