bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of epitaxial strain on the electronic and magnetic structure of La0.7Sr0.3MnO3/LaCoO3 bilayers
Authors: Das S. , Ghosh S. , Tanguturi R. G. , Medwal R. , Gupta S. , Dokala R. K. , Rawat R. S. , Das S. , Thota S.
Published: December 2021

Realizing atomically flat interfaces between the ultrathin perovskite oxides is a challenging task, which usually possess different chemical environments, depending on the terminating lattice planes. Hence, tuning the interfaces across the heterostructures for desired electrical and magnetic properties is a powerful approach in oxide electronics. Focusing on these aspects, in the present work we employ a novel strategy of engineering the interfaces through the layer stacking sequence and degree of strain to probe the changes occurring in the local atomic environment at the interfaces, magnetic behaviour, and electronic properties of ferromagnetic bilayers La0.7Sr0.3MnO3 (LSMO)/LaCoO3 (LCO) grown by the pulsed laser deposition technique. The biaxial tensile strain experienced by these layers drives the ferromagnetic (FM) ordering temperatures to lower values as compared to their bulk counterparts. Interestingly, the bilayer sequence LCO (15 nm)/LSMO (5 nm) (BL2) exhibits large magnetocrystalline anisotropy (Ku ≈ 4.7 × 104 erg/cc) and weak anti-FM coupling across the interface of the two FM constituents, resulting in a partial compensation in the magnetic moment of the system within a specific temperature window (ΔT = 184 − 82 K). However, for T ≤ 82 K, the FM superexchange interaction between the trivalent Co high-spin and low-spin states dominates the overall magnetic ordering in BL2. The magnetodynamic features probed by the frequency dependent FM resonance (FMR) on this system yield the gyromagnetic ratio (γ/2π ∼ 29.22 GHz/T), demagnetization fields (4πMeff ∼ 3770 Oe), and effective damping constant (αeff ∼ 0.0143) for the BL2 configuration. Moreover, the strength of the nearest-neighbor exchange interaction Jeff in the BL2 configuration exhibits linear falloff with the increasing LCO layer thickness (2 nm ≤tLCO≤ 18 nm). This scenario is also consistent with the variation of the effective number of spins available per unit volume [10 cm−3 ≤ NV(×1022) ≤ 2 cm−3] with increasing tLCO. As tLCO approaches negligibly small values (<2 nm), the magnitude of Jeff/kB reaches its maximum ∼5.47 K (for LCO) and 21.93 K (for LSMO), which is in good agreement with Jeff/kB ∼ 5 ± 2 K (20 ± 2 K) for highly epitaxial LCO (LSMO) single layers. These results demonstrate that the layer sequence control of magnetic coupling across the interfaces opens a constructive approach for exploring the novel electronic devices.
Temperature dependence of cathodoluminescence emission in irradiated Si-doped β-Ga2O3
Authors: Modak Sushrut , Chernyak Leonid , Schulte Alfons , Xian Minghan , Ren Fan , Pearton Stephen J. , Ruzin Arie , Kosolobov Sergey S. , Drachev Vladimir P.
Published: December 2021

Temperature dependent continuous and time-resolved cathodoluminescence measurements were employed to understand the luminescence from Si-doped β-Ga2O3 prior to irradiation and after 10 MeV proton and 18 MeV alpha-particle irradiation. The shape and location of the luminescence components [ultraviolet luminescence (UVL′) at 3.63 eV, UVL at 3.3 eV, and blue-luminescence at 2.96 eV] obtained from Gaussian decomposition did not change in either width or peak location, indicating that new radiation-induced trap-levels were non-radiative in nature between the 4.5 and 310 K temperature range. Activation energies, associated with thermal quenching of UVL′ and UVL bands, show temperature dependence, suggesting ionization of shallow Si-donors and a thermally activated non-radiative process.
Electron swarm parameters and dielectric strength of C5F10O and its mixtures with CO2 and dry air
Authors: Hao Mai , Zhang Boya , Li Xingwen , Xiong Jiayu
Published: December 2021

Perfluoroketone C5F10O is considered as a potential SF6 alternative. The global warming potential of C5F10O is extremely low and even close to that of air. We investigated the electrical insulation properties of the C5F10O by pulsed Townsend experiment. The rate coefficients of ionization, attachment, and effective ionization, as well as the electron drift velocity and the longitudinal electron diffusion coefficient in pure C5F10O were obtained. We conclude that the density-reduced critical electric field of pure C5F10O is (768 ± 5)Td and ion kinetics are not exist or negligible in C5F10O. Furthermore, the swarm parameters of C5F10O/CO2 and C5F10O/Air mixtures with C5F10O percentage up to 30% were measured in a wide E/N-range. C5F10O has good synergism with both CO2 and dry air and air behaves better. The synergistic effect coefficients were also calculated. To have the same (E/N)crit as pure SF6, the mixing ratio of C5F10O should be 30% in the mixture with CO2 and 26% in the mixture with dry air. The obtained electron swarm parameters in this paper provide a supplement for the fundamental data set of these novel gases, and also lay the foundation for fluid model simulations of gas discharge.
Evaluation of grain boundary energy, structure and stiffness from phase field crystal simulations
Authors: Blixt Kevin Hult , Hallberg Håkan
Published: December 2021

A two-mode phase field crystal (PFC) model is employed to investigate the equilibrium configurations of a range of grain boundaries in fcc-structured materials. A total of 80 different symmetrical tilt grain boundaries are evaluated by PFC simulations in 3D and the results are shown to agree well with data taken from the literature, both regarding the variation of grain boundary energy and also in terms of the resulting grain boundary structures. This verification complements existing PFC studies which are almost exclusively focused either on grain boundaries found in 2D systems or in bcc lattices in 3D. The present work facilitates application of PFC in the analysis of grain boundary mechanics in an extended range of materials, in particular such mechanics that take place at extended time scales not tractable for molecular dynamics (MD) simulations. In addition to the verification of predicted grain boundary energies and structures, wavelet transforms of the density field are used in the present work to obtain phase fields from which it is possible to identify grain boundary fluctuations that provide the means to evaluate grain boundary stiffness based on the capillarity fluctuation method. It is discussed how PFC provides benefits compared to alternative methods, such as MD simulations, for this type of investigations.
Smallest remnants of early matter domination
Authors: Barenboim Gabriela , Blinov Nikita , Stebbins Albert
Published: December 2021

The evolution of the universe prior to Big Bang Nucleosynthesis could have gone through a phase of early matter domination which enhanced the growth of small-scale dark matter structure. If this period was long enough, self-gravitating objects formed prior to reheating. We study the evolution of these dense early halos through reheating. At the end of early matter domination, the early halos undergo rapid expansion and eventually eject their matter. We find that this process washes out structure on scales much larger than naively expected from the size of the original halos. We compute the density profiles of the early halo remnants and use them to construct late-time power spectra that include these non-linear effects.
We evolve the resulting power spectrum to estimate the properties of microhalos that would form after matter-radiation equality.
Surprisingly, cosmologies with a short period of early matter domination lead to an earlier onset of microhalo formation compared to those with a long period. In either case, dark matter structure formation begins much earlier than in the standard cosmology, with most dark matter bound in microhalos in the late universe.
Ångström-Prescott Models of Solar radiation over Earth surface
Authors: Bautista-Rodríguez Gloria MarinaGloria Marina , Chacón-Cardona César Alexander
Published: December 2021

The current energy demand increases every day and the deficit of electricity generation in Colombia due to technical aspects such as the lack of generation infrastructure, cost overruns in the construction projects of new plants and environmental variability as a consequence of climate change, entail a high risk of energy rationing; for this reason some of the users, whether industrial or residential, have decided to seek multiple alternatives to reduce the costs of their billing in interconnected areas and even supply their energy needs.

Among these alternatives is found solar energy in its thermal and photovoltaic use, a resource that must be characterized in order to determine the technical and budgetary aspects involved in the implementation of profitable energy generation projects. This article seeks to provide technical tools for the design and implementation of generation projects based on solar energy, providing physical-mathematical approach based in the classical Angström-Prescott model that allow engineers and researchers to model the global solar radiation on the Earth’s surface in order to maximize the use of this resource in a specific geographical location.

Although there are different ways to characterize the solar resource on the earth’s surface, this paper presents a review study focused on the most important global solar radiation estimation models present in the literature.
Mechanical Design and Improvement of Computer Automatic Production Line
Authors: Jiang Haixiang , Tang Yanhua , Jiang Quanxin
Published: December 2021

The mechanical design amelioration of automatic production line can intelligently adjust the production rhythm of the production line on demand, control the rhythm of production scheduling according to the production process requirements, and establish a modular design mode, so it has important research value. Based on this, this paper first analyses the mechanical design principle of the automatic production line, then studies the computer control system of the automatic production line, and finally gives the amelioration measures of the mechanical design of the automatic production line.
Concrete Management Monitoring System Based on Particle Swarm Algorithm
Authors: Pan Dongying
Published: December 2021

With the rapid development of the national construction infrastructure industry, concrete structures often have various problems such as cracks in the early and later operations. The further development of these problems may endanger the structural safety of the entire building. The particle swarm algorithm is simple to operate, less parameter settings, easy to implement, etc., which can solve the problem of concrete monitoring. Based on this, the purpose of this article is to study the concrete management monitoring system based on particle swarm optimization. This article first summarizes the basic theory of particle swarm algorithm, and then extends its core algorithm technology. Analyze the existing problems and deficiencies in the current concrete structures in our country. And use particle swarm algorithm to research and analyze the concrete management monitoring system. This paper systematically describes the outline design and detailed design of the concrete management monitoring system based on particle swarm optimization. And by comparative method, field survey method and other research forms to carry out experimental research on the main body of this article. Research shows that the maximum absolute error of the crack width measured by the particle swarm optimization-based concrete management monitoring system W2 and the actual crack width W1 measured by the crack width comparison ruler is 0.232mm, which is less than 0.3mm, and the maximum relative error is 4.59%, to meet the system design requirements, which proves the rationality and effectiveness of the system.
Feature Extraction and Analysis of Microseismic Signal Based on Convolutional Neural Network
Authors: Zhang Hui , Zhai Hao , Zhang Ke , Wang Lujun , Zhao Xing , Wei Jianmin
Published: December 2021

Seismic detection technology has been widely used in safety detection of engineering construction abroad. Although it has just started in the field of engineering in our country, its role is becoming more and more important. Through computer technology, micro-seismic detection can provide accurate data for the construction safety detection of large-scale projects, which has important practical significance for the rapid and effective identification of micro-seismic signals. Based on this, the purpose of this article is to study the feature extraction and classification of microseismic signals based on neural games. This article first summarizes the development status of microseismic monitoring technology. Using traditional convolutional neural networks for analysis, a multi-scale feature fusion network is proposed on the basis of convolutional neural networks and big data, the multi-scale feature fusion network is used to research and analyze microseismic feature extraction and classification. This article systematically explains The principle of microseismic signal acquisition and the construction of multi-scale feature fusion network. And use big data, comparative analysis method, observation method and other research methods to study the theme of this article. Experimental research shows that the db7 wavelet base has little effect on the Megatron signal.
Automatic Electromechanical Control System Based on PLC Technology
Authors: Xi Yan , Xing Qin
Published: December 2021

With the continuous progress of science and technology, China is transforming into the field of industrial automation, striving to contribute to the liberation of labor force and the realization of assembly line industrial automation. The operation of the traditional automatic electromechanical control system(AECS) still needs a lot of manual operation, which is difficult to realize the development of all automation of electromechanical control. The new AECS proposed at present is to realize the automation, intelligent and remote control of electromechanical control system, and truly take the control system as the center for electromechanical control production.Therefore, this paper puts forward the design and application of AECS based on PLC technology. Through research, this paper expounds the AECS based on PLC technology and its application. PLC technology can realize automation and integrated control in system control, compact structure, and can accommodate the conversion of many digital signals to realize its control function of the system, study the software design of AECS, mainly design the input interface and output interface. In order to understand the application and performance of PLC technology in automatic electromechanical system, this paper compares and analyzes the fuzzy PID control error of PLC technology and the performance of AECS based on PLC technology with traditional AECS. The experimental results show that in the comparative analysis of simulation experiments between the performance of AECS based on PLC technology and traditional AECS, the proportion coefficient of traditional AECS is 1.63, the integral time constant is -1.06, and the differential time constant is 0.29, while the proportion coefficient of AECS based on PLC technology is 0.56, the integral time constant is 0.37 and the differential time constant is 1.18. The deviation of AECS based on PLC technology is smaller than that of traditional automatic electromechanical control, and the static error is also smaller, but its response speed is faster and its performance is better.
Short-term Load Forecasting System for Power System Based on Big Data
Authors: Donghui Yang
Published: December 2021

Short-term load forecasting of power system is an important task of power distribution system. Accurate short-term load forecasting provides the best configuration for grid power generation and distribution, maximizing energy saving and ensuring stable operation. This paper aims to study the design of short-term load forecasting system of power system based on big data. On the basis of analyzing power system load forecasting algorithms, classification of load forecasting, characteristics of load forecasting and system design principles, each module of the system is designed in detail, and finally tested the performance of the system. The test results show that the system has no adverse reactions in the use of a large number of users and repeated operation for a long time. In the case of large throughput, the system has a satisfactory response time and relatively reliable system stability.
Dutomatic Detection Technology of Intelligent Meter Based On Machine Vision
Authors: Zhang Zhilong , Yang Lin , Su Hong , Wang Weiguang , Jiang Tao
Published: December 2021

In view of the low detection rate of LCD appearance quality of smart meters in the current low contrast environment, this study puts forward the research of intelligent meters automation based on machine vision, and puts forward corresponding solutions and strategies according to this problem. Firstly, the image of the LCD area of the smart meter is extracted. On this basis, the image of the LCD screen of the ammeter is enhanced by the method of wavelet transform. Then, the LCD area of the smart meter is accurately divided. Then the morphological gradient is used to reconstruct the character information, and finally realize the automatic detection of intelligent electricity. The experimental results show that the method proposed in this paper has certain feasibility and effectiveness, improves the accuracy of appearance detection of smart meter, and has certain practical significance in power industry.
Intelligent of Electric Vehicle Heat Pump Air Conditioning Control System
Authors: Zhao Lianghong , Hou Wensheng , He Qinbo
Published: December 2021

Traditional fuel vehicles consume a lot of fuel and cause serious environmental pollution. At present, when environmental protection is being paid more and more attention, Electric vehicles have received extensive attention from countries all over the world for their advantages in energy safety, environmental protection and long-term development. Electric vehicles have received extensive attention from countries all over the world for their advantages in energy safety, environmental protection and long-term development. With the rapid development of electric vehicles, as the main energy consumer, following the electrical system, the air-conditioning system has become an important factor restricting the power, economy and durability of electric buses. At the same time, compared with the current electric heating PTC method commonly used in electric vehicles, heat pump air conditioners can increase the working range of electric vehicles. Therefore, the application of large-scale energy-saving systems, high-efficiency energy-saving systems, and electric vehicle air-conditioning systems is developed, it is of great significance to the promotion of electric vehicles. This article aims to intelligently study the control system of the electric vehicle air-conditioning heat pump.
Breakdown Characteristics of Long Air Gap at Different Frequency Based on Series Resonance
Authors: Hu Zhengyong , Xu Peng , Tan Wenlong , Gao Kai , Cui Lv
Published: December 2021

In today’s rapid economic development, with the development of science and technology, higher requirements have been put forward in the economic operation of the system. This requires various departments to make more reasonable use of existing energy and equipment, and to ensure quality. Meet all aspects of supply with more energy-saving and more economical operation methods. Therefore, more and more attention has been paid to the research on the method of predicting the breakdown voltage of the air gap. Although domestic and foreign scholars have used power frequency test transformers to carry out a large number of long air gap experimental researches, the research on the breakdown voltage of long air gaps based on the principle of vector machines is still blank. In this paper, a vector machine test device is used to study the breakdown discharge characteristics of a long air gap at two frequencies of 229Hz and 68Hz. Comparing the test phenomena at different frequencies, it is found that the initial discharge voltage of the streamer corona is lower when the frequency is 229Hz, and the discharge phenomenon before breakdown is more intense, and the quality factor will be significantly reduced due to the violent discharge. At the same time, under the same test conditions, the breakdown voltage at 229Hz is lower than that at 68Hz, and as the air gap increases, the difference between the two is greater. The experimental results show that the breakdown voltage of the long air gap based on the vector machine is different when the frequency is different, and the safety distance of the field withstand voltage test should be evaluated according to the experimental data under the vector machine condition to ensure the safety of the test.
Research of the influence of bias voltage on the structure and residual stress in Ta/W coatings applied on a copper substrate by inverted magnetron
Authors: Lozovan A A , Lenkovets A S , Ivanov N A , Sukhova T S
Published: December 2021

This paper presents the results of studying the effect of the bias voltage on a copper tube substrate on the texture and residual stresses in 4-layer Ta/W/Ta/W coatings deposited with an inverted magnetron. It is shown that, in contrast to monolayer coatings of Ta and W, in which residual stresses exceeding 2 GPa are formed on the substrate at high voltages on the substrate, stress relaxations occur in the 4-layer coating in alternating layers differing in LTEC values and in the outer W-layer of stress practically absent.
General principles for describing electronic and proton multiple scattering processes in solids
Authors: Afanas’ev V P , Lobanova L G , Selyakov D N , Semenov-Shefov M A
Published: December 2021

Analytical solution for the reflected light ions Pass Length Distribution Function (PLDF) equation is obtained. Reflected ions energy spectra calculated on the basis of the developed method shows satisfactory agreement with experimental data. The effectiveness of the developed methodology in the procedure for verifying the stopping power value is indicated.
The applying of layer-by-layer laser remelting in the technology of laser metal deposition
Authors: Zavalov Y N , Dubrov A V
Published: December 2021

Layer-by-layer laser remelting (LRM) was used in the technology of laser metal deposition in order to reduce the porosity of the layer in the case of single-layer and multi-layercoatings. The layer porosity is shown to decreases with LRM at a rate 5 times higher than the rate of metal deposition. The dependence of the porosity estimated using the method of the hydrostatic weighing on the rate of laser remelting is obtained.
Evaluation of tribotechnical properties of modified surfaces after plasma electrolytic treatment
Authors: Mukhacheva T L , Kalinina T M , Kusmanov S A
Published: December 2021

The article considers the study of the effect of plasma electrolytic processing on the tribotechnical characteristics of medium-carbon steel. Friction tests were carried out in dry friction mode. Electron microscope and profilometer were used to study the friction tracks. For a comprehensive assessment of the quality of the modified surface layer, the Kragelsky-Kombalov complex parameter was calculated. It was found that plasma electrolytic treatment leads to a decrease in the coefficient of friction and weight wear in comparison with hardened and untreated steel. It has been determined that the mechanism of wear of samples after plasma electrolytic treatment is fatigue wear at boundary friction and plastic contact.
Temperature distribution in a cylindrical lengthy workpiece under plasma electrolytic heating
Authors: Shadrin S Yu , Zhirov A V , Mukhacheva T L
Published: December 2021

The article focuses on developing a model of a stationary temperature field inside a semi-infinite cylindrical sample partly immersed in electrolyte. Temperature calculation is carried out by solving a heat transfer equation separately for the immersed and protruding parts of the sample. The heat flux is set on the outer area boundaries; meanwhile heat flux density for the immersed part is linearly dependent on the vertical coordinate. Within the framework of the model, vertical and radial temperature gradients are worked out both in protruding and immersed parts of the anode. It has been established that the vertical coordinate of the sign reversal point of the heat flux density in the immersed part depends on heat exchange conditions in the protruding part.
Beneficiation of cassiterite from primary tin ores using gravity and magnetic separation
Authors: Rodliyah I , Wijayanti R , Hidayat K N , Dianawati E A , Sudrajat A , Firmansyah D
Published: December 2021

Alluvial tin ore deposit of PT. Timah is predicted to be depleted in the next 5 to 10 years. Finding a new source of tin ore is important for the company’s sustainability. PT. Timah has been exploring for primary tin ore. Tin (Sn) content in primary tin ore ranges from 0.2 – 1.0%. The Sn particles liberated in the cassiterite mineral are above 50% so they can be processed by the physical separation method. This research aims to observe the beneficiation of cassiterite from primary tin ore (oxide and skarn samples) using gravity and magnetic separation. The cassiterite concentrate produced from the beneficiation process is expected to be used as feed for the smelting process. Beneficiation results of primary tin ore (oxide and skarn samples) showed that cassiterite (SnO2) content were 15.09% and 40.03%, respectively and the recovery was 42.9% and 11.87%, respectively. The cassiterite concentrate produced from the beneficiation process cannot be used to feed the smelting process.
Batusatam physical and chemical properties review: A Billitonite tektite in Southeastern Belitung Island, Indonesia
Authors: Harbowo D G , Afdareva M , Inggrid V , Sumardi S
Published: December 2021

Batusatam considers as Billitonite, a rare Australian strewnfield tektite. Regrettably, the scientific information of this object slightly, especially about the origin, the process of formation, and its uniqueness in the earth’s geological history. This paper reviewed the physical and chemical properties of unearthing Batusatam in Southeastern Belitung Island, Indonesia. Physical properties are examing based on object shape, surface texture pattern, dimensions, volume, mass, density, and hardness. We also analyzed major and minor elements using portable X-ray fluorescence (XRF) and compared them with another Australian tektite. Rod and tear-drop-shape, the unique shapes of Batusatam, were discovered. It had a higher FexOy, CaO, MnO proportion. Also, Sn (tin) is present significantly compared to other tektites. This significant uniqueness of Billitonite could clarify its origin, formation process, and role as a geoheritage.
The sequential REE (Rare Earth Elements) extraction of weathered crusts of granitoids from Sibolga, Indonesia
Authors: Setiawan I
Published: December 2021

Indonesia needs a proven technology for REE extraction to build a national REE industry. Monazite that has been recovered from placer deposits at Bangka-Belitung areas is the most potential REE source. In the future, ion adsorption type will be another potential source of REE deposits. This paper describes the sequential REE extraction of the weathered crusts of granitoids from Sibolga using sequential extraction ICP-MS analysis is applied to determine bulk samples mineralogical compositions and REE content. The total REE (∑REE) content of weathered crusts of granitoids from Sibuluhan Sihaporas A ranges from 265 to 479 ppm, while the amount of ∑REE leached by sequential extraction range from 151 to 263 ppm, and the percentage of adsorbed ∑REE ranges from 55 to 74%. In comparison, Sibuluhan Sihaporas B ranges from 302 to 634 ppm, 82 to 198 ppm, and 28 to 44%, respectively. ∑REE content of weathered granitoids crusts from Sarudik ranges from 135 to 219 ppm, while that SREE leached by sequential extraction range from 21 to 82 ppm, and percentage of adsorbed ∑REE range from 11 to 50 %, while that Sibolga Julu ranges from 191 to 304 ppm, 111 to 138 ppm, and 27 to 44%.
Valuation slagging factors and greenhouse gases emissions of paper mill reject and coal
Authors: Setiawan Y , Syamsudin
Published: December 2021

There are quite a lot of paper mill rejects (PMR) as a by-product of paper mills and have not been utilized, currently. The purpose of this study is to evaluate the characteristics of paper mill reject (PMR) to coal and natural biomass and estimate the greenhouse (GHG) emissions of PMR and coal. Coal and PMR taken from five paper mills were analyzed for the content of moisture, proximate parameter (ash, volatile matter, fixed carbon), sulfur (S), gross calorific value (GCV), ash mineral and ash fusion temperature (AFT). The slagging factors of materials were calculated and evaluated. The resulting greenhouse gasses (GHG) emissions was also estimated. The results show that with the high calorific value, low ash and sulfur content of PMR, it has the potential to be used as a coal mixture for boiler fuel. It is very beneficial for the environment due to the low SO2 emissions. PMR has the characteristics of a low slagging index (SI), high fouling index (FI) and Slag Viscosity Index (SVI) which is almost similar with biomass, empty fruit bunches (EFB) and rice husk. The use of PMR as a coal mixture in paper mills in the amount of 10,285 ton/year can reduce greenhouse gases of 63.5 tons CO2-equivalent/year.
Preliminary modeling for module estimation on the underground coal gasification project
Authors: Zulfahmi  , Huda M , Sirait B , Maulana A , Lubis A
Published: December 2021

Designing the module is one of the initial works of the underground coal gasification (UCG) feasibility study, consisting of the coal area to be gasified as panels and the coal to be left as pillars. Three models have been designed with each panel dimension 380 m in length, 150 m in width and 18 m thick. The finite element method is used in the study and the 2D and 3D geotechnical simulations have been carried out with variations of the pillars. As a result of 2D modeling, the critical strength reduction factor (SRF) is 0.25 with the highest deformation on the surface is 0.04 m (SMA-C) and 0.03 (SM-D) if the pillar is 50 m width. If SRF is increased to 0.37, the deformation on the surface is 0.36 (SMA-C) and is 13.5 (SM-D), respectively. From the 3D modeling results, if it is assumed that the velocity of the UCG reactor hole rate is 0.24 m/day until it reaches the final target length of the reactor hole 380 m, the maximum deformation of the soil surface at the SMA-C and SM-D locations is 0.074 m and 0.096 m, respectively. Determination of the module is important in the feasibility study and evaluation of the UCG site.
Enhanced processing of magnetic data for delineating lithological boundary and geological structure of the epithermal gold mineralization control system - A case study: Cibaliung Area, Indonesia
Authors: Eko Junian Wahyu , Yadi Paembonan Andri , Hutami Harnanti Y , Arief Wicaksono Muhammad
Published: December 2021

Cibaliung is an area that is traversed by the Au-Ag-Cu mineralization pathway from low to intermediate sulfide epithermal system. The implemented techniques for delineating probable gold deposits by the lithology contact and structures that control epithermal gold mineralization systems in the area include first vertical derivative (FHD), vertical derivative (VD), second vertical derivative (SVD), analytic signal (SA), and tilt angle (TA). The results shows that high continuity of anomaly contrast in the direction of Northwest (NW), North-Northwest (NNW), and North-Northeast (NNE) is presumed to be the target geological structure of the study area. Furthermore, the contrast value of magnetic anomaly represents the lithology contact lies in the direction of the West and the East of the area.
Impacts of increasing the airflow rate on load-haul-dump heat spread at an underground mine
Authors: Kaiyandra D R , Yulianti R , Hartami P N
Published: December 2021

In the mining process, mining companies use various mining equipment to extract valuable materials. One of them is a load-haul-dump (LHD) machine. Although this equipment is very helpful in the production process, it also has drawbacks. This equipment emits heat that can affect air temperature in the mine tunnel and cause a decrease in the comfort of mineworkers, which then impacts the mine productivity. One of the methods that can be carried out to overcome this problem is to increase the amount of airflow by changing the ventilation network. Therefore, this study aims to determine the impacts of increasing airflow on the heat spread of the operated LHD machines. The results of this study are to provide a method for reduced temperature visually and can be used as a recommendation for temperature reduction in the future. To examine the heat spreading, the researchers applied a tunnel model made using CFD software that is ANSYS Fluent and use VentSim software to simulate the network changes. The results indicated that the increase of the airflow rate could reduce the temperature on the work front when the LHD machines are operating and can affect the heat spread.
Assessing slope failure in coal mining using kinematic analysis
Authors: Sirait Bagaraja , Salinita Silti , Zulfahmi  , Pujianto Eko
Published: December 2021

Slope stability analysis is one of the important issues in open-pit mining. It is directly influences mining operation and cost. It also becomes a primary need to prevent slope failures that disturbing production activity. Failures in slope are controlled by factors such as slope dimension, geological structures, physical and mechanical properties of slope material, and the external forces acting on the slope. This paper presents the study results on the prediction of slope stability analysis by using kinematic analysis. The study was conducted to predict the potential slope failures that could occur at the selected mine site. The site was chosen on one of the locations of open pit coal mining PT. X in East Kalimantan. Some observation points are determined to show types of failure that can occur, such as plane and wedge failure. The results show that the potential failure of the planar type occurs in 8 locations while the wedge failure occurs in 7 locations. The potential failure occur in 5 observation points, i.e: Pit-1/OP-1, Pit-2/OP-1, Pit-3/OP-1, Pit-5/OP-1, Pit-5/OP-3. Other points are in stable condition because the plane’s direction is opposite the slope direction.
1-Dimensional numerical modelling of unsaturated water flow and oxygen diffusion in overburden material column using hydrus 1-D
Authors: Jarwinda  , Badhurahman A , Kusuma G J , Gautama R S
Published: December 2021

Coal mining activities, especially overburden material dumping can cause a negative impact into the environment, i.e., acid mine drainage, Acid mine drainage is characterized as low pH water with high sulphate and metal content produced from sulphidic-bearing overburden material with oxygen and water. In unsaturated condition, both of gaseous and water phases exist, acid mine drainage is generated. This study aims to characterize and model the water content in unsaturated condition and diffusion of oxygen of overburden material using the Hydrus 1-D software in a laboratory-scaled column. Laboratory-scaled column is initially filled with 75-cm height of dry overburden material and subjected into 5-cm constant head water level at the top of the column with free-flow condition at the bottom of column. The modelling result shows the water content of overburden material varies within depth and time elapsed and is saturated between 32400 minutes and 36000 minutes after initial wetting. Diffusivity of oxygen is linearly correlated with the water content of the overburden material at any given time and depth that varies between 1.34 × 10−7 m2/s and 8.80 × 10−12 m2/s. Water content and diffusivity of oxygen is expected to affect the generation of acid mine drainage in the overburden material.
The Fe (II) and Mn (II) adsorption in acid mine drainage using various granular sizes of activated carbon and temperatures
Authors: Suliestyah  , Novi Hartamai Pancanita , Permata Sari Indah , Alexander Edwardo
Published: December 2021

Acid mine drainage (AMD) from coal mining activities contains Fe and Mn concentrations that often exceed environmental quality requirements. This study aims to determine the effect of the coal material size and temperature on the adsorption process of Fe and Mn metals contained in AMD using activated carbon made with a composition of 60% coal and 40% ZnCl2. For characterizing activated carbon, surface morphological was analyzed using SEM method, and surface area was analyzed using BET method. Meanwhile, for measuring Fe and Mn concentrations, the researchers used atomic absorption spectrophotometry. The adsorption process was carried out with various granular sizes of activated carbon (20, 28, 35, 48 and 60 mesh) and temperature (25, 35, 40, 45 and 50°C). The results showed that the maximum adsorption of Fe was 100% occurred in the treatment with an activated carbon size of 60 mesh and a temperature of 45°C, while the maximum adsorption of Mn was 11.91% in the treatment with an activated carbon size of 60 mesh and a temperature of 50°C. Furthermore, the activated carbon of coal is highly effective as an adsorbent for Fe in AMD waste but less effective for Mn.
Effectiveness of carbon active processed from coal in treating the acid mine drainage at a laboratory scale
Authors: Suliestyah  , Jamal Tuheteru Edy , Permata Sari Indah , Wisnu Fajar M
Published: December 2021

Low to medium calorie coal reserves dominate Indonesia area. Referring to such amount, the potential for coal synthesis into activated carbon is also massive. The potential utilization of activated carbon from coal to process the acid mine drainage is still developing. This research aims to see the effect of activated carbon to the acid mine drainage from coal mining in a laboratory scale using a weight basis and the contact time between activated carbon and acid mine drainage. The sample is taken from one of the mining locations in East Kalimantan Province. The results showed the effect of the activated carbon weight changes in its pH value, which indicated an increase in pH from 2.19 to a decrease in Fe metal content from 45.2 to 0.1 mg/L and a decrease Mn metal content from 7.22 to 5.3 mg/L. The activated carbon from coal is very effective as an adsorbent for Fe metal but less effective for Mn metal.
Social economic feasibility of community’s gold mining in Kertajaya Village, Sukabumi Regency, West Java, Indonesia
Authors: Prabawa F Y , Koestoer R H S , Sukhyar R
Published: December 2021

Many studies have stated that Community Gold Mining (CGM) activities are considered as poor and unqualified as a profession. CGM is also believed unfeasible for business, and has less impact to state’s economic system. In general, the mainstream theories believed that CGM is unsustainable. But in fact, informal CGM activities still exist everywhere. Is CGM really unsustainable? Is CGM not proper enough to be officially supported by the state? This paper discusses and examines the practice of CGM. The research location was in Kertajaya Village, Sukabumi Regency, West Java, Indonesia. There are thousands of local people working informally as CGM miners, with gold processing units Glundung/Tubes: Trommel Mercury (TM) method. 6 components of the Gold Production System were being discussed along with its their production costs. The observation was implied for TM processing units, carried out during 2018 - 2019. The supporting data were taken from CGM site: Cijiwa Block, from 2013 to 2017. The results: CGM business in research location is feasible enough, also has high economic potency for state’s taxation. Community’s Miner is qualifying as a profession, since the miner’s income exceeds the local minimum wage. Apart from the fact that the miners still use mercury, those facts show local CGM activity can be sustained.
The role of iron and nickel smelters for the Indonesian steel industries
Authors: Cahyaningtyas D , Suseno T , Rochani S , Yunianto B , Rodliyah I , Hartono
Published: December 2021

The iron and steel industries play a crucial role in supporting national development. The high dependence on imported raw materials causes Indonesia to suffer US $ 2.11 billion steel trade deficit per year. This study identifies the role of iron and nickel smelters in supporting the development of steel industries. The methodology used is descriptive statistics and regression models. Ferronickel and nickel pig iron as the primary raw materials for stainless steel have been produced in Indonesia, but only 23.05% and 47.77% are sold domestically. According to the linear regression models, it is expected that steel production and consumption will grow. Indonesia will become an independent steel producer and even export it by 2050. However, the supply chain is weak and poorly integrated as the local raw materials do not meet the domestic steel industry’s specifications. By 2050, 44 million tonnes of scrap, 19 million tonnes of sponge iron, 16 million tonnes of nickel, and 10 million tonnes of other raw materials will be needed annually. Hence, to reduce the national steel trade deficit, Indonesia must increase the smelters capacity and optimize local iron resources by increasing Fe content to meet the specifications of the national steel industry.
Multi-purpose inhibitors for the oil industry
Authors: Driker B N , Protazanov A A , Tsirulnikova N V
Published: December 2021

The issue of mineral scale formation in pipelines and technological equipment and metal corrosion of continues to be relevant for industrial plants, including oil-producing and oilrefining industries. The simplest and most available way to solve these problems is to use organophosphonates (OP) and low-molecular-weight polymers (MM<1000) as inhibitors. Complexonates with alkaline-earth metals (Me) have been synthesized on basis of mentioned above acids at different molar ratios OP:Me = 4:1 – 1:1 and temperature of 20 °C. Compositions containing synthesized complexonates were used for water of various degrees of mineralization and temperature range of 60-90 °C under dynamic conditions. It was found that the efficiency of inhibition of mineral scale formation for all the studied compositions of complexonates increase with the growth of number of functional groups in the OP molecule, regardless of the molar ratio of OP:Me. The corrosion inhibition both depends on the number of functional groups in the OP molecule and is determined by the formation of a protective film on the metal surface largely.
RETRACTED: Co-existence of Epiphytes on Eucheuma Denticulatum (Rhodophyceae) in Varying Depths Cultivated with Verti Net Method
Authors: Wati N , Kasim M , Salwiyah S
Published: December 2021

The existence of macroepiphytes is one of the issues seaweed farmers often face. This research aimed to explore the co-existence of macroepiphytes with seaweed Eucheuma denticulatum at varying depths using verti net method. Results showed that the highest and the lowest density of macroepiphyte were obtained on day -10 in the depth of 50 cm and 200 cm at 248,4 and 121,28 ind/m2/day, respectively. On day-20, in the depth of 100 cm and 200 cm the densities were 333,54 and 270,01 ind/m2/day, respectively. The most dominant macroepiphyte y is Chatomorpha crasa. Physical and chemical parameters showed a temperature of 29°-30°C, current velocity of 0,050-0,067 m/sec, brightness 92%, salinity 30-33‰, nitrate 0,237-0,0416 mg/L, phosphate 0,0015-0,0036 mg/L and dissolved oxygen 5,7-6,2 mg/L. The obtained optimum environmental parameters and the type of the macroepiphytes did not show any significant negative effect on the growth of E. denticulatum.
Fisherman Community Development Model with Disaster Mitigation Perspective in Meranti Islands Regency
Authors: Darwis  , Ramadona T , Septya F , Nugroho F
Published: December 2021

Meranti Islands Regency has coastal natural resources. On the other hand, this area also has the potential for natural disasters (coastal) and non-natural disasters that threaten the sustainability of resources and community welfare, so disaster mitigation efforts are needed. This study aims to formulate a model for developing Fisherman communities with a disaster mitigation perspective. This study uses MPE analysis and prospective analysis. The strategic basis for developing fisherman communities is increasing food security through the developing coastal based green industries, capacity building for local competitiveness and conservation of endemic species, and allocating budget proportionally to create local-based economic infrastructure and facilities development. The potential natural disasters that are more dominant in Meranti Islands Regency are abrasion, landslides, high waves and tidal flooding. A non-natural disaster is Covid-19 pandemic. Mitigation must be done is planting mangroves, building sheet piles, social engineering policies must be done by planting mangroves, building sheet piles, social engineering policies, and planting mangroves, building sheet piles, social engineering policies, and alternative livelihoods. The model for developing Fisherman communities with a disaster mitigation perspective in Meranti Islands Regency is optimizing coastal areas’ productivity and livelihood support systems.
The Effect of Trust on the Fishing Industry Supply Chain Performance in Rokan Hilir Regency Riau Province, Indonesia
Authors: Yulinda E , Supian K , Saad M
Published: December 2021

This research was conducted in August-October 2020 in Rokan Hilir Regency, the largest central of the fishing industry in Riau Province, Indonesia. The research objective to analyse the effect of trust on the fishing industry supply chain performance in the regency. Respondents were set 270 fishing companies based on the Slovin formula. They were taken purposively in four fishing centres, namely Panipahan (Pasir Limau Kapas district), Bagansiapiapi (Bangko), Kubu Babussalam, and Sinaboi. Collecting data using a closed questionnaire, containing a number of statements measured by a 7-point Likert scale. The data collected includes trust (credibility, top management capability, and government support), and supply chain performance (smooth of goods flow, financial flow, and information flow). Data analysed using the Structural Equation Modeling-Partial Least Square (SEM-PLS) method with the help of SmartPLS 3.3 software. The results showed that the trust has a positive and significant effect on the fishing industry performance in Rokan Hilir. This happens because the relationship between fellow entities of fishing industry supply chain occurs based on trust. The relationship between fishing companies (fisherman) and tauke (fish collectors, agents, and exporters) is based on patron-client ties, while the relationship between fellow tauke is based on family/blood ties. Both types of relationships have existed for years.