This thesis is a study of the design and testing of a positive ion accelerator and necessary vacuum system.

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No description available.

A need was identified for a set of basic design tools for Multi-Effect Distillation (MED) plant evaporators. This led to an investigation into the different types of evaporators as well as further research on horizontal falling film evaporators as used in the MED process. It also included the theory on these types of evaporators. In order not to duplicate existing design tools, an investigation was also performed on some of the tools that are currently available. The first set of tools that were developed were tools, programmed in EES (Engineering Equation Solver), for the vacuum system and the evaporator. These programs can be used to simulate different parameters (like different mass flows and temperatures). That enables the correct selection of components for the vacuum system and can be used to address sizing issues around the evaporator. It can also be used to plan the layout of the plant. The second of the design tools was developed by designing and building a flow pattern test section. From the flow pattern test section a set of curves for the wetted length under different conditions was obtained which can be used in order to design the sieve tray. This set of curves was found to be accurate for municipal as well as seawater and can be used in the design of the sieve tray of the evaporator. Further development can be done by implementing the figures of the wetted length into a simulation package like, for example, Flownex (a system CFD (Computational Fluid Dynamics) code that enables users to perform detail design, analysis and optimization of a wide range of thermal-fluid systems). The background gained from the study done on the evaporator can also be implemented into such a package. This could solve the problem of different design packages by creating a single design package with all of the above mentioned options included. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2009.

A need was identified for a set of basic design tools for Multi-Effect Distillation (MED) plant evaporators. This led to an investigation into the different types of evaporators as well as further research on horizontal falling film evaporators as used in the MED process. It also included the theory on these types of evaporators. In order not to duplicate existing design tools, an investigation was also performed on some of the tools that are currently available. The first set of tools that were developed were tools, programmed in EES (Engineering Equation Solver), for the vacuum system and the evaporator. These programs can be used to simulate different parameters (like different mass flows and temperatures). That enables the correct selection of components for the vacuum system and can be used to address sizing issues around the evaporator. It can also be used to plan the layout of the plant. The second of the design tools was developed by designing and building a flow pattern test section. From the flow pattern test section a set of curves for the wetted length under different conditions was obtained which can be used in order to design the sieve tray. This set of curves was found to be accurate for municipal as well as seawater and can be used in the design of the sieve tray of the evaporator. Further development can be done by implementing the figures of the wetted length into a simulation package like, for example, Flownex (a system CFD (Computational Fluid Dynamics) code that enables users to perform detail design, analysis and optimization of a wide range of thermal-fluid systems). The background gained from the study done on the evaporator can also be implemented into such a package. This could solve the problem of different design packages by creating a single design package with all of the above mentioned options included. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2009.

Made available in DSpace on 2014-12-17T14:13:57Z (GMT). No. of bitstreams: 1 TertulianoAN.pdf: 232411 bytes, checksum: a161cb11c2dc4f0938a8a590c218ab3d (MD5) Previous issue date: 2005-04-12 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Enterocutaneous fistulas are associated with prolonged hospital stay, high morbidity/mortality, and increase in hospital costs. This study aims to describe the use of a vacuum system and normal oral diet in dealing with this problem. Methods: Seventy-four consecutive patients with recent and defined external postoperative fistulas were analyzed. Abdominal imaging was used to exclude abscess and distal obstruction. The fistula tract was sealed with Foley catheter, connected to a negative pressure flask, changed daily for 5, 10 or 15 days, as necessary. Normal oral diet was permitted. Results: No patient died. Serum albumin and transferrin showed significantly higher levels at the end of treatment than at the beginning. The moderate and low-output fistulas had the best results (97% closed). Forty-eight (65%) fistulas closed after five days, 16(22%) after 10 days and 4(5%) after 15 days. Treatment failed in 6(8%) patients, who subsequently underwent surgery. Only one patient with low-output did not close her fistula. The cost of the treatment was US$ 41.75/day and it was considered cost effective. Conclusions: The vacuum system demonstrated good results in the treatment of fistulas. It included simplicity, low cost, short hospital stay, absence of skin breakdown, normal eating, good nutrition and activity patterns / As f?stulas enterocut?neas s?o associadas com hospitaliza??o prolongada, alta morbidez e mortalidade, e aumento dos custos hospitalares. Foi realizado estudo com o objetivo de analisar o uso de um sistema a v?cuo e dieta oral normal para o tratamento dessas f?stulas. M?todos: Foram analisados setenta e quatro pacientes consecutivos portadores de f?stulas enterocut?neas p?s-operat?rias, recentes e bem definidas. Exames abdominais por imagem foram usados para excluir abscesso e obstru??o intestinal distal. O trajeto fistuloso foi fechado com sonda de Foley conectada a um frasco de press?o negativa, que era trocado diariamente por 5, 10 ou 15 dias, conforme necess?rio. Foi permitida dieta oral normal a todos os pacientes. Resultados: Nenhum paciente morreu. Os n?veis de albumina e transferrina s?rica mostraram-se significativamente mais elevados no final do tratamento, quanto comparado com seu in?cio. As fstulas de d?bitos baixo e moderado atingiram os melhores resultados e 97% delas fecharam. Quarenta e oito (65%) f?stulas fecharam ap?s 5 dias, 16(22%) ap?s 10 dias e 4(5%) ap?s 15 dias de tratamento. O sistema falhou em 6(8%) pacientes, que subseq?entemente foram submetidos a interven??o cir?rgica. Apenas em um paciente com fi?stula de baixo d?bito n?o se conseguiu resultado satisfat?rio. O tratamento teve o custo di?rio de R$ 108,55 e foi considerado baixo e efetivo. Conclus?es: O sistema a v?cuo utilizado demonstrou bons resultados no tratamento das f?stulas. Caracterizou-se por simplicidade na execu??o, baixo custo, curto per?odo de hospitaliza??o, aus?ncia de les?es cut?neas, dieta normal, bom estado nutricional, mobilidade e atividades normais dos pacientes

Vacuum technology is ubiquitous in the high tech industries and scientific endeavors. Since vacuum pumps are critical to operation, semiconductor manufacturers desire reliable operations, ability to schedule downtime, and less costly maintenance services. To better cope with difficult maintenance issues, interests in novel fault diagnosis techniques are growing. This study concerns model based fault diagnosis and isolation (MB-FDI) of dry vacuum pumps in the semiconductor industry. Faults alter normal operation of a vacuum pump resulting in performance deviations, discovered by measurements. Simulations using an appropriate mathematical model with suitably chosen parameters can mimic faulty behavior. This research focuses on the construction of a detailed multi-stage dry vacuum pump model for MB-FDI, and the development of a simple and efficient FDI method to analyze common incipient faults such as particulate deposition and gas leak inside the pump. The pump model features 0-D thermo-fluid dynamics, scalable geometric representations of Roots blower, claw pumps and inter-stage port interfaces, a unified pipe model seamlessly connecting from free molecular to turbulent regimes, sophisticated internal leakage model considering true pump geometry and tribological aspects, and systematic assembly of a multi-stage configuration using single stage pump models. Design of a simple FDI technique for the dry vacuum pump includes staged fault simulations using faulty pump models, parametric study of faulty pump behaviors, and design of a health indicator based on classification. The main research contributions include the developments of an accurate multi-stage dry pump model with many features not found in existing pump models, and the design of a simple MB-FDI technique to detect and isolate the common faults found in dry vacuum pumps. The proposed dry pump model can pave the way for the future development of advanced MB-FDI methods, also performance improvement of existing dry vacuum pumps. The proposed fault classification charts can serve as a quick guideline for vacuum pump manufactures to isolate roots causes from faulty symptoms. / text

In this master’s thesis, a preliminary thermodynamic calculation of the turbine is made. Then, the design and location of the vacuum breaker is devised for this turbine. The aim of the master’s thesis is to calculate a time needed to break the vacuum, ie to determine how long it takes to reach the atmospheric pressure inside the turbine and add-on devices. To verify and improve the accuracy of the calculation there are data measured on real projects used.

No description available.

No description available.