Landfill covers are designed as impermeable caps on top of waste containment facilities after the completion of landfill operations. Geocomposite drain (GD) materials consist of a geonet or geospacer (as a drainage core) sandwiched between non-woven geotextiles that act as separators and filters. GD provides a drainage function as part of the cover system. The stability performance of landfill cover system is largely controlled by the interface shear strength mobilised between the elements of the cover. If a GD is used, the interface shear strength properties between the upper surface of the GD and the overlying soil may govern stability of the system. It is not uncommon for fine grained materials to be used as cover soils. In these cases, understanding soil softening issues at the soil interface with the non-woven geotextile is important. Such softening can be caused by capillary break behaviour and build-up of water pressures from the toe of the drain upwards into the cover soil. The interaction processes to allow water flow into a GD core through the soil-geotextile interface is very complex, and have been defined herein as Capillary Related Interface Breakthrough (CRIB). The infiltration test using small column on CRIB conditions for GD in contact with fine grained soils confirmed the development of capillary break at the interface. The effect of water build-up on the interface leads to soil softening in fine grained soils layer and reduce the interface shear strength hence potential instability of the system. Two series of fine grained soil/GD interface shear strength tests conducted to determine the interface shear strength behaviour for a range of soil water contents. The soil softening at the interface due to soaked behaviour show a reduction in interface shear strength and this aspect should be emphasized in design specifications and construction control. Comparison on the main behaviour using field measurements on the trial landfill cover at Bletchley were conducted to increase confidence in the understanding of the implications for design of cover systems.

Orientador: Carlos Alberto dos Reis Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T14:40:24Z (GMT). No. of bitstreams: 1 Castaldo_FernandoCardoso_D.pdf: 30688674 bytes, checksum: 38148b8964d0d87ceacc943afb795fbc (MD5) Previous issue date: 2005 / Resumo: Este trabalho aborda a questão da compatibilidade eletromagnética em circuitos chaveados integrados, tipicamente conversores DC-DC dedicados. Neste sentido, propõe-se uma técnica de controle da emissão eletromagnética baseada no sensoriamento do campo magnético próximo através da utilização de transistores MOS do tipo split-drain. Desta forma, pode-se integrar conjuntamente o transistor de potência e o split-drain. O sinal produzido pelo sensor pode ser enviado a um circuito de acionamento que controla a derivada da corrente no transistor de potência, limitando, desta forma, a emissão gerada. Entretanto, o ruído associado ao transistor split-drain limita severamente a resolução do sensor. Estudos realizados indicaram a existência de uma corrente de ruído em excesso observada através de medidas de correlação de ruído, denominada corrente de ruído transversal. Esta corrente limita a relação sinal-ruído do sensor magnético, principalmente no modo diferencial, com impacto direto na resolução do sistema detector. A partir do entendimento dos mecanismos de geração de ruído investigados, circuitos detectores de campo magnético que atendam determinada resolução podem ser projetados, viabilizando-se assim, a implementação de sensores de emissão eletromagnética / Abstract: This work deals with the electromagnetic compatibility (EMI) issues aimed to power integrated circuits, typically DC-DC converters. An EMI controlling approach based on magnetic near field measurements using CMOS split-drain transistors (MAGFETS) as magnetic sensors is investigated. Monolithic applications can be envisaged comprising the power circuit and the magnetic sensor. The detected signal can be sent to a slew-rate-based controlling driver that sets the electromagnetic emissions below a specific leveI. However, the electronic noise associated with the split-drain transistor affects the sensor resolution. In this sense, it was observed through correlation measurements an excess noise current associated with the split-drain transistor, called transversal noise current. A noise model taking into account the transversal noise current is proposed, allowing the implementation of magnetic sensors featuring a specific resolution aimed to electromagnetic emissions detectors / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica

This thesis evaluates domestic water heating systems in conjunction with energy saving technologies such as solar water heating, drain water heat recovery, and heat pump water heating. Five dynamic models are developed using Matlab Simulink® with a time-step of one minute. Using minute resolution hot water flow, hourly solar radiation data and ambient temperature, the performance of various configurations are assessed when operating in Victoria, Kamloops, and Williams Lake, B.C. Twelve different demand profiles on a summer day and winter day are simulated. Some specific metrics, such as conventional energy consumption, system energy factor, and equivalent CO2 emissions are used as the basis of evaluating the system efficiency. Results indicate the potential improvements in system performance over a conventional domestic water heating system in lower conventional energy consumption and lower CO2 emissions when applying any one of the three energy saving technologies mentioned above. For example, on a representative summer day (Day 228) in Victoria with a load profile of a low-use two-person family on a weekday, the system‟s energy factor can be improved from 0.50 to up to 2.84, and the corresponding conventional energy consumption and the CO2 emissions decrease from 9.86 kwh to 1.67 kwh, and 1.77 kg/day to 0.06 kg/day, respectively depending on which energy saving technology is applied. The modeling tool developed in this research can be used to guide the design of domestic water heating systems with various system configurations. / Graduate

Brain drain of Kazakhstan in 1999-2008 Abstract The objective of this study is to analyze and evaluate the main trends and development of brain drain process in Kazakhstan for period from 1999 to 2008. Several key topics are discussed in this work: the economic and social context of skilled migration: employment patterns of highly skilled persons in Kazakhstan; the role of educational migration. In the first part of the work was given general patterns of brain drain in the world and overview of relevant literature. In the second part were analyzed trends of highly skilled migration in Kazakhstan. The data are taken from censuses and other relevant data sources. The data collection is provided by the Agency of Statistics of the Republic of Kazakhstan. Keywords: brain drain, migration, socio-economical situation, remittances, oralmans, education.

The presence of moisture in the soil reduces its shear strength. After the rain or snowmelt, the high percentage of moisture in the subgrade of highway, causes the instability resulting into failure of the highway due to high water table. Therefore, it is essential to install a drainage system to remove the excess moisture from the subgrade of highways to avoid its failure. In the present study, six different soil samples have been studied to observe its failure by triaxial shear strength and corresponding moisture content was noted. The tension applied to remove moisture was converted to equivalent drain depth. The relationships were studied between shear strength versus drain depth and moisture content versus drain depth. From these relationships the design drain depth for different types of soils studied was recommended. The present study also suggest that the design drain depth for the highways can be approximated directly using water retention curve.

Headwater streams are considered to be the greatest contributor to nonpoint source and are a crucial part of overall watershed dynamics because they comprise more than 50-80% of stream networks and watershed land areas. This study addressed the influence of headwater areas (ephemeral and intermittent) on downstream hydrology and water quality following harvest as well as characteristics of vegetation communities within three first-order catchments in the Upper Gulf Coastal Plain of Mississippi. Four treatments representing a range of potential Best Management Practices (BMPs) for ephemeral drains were used: BMP1 - removal of all merchantable stems while leaving understory intact with minimum surface soil disturbance; BMP2 - same as BMP1 with the addition of logging debris to the drainage channel; No harvest - left uncut as a reference; Clearcut - total harvest with no BMPs applied. Harvested treatments caused the height of water table to increase up to 55 cm; however impacts of timber harvesting on peak discharge, storm discharge, and time of concentration were not consistent with water table response. Response time to stormflow was reduced significantly in harvested treatments (BMP2 and unrestricted harvest) as a result of decreased evapotranspiration and increased soil disturbance. Forest clearcutting in ephemeral drains caused intensive surface soil disturbance that resulted in substantial impacts to net soil erosion/deposition in both channel and hillslope positions and significantly increased total suspend sediment (TSS). There were no significant differences between two BMP and reference treatments in net soil erosion/deposition and TSS. Distinct vegetation communities between channel and hillslope positions in ephemeral-intermittent drains corresponded to water table gradients. Timber harvesting affected vegetation communities through direct and indirect disturbances. Four indicator species (V. blanda, L. glandulosa, A. gigantean, and P. acrostichoides) were identified as having a strong response to hydrologic gradients in ephemeral-intermittent drains.

Introduction: Routine drain placement is still widely used in both sleeve gastrectomy (SG) and Roux en Y gastric bypass (REYGB). There is mounting evidence that drains may increase complication risk without preventing reoperation or other complications. Methods: Data from 2017 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Participant Use File was evaluated for drain use during laparoscopic REYGB and SG. Primary outcomes were superficial and deep surgical site infections (SSI), reintervention/reoperation, and readmission. Preoperative patient risk factors were also compared to evaluate for association with drain placement. Results: A total of 148 260 patients fit the inclusion criteria. Drains were used in 23 190 (15.6%) cases and not used in 125 070 (84.4%). Drain placement during surgery was associated with increased odds of superficial SSI, deep incisional SSI, and organ space SSI. Patients with drains were found to have increased odds of requiring at least 1 reoperation or intervention within 30 days of surgery. Preoperative risk factors associated with drain placement included diabetes mellitus, a history of chronic obstructive pulmonary disease, and oxygen dependence. Smokers were slightly less likely to have a drain placed. There was no significant association with chronic steroid and immunosuppressant usage. Conclusion: There is mounting data against drain placement during bariatric surgery. Prior studies using MBSAQIP data have shown an increased complication rate with drains, and our data set supports the idea that drains may increase complications after surgery. While no randomized prospective trials have been performed looking at drain usage in bariatric surgery, the growing retrospective data certainly inform against the regular use of drains.

Consolidation theory states that decreasing the spacing of prefabricated vertical drains will decrease the time required to achieve primary consolidation. Previous field tests have shown that there exists a "critical" drain spacing, which is the point at which further spacing decrease does not decrease the time of primary consolidation. This "critical" spacing is thought to be due to disturbance effects from installation of the drains. Previous studies have found that the "critical" drain spacing may be dependent upon soil layering and drain and mandrel dimensions. Thin, interbedded clay layers have been found to be affected greatly due to the smear zone, while few tests have been conducted to determine the validity for thick bedded clays. Currently two design and analysis methods are in existence, neither of which is standardized. The two methods are the modeling of the smear zone, which requires knowledge of soil parameters within that zone, and the modeling using a back-calculated Ch/Cv ratio.In order to evaluate the validity of these design methods and to obtain more data that can be used in determining the relationship between anchor type, drain spacing, and soil profile, full-scale field tests were conducted at Mountain View Corridor in Lehi, Utah. These field tests were performed along a test section that was divided into sections containing 5.8, 5.0, 4.0 and 3.0 ft triangular spacings and rebar or plate anchors. By using the smear zone model, with a Ch/Cv ratio of 1.25 and ds of 3.07 times dm, the time rate of settlement was able to be predicted reasonably well, while using the back-calculated Ch/Cv ratio, with no smear zone, also predicted the time rate reasonably well. From the testing, it was found that the thick clay profile can facilitate closer spacings than a thin clay profile. Also, it was found that the rebar anchor type causes about twice the disturbance of the plate anchor. The results helped validate the existing models and show that the effectiveness of the drains is dependent upon drain spacing, soil profile, and anchor type

No description available.

No Brasil, os solos hidromórficos são basicamente utilizados no cultivo de arroz, principalmente na região Sul do Brasil. O plantio de outras culturas em substituição ao arroz, pode ser uma alternativa viável para a melhor exploração destes solos durante o inverno e no pousio da área. O presente trabalho foi realizado em casa de vegetação do Departamento de Engenharia Rural da Escola Superior de Agricultura "Luiz de Queiroz" em Piracicaba, SP, tendo como objetivos avaliar os efeitos do rebaixamento do nível freático no desenvolvimento e na produtividade de plantas de soja, cv. BR-16 e de ervilha, cv. Axé, pelos parâmetros produtivos: altura e massa seca da parte aérea da planta, número de vagens e de grãos produzidos e peso total de grãos por planta; determinar o estádio de desenvolvimento das culturas mais sensível ao excesso de umidade no solo e determinar a velocidade de rebaixamento do nível freático mais adequada ao desenvolvimento das plantas de soja e de ervilha, dentro das condições experimentais propostas. As plantas foram conduzidas em lisímetros construídos em tubos de concreto preenchidos com Latossolo Vermelho-Amarelo Álico. Os ensaios foram realizados nos estádios vegetativo e reprodutivo das culturas, com o rebaixamento do nível freático (NF) em 10, 20, 30, 40 e 60 cm por dia e comparando-se com um tratamento de controle, somente irrigado. O delineamento experimental adotado foi inteiramente casualizado, arranjado em esquema fatorial [(2x5)+1], com 4 repetições. Os efeitos do rebaixamento do NF foram observados na massa seca da parte aérea das plantas, número de vagens, número de grãos por planta e peso de grãos em soja e ervilha, em comparação com as plantas testemunhas. O peso de grãos de soja produzidos em plantas inundadas durante o estádio reprodutivo, foi 3% maior do que verificado na testemunha, indicando que certos períodos de inundação podem aumentar o peso de grãos. Já as plantas de soja inundadas no estádio vegetativo apresentaram reduções significativas de 37% do peso do grão, demonstrando maior susceptibilidade à inundação neste estádio. Foram observadas reduções no peso de grãos de ervilha em ambos os estádios, sendo o reprodutivo o mais afetado (52%). Os efeitos causados pela inundação do solo, observados no número de vagens e de grãos produzidos pelas plantas de soja e de ervilha foram proporcionais ao tempo em que as raízes permaneceram submersas e variaram com a cultura e com estádio de desenvolvimento da planta. Acredita-se que velocidades de rebaixamento do NF superiores a 30 cm por dia são capazes de promover uma adequada aeração do solo, situação observada na rápida recuperação das plantas de soja inundadas no estádio vegetativo e submetidas ao rebaixamento do NF em 30 cm por dia e também no aumento da taxa de transpiração das plantas de ervilha submetidas à inundação do solo no estádio vegetativo e reprodutivo, após o rebaixamento de 30 cm do NF. O maior prejuízo à produtividade das culturas foi causado pela velocidade de rebaixamento do NF em 10 e 20 cm de profundidade. / In Brazil, most of hidromorfic soils are cultivated with rice. The growth of alternative crops to rice, is a feasible option for better use of hidromorfic soils. The present work was realized in the Department of Rural Engineering of Escola Superior de Agricultura "Luiz de Queiroz" in Piracicaba, São Paulo - Brazil. The objectives were to study the effects of the water table drawdown in the growth and crop yield of soybean, cv. BR-16, and pea, cv. Axé, at specific stages of their cycle. Yield parameters for these crops were valuated, such as: plant height, dry shoot weight, number of pods per plant, number of seed per plant and seed weight per plant. Also, to determine the growth stage of crop clycle more sensitive to waterlogging and the more appropriate velocity of water table lowering for to development of soybeans and peas plants, by the analysis of the yield parameters, in the experimental conditions proposed. Both crops were cultivated in lysimeters in a greenhouse. The soil used was the Orthic Hapludent. The study was realized in the vegetative and reproductive crop stages. The water table was lowered by 10, 20, 30, 40 e 60cm per day, from initial level. Control plants where only irrigated without flooding. The statistical experimental design was a randomized complete in factorial arrange [(2x5) + 1] with four replications. The effects from different drawdown velocity of water table, were observed in the all parameters in comparison with the control. For soybean, waterlogging during reproductive stage, caused a higher seed weight than control without waterlogging, showing that short waterlogging periods may increase seed weight. The waterlogging of plants at the vegetative stage crop cycle, showed significant reductions in seed weight in all treatments, indicating low waterlogging tolerance. In pea, the seed weight showed for all treatments was lower than control plants. The effects caused by waterlogging of the soil the number of the pods and soybean and pea seed, were proportional to root flooding time and to development stage of the plant. By physiologic responses of the soybeans and pea plants, was possible to determine that the lower limit of reduction of the water table was the 30 cm per day. The water table lowering by 10 and 20 cm per day severely affected the growth and seed yield, in the experiment conditions.