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Abstract In order to understand ball motions of new ultra-precision ball grinding machine, this study presents an mechanical model using a transparent acrylic container to simulate ball motions. The effects of float material, load, and process condition on the ball grinding characteristics at low shaft speed. The ball motions can be observed by the CCD camera to calculate the ball¡¦s circulation speed , the ball¡¦s spin angular speed and the ball¡¦s spin angle . Furthermore, the kinematic equations of ball motion is derived with different rolling sliding condition. The theoretical values of , , and are compared with the experimental values under pure rolling condition. Results show that the theoretical values are in good agreement with the ball¡¦s spin angular speed, but with larger error for and .This error is still in range of engineer error. Hence, at low shaft speed, contacts between balls and container, or shaft or float are close to the pure rolling conditions. Because the higher friction force between ceramic balls and alumina float, the ball¡¦s circulation speed with alumina float than that with acrylic float since fluid thrusts balls at low shaft speed, the ball¡¦s circulation speed in working fluid than that without working fluid. Since mass of float is light, it can be drive easily. Hence, with increasing the load which also increases the float mass, the float angular speed is decreased and the ball¡¦s circulation speed is also decreased.

With the increasing complexity in construction projects, monitoring project schedule and managing projects effectively is becoming increasingly important. Most projects being deadline oriented, timely completion becomes a must. Like every industry, the construction industry too lays a lot of emphasis on timely completion which makes it necessary to monitor the project schedule very closely. A schedule overrun is never predicted at the start of the project but during the course of the project, even the slightest change can result in delays. As per the current scheduling practices, float is considered free. It is an expiring resource and hence the party to the use the float first owns the float. The concept endorsed by the court for analyzing delay claims is the proximate cause concept. As per this concept, the party which is the immediate cause to a particular delay is held responsible for that delay irrespective of what has happened before in the project. Due the ambiguous nature of its interpretation, the present concept on float management has now become one the primary reasons for disputes amongst the participating parties. Parties in contract are always trying to appropriate float to suit their interests. This is why total float management has gained this level of importance in today's industry. To handle this issue of total float management more efficiently, Dr. Prateapusanond (2003) proposes a new concept of total float management as an effort towards a more fair and equitable system. This concept respects the dynamic nature of construction projects and recognizes float to be an asset for both parties. The new concept proposes to allocate float in the ratio 50:50 between the parties at the start of the project. This pre-allocated float owned by each party is called the Allowable Total Float (ATF). The implementation of this concept ensures that the parties are now aware that consumption of float in a way that it affects critical activities will expose them potential damages. This concept is an effort towards a more fair and equitable system for total float management. It appears impressive on paper but its practicality and applicability remains a major concern. This research is aimed at testing the practicality of the proposed concept of pre-allocation of total float. It introduces bookkeeping procedures that will facilitate the application of the concept of Pre-allocation of total float. These procedures have been developed and tested on certain case studies to make sure that they are robust. Once their ability to handle scheduling issues is determined, the bookkeeping procedure along with the concept of pre-allocation of total float is applied to a real construction project. This research presents an in depth analysis of the nature of the proposed concept of pre-allocation of total float, the scheduling issues which this concept does not address to, and certain assumptions which could be used in conjunction with the present concept to make it robust in nature. / Master of Science

­^¤åºK­n A time-independent finite-difference numerical scheme is developed to study the dynamic response of a submerged and a floating breakwater under the wave loading of a fully numerical force. The coupled surge, heave and pitch motion of a floating breakwater and the wave-structure interaction are included in the model. The numerical results are validated uses several bench mark studies and results available elsemlse. The wave reducing effect of a submerged and a floating breakwaters were analysis and discusse.

A systematic study of the properties of ion-exchanged float glass has been carried out by a.c. impedance spectroscopy. The measurement of electrical parameters allows the ionic mobility within the surface region to be investigated separately from the bulk glass. The correlation of a.c. impedance measurements with electron probe micro analysis, infrared reflectance spectroscopy, differential scanning calorimetry and dynamic mechanical thermal analysis has lent some new insights into anomalous behaviour of ionic transport under these circumstances. A highly resistive layer is found to exist as a result of the ion-exchange process in float glass. This is not attributable to compressive stress alone nor does the mixed alkali effect (MAE) operate within this diffusion zone. Glasses of the same composition prepared by homogeneous mixed-melting, however, indicate a strong mixed alkali effect. Infrared reflectance spectroscopic measurements clearly illustrate a more uniform distribution of non-bridging oxygen ions (and therefore some structural relaxation) as a result of ion-exchange. This also holds true for the comparison of ion-exchanged glass and mixed-melted glass. This result clearly shows that a different structure is generated depending on whether alkali cations are mixed homogeneously or via the ion-exchange process. It is proposed that some type of foreign ion repulsion effect (FIRE) operates when the larger cation is substituted into the glass below T_g. The repulsion of such foreign cations, and their search to find their own new sites causes their immobilisation (and a slow ion-exchange process) via the break up of conduction pathways, and thus the conductivity continues to decrease without any recovery, as more K⁺ ions are introduced. In contrast, only a weak mixed alkali effect is apparent in melt-grown lithium-alumino-silicate compositions and no high resistance (or cation immobilisation effect) is found in the ion-exchanged alumino-silicate system.

Master of Veterinary Biomedical Science / Department of Diagnostic Medicine/Pathobiology / Michael W. Dryden / Patricia A. Payne / Giardiasis is a common intestinal protozal parasitic infection of the pet dog and cat population. Veterinarians often have difficulty correctly diagnosing this parasite. Studies were conducted to compare the zinc sulfate double centrifuge fecal flotation to the SNAP (registered trademark) Giardia fecal ELISA test manufactured by IDEXX laboratories Inc. in purpose bred beagles and shelter and commercial kennel dogs. In these evaluations the zinc sulfate double centrifuge fecal flotation and fecal ELISA test performed similarly. Both tests performed better in the shelter and commercial kennel dog population than the chronically infected purpose bred beagles. There was an increase in number of positive animals identified when 3 consecutive daily samples were evaluated as compared to any one individual day for either test method. Post treatment evaluation of the diagnostic tests was performed in 23 laboratory beagles. Each beagle was treated for 3 consecutive days with Drontal plus and then bathed on the last day of treatment and fecal samples were collected from the treated dogs every other day starting one day post treatment for 21 days. It was found that all beagles were negative on zinc sulfate double centrifugation fecal flotation, fecal ELISA and IFA within 24 hours of treatment and nineteen (82.6%) of the beagles did not re-shed cysts during the 21 day post-treatment evaluation period. Four beagles returned to shedding cysts (Flotation or IFA positive) between days 17 and 21. These findings suggest that a positive test within a week of treatment is likely the result of inappropriate treatment. After the prepatent period, positive results may occur due to a return to shedding, reinfection or inappropriate treatment. Chronically infected laboratory beagles may not be a good model for acute Giardia infections as these dogs are rarely clinically ill and detection is more difficult.

A pré-concentração consiste no descarte prévio de uma fração da ganga liberada, ou parcialmente liberada, com pouco ou nenhum conteúdo de interesse, antes da alimentação da usina. Tal prática pode levar a uma série de benefícios nas operações subsequentes, como redução do consumo de energia por tonelada de metal produzido, nos casos em que o material rejeitado apresentar WI (work Index) elevado; diminuição do desgaste abrasivo, quando a ganga rejeitada exibir AI (Abrasion Index) alto; além de aumento de recuperação na flotação e eliminação de flutuações no teor da alimentação. Neste sentido, a pré-concentração diminui custos operacionais e aumenta a rentabilidade da usina. Este trabalho teve por objetivo avaliar a aplicabilidade de pré-concentração para o minério de zinco silicatado de Vazante/MG. Em uma primeira etapa foram executados estudos de liberação da ganga no produto de britagem, explorando as propriedades luminescentes do minério. Para isto, imagens de contraste de cores luminescentes foram obtidas e tratadas no Image J. Obteve-se um valor de liberação da ganga da ordem de 85%. Em um segundo momento, foi investigado o desempenho de técnicas de separação densitária e seleção por sensores (ou ore sorting) como alternativas para a pré-concentração do minério de zinco e remoção de ganga carbonática, para isto, foram utilizados ensaios de afunda/flutua em líquidos densos, que simularam uma operação em meio denso, estratificação em jigue e ensaios em sorter com sensor de transmissão de Raios-X de energia dupla (DE- XRT). O melhor resultado foi obtido através do ensaio de afunda/flutua com densidade de separação de 2,95 g/cm³, no qual foi alcançado um descarte de 30% da massa de alimentação como produto flutuado, numa fração -25 +1,18 mm, removendo 60% dos carbonatos (CaO e MgO) e perdendo apenas 2% de zinco. Os ensaios do sorter também apresentaram resultados positivos, com aproximadamente 93% de recuperação metalúrgica de zinco e um descarte de aproximadamente 30% da massa, mas com uma perda de zinco considerável (aproximadamente 5% em teor). Para a jigagem, os resultados indicaram teor de zinco muito elevado no rejeito (aproximadamente 6%). Entretanto, uma jigagem adicional, realizada com uma segunda amostra numa granulometria menor (-12,7 +1,18 mm), proporcionou menores níveis de zinco perdido para o rejeito, apenas 3,6% em teor. Os impactos da pré-concentração na moagem e flotação também foram avaliados. Para isto foram executados ensaios de work index (WI), abrasion index (AI) e flotação com material tal qual (sem passar por pré-concentração) e com o material pré-concentrado de forma a se ter um comparativo. Como não houve variação de WI e nem de AI entre as amostras tal qual e pré-concentrada, a pré-concentração previamente à moagem, não irá impactar no consumo energético e tampouco no desgaste abrasivo, isto se for adotada a estratégia de manter a mesma vazão mássica de alimentação do circuito de moagem para ambas as alternativas. Em linhas gerais, a flotação após a pré-concentração aumentou a produção de concentrado de zinco com uma qualidade superior em termos de recuperação deste metal. Outro impacto positivo observado foi a redução da quantidade de rejeito fino de flotação e, consequentemente, o volume a ser estocado em barragem. / Preconcentration consists of the prior disposal of a fraction of the liberated or partially liberated gangue with low or no content of interest material before plant feed. Such practice can lead to a number of benefits in subsequent operations, such as reducing energy consumption per ton of metal produced, in cases where the rejected material presents a high WI (work index); decreased abrasive wear when the rejected presents high Abrasion Index (AI); increased recovery in flotation and elimination of fluctuations in feed content. Therefore, preconcentration reduces operating costs and increases the profitability of the plant. This work had the objective of evaluating the preconcentration applicability for a silicate zinc ore from Vazante/MG. In the first stage, grind release tests were performed on the crushing product, exploring the luminescent properties of the ore. For this, luminescent color contrast images were obtained and treated in Image J. A gangue release value of the order of 85% was obtained. Second, the performance of densification separation and sensor sorting (or ore sorting) techniques were investigated as alternatives for preconcentration of zinc ore and removal of carbonate gangue, for this, sink/float tests in dense liquids were used to simulate a dense medium operation, as well jig stratification and sorter tests with dual energy X-ray transmission sensor (DE-XRT). The best result was obtained by the sink/float test with separation density of 2.95 g / cm³, in which a 30% discard of the feed mass as a flotation product was achieved, in a fraction -25 +1.18 mm, removing 60% of the carbonates (CaO and MgO) and losing only 2% of zinc. The sorter tests also showed positive results, with approximately 93% metallurgical recovery and a discard of approximately 30% of the mass, but with a considerable loss of zinc. For jigging, the results indicated very high zinc content in the tailings (approximately 6%). However, additional jigging, performed with a second sample at a smaller particle size (-12.7 +1.18 mm), resulted in lower levels of zinc lost to the tailings, only 3.6% in content. The impacts of preconcentration on milling and flotation were also evaluated. For this, work index (WI), abrasion index (AI) and flotation tests were carried out with the material without preconcentration and with the preconcentrated material in order to compare. As there was no variation of WI and AI between the samples, the preconcentration prior to milling will not impact on energy consumption or on abrasive wear, if the strategy of maintaining the same mass flow rate of the milling circuit for both alternatives is adopted. In general terms, flotation followed by a preconcentration strategy can increase zinc production without requiring expansion of the plant\'s capacity. Another positive impact was the reduction of the amount of fine flotation tailings.

Glass is a common material in each person’s life, e.g. drinking vessels, windows, displays, insulation and optical fibres. By modifying the glass surface it is possible to change the performance of the entire glass object, generally known as Surface Engineering. Ion exchange is a convenient technique to modify the glass surface composition and its properties, e.g. optical, mechanical, electrical and chemical properties, without ruining the surface finish of the glass.   This thesis reports the findings of two different research tasks; characterisation of the single-side ion exchange process and the novel properties induced. The characterisation of the ion exchange process was mainly performed by utilising a novel analytical equipment: the Surface Ablation Cell (SAC), allowing continuous removal of the flat glass surface by controlled isotropic dissolution. SAC-AAS has provided concentration vs. depth profiles of float glass ion exchanged with K+, Cu+, Rb+ and Cs+. In addition, SEM-EDX has provided concentration vs. depth profiles of Ag+ ion exchanged samples and validation of a copper concentration vs. depth profile. From the concentration vs. depth profiles, the effective diffusion coefficients and activation energies of the ion exchange processes have been calculated. Depending on the treatment time and treatment temperature, penetration depths in the range of 5-10 μm (Rb+, Cs+), 20-30 μm (K+, Cu+) and 80-100 μm (Ag+) can be readily obtained. The effective diffusion coefficients followed the order Ag+>K+>Cu+>Rb+>Cs+. This is in accordance with the ionic radii for the alkali ions (K+<Rb+<Cs+) but reverse for the noble metal ions (Cu+<Ag+).   The glass properties modified by single-side ion exchange have mainly been characterised by UV-VIS spectroscopy and flexural strength measurements. Cu+ and Ag+ ion exchange give rise to surface colouration, Cu+ copper-ruby and Ag+ yellow/amber. The surface-ruby colouration was found to depend on the residual tin ions in the tin-side of the float glass. The flexural strength was studied using the coaxial double ring-test method which also was suitable for holed specimens. The flexural strength of K+ ion exchanged float glass samples was found to substantially increase compared to untreated.

In the present study we use Argo float data, in-situ shipboard ADCP data,IFREMER wind stress curl data, QuikSCAT wind data and AVISO sea level anomaly data from 2006 to 2010 to investigate hydrographical characteristics and surface and deep currents in the seas surrounding Taiwan. The studied areas consist of the followings: the cyclonic eddy off the northeastern Taiwan coast, flow structure of the Luzon Strait, anticyclonic eddies off the southwestern Taiwan coast and east of Kuroshio. Our results found that some Argo floats drifting northward with the Kuroshio were occasionally intruded to the continental shelf off the northeastern Taiwan at 25¢XN-26¢XN,122¢XE-123¢XE. Statistics indicate that this phenomenon occurs most frequently in winter, and float profiling data reveal a marked upwelling above 150m depth. Temperature drops within this area can reach 5.1¢J and 8¢J, respectively at 50m and 100m depths. A deep southward current with a maximum speed of 30 cms can be found to exist between northeastern Taiwan and Kuroshio. On the other hand, Surface flows have strong seasonal variations in the Luzon strait, i.e., toward the southeastern side of Taiwan in the summer and intrude into the South China Sea (SCS) in the fall and winter. Deep currents in the Luzon Strait, however, flow mostly into the SCS regardless of seasonality. Maximum speed of deep current can reach 6 cms . Mixed-layer depth in the northern SCS is approximately 50m in the spring and summer, and about 110m depth in winter. The third part of this thesis concerns with the anticyclonic circulation off the southwestern Taiwan coast. Float observations show that this circulation exists almost all year round in 2009. Surface currents have a maximum speed in early May, reaching 104 cms , and the wind stress curl attains a maximum negative value. It is conjectured that this anticyclonic eddy is generated primarily due to the restriction of local coast and topography, and the wind stress curl is the secondary mechanism. Surface current derived from Shipboard ADCP is also consistent with the float results. The diameter of this eddy is about 110 km. T-S characteristics of Kuroshio can be observed at 150-210m depth, indicating a close link between this eddy and the Kuroshio. Finally, anticyclonic warm eddies east of Kuroshio are also investigated from the float data. It is found that the eddy flow structure in this region is more obvious in depths than in surface. Temperature distribution below the depth of 200 m also confirms the warm core structure. At an event during which when one float incidentally travelling through a cold eddy and an adjacent warm eddy, the temperature difference can reach 4.5 ¢J at 160m depth. The warm eddies are found to be more stable and more frequently observed than the cold eddies in this region.