Low Resistivity Values Research Articles

Multi-functional phase for precision sampling resistors for HVDC voltage transformer and efficient microwave absorption

Precision resistor performance has a direct impact on the detection accuracy of DC voltage transformers since it is a crucial component for signal sampling in high-voltage DC (HVDC) voltage transformers. The accuracy of the resistance is directly related to the performance of the slurry, which is sintered to produce the resistance. In this article, two different kinds of conductive fillers carbon-based and metal-based were created using the hydrothermal technique and high-temperature carbonization, and the matching resistance slurry and thick film resistors were made by compounding glass powder and organic carriers. The findings demonstrate the resistance slurry prepared using copper nanopowder as a conductive filler can achieve lower square resistance values and can be adjusted within the range of 124 Ω/□ -1503 Ω/□ by changing the solid content, and the square resistance is less affected by temperature. It can be used as a precision resistor for preparing high-voltage DC voltage transformers. Furthermore, the prepared functional phase materials also exhibit satisfying microwave absorption performance. Typically, the copper nanopowder exhibits the RLmin of -23.77dB and the EABmax of 4.64GHz at 1.8mm. This work provides a reference for the application of functional phases in electronic slurry and microwave absorption fields.

Effect of silver doping on electrical characteristics of aluminum/HfO2/p-silicon metal-oxide-semiconductor devices

In this study, undoped and silver (Ag) doped hafnium oxide (HfO2) thin films were prepared by sol-gel dipping method and their effect as an interface material in a p-Si-based metal-oxide-semiconductor device was investigated for the first time. The structural effects of Ag doping were investigated using x-ray diffraction patterns. Al/HfO2:Ag/p-Si devices were fabricated using these films, and their electrical properties were characterized by measuring current-voltage (I–V) curves at room temperature. The ideality factor values of the devices decreased from 4.09 to 2.20 as the Ag doping ratio increased. Simultaneously, the barrier height values increased from 0.60 eV to 0.81 eV. The calculated series resistance values, determined by two different methods, demonstrated that the lowest resistance values were obtained at a 1% Ag doping ratio. Furthermore, the interface state densities were found to vary with the doping ratio. The improvement in electrical parameters resulting from Ag doping can be attributed to the reduction in molar volume due to structural phase transformation. The decrease in the ideality factor suggests enhanced carrier transport efficiency, while the increase in barrier height indicates improved energy band alignment at the metal/semiconductor interface.

Novel phenotype characterization utilizing electrical impedance myography signatures in murine spinal cord injury neurogenic bladder models

Neurogenic bladder (NB) affects people of all ages. Electric impedance myography (EIM) assesses localized muscle abnormalities. Here, we sought to investigate whether unique detrusor EIM signatures are present in NB due to spinal cord injury (SCI). Twenty-eight, 8–10 weeks old, C57BL/6J female mice were studied. Twenty underwent spinal cord transection; 8 served as controls. Cohorts were euthanized at 4 and 6 weeks after spinal cord transection. Each bladder was measured in-situ with EIM with applied frequencies of 1 kHz to 10 MHz, and then processed for molecular and histologic study. SCI mice had greater bladder-to-body weight ratio (p < 0.0001), greater collagen deposition (p = 0.009), and greater smooth-muscle-myosin-heavy-chain isoform A/B ratio (p < 0.0001). Compared with the control group, the SCI group was associated with lower phase, reactance, and resistance values (p < 0.01). Significant correlations (p < 0.001) between bladder-to-body weight ratios and EIM measurements were observed across the entire frequency spectrum. A severely hypertrophied phenotype was characterized by even greater bladder-to-body weight ratios and more depressed EIM values. Our study demonstrated distinct EIM alterations in the detrusor muscle of mice with NB due to SCI. With further refinement, EIM may offer a potential point-of-care tool for the assessment of NB and its response to treatment.

San Felipe Geothermal Prospect: A Previously Unrecognized Hydrothermal System on the Northeastern Coast of the Baja California Peninsula, México

Geophysical surveys discovered low resistivity values that, in combination with geochemical and structural data, indicate the presence of a previously unrecognized geothermal system with a possible maximum size potential similar to that of the presently installed capacity of the Cerro Prieto geothermal field. The only evidence of a hydrothermal system in the San Felipe Valley are warm groundwater wells and four intertidal hot springs. Exploration at San Felipe was part of a research project that included geological, geochemical and geophysical studies, which indicated the presence of low resistivity anomalies and high temperature at depth; the geological survey provided evidence of active fault systems that may act as channels for convective heat transport. Estimation of the energy potential of the San Felipe prospect using the heat in place method yielded a 50% probability of more than 300 MW that would add to the 570 MW of the Cerro Prieto geothermal field and can supply almost 40% of the state of Baja California electricity demand. The Baja California Peninsula is not connected with the national grid and has one of the highest electricity prices in Mexico, which should be an incentive to develop this clean energy source. The results of this work support the recommendation to pursue further advanced exploration of this prospect.

Unleashing the Potential of Binder-Free Hydrothermally Synthesized Marigold-Like ZnCo2O4 for Supercapacitors

An enormous interest has been generated in hybrid structured capacitive materials for supercapacitor. However, the sensible design with modified electro-mechanism and high energy density is still a demanding for supercapacitors. In this report, we developed a binder-free marigold ZnCo2O4 architectures on conducting Ni foam substrate from a simple one pot hydrothermal assisted thermal annealing process and used as an electrode for supercapacitor application. The electrode demonstrates a high specific capacitance of 1167 F g−1 (227 mAh g−1) at 1 mA cm−2 in 1 M KOH electrolyte. In addition, hybrid supercapacitor device was also fabricated by assembling as prepared marigold flowers-like ZnCo2O4 as positive electrode and activated carbon (AC) as the negative electrode, providing superior specific capacitance (166.7 F g−1 or 94.4 mAh g−1 at 1 mA cm−2) and long cycling stability (81.38 % after 10,000 cycles at 30 mA cm−2), the maximum energy and power density of 306 Wh kg−1 and 10,800 W kg−1 respectively, also a low resistance (0.9 Ω) value. Our work justify that the ZnCo2O4 marigold flowers-like electrode will be suitable for both criteria like high energy and power density appliances such as electric vehicles, portable electronics, and power storage systems.

Tunable bandgap and Si-doping in N-polar AlGaN on C-face 4H-SiC via molecular beam epitaxy

N-polar AlGaN is an emerging wide-bandgap semiconductor for next-generation high electron mobility transistors and ultraviolet light emitting diodes and lasers. Here, we demonstrate the growth and characterization of high-quality N-polar AlGaN films on C-face 4H-silicon carbide (SiC) substrates by molecular beam epitaxy. On optimization of the growth conditions, N-polar AlGaN films exhibit a crack free, atomically smooth surface (rms roughness ∼ 0.9 nm), and high crystal quality with low density of defects and dislocations. The N-polar crystallographic orientation of the epitaxially grown AlGaN film is unambiguously confirmed by wet chemical etching. We demonstrate precise compositional tunability of the N-polar AlGaN films over a wide range of Al content and a high internal quantum efficiency ∼74% for the 65% Al content AlGaN film at room temperature. Furthermore, controllable silicon (Si) doping in high Al content (65%) N-polar AlGaN films has been demonstrated with the highest mobility value ∼65 cm2/V-s observed corresponding to an electron concentration of 1.1 × 1017 cm−3, whereas a relatively high mobility value of 18 cm2/V-s is sustained for an electron concentration of 3.2 × 1019 cm−3, with an exceptionally low resistivity value of 0.009 Ω·cm. The polarity-controlled epitaxy of AlGaN on SiC presents a viable approach for achieving high-quality N-polar III-nitride semiconductors that can be harnessed for a wide range of emerging electronic and optoelectronic device applications.

Nickel sulfide nanowire-filled carbon nanotubes as electrocatalysts for efficient hydrogen evolution reaction

Developing a cost-effective, efficient, and eco-friendly electrocatalyst made from non-noble materials for the hydrogen evolution reaction (HER) is challenging. This research paper presents an application of the nickel sulfide (Ni3S2) nanowires-filled multiwalled carbon nanotubes (CNTs) synthesized on carbon cloth (CC) (Ni3S2@CNTs/CC) as an efficient HER electrocatalyst. The performance of Ni3S2@CNTs/CC as a working electrode was examined for its hydrogen evolution ability. In a 1.0 M KOH solution, Ni3S2@CNTs/CC requires cathodic overpotentials of 381 mV and 549 mV to generate current densities of 10 mA/cm2 and 100 mA/cm2, respectively. Electrochemical impedance measurements showed a low charge transfer resistance value of 3.3 Ω for Ni3S2@CNTs/CC.The evaluation of the electrochemically active surface area revealed that Ni3S2@CNTs/CC has more electrochemical active sites and a higher roughness factor than pristine CC. Most importantly, the current density of Ni3S2@CNTs/CC did not significantly degrade after 3000 CV cycles and 12 h of constant HER. These findings suggest that Ni3S2@CNTs/CC is a cost-effective, highly functional, and stable electrode material for HER in a strongly alkaline medium.

Bias Voltage Dependency of Structural and Bipolar Plate-Related Properties of Cathodic Arc-Deposited Carbon-Based Coatings.

Carbon-based coatings composed of a chromium interlayer and a carbon top layer were deposited on stainless steel substrates via cathodic arc evaporation. During the carbon deposition, the bias voltage was varied between 900 and 1 V to investigate the influence on the structural, electrical, and electrochemical properties. Raman spectroscopy indicated a dependency of the intensity ratio and G peak position on the bias voltage, which can be attributed to an alteration of the structure. Transmission electron microscopy (TEM) cross-section investigations revealed a graphite-like structure for most carbon top layers but with an increasing amount of disordered fractions, eventually resulting in an amorphous structure at 1 V. To further examine the structure, electron energy loss spectroscopy (EELS) was used. In the high-loss region, distinct π* and σ* peaks could be observed, which agree well with the TEM results. Additionally, analysis of the low-loss region showed that the 1 V carbon top layer exhibits a shifted σ plasmon peak at 20 eV corresponding to an amorphous structure. The carbon-based coatings are highly conductive with low interfacial contact resistance values between 4 and 1.5 mΩ cm2 at 150 N cm-2. From a bias voltage of 200 V, the resistance increases. To evaluate the corrosion resistance, we conducted potentiodynamic polarization tests. At first, with decreasing bias voltage, the corrosion resistance increases and then decreases for both the 100 and 1 V samples. Considering the low thickness, the coating with a carbon top layer deposited at 600 V had the best corrosion resistance. In combination with the excellent contact resistance, the 600 V sample is a highly suitable coating for metallic bipolar plates.

Impact of kaolinite and iron oxide cements on resistivity and quality of low resistivity pay sandstones

Low resistivity pay (LRP) zones have been identified within many siliciclastic reservoirs around the world, and have gained significant attention due to their ability to hold substantial hydrocarbon volumes. Previous studies have focused on investigating the role of highly conductive minerals, microporosity, bound water, and bed thickness in reducing resistivity within LRP zones. However, the impact of kaolinite and iron oxides in influencing the resistivity of LRP zones remains poorly understood. To address this, we examined outcrops cemented by pore-filling kaolinite and iron oxides, which serve as analogues to subsurface reservoirs. This study combined field description with laboratory analyses, including petrography, mineralogy, porosity, permeability, resistivity, and nuclear magnetic resonance to investigate the occurrence of kaolinite and iron oxide cements and their impact on resistivity and reservoir quality. The study observed various iron-bearing structures including concretions, fracture infills, layers, ferricrete, and liesegang bands. These structures are cemented by microporous pore-filling kaolinite (up to 18%; average: 6.6 %) as well as goethite and hematite (up to 21%; average: 3.5%). Observations from this study indicate that both depositional processes, such as grain size, and diagenetic pore-filling cements, significantly influenced the resistivity and reservoir quality of sandstones. Fine-grained sandstones containing substantial amounts of microporous kaolinite (>15%) and iron oxides (>17%) cements show very low resistivity values (≤0.2 Ω m), as well as low porosity (<10%) and very low permeability (<1 mD). Conversely, medium to coarse-grained sandstones with lower concentrations of kaolinite (<15%) and iron oxides (<5%) cements exhibited higher resistivity values (2–40 Ω m; average: 8 Ω m) and displayed higher porosity (average: 22%) and permeability (average: 1300 mD). This study underscores the importance of understanding and characterizing the presence and distribution of iron oxides and kaolinite cements, along with other factors like microporosity and grain size within LRP zones. Such understanding is crucial for accurate resistivity measurements, reservoir quality prediction, and hydrocarbon estimation in sandstone reservoirs worldwide.

High‐Throughput Exploration of Structural and Electrochemical Properties of the High‐Entropy Nitride System (Ti–Co–Mo–Ta–W)N

High‐entropy nitrides are largely unexplored materials with high potential to show good mechanical properties, high stability against chemicals, but also promising electrocatalytic properties. The latter is due to their good electrical conductivity compared to (high‐entropy) oxides. The high‐entropy nitride system (Ti–Co–Mo–Ta–W)N is chosen for investigation based on the idea to combine binary and ternary nitrides, which show good water‐splitting activities. Thin‐film materials libraries with continuous composition spreads are deposited using reactive cosputter deposition at 300 and 500 °C. X‐Ray diffraction results show that the films consist of a single‐phase solid solution in NaCl‐type structure. The surface morphology is examined using scanning electron and atomic force microscopy. (Ti–Co–Mo–Ta–W)N films show low resistivity values in the range from 1.72 to 5.2 μΩ cm. Their oxygen evolution reaction activity is measured using a scanning droplet cell, with a maximum current density of 1.78 mA cm−2 at 1700 mV versus reversible hydrogen electrode. The results indicate that stability is a challenge for high‐entropy nitrides, at least for their use as oxygen‐related electrocatalytic reactions.

MXene based electrocatalyst: CoS2@Ti3C2Tx composite for hydrogen evolution reaction in alkaline media

The worldwide need for hydrogen (H2) fuel generation through electrolysis is significant. The challenge of selecting a suitable electrocatalytic material, on the other hand, is highly complicated, since it involves discovering a stable, cost-effective choice that is widely accessible. Non-noble metal-based electrocatalysts are being studied for their potential to display attractive electrochemical water splitting (EWS) behaviour especially in alkaline media. Researchers are evaluating their ability to provide increased electrical conductivity, reduced overpotential, and greater density, which are all required for practical implementation. Herein, we present wet chemical-based synthesized MXene (Ti3C2Tx) incorporated cobalt-sulfide (CoS2) electrocatalyst for hydrogen evolution reaction (HER) in alkaline medium. As-prepared catalyst shows; very low overpotential value (286 mV) to reach 20 mA/cm2 current density, lower Tafel slope value of 78 mV/dec, higher electrochemical surface area (ECSA) 495 cm2, as well as a lower charge transfer resistance (Rct) value of 115 Ω. Such electrochemical features support this composition as a novel and robust electrocatalyst for HER toward its practical usage for energy storage and conversion systems.

Boosting the Electrocatalytic Activity of Pr0.5Ba0.5FeO3-δ via Ni Doping in Symmetric Solid Oxide Electrolysis Cells.

Symmetric solid oxide electrolysis cells (SSOECs) have garnered significant scientific interest due to their simplified cell architecture, robust operational reliability, and cost-effectiveness, for which a highly electrocatalytically active electrode is the decisive main factor. This work evaluates the electrochemical performance of Ni-doped Pr0.5Ba0.5FeO3-δ (PBF) perovskite materials, with a focus on Pr0.5Ba0.5Fe0.8Ni0.2O3-δ (PBFN). The experimental findings herein prove the exceptional electrocatalytic ability of PBFN in facilitating the oxygen evolution and carbon dioxide reduction reaction, surpassing the electrochemical performance of PBF. In addition, the PBFN symmetric cell has excellent performance for CO2 electrolysis, and the cell has a low polarization resistance value of 0.1 Ω·cm2. Moreover, it achieves an impressive current density value of 1.118 A·cm-2 under operating conditions of 2.0 V and 800 °C, which is superior to those of the PBF symmetric cell and the PBFN asymmetric cell. It also has a good structural and performance stability. These results imply a bright development prospect of PBFN as electrodes for SSOECs.

Investigation of Z-type manifold microchannel cooling for ultra-high heat flux dissipation in power electronic devices

Ultra-high heat flux (up to 1000 W/cm2) thermal management has been an urgent need for advanced power electronic devices to maintain their superior electrical performance and reliability. Embedded microchannel cooling is a promising and challenging thermal management method for high-heat-flux chips. This study presents an embedded Z-type manifold microchannel (Z-MMC) cooling design for a 5 × 5 mm2 heating zone, which can dissipate an ultra-high heat flux up to 1842 W/cm2 by using water single-phase flow. The microchannel array is etched on silicon wafer, while the manifold structure is fabricated by PDMS molding. The test chips are assembled using O2 plasma bonding technique, which provides an observation window for visualizing the flowing state of the coolant during the heat transfer process. We experimentally test and compare four test chips with different microchannel geometries and manifold designs. The average heater temperature, temperature distribution, thermal resistance, heat transfer coefficient and pressure drop are reported for mass flow rates of 2–6 g/s. The proposed Z-MMC cooler is capable of dissipating up to 1800 W/cm2 with a total thermal resistance of only 0.075 cm2·K/W (only 0.039 cm2·K/W after subtracting the conduction thermal resistance), at a flow rate of 6 g/s and a pressure drop of 54 kPa. Compared to the rectangular manifold arrangement, the trapezoidal manifold demonstrates a lower temperature rise, a more uniform temperature distribution and a smaller pressure drop at the same heat flux and flow rate, mainly due to a more uniform fluid distribution in the microchannel. Furthermore, we compare our proposed design's thermo-hydraulic performance with those of representative manifold microchannel cooling data in the literature, and the proposed Z-MMC design demonstrates relatively low thermal resistance and pressure drop values.

Synergistically coupling of trimetallic sulfides on Ni foam as porous self-supported electrodes for alkaline water splitting

The development of highly active, highly durable, and inexpensive electrode materials for water electrolysis is essential for future sustainable energy systems. Herein, we demonstrate heterostructures of metal sulfides deposited on Ni foam (NF) through electrodeposition for highly efficient water splitting. Iron-cobalt-nickel sulfides deposited on Ni foam (FeCoNiS@NF) exhibit a low overpotential of 302 mV (at 50 mA cm−2) for OER, and molybdenum-cobalt-nickel sulfides on Ni foam (MoCoNiS@NF) can provide a current density of 10 mA cm−2 at an overpotential of 114 mV for HER in alkaline solution. The lower charge-transfer resistance and Tafel slope values for FeCoNiS@NF and MoCoNiS@NF electrodes demonstrate the favorable reaction kinetics toward OER and HER, respectively, resulting from their intrinsic catalytic activity, good electrical conductivity, and accessible active sites. Furthermore, FeCoNiS@NF as anode and MoCoNiS@NF as cathode require a cell voltage of 1.68 V to produce a current density of 10 mA cm−2 with impressive durability under alkaline conditions, further proving the advancement and potential of trimetallic sulfides with optimal interfaces in the development of cost-effective electrodes for alkaline water splitting.

Geophysical investigation of pavement failure along Jonathan by-pass - Akansoko and Atimbo - Parliamentary roads in Calabar Metropolis Cross River State, Nigeria

This study examined pavement failure in some roads in Calabar Metropolis using electrical resistivity tomography method. Seven (7) measurements were taken at the natural soil opposite the failed and stable segments of the road with the aid of Wenner electrode configuration at spacing of 5.0, 10.0, 15.0, 20.0, 25.0, 30.0 and 35.0m with spread length of 105m. The findings of this study revealed that along Jonathan by- pass – Lafarge – Akansoko road, low resistivity values were 8.0Ωm – 73.0Ωm at Akansoko a stable segment; 6.0Ωm - 17.0Ωm at Ukwua Itiat and 30.0Ωm - 94.0Ωm at Idundu market a failed segment. Along Atimbo - Jonathan – Parliamentary road, moderate/high electrical resistivity values in the range 331.0 Ωm – 1018.0 Ωm across the profile was obtained at Federal Government Girls’ College by airport a control segment; 26.0 Ωm – 68.0 Ωm at opposite rice seedling site a failed segment and 49.0 Ωm – 74.0 Ωm at Message point Assembly Church. These results showed that the remote cause of road failure in the area is clay/shale/weathered geologic materials with low resistivity values. It was recommended that detailed geophysical investigation should always be conducted on any proposed site for road construction and/or rehabilitation before embarking on the project.

Subsurface Identification using Resistivity Method for Infrastructure Planning in Benowo Area, Surabaya City

Subsurface rock identification in infrastructure construction is important to get the information in planning and monitoring the rock carrying capacity and groundwater systems for infrastructure construction. To get the subsurface condition information that are relatively shallow with detailed results, Resistivity method with Wenner configuration is used. Research is in Benowo area, where dominated by pond area. This research used 5 Resistivity lines, which are divided into 2 locations separated by distance of about 2400 meters as Z1 and Z2 areas. For the subsurface resistivity section at Z1 area there are 2 lines, while at Z2 area there are 3 lines. It is known at Z1 area, top layer is topsoil (2.26-33.00 Ωm) and the bottom layer was identified as clay (0.30-2.26 Ωm). At Z2, top layer being topsoil (0.306-0.708 Ωm), followed by clay layer (0.100-0.306 Ωm), and the sand layer (0.231-0.535 Ωm) in the bottom of resistivity model. Groundwater system shows topsoil acts as a vadose zone, clay layer acts as an aquiclude and the sand layer acts as an unconfined aquifer. Saturated water influences the low resistivity value measurement related to the environmental condition dominated by pond area, beside measurements in rainy season are also suspected to be the cause of low resistivity measured. To be applied infrastructure development in the Benowo area need further treatment activity like soil and/or rock pavement to support infrastructure safety. This research result is related to geotechnical aspects like rock coring, pavement, and optimum architectural design can be an alternative for further research.

Numerical Study on Resistance of Stepped Planing Hull

A stepped planing hull, also known as a step hull, is a hull modification that reduces the wetted surface area. Although this type of hull has proven effective in several ships, it is still rarely used. The step hull possesses numerous advantages that make it ideal for activities involving small and fast boats. However, regrettably, its full potential remains untapped at present. The purpose of this study was to identify the effect of variations in the angle of the step hull on resistance or drag. The study utilized the CFD method, and three hull configuration models were used at each change in hull step angle of 180º, 210º, 240º, and 270º. Configurations 1 and 2 have similarities in terms of rear hull length (600 mm), hull height (20 mm for configuration 1 and 30 mm for configuration 2), and deadrise angle (15° for configuration 1 and 20° for configuration 2). Configuration 3 has similarities with an 800 mm rear hull, 20 mm hull height, and 15° deadrise angle. It was found that as the Froude number increases, the coefficient of total resistance decreases. Conversely, as the Froude number increases, the resulting resistance also increases. The configuration with the highest resistance value corresponds to the alteration from configuration 2 with a hull step of 180°, and that the alteration from configuration 2 with a hull step of 270° corresponds to the configuration with the lowest resistance value. This study concludes that deadrise angle and the height of the step hull are the main factors that require careful consideration when designing ships that use a step hull. Therefore, this research provides an understanding of the step hull and can serve as a basis for the development of the step hull.

Electrical and microstructural characterization of carbon nanotube-carbon fiber added cementitious conductive surface coating

In contrast to the traditional methods of directly adding conductive fillers to the cement matrix in the development of heatable conductive concrete, radiation shielding and smart sensing cementitious materials, this study proposes a more efficient approach by covering the non-conductive glass fiber reinforced concrete (GRC) surface with a thin conductive layer. Single-walled carbon fiber (SWCNT) and carbon fiber (CF) were used as conductive additives in the mixture of electrically conductive surface coating. Dosages of 0.1%, 0.2%, and 0.3% (wt) for SWCNT and 0.2%, 0.4%, 0.6%, 0.8%, and 1% (Vol) for CF were preferred. According to these ratios, a total of 15 different conductive cement coatings were carried out. White Portland cement and fine silica sand were used as binder and filler material, respectively. The conductive cement-based coating with a thickness of approximately 3 mm shows good adhesion and integration properties, since it is placed in the mold gradually at the same time as the GRC, which acts as the substrate. Resistivity, impedance, heatability (electrothermal), TGA-DTA and microstructure characterization were performed to investigate the electrical, thermal and microstructural properties of the coatings.The impedance/resistance properties of the cement-based composite samples containing CF showed superior performance compared to the other samples. In TGA/DTA analyses, the amount of CF in the cement mixture did not affect the thermal weightlossmuch. The lowest resistivity values were measured as 20 and 80 Ω.cm for the CF1.0 and CF0.8 samples, respectively, and the electrothermal test results showed that the temperature reached 45.5 and 28 °C from 23 °C, respectively, by applying 24 V voltage within 1 h with a power consumption of 750 W/m2 and 232 W/m2.

Does the peroral chromium administration in young Hariana calves reduce the risk of calf diarrhea by ameliorating insulin response, lactose intolerance, antioxidant status, and immune response?

BackgroundThe reduction in insulin sensitivity during rumen development may predispose dairy calves towards lactose intolerance, which could be the reason behind neonatal calf diarrhea (NCD). Chromium (Cr) results in a range of effects when fed to ruminants, but most studies have shown improved insulin sensitivity. The aim of this study was to determine the effect of Cr supplementation on insulin sensitivity, lactose intolerance, diarrhoea and antioxidant, and immune response in young Hariana calves. MethodsA total of 20 milk-fed Hariana calves were randomly assigned to 1 of 2 treatments, each consisted of 10 calves: (1) a control group without supplemental Cr and (2) a 0.15 mg Cr as Cr-picolinate (CrPic)/kg BW0.75 supplemented group (Cr0.15). ResultsA more rapid glucose disappearance with unaltered insulin kinetics during intravenous glucose tolerance test (IVGTT) and oral lactose tolerance test (OLTT) indicates greater insulin sensitivity in Cr supplemented calves. Better insulin sensitivity in Cr supplemented calves was further confirmed by higher values of the quantitative insulin sensitivity check index (QUICKI), revised quantitative insulin sensitivity check index (RQUICKI) and insulin receptor substrate-1 (IRS-1) and lower (P < 0.05) values of homeostasis model assessment-insulin resistance (HOMA-IR) and glucose-to-insulin ratio in Cr supplemented calves during IVGTT. Cr supplementation resulted in a lower (P < 0.05) serum cortisol concentration, whereas serum non-esterified fatty acid (NEFA) concentrations during IVGTT did not differ among the groups. The rise in serum glucose concentrations within 2 h post lactose infusion during OLTT peaked at more than twice the basal glucose concentration, therefore calves were not considered as lactose intolerant. Within monthly blood samples, concentrations of serum insulin were similar among treatments, whereas the Cr supplemented group had lower (P < 0.05) serum glucose concentration and glucose-to-insulin ratio compared with the control group. No treatment differences were detected in the biomarkers of antioxidant status and immunity. Serum Cr concentrations were higher (P < 0.05) in Cr supplemented calves while concentrations of other studied minerals were remained unaltered. The incidence, duration of diarrhea, and faecal score were better (P < 0.05) in calves fed on Cr supplemented diet whereas, no treatment effect was observed on average daily gain (ADG). During the study period, no calves died, and no calves were found to have pneumonia, navel or joint disease. ConclusionFeeding a Cr-supplemented diet improved insulin sensitivity and reduced the risk of diarrhoea in milk-fed young calves, but had no or minimal effects on lactose intolerance, antioxidant status, immune response, and growth performance.

Sub-surface configuration in the northern part of Lembang groundwater basin recharge area

Lembang groundwater basin has an area of 209 km2. Increased tourism activities in the Lembang Groundwater Basin require sufficient groundwater resources to support the sustainability of these tourism activities. The purpose of this study was to analyze the hydrostratigraphy of the groundwater recharge zone of the Lembang groundwater basin in the Cikole-Lembang. Electrical Resistivity Tomography (ERT) with dipole–dipole electrode array and seismic refraction was used to analyze the hydrostratigraphy. The results of ERT and seismic refraction inversion show that Tangkubanparahu Pyroclastic Fall 2 can be characterized as aquifers. This layer consists of low (123–292 Omega m) and intermediate (293–700 Omega m) resistivity value and also has low (300–1350 m/s) to medium (2700–1350 m/s) velocity. Tangkubanparahu lava (Tl) layer has a high resistivity value (701–3875 Omega m) and high (1350–2999 m/s) velocity. The Tangkubanparahu Pyroclastic Fall 1 has a resistivity of 300–700 ohms. Tangkubanparahu (Tl) lava deposits can be characterized as fracture aquifer and impermeable layers in the Tangkubanparahu volcanic hydrogeological system depend on the historical structural geology event.