bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonic extraction and identification of carp scale collagen
Authors: Gao Qianqian
Published: January 2021

In this experiment, the carp scale as raw material, containing calcium and protein impurities in the scale and so on, respectively by two sodium EDTA (EDTA two sodium, EDTA) and sodium chloride solution (sodium chloride, NaCl) solution and its removal, scale collagen protein extraction and design. By using different single factor test the 4 factors determine the extraction of collagen during the experiment the optimum extraction process, the 4 factors are the enzyme (pepsin) dosage, ultrasonic time, solid-liquid ratio, extraction liquid (acetic acid) concentration of glue. The optimum extraction process for raw protein ultrasonic time 200Min, enzyme dosage 300mg/g, extraction concentration of 0.3 mol/L, the ratio of material to liquid 1:40 (g/mL), in this condition, the extraction rate was 28.7. By UV spectrophotometer identification, the material in the 230nm have obvious absorption peak, so the test the material of collagen.
Combustion Adjustment in Initial Startup Stage of 660MW Supercritical Fossil Power Unit
Authors: Du Jianqiao , Wang Chaoyang , Lu Xiao , An Guoyin , Yan Huibo , Ma Hui , Yan Xiaopei
Published: January 2021

In order to better improve economical efficiency, the newly built supercritical units mostly adopt more fuel-saving ignition mode, but in the initial startup stage, the parameters of unit and boiler are not compatible. This paper carries out study and analysis on parameters in the initial startup stage, and optimizes all parameters by adjusting startup feed-water quantity, fuel quantity, air volume and ratio for several times. With favorable effect, this paper may be used as good reference for other similar units.
Quantitative Structure Activity Relationship Analysis of Polypropylene during Ultraviolet Aging Based on Tensile Strength
Authors: Chen Kui , Zhang Tianyun , Liu Guangqiao , Zheng Xiaoping
Published: January 2021

In order to improving ultraviolet radiation (UV) aging resistance of polypropylene (PP) and expanding its application range, it is necessary to research the rule and mechanism of PP in UV aging process. On the base of Fourier transform infrared spectroscopy and differential scanning calorimetry characterization, the variations of structure parameter (crystallinity and carbonyl index) of homo-PP corresponding to different UV aging time were calculated and analyzed. Combined with tensile strength testing, the influences of both crystallinity and carbonyl index on tensile strength in UV aging process of PP were researched. Then the relationship formula between tensile strength and structure parameter was constructed based on linear relationship, and the quantitative structure-activity relationship of PP during UV aging was analyzed. The results show that, with the extending of aging time, the influence of crystallinity on tensile strength of PP declines, while that of carbonyl index is on the contrary. During UV aging, the tensile strength of PP rises slightly with the increase of crystallinity first, then acceleratedly declines for the increase of carbonyl index. It should be noted that, although the crystallinity of PP begins to decline after 100 h UV aging, its effect to tensile strength can’t be ignored while aging time is less than about 300 h.
Research on Defect Detection Method of Whole Surface of Small Ball Based on Field Scan
Authors: Zheng Runze , Chen Xin , Cai Xiaoyu , Wei Jiasi , Li Yuan
Published: January 2021

This paper introduces a detection method that uses a white-light interference microscope to scan along the circle of latitude line to detect defects on the entire surface of microsphere with a diameter of 2mm. The surface of the microsphere is exposed under the white light interference microscope from the top to the equator in turn according to the annular belts of different latitudes to make the acquired image cover the entire surface of the ball. The topography data is processed, the defects are identified, and the number of defects of different horizontal and vertical sizes is counted, so as to achieve the quantitative evaluation of the surface defects of the small ball.
A Preliminary Study on Testing the Compressive Strength of Sleeve Grouting Material Based on the Leeb Hardness Method
Authors: Ding Chenchen , Gu Sheng , Yuan Yiwei , Wu Yulong
Published: January 2021

In order to explore the feasibility of testing the compressive strength of sleeve grouting material in practical engineering by the Leeb hardness method, we made 12 groups of standard specimens out of grouting material, analyze the correlation between surface hardness and compressive strength of grouting material by experiments. Experimental results show that, The surface hardness test results of the sleeve grouting material are in accordance with the normal distribution. With the guarantee rate of 95%, eliminating the extreme value in the hardness test data can significantly reduce the discreteness of the data and improve the accuracy of the calculation results. There is a significant correlation between surface hardness and compressive strength of grouting material, the best fitting effect is by using exponential function, the average relative error is 7.45%, the relative standard deviation is 8.61% and the correlation coefficient is 0.864. The experimental results provide a reference for testing the compressive strength of sleeve grouting material by the Leeb hardness method.
A simple prediction method for the permeability coefficient of water-bearing sand layer after grouting compaction
Authors: Chen Jiale
Published: January 2021

Due to the particularity of the pumping of the compound paste slurry material, the traditional stress analysis method is difficult to apply. Based on the cylindrical hole expansion model of compacted grouting, the theoretical formula of the compacted grouting displacement field of soil is established on the basis of simplified body strain. Based on the displacement field theory, the analytical solution of the soil permeability coefficient after grouting and compaction is established according to the compressed porosity and Konzeny-Carman equation. The field test of compact grouting was carried out, and the water injection test was used to obtain the change of permeability coefficient before and after grouting under different grouting intervals. The obtained results are in good agreement with the theoretical solution and have certain engineering guidance significance.
Synthesis and characterization of polyimides containing pyridine ring
Authors: Li Zhun , Wang Ying , Zhu Shaomin
Published: January 2021

Monomer 2,2’-bis [4-(5-amino-3-methyl-2-pyridoxy) phenyl] propane was successfully synthesized by 2-chloro-3-methyl-5-nitropyridine and bisphenol A, and the structure of pyridine diamine monomer was confirmed by 1HNMR. A series of polyimides were prepared by two-step polymerization of the pyridine diamine monomer with five aromatic dianhydride monomers. The results show that the polyimide films had good thermal stability and mechanical properties. Tg was 236-300°C in DSC test and 240-299°C from DMA test, T5% and T10% weight loss at N2 were 470-492 and 499-515°C, respectively. Moreover, the polyimide films showed outstanding mechanical properties with tensile strength of 72-90MPa, tensile modulus of 1.8-2.4Pa, and breaking elongation of 5-12%. The cut-off wavelength was 338-399nm.
Study on magneto-acousto-electrical tomography based on laser-excited ultrasound
Authors: Yang Gang , Zhang Shen , Wu Ranran , Xun Lina , Hu Fan , Xia Hui
Published: January 2021

A new laser induced ultrasonic transducer (LIU-T) based on photoacoustic effect was presented. Compared with traditional piezoelectric transducers, Liu-T reduced electromagnetic interference and improved the sound pressure signal. Firstly, Liu-T was made and its sound field characteristics were characterized. The experimental results have shown that the sound pressure of this transducer can reach 3.9MPa and the frequency range was 2.5MHz-7.9MHz. Then an experimental platform for magneto-acoustic-electrical tomography(MAET) based on Liu-T was designed and built. Furthermore, B-scan images of abnormal copper plates were obtained by B-scan, which further indicated that LIU-T would play an important role in the field of NDT and biomedical imaging.
Design of Human-Computer Interaction System of Electro-hydraulic Hitch for Hillside Tractors
Authors: Fan Yongkui , Wang Yuanyuan , Zhu Zhongxiang , Lv Meng , Mao Enrong , Zhai Zhiqiang
Published: January 2021

In view of the complex terrain, low level of mechanization and intelligence in hilly region, a human-computer interaction system was designed for electro-hydraulic hitch control system of tractors in hilly region. According to the actual functional requirements of electro-hydraulic hitch control system of tractors in hilly areas, human-computer interaction interface was designed in flash environment, and CAN communication module in Human-computer interaction system was designed in Flash Develop environment. Finally, a hardware test platform of the human-computer interaction system was built in the room for laboratory tests. The results showed that the human-computer interaction system can meet the working requirements of the electro-hydraulic hitch control system of tractors in hilly areas.
Research status of photocatalysis and Thermal insulation building coatings
Authors: Dong Teng , Huang Yunfa , Song Xiaopeng , Lv Hongrui
Published: January 2021

The research status of photocatalytic and thermal insulation coatings at home and abroad was summarized. The different types of photocatalytic coatings were summarized. The factors influencing the photocatalytic coatings, such as the activity of photocatalytic coatings, the load of photocatalytic coatings, and the dispersion process, were expounded. The type and property of insulation coatings and the effects of fillers on the properties of insulation coatings were summarized. At present, the primary problem of photocatalysis and heat preservation and heat insulation building coatings in China is lack of research and development of dispersants and composite materials. The evaluation system of photocatalysis, heat preservation and heat insulation need to be improved. It is of significance for the multi-functional coatings with the performance of luminescent catalytic insulation.
Parametric finite element analysis of Buckling-Restrained Braces
Authors: Liao Xianghui , Zhao Chao , Liu Zengwei
Published: January 2021

The Buckling-Restrained Braces is an excellent seismic energy dissipator. In this paper, the effects of the three core width-thickness ratios, gaps, and constraint ratios of the Buckling-Restrained Braces on the seismic performance of the Buckling-Restrained Braces are studied and modeled and analyzed by ABAQUS The simulation results show that the Buckling-Restrained Braces has the best seismic performance when the width-to-thickness ratio is 10-16; when the gap is 1-2mm, the Buckling-Restrained Braces has the best seismic performance; when the constraint ratio is about 5, the Buckling-Restrained Braces The best seismic performance.
A Study on the Geotechnical Properties of Coal Ash after a Long Term Service Period in Transport Embankment Fill
Authors: Maakoe Tshegofatso , Deng Jianliang , Nepal Dikshit Babu , Simango Annah
Published: January 2021

An extensive range of studies have been conducted on coal-fired power station CCP’s in order to investigate their geotechnical properties for construction of structural fills. Many such researches are based on the performance of fresh ash, however very few have studied their behavior after a long term service period. There exists a rarely discussed CCP ash that was identified in this investigation. Understanding of the long term behavior of CCP’s is essential for motivation of their use in structural fills. This ash was used as an alternative to natural soils for the construction of transport embankment layerworks in countries such as the USA and South Africa. Several decades later after its use in railway embankment fills, the geotechnical properties are evaluated in this study by method of experimental investigation. A series of tests (particle size distribution analysis, specific gravity, compaction and permeability) were carried out with the objective of characterizing the material and determining the shear strength behavior by direct shear test. Test results revealed that the ash is comparable to a granular soil. The direct shear test results revealed that the ash exhibited a significantly high shear strength by the internal friction angle of 51.86°. Furthermore, a reversal and re-shearing of the sample was completed and presented a slightly lowered residual friction angle of 49.37°.
Constitutive Model of TC21 Titanium Alloy Based On BPNN
Authors: Dong Hongbo , Sun Chengtong
Published: January 2021

TC21 alloy is a new two-phase titanium alloy with good comprehensive properties of high strength, toughness and damage tolerance. The isothermal thermal compression deformation test of TC21 titanium alloy is carried out on the Gleeble-3500 thermal simulation test machine. Based on the stress-strain data at different temperatures and strain rates, the constitutive relation model of TC21 alloy was established by using BPNN(Back Propagation Neural Network), which has high prediction and generalization ability, and the predicted flow stress value is very close to the experimental data.
Effect of number of carbon atoms on the electron transport properties of carbon chain-graphene junctions
Authors: Liu Chunmei , Wang Junling
Published: January 2021

Using nonequilibrium Green’s functions in combination with density-functional theory, we investigate the electronic transport properties of carbon chains covalently connected with two bear armchair graphene electrodes. The results show that the transport properties are obviously dependent on the odd and even length chains located between graphene nanoribbons. For graphene nanoribbons connected to the chain with even chains, the negative differential resistance (NDR) is also observed in the I-V curves. The reason is that the even-odd effects are related to the connection structure between electrodes and carbon chains.
Study on Combustion Processes of a Premixed Charge Compression Ignition (PCCI) Engine Fueled with DME/Diesel
Authors: Zhao Yuwei , E Weibo , Niu Tianlin , He Jiangjiang
Published: January 2021

A dimethyl ether (DME) pre-mixing system was installed on a 2105 diesel engine for realizing pre-mixed charge compression ignition combustion mode. Combustion processes of a PCCI engine fueled with DME/diesel under various DME pre-mixing ratios were investigated in this paper. The results showed that the heat release process showed three stages with port induction of DME. As the DME pre-mixing ratio (PR) increased, the peak value of cylinder temperature and pressure raised and the corresponding crank angles advanced. The start of combustion (SOC) moved forward obviously and the duration of combustion extended; the peak value of the pressure rise rate reduced first and then raised. The results in this paper provided a reference for the combustion process optimization of DME/diesel PCCI engine.
Research on transformation design of nuclear support easy to disassemble based on ANSYS Workbench
Authors: Yuan Liang , Feng Tiezhu , Bai Jinchuan , Zhu Qinghai , Kong Xiangyong , Chen Sen , Shen Linshuang
Published: January 2021

The nuclear support, which is used to support pipe or equipment with nuclear safety level, is of great importance for nuclear power plants. In this work, we studied that the door type nuclear support was transformed to disassemble easily by installing bolts. The 3D models of nuclear support before and after transformation were established in ANSYS Workbench software. With the reasonable setting of the contact conditions and boundary, the deformation, stress and natural frequency were calculated in ANSYS Workbench by using the finite element method. The results show that bolted connections will lead to the loss of stiffness of support and natural frequency decrease. The order natural frequency of the support decreases with addition of the thickness of plates and the bolt circle diameter has little effect on global stiffness of the support. The finite element analysis results provide reference for the transformation design and optimization of nuclear support and have practical engineering value.
Design of Car Washing Control System Based on PLC
Authors: Meng Yanan , Hu Xiaoyan , Qi Feng , Chen Zhimin
Published: January 2021

In order to improve the efficiency of car wash and reduce the labor intensity of car washers. According to the process flow of automatic car washing and its characteristics of simple operation, high efficiency, convenience and stable operation, an automatic car washing control system based on PLC is designed, and WinCC configuration software is selected as the upper computer as the man-machine interface design. The simulation results show that the system has strong stability, improves the automation of car washing and meets the actual needs.
Adaptive bit Modulation equalizer
Authors: Dong Yabo , Fan Hong , Ni Lin , Shi Zhaoli , Zhang Ziwei , Fan Hong
Published: January 2021

Multipath effects usually occur in information dissemination, which leads to inter-symbol interference and affects the quality of communication transmission. This paper uses an adaptive equalizer to achieve channel equalization and eliminate inter symbol interference, and develops and verifies it on the FPGA using the ISE suite. Compared with the equalizer output error signal calculated on the MATLAB software, the calculation results of the two platforms are basically the same, which confirms that the design is feasible. The FPGA-designed equalizer implements hardware acceleration and is more suitable for high-speed real-time signal processing. After the data passes through the adaptive bit equalizer, the signal-to-noise ratio is improved, thereby reducing the bit error rate and verifying the relationship between the bit error rate and the signal-to-noise ratio.
Research on Performance of a New-Type Percolation Equipment Used to Extract Effective Medicine Components
Authors: Li Juan , Wu Jun , Wang Xiaochun
Published: January 2021

A new-type of multi-layer percolation equipment was developed and utilized to extract effective component of a certain traditional Chinese medicine. Porosity and penetration rate of 100-mesh medicine powders were measured respectively. Moreover, the superiority of the performance of such equipment over single percolation method and repercolation method was studied where the total solids content in percolated fluid was utilized as the evaluation index. The results show that for 100-mesh medicine powders, porosity and penetration rate of medicine powder layer both decrease with the increase of particle layer height; total solids content in percolated fluid of 100-mesh medicine powders is high, and the new-type multi-layer percolation equipment has the best performance in the extraction of effective component in the medicine.
Propagation invariance and dark hollow structures of sinh-Gaussian beams with small complex parameters
Authors: Zhu Kaicheng , Liang Ruisheng , Yi Yajun , Zhu Jie , Tang Huiqin
Published: January 2021

Through investigating the sinh-Gaussian beam with complex beam parameters, it is the first time to find that such beams can carry vortices and exhibit dark hollow intensity distributions when the complex beam parameters are sufficiently small. A closed-form propagation equation for sinh-Gaussian beams through paraxial ABCD optical systems is derived based on the Collins formula and illustrated with numerical methods. It is shown that the perfect hollow configuration can retain a quite long propagating distance under small complex beam parameters. The analytical discussions affirm the numerical conclusions.
Research on Control Strategy of Z-source Photovoltaic Grid-connected Inverter Based on Sliding Mode Control
Authors: Zheng Yunhong , Zhang Qingquan , Huang Xumin
Published: January 2021

This paper proposes a photovoltaic grid-connected inverter based on a Z-source NPC three-level topology to achieve buck-boost control and improve the transmission efficiency of the system. In view of the instability of the output power of the photovoltaic system, which affects the output of the grid-connected inverter, this paper proposes a dual closed-loop sliding mode control strategy. The DC bus voltage outer loop of this strategy adopts traditional sliding mode control and grid-connected current The inner loop adopts PI control to weaken the system chatter. The anti-interference ability of photovoltaic grid-connected system and harmonic content of grid-connected current were studied through the Matlab/Simulink simulation platform. The results show that the control strategy can effectively improve the robustness of the system and reduce the harmonic content of grid-connected current.
Experimental study on dynamic characteristics of a quasi-zero stiffness vibration isolator
Authors: Liu Yanqi , Song Chunfang , Xu Longlong , Ji Wen
Published: January 2021

In this paper, a kind of quasi-zero stiffness isolator with cam-roller nonlinear spring mechanism as negative stiffness mechanism is studied by sinusoidal sweep frequency experiment, sinusoidal constant frequency experiment and half-sinusoidal impact experiment. The dynamic response characteristics and impact resistance of quasi-zero stiffness isolator are analyzed. The experimental results show that when the excitation is constant, the dynamic response of the quasi-zero stiffness isolation system has a response peak, and the response acceleration and displacement all increase first and then decrease with the increase of frequency. When the excitation amplitude increases, the initial isolation frequency becomes large and the effective isolation bandwidth becomes narrow. For the half-sinusoidal acceleration impact with the pulse width less than 10ms and excitation acceleration less than 13.0g, the quasi-zero stiffness isolation system has excellent isolation and cushioning performance.
Comprehensive Evaluation Model of Power Grid Development Potential Considering Inventory and Incremental Equipment
Authors: Chen Meng , Niu Dongxiao , Geng Shiping , Guo Xiaopeng
Published: January 2021

Reasonable evaluation of the development potential of power grid is an important guarantee for power planning and investment. In this paper, the evaluation index system of power grid development potential is constructed, and based on the operation status of the existing equipment of the power grid, as well as the operation capacity of incremental equipment after the projects under construction and planning are put into operation, the evaluation model of power grid development potential considering the existing / incremental equipment is constructed. Finally, through the verification of Tianjin Power Grid, the index system and method mentioned in this paper are easy to implement and can evaluate the development potential of power grid comprehensively and accurately.
Research on Harmonic Resonance Mitigation Based on Improved Modal Sensitivity Analysis
Authors: Pan Aiqiang , Zhao Jinshuai , Zhang Peng , Pan Ling
Published: January 2021

Among the methods used for mitigation of harmonic resonance, modal analysis theory and modal sensitivity can be used to illuminate the nature and properties of this phenomenon, and are thus widely applied. In this paper, an improved modal sensitivity-based method is proposed to reliably suppress the harmonic resonance. First, we show that the current resonance mitigation schemes that are guided by traditional modal sensitivity are not always robust in some cases. Then, through a theoretical analysis, the roots of the shortcomings of the traditional modal sensitivity are determined. The key factor is that the modal sensitivity of a network component is not always constant but tends to vary with adjustment of the component parameters. Finally, to quantify this sensitivity variation and improve the robustness of the analysis results, a second-order modal sensitivity and a critical index are proposed. The results of the test system indicate that the proposed indexes can accurately show the effects of each network component on the resonance, thus are useful in the design of the corresponding mitigation scheme.
The application of LED illumination and intelligent control in plant factory, a new direction for modern agriculture: A Review
Authors: Arcel Mulowayi Mutombo , Lin Xiaoteng , Huang Jingyi , Wu Jiatong , Zheng Shuhe
Published: January 2021

Because of its cold light source and adjustable spectrum characteristics, light-emitting diode (LED) is widely used in modern agriculture, it can promote the growth and photomorphogenesis of the plant, also can improve yield and quality. Here, we introduce the advantages of LED over traditional light sources, and analyze the effects of different wavelengths of light on phototrophic plants and the ways in which different light detection systems interact in plants. We also analyze the effects of LED illumination on plants, the response of plants to LED illumination systems. In addition, we summarize the typical LED supplement light devices and intelligent control system in the world, and introduce their working methods and advantages respectively. Finally, we look forward to the future development direction and application prospects of LED with the intelligent control and machine in modern agriculture.
Statistical Channel Modelling of Millimetre Waves at 28 GHz and 73 GHz Frequency Signals Using MIMO Antennas
Authors: Ram Nanik , Gao Hongmin , Qin Huanyao , Oo Min Thant , Htun Ye Thet
Published: January 2021

To meet the demand of high spectrum requirement and high-speed wireless communication in future, millimetre waves (mm-Wave) can play a very important role for it. Millimetre waves starting from 30 GHz and ending at 300 GHz can solve the problems like high throughput, faster data rates and capacity. Millimetre waves can help to achieve higher gain by using high dimensional antenna array technology. Beamforming and spatial multiplexing are very famous techniques that can help to increase the gain when antenna arrays are used. Channel modelling plays a very important role in determining the possibility of deploying the wireless communication system. In this research paper, the major challenges regarding the mm-Wave channel modelling are identified and the statistical behaviour of mm-Wave channel at 28GHz and 73 GHz is explained with the help of NYUSIM software. The power loss, power delay profile and path loss, angle of arrival and departure are simulated in this work. These simulations are performed using multiple antennas configuration along with considering the effect of atmospheric impairments like rain, humidity and temperature.
Design of load data simulation source
Authors: Sun Yong , Wang Jianmin , Shi Jiaxiang
Published: January 2021

In the remote sensing satellite system, the main function of the data transmission subsystem is to receive all the data transmitted by the payload subsystem and then transmit it accurately to the data receiving station on the ground. In the absence of satellite payloads, to meet the requirements of the joint remote sensing satellite test link, we studied and designed a load data simulation source that can simultaneously output four channels of continuous data at different rates, and there are two operating modes to choose from. This design adopts Kintex UltraScale series FPGA with configurable Microblaze embedded soft core as the core controller, and the peripheral circuit includes four pieces of 2GB DDR4 memory, power supply and LVDS interface output. The actual test results show that the load data simulation source has high stability and good universality, and can perfectly meet the ground debugging and testing requirements of remote sensing satellite data transmission subsystem.
A Voltage Control Model of Multi-ports DC Transformer
Authors: Wu Hao
Published: January 2021

DC transformer (DCT) is basic and important power conversion equipment in DC distribution network. DC transformer adopts power electronic switches and high-frequency transformer, which can realize power conversion. Multi-ports DCT can connect many different types of power supply or load equipment, and can flexibly control the current, voltage and power flow of multiple ports, which is widely used in DC distribution network. In this paper, the output voltage control model of multi-ports DCT in steady state is established. Combined with the control model, the mechanism of controlling the phase-shift angle to realize the output voltage control is proved mathematically. The correctness of the control model is verified by simulation.
An approach of target photometric measuring for theodolite visible light imaging
Authors: Chen Shengyi , Fan Chaoran , Xu Zhilei , Zhang Feng , Li Xiaoxue
Published: January 2021

Photoelectric theodolite is important optical measurement equipment in pelagic aerospace TT&C systems. The visible light imaging method helps capture significant information of the observed target, photometric information is one of them. To achieve expediently and quickly target photometric measuring, it studies and realizes a measuring method, by using stars in the same field of view as the observed target in this paper. Firstly, it calculates the gray values for target and star by image processing algorithm in the image captured by theodolite. Then magnitude information of the star is obtained by using a star catalogue. Lastly, magnitude of the target is calculated by antitheses method. The approach is implemented to investigate the measuring performance and an experiment is carried out by using images containing at least two stars. The result shows good performance of the proposed method.
Analysis of the influence of the contact mode of the rolling elements of the slewing bearing on its stability
Authors: Deng Biao , Chen Jianwei , Guo Yang , Tang Shengjin
Published: January 2021

The stability of the rolling elements in the slewing bearing is an important factor that determines the smooth rotation of the slewing bearing. The slewing radius of the slewing bearing is large and the load is complicated. In this paper, the contact relationship between the rolling elements and the raceway is established by establishing a slice model of the slewing bearing. Considering the effects of axial load and radial load, respectively, the contact deformation and displacement changes of the rolling elements are analyzed. The simulation results show that the rolling elements of the two-point contact slewing bearing rotate during the load process, and the four-point contact slewing bearing is in the axial direction. Under load, the rolling contact state in the raceway with the raceway is stable without spinning; under radial load, the contact relationship between the rolling element and the four-point contact raceway at this time is essentially two-point contact, but compared to the one used Two-point contact raceway, the rolling elements have better radial stability in the newly designed raceway
Analysis of the influence of raceway structure on contact characteristics of turntable bearing
Authors: Deng Biao , Chen Jianwei , Guo Yang , Tang Shengjin
Published: January 2021

Turntable bearing is widely used in heavy industry. Raceway structure is the most direct factor that affects the contact stress change between raceway and rolling element. Therefore, it is the key to improve the safety of turntable bearing and determine the processing technology reasonably to study the stress distribution of contact area in different raceways. In this paper, the finite element slicing model of rolling element and raceway in turntable bearing is established in ABAQUS. Under the action of axial load and radial load, the distribution characteristics of contact stress of raceway are compared under different raceway structures. The finite element results show that, compared with the two-point contact disc bearing, the rolling element and raceway in four point contact turntable bearing are in four point contact under axial load, The contact stress distribution of raceway is uniform, which is a pair bearing distribution. However, when only considering the radial load, the rolling element and raceway are in two-point contact, and the contact stress distribution characteristics are consistent with those of two-point contact rotary table bearing.
Association of short-term air pollution with systemic inflammatory biomarkers in routine blood test: a longitudinal study
Authors: Di Niu , He Weiliang , Zhang Kaihua , Cui Jian , Chen Jiang , Cheng Jinming , Chu Bao , Li Shanshan , Xie Yinyu , Xiang Hao , Wang Hebo , Chen Gongbo , Guo Yuming
Published: January 2021

The biological mechanisms behind health effects of air pollution have not been well known. Inflammation plays an important role in occurrence and development of a wide range of diseases. In this study, we assessed the effects of short-term exposure to ambient air pollution on systemic inflammatory biomarkers among 12 508 participants who underwent routine physical examination annually at the Hebei General Hospital in Shijiazhuang, China. For each participant, white blood cell count (WBC), lymphocytes, neutrophils and eosinophils were measured for two or three times during September 2016 to December 2018. Daily concentrations of nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3) and particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) were interpolated to each district, where the participants worked. The linear mixed-effects regression with a constrained distributed lag model was applied to examine the associations between air pollution and inflammatory biomarkers during lag 0–14 d. It was observed that WBC, neutrophils and eosinophils [percent change (%Δ) and 95% confidence interval (95%CI)] significantly decreased by −0.07 (−0.11, −0.04), −0.08 (−0.12, −0.03) and −0.15 (−0.25, −0.05) at lag 14 d, associated with per 10 µg m−3 increase in O3. WBC, lymphocytes and eosinophils (%Δ and 95%CI) significantly elevated by 0.08 (0.04, 0.12), 0.16 (0.11, 0.21) and 0.22 (0.10, 0.35) at lag 0 d, associated with per 10 µg m−3 increase in PM2.5. This study reveals short-term effects of air pollution on systemic inflammatory biomarkers in routine blood test, which is helpful for further study to explore the biological mechanisms.
Why scale is vital to plan optimal Nature-Based Solutions for resilient cities
Authors: Hutchins MG , Fletcher D , Hagen-Zanker A , Jia H , Jones L , Li H , Loiselle S , Miller J , Reis S , Seifert-Dähnn I , Wilde V , Xu C-Y , Yang D , Yu J , Yu S
Published: January 2021

A need for multi-functional assessment tools evaluating trade-offs and co-benefits for various types of Nature-Based Solutions (NBS) has been increasingly identified in recent years. Methodologically, concepts for a tool are presented which include quantifying the demand and potential for NBS to enhance ecosystem service (ES) provision, and linking ESs to readily quantifiable and legislatively-relevant environmental quality indicators (EQIs). The objective of tool application is to identify optimal NBS placement across a diverse set of socio-environmental indicators, whilst also incorporating issues of relative location of areas of implementation and benefit accrual. Embedded within the tool is the importance of evaluating outcomes in terms of economic benefits and of sustainable development goals. The concepts are illustrated with simplified examples, relating to the case of implementing urban forestry as an exemplar NBS. By summarising the knowledge base it is demonstrated that benefits of NBS are substantially scale-dependent in two main respects; those of extent and proximity to receptors. Evaluation tools should be capable of quantifying scale-dependence. The substantive importance of these considerations and how their dynamics vary between indicators and services is illustrated graphically through schematic functions. When developed, the tool should be used as a focus for consultation and co-design to pinpoint the size of NBS necessary to achieve a sufficient level of benefit for a particular receptor. This could be measured against target levels of benefit for each indicator, distinguishing between primary intended outcomes and those co-benefits or trade-offs that are secondary or unintended.
Kernels for non interacting fermions via a Green’s function approach with applications to step potentials
Authors: Dean David S , Le Doussal Pierre , Majumdar Satya N , Schehr Grégory , Smith Naftali R
Published: January 2021

The quantum correlations of N non interacting spinless fermions in their ground state can be expressed in terms of a two-point function called the kernel. Here we develop a general and compact method for computing the kernel in a general trapping potential in terms of the Green’s function for the corresponding single particle Schrödinger equation. For smooth potentials in one dimension the method allows a simple alternative derivation of the local density approximation for the density and of the sine kernel in the bulk part of the trap in the large N limit. It also recovers the density and the kernel of the so-called Airy gas at the edge. This method allows the analysis of the quantum correlations in the ground state when the potential has a singular part with a fast variation in space. For the square step barrier of height V
0 in one dimension, we derive explicit expressions for the density and for the kernel. For large Fermi energy μ > V
0 it describes the interpolation between two regions of different densities in a Fermi gas, each described by a different sine kernel. Of particular interest is the critical point of the square well potential when μ = V
0. In this critical case, while there is a macroscopic number of fermions in the lower part of the step potential, there is only a finite O(1) number of fermions on the shoulder, and moreover this number is independent of μ. In particular, the density exhibits an algebraic decay ∼1/x
2, where x is the distance from the jump. Furthermore, we show that the critical behavior around μ = V
0 exhibits universality with respect to the shape of the barrier. This is established (i) by an exact solution for a smooth barrier (the Woods–Saxon potential) and (ii) by establishing a general relation between the large distance behavior of the kernel and the scattering amplitudes of the single-particle wave-function.
Land Suitability for Potential Jatropha Plantation in Malaysia
Authors: Suhana Mokhtar Ernieza , Md Akhir Norshahirah , Ain Mohd Zaki Nurul , Melissa Muharam Farrah , Pradhan Biswajeet , Salihu Lay Usman
Published: January 2021

Malaysia has embarked on several initiatives and policies towards renewable energy for improving quality. Jatropha Curcas is an oil seed-bearing plant, which potentially yields as a source of energy in the form of biodiesel. However, research on the determination of the potentially suitable area of Jatropha plant can be allocated still limited. This study aims to carry out a land suitability study on the Jatropha plantation using the geospatial technique such as Geographical Information System (GIS) and remote sensing. To achieve the aim, the objectives of this study are to i) determine significant weightage of parameters for Jatropha plantation and ii) identify the suitable location Jatropha plantation. The study area is carried out at peninsular Malaysia, and five (5) variables such as rainfall, temperature, land-use, soil and elevation data were used to achieve the analysis. The analytical hierarchy process (AHP), in the combination of Geographical Information System (GIS) methods, was applied to compute the weightage of the selected criteria, which is in geospatial data types. A map of the potential Jatropha location was generated using the criteria weightage. This study can help the cultivation of Jatropha in suitable areas and may reduce the burden on fossil fuels. It can assist smallholder-based initiatives to promote Jatropha cultivation on farmer-owned to enhance their living circumstances.
Assessment of Coastal Altimetry Data in the South China Sea using Multiple Frequency Approaches
Authors: Mohd Hairy Ansar Andi , Hassan Md Din Ami , Idris Khairulnizam M , Hanif Hamden Mohammad , Nizam Uti Mat , Liew Jeng U
Published: January 2021

With a coastline length extending over 13,000 km, including the Malaysia region, the South China Sea presents a challenge to retrieve high quality data along the coastal area especially the sea level anomaly and significant wave height. Currently, coastal altimetry is still facing some issues especially when using the low frequency data such as data lacking near the coast, questionable data accuracy since the altimeter footprint contaminated with the land and less coverage of data from the installed ground truth data. This study aims to assess the coastal altimetry data of sea level and significant wave height in the South China Sea using low and high frequency approaches. This study involved deriving data from sea level anomaly (SLA) and significant wave height (SWH) through the use of Prototype for Expertise on AltiKa for Coastal, Hydrology and Ice (PEACHI) for high frequency and Radar Altimeter Database System (RADS) for low frequency of altimetry and ground truth station which is from tide gauge and Acoustic Wave and Current Profiler (AWAC). Comparison between altimetry and ground truth data has been made in order to validate the significant agreement between them. The validation of the data is to evaluate both types of frequencies with respect to the coastal distance. Consequently, the high frequency results for coastal results with a root mean square reliable ±0.14 metre level for the sea level anomaly (SLA) and ±0.18 metre level for significant wave height (SWH) are more reliable. PEACHI distance-to-coast data obtained a sufficient standard residual deviation ranging from 0 cm to 2.87 cm compared to RADS altimetry ranging from 0.08 cm to 14.20 cm. The findings of this study indicate that the coastal altimetry data benefit coastal development, coastal defence, monitoring and tourism by various related agencies.
River engineering for flooding characteristics in the upper-stream part of Bengawan Solo Sub-watershed
Authors: Syaifurahman A , Nurzain D A , Prastica R M S
Published: January 2021

Flooding in Surakarta, which is located in the upper-stream part of Bengawan Solo Sub-watershed, needs further investigation to reduce the disaster impact. This study conducted a flood analysis in the sub-watershed to find out how much the impact of flooding on the river flow that has the risk of flooding due to the overflow of water and extreme weather. The research aims to investigate the hydraulic characteristics of the river in the sub-watershed towards the flooding and identifies the river engineering strategy for mitigation. Based on the results of the hydrological and hydraulics analysis, the existing channel was flooded due to being unable to accommodate the return flood discharge, so a new channel design was needed. The design of new channels is done by widening and being able to deepen the channel. The result of the analysis of the new channel indicates that the capacity could accommodate a discharge capacity of 8915.93 m3/second with its river bank safety factor value of 3.14. In conclusion, river engineering compromises good strategy for flood mitigation in the study area.
The condition assessment scheme for ancient timber structure using material and deformation analysis
Authors: Juan W , Putri A D
Published: January 2021

A condition assessment is one of a crucial part of ancient structure, in which this phase will be the reference before giving a treatment and maintenance. The initial step after the visual inspection conducted will be the material properties analysis to the structure using the Non-Destructive Test (NDT). Furthermore, the deformation analysis will be part of the onsite assessment for long term analysis of a structure. The deformation analysis part has a purpose of determining the movement. This paper will take one of Ancient timber structure as a study case. The building consists of a complex ancient timber structure representing mostly the characteristic of ancient buildings in Asia. Overall, it will focus on discussing the part of the general condition assessment scheme. The general overview of the process of on-site tests and deformation measurement is shown to represent the general need for assessing an ancient timber structure. As a result, the deformation analysis of the structure can the alternative for the next phase as reference for structural damage solutions.
Development of ecosystem health index in rural areas of Java Island: Preliminary results
Authors: Yuwono A S , Wardiatno Y , Widyastuti R , Wulandari D , Natali M
Published: January 2021

The assessment of ecosystem health in Indonesia is currently being conducted poorly since no national guidance standard. This study aimed to formulate a quantitative system to justify the rural ecosystem quality with six indicators, i.e. air pollution index (API), water pollution index (WPI), forest coverage index (FCI), biodiversity index, public health and environmental health. This research is a type of basic and applied research at the same time, where applied research lies in the implementation part of the ecosystem health index. Environmental conditions at rural areas of Java Island (Regencies of Pandeglang, Bandung, Temanggung, Magetan and Bangkalan) was evaluated. Secondary data collection from local environmental management and health authorities was conducted in March-May 2019. The data is expressed into indices with a value of each components ranging from 0 to 100. The ecosystem quality of Bandung Regency, Temanggung Regency, Bangkalan Regency, Magetan Regency quantitatively showing numbers of 67.03, 80.68, 81.76 and 78.66. The four values exceeded the national standard (IKLH, Indeks Kesehatan Lingkungan Hidup) in 2017, i.e. 66.46. It indicates that the ecosystem quality of these four regencies is generally professionally managed. Meanwhile, Pandeglang Regency shows the number of 65.22, which is below the national standard of IKLH.
Measurement of PM10 concentration using hybrid cyclone separator and particle counter
Authors: Purbakawaca R , Yuwono A S , Saptomo S K , Seminar K B , Subrata I D M , Rahmat M , Alatas H
Published: January 2021

Commercial air quality monitoring systems can measure PM10 very precisely and accurately but are expensive to procure and maintain. The research objective was to design a portable, easy-to-handle, real-time PM10 monitor using a particle counter PPD42NS, cyclone separator, vacuum pump, temperature, relative humidity, and air pressure sensors types BMP085 and DHT22. A comparative study of meteorological factors between Vantage Pro 2 and the BMP085 and DHT22 sensors shows a positive linear correlation. The sensor was used to correct the air sample flow rate in the PM10 concentration formulation. The air sample flow rate is stabilized at 0.7 L min−1 so that the cyclone separator can work optimally. The particle size analyzer (PSA) analysis results show that the cyclone separator can separate particles less than ten microns in size at locations with low, medium, and high PM10 conditions. PM10 obtained from the separation process was measured with a PPD42NS particle counter and was successfully converted into mass concentration using a mathematical formula on the microcontroller. The PM10 monitoring system was tested for 24 hours in the wood processing area with a concentration of PM10 278.5 μg cm−3, which was categorized as unhealthy.