Management gaps analysis: a case study of groundwater resource management in New Zealand

The primary objective of this project is to identify gaps, whether real or perceived, that hinder effective groundwater management in New Zealand. These gaps show as gaps in information, gaps in implementation, gaps in technological and management tools, and gaps in understanding of fundamental processes. The secondary objective is to propose a management strategy to close the identified gaps. Several methods are used to meet these objectives: surveys distributed to selected staff in each regional council; the review of various written reports; the analysis of land-use databases; and private consultation within each regional council. Results show that groundwater management in New Zealand is generally reactionary with the main gaps being in strategic planning and national guidelines. Most gaps appear to be predominantly information and implementation issues. In some cases there are gaps in the understanding of fundamental processes within an aquifer system, including the long-term effects of land-use on groundwater quality. An adaptive management approach is suggested as a means of closing these gaps.     

Cryogenic micro-calorimeters for low energy beta spectroscopy

We are using calorimeters with completely encapsulated sources to study low energy beta spectra. Our devices work as true calorimeters in the sense that they totally absorb and sum all the various quanta released in a decay into a single temperature pulse with amplitude proportional to the total energy deposited. We use a neutron transmutation doped (NTD) germanium thermistor as the temperature sensor and superconducting NbTi leads, which form a weak thermal link to the cold stage (80 mK). We have been using superconducting tin as our absorber material, and we discuss various techniques for source and absorber preparation. Annealing the absorber leads to shorter pulses with larger amplitude, and significantly improves detector performance. The production of a device to study the beta decay of¹⁰⁷Pd presented special difficulties due to the low specific activity of this isotope (halflife 6.5×10⁶ y), and the low enrichment (15%) that was available. This meant it was necessary to incorporate a large amount of palladium into our tin absorber. We found we could avoid a corresponding increase in heat capacity by forming a superconducting PdSn alloy.     

The performance of pigtailed annealed proton exchange LiNbO/sub 3/ modulators at cryogenic temperatures

Integrated optic modulators have been proposed for transmitting signals from electronic and electrooptic devices which must operate at 77 K and colder. In this letter, the V/spl pi/ of LiNbO/sub 3/ modulators at temperatures as cold as 10 K are measured. A /spl sim/9.25% increase over room temperature values is seen. This increase is attributed primarily to a temperature dependence in r/sub 33/. In addition, temperature-induced insertion loss changes are evaluated for two different pigtailing techniques and one is shown to be suitable for cryogenic operation.     

Delivery of iPS‐NPCs to the Stroke Cavity within a Hyaluronic Acid Matrix Promotes the Differentiation of Transplanted Cells

Stroke is the leading cause of adult disability with ≈80% being ischemic. Stem cell transplantation has been shown to improve functional recovery. However, the overall survival and differentiation of these cells is still low. The infarct cavity is an ideal location for transplantation as it is directly adjacent to the highly plastic peri‐infarct region. Direct transplantation of cells near the infarct cavity has resulted in low cell viability. Here, neural progenitor cells derived from induce pluripotent stem cells (iPS‐NPC) are delivered to the infarct cavity of stroked mice encapsulated in a hyaluronic acid hydrogel matrix to protect the cells. To improve the overall viability of transplanted cells, each step of the transplantation process is optimized. Hydrogel mechanics and cell injection parameters are investigated to determine their effects on the inflammatory response of the brain and cell viability, respectively. Using parameters that balanced the desire to keep surgery invasiveness minimal and cell viability high, iPS‐NPCs are transplanted to the stroke cavity of mice encapsulated in buffer or the hydrogel. While the hydrogel does not promote stem cell survival one week post‐transplantation, it does promote differentiation of the neural progenitor cells to neuroblasts.     

C.A.T. scans

With the rapidly mounting cost of medical care in hospitals, physicians must seek alternative forms of therapy for illnesses that could conceivably be treated by less confining methods. One appraoch to this problem is the Psoriasis Day Care Center, where psoriasis patients with extensive disease are treated during the day and allowed to return home at night. The advantages include reduced cost, accessibility for more patients, and superior therapeutic results. This day care center concept could be equally applicable to other diseases now routinely treated by complete hospitalization.     

Effect of TCE concentration and dissolved groundwater solutes on NZVI-promoted TCE dechlorination and H2 evolution

Nanoscale zero-valent iron (NZVI) is used to remediate contaminated groundwater plumes and contaminant source zones. The target contaminant concentration and groundwater solutes (NO3-, Cl-, HCO3-, SO4(2-), and HPO4(2-)) should affect the NZVI longevity and reactivity with target contaminants, but these effects are not well understood. This study evaluates the effect of trichloroethylene (TCE) concentration and common dissolved groundwater solutes on the rates of NZVI-promoted TCE dechlorination and H2 evolution in batch reactors. Both model systems and real groundwater are evaluated. The TCE reaction rate constant was unaffected by TCE concentration for [TCE] < or = 0.46 mM and decreased by less than a factor of 2 for further increases in TCE concentration up to water saturation (8.4 mM). For [TCE] > or = 0.46 mM, acetylene formation increased, and the total amount of H2 evolved at the end of the particle reactive lifetime decreased with increasing [TCE], indicating a higher Fe0 utilization efficiency for TCE dechlorination. Common groundwater anions (5mN) had a minor effect on H2 evolution but inhibited TCE reduction up to 7-fold in increasing order of Cl- < SO4(2-) < HCO3- < HPO4(2). This order is consistent with their affinity to form complexes with iron oxide. Nitrate, a NZVI-reducible groundwater solute, present at 0.2 and 1 mN did not affect the rate of TCE reduction but increased acetylene production and decreased H2 evolution. NO3- present at > 3 mM slowed TCE dechlorination due to surface passivation. NO3- present at 5 mM stopped TCE dechlorination and H2 evolution after 3 days. Dissolved solutes accounted for the observed decrease of NZVI reactivity for TCE dechlorination in natural groundwater when the total organic content was small (< 1 mg/L).     

Cholesterol interference in analysis of fatty acid methyl esters

In the course of isolating and analyzing the fatty acid methyl esters (FAME) from steelhead trout (Salmo gairdneri) eggs and sac fry, a component was found on gas liquid chromatography to have a retention time longer than any characteristic polyunsaturated fatty acid previously encountered in trout. Subsequent purification and analysis demonstrated this component to be cholesterol. Thus, cholesterol and related compounds can interfere in the analysis of FAME when the methyl esters are prepared by transesterification.     

Quantitative proton MRS assessment of citrate heterogeneity in normal prostate

Water-suppressed proton spectra of the two major anatomical regions of the normal prostate were acquired with a commercial phased-array multicoil. The spectra demonstrated excellent signal-to-noise ratio and spectral resolution allowing identification of peaks from choline, creatine, and amino acids, as well as a major peak from citrate. Quantification of the citrate peak using tissue water as an internal concentration reference revealed a marked variability among different volunteers. In each case, citrate was consistently twofold to threefold greater in the peripheral zone than in the central gland. The results demonstrate heterogeneity of citrate within the prostate and suggest significant differences in the cytology and hormonal control of citrate synthesis among individuals.     

A predictive technique for evaluating structural vibration gain of damped suspensions in hard disk drives

The problem of resonant vibration of suspensions used in hard disk drives has been the subject of ongoing research. This study focuses on implementation of a finite element modeling methodology to predict the response for a suspension that includes an added damping component, either as a traditional constraint layer damper or as a design tool. High gains in suspensions result in off-track of the slider, which is the mechanism for reading and writing data. Analytical methodology uses the concept of modal strain energy to predict the modal damping of the structure at each resonant mode. Loss factors and strain energies of each material used in the structure quantify the amount of modal damping at a particular mode. Development of the methodology allows optimization studies of standard damping applications, such as a constraint layer damper. In addition, the methodology enables FEA as a design tool to develop innovative solutions for improved efficiency and higher performance.