594 research outputs found
Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater
We study the relation between surface infiltration and groundwater
recharge during managed aquifer recharge (MAR) with desalinated seawater in
an infiltration pond, at the Menashe site that overlies the northern part of
the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple
scales (up to the scale of the entire pond) by measuring the ponding depth,
sediment water content and groundwater levels, using pressure sensors,
single-ring infiltrometers, soil sensors, and observation wells. During a
month (January 2015) of continuous intensive MAR
(2.45 × 10<sup>6</sup> m<sup>3</sup> discharged to a 10.7 ha area),
groundwater level has risen by 17 m attaining full connection with the pond,
while average infiltration rates declined by almost 2 orders of magnitude
(from ∼ 11 to ∼ 0.4 m d<sup>−1</sup>). This reduction can be
explained solely by the lithology of the unsaturated zone that includes
relatively low-permeability sediments. Clogging processes at the pond-surface
– abundant in many MAR operations – are negated by the high-quality
desalinated seawater (turbidity ∼ 0.2 NTU, total dissolved solids
∼ 120 mg L<sup>−1</sup>) or negligible compared to the low-permeability
layers. Recharge during infiltration was estimated reasonably well by simple
analytical models, whereas a numerical model was used for estimating
groundwater recharge after the end of infiltration. It was found that a
calibrated numerical model with a one-dimensional representative sediment
profile is able to capture MAR dynamics, including temporal reduction of
infiltration rates, drainage and groundwater recharge. Measured infiltration
rates of an independent MAR event (January 2016) fitted well to those
calculated by the calibrated numerical model, showing the model validity. The
successful quantification methodologies of the temporal groundwater recharge
are useful for MAR practitioners and can serve as an input for groundwater
flow models
Pipes to Earth's subsurface: the role of atmospheric conditions in controlling air transport through boreholes and shafts
Understanding air exchange dynamics between underground
cavities (e.g., caves, mines, boreholes, etc.) and the atmosphere is
significant for the exploration of gas transport across the
Earth–atmosphere interface. Here, we investigated the role of atmospheric
conditions in controlling air transport inside boreholes using in situ field
measurements. Three geometries were explored: (1) a narrow and deep shaft
(0.1 m wide and 27 m deep), ending in a large underground cavity; (2) the same
shaft after the pipe was lowered and separated from the cavity; and (3) a deep
large-diameter borehole (59 m deep and 3.4 m wide). Absolute humidity was found to be a
reliable proxy for distinguishing between atmospheric and cavity air masses
(mainly during the winter and spring seasons) and thus to explore air transport
through the three geometries. Airflow directions in the first two
narrow-diameter geometries were found to be driven by changes in barometric
pressure, whereas airflow in the large-diameter geometry was correlated
primarily with the diurnal cycles of ambient atmospheric temperature. CO2
concentrations of ∼ 2000 ppm were found in all three
geometries, indicating that airflow from the Earth's subsurface into the
atmosphere may also be significant in the investigation of greenhouse gas emissions.</p
Tailored carrier/bacteria technology for rehabilitation of areas with pesticide-containing pollution – AQUAREHAB WP2
Postprint (published version
Acute hypoxemia and vascular function in healthy humans.
Endothelium-dependent flow mediated dilation (FMD) and endothelium-independent dilation (GTN) are impaired at high altitude (5050 m), and FMD is impaired following acute exposure (<60-minutes) to normobaric hypoxia equivalent to ∼5050 m (∼FI O2 = 0.11). Whether glyceryl trinitrate (GTN)-induced dilation is impaired acutely, and whether FMD is impaired during milder hypoxia is unknown. Therefore, we assessed brachial FMD at baseline and following 30-minutes of mild (74 ± 2 mmHg PET O₂) and moderate (50 ± 3 mmHg PET O₂) normobaric hypoxia (n = 12) or normoxia (time-control trial; n = 10). We also assessed GTN-dilaiton following the hypoxic FMD tests and in normoxia on a separate control day (n = 8). Compared to normoxic baseline, reduction during mild and moderate hypoxic exposure were evident in FMD (mild vs moderate: -1.2 ± 1.1% vs. -3.1 ± 1.7%; P = 0.01) and GTN-dilation (-2.1 ± 1.0 vs. -4.2 ± 2.0; P = 0.01); the decline in FMD and GTN-dilation were greater during moderate hypoxia (P < 0.01). When allometrically corrected for baseline diameter and FMD shear rate under the curve (SRAUC ), relative FMD was attenuated in both conditions (mild vs moderate: 0.6 ± 0.9% vs. 0.8 ± 0.7%; P ≤ 0.01). Following 30-minutes of normoxic time-control, FMD was reduced (-0.6 ± 0.3%; P = 0.02). In summary, there was a graded impairment in FMD during mild and moderate hypoxic exposure, which appears to be influenced by shear patterns and incremental declines in smooth muscle vasodilator capacity (impaired GTN-dilation). Our findings from the normoxic controls study, suggest the decline in FMD in acute hypoxia also appears to be influenced by 30-minutes of supine rest/inactivity. This article is protected by copyright. All rights reserved
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Ultrafiltration evaluation with depleted uranium oxide
Scientists at the Los Alamos National Laboratory Plutonium Facility are using electrodissolution in neutral to alkaline solutions to decontaminate oralloy parts that have surface plutonium contamination. Ultrafiltration of the electrolyte stream removes precipitate so that the electrolyte stream to the decontamination fixture is precipitate free. This report describes small-scale laboratory ultrafiltration experiments that the authors performed to determine conditions necessary for full-scale operation of an ultrafiltration module. Performance was similar to what they observed in the ferric hydroxide system. At 12 psi transmembrane pressure, a shear rate of 12,000 sec{sup {minus}1} was sufficient to sustain membrane permeability. Ultrafiltration of uranium(VI) oxide appears to occur as easily as ultrafiltration of ferric hydroxide. Considering the success reported in this study, the authors plan to add ultrafiltration to the next decontamination system for oralloy parts
Managed aquifer recharge with reverse-osmosis desalinated seawater: modeling the spreading in groundwater using stable water isotopes
The spreading of reverse-osmosis desalinated seawater (DSW) in the Israeli
coastal aquifer was studied using groundwater modeling and stable water
isotopes as tracers. The DSW produced at the Hadera seawater reverse-osmosis
(SWRO) desalination plant is recharged into the aquifer through an infiltration pond at the managed
aquifer recharge (MAR) site of Menashe, Israel. The distinct difference in isotope composition between DSW
(δ18O  =  1.41 ‰;
δ2H  =  11.34 ‰) and the natural groundwater
(δ18O  =  −4.48 ‰ to −5.43 ‰;
δ2H  =  −18.41 ‰ to −22.68 ‰) makes
the water isotopes preferable for use as a tracer compared to widely used
chemical tracers, such as chloride. Moreover, this distinct difference can be
used to simplify the system to a binary mixture of two end-members:
desalinated seawater and groundwater. This approach is validated through a
sensitivity analysis, and it is especially robust when spatial data of stable
water isotopes in the aquifer are scarce. A calibrated groundwater flow and
transport model was used to predict the DSW plume distribution in the aquifer
after 50 years of MAR with DSW. The results suggest that after 50 years,
94 % of the recharged DSW was recovered by the production wells at the
Menashe MAR site. The presented methodology is useful for predicting the
distribution of reverse-osmosis desalinated seawater in various downstream
groundwater systems.</p
Why Social Enterprises Are Asking to Be Multi-stakeholder and Deliberative: An Explanation around the Costs of Exclusion.
The study of multi-stakeholdership (and multi-stakeholder social enterprises in particular) is only at the start. Entrepreneurial choices which have emerged spontaneously, as well as the first legal frameworks approved in this direction, lack an adequate theoretical support. The debate itself is underdeveloped, as the existing understanding of organisations and their aims resist an inclusive, public interest view of enterprise. Our contribution aims at enriching the thin theoretical reflections on multi-stakeholdership, in a context where they are already established, i.e. that of social and personal services.
The aim is to provide an economic justification on why the governance structure and decision-making praxis of the firm needs to account for multiple stakeholders. In particular with our analysis we want: a) to consider production and the role of firms in the context of the “public interest” which may or may not coincide with the non-profit objective; b) to ground the explanation of firm governance and processes upon the nature of production and the interconnections between demand and supply side; c) to explain that the costs associated with multi-stakeholder governance and deliberation in decision-making can increase internal efficiency and be “productive” since they lower internal costs and utilise resources that otherwise would go astray.
The key insight of this work is that, differently from major interpretations, property costs should be compared with a more comprehensive range of costs, such as the social costs that emerge when the supply of social and personal services is insufficient or when the identification of aims and means is not shared amongst stakeholders. Our model highlights that when social costs derived from exclusion are high, even an enterprise with costly decisional processes, such as the multistakeholder, can be the most efficient solution amongst other possible alternatives
Identification of highly brominated analogues of Q1 in marine mammals
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Environmental Pollution 144 (2006): 336-344, doi:10.1016/j.envpol.2005.10.052.Three novel halogenated organic compounds (HOCs) have been identified in the blubber of marine mammals from coastal New England with the molecular formulae C9H3N2Br6Cl, C9H3N2Br7, and C9H4N2Br5Cl. They were identified using high and low resolution electron ionization (EI) and electron capture negative ionization (ECNI) gas chromatography mass spectrometry (GCMS) and appear to be highly brominated analogues of Q1, a heptachlorinated HOC that has been suspected to be naturally-produced. These new compounds were found in Atlantic white sided dolphin (Lagenorhynchus acutus), bottlenose dolphin (Tursiops truncatus), common dolphin (Delphinus delphis), Risso’s dolphin (Grampus griseus), harbor porpoise (Phocoena phocoena), beluga whale (Delphinapterus leucas), fin whale (Balaenoptera physalus), grey seal (Halichoerus grypus), harp seal (Phoca groenlandica) and a potential food source (Loligo pealei) with concentrations as high as 2.7 μg/g (lipid weight). The regiospecificity of C9H3N2Br6Cl is suggestive of a biogenic origin. Debromination of C9H3N2Br6Cl may be significant in the formation of C9H4N2Br5Cl.This work was supported by the National Science Foundation (OCE-0221181), the Woods Hole Oceanographic Institution (WHOI) Ocean Life Institute, the Postdoctoral Scholar Program at WHOI (with funding from The Camille and Henry Dreyfus Foundation, Inc. and The J. Seward Johnson Fund) (ELT) and The Island Foundation, Inc (BEP)
The role of health in development
The basic needs strategy of development is directed toward helping poor nations meet requirements for adequate food, shelter, sanitation, health, and education; thus, health becomes an objective of development. At the same time, a basic needs strategy is most effective when viewed as a means to increase individual and national productivity, not merely as a welfare services program. Expenditures on health are considered as an investment in human resources, contributing to productive capacity, but empirical studies on the contribution of health to per capita economic growth are largely anecdotal, marred by poor design and insufficient data. A similarly perplexing problem is the extent to which improved health is the result of specific health program interventions as compared to improved economic and social conditions. Both are important, but their relative importance differs from country to country and from era to era. Better data and analysis are necessary, not only to elucidate the interrelationships between health and development, but to measure the costs and benefits of specific health interventions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23226/1/0000159.pd
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