Drying process needs lots of energy and usually prone to high equipment and operational cost. Research tasks have focused on improving the drying performance and reducing the energy consumption rate. Among a number of industries, textile manufacturing needs the process intensively. It is surprising that little research has concerned principle enhancement and drying process design. In the support by Fong’s National Engineering Company Limited, a series of research that targeting to the inadequacy of technology development for machinery and process design have been conducted. The redevelopment of machinery design has based upon a heat setting machine –ECO dryer. The machine was used as a working platform to supply all necessary testing information before and after the enhancement. The ductwork and air distribution system design have been revised to improve the unevenness drying problems appeared in the heat setting of fabrics. Two main research scopes have been performed that included the development of a new duct sizing approach –Uniform Jet Velocity (UJV) and redesigning the air chambers. The proposed UJV approach is a new air duct design model developed from fluid dynamics principles. The air jet speed along each nozzle is maintained at a constant rate to provide a uniform jet impingement effect. A duct size algorithm was proposed to adjust the cross sectional area ratio between the main and branch streams for the target of producing a constant impingement velocity across the entire air duct. In the enhancement of the air distribution system design, Computational Fluid Dynamics (CFD) analytical approaches were used to model air flow patterns before and after the redesign of air chambers. The CFD analysis results told that a linear air distribution system with four sub-chamber design could produce the best air distribution pattern on the ECO dryer. The request of an accurate drying cycle time predication is also large in textile industry. It is because the problems of under-and over-drying usually happen in the jet impingement process. The second essential objective in the research is to develop systematical approaches for a good qualifying of a drying cycle. Four analytical models have been studied that included First order kinetics, Diffusion, model based on solutions of diffusion equation and Wet surface. An equation for each of the models was developed to describe the characteristics of a porous type fabric drying process. In the study, the required modeling parameters were empirically determined, and the accuracy among the models has been compared. Findings from the research have proved that the model based on solutions of diffusion equation can be the best strategy in presenting a drying cycle under different machine settings. The investigation has not ceased after the completion of the hot air jet impingement research. The study objectives have moved onto an alternative drying technology using steam as the drying medium. Due to many problems reported in the drying of yarn packages using electro-magnetic waves, moist heat drying technology is urgently needed. At the final part of the research, two CFD simulation models namely constant viscous resistance and increasing viscous resistance were studied. A preliminary result generated from ANSYS CFD analysis results was obtained that has opened up a new study area for further elaboration of a new drying technology, and hopefully can be practically applied to textile industry in the near future. / published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Vita. / Digitized by Kansas Correctional Industries

The objective of this research was to design and evaluate an instrumental method for electroanalysis in highly resistive media. A coulostatic detector for high performance liquid chromatography was designed and constructed. Equations were developed to describe the detector's performance under regenerative and nonregenerative experimental conditions. With mobile phases of high resistance, the detector was found to respond to both electroactive and ionic electroinactive species with the magnitude of the observed signal depending on the recent history of the electrode. Thus, the elimination of iR drop by the coulostatic method does not provide a straightforward method for electroanalysis in highly resistive media. At low electrolyte concentrations, double-layer effects become prominent. A method was devised to quantitate the static double-layer effect at solid electrodes.

No description available.

M.S.

M.S.

Steam distillation is the most widely accepted process for the large scale production of volatile essential oils from herbaceous material and is also regarded as the standard practice throughout the flavour and fragrance industry. A mobile essential oil distillation unit for the extraction of oils from herbaceous materials would be extremely valuable to the essential oil industry in South Africa. Using a mobile platform, the extraction technology could be taken to rural areas where essential oil crops are grown in order to extract and then analyse the oils produced. Existing systems in South Africa are static distillation units which are usually owned by commercial growers that are generally positioned large distances away from the rural areas. The objective of this project was to design, construct and test a prototype mobile distillation unit for the extraction of essential oils from herbaceous materials. The unit was to have a charge vessel capacity of approximately 250 kg of plant material and should be able to perform in-field distillations in areas where electricity is not available. A literature review on all the essential oil extraction methods, the theory behind steam distillation and oil isolation and the effect that each of the distillation components have on the distillation process was performed. A small test distillation unit was set up in a laboratory in order to investigate the effects of varying steam flow . rates on the distillation time, oil yield and oil quality. A double charge vessel unit was designed, constructed and mounted onto a frame which in turn was fixed onto a trailer to be hauled by a light delivery vehicle (LDV). The steam generator with all its ancillary equipment was fixed onto a separate trailer. The unit could thus be easily transported and in-field distillations on various crops could be conducted. Field distillations were conducted with two crop types, namely rose geranium and lemon grass. Satisfactory results were obtained as the oil yields were within the expected oil yield range. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2005.

In modern life, human have become dependent on portable electronics, such as cell phones, MP3 and handheld computers, most of which are powered by batteries. Although the performance of batteries is being continuously improved, the limited energy storage and service life constrain the lasting use of these mobile electronics. Therefore it is desirable to find alternative or supplementary methods to solve this problem from its root cause. It is known that human body contains rich chemical energy, part of which is converted to mechanical energy up to 200W when in motion, so it is ideal to harvest a small fraction of the human kinetic energy to power mobile electronic devices. / In this thesis, first, the previous work done by other researchers on energy harvesting from human motion, especially from unintentional human motion, such as arm swing and leg moving, is reviewed. Then the fundamental principles to mechanically harvest motion energy are discussed, including the mechanical oscillating mechanisms and electromagnetic transduction. Derived from the general harvesting model, four different devices are designed and analyzed. / Shoe is important for human, one of which functions is to serve as shock-absorber to protect foot from the large impact force. As the foot strikes the ground, the shoe is subject to not only large force but also large displacement in the heel. The third new device is designed to insert in the shoe heel to harvest the kinetic energy from foot strike, and at the same time to function as a shock absorber for foot. Considering the stability and efficiency, a spring-slider-crank mechanism is used in this harvester to covert the up-down foot strike motion into unidirectional rotation to drive an AC generator. The spring and slider compose an oscillating system to absorb the foot strike motion, and crank and slider make up the conversion mechanism to transfer the bi-directional translation into unidirectional rotation. A set of gear is used to speed up the rotation. The kinematical performance of the harvester is also analyzed. / The first one is the automatic winding mechanism of mechanical movement. It consists of an oscillating weight, a ratchet mechanism, a gear set and a mainspring. The mechanism can be modeled as a double pendulum when worn on a user's wrist. Its kinematical performance is analyzed with experimental validation. / This thesis discusses the feasibility of mechanical power generators driven by human motion, with the focus on their architecture design and performance analysis. The main objective is to develop effective power generators for harvesting the energy from human motion, and use it to power portable electronic devices. / To directly convert the human arm motion to electricity, the second novel energy harvester is designed, analyzed and simulated. It mainly consists of an eccentric rotor made of permanent magnet, and a set of coils as a stator. The eccentric rotor, as a simple pendulum, acts as the kinetic energy harvester which absorbs the motion from human body in motion. With the permanent magnets on the rotor, the moving rotor produces a changing magnetic field, from which the stator induces electricity. In this design, a torsion spring is also added onto the rotor so that the harvester works even when the motion is on horizontal plane. / When foot strikes the ground, a large acceleration is produced. The fourth new energy harvester uses dual-oscillating mode. It contains two oscillating mechanisms: one is spring-mass oscillator to absorb the vibration from footstep motion, and the other is cantilever beam using the tip mass to amplify the vibration. Analysis shows that the dual-oscillating mechanism can be more effectively harvest the foot step motion. The energy conversion sub-mechanism is based on the electromagnetic induction, where the coils fixed at the tip end of the cantilever beam serves as the slider, and the fixed permanent magnets and yoke produce the changing magnetic field. Mathematical analysis and simulation are included. / Xie, Longhan. / Adviser: Ruxu Du. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 124-128). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

No description available.

The thin-layer flow-cell incorporated an array of 32 gold strip electrodes in a serial configuration opposite a platinum counter electrode. The cell body was made of Macor glass ceramic. A photolithographic procedure for etching the Macor and a simple method of applying a gold ink was devised. Resistive feedback current-to-voltage converters independently controlled the potential difference between the electrodes of the array and the common counter electrode. A microcomputer and a customized high speed data acquisition interface recorded the current response of each electrode. An expression for the faradaic response of a single electrode within a rectangular flow channel was modified to predict the behavior of the multi-electrode flow-cell. The quinone/hydroquinone redox system was used to evaluate the performance of the detector. Summing the signals from the array when all electrodes were held at the same potential improved the signal-to-noise ratio. Hydrodynamic curves were reconstructed from the currents measured at each electrode when a ramp potential profile was applied to the array.