No description available.

No description available.

The aim of this study was to apply a variety of investigative methods to identify the causes of elevated concentrations of nitrate reported in an unconfined aquifer around the township of Coonawarra in the South East region of South Australia. For nearly 30 years elevated nitrate concentrations have been of concern to Government Departments, however the source of these elevated nitrate concentrations remained unknown. Examination of an extensive historical water quality dataset for the study area identified that while nitrate concentrations were elevated during the late 1970s – early 1980s, they have declined since this time. The study demonstrates a variety of inherent biases that can exist within nitrate groundwater datasets, and presents methods that can be used for determining temporal trends in concentration that minimise the impacts of these characteristics. The quantification and spatial variability of diffuse recharge was investigated using groundwater tritium concentrations measured in the aquifer during the late 1970s. The modelling produced estimated recharge rates that were generally below those now adopted for the study area, and the methodology may not be appropriate in areas where high irrigation rates are occurring. The assessment of the variability of recharge illustrates that the high recharge areas corresponded to the previously identified areas of higher nitrate concentrations in groundwater. This correlation was further investigated statistically, and used a dual isotopic technique that applied the natural variability of nitrogen and oxygen isotopes (of nitrate) to source determination. The statistical approach was only able to explain 39% of the variability observed in groundwater nitrate concentrations using field observations. This approach indicated that there was a significant spatial relationship between bores located in close proximity to septic tanks and elevated nitrate concentrations in groundwater. The applications of the dual nitrate isotopic method further demonstrated that nitrate in the groundwater is from multiple sources, with septic tanks being a probable source of nitrate. This isotopic method is shown to be effective in source determination, with the results comparing well to literature and field observations. Modelling of diffuse inputs from the main landuse types supports the conclusion that the elevated nitrate levels are most likely due to localised sources. It is concluded that while high nitrate concentrations have existed within the Coonawarra area, the data interpretation methods previously used to report the ‘plume’ of nitrate contamination have over-estimated the extent of nitrate in groundwater. The elevated nitrate concentrations in the groundwater are primarily the result of anthropogenic sources (e.g. septic tanks) and natural sources (e.g. the mineralisation of soil organic nitrogen).

No description available.

We report results for the development of a flow-through integrated cavity absorption meter (ICAM.) Absorption measurements have been made with 2% or less change in the signal in the presence of up to 10 m-1 of scattering in the medium. The operating range of the ICAM ranges from 0.004 m-1 to over 40 m-1 of absorption. This range allows one to use a single instrument to measure the absorption from sediment laden rivers out to the cleanest of ocean waters. Further, the ICAM signal has been shown to be independent of the flow rate and turbulence in the medium. In addition we report the development of a diffuse reflector which, to our best knowledge, has the highest measured diffuse reflectivity of 0.998 at 532 nm and 0.996 at 266 nm. We also show that the average distance a photon travels between successive reflections in an integrating cavity of arbitrary shape is four times the volume divided by the surface area, 4 V/S. Further, for a cavity which is formed by planes tangent to an inscribed sphere and which maintains a homogeneous and isotropic field, the average distance traveled by a photon between successive reflections is equal to 4 V/S of the inscribed sphere. Thus, each cavity has the same ratio of V/S as the inscribed sphere. These advances lead to an increase in the sensitivity of absorption spectroscopy. The sensitivity approaches that of cavity ring down spectroscopy (CARS), without the adverse scattering effects traditionally associated with CARS.

Cancer is a class of diseases in which a group of cells grow uncontrollably, destroy surrounding tissue and eventually spread to other parts of the body, often leading to death. According to the American Cancer Society cancer causes accounts for 13% of all deaths. Much of the time cancer can be treated if diagnosed early. Considerable study is currently being undertaken to investigate tissue properties and their use in detecting cancer at an early stage through non invasive and non surgical methods. Oblique Incidence Diffuse Reflectance Spectrometry (OIDRS) is one such method. This thesis reports the design, fabrication and testing of a new miniaturized optical sensor probe with "side viewing" capability for oblique incidence diffuse reflectance spectrometry. The sensor probe consists of a lithographically patterned polymer waveguides chip and three micromachined positioning substrates and source/collection fibers to achieve 45 degree light incidence and collection of spatially resolved diffuse reflectance. The probe was tested at the Mayo Clinic in Rochester Minnesota. The test results show that the probe is capable of collecting data which can be analyzed to select image features to differentiate the cancerous tissue from non cancerous tissue. Using these probes, diffuse reflectance of human esophageal surface has been successfully measured for differentiation of cancerous tissues from normal ones.

In this experimental, we use ECAE with route BC to produce the ultrafine-grain Al and use different annealing temperature to get grain size at 0.4

The study of the bioeffects of ultrasound and their etiology is of fundamental importance as a part of basic biophysics. In general, the most fruitful approach to the study of bioeffects of physical agents is the mechanistic one. The ultrasonic mechanisms include the mechanical effect, convective effect, cavitation effect, and thermal effect. In this research, the test skin was radiated the ultrasound using the medical equipment and analyzed the permeation of skin. However, it is not sufficiently to analyze the quantitative of the sonophoresis by the medical equipment setup. To solve the above-mentioned problem, the oscillation of the stratum corneum in response to the ultrasound radiation is simulated using Rayleigh-Plesset¡¦s bubble activation theory. To calculate the resonance frequency domain of bubbles attached of pig skin which is around 15 to 36 kHz that called low frequency and it caused gas body activation on test skin. We choose 20 kHz in the resonance frequency domain to compared with 10, 60 kHz as non-resonance frequency. 1.9 and 13.6 mW/cm2 of the sound intensity which are respectively lower and higher than cavitation threshold intensity are used. The result of low frequency sonophoresis presented that high permeation rate is caused by resonance frequency 20 kHz. And according to the experiment, it is also proved that the experiment of low frequency sonophoresis only took 1/160 of the sound intensity and 1/4 of the time for the high frequency sonophoresis. Furthermore, the research examined the uniformity of the sound field, and a wedge is designed to make a diffused field to compare the effect between a uniform one and its contrast. The result presented that the permeating drug with uninformative field is twice the amount of the normal exposure ultrasound field. Based on the above results, the changes of frequency, sound intensity and sound field uniformity, the enhancement effects of the sonophoresis will be achieved.

Abstract Ultrasonic technique is widely used in medical application and food industry; however, much work has focused on harmful biological effects of tissues and cells by ultrasound exposure; only little information is mentioned about the beneficial biological effects of ultrasound. Thus, the objective of this thesis is to observe the beneficial biological activities of Paramecium induced by ultrasound exposure. Since the structure or biophysical will stimulated into the interaction between ultrasound and living matter. When multi-cell creature is exposed by ultrasound, this reaction will lead the biological effect becomes complex. Therefore, a single cell creature is chosen to understand the beneficial biological effects induced by ultrasound exposure. The oscillation of the monad in response to the ultrasound radiation is simulated using Rayleigh-Plesset¡¦s bubble activation theory. The resonance frequency of the unicellular creature is then calculated. The diffuse field theory of Sabine is used to create a uniform sound field for the radiation experiment. The images obtained from a microscope can be analyzed and recorded by a personal computer. The number of cells was counted in the haemacytometer after irradiation. The calculated resonant frequency range of the Paramecium shape is 0.2~0.27 MHz. The relative growth rate of the Paramecium suspensions exposed to ultrasound was about 20% slower than that of unexposed sample. It was found that the phenomenon of inhibition and destruction appeared during irradiation. Also, the growth curve is retarded during the period. The resonance frequency of the Paramecium vacuole is 0.5~1.09 MHz. The maximum relative growth rate was increasing 18% with 1MHz irradiation.

We report results for the development of a flow-through integrated cavity absorption meter (ICAM.) Absorption measurements have been made with 2% or less change in the signal in the presence of up to 10 m-1 of scattering in the medium. The operating range of the ICAM ranges from 0.004 m-1 to over 40 m-1 of absorption. This range allows one to use a single instrument to measure the absorption from sediment laden rivers out to the cleanest of ocean waters. Further, the ICAM signal has been shown to be independent of the flow rate and turbulence in the medium. In addition we report the development of a diffuse reflector which, to our best knowledge, has the highest measured diffuse reflectivity of 0.998 at 532 nm and 0.996 at 266 nm. We also show that the average distance a photon travels between successive reflections in an integrating cavity of arbitrary shape is four times the volume divided by the surface area, 4 V/S. Further, for a cavity which is formed by planes tangent to an inscribed sphere and which maintains a homogeneous and isotropic field, the average distance traveled by a photon between successive reflections is equal to 4 V/S of the inscribed sphere. Thus, each cavity has the same ratio of V/S as the inscribed sphere. These advances lead to an increase in the sensitivity of absorption spectroscopy. The sensitivity approaches that of cavity ring down spectroscopy (CARS), without the adverse scattering effects traditionally associated with CARS.