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Made available in DSpace on 2014-10-09T12:49:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:16Z (GMT). No. of bitstreams: 0 / Quando um país se torna auto-suficiente em uma parte do ciclo nuclear, quanto à produção de combustível que será usado em suas centrais nucleares para a geração de energia, precisa voltar sua atenção para a melhor forma de armazenar este combustível após a sua utilização. A armazenagem do combustível nuclear queimado é uma prática necessária e utilizada nos dias atuais em todo o mundo como temporária, tanto por países que não têm definido o plano de destinação final, isto é, o repositório definitivo, como também por aqueles que já o possuem. Existem dois aspectos principais que envolvem os combustíveis queimados: um referente à armazenagem do combustível nuclear queimado destinado ao reprocessamento e o outro ao que será enviado para deposição final quando o sítio de deposição definitiva estiver definido, corretamente localizado, adequadamente caracterizado quanto aos diversos aspectos técnicos, e licenciado. Este último aspecto pode envolver décadas de estudos por causa das definições técnicas e normativas em um dado país. No Brasil, o interesse está voltado para a armazenagem dos combustíveis queimados que não serão reprocessados. Este trabalho analisa os tipos possíveis de armazenagem, o panorama internacional e a possível proposta para a futura construção de um sítio de armazenagem temporária no país. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP

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Storage ring light sources are in use around the world operating as high brightness photon sources from the infrared to the X-ray photon regimes. Whilst modern light source designs achieve horizontal emittances in the few-nm range, they are only diffraction limited in the vertical plane with emittances as low as 10~pm-rad. To achieve fully diffraction limited light sources in the X-ray regime requires a fundamental change in the design of such machines. Many such designs have been proposed based on the multi-bend achromat (MBA) lattice, which have been shown to achieve the required emittance reduction. However MBA lattices typically have a reduced dynamic acceptance, and consequently shorter beam lifetimes. Whilst this can be ameliorated somewhat through the use of top-up injection schemes, many issues still remain. In this thesis we explore one possible alternative to the multi-bend achromat (MBA) paradigm: the stacked storage ring. We propose a storage ring consisting of two synchrotrons joined via a static magnetic vertical transfer line. One of the rings has a reduced emittance through the use of high field damping wigglers, whilst the other is used for standard user experiments. The cumulative emittance of the combined ring structure is a function of the emittances of the two rings. The stacked ring approach allows for a reduction in the beam emittance without a consequent increase in the machine footprint, as in the case of the MBA lattice. Additionally, we may use the more relaxed lattice structures popular in currently operating 3rd generation light sources to maintain a reasonable dynamic acceptance even with the reduced emittance. We apply the stacked storage ring concept to the design of a low emittance 700~MeV compact light source for low energy vacuum ultraviolet photon output. The desirability of such a low energy photon source for UK science has previously been explored in depth. We examine the design of such a light source based around a strong damping stacked storage ring in the presence of Touschek and Intra-Beam scattering whilst analysing the effects on the dynamic properties of the lattice. We also apply the stacked ring concept to two lattices designed to operate in the high energy X-ray region of the photon spectrum and investigate the potential advantages in this regime, including as an adjunct to further improve proposed MBA concepts.

Minneola tangelos were obtained from different production areas in two seasons (1996: Western Cape and Swaziland, 1997: Western and Eastern Cape), and stored at two different temperature regimes simulating the shipping and storage treatments of fruits for overseas markets to determine if storage regimes have an influence on quality parameters. Samples were taken every two weeks and quality parameters such as fruit shape index, mean rind thickness, % juice, %TSS, and % acid were determined. An experiment to determine weight loss during storage time was done at the same time. Main significant differences across all the parameters were observed between fruits from the different production areas, while fruit shape, % juice, and occurrence of rind breakdown did not differ significantly. In 1996, the weight loss developed in storage only showed a significant difference after 8 weeks in storage. In 1997, there was no clear pattern, but the interaction between producers and storage temperatures differed significantly. Focusing on the producer from the Western Cape, there was a significant difference between storage temperatures, confirming that citrus fruits stored at a higher temperature (11°C) will loose moisture faster than those stored at a lower temperature (4.5°C). Even with the higher moisture loss, there were no differences between the fruit stored at the different temperatures, apart from the difference between the producers indicating that changes in quality of 'Minneola' fruit are mainly determined by the producers and apparently to a lesser extent by storage temperatures of 4.5°C and 11°C. With the high rate of over-maturity developing in storage, it is possible that the fruit might have been stored too long. Therefore, the marketing period for soft citrus types is apparently too long and problems with physiological ageing can be abundant at this storage length. / Dissertation (MSc (Agric) Horticultural Science)--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

Class of 2013 Abstract / Specific Aims: To determine if temperature and direct sunlight influence the rate of evaporation of normal saline in 100mL IV bags. Methods: Four study groups were created; refrigeration, dark shelf, shelf near window, and EMT box simulation. 80 bags (50 ml bags of normal saline) placed in different areas of temperature change and sun exposure. 20 of the bags stored in a drawer in a refrigerator. 20 stored on a shelf in a dark temperature controlled room. 20 stored next to a window in direct sunlight, and 20 stored outside where temperature and sun exposure will be highest in an EMT simulated box. Weights were recorded (in gms) weekly for 8 weeks using an analytical balance. Each saline bag was weighed individually and recorded at the time of measurement. Main Results: Rates of volume loss were lower in the normal saline IV bags stored in a refrigerated environment compared to the other two groups stored at room temperature and the one group stored in outside conditions (p<0.001). IV bags stored at room temperature exposed to light had the second lowest rate of loss compared to the other two groups (p<0.001 compared to outside conditions and p=0.003 compared to closed drawer). Bags stored at room temperature in a closed door had the third lowest rate of loss (p<0.001). Conclusion: Rate of fluid loss from IV normal saline bags appears to be temperature sensitive and storage of these bags may have an impact on shelf life of the product.

Parallax is a distributed storage system that uses virtualization to provide storage facilities specifically for virtual environments. The system employs a novel archi-tecture in which storage features that have traditionally been implemented directly on high-end storage arrays and switches are relocated into a federation of storage VMs, sharing the same physical hosts as the VMs that they serve. This architecture retains the single administrative domain and OS agnosticism achieved by array- and switch-based approaches, while lowering the bar on hardware requirements and facilitating the development of new features. Parallax offers a comprehensive set of storage features including frequent, low-overhead snapshot of virtual disks, the “gold-mastering” of template images, and the ability to use local disks as a persistent cache to dampen burst demand on networked storage. / Science, Faculty of / Computer Science, Department of / Graduate

No description available.

High-moisture barley, preserved either anaerobically, chemically or by drying, was evaluated in a series of digestibility and nitrogen utilization trials with monogastrics and ruminants. In the first of 3 phases, high-moisture barley HMB (17% moisture) from the Peace River region was preserved in experimental silos by: (1) airtight storage, (2) alkali - 3.2 g NaOH/kg HMB (air dry basis) in a 32% w/w solution, (3) acid - 1% mixture of 60:40 acetic-propionic acids and (4) drying - 8 tonnes per hour at 82°C. After 9 months of storage, these treatments were evaluated in a digestibility trial with pigs and a nitrogen balance trial with rats. In the pigs there was no treatment effect on dry matter digestibility, but neutral detergent fibre digestibility was reduced (P < 0.001) in the dried barley. True nitrogen digestibility, with both pigs and rats, was significantly (P < 0.001) reduced by alkali treatment. In the rat trial, alkali-treated barley depressed net protein utilization (NPU) by over 20%. Differences between the non-alkali treatments were small. Digestibility studies with sheep were not carried out on these treatments due to poor palatability results. In the second phase, barley from Lacombe was harvested at 33 and 12% moisture. The HMB (33% moisture) was either stored airtight or artificially dried (ADB) to 88% DM and the field-dried barley (FDB) (12% moisture) was either stored aerobically or reconstituted (RB) to 70% DM and stored airtight. These treatments were evaluated in a nitrogen balance trial with rats and a digestibility, nitrogen-retention trial with sheep. In the rat trial, true nitrogen digestibility was highest (P < 0.001) for HMB while biological valve was higher (P < 0.001) for both of the dry treatments. NPL) tended to be the same for all treatments. In the sheep trial, dry matter digestibility of RB was improved above ADB, but organic matter digestibility of both HMB and RB were greater than that of ADB (P < 0.01). Acid detergent fibre digestibility of HMB was highest (P < 0.001) followed by FDB and RB and then ADB. There was no treatment effect for either nitrogen digestibility or nitrogen retention. Straw from both HMB and FDB was also evaluated in sheep. Apparent dry matter, organic matter and nitrogen digestibility were all significantly (P < 0.001) greater for straw from HMB. The final phase of the study was conducted with barley of an unknown origin. Dry barley was reconstituted to 30% moisture (RB) and portions were treated with 3% NaOH (NaOH-RB) or 1% and 3% anhydrous ammonia (NH3-RB) on a w/w air dry basis. These treatments were again evaluated in a nitrogen balance trial with rats and a digestibility, nitrogen-retention trial with sheep. In the rat trial, true nitrogen digestibility for NaOH-RB was approximately 20% lower than the other treatments. Biological value and NPU were also depressed below all other treatments by NaOH-RB (P < 0.001). NPU for both 1 and 3% NH₃-RB were lower (P < 0.001) than RB after most of the NH₃ was allowed to evaporate for several days. However, there appeared to be no residual effect on protein utilization after the NH₃ was removed completely from the treated barley, as NPU for both 1 and 3% NH₃-RB were not different from RB. Dry matter digestibility was improved by all alkali-treatments (P < 0.001). In the sheep trial, both apparent dry matter digestibility and organic matter digestibility were significantly (P < 0.01) better for only the 3% NH₃-RB as compared to the other treatments. Acid detergent fibre digestibility was lower for 1 and 3% NH₃-RB than RB or NaOH-RB, between which treatments there were no significant differences. NaOH treatment reduced nitrogen digestibility by approximately 20 percentage units, but nitrogen-retention was unchanged between treatments with sheep. / Land and Food Systems, Faculty of / Graduate

M.Ing. / Ice storage systems are used to store thermal energy in the form of ice build-up inside storage tanks. During off peak hours, the chiller is used to charge up the storage tank until it is full. During on peak hours, the storage is discharged to meet a certain fraction of the building cooling load. The control strategy employed determines the extent to which the storage compensates the chiller and visa versa. Given the way in which electricity rates are structured, ice storage systems become an effective energy management strategy. The objective of the study is to compare energy savings derived by using conventional control strategies versus optimal control. Conventional control strategies can be classified as chiller priority control, constant proportion control and storage priority control. In chiller priority control, the chiller meets the cooling load subject to a pre-set limit not being exceeded. Should the limit be exceeded, the remaining cooling load (at each time horizon) is compensated for by the storage. In constant proportion control, both the storage and chiller meets a constant proportion of the cooling load. Storage priority control attempts to discharge as much of the storage as possible, such that at the end of the planning horizon, the ice build up in the storage tank is just depleted. Optimal control employs dynamic programming to ensure that the integrated cost of energy, during the entire planning horizon, is minimal. A steady state ice storage plant model for analysing the performance of the control strategies is presented. The model computes the inlet and outlet temperatures into the various components of the air-conditioning plant, being the air-handling units, heat exchanger, ice storage tanks and chiller. The maximal possible discharge and charging rate at each time period (for the different control strategies) is determined using the model. Given the state of charge of the ice storage tank at each time period, it is then possible to calculate chiller power consumption. The power consumed by fans, fan coil units and pumps (in the air-conditioning plant) has not been calculated in the present analysis, however, the model can easily be extended to include such calculations. The ice storage plant model, enabled simulations of the different control strategies to be carried out over building cooling load profiles for summer and winter. Based on a 24-hour planning horizon, optimal control is found to be optimal and the only consistently performing strategy for all seasons. For the 5000 kWh ice storage plant investigated, optimal control yielded 25% energy savings in June and 12% in January, amounting to a potential of R 11 000 per month. Chiller priority control was near optimal in January but consumed 25% more energy than the base case (without storage) in June. Constant proportion control was optimal in January but poorer in June. Storage priority control is found to be optimal in June but the lowest performer in January. The drawback of optimal control and storage priority control, however, is that they require prediction of future cooling loads. The variance when using auto-regressive neural network to predict the load is expected to be in the region of 2% and thus considered acceptable. Chiller priority control and constant proportion control are instantaneous and simple to implement hence their popularity.