Manipulating matter at the nanoscale creates materials endowed with unique optoelectronic and physicochemical attributes. Among the noble metals, the properties of gold in "nano" can be manipulated by varying, their shapes and sizes. Gold nanoparticles find several applications in electronics, medicine and environmental reclamation. Emphasis has been on the “green synthesis” of nanogold to mitigate the hazardous implications stemmed from conventional nanogold synthesis. However, it is not known if the in planta synthesis of nanogold particles could be “green engineered” as well for generating desirable sizes and exotic shapes. In the present study, we used inductively coupled plasma (ICP) analysis to determine the species-specific variability, if any, in uptake of gold across taxonomically diverse plant species (alfalfa, cucumber, red clover, rye grass, sunflower, and oregano). Seedlings of these species were grown in half strength Hoagland’s solution supplemented with 100 ppm potassium tetrachloroaurate (KAuCl4) for 15d under controlled growth room conditions. Significant variations were detected in the ability of different plant species in accumulating gold in the root tissues ranging from 500 ppm (ryegrass) to 2500 ppm (alfalfa). Sunflower and oregano translocated significantly higher levels of gold into their aerial tissues compared to other species. This study thus suggested differential abilities of diverse plant species in uptake of gold by roots and its mobilization to aerial parts. For further elucidation of the effects of different growth variables on in planta synthesis of different shapes and sizes of nanogold particles, alfalfa was selected due to its ability to accumulate large quantities of gold in the root tissues. Further, alfalfa was subjected to KAuCl4 (50 ppm) treatment under variable growth conditions (duration of treatment, pH, temperature and light). Temporal analysis revealed that most of the nanogold particles formed within 6 h of treatment and majority fall within the size range of 10-30 nm. Spherical nanogold particles in the size range of 1-50 nm were detected ubiquitously across different treatments. Interestingly though, a noticeable shift was apparent towards the formation of nanogold particles of exotic shapes in response to specific treatments i.e., pH 3.8 (triangular), pH 7.8 (hexagonal), 15°C (rectangular). This study thus provides empirical evidence towards in planta “green engineering” of nanogold particles of exotic shapes and variable sizes. Efforts are now underway to decipher the mechanistic details governing the acquisition, synthesis and mobilization of nanogold particles in a model plant system. Furthermore, testing the efficacy of alternative non-lignified systems (callus and in vitro germinated pollen tubes) for nanogold particle production is of great interest in that in may be conducive for the extraction of nanogold particles.

In Taiwan, swine wastewater has become one of the major causes of the deterioration of surface water quality. To minimize the operational and maintenance cost of the conventional wastewater treatment utilities, less expensive natural treatment systems (e.g., aquatic plant treatment system) have been proposed to enhance the efficacy of existing three-stage treatment system (solid separation followed by anaerobic and aerobic treatment). Using the natural treatment system is an appropriate technology for treating livestock wastewater in tropical or subtropical regions or developing countries because it is inexpensive, easily maintained, and has environmentally friendly and sustainable characteristics. The main objectives of this study were to (1) examine the efficacy and capacity of using aquatic plant treatment system to polish the treated wastewater to meet the discharge standards in Taiwan (COD = 600 mg/L, BOD = 80 mg/L, and SS = 150 mg/L), (2) evaluate the potential of reusing the treated wastewater, (3) evaluate the feasibility of replacing the aerobic treatment process contained in the three-stage system with the aquatic plant system, and (4) improve the efficiency of sludge (obtained from the three-stage treatment system) composting process. In this study, a hog farm was selected as the case study site. An aquatic plant unit [13.5 (L) ¡Ñ 4 (W) ¡Ñ 3 (D)] planted with Eichhornia crassipes (water hyacinth) was placed after the aerobic system for wastewater polishment. Influent and effluent sa mples from each unit were collected and analyzed for water quality parameters including chemical oxygen demand (COD), biochemical oxygen demand (BOD), and suspended solids (SS). Water samples were collected monthly during the 15-month investigation period. Results show that the averaged COD, BOD, and SS concentrations were approximately 708, 83, and 123 mg/L, respectively after the three-stage treatment scheme. The observed COD, BOD, and SS concentrations dropped to 518, 56, and 48 mg/L, respectively which could meet the discharge standards. Thus, the aquatic plant treatment system played an important role in meeting the discharge standards for swine wastewater. More than 99% of all pollutants were removed by the three-stage system followed by the aquatic plant system. The effluent from the treatment system has been used for hog farm cleaning. Thus, the aquatic plant system has the potential to be applied as the final polishment process to enhance the treatment efficacy of swine wastewater. Results also show that it is feasible to replace the aerobic treatment process with the aquatic plant system from the cost and regulation compliance point of view. Results from the composting study show that rice straws could enhance the activity of microorganisms and also cause the increase the quantity of potassium in the compost pile. Moreover, mixing the water hyacinth in the compost pile could increase the quantity of nitrogen and phosphorous. Results also reveal that using ceramic bioballs as the filling materials could minimize the composting time due to the increase of permeability in the piles.

Ce travail porte sur le comportement du Ra au sein d’un écosystème forestier (Montiers, Meuse). Il s’appuie sur la mesure de plusieurs traceurs isotopiques (déséquilibres radioactifs, rapports 228Ra/226Ra et 87Sr/86Sr) dans les différents compartiments du système eau-sol-plante. Les objectifs étaient : 1) d’étudier la mobilité du Ra et ses ascendants radioactifs entre les fractions minérales séparées d’un profil de sol, 2) d’évaluer le transfert du Ra vers les compartiments eau-plante de l’écosystème, 3) de caractériser le transfert du Ra et son temps de résidence dans la végétation, 4) de réaliser le bilan du cycle biogéochimique du Ra. Ce travail montre une forte redistribution de U, Th et Ra en fonction de leurs affinités respectives avec les différentes fractions minérales du sol. Bien que le Ra soit très fortement associé à la fraction fine (< 2µm) du sol, la végétation (hêtres) semble prélever le Ra des oxydes de fer du sol. Le transfert ultérieur de ce nucléide depuis les racines vers les parties aériennes de l’arbre est moins important que celui des autres alcalino-terreux, aboutissant à un temps de résidence dans la végétation de l’ordre de quelques années (2.6 ± 1.6 ans). Enfin, le cycle biogéochimique du Ra est caractérisé par un flux de dégradation de la litière souterraine plus important que celui lié à la litière de surface, par un apport atmosphérique en Ra négligeable et par un flux d'altération très important, ce dernier ne transitant pas par les solutions de sols gravitaires. Le Ra présent dans ces dernières provient presque exclusivement de la dégradation de la litière. / This work investigates the behaviour of Ra within a forest ecosystem (Montiers, Meuse). It is based on the quantification of several isotopic tracers (U- and Th- series disequilibria, isotopic ratios of 228Ra/226Ra and 87Sr/86Sr) in the different compartments of the water-soil-plant system. The research goals were : 1) to study the mobility of Ra and its radioactive ascendants in the separated mineral fractions of a soil profile, 2) to evaluate the transfer of Ra to the water-plant system, 3) to characterise the transfer of Ra and its residence time onto the vegetation, 4) to realise an account of the biogeochemical cycle of Ra. This work shows a strong redistribution of U, Th and Ra depending on their respective affinities with the different mineral fractions of the soil. Despite being predominantly concentrated in the clay fraction (<2 µm) of the soil, our findings indicate that trees (beeches) mostly extract Ra from the soil’s iron oxides. The subsequent transfer of this nuclide from the roots to the foliage is lesser than that of other alkaline-earth metals, leading to a vegetal residence time on the order of a few years (2.6 ± 1.6 years). Finally, the biogeochemical cycle of Ra is characterised by the degradation flux of fine-roots rather than that of leaves, by a negligible atmospheric input and by a strong weathering rate. Ra presents in the latter originates almost uniquely from litter degradation and does not pass through gravitational soil solutions.

The main objective of this study is to develop a modeling methodology that facilitates incorporating the plant pathway into environmental contamination models recognizing the fact that plants are dynamic entities that regulate their life cycle according to natural and anthropogenic environmental conditions. A modeling framework that incorporates the plant pathway into an integrated water flow and contaminant transport model in terrestrial systems is developed. The modeling framework is aimed to provide a tool to analyze the plant pathway of exposure to contaminants. The model developed using this framework describes the temporal and spatial variation of the contaminant concentration within the plant as it is interacting with the soil and the atmosphere. The first part of the study focuses on the integration of the dynamics of water and contaminant distribution and plant related processes within the vadose zone. A soil-plant system model is developed by coupling soil-water flow, contaminant transport, plant life-cycle, and plant pathway models. The outcome unifies single media continuous models with multimedia compartmental models in a flexible framework. The coupling of the models was established at multiple interfaces and at different levels of solution steps (i.e. model development phase vs. numerical solution phase). In the second part of the study, the soil-plant system model is extended to cover large spatial areas by describing the environmental system as a collection of soil-plant systems connected through overland flow and transport processes on the ground surface and through lateral interactions in the subsurface. An overland flow model is integrated with the previously coupled model of unsaturated zone soil-water flow and plant life-cycle by solving the flow model equations simultaneously within a single global matrix structure. An overland / subsurface interaction algorithm is developed to handle the ground surface conditions. The simultaneous solution, single-matrix approach is also adopted when integrating the overland transport model with the previously coupled models of vadose zone transport and plant pathway. The model developed is applied to various environmental contamination scenarios where the effect of the presence of plants on the contaminant migration within environmental systems is investigated.

The thesis is focused on multiparametric diagnostic of generators at the Dukovany nuclear power plant. One generator was chosen for the thesis and it was examined especially from the practical point of view. The thesis describes current state of the issue with focus on noise diagnostics, vibrodiagnostics and electrodiagnostics. The emphasis is on the system approach of the solution. In the practical part an experiment is designed, described and evaluated. Attention is paid to the conclusions of the performed vibrodiagnostics and noise diagnostics. Data sets are evaluated separately and the relationship between the two diagnostic methods is analyzed. Furthermore, the data set from electrodiagnostics is evaluated and dependencies of electrical diagnostic quantities on other quantities are described. Trends in electrical diagnostic quantities are also monitored. Conclusions and recommendations are formulated at the end of the thesis. It is stated that using multiparametric diagnostics to assess the status of generators in power plants is still in its beginning and that the conclusions of the submitted thesis will contribute to the developmnet in this area.