bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of activeness lecturers in SmartLecturer based learning using fuzzy Mamdani and Sugeno
Authors: Sfenrianto Sfenrianto , Yasin Muhammad , Nainggolan Kaman , Yel Mesra Betty
Published: January 2020

The success of learning in a classroom that uses supporting media demands lecturer activity. The level of activity of lecturers in class and using learning media such as Smart lecturer can be measured using a fuzzy logic approach. This study aims to measure the level of active lecturers using the approach, namely: Mamdani and Sugeno method. Stages of lecturer activity measurement by forming a fuzzy set, composition rules as many as 24 rules and the defuzzification process using the centroid method that produces the level of activity of each is low, medium and high. Based on 173 lecturer activity data, the results of the Mamdani method indicates low 66%, medium 31%, and high 3%. While the Sugeno method produces a level of activity low 75%, moderate 17%, and high 8%. Therefore, Mamdani method is more suitable for the calculation because the spread of results is relatively evenly distributed at each level.
Estimations of Indonesian poor people as poverty reduction efforts facing industrial revolution 4.0
Authors: Wanto Anjar , Hardinata Jaya Tata
Published: January 2020

Indonesia is one of the developing countries that have serious problems with poverty. The still many poor people in Indonesia encourage the government to make and determine the right policies so that the problem of poverty can be overcome and not drag on. Therefore, the authors conducted this study to try to help the government conduct an analysis in predicting the level of development of the poor in Indonesia. The prediction method used is the Bayesian Regulation artificial neural network. This method is a development of the backpropagation method that is often used to predict data. The data used are data on poor people in Indonesia in 2012-2018, which are sourced from the Indonesian Central Bureau of Statistics. Based on this data a network architecture model will be formed and determined using the Bayesian Regulation method, including 10-5-10-2, 10-10-10-2, 10-10-15-2, 10-10-20-2, 10-15-10-2, 10-15-15-2, 10-15-20-2, 10-20-20-2, 10-25-25-2 and 10-30-30-2. From these 10 models after training and testing, the results show that the best architectural model is 10-25-25-2. The accuracy of the architectural models is 94.1% and 61.8% with MSE values of 0,00013571 and 0,00005189. The results of this study are the prediction of the poor for the next 5 years.
Improving the accuracy of old and young face detection in the template matching method with Fuzzy Associative Memory (FAM)
Authors: Sembiring Rafika Sari , Efendi Syahril , Suwilo Saib
Published: January 2020

Every human has a face pattern and certain characteristics even though identical twins, but the human face pattern still has its own distinctiveness as well as old face patterns and young face patterns even though the human face pattern is very diverse but for young and old face patterns will be a difference between one face and the other face. Face detection (face detection) is one of the initial stages that very important in face recognition that is used in biometric identification. Face detection can also be used to search or index face data from images or videos that contain faces of various sizes, positions, and backgrounds. Face detection (face detection) automatically with the help of a computer is a problem that is not easy because the human face has a high level of variability both intra-personal and extra-personal variability. This study shows that systems with template matching methods combined with FAM can successfully detect differences in human faces, 80% accuracy, 10% better by using ordinary template matching.
Modification of variably modified permutation composition (vmpc) algorithm genetic key algorithm for data security
Authors: Ompusunggu E S , sawaluddin  , Nababan E B
Published: January 2020

Cryptography is the study of mathematical techniques related to information security aspects such as validity, data integrity, and data authentication. In this study, Variably Modified Permutation Composition (VMPC) algorithm is modified by adding complementary methods to the encryption and decryption process. Keys that are generated randomly will be optimized using Genetic Algorithm. The Variably Modified Permutation Composition (VMPC) algorithm is a symmetrical stream cipher algorithm similar to the RC4 cipher designed by Bartosz Zoltak. The Variably Modified Permutation Composition (VMPC) algorithm is an extension of the one-way function VMPC that was developed into a byte-based encryption algorithm. In its use the VMPC is generated by an 8-bit stream of 256 element permutations. The initial state of the permutation is calculated in VMPC Key Scheduling. The Genetic Algorithm produces a unique intermediate key for each algorithm run. The intermediary key is combined with the Ciphertext in the first level which produces the second level Ciphertext, up to the third level Ciphertext. Attackers will not be able to carry out attacks such as brute force, differential attacks or statistical attacks without having knowledge of the key. From the results of the tests carried out, the more characters that are encrypted and decrypted, the longer it will take. On testing the avalanche effect produces an average value of 51.25% for keys without optimization while 53.42% for keys optimized. The effect of key optimization using Genetic Algorithm has increased the value of the avalanche effect and has an effect on the results of changing bits in the ciphertext.
Increased accuracy in the classification method of backpropagation neural network using principal component analysis
Authors: Sitompul Kristin Lorensi , Zarlis Muhammad , Sihombing Poltak
Published: January 2020

Water and air in life are needed in every human and living creature on earth, especially with the status of water quality and air quality status that must be known to humans. Water and air quality status has 120 records with 8 attributes consisting of 4 classes and 1096 records with 5 attributes consisting of 6 classes. Water and air quality classification can affect performance in data grouping. So from that the author tries to increase accuracy in classification by using the Neural Network Backpropagation algorithm with PCA. In this study, it is expected that the Backpropagation Neural Network algorithm using PCA is able to increase accuracy in the classification method.
Analysis of RSA variants in securing message
Authors: Nasution Nadia Widari , Efendi Syahril , Sawaluddin
Published: January 2020

Message security is an important thing to prevent the interference from third parties. RSA cryptographic algorithm is believed to be a powerful algorithm in securing message. However, RSA computing process takes a long time so it takes several variants of RSA, namely R prime RSA and Multi-factor RSA which can reduce time and computing cost on the encryption and decryption side. In this paper, the author use three prime numbers to improve better security than only use two prime numbers and minimize the value of private key “d” is by using Chinese Reminder Theorm (CRT).
Effect of inventory turnover on the level of profitability
Authors: Nasution Abdillah Arif
Published: January 2020

This study aims to determine the effect of inventory turnover on profitability in automotive companies listed on Indonesia stock Exchange from 2015-2017. Profitability is measured by Return On Assets (ROA). The data used are the financial statements of each sample company, which are obtained through ICMD (Indonesia Capital Market Directory) The analytical method used in this study is a quantitative method, by testing classical assumptions, as well as statistical analysis, namely simple linear regression analysis. The sampling method used is purposive sampling. The variables of this study are inventory turnover as variable X, and Return On Assets as Y variables with a total sample per year of 18 companies. The results of this study are inventory turnover does not have a positive effect on Return On Assets.
Analysis of waveguide with special resonant window which can reduce the energy consumption of waste rubber pyrolysis
Authors: Liu Qiangcai , Su Xin , Hu Lihao , Zhao Xianbing , Li Zhihua
Published: January 2020

Microwave pyrolysis is a new technology for waste rubber treatment. In this paper, the microwave energy transfer characteristic working at a frequency of 2.45 GHz in different types of rectangular waveguides are investigated with HFSS simulation software. The results show that although the quartz sealing plate of the rectangular waveguide can prevent the combustible gas generated by waste rubber pyrolysis from entering the microwave generator, it also causes some microwave reflection at the same time, which will reduce the microwave energy transmission efficiency, shorten the service life of the microwave generator. While the resonant window of the rectangular waveguide, that is, a rectangular window with a certain size in the centre of the copper sealing plate, and with a quartz plate embedded in the window, can avoid such microwave reflection, not only enhance the sealing performance, but also improve the waste rubber pyrolysis efficiency and reduce the pyrolysis energy consumption.
Nano layered-spinel 0.8Li2MnO3 · 0.2LiMn2O4 as high-performance cathode for Li-ion batteries
Authors: Zhu Zhenye , Zhuo Sang
Published: January 2020

The nano layered-spinel 0.8Li2MnO3·0.2LiMn2O4 cathode material has been synthesized by a simple solvothermal method. X-ray diffraction studies show that the as-prepared material has two compositions, including Li2MnO3 and LiMn2O4. Moreover, the surface morphology of the precursor and cathode material were characterized by scanning electron microscopy. Meanwhile, the EDS graph reflects homogeneous mixing of the two compositions due to the novel precursor synthesizing method. Consequently, as a cathode material for LIBs, the resulting nano layered-spinel 0.8Li2MnO3·0.2LiMn2O4 achieves a high discharge capacity of 248 mA h g−1 at 25 mA g−1 and 162 mA h g−1 even at 1250 mA g−1. In addition, the cathode material shows a high reversible capability with 180 mA h g−1 after 50 cycles, which delivers medium cycling performance.
Used of bottom ash waste from power plant and tailing as mine backfill
Authors: Masniyom M , Jaiboon W
Published: January 2020

The using of bottom ash and tailing were by product from Mae Moh coal fired power plant as mine backfill. Laboratory was investigated the chemical, physical and mechanical properties of backfill containing bottom ash, tailing and cement. Using cast of backfill materials to test the ability of compressive strength in box size 5×5×5 cm. Four different types of backfill that portland cement type 1 was replaced by bottom ash, in the proportion of percent 5, 10, 15 and 20 by weight uncured and cured in water for 7 and 28 days. Backfill materials characterization bottom ash have been examined in grain size distribution, chemical composition analyzed by X-ray fluorescence (XRF) of backfill material. For the mechanical property was test by uniaxial compressive strength machine. The result was found that mixing ratio of bottom ash can be used as backfill material ranging from 15-20 % by weight. The mechanical property of backfill mixture suitable for use with compressive strength from 6.4-19.7 MPa and cured in water 28 days was maximum compressive strength.
Experimental research on sound absorption properties of impedance gradient composite with multiphase
Authors: Liu R X , Pei D L , Wang Y R
Published: January 2020

In order to improve the sound absorption performance of the sound absorbing material in water, impedance gradient underwater sound absorbing composite with multiphase (IGCM) is prepared in this study. By superposing several layer materials of different impedance gradients, the mixture is poured in the mold layer by layer so that three kinds of IGCM with different mass density gradients of iron powder, tungsten powder and mixture of iron powder and tungsten powder are prepared. Under two operating conditions of the incident angle of 0°and 20°, the results show that the three IGCMs have good broadband absorption characteristics. The sound absorption frequency ranges of the three samples of IGCM under normal incident conditions are concentrated between 6kHz and 10kHz. The sound absorption performance of IGCM under oblique incidence is better than that under normal incidence, especially the IGCM with iron-tungsten powder, which could achieve wide-band strong sound absorption from 2kHz to 10kHz under the condition of oblique incident. The IGCM with iron-tungsten phase under sound wave’s incident angle of 20 ° exhibits better sound absorption performance than the other two, which provides a theoretical reference for the design and manufacture of gradient sound absorbing materials.
Influence of welding groove on residual stress and distortion in T-joint weld
Authors: Wei Chong Yi , Jiang WenGuang
Published: January 2020

T-joint welding is the most common type used in heavy equipment industry. Localized heating and subsequent cooling induce residual stress in the weld process. Service loading overlapped with residual stress influences the strength of the welded structure and leads to premature failure of structure. In this study, finite element analysis is used to study the influence of welding groove on residual stress and distortion in T-joint welding. The simulation consists of sequentially coupled thermal and elastic-plastic analysis using an element birth and death method to model the addition of weld metal to the workpiece. The results of numerical simulation are verified by comparing with experiment from published literature. The results show that welding groove has a significant influence on welding residual stress.
Effect of Ca/K Modified ZSM-5 on Catalytic Cracking of Low Carbon Olefin
Authors: Liu Xiaohua , Huang Wenqing , Man Yi , Wang Dingbo , Jiang Jianzhun
Published: January 2020

In this paper, the structural and acidic changes of ZSM-5 zeolite modified by K and Ca were studied. Meanwhile we use in-situ FTIR to study the reaction of isobutylene on ZSM-5 zeolite before and after modification, investigating reaction mechanism and optimal reaction time. The results shows that the amount of weak acid increases in the modified zeolite. The Ca-ZSM-5 can not only effectively control the hydrogen transfer reaction to inhibit the formation of aromatic hydrocarbons, but also promote the occurrence of dehydrogenation cracking reaction; while the K-ZSM-5 is not effective in the cracking reaction.
Study of the Dielectric Properties of Condenser Material Used in SF6 Insulated RIP Bushing
Authors: Shiling Zhang
Published: January 2020

All In the frequency range of 10−1∼106Hz and the temperature range of -100∼200°C, the experimental dielectric spectrum of the condenser material used in UHVDC RIP bushing has been measured by Novocontrol broadband dielectric spectroscopy. The measured data has been fitted applied to nonlinear numerical calculation of the Havriliak-Negami (HN) equation, by which the characteristic parameters of HN mathematical model have been got. The studies show that the genetic algorithm combining with the least-square curve fitting method can ensure the uniqueness and accuracy of the fitting parameters. In the frequency range of 10−1∼106Hz and the temperature range of -40∼60°C, β relaxation process mainly takes place in the condenser material. In temperature range of 70∼150°C, α and β relaxation processes can be observed. In the temperature range of 160∼200°C, the α relaxation and DC conduction processes are obvious. The DC conductivity and relaxation time have significant temperature dependence which can be fitted well with Arrhenius equation.
The design of swirl burner in a pulverized coal gasifier by numerical analysis
Authors: Dachuan Qin , Bing Li , Mingquan Wang , Chao Yang
Published: January 2020

In this paper, the eddy-dissipation-concept model is used to simulate the influence of burners of different structures on the performance of gasifier. The effects of the annular inner and outer passage, annular air passage and annular pulverized coal passage on the spatial distribution of flow field, temperature field and grouping field in gasifier were investigated. The simulation results show that pulverized coal can obtain higher carbon conversion rate by going through the annular outer passage of the burner. As the number of air swirl S increases, the high temperature flame in the gasifier becomes more dispersive and the temperature gradient becomes smaller. The high temperature flame zone in the gasifier is more diffuse when pulverized coal goes through the annular outer channel than the annular inner channel, which can reduce the temperature of the high-temperature flame zone.
Layers obtained on TiCN aluminum nanocomposites by electron-beam treatment
Authors: Lazarova R , Valkov S , Dyakova V , Petrov P
Published: January 2020

The impact of electron beam treatment on aluminum composites containing 0, 2, 5 and 10 wt. % TiCN nanoparticles was studied. Aluminum nanocomposites were produced as rods with 12 mm diameter by means of preliminary cold volume compression and succeeding hot pressing. Cylinders with a height of 10mm were cut from the rods and their flat surfaces treated by scanning electron beam techniques. The electron-beam treatment (EBT) process was carried out using Leybold Heraeus (EWS 300/15–60) electron beam equipment. Two technological regimes were used: with low energy power input Q1 and with high energy power input Q2. Composite layers with a strong bond to the substrate were obtained. Light microscopy (LM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used for characterizing the microstructure. The phase composition of the obtained specimens was studied by means of X-ray diffraction (XRD) using CuKa characteristic radiation (λ=1.54 Å). The microhardness was discussed with respect to the applied technological conditions of the EBT and corresponding microstructure and crystallographic structure of the formed layers. Nanocomposite layers with improved hardness were obtained which is necessary as exploitation surface properties of automobile and aircraft parts. It was found out that the microhardness of samples treated with high energy was much lower than the one of the samples treated with low energy. The strengthening mechanism in the samples was discussed.
A monolithic integration scheme for GaN-based power converter integrated circuit using fully-Schottky versatile HEMTs
Authors: Wang Zeheng , Luo Yi , Chen Chao , Chen Zhanzhuang , Feng Xuewei , Yao Yuanzhe
Published: January 2020

A monolithic integration scheme for GaN-based power converter integrated circuit is proposed in this paper, wherein the scheme is based on a novel versatile HEMT architecture featuring full-Schottky contacts. By simply introducing only one type of device for building both field effect transistors and diodes, the power converter ICs could be realized in a compact way. In addition, this scheme avoids harmful high temperature process which is for forming ohmic contacts in some nitride semiconductors. In this sense, this scheme could significantly reduce the complexity of the integration, and therefore, promisingly enable higher device performance.
Construction of high sensitivity non-enzymatic glucose sensor based on three-dimensiona nickel foam supported Ni2P/NiO/CeO2 nanoflake arrays
Authors: Qin Yongqiang , Wang Yan , Yu Cuiping , Cui Jiewu , Yu Dongbo , Wu Yucheng
Published: January 2020

Three-dimensional (3D) nickel foam supported Ni2P/NiO/CeO2 nanoflake arrays (NFAs) were synthesized by hydrothermal, anneal and low-temperature phosphatizing processes. As-prepared samples were systematically researched by SEM, XRD, XPS, TEM, EDS and HRTEM technology. Cyclic Voltammgrams and Chronoamperometry technology were used to measure the sensors performance of Ni2P/NiO/CeO2 NFAs. The results indicated that non-enzymatic glucose sensors based on Ni2P/NiO/CeO2 NFAs exhibited a high sensitivity of 28.23 mA cm−2 mM−1 and good anti-interference ability, suggesting that the 3D nickel foam supported Ni2P/NiO/CeO2 NFAs as a non-enzymatic glucose sensor is promising for practical applications.
Study on Preparation of Microlens Array Hydrophobic Flim by Ultraviolet Curing Micro-imprint
Authors: Jiajia Wang , Jianyun He , Zengqiang Shen , Xu Ma , Weimin Yang
Published: January 2020

In this paper, the formation process of microstructure array hydrophobic film prepared by ultraviolet curing imprinting was studied. The UV-curing micro-imprinting method was used to replace the traditional hot stamping method to prepare the micro-structured hydrophobic film. The effects of illumination time and intensity on the surface hydrophobicity were investigated.Results shown that the micro-structure hydrophobic film prepared by UV-curing micro-imprint has high replication precision and good hydrophobic effect. With the increase of illumination time, the water contact angle of the product increased and reached to 125° at 30s illumination time. With the increase of the illumination intensity, the water contact angle of the micro-imprinted product was also gradually increased.
Synthesis and characterization of a luminescence podand bridged dipyridyl platinum(II) complex
Authors: Zheng Xiaorui , Mao Ming-Zhen , Huang Xiao-ying , Wang Lieping , Ning Binke
Published: January 2020

We have designed and synthesized an aromatic podand containing two dipyridyl plantinum complexes in both ends of the podand, of which the luminescence in solution is reversibly fabricated by adding equal equivalent of dibenzylammonium hexafluorophosphate and base. The results are obtained by absorption and emission spectroscopy and 1H NMR spectroscopy.
Influencing factors and experimental study on performance of composite cement-based grouting
Authors: Du Tianling , Liu Ying
Published: January 2020

The performance of grouting material directly affects the grouting effect under cement concrete pavement slab. In this paper. the factors affecting the fluidity, strength and bleeding rate of grouting materials are analysed by repeated tests. The test results show that the slurry with good suspension is not easy to be diluted by water and has certain waterproof performance; The water-cement ratio is in the range of 0.35 to 0.5, and the suspension is good and not easily separated; Incorporation of fly ash will cause early strength reduction and increase of slurry bleeding. It is recommended not to exceed 50% of cement. Finally,it is suggested that the strength of the grout should not be as high as possible, and the problem of strength development at the late stage of grouting and matching of the strength of the base layer should be fully considered.
Experimental study on the bonding of microfluidic chip
Authors: Jinghui Zhang , Jianyun He , Xidan Luo , Jinge Tong , Xu Ma , Weimin Yang
Published: January 2020

In this paper, the ultraviolet radiation curing technology is applied to the processing and manufacturing of microfluidic chips, and a new method of irradiation bonding of photocuring microfluidic chips is studied. Research has shown that by photocuring bonding method, the bonding strength of the photocuring microfluidic chip is high, the bonding speed is fast, the efficiency is high, and since the auxiliary solvent such as adhesive is not needed, the microchannel is not polluted, and the permanent bonding is realized. This new method of photocuring bonding has effectively solved the bonding problem of the microfluidic chip and the photocuring bonding strength satisfies the application requirements.
Effect of the in-situ polymerized polyurethane on laminated epoxy adhesive / aramid fabrics composites
Authors: Guang Lei Lv , Rui He
Published: January 2020

In order to avoid the high brittleness of epoxy resin and the low peeling strength of its laminated composite, polyurethane was synthesized by in-situ polymerization in epoxy adhesive system. The results of IR, SEM and mechanical properties test showed that the peel strength and shear strength of laminated epoxy adhesive / aramid fabrics composites reached the optimum value when the molar ratio of NCO/OH was 1.2, the content of MoCA curing agent was 1.5% and the content of polyurethane prepolymer was 20%. The brittleness of epoxy resin was reduced to a certain degree, and the bonding properties of epoxy adhesive/aramid fabrics composites were improved.
First-principles investigations of structural, elastic, thermodynamic and electronic properties of Pt3Hf compound under pressure
Authors: Li Zongbo , Xiong Kai , Sun Yingjie , Chen Xiuhua , He Junjie , Zhang Shunmeng , Fu Yingjie , Mao Yong
Published: January 2020

The pressure effects on the structure, elasticity, thermodynamics and electronic properties of Pt3Hf compounds were investigated by first-principles calculations based on density functional theory. The obtained equilibrium lattice parameter is consistent with the experimental and theoretical values. The calculation results show that the elastic constants, bulk modulus, shear modulus, Young modulus, anisotropy factor and Debye temperature, sound velocities increase with the increase of pressure. The B/G ratio and Poisson’s ratio results show an upward trend with increasing pressure, which means that increasing external pressure can enhance the ductility of Pt3Hf compound. Analyzing the charge density difference and the density of states reveal that charge accumulation gradually increases with the increase of pressure between Pt and Hf atoms.
Elastic Modulus Prediction of Particle Reinforced Composites Based on Sphere Model
Authors: Li Yanru , Jiang Haibo
Published: January 2020

The elastic modulus calculation of particle-reinforced composites is a classic but rather complex issue. By adopting analytic method, this paper is intended to seek solutions and calculations with the help of the symbolic integral operation function of the software Mathematica to derive the analytical expressions of the elastic modulus of particle-reinforced composites. Study shows that the representative volume unit of particle-reinforced composites may be expressed with spherical model. Two calculation methods which feature “first parallel and then serial” and “first serial and then parallel” respectively deliver two slightly different elastic modulus values, and the intermediate value may be deemed as the predicted elastic
Simulation of Giesekus fluid flow in extruder using helical coordinate system
Authors: Vachagina E K , Kadyirov A I , Karaeva J V
Published: January 2020

In the present work, it is proposed to use a helical coordinate system for mathematical modeling of non-isothermal Giesekus fluid flow in the extruder in the metric zone. The convenience of using a helical coordinate system is to reduce the three-dimensional problem to two-dimensional without the use of additional assumptions. The helical coordinate system is applicable only for steady flow conditions. Particular results of the numerical implementation of the use of a helical coordinate system are presented on the example of a Giesekus fluid flow in an extruder with a single flight, the results are compared with the flow of Newtonian fluid.
Temperature effect on the Production of Highly charged Fe Ion beams at 14.5 GHz ECR Ion source
Authors: Liu H. P. , Li J.Y. , Kang L. , Zhang T. M. , Li J.
Published: January 2020

Temperature is one of the important parameters that effect the production of metal ion using MIVOC method. Beams of highly charged iron ions are produced with 14.5 GHz all-permanent-magnet electron cyclotron resonance ion source at three temperatures at 320 kV high voltage multi-discipline platforms for highly charged ions at IMP, CAS. At 18 °C, Fe13+ and Fe15+ of more than 15.9 eμA and 11.7 eμA have been extracted with an extraction voltage of 15 kV and a microwave power of 300 W. When increasing temperature to 25 #x00B0;C and 30 #x00B0;C, more main substance arrives at the plasma chamber of ion source and the outputs of Fe15+ and Fe16+ decreases, but those of Fe13+, Fe12+ and Fe11+ increase, the distribution of Fe ions shifts towards low charge state. The conductance of the coupled MIVOC system is estimated at different temperatures. The ionization efficiencies and the effective consumptions rate of ferrocene are also figured out from the vapour pressure and the intensities of iron ion beams. With the increase of the temperature, the conductance and the consumptions increases while the dependence of ionization efficiency on the temperature is different.
Colorless, heat resistant polyimide films derived from 2,3,3′,4′-biphenyltetracarboxylic dianhydride
Authors: Song G , Chen C
Published: January 2020

The development of high performance colorless polyimide (PI) films is one of the targets of PI chemistry, since heat resistant colorless PI films are key materials for reliable plastic substrates in image display devices. In the present work, 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) was used to polymerize with diamines to afford a series of PI, as shown in Scheme 1. Due to the fully aromatic composition, the films displayed high thermal decomposition temperatures (T5%). PI-FDA and PI-FFDA had similar glass transition temperatures (Tg) around 425°C, and much higher than that of PI-TFMB. PI-TFMB and PI-FFDA showed a transparent and colorless feature, with high transparency at 400nm (T400). Coefficients of thermal expansion (CTE) were found around 55ppm.°C−1 for the series of PI films, larger than the requirement of flexible substrate applications, which could be attributed to the distorted chain structure derived from the a-BPDA component.
Preparation and luminescence of rare earth complex Eu(DBM)3(TPPO)
Authors: Li Q Y , Tang P S , Shen W B , Zhou Y F , Niu Z R , Wang Y L , Ding Y B
Published: January 2020

Using Eu2O3 as source of europium, anhydrous ethanol as solvent system, methylene benzoyl(DBM) as first ligands, triphenyl phosphine (TPPO) as second ligands, the europium(III) ternary rare earth complex Eu(DBM)3TPPO has been successfully prepared. The samples were characterized by fluorescence spectrum(FS), Fourier transform infrared spectroscopy(FT-IR), thermogravimetry differential scanning calorimetry(TG-DS) and scanning electron microscope(SEM). The influence of TPPO on luminescence intensity, color temperature, color coordinates, morphology and thermal stability of the samples were analyzed. The results showed that the addition of second ligand could enhance the luminescence intensity of Eu(DBM)3TPPO. Eu(DBM)3TPPO can emit strong red fluorescence when excited by 395nm ultraviolet light. The color coordinate of Eu(DBM)3(TPPO) is (0.63, 0.36). The Eu(DBM)3TPPO is a kind of red luminescent material with wide application prospect.
Lightweight optimization design of arm frame for aerial work platform based on NSGA-II algorithm
Authors: Wang Zhiyong , Liu Xiping
Published: January 2020

In the previous lightweight design of the arm of aerial work platform, it is difficult to balance the relationship between lightweight and stiffness reduction. This paper proposes a lightweight design that minimizes the variation stiffness while reducing weight. Taking the arm mass and stiffness variation as the objective, which constrained by yield strength and stiffness of the material, the Pareto front of each arm section size is obtained by the second generation of elite strategy non-dominated sequencing genetic algorithm (NSGA-II). Finally, the finite element model is established by ANSYS to compare the static and dynamic performance of the arm before and after optimization. The results show that the weight of the optimized arm is reduced by the original 13.3%, lightweight effect is remarkable.
Preparation and Characterization of Tetraphenylporphyrin Dyes
Authors: Li Xinhui
Published: January 2020

Porphyrin compounds exist widely in nature and are a key part of photosynthesis and photosynthesis. Because of its good photothermal stability and many unique physical and chemical properties, it has been widely used in the research and development of sensitized dye solar cells. As a new type of solar cell, dye-sensitized solar cell has attracted extensive attention and research due to its simple manufacturing process, relatively cheap price, high photoelectric conversion efficiency and environmental protection. In this paper, control experiments were carried out to synthesize tetrabenzoporphyrin with higher yield and purity by changing the solvent and washing solvent. The samples were characterized by uv-vis spectra. The results showed that the tetraphenylporphyrin crystals with better comprehensive effect could be obtained by using ethanol solution as sample solution and distilled water as washing solvent.
Preparation of TAT tri-layer insulating film on automotive glass using magnetron sputtering method
Authors: Chen Yifan
Published: January 2020

In this paper, tri-layer structured films of titanium dioxide, silver and titanium dioxide were deposited on ordinary glass using radio frequency magnetron sputtering method to serve as thermal insulation films on automotive glass. The transmittance and thermal insulation of the prepared insulating films were changed by altering the deposition time of silver and titanium dioxide. The transmittance, absorbance and thermal insulation of the insulating films to visible light and infrared light were measured by ultraviolet-visible spectrophotometer and infrared spectrometer. The thermal conductivity of the films with different transmittances was tested by the thermal conductivity tester. The insulating films with lower thermal conductivity were screened out for analysis, and on this basis, the experiment was improved continuously. The total solar energy rejection rate was calculated subsequently. After summarizing the whole experiment process, the improvement measures were put forward to optimize the production of insulation films on automotive glass. The results show that the transmittance of TiO2-Ag-TiO2 tri-layer insulation film is 70.19%, and the solar energy rejection rate is 67.80%. The transmittance meets the national standard and the total rejection rate is also higher than many of the insulation films on the market.
Designing Cor–Shell Materials Using Humic Acids
Authors: Skripkina T S , Podgorbunskikh E M , Lomovsky O I
Published: January 2020

Due to the high content of complexing moieties, humic acids are promising compounds for designing heavy metal sorbents that can be used in natural environment objects. Experiments focused on designing sorbent particles containing a humic shell and a core (that is supposed to impart the desired performance characteristics to the particle) and applying humic acids onto various materials were conducted. It is demonstrated that the sorbent with a “lignocellulosic core–humic shell” structure can be produced mechanochemically. The efficiency of humic acid binding to lignocellulosic materials directly correlates with lignin content within lignocellulosic materials. A method for passing lignin from the surface of lignocellulosic biomass into the solution using humic acids is found. Unmodified highly lignified biomass is the optimal material for applying humic acids onto lignocellulosic materials.
Scaling up the Mechanochemical Technology for Producing Materials Enriched in Humic Acids
Authors: Skripkina T S , Bychkov A L , Rozhanskaya O A , Lomovsky O I
Published: January 2020

Mechanochemical treatment is widely used in industry as it allows one to reduce the number of processing stages, either reduce or completely eliminate the use of solvents, automate the technology and ensure its mobility. Energy input is an important parameter of mechanochemical treatment. In this study, the technology of mechanochemical oxidation of brown coal was scaled up using the planetary mills of AGO-2 and APF types, as well as K-7 and CEM-20 flow-type vibrocentrifugal mills. The technology of mechanochemical oxidation of brown coal makes it possible to increase the availability of humic acids in brown coal and the content of oxygen-bearing groups capable of complexation, as well as to improve sorption characteristics of the resulting product. Materials enriched in humic acids can be used as heavy metal sorbents in water bodies and as agents for soil amelioration. The rotor speed of 1400 rpm and the feed rates of 15 kg/h and 1.8 kg/h for CEM-20 and for K-7 vibrocentrifugal mills, respectively, are the optimal modes from the point of view of chemical and economic efficiency. These modes increase the yields of alkali-soluble and water-soluble humic acids from 23 to 59 % and from <1 to 7%, respectively, which corresponds to the values reached using the laboratory-scale equipment.
Modification of Manila Grass Activated Carbon for Reactive Dye Adsorption from Textile Printing Wastewater
Authors: Charnkeitkong P , Phoophuangpairoj R
Published: January 2020

The aim of this research is to focus on the activated carbon modification for the elimination of Novacron Brilliant Red EC-3GL which is a reactive red dye onto Manila Grass carbonaceous as an adsorbent with chemical activation. The Manila grass waste from the football field was obtained to carbonize at 400 °C. Three-types of chemicals, such as sodium chloride (NaCl), potassium hydroxide (KOH), and phosphoric acid (H3PO4) were used to soak for 1 h before pyrolysis at 700 °C for 2 h. The analysis of activated carbon properties and effects of dye adsorption, such as pH of the feed solution, time to adsorb, the amount of adsorbent, concentration and temperature were studied. Langmuir isotherm and Freundlich isotherm were applied to consider the adsorption mechanism. From the analysis, activated carbon with sodium chloride activation was a high surface area of 148.6 m2/g and a low porosity of 25.72 °A. From the experiments were found that pH for adsorption of 2, absorption time 90 minutes, concentrations used in the adsorption of 50 ppm and the adsorption temperature 30 °C were optimum for dye adsorption. The NBR adsorption percentages from aqueous solution and textile printing wastewater were 77.87 and 85.52, respectively. The adsorption mechanisms of activated carbon were consistent with Langmuir isotherm for an aqueous solution and Freundlich for textile printing wastewater.
Thermoelectric properties of poly (3,4-ethylenedioxy thiophene)/poly (sulfonic acid diphenyl aniline) composites synthesized in the absence and presence of magnetic field
Authors: Ugraskan Volkan , Karaman Ferdane
Published: January 2020

Poly(3,4-ethylenedioxy thiophene)/polysulfonic diphenyl aniline (PEDOT:PSDA) composites in the ratios of 1:0.5, 1:1, 1:1.5 and 1:2 were synthesized by oxidative chemical polymerization in the absence and presence of external constant magnetic field which the flux density is 3 kGa. The samples were characterized by UV–vis, FTIR-ATR and XRD. Their thermoelectric properties were obtained by means of electrical conductivities and Seebeck coefficients measurements. It was found that both the conductivity and Seebeck coefficients of the PEDOT:PSDA composites were increased in the presence of magnetic field. The conductivities of PEDOT:PSDA composites are lower whereas their Seebeck coefficients are considerably higher than that of commercial PEDOT:PSS. The highest power factor was obtained as 32 μW m-1K−2 for the composite PEDOTPSDA = 1:1 synthesized in the presence of magnetic field. The power factor of this sample was enhanced to 185 μW m-1K−2 by a secondary doping with sodium dodecyl benzene sulfonate.
Facile in-situ synthesis of 2D/3D g-C3N4/Cu2O heterojunction for high-performance photocatalytic dye degradation
Authors: Si Ying , Zhang Xiaoxian , Liang Tingting , Xu Xun , Qiu Lingfang , Li Ping , Duo Shuwang
Published: January 2020

Constructing heterojunction is a promising method to enhance visible-light utility and promote photogenerated e−-h+ pairs separation of g-C3N4. Herein, the present work reported a g-C3N4/Cu2O heterojunction by a facile in situ synthetic strategy. The structure, morphology, optical, electrochemical and photocatalytic properties were investigated. The results showed the combination of g-C3N4 nanosheets and Cu2O nanospheres resulted in the close contact interface and wide visible-light response range, and fast separation of the photo-generated e−-h+ pairs. The pristine g-C3N4 showed weak photocatalytic performance towards methyl orange (MO) under visible-light irradiation, compared with pristine g-C3N4, the photocatalytic degradation rate of optimized g-C3N4/Cu2O composite demonstrates the substantially enhanced photocatalytic activity, which showed no obvious loss after five repeated use. The enhanced performance was ascribed to the synergistic effect of good visible-light harvesting and enhanced separation rate of the charge carriers.
In-situ one pot synthesis of graphene-ZnO nanohybrid and its application to UV light detection
Authors: Rattan Sonal , Kumar Suresh , Goswamy J K
Published: January 2020

The development of molecular/nanoscale level assemblies allows the foundation of many potential novel applications. Chemical approach is one of the most favoured techniques to manipulate the nano-materials in a controllable manner. Herein, we report a simple and reliable one pot technique for preparing graphene-ZnO nanohybrid by coordinating zinc metal ions from precursor, which further led to the growth of ZnO nanoparticles on graphene sheets. The developed heterostructures were characterized through X-ray diffractometry, Fourier transformed infra-red (FTIR) spectroscopy, UV-visible spectroscopy and field emission scanning electron microscopy (FESEM). Morphological details revealed the dense loading of ZnO nanoparticles onto the surface of graphene. The nanohybrid was found to be electrically more responsive to the incident UV light compared to ZnO nanoparticles alone. The proposed method can lead to the fabrication of highly sensitive flexible light detector.
Optical characterization of photocatalytic copper doped thin films of anodized titanium
Authors: Rotich Julia , Mwamburi Mghendi , Walter Njoroge , Maghanga Christopher , Munyati Onesmus , Hatwaambo Sylvester
Published: January 2020

Titanium oxide is used in a myriad of applications such as in capacitors, insulation paints among others. It is a prime candidate for water splitting due to its photocatalytic properties. In this work, undoped TiO2 thin films were prepared by anodizing titanium foils cut into pieces measuring 60 mm by 20 mm. The specimens were anodized in an electrolyte consisting of 0.5 M H2SO4 and 0.075% wt HF at room temperature. The anodizing voltages ranged from 50 V to 100 V. Anion doping of copper in as anodized TiO2 was done electrochemically. The as anodized Ti foils were dipped in a 1 M Cu2SO4 solution. All samples were annealed at 450 °C for 3 h. Near-normal total reflectance was measured on as anodized and copper pigmented samples in the solar (300–2500 nm) wavelength range. Spectrophotometric reflectance data was analyzed to obtain the absorption coefficient and using the same to determine the band gap of the films. It was noted that the films exhibited reduced solar integrated reflectance for TiO2 samples prepared at lower anodic voltages of 50, 60 and 70 V. The copper pigmented, and annealed, TiO2 samples exhibited both direct and indirect energy band gaps in the ranges, 3.38–3.86 and 2.50–2.74, respectively. Further, annealing and copper doping of the films lead to increased absorption. The photocatalytic activity of the films was assessed by measuring the rate of degradation of 10ppm methylene blue in UV light source. Copper doped TiO2 exhibited enhanced photocatalytic performance in compared to pure TiO2. An increase in the anodization voltage caused subsequent increase in photocatalytic activity of films with 70 V as the optimum voltage above which photo degradation of methylene blue decreased.
Effect of friction stir processing and hybrid reinforcement on wear behaviour of AA6082 alloy composite
Authors: Satish Kumar T , Shalini S , Krishna Kumar K
Published: January 2020

In the present study, microstructure, mechanical properties and wear behaviour of AA6082 alloy reinforced with Yttrium oxide (Y2O3) and graphite (Gr) surface hybrid composites produced via friction stir processing have been investigated. Vol.% of Y2O3 particles was varied (2, 4 and 6 vol.%) while the graphite content was kept at as 4 vol.%. Microstructure of synthesized composites revealed uniform distribution of Y2O3 + Gr particles accompanied by a significant reduction in grain size. Microhardness of the composites was found to be 40% higher than the matrix alloy and tensile strength of the composites increased with increase in vol.% of Y2O3 with a marginal decrease in ductility. Wear test results along with SEM micrographs of worn out surface of composites and matrix alloy were compared and correlated with their hardness. Hybrid composites showed better wear resistance.
The synergistic effect of biosynthesized silver nanoparticles from a combined extract of parsley, corn silk, and gum arabic: in vivo antioxidant, anti-inflammatory and antimicrobial activities
Authors: Helmy Aya , El-Shazly Mohamed , Seleem Amany , Abdelmohsen Usama , Salem M Alaraby , Samir Ahmed , Rabeh Mohamed , Elshamy Ali , Singab Abdel Nasser B
Published: January 2020

Microbial resistance, oxidative stress, and inflammatory conditions are among the leading causes of death worldwide. In the current work, silver nanoparticles (AgNPs) were biosynthesized using the aqueous extracts of parsley, corn silk (CS), gum Arabic (GA) or combination of the three extracts. The formed nanoparticles were characterized using three techniques including transmission electron microscopy (TEM), UV-visible spectrophotometer and Fourier-transform infrared spectroscopy (FTIR). The antioxidant, anti-inflammatory, and antimicrobial activities were tested for the formed nanoparticles, the aqueous extracts of each of the three plants and their combination. Oxidative stress was induced by alloxan which promoted the development of diabetes mellitus in rats. Inflammation was induced by injecting carrageenan in rats’ paws. Pathogenic microorganisms causing serious urinary tract infection (UTI) were selected for the antimicrobial assay. All aqueous extracts and the biosynthesized AgNPs showed variable degrees of antioxidant, anti-inflammatory and antimicrobial activities, however, the AgNPs biosynthesized by the combination of the three aqueous extracts was the most effective one. LC/MS was done to identify the compounds present in the crude extracts that may be responsible for the observed biological activities. LC/MS resulted in the identification of 13 compounds. Docking experiments on COX-1 (cyclooxygenase-1) and COX-2 (cyclooxygenase-2) were performed to determine the compounds responsible for the anti-inflammatory activity of the extracts. The results showed that silver nanoparticles synthesized by the combination of the three aqueous extracts are considered promising candidates for the development of antioxidant, anti-inflammatory and antimicrobial agents.