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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

Soil-structure interaction of end-frames for high-speed railway bridges / Jord-struktur-interaktion av ändskärmar på broar för höghastighetståg

Östlund, Johan January 2016 (has links)
In this thesis, the influence of soil-structure interaction (SSI) of end-frame bridges for high-speed railways was studied. Impedance functions, representing the SSI, was calculated and analyzed. The impedance functions were applied to end-frame bridge models which were analyzed for use in HSR. A new high-speed railway link is currently being planned in Sweden by the Swedish Transport Administration (Trafikverket). \textit{Ostl\"{a}nken} is planned to run between the cities of Stockholm and Link\"{o}ping with a maximum speed limit of 320km/h. As high-speed traffic induces high dynamic impact on bridges, dynamic analysis to ensure safety and passenger comfort is needed according to Eurocode. Thus, there is a demand of dynamically safe bridges that are also cost-effective. One cost-effective bridge is the soil integrated end-frame bridge, however, there are no design advice in Eurocode today on how to take SSI into consideration. The aim of the thesis has therefore been to investigate if the influence of SSI on end-frame bridges for HSR. This thesis was executed using the frequency domain approach to solve dynamic problems in finite element software. Furthermore, impedance functions have been obtained representing the SSI. Impedance functions take dynamic stiffness and dynamic damping into consideration where the damping consists of two parts: material damping and radiation damping due to energy dissipation in the form of elastic waves. To limit the model size, an absorbing region (AR) was used to mitigate waves originating from the source. The accuracy of impedance functions is dependent on several parameters and demands a great computational capacity to reach, mostly governed by the radiation condition. A parameter study of impedance functions was conducted, including parameters such as geometry, modulus of soil and detail levels. The impedance functions were then attached to bridge models on which trains modelled as moving point loads were applied. Envelopes of the acceleration and displacements have been presented and analyzed. Shear strain checks were made in order to verify the assumption of linear-elastic material behavior of the embankment. By using SSI in form of impedance functions attached to bridge models, numerical results show a great reduction of vibrations in models. The study suggests that a large end-frame, either long or high or both, may reduce acceleration as well as displacements. A stiffer embankment material may further reduce vibrations. Shear strain checks confirm that the assumption of linear-elastic soil behavior was true. / I det här exjobbet har påverkan av jord-struktur interaktion (soil-structure interaction - SSI) av ändskärmsbroar för höghastighetsbana blivit studerat. Impedansfunktioner som representerar SSI har beräknats och analyserats. Impdansfunktionerna har sedan applicerats på bromodeller och analyserats för höghastighetstrafik. Sveriges första höghastighetsbana håller just nu på att planeras av Trafikverket. Ostlänken kommer att bli den första delen och är planerad att gå från Stockholm till Linköping med en högsta hastighet av 320 km/h. Då höghastighetstrafik introducerar stor dynamisk på verkan på broar behövs dynamisk analys genomföras enligt Eurocode för att kunna säkerställa broarnas säkerhet och komfortkrav. Därför finns idag ett behov av dynamiskt säkra broar som också är kostnadseffektiva. En typ av kostnadseffektiv bro är den med jord integrerade ändskärmsbron. I dagens Eurocode finns dock inga konstruktionsråd vad gäller jord-struktur interaktion av ändskärmarna. Målet med detta examensarbete har därför varit att undersöka påverkan av SSI och besluta huruvida användandet av ändskärmsbron på höghastighetsbanor är legitimerat, eller om den ska undvikas. Det här examensarbetet har utgått från att lösa dynamiska problem i frekvensdomänen med hjälp av FEM. Impedansfunktioner som representerar jord-struktur interaktionen har tagits fram. Impedansfunktioner tar dels hänsyn till dynamisk styvhet och dels dynamisk dämpning. Den dynamiska dämpningen består av två delar; den första är materialdämpning och den andra är vågdämpning där energi dissiperar i vågform. För att begränsa FE modellens storlek har en absorbing region tillämpats för att absorbera vågorna vid randen. Impedansfunktionernas konvergens beror på flertalet parametrar och kräver en hög datakapacitet för att fås, mestadels beroende av radiatorvillkoret. En parameterstudie utfördes för att kunna analysera sensitiviteten hos impedansfunktionerna. Vidare applicerades dessa impedansfunktioner på skal- och balk-bromodeller på vilka HSLM laster påfördes. Skjuvtöjningskontroller gjordes för att verifiera att antagandet om linjärelastiskt materialbeteende var korrekt. Genom att ta hänsyn till SSI i form av impedansfunktioner tyder numeriska resultat på att vibrationer kan reduceras i hög grad. Envelopper visar att en stor ändskärm, antingen lång, hög eller bådadera, kan reducera accelerationer liksom förskjutningar. En styvare bank kan ytterligare reducera vibrationer.
12

Biologia reprodutiva e presença de cromossomo B em Astyanax scabripinnis (Teleostei: Characidae)

Cornelio, Diana 08 February 2013 (has links)
Made available in DSpace on 2017-07-21T19:59:59Z (GMT). No. of bitstreams: 1 Diana Cornelio.pdf: 3420425 bytes, checksum: ff1f9eef75ccbe98d2e754cd2215c5c5 (MD5) Previous issue date: 2013-02-08 / Fundação de Amparo a Pesquisa do Estado de São Paulo / Astyanax scabripinnis is a species found in the neotropics, this species forms demes isolated populations in headwater streams. It is taxonomically unresolved, but is presented as an interesting model to study the presence of chromosomal B. The occurrence of these chromosomes in A. scabripinnis may be associated with various environmental factors and population, although little savvy about maintaining parasitic or possible heterotic effects of these chromosomes. The reproductive biology related to the presence of B chromosomes in A. scabripinnis never been addressed. Thus, the object of this study was to investigate whether aspects of the reproductive process, fundamental to the adaptive value may be related to the presence of B chromosomes in A. scabripinnis. Samples were collected quarterly between the years 2012 and 2013 in Campos do Jordao, Sao Paulo, Brazil (22 ° 40 '49.5 "S, 45 ° 23` 31.9 "W) at Stream Farm Lavrinha basin of the Paraíba do Sul. The gonads were classified macroscopically and microscopically second stages of development. Settled seasonally sex ratio of the population in the different samples. We calculated the gonadosomatic ratio (GSR) and the relationship hepatossomática (RHS) separately for females with and without chromosome B. The presence of B chromosomes was confirmed by classical cytogenetic and molecular with the use of chromosome specific probe B constructed by chromosome microdissection and amplification Degenerated Oligonucleotids Primers (DOP-PCR) and subsequent in situ hybridization (FISH). Geometric morphometric analysis were performed separately for males and females with and without the presence of chromosomes B. The results indicate that the sex ratio varied seasonally having an increased number of males compared to females. Hermaphrodite individuals were found at a frequency of 7.7%. The reproductive period is characterized by an atypical reproductive peak during the winter period, beyond the period observed pattern from the spring in September. The presence of B chromosomes has been linked to possible reproductive strategies in different populations studied, especially in relation to energy intake and stages of gonadal development. There morphometric differences both between individuals female and male subjects with and without chromosome B. / Astyanax scabripinnis é uma espécie encontrada na Região Neotropical, essa espécie forma demes populacionais isolados em cabeceiras de riachos. Ela é taxonomicamente mal resolvida, mas se apresenta como interessante modelo para o estudo da presença de cromossomos B. A ocorrência desses cromossomos em A. scabripinnis pode estar associada a diversos fatores ambientais e populacionais, embora seja pouco esclarecido sobre a manutenção parasítica ou possíveis efeitos heteróticos desses cromossomos. A biologia reprodutiva relacionada à presença de cromossomo B em A. scabripinnis nunca foi abordada. Assim, foi objeto deste trabalho investigar se aspectos do processo reprodutivo, fundamental para o valor adaptativo, podem estar relacionados à presença de cromossomos B em A. scabripinnis. As coletas foram realizadas trimestralmente entre os anos de 2012 e 2013 na região de Campos do Jordão, São Paulo, Brasil (22°40`49,5”S, 45°23`31,9” W), no Córrego da Fazenda Lavrinha, bacia do rio Paraíba do Sul. As gônadas foram classificadas macro e microscopicamente segundo estádios de desenvolvimento. Estabeleceu-se sazonalmente a proporção sexual da população nas diferentes amostragens. Foi calculada a relação gonadossomática (RGS) e a relação hepatossomática (RHS) separadamente para fêmeas com e sem cromossomo B. A presença de cromossomos B foi confirmada por meio da citogenética clássica e molecular com o emprego de sonda específica do cromossomo B construída por microdissecção cromossômica e amplificação por Degenerated Oligonucleotids Primers (DOP-PCR) e posterior hibridação fluorescente in situ (FISH). Análises de morfometria geométrica foram realizadas separadamente para fêmeas e machos com e sem a presença de cromossomos B. Os resultados indicam que a proporção sexual variou sazonalmente havendo um aumento do número dos machos em relação às fêmeas. Foram encontrados indivíduos hermafroditas na frequência de 7,7%. O período reprodutivo é caracterizado por um pico de reprodução atípico no período do inverno, além do período padrão observado a partir da primavera no mês de setembro. A presença de cromossomos B foi relacionada a possíveis estratégias reprodutivas distintas na população estudada, especialmente em relação ao aporte energético e estádios de desenvolvimento gonadal. Há diferenças morfométrica tanto entre indivíduos fêmeas e machos como entre indivíduos com e sem cromossomo B.
13

Soil-Structure Interaction of Pile Groups for High-Speed Railway Bridges

Strand, Tommy, Severin, Johannes January 2018 (has links)
No description available.
14

Diagnosis of health service residual management generated in the municipal district of Inhapim – MG / DIAGNÓSTICO DA GESTÃO DE RESÍDUOS DE SERVIÇO DE SAÚDE GERADOS NO MUNICÍPIO DE INHAPIM – MG

Danielly Negrão de Oliveira Guassú 31 May 2007 (has links)
lt;p align="justify"gt;The Health Service Residuals (HSR) are the ones generated in a facility related to human or animal health. They represent 1% of the total of solid residuals and the inadequate manipulation is a source of risk for human health and the environment. Small-sized municipal districts also suffer from the problem of residuals and the greatest challenge is serving the legislation. The aim of this work is evaluating the HSR management and proposing low cost measures for its implementation and operation. It was a qualiquantitative approach, through the application of checklist, semi-structure and structured interviews, and a photographic record. Analyzing the classification, segregation, conditioning, identification, storing and transportation steps, not all the institutions attended the legal requirements. The municipal district has assumed that the responsibility of external transportation and final disposition didn’t attend the required technical specifications. The legal responsibility is from the generator source. It was perceived the lack of knowledge from professionals about HSR and the limitations in the use of individual protective equipment. It can be concluded that it is possible to attend the RDC 306/04 legislation highlighting low cost measures, in the focus on integrated management of shared residuals and responsibilities, and that these proposed measures can be applicable to the reality of other small-sized municipal districts.lt;/pgt; / lt;p align="justify"gt;Os Resíduos de Serviços de Saúde – RSS são aqueles gerados em estabelecimento relacionados à saúde humana e animal e mesmo representando apenas 1% do total de resíduos sólidos no município, o seu manejo inadequado representa grande risco para o meio ambiente. Nesse particular, os municípios de pequeno porte, apesar de produzirem pequena quantidade de RSS, enfrentam sérias dificuldades para gerir esses resíduos, considerando-se as limitações técnicas e financeiras para atender às legislações vigentes. O objetivo deste trabalho foi avaliar a percepção da gestão de RSS na cidade de Inhapim, Estado de Minas Gerais, e propor medidas de baixo custo para a operação dos serviços em todas as suas etapas, conforme preconiza a Resolução Deliberativa Colegiada (RDC) 306/04. Para isso, foi realizado o diagnóstico de percepção qualiquantitativo dos RSS gerados nos estabelecimentos de saúde localizados no município. Foram aplicados questionários (entrevistas estruturadas e semi-estruturadas) a gestores e servidores dos estabelecimentos de saúde, além de visitas in loco a todos os estabelecimentos de saúde e registro fotográfico. Foi analisada a gestão dos RSS em todas as suas etapas (classificação, segregação, acondicionamento, identificação, armazenamento e transporte) e chegou-se à conclusão de que os estabelecimentos de saúde de Inhapim não atenderam às exigências preconizadas pela RDC 306/04. Apesarda responsabilidade legal pela gestão dos RSS ser do gerador, o município de Inhapim tem assumido a responsabilidade do transporte externo e disposição final desses resíduos, mesmo dos estabelecimentos privados. De forma geral, conclui-se que há um desconhecimento dos gestores e servidores dos estabelecimentos de saúde sobre RSS e limitações no uso de equipamentos de proteção individual. Acredita-se que é possível atender à legislação RDC 306/04, valorizando medidas de baixo custo, dentro da ótica da gestão integrada de resíduos e responsabilidades compartilhadas, e que podem ser aplicáveis à realidade de outros municípios de pequeno porte.lt;/pgt;
15

Automatizace rozvodny VN s využitím řídicího systému COM600 a standardu IEC61850 / Medium voltage substation automation using control system COM600 and standard IEC61850

Havelka, Tomáš January 2016 (has links)
This work deals with problematic of standard IEC61850, mainly with chapter IEC 61850-9-2 LE which is commonly known as Process bus communication. There are described advanced tools of the control system COM600 with detail description of their configuration in this work. It also deals with configuration of IEC 61850-9-2 LE with Relion family protection relays and its implementation to the control system COM600. The main aim of this work is focused on configuration of IEC 61850-9-2 standard with protection relays, configuration and detail description of COM600 advanced tools, description of Logic processor, further custom design and appliaction configuration global reset of Logic procesor in control system COM600.
16

Improving Soil Moisture Assessment of Turfgrass Systems Utilizing Field Radiometry

Roberson, Travis L. 31 January 2019 (has links)
The need for water conservation continues to increase as global freshwater resources dwindle. In response, many golf course superintendents are implementing new methods and tools to become more frugal with their water applications. For example, scheduling irrigation using time-domain reflectometer (TDR) soil moisture sensors can decrease water usage. Still, TDR measurements are time-consuming and only cover small scales, leading to many locations being unsampled. Remotely sensed data such as the normalized difference vegetation index (NDVI) offer the potential of estimating moisture stress across larger scales; however, NDVI measurements are influenced by numerous stressors beyond moisture availability, thus limiting its reliability for irrigation decisions. An alternative vegetation index, the water band index (WBI), is primarily influenced by water absorption within a narrow spectral range of near-infrared light. Previous research has established strong relationships between moisture stress of creeping bentgrass (CBG) grown on sand-based root zones, a typical scenario for golf course putting greens. However, this relationship characterizes only a small portion of total acreage across golf courses, which limits widespread adoption. In our research, '007' CBG and 'Latitude 36'hybrid bermudagrass (HBG) were grown on three soil textures, USGA 90:10 sand (S), sand loam (SL) and clay (C), arranged in a 2 x 3 factorial design, randomized within six individual dry-down cycles serving as replications. Canopy reflectance and volumetric water content (VWC) data were collected hourly between 0700 and 1900 hr using a hyperspectral radiometer and an embedded soil moisture sensor, until complete turf necrosis. The WBI had the strongest relationship to VWC (r = 0.62) and visual estimations of wilt (r = -0.91) compared to the green-to-red ratio index (GRI) or NDVI. Parameters associated with non-linear regression were analyzed to compare grasses, soils, indices, and their interactions. The WBI and GRI compared favorably with each other and indicated significant moisture stress approximately 28 hr earlier than NDVI (P = 0.0010). WBI and GRI respectively predicted moisture stress 12 to 9 hr before visual estimation of 50% wilt, whereas NDVI provided 2 hr of prediction time (P = 0.0317). When considering the time to significant moisture stress, the HBG lasted 28 hr longer than CBG, while S lasted 42 hr longer than either SL and C (P ≤ 0.0011). Nonlinear regression analysis showed that WBI and GRI can be useful for predicting moisture stress of CBG and HBG grown on three diverse soils in a highly controlled environment. Our results provide substantial evidence and direction for future research investigating how WBI and GRI can expedite moisture stress assessment and prediction on a large-acreage basis. / Master of Science in Life Sciences / Managed turfgrasses provide several benefits including filtering pollutants, cooling their surroundings, generating oxygen, preventing erosion, serving as recreational surfaces, and increasing landscape aesthetics. Intensively managed turfgrass systems, such as on golf courses and sports fields, require more inputs to maintain acceptable conditions. Freshwater use is often excessive on intensively managed turfgrasses to maintain proper plant growth. Drought conditions often limit water availability, especially in regions with limited rainfall. Turf managers tend to over-apply water across large acreage when few localized areas begin to show symptoms of drought. Additionally, turf managers sometimes wrongly identify stressed areas from other factors as ones being moisture-deprived. Advancements such as the use of soil moisture meters have simplified irrigation decisions as an aid to visual inspections for drought stress. While this method enhances detection accuracy, it still provides no solution to increase efficiency. Expanding our current knowledge of turfgrass canopy light reflectance for rapid moisture stress identification can potentially save both time and water resources. The objective of this research was to enhance our ability to identify and predict moisture stress of creeping bentgrass (CBG) and hybrid bermudagrass (HBG) canopies integrated into varying soil textures (USGA 90:10 sand (S), sand loam (SL) and Clay (C)) using light reflectance measurements. Dry-down cycles were conducted under greenhouses conditions collecting soil moisture and light reflectance data every hour from 7 am to 7 pm after saturating and withholding water from established plugs. Moisture stress was most accurately estimated over time using two vegetation indices, the water band index (WBI) and green-to-red ratio index (GRI), with approximately ninety percent accuracy to visible wilt stress. The WBI and GRI predicted moisture stress of CBG in all soil types and HBG in SL and C approximately 14 hours before the grasses reached 50% wilt. While light reflectance varies on exposed soils, our research shows that underlying soils do not interfere with measurements across typical turfgrass stands. This research provides a foundation for future research implementing rapid, aerial measurements of moisture stressed turfgrasses on a broad application of CBG and HBG on constructed or native soils.
17

高速鐵路對土地使用之短期影響分析─台灣之實證研究 / The short-term impact of high-speed rail (HSR) on land use: the empirical study of the Taiwan HSR

關仲芸, Guan, Jhong Yun Unknown Date (has links)
多年來,交通運輸與土地使用之交互影響關係受學界所廣泛討論,本研究主要探討高速鐵路與土地使用之交互影響關係。關於高鐵對土地使用影響之研究,分為兩大類別,分別為建立模式預測未來地區發展狀況,以及實證分析高鐵通車後對地區的影響效果。過去研究指出,高鐵營運後,可能對土地使用產生之影響包括:無顯著之土地使用改變、地區間互動改變、聚集效果(Cluster effect)、離散效果(Disparties)以及「隧道效果(Tunnel effect)」或「廊道效果(Corridor effect) 」。   本研究為以階層線性模型分析高鐵通車後對台灣土地使用影響之實證研究。根據實證,高鐵站之有無以及高鐵站所在區位對鄉鎮市區土地使用有顯著影響,且相較其他控制變數,為影響鄉鎮市區土地使用之重要變數。有高鐵站之鄉鎮市區與無高鐵站之鄉鎮市區相比,土地使用可能成長較多,而位於高鐵一定服務範圍內之鄉鎮市區之土地使用,亦受高鐵所影響。另外,不同區位之高鐵站對土地使用之效果有所不同,而該區位效果隨產業特性可能有所差異。人口、及業人口以及三級產業及業人口可能因市中心區位之高鐵站聚集,但二級產業及業人口未有因市中心區位高鐵站而聚集的現象;郊區區位之高鐵站鄉鎮市區或縣市,則有人口、及業人口或三級產業及業人口流失的現象。由上述結果可驗證,高鐵服務範圍內有聚集效果之發生,而不同區位之高鐵站,聚集之效果並不同。 / For many years, the interactive relationship between transportation and land use has been widely discussed by scholars. This study is trying to assess the short-term impact of high-speed rail (HSR) on land use. There are two types of studies on the impact of high-speed rail on land use. One is establishing models to predict future land use development; the other is evaluating the effect of HSR empirically. Past studies have shown that possible impacts on land use after the operation of HSR include: no significant land use change, inter-regional interaction change, cluster effect, disparities, and "tunnel effect" or "corridor effect."   In this empirical study, the results of hierarchical linear model show that the existence of the HSR station and the location of the HSR station have a significant effect on the land use in the city. Controlling for other control variables, the existence and location of the HSR station are important factors influencing the land use in the city. Land use development in cities with the HSR station may be more evident than those without the HSR station. Cities within the HSR service area are also effected by HSR. In addition, there may be different land use effects due to different locations of the HSR stations, and these location effects may be different due to different industrial characteristics of the area. Population, employment, and employment of tertiary industrial sectors in a city may cluster due to the HSR station in central area location, but employment of secondary industrial sectors doesn’t. Otherwise, population, employment, and employment of tertiary industrial sectors in a city or county may lose due to the HSR station in rural area location. In conclusion, there is a cluster effect within the HSR service area, and this effect varies according to the location of the HSR station.
18

Air Transport versus High-Speed Rail: From Physics to Economics

Gregorian, Hayk January 2019 (has links) (PDF)
Purpose - This bachelor thesis compares high-speed rail (HSR) transport with air transport. The investigation considers physical fundamentals, energy consumption, environmental impact, infrastructure and investment, market situations, passenger's selection criteria to choose transportation options, and overall economics. --- Methodology - The thesis combines an investigation of physical principles with a literature review. --- Findings - Steel wheels on steel rails show by far less rolling resistance to support the train's weight than drag due to lift (induced drag) to support the aircraft's weight. This leads to less energy consumption. HSR trains use electricity from an overhead line. Hence, the environmental impact of HSR also depends much on how the electricity is produced. Airplanes only need an air traffic control environment to connect airports. In contrast, HSR needs infrastructure to connect stations. The amount of necessary infrastructure depends on the geological conditions. For example, crossing mountains means high investment. Longer passages over water are infeasible for HSR. High-speed rail is superior to air transport when connecting megacities because the trains have higher transport capacity, offer higher service frequencies and mission reliability, shorter total travel time, shorter access time to stations, shorter unproductive waiting time in stations and potentially lower travel costs. HSR is a strong competitor to airline services and has replaced some short range flights. A comparison of HSR in different world regions shows differences in the market situation and in passenger's selection criteria for transportation options. --- Research limitations - The potential of high-speed rail was investigated mainly on busy routes with high service frequencies. A comprehensive network comparison between high-speed trains and airplanes was not done and could lead to somewhat different results. --- Practical implications - The report tries to contribute arguments to the discussion about alternatives to air travel. --- Social implications - With more knowledge people can make an educated choice between transport options, can vote with their feet, and can take a firm position in the public discussion. --- Originality/value - A general comparison of HSR and air transport from physical fundamentals to economics seemed to be missing.
19

Coupling source term, mineral reactivity and flow in radionuclide transport

Iwalewa, Tajudeen January 2017 (has links)
The focus of this work is to investigate the dissolution of MW25, a non-radioactive simulant of UK high-level nuclear waste borosilicate glass, and to predict its performance in the near field of a geological repository. A single-pass flow-through (SPFT) experimental system was used to measure the forward dissolution rates of MW25. Experiments were conducted in two parts. Experiment Part 1 considers the dissolution of the waste glass in deionised water at 40 and 90 oC and circum-neutral pH. Experiment Part 2 considers the dissolution of the waste glass in simulant groundwaters, with similar compositions to groundwaters of Callovo-Oxfordian clay (lower-strength sedimentary rock (LSSR)) and Borrowdale Volcanic Group rocks (higher-strength rock (HSR)), at 40 oC and pH 7. The forward dissolution rate measured in deionised water was found to be approximately one order of magnitude higher at 90 oC than at 40 oC. A similar release was observed for Si, Mg and Al at 40 oC and 90 oC, whereas the B, Cs, Na, Li and Mo showed an order of magnitude increase when the temperature was increased from 40 to 90 oC for low q/S values. The activation energy (Ea) of the reactions shows that the dissolution process is a surface phenomenon. At 90 oC the net effect of the processes governing MW25 dissolution led to the preferential release of boron and alkali metals relative to the release of Si during the transient dissolution stage, accompanied by an increase in the concentration of silicic acid. This suggests that the solution activity of silicic acid at a higher temperature has a weak influence on the release of the mobile elements. The forward dissolution rate measured in LSSR simulant groundwater was found to be slightly higher than that measured in HSR simulant groundwater. The dissolution behaviour of MW25 in both groundwaters is consistent with its behaviour in deionised water at 40 oC, with the dissolution rates of elements increasing as flow rates were increased. However, forward dissolution rates measured in the simulant groundwaters were lower than the forward dissolution rates measured in deionised water under these experimental conditions. This is attributable to the interaction of the components of the simulant groundwaters with the glass, as revealed by post-reaction surface analyses, and a consequential lower alkalinity of the leachates collected in the experiments with simulant groundwater than in deionised water. Reactive chemical transport simulations of waste glass dissolution and radionuclide release in a hypothetical near field were conducted over a time span of a million years with GoldSim. The results showed that enclosing the waste glass in a steel canister covered by a copper canister and emplacing the waste package in a granite host rock is optimal for the long-term isolation of the radionuclides. The waste glass was found to play a significant role in the overall performance of the near field. This study features a new method for estimating the surface area of reacted glass powder more accurately than the geometric surface area estimate, which is the preferred standard method among researchers.

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