Epoxy compounds are commercial products that can be used as stabilizers, plasticizers in PVC (polyvinyl chloride) and can be used as antioxidants in natural rubber processing, a s surfactants, anti-corrosive additives in lubricating oils and pesticide raw materials. Epoxy compounds produced by the reaction between unsaturated fatty acids and peroxy acid. The raw material in this research is papaya seed oil. The purpose of this research is to study the combination of catalyst concentration, the amount of H2O2 (mL) and stirring speed (rpm) on the characteristics of the epoxy compounds. In this study, the fatty acids contained in the raw material were reacted with hexane, glacial acetic acid, H2O2 with variations of 40 mL, 50 mL, 60 mL, and 70 mL, sulfuric acid as a catalyst with variations of 1.5%, 2%, 2.5%, stirring speed with variations of 400 rpm, 500 rpm, and 600 rpm for 180 minutes. The results showed that the best epoxy compounds results were obtained at a catalyst concentration of 2.5%, 70 mL H2O2, and a stirring speed of 600 rpm, which obtained an oxirane oxygen number of 3.52, an iodine number of 10.4058 and an oxirane oxygen conversion of 73 .76471 %.

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Soil erosion is a natural disaster which frequently takes place in the Northern region of Thailand. Soil erosion causes loss of lives and properties of residents. This study was aimed to integrate a geo-informatics technology with the Universal Soil Loss Equation (USLE) in order to analyze areas which are prone to soil erosion in Nan Province, Thailand. The operation was performed by analyzing 6 factors of USLE including Rainfall erosivity (R-factor), Soil erodibility (K-factor), Slope length (L) and slope steepness (S), Cropping management (C), and Conservation practice (P) with overlay analysis being adopted as the last method. It was found from the analysis that the severity of the soil-erosion prone areas of Nan Province constituted 5 levels that included the least severity of 2,120.192 km2, the less severity of 2,728.851 km2, the moderate severity of 2,937.822 km2, the much severity of 2,133.648 km2, and the most severity of 1,551.5584 km2. The findings from this study can be embraced as a guideline to plan on the conservation and the management of land, and applied in a decision making process related to the land use planning in Nan Province, Thailand.

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Epilepsy causes rapid and revertible changes in the functions of the brain due to the constant occurrence of recurrent seizures. For the epileptic detection and classification, Electroencephalography (EEG) signals are used as this can relate the functions related to the activities of the brain. This paper presents the performance analysis of Approximate Entropy (ApEn) as a Feature Extraction Technique and Fuzzy Mutual Information (FMI), Linear Graph Embedding (LGE) as Dimensionality Reduction Techniques followed by the Application of Principal Component Analysis (PCA) as a Post Classifier for the Classification of Epilepsy Risk Levels from EEG signals. The benchmark parameters used for the analysis here are Performance Index (PI), Quality Values (QV), Specificity, Sensitivity, Time Delay and Accuracy.

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Catfish fat was pre-filtered to catfish oil. Catfish oil was chemical converted to esterified catfish oil by the epoxydation reaction and ring opening reaction of epoxidized catfish oil. Base on the formula of SAE20W50 engine lubricants, bio-lubricants were blended by replacing mineral base oil (SN500) as esterified catfish oil in ratio (wt/wt) at 10/90, 20/80, 30/70, 40/60 and 50/50. FT-IR method was used to identify functional groups of samples. The oxidation resistance of samples was determinated by TGA method and Rancimat test. The biodegradability of samples was analyzed by COD test and BOD test. Properties of material and products were determined by TCVN standard and ASTM standard. From the analysis results show that, esterified catfish oil can used as bio-based oil and blend of ratio of (wt/wt) esterified catfish oil/SN500/ at 40/60 can not only meet the characteristics of SAE20W50 lubricant but also it may be high biodegradability. The synthesis esterified catfish oil from catfish fat and preparation of bio-lubricant from esterified catfish oil can develop in green chemistry.

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The article highlights the principle of creating a control system for a two-motor asynchronous electric drive. The principle is based on the identification of the electromechanical time constant of each motor. Based on this, the adjustment of the number of revolutions of the “slave” electric drive to the number of revolutions of the “master” electric drive is achieved. The developed experimental unit for rotating a large object consists of the following elements: a rotation frame, a two-motor electric drive, a control board based on an ATmega2560 microcontroller, digital highly precise angular movement sensors, as well as power converters and reducing gearboxes. The obtained result of time of the transition process of synchronization of speeds satisfies theoretical calculations but requires optimization for real industrial facilities.

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The purpose of the study is to improve methods for predicting methane emissions from adjacent coal seams to longwall goafs. To assess prediction efficiency, an analysis was carried out of the existing methods for calculating the parameters of gas emission zones in overlying and underlying coal seams. Different methodologies were analyzed that are used by both companies developing Russian coal basins and those operating in top coal-producing countries (China, the USA, and Australia). As a result of the analysis, it was concluded that the methodology described in one of the coal mining regulations currently in force in Russia does not take into consideration a number of important factors that have a significant impact on methane emissions to longwall goafs. The article demonstrates that it is necessary to take into account such parameters as panel width and the depth of cover. To confirm that the depth of cover affects the permeability of underlying and overlying coal seams in the zones of stress relief, numerical models describing such zones were developed using the finite element method. Numerical modelling was carried out using a 2D rock mass model that included three coal seams (underlying, overlying, and the one being developed), mine workings, and a goaf. The Mohr-Coulomb model was used to describe rock behaviour under stress. By comparing stress distribution patterns at depths of cover of 300, 500, and 900 m with a 300-m distance to the overlying seam and a 50-m distance to the underlying seam, it was concluded that the extent of the gas emission zone created by the underlying seam significantly exceeds the value specified in regulations (35 m) and depends on the depth of cover. It was also established that the effect of stress relief (i.e. an increase in the effective porosity and permeability of the seam) on the seam being overmined increases along with growth in the depth of cover. This dependence is explained by the fact that changes in stresses under the goaf become more significant at greater depths. The novelty of the study consists in identifying a significant effect of stress relief on permeability that manifests itself and great depths of cover and in providing a rationale for improving the methodology for predicting methane emissions from coal seams being overmined at Russian mines by taking into account changes in effective porosity that depend on the depth of cover.

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In this paper described technogenic impact of radionuclides on oil and gas facilities. When oil products are spilled on the surface as a result of accidents in the oil and gas industry, they are further filtered to the depth of the soil, which leads to the accumulation of radionuclides in the soil. Natural radionuclides then migrate to plants and further along trophic chains. Natural radionuclides that contribute to external ? radiation enter natural sources - air, water, soil. Today, soil pollution by oil products is one of the most acute environmental problems, as it contributes to the growth of radioactivity in the environment. The components of bitumen and paraffin in the oil entering the soil lead to significant changes in the properties of the soil profile. The gamma background in the region averages 0.11 to 0.20 µSv / h. In Kyzylorda region, hazardous wastes with the possibility of radionuclides include oil wastes, including drilling mud and used ingredients. Development of the Kumkol field began more than 30 years ago (1986). If a large area of oil and gas production areas is not treated and completely cleared of waste over decades, it will have a permanent negative radiation effect on humans and the biosphere.

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The risk of accidents due to rollover of heavy vehicle is an issue that has always been studied in many countries, one of the most widely used factors to determine the vehicle’s stability is the Static Rollover Threshold. For the calculation of this factor, the movement of the center of gravity is taken into account, which is affected by the vehicle and road characteristics. This is extremely important since through its use can predict how the behavior of certain vehicles will be in certain sections of a road, thus making it possible to establish safe speed limits for these vehicles. Taking into account this, and using the Static Rollover Threshold a rollover risk analysis is carried out in some critical points of the highway Pamplona-Cucuta to determine safe speed limits.

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Power-law fluids are very common in the oilfield industry. Engineers find them in completion and stimulation treatment works when using such fluids as polymers, foams and some heavy crude oils which obey a non-Newtonian model. Therefore, engineers must be able to identify and characterize pressure transient behavior on such systems. Several expressions have been developed to find reservoir permeability and skin factors. The most recent use the TDS Technique which basically uses some characteristic points and features on the pressure and pressure derivative versus time log-log plot. In this work a modification of the TDS Technique is introduced to account for a shorter version of a pressure solution model that makes a slight change in the determination of the slope of the pressure derivative curve during radial flow regime. The proposed simplification initially came with a trial-and-error procedure which is somehow tedious. Although, the variation is small, a tremendous impact on the permeability and skin factor calculation is found with absolute error values up to 76%.

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In this study, the falcata sawdust was utilized to produce briquettes. The samples were produced using a single mold manual briquetting device. The falcata sawdust was mixed with three binders namely cassava starch, paper pulp and molasses at 70:30, 60:40 and 50:50 sawdust-to-binder ratio and were then evaluated in terms of its calorific value, boiling time and durability. Results showed that the calorific value of briquettes decreased as the sawdust-to-binder ratio is increased. Briquette samples with 70:30 sawdust-to-binder ratio can boil water in a shortest period. Meanwhile, the the durability of briquettes increased as the sawdust-to-binder ratio is increased. Among the binders considered, cassava starch has the highest durability followed by paper pulp. Further, a manually-operated briquetting machine that can produce 25 briquettes with an average production time per batch of 5 minutes was fabricated. The said machine can produce 300 briquettes per hour.

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This paper describes an experimental screw press for juice and cake separation. The constructive and structural schemes of the press are given, the characteristics of the main units of the equipment and the principle of its operation are presented. The algorithm of engineering calculation of juicer design is resulted, which is based on the calculation of pressing duration at different rates of screw rotation (? = 14653 rad/s, ? = 12,56 rad/s, ?  = 16,75 rad/s, ?= 18,84 rad/s) and studied influence of compression pressure by changing of diaphragm holes (d=6•10-3 m; d=10-3 m; d=10•10-3 m; d=12•10-3 m). The proposed method of engineering calculation of the pressing process makes it possible to determine the optimum parameters in advance and to develop a press of any capacity depending on production conditions.

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