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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.
491

Distribution of organochlorines between seawater and suspended solids

Cruz, Isabel January 1992 (has links)
An analytical method was developed for the experimental investigations. This included sampling, separation into fractions, clean-up and determination of the organochlorines in suspended solids and seawater. A sampling apparatus was designed and built in our laboratory, capable of sampling seawater up to 28 l, and separating the suspended particles prior to the extraction of the filtered water with organic solvent. The analytical method for the determination of chlorinated biphenyls (CBs) and a large number of organochlorine pesticides in sediments was readily available in our laboratory. In addition, a method for the determination of pentachlorophenol (PCP) in seawater and solids was developed. The complete analytical method for the determination of particulate and dissolved organochlorines in the seawater column, at the ng l<sup>-1</sup>-pg l<sup>-1</sup> level, was validated. Small scale experiments were not able to replicate the environment, therefore, a large scale experiment was undertaken in a Loch in the NW of Scotland. Experimental bags, 60,000 l capacity, were attached to a floatable frame and filled with seawater, then contaminated sewage sludge was dumped on it. A sampling strategy was designed, and a set of samples was obtained to investigate the factors affecting the partitioning, and the kinetics of the partitioning, between suspended solids and seawater. The experimental data from the analysis of the samples were used to propose a simple mathematical model describing the changes in the concentrations of particulate and dissolved organochlorines over the time of the experiment. The mathematical modelling provided values for the desorption rates and the partition coefficients of the nonequilibrium for the individual organochlorines. These calculated parameters were used to elucidate the possible trends related to physico-chemical properties of the organochlorines, and to propose the process affecting the organochlorine-particle interactions: intra-organic matter diffusion.
492

An evaluation of atmospheric dry deposition of selected pollutants to the North Sea

Ottley, Christopher John January 1991 (has links)
No description available.
493

Factors influencing the dry deposition of atmospheric trace particulate species

Vawda, Yasmin January 1990 (has links)
No description available.
494

Studies of ozone deposition

Simmons, Alison J. January 1992 (has links)
No description available.
495

The production of reduced sulphur gases in marine and intertidal sediments and their exchange with the air and sea

Shabbeer, Muhammed Tariq January 1993 (has links)
No description available.
496

Urban air pollution by polycyclic aromatic hydrocarbons in Santiago, Chile : levels, DNA adducts, genotoxicity and CYP1A induction

Adonis, Marta January 1999 (has links)
No description available.
497

Wake dispersion on process plant : enhancing VOC emissions control

Speirs, Lucinda J. January 1998 (has links)
No description available.
498

Effects of sulfuric-nitric acid solutions on mortality and development of Aedes triseriatus larvae and pupae

Fadely, Keith Richard January 1982 (has links)
Larvae of Ae. triseriatus mosquitoes were collected from treeholes on the Ball State University campus. These insects were raised to adulthood under laboratory conditions. Newly hatched larvae were raised in deionized water. One hundred twenty-five of instar 1 mosquitoes (group A) were placed into separate baby food jars containing deionized water. These jars were separated into five groups. The pH of the water in each group was adjusted to 3, 4, 5, 6 and 7 with a 70% to 30% sulfuric-nitric acid solution. Subsequent groups consisting of instar 2, 3 and 4 larvae and pupae (groups B, C, D and E respectively) were exposed to the same experimental treatment as that of group A. The effects of each of these pH levels on mortality and development was observed until the insects reached maturity or died.Larvae in water of pH 3 experienced a higher percentage of mortality than mosquitoes exposed to less acidic solutions. A decrease in mortality with age was observed. Mortality of insects in group A was greater than that of any other group. Mosquitoes in group D experienced the lowest mortality.Variations of developmental time for mosquitoes in pH 3 were probably due to high mortality. Developmental time was similar for all groups. Slight variations between these groups may have been due to natural fluctuations in development. The total average developmental time for Ae. triseriatus mosquitoes of this study was 11.12 days.
499

The advantages of artificial neural network and regression tree based air quality models

Gardner, M. W. January 1999 (has links)
No description available.
500

The significance of indoor:outdoor relationships, and physical and chemical composition in personal exposure to urban particulate matter

Shilton, Vaughan Francis January 2003 (has links)
No description available.

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