bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-dimensional modeling of pendulum waves propagation under dynamic loading of underground excavation surface
Authors: Aleksandrova NI 
Published: May 2021

Abstract
The propagation of surface pendulum waves under nonstationary loading on the free surface of a cavity located in a block half-space is studied numerically. A mathematical model of transient viscoelastic deformation of the block medium is proposed. This model is based on the idea that dynamic behavior of the block medium can be approximately described as the movement of rigid blocks due to the compliance of interlayers between them. To describe the viscoelastic behavior of the interlayers, an internal friction model is used with the merit factor of the material as the determining parameter. The medium is modeled by a three-dimensional lattice of masses connected by elastic springs and viscous dampers in axial and diagonal directions. The influence of the merit factor and the cavity depth on the amplitudes of block velocities on the surface of the half-space is investigated for the longitudinal and Rayleigh waves.
Study of regularities of changes in stress-strain state of coal–rock mass in fractured zones
Authors: Demin VF , Nemova NA 
Published: May 2021

Abstract
The regularities of changes in the stress-strain state of coal in rock mass depending on the main mining geological and engineering factors are identified. Using these factors, it is possible to find the optimal support parameters in specific conditions to increase the stability of preparatory mine workings. The degree of influence of mining and engineering conditions of exploitation on displacements in marginal rocks with various types of support in excavation workings is investigated.
Ultimate pressure determination in hydraulic fracturing of boreholes for different rock failure criteria
Authors: Kovrizhnykh AM , Kurlenya MV 
Published: May 2021

Abstract
The problem on elastoplastic deformation and rock failure around boreholes under the action of internal pressure is considered. The stress state in the intact rock mass is assumed to be hydrostatic. The hydraulic fracturing pressure is conventionally determined by the maximum normal stress criterion. However, the experimental studies described in scientific articles show that this criterion is not consistent with the results obtained in the course of laboratory tests on failure of cylindrical and spherical cavities made in rock samples. It has been known that test results on complex loading for solid samples of various materials are not confirmed by the theory of maximum normal stress both in terms of ultimate load value and direction of failure surface propagation. In this case, for the complex stress state of rocks, it is proposed to determine the ultimate pressure by the experimentally substantiated fracture criteria which are in good agreement with the results of laboratory tests on hydraulic fracturing of boreholes.
Effect of the proppant on fracture compressibility in coal seam
Authors: Shilova TV 
Published: May 2021

Abstract
The paper discusses enhancement of gas drainage well productivity in coal seams using the hydraulic fracturing technology. Filling of a fracture with proppant provides a long-term increase in the gas drainage well performance. The results of the laboratory experiments to determine coal permeability under various stress conditions show that proppants significantly reduce fracture compressibility and the propped fracture becomes less sensitive to stress variations.
Determination of shapes and sizes of radial cracks formed by blasthole charges and hydraulic fracturing in a layered rock mass
Authors: Sher EN 
Published: May 2021

Abstract
The features are investigated and a design diagram is developed for radial cracks propagation in a layered rock mass during blasting of borehole charges and hydraulic fracturing. To calculate the stress state of an elastic rock mass with cracks, we used the boundary element method in a three-dimensional formulation. As a result of these calculations, the influence of the strength properties of rock mass layers on the shape of radial cracks and their area was determined.
Effect of elastic valve characteristics on pneumatic impact ring machine capacity
Authors: Primychkin AYu , Belozertseva LYu 
Published: May 2021

Abstract
The paper presents a case-study of the effect exerted by a ring-shaped elastic valve as a promising lock-and-control element of air distribution on the performance of a pneumatic impact ring machine. The design model of the machine is presented. The authors determine the blow energy and frequency of the machine, as well as the compressed air flow rate versus the preload of the valve and the elasticity modulus of the valve material. The recommendations on design of the elastic air distribution elements for pneumatic percussion machines subject to their operational conditions are given.
Dynamics of gravity-type pneumatic percussion machine for drain hole drilling
Authors: Tambovtsev PN 
Published: May 2021

Abstract
The author presents and justifies a construction diagram of a gravity-type pneumatic percussion machine for drain hole drilling with efficient penetration of casing in soil. The working cycle parameters of the machine, efficient design variables, as well as the blow energy, blow frequency and compressed air flow rate depending on the line pressure are determined by the numerical modeling. The weight, size and dynamics of the gravity-type machine are compared with the known analogous facilities.
Physical properties and fracture behavior of rocks in uniaxial and triaxial compression: A case-study of Zhdanovskoe deposit, Kola Mining and Metallurgical Company
Authors: Zemtsovsky AV , Kuznetsov NN , Pak AK 
Published: May 2021

Abstract
The paper presents the test data on properties of rocks from Zhdanovskoe deposit located in the Pechenga area of the Murmansk Region. The nature of the elastic energy accumulation in rock specimens and their susceptibility to uncontrollable fracture in the dynamic mode are determined. The uniaxial and triaxial compression test data are used to find mechanical properties and energy characteristics of rock specimens. The tested rocks are assessed as hard and susceptible to dynamic fracture, which is one of the criteria of rockburst hazard.
3D probabilistic cellular automation modeling of transition to fracture in rocks under loading
Authors: Kazunina GA , Cherednichenko AV 
Published: May 2021

Abstract
The three-dimensional model of the probabilistic cellular automaton, which has previously been constructed on the basis of the kinetic theory of strength, is studied in this paper. It describes the process of rock damage accumulation and formation of a damage cluster structure. Comparing the kinetic curves of damage accumulation and correlation functions of the model experiments, it is found that, depending on the sprouting probability of the damage cluster perimeter, which simulates the rate of material fracture under the action of local overstresses near the existing damage clusters, two qualitatively different modes of damage accumulation are observed in the 3D model. For the sprouting probabilities of the cluster perimeter higher than 0.2, the process of transition to irreversible fracture is significantly accelerated and becomes strongly correlated. Along with this, the best agreement of correlation functions in the model and in the physical experiments is observed for the sprouting perimeter probability values smaller than 0.2.
Improvement of technology and procedures of local rockburst hazard control
Authors: Tereshkin AA , Rasskazov IYu , Anikin PA , Gladyr AV , Migunov DS , Rasskazov MI 
Published: May 2021

Abstract
At some rockburst-hazardous deposits in Russian Far East and on the Kola Peninsula, the measurement of acoustic emission parameters is performed, and new data are obtained on hazardous features of confining pressure in different sites of mine fields. The measurement procedure is developed for local ground pressure control Prognoz L, and additional rockburst hazard criteria are substantiated for underground mines.
Tests of centrifugal concentrator in processing of diamond-bearing sand with co-current gold recovery
Authors: Ochosov OYu , Matveev AI 
Published: May 2021

Abstract
The data are reported on the co-current gold recovery in the process for beneficiation of diamond-bearing sands from a number of deposits developed by Almazy Anabara Co. The company conducts co-current gold recovery at standard sluice facilities. The comparative data on gold recovery at Itomak centrifugal concentrator and a centrifugal-vibration concentrator (CVC), designed at IGDS SB RAS, are cited in the present paper. It is proved that CVC capacity allows as high as 92.8% gold recovery.
Finishing of gold-bearing concentrated products
Authors: Salomatova SI 
Published: May 2021

Abstract
The research data on the finishing centrifugal flotation of the pre-concentrated gold-antimony ore product are reported on a series of laboratory tests at a centrifugal flotation machine with peripherical discharge of the concentrate (CFM) and a mechanical flotation machine (FM). The selectivity of mineral particle detachment from the mineralized flotation froth moving along an inclined plane after flotation process running at different modes with/without a collector. It is demonstrated that the use of a collector makes it possible to control intensity and selectivity of material detachment from the froth layer. It is found that flotation finishing in the centrifugal flotation machine actually enables to improve the final concentrate characteristics.
Sintered Fe-Cr-Mo-Si-C alloys produced from pre-alloyed Fe-Cr based powders admixed with 4% SiC for high performance applications
Authors: Soe A.N. , Wila P. , Morakotjinda M. , Yotkaew T. , Karin P. , Ohtake N. , Tongsri R. 
Published: May 2021

Abstract
The use of pre-alloyed Fe-Cr based powders has been steadily increasing in the automotive industry. Mechanical properties can be tailored due to phase transformations controlled by alloying elements and cooling rates. Employing silicon carbide (SiC) as a source of alloying elements has been proved to be possible. In this study, three different pre-alloyed Fe-Cr based powders, namely Astaloy CrA, Astaloy CrL, and Astaloy CrM, were alloyed with 4 wt. % SiC powder. The powders were mixed and pressed into tensile test bars. The green compacts were sintered at 1250 °C for 45 minutes under the cracked ammonia gas and slowly cooled (<0.1°C/s) to room temperature. All experimental sintered alloys manifested a common feature resembling those of full pearlitic ductile irons, i.e., the feature consisted of black nodular particles enveloped with hyper-eutectoid steel matrix (grain boundary or pro-eutectoid cementite plus pearlite). The tensile testing indicated that Alloy-3 (Astaloy CrM + 4%SiC) was observed to have better mechanical properties in comparison with Alloy-1 (Astaloy CrA + 4%SiC) and Alloy-2 (Astaloy CrL + 4%SiC), apart from slightly lower elongation than Alloy-2. Regardless of SiC addition, the presence of chromium (Cr) content was observed to substantially influence mechanical properties and microstructure. According to the investigation of fracture surfaces by SEM, mixtures of shallow dimples and cleavage fractures were examined in the sintered alloys.
The effect of molybdenum on the microstructure and mechanical behaviour of the sintered Fe-Mo-Mn-Si-C composite
Authors: Nithimethakul Thunyamon , Karin Preechar , Ohtake Naoto , Wila Pongsak , Yodkaew Thanyaporn , Vetayanugul Bhanu , Morakotjinda Monnapas , Tongsri Ruangdaj 
Published: May 2021

Abstract
Experimental sintered Fe-Mo-Mn-Si-C composites were prepared from 3 different pre-alloyed Fe-Mo-Mn powders, namely Fe-0.50Mo-0.15Mn, Fe-0.85Mo-0.15Mn and Fe-1.50Mo-0.15Mn, mixed with fixed 4 wt.% silicon carbide powder. Sintered Fe-SiC composite was also prepared, as a reference material, from pure Fe powder mixed with fixed 4 wt.% silicon carbide powder. All specimens were processed by using the ‘press and sinter’ method. Sintering was performed in a vacuum furnace at 1250ºC for 45 minutes and slow cooling in the furnace. The microstructures of most sintered alloys showed a common feature consisting of a black particle enveloped with ferrite and pearlite. Sintered composites produced from high-molybdenum powders showed different matrices, in which some pearlite regions were replaced by BF/M- A structures. The Tensile and hardness test showed that the sintered alloys exhibited an increase of tensile strength, yield strength, and hardness with increasing molybdenum content. The pearlite + BF/M-A fractions of sintered composites played important roles in material strengthening. In the sintered composites produced from high-molybdenum powders, the carbide-free BF/M-A structure showed a promising strengthening effect.
Comparative study on the wood-based PLA fabricated by compression molding and additive manufacturing
Authors: Chansoda Kanjanaphorn , Suvanjumrat Chakrit , Chookaew Watcharapong 
Published: May 2021

Abstract
Additive manufacturing namely 3-Dimensional (3D) printing and it’s feeding materials are increasingly used for producing customized products. Fused Deposition Modelling (FDM) in conventional 3D printers is a cost-effective solution. This is due to the low cost of the machine and various size selections. Although the machine cost is reasonable, the filament material is a higher cost. In general, the current filament is priced about 4 times more than granulated plastic. Moreover, the special filament containing wood powder shows a high cost of approximately 20 times that of pellets. This work proposes a comparative study of the components obtained from different processes. Compression molding and no-mold techniques were used. A previous design, nozzle from extrusion concept, was also used for fabricating the specimens. PLA and wood-based PLA were carried out to produce the testing samples. The results showed that parts obtained from the compressive mold showed low tensile strength. It was indicated that the residue voids were significantly affected by its strength. Taking into account the 3D printed parts, the articles from the designed extruder present a higher strength than the results derived from the conventional 3D printer and compression machine. On the other side, it was found that the moving direction of the nozzle (raster angle) affected directly the maximum tensile strength. Furthermore, the neat PLA had higher stress than the wood-composite materials used for all fabrication methods. However, in the case of using an extrusion device, it represented the enhancing of mechanical strength, which was caused by the homogeneous texture of polymers melting in a hot barrel. In terms of fabrication cost, the molding technique showed the highest cost even though the feeding material has the lowest cost. A similar cost was found for providing parts from the conventional printer and our design nozzle. However, a pellet-based extruder would be printed the sample filled 15%wt, conventional but the 3D printer is unavailable. Furthermore, recycled materials or waste of 3D printed parts can be utilized by using a conceptual extruder.
Influences of cooling rate and carbon content microstructure and mechanical properties of sintered Fe-1.5Mo-xC alloys
Authors: Wanalerkngam Arisara , Boonmee Sarum , Srichumpong Thapanee , Morakotjinda Monnapas , Tosangthum Nattaya , Tongsri Ruangdaj 
Published: May 2021

Abstract
Sintered Fe-1.50Mo-xC alloys were produced by the sintering of powder compacts made from mixtures of pre-alloyed Fe-1.5Mo powder and varied carbon amounts (0.30-1.20 wt.% with 0.15 increment) followed by slow and fast cooling rates. The slowly cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.45 wt.%) showed microstructures consisting of polygonal ferrite grains and eutectoid transformation products. When carbon contents were higher than 0.45 wt.%, eutectoid transformation products were dominant. The fast-cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.75 wt.%) showed microstructures consisting of upper bainite. When carbon contents were higher than 0.75 wt.%, upper bainite and inverse bainite were dominant. Tensile strength and hardness values of sintered Fe-1.50Mo-xC alloys increased with increasing carbon content. In addition, fast cooling further enhanced mechanical properties of the sintered alloys. It was found that values of ultimate tensile strength (UTM) and hardness on slow and fast cooling rates were 385-565 MPa, 564-743 MPa, 43-78 HRB and 60-82 HRB, respectively.
Evaluation of wall functions for RANS turbulence models by unsteady lid-driven cavity flow
Authors: Suvanjumrat Chakrit , Loksupapaiboon Kittipos 
Published: May 2021

Abstract
Turbulence models do not perform well near walls because the Reynolds number in this interesting area is low. The wall functions and the advantage method can be efficiently used to model fluid flow at the near wall region. The Reynolds averaged Navier-Stokes turbulence models which had the developed wall functions in Open FOAM, the open source CFD software, were evaluated by the turbulent flow. The 3-D lid-driven cavity flow at the turbulence Reynolds number of 10,000 with various spanwise aspect ratio had been referred to validate these turbulence models. The comparison shown that the realizable k-ɛ turbulence model with the standard k and ɛ wall functions of OpenFOAM was the most powerful model to represent the velocity profile of water flow in the 3-D lid-driven cavities.
Crash analysis of sandwich composite electric microbus
Authors: Jongpradist P. , Limpanawisut S. , Siritana A. , Saardying P. , Saingam N. , Tangthamsathit P. , Chanpaibool P. 
Published: May 2021

Abstract
Sandwich composite is ideal for lightweight monocoque structure owing to not only its superiority in strength-to-weight ratio and specific flexural properties but also its manufacturability to any desired complex shape. In this work, an optimum lightweight design of monocoque composite sandwich-structure microbus subjected to bending and torsion stiffness criteria and natural frequency constraints is further investigated under crash conditions through finite element analysis. A composite sandwich panel made of 5.4-mm woven glass fabric-epoxy face sheets and 50-mm rigid polyurethane foam core is tested under low-velocity impact with a hemisphere headed impactor following ASTM D7136 to characterize the failure characteristics. An enhanced composite damage material model so-called MAT54 in LS-DYNA with damage progression in each lamina utilizing strength-based Chang-Chang criteria is implemented with various formulations to validate and compare for their efficiency and accuracy under impact test. The reduced-integration Balytschko-Tsay shell element with 5 through-thickness integration points is applied to the monocoque composite microbus model. The structural crashworthiness under the frontal crash of the bus at 20, 40 and 50 km/h to a rigid wall barrier is examined. The front structure absorbs the most frontal impact energy up to 60% and shows severe damage when the crash velocity is 40 km/h or higher. For the bus impact velocity of 50 km/h, the maximum deformation of the bus front is 809 mm resulting in the intrusion of the structure into the specified driver survival space. Design improvement of the sandwich structure should be further explored to enhance its energy absorption and safety of the bus under crash events.
Numerical simulations of cancer treatment prediction: modeling the influence of immunity
Authors: Ezaki Yuka , Nagayama Katsuya , Miura Ichiro 
Published: May 2021

Abstract
Malignant tumors, also called cancer or malignant neoplasms, are life-threatening tumors that invade the borders of other tissues or spread to other parts of the body and grow in various locations [1]. Recent evidence suggests that cancer cells generated by genetic mutations are eliminated by immune cells. Immune cells are immune cells that recognize and attack foreign substances, pathogens, and cancers in the body. A decline in immunity due to ageing or nutritional deficiencies, or due to immunosuppression is associated with increased risk of cancer cells [2]. Immunotherapy is a treatment method that activates the body’s innate immune function to eliminate cancer cells. This study, therefore, set out to assess the effect of immunotherapy using numerical simulations. Parameters, such as the conditions of cancer cell death with immune cells, cell division, and angiogenesis, were theoretically set and introduced into the model.
Emulation of battery discharge behaviour using programmable power supply based on LabVIEW
Authors: Tanruean N. , Charoenphonphanich C. , Yenwichai T. , Masomtob M. 
Published: May 2021

Abstract
This paper presents a battery simulator based on the actual electrical behaviour of the battery cells using power supply controlled by Laboratory Virtual Instrument Engineering Workbench (LabVIEW). Firstly, the behaviours of the battery are tested under experimental conditions including constant temperatures at 25C˚ and two different current loads at 0.5C and 1C. Secondly, the battery behaviours are analysed and applied in LabVIEW. The algorithms which are low pass filter, PID and others are implemented in LabVIEW to reduce standard deviations and errors. The current study found that the constant load at 0.5C and 1C, which controlled by the electronic load via LabVIEW, can emulate the battery voltage and the error relative is below 5 %. Further work is required to establish the optimization of the parameters in the battery management system (BMS) since a battery simulator uses power sources before the use of the battery management system (BMS) with a real battery.
Enhanced thermal performance in a square-duct heat exchanger with inclined square-rings
Authors: Khanoknaiyakarn Chitakorn , Promthaisong Pitak , Hoonpong Panuwat , Promvonge Pongjet , Skullong Sompol 
Published: May 2021

Abstract
An experimental work has been conducted to explore thermal and turbulent flow friction characteristics in a uniform heat-fluxed square-duct contained with inclined square-rings (SR). Experiments were performed for different geometric parameters of the SR elements, focused on their detailed effects on the optimal thermal performance. Influences of five different ring-to-duct height or blockage ratios (BR=b/H= 0.1, 0.15, 0.2, 0.25 and 0.3) on friction factor (f), Nusselt number (Nu), and thermal enhancement factor (TEF) in the square duct are investigated for Reynolds number (Re) from 4210 to 25,800. The inclination angle (a) and the ratio of axial pitch length of rings to the height of duct (called pitch ratio, PR=P/H) were kept constant at 60° and 3.0, respectively. The experimental result has shown that the SR insert gives greater heat transfer and friction loss than the plain duct acting alone. Increasing the blockage ratio (BR) results in the drastic enhancement in Nu and f values. The inserted duct with BR = 0.25 has the maximum TEF around 1.57. Comparing thermal performance at identical operating conditions, the SR insert at BR = 0.15 gives around 1.1 %, 2.3 %, 3.2 and 4.5 % higher than the one at BR = 0.2, 0.25, 0.3 and 0.1, respectively.