Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Activities of γ-ray emitting isotopes in rainwater from Greater Sudbury, Canada following the Fukushima incident  [PDF]
B. T. Cleveland,F. A. Duncan,I. T. Lawson,N. J. T. Smith,E. Vazquez-Jauregui
Physics , 2012,
Abstract: We report the activity measured in rainwater samples collected in the Greater Sudbury area of eastern Canada on 3, 16, 20, and 26 April 2011. The samples were gamma-ray counted in a germanium detector and the isotopes 131I and 137Cs, produced by the fission of 235U, and 134Cs, produced by neutron capture on 133Cs, were observed at elevated levels compared to a reference sample of ice-water. These elevated activities are ascribed to the accident at the Fukushima Dai-ichi nuclear reactor complex in Japan that followed the 11 March earthquake and tsunami. The activity levels observed at no time presented health concerns.
Natural Radium Isotopes in Particulate and Dissolved Phases of Seawater and Rainwater at the West Coast Peninsular Malaysia Caused by Coal-Fired Power Plant  [PDF]
Nik Azlin Nik Ariffin
EnvironmentAsia , 2010,
Abstract: The concentration levels of natural radium isotopes such as 226Ra and 228Ra were measured in the atmospheric samples including rainwater, total suspended solids (TSSrw) and marine environment samples collected around the Kapar coal-fired power plant from September 2006 to February 2008. Activity concentration of 228Ra and 226Ra in rainwater showed the higher concentrations compared to the seawater. The mean activities of 226Ra and 228Ra in rainwater at Kapar were 20.45±4.50 mBq/L and 74.82±25.38 mBq/L, respectively. Meanwhile the levels in total suspended solids (TSSrw) of rainwater showed 226.99±52.57 Bq/kg for 226Ra and 439.92±186.17 Bq/kg for 228Ra. The measurements of radium isotopes concentration in rainwater at coal-fired power plant in Kapar are found in relation to their sources and application as tracers in lower atmosphere. The mean value of pH in rainwater during this study is pH 5.51 slightly acidic as lowest value for the standard of clean rainwater. Radium in seawater also strong adsorption onto total suspended solids with the distribution coefficient, Kd values of 228Ra and 226Ra ranged from 0.054 × 104 to 163.90 × 104 L/g and between 0.49 × 104 to 191.54 × 104 L/g, respectively.
Estimating Soil Hydraulic Parameters Characterizing Rainwater Infiltration and Runoff Properties of Dryland Floodplains  [PDF]
Sabelo S. W. Mavimbela, Leon D. van Rensburg
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2019, DOI: 10.4236/cweee.2019.81002

The two-layered (0 - 50 and 50 - 250 mm) surface horizon hydraulic parameters of three dryland floodplain soil-types under aquafer water management in Postmasburg, Northern Cape Province of South Africa were estimated with HYDRUS-1D model. Time dependent water infiltration measurements at 30 and 230 mm depths from simulated rainfalls on undisturbed 1 m2 small plots with intensities of 1.61 (high), 0.52 (medium) and 0.27 (low) mm·min-1, were minimised using a two-step inversion. Firstly, separate optimisation of the van Genuchten-Mualem model parameters for the two surface-horizon layers and secondly, simultaneous optimisation for the joint two-layered horizon with first step optimal parameters entered as initial values. The model reproduced transient water-infiltration data very well with the Nash-Sutcliffe model efficiency coefficient (NSE) of 0.99 and overestimated runoff (NSE; 0.27 to 0.98). The upper surface horizon had highly optimised and variable parameters especially θs and Ks. Optimal

A technology of rainwater resource utilization in green residential districts

He Qiang,Chai Hongxiang,

环境工程学报 , 2008,
Abstract: It has been a trend that green residential district is designed with the bionomics principle, and more attention are paid to water saving and the utilization of water resource than before. The comprehensive utilization of rainwater resource includes the collection and decentralized process of rainwater, the collection and centralized process of rainwater, the rainwater infiltration. The technology is less investment and easily managed, good results in rainwater treatment. The technology can provide reference for the construction of rainwater resource comprehensive utilization in green residential districts.
Reducing non-point source pollution with enhancing infiltration
MU Huan-zhen,ZHENG Tao,HUANG Yan-chu,ZHANG Chun-ping,LIU Chen,
MU Huan-zhen
,ZHENG Tao,HUANG Yan-chu,ZHANG Chun-ping,LIU Chen

环境科学学报(英文版) , 2006,
Abstract: The rainfall system was set up on a slope land, which was used with some materials to enhance soil infiltration. The results showed that it was effective to enhance the infiltration of rainwater in soil and reduce the pollutants of surface runoff. After t
Stable Isotopes Studies in the Urucu Oil Province, Amazon Region, Brazil  [PDF]
Eliene Lopes de Souza, Paulo Galvao, Roseli de Almeida, Cleane Pinheiro, Marcus Baessa, Marcio Cabral
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.73011
Abstract: The study area is the Urucu Oil Province, Municipality of Coari, State of Amazonas, Brazil. This research represents a contribution to the hydrogeological knowledge in the northern region of Brazil, particularly in the central part of the Amazon rainforest, where researches on isotopic are still incipient. The primary goal was to determine, by stable isotopes 18O and 2H measurements, interrelationships between surface water and groundwater, in order to understand the origin and mechanisms of groundwater recharge and discharge. For this, samples of rainwater, superficial water and groundwater were collected between June 2008 and May 2009 for stable isotopic analyzes. This understanding is important in cases of eventual contaminations of the area, which could degrade the water resources. The results show that the superficial waters are typically light waters and have meteoric origin, and the groundwater recharge is by direct rainfall infiltration with primary evaporation before reaching the groundwater table in the Icá-Solimoes Aquifer System. The isotopic signatures similarities between groundwater and superficial waters indicate both waters’ contributions in the streams and, therefore, in the Urucu river.
Biography of John Rainwater  [PDF]
Robert R. Phelps
Mathematics , 2003,
Abstract: The following paragraphs will describe the origins of John Rainwater, the impact of his work, the motivations for various parts of it and the prospects for his future.
Changes in Total Dissolved Solids Concentration during Infiltration through Soils (Rain, Fresh Groundwater and Treated Wastewater)  [PDF]
Alsharifa Hind Mohammad, Ghaidaa Abdullat, Khitam Alzughoul
Journal of Environmental Protection (JEP) , 2017, DOI: 10.4236/jep.2017.81004
Abstract: Water quality deterioration took place during infiltration process. Quality of the source water, climate conditions and amounts of added water are the major role players of the differentiation measures. Treated wastewater, rainwater and fresh groundwater were described within this study. It was found that the rainwater has an aggressive behavior with a high ability to dissolve soil salts. The amounts of Total Dissolved Solids (TDS) increase with infiltration process. Electrical conductivity (EC) increased by 600%. Plotting the fresh groundwater to the same conditions and experiment reflects the ability of this water to dissolve soil salts and increases the TDS by increasing the EC by a percentage of around 200%; while applying lower quality of water, the percentage of the EC of the treated wastewater increases to about 230% for the depth of 20 cm, which indicates the accumulation of the salts within this part of the soil, which leads to the deterioration of the soil quality, and decreases to about 160% for a depth of 60 cm. This differentiation could be a result of low permeability soils which tend to accumulate salts as a result of evaporation and then increase the salinity in the topsoil. Dissolution and plant uptake in the infiltrated take of minerals save the soil’s water from evaporation and do not allow salts to concentrate in soils. Moreover, plant uptake of soil water chemicals causes a decrease in some salt concentrations such as NO3, PO4, K, Na, and Cl and may conserve others.
Artificial biological soil crust property and potential for rainwater harvest

ZHOU Gui-Lian,ZHANG Wan-Jun,

中国生态农业学报 , 2012,
Abstract: It is important to collect limited rainwater for agricultural and domestic use in arid and semiarid areas. Rainwater harvesting systems used for collection, storage and purification of rainwater are critical for rainwater utilization. Materials used in building the surfaces of rainwater harvesting plots determine the efficiency of rainwater harvesting system as they affect the hydrological characteristics of the plot surfaces. This paper discussed the potential and feasibility of artificially cultivated biological soil crusts (BSCs) as surface materials of rainwater harvesting plots. It investigated the effects of artificial BSCs on soil physical properties and infiltration and also on the efficiency of rainwater harvest. The results showed that the surface soil (0~1 cm) with artificial BSCs contained more tiny particles and less coarse particles than natural soil. However, no significant difference was noted in bulk density of 0~5 cm soil between artificial BSCs and natural soil. Infiltration rate decreased under artificial BSCs. Initial and stable infiltration rates as well as stable infiltration water volume of BSCs decreased by 59.1%, 44.4% and 50.0%, respectively. The investigation based on rainwater harvesting plots established on 30° slope loamy soil mountain showed that BSCs rainwater runoff efficiency increased. The average runoff efficiency of BSCs rainwater harvesting plot was 60.86% during six runoff events in May to August 2005. BSCs rainwater harvesting plot increased runoff efficiency over that of natural soil by 23.0%. Benefit analysis showed that BSCs not only increased runoff efficiency, but also longer-lasting with significantly less runoff sediment. BSCs were therefore recommended as potential green materials for rainwater harvest.
Target heart rate to determine the normal value of coronary flow reserve during dobutamine stress echocardiography
Ezequiel H Forte, Maria G Rousse, Jorge A Lowenstein
Cardiovascular Ultrasound , 2011, DOI: 10.1186/1476-7120-9-10
Abstract: A total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography.The feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%). Mean CFR was 2.67 at de end of dobutamine test.There was an excellent concordance between delta HR (difference between baseline HR and maximum HR) and the increase in the CFR (correlation coefficient 0.84). In this sense, we found that when HR increased by 50 beats, CFR was ≥ 2 (CI 93-99.2%). In addition, 96.4% of patients reached a CFR ≥ 2 (IC 91.1 - 99%) at 75% of their predicted maximum heart rate.We found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm from baseline HR or at least 75% of the maximum predicted heart rate to consider sufficient the test for the analysis of CFR.Coronary atherosclerosis is a highly prevalent disease in our population, and not just the expression of an anatomic condition [1]. The functional status of this affection should be thoroughly analyzed. The valuable information provided by coronary angiography is not enough to study the functional status of atherosclerotic disease [2]. In these sense, several studies have demonstrated that management of coronary artery disease based on coronary artery anatomy without considering a functional approach is not superior to medical treatment [3]. Determination of coronary flow reserve (CFR) has been validated and supported by several trials studying coronary artery function [4]. In patients with known or suspected CAD stress echocardiography by semi-simultaneous analysis of wall motion and CFR provi
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.