• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 6
  • 3
  • 1
  • Tagged with
  • 19
  • 19
  • 8
  • 8
  • 7
  • 7
  • 6
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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

PDM based Lifecycle Analysis – A Case Study

Gerhard, Detlef, Rahmani, Touba 25 September 2017 (has links) (PDF)
To facilitate collaborative design in vocational education institutions, we have conducted a project to establish a nationwide PDM platform for four different schools spread all over the country. The particular aim of a follow up project introduced in this paper is to sensitize the participating students to sustainable design and lifecycle assessment (LCA) and provide them with hands-on tools through the PDM platform to accomplish these tasks. As a collaborative case study project, a cordless drill driver was chosen to be re-designed with respect to Ecodesign aspects. Since LCA is truly a holistic task, we focused on the ecological aspects of material and production stage. Distribution, usage and end-of-life stages were left out as well as economic and social aspects. The drill driver was divided into housing, drill chuck, gear and power unit. Each component was assigned to one of the schools and had to be designed with respect to reduced environmental impacts. Since different CAD systems are used the decision to provide the needed tools and environmental information within the PDM platform rather than CAD environment was easy. Some of the PDM systems on the market do also provide lifecycle analysis modules but it is rather a black box approach than a transparent data and reporting source. Because LCA heavily relies on the method itself and the way analysis is conducted we decided to develop our own tools. Therefore, a new, adapted interface was developed using open source business intelligence software called Pentaho to facilitate on the fly reporting and analytics of the work in progress by the users. Furthermore, the Ecoinvent database was connected to the PDM system to provide required information on carbon footprint and cumulated energy demand. The paper discusses strength and weaknesses of tools and methods with respect to the introduced case study and gives an outlook on ontology representation for the data model for better analysis capabilities.
2

Using CO2 emission quantities in bridge lifecycle analysis

伊藤, 義人, Itoh, Yoshito, 北川, 徹哉, Kitagawa, Tetsuya 21 December 2002 (has links)
No description available.
3

Lifecycle Analysis of Bridges Considering Longevity of Bridge and Severe Earthquakes

伊藤, 義人, Itoh, Yoshito, 坪内, 佐織, Tsubouchi, Saori, Wada, M 08 1900 (has links)
No description available.
4

PDM based Lifecycle Analysis – A Case Study

Gerhard, Detlef, Rahmani, Touba 25 September 2017 (has links)
To facilitate collaborative design in vocational education institutions, we have conducted a project to establish a nationwide PDM platform for four different schools spread all over the country. The particular aim of a follow up project introduced in this paper is to sensitize the participating students to sustainable design and lifecycle assessment (LCA) and provide them with hands-on tools through the PDM platform to accomplish these tasks. As a collaborative case study project, a cordless drill driver was chosen to be re-designed with respect to Ecodesign aspects. Since LCA is truly a holistic task, we focused on the ecological aspects of material and production stage. Distribution, usage and end-of-life stages were left out as well as economic and social aspects. The drill driver was divided into housing, drill chuck, gear and power unit. Each component was assigned to one of the schools and had to be designed with respect to reduced environmental impacts. Since different CAD systems are used the decision to provide the needed tools and environmental information within the PDM platform rather than CAD environment was easy. Some of the PDM systems on the market do also provide lifecycle analysis modules but it is rather a black box approach than a transparent data and reporting source. Because LCA heavily relies on the method itself and the way analysis is conducted we decided to develop our own tools. Therefore, a new, adapted interface was developed using open source business intelligence software called Pentaho to facilitate on the fly reporting and analytics of the work in progress by the users. Furthermore, the Ecoinvent database was connected to the PDM system to provide required information on carbon footprint and cumulated energy demand. The paper discusses strength and weaknesses of tools and methods with respect to the introduced case study and gives an outlook on ontology representation for the data model for better analysis capabilities.
5

Avoided Water Cost of Electricity Generation for Solar PV and Wind Technologies in Southern California

Cohen, Matthew 01 August 2014 (has links)
The objective of this thesis is to provide a foundation for evaluating the water costs associated with electricity production to calculate the avoided water cost of energy for solar PV and wind technologies relative to coal, natural gas, nuclear, geothermal, concentrated solar thermal, and biomass. Water consumption is estimated for energy production (fuel extraction and preparation) and electricity generation (power plant operation) using the best available information from published articles. The quantity of water consumed for electricity production is monetized for a Southern California case study based on the water rates of Metropolitan Water District of Southern California (MET), which is the largest wholesale supplier of surface water in the United States. Water withdrawals are addressed but not included in the monetization of water consumption. Case studies of specific power plant’s water costs are used for comparison and demonstrate variation in water costs due to variations in water consumption. Water costs are estimated in terms of water cost ($) per unit energy generated (MWh). Since solar PV and wind energy are shown to have negligible water consumption relative to the other technologies, the water costs for each of the other electrical generation methods are equivalent to the water savings potential of solar PV and wind generated electricity. Compared to other evaluated electricity sources that could provide electricity to Southern California, solar PV and wind energy can save water worth $0.76/MWh for natural gas combined-cycle plants, $0.94/MWh for geothermal power plants, $1.01/MWh for biomass power plants, between $1.14 and $1.82 per MWh for concentrated solar thermal plants, $1.43/MWh for nuclear power plants, and $1.49/MWh for coal power plants. Results indicate that there are three processes that use substantial amounts of water: fuel extraction (for coal, natural gas, and nuclear), thermoelectric cooling of power plants and emissions controls such as carbon capture and sequestration. Carbon capture and sequestration are estimated to almost double the water consumption costs of coal and natural gas power plants. Of the evaluated technologies, only solar PV and wind do not require any of those three steps. Solar PV and wind energy can thus save the greatest value of water when displacing power plants that utilize (or may someday be required to utilize) all three of the major culprits of water consumption. Even the use of one of these processes (particularly thermoelectric cooling) results in substantial water consumption. Total water costs for each technology were normalized to the total expected electrical output of a typical capacity natural gas combined-cycle power plant to demonstrate the economies of scale of power production. Over a forty year lifespan of a typical natural gas power plant, total water consumption would result in $67 million worth of water (southern CA wholesale prices). To generate the same amount of electricity the total value of water consumption is estimated to be $83 million for geothermal plants, $89 million for biomass plants, $100 million to $160 million for concentrated solar thermal plants, $126 million for nuclear plants, and $131 million for coal power plants. The use of carbon capture and sequestration is expected to nearly double these total water costs. Compliance with environmental regulations can cause expenses much greater than water consumption. For example, mitigation costs for impingement and entrainment (a consequence of cooling water withdrawals) as well as the cost to convert to closed-loop cooling for environmental compliance can be considered costs associated with water usage. This is demonstrated by a case study about the Los Angeles Department of Water and Power regarding the elimination of once through cooling. The conversion to closed-loop cooling for the Haynes natural gas power plant is expected to cost $782 million, resulting in an estimated unit cost of $10.66/MWh. Finally, the economic benefits of the California Renewables Portfolio Standard are calculated with respect to water consumption. By holding hydroelectricity, geothermal, biomass and CST production constant and utilizing solar PV and wind to meet the 33% renewables target by 2020, a water value of $28.5 million/year can be conserved relative to meeting rising electricity demand with only natural gas combined-cycle generation. MET water rates increased 70% from 2008 to 2014. If water rates increase at the same rate over the next six years, the water savings of the Renewable Portfolio Standard would be 70% higher in 2020 dollars, equating to water savings of $48.4 million per year.
6

橋梁支承用ゴムの環境劣化特性に関する基礎的研究

伊藤, 義人, ITOH, Yoshito, 矢澤, 晃夫, YAZAWA, Akio, 佐藤, 和也, SATOH, Kazuya, 顧, 浩声, GU, Haosheng, 惣那, 幸浩, KUTSUNA, Yukihiro, 山本, 吉久, YAMAMOTO, Yoshihisa 07 1900 (has links)
No description available.
7

Costing for the Future: Exploring Cost Estimation with Unmanned Autonomous Systems

Ryan, Thomas Robert Jr. January 2015 (has links)
This thesis explores three topics in the field of cost estimation for Unmanned Autonomous Systems. First, we propose a common definition of an Unmanned Autonomous System. We accomplish this through exhausting the literature in the areas cost estimation, autonomy in its current form, and how such advanced systems might be integrated into their environment. Second, we introduce a method to estimate the cost of Unmanned Autonomous Systems utilizing existing parametric cost estimation tools: SEER–HDR, COCOMO II, COSYSMO, and two cost estimating relationships–weight and performance. This discussion is guided by focusing on how current tools attempt to account for emergent systems. We also attempt to address challenges surrounding autonomy. To address these challenges from a cost perspective, this thesis recommends modifications to parameters within COCOMO II–via the use of object-oriented function points in lieu of current methods, and COSYSMO–via the introduction of two cost drivers namely, TVED and HRI-T. Third, we conduct analysis on four current Army Unmanned Autonomous Systems in an attempt to establish early trends within existing estimates. Finally, we explore areas of further research and discuss the implications of how pursing a more adequate cost model will lead to a better understanding of this ill-defined paradigm. *This material is based upon work supported by the Naval Postgraduate School Acquisition Research Program under Grant No. N00244-15-1-0008. The views expressed in written materials or publications, and/or made by speakers, moderators, and presenters, do not necessarily reflect the official policies of the Naval Postgraduate School nor does mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government.
8

Lifecycle cost and CO2 emission comparison of conventional and rationalized bridges

Liu, Chunlu, Kim, In-Tae, Tsubouchi, Saori, Itoh, Yoshito January 2006 (has links)
No description available.
9

Ökade isoleringstjocklekars möjligheter och begränsningar / Possibilities and limitations of increased insulation thicknesses

Eriksson, Per, Rosenlund, David January 2020 (has links)
Sammanfattning Syfte: Bygg och fastighetssektorn står för en stor andel av de nationella utsläppen av växthusgaser. Studier visar att klimatpåverkan för drift och produktionsfasen är ungefär ekvivalenta. Majoriteten av produktionsfasens klimatpåverkan härstammar från materialen. Samtidigt som det behövs byggas fler bostäder behöver klimatpåverkan för denna sektor minska, för att uppnå bestämda klimatmål. För att klara av dessa utmaningar behöver isoleringsmaterial och deras påverkan belysas. Isoleringsmaterialet i en byggnad har som syfte att bibehålla värmen i inneklimatet genom att isolera mot ytterklimatet. Tjockare isoleringsskikt leder till bättre isoleringsförmåga och därmed lägre behov för uppvärmning. Dock leder ökad isoleringstjocklek till mer materialåtgång som i sin tur innebär ökad klimatpåverkan för väggkonstruktionen i sin helhet. ”Målet med studien är att klargöra hur olika tjocklekar på isoleringsmaterial av mineralull och cellulosa i byggnader påverkar miljön ur ett livscykelperspektiv. Samt att undersöka vilka marknadsandelar de ingående materialen har.” Metod: Studien har en kvantitativ ansats med fallstudie, litteraturstudie samt dokumentanalys som metod för att uppnå målet genom att besvara frågeställningarna. Resultat: Mineralull står för minst 50% av marknaden. De förnyelsebara isoleringsmaterialen har kring 2% av marknaden. Cellulosa är det populäraste isoleringsmaterialet av de förnyelsebara. Studien visar på att byggnaden kan öka isoleringen i väggar över det befintliga med cellulosa 813mm, glasull 268mm och stenull 176mm. Isolering i tak kan ökas med 938 mm cellulosa, 319 mm glasull och 214 mm stenull. Återvinning kan möjliggöra att tilläggsisoleringen kan ökas med 103–140% jämfört med hur isoleringsmaterialen avfallshanteras i dagsläget. Konsekvenser:▪ Mineralull står för en stor andel av marknaden, samtidigt som cellulosa enbart står för någon enstaka procent ▪ Vid bestämmande av isoleringstjocklek ur ett klimatperspektiv, spelar val av isoleringsmaterial och avfallshantering en betydande roll ▪ Hur stor klimatpåverkan ett isoleringsmaterial har begränsar mängden isolering som bör användas i byggnaden ▪ Klimatpåverkan för vald uppvärmningsmetod kommer påverka mängd isolering som bör användas i byggnaden Begränsningar: Denna studie är specifik för denna fallstudie. Resultatet kan ses som en fingervisning kring hur olika tjocklekar av isolering påverkar liknande byggnader. Ingen hänsyn tas till konstruktion och att minskat värmebehov leder till ändrade tekniska lösningar. / Abstract Purpose: The construction and real estate sector are responsible for a large part of the national emissions of greenhouse gases. Study’s shows that construction and the usage phase has more or less the same climate impact. In the construction phase, most of the climate impact comes from the materials. At the same time as there is needs for more residential there is also a need for this sector to reduce its climate footprint to achieve national climate goals. More knowledge about insulation materials is needed to achieve these challenges. The purpose of insulation in buildings is to keep the heat inside and protect against the outdoor climate. Thicker insulation gives a better insulation and therefor lower demand of heating. Thicker insulation leads however to increased material usage and therefor higher environmental impact. “The purpose of this study is to clarify the environmental impact of insulation thicknesses through a lifecycle analysis. Recycling and market shares of insulation materials are analyzed as well.” Method: To reach the goal, the study uses a quantitative approach with case study, literature study and document analysis as methods. Findings: Mineral wool has at least 50% of the insulation market. The renewable materials have around 2% of the market, of these percent cellulose is the dominated insulation material. The study shows that the building in the case study can increase its insulation on the walls with cellulose 813mm, glass wool 268mm, stone wool 176mm. increased roof insulation with cellulose 938mm, glass wool 319mm, stone wool 214mm. Recycling can increase the amount of added insulation by 103-140% compared to landfill and incineration alternative. Implications: ▪ Mineral wool has a significant share of the insulation market, at the same time as cellulose only have a couple percent of the market ▪ When determine insulation thickness from an environmental perspective, the insulation material and the waste treatment methods have a considerable impact. ▪ The environmental impact of an insulation material limits the amount that should be installed in the building. ▪ The environmental impact of heating method will impact the amount of insulation that should be installed in the building Limitations: The study is only applicable for its building. The results can however be used as guidance in insulation thicknesses on similar buildings. This study does not take into consideration how increased wall and roof dimensions effects structural and decreased need on the heating system.
10

Shape Memory Based Self-Powered Fluid Pump

Katzenburg, Stefan, Spanke, Nina, Langhoff, Moritz, Faller, Clemens 13 February 2024 (has links)
In the range of 25°C - 80°C (ultra-low grade heat), a large quantity of waste heat from various processes is available unused. Special alloys made of nickel and titanium, so-called Shape Memory Alloys (SMA), could be an alternative technology to Organic Rankine Cycles to make this energy usable in the low power range. The 'THEAsmart 2' research project is therefore investigating the service life and energy lifecycle of this material to test the benefits of shape memory alloys in energy recovery and the efficiency levels that can be achieved. To this end, a demonstration prototype is being built that converts thermal energy into rotary motion. The next step is to link the demonstration prototype with a conventional fluid pump to create an SMA fluid pump that is driven by the thermal energy of the fluid to be pumped. The advantage of such a pump would be that it would be energy-independent, i.e. it would be operated solely by the thermal energy of the fluid without an electrical connection. Furthermore, such a pump could contribute to energy savings if it is used in cooling circuits in which the thermal energy of the fluid is the waste product from another process. In this case, it replaces an electric pump and utilizes the 'waste product' heat. The aim of the project is to investigate how and whether coil springs made of shape memory alloy are suitable for energy recovery. This is considered via the energy lifecycle: if more energy is required to manufacture a spring than this spring can convert kinetic energy from thermal energy in its lifecycle, then its use for energy recovery does not make sense in principle. As a secondary result of this research, statements about the efficiency of shape memory alloy coil springs and statements about their service life are expected.

Page generated in 0.0644 seconds