• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 5
  • 4
  • 4
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 64
  • 64
  • 35
  • 16
  • 15
  • 14
  • 13
  • 11
  • 10
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 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.
61

Action Programs for Water Yield Improvement on Arizona's Watersheds: Political Constrains to Implementation

Cortner, H. J., Berry, M. P. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Although the Arizona Watershed Program 's (AWP) research efforts have had considerable success over the past 22 years in its objective to further knowledge of the feasibility of vegetative manipulation and modification as a method of increasing surface water yields, its principal sponsor and supporter, the Arizona Water Resources (AWRC), has not, to date, met with similar success. Described are three of the AWRC 's unsuccessful attempts to implement on-going action programs of vegetative management for water yield improvement: The Barr Report, the Ffolliott-Thorud Report, and the Globe Chaparral controversy, to illustrate how overstated program goals, unrealistic assumptions about the political feasibility of treatment types, extent, and intensity; failure to recognize the emergence of significant new decision-making participants, and unsettled questions concerning program costs and beneficiaries have contributed to setbacks in these programs. It is suggested that political as well as scientific constraints have accounted for reported failures in the implementation of the AWP action program objectives.
62

Evolução das doses no ambiente do Reator IEA-R1 e tendências com base nos resultados atuais / The evolution of doses in THE IEA-R1 reactor environment and tendencies based on the current results

TOYODA, EDUARDO Y. 26 August 2016 (has links)
Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-08-26T11:43:46Z No. of bitstreams: 0 / Made available in DSpace on 2016-08-26T11:43:46Z (GMT). No. of bitstreams: 0 / O Ipen/Cnen-SP possui um Reator de Pesquisa(IEA-R1) em operação desde 1957. Ele utiliza água leve como blindagem, moderador e como fluido refrigerante, o volume desta piscina é de 273m3. Até 1995 a operação do Reator era descontinua, ou seja, operava diariamente sendo desligado no final do dia, a uma potência de 2,0 MW. A partir daquele ano, após algumas modificações de segurança, o Reator passou a operar de forma continua, ou seja, de segunda-feira a quarta-feira sem ser desligado, totalizando 64 horas semanais. A potência também foi aumentando até 4,5 MW em 2012. Em virtude dessas alterações, a saber, operação contínua e do aumento da potência, as doses dos trabalhadores aumentaram e por isso foram realizados vários estudos para diminui-las. Estudos demonstraram que uma das principais limitações para operação de um reator em potência elevada, provém das radiações gama emitidas pelo sódio-24. Outros elementos como magnésio-27, Alumínio-28, Argônio-51, contribuem de forma considerável para a atividade da água da piscina. A introdução de uma camada de água quente em sua superfície, estável e isenta de elementos radioativos com 1,5m a 2m de espessura constituiria uma blindagem às radiações provenientes dos elementos radioativos dissolvidos na água. Estudos de otimização provaram que a instalação da camada quente não era necessária para o regime e potência atual de operação do Reator, pois outros procedimentos adotados eram mais eficazes. A partir desta decisão o serviço de Proteção Radiológica do Reator IEA-R1, montou um programa de avaliação das doses para certificar-se de que elas se mantinham em valores razoáveis baseados em princípios estabelecidos em normas nacionais e internacionais. O intuito deste trabalho é realizar uma análise das doses individuais dos IOE (Individuo Ocupacionalmente Expostos), considerando as mudanças no regime de operação do Reator e sugerir opções de proteção e segurança, viáveis em primeira instância, para reduzir as doses analisadas, visando se chegar aos níveis de referencia de 3 mSv/ano adotados pela instalação em apreço. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
63

Stanovení reziduí léčiv pomocí separačních metod / Determination of drug residuals using separation methods

Vašíčková, Petra January 2010 (has links)
Nonsteroidal anti-inflammatory substances became a very frequently used and constantly evolved group of the drugs, particularly in a human medicine. The risk of their penetration into the environment, especially to the water environment, is rising during the recent years. The diploma thesis is focused on a selection of appropriate separation method and optimization of analytical procedure for the identification and determination of the non-steroidal anti-inflammatory drugs in sewage and surface waters. Salicylic acid, ketoprofen, diclofenac and ibuprofen were chosen from the wide range of NSAIDs as the most widespread agents of this drugs group in the medical practice. The method was optimized and elaborated using the model water samples. This method was used for determination of the analytes contained in the real water samples. Waste water samples were taken from the large-scale wastewater treatment plant in Brno-Modřice and surface water samples were taken from the Highlands river Křetínka. Solid phase extraction (SPE) was used for the real samples treatment and preconcentration, the determination was performed using the high performance liquid chromatography with mass spectroscopy method (LC-MS).
64

Hydrology as a Science?

Dvoracek, M. J., Evans, D. D. 06 May 1972 (has links)
From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Experimental and historical development of the systematic study of water is briefly reviewed to prove hydrology a science. The hydrology program at the university of Arizona is outlined, and details of the course 'water and the environment' are expounded. This introductory course is intended for non-scientific oriented students at this southwestern university. A reading list is provided for the class, and scientifically designed laboratory experiments are developed. The first semester includes discussion of world water inventory; occurrence of water; hydrologic cycle; interaction of oceanography, meteorology, geology, biology, glaciology, geomorphology and soils; properties of water (physical, biological, chemical), and resources development. The second semester discusses municipal, industrial and agricultural water requirements, surface, ground, imported and effluent water resources management; water law; economic, legal, political, and social water resource planning; ecological impact; patterns of use; and survival of man. Mathematical problems are reviewed along with ecological orientation of students.

Page generated in 0.0481 seconds