Average Electrical Conductivity Values Research Articles

Evaluation of the Quality of Groundwater for Irrigation Purposes in Karur District, Tamilnadu, South India

This work aimed to evaluate several physicochemical characteristics in irrigation water over acceptable criteria. The research for this paper was conducted during the construction of the Karur District in the state of Tamil Nadu in South India. In order to conduct the investigation of the water's quality, 201 open-air wells provided the source for the water samples. The field survey design was utilized and complemented by laboratory testing to analyze the levels of physicochemical parameters in both seasons (pre-monsoon and post-monsoon seasons) for groundwater and water bodies. Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), Magnesium Adsorption Ratio (MAR), Kelly Index (KI), pH, Electric Conductivity (EC), and Total Dissolved Solids (TDS) were the physical and chemical parameters that were analyzed. The average electrical conductivity values were relatively high, despite our studied samples being within the allowable range for irrigation water quality.

Preparation of HfCxN1-x Nanoparticles Derived from a Multifunction Precursor with Hf-O and Hf-N Bonds.

HfCxN1-x nanoparticles were synthesized using the urea-glass route, employing hafnium chloride, urea, and methanol as raw materials. The synthesis process, polymer-to-ceramic conversion, microstructure, and phase evolution of HfCxN1-x/C nanoparticles were thoroughly investigated across a wide range of molar ratios between the nitrogen source and the hafnium source. Upon annealing at 1600 °C, all precursors demonstrated remarkable translatability to HfCxN1-x ceramics. Under high nitrogen source ratios, the precursor exhibited complete transformation into HfCxN1-x nanoparticles at 1200 °C, with no observed presence of oxidation phases. In comparison to HfO2, the carbothermal reaction of HfN with C significantly reduced the preparation temperature required for HfC. By increasing the urea content in the precursor, the carbon content of the pyrolyzed products increased, leading to a substantial decrease in the electrical conductivity of HfCxN1-x/C nanoparticle powders. Notably, as the urea content in the precursor increased, a significant decrease in average electrical conductivity values was observed for the R4-1600, R8-1600, R12-1600, and R16-1600 nanoparticles measured at a pressure of 18 MPa, yielding values of 225.5, 59.1, 44.8, and 46.0 S·cm-1, respectively.

Cell-to-Cell Adhesion and Electrical Parameters of Murine Embryo Membranes After Cryopreservation by Vitrification

In this work, we have studied the impact of various stages of cryopreservation by vitrification in ethylene glycolsucrose medium on plasma membranes adhesive properties of 8-cell murine embryos and their specific electrical conductivity. Embryos were divided into the following experimental groups: the control, group 1 (incubation in vitrification medium) and group 2 (complete cycle of cryopreservation). The embryo exposure to vitrification medium did not affect their ability to cell-to-cell adhesion. After a complete cycle of cryopreservation, no embryo adhesion was observed. Electrical conductivity of embryo membranes was determined using the pulsed conductometry. After incubation in vitrification medium, their resistance to electric pulse was shown to decrease, that was manifested in the phenomenon of irreversible electric breakdown. The average values of electrical conductivity varied within the following ranges: ((12.1 ± 1.5)...(55.5 ± 2.6)), ((28.7 ± 5.7)...(44.± 8.9)), ((31.0 ± 9.3)...(87.9 ± 26.1)) μS/cm in the control, groups 1 and 2, respectively. These findings may be explained by appearance of first structural disorders in lipid bilayer of embryo membranes even at the stage of their incubation in vitrification medium. The lack of adhesive properties of blastomeres after vitrification-warming testified to a damage to the membrane adhesion proteins.

Anthropogenic depletion of Iran’s aquifers

Global groundwater assessments rank Iran among countries with the highest groundwater depletion rate using coarse spatial scales that hinder detection of regional imbalances between renewable groundwater supply and human withdrawals. Herein, we use in situ data from 12,230 piezometers, 14,856 observation wells, and groundwater extraction points to provide ground-based evidence about Iran's widespread groundwater depletion and salinity problems. While the number of groundwater extraction points increased by 84.9% from 546,000 in 2002 to over a million in 2015, the annual groundwater withdrawal decreased by 18% (from 74.6 to 61.3 km3/y) primarily due to physical limits to fresh groundwater resources (i.e., depletion and/or salinization). On average, withdrawing 5.4 km3/y of nonrenewable water caused groundwater tables to decline 10 to 100 cm/y in different regions, averaging 49 cm/y across the country. This caused elevated annual average electrical conductivity (EC) of groundwater in vast arid/semiarid areas of central and eastern Iran (16 out of 30 subbasins), indicating "very high salinity hazard" for irrigation water. The annual average EC values were generally lower in the wetter northern and western regions, where groundwater EC improvements were detected in rare cases. Our results based on high-resolution groundwater measurements reveal alarming water security threats associated with declining fresh groundwater quantity and quality due to many years of unsustainable use. Our analysis offers insights into the environmental implications and limitations of water-intensive development plans that other water-scarce countries might adopt.

Assessment of Groundwater Geochemistry of Vel River basin, Western Maharashtra, India

To study the chemistry of major ion in groundwater from Vel (Velu) River basin, sixty (60) samples of dug wells and bore wells were collected and analyzed using standard techniques given by APHA. It shows order of dominance for cations, Na+ > Ca2+ > Mg2+ > K+ and in anionic concentration as HCO3- > Cl- > SO42- in groundwater. The pH of groundwater is slightly alkaline (range: pH 7.0 - 8.1), while average values of Electrical Conductivity (EC) is about 2641 µS/cm indicating high mineralization of groundwater. In general, the cationic concentration (Na+, K+, Ca2+ and Mg2+) of the groundwater increase in the downstream side (from Northwest to South east), suggesting geological control on the composition of groundwater while highest concentration is in lower part of the basin are generally associated with the high salinity. In the major anions, bicarbonate (HCO3-) is higher due to rock-water interaction. Average value of chloride is about of 235 mg/L due to discharge zones along with anthropogenic activities. The geochemical data plotted on Piper Trilinear Diagram is showing dominant hydro-chemical facies: Ca2++Mg2+, Na++ K+, Cl-+ SO42- -HCO3- found in 83.3 % samples indicating the alkaline earth exceeding the alkalis and the strong acids exceeds the weak acids. The pH, Total Hardness (TH) and Magnesium (Mg2+) of the samples show more proportion of samples falling above desirable limit. Otherwise the quality of groundwater is good for drinking. The irrigation indices like SAR, KR and SSP were considered to evaluate groundwater suitability for irrigation. Comparing with SAR parameter all samples are excellent to good for irrigation. In SSP, 33.3 % samples are within permissible, while 66.6% samples are doubtful for irrigation purpose. In KR almost all samples (excluding 04 samples in lower side of basin) are suitable for irrigation. So, variations in climate, geology with anthropogenic activities are modifying the groundwater geochemistry of Vel River Basin.

Assessment of the spatial variability of apparent electrical conductivity in a tile drained catchment in Fensholt subcatchment, Jutland, Denmark for improved small-scale prediction of highly reducing areas

The implementation of a targeted, site-specific approach on reducing the nitrogen load from agriculture requires fine-scale assessment of soil heterogeneity. In this study, the soil heterogeneity was described through the spatial heterogeneity of the apparent electrical conductivity values (ECa) and its implications to the patterns of redox potential values (Eh) in an intensely tile drained agricultural area. Piezometers and platinum-tipped redox probes for water level and Eh measurements were installed in transects along the assumed subsurface lateral water flow direction at different depths overlying the tile drains. Water level and Eh were determined from February to August 2017. A statistical analysis of the average ECa and slope measurements of each transect showed that they could be classified into four operational soil combinations (SC): high ECa, low slope (SC-1), low ECa, low slope (SC-2), high ECa, high slope (SC-3), low ECa, high slope (SC-4). A significant correlation between the inverted electrical conductivity (EC) values, clay and soil organic carbon (SOC) content suggested that the EC correlates with clay content. The high clay percentage associated with high ECa is assumed to facilitate development of anoxic microsites which led to more reducing conditions. Due to the generally reducing conditions and higher occurrence of saturated piezometers, transects under SC-1 were considered to have the most potential for intense nitrate reduction. In a tile drained setting, classifications based on average ECa and slope values may be utilized as parameters for a simple mapping tool for improved fine scale prediction of potential hotspots for nitrate reduction.

Geochemical controls on the distribution of radio-trace elements in groundwater resources of Shir-Kuh granitoid aquifer, central Iran

Abstract Granitic groundwaters are important resources in arid regions. However, they are not always pure due to having appreciable amounts of trace elements. The present study was conducted to investigate chemical compositions for finding controls on distribution of heavy metals and natural radioelements (U and Th) in groundwater resources of Shir-Kuh granitoid aquifer (SGA), central Iran. Thirty water samples were collected and analyzed for major and trace elements. The average values of electrical conductivity (EC) and pH are 624 μs/cm and 7.5, respectively. The dominant groundwater type is Ca-HCO3, as a result of the calcite dissolution and biotite weathering. Principal component analysis in support of mass balance studies recognizes dissolution of fracture-filling sediments and rock mineral weathering as the main factors enhancing major ions in SGA. These processes also release trace elements in decreasing order of Sr > Ba > Sn > W > Cu > U > Zn > Th. Weathering of biotite enclosing accessory minerals of monazite and zircon is introduced as the main source of radio-trace elements in SGA. Health concerns are currently related to U in drinking groundwater, as the maximum concentration (13.6 μg/L) approaches the Iranian drinking standard of 15 μg/L, in response to the oxidizing nature of the groundwater, calcite dissolution-related mobilization, and the degree of the water–rock interactions.

Study of Electronic, Magnetic, and Thermoelectric Properties of 24 Valence-Electron Fe2TiSn Heusler Compound Using Modified Becke-Johnson Scheme

The first-principle investigation of electronic and transport properties of 24 valence-electron Fe2TiSn Heusler compound have been carried out using modified Becke-Johnson scheme. The compound possesses Fm-3m structure configuration in the ground state. Spin-polarized electronic calculations reveal Fe2TiSn is a semiconductor in both the spin configurations with a total magnetic moment as 0μB, which is consistent with the Slater-Pauling rule. The thermoelectric properties were calculated by means of the semiclassical Boltzmann transport theory. The average values of electrical conductivity, thermal conductivity, and Seebeck coefficient at 300, 600, and 900 K temperatures versus chemical potential are reported and discussed in detail. Further, the results show the possibility to create n-type and p-type thermoelectrics within one type of Heusler compound. The large Seebeck coefficient advocates the compounds to be good for thermoelectric applications.

Deep earth electrical conductivity-depth profiles around African geomagnetic equator using solar quiet currents

Electrical conductivity structure of the Earth’s deep interior has been successfully mapped out down to approximately 1500 km around the geomagnetic dip equatorial regions of Africa using solar quiet-day ionospheric currents. Spherical harmonic analysis (SHA) was employed in separating the internal and external field contributions to the solar quiet variations. Transfer function was used for each of the external and internal pairs to compute the conductivity-depth profile for the region. Calculated average electrical conductivity values were evidently higher than obtained in other parts of the world farther away from the geomagnetic equator. Sq current vortex foci are observed very close to the geomagnetic equator. Depth of penetration was greatly enhanced. Stations on latitudes less than 1° from the geomagnetic equator show higher electrical conductivity when compared with that situated more than 4° away from it at various corresponding depths. Evidence of discontinuities in the earth layers were also noted at some depths. Highly conductive layers were delineated around 400 km depth and beyond 1200 km.

The Effects of Temperature and Milk Fat Content on the Electrical Conductivity of Kefir during the Incubation

In this study, the relationships between the electrical conductivity and temperature for different milk fat contents were investigated during the incubation of kefir. For kefir production, three milk samples at different fat contents (0.15, 1.7 and 3.0%) and two incubation temperatures (25 °C and 35 °C) were selected. The inoculum level was 2%. The kefir fermentation time was approximately 10 h and the pH of kefir samples were 4.4 in the last stage. The test results showed that electrical conductivity (EC) increased at both the temperatures. The average EC values of non fat milk kefir were in the range of 4.72 mS/cm – 6.4 mS/cm at 35 °C, and 4.72 mS/cm – 5.71 mS/cm at 25 °C. The average EC values of full fat milk kefir were in the range of 4.84 mS/cm – 6.41 mS/cm at 35 °C, and 4.84 mS/cm – 5.63 at 25 °C. The average EC values of low fat milk kefir were in the range of 4.54 mS/cm – 6.39 mS/cm at 35 °C, and 4.54mS/cm – 5.5 mS/cm at 25 °C. Electrical conductivity of samples showed little improvement at low incubation temperature and fat content. Statistically, there was a significant difference (p < 0.05) in EC among samples.

Pollution Status of Balu River due to Industrial Input at Dhaka, Bangladesh

Physical parameters of the water are the main properties indicating the status of water quality. Major physical parameters to evaluate water quality were Electrical Conductivity (EC), pH, Dissolve Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolve Solids (TDS) and Turbidity. This study reveals variations of water quality of Balu River at Dhaka, Bangladesh during rainy and winter seasons between February’ 2008 to June’ 2008. The samples were collected from ten different sports at two different depth of water (surface and 5m depth). In dry period, the highest average values of EC, Turbidity, DO, BOD and TDS were 715.1 μS/cm, 18.87 NTU, 1.04 mg/l, 8.06 mg/l and 87.3 mg/l respectively. While in rainy period, the highest average values of EC, Turbidity, DO, BOD and TDS were 118.6 μS/cm, 11.13 NTU, 2.77 mg/l, 6.56 mg/l and 69.81 mg/l respectively. The river was found unsuitable for drinking, domestic, irrigation and industrial purposes. Poor river water quality impacts the ecosystem and aesthetic features very negatively.

Thermoelectric properties of a single graphene sheet and its derivatives

The thermoelectric properties of pristine graphene and H2S adsorbed onto bridge, hollow and top sites of a graphene sheet are investigated using the semi-classical Boltzmann transport theory. The average values of electrical conductivity, thermal conductivity, Seebeck coefficient, figure of merit (ZT) and the average value of the power factor (Pav) are reported and discussed in detail. While pristine graphene is a zero band gap semiconductor, adsorption of H2S onto the bridge site opens up a direct energy gap of about 0.04 eV, adsorption of a H2S molecule onto the top site opens up a gap of 0.3 eV, and adsorption of H2S onto the hollow site makes it metallic. The investigation of ZT and power factor values suggests that a top-site configuration could be a potential candidate for thermoelectric applications in the range 300–600 K.

An ecological study of two shallow, equatorial lakes: Lake Mburo and Lake Kachera, Uganda

AbstractLake Mburo and Lake Kachera are shallow, eutrophic lakes in mid‐western Uganda. Lake Mburo recorded higher values of Secchi and eutrophic depths and lower extinction coefficient (k) values. The lakes showed a ‘red shift’ phenomenon in maximum light transmission. The average values of electrical conductivity in Lake Mburo and Lake Kachera were 136 and 244 μS cm−1, respectively. The pH values indicated high photosynthetic activity. Dissolved oxygen concentration averaged 6.9 and 7.8 mg l−1 in Lake Mburo and Lake Kachera, respectively. The lakes had high total nitrogen (TN) : total phosphorus (TP) ratios averaging 200 and 280 in Lake Mburo and Lake Kachera, respectively. The lakes are dominated by cyanobacterial blooms that reduce light penetration to less than 1 m. Lake Mburo had a lower algal biomass than Lake Kachera. Chlorophyll a concentrations correlated positively (r = 0.73, P &lt; 0.05) with the extinction coefficient in Lake Mburo but not in Lake Kachera. The correlations between chlorophyll a and TN and TP were also high. Both lakes recorded high primary productivity, Lake Mburo showing higher values. The study highlighted the need to investigate the organism–community interrelationships in the two water bodies.

Field Study of Salt Balance of a Land Application System

Wastewater land application is a cost-effective method to treat and dispose wastewater; however, it may cause soil salinization. Salt mass balance and the potential soil salinization caused by the wastewater land application were investigated in the crop root zone in a wastewater land application system at the City of Littlefield, TX, USA from October 7, 2005 to September 28, 2007 using a lysimeter system. This study showed that, after 2 years of wastewater land application, the ranges of soil salinity were still lower than the threshold (8,500 μS/cm) for Bermuda grass assuming a 10% yield reduction. The leached salt mass showed large spatial and temporal variation. The average values of electrical conductivity of the saturated paste extract of the soil samples increased from 1,433 μS/cm in June 2006 to 1,840 μS/cm in June 2007. The average values of the soil sodium adsorption ratio between June 2006 and June 2007 increased from 11 to 14 resulting in a potential risk of soil dispersion and decreasing the soil infiltration rate. Although the measured leaching fractions in nearly all sampling periods, except one, were higher than the leaching requirement, salt accumulations in the root zone were still found with only two exceptions. Since the time required for reaching equilibrium between cumulative salt mass input and cumulative salt mass output varies from 1 year to a few years, or even longer, the long-term investigation is recommended for the study of salt mass balance in the root zone of this wastewater land application system.

Properties of copper matrix reinforced with nano- and micro-sized Al 2O 3 particles

The mixture of electrolytic copper powder with 5 wt.% of commercial Al 2O 3 powder (average particle size: 15 and 0.75 μm, respectively) and the inert gas atomized prealloyed copper powder (average particle size: 30 μm) containing 2.5 wt.% aluminum were separately milled in air up to 20 h in the planetary ball mill. During milling aluminum in the prealloyed copper powders was oxidized in situ by internal oxidation with oxygen from the air forming very fine nano-sized Al 2O 3 particles. The internal oxidation of 2.5 wt.% aluminum generated 4.7 wt.% of Al 2O 3 in the copper matrix. Powders and compacts were characterized by light and scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction analysis. Microhardness and electrical conductivity were also included in measurements. The microhardness of Cu–2.5 wt.% Al compacts was 3.6 times higher than that of compacts processed from electrolytic copper powder. This increase in microhardness is a consequence of a fine dispersion of Al 2O 3 particles and refined grain structure. The average values of electrical conductivity of compacts processed from Cu–5 wt.% Al 2O 3 and Cu–2.5 wt.% Al powders previously milled for 20 h and were 88% and 70% IACS, respectively, which is a rather significant increase if compared with values of 60% and 23% IACS of compacts processed from as-received and non-milled powders. The microhardness of 20-h milled compacts decreases with the heat treatment at 800 °C. Due to the effect of nano-sized Al 2O 3 particles Cu–2.5 wt.% Al compacts show lower decrease in microhardness. The results are discussed in terms of the effect of Al 2O 3 particle size and fine grain structure on the reinforcing of the copper matrix.