Effectiveness of Geo-Energy Usage during Underground Mining of Deposits

Topicality of rock pressure energy usage in technologies of underground mining of deposits is revealed. Methodology of geo-energy processes research in the interior of the Earth is described. Energy theory of zonal capsulation parameters research by massif of underground workings is proposed. Results verification of theoretical research is executed by laboratory and industrial tests conducting. Economic and mathematical model of determination of unit costs on types of mining operations is substantiated and volumes of savings during usage of geo-energy during mining operations conducting are determine

Influence of sodium alginate on the formation of the structure of the products from chopped and minced meat

The paper presents the results of using algae as a natural additive to chopped semi-finished meat products. The optimal ratio is set by means of the design method and the results of organoleptic assessment. The mathematical models that help to determine the optimal values of the factors and C, W and T (concentration of the components, moisture content and duration of mincing) are obtaine

Procedure of computation and automatic marking of drill hole spacing at excavation of horizontal workings

Contemporary approaches and techniques impacting subsurface penetration performance and penetration rate are studied and analyzed. Two main dimensions are identified, and the works performed during operation were compared. A solution based on implementation of modular architecture of the system with optional connection of modules, performing computations according to various techniques, enabling comparison of calculation results and selection of the most effective option, is proposed. A computational experiment based on real-objects data was conducted. The factors effecting drilling-and-blasting operations were identified during its course. A model designing the optical projections over targeted drill holes is also obtained. The proposed approach is more effective and accurate than manual application of drill hole spacing by paint; in addition, is saves a lot of time required for setting-up. Another highlighted advantage of the developed approach is high quality and accuracy at marking of the drill hole spacing for blasting pattern in accordance with geometrical features of the surfaces, vs. approaches and techniques used at preparation to drilling earlier. Aside from that, a clear trend of consistent improvement and perfection by means of application of intelligent algorithm is observed in this scope

Economic and environmental aspects of using mining equipment and emulsion explosives for ore mining

The calculation of economic efficiency during the preparatory mine operations using various mining equipment and types of explosives was performed. The general exponential regularity of determining the cost of carrying out 1 m3 of working depending on the strength of rocks to compression when using different types of explosives and tunneling equipment was established. An environmental assessment of the use of emulsion explosives in an iron ore mine showed a decrease in concentrations of environmentally hazardous substances and a decrease in environmental hazard coefficients, which resulted in a decrease in the pollution of the atmospheric air

Multiple Resistive Switching Mechanisms in Graphene Oxide-Based Resistive Memory Devices

Among the different graphene derivatives, graphene oxide is the most intensively studied material as it exhibits reliable and repeatable resistive switching. The operative mechanisms that are responsible for resistive switching are being intensively investigated, and three models explaining the change in the resistive states have been developed. These models are grounded in the metallic-like filamentary conduction, contact resistance modification and the oxidation of/reduction in the graphene oxide bulk. In this work, using Al/GO/n-Si structures, we demonstrate that all three of these operative mechanisms can simultaneously participate in the resistive switching of graphene oxide. Multiple point-like conduction channels in the graphene oxide films were detected by the electron beam-induced current (EBIC) technique. At the same time, large areas with increased conductivity were also revealed by EBIC. An analysis of these areas by Raman spectroscopy indicates the change in the graphene oxide bulk’s resistive properties. The EBIC data along with the measurements of the capacitance–voltage characteristics provided strong evidence of the involvement of an aluminum/graphene oxide interface in the switching processes. In addition, by using Al/GO/n-Si structures, we were able to identify unique local properties of the formed conductive channels, namely the change of the charge state of a conductive channel due to the creation of negatively charged traps and/or an increase in the GO work function

Diamond Photoconductive Antenna for Terahertz Generation Equipped with Buried Graphite Electrodes

It has been shown recently that a photoconductive antenna (PCA) based on a nitrogen-doped diamond can be effectively excited by the second harmonic of a Ti:sapphire laser (λ = 400 nm). The THz emission performance of the PCA can be significantly increased if a much stronger electric field is created between the close-located electrodes. To produce a homogeneous electric field over the entire excited diamond volume, the laser fabrication of deep-buried graphite electrodes inside the diamond crystal was proposed. Several electrodes consisting of the arrays of buried pillars connected by the surface graphite stripes were produced inside an HPHT diamond crystal using femtosecond and nanosecond laser pulses. Combining different pairs of the electrodes, a series of PCAs with various electrode interspaces was formed. The THz emission of the PCAs equipped with the buried electrodes was measured at different values of excitation fluence and bias voltage (DC and pulsed) and compared with the emission of the same diamond crystal when the bias voltage was applied to the surface electrodes on the opposite faces. All examined PCAs have demonstrated the square-law dependencies of the THz fluence on the field strength, while the saturation fluence fluctuated in the range of 1200–1600 µJ/cm2. The THz emission performance was found to be approximately the same for the PCAs with the surface electrodes and with the buried electrodes spaced at a distance of 1.4–3.5 mm. However, it noticeably decreased when the distance between the buried electrodes was reduced to 0.5 mm

Diamond Detector With Laser-Formed Buried Graphitic Electrodes: Micron-Scale Mapping of Stress and Charge Collection Efficiency

The paper reports the micron-scale investigation1 of an all-carbon detector based on synthetic single crystal2 CVD-diamond having an array of cylindrical graphitic buried-3 contacts, about 20 µm in diameter each, connected at the4 front side by superficial graphitic strips. To induce diamond-5 to-graphite transformation on both detector surface and bulk6 volume, direct-laser-writing technique was used. Laser-treatment7 parameters and cell shape have been chosen to minimize the over-8 lapping of laser-induced stressed volumes. Optical microscopy9 with crossed polarizers highlighted the presence of an optical10 anisotropy of the treated material surrounding the embedded11 graphitized columns, and non-uniform stress in the buried12 zones being confirmed with a confocal Raman spectroscopy13 mapping. Dark current-voltage characterization highlights the14 presence of a field-assisted detrapping transport mainly related15 to highly-stresses regions surrounding buried columns, as well as16 superficial graphitized strips edges, where electric field strength17 is more intense, too. Notwithstanding the strain and electronic-18 active defects, the detector demonstrated a good charge collection19 produced by 3.0 and 4.5 MeV protons impinging the diamond,20 as well as those generated by MeV β-particles emitted by 90Sr21 source. Indeed, the mapping of charge collection efficiency with22 Ion Beam Induced Charge technique displayed that only a few23 micrometers thick radial region surrounding graphitic electrodes24 has a reduced efficiency, while most of the device volume25 preserves good detection properties with a charge collection26 efficiency around 90% at 60 V of biasing. Moreover, a charge27 collection efficiency of 96% was estimated under MeV electrons28 irradiation, indicatingthe good detection activity along theburied29 columns dept

Efficiency of Photoconductive Terahertz Generation in Nitrogen-Doped Diamonds

The efficiency of the generation of terahertz radiation from nitrogen-doped (∼0.1–100 ppm) diamonds was investigated. The synthetic polycrystalline and monocrystalline diamond substrates were pumped by a 400 nm femtosecond laser and tested for the photoconductive emitter operation. The dependency of the emitted THz power on the intensity of the optical excitation was measured. The nitrogen concentrations of the diamonds involved were measured from the optical absorbance, which was found to crucially depend on the synthesis technique. The observed correlation between the doping level and the level of the performance of diamond-based antennas demonstrates the prospects of doped diamond as a material for highly efficient large-aperture photoconductive antennas

Efficiency of Photoconductive Terahertz Generation in Nitrogen-Doped Diamonds

The efficiency of the generation of terahertz radiation from nitrogen-doped (∼0.1–100 ppm) diamonds was investigated. The synthetic polycrystalline and monocrystalline diamond substrates were pumped by a 400 nm femtosecond laser and tested for the photoconductive emitter operation. The dependency of the emitted THz power on the intensity of the optical excitation was measured. The nitrogen concentrations of the diamonds involved were measured from the optical absorbance, which was found to crucially depend on the synthesis technique. The observed correlation between the doping level and the level of the performance of diamond-based antennas demonstrates the prospects of doped diamond as a material for highly efficient large-aperture photoconductive antennas