310 research outputs found

    Development of Mobile Solar Evaluation Laboratory & Technical and Economic Performance of the Goldade Site-Built Air Collector

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    The Great Basin climate type is ideal for the utilization of solar winter space heat from air collectors; perhaps the most economically viable option for solar space heating is that of site built air collectors (SBAC). Unfortunately SBACs are a rarely utilized technology primarily because there is presently no standard method to test these types of collectors. This thesis provides a viable testing method for SBACs and the theoretical calculations required to develop testing and provide ratings based on industry standards. This leads to development of the Mobile Solar Evaluation Laboratory (MSEL).The Goldade Family built a 128 ft2 solar air heater for winter space heating, and the MSEL was employed to evaluate the technical and economic performance of that system. Theory and field testing correlated well, and it was proven that the MSEL accurately predicts SBAC performance. In most Northern Nevada households solar space heating can be cost effective. Solar space heating also reduces substantial CO2 from being added to the atmosphere

    Search for Tidal Dwarf Galaxies Candidates in a Sample of Ultraluminous Infrared Galaxies

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    (ABRIDGED) Star-forming small galaxies made out of collisional debris have been found in a variety of merging systems. So far only a few of them are known in ULIRGs although they show clear signs of interactions. Whether external star formation may take place in such objects is an open question. The aim of this paper is to identify and characterise the physical and kinematic properties of the external star forming regions in a sample of ULIRGs, including TDG candidates, using optical IFS and high angular resolution HST imaging. We have found that the presence of external star-forming regions is common with 12 objects being identified in 5 ULIRGs. These regions show a large range of dynamical mass up to 1x10^{10} M_sun, with average sizes of ~750 pc. In addition, the line ratios, metallicities and H\alpha equivalent widths are typical of young bursts of star formation (age ~ 5-8 Myr), and similar to those of other TDG candidates. Their extinction corrected H\alpha luminosities lead to masses for the young stellar component of ~2x10^6 - 7x10^8 M_sun. The likelihood of survival of these regions as TDGs is discussed based on their structural and kinematic properties. Most of these systems follow the relation between effective radius and velocity dispersion found for globular clusters and Ellipticals, which suggests they are stable against internal motions. The stability against forces from the parent galaxy have been studied and a comparison of the data with the predictions of dynamical evolutionary models is also performed. Five regions out of twelve show High-Medium or High likelihood of survival. Our best candidate, which satisfy all the utilized criteria, is located in the advanced merger IRAS15250+3609 and presents a velocity field decoupled from the relatively distant parent galaxy.Comment: 14 pages, 7 figures; A&A accepte

    Efficient Liquid Animation: New Discretizations for Spatially Adaptive Liquid Viscosity and Reduced-Model Two-Phase Bubbles and Inviscid Liquids

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    The work presented in this thesis focuses on improving the computational efficiency when simulating viscous liquids and air bubbles immersed in liquids by designing new discretizations to focus computational effort in regions that meaningfully contribute to creating realistic motion. For example, when simulating air bubbles rising through a liquid, the entire bubble volume is traditionally simulated despite the bubble’s interior being visually unimportant. We propose our constraint bubbles model to avoid simulating the interior of the bubble volume by reformulating the usual incompressibility constraint throughout a bubble volume as a constraint over only the bubble’s surface. Our constraint method achieves qualitatively similar results compared to a two-phase simulation ground-truth for bubbles with low densities (e.g., air bubbles in water). For bubbles with higher densities, we propose our novel affine regions to model the bubble’s entire velocity field with a single affine vector field. We demonstrate that affine regions can correctly achieve hydrostatic equilibrium for bubble densities that match the surrounding liquid and correctly sink for higher densities. Finally, we introduce a tiled approach to subdivide large-scale affine regions into smaller subregions. Using this strategy, we are able to accelerate single-phase free surface flow simulations, offering a novel approach to adaptively enforce incompressibility in free surface liquids without complex data structures. While pressure forces are often the bottleneck for inviscid fluid simulations, viscosity can impose orders of magnitude greater computational costs. We observed that viscous liquids require high simulation resolution at the surface to capture detailed viscous buckling and rotational motion but, because viscosity dampens relative motion, do not require the same resolution in the liquid’s interior. We therefore propose a novel adaptive method to solve free surface viscosity equations by discretizing the variational finite difference approach of Batty and Bridson (2008) on an octree grid. Our key insight is that the variational method guarantees a symmetric positive definite linear system by construction, allowing the use of fast numerical solvers like the Conjugate Gradients method. By coarsening simulation grid cells inside the liquid volume, we rapidly reduce the degrees-of-freedom in the viscosity linear system up to a factor of 7.7x and achieve performance improvements for the linear solve between 3.8x and 9.4x compared to a regular grid equivalent. The results of our adaptive method closely match an equivalent regular grid for common scenarios such as: rotation and bending, buckling and folding, and solid-liquid interactions

    Playa-Lunette System Mapping and Characterization in the High Plains of Western Kansas

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    Playa-lunette systems (PLSs) are common landscape features in the Great Plains that have been investigated from various perspectives including ecologic, geographic, hydrologic, and geologic. One of the region’s most important water sources is the High Plains Aquifer (HPA), an expansive groundwater reservoir located beneath the PLSs, which has been susceptible to groundwater shortages, water table declines, and pollution throughout much of the High Plains due primarily to anthropogenic influences. This investigation takes on a new perspective, that of the geomorphology of playa basins and associated lunettes using LiDAR in a GIS environment. Playa-lunette systems were mapped using an objective method, or the largest closed contour (LCC) method, and a subjective method, also known as the subjectively chosen contour method (SC), with contours derived from a high-resolution LiDAR DEM. Basic 2-D attributes, e.g., area, perimeter, and orientation, were computed for the PLSs. The basin and lunette locations are consistent (perpendicular and parallel long axes, respectively) with late Pleistocene-early Holocene northwesterly paleo-winds of the last glacial period, with lunettes commonly being located south to south-easterly of the basins. This dataset fills the need for the mapping of the basins and compares two mapping methods with contours generated from high-resolution data. The assumption is that the SC method produces a visually ideal dataset, but the cons are that it is subjective and it requires more knowledge of PLSs. The LCC method is objective and has a set criteria to follow, producing more consistent results. A subset of 40 ideal playa-lunette systems (out of the 104 study sites from Bowen et al., 2018) were selected for a directional trends analysis and other 2-D metrics. Overall, the LCC method was comparable to the SC method, though the LCC method had a slight overestimation of the features comprising the PLSs. The LCC method and SC method mapped playas more consistently with the same contour than lunettes. A relatively high correlation was found with regression plots of long axial orientation values between pairs of the datasets, as well as t-test results showing that these results are statistically similar

    What are the living conditions and health status of those who don't report their migration status? a population-based study in Chile

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    BACKGROUND: Undocumented immigrants are likely to be missing from population databases, making it impossible to identify an accurate sampling frame in migration research. No population-based data has been collected in Chile regarding the living conditions and health status of undocumented immigrants. However, the CASEN survey (Caracterizacion Socio- Economica Nacional) asked about migration status in Chile for the first time in 2006 and provides an opportunity to set the base for future analysis of available migration data. We explored the living conditions and health of self-reported immigrants and respondents who preferred not to report their migration status in this survey. METHODS: Cross-sectional secondary analysis of CASEN survey in Chile in 2006. Outcomes: any disability, illness/accident, hospitalization/surgery, cancer/chronic condition (all binary variables); and the number of medical/emergency attentions received (count variables). Covariates: Demographics (age, sex, marital status, urban/rural, ethnicity), socioeconomic status (education level, employment status and household income), and material standard of living (overcrowding, sanitation, housing quality). Weighted regression models were estimated for each health outcome, crude and adjusted by sets of covariates, in STATA 10.0. RESULTS: About 1% of the total sample reported being immigrants and 0.7% preferred not to report their migration status (Migration Status - Missing Values; MS-MV). The MS-MV lived in more deprived conditions and reported a higher rate of health problems than immigrants. Some gender differences were observed by health status among immigrants and the MS-MV but they were not statistically significant. Regressions indicated that age, sex, SES and material factors consistently affected MS-MVs’ chance of presenting poor health and these patterns were different to those found among immigrants. Great heterogeneity in both the MS-MV and the immigrants, as indicated by wide confidence intervals, prevented the identification of other significantly associated covariates. CONCLUSION: This is the first study to look at the living conditions and health of those that preferred not to respond their migration status in Chile. Respondents that do not report their migration status are vulnerable to poor health and may represent undocumented immigrants. Surveys that fail to identify these people are likely to misrepresent the experiences of immigrants and further quantitative and qualitative research is urgently required

    Motivational interviewing to enhance nicotine patch treatment for smoking cessation among homeless smokers: a randomized controlled trial

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    Aims To assess the effects of adding motivational interviewing ( MI ) counseling to nicotine patch for smoking cessation among homeless smokers. Design Two‐group randomized controlled trial with 26‐week follow‐up. Participants and setting A total of 430 homeless smokers from emergency shelters and transitional housing units in M inneapolis/ S t Paul, M innesota, USA . Intervention and measurements All participants received 8‐week treatment of 21‐mg nicotine patch. In addition, participants in the intervention group received six individual sessions of MI counseling which aimed to increase adherence to nicotine patches and to motivate cessation. Participants in the standard care control group received one session of brief advice to quit smoking. Primary outcome was 7‐day abstinence from cigarette smoking at 26 weeks, as validated by exhaled carbon monoxide and salivary cotinine. Findings Using intention‐to‐treat analysis, verified 7‐day abstinence rate at week 26 for the intervention group was non‐significantly higher than for the control group (9.3% versus 5.6%, P  = 0.15). Among participants who did not quit smoking, reduction in number of cigarettes from baseline to week 26 was equally high in both study groups (−13.7 ± 11.9 for MI versus −13.5 ± 16.2 for standard care). Conclusions Adding motivational interviewing counseling to nicotine patch did not increase smoking rate significantly at 26‐week follow‐up for homeless smokers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98308/1/add12140.pd

    Zinc Phosphide Residues in Gray-Tailed Voles (\u3ci\u3eMicrotus canicaudus\u3c/i\u3e) Fed Fixed Particles of a 2% Grain Bait

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    This study measured depelted-carcass residues of zinc phosphide (Zn3P2, CAS # 1314-84-7) in 8 (4 males and 4 females) gray-tailed voles (Microtus canicaudus). Six (3 males and 3 females) voles were confined individually in 1.89 dkl (5 gal) plastic pails that contained 5,2% Zn3P2 steamrolled- oat (SRO) groats; 2 voles (1 male and 1 female) served as analytical (unbaited) controls. Four test voles (3 males and 1female) died within 7.5 h after bait exposure; whereas, 2 test voles showed no signs of toxicosis and were euthanized 7.0 h after bait exposure. Whole carcasses were stored frozen and depelted carcasses were analyzed within 31 days for Zn3P2 residues using a acid-hydrolyzation, gas-chromatographic (GC) method. Analytical controls were euthanized, with carcasses stored and analyzed the same as test voles. A mean (± SD) 4.7 (±0.8) SRO groats were consumed by the test voles; this converted to a mean (±SD) intake of 2.15 (±0.38) mg Zn3P2 and dose of 73.25 mg/kg ( ± 22.95) Zn3P2. The mean (± SD) Zn3P2 residue in the 6 test vole carcasses was 0.42 mg (± 0.68); control carcasses contained \u3c0.009 mg Zn3P2- 3P2 in voles are variable, but typically \u3c 50% of ingested rodenticide and (2) risks of secondary poisoning posed by Zn3P2-baited voles to avian and mammalian predators/scavengers are low due to the relatively high toxic thresholds (\u3e 20 mg/kg) required to affect these species

    Determination of residue levels of the avicide 3-chloro-4-methylaniline hydrochloride in red-winged blackbirds (\u3ci\u3eAgelaius phoeniceus\u3c/i\u3e) by gas chromatography-tandem mass spectrometry

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    The avicide 3‑chloro‑4‑methylanaline hydrochloride (chloro‑p‑toluidine hydrochloride, CPTH, DRC-1339) is used to control pest bird species that damage agricultural crops. A specific and sensitive gas chromatographytandem mass spectrometry method was developed and validated for the determination of CPTH in avian breast muscle, GI tract, kidney, and liver. Tissue samples were extracted with a solution of acidified water and acetonitrile. The sample was made basic and cleaned up with a combination of liquid-liquid partitioning and solid phase extraction. Separation was achieved using a HP-5 ultra-inert GC column (15 M, 0.25 μm film) with detection on a triple quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode. The monitored transition for CPTH was m/z 140.9→106.2 for quantitation and 139.9→105.2 and 139.9→77.2 for confirmation. The linear range was 5 to 5000 ng/mL. The precision for the determination of CPTH in all tissues averaged 7.2% and the accuracy averaged 6.7%. The recovery of CPTH fortified at 5 different levels averaged 101% in liver, 98.8% in GI tract, 92.9% in breast muscle, and 87.9% in kidney. The established method was successfully used to determine CPTH residue levels in red-winged blackbirds exposed to three different doses of CPTH
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