• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 34
  • 34
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 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

Linking the neuropeptide annetocin with reproductive success of the earthworm Eisenia fetida in two natural soils amended with the wood preservatives chromated copper arsenate (CCA) and alkaline copper quaternary (ACQ)

Leduc, Frédéric January 2004 (has links)
Chromated copper arsenate (CCA), type C, was largely used as a wood preservative due to its exceptional fungicidal and insecticidal properties. Although this treatment was prohibited for residential purposes in Canada and in the United-States of America, concerns about CCA-treated wood focus on the possible threat on human health and the contamination of the environment, through the leaching of metals from existing structures. The objectives of this thesis are (1) to assess the effects of metals leached from CCA- and ACQ-treated wood on the survival, the growth and the reproductive success of the earthworm Eisenia fetida (Annelida, Oligochaeta), and (2) to evaluate if annetocin, a neuropeptide linked to reproduction, could be used as a biomarker of ecotoxicological responses of the worm E. fetida when exposed to metals from the CCA treatment. Ecotoxicological tests with E. fetida were carried out according to the protocol ISO-11268-2. (Abstract shortened by UMI.)
12

Copper compounds for durable composites : effects on material properties /

Vidrine, Cheney L. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 86-95). Also available on the World Wide Web.
13

Linking the neuropeptide annetocin with reproductive success of the earthworm Eisenia fetida in two natural soils amended with the wood preservatives chromated copper arsenate (CCA) and alkaline copper quaternary (ACQ)

Leduc, Frédéric January 2004 (has links)
No description available.
14

Preserving Decayed Wood Samples for Tree-Ring Measurement

Krusic, Paul J., Jr., Hornbeck, James W. January 1989 (has links)
Wood disks in various states of decay can be inexpensively preserved and prepared for accurate crossdating and precise tree-ring measurement by impregnation with commercial wood glue. The technique does not affect the dimensions or physiological features of samples preserved in this manner. Dead red spruce trees on Mt. Washington, New Hampshire, remain available for dendrochronological examination as long as 29 years after their last year of stem growth.
15

The environmental effects of CCA-treated wood use in the sea

Albuquerque, Ruth Margaret January 1998 (has links)
No description available.
16

Mechanical and physical properties of preservative-treated strandboard

Kirkpatrick, John Warren, January 2005 (has links)
Thesis (M.S.) -- Mississippi State University. Department of Forest Products. / Title from title screen. Includes bibliographical references.
17

Essential oil treatment of VTC wood

Scouse, Adam A. 13 September 2012 (has links)
Western juniper and cinnamon essential oils were combined with ethanol at 2.5, 5, and 10% concentrations by weight and applied to hybrid poplar (Populus trichocarpa x P. deltoids) veneers by vacuum soaking to produce a naturally durable wood veneer with increased mechanical properties for use in structural composites. Half of these veneers were then modified using viscoelastic thermal compression to increase veneer density and modulus of elasticity. Following densification, unprocessed and VTC processed veneers receiving an essential oil treatment were subjected to an AWPA E21-06 Formosan termite exposure test, AWPA E24-06 mold box test, and brown rot (Gloeophyllum trabeum) decay bending test. While VTC processing drastically reduced the abundance of chemical components inherent within essential oil treatments, veneer specimens without VTC processing showed increased durability. A 10% juniper oil treatment drastically reduced Formosan termite attack on hybrid poplar veneers while a 10% cinnamon oil treatment significantly reduced mold growth. Timbor��, an industrial powdered borate treatment, withstood VTC processing and inhibited Formosan termite attack and mold growth. Tests to evaluate the effectiveness of essential oil treatments against brown rot were unsuccessful. Results suggest that incorporating a disodium octaborate tetrahydrate (DOT) treatment prior to VTC processing could help improve VTC wood durability. / Graduation date: 2013
18

Preserving our natural heritage - timber

Cokley, Keith V. Unknown Date (has links)
No description available.
19

Preserving our natural heritage - timber

Cokley, Keith V. Unknown Date (has links)
No description available.
20

Qualidade ambiental da sub-bacia do Baixo Taquari influenciada por sítio contaminado em processo de remediação

Gameiro, Paula Hauber January 2015 (has links)
A contaminação do solo é uma das fontes pela qual os contaminantes são escoados para os ecossistemas aquáticos, afetando a qualidade dos sedimentos. Neste compartimento alguns compostos são capazes de bioacumular e interferir nos fluxos de energia e de nutrientes da cadeia biológica, gerando efeitos agudos, crônicos e genotóxicos para as comunidades que vivem ou entram em contato com este local. A região de estudo está localizada em área às margens do rio Taquari, no município de Triunfo, RS, próxima a um sítio com solo contaminado por preservantes de madeira, com passivo ambiental identificado (creosoto, pentaclorofenol e a hidrossal CCA). Esta área foi submetida à primeira fase do processo de intervenção para retirada das principais fontes ativas. Em estudos anteriores foi definido o provável escoamento de contaminantes para o rio a partir do solo contaminado. Para avaliar a qualidade dos sedimentos, nas diferentes fases de intervenção da área, foi utilizado o ensaio Salmonella/microssoma, para avaliar mutagênese, além da dosagem de HPAs nos extratos orgânicos de sedimentos. Foram testados quatro áreas de coleta, identificadas pela distância em Km a partir da foz, abrangendo local a montante do sítio, Ta032, em frente, Ta010, e a jusante, Ta006 e Ta004. As coletas foram nas fases, antes (inverno e verão), durante (verão) e após (verão) o processo de intervenção. A mutagênese foi avaliada através de linhagens que medem erro no quadro de leitura (TA98 e Ta97a) e substituição de pares de bases (TA100), na presença e ausência de S9mix (±S9) em extratos de compostos moderadamente polares de sedimento. Os resultados indicaram presença de pró-mutágenos em todas as amostragens na área Ta010, sendo mais elevada na anterior à intervenção (verão) para TA100+S9 (1672 rev/g) decrescendo durante e após este processo. Foram também observados valores constantes de HPAs totais e presença das espécies com potencial cancerígeno nos diferentes períodos avaliados. O local Ta006, após a intervenção, foi o que mostrou mutagênese mais alta (764 rev/g), sendo que as espécies consideradas cancerígenas foram detectadas em maiores concentrações, em especial o benzo(b+k) fluoranteno, que também esteve elevado, neste período, em Ta004. Presença de mutagênese e HPAs em arroio interno ao sítio, a montante de Ta010, marcaram uma das rotas de dispersão dos contaminantes. A presença de contaminação em frente ao sítio, após a intervenção, pode estar relacionada com a técnica escolhida para retirada das fontes ativas, contribuindo na presença de contaminantes a jusante deste rio, Ta006 e Ta004. / Soil contamination is one fo the sources of contaminant runoff into acquatic system, affecting sediment quality. In this compartment some compounds can bioaccumulate and interfere in the energy and nutrient flux of the biological chain with acute, chronic and genotoxic effects on the communities who live there or have contact with this place. The region studied is located on the area on the banks of Taquari river, in the municipality of Triunfo, RS, close to a site with soil contaminated by wood preservatives and identified environmental liabilities (creosote, pentachlorophenol and hydrosalt CCA). This area was submitted to the first stage of the intervention process to remove the main active sources. Previous studies defined the probable runoff of contaminants into river from contaminated soil. In order to evaluate the sediment quality in the different phases of intervention in the area, the Salmonella/microsome assay was used to evaluate mutagenesis, besides the dosage of PAHs in the sediment organic extracts. Four collection areas were tested, identified by the distance in km from the mouth, covering a location upstream from the site, Ta032, in front, Ta010, and downstream, Ta006 and 004. The collections were performed in the phases, before (winter and summer), during (summer) and after (summer) the intervention process. Mutagenesis was evaluated using frameshift (TA98 and Ta97a) and base pair substitution (TA100) strains in the presence and absence of S9mix (±S9), in extracts of moderately polar sediment compounds. The results indicate the presence of promutagens in all samplings in the Ta010 area, and it is higher before the intervention (summer) for TA100+S9 (1672 rev/g) decreasing during and after this process. Constant values of total PAHs and presence of species with a carcinogenic potential were also observed in the different periods evaluated. Site Ta006, after intervention, showed the highest mutagenesis (764 rev/g), and the species considered carcinogenic were detected at higher concentrations, especially benzo(b+k) fluoranthene, which was also high during this period at Ta004. The presence of mutagenesis and PAHs in a stream inside the site, upstream from Ta010 marks one of the contaminant dispersion routes. The presence of contamination in front of the site after intervention may be related to the technique chosen to remove the active sources, contributing to the presence of contaminants downstream of this river, Ta006 and Ta004.

Page generated in 0.0704 seconds