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1
Boughtflower, Robert J. "Operating parameters for capillary electrochromatography (CEC)." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/12403.
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Miniaturisation of chromatographic systems is becoming increasingly desirable. Future developments will demand the analysis of smaller samples, at faster rates, with increasingly complex separations required. These demands are already starting to exceed the capabilities of conventional HPLC systems. Systems will require more column efficiency, operation at higher flow rates and detection of the undiluted eluent in the most sensitive detectors available. CEC offers the opportunity to achieve these goals. The main obstacles to using CEC reliably are the relatively unstable nature of purely electrically driven flows in packed beds, the lack of good quality CEC columns and the lack of dedicated instruments to perform CEC analysis. Also, CEC shares some of the same problems with HPLC of miniaturising the separation system without incurring dispersion related losses. The work detailed in this thesis contributes considerable advancements in most of these areas. Novel methods to produce high quality columns are described. The work demonstrates effective methods for coupling CEC to MS that make allowance for control of dispersion. The thermal limits of operation are discussed and demonstrated. Pressure-assisted CEC, demonstrating the practicality of performing CEC based analysis that is as reliable as current HPLC systems is shown. Proper optimisation of these type of uses will ultimately deliver CEC in a reliable format which will encourage a whole new audience of users to reap the benefits available.
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Barnard, L. J., Beer D. J. De, and R. I. Campbell. "Parameters affecting spin casting of decorative and mechanical parts." Journal for New Generation Sciences, Vol 7, Issue 2: Central University of Technology, Free State, Bloemfontein, 2009. http://hdl.handle.net/11462/529.
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Published Article<br>Spin casting is widely used as a batch manufacturing process for decorative products. In the process, moulds are filled by taking advantage of the centrifugal effect, which is used to increase the pressure within the moulds, resulting in more detailed products. In this study, we analyse the different parameters that could affect the casting of mechanical parts through spin casting. Through this study, the user will be guided in the selection of parameters that will result in a certain degree of accuracy. The parameters were determined by performing numerous experiments using zinc alloy and tin-based pewter as casting materials. Results were obtained by casting approximately 15 000 parts in various positions, and at various clamping pressures, rotational speeds and temperatures in both the mould and the material. The experiments were undertaken by varying one parameter at a time, and with each set parameter repeated once, resulting in 100 test pieces per parameter for evaluation. From the results obtained, a series of critical factors and parameters, which are driven by part characteristics or features, has been studied. Contrary to following a modelling approach, the research was conducted following an action-research approach, with planned activities, but where actual results have defined the follow-up procedures. These guidelines will help industrial users ensure the accuracy of parts produced by spin casting. Also, since this project attempted to create a database of results that can be applied in future, it furthermore implies that the data created for the first time can be used in a numerical modelling approach in further / follow-up research. No such data was available from any previous research.
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Rothén, Niclas, and Jacob Aho. "Semi Solid Metal Casting : Study Of Slurry Preperation Parameters." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36446.
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This thesis work is an experimental study of one type of Semi-Solid Metal casting (SSM) process which is called RheoMetalTM. This method is an efficient type of Rheocasting that creates a semi-solid slurry within 30 seconds that is used for a high pressure die casting machine. The purpose of using a slurry in a high pressure die casting machine is that the slurry has a higher viscosity due to its solid fraction. This makes the filling of the die cavity more laminar which reduces air entrapment in the casting. The difficulty with this type of casting is to control the process parameters to be able to insure a casting with desired properties. A few studies within RheoMetalTM has already been made but there is still a lack of knowledge of to what extent the process parameters affect the slurry. The goal in this work is to study how the different RheoMetalTM process parameters influence the primary α-Al solid fraction, shape and size. The process parameters that were studied in this work was the stirring rate, superheat and EEM amount. In this study, the so called growth layer has been removed to make more precise calculations of the primary α-Al. This work also aims to study how grain refinement affect the primary α-Al which is commonly used to improve the quality of castings. To be able to perform this study, both practical and theoretical work has been implemented. The casting process involved making of ladles and preparation of various equipment. The cast samples were then prepared by standard metallurgy procedure for optical analyse of the microstructure. A special etching reagent was used to analyse the microstructure in a microscope. The etching is called Weck’s reagent and its purpose is to differentiate the growth layer from the primary α-Al. The growth layer is formed during quenching and by excluding it, the calculation of the slurry’s primary α-Al becomes more precise. This is because the slurry is not quenched before it is inserted into the high pressure die casting machine, therefore no growth layer is formed. To analyse the cast samples, a special program was used to identify and to calculate the solid fraction, shape and size of the primary α-Al. The result from the calculations made by the program gave different tendencies when changing the EEM amount. The stirring rate showed a tendency to decrease the solid fraction and increase the shape factor. The superheat decreased the solid fraction and increased the shape factor. The grain refinement also decreased the solid fraction and increased the shape factor. There was no clear tendency showing that the equivalent circular diameter of the primary α-Al was affected by any of the parameters.
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Masini, Alessandro. "Influence of the casting parameters on the membrane morphological characteristics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23058/.
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During the last century, the importance of membranes has increased drastically in our society; following this trend, their use in everyday life and in the industrial sector has dramatically rised. Consequently, membranes have been object of study in order to develop new material with new characteristics. This work aims at improving a current GVS portfolio-product, by developing a new filter based on alternative material and to substitute a competitor 3 membrane, whose production will be stopped due to the PerFluoroOctanoic Acid content, in a medical device that has to retain human urine. Firstly, the new polymer was studied, in order to understand how it affects membrane properties; once the basic information were obtained, we moved to analyze the influence of all the parameters in the solution preparation and in the casting process. Additionally, we have analyzed and selected the most appropriate membrane support and casting knife, to produce the most reliable membrane. Once we checked all the parameter, a first industrial trial was done based on the knowledge previously obtained; later, the trial has been analyzed to verify the stability of the product and to confirm the success of the industrial scale-up. The industrial trial has been compared with competitors’ membrane after urine test were carried out; the industrial trial showed superior results compared to the other membrane. Later we analyzed the impact of a standard laboratory testing protein on membranes, to observe if they were the main responsible for the pore occlusion after urine contact. Competitor 3 retains the same amount of protein of other membrane, for this reason, the hypothesis previously made was rejected.
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Mäkinen, Katri. "Optimisation of local material parameters : Optimising local material parameters in ductile cast iron cylinder head casting." Thesis, Jönköping University, JTH, Material och tillverkning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54500.
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The constantly tightening emission regulations demand the engines to be moreefficient, to get more power out of smaller engines. Higher engine loads andcomponent temperatures are causing more stresses to engine components. Therefore,a company that produces engines wanted to study if it would be possible to increasethe capabilities of the components by optimising the used material. In this final project work, a cylinder head will be studied. The cylinder heads for theengines are made of ductile cast iron. The limits of that material are near safety limits,and therefore a better material is needed. In this work are some previous studiesanalysed and tried to find how to optimise the used material. The optimised materialshould have better thermal conductivity properties combined with sufficient strengthproperties. Previous studies were analysed to gather knowledge of the elements that affect thematerial parameters. Those studies showed that copper, silicon, pearlite fraction, andthe use of chills are the elements to be optimised. Silicon and pearlite fraction waschosen as optimisation parameters because of their effect on the thermal conductivityand strength properties. Copper was chosen as an optimisation variable due to its effecton the pearlite formation. Chills were used to affect the cooling rate and thereby thepearlite formation. The work was made using MAGMASOFT™ simulation software to simulate cylinderhead casting. The simulated cylinder head was divided into 4 parts for the simulations.For those sections were then set targets for pearlite fraction according to previousstudies. The silicon content was kept constant in the simulation, based on the studiespresented in this work. Copper content was simulated with variations from 0 to 0.7weight-%, and chill heights were simulated from 20 to 60 mm and without chills. After simulating the different variables, the results were analysed. Then the selectedcasting simulation result was mapped to finite element simulation mesh to include thelocal material parameters to finite element simulation. With the finite elementsimulation, the estimated lifetime of the component was simulated. By analysing the casting simulation results, an optimal combination was found. Theoptimal material parameters for a cylinder head casting would be copper 0.5weight-%, silicon 1.9 weight-% and chills thicker than 40 mm on the flame plate. Theoptimised material gives more possibilities to develop engines even further when thecomponent demands are growing.
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Ivanchenko, S. E., I. O. Dulina, A. G. Nikulin, R. O. Kyrpal, S. O. Umerova, and A. V. Ragulya. "The Influence of Slip Characteristics and Casting Parameters on the Thickness of Thin Films Obtained by Tape Casting." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35213.
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Tape casting slips with different composition have been prepared using BaTiO3 nanopowder with a particle size in range of 20-25 nm. Ethanol, low polar organic solvent and menton were used as the sol-vents. Polyvinylbutyral and Butvar were used as binders. Dibutyl phthalate and polyethylene gly-col where used as plasticizers. Rheological properties of BaTiO3 suspensions were carried out on a rotary rhe-ometer. Casted tapes have been characterized by optical microscopy and optical profilome-try. Suspensions for tape casting characterized by pseudoplastic and pseudoplastic-dilatancy nature of the flow. The thick-ness of thin ceramic tapes depended on the height of doctor blade gap, the speed of the carrier and the vis-cosity of the suspension along with it’s rheological characteristics. Thickness of ceramic green tape in a greater extent determinated by the casting parameters, composition of the suspension and its viscosity. The average tape thickness was 2.5 μm for low viscosity slips and near 5 μm for high viscosity slips with same blade gap in 50 μm. Roughness of tape depended on type of used solvent and its polarity and varies between approximately 500 nm for low polar solvent up to 1 μm for polar one.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35213
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Siavashi, Kiavash. "The effect of casting parameters on the fluidity and porosity of aluminium alloys in the aost foam casting process." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3525/.
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The Lost Foam Casting process has been firmly established for Aluminium and ferrous alloys. This process offers many advantages over conventional casting processes but its full potential has yet to be reached due to the many defects introduced to the casting associated with decomposition of the foam pattern during mould filling. The foam pattern commonly used in this process is Expanded Polystyrene (EPS) which degrades to liquid and vapour byproducts. The liquid decomposition byproducts travel to the metal/mould interface, where the globules of liquid foam can become trapped against the coating and their molecular weight is reduced due to the heat from the molten metal. At the same time, they release bubbles of gas into the castings. These globules can wick into the refractory coating only if their molecular weight is sufficiently reduced to below a critical molecular weight. In this study, to improve the quality of Aluminium alloys made by Lost Foam Casting, easier removal of the decomposition byproducts was obtained by using low molecular weight foam patterns. The molecular weight of expanded Polystyrene was not reduced when it was exposed to γ-rays because of cross-linking while the molecular weight of Poly Methyl Methacrylate (PMMA) was significantly due to chain session. Therefore, plates of Probead-70™ (a copolymer of Polystyrene 30 wt %-Poly Methyl Methacrylate 70 wt %) were exposed to γ-rays and reduced their molecular weight by up to about 85% below the critical molecular weight value. With low molecular weight foam patterns the decomposition byproducts require less reduction to reach the critical molecular weight to become absorbed by the coating, and consequently less defects are introduced into the casting. γ-radiation was employed to reduce the molecular weight of the foam. The porosity content of the castings was significantly reduced leading to an improvement of their mechanical properties such as their fatigue life which was increased by 100%. Lost Foam Casting has also been reported to experience complexities with fluidity. Misrun is likely to occur in Lost Foam Casting due to the formation of a large amount of gas at the metal/foam interface, increasing the back pressure, compared to the conventional castings. This reduces the velocity of the molten metal which might lead to solidification of the molten metal before filling the mould entirely. In the current work, a reproducible fluidity test was designed and the effects of different casting parameters on fluidity were examined. In some of the castings inserted thermocouples were employed to study the filling behaviour to determine the velocity of molten metal, thickness of the metal/foam interface and the time of freezing. It was concluded that it is not recommended to alter the coating thickness in order to improve fluidity, because the effect of coating thickness depends on the pouring temperature of the castings and permeability of the coating. The metallostatic pressure was found to affect the fluidity insignificantly (within the values in the current work, 2600-2700 Pa). Instead, increasing coating permeability, decreasing the density of the foam pattern and increasing the pouring temperature were found to increase the fluidity in Lost Foam Casting. However the effect of increasing pouring temperature and decreasing foam density may be detrimental to the quality of castings. The molecular weight of the foam pattern and the use of brominated foam patterns did not have a considerable effect on fluidity in Lost Foam Casting. It was also found that solidification in the Lost Foam Casting occurs at the metal/foam interface. A heat balance between the molten metal and the mould, and the foam pattern, was developed to give a fluidity equation to aid interpretation of the fluidity results. In summary, this research has provided a better understanding of the effect of casting parameters on the fluidity of Lost Foam Casting and the heat transfer from the molten metal to the foam pattern and to the mould. In addition, the quality of AL alloys castings was improved by reducing the molecular weight of the foam pattern used in the Lost Foam Casting process.
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Edwards, Garren Chad. "Investigation of operating parameters in a vertical stirred mill." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20442.
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Due to the depletion of coarser grained ores, more mineralogically complex ores are being treated. These complex ores usually have finer grained valuable minerals. Liberation of these finer grained valuable minerals lies in grinding finer. Grinding to these fine sizes is energy intensive and using standard ball mills are energy inefficient at these sizes (P80 < 75μm). Therefore, stirred mills are becoming increasingly prevalent in the mineral processing industry. In order to optimize these mills, the effects and mechanisms of the significant variables need to be understood. This project investigated operating parameters against performance in a laboratory scale vertical stirred mill (Deswik mill), in an ultrafine grinding (UFG) application of MG2 reef in the bushveld igneous complex. The operating variables that were investigated are stirrer speed, solids concentration, media size and media filling. The Kwade stress energy model was tested on the grinding results. The grinding performance was quantified in two ways, i.e. grinding efficiency and grinding rate. The grinding performance for this study was also investigated through a statistical analysis. The experiments was designed using a face centred central composite design (FCCD) and the results was statistically analysed using a design of experiments (DOE) software.
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Fiorese, Elena. "Process parameters affecting quality of high-pressure die cast aluminium alloys." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3426773.
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High pressure die casting (HPDC) is a widely used process for manufacturing components with high production rate and complex geometries. However, high pressure die casting is still considered a “defect generating process”, since an amount of 5-10% of scrap is usually detected in castings. For this reason, the availability of new standards and tools for optimizing the process is one of the prominent needs of foundry field.
Both these issues are tackled in this Thesis. First, a new classification of defects and reference dies for estimating the static mechanical properties of aluminium alloys have been developed and then published as CEN Technical Reports, satisfying the need for new standards. Then, a novel and comprehensive methodology has been developed for optimizing HPDC process through the definition of meaningful behavioural models. Some newly defined process parameters have been hence introduced, by representing the most important physical phenomena affecting casting quality and the integral nature of HPDC, and an original approach is outlined. In particular, in order to provide an effective representation of the different process stages, the following parameters have been found to be more influential and effective in representing transmitted forces, mechanical energy exchange and heat removal: the root mean square acceleration in the second stage, the energy associated to the flow forces in the whole cycle, the work of the pressure forces in the third stage and the normalized thermal gradient. The first two parameters embody the plunger motion time-history, the third parameter represents the hydraulic pressure time-history, while the last one concentrates on some thermal aspects. These parameters take advantage from signal processing techniques of the measured position and pressure profiles. Four experimental campaigns (in the whole 210 castings) using different injection machines, different alloys and different geometries of the die have been carried out to validate the novel process parameters and to prove the general validity of the approach.
The statistical correlation with the measured static mechanical properties, density and percentage of porosity, as well as the metallographic analysis (percentage of oxides on fracture surfaces, analysis of different kinds of internal defect) prove the soundness of the developed method.
Given the significance of the plunger motion profile in explaining the casting quality, analytical models for computing the root mean square acceleration and the energy associated to the flow forces have been developed. These analytical models permit selecting in advance the best plunger motion profile, which guarantees reliability and soundness of castings, thus satisfying the need expressed by foundries for effective optimization tools.<br>La pressocolata è un processo ampiamente utilizzato per produrre componenti con elevata produttività e geometria complessa. Comunque, la pressocolata è ancora considerata un “processo generatore di difetti”, dal momento che una percentuale del 5-10% di scarto è rilevata di solito nei getti. Per questa ragione, la disponibilità di nuovi standard e strumenti per l’ottimizzazione di processo è uno dei bisogni più importanti del settore della fonderia.
Entrambe queste criticità sono affrontate in questa Tesi. Per prima cosa, è stata sviluppata e successivamente pubblicata come Report Tecnici riconosciuti dal CEN una nuova classificazione dei difetti e degli stampi di riferimento per stimare le proprietà meccaniche statiche delle leghe di alluminio, rispondendo al bisogno di nuovi standard. Poi, è stata sviluppata una metodologia nuova e completa per ottimizzare il processo di pressocolata attraverso la definizione di metamodelli significativi. Quindi, sono stati introdotti dei nuovi parametri di processo, che rappresentano i più importanti fenomeni fisici che influenzano la qualità dei getti e la natura integrale del processo di pressocolata, ed è stato delineato un approccio originale. In particolare, allo scopo di fornire una rappresentazione efficace delle diverse fasi del processo, si è dimostrato che i seguenti parametri sono i più influenti ed efficaci nel rappresentare le forze trasmesse, il flusso di energia meccanica e l’asportazione del calore: il valore quadratico medio dell’accelerazione in seconda fase, l’energia associata alle forze di flusso nell’intero ciclo, il lavoro delle forze di pressione nella terza fase e il gradiente termico normalizzato. I primi due parametri descrivono l’effetto del profilo di moto del pistone; il secondo è invece legato anche alla pressione esercitata dal pistone stesso, mentre l’ultimo rappresenta esclusivamente fenomeni di natura termica. Lo sviluppo ed il calcolo di questi parametri sfrutta le tecniche di elaborazione numerica dei segnali, al fine di estrarre le informazioni dai profili misurati di posizione e di pressione del pistone.
La validazione del metodo proposto è stata condotta attraverso quattro diverse campagne sperimentali, con un totale di 210 getti analizzati, nelle quali sono state utilizzate diverse macchine di iniezione, diversi stampi e diverse leghe, al fine di ottenere risultati generali ed estendibili.
La correttezza del metodo proposto è confermata dalla correlazione statistica dei parametri proposti con la resistenza meccanica statica, con la densità, la porosità, e da alcune significative analisi metallografiche (percentuale di ossidi sulle superfici di frattura, analisi dei difetti interni).
Data l’efficacia dimostrata dei parametri proposti, ed in particolare di quelli legati al profilo di moto del pistone, l’approccio è stato esteso tramite lo sviluppo di alcune relazioni analitiche per calcolare i due parametri cinematici. Ciò rappresenta uno strumento efficace per sintetizzare a priori il profilo di moto ottimale del pistone che, nel rispetto dei vincoli di macchina, consenta di ottimizzare la qualità dei getti.
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Rojas, Hector E. "The effect of ball mill operating parameters on mineral liberation." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/50084.
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In previous studies, the analysis of ball mill operating parameters and their effects on breakage phenomena has been limited to homogeneous materials. Though these studies have proven to be an asset in predictions of product size distributions and mill scale-up, they have not addressed the primary role of grinding, i.e. liberation.
The present investigation analyzes the effect of ball mill operating parameters on the breakage rates of both liberated and composite material. The operating parameters studied include mill rotational speed, ball size, mill charge, and wet versus dry grinding. Breakage rates have been determined experimentally utilizing a SEM-IPS image analyzer. The mineral sample used was acquired from ASARCO's Young Mine which is located in Jefferson City Tennessee. It was a binary ore consisting of sphalerite and dolomite.
Batch grinding experiments were conducted to provide breakage rates for the various composition classes. Breakage rates were then normalized with respect to energy to see if the changes in breakage rates associated with mill operating parameters were due to changes in breakage kinetics, or simply a function of energy input.
The energy normalized data indicates that the free dolomite breakage rates tend to normalize with respect to energy in the case of varying interstitial fillings. Furthermore, changes in mill rotational speed tend to provide energy normalizable breakage rates for both free dolomite and sphalerite. In all other cases, analysis of the breakage rates and energy-specific breakage rates indicate that a change in breakage kinetics may be occurring.
In general, particles containing a high proportion of sphalerite are more apt to break under impact conditions. On the other hand, particles containing a large proportion of dolomite were found to prefer attrition breakage conditions.<br>Master of Science<br>incomplete_metadata
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Chan, Chee-Wan. "Effects of powered harrow operating parameters on soil physical properties." Connect to resource, 1992. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1200585211.
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McCarty, Michael James. "Determining the Optimum Operating Parameters of a Unipolar PWM Inverter." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/287.
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This study presents a determination of the optimum operating parameters of a unipolar PWM inverter through theoretical and experimental analysis. The inverter is investigated in its simplest form without input DC-DC conversion or output filtering. The intent of this study is to understand the core of the inverter thoroughly before adding peripheral elements such as output filtering. Variations on the input voltage level and switching frequency were investigated to determine their impacts on the operation of the inverter and harmonics produced. Theoretical modeling and calculations confirmed by experimental measurements and analysis allow determination of the inverter operating conditions which allow highest converter efficiency with lowest distortion. Results suggest highest efficiency and lowest harmonic distortion is achieved at the lowest input voltage (just above the peak of the desired fundamental component) and lowest switching frequency independent of output power.
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Lööv, Simon. "Comparison of Undersampling Methods for Prediction of Casting Defects Based on Process Parameters." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-20596.
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Prediction of both big and small decisions is something most companies have to make on a daily basis. The importance of having a highly accurate technique for different decision-making is not something that is new. However, even though the importance of prediction is a fact to most people, current techniques for estimation are still often highly inaccurate. The consequences of an inaccurate prediction can be huge in the differences between the misclassifications. Not just in the industry but for many different areas. Machine learning have in the recent couple of years improved significantly and are now considered a reliable method to use for prediction. The main goal of this research is to predict casting defects with the help of a machine-learning algorithm based on process parameters. In order to achieve the main goal, some sub-objectives have been identified to successfully reach those goals. A problem when dealing with machine learning is an unbalanced dataset. When training a network, it is essential that the dataset is balanced. In this research we have successfully balanced the dataset. Undersampling was the method used in our research to establish our balanced dataset. The research compares and evaluates a couple of different undersample methods in order to see which undersampling is best suited for this project. Three different machine models, “random forest”, “artificial neural network”, and “k-nearest neighbor”, are also compared to each other to see what model performs best. The conlcusion reached was that the best method for both undersampling and machine learning model varied due to many different reasons. So, in order to find the best model with the best method for a specific job, all the models and methods need to be tested. However, the undersampling method that provided best performances most times in our research was the NearMiss version 2 model. Artificial Neural Network was the machine learning model that had most success in our research. It performed best in two out of three evaluations and comparisons.
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Notton, David. "Theoretical and experimental determination of key operating parameters for composting systems." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/54547/.
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The combination of increasing quantities of Municipal Solid Waste (MSW) and increased legislation for the disposal of this type of waste have created a need to develop different disposal or treatment routes for waste. Approximately 60% of MSW by mass is biodegradable and many disposal routes for this waste allow energy recovery. However the waste hierarchy presented in the National Waste Strategy for Wales emphasises the importance of materials recovery over energy recovery. It has been shown that the only way to achieve these targets is through the recovery of catering waste, which requires an in-vessel composting facility. In order to gain an insight into the aeration requirements for in-vessel composting, calculations were performed to ascertain the required airflow for the supply of oxygen, the removal of excess moisture and the removal of excess heat. It was found that approximately 450kJ are released for each mole of oxygen utilised whilst 500kJ are released per mole of carbon dioxide evolved. It was found that the air requirement for removal of heat from the process was approximately 100 times greater than the air required to supply oxygen to the system. In order to determine the power of aeration equipment required for composting facilities a static pressure test rig was constructed. From the results gained a model relating the static pressure to the bulk density of compost was developed. Initially a windrow composting system processing green waste at the Carmarthenshire Environmental Resources Trust (CERT) composting facility was studied. A canopy system was developed to monitor the respiration rate of this system and allow comparison between different feedstocks and control strategies. For a green waste only windrow the highest recorded respiration rate was 38gC02kgVS"1day"1. The respiration rate was observed to reduce with temperature above 55 °C. In addition to the green waste windrows a temperature managed windrow and a windrow constructed from a mixture of green waste and chicken litter were also tested. The final series of trials involved the testing of the ability of a containerised composting system to meet the Animal By-Products Regulations. The vessel was fed various mixtures of green waste and factory waste. Airflow and insulation within the vessel were analysed and a composting rate of over 45gC02kgVS'1day1 was achieved. If this had been sustained then the vessel may have met the Animal By-Products Regulations.
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Ebermann, Marko. "Influence of geometric form deviations on operating parameters in hydrodynamic bearings." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21225.
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Hydrodynamic plain bearings are important machine elements. They are used in many areas of mechanical engineering, such as turbomachines, crankshaft bearings and gears. The geometry of the lubrication gap elemen-tarily influences the function as shown in several examples of abrupt failures in turbochargers. Due to toleranc-ing, the manufacturing requirements are very high. However, the question remains how large these deviations can be. ISO 12129-2 gives recommendations on form deviations depending on the minimum of plain bear-ing clearance (hmin). Nevertheless, there is no direct reference on the size or the strain on bearing. In DIN 31652-3, the tolerance of the bearing clearance is divided into -1/3 and +2/3 of itself. However, this tolerance merely has an indirect correlation with the size of the bearing and strain on the bearing. If these tolerance recommenda-tions are applied, the function of the plain bearing will not be completely fulfilled. Nonetheless, tolerances pro-vided by standards are used in geometric specifications. If these tolerances are used for in-company manufacturing, this is unproblematic in most cases. But if technical drawings are sent to an external manufacturer, toler-ance limits may be exhausted and the function cannot be ensured.
Within the framework of the research project presented here, a tolerance evaluation matrix has been developed. For this, the existing standards were analyzed. In this case, the ignorance of size (diameter and width) and signif-icant operating properties (speed, load, temperature, etc.) are insufficient. The project examined and simulated various possible deviations. Selected form deviations were manufactured. The validation of the simulation results were carried out on 30mm.
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Ang, Yang Adrian. "Prediction and analytics of operating parameters on thermoelectric generator energy generation." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3872.
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The efficient use of energy at all stages along the energy supply chain and the utilization of renewable energies are very important elements of a sustainable energy supply system, specially at the conversion from thermal to electrical energy. Converting the low-grade waste heat into electrical power would be useful and effective for several primary and secondary applications. One of the viable means to convert the low-grade waste heat into electrical energy is the use of thermoelectric power conversion. The performance of thermoelectric generators, subjected to thermal effects, can vary considerably depending on the operating conditions, therefore it is necessary to measure and have a better understanding of the characteristics and performance of the thermoelectric generator. It is important to understand the thermoelectric generator’s dynamic behavior and interaction with its operating environmental parameters. Based on this knowledge, it is then significant to develop an effective mathematical model that can provide the user with the most probable outcome of the output voltage. This will contribute to its reliability and calculation to increase the overall efficiency of the system. This thesis provides the transient solution to the three-dimensional heat transfer equation with internal heat generation. It goes on to describes the transfer and generation of heat across the thermoelectric generator with dynamic exchange of heat. This solution is then included in a model in which the thermal masses and the operating environmental parameters of the thermoelectric generator are factored in. The resulting model is created in MATLAB. The comparison with experimental results from a thermoelectric generator system confirms the accuracy of the artificial neural network model. This thesis also presents two practical applications, the prediction of the input parameters with a given output voltage, and sensitivity analysis designed for the model. This is to enable users to customize the thermoelectric generator for their requirements. This allows for better usage of resources eventually.
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Acar, Joseph 1977. "Effect of engine operating parameters and fuel characteristics on diesel engine emissions." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30319.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.<br>Includes bibliographical references (leaf 32).<br>To examine the effects of using synthetic Fischer-Tropsch (FT) diesel fuel in a modern compression ignition engine, experiments were conducted on a MY 2002 Cummins 5.9 L diesel engine outfitted with high pressure, common rail fuel injection, a variable geometry turbo charger, cooled EGR and a fully configurable engine management computer. Additionally, the effect of varied injection timing and EGR rates were studied to examine how the engine can be optimized for FT fuel. The test fuels included two standard diesel fuels, one with 400 PPM sulfur content and the other 15 PPM sulfur. The experimental fuels were Syntroleum Corporation's S-1 fuel, as well as blends of 25% S-1 with a balance of 15 or 400 PPM D2. Tests were conducted with three engine operating conditions: 1682 RPM, 474 kPa BMEP; 2011 RPM, 1000 kPa BMEP; 2011 RPM, 1400 kPa BMEP. It was found that FT fuel reduced NOx emissions 19% in low load tests, but alone had little effect in higher load tests. FT fuel reduced particulate matter (PM) emissions in almost all test case, on the order of 25 to 75%. Retarding injection timing and increasing EGR both reduce NOx emissions. In the case of standard fuels, these reduction come at the expense of increased PM. However, FT fuel reduced this effect and allows for more retarded timing and further increased EGR rates to control NO. Blended fuels, containing 25% FT, by volume, and a balance of 15 PPM or 400 PPM fuel, were found to provide most of the benefit of straight FT fuel. The FT/15 blend reduced PM 40% and the FT/400 blend reduced PM 60%.<br>by Joseph Acar.<br>S.M.
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Feng, Ming-Fa. "Fault diagnosis and prediction in reciprocating air compressors by quantifying operating parameters." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39786.
Full textAbstract:
This research introduces a new method of diagnosing the internal condition of a reciprocating air compressor. Using only measured load torques and shaft dynamics, pressures, temperatures, flow rates, leakages, and heat transfer conditions are quantified to within 5%.
The load torque acting on the rotor of the machine is shown to be a function of the dynamics (instantaneous position, velocity, and acceleration) of the driving shaft, the kinematic construction, and the internal condition of the machine. If the load torque, the kinematic construction of the machine, and the dynamics of the rotor are known, then the condition of the machine can be assessed.
A theoretical model is developed to describe the physical behavior of the slider-crank mechanism and the shaft system. Solution techniques, which are based on the machine construction, crankshaft dynamics, and load torque measurements, are presented to determine the machine parameters. A personal computer based system used to measure the quantities necessary to solve for the machine parameters and the quantities used to compare with calculations is also documented.
The solution algorithm for multi-stage compressors is verified by decoupling the load torque contributed by each cylinder. Pressure data for a four-stage two-cylinder high pressure air compressor (HPAC) is used. Also, the mathematical model is proven feasible by using measured angular velocity of the crankshaft and direct measurements of the load torque of a single stage, single cylinder air compressor to solve for the machine parameters.
With this unintrusive and nondestructive method of quantifying the operating parameters, the cylinder pressures, operating temperatures, heat transfer conditions, leakage, and power consumption of a reciprocating air compressor can be evaluated.<br>Ph. D.
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Das, Suma Rani. "Investigation of Design and Operating Parameters in Partially-Filled Rubber Mixing Simulations." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1479151141596147.
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Vedantham, Kumar. "Effect of operating parameters on the growth rate of solution grown crystals." Master's thesis, Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-07122004-101317.
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Nikiema, Sompassaté Josiane. "Attenuation of greenhouse gas emissions by means of methane biofiltration optimization of the operating parameters." Thèse, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1911.
Full textAbstract:
The main goal of this work has been that of optimizing the operating conditions of a biofilter, intended for the control of methane, an important greenhouse gas widely emitted by older or smaller landfill installations.The specific objectives were: (1) to select a suitable packing material (of organic or inorganic type); (2) to optimize the concentrations of input nutrients, mainly consisting of nitrogen, phosphorus, potassium and copper, which are intended to be introduced via the nutrient solution; (3) to determine the optimized values of the most important design parameters, such as the methane inlet load (which depends on the air flow rate and the inlet methane concentration); and (4) to model the biofilter performance. Firstly, the comparison of the two packing materials, one of organic type, and the other of inorganic type, has revealed that the latter was the more appropriate material for the methane biofiltration. Then, through the use of the selected packing material, the influence of each individual nutrient on the efficiency of the process has been investigated.The results obtained have shown that both nitrogen and phosphorus concentrations have to be controlled, while potassium and copper were revealed as being nutrients of only minor importance. Secondly, the optimization of the inlet gas flow rate and of the inlet methane concentration (and consequently, of the methane inlet load also), has been performed. According to the results of the studies, these parameters require good control during methane biofiltration because a limitation in biofilter performance could otherwise be induced. In addition, it was noted that the increase in the inlet gas flow rate led generally to a greater decrease of the methane conversion than the one induced by the inlet methane concentration. Finally, a new method, based on the use of solid extracts sampled from the methane biofilter, has been applied to the determination of methane biofilter kinetic parameters. Following this study, a steady state model of the methane biofiltration, taking into consideration the important operational parameters, as identified previously, has been developed. One particular feature of this model is that it takes into consideration the influence of the biofilter average temperature.The prediction results, obtained with the use of the model, have been successfully compared with the experimental results.
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Oral, Edibe Eda. "Effect Of Operating Parameters On Performance Of Additive/ Zeolite/ Polymer Mixed Matrix Membranes." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612957/index.pdf.
Full textAbstract:
Membrane based separation techniques have been widely used and developed over
decades. Generally polymeric membranes are used in membrane based gas
separation<br>however their gas separation performances are not sufficient enough for
industrial feasibility. On the other hand inorganic membranes have good separation
performance but they have processing difficulties. As a consequence mixed matrix
membranes (MMMs) which comprise of inorganic particles dispersed in organic
matrices are developed. Moreover, to enhance the interaction between polymer and
zeolite particles ternary mixed matrix membranes are introduced by using low
molecular weight additives as third component and promising results were obtained
at 35 °<br>C. Better understanding on gas transport mechanism of these membranes
could be achieved by studying the effect of preparation and operating parameters.
This study investigates the effect of operation temperature and annealing time and
temperature on gas separation performance of MMMs. The membranes used in this
study consist of glassy polyethersulfone (PES) polymer, SAPO-34 particles and 2-
v
hidroxy 5-methyl aniline (HMA) as compatibilizer. The membranes fabricated in
previous study were used and some membranes were used as synthesized while
post annealing (at 120°<br>C, 0.2atm, N2 atm, 7-30 days) applied to some membranes
before they are tested. The temperature dependent gas transport properties of the
membranes were characterized by single gas permeation measurements of H2, CO2,
and CH4 gases between 35 °<br>C-120 °<br>C. The membranes also characterized by
scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and
differential scanning calorimetry (DSC).
Annealing time and temperature affected the reproducibility and stability of the
mixed matrix membranes and by applying post annealing step to mixed matrix
membranes at higher temperatures and longer times, more stable membranes were
obtained. For pure PES membranes thermally stable performances were obtained
without any need of extra treatment.
The permeabilities of all studied gases increased with increasing operation
temperature. Also the selectivities of H2/CO2 were increased while CO2/CH4, H2/CH4
selectivities were decreased with temperature. The best separation performance
belongs to PES/SAPO-34/HMA mixed matrix membrane at each temperature. When
the temperature increased from 35 °<br>C to 120 °<br>C H2/CO2 selectivity for PES/SAPO-
34/HMA membrane was increased from 3.2 to 4.6 and H2 permeability increased
from 8 Barrer to 26.50 Barrer. This results show that for H2/CO2 separation working
at higher temperatures will be more advantageous. The activation energies were
found in the order of<br>CH4 ><br>H2><br>CO2 for all types of membranes. Activation energies
were in the same order of magnitude for all membranes but the PES/SAPO-34
membrane activation energies were slightly lower than PES membrane.
Furthermore, PES/SAPO-34/HMA membrane has activation energies higher than
PES/SAPO-34 membrane and is very close to pure membrane which shows that
HMA acts as a compatibilizer between two phases.
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Giffin, Amanda. "Investigation of Operating Parameters Influencing Electrostatic Charge Generation in Gas-Solid Fluidized Beds." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19728.
Full textAbstract:
Electrostatic charge generation in gas-solid fluidized beds is a significant industrial problem. Associated problems include particle agglomeration and particle wall fouling. In the polymerization industry this may result in "sheets" of fused polymer, due to exothermic reaction causing the melting of the polymer, which can fall off and block the distributor plate disrupting fluidizing gas flow. Additionally, blockage of the catalyst feed or the polymer removal system can take place or the product can become non-uniform. All of these problems require shut-down of the reactor which results in lost production time. While this phenomena has been identified for many years, the mechanisms involved are not well understood, especially wall fouling and the distribution of charge within the bed. Isolation of individual parameters such as hydrodynamics, operating conditions, and material involved is necessary to evaluate how each parameter impacts charge generation during fluidization.
In this thesis, the fluidization system consisted of a stainless steel column, two online Faraday cups, and a retractable distributor plate. This system allowed for the simultaneous measurement of charge within different regions of the bed: the entrained fine particles, the particles adhered to the column wall, and the bulk of the bed. Additionally, mass and particle size distributions were measured and images of the layer of particles adhered to the column wall were taken for comparison. This allowed for a charge distribution comparison and evaluation of wall fouling.
Three different parameters were investigated: duration of fluidization, column wall material, and relative humidity of fluidizing gas. Fluidization time was studied for 15, 30, 60, 120, 180, and 360 min; relative humidity was investigated for 0%, 20%, 40%, 60%, and 80% relative humidity. Both fluidization time and relative humidity were evaluated at four different fluidization gas velocities, two each in the bubbling and slugging flow regimes. Column wall material was evaluated for a stainless steel and carbon steel column at two gas velocities, one each in the bubbling and slugging flow regimes.
Fluidization time was found to influence wall fouling in the bubbling flow regime as the particle layer continued to build as fluidization progressed. In the slugging flow regime, the particle layer developed within 15 minutes of the onset of fluidization. The bubbling flow regime was shown to have a greater capacity for charge generation than the slugging flow regime. This was due to the vigorous mixing in the bubbling flow regime resulting in more particle-particle interactions.
Column wall material was shown to influence wall fouling in the slugging flow regime due to the differences in surface roughness of the columns. This was due to the particle-wall contacts resulting in frictional charging which is the predominant charging mechanism in this flow regime. Charge was also impacted in the bubbling flow regime in those particles that were adhered to the column wall.
Relative humidity was found to influence wall fouling at the lowest gas velocity tested. However, variations in generation of charge occurred at all fluidization gas velocities tested; the charge-to-mass ratios for the particles adhered to the column wall in the slugging flow regime decreased with high relative humidities. This was due to either the formation of a water film layer on the column wall or instantaneous surface water films on the particles throughout fluidization.
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Baqqar, Mabrouka. "Machine performance and condition monitoring using motor operating parameters through artificial intelligence techniques." Thesis, University of Huddersfield, 2015. http://eprints.hud.ac.uk/id/eprint/28315/.
Full textAbstract:
Condition monitoring (CM) of gearboxes is a necessary activity due to the crucial importance of gearboxes in power transmission in most industrial applications. There has long been pressure to improve measuring techniques and develop analytical tools for early fault detection in gearboxes. This thesis develops new gearbox monitoring methods by demonstrating that operating parameters (static data) obtained from machine control processes can be used, rather than parameters obtained from vibration and acoustic measurements. Such a development has important implications for the future of CM techniques because it could greatly simplify the measurement process. To monitor the gearbox under different operating and fault conditions based on the static data, three artificial intelligence (AI) techniques: a general regression neural network (GRNN), a back propagation neural network (BPNN), and an adaptive neuro-fuzzy inference system (ANFIS) have been used successfully to capture nonlinear variations of the electric motor current and control parameters such as load settings and temperatures. The three AI systems are taught the expected values of current; load and temperature for the gearbox in a given condition, and then measured values obtained from the gearbox with a known fault introduced are assessed by each of the AI models to indicate the presence of this abnormal condition. The experimental results show that each of GRNN, BPNN and ANFIS are adequate and are able to serve as an effective tool for gearbox condition monitoring and fault detection. The main contributions of this study is to examine the performance of a model based condition monitoring approach by using just operating parameters for fault detection in a two stage gearbox. A model for current prediction is developed using an ANFIS, GRNN and BPNN which captures the complicated inter-relations between measured variables, and uses direct comparison between the measured and predicted values for fault detection.
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BORGSTROM, MARK CRAIG. "ESTIMATION OF RECEIVER OPERATING CHARACTERISTIC (ROC) CURVE PARAMETERS: SMALL SAMPLE PROPERTIES OF ESTIMATORS." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184127.
Full textAbstract:
When studying detection systems, parameters associated with the Receiver Operating Characteristic (ROC) curve are often estimated to assess system performance. In some applied settings it is often not possible to test the detection system with large numbers of stimuli. The resulting small sample statistics many have undesirable properties. The characteristics of these small sample ROC estimators were examined in a Monte Carlo simulation. Three popular ROC parameters were chosen for study. One of the parameters was a single parameter index of system performance, Area under the ROC curve. The other parameters, ROC intercept and slope, were considered as a pair. ROC intercept and slope were varied along with sample size and points on the certainty rating scale to form a four way factorial design. Several types of estimators were examined. For the parameter, Area under the curve, Maximum Likelihood (ML), three types of Least Squares (LS), and Distribution Free (DF) estimators were considered. Except for the DF estimator, the same estimators were considered for the parameters, intercept and slope. These estimators were compared with respect to three characteristics: bias, efficiency, and consistency. For Area under the curve, the ML estimator was the least biased. The DF estimator was the most efficient, and all the estimators except the DF estimator appeared to be consistent. For intercept and slope the LS estimator that minimized vertical error of the points from the ROC curve (line) was the least biased for both estimators. This LS estimator was also the most efficient. This estimator along with the ML estimator also appeared to be the most consistent. The other two estimators had no significant trend toward consistency. These results along with other findings, illustrate that different estimators may be "best" for different sample sizes and for different parameters. Therefore, researchers should carefully consider the characteristics of ROC estimators before using them as indices of system performance.
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Gungor, Ergin. "Investigation Of Parameters Affecting The Drying Rate Of Sanitary Wares." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606649/index.pdf.
Full textAbstract:
The influence of drying parameters namely residence time before drying, drying temperature, drying time, relative
humidity, and slip recipe on the drying rate of
slip cast sanitary wares, predominantly lavatories and toilet closets, was studied.
The drying temperatures were changed from 80 oC to 110 oC with an increment of 10 oC. The drying time was changed from 10 to 7 h with a decrease of 1 hour. Relative humidity of the environment was changed from 60 to 75 %. The percent
weight loss, percent residual moisture and the percent shrinkage of the samples were determined by weighing and measuring the samples before and after the tests. The percent weight loss was within the range of 6.5 to 6.6 % after holding the as cast samples for 6 hours at ambient casting shop conditions while it was within the range of 17.96 to 18.10 % when subsequently dried for 10 hours at 110
oC in the dryer. The percent shrinkage was within the range of 2.9 - 3.0 % after holding the as cast samples 6 h at ambient laboratory conditions. No shrinkage was observed in the sample when it was subsequently dried for 10 hours at 110 oC in the dryer.
Optimum moisture content of dried wares was obtained after drying for 8 hours at 100 oC in the dryer. It has been seen that the relative humidity of the dryer at the beginning of the drying should be lower than 75 %. As the non-plastic content in the recipe of the sanitary ware slip increased, drying shrinkage and residual moisture content decreased.
The results of this study showed that through increasing the residence time up to 6h with a casting shop environment of approximately 30 oC and 60 % relative humidity, the drying time could be safely reduced from 10 h to 8 h with a drying
temperature of 100 oC for the test plates. The same approach can be used for more complex shapes, e.g., WC closets, basins, tanks etc. in EczacibaSi Vitra plant. Once the drying time was reduced, the amount of natural gas per ware would be reduced to a certain extent. Aside from that the reduction in the drying time would increase the quantity of the drying cycles per week so that more wares could be dried.
When all these observations were taken into account, this thesis study could also be utilized by other sanitary ware producing companies whose processes require slip cast drying.
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Adane, Tigist Fetene. "Mapping Energy Usage in Casting Process for Cylinder Head Production : Using System Dynamic Modeling and Simulation." Thesis, KTH, Industriell produktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122459.
Full textAbstract:
Daily life of our societies is strongly linked with the usage of natural resources. However, the vital resources of our planet especially energy is a limited resource. The energy consumption in the manufacturing industry is increasing and becoming noticeable; moreover it is being consumed in ways that can’t be sustained. There is great concern about minimizing the consumption of energy usage in the manufacturing industry and sustaining the natural carrying capacity of the ecosystem as well. This is one of the important challenges in today’s industrial world. This research work looks into one of the energy intensive manufacturing processes i.e. the casting process in automotive industry. Here the casting process for cylinder head manufacturing at one of the manufacturing plant in Europe is studied for identifying the most energy intensive steps namely melting, holding and pouring. Parameters that influence these steps and the relationships for energy consumption and dissipation have also been identified through extensive literature survey. By applying system dynamics modeling and simulation approach the interaction between each parameter in the overall process is analyzed in regard to energy consumption. By varying values of the parameters that have the highest impact in the process, the breakthrough opportunities that might dramatically reduce energy consumption during melting and holding have been explored, and potentially energy-saving areas based on the findings have also been identified. The output from this research work enables the company to identify potential avenues to optimize energy usage in the production and hence sustain its manufacturing.
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Moughrabiah, Wajeeh O. "Effect of operating parameters and particle properties on electrostatics in gas-solid fluidized beds." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12867.
Full textAbstract:
The influences of operating pressure, temperature and gas velocity on electrostatics in a fluidized bed of glass beads and different grades of polyethylene resin were investigated in a fluidization column of 150 mm inner diameter and 2.0 m height. Eight collision probes at different levels and radial positions measured the electrostatics in the bed. The electrostatics increased as pressure increased, probably due to an increase in bubble rise velocity, frequency and volume fraction. As the pressure increased, particle-particle and particle-wall collisions near the distributor and wall contributed heavily to charge generation. Temperature also played a role. At higher temperatures (up to 90°C), the polarity of net cumulative charge in the bed reversed. As the superficial gas velocity increased, the electrostatics increased. However, at higher gas velocities, the polarity in the freeboard was opposite to that in the bed, indicating that fines entrained from the column carried charges, resulting in a net charge of opposite polarity to that inside the bed.
For Geldart group B particles the degree of electrification in the bed slightly increased with decreasing particle size. Charging for group A particles was significantly greater than for group B particles. For binary mixtures of group A and B particles the electrostatics increased as the proportion of small particles increased.
As the relative humidity (RH) of fluidizing air increased, the electrostatics decreased. For the RH range (5-30%) explored, the sensitivity of the charging to RH varied significantly depending on the location of the probes.
As the proportion of fine glass beads (<30 µm) increased to 2.0 wt% in a fluidized bed of large glass beads (574 µm), the electrostatics in the bed decreased, likely because the fines acted as spacers between larger particles.
The electrostatics decreased as the proportion of an antistatic agent (Larostat) increased from 0.0 to 0.5 wt%, because Larostat tends to adsorb moisture and attach to the surface of the glass beads, consequently enhancing their surface conductivity. However, the degree of electrification increased when the wt% of Larostat exceeded 1.0%, likely due to the tendency of Larostat particles to adsorb water and to agglomerate.
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Gambrill, Richard. "The sensitivity of diesel engine performance to fuel injection parameters at various operating points." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/11253/.
Full textAbstract:
This thesis describes research undertaken to establish the advantages and disadvantages of using high pressure common rail fuel injection systems with multiple injection capabilities. The areas covered are detailed as follows. Oscillations in the rail pressure due to the opening of the injector can affect the quantity of fuel injected in subsequent injection events. The source of these oscillations has been investigated. A method of damping or reducing the oscillations has been defined and was applied. This successfully reduced the level of unpredictability of the quantity of injected fuel in subsequent injection events. A relationship between needle lift, injection pressure and the quantity of fuel injected was established. The effects of fuel injection parameters (main injection timing, split main separation and ratio) and engine operating parameters (boost pressure and EGR level) on emissions formations and fuel economy have been investigated at five operating points. Design of Experiments techniques were applied to investigate the effect of variables on pollutant emissions and fuel consumption. The sensitivity and linearity of responses to parameter changes have been analysed to assess the extent to which linear extrapolations will describe changes in smoke number (FSN) and oxides of nitrogen (NOx); and which parameters are the least constricting when it comes to adjustments of parameter settings on the FSN-NOx map. Comparing results for split main and single injection strategies at the five operating conditions shows that split main injection can be exploited to reduce NOx or FSN values at all conditions and both NOx and FSN simultaneously at high load conditions. The influence of changing engine speed and brake mean effective pressure (BMEP) on FSN and NOx emissions with given fixed values of parameter settings has been investigated. This established how much of the operating map could be covered by discrete calibration settings. Finally the variation in parameter settings required to maintain fixed FSN and NOx values across the operating map, near the optimum trade-off on the FSN-NOx map, was analysed. Combining the information gained from the individual investigations carried out highlighted some techniques that can be used to simplify the calibration task across the operating map, while also reducing the amount of experimental testing required.
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Su, Chaoran. "Influence of lead impurity and manganese addition on main operating parameters of zinc electrowinning." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27769.
Full textAbstract:
L'influence des ions Pb2+ sur le dépôt de zinc a été étudiée dans l'électrolyte acide de sulfate de zinc avec et sans Mn2+. La polarisation galvanostatique, la polarisation potentiodynamique, la voltammétrie cyclique (VC), les mesures de bruit électrochimique (MBE) et la spectroscopie d'impédance électrochimique (SIE) en conjonction avec la microscopie électronique à balayage (MEB) et la diffraction des rayons-X (XRD) ont été considérés. L'effet de différents paramètres de fonctionnement tels que la concentration de Zn2+, la concentration d’acide sulfurique, la densité de courant, l'agitation de l’électrolyte et la température a été étudié en présence de Mn2+ et Pb2+. Les résultats galvanostatiques utilisant un électrolyte standard de zinc contenant 12 g/L de Mn2+ (ES) ont montré que les ions de plomb ajoutés à l’ES conduisaient à une augmentation du potentiel cathodique et de l'efficacité de courant (EC) du dépôt de zinc. L'augmentation de la concentration de Mn2+ dans l'électrolyte a entraîné une diminution du potentiel cathodique et d’EC du dépôt de zinc à cause de l'effet de dépolarisation du MnO4- formé. En outre, l'augmentation de la densité de courant de 45 à 60 mA/cm2 et de l'agitation de 60 à 412 tr/min ont donné lieu à une augmentation du potentiel et à une diminution d’EC. L'augmentation de la température de 35 à 45°C a conduit à une diminution du potentiel cathodique. Pour l'électrolyse de longue durée (72 h), la teneur de Pb dans le dépôt de zinc en utilisant l'anode Pb-0,7%Ag était de 1,90-1,98 ppm, presque équivalente à celle employant l'anode de Pt avec l’addition de 0,15-0,2 mg/L de Pb2 +. L'électrolyse à 40°C et 52,5 mA/cm2 en présence de plomb jusqu'à 0,1-0,2 mg/L dans un électrolyte contenant 12 g/L Mn2+ pourrait être considérée comme des meilleurs paramètres opérationnels pour le procédé d'extraction électrolytique. Les études SIE ont montré que le dépôt de zinc sur le zinc est plus facile que celui du zinc sur l'aluminium. L’analyse des MBE a révélé que l'augmentation des concentrations de Pb2+ (0,05-0,8 mg/L) dans l'électrolyte de zinc sans Mn2+ s'accompagne d'une diminution de l'inclinaison et d'une augmentation des valeurs du kurtosis qui puissent être corrélées à la morphologie du dépôt de zinc.<br>The influence of Pb2+ ions on zinc deposition was investigated in acidic zinc sulfate electrolyte with and without Mn2+ ions. Galvanostatic polarization, potentiodynamic polarization, cyclic voltammetry (CV), electrochemical noise measurements (ENM) and electrochemical impedance spectroscopy (EIS) in conjunction with scanning electron microscopy (SEM) and X-ray diffraction (XRD) have been considered. Effects of different operating parameters such as Zn2+ ions concentration, sulfuric acid concentration, current density, electrolyte agitation and temperature were investigated in presence of Mn2+ and Pb2+ ions. The galvanostatic results using standard zinc electrolyte containing 12 g/L Mn2+ (SE) showed that lead ions added to the SE led to an increase in the cathodic potential and current efficiency (CE) of zinc deposit. Increasing Mn2+ concentration in the electrolyte resulted in decrease of cathodic potential and CE of zinc deposit due to the depolarization effect of formed MnO4-. In addition, increases of current density from 45 to 60 mA/cm2 and agitation from 60 to 412 rpm resulted in an increase of overpotential and decrease of CE. Increase of temperature from 35 to 45°C led to a decrease of cathodic potential. For long time electrolysis (72 h), the Pb content in zinc deposit using Pb-0.7%Ag anode was 1.90-1.98 ppm, almost equivalent to that employing Pt anode with addition of 0.15-0.2 mg/L of Pb2+. Electrolysis at 40°C and 52.5 mA/cm2 in presence of lead up to 0.1-0.2 mg/L in an electrolyte containing 12 g/L of Mn2+ could be considered as best conducted operating parameters for electrowinning process. EIS studies showed that zinc deposition on zinc is easier than that of zinc on aluminum. ENM revealed that increase of Pb2+ concentration (0.05-0.8 mg/L) in zinc electrolyte without Mn2+ is accompanied with a decrease of skew and increase of kurtosis values that could be correlated to the morphology of zinc deposit.
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BARNALA, PUKHRAJ K. "Optimization of Operating Parameters of a Material Recovery Facility using Lean Six Sigma Techniques." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321575835.
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Nathoo, Jeeten. "Optimisation of electrolyte composition and operating parameters for the electropolishing of 304 stainless steel." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5430.
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Venkatesan, Krishnan. "Experimental and Numerical Investigation of The Effect of Process Parameters on The Erosive Wear of Die Casting Dies /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487931512619589.
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Saini, Sunil. "Bioreactor for the production of tissue engineered cartilage : defining operating parameters for optimal construct growth." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/10226.
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Man, Kayiu. "Investigations of operating parameters on controlled auto-ignition combustion in a four stroke gasoline engine." Thesis, Brunel University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429235.
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Rhodes, Darren P. "The sensitivity of noise in the community to changes in aircraft design parameters and operating practices." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/27110.
Full textAbstract:
Environmental factors, such as noise and emissions have begun to play a significant role in the design of new aircraft. Although advances in propulsion technology have reduced source noise levels significantly over the past few decades, it is becoming increasingly difficult to project similar advances for the next few decades. It is likely however that some noise benefits may come from improvements in aircraft performance and from changes in operational procedures. In order for such developments to be analysed at the conceptual design stage, an integrated conceptual aircraft design and aircraft noise model is required that enables the designer to rapidly assess the effect of key design parameters on reference noise levels and noise contour area.
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Shabo, Daniel Joseph. "Evaluation of operating parameters for chillers, cooling towers, and air-handlers in a large commercial building." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17848.
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Huang, Bo-Zhi, and 黃柏智. "Evaluation on the Effect of Casting and Metallurgical parameters on the A356 Alloy Casting by Using the Pep-Set Casting Process." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/38188856322773175537.
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碩士<br>逢甲大學<br>機械工程學所<br>91<br>This research investigated the effects of casting parameters ( addition amount of resin and hardener, grain size, PH value and moisture content of the raw material sand, etc. ) and metallurgical parameters (modification , refining of grain, degassing condition, melting temperature, etc. ) on the sand mold properties ( shear strength, permeability ) and the casting qualities ( surface quality, tensile strength, elongation) of the A356.2(Al-Si-Mg) alloy casting produced by Pep-Set casting process. The experimental results are as follows:
For casting parameters, when using 30 mesh silica sand with over 1% resin, over 0.6% hardener, 0% moisture content, PH value of 7 of the raw material sand, and 40 minutes holding time after molding, we can obtain sand mold with good properties. And then the A356.2(Al-Si-Mg) alloy casting after poured also had good properties and with average surface roughness of 14.34μm. Under the same casting parameters, but using 100 mesh sand, the A356.2(Al-Si-Mg) alloy casting after poured will have better surface quality(average surface roughness is 10.91μm) but with worse properties of sand mold. Besides, it is worthy to notice that moisture content and PH value of the raw material sand can influence the properties of Pep-Set sand mold very much. When moisture content is over 0.2%, shear strength of sand mold will decrease clearly. It also will decrease shear strength of sand mold, when raw material sand property became acid.
For metallurgical parameters, strontium modification can increase the tensile properties (tensile strength, elongation). When Sr content is 0.02wt%, the A356.2 alloy casting will have the best tensile properties. Excess Sr (over 0.02 wt%) will promote the formation of intermetallic compound (Al4SrSi2 and Al2SrSi2) and reduce the modification effects and coarsen the eutectic silicon, so that it leads to decrease the tensile strength and elongation. So, the optimum Sr content for A356.2 alloy casting is within the range of 0.02~0.03%. The addition of grain-refiner (Al-5Ti-B) can decrease the grain. As a result, a metallographic microstructure with fine grain size can improve mechanical properties. However, Excess Ti (over 0.2 wt%) will make the grain size refining steadily and increase the intermetallic compound (TiAl3) so that it leads to decrease the elongation. So, the optimum Ti content for A356.2 alloy casting is within the range of 0.15~0.25%. In addition, the effect of degassing will influence the quality of A356.2 alloy casting seriously and the better degassing effect will reduce the gas hole defect etc.. If melting temperature is higher, the gas absorption is more so that it will reduce the density and tensile property of the A356.2 alloy casting.
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Lin, Yung-Ful, and 林永富. "Study of Processing and Optimal Operating Parameters." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/43077896625611932784.
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碩士<br>國立臺灣海洋大學<br>機械與機電工程學系<br>95<br>For the recent year，people have already known the importance of the resource and reuse of organic waste，especially the boosting and implement of reusing the kitchen waste。For the present，the government are boosting the policy of recycle the organic waste and compost。The study of the dissertation is about designing a small scale of kitchen waste equipment by Anaerobic Digestion and discussing the characteristics of the stuff by different parameter。By the coercive implement of the government，the recycling of organic waste has further development。The Kitchen waste compost and feedstuff will increase intensively。Therefore，promote the efficient of the producing procedure and reduce the fee is the key to boost and execute。According to the experiment，the average cost of the depletion electric power reaches at 14.86 NT dollars per kilogram and the average weight of the kitchen waste produces 158.38 kilogram per ton。The main technology of organic waste resource lies in selecting the apparatus and appropriate operation，and by good planning and designing，we can achieve the purpose of reducing and reusing the waste。
Keyword：oragnic wastes、compost、kitchen waste、thermophilic anaerobic digestion
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Fan, Chin-Yu, and 范今瑀. "Optimization of Operating Parameters for Stripper Recycle System." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/59699603733174246425.
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碩士<br>國立中興大學<br>化學工程學系所<br>105<br>The purpose of this research is to find out the major controllable factors for the Stripper Recycle System of an opto-electronic fab. According to the result of the full factorial experiments, the optimization of operating can be estimated.
The experiments included parameter adjustment as well as the cost-effectiveness analysis. The results pointed out that flow rate of feed, steam pressure, rotation speed are the major controllable factors. Based on Thin Film Evaporator of SRS, the results of the eighteen groups of experiments revealed that the significance of influence is in the order of rotation speed＞steam pressure＞feed flow. As for the full factorial experiment, the optimal values of controllable factors are feed flow kept at 160 L/hr, steam pressure kept at 5 kg/cm2 and rotation speed kept at 50rpm. It has the cost-effectiveness of increasing stripper recycle rate by 1.55%, decreasing waste production rate by 19.46 ton/yr and saving the stripper purchase cost of NTD$1,322,600.
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Zheng, Jin-Zhong, and 鄭金忠. "The Effect of Process Parameters on the Evaporative Pattern Casting Process." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/83859192322886538376.
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碩士<br>逢甲大學<br>機械工程學所<br>98<br>The EPC process is a special casting process. The casting quality will be affected by the integrity of EPS pattern, selecting and analyzing of coating property, and the casting conditions etc. Therefore the optimal parameters in EPS pattern molding process, the composition design of coating and coating thickness, and the casting parameters (gating system design, vibration time, vacuum degree) need to be investigated entirely. They are very important factors on the surface quality and metallographic microstructure of casting.
Firstly, a step type metal mold is designed to produce EPS pattern. Then the effect on pattern surface quality of pattern molding conditions is investigated. Secondly, various self-designed coating is employed to investigate the effect of different coating composition on coating property including permeability, adhesive property, room temperature and high temperature crack property, etc. Finally, the best pattern and coating obtained from preceding steps are adopted to EPC processes, and the effect of casting parameters on surface quality of casting is investigated.
The experimental results indicate that in EPS pattern molding, the best process parameters are 110 °C molding temperature and 4'' 50" molding time which give the best surface quality and density of EPS pattern. The results of different composition of coating indicated that increasing the quantity of refractory B while decreasing the quantity of refractory A will cause the permeability declined slightly. The adhesive property will be increased and the crack resistance decreased gradually. Based on this research, the Type VI coating is the most suitable one. The permeability of Type VI coating is as high as 2.6 (expected value >0.5). In the adhesive property and crack resistance, Type VI are the runner-up in all tested coatings. Under the best EPS pattern and the best coating, the optimized casting conditions are described as follows: 1.vibration time is 20 seconds; 2.vacuum degree is 300 mmHg; 3.gating system is pressurized; 4.gating ratio is 1:0.9:0.8. The resulted casting A356 Aluminum alloy has great surface quality and metallographic microstructure.
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Wei-LunSun and 孫偉倫. "Casting Parameters to improve the White Spots of the Aluminum Billets." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3q22fh.
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Lin, Jia-He, and 林佳禾. "Optimization of Operating Parameters in the SAW/GC System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/7g2he2.
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碩士<br>中原大學<br>電子工程研究所<br>98<br>Abstract
Surface Acoustic Wave (SAW) Sensor has been quite widely used in gas detection sphere. Based on the surface wave transmission on the solid surface, the sensing stimulus can be determined through the SAW oscillator frequency drift to achieve the purpose of vapor sensing. The surface acoustic wave devices were studied in this paper for high sensitivity, low cost, and compact size in gas chromatography system. Quantitative study includes the optimization of the gas flow rate experiment, single gas under constant temperature experiments and mixed gas under constant temperature experiments. Finally, the scheme of modulated heating rate, with mixed gas heating procedure is used to study the gas chromatography/SAW system and optimal operating conditions.
The results show that four gas mixture the heating rate and temperature has been successfully distinguished by varying, including ether, toluene, butyl alcohol and cyclohexanone. "Heating rate" and "temperature-programmed" are two effective factors to speed the gas separation time. This work is important for the future development of a high speed and compact gas chromatography/SAW system.
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Lin, Yu-Chi, and 林于祺. "Investigation of Operating Parameters for Liquid Desiccant Dehumidification Process." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zr8c7n.
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碩士<br>國立臺灣大學<br>生物產業機電工程學研究所<br>106<br>Compared with solid desiccant dehumidification systems, liquid desiccant dehumidification systems are characterized by the low regeneration temperature, flexible regeneration time, and separable dehumidification and regeneration unit. Liquid desiccant dehumidification systems with thereafter cooling devices, which come with lower operating cost, lower-grade energy demand, and better performance in air quality and humidity control, could be an alternate for air conditioning. Therefore, there is great development potential in liquid desiccant dehumidification systems.
A large liquid desiccant dehumidifier has been constructed in this study. The parameters affecting the mass transfer of liquid desiccant have been discussed. The additional measurement system and the indicators for desiccant carry-over have been made and established. Vapor pressures of the mixed liquid desiccant aqueous solution reported in recent years have been measured in order to find the optimum mixing ratio for cost reduction. Finally, a small liquid desiccant dehumidifier has been constructed to test some more expensive liquid desiccant solutions.
In this study, with the CFD results in the large liquid desiccant dehumidifier, the additional measurement device with a height of 200 mm was designed and used in the system for the carry-over problem. The KDM421 demister was used on dehumidifier experiments because of the high average wind speed and the low degree of droplet residue. For the large and small dehumidifiers, various operating parameters such as air flow rate, inlet air temperature, and so on were explored. The performance of the large dehumidifier with lithium chloride solution was equivalent to a commercial dehumidifier with the dehumidifying capacity of 19.48 L/d and the energy factor of 2.50 L/kWh, falling on the second level of dehumidifier energy efficiency grade. The experimental results of calcium chloride, lithium chloride and potassium acetate solutions in the small dehumidifier show that the surface vapor pressure of the liquid desiccant solution is strongly related to the moisture removal rate in air.
Regarding the vapor pressure measurement of the mixed liquid desiccant solutions, the vapor pressure of the CaCl2+LiCl and LiCl+MgCl2 solutions both decreases with the increase of lithium chloride proportion. The vapor pressure of the LiBr+CaCl2 solutions increases with the increase of lithium bromide proportion. About the cost of mixed solutions, the cost of the CaCl2+LiCl solution increases with the increase of lithium chloride proportion. According to the cost and vapor pressure of the CaCl2+LiCl solution, the optimum ratio is 70% CaCl2+ 30% LiCl. Because the magnesium chloride used is more expensive than the lithium chloride, the cost of LiCl+MgCl2 solution decreases with the increase of lithium chloride proportion. The cost of the LiBr+CaCl2 solution increases with the increase of lithium bromide proportion.
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Lee, Kuo-Hua, and 李國華. "Optimization of Die Casting Parameters Using Grey Relational Analysis And Taguchi Method." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/4z49th.
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碩士<br>國立臺北科技大學<br>材料及資源工程系研究所<br>97<br>Die-casting magnesium alloys are often easily occurred defects as flow mark, insufficient filling, and warp etc. These defects are closely related with parameters of plunger velocity, injection temperature, and temperature of die etc. Due to liquid metal high-speed filling, it is not easy to predict the status of filling. So often easily design overflow and air vent at inappropriate location, making casting generated gas hole. Therefore, this study was the use of mold flow analysis software analysis tools as Procast to discuss filling the flow of liquid metal and the best location of the overflow and the air vent.
On improvement manufacturing process, industry is often considered optimization to the many of quality. Therefore, this study is aimed at AZ91D magnesium alloy die-casting parameters, selected the three control factors (plunger velocity, injection temperature, die temperature), each factor are the three levels, quality goals are set to the smallest solidification, pressure difference, the average temperature. By Taguchi method by S / N ratio analysis, a single target can be the optimization. Using of gray relational analysis method, simultaneously weighs the preferred plan and ideal solution and negative ideal solution characteristic, undergoes the Grey relational analysis, can find a group of best die-casting parameter A2 B1 C1, and its total gray value of the highest degree, so its really for the best combination of factor levels. The results indicated that gray relational analysis method for multi-objective analysis of die-casting parameters can indeed find the best die-casting parameters, and effectively reduce the casting defects and improve product quality.
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Yen, Wei-Feng, and 嚴偉峰. "Influence of Metallurgical Parameters and Process Parameters on the Fluidity of Al/SiCp Composites by Horizontal Squeeze Casting." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/54041104062578561710.
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碩士<br>大葉大學<br>機械工程研究所<br>90<br>The aim of this study was to investigate the influence of pressure process parameters, e.g., SiCp content (0~20wt%),metal mold temperature, squeeze pressure (8~13MPa/79~132kg/cm2) and casting thicknesses(representing cooling rate) on the fluidity of three types of Al-matrix SiCp composites (A356/SiCp,A413/SiCp
and A390/SiCp).
The experimental results indicate that the fluidity of three
types of Al-matrix SiCp composites tend to decrease with the increase of SiCp content and tend to increase with the increase of squeeze pressure. When the SiCp content added is more than 5wt% for the A356/SiCp composite, the fluidity will decrease. While, the SiCp content added is more than 10wt% for the A413/SiCp and A390/SiCp composite, the fluidity will decrease. In addition, compared A356/SiCp with A390/SiCp composites at different pressures, the fluidity is increased with pressure. However, the pressure affecting on fluidity for A356/SiCp or A390/SiCp composites have a threshold limit value, about 10.4MPa/106kg/cm2. Above threshold limit value, the fluidity is not clearly increased. In addition, the fluidity of composites is also increased with the increase of casting thickness for any composion of A356/SiCp、A413/SiCp and A390/SiCp composites.
Furthermore, the microstructure observation at different positions of strip casting were performed to correlate the solidification modes with the fluidity of three types of Al-matrix SiCp composites. Compared with the original aluminum matrix alloys, the solidification modes of A356/SiCp alloys does not change for any content of SiCp added. But A413/SiCp and A390/SiCp alloy is change for any content SiCp added. The structure at the strip casting of Al-matrix SiCp composites poured at high mold temperature or under high squeeze pressure reveals fine microstructure.
Keywords：Squeeze casting, Al-matrix SiCp composites, Fluidity,
Cooling rate
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Diltz, Robert. "Investigation on bioreactor operating parameters for optimum microbial hydrogen production." 2006. http://etd.lib.fsu.edu/theses/available/etd-11132006-145751.
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Thesis (M.S.)--Florida State University, 2006.<br>Advisor: Bruce R. Locke, Florida State University, College of Engineering, Dept. of Chemical and Biomedical Engineering. Title and description from dissertation home page (viewed Jan. 23, 2007). Document formatted into pages; contains viii, 52 pages. Includes bibliographical references.
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Lopes, Vanda Varela. "Electrokinetic Remediation of PPCPs in Soil: Effect of operating parameters." Master's thesis, 2018. http://hdl.handle.net/10362/40897.
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Reclaimed wastewater is an important source of water that complements the fragile and limited natural water sources, being widely used for irrigation of agricultural land, particularly in arid and semi-arid regions. Considerable levels of pharmaceuticals and personal care products (PPCPs), are found in effluents and in land fields irrigated with these “recycled waters”. Once in the soil, plants have the capacity to uptake, translocate and accumulate these compounds of emerging concern (CECs) in the edible parts of food crops. These can subsequently enter the food chain. This is of concern as some of these compounds act as endocrine disruptors.
The main objective of the present dissertation was to study and develop the electrokinetic process to promote CECs degradation using an agricultural soil as matrix. The developed technology was evaluated in terms of remediation efficiency and sustainability. For that, the soil was spiked with a 16 mg/kg solution containing five CECs. The selected compounds were: sulfamethoxazole (SMX), ibuprofen (IBU), triclosan (TCS), caffeine (CAF) and atenolol (ATN).
The feasibility of the electrokinetic (EK) process was evaluated by testing different operating modes, using graphite rods as electrodes. The main tested operating modes were: current intensity (CI); ON/OFF switch intervals (Sw); and reversed electro-polarization intervals (RP). For CI mode, 100, 50 and 10 mA were tested, for 24h ON in the case of CI-10 and 24h ON/OFF for CI-100 and CI-50. For Sw and RP systems (performed at 10 mA), periods of 6, 12 and 24h were tested. All experiments were carried out for a 7 day period, in a lab scale microcosms. Additionally, two complementary reference testes were done: initial control and control after 7 days, both without direct current (DC) electric field.
Experiment CI-50 showed high degrading percentages for some compounds (97 ± 8% of SMX and 61 ± 5% of IBU), but the electrodes were unstable and presented high signs of corrosion after 24h of 50 mA application. Experiment CI-10 presented the highest degrading percentage of TCS (56 ± 0%), but a significant soil pH gradient was observed (6.8-11.2). The results with periodic current application of 12h (Sw system) showed to be the most viable option for achieving the CECs degradation without submitting the soil to extreme physico-chemical changes. Removal efficiencies in experiment Sw-12h ranged between 36 and 72% (with RSD from 0 to 10%). Although. In this system, the electrolysis of water produced a subtle pH gradient. The slight physico-chemical changes promoted in the soil, may have enabled, to some extent, the solubilization and/or mobilization of contaminants under study. This may have enhanced the degradation of contaminants by two remediation mechanisms: (i) electrochemical degradation and (ii) bioremediation. The EK process shows to be a sustainable option for the remediation of CECs in clay soils, thus decreasing the environmental and humans associated risks.
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Tsai, Tsung-ming, and 蔡宗明. "The impacts of operating parameters on the PEMFC cogeneration system." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/71327980384563302333.
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碩士<br>國立臺南大學<br>綠色能源科技研究所碩士班<br>98<br>The purpose of this thesis is to design, fabrication, and testing a prototype of a PEM fuel cell co-generator with high-quality electricity and hot water. The first is to build the subsystems of the fuel cell co-generator, temperature control subsystem. Then, a microcontroller of the co-generator is developed and integration of the fuel cell co-generator is completed. Meanwhile, optimal control strategies for operation of the co-generator are proposed. Finally, parametric studies on the dynamic behaviors and efficiencies of the co-generator are presented, including office electricity use, The effects on operating temperature, secondary fluid, and tank capacity. Results showed that, For the effects on the operating temperature, the maximum efficiency of electricity generation, heat recovery efficiency, and combined heat and power efficiency are up to 32%, 43%, and 67%, For the effects on operation secondary fluid flow, the maximum efficiency of electricity generation, heat recovery efficiency, and combined heat and power efficiency are up to 31%, 59%, and 66%,For the effects on the operation tank capacity, the maximum efficiency of electricity generation, heat recovery efficiency, and combined heat and power efficiency are up to 31%, 49%, and 65% Respectively.
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Juan, Xhian-Yu, and 阮翔瑜. "Study on the Operating Parameters of Fine Gear Blanking Process." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/p7kg7d.
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碩士<br>國立臺北科技大學<br>製造科技研究所<br>96<br>Blanking process is one of the fastest and effective method for mass production of sheet metal parts. And fine blanking technology has the features for the manufacture of high precision small parts. However, the quality of product processed by fine blanking largely depends on the operating parameters used. Therefore, the purpose of this paper is to study the optimal operating parameters that can be used in the production of small gear shape sheet metal product. First, Finite Element method is used to simulate the whole blanking process and to informate like cutting force versus stroke relation, the stress-strain distribute of blanking parts are expand on review. Next, Taguchi quality design method is used to find the optimal parameters of experimental press used for fine blanking of gear shape sheet metal parts. The four control parameters used in this study are punch pressure, stroke of punch, counter punch pressure, and materials. The experimental result show that counter punch pressure has efficacious effect on the contouring accuracy of gear tooth property. And the quality of gear tooth made from brass seems to be better than those from carbon steels and aluminum alloy.