scholarly journals Estimation of direct evaporation from groundwater by using lysimeters in the Salar de Pedernales basin, Chilean Altiplano

2020 ◽  
Vol 30 ◽  
pp. 1-14
Author(s):  
Reynaldo Payano-Almánzar ◽  
Dimitri Dionizis
Keyword(s):  
Numerical Model ◽  
Water Balance ◽  
Shallow Groundwater ◽  
Arid Zones ◽  
Salt Flats ◽  
Chilean Altiplano ◽  
Semi Arid ◽  
Model Water

In this research an estimation of the evaporation discharges from shallow groundwater in the Salar de Pedernales basin is made, using the lysimeter methodology. The analysis performed shows values between 1400 L·s-1 and 1900 L·s-1 with an uncertainty of error of 5% with respect to the average and between 11% and 47% in relation to the minimum and maximum values which can be compared by other studies where different tools have been used to calculate evaporation, such as: chamber, numerical model, water balance, Bowen relationships, Eddy correlations, and evaporation curves vs. altitude. The results confirm that lysimeters are appropriate tools for the determination of soil evapotranspiration and evaporation from shallow groundwater, whose components are key in the hydrology of endorheic basins, arid and semi-arid zones, for the management of protected natural spaces such as salt flats, waterholes, fertile plains, and bofedales.

Water balance in swelling materials: some comments

Soil Research ◽  
1997 ◽  
Vol 35 (5) ◽  
pp. 1143 ◽  
Author(s):  
D. E. Smiles
Keyword(s):  
Water Balance ◽  
Water Content ◽  
Material Balance ◽  
Physical Space ◽  
Clay Soils ◽  
Acid Sulfate ◽  
Retention Ponds ◽  
Material Space ◽  
Semi Arid

Materials ranging from wet tailings in retention ponds through potentially acid sulfate sediments in humid marine environments to clay soils in semi-arid climates shrink and swell with change in water content. This paper discusses the formulation and determination of material balance in such swelling and cracking materials. Significant errors and their likely magnitudes are identified when these estimates are based in physical space, as opposed to material space. Ways in which this problem might be dealt with are discussed.

Understanding co-occurrence and mobility of uranium and arsenic sources in groundwater flow systems in semi-arid zones in the Mexican Altiplano

2020 ◽  
Author(s):  
Dario del Angel Cauich Kau ◽  
Antonio Cardona Benavides ◽  
Javier Castro Larragoitia ◽  
Thomas R. Rüde
Keyword(s):  
Water Supply ◽  
Volcanic Rocks ◽  
Shallow Groundwater ◽  
Permissible Limit ◽  
World Health ◽  
Arid Zones ◽  
Climatic Trend ◽  
The World ◽  
Flow Systems ◽  
Semi Arid

<p>Groundwater is the main source of water supply for the population in the semi-arid zones in Mexico. In this climatic condition, evapotranspiration originated from phreatophytes and evaporation is an important component of the water budget for shallow aquifers. Arsenic and uranium are trace elements generally found naturally in groundwater, as they can originate from the interaction of groundwater with igneous rocks and sediments. Despite their generally different redox properties and transport behavior in groundwater, they show a relationship (a potential common geogenic source).</p><p>This research addresses the effect of groundwater evapotranspiration on arsenic and uranium concentrations in different flow systems in Villa de Reyes and Cerritos basins in the Mexican Altiplano. The former is mainly characterized by volcanic rocks and the latter is located in an area dominated by limestone yet connected to felsic, partially mineralized rocks by a complex karst system. According to the Mexican legislation, the permissible limit for arsenic in water for human use and consumption is 25 µg/L; however, it does not consider a permissible limit for uranium. German legislation as well as the World Health Organization (WHO) established 10 µg/L.</p><p>The concentrations of arsenic and uranium found in the rocks in the two sites were in the range of 1.8-65 and 0.7-19 mg/kg respectively, in which it is observed that some sites exceed the local background values. The high arsenic and uranium concentrations have been found in felsic intrusive bodies and rhyolites in both sites. This confirmed an earlier study identifying rhyolitic lava flows and rhyolitic glass within the Villa de Reyes Basin as main arsenic and uranium geogenic sources.</p><p>The arsenic and uranium concentrations in groundwater at the Villa de Reyes basin showed that 100% of the groundwater samples were within the Mexican Legislation for arsenic but in the case of uranium, 6% of the samples were above the German and WHO regulations. The shallow granular aquifer in the Cerritos Basin, the groundwater values gave different results. Only 74% of the sites were within the Mexican regulation for arsenic and 36% above the critical value. For uranium, 90% of the sites were within the German and WHO regulations.</p><p>In addition, isotopic data (environmental stable isotopes from the water molecule <sup>2</sup>H and <sup>18</sup>O) showed that shallow groundwater in the Cerritos Basin was fractioned by evapotranspiration processes. These led to the observed high concentrations of especially arsenic as was also supported by geochemical modelling.</p><p>Especially as the climatic trend predicted higher temperatures for central to north Mexico, enrichment of arsenic and other potentially toxic elements by evapotranspiration will be encouraged. Increasing population requires a good quality water supply, understanding the behavior of arsenic and uranium in these areas may be useful for similar regions not only in Mexico but also in similar areas around the world.</p>

scholarly journals Apparent Young’s Modulus of the Adhesive in Numerical Modeling of Adhesive Joints

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Kamil Anasiewicz ◽  
Józef Kuczmaszewski
Keyword(s):  
Numerical Model ◽  
Young’S Modulus ◽  
Adhesive Joint ◽  
Young's Modulus ◽  
Precise Determination ◽  
Adhesive Joints ◽  
Experimental Conditions ◽  
Element Simulation ◽  
Joint Material

This article is an evaluation of the phenomena occurring in adhesive joints during curing and their consequences. Considering changes in the values of Young’s modulus distributed along the joint thickness, and potential changes in adhesive strength in the cured state, the use of a numerical model may make it possible to improve finite element simulation effects and bring their results closer to experimental data. The results of a tensile test of a double overlap adhesive joint sample, performed using an extensometer, are presented. This test allowed for the precise determination of the shear modulus G of the cured adhesive under experimental conditions. Then, on the basis of the research carried out so far, a numerical model was built, taking the differences observed in the properties of the joint material into account. The stress distribution in a three-zone adhesive joint was analyzed in comparison to the standard numerical model in which the adhesive in the joint was treated as isotropic. It is proposed that a joint model with three-zones, differing in the Young’s modulus values, is more accurate for mapping the experimental results.

Deuterium-excess determination of evaporation to inflow ratios of an alpine lake: Implications for water balance and modeling

2016 ◽  
Vol 31 (5) ◽  
pp. 1034-1046 ◽  
Author(s):  
Jiangpeng Cui ◽  
Lide Tian ◽  
Trent W. Biggs ◽  
Rong Wen
Keyword(s):  
Water Balance ◽  
Alpine Lake ◽  
Deuterium Excess

scholarly journals Use of recent geoid models to estimate mean dynamic topography and geostrophic currents in South Atlantic and Brazil Malvinas confluence

2012 ◽  
Vol 60 (1) ◽  
pp. 41-48
Author(s):  
Alexandre Bernardino Lopes ◽  
Joseph Harari
Keyword(s):  
Numerical Model ◽  
Large Scale ◽  
Singular Spectrum Analysis ◽  
Satellite System ◽  
South Atlantic ◽  
Dynamic Topography ◽  
Geostrophic Currents ◽  
Mean Dynamic Topography ◽  
Level Model

The use of geoid models to estimate the Mean Dynamic Topography was stimulated with the launching of the GRACE satellite system, since its models present unprecedented precision and space-time resolution. In the present study, besides the DNSC08 mean sea level model, the following geoid models were used with the objective of computing the MDTs: EGM96, EIGEN-5C and EGM2008. In the method adopted, geostrophic currents for the South Atlantic were computed based on the MDTs. In this study it was found that the degree and order of the geoid models affect the determination of TDM and currents directly. The presence of noise in the MDT requires the use of efficient filtering techniques, such as the filter based on Singular Spectrum Analysis, which presents significant advantages in relation to conventional filters. Geostrophic currents resulting from geoid models were compared with the HYCOM hydrodynamic numerical model. In conclusion, results show that MDTs and respective geostrophic currents calculated with EIGEN-5C and EGM2008 models are similar to the results of the numerical model, especially regarding the main large scale features such as boundary currents and the retroflection at the Brazil-Malvinas Confluence.

scholarly journals The demography of desert Australia

2008 ◽  
Vol 30 (1) ◽  
pp. 29 ◽  
Author(s):  
Dominic Brown ◽  
John Taylor ◽  
Martin Bell
Keyword(s):  
Economic Policy ◽  
Arid Zone ◽  
Policy Implications ◽  
Population Projections ◽  
Research Centre ◽  
Arid Zones ◽  
Demographic Information ◽  
The Impact ◽  
First Time ◽  
Semi Arid

In recent years, with the formation of organisations such as the Desert Knowledge Cooperative Research Centre, social science interest in the Australian desert has re-surfaced with a research emphasis that is focused on creating sustainable futures for the region. One consequence of this is a demand for detailed demographic information to allow an assessment of different quanta of need in social and economic policy, and for assessment of the impact of these in environmental policy. However, demographic analysis on human populations in the desert to date has attracted very little research attention. In this paper we begin to address this lack of analysis by focusing on the populations, both aboriginal and non-aboriginal, of the arid and semi-arid zones of Australia. We extend earlier analysis by including for the first time demographic information on the semi-arid as well as the arid zone to establish the spatial pattern of population growth within the whole desert area drawing attention to the resulting settlement structure as an outcome of prevailing social, cultural and economic conditions. By examining population structure and demographic components of population change we also present for the first time population projections for the semi-arid zone and, therefore, in combination with the arid zone, for the entire Australian desert. All of this provides a basis for considering social and economic policy implications and the nature of underlying processes that drive change in this region.

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