The Gypsum Influence on the Formation of Secondary Phases During Autoclave Leaching of Gold-Bearing Concentrates and the Silver Recovery Using Cyanidation.

Autoclave leaching of sulfide concentrates may produce various ferric secondary phases, depending on the arsenic content and temperature. Silver is converted to argentojarosite, from which it is not recoverable by standard cyanidation methods. To increase silver recovery, it is necessary to reduce the argentojarosite formation during autoclave leaching.

The Dissolution Behavior of Pyrite and Chalcopyrite During Low-Temperature Pressure Oxidation: Chalcopyrite Influence on Pyrite Oxidation.

The research of this paper was carried out on the low-temperature (100 ± 2 °C) pressure (0.2-0.8 MPa) leaching of pyrite, chalcopyrite and their mixture.

Fabrication and Investigation of Deformable Rubber-Carbon Nanotube-Glue Gel-Based Impedimetric and Capacitive Tactile Sensors for Pressure and Displacement Measurements.

Carbon nanotube-glue composite gel-based surface-type elastic sensors with a cylindrical shape deformable (flexible) metallic body were fabricated for tactile pressure and compressive displacement sensing. The fabrication of the sensors was performed using the rubbing-in technique. The effect of the pressure and the compressive displacement on the capacitance and the impedance of the sensors were investigated at various frequencies (in the range of 1 kHz to 200 kHz).

An algorithm for computing Schubert varieties of best fit with applications.

We propose the geometric framework of the Schubert variety as a tool for representing a collection of subspaces of a fixed vector space. Specifically, given a collection of -dimensional subspaces , …, of ℝ, represented as the column spaces of matrices , …, , we seek to determine a matrix ∈ℝ such that each subspace intersects (or comes close to intersecting) the span of the columns of in at least dimensions. We formulate a non-convex optimization problem to determine such a along with associated sets of vectors {} and {} used to express linear combinations of the columns of the that are close to linear combinations of the columns of .

Orange Dye and Silicone Glue Composite Gel-Based Optimized Impedimetric and Capacitive Surface-Type Proximity Sensors.

Optimized surface-type impedimetric and capacitive proximity sensors have been fabricated on paper substrates by using rubbing-in technology. The orange dye (OD) and silicone glue (SG) composite-gel films were deposited on the zig-zag gap between two aluminum electrodes fixed on a paper (dielectric) substrate. The effect of proximity of various objects (receivers) on the impedance and the capacitance of the sensors was investigated.

Fabrication and Investigation of Graphite-Flake-Composite-Based Non-Invasive Flex Multi-Functional Force, Acceleration, and Thermal Sensor.

This work examines the physics of a non-invasive multi-functional elastic thin-film graphite flake-isoprene sulfone composite sensor. The strain design and electrical characterization of the stretching force, acceleration, and temperature were performed. The rub-in technique was used to fabricate graphite flakes and isoprene sulfone into sensors, which were then analyzed for their morphology using methods such as SEM, AFM, X-ray diffraction, and Fourier transform infrared spectroscopy to examine the device's surface and structure.

Development of a Two-Stage Hydrometallurgical Process for Gold-Antimony Concentrate Treatment from the Olimpiadinskoe Deposit.

An integrated two-stage metallurgical process has been developed to process concentrates from the Olimpiadinskoe deposit, which contain high levels of antimony and arsenic. The optimal parameters for the alkaline sulfide leaching process of the initial concentrate from the Olimpiadinskoe deposit were determined to achieve the maximum extraction of antimony at a 99% level. The recommended parameters include an L:S ratio of 4.

Shockproof Deformable Infrared Radiation Sensors Based on a Polymeric Rubber and Organic Semiconductor HPc-CNT Composite.

Polymeric rubber and organic semiconductor HPc-CNT-composite-based surface- and sandwich-type shockproof deformable infrared radiation (IR) sensors were fabricated using a rubbing-in technique. CNT and CNT-HPc (30:70 wt.%) composite layers were deposited on a polymeric rubber substrate as electrodes and active layers, respectively.

Synthetic Sulfide Concentrate Dissolution Kinetics in HNO Media.

The nature of tennantite (Cu12As4S13), chalcopyrite (CuFeS2) and sphalerite (ZnS) particles’ mixture dissolution in nitric acid (HNO3) media was investigated in this study. The effects of temperature (323−368 K), HNO3 (1−8 mol/L) and Fe3+ (0.009−0.

Effect of Vibrations, Displacement, Pressure, Temperature and Humidity on the Resistance and Impedance of the Shockproof Resistors Based on Rubber and Jelly (NiPc-CNT-Oil) Composites.

Here, we present the design, fabrication and characterization of shockproof rubber-jelly (NiPc-CNT-oil) composite-based resistors. To fabricate the resistors, gels of CNT and NiPc with edible oil were prepared and deposited on a flexible rubber substrate using rubbing-in technique. The devices' resistance and impedance were investigated under the effect of pressure, displacement, humidity, temperature and mechanical vibrations.

Nitric Acid Dissolution of Tennantite, Chalcopyrite and Sphalerite in the Presence of Fe (III) Ions and FeS.

This paper describes the nitric acid dissolution process of natural minerals such as tennantite, chalcopyrite and sphalerite, with the addition of Fe (III) ions and FeS. These minerals are typical for the ores of the Ural deposits. The effect of temperature, nitric acid concentration, time, additions of Fe (III) ions and FeS was studied.

Ultraviolet and Infrared Irradiations Sensing of Gel-Orange Dye Composite-Based Flexible Electrochemical Cells.

The flexible and shockproof rubber-based Al/OD-Gel/Cu electrochemical cell was designed, fabricated, and investigated for the detection of IR and UV irradiations. For this purpose, the transparent gel-orange dye composite was deposited on the porous rubber substrate between aluminum and copper electrodes. It was observed that the gel-orange dye composite was mechanically like a gel: soft and flexible.

Effect of Humidity and Temperature on the Impedances and Voltage of Al/Gr-Jelly/Cu-Rubber Composite-Based Flexible Electrochemical Sensors.

Here we present the fabrication of graphene and jelly (superabsorbent polymer) electrolyte composite-based shockproof flexible electrochemical sensors (Al/Gr-Jelly/Cu) and their properties under the effect of humidity and temperature. A layer of graphene mixed in jelly electrolyte was drop-casted onto porous rubber substrates between preliminary fixed aluminum (Al) and copper (Cu) electrodes followed by rubbing-in. It was observed that the graphene and jelly mixture was mechanically soft and flexible, similar to jelly.

Corrosion Behavior of Candidate Functional Materials for Molten Salts Reactors in LiF-NaF-KF Containing Actinide Fluoride Imitators.

Molten fluorides of alkali metals are considered a technological medium for molten salt reactors (MSRs). However, these media are known to be extremely corrosive. The successful implementation of high-temperature technological devices using molten alkali metal fluorides requires the selection of such structural materials that have high corrosion resistance in melts with compositional characteristic of MSRs.

An ensemble framework based on Deep CNNs architecture for glaucoma classification using fundus photography.

Glaucoma is a chronic ocular degenerative disease that can cause blindness if left untreated in its early stages. Deep Convolutional Neural Networks (Deep CNNs) and its variants have provided superior performance in glaucoma classification, segmentation, and detection. In this paper, we propose a two-staged glaucoma classification scheme based on Deep CNN architectures.

Improving the efficiency of corn drying in a conveyor belt dryer.

The paper deals with the theoretical background of drying corn kernels in the moving bed. The authors present a system of the drying medium (drying air) uniform distribution in the dryer. They proposed a system that can improve the performance of the conveyor dryer.

Noise Cancellation of Helicopter Blade Deformations Measurement by Fiber Bragg Gratings.

The work presents data treatment methods aimed at eliminating the noise in the strain sensor data induced by vibrations of the helicopter blade in flight conditions. The methods can be applied in order to enhance the metrological performance of the helicopter weight estimation system based on the deformation measurement of the main rotor blades. The experimental setup included a composite plate fixed to the vibrating stand on the one end, with six fiber-optic strain sensors attached to its surface.

A Novel Poly-N-Epoxy Propyl Carbazole Based Memory Device.

Generally, polymer-based memory devices store information in a manner distinct from that of silicon-based memory devices. Conventional silicon memory devices store charges as either zero or one for digital information, whereas most polymers store charges by the switching of electrical resistance. For the first time, this study reports that the novel conducting polymer Poly-N-Epoxy-Propyl Carbazole (PEPC) can offer effective memory storage behavior.

Algorithm of FBG Spectrum Distortion Correction for Optical Spectra Analyzers with CCD Elements.

Nonlinear spectrum distortions are caused by the peculiarities of the operation of charge-coupled device elements (CCD), in which the signal exposition time (Time of INTegration-TINT) is one of the significant parameters. A change of TINT on a CCD leads to a nonlinear distortion of the resulting spectrum. A nonlinear distortion of the spectrum, in turn, leads to errors in determining the central wavelength of fiber Bragg gratings (FBGs) and spectrally sensitive sensors, which, in general, negatively affects the accuracy of the measuring systems.

A novel and stable ultraviolet and infrared intensity sensor in impedance/capacitance modes fabricated from degraded CHNHPbI-Cl perovskite materials.

The present situation of COVID-19 diverted our focus towards utilizing the degraded solar cells for sensor application, this will help in global energy harvesting. So, here is our successful effort to reuse already degraded solar cells as ultraviolet (UV) and infrared (IR) sensor. The spin-coated perovskite (CHNHPbICl) has been already tested for visible light spectrum, as an extension to that now it is utilized as UV and IR intensity sensors to cover the whole spectrum.

A novel and stable way for energy harvesting from BiTeSe alloy based semitransparent photo-thermoelectric module.

In this research, due to the present pandemic of COVID-19, we are proposing a stable and fixed semitransparent photo-thermoelectric cell (PTEC) module for green energy harvesting. This module is based on the alloy of Bismuth Telluride Selenide (BiTeSe), designed in a press tablet form and characterized under solar energy. Here, both aspects of solar energy i.

Decade of 2D-materials-based RRAM devices: a review.

Two dimensional (2D) materials have offered unique electrical, chemical, mechanical and physical properties over the past decade owing to their ultrathin, flexible, and multilayer structure. These layered materials are being used in numerous electronic devices for various applications, and this review will specifically focus on the resistive random access memories (RRAMs) based on 2D materials and their nanocomposites. This study presents the device structures, conduction mechanisms, resistive switching properties, fabrication technologies, challenges and future aspects of 2D-materials-based RRAMs.

Fabrication of flexible conductive films by rubbing in technology for application in elastic thermo-electric cells.

This method solves the problem of fabrication of flexible elastic conductive thin film samples for thermoelectric applications. For this purpose, rubbing in technology at room temperature condition has been used which is simple, economical and reliable. As a result, elastic thermo-electric cells have been fabricated that can be used for low power applications and for measurement of the gradient of temperature in industry, medicine and in instrumentation as well.

Elastic layered rubber-graphene composite fabricated by rubbing-in technology for the multi-functional sensors.

In this work, the elastic layered rubber-graphene composite based multi-functional sensor has been fabricated by rubbing-in technology. The effects of temperature, displacement, pressure and humidity on the impedance of the multi-functional sensor has been investigated in the frequency range of 0-200 kHz. The impedance of the samples decreased under the effect of uniaxial compressive displacement and under the effect of pressure.

Responses of snow leopards, wolves and wild ungulates to livestock grazing in the Zorkul Strictly Protected Area, Tajikistan.

Long recognized as a threat to wildlife, livestock grazing in protected areas has the potential to undermine conservation goals, via competition, habitat degradation, human-carnivore conflict and disruption of predator-prey relationships. In the Strictly Protected Area Zorkul in Tajikistan (Zorkul Reserve), grazing is commonplace despite official prohibition, with potentially detrimental effects on local fauna, in particular, snow leopard Panthera uncia, wolf Canis lupus, brown bear Ursus arctos, argali sheep Ovis ammon, Asiatic ibex Capra sibirica, and long-tailed marmot Marmota caudata. To understand the impacts of grazing and associated human pastoralism on the large mammal community in Zorkul Reserve we used data from camera traps to build models of ungulate and carnivore site use intensity, and we investigated carnivore summer diets using microscopic scat analysis.