Impacts of Urbanization on Base Flow and Recharge Rates, Northeastern Illinois: Summary of Year 1 Activities

During year one of a two-year project to investigate the impacts of urbanization on base flow and ground-water recharge rates in northeastern Illinois, three gaged watersheds in urbanized areas of northeastern Illinois, and one watershed located in rural northwestern Illinois, have been selected for study. The gages have a common period of record extending from October 1952 through the present, a period during which the northeastern Illinois watersheds underwent substantial urbanization. Mean daily discharge data from the gages have been analyzed using an automated hydrograph separation technique, and monthly estimates of mean total discharge, base flow, and direct runoff have been calculated. Spearman rank correlation coefficients indicate a stronger correlation between precipitation and total discharge, base flow, and direct runoff in the northeastern Illinois watersheds than in the rural watershed. Smoothed time-series plots of total discharge, base flow, and direct runoff in the urban watersheds are less consistent with precipitation than similar plots constructed from the rural watershed data. The trends indicate that rates of direct runoff have overtaken rates of base flow in two of the three northeastern Illinois watersheds, but in one of these watersheds, this relationship probably reflects the cessation of effluent discharges to the stream. In general, double-mass curve analysis suggests that, relative to the rural watershed, base flow in the urban watersheds has proportionally decreased, and direct runoff has proportionally increased. The trends suggested by the smoothed time-series plots and the double-mass curves are consistent with a conceptual model of the northeastern Illinois watersheds in which sewering and impervious surfaces have reduced infiltration, and thence ground-water recharge and base flow, in the watersheds.Ope

Overview of MultiLayer Metal Insulation Development for Small Stirling Convertors at NASA Glenn Research Center

A small Stirling convertor is currently under development at the NASA Glenn Research Center to produce one watt of electrical power from eight watts of heat. Previous radioisotope power systems made use of the General-Purpose Heat Source (GPHS) which produces 250 watts of heat but is unsuitable for a one-watt Stirling convertor. The only other qualified heat source available is the Light-Weight Radioisotope Heating Unit (LWRHU), which produces one watt of heat and is primarily used to provide heat to electronics and instrumentation to maintain their appropriate operating temperature. Unfortunately, the LWRHU has a heat flux of 272 W/meters squared compared to the GPHS heat flux of 6000 W/m2 which greatly increases the demands on the insulation to ensure that enough of the heat produced is available to the convertor and not lost to the environment. An analysis was performed that showed that the insulation must have an effective thermal conductivity of 0.005 W/mK or better for the system to function. A multi-layer metal insulation package was designed and a prototype was fabricated and tested to investigate the feasibility of this design. While the prototype did not meet the requirements perfectly, the lessons learned are being used to generate an improved thermal model using the test data so that a second iteration can developed that will meet the performance requirements with a much higher confidence

Fabrication and Testing of a Nonstandard Thin-Film Heat Flux Sensor for Power System Applications

Stirling convertors are being operated by NASA Glenn Research Center for many years to demonstrate a Radioisotope Power System (RPS) capable of providing reliable power for potential multi-year space missions. Techniques used to monitor Stirling convertors for change in performance include measurements of temperature, pressure, energy addition, and power output. It is difficult to measure energy addition to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat energy addition to a Stirling convertor. The one micron thick, Gold vs. Platinum thermocouples were designed to make a noninvasive temperature measurement on the surface of an Alumina ceramic disk located between the heat source and Stirling convertor. Fabrication techniques included creation of ceramic substrates, which hold the thermocouples, using the slipcasting technique and creation of the thin metallic film thermocouples using Physical Vapor Deposition (PVD). The effort succeeded in designing and fabricating unique sensors which, for the first time, were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700°C in air for 10,000 hours. The heat transfer measurements are discussed. Also, the sensors were examined after being removed when the test was complete

Fabrication and Testing of a Nonstandard Thin-Film Heat Flux Sensor for Power System Applications

Stirling convertors are being operated by NASA Glenn Research Center for many years to demonstrate a Radioisotope Power System (RPS) capable of providing reliable power for potential multi-year space missions. Techniques used to monitor Stirling convertors for change in performance include measurements of temperature, pressure, energy addition, and power output. It is difficult to measure energy addition to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat energy addition to a Stirling convertor. The one micron thick, Gold vs. Platinum thermocouples were designed to make a noninvasive temperature measurement on the surface of an Alumina ceramic disk located between the heat source and Stirling convertor. Fabrication techniques included creation of ceramic substrates, which hold the thermocouples, using the slipcasting technique and creation of the thin metallic film thermocouples using Physical Vapor Deposition (PVD). The effort succeeded in designing and fabricating unique sensors which, for the first time, were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700°C in air for 10,000 hours. The heat transfer measurements are discussed. Also, the sensors were examined after being removed when the test was complete

Calculating the transfer function of noise removal by principal component analysis and application to AzTEC observations

Instruments using arrays of many bolometers have become increasingly common in the past decade. The maps produced by such instruments typically include the filtering effects of the instrument as well as those from subsequent steps performed in the reduction of the data. Therefore interpretation of the maps is dependent upon accurately calculating the transfer function of the chosen reduction technique on the signal of interest. Many of these instruments use non-linear and iterative techniques to reduce their data because such methods can offer improved signal-to-noise over those that are purely linear, particularly for signals at scales comparable to that subtended by the array. We discuss a general approach for measuring the transfer function of principal component analysis (PCA) on point sources that are small compared to the spatial extent seen by any single bolometer within the array. The results are applied to previously released AzTEC catalogues of the COSMOS, Lockman Hole, Subaru XMM-Newton Deep Field, GOODS-North and GOODS-South fields. Source flux density and noise estimates increase by roughly +10 per cent for fields observed while AzTEC was installed at the Atacama Submillimeter Telescope Experiment and +15-25 per cent while AzTEC was installed at the James Clerk Maxwell Telescope. Detection significance is, on average, unaffected by the revised technique. The revised photometry technique will be used in subsequent AzTEC releases.Comment: 14 pages, 4 figure

King Gough : Madness Or Magnificence? A Retrospective View Of The 1975 APSA Conference

In 2000, I chose to mark the 25th anniversary by a personal project to complement the formal conference on the topic of the Whitlam years held later in the year on the specific anniversary. As President of APSA in that momentous year, I chaired the committee which organised the conference that year, held amid damp conditions at the Canberra CAE. The conference occurred in the hothouse environment of July 1975, a period of unprecedented levels of political uncertainty. Indeed, the very title of the conference, "The First Thousand Days of Labor" devised by John Power inadvertently begged a momentous question: Would Whitlam last beyond his first thousand days? Answer - just, 1074. The attendance at the conference, over 400 including the down-town public servants, was also abnormally large. Finally, the format of the conference, squeezing all contributors into a straight-jacket of a single theme, was also an innovation - and never repeated because some vocal groups felt disenfranchised by its intellectual parochialism. These special characteristics of the conference justify this exercise in retrospectivity. It fits into a theme of reviewing Australian federalism since 1975 was such a cataclysmic year. It was a mirror of where the Whitlam government was taking the public policy agenda - towards institutional reforms in the public service, reaching into local and regional communities, creating new slants on federalism and engaging in an activist and independent foreign policy (not least with respect to East Timor). It was also engaging the scholarly attention of a wide variety of participants not normally much in evidence at APSA conferences, including senior administrators, serving politicians journalists, union officials and ministerial staff. Some of these have faded into relative obscurity or joined their ancestors, but the list of - then/now - occupations in the Appendices suggest an unusual diversity of backgrounds at the time and subsequent to the conference. I decided to send the conference contributors a copy of their original papers and respond to the questions of how much things have changed since they wrote and how accurate were any predictions and analyses they offered. What did the differences tell us about thet state of the discipline of political science then and now? The papers are arranged as they were in 1975 - in four sections : "Government, Parliament and Parliamentarians", "Machinery of Government", "Federalism" and "Public Policy". A fifth section, on international relations could not be sustained in this retrospective as few authors could be contacted who had any interest in reviewing what they had written that long ago and many had not survived. Hard copies of this retrospective were tabled at the 2000 APSA conference. The original 1975 papers were photocopied and bound into two volumes with the modest technology then available and can still be found in many university libraries which received free copies from APSA. They will be catalogued as "The First Thousand Days of Labor" perhaps with attributions to compilers Scott, Richardson, Power and Wettenhall

NASA Proof-of-Concept 1-W(sub e) Stirling Convertor Development for Small Radioisotope Power Systems

Low power Stirling convertors are being developed at NASA Glenn Research Center to provide future small spacecraft with electrical power by converting heat from one or more Light Weight Radioisotope Heater Units (LWRHU). An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. A variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize low power Radioisotope Power Systems (RPS) for probes, landers, rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data such as, radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies propose using fractional versions of the General Purpose Heat Source or multiple LWRHUs to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Efforts to develop the concept have focused on maturation of a 1-We convertor and controller design and performance evaluation of an evacuated metal foil insulation. A proof-of-concept 1-We convertor, controller, and evacuated metal foil insulation package have been fabricated and are undergoing characterization testing. The current status, findings, and path forward for the effort are explained in this paper

Advanced Stirling Convertor Testing at NASA Glenn Research Center

The NASA Glenn Research Center (GRC) has been testing high-efficiency free-piston Stirling convertors for potential use in radioisotope power systems (RPSs) since 1999. The current effort is in support of the Advanced Stirling Radioisotope Generator (ASRG), which is being developed by the U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower, Inc., and the NASA GRC. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs) to convert thermal energy from a radioisotope heat source into electricity. As reliability is paramount to a RPS capable of providing spacecraft power for potential multi-year missions, GRC provides direct technology support to the ASRG flight project in the areas of reliability, convertor and generator testing, high-temperature materials, structures, modeling and analysis, organics, structural dynamics, electromagnetic interference (EMI), and permanent magnets to reduce risk and enhance reliability of the convertor as this technology transitions toward flight status. Convertor and generator testing is carried out in short- and long-duration tests designed to characterize convertor performance when subjected to environments intended to simulate launch and space conditions. Long duration testing is intended to baseline performance and observe any performance degradation over the life of the test. Testing involves developing support hardware that enables 24/7 unattended operation and data collection. GRC currently has 14 Stirling convertors under unattended extended operation testing, including two operating in the ASRG Engineering Unit (ASRG-EU). Test data and high-temperature support hardware are discussed for ongoing and future ASC tests with emphasis on the ASC-E and ASC-E2

Heart enhancers with deeply conserved regulatory activity are established early in zebrafish development.

During the phylotypic period, embryos from different genera show similar gene expression patterns, implying common regulatory mechanisms. Here we set out to identify enhancers involved in the initial events of cardiogenesis, which occurs during the phylotypic period. We isolate early cardiac progenitor cells from zebrafish embryos and characterize 3838 open chromatin regions specific to this cell population. Of these regions, 162 overlap with conserved non-coding elements (CNEs) that also map to open chromatin regions in human. Most of the zebrafish conserved open chromatin elements tested drive gene expression in the developing heart. Despite modest sequence identity, human orthologous open chromatin regions recapitulate the spatial temporal expression patterns of the zebrafish sequence, potentially providing a basis for phylotypic gene expression patterns. Genome-wide, we discover 5598 zebrafish-human conserved open chromatin regions, suggesting that a diverse repertoire of ancient enhancers is established prior to organogenesis and the phylotypic period