Imaging speed is an important issue in magnetic resonance imaging (MRI), as subject motion during image acquisition is liable to produce artifacts in the image. However, the speed at which data can be collected in conventional MRI is fundamentally limited by physical and physiological constraints. Parallel MRI is a technique that utilizes multiple receiver coils to increase the imaging speed beyond previous limits by reducing the amount of acquired data without degrading the image quality. In order to remove the image aliasing due to k-space undersampling, parallel MRI reconstructions invert the encoding matrix that describes the net effect of the magnetic field gradient encoding and the coil sensitivity profiles. The accuracy, stability, and efficiency of a matrix inversion strategy largely dictate the quality of the reconstructed image. This thesis addresses five specific issues pertaining to this linear inverse problem with practical solutions to improve clinical and research applications. First, for reconstruction algorithms adopting a k-space interpolation approach to the linear inverse problem, two methods are introduced that automatically select the optimal k-space subset samples participating in the synthesis of a missing datum, guaranteeing an optimal compromise between accuracy and stability, i.e. the best balance between artifacts and signal-to-noise ratio (SNR). While the former is based on cross-validation re-sampling technique, the second utilizes a newly introduced data consistency error (DCE) metric that exploits the shift invariance property of the reconstruction kernel to provide a goodness measure of k-space interpolation in parallel MRI. Additionally, the utility of DCE as a metric for characterizing and comparing reconstruction methods is demonstrated. Second, a DCE-based strategy is introduced to improve reconstruction efficiency in real time parallel dynamic MRI. Third, an efficient and reliable reconstruction method that operates on gridded k-space for parallel MRI using non-Cartesian trajectories is introduced with a significant computational gain for applications involving repetitive measurements. Finally, a pulse sequence that combines parallel MRI and multi-echo strategy is introduced for improving SNR and reducing the geometric distortion in diffusion tensor imaging. In addition, the sequence inherently provides a T2 map, complementing information that can be useful for some applications.

Yes / Chests were a ubiquitous part of medieval church furniture across Britain and Europe. Late 19th and early 20th century scholars believed that one type, the dug-out chest, was devoid of technical skill, and as such, confined to the earliest period of chest chronology. Perhaps as a result of the ‘primitive’ label, dug-outs remain relatively under-studied in relation to other types of chests and surprisingly few attempts have been made to validate ideas about their early origin through scientific dating. The current study uses dendrochronology to directly date a selection of dug-out chests, almost doubling the number of dated chests of this type in England and producing the earliest absolute dates for their construction. Five dug-out chests from the case-study counties of Herefordshire and Worcestershire returned dates ranging from the 13th-16th century, showing that they are not chronologically confined to the ‘earliest’ period. This research also demonstrates how analysing extant saw-marks, along with the different methods of attaching chest lids, can assist in dating a chest’s construction. By understanding the tools and processes of construction, this research challenges the existing accepted framework that dug-outs are the ‘crudest’ and ‘most primitive’ type of church chest in the medieval period. Together these findings offer a new methodology and framework for studies of church chests in Britain and Europe. / This paper is based on research undertaken by Rachel Sycamore, as part of a Master’s by Research, at the University of Worcester (Sycamore, 2021). Funding for the dendrochronology was provided by the Regional Furniture Society.

Published scientific work indicates that residential large diameter drinking water wells are at a higher risk of contamination from surface water impacts than drilled wells. The possibility of a higher incidence of contamination of large diameter wells is attributed to site selection and construction problems such as leaking joints in the well casing, ineffective annular sealant placed between the well casing and the formation, a poorly fitted cover with an access lid that promotes contaminant entry and air entry without adequate air filtration, well location down gradient of septic effluent sources, and depth limitations due to improper equipment used to advance the well which results in shallow wells often situated in topographical lows. In some situations, flaws in the well design were actually deliberate measures intended to capture surface water at sites with low groundwater yield. Historically, residential drinking water well performance studies have focussed on existing wells; however, uncertainty in the actual well construction methods and materials, well age and maintenance efforts have been problematic. A field and laboratory study was completed to assess the performance of several design changes that were thought to improve the integrity of large diameter drinking water wells, and to determine whether one design is more prone to atmospheric and/or surface water contamination than the other. Four large diameter residential wells were installed at a study site in Lindsay, Ontario. Three of these wells are constructed with enhanced construction methods (two using a cement tile casing and one using a galvanized steel casing) and annular sealants, while the fourth was constructed using conventional methods for cement cased wells. The enhanced test wells utilized a sealant between the casing sections, various annular sealants between the formation and the well casing, sanitary waterline connections, and ventilation with air filtration. The well constructed using outdated methods did not have any of these advanced features. An automated water extraction system removed about 875 L/day from each well to mimic residential usage. Routine monitoring, and laboratory and field testing were used to collect pertinent data required for this performance assessment. Routine monitoring involved the visual inspection of the wells, collection of well water elevation, collection of soil temperature profile data, collection and analysis of water samples, and collection of cumulative water volumes purged from the test wells. A biofilm cleaning study and analysis of cement-bentonite grout was conducted in the laboratory while smoke and aqueous tracer tests were conducted in the field. The biofilm cleaning study entailed growing a biofilm on different large diameter well casing materials and applying cleaning methods thought to be practical for cleaning the interior walls of large diameter wells. Different mixtures of cement-bentonite grout were subjected to volume measurements, vertical load bearing capacity analysis, and hydraulic conductivity analysis to determine their suitability as a potential annular sealant. The tracer tests were developed to determine whether pathways for either airborne contaminants or surface water to enter the test wells exist. The test wells were filled with smoke and monitored for potential atmospheric pathways. A tracer solution was infiltrated around the test wells and the interior of the tests wells were monitored for potential pathways for surface water to enter. Bacteriological indicators were detected in all test wells. The smoke tracer tests demonstrated that pathways for airborne contaminants to enter the test wells exist with more pathways observed in the winter than the summer. The aqueous tracer tests highlighted several areas where surface water could enter the test wells if ponding occurred around the well casing. As expected the enhanced test wells performed much better than the conventional test well for both of these tracer tests. The results of the biofilm cleaning study indicated that galvanized steel or fibreglass casing materials were the only materials able to be cleaned effectively. The best method in this study to remove biofilm from casing materials was pressure washing. The results from the cement-bentonite grout investigation indicated that cement-bentonite grout with 5% bentonite would make the most suitable annular sealant as its volume changed the least during curing, it was strong enough to support the load from maintenance efforts, and was the most impervious. The results of this study indicate that large diameter wells constructed with a proper annular sealant, sealant between casing sections and a sanitary waterline connection are less prone to contamination. Monitoring of the test wells should continue as they mature to determine whether this plays a significant role in their ability to prevent contamination of large diameter wells. Smoke tracer tests should be conducted again during the winter to determine if temperature was the cause of increased atmospheric pathways. A field-scale method to remove biofilm from the interior casing wall of large diameter wells should be developed and tested. A field-scale investigation of cement-bentonite grout for use as an annular sealant should be completed. Fibreglass casings can be fabricated as a continuous piece with no seams or joints and hence another well should be constructed and studied using corrugated fibreglass (NSF ANSI 61) casing.

Published scientific work indicates that residential large diameter drinking water wells are at a higher risk of contamination from surface water impacts than drilled wells. The possibility of a higher incidence of contamination of large diameter wells is attributed to site selection and construction problems such as leaking joints in the well casing, ineffective annular sealant placed between the well casing and the formation, a poorly fitted cover with an access lid that promotes contaminant entry and air entry without adequate air filtration, well location down gradient of septic effluent sources, and depth limitations due to improper equipment used to advance the well which results in shallow wells often situated in topographical lows. In some situations, flaws in the well design were actually deliberate measures intended to capture surface water at sites with low groundwater yield. Historically, residential drinking water well performance studies have focussed on existing wells; however, uncertainty in the actual well construction methods and materials, well age and maintenance efforts have been problematic. A field and laboratory study was completed to assess the performance of several design changes that were thought to improve the integrity of large diameter drinking water wells, and to determine whether one design is more prone to atmospheric and/or surface water contamination than the other. Four large diameter residential wells were installed at a study site in Lindsay, Ontario. Three of these wells are constructed with enhanced construction methods (two using a cement tile casing and one using a galvanized steel casing) and annular sealants, while the fourth was constructed using conventional methods for cement cased wells. The enhanced test wells utilized a sealant between the casing sections, various annular sealants between the formation and the well casing, sanitary waterline connections, and ventilation with air filtration. The well constructed using outdated methods did not have any of these advanced features. An automated water extraction system removed about 875 L/day from each well to mimic residential usage. Routine monitoring, and laboratory and field testing were used to collect pertinent data required for this performance assessment. Routine monitoring involved the visual inspection of the wells, collection of well water elevation, collection of soil temperature profile data, collection and analysis of water samples, and collection of cumulative water volumes purged from the test wells. A biofilm cleaning study and analysis of cement-bentonite grout was conducted in the laboratory while smoke and aqueous tracer tests were conducted in the field. The biofilm cleaning study entailed growing a biofilm on different large diameter well casing materials and applying cleaning methods thought to be practical for cleaning the interior walls of large diameter wells. Different mixtures of cement-bentonite grout were subjected to volume measurements, vertical load bearing capacity analysis, and hydraulic conductivity analysis to determine their suitability as a potential annular sealant. The tracer tests were developed to determine whether pathways for either airborne contaminants or surface water to enter the test wells exist. The test wells were filled with smoke and monitored for potential atmospheric pathways. A tracer solution was infiltrated around the test wells and the interior of the tests wells were monitored for potential pathways for surface water to enter. Bacteriological indicators were detected in all test wells. The smoke tracer tests demonstrated that pathways for airborne contaminants to enter the test wells exist with more pathways observed in the winter than the summer. The aqueous tracer tests highlighted several areas where surface water could enter the test wells if ponding occurred around the well casing. As expected the enhanced test wells performed much better than the conventional test well for both of these tracer tests. The results of the biofilm cleaning study indicated that galvanized steel or fibreglass casing materials were the only materials able to be cleaned effectively. The best method in this study to remove biofilm from casing materials was pressure washing. The results from the cement-bentonite grout investigation indicated that cement-bentonite grout with 5% bentonite would make the most suitable annular sealant as its volume changed the least during curing, it was strong enough to support the load from maintenance efforts, and was the most impervious. The results of this study indicate that large diameter wells constructed with a proper annular sealant, sealant between casing sections and a sanitary waterline connection are less prone to contamination. Monitoring of the test wells should continue as they mature to determine whether this plays a significant role in their ability to prevent contamination of large diameter wells. Smoke tracer tests should be conducted again during the winter to determine if temperature was the cause of increased atmospheric pathways. A field-scale method to remove biofilm from the interior casing wall of large diameter wells should be developed and tested. A field-scale investigation of cement-bentonite grout for use as an annular sealant should be completed. Fibreglass casings can be fabricated as a continuous piece with no seams or joints and hence another well should be constructed and studied using corrugated fibreglass (NSF ANSI 61) casing.

Darbo tikslas – įvertinti šachtinių šulinių geriamojo vandens kokybę ir jo gerinimo galimybes Pakruojo rajone. Uždaviniai: 1. Įvertinti šachtinių šulinių geriamojo vandens kokybės rodiklius. 2. Nustatyti nėščių moterų ir moterų, kurios augina kūdikius iki 6 mėn. amžiaus, požiūrį į naudojamo vandens kokybę ir tyrimo rodiklius. 3. Įvertinti šachtinių šulinių geriamojo vandens kokybės gerinimo galimybes. Tyrimo metodika. Anketinė nėščių moterų ir kūdikius iki 6 mėn. amžiaus auginančių moterų (n=167, atsako dažnis 100 proc.) apklausa. Šachtinių šulinių geriamojo vandens kokybės rodiklių tyrimo protokolų analizė (n = 270) ir visuomenės sveikatos centro ir biuro specialistų, rajono ekologo (n=3, atsako dažnis 100 proc.) interviu. Apklausos duomenys analizuoti „SPSS 15.0 for Windows“ programa. Hipotezės tikrintos, taikant χ² testą, nustatčius reikšmingumo lygį p<0,05. Rezultatai. Tyrimo metu buvo nustatyta, kad respondentės, naudojančios užterštų šachtinių šulinių vandenį, dažniausiai gyvena kaimo vietovėse, turi mažas metines pajamas, yra bedarbės. 95,8 % respondenčių gavo informaciją apie šachtinių šulinių vandens kokybę ir patarimus, kaip apsaugoti save ir kūdikius. Moterys, turinčios žemesnį išsilavinimą, informavus apie vandens tyrimo rezultatus bei riziką sveikatai, vartoja užterštą geriamąjį vandenį nitratais ir nesiima jokių veiksmų jo kokybei gerinti. Netinkamai tvarkoma šulinio aplinka, kuri gali sąlygoti užteršimą: apie šulinį auginami augalai, kurie yra tręšiami... [toliau žr. visą tekstą] / The Aim of the study. To asses the quality of the possibilities of improving of water quality. Objectives : 1. Estimate the quality of drinking water. 2. Evaluate the attitude of pregnant women and the women growing up babies sunder the age of six (6) months to the wells water quality indicators. 3. Estimate the opportunities for improvements of quality of drinking water. Research methods. Questionnaire of pregnant women and the women raising infants under six months (n=167), response rate -100 percent. The analysis of the wells for drinking water quality indicators (n=270) was done by the public health center. Interview of the public health professionals of the region: (n=3, response rate 100 percent). Survey data, was analyzed at “SPSS15.0 for Windows” program. The Hypothesis is verified by using the test χ2 , significance level p<0,05. Results. 95.8 % of respondents have received enough information concerning the quality of the water in their wells. The women with lower education were informed about the test results of their water, about health risks using the water, but they still are using contaminated by nitrates drinking water and don’t take any actions to improve it’s quality. Improperly maintenance of wells and their environment may lead to contamination of drinking water: the plants growing near the wells are fertilized with organic fertilizers, sewage is loaded on the ground. The pregnant women with higher education show better knowledge for improvement of water... [to full text]

Self Supply Systems (SSS) can be defined as privately owned household level water sources. The research focus is on urban self supply hand dug wells in Abeokuta, Nigeria. Self supply wells serve an estimated 45% of Abeokuta’s population. SSS can be gradually upgraded to improve water quality, but water quality can also be improved through effective risk management. The World Health Organization (WHO) has developed a risk management tool known as Water Safety Plans (WSP), but the tool has not been tried for SSS. This research focuses on the relevance of the generic WHO water safety plans tool to SSS, with the aim to develop an appropriate water safety framework for self supply sources to ensure acceptable household water. Water from self supply wells is used for both ingestion and non-ingestion household activities. The water quality of the sources is poor and not safe for consumption with faecal coliform counts in excess of 100 cfu/100 ml of water. Self supply wells in Abeokuta are plagued by four main water safety threats; style of source operation – primarily through bucket and rope -, construction problems, proximity to sources of contamination, and user’s hygiene practices. Users are in denial of the health consequences of unsafe water. There is a predominantly reactive attitude to water safety management. The main source management approaches include access and hygiene management. To appropriate existing WSP to SSS, source and water safety control measures require user acceptability to be sustainable in terms of adoption and compliance. Incentives are needed for the adoption of SSS water safety plans. A two- phase supporting program is necessary: awareness and enlightenment campaigns and relevant training activities. Water safety development for self supply wells need to be initiated and coordinated by an established institution other than the source owners. This research suggests the Department of Public Health as the institution to facilitate the development of water safety plans for SSS in Abeokuta, Nigeria.

Darbo tikslas – įvertinti šachtinių šulinių geriamojo vandens kokybę ir jo gerinimo galimybes Pakruojo rajone. Uždaviniai: 1. Įvertinti šachtinių šulinių geriamojo vandens kokybės rodiklius. 2. Nustatyti nėščių moterų ir moterų, kurios augina kūdikius iki 6 mėn. amžiaus, požiūrį į naudojamo vandens kokybę ir tyrimo rodiklius. 3. Įvertinti šachtinių šulinių geriamojo vandens kokybės gerinimo galimybes. Tyrimo metodika. Anketinė nėščių moterų ir kūdikius iki 6 mėn. amžiaus auginančių moterų (n=167, atsako dažnis 100 proc.) apklausa. Šachtinių šulinių geriamojo vandens kokybės rodiklių tyrimo protokolų analizė (n = 270) ir visuomenės sveikatos centro ir biuro specialistų, rajono ekologo (n=3, atsako dažnis 100 proc.) interviu. Apklausos duomenys analizuoti „SPSS 15.0 for Windows“ programa. Hipotezės tikrintos, taikant χ² testą, nustatčius reikšmingumo lygį p<0,05. Rezultatai. Tyrimo metu buvo nustatyta, kad respondentės, naudojančios užterštų šachtinių šulinių vandenį, dažniausiai gyvena kaimo vietovėse, turi mažas metines pajamas, yra bedarbės. 95,8 % respondenčių gavo informaciją apie šachtinių šulinių vandens kokybę ir patarimus, kaip apsaugoti save ir kūdikius. Moterys, turinčios žemesnį išsilavinimą, informavus apie vandens tyrimo rezultatus bei riziką sveikatai, vartoja užterštą geriamąjį vandenį nitratais ir nesiima jokių veiksmų jo kokybei gerinti. Netinkamai tvarkoma šulinio aplinka, kuri gali sąlygoti užteršimą: apie šulinį auginami augalai, kurie yra tręšiami... [toliau žr. visą tekstą] / The Aim of the study: to asses the quality of the possibilities of improving it in Pakruojis district. Objectives : 1. Estimate the quality of the dug wells for drinking water. 2. Evaluate the standpoint of pregnant women and the women growing up babies sunder the age of six (6) months to the dug wells water quality indicators. 3. Estimate the opportunities of improvements for the quality of drinking water. Research methods. Questions for pregnant women and the women raising infants under six months Cn =167, response rate was 100 percent survey. The analysis of the dug wells for drinking water quality indicators (n=270) made by the public health center, the office professionals the region ecologist (n=3, response rate 100 percent) interview. Survey data, was analysed at “SPSS15.0 for Windows” program. The Hypothesis is verified by using the test χ2. According to it the significance level is p<0,05. Results. The study found out that the respondents using contaminated water from dug wells, are unemployed. 95.8 % of them have received the right information about the quality of the water in their dug wells. They also have get the advices how to protect themselves and their children. The women with lower education were informed about the test results of their water, about health risks using the water, they still consumpt contaminated by nitrates drinking water and don’t take any actions to improve its quality. Improperly handled wells, their environment which may lead to... [to full text]

Submitted by admin tede (tede@pucgoias.edu.br) on 2017-10-02T13:17:26Z No. of bitstreams: 1 IVÂNIA LUÍZA BARBACENA.pdf: 807552 bytes, checksum: 31474085bccd3d0c3588bc5bb5091910 (MD5) / Made available in DSpace on 2017-10-02T13:17:26Z (GMT). No. of bitstreams: 1 IVÂNIA LUÍZA BARBACENA.pdf: 807552 bytes, checksum: 31474085bccd3d0c3588bc5bb5091910 (MD5) Previous issue date: 2009-09-28 / A study of parameters that act on water quality in micro-watershed dug ponds is important because it enables a holistic approach aimed to promote better activity management and provide considerable information about the ecosystems involved. The aim of this study was to quantify physical and chemical parameters of water in dug ponds (small dams and tanks) of fish within a micro-watershed during a diurnal cycle. The field work was performed at days 08, 13, 18 and 23 of July 2009 in a small catchment of the Rio dos Bois, in the municipality of Cezarina, State of Goiás. The sampling occurred over a period of 24 hours with the collection every 6 hours in two different sites: the upstream and downstream of the ponds. To characterize the water quality parameters it was analyzed: weather temperature, water temperature, transparency, ammonia, hardness, alkalinity, dissolved oxygen, pH and orthophosphate. Comparing the parameters of water quality upstream and downstream of the ponds in the study, the figures show that there was no statistically significant differences ( > 0.05) between the points for the variable ambient temperature, water temperature, transparency, ammonia, hardness, alkalinity, dissolved oxygen and orthophosphate and showed a statistically significant ( <0.05) for the parameter pH. To optimize culture conditions, we suggest some techniques of Good Management Practices (GMP) adopted in aquaculture. / O estudo de parâmetros que atuam na qualidade da água em viveiros escavados em uma microbacia é importante porque permite uma visão holística direcionada no sentido de promover o melhor gerenciamento para a atividade bem como fornecer informações consideráveis a respeito dos ecossistemas aquáticos envolvidos. O objetivo do presente trabalho foi analisar quantitativamente parâmetros físicos e químicos da água em viveiros escavados (pequenas represas e tanques) de piscicultura dentro da microbacia rio dos Bois no município de Cezarina/GO ,durante um ciclo nictemeral. Os trabalhos de campo foram realizados nos dias 08, 13, 18 e 23 do mês de julho de 2009. A amostragem ocorreu em um período de 24 horas com coletas a cada 6 horas para coincidir as maiores e as menores temperaturas durante o dia e foram em dois pontos distintos: a montante e a jusante dos viveiros. Para caracterizar a qualidade da água foram analisados através de kits comerciais para análise de água doce, os parâmetros: temperatura do ambiente, temperatura da água, transparência, amônia, dureza, alcalinidade, oxigênio dissolvido, pH e ortofosfato. Comparando os parâmetros de qualidade da água de montante e jusante dos viveiros em estudo, os valores revelam que não houve diferenças estatisticamente significativas ( >0,05) entre os pontos para as variáveis temperatura do ambiente, temperatura da água, transparência, amônia, dureza, alcalinidade, oxigênio dissolvido e ortofosfato e que apresentou diferença estatisticamente significativa ( <0,05) para o parâmetro pH. Para otimizar as condições de cultivo, sugere-se algumas técnicas de Boas Práticas de Manejo (BPM) adotadas em aquicultura.

The first part of this thesis is focused on water wells and their classification. A big part of this thesis is an essay on groundwater. This thesis also examines the various technical parts of drilled wells and dug wells. The design of pump is discussed briefly. The second part of this thesis is focused on objective and financial complexity of proposed solutions.