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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.
1

Biofilm-Enhanced Treatment for Arctic Wastewater Stabilization Ponds Using Geotextile Substrate

Bridson-Pateman, Evan 12 August 2013 (has links)
In this thesis, a semi-permeable lining system was proposed to upgrade arctic wastewater stabilization ponds, acting as a biofilter. Although commonplace at lower latitudes, the effects of cold temperatures and short-duration summers on biofilter performance are inadequately studied. The goal of this research was to study the hydraulic and treatment performance of geotextile substrate biofilters under arctic conditions. Filtration experiments were conducted in a laboratory environment. Municipal wastewater was passed through columns containing nonwoven geotextiles over 10 cm of gravel. Three experimental trails were conducted at either 10? or 2?, each lasting 12 weeks. Weekly samples taken before and after filtration were analyzed for various water quality parameters. Hydraulic conductivity was monitored using weekly constant head permeameter tests. Results showed that biomat accumulation is possible on geotextile material over 12 week period. Significant removal of TSS and BOD5 was observed, along with a 1-log reduction in hydraulic conductivity.
2

An?lise histomorfom?trica comparativa entre o cimento de α-TCP e os gr?nulos de β-TCP/HA no reparo ?sseo de calotas cranianas de ratos

Grandi, Gisela 13 December 2007 (has links)
Made available in DSpace on 2015-04-14T13:29:17Z (GMT). No. of bitstreams: 1 397726.pdf: 6415316 bytes, checksum: 94e18040fb876738a7854d94d6e2b15c (MD5) Previous issue date: 2007-12-13 / Os defeitos ?sseos podem decorrer de fatores como patologias, traumas e cirurgias. Dependendo de sua extens?o, o reparo ?sseo n?o acontece de forma espont?nea, necessitando o uso de enxertos. Os biomateriais t?m sido uma alternativa vi?vel como substitutos ?sseos. Dentre eles, destacam-se as biocer?micas pela sua biocompatibilidade, atoxicidade e propriedades osteocondutoras. Este estudo analisou comparativamente dois tipos de biocer?micas, cimento de α-fosfato tric?lcico (α−TCP) e gr?nulos de β-fosfato tric?lcico-HA (β-TCP/HA), inseridas em defeitos ?sseos cr?ticos confeccionados em calotas cranianas de 50 ratos (Rattus norvegicus albinus, Wistar), machos, adultos, com peso corporal m?dio de 300 a 400g. Os animais foram divididos em dois grupos com 25 animais: grupo-α e grupo-β/HA. Na calota craniana de cada animal, foram confeccionadas duas cavidades medindo 4 mm de di?metro cada. A cavidade esquerda foi preenchida pelo material correspondente de cada grupo e a cavidade direita foi preenchida por co?gulo sang??neo aut?geno, correspondendo ao grupo controle. Os animais foram mortos aos 7, 21, 60, 90 e 120 dias de p?s-operat?rio. Os ossos parietais contendo as cavidades foram removidos e as pe?as operat?rias submetidas a processamento histol?gico pela t?cnica de HE. Com aux?lio do software Image Pro Plus 6.2, foi realizada an?lise histomorfom?trica que permitiu mensurar a ?rea de osso neoformado dos defeitos nos diferentes per?odos de observa??o. Os resultados, expressos em porcentagem m?dia de ?rea do defeito preenchido por osso neoformado, no grupo α−TCP foram: 1,6% (+ 2,37) aos 7 dias, 5,24% (+ 5,58) aos 21 dias, 24% (+ 14,5) aos 60 dias, 30,21% (+ 6,84) aos 90 dias e 50,59% (+ 5,42) aos 120 dias. No grupo β−TCP/HA, os resultados foram de 1,94% (+ 3,10) aos 7 dias, 2,53% (+ 1,19) aos 21 dias, 12,47% (+ 3,87) aos 60 dias, 26,84% (+ 2,80) aos 90 dias e 38,82% (+ 8,76) aos 120 dias de p?s-operat?rio. No grupo controle, as m?dias dos resultados foram de 0,15% aos 7 dias, 10,12% aos 21 dias, 15,10% aos 60 dias, 18,94% aos 90 dias e 48,50% aos 120 dias. Conclui-se que o cimento α-TCP e os gr?nulos β−TCP/HA promovem osteocondu??o; o cimento α-TCP ? mais sol?vel e apresenta maior porcentagem de ?rea de neoforma??o ?ssea. Os gr?nulos β−TCP/HA s?o reabsorvidos mais lentamente, o que parece promover manuten??o do volume da regi?o implantada
3

The Spatial Relationship Between Septic System Failure and Environmental Factors in Washington Township, Marion County, Indiana

Hanson, Brian L. 04 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Underground septic systems thrive or fail based on the relationship with their local environment. This paper explores ways environmental variables such as soil type, tree roots, degree of slope, and impervious surfaces affect on-site wastewater treatment systems. It also discusses the effects each of these variables may have on a septic system, and the resulting impact a compromised system may have on the surrounding environment. This research focuses on an approximately 20 square mile area of central Washington Township in Marion County, Indiana. This area of central Indiana contains a large septic system owning population in a sampling of different environments such as wooded areas, hilly areas, and a variety of different soil types.

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