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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An integrated architecture for operating procedure synthesis

Soutter, James January 1996 (has links)
The task of creating the operating procedures for a processing plant is time consuming and requires the involvement of key members of the design team. As one of the consequences, the writing of operating procedures is often put off till the final stages of the design process. However, some operability problems will remain hidden in the design until the operating procedure is considered. These problems are expensive to fix because they require undoing some of the design decisions that have already been made. This thesis reports on research into the automatic creation of operating procedures, a field of research sometimes called Operating Procedure Synthesis (OPS). One motivation for OPS research is to develop a tool that can detect operability problems in the design of a plant and thus allow operability problems to be considered earlier in the design process reducing the cost of resolving these problems. Previous OPS systems are generally based around single techniques such as mixed integer linear programming. All the techniques that have been examined in the past are strong in some aspects of OPS and weak in some other aspects. There is no single technique that is strong in all areas of OPS. As a result, no previous OPS system is able to generate all the procedures used as examples in the OPS literature. This thesis presents a new approach to OPS. In this approach, OPS is viewed as a set of distinct but related subtasks. Three subtasks have been identified and examined in this work, namely planning, safety and valve sequencing. Algorithms have been developed to address each of these three subtasks individually. These algorithms have been integrated to form a single OPS system by using a common representation of the operating procedure to be created.
2

Methods to operate and evaluate the performance of a cold-gas CubeSat propulsion system on a magnetically stabilised satellite / Metoder för att använda och utvärdera prestanda för ett kallgas-baserat raketmotorsystem för en magnetiskt stabiliserad nanosatellit

Gonzalez Marin, Victor Alberto January 2020 (has links)
Propulsion systems allow satellites to perform many functionalities in space, such as orbital station keeping, reentry control, attitude control, orbital transferring, rendezvous operation, and even more thrilling, interplanetary travel. Indeed, propulsion systems in satellites have fostered a new favourable era of space exploration and application, therefore, detailed processes to operate propulsion systems need to be developed so that space missions, carrying this valuable system, are completed successfully. The aim of this study is to describe the most relevant operating procedures for the cold gas propulsion system NanoProp 3U, developed by GomSpace, on-board the 3U CubeSat MIST satellite developed by KTH. Procedures, such as power levels, telemetry considerations, propellant mass determination, Fault Detection Isolation and Recovery analysis, and decommissioning plan allow proper operation of NanoProp according to the mission requirements determined for MIST mission. Moreover, this study describes detailed mission experiments to be performed with NanoProp with the objective of assessing the performance delivered by the propulsion system itself, and other on-board subsystems which are required for monitoring and controlling the spacecraft according to the effects generated by the propulsion system. The planning and operation of a propulsion system should be outlined on-ground, during the mission design, so a clear understanding of the characteristics and limitations of the system are highlighted towards the development of a secure and solid space mission. / Framdrivningssystem tillåter satelliter att utföra många funktioner i rymden, som t.ex. att hålla konstant avstånd till en annan rymdfarkost, utlösa återinträde i atmosfären, attitydstyrning, manövrera mellan olika omloppsbanor, och, till och med, interplanetära uppdrag. Framdrivningssystem i satelliter har främjat en ny lovande era av rymdforskning och praktisk tillämpning av rymden, och därför behöver detaljerade, men praktiskt hanterbara, metoder för att operativt använda framdrivningssystem utvecklas. Basen för detta arbete är att beskriva de mest relevanta driftsrutinerna för framdrivningssystemet NanoProp 3U, utvecklat av GomSpace, för användning ombord på MIST-satelliten (en 3U Cubesat) som utvecklats av KTH. Aspekter på NanoProps användning i MIST som förbrukning av elektrisk energi, telemetribehov, drivmedelsmassa, hantering av felfunktioner (upptäckt och avhjälpande) och avveckling av satelliten vid drifttidens slut analyseras i detalj. Dessutom analyserar detta arbete hur detaljerade driftprov kan utföras med NanoProp i syfte att bedöma de prestanda som framdrivningssystemet tillhandahåller och hur dessa prov påverkar och stöds av driften av satellitens övriga delsystem. Det övergripande syftet med detta arbete är således att utveckla en metod för att planera driften av ett framdrivningssystem under ett satellitprojekts definitions- och utvecklingsfaser så att en tydlig förståelse av systemets egenskaper och begränsningar leder till ett säkert och stabilt rymduppdrag.
3

Ignition and Burning Behavior of Modern Fire Hazards: Firebrand Induced Ignition and Thermal Runaway of Lithium-Ion Batteries

Kwon, Byoungchul 26 May 2023 (has links)
No description available.
4

Estratégia de contratação ótima de geradores hidroelétricos considerando os impactos dos procedimentos operativos de curto prazo. / Optimal level of energy contracting strategy of the hydroelectric generators considering the influence of short term operating procedures.

Almeida, Rafael Ribeiro de 21 August 2012 (has links)
O trabalho apresenta uma discussão sobre o nível de contratação ótima dos geradores hidroelétricos participantes do Mecanismo de Realocação de Energia (MRE), considerando a influência dos Procedimentos Operativos de Curto Prazo (POCP). O assim denominado POCP é um conjunto de procedimentos realizados pelo Operador Nacional do Sistema (ONS) para proporcionar mais segurança no atendimento à carga do Sistema Interligado, sendo realizado no período de abril a novembro, durante o Programa Mensal de Operação (PMO). O gerador hidráulico, em função do despacho centralizado e normativo adotado no Brasil, dependendo da quantidade de água que aflui aos reservatórios e do consequente despacho das usinas determinado pelo ONS, fica sujeito às exposições no mercado de curto prazo, decorrentes da diferença entre os contratos de venda do gerador e o montante de garantia física (GF) alocada mensalmente após a realização do MRE. Como o POCP não está incorporado nos modelos de despacho das usinas do setor elétrico, uma alternativa de simulação foi construída e, a partir dos seus resultados, pode-se perceber a interferência do mecanismo em tela nas exposições no mercado de curto prazo e no patamar de risco incorrido. A aplicação do POCP traz um efeito líquido de redução da geração hidrelétrica, pois se diminui a possibilidade de utilizar a capacidade de regularização dos reservatórios, evitando riscos de eventual não recuperação dos reservatórios no período chuvoso. Por outro lado, o procedimento conservador hoje utilizado pode gerar um volume muito maior de vertimentos durante o período úmido, limitando a chance de recuperação financeira dos geradores hidrelétricos que tiveram sua geração reduzida no período seco devido ao despacho antecipado de termelétricas, fatalmente com rebatimentos traduzidos por exposições ao PLD. Por conta de todos os fatores de risco citados, os agentes geradores precisam ajustar sua estratégia ótima de contratação, mantendo a função objetivo de maximizar a receita, condicionado a critérios de risco, que ponderem os fatores citados. Nessa perspectiva, foi analisada a aplicação do POCP no ano de 2010 e seus impactos, além de simular a receita esperada e o risco futuro com e sem a aplicação deste mecanismo. Os resultados mostram o quanto o POCP interfere na receita esperada dos agentes, agregando maiores riscos e alterando-se o nível de contratação ótima. Sendo assim, dependendo do risco que cada agente gerador está disposto a assumir, uma revisão de seu nível de contratação torna-se imperiosa. / This work presents a discussion about the optimal level of energy contracting of the Hydroelectric Generators participants of the Energy Reallocation Mechanism, (MRE - Mecanismo de Realocação de Energia), considering the influence of Short Term Operating Procedures (POCP - Procedimentos Operativos de Curto Prazo). The POCP is a set of procedures performed by the National System Operator (ONS - Operador Nacional do Sistema) to provide more security in the Interconnected System, being carried out from April to November, during the Monthly Programme Operation (PMO - Programa Mensal de Operação). Hydro plants are subject to exposure in short-term market due to the centralized dispatch adopted in Brazil, which depends on the amount of water that flows to the reservoir and on the subsequent dispatch of plants determined by the ONS. The exposure in short-term market, arises from the difference between the Generator sales contracts and the amount of assured energy (GF - Garantia Física) monthly allocated after the MRE. As the POCP is not incorporated into the dispatch models of the electricity sector, an alternative simulation was built and, from its results, we can notice the interference of the mechanism displayed in the short-term market and in the incurred risk level. The application of the POCP brings a net reduction in hydropower generation, because it decreases the possibility of using the regularization capacity of the reservoirs, avoiding any risk of non recovery of the reservoirs during the rainy season. On the other hand, the conservative procedure used today can generate a much larger volume of spilling water during the wet season, limiting the chance of financial recovery of hydroelectric dams that had their generation reduced in the dry season due to the anticipated dispatch of thermoelectric plants, inevitably with repercussions represented by exposure to the PLD (SPOT). Considering all risk factors mentioned, the generating agents have to adjust their optimal strategy for contract level, retaining the objective function to maximize revenue, conditional to risk criteria, which consider the factors mentioned. From this perspective, we analyzed the application of the POCP in 2010 and its impacts, as well as simulated the expected revenue and the future risk with and without the application of this procedure. The results show how the POCP interferes in the expected revenue of the agents, adding greater risks and changing the optimal level of energy contracting. Thus, depending on the risk that each generating agent is willing to take, a review of their contracting level becomes imperative.
5

Estratégia de contratação ótima de geradores hidroelétricos considerando os impactos dos procedimentos operativos de curto prazo. / Optimal level of energy contracting strategy of the hydroelectric generators considering the influence of short term operating procedures.

Rafael Ribeiro de Almeida 21 August 2012 (has links)
O trabalho apresenta uma discussão sobre o nível de contratação ótima dos geradores hidroelétricos participantes do Mecanismo de Realocação de Energia (MRE), considerando a influência dos Procedimentos Operativos de Curto Prazo (POCP). O assim denominado POCP é um conjunto de procedimentos realizados pelo Operador Nacional do Sistema (ONS) para proporcionar mais segurança no atendimento à carga do Sistema Interligado, sendo realizado no período de abril a novembro, durante o Programa Mensal de Operação (PMO). O gerador hidráulico, em função do despacho centralizado e normativo adotado no Brasil, dependendo da quantidade de água que aflui aos reservatórios e do consequente despacho das usinas determinado pelo ONS, fica sujeito às exposições no mercado de curto prazo, decorrentes da diferença entre os contratos de venda do gerador e o montante de garantia física (GF) alocada mensalmente após a realização do MRE. Como o POCP não está incorporado nos modelos de despacho das usinas do setor elétrico, uma alternativa de simulação foi construída e, a partir dos seus resultados, pode-se perceber a interferência do mecanismo em tela nas exposições no mercado de curto prazo e no patamar de risco incorrido. A aplicação do POCP traz um efeito líquido de redução da geração hidrelétrica, pois se diminui a possibilidade de utilizar a capacidade de regularização dos reservatórios, evitando riscos de eventual não recuperação dos reservatórios no período chuvoso. Por outro lado, o procedimento conservador hoje utilizado pode gerar um volume muito maior de vertimentos durante o período úmido, limitando a chance de recuperação financeira dos geradores hidrelétricos que tiveram sua geração reduzida no período seco devido ao despacho antecipado de termelétricas, fatalmente com rebatimentos traduzidos por exposições ao PLD. Por conta de todos os fatores de risco citados, os agentes geradores precisam ajustar sua estratégia ótima de contratação, mantendo a função objetivo de maximizar a receita, condicionado a critérios de risco, que ponderem os fatores citados. Nessa perspectiva, foi analisada a aplicação do POCP no ano de 2010 e seus impactos, além de simular a receita esperada e o risco futuro com e sem a aplicação deste mecanismo. Os resultados mostram o quanto o POCP interfere na receita esperada dos agentes, agregando maiores riscos e alterando-se o nível de contratação ótima. Sendo assim, dependendo do risco que cada agente gerador está disposto a assumir, uma revisão de seu nível de contratação torna-se imperiosa. / This work presents a discussion about the optimal level of energy contracting of the Hydroelectric Generators participants of the Energy Reallocation Mechanism, (MRE - Mecanismo de Realocação de Energia), considering the influence of Short Term Operating Procedures (POCP - Procedimentos Operativos de Curto Prazo). The POCP is a set of procedures performed by the National System Operator (ONS - Operador Nacional do Sistema) to provide more security in the Interconnected System, being carried out from April to November, during the Monthly Programme Operation (PMO - Programa Mensal de Operação). Hydro plants are subject to exposure in short-term market due to the centralized dispatch adopted in Brazil, which depends on the amount of water that flows to the reservoir and on the subsequent dispatch of plants determined by the ONS. The exposure in short-term market, arises from the difference between the Generator sales contracts and the amount of assured energy (GF - Garantia Física) monthly allocated after the MRE. As the POCP is not incorporated into the dispatch models of the electricity sector, an alternative simulation was built and, from its results, we can notice the interference of the mechanism displayed in the short-term market and in the incurred risk level. The application of the POCP brings a net reduction in hydropower generation, because it decreases the possibility of using the regularization capacity of the reservoirs, avoiding any risk of non recovery of the reservoirs during the rainy season. On the other hand, the conservative procedure used today can generate a much larger volume of spilling water during the wet season, limiting the chance of financial recovery of hydroelectric dams that had their generation reduced in the dry season due to the anticipated dispatch of thermoelectric plants, inevitably with repercussions represented by exposure to the PLD (SPOT). Considering all risk factors mentioned, the generating agents have to adjust their optimal strategy for contract level, retaining the objective function to maximize revenue, conditional to risk criteria, which consider the factors mentioned. From this perspective, we analyzed the application of the POCP in 2010 and its impacts, as well as simulated the expected revenue and the future risk with and without the application of this procedure. The results show how the POCP interferes in the expected revenue of the agents, adding greater risks and changing the optimal level of energy contracting. Thus, depending on the risk that each generating agent is willing to take, a review of their contracting level becomes imperative.
6

The legal obligations of retirement fund trustees in respect of section 37c of the Pension Funds Act 24 of 1956

David, Vanashree 08 February 2013 (has links)
Prior to the introduction of section 37C into the Pension Funds Act. 24 of 1956, the benefit payable as a result of the death of a member would devolve in accordance with his last will and testament or the provisions of intestate succession. The advent of section 37C brought a statutory regime which expressly excludes freedom of testation and rather looks to the board of a fund to distribute the death benefit. The board may only pay the dependants of a deceased (either factual or legal) or the persons he has recorded on his nomination form. The section relies on the board to exercise its discretion in a manner which results in an equitable distribution of the death benefit notwithstanding that it does not provide any guidelines as to how this is to be achieved. Accordingly, numerous decisions are challenged by the identified beneficiaries because they are unhappy with the manner in which the board exercised its discretion. This results in complaints being lodged with the Pension Funds Adjudicator. Many such complaints should never have arisen or could have been easily solved by a proper exercise of discretion on the part of the board. The problem is that these complaints are adding to an already burdened office. Adequate training and understanding of the obligations of section 37C would probably result in fewer complaints to the Adjudicator. This dissertation examines whether the determinations which have been issued by the Adjudicator in respect of section 37C indicate a need for such training and understanding and, if they do, what possible remedies there might be to cure such a problem. Recommendations arising from this are that trustees must receive training focused on section 37C and proposed practical protocols to assist a board when exercising its duty to make an equitable distribution. / Jurisprudence / LL.M.
7

The legal obligations of retirement fund trustees in respect of section 37c of the Pension Funds Act 24 of 1956

David, Vanashree 08 February 2013 (has links)
Prior to the introduction of section 37C into the Pension Funds Act. 24 of 1956, the benefit payable as a result of the death of a member would devolve in accordance with his last will and testament or the provisions of intestate succession. The advent of section 37C brought a statutory regime which expressly excludes freedom of testation and rather looks to the board of a fund to distribute the death benefit. The board may only pay the dependants of a deceased (either factual or legal) or the persons he has recorded on his nomination form. The section relies on the board to exercise its discretion in a manner which results in an equitable distribution of the death benefit notwithstanding that it does not provide any guidelines as to how this is to be achieved. Accordingly, numerous decisions are challenged by the identified beneficiaries because they are unhappy with the manner in which the board exercised its discretion. This results in complaints being lodged with the Pension Funds Adjudicator. Many such complaints should never have arisen or could have been easily solved by a proper exercise of discretion on the part of the board. The problem is that these complaints are adding to an already burdened office. Adequate training and understanding of the obligations of section 37C would probably result in fewer complaints to the Adjudicator. This dissertation examines whether the determinations which have been issued by the Adjudicator in respect of section 37C indicate a need for such training and understanding and, if they do, what possible remedies there might be to cure such a problem. Recommendations arising from this are that trustees must receive training focused on section 37C and proposed practical protocols to assist a board when exercising its duty to make an equitable distribution. / Jurisprudence / LL. M.
8

Improving the turnaround maintenance of the Escravos gas plant / Ishekwene, I.V.

Ishekwene, Isaac Victor January 2011 (has links)
According to Oliver (2002) the success of turnaround maintenances is measured in terms of the cost of completion, time, safety performance and the performance of the plant afterwards. The Escravos gas plant (EGP) is a gas processing plant that converts associated gas from Chevron owned crude oil wells to liquefied petroleum gas, natural gas and gas condensate (Chevron intranet. Website assessed on September 14, 2007). According to the EGP plant operations coordinator (See interview Appendix A), the plant undergoes a turnaround maintenance exercise once every two years. The major tasks done during these turnaround maintenances are 1. Change–out of three molecular sieve beds. 2. Servicing of three compressor turbines. 3. Servicing of expander turbo–machinery. 4. Clean–out of fired gas heater tubes and burners. 5. Tie–ins for major upgrades. The EGP management does not involve the contractor personnel that carry out the tasks in the management of the turnaround maintenance. The contractor’s personnel simply follow the work plans and instructions developed by the EGP management. The EGP turnaround management team consists of the coordinator who is the head of the turnaround maintenance team, shift supervisors, maintenance supervisors (rotating equipment maintenance supervisor, instrumentation and electrical maintenance supervisor, and static equipment maintenance supervisors), safety supervisors, maintenance planners, process engineers and construction supervisors. All these listed personnel in the preceding paragraph and the supervisors of the contractor teams participate in the pre–turnaround meetings which happen once a month for the first 10 months of the 12 months leading to the turnaround. The meeting frequency increases to once every two weeks during the last two months leading to the turnaround maintenance. The meeting is held daily during the turnaround maintenance and once every two weeks for the first month after the turnaround maintenance. During the preceding months to the turnaround maintenance, the work scope is defined, the job sequence outlined and schedules are developed. Resources requirements are detailed and procured. During the turnaround maintenance the focus of the turnaround meeting is to discuss potential deviations, observe at–risk behaviors and likely challenges. Plans are then made to address these deviations, challenges and at–risk behaviors. After the turnaround maintenance, “lessons learnt” are captured and the turnaround maintenance is closed out. According to the EGP coordinator (see interview in appendix A), the success of its turnaround maintenance is measured by the time used to complete the turnaround maintenance, the total recordable incident rate during the turnaround maintenance, the days away from work, the lost time injury(LTI) and the cost incurred. Poling et al noted that it is difficult to rate turnaround maintenance projects because no two turnaround maintenances strategies are exactly the same. They iterated that the most common tactics used is benchmarking and that benchmarking enables a company to measure and compare its performance against peer companies in a constructive and confidential manner. They pointed out that the quantitative differences computed between a plant and other similar plants using detailed data taxonomy can provide invaluable information regarding improvement opportunities. This is a way of effectively extending a “lessons learned” exercise across multiple companies. According to then however a critical attribute of effective reliability and maintenance benchmarking is the ability to compare disparate assets; but even small differences for similar plants can alter the value of the comparison. Existing literature indicate that the parameters the gas plant management use to rate the safety of its turnaround maintenance (i.e. the total recordable incident rate, the days away from work and the lost time injury)are reactive in nature. They are otherwise called lagging indicators. Lagging indicators are safety performance metrics that are recorded after the accident or incidents has occurred. For example lost time injury is any work related injury or illness which prevents that person from doing any work day after accident (E&P Consultancy Associates. Website assessed on June 15, 2009). In contrast the other group of metrics called pro–active metrics or leading indicators such as at–risk behaviors, near misses and preventive maintenance not completed are parameters that measure safety performance before accident occurs. Leading indicators gained popularity in the 1930’s after Heinrich postulate his iceberg theory (Wright, 2004). Heinrich’s used the iceberg analogy to explain reactive (lagging) and proactive (leading) indicators. Heinrich likened accident and at–risk behaviors to two parts of an Iceberg; the part you see above water and the part hidden under the water. The size of the iceberg above water is relatively small compared to that under water. The iceberg starts to grow under the water and only after they reach a certain size does part of the ice begin to appear above water. Heinrich believed that accidents are the result of root causes such as at–risk behaviors, inconsistencies, wrong policies, lack of training and lack of information. When the number of accidents that occur in an endeavor is measured you get relatively smaller numerical quantities when compared to the number of at–risk behaviors. Heinrich suggested that to eliminate accidents that occur infrequently, organizations must make effort to eliminate the root causes which occur very frequently. This makes sense because imagine a member of personnel coming to work intoxicated every day. Binging intoxicated at work is an at–risk behavior. The employee is very likely to be involved in an accident at some time as a result of his drinking habit. The number of times he is intoxicated if counted will be huge when compared to the impact of the accident when it does occur. The iceberg theory is supported by work from Bird (1980) and Ludwig (1980) who both attempted to establish the correct ratio of accidents to root causes in different industries. Heinrich suggested a ratio of three hundred incidents to twenty nine minor injuries to one major injury. This researcher chose to use the number of at–risk behavior exhibited by the turnaround maintenance teams to rate the safety performance of tasks despite criticism from individuals like Robotham (2004) who said that from his experience minor incidents do not have the potential to become major accidents and Wright et al (2004). Leading indicators are convenient to analysis because of their relative large quantity. In a turnaround environment, the numbers of accidents that occur are relatively few unlike the number of near misses (Bird, 1980). It is easy to statistically analyze thirty at–risk behaviors than four accidents. In addition Fleming et al (2001) noted that data from industry show much success by companies in the reduction of accidents by efforts at reducing the number of at–risk behaviors, increase the number of safety audits, and reduce the number of closed items from audits etc. Phimister et al made similar claims when they said Near miss programs improve corporate environmental, health and safety performance through the identification of near misses. Existing literature also reveals many theories about management styles and their possible impact on performance. The theories are grouped into trait theories, situational theories and behavioral theories. The trait theories tries to explain management styles by traits of the managers like initiative, wisdom, compassion and ambitious. Situational theories suggest that there is no best management style and managers will need to determine which management style best suit the situation. Behavioral theories explain management success by what successful managers do. Behavioral theorists identify autocratic, benevolent, consultative and participatory management styles. Vroom and Yetton (1973) identified variables that will determine the best management style for any given situation. The variables are; 1. Nature of the problem. Is it simple, hard, complex or clear? 2. Requirements for accuracy. What is the consequence of mistakes? 3. Acceptance of an initiative. Do you want people to use their initiative or not? 4. Time–constraints. How much time do we have to finish the task? 5. Cost constraints. Do we have enough or excess to achieve the objective? A decision model was developed by Vroom and Yago (1988)to help managers determine the best management style for different situations based on the variables listed above (See figure six). They also defined five management style could adopt, namely the; 1. Autocratic I style 2. Autocratic II style. 3. Consultative I style 4. Consultative II style 5. Group II style The autocratic I management style is a management style where the leader solves the problem alone using information that is readily available to him/her, is the normal management style of the Escravos gas plant management in all turnarounds prior to 2009. However the Vroom and Yago model recommends the Consultative II management style for the type of work done during the Escravos gas plant turnaround maintenance. According to Coye et al (1995), participatory management or consultative style II creates a sense of ownership in organization. In this management style the leader shares problem with group members individually, and asks for information and evaluation. Group members do not meet collectively, and leader makes decision alone (Vroom and Yago, 1988). Coye et al believe that this management styles instills a sense of pride and motivate employees to increase productivity. In addition they stated that employees who participate in the decisions of the organization feel like they are a part of a team with a common goal, and find their sense of self–esteem and creative fulfillment heightened. According to Filley et al (1961), Spector and Suttle did not find any significant difference in the output of employees under autocratic and participatory management style. This research studies if and how the Escravos gas plant turnaround maintenance can be improved by changing the management style from autocratic I style to consultative II style. Two tasks in the turnaround were studied; namely the change out of the molecular sieve catalyst beds and the servicing of the turbine engines. The turnaround contractor Techint Nigeria Limited divides the work group into teams responsible for specific tasks. Six teams (team A, B, C, D, E and F) were studied. EGP management will not allow the researcher to study more than these six teams for fear of the research disrupting the work. The tasks completed by these teams are amongst those not on the projects critical path so delays caused by the research will not impact the entire turnaround project provided the float on these activities were not exceeded. They also had the fewest number of personnel, so cost impact of the research work could be easier to manager. Teams A, B and C are different maintenance teams comprising of eight personnel each. They were responsible for changing the EGP molecular sieve beds A, B and C respectively in the 2007 and 2009 turnaround. Their tasks are identical because the molecular sieve beds are identical. Teams E, D and F are also maintenance teams comprising of six personnel each. They were responsible for servicing the EGP turbine engines A, B and C during the 2007 and 2009 turnaround maintenance. Their tasks are also identical because the turbine engines are identical. Consultative management style II is exercised by involving team A and team D in the development of the procedures, processes and job safety analysis of all tasks that they were assigned to complete during the 2009 turnaround maintenance. They were also permitted to participate in the turnaround maintenance meetings and to make contributions in the meetings. In the 2007 turnaround maintenance team A and team D only carried out their tasks. They did not participate in the development of procedures and job safety analysis neither did they participate in the turnaround maintenance meetings. The other four teams; team B, team C, team E and team F are used as experimental controls for the research. They did not participate in the development of the procedures, processes nor the job safety analysis for the tasks in either of the turnaround maintenance. They were also not permitted to attend the daily turnaround meetings. They only completed their tasks based on instructions given to them during the 2007 and 2009 turnaround maintenance. It was necessary to study the experimental control teams as the researcher was not sure whether task repetition, increased knowledge or improved team cohesion would lead to a reduced time or a reduced numbers of at–risk behavior. ix The research tested the hypothesis 1H0 and 1H1 and 2H0and 2H1 at the 0.025 and 0.05 level of significance as follows; Null hypothesis, 1H0: There is no significant difference in the time spent by team A and team Din 2007 when they did not participate in the development of the procedures and processes with the time in 2009 when they did(u1-u2=0). Alternate hypothesis, 1H1: There is a significant difference in the time spent by the team A and Din 2007 when they did not participate in the development of the procedures and processes with the time in 2009 when they did (u1-u2!=0). Null hypothesis, 2H0: There is no significant difference in the number of at–risk behaviors observed to have been exhibited by the team A and team D in 2007 when they did not participate in the development of the procedures and processes with the number in 2009 when they did (u1-u2=0). Alternate hypothesis, 2H1: There is a significant difference in the number of at–risk behaviors observed to have been exhibited by the team A and team D in 2007 when they did not participate in the development of the procedures and processes with the number in 2009 when they did (u1-u2!=0). The student t test was used to analyze these times and number of at–risk behavior. At the 0.025 and the 0.05 level of significance, the data show that there is no difference in the times all the teams used to complete their task in 2007 and in 2009. The researcher concludes that a change in the management style from autocratic I style to consultative II style did not lead to a reduction in the time used by any team to complete their task. However at the 0.025 and the 0.05 level of significance, there is a significant difference in the number of at–risk behaviors of the research team A and team D. There is however no significant difference in the number of at–risk behavior of the control team B, team C, team E and team F at the same level of significance. The researcher concludes that a change in the management style from autocratic I style to consultative II style lead to a reduction in the number of at–risk behavior of team A and team D. In addition the reduction in the number of at–risk behavior of team A and team D could not have been because of task repetition, increased knowledge or improved team cohesion since there is no significant difference in the number of at–risk behavior exhibited by team B, team C, team E and team F. The research can be used by the Escravos gas plant management and the management of any similar process plant to fashion out more cost effective, time effective and safer methods for carrying out their turnaround maintenance. A change in management styles may just be a better approach to improving productivity than giving financial incentives to contractors and personnel. Changes in management style will have to be managed. The change must be gradual because sudden change can be detrimental as people may just need to understand and adapt to the change. The turnaround personnel must also understand the intent so as to prevent conflicts. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2012.
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Improving the turnaround maintenance of the Escravos gas plant / Ishekwene, I.V.

Ishekwene, Isaac Victor January 2011 (has links)
According to Oliver (2002) the success of turnaround maintenances is measured in terms of the cost of completion, time, safety performance and the performance of the plant afterwards. The Escravos gas plant (EGP) is a gas processing plant that converts associated gas from Chevron owned crude oil wells to liquefied petroleum gas, natural gas and gas condensate (Chevron intranet. Website assessed on September 14, 2007). According to the EGP plant operations coordinator (See interview Appendix A), the plant undergoes a turnaround maintenance exercise once every two years. The major tasks done during these turnaround maintenances are 1. Change–out of three molecular sieve beds. 2. Servicing of three compressor turbines. 3. Servicing of expander turbo–machinery. 4. Clean–out of fired gas heater tubes and burners. 5. Tie–ins for major upgrades. The EGP management does not involve the contractor personnel that carry out the tasks in the management of the turnaround maintenance. The contractor’s personnel simply follow the work plans and instructions developed by the EGP management. The EGP turnaround management team consists of the coordinator who is the head of the turnaround maintenance team, shift supervisors, maintenance supervisors (rotating equipment maintenance supervisor, instrumentation and electrical maintenance supervisor, and static equipment maintenance supervisors), safety supervisors, maintenance planners, process engineers and construction supervisors. All these listed personnel in the preceding paragraph and the supervisors of the contractor teams participate in the pre–turnaround meetings which happen once a month for the first 10 months of the 12 months leading to the turnaround. The meeting frequency increases to once every two weeks during the last two months leading to the turnaround maintenance. The meeting is held daily during the turnaround maintenance and once every two weeks for the first month after the turnaround maintenance. During the preceding months to the turnaround maintenance, the work scope is defined, the job sequence outlined and schedules are developed. Resources requirements are detailed and procured. During the turnaround maintenance the focus of the turnaround meeting is to discuss potential deviations, observe at–risk behaviors and likely challenges. Plans are then made to address these deviations, challenges and at–risk behaviors. After the turnaround maintenance, “lessons learnt” are captured and the turnaround maintenance is closed out. According to the EGP coordinator (see interview in appendix A), the success of its turnaround maintenance is measured by the time used to complete the turnaround maintenance, the total recordable incident rate during the turnaround maintenance, the days away from work, the lost time injury(LTI) and the cost incurred. Poling et al noted that it is difficult to rate turnaround maintenance projects because no two turnaround maintenances strategies are exactly the same. They iterated that the most common tactics used is benchmarking and that benchmarking enables a company to measure and compare its performance against peer companies in a constructive and confidential manner. They pointed out that the quantitative differences computed between a plant and other similar plants using detailed data taxonomy can provide invaluable information regarding improvement opportunities. This is a way of effectively extending a “lessons learned” exercise across multiple companies. According to then however a critical attribute of effective reliability and maintenance benchmarking is the ability to compare disparate assets; but even small differences for similar plants can alter the value of the comparison. Existing literature indicate that the parameters the gas plant management use to rate the safety of its turnaround maintenance (i.e. the total recordable incident rate, the days away from work and the lost time injury)are reactive in nature. They are otherwise called lagging indicators. Lagging indicators are safety performance metrics that are recorded after the accident or incidents has occurred. For example lost time injury is any work related injury or illness which prevents that person from doing any work day after accident (E&P Consultancy Associates. Website assessed on June 15, 2009). In contrast the other group of metrics called pro–active metrics or leading indicators such as at–risk behaviors, near misses and preventive maintenance not completed are parameters that measure safety performance before accident occurs. Leading indicators gained popularity in the 1930’s after Heinrich postulate his iceberg theory (Wright, 2004). Heinrich’s used the iceberg analogy to explain reactive (lagging) and proactive (leading) indicators. Heinrich likened accident and at–risk behaviors to two parts of an Iceberg; the part you see above water and the part hidden under the water. The size of the iceberg above water is relatively small compared to that under water. The iceberg starts to grow under the water and only after they reach a certain size does part of the ice begin to appear above water. Heinrich believed that accidents are the result of root causes such as at–risk behaviors, inconsistencies, wrong policies, lack of training and lack of information. When the number of accidents that occur in an endeavor is measured you get relatively smaller numerical quantities when compared to the number of at–risk behaviors. Heinrich suggested that to eliminate accidents that occur infrequently, organizations must make effort to eliminate the root causes which occur very frequently. This makes sense because imagine a member of personnel coming to work intoxicated every day. Binging intoxicated at work is an at–risk behavior. The employee is very likely to be involved in an accident at some time as a result of his drinking habit. The number of times he is intoxicated if counted will be huge when compared to the impact of the accident when it does occur. The iceberg theory is supported by work from Bird (1980) and Ludwig (1980) who both attempted to establish the correct ratio of accidents to root causes in different industries. Heinrich suggested a ratio of three hundred incidents to twenty nine minor injuries to one major injury. This researcher chose to use the number of at–risk behavior exhibited by the turnaround maintenance teams to rate the safety performance of tasks despite criticism from individuals like Robotham (2004) who said that from his experience minor incidents do not have the potential to become major accidents and Wright et al (2004). Leading indicators are convenient to analysis because of their relative large quantity. In a turnaround environment, the numbers of accidents that occur are relatively few unlike the number of near misses (Bird, 1980). It is easy to statistically analyze thirty at–risk behaviors than four accidents. In addition Fleming et al (2001) noted that data from industry show much success by companies in the reduction of accidents by efforts at reducing the number of at–risk behaviors, increase the number of safety audits, and reduce the number of closed items from audits etc. Phimister et al made similar claims when they said Near miss programs improve corporate environmental, health and safety performance through the identification of near misses. Existing literature also reveals many theories about management styles and their possible impact on performance. The theories are grouped into trait theories, situational theories and behavioral theories. The trait theories tries to explain management styles by traits of the managers like initiative, wisdom, compassion and ambitious. Situational theories suggest that there is no best management style and managers will need to determine which management style best suit the situation. Behavioral theories explain management success by what successful managers do. Behavioral theorists identify autocratic, benevolent, consultative and participatory management styles. Vroom and Yetton (1973) identified variables that will determine the best management style for any given situation. The variables are; 1. Nature of the problem. Is it simple, hard, complex or clear? 2. Requirements for accuracy. What is the consequence of mistakes? 3. Acceptance of an initiative. Do you want people to use their initiative or not? 4. Time–constraints. How much time do we have to finish the task? 5. Cost constraints. Do we have enough or excess to achieve the objective? A decision model was developed by Vroom and Yago (1988)to help managers determine the best management style for different situations based on the variables listed above (See figure six). They also defined five management style could adopt, namely the; 1. Autocratic I style 2. Autocratic II style. 3. Consultative I style 4. Consultative II style 5. Group II style The autocratic I management style is a management style where the leader solves the problem alone using information that is readily available to him/her, is the normal management style of the Escravos gas plant management in all turnarounds prior to 2009. However the Vroom and Yago model recommends the Consultative II management style for the type of work done during the Escravos gas plant turnaround maintenance. According to Coye et al (1995), participatory management or consultative style II creates a sense of ownership in organization. In this management style the leader shares problem with group members individually, and asks for information and evaluation. Group members do not meet collectively, and leader makes decision alone (Vroom and Yago, 1988). Coye et al believe that this management styles instills a sense of pride and motivate employees to increase productivity. In addition they stated that employees who participate in the decisions of the organization feel like they are a part of a team with a common goal, and find their sense of self–esteem and creative fulfillment heightened. According to Filley et al (1961), Spector and Suttle did not find any significant difference in the output of employees under autocratic and participatory management style. This research studies if and how the Escravos gas plant turnaround maintenance can be improved by changing the management style from autocratic I style to consultative II style. Two tasks in the turnaround were studied; namely the change out of the molecular sieve catalyst beds and the servicing of the turbine engines. The turnaround contractor Techint Nigeria Limited divides the work group into teams responsible for specific tasks. Six teams (team A, B, C, D, E and F) were studied. EGP management will not allow the researcher to study more than these six teams for fear of the research disrupting the work. The tasks completed by these teams are amongst those not on the projects critical path so delays caused by the research will not impact the entire turnaround project provided the float on these activities were not exceeded. They also had the fewest number of personnel, so cost impact of the research work could be easier to manager. Teams A, B and C are different maintenance teams comprising of eight personnel each. They were responsible for changing the EGP molecular sieve beds A, B and C respectively in the 2007 and 2009 turnaround. Their tasks are identical because the molecular sieve beds are identical. Teams E, D and F are also maintenance teams comprising of six personnel each. They were responsible for servicing the EGP turbine engines A, B and C during the 2007 and 2009 turnaround maintenance. Their tasks are also identical because the turbine engines are identical. Consultative management style II is exercised by involving team A and team D in the development of the procedures, processes and job safety analysis of all tasks that they were assigned to complete during the 2009 turnaround maintenance. They were also permitted to participate in the turnaround maintenance meetings and to make contributions in the meetings. In the 2007 turnaround maintenance team A and team D only carried out their tasks. They did not participate in the development of procedures and job safety analysis neither did they participate in the turnaround maintenance meetings. The other four teams; team B, team C, team E and team F are used as experimental controls for the research. They did not participate in the development of the procedures, processes nor the job safety analysis for the tasks in either of the turnaround maintenance. They were also not permitted to attend the daily turnaround meetings. They only completed their tasks based on instructions given to them during the 2007 and 2009 turnaround maintenance. It was necessary to study the experimental control teams as the researcher was not sure whether task repetition, increased knowledge or improved team cohesion would lead to a reduced time or a reduced numbers of at–risk behavior. ix The research tested the hypothesis 1H0 and 1H1 and 2H0and 2H1 at the 0.025 and 0.05 level of significance as follows; Null hypothesis, 1H0: There is no significant difference in the time spent by team A and team Din 2007 when they did not participate in the development of the procedures and processes with the time in 2009 when they did(u1-u2=0). Alternate hypothesis, 1H1: There is a significant difference in the time spent by the team A and Din 2007 when they did not participate in the development of the procedures and processes with the time in 2009 when they did (u1-u2!=0). Null hypothesis, 2H0: There is no significant difference in the number of at–risk behaviors observed to have been exhibited by the team A and team D in 2007 when they did not participate in the development of the procedures and processes with the number in 2009 when they did (u1-u2=0). Alternate hypothesis, 2H1: There is a significant difference in the number of at–risk behaviors observed to have been exhibited by the team A and team D in 2007 when they did not participate in the development of the procedures and processes with the number in 2009 when they did (u1-u2!=0). The student t test was used to analyze these times and number of at–risk behavior. At the 0.025 and the 0.05 level of significance, the data show that there is no difference in the times all the teams used to complete their task in 2007 and in 2009. The researcher concludes that a change in the management style from autocratic I style to consultative II style did not lead to a reduction in the time used by any team to complete their task. However at the 0.025 and the 0.05 level of significance, there is a significant difference in the number of at–risk behaviors of the research team A and team D. There is however no significant difference in the number of at–risk behavior of the control team B, team C, team E and team F at the same level of significance. The researcher concludes that a change in the management style from autocratic I style to consultative II style lead to a reduction in the number of at–risk behavior of team A and team D. In addition the reduction in the number of at–risk behavior of team A and team D could not have been because of task repetition, increased knowledge or improved team cohesion since there is no significant difference in the number of at–risk behavior exhibited by team B, team C, team E and team F. The research can be used by the Escravos gas plant management and the management of any similar process plant to fashion out more cost effective, time effective and safer methods for carrying out their turnaround maintenance. A change in management styles may just be a better approach to improving productivity than giving financial incentives to contractors and personnel. Changes in management style will have to be managed. The change must be gradual because sudden change can be detrimental as people may just need to understand and adapt to the change. The turnaround personnel must also understand the intent so as to prevent conflicts. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2012.
10

Stavebně technologický projekt objektů skládky Úholičky / Constructional technologic project of objects at dump Úholičky

Doubek, Rostislav January 2015 (has links)
In this diploma thesis two steel frame objects of a waste dump in Úholičky are solved. The aim is to resolve the chosen parts of a construction-technological project. The main topics for selected technological phases are transportation, bill of quantities, technological regulations, construction organization’s principles, time schedule, machinery, control and testing plan, work safety and worker’s health protection. These topics are prepared for the technological phases of ground works, fundamental contruction, upper load-bearing structure, construction of the floor and sheathing of the object. The thesis has also other parts which include static solution of a prestressed unit, budget by items, calculation of the object’s maintenance cost, handbook for bulding’s occupancy and proposal of construction contract.

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