The genetic structure of oyster drill Thais clavigera along the west coast of Taiwan were assayed by starch gel electrophoresis. Factors of locality¡]i.e. Shainsan, Taisi, Budai, Chiku¡^,maturity¡]i.e. mature, immature¡^ and sampling time¡]i.e.1999.7~2000.3, 2000.11¡^ were analyzed to evaluate their effect on drill¡¥s genetic structure . Four of the eleven investigated enzyme loci were polymorphic , i.e. Ark, Lap-1, Lap-2, and Pgm-1. Among the four populations , the mean heterozygosity¡]H¡^and genetic distances¡]D¡^ ranged from 0.100 to 0.129 and from 0.0005 to 0.0029, respectively. Therefore, T. clavigera along the west coast of Taiwan belongs to the same population. However, differentiation among populations still existed which was contributed by Ark locus. According to the degree of differentiation, the four populations were ranked as Shainsan¡BBudai¡BTaisi and Chiku . A similar trend was also observed in the four populations, as the drill size increased, the mean heterozygosity and the heterozygosity of Ark locus increased. Sampling time had no significant effect on genetic structure of populations. It is suggested that environmental factors¡]e.g. environmental quality and topography¡^and drill¡¦s reproductive ecology may be important in determining the genetic structure of populations.

Abstract ¡@¡@The present study was undertaken to understand the accumulation of PCBs in the marine environment of Taiwan. Samples including oyster drills, oysters, sediments and seawater were collected from the West coast of Taiwan and analyzed by GC/ECD and GC/MS. ¡@¡@The concentration of PCBs in sediments was 31.05¡ã406.38 pg/g dry wt with the highest one at Tong-Kung. The PCBs in cultural oysters from Tong-Kung was 3.80 pg/g wet wt. Concentrations of PCBs in wild oysters from Tai-Si, Chi-Ku, and Pu-Dai were 123.57 pg/g wet wt, 2.93 pg/g wet wt, and 2.08 pg/g wet wt, respectively. The concentrations of PCBs in snails were in the range of 78.24 to 796.96 pg/g wet wt with the highest one from Tong-Kung. A positive correlations between the concentrations of PCBs in seawater and sediment (r=0.78; p<0.01) and in oysters and snails were also observed(r=0.79; p<0.01). The bioaccumulation of PCBs from seawater to oysters was about 72 times, and the biomagnification of PCBs from oysters to snails was 10 times.

Thesis (M.S. in Computer Science and M.S. in Modeling, Virtual Environments and Simulation (MOVES))--Naval Postgraduate School, September 2003. / Thesis advisor(s): Rudolph Darken, Joseph Sullivan. Includes bibliographical references (p. 51). Also available online.

This dissertation implements three-dimensional numerical simulation models to interpret formation-tester measurements acquired at arbitrary angles of wellbore deviation. Simulations include the dynamic effects of mud-filtrate invasion and multi-phase flow. Likewise, they explicitly consider the asymmetric spatial distribution of water-base and oil-base mud filtrate in the near-wellbore region due to the interplay of viscous, gravity, and capillary forces. Specific problems considered by the dissertation are: (a) estimation of permeability from formation-tester measurements (pressure and fractional flow) affected by multi-phase flow and mud-filtrate invasion, (b) quantification of the spatial zone of response of transient measurements of pressure and fractional flow rate, (c) prediction of fluid-cleanup times during sampling operations in vertical and deviated wells, (d) joint inversion of formation-tester and resistivity measurements to estimate initial water saturation and permeability of multi-layer models, and (e) estimation of saturation-dependent relative permeability and capillary pressure using selective measurement weighting and Design-of-Experiment (DoE) methods to secure a reliable initial guess for nonlinear inversion. Using realistic tool and formation configurations, field measurements validate the reliability of the proposed methods. In one example, multi-layer rock formations are modeled using electrofacies derived from nuclear magnetic resonance logs, thereby reducing the number of unknown layer permeability values from 22 to 6. In the same example, non-uniqueness in the estimation of permeability is reduced with the quantitative integration of resistivity and formation-tester measurements. A second field example undertakes the estimation of permeability by history matching both pressure and gas-oil ratio (GOR) measurements acquired with a focused-sampling probe in a 27° deviated well. Because the latter measurements are affected by partial miscibility between oil-base mud and in-situ oil, Equation-of-State (EOS) simulations are used to account for variations of fluid viscosity, fluid compressibility, fluid density, and GOR during the processes of invasion and fluid pumpout. Results indicate that gravity-segregation and capillary-pressure effects become significant with increasing angles of wellbore deviation. If not accounted for, such effects could substantially degrade the estimation of permeability. Synthetic and field examples confirm that standard formation-tester interpretation techniques based on single-phase analytical solutions lead to biased estimations of permeability, especially in deviated wells or when complete fluid cleanup is not achieved during sampling. In addition, it is found that gravity-segregated invaded formations strongly affect predictions of fluid sampling time. Reliable and accurate estimations of petrophysical properties are only possible when both the angle of wellbore deviation and the process of mud-filtrate invasion are included in the interpretation methods. / text

The core-logger has been designed for the high-resolution radiometric analysis of soil cores using multiple detectors. This device allows for the automation of the measuring process and eliminates the need to dissect the cores. The design is aimed at measuring soil-cores with a 10cm radius and a length of 1m and allows for up to 4 detectors to be mounted on the measuring platform. Currently a combination of Bismuth-German.te (BGO) and C.esiwn-Iodide (CsI) detectors are used. The core logger required a good spatial resolution of - 1 cm. This has been difficult to obtain and has required extensive investigation. The shielding configurations were varied and the effect of background radiation was looked at in detail to determine an optimal construction. A secondary objective has been the complete measurement of a single core in 24 hours. This has also been difficult to achieve because the low activity of natural radiation in the core samples needs longer measuring times. The BGO detectors were used as a more efficient detector (than, e.g. CsI) which helped to reduce the required measuring time. Measured spectra have been analysed to determine the activity concentrations of the specific radionuclides of interest: 232Th, 238U, 40K and 137Cs. These activity profiles of the measured cores provide information that can then be used to radiometrically fingerprint the sample to determine soil characteristics such as grain size and mineral content. However, because the actual resolution of the system ( ~3cm) is greater than the typical core slice (~ 2cm), the radiometric information in a specific core-slice contains contributions from its adjacent slices. This folding or convolution of the measured spectra can be undone using a deconvolution method. which was examined and commented on. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

No description available.

The ability of starch to impart functions including fluid-loss control, cuttings transport, and rheological characteristics to water-based drilling fluids has led to its widespread use in the oil industry. The filter cake deposited by these drilling fluids often employs sized solid particles and starch to inhibit fluid loss into the formation. This inherently causes damage to the formation by impairing the permeability and must be removed before production. An alpha-amylase enzyme treatment was found to provide an effective approach to degrading starch in filter cake. In this work, an alpha-amylase enzyme treatment was analyzed by determining the extent of degradation of starch in filter cake using the iodine test, identifying degradants using high performance liquid chromatography, spectrophotometrically monitoring the concentration of enzyme, and measuring the cleanup efficiency of the enzyme treatment using a static filter press apparatus. The alpha-amylase enzyme used in this study was found to have a molecular weight under 30,000. The activity of the alpha-amylase enzyme was found to be sensitive to pH and temperature. The alpha-amylase enzyme was found to denature at temperatures above 165 degrees F and reversibly deactivate at pH below 4. Optimal conditions for alpha-amylase activity were found to be 150 degrees F and pH 6.5. The enzyme treatment works by hydrolyzing the interior glycosidic bonds of amylose and amylopectin residues of starch, creating soluble poly- and oligosaccharides and glucose. The enzyme treatment did not dissolve the calcium carbonate sized solids and a 5 wt. % hydrochloric acid postflush was necessary. The cleanup efficiency of the enzyme at pH 6.5 and room temperature treatment in conjunction with the postflush in a static test was 73% at 10% v/v concentration. Degradants resulting from alpha-amylase were identified chromatographically. Enzyme concentration remained steady prior to and after treatment.

Diabetes mellitus is a systemic condition that remains undiagnosed in a large portion of the population, which presents potential challenges for implant-based rehabilitation. Currently, the effects of diabetes on bone healing are not fully understood. Thus prior to employing a model of diabetes in studies of peri-implant healing, it was important to investigate the temporal effects of hyperglycemia on bone healing. Bone healing of femoral drill-defects was compared between streptozotocin-induced hyperglycemic (DB) and normoglycemic (NDC) rats at 5, 10, 15, and 30 days P.O. Quantitative assessment of bone samples using μCT demonstrated a delay in bone formation occurring up to 10 days in DB animals. Histological assessment confirmed these quantitative findings. Additionally, fluorescently stained bone samples indicated possible defects in mineralization of bone in DB group. In summary hyperglycemia affects bone healing at the early stages of bone formation, concurrent with the osteoconduction phase of bone healing.

Diabetes mellitus is a systemic condition that remains undiagnosed in a large portion of the population, which presents potential challenges for implant-based rehabilitation. Currently, the effects of diabetes on bone healing are not fully understood. Thus prior to employing a model of diabetes in studies of peri-implant healing, it was important to investigate the temporal effects of hyperglycemia on bone healing. Bone healing of femoral drill-defects was compared between streptozotocin-induced hyperglycemic (DB) and normoglycemic (NDC) rats at 5, 10, 15, and 30 days P.O. Quantitative assessment of bone samples using μCT demonstrated a delay in bone formation occurring up to 10 days in DB animals. Histological assessment confirmed these quantitative findings. Additionally, fluorescently stained bone samples indicated possible defects in mineralization of bone in DB group. In summary hyperglycemia affects bone healing at the early stages of bone formation, concurrent with the osteoconduction phase of bone healing.

Research was conducted into using supercritical fluid extraction (SFE) for removing hydrocarbons from drill cuttings slurries, which will be used in a pilot-scale continuous SFE system currently under development. A laboratory-scale batch SFE system employing supercritical carbon dioxide (CO2) was used in this research. Based on the measured hydrocarbon solubility and apparent hydrocarbon solubility in supercritical CO2, conditions of 14.5 MPa and 40oC were selected for SFE treatment. The slurries require a minimum water to drill cuttings ratio of 1:1 (mass basis) to be free-flowing and therefore suitable for treatment in a continuous system. Water in the slurries leads to lower hydrocarbon extraction efficiencies during SFE treatment compared to the treatment of drill cuttings without slurrying. However, effective mixing and introduction of the supercritical CO2 at the bottom of the extraction vessel resulted in treated slurries containing less than 1% hydrocarbons (dry mass basis). / Environmental Engineering