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Thin layered systems can be considered as a solution to the repair and protection of concrete structures. This subject was studied in the current investigation. Some common uses of these systems include protection, upgrading and rehabilitation of the floor slabs,restoration of appearance of the structures, impermeability, skid resistance, wear resistance, and protection of the reinforcing steel of concrete structures against atmospheric or chemical attack. However it can be said that protection, upgrading and rehabilitation of floor slabs are the main uses for the design of modem thin layered systems. For example a thin layer of a polymer concrete with a thickness of less than 3 nun can resist a very highly concentrated load resulting from a steel wheel rolling load of 5000 N without any sign of defect. Thin layer systems therefore include traditional screeds, externally bonded steel plates, plasters and coatings as well as the more recent hi - tech. systems. Like any other structure, a thin layered system may break down as the result of many causes. Among other types of failures, delamination defect is the most common mode of failure and particularly relevant to a thin layered system. This phenomenon which mostly occur between the upper layer directly subjectedto the load and the subsequent layer, is due to debonding or slippage at the interface of the two layers. A delamination may occur at the interface of a thin layered system even without any sign of failure in other parts of the structure. Steel wheeled trolleys and fork - lift trucks are among the most anticipated types of loading and causes of failures in the thin layered systems. Different combinations of thin layered systems were prepared using some special flooring materials, both in small and large scales. Despite the lack of any standard test, the action of a steel wheel rolling load on the ready made and purpose made specimens of thin layered systems was well simulated using the Steel Wheel Rolling Load Rig. The NUROLF, Newcastle University Rolling Load Facility, was also used for simulating the action of a tyred vehicle wheel rolling load on the thin layered systems of large scale. Some simple ways for detecting any possible delamination at the interface of the thin layered systems were examined. In addition to the available material characteristics tests, a relatively new simple shear box test was proposed for defming the relationship between normal stress and the correspondings hear strength for each combination of the materials at each age of the test. The results were then used as the basis for the subsequent structural analysis. The structural analysis of the systems was carried out for both of the experiments using the finite element method and the interface technique. In spite of the simplifications made in the solution, the analytical results were consistent with the experimental results to a considerable extent. Based on the results of this investigation, a relatively constitutive procedure was concluded for predicting the behaviour of a thin layered system under the action of a wheel rolling load with regard to the delamination defect.

An industrial soil collected from a recycling factory was contaminated by DEHP and spilled diesel. The soils were divided into two batches for off-site ex situ bioremediation by SMC. This industrial soil was contaminated with 5.4-6.9 g/kg total petroleum hydrocarbons (TPH), 14.5--19.0 g/kg oil and grease and 95-99 mg/kg DEHP. The removal by 3% SMC amendment applied twice accounted for 56-64%, 31--33% and 51--54% disappearance of the TPH, oil and grease and DEHP contaminants, respectively. Beside chemical analysis, six bacteria and six fungi were inoculated into the sterilized soil samples for ecotoxicity tests. The original soil samples containing residual oil and DEHP contents were found to be more toxic than the SMC-treated soil. Thus SMC simultaneously degrades organic pollutants and reduces toxicity in less than a month. / An underground water sample contaminated with dibutyl phthalate (DBP, 127.5+/-20.7 mu1/1) and DEHP (67.0+/-7.7 mu1/1) was tested. One percent SMC could remove 94.2+/-3.6% and 100% for DBP and DEHP, respectively, within 1 h at room temperature. DBP and DEHP were degraded completely by SMCE except 0.2% SMCE for DBP after 24-h treatment. SMC had higher removal efficiencies than SMCE, because SMC had an integrated system of biosorption and biodegradation to remove DBP and DEHP. The sorption kinetics of DBP and DEHP by SMC could be described by the Freundlich monolayer model. Even after eight cycles of the sorption-desorption of DEHP SMC maintained the 100% removal efficiency. Thus SMC is a good biosorbent for DEHP. / Besides, DEHP-contaminated sediment was collected from Kai Tak Approach Channel, Kowloon. This sediment contained 44.4-128.0 mg/kg DEHP and heavy metals 21.3-23.4 mg/kg Cd, 24.9-43.5 mg/kg Ni, 128.5-198.5 mg/kg Pb, 144.6-329.2 mg/kg Zn and 164.5-230.0 mg/kg Cu, and bore an unpleasant sewer smell. SMC and SMCE as strong oxidizing agents could decrease the S content of sediment significantly as well as calcium nitrate, and consequently lowered the evolution of nuisance gas hydrogen sulfide. With the treatment of the optimized combination of 2.25% SMCE and 0.25% nitrate, the malodor could be removed completely and the contents of H2S and NH3 in the air were decreased significantly. For the degradation of organic pollutants, the target pollutant DEHP showed a sharp decrease in the first week in the time effect experiment after the treatment with the combination of 2.25% SMCE and 0.25% nitrate, while the decrease of DEHP slowed down in the second week. The results may be attributed to the immediate degradation of DEHP by enzymes in SMCE. When raw sediment and nitrate-treated sediment were bioremediated with SMCE, larger fluctuation in DEHP removal was observed with the nitrate-treated sediment. It supports that nitrate and SMCE would act in optimum at a certain combination. The effect on mobilization of sediment heavy metals by SMC or SMCE was also examined. Although some laboratory results suggested reduction of copper and lead, other results using different environmental samples of the sediment did not reproduce the results. Further investigation is needed. / Plasticizers are additives used in the manufacture of plastics, and high residual plasticizer levels are encountered in the environment. Bis(2-ethylhexyl) phthalate (DEHP), being the most common plasticizer, is a suspected human carcinogen and an endocrine disruptor. Therefore, DEHP-contaminated soil, sediment and water samples were collected, and the bioremediation capacities of the spent compost of mushroom Pleurotus pulmonarius (SMC) were determined. / This study reveals the potential in applying SMC of P. pulmonarius in bioremediation of DEHP from the soil, sediment and water environments. More investigation and field studies would be appropriate for developing spent P. pulmonarius compost in environmental cleanup. / Using artificially spiked garden soil with DEHP and ultra-low sulphur diesel, the removal efficiencies of SMC were 41.7+/-9.8% and 36.1+/-8.4% for TP11 and DEHP, respectively. SMCE which contained the water-soluble nutrients, SMC enzymes and micro-organisms had about half removal efficiency of SMC on the same pollutant. The enriched SMC microorganisms also showed biodegradation of DEHP and diesel, so did the filtrate containing enzymes and nutrients of SMC. Thus SMC acted in multiple ways in bioremediation of DEHP: biostimulation and bioaugmentation. Besides, the immobilized lignolytic enzymes of the mushroom P. pulmonarius played a major role in biodegradation. / Gao, Ting. / "October 2009." / Adviser: S.W. Chiu. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 204-237). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The pharmacokinetics, oral bioavailability, cerebrovascular permeability and biotransformation of the neurotoxic plasticiser n-butylbenzenesulfonamide (NBBS) were studied in order that the human health risk due to environmental exposure to NBBS could be evaluated. The pharmacokinetics of NBBS was determined in Wistar rats, following intravenous administration of the isotopomer [13C6] NBBS (1 mg/kg in 0.9% saline). [13C6] NBBS is cleared from plasma at a rate of 5 ml/min by the liver. The plasticiser has a short distribution phase (t1/2 of 47 seconds) and a long terminal phase (t1/2 of 17 hours). Plasma [13C6] NBBS concentrations, 24 hours after administration, represented 0.04% of the administered dose. These data indicated rapid uptake into tissue, which was subsequently confirmed by monitoring tissue concentrations of [13C6] NBBS for upto 8 hours following administration. [13C6] NBBS was not accumulated by any of the tissues studied (brain, liver, kidney, muscle and adipose tissue). Oral bioavailability was determined by simultaneously administering native NBBS orally and [13C6] NBBS intravenously to Wistar rats. The plasticiser was found to be absorbed erratically and subject to first pass metabolism. Plasma concentrations of orally administered NBBS fluctuated over the duration of the experiment. Furthermore, limitations posed by the assay resulted in truncated oral curves. These factors precluded estimation of areas under the oral NBBS curves to infinity and partial area ratios were instead used to calculate absolute bioavailability (mean of 19%). Cerebrovascular permeability of NBBS was determined with [13C6] NBBS, in Sprague-Dawley rats, using the in-situ brain perfusion technique of Takasato et al. (1984). The uptake of [13C6] NBBS into brain was very rapid and flow limited. Assuming an average cerebral perfusion fluid flow rate of 0.11 ml/s/g, the calculated single pass extraction value for [13C6] NBBS is 99.9% with a Kin of 0.11 ml/s/g. This is in close agreement with experimental values for the 15 second saline perfusions (extraction = 98% - 125% and Kin = 0.108 - 0.137). Differences in regional brain distribution of the plasticiser were not found. In-vitro biotransformation studies revealed one phase I metabolite in incubates of NBBS containing human, rabbit and rat post-mitochondrial supernatant (S9 fraction). This metabolite is 2-hydroxy-n-butylbenzenesulfonamide (NBBS-OH hydroxylated in the Based on these data, environmental exposure to NBBS does not pose a significant human health risk.

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Thesis (Ph.D.) -- University of Rhode Island, 2007 / Typescript. Includes bibliographical references (leaves 178-184).

M.Sc. (Chemistry) / Please refer to full text to view abstract