Water level data at 16 ground water wells and two sea water gauging stations, coupled with barometric measurements in an alluvial plain in the central‐west region of Taiwan, are analyzed using spectral analysis in the time and frequency domains. The semi‐diurnal component from water level station is observed to be the most noticeable signal while the diurnal component is the less distinct signal recorded at the water level stations. Both semidiurnal and diurnal components are coupled with atmospheric pressure measurements. From the atmospheric pressure data, spectral analysis indicates that both the raw and the pressure adjusted water levels are almost in phase and retain the same amplitude in this area. It implies that the effect of pressure variations is not significant for the sea water and ground water level nearby; the astronomical tidal components, as expected, are the main factor causing fluctuation of ocean water and ground water levels in the Choshuihsi alluvial plain.

Bacterial biofilms are highly structured, surface associated bacteria colonies held together by a cell-generated polymer network known as EPS (extracellular polymeric substance). This polymer network assists in adhesion to surfaces and generates spreading forces as colonies grow over time. In the laboratory and in nature, biofilms often grow at the interface between air and an elastic, semi-permeable nutrient source. As this type of biofilm increases in volume, an accommodating compression of its substrate may arise, potentially driven by the osmotic pressure exerted by the EPS against the substrate surface. Here we study Bacillus subtilis biofilm force generation by measuring the magnitude and rate of deformation imposed by colonies against the agar-nutrient slabs on which they grow. We find that the elastic stress stored in deformed agar is orders of magnitude larger than the drag stress associated with pulling fluid through the agar matrix. The stress exerted by the biofilm is nearly the same as the osmotic pressure generated by the EPS, and mutant colonies incapable of producing EPS exert much lower levels of stress. The fluid flow rate into B. subtilis biofilms suggest that EPS generated pressure provides some metabolic benefit as colonies expand in volume. These results reveal that long-term biofouling and colony expansion may be tied to the hydraulic permeability and elasticity of the surfaces that biofilms colonize.

SYNOPSISThe purpose of this research is to prepare high solute permeability membranes for hemodialysis by plasma depositing hydrophilic monomers onto chemically treated or O2 plasma etched Nylon 4 substrate. The factors that affect the performances of membranes, such as deposition conditions and chemical or plasma etching conditions, were studied. The monomers used in this study were 1-vinyl-2-pyrrolidone ( V P ) , 2-Hydroxyethyl methacrylate (HEMA), and Methyl methacrylate (MMA) . The permeabilities of NaCl, urea, vitamin BIZ, and albumin were measured, as were the water content, hydration, diffusivity, partition coefficient, and protein adsorption ratio of fibrinogen to albumin by membrane surface of plasma deposited membranes. plasma modified to improve the surface energy, water content, and transport fluxes for dialysis by Lai et a1.5*6 Lai et al. used plasmas to induce hydrophilic monomers to graft onto Nylon 4 membranes for reverse osmosis desalination. Plasma deposition has been utilized to increase surface energy, plasma polymerization, etching in membrane modification, 7-9 and biomedical applications."-" Plasma polymerized surfaces are in both smooth and textured configurations, and tend to be relatively nonthrombogenic.12The purpose of this study is to improve the permeability hemodialysis and the mole ratio of adsorbed fibrinogen t o adsorbed albumin of membranes by plasma depositing the hydrophilic monomers, such as 1-Vinyl-2-pyrrolidone (VP) , 2-Hydroxyethyl methacrylate ( HEMA), and Methyl methacrylate ( MMA) , onto chemical or O2 plasma treated Nylon 4 substrate. The dialysis permeability, hydration, water content, diffusion coefficient, partition coefficient, and protein absorption ratio of fibrinogen to albumin by membrane surface of plasma deposited membranes are measured. The solutes 1431