scholarly journals Factors influencing the distribution of arsenic, fluorine and iodine in shallow groundwater in the oasis zone in the southern margin of the Tarim Basin in Xinjiang, P. R. China

2019 ◽  
Vol 98 ◽  
pp. 09006
Author(s):  
Wei Fan ◽  
Jinlong Zhou ◽  
Yinzhu Zhou ◽  
Yanyan Zeng ◽  
Yunfei Chen
Keyword(s):  
Tarim Basin ◽  
Shallow Groundwater ◽  
Mathematical Statistics ◽  
Test Results ◽  
Chemical Parameters ◽  
Factors Influencing ◽  
Southern Margin ◽  
Groundwater Samples ◽  
High Arsenic

Test results on 302 shallow groundwater samples in an oasis zone in the southern margin of the Tarim Basin in Xinjiang were collected and analysed for a large number of chemical parameters and subjected to mathematical statistics methods. Results show that groundwater with high arsenic, fluorine and iodine concentrations were mainly distributed in the Minfeng County in the central part of the study area. Shallow groundwater in the southern margin of the entire Tarim Basin generally had high fluorine concentrations. The distribution of arsenic and fluorine in groundwater were similar. Intensive evaporation under the arid climatatic condition was an important factor for the enrichment of arsenic, fluorine and iodine in groundwater.

An Investigation of the Quantity, Quality and Sources of Groundwater Seepage into the St. Clair River near Sarnia, Ontario, Canada

1986 ◽  
Vol 21 (3) ◽  
pp. 351-367 ◽  
Author(s):  
Michael Sklash ◽  
Sharon Mason ◽  
Suzanne Scott ◽  
Chris Pugsley
Keyword(s):  
Electrical Conductivity ◽  
River Water ◽  
Organic Contaminants ◽  
Shallow Groundwater ◽  
Seepage Rate ◽  
Groundwater Seepage ◽  
Seepage Meters ◽  
Groundwater Samples ◽  
Hydraulic Gradients ◽  
Unidentified Source

Abstract We used seepage meters and minipiezometers to survey a 100 m by 7 km band of streambed of the St. Clair River near Sarnia, Ontario, Canada, to determine the quantity, quality, and sources of groundwater seepage into the river. The average observed seepage rate, 1.4 x 10−8 m3/s/m2, suggests higher than expected hydraulic conductivities and/or hydraulic gradients in the streambed. We found detectable levels of some organic contaminants in streambed groundwater samples from 1.0 and 1.5 m depths, however , concentrations did not exceed drinking water guidelines. Our isotopic and electrical conductivity data indicate that: (l) the streambed groundwater is not just river water, (2) groundwater from the “freshwater aquifer” at the base of the overburden Is not a significant component of the streambed groundwater, (3) some of the streambed groundwater is partially derived from a shallow groundwater flow system, and (4) an unidentified source of water with low tritium, river water-like δ18O, and very high electrical conductivity, contributes to the streambed groundwater.

scholarly journals High-Arsenic Groundwater in Paleochannels of the Lower Yellow River, China: Distribution and Genesis Mechanisms

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 338
Author(s):  
Chuanshun Zhi ◽  
Wengeng Cao ◽  
Zhen Wang ◽  
Zeyan Li
Keyword(s):  
Yellow River ◽  
The Yellow River ◽  
Rock Interaction ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Groundwater Samples ◽  
Groundwater Systems ◽  
Different Sources ◽  
High Arsenic ◽  
High Arsenic Groundwater

High–arsenic (As) groundwater poses a serious threat to human health. The upper and middle reaches of the Yellow River are well–known areas for the enrichment of high–arsenic groundwater. However, little is known about the distribution characteristics and formation mechanism of high-As groundwater in the lower reach of the Yellow River. There were 203 groundwater samples collected in different groundwater systems of the lower Yellow River for the exploration of its hydrogeochemical characteristics. Results showed that more than 20% of the samples have arsenic concentrations exceeding 10 μg/L. The high-As groundwater was mainly distributed in Late Pleistocene–Holocene aquifers, and the As concentrations in the paleochannels systems (C2 and C4) were significantly higher than that of the paleointerfluve system (C3) and modern Yellow River affected system (C5). The high-As groundwater is characterized by high Fe2+ and NH4+ and low Eh and NO3−, indicating that reductive dissolution of the As–bearing iron oxides is probably the main cause of As release. The arsenic concentrations strikingly showed an increasing tendency as the HCO3− proportion increases, suggesting that HCO3− competitive adsorption may facilitate As mobilization, too. In addition, a Gibbs diagram showed that the evaporation of groundwater could be another significant hydrogeochemical processes, except for the water–rock interaction in the study area. Different sources of aquifer medium and sedimentary structure may be the main reasons for the significant zonation of the As spatial distribution in the lower Yellow River.

Factors Influencing Nut Factor Test Results

2017 ◽  
Author(s):  
Warren Brown ◽  
Stewart Long
Keyword(s):  
Test Results ◽  
Bolted Joint ◽  
Factors Influencing ◽  
Applied Torque ◽  
Bolt Diameter ◽  
Joint Assembly

Nut Factor is used to establish a bolt load for a given applied torque in bolted joint assembly. In previous papers the effects of different factors influencing Nut Factor results were examined, which included the type of anti-seize, bolt and nut material, bolt diameter and amount of anti-seize applied. This paper examines those factors further and then includes additional factors which have been shown to have significant effect on the measured Nut Factor. The knowledge of these factors has been used to adjust the proposed ASTM specification for determining Nut Factor. It is also relevant to application in the field and to ensure that any testing conducted in a laboratory will be applicable in the field.

Characteristics of wind erosion and deposition in oasis-desert ecotone in southern margin of Tarim Basin, China

2014 ◽  
Vol 24 (6) ◽  
pp. 658-673 ◽  
Author(s):  
Donglei Mao ◽  
Jiaqiang Lei ◽  
Fanjiang Zeng ◽  
Zaynulla Rahmutulla ◽  
Cui Wang ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Wind Erosion ◽  
Erosion And Deposition ◽  
Southern Margin

scholarly journals Subterranean Species in Washington, D.C.: Spatial Analysis, Habitat Preferences, & Urban Conservation Implications

2018 ◽  
Vol 1 ◽  
Author(s):  
Jenna Keany
Keyword(s):  
Competitive Exclusion ◽  
Habitat Preferences ◽  
Shallow Groundwater ◽  
Soil Morphology ◽  
Chemical Parameters ◽  
Species List ◽  
Environmental Preferences ◽  
Small Water ◽  
Conservation Implications ◽  
Subterranean Species

Washington, D.C. is home to a remarkable assemblage of troglomorphic amphipods and isopods living in shallow groundwater habitats, the hypotelminorheic. Groundwater from the hypotelminorheic emerges on the surface into low-flowing seepage springs, or “seeps”, which are categorized as having blackened leaves, an underlain layer of clay, a drainage area of less than 10,000 m2, and are situated in slight topographical depressions. Stygobiotic species found in D.C.’s seeps include Crangonyx and Stygobromus amphipods and Caecidotea isopods. One species, Stygobromus hayi, is on the endangered species list and is endemic to the district; however, little is known about their habitat preferences or their distribution. All small water bodies, including rainwater puddles and seepage springs were sampled in national park lands in Southeast D.C. for hypotelminorheic fauna, soil morphology, and water quality indicators such as nitrates, phosphates, radon, pH, DO, and conductivity. Comparing sites with and without stygobionts, all phsysico-chemical parameters were statistically insignificant except for conductivity, which was able to distinguish between stygobiont-rich and stygobiont-poor seeps using logistic regression. Spatially, Crangonyx and Stygobromus amphipods rarely inhabit the same seepage spring, with only three occasions of cohabitation and an expected occurrence of ten. Caecidotea, however, is found in habitats with both amphipods. These results can be explained by either competitive exclusion or the presence of chemical differences in their habitats; however, even if there were some slight differences in their habitats, that still does not exclude competitive exclusion as an explanation. This study highlights new and important findings into the environmental preferences of D.C.’s most cryptic and rare species, and the importance of continued exploration of D.C.’s lesser known park lands.

Features of Educational Motivation and Professional Identity of Russian and Indian Students at the Stage of Admission to the Master's School

2021 ◽  
pp. 31-35
Author(s):  
O. Potapov ◽  
Ritu Ritu
Keyword(s):  
Comparative Analysis ◽  
Professional Identity ◽  
Questionnaire Survey ◽  
Learning Motivation ◽  
Test Results ◽  
Factors Influencing ◽  
Two Samples ◽  
Educational Motivation ◽  
Indian Students

The article is devoted to the study of the peculiarities of educational motivation and professional identity of Russian and Indian students studying in Russia and intending to continue their studies in the magistracy. The use of a comparative analysis based on the test results for two samples, a questionnaire survey, showed the predominance of internal learning motivation and a higher level of professional identity of Indian students compared to students from Russia. The factors influencing the results of measuring educational motivation are indicated. General recommendations on the formation of optimal educational motivation and professional identity of future masters are given.

scholarly journals Multivariate Analysis and Geochemical Signatures of Shallow Groundwater in the Main Urban Area of Chongqing, Southwestern China

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2833
Author(s):  
Si Chen ◽  
Zhonghua Tang ◽  
Jian Wang ◽  
Jialing Wu ◽  
Chang Yang ◽  
...  
Keyword(s):  
Geochemical Modeling ◽  
Shallow Groundwater ◽  
Poor Quality ◽  
Easy Access ◽  
Multivariate Statistical ◽  
Drinking Purposes ◽  
Groundwater Samples ◽  
New Findings ◽  
Group 2 ◽  
Group 1

Hydrogeochemical processes and quality assessment for shallow groundwater are pivotal issues to be solved in many regions over the world due to the easy access of shallow groundwater. In this study, eighty-six water samples were collected from shallow aquifers of Chongqing, China, during July–September 2019. Multivariate statistical techniques, major ion ratios, and geochemical modeling were integrated to investigate hydrogeochemical characteristics and controlling factors. Afterwards, groundwater quality in spatial was classified by entropy-weighted water quality index and geographic information system (GIS) spatial analysis. Groundwater samples were alkaline and possessed high total dissolved solids (TDS) values. Two-group samples were distinguished as mix cations-HCO3-SO4 (group 1) and Ca-Mg-SO4 (group 2) facies. Hydrogeochemical compositions of group 1 samples were dominated by silicate dissolution and ion exchange, while sulfate and calcite dissolution were the main factors influencing the hydrogeochemical characteristics of group 2. The overall quality of groundwater samples varied greatly from excellent quality to extremely poor quality. Group 1 samples were found with excellent and good quality and suitable for drinking purposes. Group 2 samples were all unsuitable for direct drinking purposes as the quality varied from medium to extremely poor, but were spatially limited. Groundwaters with relatively poor quality were due to dissolution of sulfate that were locally enriched in the aquifers. The new findings of this study are expected to provide the reference for future management and sustainable exploitation of groundwater in Chongqing.

Seasonal dynamics of dissolved organic matter in high arsenic shallow groundwater systems

2020 ◽  
Vol 589 ◽  
pp. 125120
Author(s):  
Yijun Yang ◽  
Xiaofang Yuan ◽  
Yamin Deng ◽  
Xianjun Xie ◽  
Yiqun Gan ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Dynamics ◽  
Shallow Groundwater ◽  
Groundwater Systems ◽  
High Arsenic

scholarly journals Impact resistance of external thermal insulation systems

2018 ◽  
Vol 163 ◽  
pp. 08004 ◽  
Author(s):  
Ewa Sudoł ◽  
Dawid Dębski ◽  
Renata Zamorowska ◽  
Barbara Francke
Keyword(s):  
Thermal Insulation ◽  
Impact Resistance ◽  
Experimental Program ◽  
Insulation Material ◽  
Test Results ◽  
Composite Systems ◽  
Factors Influencing ◽  
Insulation Systems ◽  
The Impact ◽  
Fibre Mesh

In the paper the results of an experimental program intended to determine factors influencing the impact resistance of the External Thermal Insulation Composite Systems (ETICS) were presented. For the research the systems based on polystyrene have been chosen. The insulation material was faced with a rendering consisting of base coat reinforced with standard or armored glass fibre mesh and silicone or silicone-silicate binders as finishing coats. The influence of various renderings components was evaluated with respect to resistance to hard body impact and resistance to hail. The test results were discussed in the context of the possible impact level on ETICS in use.

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