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Horizontal Loop Electromagnetic (HLEM) and Induced Polarization (IP) methods have been carried out within Um Salim gold mine area. The study area reveals special importance, as it comprises rock units, which show some indication of the presence of various mineralization. The result of HLEM has shown significant and well-defined conductive zones are recorded along with the four used frequencies (110 Hz, 440 Hz, 1760 Hz, and 7040 Hz) at the station 2,782,900 and station 2,782,880 of two (HLEM) profiles (596,050 N & 596,240 N) respectively, that may reflect the sources of the conductive bodies are situated at shallow depths continued to considerable depths. The result of IP exhibits a strong anomalous zone centered at stations 140 and 240, with chargeability values ranging (37 to more than 120 mV/V) on chargeability model section, and corresponding to high resistivity on resistivity model section which may reflect considerable surface and subsurface disseminated mineralization. Through the integration between HLEM and IP a core drilling is recommended at station 140 on IP profile which coincides with station 2,782,850 on HLEM profile (596,240 N) to a depth of concerning 100m take a look at the thickness, depth, and grade of mineralization.

Converter transformers in HVDC stations are subject to both AC and DC stresses. With new oils entering the market it is important that these are characterized both for AC and DC. This paper focuses on DC characterization of one such oil, which is an isoparaffinic oil produced using a gas to liquid production process. The results are compared to mineral oil as reference. The isoparaffinic oil is shown to have a very high resistivity. In fact, the resistivity is so high that it is more resistive than impregnated pressboard with low moisture content. This is a dielectric risk which must be considered if the oil is to be used in converter transformers.

Parangtritis has a rock fall hazard area with a medium to high level of risk. In Parangtritis, there was a large scale paleo-rockslide that involved more than 800 million m3 of rock mass with an area of 1500 m x 2700 m. This is a significant factor in changing the landscape. This research uses 9 Audio-MagnetoTelluric (AMT) primary data points. Using the distance between points 750 m within a 2 km x 2 km study area. The location focused on the western side of the paleo-landslide area in Parangtritis Village. Processing AMT data using the help of MT-INV and RockWorks software. The result of one-dimensional inversion consists of 3 layers. Indicates a low resistivity value (0-10 Ωm) interpreted as beach deposition and sand dune, medium resistivity (50 - 160 Ωm) for Wonosari limestone and high resistivity ( 170 Ωm) for Nglanggran andesite breccias. The average thickness of the first layer is 44 m and the second layer reaches 175 m. Based on the resistivity structure of the AMT data, the interpretation of the boundary contact between the Wonosari limestone and the Nglanggran andesite breccia can act as a slip field in a depth of about 250 m This field is a passive fault field controlled by the Girijati fault in the east of the study area.

In this paper we demonstrate the imaging capabilities of a newly developed 3D Gauss-Newton inversion algorithm for marine controlled source electromagnetic (CSEM) data by inverting synthetic data generated from a known salt resistivity model. We show that the high resistivity contrast between salt and background sediments can be utilized to reconstruct reliable images of the salt structure without the use of any a-priori information which could bias the outcome. Further, we re-invert a CSEM data set acquired in 2012 in the Salina basin in the Gulf of Mexico, using the same 3D Gauss-Newton inversion algorithm. The resulting resistivity model is compared to the initial salt interpretation based on seismic data. The top salt boundary in the inverted resistivity model correlates well with the initial interpretation. However, the base salt geometry, which is often difficult to map with seismic data alone, is imaged very differently. The CSEM inversion result is robust and independent of other geophysical data and therefore very valuable in a salt imaging workflow to support seismic interpretation and velocity model building.

This article analyzes the performance of pinned photodiode (PPD) for Time-of-Flight(ToF) applications on high resistivity epitaxial wafers. Due to its wide depletion region, high epitaxial resistivity PPDs feature some key advantages in collecting photogenerated charges. This article compares the demodulation contrast of the same pixel design on epitaxial wafers with different resistivity at near-infrared wavelength to analyze their performance. By comparing the simulated profile of pixels with different epitaxial resistivity, the characteristics of the PPD pixel on high resistivity epitaxial wafer when collecting photogenerated charges are concluded. This article also discusses the effects of using high resistivity epitaxial wafer with various design parameters. It is found that the use of high resistivity epitaxial wafer can greatly improve crosstalk performance, allow pixels to work at higher modulation frequencies, and enable large-sized pixels to have good demodulation capabilities.

The research had been performed using Magnetotelluric to get a 2D model based on variations in resistivity of the subsurface rock. The purpose of this study was to determine the hydrocarbon formation zone. The research method to achieve the research objectives, among others, the first filtering performed on the data with a robust process. This process consists of Robust No Weight, Robust Rho Variance and Ordinary Cohenerency. The second step is done to change the format Selection XPR And Edi. A third inversion resistivity model for the review get a 2D cross section. Based on the findings of the eight data processing methods of measurement points obtained information Magnetotelluric rock formations. Formation hidrokrabon What are the areas is research a reservoir and caprock. The layer in 1600 m – 2700 m depth from the surface which resisvity 12 -33 m assumpted as clay cap. While the layer in 2700 m – 5000 m depth from the surface with high resistivity 41- 250 m is assumpted as oil sands (reservoir). The trap zone of this hidrocarbon formation categorized into structural trap which is the trap of anticline.

Eight time-domain electromagnetic profiles were carried out in Harrat Ithnayn, northwestern Saudi Arabia, to detect potential groundwater-bearing aquifers in the area. The collected data were processed and analyzed, with the results inferred or extrapolated between one-dimensional vertical soundings to obtain two-dimensional resistivity sections of the subsurface geological setting. We found that the resistivity values change laterally and vertically throughout the area. High resistivity values (greater than 100 Ohm-m) occupy most of the sections down to depths of approximately 100–150 m, whereas the low-resistivity regions of the section appear to be shallower than 100 m toward the west in the northern part of Harrat Ithnayn. The high-resistivity regions correspond to the Harrat basalts and are underlain by low resistivity (down to a few Ohm-m) in the saturated zones. There are also localized regions of low resistivity at depths of approximately 20–30 m, indicating shallow local groundwater aquifers. Aquifer thickness varies from approximately 50 to more than 100 m. In the southern part, the resistivity sections indicate that the main aquifer is at a depth of 150–200 m (possibly near 170 m) below the basalt. A saturated zone or shallow aquifer approximately 20–30 m thick also exists at a depth of approximately 15 m. In both the shallow and deep aquifers, the resistivity values indicate that there is good quality fresh water.

The results of studies of nominally undoped epitaxial p-GaSb layers grown by metal–organic vapor-phase epitaxy at a ratio TMSb/TEGa in the range from 1 to 50 are reported. At the ratio TMSb/TEGa = 50, GaSb epitaxial layers, whose resistivity is 400 Ω cm, are produced. It is shown that, for such layers, the crystal quality assessed by several methods remains comparable to the quality of n-GaSb substrates used for the growth of nominally undoped GaSb layers.

Soil sinking is a major engineering concern need to be addressed through proper planning and investigation. Usually Engineers depend on borehole data or soil tests for designing the solution for such problems. In view of cost, time and less destruction, geophysical methods are best to probe such engineering and environmental problems. Therefore, Electrical resistivity tomography (ERT) method used to investigate soil sinking in Satellite town Langerpura, Sub Himalayas Azad Jammu and Kashmir Muzaffarabad Pakistan. Two profiles acquired overlap the zone under study with electrode spacing 5m and average depth of 40-50m. Three different geological zones are identified on the base of resistivity data. Low resistivity zone having resistivity 3.0 – 15Ωm is water saturated friable sandstone. Intermediate resistivity zone with resistivity range 100-1000 Ωm consists of alternate layers of sand, clay and river deposits. High resistivity zone with resistivity range 1000-4000 Ωm show cavities in subsurface. The room size cavity detected which cause the soil sinking at surface. Muck filling or compaction grouting recommended as engineering solution for stabilization of sink soil.

Electrical Resistivity Imaging (ERI) is a tool used in near surface geophysical surveys by flowing an electric current through electrodes that were injected into the ground. The usage of electrical resistivity imaging (ERI) method dominated by geophysicist has increased tremendously in geotechnical engineering application owing to the efficiency and effectiveness of the method in term of time, cost and also data coverage. The survey performed with respect to the particular reference to ERI in determining the granite rock underneath the ground. There were seven (7) lines of ERI performed at the study area by using ABEM Terrameter LS 2 set of equipment based on Schlumberger protocol. Six (6) boreholes were also drilled to obtain engineering properties of rock at the study area. In order to develop the relationship between resistivity and engineering properties, a comparison between borehole field test result and the resistivity value were made. Results from the ERI indicated the presence of zones with high resistivity values identified as overburden soil, fractured granite and solid granite. The findings of this study also showed that the electrical resistivity imaging coupled with borehole drillings were applicable tools for the determination of the granite rock underneath the ground via subsurface profiles and such as depth of overburden soil and engineering properties of soil. In conclusion, ERI is a method that does not disturb the structure or the function of the soil which successfully became the best method in exploring the granite rock.

The B-P gas field locates on the middle section of Region B on the right bank of the Amu Darya, Turkmenistan. In geological structure, it belongs to central uplift belt of Sandykly of Zarzhu terrace, Amy Darya basin. The higher structure parts produce gas, the lower structure parts produce gas and water and some of the low position wells produce only water. The gas reservoir’s upper parts have high resistivity, low water saturation and a obvious gas reservoir character when the lower parts have low resistivity, high water saturation with a obvious character of water in reservoir which means the gas reservoir is controlled by geological structure mainly. Meanwhile, the whole gas reservoir can be divided into four individual gas-water system based on the gas-water interface and conversion pressure of each well which means this gas reservoir is also controlled by lithology.

Geophysical survey for cavity detection is one of the most common near surface application. The usage of resistivity methods are also very straightforward for the air filled underground voids, which should have theoretically very high resistivity in the ERT image, whereas the water filled cavities have low resistivity in Electrical Resistivity Tomography (ERT) image. Three different geoelectric arrays Wenner, Schlumberger and Dipole-dipole are applied for detecting cavities. The survey results suggest that ERT is a viable geophysical tool for the detection and monitoring of mining voids and other subsurface cavities. The resolution capacity of joint Wenner-Schlumberger, Dipole-dipole array for the detection of cavity is greater than that of the individual one. Using the ERT survey in Patherdih Thana Basti village (Jharia coal field), a number of air filled cavity or water filled mining voids are detected at around 25-30m of below the ground level at different profile distance of 630m profile length along the road that extending S-E to N-W direction.

The principle of equivalence is known to cause nonuniqueness in interpretations of direct current (DC) resistivity data. Low- or high-resistivity equivalences arise when a thin geologic layer with a low/high resistivity is embedded in a relative high-/low-resistivity background formation causing strong resistivity-thickness correlations. The equivalences often make it impossible to resolve embedded layers. We found that the equivalence problem could be significantly reduced by combining the DC data with full-decay time-domain induced polarization (IP) measurements. We applied a 1D Markov chain Monte Carlo algorithm to invert synthetic DC data of models with low- and high-resistivity equivalences. By applying this inversion method, it is possible to study the space of equivalent models that have an acceptable fit to the observed data, and to make a full sensitivity analysis of the model parameters. Then, we include a contrast in chargeability into the model, modeled in terms of spectral Cole-Cole IP parameters, and invert the DC and IP data in combination. The results show that the addition of IP data largely resolves the DC equivalences. Furthermore, we present a field example in which DC and IP data were measured on a sand formation with an embedded clay layer known from a borehole drilling. Inversion results show that the DC data alone do not resolve the clay layer due to equivalence problems, but by adding the IP data to the inversion, the layer is resolved.

The influence of resistivity for n-AlGaN is investigated by changing Si concentration, growth temperature and growth rate. It is found that the resistivity strongly depended on the growth conditions and it reaches to a small value of 5 × 10−3 Ω cm at the growth temperature of 1040 °C. In addition, it is found that there is a strong correlation between the resistivity and the PL emission intensity of group-III-vacancy–Si (VIII-Si) complexes. It indicates that defect compensation can play a key role in high resistivity of n-AlGaN films.

In this paper, we describe a setup for modeling hydrate-bearing rock samples and measuring their electrical resistivity at different pressures and temperatures using an AMNB cylindrical four-electrode probe. Methods for modeling hydrate-bearing rock samples and measuring their resistivity are considered. The setup was used in a series of experiments to measure the resistivity of sand samples containing water, ice or tetrahydrofuran (THF) hydrate. It is shown that when the rock pores contain hydrates and a partially unfrozen aqueous solution of NaCl and THF, the electrical resistivity is determined by the high resistivity of the solution and increases with the formation of hydrate. The presence of THF hydrate in the experimental samples increased their resistivity by 180–320 Ohm·m at a temperature of about 0 °C. After the formation of hydrate and freezing of residual water, the resistivity of the sample is stabilized at 70–80 Ohm·m at a temperature of -15 °C.

2D imaging technique was applied in (8) transects near a pit of contaminated water near contaminated well southeast of Karbala city, Iraq. Each transect was 30 m long with 1 m electrode spacing. Data acquisition was fulfilled by using Wenner electrode array. The resistivity of water-contaminated zone is found less than 3Ω.m and the top dry zone recorded relatively high resistivity (more than 170Ω.m). It is found that the greatest amount of seepage was found moving towards northeast direction coincided with groundwater movement direction, whereas there was no movement towards northwest and southeast directions and restricted on the closest areas to the pit location. The outcomes suggested that the 2D imaging technique is a successful and powerful tool in separating contaminated zone from clear one and in detecting underground seepage depth and moving direction.

The highly reproducible effect of a giant (10 000-fold) increase in the electrical conductivity of a film sample of a high-resistivity MoS2 semiconductor with a layered structure under continuous proton injection in dynamic equilibrium conditions is reported for the first time. The effect disappears when the process of proton injection is interrupted. The potential to control the composition and the properties of materials by doping them with charge carriers of different signs, masses, and energies (as a complement to traditional chemical doping) is noted.

Hydrochemical analysis of water samples from Yenagoa in the Niger Delta shows widespread occurrence of iron (Fe) in the groundwater. The Fe concentration is more than 0.3 mg/L at many places, and the distribution is heterogeneous both vertically and horizontally. In order to identify the cause of the high heterogeneity, we carried out an integrated study consisting of hydrogeochemical, electrical resistivity sounding and induced polarization (IP) chargeability measurements at eleven sites and 2-D electrical resistivity profiling (at 2 sites). Data processing using inversion techniques resulted in 4-layered resistivity and chargeability—depth models. The results show that clean sand and gravel exhibit high resistivity but low chargeability and normalized chargeability values, whereas clay and sandy clay exhibit relatively low resistivity but high chargeability and normalized chargeability values. In sites where the aquifer is overlain by a thick clay layer, Fe concentration is high (Fe > 0.3 mg/L) in the groundwater and redox potential values range between 118 and 133 mV. We interpret that the low-permeability clay layer creates a relatively atmosphere-isolated state in the underlying aquifer, which is responsible for the reductive ambient subsurface groundwater environment. In sites where the aquifer is capped by silt, Fe concentration is low (

Kerfless p-type wafers of varying resistivity are grown with Direct Wafer technology with precise control of dosing the Boron concentration in the melt. At very low Boron concentration, bulk resistivity values ≫100 Ω-cm are achieved and an effective lifetime above 1 ms is measured, corresponding to an estimated bulk lifetime around 2 ms. In contrast to ingot-based wafers, continuous growth using Direct Wafer technology produces a very tight resistivity distribution at any desired target resistivity, without variations caused by zone refining. In addition, the technology enables growth of 3D wafers, e.g. thin wafers with a thick frame that allows to maintain mechanical wafer strength. Thus, Direct Wafer product can be customized for a given solar cell architecture by growing each individual wafer at the optimum bulk resistivity and optimum thickness.

Ferrites could see extensive use in spintronics, microwave communication technology, and biomedical applications, because of their excellent magnetic properties and high resistivity. At the nanoscale, though, surface disorder significantly decreases the magnetization of these beach-ball structures. In this article, the magnetization of Fe${}_{3}$O${}_{4}$ hollow nanospheres is increased substantially by Zn doping, up to a maximum. The same doping also increases the resistivity of the hollow nanospheres, further enabling them for applications.

Based on the characteristics of mine goafs, the geo-electrical models are established. In order to study the response characteristics of goaf by transient electromagnetic method, we have performed three-dimensional numerical simulations in three cases, geo-electrical model of mine geology without goaf, geo-electrical model of mine geology with low resistivity goaf and geo-electrical model of mine geology with high resistivity goaf. Moreover, the physical experiments have also been performed for the above three cases. Furthermore, we compare numeral simulation results and physical experiment results. Finally, we obtain the conclusion that although the response of high resistivity goafs is weaker than that of low resistivity, its response characters still can indicate the existing of goaf. Hence, above work actually signifies that shallow high resistivity goafs can be detected in a reliable way by transient electromagnetic method. DOI: 10.5755/j01.eie.25.1.22733

Fe-3Si-3Al and Fe-4Si-4Cr (wt%) experimental alloys were processed to assess the electrical resistivity and workability effects of substituting Al and Cr for Si in high-Si electrical steel alloys. The experimental alloys were made by arc melting, and processed by hot rolling and cold rolling to produce strips. Samples were characterized by means of metallography, hardness, workability and resistivity. Results showed that the two alloys could be rolled down to 200 µm thickness (90% hot-rolled reduction and 80% cold rolled reduction) without crack formation in the strips. Hardness in the annealed condition and electrical resistivity were 228 HV/74 µΩ cm and 243 HV/85 µΩ cm, respectively, for the Fe-3Si-3Al and for Fe-4Si-4Cr alloys. The resistivity measured for Fe-4Si-4Cr was higher than the resistivity reported for the benchmark high-Si alloy, Fe-6.5Si. Both experimental alloys showed improvement on the workability compared to Fe-6.5Si since there was no edge cracking on the cold-rolled strips up to 80% reduction, and the hardness was approximately 35% lower.

The determination of mineralization boundaries during mineral exploration for undiscovered low-sulfidation epithermal Au–Ag deposits is a significant challenge because of the extensive survey areas required. Induced polarization (IP) imaging is an effective geophysical technique for the detection of sulfides or clay. Thus, this method is considered useful to determine the boundaries of subsurface mineralization and hydrothermal alteration associated with epithermal deposits. We used 2D and 3D IP imaging to define the silicification and mineralization boundaries of the Moisan deposit in the Seongsan mineralized district, which is geologically well-known. The boundaries of the silicification zone were defined by high resistivity values of 600 Ω-m, and those of the mineralization zone were defined by high global chargeability values of 3 mV V−1. The continuity of the high resistivity anomaly corresponded well to the silicification (quartz veins) exposed in outcrop. In addition, it is geologically reasonable that the chargeability anomaly, ≥3 mV V−1, associated with the mineralization/hydrothermal alteration zone was concentrated at near-surface depths, and extensively surrounding the resistivity anomaly, ≥600 Ω-m, associated with the silicification zone.

The electrical role of the highly resistive and transparent (HRT) i-ZnO layer in Cu(In, Ga)Se2(CIGS) solar cells is investigated. By tuning the resistivity of atomic layer deposited (ALD) i-ZnO through the use of post-growth O2-plasma treatments, it is shown that low i-ZnO carrier densities (i.e. high resistivities) actually restrict the performance of CIGS solar cells by reducing the extent of band-bending of the CdS/CIGS junction (the effect of series resistance is ruled out as the origin of any observed differences). This is the first evidence that i-ZnO has a negative electrical effect in CIGS solar cells (alongside the positive effect of shunt mitigation), and based on these results, attempts to maximise resistivity of the i-ZnO (typically sought-after for this HRT layer) are not recommended. Device efficiencies of 12.5% were obtained when using low resistivity as-grown ALD i-ZnO (resistivity, p=0.6 ohm cm, carrier density, n=3.5 . 10-18 cm-3, and work function, O=4.06 eV), but this decreased to 11.5% when using high resistivity, plasma-treated ALD i-ZnO (p=134 Ohm cm, n=0.2·10-18 cm-3, and O=4.21 eV). SCAPS modelling revealed the reason for the difference to be the effect that the i-ZnO work function (controlled by carrier density) has on the band-bending and built-in voltage, Vbi, of the main junction. Capacitance-voltage experiments confirmed that the Vbi is lower (V-bi~0.1 V) when using low carrier density, high resistivity i-ZnO. This general effect was also found when using RF-sputtered i-ZnO, whereby the inclusion of high resistivity i-ZnO similarly generated lower efficiencies (15.0%) than low resistivity i-ZnO (15.9%).

A research of induced polarization and very low frequency method was carried out at Sangon Village, Kulonprogo to identify mineralization zone. The result of these methods were able to be used to support each other. Mineralization zone is shown by high resistivity and high hargeability area of induced polarization method, and is also shown by high electric current density area of very low frequency method. Interpretation of resistivity and chargeability model shows that mineralization zone is mostly located at the depth below 10 m from surface. On the other hand, interpretation of electric current density models at depth 10 m and 20 m show that mineralization zone is not well distributed respect to alteration zone, which is the character of low sulfidation epithermal type, mostly at north-south direction.

In this paper, a novel core–shell structured FeSiAl@MnO/Al2O3 soft magnetic composites (SMCs) has been fabricated by the combination of ball milling with MnO2 and spark plasma sintering (SPS) process. The structure and phase evolution of MnO/Al2O3 insulation layer also were investigated. Meanwhile, the influences of various MnO2 content on magnetic properties of FeSiAl SMCs have been revealed. The results indicate that MnO/Al2O3 insulation layer with high resistivity (32.46 mΩ·cm) is conducive to the frequency stability of permeability. In particular, the total core loss of FeSiAl@MnO/Al2O3 SMCs is only 6.71 W/kg, which is 94.1% lower than that of original FeSiAl (113.6 W/kg) at 50 kHz. It implies that the novel core–shell structure is a powerful method to increase resistivity and reduce total core loss of SMCs, which can significantly improve energy utilization.

In this paper we present the result of a magnetotelluric (MT) investigation carried out across the High Agri Valley (HAV), southern Italy. Several MT soundings were carried out in order to obtain a ~15 km long 2-D resistivity model with an investigation depth of ~10 km. The main aim was to provide valuable data on the geological and structural setting of the HAV. The MT model was compared with pre-existing geological, geophysical and seismic data. The MT model can be schematized as a superposition of three stack lateral varying layers with different thickness and resistivity values: a surficial low–medium resistivity layer associated with the Quaternary deposits and to the allochthonous units; and a deeper high resistivity layer related to the Apulia Platform, separated by a thin layer connected to the mélange zone and to the Pliocene terrigenous marine deposits. Sharp lateral resistivity variations are interpreted as faults that, on the basis of accurate focal mechanism computations, display normal-faulting kinematics.

Inflated values of true resistivity Rt measured by Dual Laterolog probe are still the problem for log analysts to determine proper water saturation value. Most often the erroneously high deep resistivity reading, known as the Groningen effect, appears in the series of the evaporative deposits.These anomalous high resistivity records from Dual-Laterolog were a serious problem in time where methods to eliminate this phenomenon were not widely available.The article describes the case study of the Polish solutions of the Groningen effect problem in the last few years provided by Geofizyka Torun SA as the well logging service company in Poland.

The SuperConducting Fault Current Limiter (SCFCL) appears as one of the most promising SC applications for the electrical grids. Despite its advantages and many successful field experiences the market of SCFCL has difficulties to take off even if the first orders for permanent operation in grids are taken. The analytical design of resistive SCFCL will be discussed with the objective to reduce the quantity of SC conductor (length and section) to be more cost-effective. For that the SC conductor must have a high resistivity in normal state. It can be achieved by using high resistivity alloy for shunt, such as Hastelloy®. One of the most severe constraint is that the SCFCL should operate safely for any faults, especially those with low prospective short-circuit currents. This constraint requires to properly design the thickness of the SC tape in order to limit the hot spot temperature. An operation at 65 K appears as very interesting since it decreases the SC cost at least by a factor 2 with a simple LN2 cryogenics. Taking into account the cost reduction in a near future, the SC conductor cost could be rather low, half a dollar per kV A.

Exploitation of CdZnTe crystals for X-ray imaging detectors is limited by the incorporation of tellurium inclusions during growth. Over the years, several post-growth thermal treatments have been proposed for the removal of tellurium inclusions, often compromising the high electrical resistivity of the material. Moreover, main attention is usually paid to large inclusions, whose direct connection with the deterioration of detector properties has been demonstrated, while the effect of thermal annealing on small inclusions is usually neglected. In this article, the effect of different thermal annealing process on the concentration of inclusions down to 1 μm size is studied. A two-step process in tellurium vapors has been shown to be effective to anneal large tellurium inclusions and to preserve the high resistivity of the samples as well.

In studying and development of unconventional reservoirs, it is important to know vertical component of resistivity. This information can be obtained by HRLA or Rt-Scanner type devices, but due to low oil prices, using of them in Russia is becoming economically inexpedient. This leads to the necessity to develop a quantitative interpretation of the data of traditional Russian electrologging methods, which can provide information of the structure and properties of deposits with minimal cost. In vertical wells, in high-resistivity deposits similar to the Bazhenov formation, gradient sondes are sensitive to anisotropy, which was shown by the results of modeling and interpretation of signals on a one-dimensional cylindrical-layered model (Sukhorukova et al. 2013). A set of gradient sondes with different lengths is included in the equipment of the lateral logging sounding (BKZor also Russian lateral logging) method and is often used in Russia in the vertical wells survey. However, the application of the method is difficult if the thickness of the beds is small. In this paper, I propose a technique for processing BKZ data measured in complicated geological medium with small thicknesses of interlayers. To increase the accuracy of determining the parameters of an anisotropic medium, a two-dimensional geoelectric model and finite-element algorithms for solving direct problems are used. The geological object of study is a major source of unconventional oil in Russia – the Bazhenov formation, but the proposed technique is applicable to other objects. Based on the results of data processing for 18 wells from the Fedorovskoe and Russkinskoye fields, the features of resistivity anisotropy coefficient distribution by depth at intervals of the Bazhenov formation have been revealed.

This paper presents the design of 110kV substation grounding grid with high resistivity soil. A horizontal two layer soil model is built by means of the MALT program of the Software (CDEGS). The purpose of this paper is to minimize the touch and step voltages when the resistivity soil is high, in urban substation during a direct lightning stroke. The touch and step voltages in surface of the ground was calculated based on its soil resistivity in top and bottom layers. The calculated results are compared with the standard values that formulated in IEEE Guide for Safety in AC Substation Grounding.

The spin-Hall effect (SHE) is found to be strong in heavy transition metals, such as Ta and W, in their amorphous and/or high resistivity form. In this paper, we show that by employing a Cu-Ta binary alloy as a buffer layer in an amorphous $\mathrm{C}{\mathrm{u}}_{100\ensuremath{-}x}\mathrm{T}{\mathrm{a}}_{x}$-based magnetic heterostructure with perpendicular magnetic anisotropy, the SHE-induced dampinglike spin-orbit torque (DL-SOT) efficiency $|{\ensuremath{\xi}}_{\mathrm{DL}}|$ can be tuned linearly by adjusting the buffer layer resistivity. Current-induced SOT switching can also be achieved in these $\mathrm{C}{\mathrm{u}}_{100\ensuremath{-}x}\mathrm{T}{\mathrm{a}}_{x}$-based magnetic heterostructures, and we find the switching behavior better explained by a SOT-assisted domain-wall propagation picture. Through systematic studies on $\mathrm{C}{\mathrm{u}}_{100\ensuremath{-}x}\mathrm{T}{\mathrm{a}}_{x}$-based samples with various compositions, we determine the lower bound of spin-Hall conductivity $|{\ensuremath{\sigma}}_{\mathrm{SH}}|\ensuremath{\approx}2.02\ifmmode\times\else\texttimes\fi{}{10}^{4}[\ensuremath{\hbar}/2e]{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}\phantom{\rule{0.28em}{0ex}}{\mathrm{m}}^{\ensuremath{-}1}$ in the Ta-rich regime. Based on the idea of resistivity tuning, we further demonstrate that $|{\ensuremath{\xi}}_{\mathrm{DL}}|$ can be enhanced from 0.087 for pure Ta to 0.152 by employing a resistive TaN buffer layer.

Landslide is defined as a form of ground movement in which land mass suddenly fails downward on a slope as aresult of gravitational pull. One of the mitigative approaches into investigating landslide is to identify a potential slip zone usingresistivity method. In this study, the array chosen to acquire the resistivity data was Wenner array as it provides a robust resolution in mapping lateral resistivity variations. This method will generate a contour map portraying thedistribution of resistivity values of the subsurface. Beforehand, a 2-dimensional forward modeling was conducted to acquire anexpected ideal result of possible potential slip zone. Landslides itself are affiliated with a low resistivity zone that is locatedbetween two high resistivity zones. This study is conducted in a ground slump in Jalan Citra Green, Northern Bandung which is comprised of mostly unconsolidated soil. By applying a least-square inversion to the resistivity data obtained, resistivity values of 10-200 Ωm is attained. Based on the inversion result, a low resistivity zone of 10-20 Ωm is identified spanning from the surface to approximately 10 meters deep. In conclusion, furtherinvestigations are needed to determine whether the low resistivity zone is associated with potential slip zone as our datais limited to a single lineLandslide is defined as a form of ground movement in which land mass suddenly fails downward on a slope as aresult of gravitational pull. One of the mitigative approaches into investigating landslide is to identify a potential slip zone usingresistivity method. In this study, the array chosen to acquire the resistivity data was Wenner array as it provides a robust resolution in mapping lateral resistivity variations. This method will generate a contour map portraying thedistribution of resistivity values of the subsurface. Beforehand, a 2-dimensional forward modeling was conducted to acquire anexpected ideal result of possible potential slip zone. Landslides itself are affiliated with a low resistivity zone that is locatedbetween two high resistivity zones. This study is conducted in a ground slump in Jalan Citra Green, Northern Bandung which is comprised of mostly unconsolidated soil. By applying a least-square inversion to the resistivity data obtained, resistivity values of 10-200 Ωm is attained. Based...

We have conducted a comparative study to determine the most efficient and reliable way to calculate the depth of investigation (DOI) index to assess the quality of electrical resistivity tomography models. We compared the results of using resistivity and logarithm of resistivity after testing them on four synthetic models by direct modeling and a field case, in which the resistivity model was validated by auger drillings. We tested the two most commonly used acquisition arrays, dipole-dipole, and Wenner-Schlumberger. The index calculated with the logarithm of resistivity clearly appears to be more satisfactory than the resistivity-based index. The method based on resistivity systematically overestimates risk (high DOI) in areas of high resistivity, and it underestimates risk in conductive zones. As a result, we strongly recommend the use of the logarithm of inverted resistivity to calculate the DOI index.

Geoelectric strike and resistivity structure of the crust have been estimated from 37 magnetotelluric (MT) data sites along a profile from Roorkee to Gangotri in Uttarakhand Himalaya. Impedance decomposition schemes based on Bahr’s, Groom Bailey and Phase tensor were implemented in a MATLAB code for the average strike estimation. Geoelectric strike direction varies with period as well as in different litho-tectonic units along the profile. In the period band from 1 to 100 s average geoelectric strike in the southern end of the profile (Indo-Gangetic Plains) is N79°W, which is slightly rotated to the north in the Lesser Himalayan region and becomes N68°W whereas it is N81°W in the Higher Himalayan region. However, average strike is stabilized to N77°W for the entire profile in the long period band (100–1000 s). Geoelectrical structure of the crust has been obtained along the profile by 2D inversion of MT data. Major features of 2D resistivity model are: (i) southern part of the model is a low resistivity ( 1000 Om) layer below the IGP sediments is the basement rock, representing the resistivity of the top of the subducting Indian Plate; (iii) the Main Boundary Thrust (MBT) and the Main Central Thrust (MCT) zones can be seen in the electrical image. However, the Himalayan Frontal Thrust (HFT) could not be resolved and (iv) a low resistivity (

Silver powders were synthesized by reducing a silver organometallic compound, silver 2-ethylhexanoate, with di-n-octylamine. The effects of preparation conditions on the characteristics of the powders were investigated. Silver powders prepared from silver 2-ethylhexanoate and di-n-octylamine in the ratio 2:1 (MA21) at 150°C for 3 h had the best characteristics (average particle size 277 nm, narrow particle-size distribution, high tap density of 4.0 g/cm3), and were also obtained in high yield (98%). Use of an excessive amount of di-n-octylamine resulted in intense thermolysis and a low yield of silver powders of irregular morphology with a wide particle-size distribution. As the proportion of silver 2-ethylhexanoate was increased, the silver powders obtained had a bimodal particle-size distribution and a relatively low tap density. Silver films seemed to have high resistivity when the temperature used for synthesis of the silver powders was too low or reaction time was insufficient. The electrical resistivities of silver films prepared from MA21 powders and sintered at 300°C and 500°C for 30 min were 3.8 × 10−6 Ω cm and 2.3 × 10−6 Ω cm, respectively, close to that of bulk silver.

The karst cavities can cause great harm to the construction or running of expressway. During the construction of expressway, the detection of these unfavorable geological objects is usually by use of high density resistivity method, and the physical background of the method is the combination of high resistivity of bedrock and low resistivity of karst cavities. In the study area, the Kaihua segment of Hangzhou-Xinanjiang-Jingdezhen Expressway, the widely distributed rich carbonaceous bedrock shows low resistivity, and the conventional interpretation idea of high density resistivity method is not applicable. The research results of this paper suggest that the U shape of relative high resistivity can be an indicative for detection of unfavorable geological objects such as karst cavities. 6 out of 11 boreholes drilled for purpose of calibration revealed karst cavities, and the karst ratio is from 1.2% to 10.3%, indicating the new interpretation method is feasible and reliable.

Availability of water for daily activities has constituted serious challenge at the College of Engineering, Afe Babalola University, Ado-Ekiti. Hence, geophysical study of the College was conducted to investigate its groundwater potential with a view to proffer solution to water availability in the study area. Profiling and Vertical electrical sounding methods were employed using Dipole - Dipole and Schlumberger configuration respectively. Eight points were sounded along three traverses and one profile was occupied. Five different subsurface lithologic units were established namely; lateritic topsoil, sandy-clay, weathered basement, fractured basement and, fresh basement. The curve types range between simple K, H to complex HA, HK and KH. The topsoil, sandy-clay and weathered basement materials are characterised with relatively low resistivity values while the fresh basement materials are characterized with high resistivity values. The average resistivity and thickness values for the topsoil are 178Ωm and 1.0m respectively. Sandy-clay was encountered in six locations with average resistivity and thickness values of 23Ωm and 7.0m respectively. Weathered basement was encountered in six locations with average resistivity and thickness values of 231Ωm and 8.0m respectively. Fractured basement was encountered in four locations with average resistivity and depth to the top of fracture values of 294Ωm and 18.0m respectively. Basement is relatively shallow in the study area, it was encountered in three locations and the average resistivity and depth values to the top of basement are 1000Ωm, and 11.0m respectively. Overburden thickness was established in six locations with an average value of 11.0m. The combination of overburden materials with the fractured basement constitutes aquiferous units within the study area. The groundwater potential of the area is rated as medium with VES 2 and 5 more promising.

In order to improve the identification and evaluation accuracy of low resistivity oil layer and complex pore structure oil layer, and to avoid the interpretation error caused by the traditional evaluation mode of “high resistivity is oil layer and low resistivity is water layer”, the method of calculating water saturation by radial resistivity ratio was studied. The results show that the radial resistivity ratio can be used to calculate the reservoir water saturation for completely invaded formation, which can be deduced according to archie formula. The new formula does not evaluate oil and water layers based on high or low of resistivity, but can be used to evaluate low resistivity oil and high resistivity water layers. After testing core experimental data, The new formula can effectively calculate the water saturation and meet the requirement of using. After practical application of data, The average absolute error of the calculated water saturation is 3.55%, which conforms to the industry standard. This method is helpful to improve the coincidence rate of logging interpretation, and is worth popularizing.

Electrical resistivity imaging survey was carried out at the proposed site for Kauridan Estate at Ibagwa - Nike, Southeastern Nigerian, in order to investigate the suitability of the subsurface geological structures for the housing estate. The multielectrode ABEM Lung resistivity meter system, employing the Wenner array, was used to acquire 2D resistivity data sets along six parallel profiles in the survey area. The acquired data was processed and interpreted using Res2DINV software to produce the 2D inverse resistivity models. The subsurface images showed that the near surface materials, up to a depth of about 7m from the surface, have moderately high resistivity range of 728 - 1100Ωm, and were inferred to be coarse sand and gravel. These materials were underlain by other materials of a lower resistivity range of 164-358Ωm at a depth of 26.2m, which vary from shaley sand - shale. The images did not suggest the presence of clay formations or any other building constraints such as fractures, faults or voids.

Post-growth annealing is a potentially promising method of improving the properties of CZT for fabricating room-temperature X-ray and gamma-ray detectors. In this paper, we summarize some of our recent research on annealing detector-grade CZT crystals. Our results show that annealing in a Cd vapor effectively removes Te inclusions from CZT. The migration of Te inclusions was also observed for annealing in a temperature-gradient field. We recorded a loss of resistivity of the detector-grade CZT after annealing in a Cd vapor. The underlying mechanism of this loss was discussed, and solutions including two-step annealing (Cd annealing followed by Te annealing) and one-step annealing with Cd and Zn pressure control were proposed to maintain high resistivity.

This experiment represents the effect of impressed current cathodic protection with a variable resistor on concrete specimens. The effect of cathodic protection (CP) system on concrete structures can be changed at different condition. Especially, in marine concrete structures, it is difficult in applying impressed current CP by means of one rectifier in both high resistivity area (dry area) and low resistivity one (wet area). Thus, in this study, the variable resistor was utilized to fulfill similar CP effect on both high resistivity zone and low resistivity one in order to manage the problem. Specimens were concrete slab type with a base of 400mm × 400mm and a height of 70mm. Test factors were CP potential, CP current, and 4-hour depolarization potential. Test results showed that the variable resistor could have positive influences on an improvement in CP effects. In addition, environmental conditions had to be considered to reach enough CP potential and current in this system.

During 2011, high-resolution gravity and Direct Current (DC) Wenner-Schlumberger resistivity geophysical techniques were made over an area of 80×70 m at the location of a proposed educational building at Jarash City, north Jordan. The objectives of the study were (i) to evaluate the resolution of these geophysical techniques in field work in detecting and locating anomalies caused by subsurface structures and (ii) to provide additional rock stratigraphy information at the site. High-resolution gravity data were collected on 5 m grid station along survey lines spaced 5 m apart. Resistivity measurements were carried out utilizing the Wenner-Schlumberger array configuration with 2-m electrode spacing along thirteen profile lines. Results of the survey demonstrated a strong correlation between the two geophysical techniques and subsurface geology. The interpretations obtained from gravity of the field data provided useful information in detecting near-surface channels. The DC-resistivity surveys allowed the determination of the specific resistivity down to a depth of about 6.5 m. The results indicate zones of chalk, marl and chalky marl with limestone intercalation with low resistivity values. Moderate high resistivity values were detected and were attributed to the presence of marly limestone sedimentary rocks.

The CdxZn1-xS (x=00, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by using Chemical Bath Deposition (CBD) Technique. The prepared CdxZn1-xS thin films were characterized by X-ray diffractometer (XRD) and Scanning Electron Microscopy (SEM). The structural and morphological properties have been investigated. XRD pattern exhibits the hexagonal crystal structure of CdxZn1-xS. The dark electrical resistivity measurement was carried out in the temperature range 298 to 383 K by using two point probe method. The dark resistivity measurement shows that the prepared CdxZn1-xS thin films have high resistivity. The dark resistivity at room temperature was found to be of the order of ≥10 Ω cm for pure CdS and ≥10 Ω cm for CdxZn1-xS thin films. The dark resistivity was observed increased with Zn content.

The energy efficiency of the spin Hall effects (SHE) can be enhanced if the electrical conductivity is decreased without sacrificing the spin Hall conductivity. The resistivity of Pt films can be increased to 150-300 {\mu}{\Omega}*cm by mesoscopic lateral confinement, thereby decreasing the conductivity. The SHE and inverse spin Hall effects (ISHE) in these mesoscopic Pt films are explored at 10 K by using the nonlocal spin injection/detection method. All relevant physical quantities are determined in-situ on the same substrate, and a quantitative approach is developed to characterize all processes effectively. Extensive measurements with various Pt thickness values reveal an upper limit for the Pt spin diffusion length: {\lambda}_pt

WOS: 000390014100018, The Nevsehir Castle region located in the middle of Cappadocia with approximately cone shape is investigated for the existence of an underground city using the geophysical method of electrical resistivity tomography. Underground cities are commonly known to exist in Cappadocia. The current study has obtained important clues that there may be another one under the Nevsehir Castle region. Several 2.5-D resistivity profiles totaling approximately 4 km in length surrounding the Nevsehir Castle are measured to determine the distribution of electrical resistivities under the study area. Several high resistivity anomalies with a depth range 8-20 m are discovered to associate with a systematic void structure beneath the Nevsehir Castle. Because of the high-resolution resistivity measurement system currently employed, we were able to isolate the void anomalies from the embedding structure. Using 3-D visualization techniques, we show the extension of the void structure under the measured profiles.

The effect of addition of Cu and Fe on the electrical properties of Ni–Mn–Co–O based NTC thermistor compositions is studied. Compositions with very low resistivity were prepared by co-doping of very small amounts of Cu along with Co in NiMn 2 O 4 , without affecting the sensitivity very much. Compositions with high resistivity and good sensitivity were achieved by co-doping Fe with Co in NiMn 2 O 4 . The effect of sintering temperature on electrical properties was investigated and it was found that the resistivity and material constant increase with sintering temperature. The reliability characteristics of the compositions were studied by the accelerated thermal aging method. All the compositions exhibited very good reliability.