9,645 research outputs found
Freeze Prediction Model
Measurements of wind speed, net irradiation, and of air, soil, and dew point temperatures in an orchard at the Rock Springs Agricultural Research Center, as well as topographical and climatological data and a description of the major apple growing regions of Pennsylvania were supplied to the University of Florida for use in running the P-model, freeze prediction program. Results show that the P-model appears to have considerable applicability to conditions in Pennsylvania. Even though modifications may have to be made for use in the fruit growing regions, there are advantages for fruit growers with the model in its present form
Building an On-Ramp to Children's Health Coverage: A Report on California's Express Lane Eligibility Program
Documents the successes and current policy and procedural barriers to enrolling eligible but uninsured children through California's Express Lane Eligibility initiative, which has been piloted in 72 schools in five school districts across California
A microprocessor based anti-aliasing filter for a PCM system
Described is the design and evaluation of a microprocessor based digital filter. The filter was made to investigate the feasibility of a digital replacement for the analog pre-sampling filters used in telemetry systems at the NASA Ames-Dryden Flight Research Facility (DFRF). The digital filter will utilize an Intel 2920 Analog Signal Processor (ASP) chip. Testing includes measurements of: (1) the filter frequency response and, (2) the filter signal resolution. The evaluation of the digital filter was made on the basis of circuit size, projected environmental stability and filter resolution. The 2920 based digital filter was found to meet or exceed the pre-sampling filter specifications for limited signal resolution applications
Numerical investigation of controlling interfacial instabilities in non-standard Hele-Shaw configurations
Viscous fingering experiments in Hele-Shaw cells lead to striking pattern
formations which have been the subject of intense focus among the physics and
applied mathematics community for many years. In recent times, much attention
has been devoted to devising strategies for controlling such patterns and
reducing the growth of the interfacial fingers. We continue this research by
reporting on numerical simulations, based on the level set method, of a
generalised Hele-Shaw model for which the geometry of the Hele-Shaw cell is
altered. First, we investigate how imposing constant and time-dependent
injection rates in a Hele-Shaw cell that is either standard, tapered or
rotating can be used to reduce the development of viscous fingering when an
inviscid fluid is injected into a viscous fluid over a finite time period. We
perform a series of numerical experiments comparing the effectiveness of each
strategy to determine how these non-standard Hele-Shaw configurations influence
the morphological features of the inviscid-viscous fluid interface. Tapering
plates in either converging or diverging directions leads to reduced metrics of
viscous fingering at the final time when compared to the standard parallel
configuration, especially with carefully chosen injection rates; for the
rotating plate case, the effect is even more dramatic, with sufficiently large
rotation rates completely stabilising the interface. Next, we illustrate how
the number of non-splitting fingers can be controlled by injecting the inviscid
fluid at a time-dependent rate while increasing the gap between the plates.
Simulations compare well with previous experimental results for various
injection rates and geometric configurations. Further, we demonstrate how the
fully nonlinear dynamics of the problem affect the number of fingers that
emerge and how well this number agrees with predictions from linear stability
analysis
A catalog of radio observations of Jupiter 1961-1964
Catalog of radio observations of Jupiter 1961 to 196
Some Effects of Simulated Acid Rain on Cool Season Turfgrasses
Six varieties of cool season turfgrasses were exposed to simulated acid rainfall with treatments consisting of a sulfuric acid solution, a nitric acid solution, and a 50-50 mixture of both. Each solution was used to make acid rain of pHs 3.0, 2.5, 2.0, and 1.5.
Height measurements showed decreases in growth throughout the experiment for all treatments except the nitric and 50-50 acid treatments at pHs of 2.0 and 1.5, which maintain fairly constant growth. Analysis of nitrate, phosphorous, and potassium levels in the soil indicated heavy leaching of the nitrates and potassium from most soil samples, which probably account for the reduced growth observed. There appeared to be an increase in leaching of potassium from samples recieving the more acidic treatments. Grasses with little decrease in growth showed greater foliar injury than did the stunted plants. Greater foliar injury was also observed at the beginning of the experiment when all the plants were fairly uniform in height. Soil pH showed little change except for the pH 1.5 sulfuric acid treatments, which caused some increase in acidity. There was no correlation between the soil pH and turfgrass height or foliar injury.
A separate, related experiment was conducted to investigate a new chlorophyll extraction procedure reported in the literature for obtaining chlorophyll concentrations expressed as mg chlorophyll per gram dry weight.
Chlorophyll extracts from the injured plants showed a reduction in chlorophyll A, chlorophyll B, and total chlorophyll. Injured plants also showed a decrease in chlorophyll A to B ratios. In addition, higher percentages of chlorophyll were extracted from uninjured tissue than from injured tissue.
Length of storage studies indicated that chlorophyll extracts were stable for at least ten days when stored in the dark
Biotechnological utilisation of Nephrops shell waste
Shellfish processing results in the disposal of large quantities of waste to landfill sites. This project sought to deal with the issue of the processing of marine crustacean waste, specifically that of the prawn, Nephrops norvegicus.
The exoskeleton of Nephrops norvegicus contains chitin, β-(1→4)-N-acetyl-D-glucosamine.
In this study shell waste was demineralised, via lactic acid fermentation, using a commercial silage inoculant. The product contained 11.2% (w/w) ash, 31.1% (w/w) protein and 53.5% (w/w) chitin. Addition of the proteolytic enzyme, bromelain and a nitrogen source to the fermentation system led to deproteinisation and further demineralisation of the shell. The final product contained 4.2% (w/w) ash, 5.3% (w/w) protein and 79.6% (w/w) chitin.
Chitin is relatively inert but can be converted to its more reactive derivative, chitosan, by deacetylation. Chitosan, prepared from bioprocessed shell waste, was investigated as a potential coating for urinary catheters. Attempts are currently being made to prevent blockage of these biomedical devices due to mineral ions, via the use of different manufacturing materials. Shell waste that had been demineralised using lactic acid fermentation was deacetylated using 50% (w/v) NaOH at 90oC. Membranes were prepared from the resultant chitosan. After immersion in a bath containing artificial urine, adherence of calcium and magnesium ions to the membranes was measured and compared with adherence of the same ions to polyurethane membranes. Adherence of calcium to the chitosan membranes was not higher than adherence to the polyurethane control membranes. Adherence of magnesium ions was significantly less than to the polyurethane control. The chitosan was hence shown to have potential for use as a coating for urinary catheters
Variability of Southern Ocean Jets near Topography
ISI Document Delivery No.: AA3VY Times Cited: 0 Cited Reference Count: 33 Cited References: Amante C, 2009, NGDC24 NOAA NESDIS, V24, P1 Arbic BK, 2012, J GEOPHYS RES-OCEANS, V117, DOI 10.1029/2011JC007367 Berloff P, 2011, J FLUID MECH, V686, P534, DOI 10.1017/jfm.2011.345 Berloff P, 2007, J PHYS OCEANOGR, V37, P2363, DOI 10.1175/JPO3118.1 Chapman CC, 2013, J PHYS OCEANOGR, V43, P990, DOI 10.1175/JPO-D-12-0123.1 Dewar WK, 1998, J MAR RES, V56, P295, DOI 10.1357/002224098321822320 Dibarboure G, 2011, MAR GEOD, V34, P214, DOI 10.1080/01490419.2011.584826 Graham RM, 2012, J GEOPHYS RES-OCEANS, V117, DOI 10.1029/2012JC007887 Hogg AM, 2003, MON WEATHER REV, V131, P2261, DOI 10.1175/1520-0493(2003)1312.0.CO;2 Hughes CW, 2001, J GEOPHYS RES-OCEANS, V106, P2713, DOI 10.1029/1999JC900332 Hughes CW, 1996, J PHYS OCEANOGR, V26, P1375, DOI 10.1175/1520-0485(1996)0262.0.CO;2 Marshall DP, 2011, J MAR RES, V69, P309 ORSI AH, 1995, DEEP-SEA RES PT I, V42, P641, DOI 10.1016/0967-0637(95)00021-W Phillips H., 2000, THESIS U TASMANIA Rhines PB, 1994, CHAOS, V4, P313, DOI 10.1063/1.166011 Rintoul S. R., 2001, OCEAN CIRCULATION CL, P271, DOI DOI 10.1016/S0074-6142(01)80124-8 Rio MH, 2011, J GEOPHYS RES-OCEANS, V116, DOI 10.1029/2010JC006505 Smith S. W., 2003, SCI ENG GUIDE DIGITA Sokolov S, 2007, J PHYS OCEANOGR, V37, P1394, DOI 10.1175/JPO3111.1 Sokolov S, 2009, J GEOPHYS RES-OCEANS, V114, DOI 10.1029/2008JC005248 STERN ME, 1987, J GEOPHYS RES-OCEANS, V92, P10733, DOI 10.1029/JC092iC10p10733 Thompson AF, 2012, J PHYS OCEANOGR, V42, P956, DOI 10.1175/JPO-D-11-0135.1 Thompson AF, 2007, J ATMOS SCI, V64, P3214, DOI 10.1175/JAS4000.1 Thompson AF, 2008, PHILOS T R SOC A, V366, P4529, DOI 10.1098/rsta.2008.0196 Thompson AF, 2011, J GEOPHYS RES-OCEANS, V116, DOI 10.1029/2010JC006749 Thompson AF, 2010, J PHYS OCEANOGR, V40, P257, DOI 10.1175/2009JPO4218.1 Venaille A, 2011, GEOPHYS RES LETT, V38, DOI 10.1029/2011GL048401 Volker C, 1999, J PHYS OCEANOGR, V29, P1666, DOI 10.1175/1520-0485(1999)0292.0.CO;2 Volkov DL, 2008, J GEOPHYS RES-OCEANS, V113, DOI 10.1029/2008JC004841 Ward ML, 2011, OCEAN MODEL, V40, P133, DOI 10.1016/j.ocemod.2011.08.004 Wilks D.S., 2006, INT GEOPHYS SERIES, V91, P627 Williams PD, 2010, J FLUID MECH, V649, P187, DOI 10.1017/S0022112009993405 Williams RG, 2007, J PHYS OCEANOGR, V37, P2267, DOI 10.1175/JPO3120.1 Chapman, Christopher C. Morrow, Rosemary CNES; National Facility of the Australian Partnership for Advanced Computing; CSIRO Wealth from Oceans Flagship Scholarship The authors would like to acknowledge Drs. A. McC. Hogg and S. R. Rintoul for helpful discussions along with two anonymous reviewers whose comments greatly improved the manuscript. The altimeter products were produced by SSALTO/DUACS and distributed by AVISO with support from CNES. Numerical computations were supported by an award under the Merit Allocation Scheme on the National Facility of the Australian Partnership for Advanced Computing. C. C. Chapman is supported by a CSIRO Wealth from Oceans Flagship Scholarship. 0 AMER METEOROLOGICAL SOC BOSTON J PHYS OCEANOGRThe interaction of jets with topography in the Southern Ocean is investigated using 19 years of altimetry data. In particular, the "jet jumping" mode of variability, by which two or more jets passing close to the same topographic feature show strongly anticorrelated strengthening and weakening, is studied. Three regional case studies are described-the Southeast Indian Ridge south of Tasmania, the Macquarie Ridge south of New Zealand, and the Pacific-Antarctic Rise-where the jet jumping variability is found to occur. Using principal component analysis, the spatial patterns of variability show a vortex dipole forming on either side of a particular jet. For each regional study, it is found that the variability in strength of these vortices (as measured by the spatially averaged vorticity) is strongly correlated with time series of the principle component that describes the jet jumping variability. The observational analysis is complemented by a suite of idealized numerical experiments using a three-layer quasigeostrophic model with simple topography. The numerical results show similar spatial patterns of variability to those observed in the altimetric data. Internal variability is sufficient to generate jet jumping variability, as there is no time-varying external forcing applied in the model configuration. The simulations are used to investigate the effect of topographic scale and changing bottom friction. The authors find that both have a strong influence on the time scale of the variability, with larger topographic scales and higher bottom friction leading to faster time scales. This study shows that even in regions where the flow is strongly influenced by topography, Southern Ocean jet flow may exhibit low-frequency variability
Work Related Communication, Environmental Uncertainty, and Subunit Effectiveness: A Second Look at the Information Processing Approach to Subunit Communication
The article discusses communication in organizations and looks at the effectiveness of contingency theory in analyzing operational research. The author critiques earlier research in this area, specifically by Boehm, Zedeck, and Tushman. She uses data from 90 of 100 subunits of a midwest state Extension Service. Questionnaires were sent out to assess work-related communications and information exchanges between the subunits, environmental conditions within each subunit, and the effectiveness of each office
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