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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.
11

Resource conservation and optimization via process integration

Gabriel, Frederico Burjack 12 April 2006 (has links)
The process industries are characterized by the enormous use of natural resources such as raw materials, solvents, water, and utilities. Additionally, significant amounts of wastes are discharged from industrial facilities. As the world moves toward sustainable progress, that is, meeting the demand of the current generation without affecting or compromising the new generation, future process facilities must focus on resource conservation and pollution prevention. The purpose of this work is to introduce a new process integration methodology for the conservation and optimization of resources in the process industries. The work is also geared towards reducing waste discharge from the processing facilities. The optimal management of fresh resources and waste disposal requires the appropriate allocation, generation, and separation of streams and species. Material recycle/reuse/substitution, reaction alteration, and process modification are some of the main strategies employed to conserve resources in the process industries. The overall problem addressed in this dissertation can be stated as follows: Given is a process with a number of streams (sources) that are characterized by certain criteria (e.g., compositions of certain compounds, targeted properties) where these streams can be utilized in a number of process units (sinks) if they satisfy given constraints on flow rate, compositions, and/or properties. Additionally, interception devices may be used to adjust stream criteria. The objective is to develop targeting procedures and synthesis tools for the identification of minimum usage of fresh resources, minimum discharge of waste, and maximum integration of process resources. The devised methodology addresses four classes of problems: • Targeting techniques using direct recycle strategies • Recycle and interception procedures for single-component systems • Recycle and interception procedures for multi-component systems • Property integration for direct recycle strategies The framework provided by this dissertation couples traditional mass integration with groundbreaking property integration techniques to target, synthesize and optimize a plant for maximal conservation of resources. In particular, this work introduces new techniques such as material recycle pinch analysis, simultaneous recycle and interception networks, and property-based allocation. Additionally, graphical, algebraic, and optimization approaches are developed and validated with case studies in order to illustrate the applicability of the devised procedures.
12

Germanium and epitaxial Ge:C devices for CMOS extension and beyond

Jamil, Mustafa 21 October 2011 (has links)
This work focuses on device design and process integration of high-performance Ge-based devices for CMOS applications and beyond. Here we addressed several key challenges towards Ge-based devices, such as, poor passivation, underperformance of nMOSFETs, and incompatibility of fragile Ge wafers for mass production. We simultaneously addressed the issues of bulk Ge and passivation for pMOSFETs, by fabricating Si-capped epitaxial Ge:C(C<0.5%) devices. Carbon improves the crystalline quality of the channel, while Si capping prevents GeOx formation, creates a quantum well for holes and thus improves mobility. Temperature-dependent characterization of these devices suggests that Si cap thickness needs to be optimized to ensure highest mobility. We developed a simple approach to grow GeO₂ by rapid thermal oxidation, which provides improved passivation, especially for nMOSFETs. The MOSCAPs with GeO₂ passivation show ~10× lower Dit (~8×10¹¹ cm⁻²eV⁻¹) than that of the HF-last devices. The Ge (111) nMOSFETs with GeO₂ passivation show ~2× enhancement in mobility (~715 cm²V⁻¹s⁻¹ at peak) and ~1.6× enhancement in drive current over control Si (100) devices. For improved n⁺/p junctions, we proposed a simple technique of rapid thermal diffusion from "spin-on-dopants" to avoid implantation damage during junction formation. These junctions show a high ION/IOFF ratio (~10⁵⁻⁶) and an ideality factor of ~1.03, indicating a low defect density, whereas, ion-implanted junctions show higher Ioff (by ~1-2 orders) and a larger ideality factor (~1.45). Diffusion-doped and GeO₂-passivated Ge(100) nMOSFETs show a high ION/IOFF ratio (~10⁴⁻⁵) , a low SS (111 mV/decade), and a high [mu]eff (679 cm²V⁻¹s⁻¹ at peak). Moreover, diffusion-doped Ge (111) nMOSFETs show even higher [mu]eff (970 cm²V⁻¹s⁻¹ at peak) that surpasses the universal Si mobility at low Eeff. For Beyond CMOS devices, we investigated Mn-doped Ge:C-on-Si (100), a novel Si-compatible ferromagnetic semiconductor. The investigation suggests that the magnetic properties of these films depend strongly on crystalline structure and Mn concentration. On a different approach, we developed LaOx/SiOx barrier for Spin-diodes that reduces contact resistance by ~10⁴, compared to Al₂O₃ controls and hence is more conducive for spin injection. These ferromagnetic materials and devices can potentially be useful for novel spintronic devices. / text
13

Optimising the role of facilities management (FM) in the property development process (DP) : the development of an FM-DP integration framework

Masuri, Mohd Rayme Anang January 2015 (has links)
This thesis is a manifestation of efforts to integrate FM into the development process through a greater involvement of Facilities Managers in the property development industry. It also presents an original contribution to knowledge in a form of a validated best practice, which is identified as the facilities management-development process (FM-DP) integration framework. The framework potentially serves as a guide to Facilities Managers and other professionals in various organisations in the property development industry to optimise the value of Facilities Management (FM) in the development project and to achieve sustainable development. The study was conducted as an exploratory sequential mixed methods design in order to identify the issues that limit Facilities Managers from being involved in the property development industry, when they are known to be an appropriate professional to optimise the value of FM in the development process. Qualitative approach has been used as a core component of this research in order to obtain confirmation of the critical issues obtained from the literature review. To develop the framework, a survey questionnaire was used followed by relevant statistical procedure and analysis. To ensure validation, a member-checking approach was implemented through focus group interview. The validated framework reveals that there are 52 best practices to be considered by Facilities Managers or other professionals in the property development industry to optimise the role of FM in the development process for sustainable development. In addition, the framework discovers that best practices are required in all stages of the development process. Nevertheless, Stage 4: Technical Design is crucial, as it requires most of the best practices that drive the integration of FM into the development process. The framework demonstrates a ‘killing two birds with one stone’ strategy: (i) exploiting the framework is expected to increase the profile of FM among other professionals, (ii) encouraging a greater involvement of Facilities Managers in the property development industry, which (iii) leads the project to a sustainable development agenda.
14

Design and optimization of energy systems with effective carbon control

Gharaie, Mona January 2013 (has links)
Environmental concerns about the effect of greenhouse gases have led governments to regulate industrial CO2 emissions, including through emissions caps, trading and penalties, thus creating economic incentives to reduce CO2 emissions. This research focuses on strategies to reduce CO2 emissions from energy systems in the context of the process industries. In the process industries, energy systems consume fuel to generate steam and power for site process units. Improving energy efficiency can reduce costs of energy generation and use, as well as CO2 emissions. This research develops an integrated design and optimisation methodology for energy systems, allowing effective capture and control of carbon dioxide emissions. The first focus of this study is to develop a systematic approach to evaluate combinatorial strategies for reducing CO2 emissions, based on a techno-economic analysis. A conceptual design procedure with hierarchical decision-making is introduced to combine CO2 emissions reduction strategies, accounting for interactions between site components, including the heat exchanger network and utility system. CO2 emissions reduction options considered in development of this procedure include process integration techniques for improving the energy efficiency of the site and fuel switching. The proposed approach considers trade-offs between the economy of energy retrofit and CO2 emissions penalties. Opportunity for reducing the CO2 penalty is included in the economic evaluation of the combined emissions reduction strategies. A mathematical model for simultaneous optimization of emissions reduction strategies is developed. In addition to emissions reduction strategies, options for trading CO2 allowances are considered in the model. The proposed mathematical method applies Mixed Integer Non Linear Programming (MINLP) optimization, which employs a superstructure of the strategies for CO2 reduction. The proposed mathematical model relates the selected options to their operating and capital costs and to their associated CO2 emissions, allowing the optimizer to search for the optimal combination of emissions reduction strategies. While the reduction in CO2 emissions through process integration techniques is based on the existing configuration of a site and the associated structural limitations, integration of Carbon Capture and Storage (CCS) technologies can provide greater mitigation of CO2 emissions from a site. However, important challenges of implementing CCS in the process industries are the energetic and economic impact of the CCS plant on the integrated site. In the second part of this study, these energy-economic issues are explored. The CCS technologies addressed in this thesis include post- and pre-combustion CO2 capture techniques. Simulation of each capture technique is carried out in process simulation software to characterize the energy performance of the CO2 capture plant. Sensitivity analyses are carried out for key parameters of the CO2 capture plant. The relationship between these key parameters and the energy balance of the capture plant is represented using a simple energy performance model for the CO2 capture plant. This model allows the integration of the CO2 capture plant with the site utility system to be explored. Interactions between the utility system and CO2 capture plant are considered. The site utility system, together with the CO2 capture plant, is optimized for minimum operating cost. The proposed procedures are illustrated by application to a case study of a medium-scale oil refinery. The results illustrate that to reduce CO2 emissions, heat integration, utility system optimization and fuel switching provide more cost-effective solutions than integrating CCS technologies. The mathematical model allows more cost-effective solutions to be identified than using sequential, conceptual methods, but the value of the conceptual method for developing insights is also illustrated. The results demonstrate that, depending on the potential of the site for increasing heat recovery and the type of fuel used on site, solutions that combine energy efficiency and fuel switching can provide up to 40% reduction in site CO2 emissions. Integrating a post-combustion CO2 capture plant with the site utility system can provide up to 90 mol% pure CO2 for sequestration; however, the high capital cost of the capture plant reduces the economic performance of the integrated site. The high heat demand of post-combustion CO2 capture for solvent regeneration increases the fuel consumption of the site and its utility system, which in turn reduces the recovery of CO2. The results reveal that pre-combustion CO2 capture can provide opportunities for heat and power generation to improve the techno-economic performance of the overall integrated site.
15

Studies in process integration of energy and environmental systems

Autret, Erwan 10 July 2009 (has links)
This thesis discusses topics in the field of process engineering that have received much attention over the past twenty years, process integration and optimization of energy and environmental systems. It emphasizes the applications of three commercial software tools for process integration, ADVENT, HEXTRAN and SlTPERTARGET, that are readily available to academic users at low costs. Specifically, Chapter 1 presents an overview of the basic concepts used in process integration of energy systems. Chapter 2 compares the use of single and dual temperature-of-approach methods to synthesize energy-optimum and minimum-cost, heat-exchanger networks (HENs), and shows how to implement them using three software tools. Chapters 3 and 4 demonstrate how to optimize the energy recovery in petroleum refinery distillation systems via process integration. Chapter 3 presents an extension to a case study of heat integration of a vacuum distillation system. Chapter 4 describes the detailed synthesis, retrofit and optimization of HENs for a system of atmospheric and vacuum distillation towers, and it represents the first process integration and optimization study of a complex process in petroleum refineries using all three commercial software tools. Chapter 5 presents, through four progressive tutorial examples, a recent conceptual method developed in the field of process integration of environmental systems applied to wastewater minimization and to the design of distributed effluent treatment systems. / Master of Science
16

Limited upstream dyadic integration of the Supplier Relationship Management process within the construction equipment industry in Sweden : An analysis of the sub-process integration from the manufacturer’s perspective

Fakhrai Rad, Fakhreddin, Lebel, Benoit, Wu, Bingzhou January 2015 (has links)
The supplier relationship manager is one of the eight business processes of Supply chain management. There have been many researches carried out about the supply chain processes integration. However, a lack of theory has been noticed on the integration of the supplier relationship management process and no research has coped with a case study of the integration of this process between the manufacturer and its first upstream tier. The lack is also consequent when studying the obstacles to the supplier relationship management integration in Swedish construction equipment companies.
17

Integrating biomass gasification with electric arc furnace steel making / Integrering av biomassaförgasning med ljusbågsugn

Andersson, Filippa January 2023 (has links)
Utsläppen av växthusgaser ökar över hela världen och nya tekniker används för att minska utsläppen. 7% av utsläppen kommer från stålsektorn. 25% av världens stålproduktion görs via återvinningstekniken ljusbågsugn. Genom återvinningsprocessen släpps det ut 500kg CO2 per ton producerat flytande stål. En möjlighet att sänka dessa direkta utsläppär att koppla ljusbågsugnsprocessen med biomassa förgasnings och koldioxidavskiljning. Den föreslagna lösningen i denna avhandling är att utnyttja avgaserna från stålsmältningen i förgasningsprocessen och skapa värdefulla produkter. Projektet utvärderar den tekniska genomförbarheten i form av energieffektivitet och kolutnyttjande. Den föreslagna processen simulerades med Aspen Plus. Ett problem med ljusbågsugnens avgaser är fluktuationen i sammansättningen. Tre fall avavgassammansättning undersöktes. Fall 1 var den genomsnittliga avgassammansättningen, medan fall 2 och 3 var extrema med högt CO- respektive CO2-innehåll. Resultatet visade att syntetsgassammansättningen starkt beror på förgasningsmedlet. I samtliga fall ökade energieffektiviteten och de direkta utsläppen minskade, jämfört med nuvarande process. Fall 1 visade generellt högst effektivitet och kolutnyttjande, medan det CO2 rika fallet (fall 3) hade lägst. Ett kontinuerligt flöde av förgasningsmedel krävs för att driva förgasningsprocessen. Eftersom ljusbågsugn är en satsvis process, sker luftförgasning när avgaser inte är tillgängliga. Det önskade resultatet av luftförgasning är att producera syntetsgas som liknar avgasförgasningens syntesgas. Resultaten visade att luftinfiltration i avgaser är gynnsamt för mer liknande syntesgas . / Greenhouse gas emissions are increasing worldwide, and new techniques are being adopted to suppress the emissions. The steel sector is responsible for 7% of the emissions. 25% ofthe world’s steel production is made through the recycling technique EAF. Throughout the recycling process, 500 kg CO2 gets emitted per ton of liquid steel produced. An opportunity to lower these direct emissions is to couple the EAF process to biomass gasification and CO2 utilisation process. The proposed solution in this thesis is to utilise the off-gases in the gasification process and create high-valuable products. The project evaluates the technical feasibility via energy efficiency and carbon utilisation. The proposed process was simulated using Aspen Plus. A problem with the off-gases from EAF gasification is the fluctuation in composition. Three cases of off-gas composition were therefore investigated. Case 1 was the average off-gas composition, while cases 2 and 3 were extreme with high CO and CO2 content, respectively. The result showed that the syngas composition strongly depends on the gasifying agent. In all cases, the energy efficiency increased, and the direct emissions decreased. Case 1 generally showed the highest efficiency and carbon utilisation, while the CO2 heavily case (case 3) had the lowest. A continuous flow of gasifying agents is required to run the gasification process. Since EAF is a batch process, air gasification runs when off-gases are unavailable. The desired outcome of air gasification is to produce syngas similar to off-gas gasification. The results showed that air infiltration in off-gases is favourable for more similar syngas composition.
18

Process Window Challenges in Advanced Manufacturing: New Materials and Integration Solutions

Fox, Robert, Augur, Rod, Child, Craig, Zaleski, Mark 22 July 2016 (has links) (PDF)
With the continued progression of Moore’s law into the sub-14nm technology nodes, interconnect RC and power dissipation scaling play an increasingly important role in overall product performance. As critical dimensions in the mainstream Cu/ULK interconnect system shrink below 30nm, corresponding increases in relative process variation and decreases in overall process window mandate increasingly complex integrated solutions. Traditional metallization processes, e.g. PVD barrier and seed layers, no longer scale for all layout configurations as they reach physical and geometric limitations. Interactions between design, OPC, and patterning also play more and more critical roles with respect to reliability and yield in volume manufacturing; stated simply, scaling is no longer “business as usual”. Restricted design layouts, prescriptive design rules, novel materials, and holistic integration solutions each therefore become necessary to maximize available process windows, thus enabling new generations of cost-competitive products in the marketplace.
19

CO<sub>2</sub> Capture With MEA: Integrating the Absorption Process and Steam Cycle of an Existing Coal-Fired Power Plant

Alie, Colin January 2004 (has links)
In Canada, coal-fired power plants are the largest anthropogenic point sources of atmospheric CO<sub>2</sub>. The most promising near-term strategy for mitigating CO<sub>2</sub> emissions from these facilities is the post-combustion capture of CO<sub>2</sub> using MEA (monoethanolamine) with subsequent geologic sequestration. While MEA absorption of CO<sub>2</sub> from coal-derived flue gases on the scale proposed above is technologically feasible, MEA absorption is an energy intensive process and especially requires large quantities of low-pressure steam. It is the magnitude of the cost of providing this supplemental energy that is currently inhibiting the deployment of CO<sub>2</sub> capture with MEA absorption as means of combatting global warming. The steam cycle of a power plant ejects large quantities of low-quality heat to the surroundings. Traditionally, this waste has had no economic value. However, at different times and in different places, it has been recognized that the diversion of lower quality streams could be beneficial, for example, as an energy carrier for district heating systems. In a similar vein, using the waste heat from the power plant steam cycle to satisfy the heat requirements of a proposed CO<sub>2</sub> capture plant would reduce the required outlay for supplemental utilities; the economic barrier to MEA absorption could be removed. In this thesis, state-of-the-art process simulation tools are used to model coal combustion, steam cycle, and MEA absorption processes. These disparate models are then combined to create a model of a coal-fired power plant with integrated CO<sub>2</sub> capture. A sensitivity analysis on the integrated model is performed to ascertain the process variables which most strongly influence the CO<sub>2</sub> energy penalty. From the simulation results with this integrated model, it is clear that there is a substantial thermodynamic advantage to diverting low-pressure steam from the steam cycle for use in the CO<sub>2</sub> capture plant. During the course of the investigation, methodologies for using Aspen Plus?? to predict column pressure profiles and for converging the MEA absorption process flowsheet were developed and are herein presented.
20

[en] IT STRATEGIES FOR THE ELECTRONIC INTEGRATION OF INFORMATION: A STUDY OF THE STATE OF THE ART AND THE PRACTICE / [pt] ESTRATÉGIAS DE TI PARA A INTEGRAÇÃO ELETRÔNICA DA INFORMAÇÃO: UM ESTUDO SOBRE O ESTADO DA ARTE E DA PRÁTICA

DANIEL VALENTE SERMAN 03 March 2008 (has links)
[pt] A informação passou a ser vista ao longo do tempo como um insumo importante para a tomada de decisão e para a obtenção de vantagens competitivas pelas empresas. A tecnologia passou a fazer parte do cotidiano das empresas para melhor administrá-la e disseminá-la. Entretanto, nem sempre as organizações adotaram esse caminho de forma planejada. Percebe-se uma confusão no uso de conceitos e de soluções em TI, que se estende para o tema da integração eletrônica da informação. O trabalho consistiu em uma revisão da literatura sobre a integração de sistemas e de dados, verificando-se os conceitos mais comuns, as soluções mais utilizadas e as promessas encontradas. Além disso, realizou-se uma pesquisa de campo, na qual gestores expuseram em entrevistas qualitativas o que acontece na prática sobre o assunto, aludindo a benefícios, problemas e requisitos para o desenvolvimento e adoção de soluções de integração. / [en] Organizations began to see information like an important component for decision making and obtaining above average profits, when well used. Computational tools and communication technologies became common on the quotidian of these organizations. However, those tools and technologies weren`t always adopted through the right way. We notice confusion on the use of concepts and the adoption of solutions on IT and that problem extends to information integration. This work consisted on an intense review of the literature about systems and data integration, verifying most common concepts, most utilized solutions and promises about them. Besides, a field research was realized, which manages showed on qualitative interviews what actually happens about this subject, referring to benefits, problems and requisites for the development and adoption of integration solutions.

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