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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

Cost and time effective DSM on mine compressed air systems / R. Joubert

Joubert, Hercules Phillipus Roedolf January 2010 (has links)
Implementing demand side management (DSM) is expensive and often time consuming. Eskom grants subsidies for DSM projects based on the proposed savings. The subsidy granted is not always adequate to fund all the required control equipment to achieve the desired saving. This study focuses on alternative cost– and time–effective methods to implement DSM on gold mines, specifically on the compressed–air systems where the infrastructure is inadequate, worn out or outdated. The compressors generating compressed air for mining are one of the largest electricity consumer at gold mines. By optimising the energy consumption of these compressed–air systems, the largest potential demand reduction can be achieved. This will lighten the demand load on the already overloaded national power grid. Compressed air at gold mines is mainly used for production purposes, thus the majority of savings on these systems need to be achieved during non–production hours. Fixing air leaks, optimising compressor control, meticulous planning of implementation locations and controlling air usage are all methods that were investigated to achieve alternative cost– and time–effective methods to implement DSM on mine compressed–air systems. The methods were implemented by an Energy Services Company (ESCo) at four different mines. The results achieved from these case studies are documented and discussed in this study. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2011.
2

Cost and time effective DSM on mine compressed air systems / R. Joubert

Joubert, Hercules Phillipus Roedolf January 2010 (has links)
Implementing demand side management (DSM) is expensive and often time consuming. Eskom grants subsidies for DSM projects based on the proposed savings. The subsidy granted is not always adequate to fund all the required control equipment to achieve the desired saving. This study focuses on alternative cost– and time–effective methods to implement DSM on gold mines, specifically on the compressed–air systems where the infrastructure is inadequate, worn out or outdated. The compressors generating compressed air for mining are one of the largest electricity consumer at gold mines. By optimising the energy consumption of these compressed–air systems, the largest potential demand reduction can be achieved. This will lighten the demand load on the already overloaded national power grid. Compressed air at gold mines is mainly used for production purposes, thus the majority of savings on these systems need to be achieved during non–production hours. Fixing air leaks, optimising compressor control, meticulous planning of implementation locations and controlling air usage are all methods that were investigated to achieve alternative cost– and time–effective methods to implement DSM on mine compressed–air systems. The methods were implemented by an Energy Services Company (ESCo) at four different mines. The results achieved from these case studies are documented and discussed in this study. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2011.
3

Investigating human pharmaceutical compounds present in municipal and hospital wastewaters and options for their removal

Al Qarni, Hamed M. January 2015 (has links)
Pharmaceutical compounds comprise a wide range of substances that are consumed in large quantities by modern societies and are generally released into local sewer networks through excretion. This research aimed to identify the factors affecting the removal efficiencies of these compounds in biological wastewater treatment plants (WWTPs) under different environmental conditions. Of the pharmaceutical compounds selected for this study, the highest influent concentrations measured in municipal wastewater treatment plants (MWWTPs) were for paracetamol, naproxen and bezafibrate (> 1 μg/L), followed by carbamazepine, atenolol, lidocaine, sulfamethoxazole and NACS (<1 μg/L). In hospital wastewater treatment plants (HWWTPs), the highest concentrations measured were for paracetamol and caffeine (> 10 μg/L), followed by ciprofloxacin and NACS (1–6 μg/L), and finally bezafibrate, carbamazepine, atenolol, lidocaine, clarithromycin and sulfamethoxazole (< 1μg/L). Antibiotic drugs were detected in HWWTPs, but rarely detected in MWWTPs. In general, the hospital wastewaters contained relatively higher levels of pharmaceuticals than municipal wastewaters. The removal efficiencies of the pharmaceutical compounds ranged widely. This was found to be related to characteristics and operational parameters of the individual WWTPs. The MWWTPs that utilized long aeration and biomass retention times (HRT,SRT), as evidenced by the occurrence of complete nitrification, were more efficient at removing paracetamol, naproxen, bezafibrate and atenolol, than the non-nitrifying plants with relatively shorter HRT and SRT. HWWTPs that operated under elevated ambient temperatures (> 26°C) achieved higher removal efficiencies (90%) for several compounds, including paracetamol, caffeine, sulfamethoxazole, ciprofloxacin, clarithromycin, NACS, atenolol, carbamazepine and lidocaine. In addition to the elevated ambient temperatures, elevated HRT and SRT and less dilution can lead to increased active biomass and can result in higher removal rates for the pharmaceutical compounds. Overall, the removal efficiencies of pharmaceuticals in WWTPs have been correlated to the type of treatment plant, the plants’ operational parameters (HRT, SRT), the climatic conditions (temperature and dilution effect of rainfall) and characteristics of the micropollutants (type and concentration). Aerobic and anaerobic batch biodegradation experiments were conducted to observe the removal of paracetamol, naproxen, ibuprofen and sulfamethoxazole at various SRTs. The biodegradation rates varied widely ranging from poor, to moderate, to high, depending on the SRT. Paracetamol was highly biodegradable under both aerobic and anaerobic conditions. Sulfamethoxazole was poorly biodegradable under aerobic conditions but highly biodegradable under anaerobic conditions. Relatively slow biodegradation rates were observed for ibuprofen and naproxen under both conditions; longer microbial adaptation periods for these two compounds were probably required. The most important factor affecting the removal of the compounds was the SRT. Therefore, the conclusion was drawn that combining anaerobic and aerobic systems with longer SRT and HRT could bring about significant reductions in the emissions of these contaminants into the environment via WWTPs; this is also a cost-effective option.
4

Methods for Reducing the Complexity of Geometrical Structures Based on CFD Programming : Time Efficient Simulations Based on Volume Forces Coupled with Single and Two-phase Flow

Rezk, Kamal January 2014 (has links)
Throughout recent years, computer based programs have been applied to solve and analyse industrial problems encountered global fields such as automobile design for reduction of CO2-gas, designing wind parks aimed at increasing power output etc. One of these developed programs is Computational Fluid Dynamics (CFD) which numerically solves complex flow behaviour based on computer power. As there is an ongoing expansion of CFD usage in industry, certain issues need to be addressed as they are becoming more frequently encountered. The general demand for the simulation of larger control volumes and more advanced flow processes result in an extensive requirement of computer resources. Moreover, the implementation of commercial CFD codes in small-scaled industrial companies seems to generally be utilised as a black box based on the knowledge of fluid mechanic theory. Increased partnerships between industry and the academic world involving various CFD based design processes generally yield to a verbal communication interface, which is a crucial step in the process given the level of dependency between both sides. Based on these notions, a method for establishing time efficient CFD-models with implementation of volume forces as sink terms in the momentum equation is presented. The internal structure, or parts of the structure, in the simulation domain is removed which reduces the geometrical complexity and along with it, computational demand.  These models are the basis of assessing the benefits of utilizing a numerical based design process in industry in which the CFD code is used as a communication tool for knowledge sharing with counterparts in different fields. / As there is an ongoing expansion of CFD usage in industry, certain issues need to be addressed as they are becoming more frequently encountered. The general demand for the simulation of larger control volumes and more advanced flow processes result in an extensive requirement of computer resources. Moreover, the implementation of commercial CFD codes in small-scaled industrial companies seems to generally be utilised as a black box based on the knowledge of fluid mechanic theory. Increased partnerships between industry and the academic world involving various CFD based design processes generally yield to a verbal communication interface, which is a crucial step in the process given the level of dependency between both sides. Based on these notions, a method for establishing time efficient CFD-models with implementation of volume forces as sink terms in the momentum equation is presented. The internal structure, or parts of the structure, in the simulation domain is removed which reduces the geometrical complexity and along with it, computational demand.  These models are the basis of assessing the benefits of utilizing a numerical based design process in industry in which the CFD code is used as a communication tool for knowledge sharing with counterparts in different fields.
5

Efficient data transport in wireless sensor networks.

Zhang, Haibo January 2009 (has links)
Providing efficient data transport is one of the uppermost objectives in the design of wireless sensor networks (WSNs) since the primary role for each sensor is to report the sensed data to the data sink(s). This thesis focuses on designing efficient data transport schemes for WSNs in the dimensions of energy consumption and time respectively. The developed schemes can be directly applied in a number of applications such as intrusion detection, target tracking, environment monitoring, etc., and can be further extended to underwater acoustic sensor networks and unmanned aerial vehicles (UAVs) networks. With the development of WSN technologies, new challenging research problems such as real-time streaming data gathering and intelligent data communication are emerging. This thesis provides useful foundation for designing next-generation data transport schemes for WSNs. Energy is the most important resource in WSNs because sensor nodes are commonly powered by small batteries, and energy is directly related to the lifetime of nodes and the network. In this thesis, energy-efficient data transport schemes are designed for two major types of WSNs: event-driven sensor networks and time-driven sensor networks. A novel on-line routing scheme called EBGR (Energy-efficient Beaconless Geographic Routing) is designed for event-driven sensor networks characterized by dynamic network topology. The main advantage of EBGR is that it can provide energy-efficient sensor-to-sink routing without any prior neighborhood knowledge. Moreover, the total energy consumption for sensor-to-sink data delivery under EBGR has an upper bound. Time-driven sensor networks, in which all sensors periodically report the sensed data to the sink(s), have been widely used for environment monitoring applications. Unbalanced energy consumption is an inherent problem in time-driven sensor networks. An efficient data gathering scheme, called EBDG (Energy-Balanced Data Gathering), is designed to balance energy consumption for the goal of maximizing network lifetime. Combing all advantages of corona-based network division,mixed-routing and data aggregation, EBDG can prolong network lifetime by an order of magnitude compared with conventional schemes. Time-efficient data transport is another critical issue in WSNs since the data generated by the sensor nodes may become outdated after a certain time interval. This thesis focuses on the problem of providing real-time data gathering in time-driven sensor networks. A novel data gathering scheme based on random access is proposed with the objective to minimize the average duration for completing one round of data gathering. Fully localized solutions have been designed for both linear networks and tree networks. A simple data gathering protocol called RADG (Random Access Data Gathering) is designed. Simulation results show that RADG outperforms CSMA based schemes when the size of the data packets is small. / Thesis (Ph.D.) -- University of Adelaide, School of Computer Science, 2009
6

Development of a reliable and time-efficient digital production process of encrypted intelligent keys : Embedded systems and software development

Almario Strömblad, Fredrik, Svensson, Primus January 2022 (has links)
Smart keys are increasing in popularity due to the many benefits they bring. Access control and overview have never been more efficient than it is today. This thesis project automates the digital production of a new line of keys. Automating this production process improves the production in scalability, reliability, and efficiency. This report includes background research on critical components, methodologies to solve presented subproblems, the results of this project, and a discussion providing insight into the possible benefits of using an automated development line. This automation’s core elements are an integrated circuit holding a microcontroller, hardware components, and a graphical user interface. This project results in an automated production process capable of producing smart keys more efficiently than today. A report containing the most common errors using this production process and suggestions to improve scalability, reliability, and efficiency further. / De många fördelar smarta nycklar bidrar med gör att de snabbt ökar i popularitet. Åtkomst och översikt över tillgång har aldrig varit så effektivt som det är idag. Detta examensarbete automatiserar den digitala produktionen av en ny serie elektroniska nycklar. Genom att automatisera den här processen kommer produktionens skalbarhet, pålitlighet och effektivitet att öka. Den här rapporten innehåller bakgrundsundersökningar gällande kritiska områden för utvecklingen, metoder för att lösa problemställningar, projektets resultat samt en diskussion gällande möjliga fördelar av produktionsautomatisering. Grundelementen i den här automatiseringen är ett kretskort med en mikrokontroller, hårdvarukomponenter samt ett grafiskt användargränssnitt. Projektet resulterar i en produktionsprocess kapabel att producera elektroniska nycklar effektivare än tidigare möjligt samt en rapport innehållande de mest förekommande produktionsfelen relaterade till den automatiserade processen. Rapporten innehåller även förslag på förbättringar för att ytterligare öka skalbarhet, pålitlighet och effektivitet.
7

Faktorer som påverkar hanteringen av tungt och otympligt gods : En fallstudie på ett tredjepartslogistikföretag

Elg, Nellie, Högman, Rebecka January 2023 (has links)
Bakgrund: Under de senaste decennierna har behovet gällande effektivare logistikhantering inom alla branscher ökat. Detta härstammar bland annat från förändrade ekonomiska förutsättningar, geopolitiska omvälvningar och utvidgade globala försörjningskedjor. Den interna logistiken har en central roll för att effektivisera interna logistikaktiviteter som till stor del avser ett företags lager, färdigvarulager och godshantering. En bidragande faktor som avgör svårighetsgraden för dessa aktiviteter är produktens fysiska utformning, då tyngre och större föremål kräver mer resurser, såsom planering och hantering. Dock med dagens föränderliga marknad och dess tillhörande osäkerhet, blir påfrestningarna för företag och deras logistik- och lagerplanering mer påtagliga. Syftet: Syftet med denna studie är att undersöka hanteringen av tungt och otympligt gods i färdigvarulagret för att tidseffektivisera lageraktiviteterna som påverkar utlastningskapaciteten. Metod: Det har utförts en fallstudie på ett företag beläget i Gävle kommun, som i denna studie kallas för Företag X. För att kunna undersöka kring det valda ämnet har även ett till företag varit aktuell till denna fallstudie, även det företaget är beläget i Gävle kommun och kallas i denna studie för Företag Y. Genom observationer på Företag Y, intervjuer med personal från Företag Y, samt skriftlig och fysisk kontakt med personal på Företag X har empiriska data samlats in. En kvalitativ deduktiv ansats har använts för att besvara studiens syfte och frågeställning. Empiri: Från produktionen på Företag X till utlastningen på Företag Y är det många medverkande aktörer som alla har en påverkan på utlastningskapaciteten. Det sker även tre olika betydande aktiviteter innan kund får sina produkter, dessa är inlagring, preppning och direktlast/förlast. I dagsläget är det avtalat att Företag Y ska hantera utlastningen av 13 lastbilar per dag åt Företag X. Dock finns det en ojämn spridning kring antalet lastbilar som ankommer per dag samt deras ankomsttider. Slutsats: Studien påvisar att lageraktiviteterna som påverkar utlastningskapaciteten kunna tidseffektiviseras om slottidsbokningssystem, ett mer utvecklat lagerhanteringssystem samt rutiner kring inlagringen infördes, även att all tillgänglig resurs utnyttjades. / Background: In recent decades, more efficient logistics management has been increasingly required in all industries. This comes from, among other things, changed economic conditions, geopolitical upheavals and extended global supply chains. Internal logistics has a central role when the internal logistics activities are going to get more effective. Those internal logistics activities are mainly about a company's warehouse, finished goods warehouse and goods handling. A contributing factor that determines the degree of difficulty of these activities is the physical design of the product, as heavier and larger objects require more resources, such as planning and handling. However, with today's changing market and its associated uncertainty, the stresses on companies and their logistics and inventory planning are becoming more apparent. Purpose: The purpose of this study is to investigate the handling of heavy and unwieldy goods in the finished goods warehouse in order to make the warehouse activities that affect the loading capacity time-efficient.  Method: During this study we have implemented a case study on a company located in Gävle, that is referred to in this study as Company X. In order to investigate the chosen topic, another company has also been relevant to this case study, that company is also located in Gävle and is referred to in this study as Company Y. Through observations at Company Y, interviews with personnel from Company Y, as well as written and physical contact with personnel at Company X, the empirical data has been collected. A qualitative deductive approach has been used to answer the purpose and question of the study. Empiricism: From the production at Company X to the utilization at Company Y there are many participating actors who all have an impact on the loading capacity. There are also three different significant activities before the customer receives their products, which is storage, prepping and directloading/preloading. Currently is has been agreed that Company Y will handle the loading of 13 trucks per day for Comapny X. However, there is an uneven spread regarding the number of trucks that arrive per day and their arrival times.  Conclusion: The study shows that the warehouse activities that affect the loading capacity can be time-efficient if a slot time booking system, a more developed warehouse management system and routines regarding the storage were introduced, also that all available resources were utilized.
8

The efficacy of alternative dispute resolution (ADR) in labour dispute resolution : a critical comparative analysis of Botswana, South Africa and Zimbabwe

Bushe, Bernard January 2019 (has links)
This Master of Laws dissertation is a treatise of “The efficacy of Alternative Dispute Resolution (ADR) in labour disputes: a critical comparative analysis of Botswana, South Africa (RSA) and Zimbabwe.” Alternative Dispute Resolution hereinafter referred to as (“ADR”) has attracted so much research ado worldwide with policy makers alive to its possibilities in so far as it ought to shed off the burden of the courts in handling disputes. Courts are considered inundated with unresolved cases taking many years to finalise. ADR is therefore touted, not only the panacea, but the cheaper, efficient and effective alternative to normal court process. This study was saddled with the common challenges of definition, scope and methodology as does most scientific studies, especially to locate the concept ADR in the plethora of views from prominent exponent-s of the discipline. This study labored on the considered view that ADR is essentially an ‘out of court settlement approach to dispensing with disputes involving an attempt by disputants to rope in an impartial third party to aid finality to the respective wrangle. The lack of a methodological approach to treat this subject matter, made this study more challenging. The study had to therefore rely on a hypothetical model developed after gleaning through various scholarly views 1 that sought to treat the subject of ADR efficacy in labour dispute resolution. The study contented with the strongly held view 2 that ADR is an efficacious approach in resolving disputes outside the court system. As to whether this was the case in Botswana, RSA and Zimbabwe in so far as labour dispute resolution is concerned was the major challenge this study was seized with? A model was formulated which envisaged that efficaciousness of ADR may be achieved if three conditions or criteria are present within a jurisdiction, namely (1) ADR Background Conditions that comprise (a) adequate legislative and political support; (b) Supportive institutional and cultural norms, (c) adequate and competent manpower, (d) sufficient funding support, and (e) power-parity of disputants; (2) ADR Program Design comprising of (a) Planning and preparation and (b) Operations and implementation and finally (3) ADR Measures (a) Client satisfaction; (b) Time efficient; (c) Cost saving and (d) Settlement & enforcement. This study measured the situations obtaining in the three countries using these three-pronged criteria. In all three measures3 this study found that although all the three countries still have a long way before their ADR became as efficacious as would be reasonably possible, RSA has made many strides such as legislative enactments immediately upon attaining independence that sought to address the injustices of the past and thereby installing structures for enforcing industrial democracy 4, while Botswana and Zimbabwe took 5 years 5 and over 10 years 6 respectively after attaining independence. RSA established an independent body for dispensing with labour dispute settlement7 while Botswana8 and Zimbabwe 9 are still reluctant to do so, relying rather on their labour ministries often marinated in bureaucratic bottlenecks hence stalling efficacy of ADR. While RSA makes effort to provide adequate and competent manpower because of sufficient funding, Botswana and Zimbabwe still struggle to dispense with disputes under their labour departments who are either inadequately skilled or also accused of favouritism in the case of Zimbabwe.10 All the three countries are regarded as unequal societies which tends to sway the power-parity of disputants with capitalists still wielding unbridled powers in dispute outcomes. South Africa enacted section 143 to the Labour Relations Act 11 which empowers the Director of CCMA to certify an arbitral award, giving it the same force as an order of the Magistrate Court. This has cut off the time and administrative burden of having to register an arbitral award with the court so as to obtain writs of executions and enforce it, a practice which is still prevalent in Zimbabwe. The Department of Labour in South Africa has made funding available to the CCMA to assist employees who are not in a financial position to enforce awards in their favour.12 The funding is aimed at employees who are too indigent to afford the costs of enforcement.13 These employees are deemed to be: (a) Employees who earn below the earnings threshold (currently at R205 433.30 per annum) – proof of income will be required by the CCMA. There is no record regarding enforcement or ease of enforcement of ADR outcomes in Botswana and Zimbabwe or at least this study is aware of. The governments of Botswana and Zimbabwe have been accused of using a heavy hand in determining wages, the right to strike and often curtailing union power through declaring certain sectors essential services. RSA’s Commission for Conciliation, Mediation and Arbitration hereinafter after referred to as (the “CCMA”)14 runs an electronic system of case management by which cases are screened and assigned commissioners whereas Zimbabwe and Botswana still rely on manual systems often inefficiently managed especially when it comes to allocating matters to ADR interventionists.15 In Zimbabwe the challenge of resources is acute often the Labour Officers lacking a simple photocopier and postage stamps to dispense with administration of disputes. This dissertation found that Botswana and Zimbabwe lack publicly available information from which to infer the efficaciousness of ADR practices therein. Measuring client satisfaction, efficiency and cost effectiveness, enforcement and settlement has not been tackled with ease, which was different when it came to RSA. This study argues that RSA’s ADR is efficacious rated at 75% attainment of settlement of disputes, despite accusations of failing to offer disputants options and job retention at the end of ADR intervention. Botswana and Zimbabwe on the measures raised above are not yet close to achieving efficaciousness based on the above criteria. The challenges need to be addressed to ensure that in all three measures ADR affords Botswana, RSA and Zimbabwe disputants a cheaper, efficient and effective alternative to dispensing with labour disputes. This study concluded with recommendations arising from the three measures ADR Background Conditions; ADR Program Design and (3) ADR Measures could be implemented towards achieving an efficacious ADR regime for the three countries and beyond. / Mercantile Law / LL.M.

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