bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD and experimental analyses of flow distribution uniformity in minichannel reactors with a bifurcation structure manifold
Authors: Zhuang X R , Xu X H , Li L , Xin X , Xu W F
Published: October 2019

This study investigated the flow distribution uniformity and pressure drop in minichannel reactors with a bifurcation structure inlet manifold and different type outlet manifolds. The numerical model was established and validated by experimental results. In order to analyze the effects of structural parameters on the flow distribution uniformity of the manifold, the bifurcation inlet manifold was first designed based on the principle of minimum entropy generation. The results showed that longer channel length of bifurcation in the inlet manifold allowed the flow to be fully developed and equally split into several flows. Then, with an identical bifurcation inlet manifold, the influences of outlet manifold with structures of bifurcation, triangle and rectangle, as well as the parallel minichannel length on the flow uniformity of minichannel reactors were also built and investigated. The results showed that the rectangular structure outlet manifold simplified the structure of minichannel reactors and reduced the parasitic power consumption. The flow uniformity of minichannel reactor increased as the parallel minchannel length increased and the impact was more significant at high inlet flow rate than at low inlet flow rate.
Study on the points and countermeasures of quality control in the wind turbine blades
Authors: Wang B J , Zhao Y , Zhang R G , Yang B , Xie X J
Published: October 2019

There are many problems in the technological development, research investment, staff ability and industrialized level of domestic wind turbine blade. This review summarizes the quality situation of wind turbine blade in the production process and proposes some advices and solutions in the further development of domestic wind turbine blade.
Research on voltage coordinated control strategy of large-scale renewable energy access to grid optimization
Authors: Huang W , Yang R , Shi J F , Yuan X T , Liu Y , Ding R Y , Zhan L Y , Yang Z L
Published: October 2019

With the increasing consumption of traditional energy sources and the destruction of the environment, traditional energy generation cannot meet the development of today’s society. Replaced by renewable clean energy, a large number of new energy access to the power grid, but large numbers of unconstrained access to the grid will seriously cause problems with unqualified voltage quality. In this paper, the reactive power demand Q of the grid is determined based on the difference between the measured voltage value and the voltage target value collected at the grid point exceeds the allowable range. And by calculating the SVG reactive power adjustment margin of each new energy power plant. For the adjustment margins of reactive power compensation equipment in each new energy power plant, reactive power distribution is implemented using strategies such as equal ratio or equal margin or priority allocation.
A comparative study on effects of various insulating layers of roof system on energy usage of building envelope
Authors: Raut A , Khatoon S , Goud P
Published: October 2019

The purpose of paper is to analyse the effectiveness of various roof systems based on insulations layers in hot climatic condition of Hyderabad, India. In this paper, Energy analysis using Autodesk’s Green Building Studio cloud computing software has been done. The Energy analysis results gives indication about the Energy usage of building as well as overall life cycle costing. The roof system has been studied with their carbon emission and Embodied Energy to understand the sustainability aspect of the insulating layers in combination to provide a green roof system. The materials used for studying the insulating effects of roof system which were analysed in combinations were cork, gypsum board, expanded polystyrene, rock wool, fibre glass, PVC mesh, Polyurethane, etc. Due to the insulating layers the heat transfer is reduced through the roof system, which affects the cooling load of building envelope which reduces the energy consumption. The study is significant to understand the occupant’s indoor comfort, environmental and long-term economic benefits of insulation for a building envelope.
Research on challenges and feasibility suggestions of inter-regional environmental coordination
Authors: Fa L N
Published: October 2019

Many countries along the Silk Road have their own characteristics in economic and political aspects. This study expounds the challenges faced by international environmental law construction. The difficulties in the formulation of international environmental legal documents, the differences between countries, and the lack of technical means of environmental protection make environmental development face difficulties. International and domestic lack of incentives for environmental protection has also become one of the problems. In the face of this dilemma, the governments of all countries should strengthen the international cooperation in environmental protection and promote the scientific means of environmental protection, cultivate the awareness of environmental protection among the people of all countries, and achieve the situation of harmonious development of environment and economy.
Multi-parameter Joint Optimization Based on Steam Turbine Thermal System Characteristic Reconstruction Model
Authors: Liu S , Shen J , Wang P H
Published: October 2019

Steam turbine thermal system characteristic reconstruction model for multi-parameter joint optimization is proposed in this paper. This paper has two main improvements. First, a steam turbine thermal system characteristic reconstruction model is conducted, which includes turbine, condenser and heater. There are three iterative nested algorithms in this model. In the innermost layer, avariable condition calculation model of condenser is nested, and the exhaust flow and exhaust steam pressure can be calculated. In the outermost layer, the power equation is applied as the iteration ends. In this model, simulation of thermal system of steam turbine three kinds of disturbing factors demand can be realized well and the joint optimization of thermal system of steam turbine flow section and the cold end can be realized. Through calculation and comparison, the model constructed in this paper is proved to have high accuracy, and the calculation process is stable and convergent. At the same time, the joint optimization method involving turbine main steam pressure and exhaust pressure is proposed here. In this method, heat consumption rate is the optimization objective, with steam turbine thermal system characteristic reconstruction model, the optimal main steam condenser and vacuum pressure were obtained. The result of A 600MW condensing unit showed that the method could be synchronized to determine the optimal combination of circulating pump, the best vacuum and sliding pressure curve of main steam under different load and different ambient temperature. Comparison results also showed that the joint optimization solution of main steam pressure and exhaust pressure is superior to optimized solution main steam pressure individually.
Mathematical Modelling of Drying Kinetics in the Natural Solar Drying of Mango
Authors: Touré S
Published: October 2019

There are several drying kinetic models. Some of them are theoretical, semi-theoretical or empirical. Among them, several are based on the Fick’s second law. Those models generally use some constant coefficients for the whole drying process. The present model uses the water speed of transfer. It is correlated to the drying rate, to the drying time and to the modelling parameters. Finally, the drying rate and the moisture content are expressed as functions of those parameters and the drying time. The modelling parameters, which are time dependent, are calculated from the experimental drying data. In a previous work, our mathematical model was applied in the modelling of natural solar drying of plantain banana. In the present work, the model is applied in the modelling of natural solar drying of mango. The drying rate is estimated with a high accuracy, as the relative errors between experiment and theory are in the range 0.03 % - 7.7 %. By way of comparison, the modelling performed using the characteristic drying curve yields relative errors varying between 11.37 % and 84.47 %. In the same way, the moisture content is estimated by our model with a high accuracy, as the relative errors lie in the range 0.003 % - 1.1 %. The modelling of the moisture content carried out using the Henderson and Pabis model yields an estimate with relative errors varying between 1.8 % and 5.26 %.
A novel anode material for lithium-ion batteries: silicon nanoparticles and graphene composite films
Authors: Zhang P B , You Y , Wang C , Fang X H , Ren W , Yang L Y , Chen XY
Published: October 2019

Silicon nanoparticles (Si NPs), with tremendous theoretical capacity, have been extensively studied how to be combined with graphene to form stable anodes for lithium-ion batteries. In this paper, a novel approach, chemical vapor deposition (CVD), is proposed to synthesis Si NPs and graphene composite film anode. Si NPs are well dispersed with carbon nanotubes in N methyl pyrrolidone solvent, spin-coated onto Cu foil as substrates to grow graphene, and successively and diversely embedded in graphene film, which is fabricated into anodes for lithium-ion batteries with high capacity of 1115.2 mAh/g. It is demonstrated a possible and promising method to prepare anode material for lithium-ion batteries.
Three-dimensional effects of trailing edge flap and winglet integrated on up-scale wind turbine blade
Authors: Motsamai O S , Muiruri P I
Published: October 2019

Wind turbines must generate wind power cost-effectively for the wind power to remain viable and competitive among other renewable resources. The rotor diameter continues increasing in size to capture more energy to reduce the costs of wind power. However, the size of the rotor diameter is expected to reach limit due to restrictions related to the rotation of the entire blades, transport, and installation issues. This study, therefore, seeks to compare the effects of trailing edge flap and winglet embedded on the up-scale wind turbine blade. The investigated configurations are blade with winglet, blade with trailing edge flap and blade with a combination of the winglet and trailing edge flap. A straight blade of the NREL 5MW wind turbine was used as a benchmark to quantify effects of trailing edge flap and winglet. All simulations were performed using the ANSYS FLUENT. The steady pressure-based solver in absolute velocity formulation modelled the flow over the blade surfaces governed by Reynold-Averaged Navier-Stokes (RANS) equations closed with the k – ω SST turbulence model. Blades with trailing edge flap and combined trailing edge flap and winglet show similar effects in comparison of pressure coefficient at 0.32R, 0.60R and 0.92R. Blade with a winglet generates the highest aerodynamic torque, while blade with trailing edge flap decrease most of the flap-wise bending moment. The blade with combined trailing edge flap and winglet can serve as an alternative design for improving the wind turbine performance. That is, at the normal operating condition the trailing edge flap can be held at its neutral position whenever increment of the power is the primary target.
Multifractal Spectrum Identification of Partial Discharge in GIS Based on Optical Detection
Authors: Xie R , Ge X Y , Zhu J P , Hu R P , Zhou F K , Zhang X X
Published: October 2019

Partial discharge (PD) pattern recognition is an effective means to accurately obtain the correspondence between PD features and insulation defects. Optical detection for PD has strong anti-interference ability. Therefore, this paper carried out research on the pattern recognition of PD optical signal. In this paper, the PD optical signal under four typical defects of gas-insulated switchgears (GIS) are obtained by fluorescent fiber sensing system, and the four kinds of grayscale images are established. The multifractal spectrum features of the grayscale images of the optical signals are extracted. By analysing the physical meaning of each feature information in the multifractal spectrum, the feature components for PD pattern recognition are extracted, and the improved conjugate gradient back propagation (BP) neural network algorithm is selected as the classifier. This paper show that the multifractal spectrum can effectively describe the degree of unevenness of PD grayscale images and the geometric features of different level. The correct recognition rate of all kinds of defects by the multifractal spectrum is more than 87%, which is better than the identification of the box dimension and information dimension as the feature components. It lays the foundation for the future application of the optical detection.
Design of distributed power quality monitoring system for distribution house
Authors: Luo J P , Han L Q , Yuan L L
Published: October 2019

The construction of smart grid puts forward higher requirements for power quality. As the key node of power distribution system, power quality monitoring of distribution room has always been the weak link of power operation and maintenance. This paper presents a distributed power quality monitoring system for distribution room, which includes hardware design and software design. It has the functions of acquisition, analysis, display and communication. It can complete distributed power quality monitoring for multiple outgoing branches of distribution room. The application of this system can provide data support for power quality analysis and management of low-voltage distribution system.
Smart park integrated management cloud platform architecture based on microservice governance framework
Authors: Huang D , Jiang G D , Sun B H , Feng R Q , Wu J P
Published: October 2019

Nowadays, the park and its enterprises face many challenges in the global environment that is service-oriented, customer experience centered and customer demand oriented. ICT is becoming a major promoter and partner for smart parks and modern businesses. The smart park takes advantage of the results of data integration and sharing, and provides decision-making through data analysis, making the park more “intelligent” for corporate and individual services. An integrated management cloud platform architecture of smart parks based on the micro-service governance framework is proposed in this paper, which adopts the springclass micro-service governance framework to solve the problems of “data island”, “power island”, and “user experience” among the information subsystems of smart parks. The information and services will be integrated well to make quick response to changes in the extensional needs of the park’s operational services, and to achieve high scalability the system.
Research on Harmonic Suppression of High Temperature Boiler Based on Three-phase PWM Rectifier
Authors: Zhang Q , Qian P
Published: October 2019

Traditional boiler temperature control is based on thyristor voltage regulation, and the output AC voltage is controlled by controlling the trigger angle α of thyristor, so that the boiler temperature can be controlled in the pre-set range. However, this way of voltage regulation and temperature control will cause serious harmonic pollution to the power grid, and the output current has high harmonic content and low power factor. At the same time, the traditional three-phase load connection mode generally adopts star connection, and the load is pure resistive silicon carbide. Because of long-term use, the aging of silicon carbide heating rod is different, in fact, it is asymmetric load, three-phase load. The unbalance will cause three-phase unbalance, which will make the voltage of a certain phase exceed the rated working voltage of the heating rod, and greatly reduce the service life of the heating rod. Therefore, in order to improve the efficiency of power supply, reduce harmonic pollution and solve the problem of three-phase unbalance, this paper proposes a three-phase PWM rectifier circuit, which converts AC to DC, and realizes DC voltage regulation and temperature control through PI regulator. In this paper, the feasibility of the scheme is verified by simulation and comparative analysis.
Model Predictive Current Control with a Fixed Switching Frequency for Power Factor Corrected Rectifiers in Microgrid
Authors: Hong Y M , Lin Q B , Zong Y , Shi Y , Su X J
Published: October 2019

In this paper, a model predictive current control (MPCC) strategy with a fixed switching frequency to control the dual boost bridgeless power factor corrected (PFC) converter is proposed. The improved MPCC strategy solves the problem of filter design and the high electromagnetic interference (EMI) which caused by the traditional MPCC. With the consideration of a nonlinear inductor, a formula is fitted to represent the change of the inductance, and the improved strategy has strong robustness. The simulation and experiment shows that the quality of current and power factor of the system is improved by the proposed control strategy.
Data mining and data driving of harmonic in AC arc furnaces based on functional analysis
Authors: Deng P , Xu X , Wang F Y , Chen Z
Published: October 2019

This paper use big data technology, mine synchronous harmonic measuring data of AC arc-furnaces whole production process with functional analysis, verifies that harmonic current released from AC arc-furnaces is in independence and orthogonality approximately between each other. The discovered knowledge shows that multi-arc-furnaces harmonic current can be largely counteracted each other, If these AC arc-furnaces were connected to a PCC in which short-circuit capacity is enough for that the superposed harmonic current of AC arc-furnaces can be electromagnetic compatible, then power quality of the PCC can reach the qualified level discovered knowledge further reveals the model of AC arc-furnace, disorder data stream generated from harmonic measuring data is derived to calculation composition harmonic current at PCC(Point of Common Connection) in which AC arc-furnaces were connected.
Greenhouse Gas emission determination of typical infrastructure in High Andean cities: Study Case Ambato city-Ecuador
Authors: Mayacela C , Núñez G , Cañizares B , Moya D
Published: October 2019

The building sector is one of the most important commercial activities all over the world, being one of the main producers of Greenhouse gas (GHG) emissions. In the current investigation an evaluation of the emanation of Carbon Dioxide equivalent (CO2e) was performed to different of typical buildings in Ambato city, Ecuador. It was applied the GHG Protocol and ISO 14064-1 standards for companies and organizations. The GHG emissions calculation was based on the most representative work volumes of typical buildings of this Andean city, and its corresponding emission factor. The results show that structure type III emits more CO2 because more structural steel, concrete and clear glass are used in its construction due to its architectural and structural design.
The Economic and Environmentally Friendly Tree Felling Techniques in Natural Forest
Authors: Suhartana S , Yuniawati
Published: October 2019

Improper tree felling techniques may reduce productivity and log supply. This leads to an increase in production cost. Timber Utilization Efficiency (TUE) in natural forests has not been optimally implemented, thus leaving residual stands with tremendous damages. This study was carried out in late 2015 in PT Inhutani II, North Kalimantan to investigate the implementation of felling techniques and to analyze felling productivity, TUE, production cost, and residual stands damage. Productivity, felling cost, and TUE data were tabulated and averaged. Results revealed that: (1) tree felling techniques implemented on the site were the reduced impact logging (RIL) technique; (2) the average felling productivity and production cost were 38.308 m3/hour and IDR 13, 935.10/m3, respectively; (3) the average TUE was 92%, with only 8% generated-wastes; and (4) the average destruction of residual stands was 13.54%, which comprised of canopy damage, broken/cracked, stem injury, and leaning.
Application of chromatographic fingerprint technology in study of single layer capacity contribution of multi-zone shale oil well in Jimsar Sag
Authors: Li Erting , Jin Jun , Liao Jiande , Chen Jun , Hou Dujie , Jiang Yuhan , Mi Julei , Zhang Ziming
Published: October 2019

Based on the principle of chromatographic fingerprinting technology, P2
l
2
2-1, P2
l
2
2-2and P2
l
2
2-3 single layer shale oil chromatographic fingerprint libraries of upper sweet spot in Jimsar Sag were established by laboratory matching experiment. The partial least squares method was used to realize the capacity contribution calculation and dynamic monitoring of the single layer in two layer and three layer shale oil of the dessert in Jimsar. The result shows, upper sweet shale oil of Lucaogou Formation in Jimsar Sag are mainly supplied by P2
l
2
2-1 layer and P2
l
2
2-2 layer. Oil mainly supplied by P2
l
2
2-1 layer in the wells of JI 37 and JI 171, which are combined with P2
l
2
2-1 and P2
l
2
2-2. Oil mainly supplied by P2
l
2
2-2 layer in the wells of JI 25 and JI 173, which are combined with P2
l
2
2-2 and P2
l
2
2-3. Oil mainly supplied by P2
l
2
2-1 layer in the wells of JI 174 and JI 176, which are combined with P2
l
2
2-1, P2
l
2
2-2 and P2
l
2
2-3, followed by P2
l
2
2-2. In addition, it is found that with the progress of oil exploitation, the contribution rate of P2
l
2
2-1 in JI 174 well and JI 176 well is gradually reduced, and P2
l
2
2-2 becomes the main oil supply layer. The physical properties and oil saturation of the corresponding reservoirs in each well were analyzed. And the results proved the accuracy and rationality of the calculation results.
New insights on Muglad’s Cretaceous source rocks: a paleo-geographic review & organic geochemical characterization, Muglad basin, Sudan
Authors: Omer Fadul Abul Gebbayin I M , Zhong N , Luo Q , Abu Elgasim E , Shi S
Published: October 2019

Pyrolysis, chromatographic, and isotopic techniques were applied to study a suite of (174) rock cuttings from Muglad’s block 2 & 4, aiming at identifying and fully characterizing the potential source rock/s in the basin. Two source rock units were recognized and described as good-very good for hydrocarbon generation in the study area. These include the middle Early Cretaceous Abu Gabra and the top Late Cretaceous Baraka formations. The former consists of a good-very good organic rich shales (TOC = 1.0-4.0 %, S2 >20 mg HC/g TOC), of mixed kerogens dominated primarily by the oil prone type-I (HI = 600 mg/g) in association with few type-III, and is currently thermally mature for hydrocarbon generation in the basin peripheries and over mature in the centre. The Baraka displays a wide hydrocarbon generative potential ranging from fair to very good (TOC = (0.5-4.0%) and S2 yield of (2.0-20 mg HC/g TOC), of mainly type-II oil and gas prone kerogen (HI = 450 mg/g), and thermally mature for hydrocarbon generation in the basin centre only.

Biomarker characteristics of the analyzed samples reveal three main organofacies units; a (I) freshwater oxic to sub-oxic clay-rich Early Cretaceous distal lacustrine, (II) a highly anoxic, and clay-poor Late Cretaceousdistal marine, and a (III) proximal lacustrine and/marine of both E. and L. Cretaceous. Organofacies-I shows relatively high ratios of: [Pr/Ph (1.2-3.02), C26/C25 tricyclic terpanes (1.11-3.12), Ts/Tm (0.95-1.33), gammacerane indices (0.14-0.50), and diasterane/regular steranes] with low: [tri- and tetracyclic terpanes, C17/C25 n-alkanes (1.0-1.5), C29/C30 hopanes (0.55-1.14), and pregnanes & homopregnanes]. Organofacies-II inversely, is characterized by very low [Pr/Ph ratios (0.37-1.0) suggesting extreme anoxic conditions, C26/C25 tricyclic terpanes between (0.50-1.0), Ts/Tm (0.21-0.50), Gammacerane indices (0.05-0.22), and low diasterane/regular steranes (0.34-0.66)] with high: [tricyclic terpanes content dominated by the C23 variety, C24 tetracyclic terpanes, C17/C25 n-alkanes ratios (3.7-5.12), C29/C30 hopanes (0.4-1.11), and abundant pregnanes and homopregnanes]. Organofacies-III is amerely proximal sub-facies of the former two differentiated basically on the basis of the redox conditions of their corresponding depositional environments and amount of terrigenous organic matter supply. The isotopic data is fairly consistent with the biomarkers in delineating the same three organofacies units. We relate the marine input into Muglad basin during the L. Cretaceous to the global L. Cretaceous sea transgressions in Africa and thus foresee a booming new exploration opportunity in the basin.
Failure Analysis of the Semi-permanent Coupler Used in Metro Rail
Authors: Morsy M A , Khafagy S , Mosa ES
Published: October 2019

Failure analysis of the semi-permanent coupler which failed in service of Metro rail was conducted in order to know the reason for failure. The examinations include visual, photo detection, chemical analysis, hardness measurements, tensile and v-notch impact test, microstructure and SEM observation of fracture surface. Chemical analysis and tensile test shows that the coupler material can be classified as grade B cast steel in AAR M201 steel casting specification. Although the microstructure of the coupler material shows incomplete homogenization indicating the improper conduction of heat treatment, the v-notch impact results is accepted according to this specification. The fracture surface shows the existence of much porosity at the internal surface of the hollow like pipe- coupler and the fracture started at these sites showing beach marks. SEM observation of the fracture surface shows fatigue striations indicating the occurrence of fatigue started at the porosity defects. The cast defects act as a stress concentration site for fatigue crack initiation. Crack occurred, propagated, and connected the defects to each other. The occurrence of collision resulted in bending of the female part of the coupler (plastic deformation occurs) at the lower thin wall (∼ 5.41 mm thickness). Moreover, opening of the previously formed fatigue crack and accelerating the failure were occurred. Recommendations were explained to prevent the occurrence of this failure.
Assessing the Dispersion Quality of Carbon Nanotubes Suspensions by Low Field Nuclear Magnetic Resonance
Authors: Huang Yongping , Hong Shuxian , Li Weiwen , Guo Shijie
Published: October 2019

In this study, a novel method based on low field nuclear magnetic resonance measurements were used to characterize the dispersion quality of carbon nanotube suspensions. The liquid specific surface area, which calculated with the relaxation time, were used as an indicator of dispersion quality of the carbon nanotubes suspensions. The experimental results were compared with those measured by the conventional method methods, including Zeta potentiometer method and ultraviolet visible spectrophotometer method. The results show that low field nuclear magnetic resonance has the advantages in the characterizing the dispersion quality of high concentration carbon nanotube suspensions and tracking its re-agglomeration process non-destructively.
Facile Preparation of Ag-TiO2 Nanocomposite with Enhanced Photocatalytic Properties
Authors: Tian Tao , Yao Chuangye
Published: October 2019

For decades, photocatalytic semiconductor materials were regretfully limited to low-yield preparation method and poor catalytic efficiency although it has dramatically captured attention in sewage treatment applications. To expand this slim range of semiconductor catalysts, the nanocrystalline silver embedded in titanium dioxide (Ag-TiO2) heterojunction was prepared by means of facile mechanical milling technique capable of large-scale production, in terms of optimum Ag content. The as-obtained Ag-TiO2 nanocomposite particles were systematically characterized by means of X-ray diffraction technique, Raman spectra, X-ray photoelectron spectroscopy, transmission electron microscopy analysis, and UV-vis spectrophotometry. Results suggest that in comparison with pure TiO2 catalyst, Ag-TiO2 nanocomposite catalyst significantly enhanced photocatalytic activity for the degradation of methylene blue (MB), whereas its band gap decreased in view of the red-shift phenomenon. In terms of the experimental results, a mechanism was proposed to explain the enhancement of photocatalytic activity. Our findings offer a promising route towards the large-scale preparation of high-efficiency photocatalysts for commercial applications.
Four Amino Acid Residues in Acyltransferase Affect the Production of Epothilone A to Mixed Epothilones A and B
Authors: Sun Xin , Li Pengfei , Li Yuezhong , Zhao Lin
Published: October 2019

Surveying more than 100 native epothilone producing strains were isolated from different locales revealed that the production ratio of epothilones A and B was sorted into two groups, almost single epothilone A or approximate 2:1 ratio of A and B. Sequencing the second acyltransferase in the epoC module (ATModC2) of different Sorangium producers indicated that four amino acid residues at sites 90, 91, 95 and 196 in the enzyme active centre altered in parallel to the production ratio shift. In those producers with single epothilone A, ATModC2 had almost the same sequence and computational structure as ATModC1, which selectively accepts malonyl-CoA as the extender units.
Properties and Extraction of Crude Pectin Esterase from Potato (Solanum Tuberosum)
Authors: Li Jing , Li Xiaowan , Li Shanshan , Shen Guanghui , Luo Qingying , Wu Hejun , Chen Anjun , Zhang Zhiqing
Published: October 2019

In order to study the enzymatic properties of potato esterase, the crude enzyme of potato esterase was extracted with phosphate buffer solution, and the extraction conditions were optimized. The optimal condition is: the optimal condition for phosphate buffer solution pH 7.0, water bath time for 30 min, extraction temperature 35°C, and solid-liquid ratio 1:4 (g/mL). The property analysis showed that the potato esterase extracted from phosphate buffer solution was not a single esterase, but a kind of esterase isozyme. At 273nm and 325nm, the potato esterase crude enzyme had two characteristics uv absorption peak, its isoelectric point was near pI 4.4, and its molecular weight was roughly distributed at 16.4, 20.866, 22.73 and 40.286 KDa. In 40 °C ∼ 45 °C, under the condition of pH 7.0, better able to maintain its activity, and seven kinds of metal ions are inhibitory effect to it. This study provides a theoretical basis for further understanding the enzymatic characteristics of potato esterase and its application in pesticide residue detection.
Material Analysis and Design of New Household Humidifier
Authors: Zhu Zhiwei
Published: October 2019

With the continuous improvement of people’s living standards, more and more people have higher requirements for health and quality of life. Humidifier as an indispensable small household appliances product in dry areas, it has become part of people’s life gradually. This paper investigates the market of humidifiers, and material analysis of different humidifier products, and design and launch a new type of household humidifier. The positioning of this design is to meet the user’s purchasing needs for modelling, Requirements for modelling not only highlight the simplicity and atmosphere of the product, but also meet the needs of consumers. While improving the quality of life and family environment, it becomes part of the happy family memory.
Outgassing Environment of Spacecraft: An Overview
Authors: Jiao Zilong , Jiang Lixiang , Sun Jipeng , Huang Jianguo , Zhu Yunfei
Published: October 2019

With the advancements of materials science and technology, organic materials found significant applications in aerospace industry. But under the orbital thermal and vacuum environment, organic materials can outgas and the outgassed products and induced environment often degraded performances of spacecraft or its subsystem. In this article, the typical impacts of outgassing environment on spacecraft are explained briefly. Then the outgassing theory, test method, identification of compounds and control measures were reviewed in detail. The need for transient and long-term outgassing model is discussed. The standard test methods of E595 and E1559 are compared. The promising new techniques such as infrared spectrometry and/or mass-spectrometry with thermogravimetric analysis is proposed for the identification of outgassed compounds. The vacuum bakeout and molecular absorber for outgassing control are reviewed and for the last more research work is needed.
Analysis of Harmonic Propagation and Coupling among Wind Farm Groups
Authors: Miao Xujuan , Liu Jinming , Li Changling , Zhang Xinyan , Xu Qidan , Yue Jiahui , Sun Ke
Published: October 2019

Although wind energy itself has the conditions of large-scale development and utilization, power quality has always been the focus and difficulty of wind power generation. Harmonics generated by power electronic equipment in doubly-fed generators may lead to overheating damage and faults of transmission lines and transformer equipment. To improve the safe operation and harmonic control ability of power grid and reduce the loss of electrical equipment, a model of double-fed wind farm group with voltage level of 690V/35kV/110kV was established in Matlab/Simulink. By analyzing the characteristics of harmonic propagation and coupling between wind farms under different conditions, it is found that when the harmonic source was on the fan side, the harmonic is transmitted from the fan side to the grid side. If the harmonic content of wind power station is large, it will have a greater impact on power quality. In addition, due to harmonic coupling, 110 kV bus current has the highest harmonic distortion rate and the highest harmonic content.
Design of Zero-gravity Unloading Process Equipment for Satellite Overlapping Antenna on Ground Test
Authors: Fan Yougao , Liu Guangtong , Liu Li , Yang Chunsheng
Published: October 2019

In this paper, the zero-gravity unloading scheme and the design scheme of the zero-gravity unloading process equipment are proposed for the three-overlapping antennas of a communication satellite. Due to the particularity of the structure, test state and unloading state of the communication satellite antenna, the zero-gravity unloading simulation process equipment commonly used at present cannot meet the test requirements. Based on the analysis of the requirements of zero-gravity deployment test and the process of the three-overlapping antennas zero-gravity unloading, a solution to meet the test requirements is proposed. System performance tests verified the effectiveness of the zero-gravity unloading system.
The Research on Key Technologies of Power Quality Comprehensive Control in Complex Distribution Network
Authors: Wang Shuanghu , Yin Hongxu , Liang Shun
Published: October 2019

As new types of power sources and loads such as distributed photovoltaic and electric vehicle charging facilities are connected to the distribution network, the distribution network has become more variable and complex, and the simple distribution network has evolved into a complex distribution network. The access of new elements, especially the application of power electronic devices, has a great impact on the power quality of the distribution network. The technical framework of power quality comprehensive management of complex distribution network is proposed, and the corresponding technical route is put forward from three aspects: the influence of power electronic equipment application on power quality of distribution network, power electronic equipment modeling of distribution network, flexible monitoring of power quality and rapid control.
The Effect of Pole Density on Permeable Groin Due to Controlling Longshore Current
Authors: Umar Hasdinar , Rahman Sabaruddin , Paotonan Chairul , Baeda A.Y.
Published: October 2019

Erosion and sedimentation problems that occurs, usually solved firstly by finding the cause of erosion and sedimentation literally, due to determining the action to overcome them. In coastal engineering, there are two approaches that can be used to solve such kind of problems; which are the soft approach, i.e. beach nourishment, vegetation, sand by passing, coastal boundary policy; while the hard approach or structural approach are building breakwater, jetty, groin, sea wall and so on. In structural approach, the uses of permeable groin nowadays is one of the new ways to overcome the erosion and sedimentation problems in beaches. To find out how efficient the permeable groin can control the flow along the coast, so called longshore current, a research needed to be conducted focusing on the effect of pole density at permeable groin itself. The ability of controlling longshore current will be the main analysis, in such various variations of pole densities at the permeable groin. It found out that the pole densities of permeable groin can significantly controlled the longshore current; which is if the pole density become higher than the speed of longshore current can be reduced. It also found out that by implementing 40% of pole density, the longshore current can be reduce up 50% respectively.
Progressive Collapse Behaviour of VLCC under Longitudinal Bending
Authors: Rizkiani Tsumiratin , Ramadhan Muhammad Iqra , Alie Muhammad Zubair Muis
Published: October 2019

The aim of this study is to analyse the ultimate strength of VLCC subjected to longitudinal bending moments under hogging and sagging conditions. One-frame space in the mid-ship section of VLCC is taken to be assessed. The Nonlinear Finite-Element Analysis method (NLFEA) is adopted in this study. The boundary and loading conditions are applied on both sides of the ship cross section. The Multi Point Constraint (MPC) is imposed to the cross section based on the neutral axis references. The element type is SHELL 181 is used on the model. The meshing size is 500 mm, and the arc length method is applied to solved the load and shortening curve. The initial imperfection, cracks and welding residual stress are ignored. The result obtained by NLFEA method for ultimate strength in hogging and sagging are 10,83x1012 Nmm and -10,34x1012 Nmm, respectively. It is shown that the ultimate strength obtained by NLFEA is larger than Smith’s method, and the ratios of the ultimate strength comparison are 7,71% and 11,27% for hogging and sagging conditions, respectively.
Garbage Compaction Mechanism of Three-Wheels Electrical Motorcycle
Authors: Alfaroq  , Putera Andi Cahya Adi , Rahman Abdul , Muhammad Abdul Kadir , Syam Rafiuddin
Published: October 2019

This research aims to design a trash in a three-wheels electric motor with a compaction mechanism so that it can increase the volume of the trash than usual and the jack mechanism that reduces human power for waste management. This developed also includes a garbage cover with a cover mechanism that can block the smell of garbage when open or closed. The mechanism is controlled using a microcontroller and the actuator used a stepper motor. This tool has been tested using garbage and the equipment is running well.
Identification of Ground–fault Current in Various Transformer Connection and Generator Grounding using Symmetrical Components Method
Authors: Sultan A.R. , Mustafa M.W. , Saini M. , Gaffar A.
Published: October 2019

Single line to ground-fault (SLG) fault is the record frequent fault probable to occur in an electric power system. The effect of ground-fault is determined by using grounding method and transformer connections. In this study, the simulation showed the performance of a simple power system within the SLG fault in the system at various transformer connection and generator grounding method. New approach the application of ground fault current calculation using symmetrical components method on unit generator transformers. A symmetrical components method applied with simulation was conducted in Matlab software. The results were then analyzed, presenting a comparison with the fault impact at various transformer connection and generator grounding method. The models of transformer connection for each side (primary and secondary) used were wye (Y), wye-grounded (Yn) and delta (Δ). It was clearly shown that the ground-fault currents at the generator bus had significantly an effect on the type of the transformer connections used during the ground-fault at the secondary side of the transformer.
Experimental Study for Measuring Density of slag melts by An Established Archimedean Double-bob Method
Authors: Arman  , Takebe Hiromichi
Published: October 2019

The apparatus of Archimedean double-bob method for practicing accurate was established for density measurements of slag melts. The accuracy of density measurements at room temperature to establish measurements was determined in the following ways. Firstly, the densities of water were measured at 25, 30, 35, and 40 °C. Secondly, the densities of silicone fluids with the viscosities 0.01, 0.999, 4.850, and 29.44 Pa·s were measured at 25 °C. The measured densities have good agreement with the data of water standards with a precision of 0.07% and silicone fluid standards with a precision of 0.16%. The densities of Na2O–SiO2 slag melts with 60, 70 and 80 mol % SiO2 were measured in the temperature range from 1350 to 1500 °C. The density decreases with increasing temperature and increases with increasing SiO2 contents for all compositions. The reproducibility of this work is within the error estimation of density measurements. The density results of Na2O–SiO2 melts with 60, 70 and 80 mol % at 1400 °C show that the measurements data are within 0.23 % of the density values.
Investigation of Creep Behaviour of Al-9Zn-4Mg and Al-9Zn- 4Mg-5Cu Alloys
Authors: Syahid Muhammad , Sofyan Bondan T.
Published: October 2019

Two aluminium alloys, Al-9Zn-4Mg and Al-9Zn-4Mg-5Cu was prepared for candidate material impeller turbine radial inflow system Organic Rankine Cycle (ORC) that works at 130 °C. The temperature is high for aluminium alloys so the creep behaviour of the alloys have to investigated. This study identified creep resistance of the alloys and also investigated the creep mechanism of the alloys. Creep test conduct at 50 MPa and variation temperature 150, 200 and 250 °C. The fracture surface and microstructure of subsurface was examinated by SEM. The creep test result showed both of alloys did not failure at 150 °C while Al-9Zn-4Mg-5Cu has a good creep strength compare with Al-9Zn-4Mg at temperature 200 and 250 °C. The fracture surface and microstructure of subsurface indicate the coble creep mechanism or difusional creep. The good creep strength of Al-9Zn-4Mg-5Cu due to CuAl2 phase serves as a pin which inhibit the rate of diffusion at the grain boundaries.
Preliminary study on Acoustical Characteristics of Sago Midrib Composite
Authors: Kusno Asniawaty , Asriani Sherly , Kamil Kusno , Jamala Nurul
Published: October 2019

This research is a preliminary study on the use of sago midrib as an acoustic material. This study aims to determine the sago as acoustic material by measuring the absorption coefficient using (impedance tube method) of 100 Hz-1.6 KHz frequencies. The results of measurement were analyzed and compared with common acoustic material available on market as reference. From the measurement of the sago midrib composite, absorption coefficient has fluctuated from low to high frequencies as the absorption coefficient of reference material is found to be more stable.
Control of a tethered Quadrotor using a quaternion feedback
Authors: Takeuchi Ryuta , Watanabe Keigo , Nagai Isaku
Published: October 2019

In Japan, superannuation of infrastructures poses a problem and the application of unmanned aerial vehicles (UAVs) such as a Quadrotor etc. is being actively studied as one of ways of inspection. Such a Quadrotor needs any position control independent of GPS, when being used for the inspection of tunnels and of interior of building. In previous research, Ouchi et al. proposed a method for controlling the position of a Quadrotor using a tether. In addition, they derived the dynamical model of the Quadrotor considering the influence of a tether, and conducted some experiments on the attitude control. The objective of this study is to realize angle and angular velocity control in the tethered Quadrotor by applying quaternion feedback control proposed by Fresk et al. In the quaternion feedback controller, the angular velocity obtained from the gyro sensor is directly available in the controller design, so that there is a possibility that more stable attitude control can be performed. After giving the overview of the tethered Quadrotor and describing Quaternion feedback control, this paper gives some experiments to verify that it is more stable with an actual machine, compared to the conventional method.
Experimental Analysis of Smart Green House with Rotary Garden
Authors: Sutresman Onny S. , Syam Rafiuddin , Muchsin Abdul Hay , Djafar Zulkifli , Arief Syahrier , Mochtar Andi Amijoyo , Hayat Azwar , Sutresman Onny S , Amiruddin  , Radja Abdul Mufti
Published: October 2019

To overcome climate change that affects agriculture in all over the world, shows the estate and farming for the raising of the extreme weather (e.g., floods, droughts, etc). Therefore, the smart greenhouse is essential in providing sustainable food for humans. The application of Smart Greenhouse, The ultimate and most common monitored variables are temperature, moisture, the intensity of sunlight and environmental conditions to support the using of sunlight a source of electricity. This is necessary for the Smart Greenhouse to manipulates the environment in appropriate to its plant’s needs. In this case, the temperature and humidity in the greenhouse are important to keeps the productivity of the plants. So, it’s using automatic system to keep suitable environmental conditions as explained before for the plants. In this research, the smart Greenhouses is shaped Ferris wheel to make sprinkling and radiation of sunlight for plants is equally distributed for all plants and its parts, Based on the results of this experiments with rotary mechanical system for Smart Greenhouse as well shown that Smart Greenhouse can preserve suitable temperature and moisture for growing the plants.
Numerical solutions to anisotropic FGM BVPs governed by the modified Helmholtz type equation
Authors: Syam R. , Fahruddin  , Azis M. I. , Hayat A.
Published: October 2019

The Boundary Element Method (BEM) is used for obtaining solutions to anisotropic functionally graded media (FGM) boundary value problems (BVPs) governed by the modified Helmholtz type equation. A technique of transforming the variable coefficient governing equation to a constant coefficient equation is utilized for deriving a boundary integral equation. Some particular problems are considered to illustrate the application of the BEM. The results show the convergence, consistency, and accuracy of the BEM solutions.
Improving Energy Efficiency of Hybrid Beamforming System
Authors: Lee Seulgi , Lee Won-Seok , Shim Seong-Joon , Kang Tae-Hoon , Song Hyoung-Kyu
Published: October 2019

Hybrid beamforming which combines conventional digital beamforming with analog beamforming system is promising model in wireless communication. The problem is using RF chain in digital precoder spends high cost and variable phase shifter exist at analog precoder processing network. Dealing with this problem, many architectures emerge to make lower hardware complexity and power consumption. This paper proposes low-resolution solution using phase over-sampling(POS) and switches(SW) on Radio Frequency(RF) chain to improve energy efficiency. We analyze proposed POS-SW hybrid beamforming system. In the simulation, the estimate is channel capacity in different signal-to-noise and energy efficiency during increasing number of RF chain on 3 dimension(3D) channel environment. It is shown that the proposed system has almost same channel capacity and high energy efficiency compared to the conventional system.