bluuebunny/crossref_metadata_2025 huggingface dataset:
Physics education students’ perception on the use of motion detector in linear motion practicum
Authors: Hariwangsa Panuluh Albertus , Dian Atmajati Elisabeth , Dwi Kristanto Yosep
Published: March 2020

The use of technology in teaching and learning is very common today. In physics learning, practicum has an important role, namely deepening the understanding of concepts and applying concepts. However, it is interesting to know the importance of using technology in practicum. This study aims to know to know the student’s Physics education students’ perception on the use of motion detector in linear motion practicum The present study was descriptive research using a qualitative approach. This research was carried out in mechanics experiment class with 16 students as research subjects. This study used students’ reflection and interview in collecting perception’s of the students. The research found that practicum with motion detector has significant role in results obtained. On the other hand, practicum with motion detector has unsignificant role in the student’s carefullness.
Development of mathematical learning devices based on multimedia on circle materials of grade eighth of junior high school
Authors: Laurens Th , Laamena Ch. M.
Published: March 2020

This study aims to develop multimedia-based mathematical learning tools that are valid and practical in circle material. Learning tools developed are Lesson Plan, Teaching Materials and Student Worksheets. This type of research is development research that uses a 4-D (Four-D) development model developed by Thiagarajan and consists of 4 stages namely define, design, development, and dissemination, but due to time constraints, it is only limited to the development stage. The research subjects were seventh-grade junior high school students at the Angkasa Lanud Pattimura Ambon. The results of the study show that the learning devices developed are valid and practical. This is indicated by the general average validator rating for the three devices is 3.44; practicality of learning 92.98% and mastery of students taught by using the results of the development of 71.42%
Teacher’s questions on mathematics learning based on ELPSA framework
Authors: Rozalia  , Johar R , Duskri M , Khairunnisak C , Zubaidah T
Published: March 2020

Teacher’s question to encourage students to build their understanding is an essential aspect of mathematics learning. However, teachers show little concern about the quality of questions posed to students. Teachers can implement various strategies in conducting their roles as facilitators in developing students’ understanding. One of which is through questions. ELPSA framework requires teachers to ask questions to help students construct their knowledge. This framework consists of five components: Experience, Language, Pictorial, Symbol, and Application. This study discussed the profile of teacher’ questions based on ELPSA framework. The questions were classified into the types of questions, namely: factual, convergent, divergent, and evaluative questions. This study employed a qualitative research design using an observation sheet as the instrument. The participant of the study was a mathematics teacher from one of the junior high schools in Banda Aceh. The results concluded that the profile of teacher’s questions in Year 8 of one of the junior high schools in Banda Aceh developed for each component of ELPSA framework. These developments were indicated by the suitability of the types of teacher’s questions and the types of questions expected in the components of ELPSA framework.
Website design of Capita Selekta Mathematics Course for mathematics education students
Authors: Thahir Musa , Roza Yenita , Murni Atma
Published: March 2020

This article is based on the use of learning models that are limited to the subjects of Kapita Selekta Mathematics. This article aims to explore the results of the development of a website for learning Kapita Selekta Matematika (KSM) on UIN Suska Riau students that is valid, practical and effective. This research uses a development research model of Borg and Gall. The research instruments used in this article are validation sheets (validity aspects) by involving 6 validator lecturers, lecturer assessment sheets and student assessment sheets (practical aspects) involving 5 students, and student learning outcomes tests (aspects of effectiveness) involving 28 students. The data in this research is analyzed using quantitative and qualitative descriptive. This results in a course learning website which is valid (the average overall aspect of material validation was 4.15 and the average overall aspects of validation technology is 3.98), practicality score is 4.23 with the category “GOOD”, and effective (Sig. 0,000 <Sig (1-tailed) 0.05). Thus, student-learning outcomes after using the learning website are better than before using the learning website. Based on the tests carried out, the development of the overall learning website on the material and technological aspects can be categorized as feasible, while the practical aspects can be categorized as practical, so this learning website can be used as a learning medium to help the learning process.
Javanese calendar as context to learn number pattern and least common multiple
Authors: Zulkardi  , Setiawan M B T
Published: March 2020

This research is about to investigate how Javanese calendar and primbon could be used as context to learn number pattern, least common multiple and modular arithmetic for high school students. This article is the first step for the research, as this research only just reach preliminary stage at this point, which consist of validation on worksheet, one to one and small group to gain data about students’ understandings regarding connection between contexts as student perception with mathematics learning which they had learned. This research using Realistic Mathematics Education (PMRI) approach. The problems which given in this research was based PISA framework. The methodology of this research is using Design Research. This research produce valid and practical problem, worksheet for learning material and support students to understand more about number pattern and least common multiple as basis to learn modular arithmetic even as the learning material itself only just enrichment in national curriculum.
The teachers’ ability in mathematical literacy for space and shape problems on Program for International Student Assessment (PISA) adaptation test
Authors: Julie H , Sanjaya F , Anggoro A Y , Rudhito M A , Putra D P W
Published: March 2020

The teacher’s mathematical ability is one of the factors that influence the achievement of students’ mathematical abilities. In Indonesia, almost all research related to PISA, the subject of research was a student. It is still rare that the subject of research was a teacher. How is the math literacy ability of the teachers? This question will be answered by researchers in this study, especially in the field of space and shape. The subjects were seven Mathematics teachers who taught in junior high schools from seven different schools in Yogyakarta and surrounding areas. In the process of this research, the researcher makes a test adapted from PISA questions. There were 13 questions in the test consisting of three questions in the quantity field, three questions in the uncertainty field, three questions in the field of change and relationship, and four questions in the field of space and shape. In this paper, we will present our result just for the Space and Shape part. The study found that (1) 7 teachers could achieve level 4 for problem 1a, (2) 6 teachers could achieve level 5 for problem 1b, (3) 2 teachers could achieve level 5 for problem 2, (4) 1 teacher could achieve level 5 and 6 for problem 3, and (4) 6 teachers could achieve level 6 for problem 4.
Clinical and radiological assessment of the effect of low level laser therapy on delayed bone fractures healing
Authors: Al Balah Osama , Allam Ahmad , Aid Ghada , Tabl Eslam , Abdelfatah Alaaeldin
Published: March 2020

Low level laser has been conducted for treatment of bone fracture on animal and had shown positive results. If laser energy is delivered at optimal dose with appropriate parameters, it might get best results however a little research in the literature has conducted on the effect of low level laser on human bone fracture. The aim of the study was to assess the radiological and clinical difference of the effect of low level laser therapy on the delayed bone healing of patients with different bone fractures. This was a prospective study conducted in Benha university hospital on 33 patients with delayed and non-union of bone fractures via low level laser diode laser with a wavelength 905nm. There were 27 male 5 female patients, mean age group ±34.43 range (24 years to 67 years), the mean delayed of union was ± 6,68 range (3 months to 15 months ). At the end of the study, union is achieved in mean period±1,7( 1 month to 4,1 month)which led to success of about 70% improvement of the treated group, union mean number of sessions used ±23,375 (range 15 sessions to 50 sessions), Mean Visual Analog Scale (VAS) ± 1,3 range from (0 to 6). the present study indicate that Low level laser therapy is an effective modality for treatment of delayed bone fracture, can relieve pain and increase range of motion of the associated stiff joints with no adverse effect provided that adequate patient selection has conducted.
Optothermal response and Tissue Damage analysis during Laser Hair Removal
Authors: Okebiorun Micheal O. , Elgohary Sherif H.
Published: March 2020

Effective design of laser sources is crucial to optimum performance during Laser hair removal. Therefore, the thermal effect of laser sources was evaluated at wavelengths 694, 755, and 1064 nm at different fluence 4.5, 5.5, 10, and 15 J/cm2, respectively. The patient skin models are 3 photo types of a 3-layer 3D model of epidermis, dermis and hypodermis containing the hair shaft and follicle with thickness carefully selected to be in range of a normal human feature. Monte Carlo method, Bio heat transfer and thermal damage analysis using Arrhenius formula were employed. Results show that a laser source of 10-15 J/cm2, at 755 nm wavelength is optimal for light skinned and moderate skinned while 4.5 -10 J/cm2, 755-1064 nm is optimal for dark skinned people for a pulse width of 0.1 sec. This work would assist researchers and manufacturers in the design and development of hair photoepilation devices.
The Effect of Temperature on the Optical and Analytical Properties of PET Polymer Used in Drinking Water Bottles
Authors: Hamdy Omnia , Tawfik Walid
Published: March 2020

Polyethylene Terephthalate (PET) polymer has been utilized in many applications including, optoelectronics, radiology and food packaging due to its resistance to weak acid, organic solvents, and oils, in addition to low density and low cost. However, physical, mechanical and optical properties of PET are highly dependent on some ambient conditions like temperature since its thermal deformation temperature is 76º C. In this work, the effect of increasing the ambient temperature on the PET material used in the fabrication of plastic water bottles was studied optically and analytically. The optical attenuation coefficient was considered at different room temperature ranging from 25 °C to 45 °C emulating hot-sun-days ambient conditions in the laboratory. The elemental composition of the selected polymers was achieved using laser induced plasma spectroscopy (LIPS) technique showing Al emission line at 257.5 nm and CN emission line at 386.1nm in the sample-generated plasma. The optical attenuation coefficient has showed a dramatic increase with the temperature which may lead to leaching of some toxic elements existed in PET polymer into the bottle’s water content during hot weather and cause health problems.
Study of Nonlinear Polymers Operating Parameters for Laser Pulse Chirping
Authors: Nada Y. S. , El-Azab J. M. , Othman H. , Mohamed T. , Maize S. M. A.
Published: March 2020

In this study, the optimization of the operating parameters of nonlinear polymers for self-phase modulation is reported. The effect of delocalization length and adding function groups (donor-acceptor groups) on the nonlinear refractive index are investigated. Based on nonlinear Schrödinger equation, the pulse chirping factor, for a set of nonlinear polymers, at different operating conditions, is studied. The comparison between laser pulse chirping factor resulting from saturated and conjugated polymers is presented. It is noticed that the chirping factor that evolved from conjugated polymers is greater than its equivalent in saturated polymers. Moreover, laser pulse chirping factor is increased with increasing of delocalization length. Therefore, this study may initiate the synthesis of new nonlinear polymers in order to produce appropriate nonlinear optical properties for high broadening materials in laser compression systems.
Three-Dimensional Holographic Reconstruction of Brain Tissue Based on Convolution Propagation
Authors: Abdelazeem Rania M. , Youssef Doaa , El-Azab Jala , Hassab-Elnaby Salah , Agour Mostafa
Published: March 2020

In this study, a dynamic holographic projection system for brain tissue and its anatomical structures extracted from Magnetic Resonance (MR) plane slice is reported. Computer holograms are calculated using a modified Gerchberg-Saxton (GS) iterative algorithm where the projection is based on the plane wave decomposition. First, brain anatomy includes white matter (WM), grey matter (GM) and brain tissue are extracted. Then, phase holograms using the proposed method are generated. Finally, single-phase hologram for the whole brain anatomy is generated and is optically reconstructed by a phase-only spatial light modulator (SLM) at different depths. The obtained results revealed that the three-dimensional holographic projection of MR brain tissue can aid to provide better interpretation of brain anatomical structure to achieve better diagnostic results.
Research on Floor Response Spectrum of Shielded Building Structure under Seismic Loading
Authors: Chen Yang , Xiong Cheng , Ma Tengfei , Zeng Wenlin , Wang Juan
Published: March 2020

As a clean energy source, nuclear power has broad prospects for development. It is of great significance to study the seismic response of nuclear power plants. PLAXIS software is used to establish the whole finite element model of AP1000 nuclear power plant shielding plant structure. Considering the foundation embedding and soil-structure interaction, the seismic response analysis of nuclear power plants on different inclined soft rock sites was carried out under seismic loading. By analyzing and comparing the calculated results of the floor response spectrum amplification factor, the peak frequency of the floor response spectrum at the important position is smaller than the peak frequency of the design response spectrum, the inclination of the inclined site will affect the peak frequency and cause the amplification effect.
Estimation on stress concentration factor of remanufacturing notch for TC4 titanium alloy
Authors: Ding Mingchao , Zhang Yuanliang , Xian Hongwei
Published: March 2020

Remanufacturing notch would be produced after crack polishing in remanufacturing pre-treatment. In the present study, stress concentration of remanufacturing notch was investigated by a series of semi-elliptical notch models using finite element analysis. Comparing with notch width, notch depth has a critical effect on stress concentration. An equation to estimate stress concentration factor (SCF) has been modified to be suitable for remanufacturing notch. Based on the pre-estimation of stress concentration for remanufacturing notch, references on crack polishing plan can be provided in the remanufacturing field.
Synthesis and Photophysical Properties of Small Molecule Donor Materials Based on Indacenodithieno[3, 2-b]Thiophene Core for Organic Solar Cells
Authors: Zhang Chao , Liu Kai-Kai , Zhang Han-Jian , Wang Jin-Liang
Published: March 2020

We synthesized a small molecule donor material based on IDTT for solar cells, named C6S2ThBSeIDTT, which was obtained by IDTT-2SnMe3 and a capping fragment by a simple Stiller coupling reaction. Its structure and properties were HNMR. C6S2ThBSeIDTT was confirmed that it exhibited good solubility in conventional organic solvent. It can be found that strong intermolecular charge transfer (ICT) exists in the D-A-D-A-D conformation. It has been found to have broad and strong absorption by absorption spectroscopy with a medium wide band gap of 1.70 eV, and will well agree with fullerene acceptors such as PC60BM and PC71BM for efficient bulk heterojunction solar cells.
Dynamic characteristic analysis of double-column machine bridge of spillway gate
Authors: Sun Naidong , Yang Lingqiang , Wang Zhenyu
Published: March 2020

The machine bridge has problems in many earthquake cases, such as cracking at the end of the column, excessive local displacement, and even severe damage. To improve the seismic property of the machine bridge, a new design method is proposed, namely the double-column machine bridge. The finite element analysis is used to analyze the dynamic time history of the structure, and the stress and displacement of the structure during the earthquake action are studied. In addition, the collision analysis between the machine bridges is carried out, which is based on the results of the three-dimensional finite element calculation. The results show that the double-column machine bridge has better seismic performance. Compared with the ordinary machine bridge, the displacement and stress of the new structure under the large earthquake are obviously reduced. By optimizing the structure, the collision between structures can be effectively avoided.
Review of biogas models and key challenges in the further development in China
Authors: Chen Lihong , Frederiksen Pia , Li Xin , Shu Bangrong
Published: March 2020

This paper provides an overview of biogas models and key challenges of further biogas development in China. A review of the biogas models aim to highlight the complexity of biogas development in China, and thereby draw attention to some easily neglected issues in China’s biogas development. China’s biogas development had stagnated in recent years, and while household biogas projects have always been the leading force of biogas production in China, their proportion declines year on year. “3 in 1”, “4 in 1” and “5 in 1” models are the most common models used in China, but Medium and Large-scale Biogas Projects (MLBPs) increasingly play a significant role. By comparison, MLBPs perform better than household biogas projects in some aspects. On the other hand, household projects have their advantages and are essential aspects of energy system development, particularly in more remote rural areas. This paper strongly recommends paying more attention to the practical application of household biogas models and providing the necessary support to skill development and digester maintenance. Moreover, this paper argues that biogas policies need to be based on scientific evidence.
The effect of thickness on properties of three-phase piezocomposites
Authors: Xu Junan , Wang Likun , Zhong Chao
Published: March 2020

In this study, three-phase piezocomposite is fabricated on the basis of the 1–3 composite structure and the cutting–filling method. The 1–3 piezocomposite is used with PZT-5A as the piezoelectrics and epoxy/silicone rubber as the matrix. The relationships between the performance parameters of the 1–3 composites and different thicknesses are analyzed via finite element simulation and experimental measurement. Composite samples with thickness of 3mm-10mm are prepared through an experiment and tested using an impedance analyzer. Simulation results agree well with experiment results, thereby indicating that the composites have a high electromechanical coupling coefficient.
Research on EP reinforced by nanoSiO2/Al2O3/ZrO2 and its mechanism
Authors: Xu Xuefeng , Cai Yuebo
Published: March 2020

Epoxy resin is modified by nanoSiO2, nanoAl2O3 and nanoZrO2 dispersed by dispersing agent by combining the means of high-speed mechanical stirring and ultrasonic cavitation. It aims at studying the influences of different nanometer-particles types and its dosages on the properties of composite. Research results show that the optimum dosages of nanoSiO2, nanoAl2O3 and nanoZrO2 are 1%, 3% and 5% separately. The tensile strengths of three kinds of composites are similar when it is added by its optimum dosages. The mechanisms of reinforcing epoxy resin caused by nanometer-particles are investigated by combining the SEM.
Study on Gas Distribution and Migration in Stope Based on Gas Monitoring
Authors: Zhang Yang , Li Huashuo , Guan Yongxing , Tang Shoufeng , Tong Minming
Published: March 2020

If the safe concentration of gas in coal mine exceeds the upper limit, it will bring great risks to coal mine production. Therefore, it is of great significance to study the distribution law of gas concentration on coal face. This paper established the layout plan of gas sensor, measured the gas concentration of each observation point under the wind speed of 3m/s, established the trend surface model of first order to fifth order, and solved the trend surface equation of each order, obtained the best trend surface equation through a variety of testing methods, and studied the gas distribution and migration rules in detail.
Research on layout optimization of freezing pipes based on numerical calculation of hydro-thermal model
Authors: Zhang Song , Zhang Jiwei , Han Yufu , Su Yanlin , Zhang Song , Wen Hanhong
Published: March 2020

In order to study the influence of seepage flow on the development of frozen curtain in the artificial ground freezing project and optimize the distribution of freezing pipes. A coupled hydro-thermal model base on Darcy law and thermal balance equation has established and verified by the model test. The result shows that it can effectively improve the efficiency, reduce the completed freezing time and strength of frozen soil curtain. And the best distance which is all gratefully acknowledged between freeze pipe in upstream and section of original design freeze pipes is 75% of the distance of freeze pipes. In the end, the influence range of one pipe in upstream will be 3∼4 times the distance of freeze pipes.
A Combustible Dust Cleaning Device and Application
Authors: Li Yanping , Li Yong , Li Yunqi , Fang Liu
Published: March 2020

Flammable fine dust is dangerous to working environment. It is harmful to the health of workers. In this paper, a high efficiency combustible dust cleaning device is proposed. Its water consumption is about 0.289 kg/m3, and the removal rate of dust with particle size less than 5 m is higher than 99%. This new cleaning device can be used in coal conveying system of power plant and other workplaces.
Preliminary Study on the Evaluation System of Technological Innovation Index for the Central Enterprises of International First-class Enterprises
Authors: Chang Yan , Shi Yongpeng
Published: March 2020

The State-Owned Assets Supervision and Administration attached great importance to the construction of technological innovation capabilities of central enterprises, and clearly proposed to study the evaluation index system of technological innovation capabilities of central enterprises, carry out evaluation of technological innovation indexes, and guide and encourage enterprises to upgrade the level of technological innovation. Technological innovation has become a powerful driving force for continuously promoting the scientific development of central enterprises. It is of great significance for accelerating the improvement of the level of technological innovation of central enterprises to carry out the evaluation of central enterprises’ technological innovation index, establish an effective mechanism to guide technological innovation of all departments, and provide scientific decision-making basis for technological innovation of central enterprises. The core of this research revolves around the technology innovation index of central enterprise for building a world-class enterprise. First, systematically sort out the characteristics of technological innovation in world-class enterprises. Second, analyze the characteristics of technological innovation of central enterprises and the shortcomings of current state-owned enterprises’ technological characteristics compared with first-class enterprises. Third, build a technology innovation index evaluation system of world-class enterprises.
Study on Combustion Dynamic Performance of Woody Plant Based Hydrocarbon Fuel
Authors: Zhang Aihua , Wang Qin , He Yidan , Lai Pengying , Miu Yifu , Xiao Zhihong
Published: March 2020

Woody plant oil is a kind of biological material which occupies an important position. It has many characteristics, such as wide variety, wide distribution, large yield and reproducible. The thermochemical conversion technology of woody vegetable oils is an efficient conversion route, and the obtained hydrocarbon-rich fuel can maximize the proximity to existing fossil fuels by esterification and acid reduction. At present, the research on the combustion performance of hydrocarbon rich fuels is relatively few. In this study, B20 (hydrocarbon enriched fuel 20%, 0# diesel 70%) and 0# diesel were used for reference. The results show that, under the same conditions, the emission performance of B20 (smoke, CH, CO, NOx) of the woody plant based hydrocarbon fueled fuel is better than that of 0# diesel. The dynamic performance (torque performance, power performance) is basically equal to that of 0# diesel, and it can protect the ecological environment well, and has a good application prospect.
Study on Production Efficiency of Flue-cured Tobacco in China Based on DEA-Malmquist Model
Authors: Huang Dongbing , Wang Xinlei
Published: March 2020

Based on the input-output data of flue-cured tobacco production in 18 provinces of China from 2005 to 2016, the flue-cured tobacco production efficiency was calculated and analyzed. The results show that: Firstly, the total factor productivity (TFP) of flue-cured tobacco in China shows a growth trend, the main reason of the growth is the growth of the scale efficiency. The pure technical efficiency and the technical progress play a negative role to the promotion of total factor productivity. Secondly, in the provinces where total factor productivity declines, the leading factors of total factor productivity declines are different. For the provinces where total factor productivity increases, the leading factor of total factor productivity growth is the improvement of technical efficiency. Thirdly, the change of annual total factor productivity growth rate is unstable because of the uncoordinated change of technological progress and technological efficiency. We can improve the flue-cured tobacco productivity by large-scale production, improving management level, introducing advanced production technology and strengthening technological innovation.
Adsorption mechanism of azophloxine in water by Fe3O4-chitosan composite material
Authors: Sun Li , Song Xiaoxiang , Yuan Zhigang , Liu Ying , Gong Wenbang , Xu Wei , Mei Shunqi
Published: March 2020

Fe3O4-chitosan composite material was synthesized as adsorbent. The effect of solution pH value, initial concentration of azophloxine and adsorption time on the adsorption of azophloxine onto adsorbent was studied. The results show that Fe3O4-chitosan composite material can be magnetically separated before and after adsorbing azophloxine. It was found that the peak intensity of azophloxine was the strongest under weak acidic conditions, and the peak position hardly shifted. In the process of adsorption, it was found that Fe3O4-chitosan composite material adsorbing azophloxine by the surface electrostatic attraction. The optimum equilibrium adsorption capacity is at initial solution pH 6, and the equilibrium adsorption capacity is very close under weak acidic conditions. The pseudo first-order and pseudo second-order kinetic models were applied to experimental data. The adsorption process followed the pseudo-first-order kinetic model, which implied that the adsorption process was physical adsorption. The correlation coefficient for the first-order kinetic model was obtained greater than 0.99571 at room temperature, and the theoretical equilibrium adsorption capacity qe,cal value also agreed very well with the experimental equilibrium adsorption capacity qe
value in the case of pseudo first-order kinetics. It is suggested that Fe3O4-chitosan composite material has a wide application prospect in the removal of dyes as adsorbent.
Study on the influence of the number of broken windows on the fire of running trains
Authors: Ma Shuo , Liu Wan Fu , Han Wei Ping , Xia Jian Jun , Liu Ya
Published: March 2020

With the rapid development of Railway Construction in China, the safety of railway trains has aroused people’s concern while solving the traffic problems of passenger flow in various cities. According to the principle of relative motion, this experiment studies the fire burning characteristics of trains at different travel speeds by changing the wind turbine frequency to adjust the wind speed. The experimental results show that when the train window breaks during travel, the fire heat release rate increases with the increase of running speed. The growth coefficient of fire increases with the increase of running speed. With the increase of train running speed, the variation of the temperature extremes of the ceiling and the temperature series on both sides of the fire source is not very large.
Screening of the best formula for flame type high energy burner
Authors: Chen Jialin , Guo Tao , Ding Wen , Zhang Sheng , Wang Qiong , Yao Miao
Published: March 2020

In order to explore the best formula of flame-type high-energy burner, this paper selects 7 groups of flame-type high-energy burners with good stability, high energy and a wide range of raw materials based on the existing literature and patents. The Gibbs free energy Values of 7 groups of formulations at different temperatures were calculated by using the chemical thermodynamic formula, and the changes in Gibbs free energy Values of 7 groups of formulations were drawn, which provided a basis for the calculation of reaction rate k value by Eyring equation. Then, according to the calculation theory of chemical reaction calorific value, the heat of reaction of 7 different formulations at different temperatures was calculated. The results show that the Gibbs free energy value of Al/MnO2 in the seven groups of formulations is much smaller than that of the other groups in the same reaction temperature environment, and decreases with increasing temperature. According to the Arrhenius formula and the Eyring equation, the reaction rate of Al/MnO2 is the fastest in each group. When the other conditions are constant, the reaction enthalpy of Al/MnO2 is the smallest in each group, therefor the heat released by the reaction is the most. In summary, under the same quality conditions, the Al/MnO2 flame type high energy burner formulation has the fastest reaction rate and the most heat release, which provides theoretical guidance for experimental design and practice.
Effect of Fuel Ignitability and Volatility on Ultra-Fine Particulate Emissions in Diesel Engine
Authors: Wang Xiaodan , Tang Xintong , Yang Jing , Ren Xiaoping , Liu Jianhong
Published: March 2020

The effects of fuel components on particulate matter emissions were studied on a high pressure common rail diesel engine fuelled with different diesel fuels. Six kind of diesel fuels with various volatility and ignitability were selected in this test. Particle number, composition and morphology were studied with various physicochemical property diesel fuels. The results show that lower ignitability fuel and stronger volatility fuel could reduce the accumulation mode particle number, while the nucleation mode particle number would increase. Meanwhile, the proportion of DS might reduce with the SOF increase. With the decrease of the fuel cetane number, the number of large cluster particles in the exhaust decreased obviously.
Preparation of copper nanowires conductive films by using cuprous oxide nanowire as template
Authors: Liu Weixiao , Wang Yanyan , Dong Lei , Huang Manman , Ying Shuyang , Peng Changsi
Published: March 2020

Polypyrrole-coated cuprous oxide nanowires with a large aspect ratio were prepared via the hydrothermal reduction of copper acetate with pyrrole. Initially, the nanowires were transferred onto a glass substrate by suction filtration and embossing. A copper nanowire conductive film can then be obtained after high temperature annealing reduction and transferred onto a flexible substrate via hot press transfer. The product was analyzed via X-ray powder diffractometry, scanning electron microscopy, and transmission electron microscopy. The visible light transmittance and the surface resistance of the sample were measured by employing an ultraviolet-visible spectrophotometer and a four-probe surface resistance meter, respectively. The effects of the annealing temperature, of the time, the dispersion of the square resistance, and the transmittance of the conductive film were investigated. The results show that the conductive film exhibits a high visible light transmittance (82%) and a low sheet resistance (62 Ω/sq) upon annealing at 700 °C for 300 seconds.
Deep Water Oil & Gas: New Opportunities and Suggestions for Chinese Oil Companies
Authors: Li Jia , Peng Yun , Sun Dufen , Yi Jiexin , Wang Kai , Liang Tao
Published: March 2020

The rising production of Deepwater are reshaping the global market landscape. Global Deepwater production will account for 22% to 25% of international supply in 2035. The role of Deepwater is significant in the future. The oil companies have entered Deepwater fields extensively. New opportunities are emerging, and the number of tenders for deep water blocks is increasing. Deepwater terms are changed to attract more exploration investment to the sector. The efficiency of Deepwater operation has been greatly improved through project optimization and technological progress. Chinese oil company should participate in international competition and cooperation actively, extend and upgrade the whole offshore industry chain to seize the new opportunities.
A Comparison of Two Different Surface Modifications on the Properties of Poly (p-phenylene benzobisoxazole) Fibers
Authors: Liu Lanlan , Li Wenbo , Gu Su , Zou Dehua , Li Zhihua , Yang Jiani
Published: March 2020

Poly (p-phenylene benzobisoxazole) (PBO) fibers were modified by coupling agent 3-Glycidoxypropyltrimethoxysilane (KH-560) and polyphosphoric acid (PPA) respectively. The influence of two treatments on the properties of PBO was investigated, including surface morphology, water absorption and breaking strength retention ratio. The results indicate that the surface roughness of PBO fibers can be increased by both KH-560 and PPA. With the increase of PPA mass fraction, the retention rate of breaking strength of PBO fibers gradually was decreased, and the water absorption rate was gradually increased. Notably, KH-560 can effectively improve the water absorption rate without deteriorating mechanical properties of PBO fibers simultaneously. Compared to treatment by PPA, KH-560 has a milder effect on the performance of PBO fibers, which makes it easier to control the degree of surface modification.
Mechanism of wind power and solar photovoltaic power participation in the electricity spot market considering the guaranteed capacity factor
Authors: Tang Chenghui , Zhang Fan
Published: March 2020

At present, with the increasing penetration rate of renewable energy in China, it is necessary to consider renewable energy in the electricity spot market. However, wind power, solar photovoltaic power, etc. are the kind of “priority power generation”, which uses the catalogue price for the part of the guaranteed capacity factor and the market price for the rest part. The above two pricing mechanisms need to be coordinated in renewable energy consumption. This paper proposes a mechanism of renewable energy participation in the electricity spot market, which enables renewable energy participating in the spot market as other conventional energy sources under the policy of “priority power generation”.
Domestic and Foreign Energy Internet Construction Experience and Enlightenment
Authors: Li Nan , Zheng Kuan
Published: March 2020

In this paper, firstly the overall energy structure and energy power development route of major developed countries are analyzed, and practice situations of energy internet engineering of different countries are analyzed by taking the United States, Germany and Japan as an example. Secondly, the overview, technical scheme and comprehensive benefits of typical domestic energy internet projects are analyzed. Finally, experience is summarized and suggestions are put forward for China’s regional energy internet construction in terms of key technologies, operation model and pilot construction.
Recent progress in conversion of carbohydrate biomass and their derivatives to γ-valerolactone
Authors: Guo Yalin , Yang Qiancai , Guo Pengfei , Yao Guodong , Jin Fangming
Published: March 2020

Biomass, the only renewable resources of fixed carbon, shows great potential to ease the pressure on fossil energy crisis. In recent years, conversion of carbohydrate biomass into value-added products has been vastly reported. Gamma (γ)-valerolactone (GVL), which is one of the platform chemicals, has been extensively used in industrial production. Recent trends proposed an eco-friendly processing using water and biomass-derived materials as hydrogen sources instead of high-pressure and high-purity gaseous hydrogen, avoiding storage, transportation and operation risk in the production. This review summarizes the progress in GVL production from carbohydrate biomass and highlights the novel green approach by using green reductants and non-noble-metal catalysts.
Research on Thermal Out of Control of Lithium Battery in New Energy Vehicles
Authors: Wang Lili , Yang Xuefeng , Wang Qiang , Tian He
Published: March 2020

Lithium-ion batteries are widely used in the new energy automobile industry due to their high energy density, fast charging, high cycle life and no pollution. However, in actual use, lithium-ion battery systems may cause deflagration of the power battery system due to thermal runaway. In this paper, the causes of the thermal runaway of the power battery system are studied, and the existing related suppression methods at home and abroad are compared and analyzed, and the advantages and disadvantages of the relevant suppression methods are obtained.
Study on the surface activity and aggregation behavior of a polyether surfactant for acidification
Authors: Ning Mengmeng , Wang Peng , Xu Zhengdong , Huang Bohua , Li Ning , Kong Weizhong , Jia Jiangfen , Zeng Zhiguo , Liu Qilun
Published: March 2020

Four kinds of biological phenolamine resin block ethers (BPPC) surfactants with different molecular weights were synthesized from biological phenol, formaldehyde and polyvinyl polyamines. The structure of BPPC was characterized by Ft-ir and H NMR. The surface properties of BPPC polyether surfactant and the change curve of surface tension with concentration in aqueous solution at different temperature were studied by surface tension method. The results showed that the critical micelle concentration (cmc) of BPPC and the γcmc increased with the increase of EO content. With the increase of molecular weight, number of branched chains and length of branched chains, cmc and γcmc decreased. The thermodynamic calculation results show that BPPC shows enthalpy/entropy compensation during micellization in aqueous solution. The compensation temperature T was all (300±2) K, and with the increase of molecular weight, number of branched chains and length of branched chains, the stability of BPPC formed in aqueous solution was enhanced.
Experimental Analysis and Research on New Concrete Multi-ribbed Beam Hollow Floor
Authors: Wang Dunqiang , Li Jingyu
Published: March 2020

The new concrete ribbed beam hollow floor cover based on the two-way ribbed beam is suitable for projects with large loads or large spans on the upper part. This paper mainly introduces the characteristics and composition of concrete ribbed beam hollow floor, collates and analyzes the test data obtained from the static loading test of the floor, obtains the structural performance of the test piece, and obtains the vertical overall displacement of the floor. The vertical displacement of the mid-span and the development of the crack, the ultimate bearing capacity of the hollow slab with the rib beam is obtained through the failure test. Under the normal load, the new ribbed hollow floor has good integrity. It is concluded that the hollow ribbed hollow floor cover has the characteristics of large bearing capacity and good overall rigidity.
Entropy Analysis of Two Phase Flow Pattern Identification in Vertical Tube
Authors: Lu Kun , Ma Longxin , Li Gen , Shang Wei , Feng Yixuan
Published: March 2020

This paper aims to analyze the time domain marginal spectral entropy of differential pressure signals collected from the gas-liquid two-phase flow pattern vertical tube bundle channel on the experimental platform. By comparing the visualized and measured differential pressure signals, four flow patterns were found, namely, bubble flow, bubble-mixed flow, agitated flow, and annular flow. The marginal spectral entropy values of the four flow patterns are calculated, and it is found that the spectral entropy distribution regions of the different flow patterns are different. Putting the aforementioned four flow patterns that is regarded as the feature quantity into artificial neural network support vector machine for flow pattern recognition. The experimental results show that the marginal spectral entropy can better reflect the flow difference between different flow patterns. The support vector machine has the advantages of fast calculation speed and high recognition rate. The overall recognition rate of the four flow patterns (the transition flow is included) is as high as 95.31% by combing the marginal spectral entropy with the support vector machine, which is suitable for online identification of flow patterns.
Erosion Resistance of Ceramic Particle Reinforced MMC Coating
Authors: Fang Jianjun , Li Yanping
Published: March 2020

There are relevant reports on preparing TiB2 particle reinforced metal matrix composite (MMC) anti-wearing coating by plasma spraying and HVOF spraying methods successfully. The research uses high velocity electric arc spraying with low cost and convenient operation to prepare four TiB2 particle reinforced composite coatings (MMC) with high bonding strength and uniform tissue. The results indicate the coating has excellent erosion wearing resistance.
Experimental Study on Heat Transfer Performance of White Smoke Reduction Heat Exchange System
Authors: Wang ZhenHuan , Zhao XinXue , Kwon YoungChul
Published: March 2020

In the present study, the white reduction system was designed and manufactured to evaluate the performance of a heat exchange system using a wave heat exchanger. The reducing effect of white smoke and the amount of heat recovered from cooling water were investigated experimentally using the cooling and dehumidifying method. The white smoke reduction system consists of two parts; the generating part and the reducing part of white smoke. When the air-water heat exchanger (A/W) and the SA (supply air) induced draft fan (SA Fan) are simultaneously activated, From the experimental results, we can see that the absolute humidity reduction rate of EA (exhaust air) was 82.9%, and the temperature rate of EA was 68.1%.
Empirical Study on China’s Energy Development under the Target of Carbon Emissions
Authors: Wu Hao , Zheng Li-Xin
Published: March 2020

Carbon dioxide is the inevitable product of the use of fossil fuels and is the main cause of global warming. In 2018, global carbon dioxide emissions reached 33.89 billion tons. Under the Kyoto protocol, countries are taking measures to reduce carbon emissions. China has pledged to peak its carbon emissions by 2030 and will work hard to reach the peak as soon as possible. This paper studies the development trend of fossil energy and the development space of renewable energy in China under the constraint of carbon emission by using mathematical models from an empirical perspective, and briefly analyzes its feasibility, and obtained preliminary conclusions. By 2030, total energy consumption will increase by 34 percent, fossil energy by 17 percent and non-fossil energy by 116 percent, accounting for about 24.4 percent of total energy consumption. This paper will forecast the total energy consumption from 2019 to 2030 according to the calculation model.
THE STUDY ON MECHANICAL PROPERTIES OF VARIOUS FIBER REINFORCED CEMENT-BASED COMPOSITE CEMENTITIOUS MATERIALS
Authors: Chen C. Q. , Zhang W. , Wu H.J. , Wang R.
Published: March 2020

Fiber can improve the bending strength of cement mortar or concrete due to its high toughness. The straw fiber, SF and PF with different properties were mixed into the mortar in the same proportion and different mixing processes to prepare mortar specimens, and the different types of fibers were mixed for the standard curing 7d and 28d. The mechanical properties of the test piece affected the change in this study. The results were showed as follows: the strength of the mortar with straw fiber was higher than that of the post-mixing method, and the flexural strength (referred to as FS) was increased by about 16.0%; the FS of the mortar after the SF was added by 9.7% higher than that of the first blending method, but the compressive strength(referred to as CS) of the first mixed mortar was higher than that of the post-mixing method 16.9%, indicating that the SF had a high modulus of elasticity, which could improve the CS; the growth trend between the FS and CS of the mortar were close with PF. Under the SF first mixing process, the CS was maximized, followed by the PF at the post-mixing method, and the worst was the post-mixing method of the straw fiber.
Study on manufacturing and mechanical properties of UHMWPE knitted structural reinforcement in composites
Authors: Jia Mengge , Wu Mengjin , Yan Ruosi , Ma Xiaohong , Wei Sainan , Zhang Wei
Published: March 2020

In this paper, four kinds of UHMWPE knitted reinforcement with plain, interlock, swiss pique and purl stitches were prepared respectively to explore the influence of different knitted structures on the mechanical properties of reinforcement. The properties of each UHMWPE knitted structural reinforcement were compared by tensile, tear and puncture tests. The results show that interlock has obvious advantages over other structures in various mechanical experiments, which provides a good choice for preparing knitted structure reinforcement for composites.
Analysis on the microstructure of sands
Authors: Zhang Weihua , Zhao Chenggang , Zhang Yinping
Published: March 2020

The macroscopic behavior of sands is closely related with its microstructure. Starting from the microstructure of sands, using micromechanics and integrated with statistically homogenization, considering intergranular contact force and branch vector, the paper focuses on the expressions for macroscopic stress; Integrated with the fabric characteristics of granular material, the second-order fabric tensor F is derived, and the relationship between stress-force-fabric is established. It shows that the macroscopic stress of sands is closely directed with inherent and stress-induced anisotropy, and the tendency between shear strength and fabric is same which lay the foundation for the following constitutive relationship for sands.