bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative study of demineralized coals by IR spectroscopy
Authors: Fedorova N I , Malysheva V Yu , Mikhaylova E S , Ismagilov Z R 
Published: February 2021

Abstract
The article presents the results of a study of the influence of ash content of coal on the qualitative characteristics of their IR spectra. Comparative analysis of the IR spectra of the initial and demineralized bituminous coals showed that the mineral components present in their composition in the form of silicates, clay minerals, and carbonates limit the resolution of the method in the range <970 cm-1, since their characteristic peaks are superimposed on the lines from organic matter of coal. Treatment of coals with mineral acids leads to a decrease in their ash content by 5-8 times, which results in an increase in the content of conventional organic matter in demineralized samples. This, in turn, leads to an increase in the optical density of absorption bands in the entire range of the study and, therefore, allows them to be identified more reliably.
Basic technologies of direct catalytic oxidation of H2S to sulfur
Authors: Khairulin S.R. , Kerzhentsev M.A. , Salnikov A.V. , Ismagilov Z.R. 
Published: February 2021

Abstract
A brief analysis of the existing technical solutions for the purification of gases from hydrogen sulfide is carried out. The huge volume of such emissions and the lack of ready-made solutions for mini-gas processing plants and mini-refineries determine the relevance of the development of environmentally reliable, efficient and compact technologies to solve this problem. The main results of tests of technologies and installations developed at the Institute of Catalysis of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk) based on the direct catalytic oxidation of hydrogen sulfide are presented.
Pilot tests of low-temperature catalytic reduction of sulfur dioxide in realistic conditions of sulfur recovery unit at copper plant of Polar Division of PSC “Norilsk Nickel”
Authors: Khairulin S.R. , Yashnik S.A. , Salnikov A.V. , Ismagilov Z.R. 
Published: February 2021

Abstract
Pilot tests of low-temperature catalytic reduction of sulfur dioxide in realistic conditions (technological gases of Vanyukov furnace) of sulfur recovery unit at Copper Plant of Polar Division of JSC “Norilsk Nickel” have been carried out. It has been demonstrated that the developed CuCr catalyst provides sulfur recovery not less than 90% at GHSV-2000 h−1 in a temperature range 200-260°C.
Study of bitumoids extracted from O-alkylated brown coal
Authors: Shpakodraev K. M. , Zherebtsov S.I. , Malyshenko N.V. , Ismagilov Z. R. 
Published: February 2021

Abstract
The component composition of bitumen obtained from brown coal of grade 1B of the Tyulganskoye deposit of the South Ural basin was investigated using destructive O-alkylation with n-butanol. The positive effect of alkylating treatment on the bitumen yield is shown. A number of individual compounds were identified by gas chromatography-mass spectrometry in the composition of the studied bitumoids: n-Tetracosanol-1, Docosanoic acid, Tricosanoic acid, Podocarpa-5,8,11,13-tetraen-7-one, 13-hydroxy-14-isopropyl, etc. Among the identified substances, biologically active substances are present in significant concentrations: β-Sitosterol, gamma-Tocopherol, Sugiol, Behenic alcohol, etc.
A model to predict the elastic field radiated by a magnetostrictive patch transducer into an omnidirectional waveguide
Authors: Cousin G , Lhémery A , Grondel S 
Published: February 2021

Abstract
Magnetostrictive patch transducers (MPT) can be used as sources or sensors of elastic guided waves in non-destructive testing and structural health monitoring methods. A tool for simulating them is under development to help designing optimal MPT for a given application. It requires the prior accurate modelling of transduction phenomena involved in such patches and of the GW fields they generate. A MPT is made of a thin magnetostrictive strip under a static magnetic field, glued to the waveguide under examination and excited by an alternative current circulating in a coil. In the strip where they take place, transduction phenomena are similar to those generated by an electro-magnetic acoustic transducer (EMAT) in a ferromagnetic medium. They involve magnetostrictive strain, magnetization force and surface traction and Lorentz force (Clausse et al. 2017 J. Phys.: Conf. Ser.
797 102004), which can be transformed into equivalent surface stresses at the outer surface of the strip. A matrix model is developed to propagate the equivalent stresses from this outer surface to that of the waveguide. Once equivalent stress distributions are computed at this latter surface, a model (Barras et al. 2020 Ultrasonics
103 1060782) is used to predict the MPT radiation into the waveguide. Overall, the chaining of these models constitutes a semi-analytical multi-physics model for GW radiation by MPT of high computing efficiency.
Evidence of the formation of the shock scattering induced violent cavitation cluster during boiling histotripsy insonation: A numerical case study
Authors: Pahk K J 
Published: February 2021

Abstract
Boiling histotripsy is a promising noninvasive ultrasonic technique that can be used to mechanically destroy solid tumours. In boiling histotripsy, the formations and dynamics of a boiling vapour bubble and cavitation clouds contribute towards mechanical tissue fractionation. Whilst a number of numerical and experimental studies have been performed to examine and understand the evolution of a boiling bubble at the HIFU focus in a viscoelastic medium, little is known about the subsequent generation of cavitation clouds that form in between the boiling bubble and the HIFU transducer during boiling histotripsy insonation. Previous experimental observations suggest that the shock scattering by a boiling bubble may play a significant role in producing cavitation clouds. The main objective of the present study is, therefore, to investigate the relationship between the shock scattering phenomenon and the occurrence of cavitation clouds through (a) performing a numerical simulation of nonlinear wave propagation with the presence of a bubble at the HIFU focus and (b) comparing with the previous high speed camera observations of a cavitation cluster formation. The size of a bubble (i.e., 95.7, 128.1 and 258 μm in diameter) as well as the HIFU exposure conditions (i.e., a driving frequency of 1.1 MHz, peak positive and negative pressures of 68.4 MPa and −13.9 MPa) used in the simulations were obtained from the previous boiling histotripsy experiments conducted with a tissue gel phantom. The numerical results presented in this study clearly demonstrate that the shock scattering is the main cause of the creation of a cavitation cluster in boiling histotripsy.
Machine learning algorithms for the prediction of the mechanical properties of railways’ rail pads
Authors: Ferreño D , Sainz-Aja J A , Carrascal I A , Cuartas M , Pombo J , Casado J A , Diego S 
Published: February 2021

Abstract
Train operations generate high impact and fatigue loads that degrade the rail infrastructure and vehicle components. Rail pads are installed between the rails and the sleepers to damp the transmission of vibrations and noise and to provide flexibility to the track. These components play a crucial role to maximize the durability of railway assets and to minimize the maintenance costs. The non-linear mechanical response of this type of materials make it extremely difficult to estimate their mechanical properties, such as the dynamic stiffness. In this work, several machine learning algorithms were used to determine the dynamic stiffness of pads depending on their in-service conditions (temperature, frequency, axle-load and toe-load). 720 experimental tests were performed under different realistic operating conditions; this information was used for the training, validation and testing of the algorithms. It was observed that the optimal algorithm was gradient boosting for EPDM (R2 of 0.995 and mean absolute percentage error of 5.08% in test dataset), TPE (0.994 and 2.32%) and EVA (0.968 and 4.91%) pads. This algorithm was implemented in an application, developed on Microsoft. Net platform, that provides the dynamic stiffness of the pads characterized in this study as function of material, temperature, frequency, axle-load and toe-load.
Development of recycled polypropylene-based sustainable composites with recycled carbon fibre/Kenaf fibre hybrid reinforcements
Authors: Cong X Y , Pierce R , Liu X L 
Published: February 2021

AbstractRecycled carbon fibre (RCF) and Kenaf fibre (KF) have been used as reinforcement materials in combination with recycled polypropylene (RPP) matrix to manufacture a sustainable composite. Maleic anhydride grafted polypropylene (MAPP) has also been used as a compatibilizer to modify the interface between fibres and matrix composites, resulting in improved composite strength and thermal resistance. After modified with MAPP, the recycled carbon fibre was combined with KF fiber to improve the KF/RPP composite properties such as mechanical and thermal stability. The results were indicated that the mechanical properties of RCF/RPP composite was improved with increasing of MAPP when MAPP added 8 Wt. %, these reached a Maximum of 77.6 MPa and 271.4 MPa, respectively. When the RCF combined with the KF hybrid composite, the mechanical strength of the hybrid composite was improved with the amount of RCF. The DSC results showed that the MAPP could reduce the Tc of RPP and increase the crystallization degree. The hybrid composite presented that the crystallization degree was increased with the increment of RCF content. The DMA results showed that the RCF can influence the β translation of RPP.
The growth mechanism of zinc oxide micro-rods via vapor-phase method
Authors: Pan J M , Yu Y , Liu J T , Wang L N 
Published: February 2021

Abstract
Two different ZnO micro-structures were deposited by a Chemical Vapour Deposited method in a small quartz tube. The micro-rods and micro-wires were found on the edge of the tube respectivly. The morphology and structural properties were texted by scanning electronic microscopy technique and X-ray diffraction. The results shows that the micro-rods have typical hexagonal wurtzite structure without any defect and the micro-wires have two types, the single ZnO crystal and the double-like one. The X-ray diffraction gives some information through the intense 002 peak which means the samples have a great wurtzite structure and grown up along the c-axis. The mechanism of the two samples also discussed, it is in relation to the substrate temperature and the concentration of the mixed gas.
Research on the influence of humid heat environment on the mechanical properties of multilayer composite structure
Authors: Wang W C , Yang H W , Li N , Kang Y S 
Published: February 2021

Abstract
For resin-based composite materials, the hot and humid environment has a very obvious impact on its performance. Moisture can penetrate into the composite material through diffusion and capillary action, which causes the resin matrix with plasticization, swelling and hydrolysis, and swelling and infiltration of liquid will lead to micro-stress inside the material. Thus, the polymer macromolecular chain will stretche or even break, and it can lead to the weakening of the interface properties of the resin and the fiber, which in turn leads to fluctuations in the mechanical properties of the composite material. In this paper, we carried out damp and heat tests on multilayer composite structures to study the effects of different temperature and humidity environments on the physical and chemical properties and mechanical properties of composite materials. The law of moisture absorption characteristics of composite materials is clarified, and the moisture absorption in the initial stage of moisture absorption is proportional to the moisture absorption time t1/2. With time increasing, the moisture absorption gradually tends to balance, and the higher are the damp and heat conditions, the greater the moisture absorption of the composite material will be. The moisture absorption is between 0.13% and 0.78% with different damp and heat environments. The chemical structure of the composite material itself has not changed significantly, and the damp-heat effect will induce the destruction of the fiber-matrix interface and the expansion of cracks along the pores, which weakens the bonding strength of the interface. As a result, the moisture makes the transverse performance and shear performance of the composite material greatly reducing, but has little effect on the longitudinal performance.
Mechanical properties, permeability and freeze-thaw durability of low sand rate pervious concrete
Authors: Liu H B , Zhou S , Wei H B , Li W J , Xiu R , Zhu B 
Published: February 2021

Abstract
To improve the mechanical properties, permeability and freeze-thaw resistance of pervious concrete (PC), make the gradation more reasonable, a kind of low sand rate pervious concrete (SPC) was prepared in this study. The sand was used to replace coarse aggregate with equal volume method. The effects of sand replacement rate (0%, 5%, 10% and 15%) on the compressive strength, flexural strength, effective porosity, permeability coefficient and compressive strength loss (under the freeze-thaw cycle) of SPC were studied. The results showed that the compressive strength and flexural strength increased first and then decreased with the increase of sand replacement rate, while the effective porosity and permeability coefficient showed the opposite trend. Moreover, the compressive strength of SPC with different sand replacement rate gradually decreased as the freeze-thaw cycles test continued. After 100 freeze-thaw cycles, the compressive strength loss rate of SPC with 5% sand content is the lowest and is 6.79% lower than that control group (0% content), which indicated that the addition of sand could significantly enhance the freeze-thaw durability of SPC. Based on the experimental results, the recommended sand replacement rate is 5%.
Thermal analysis of cylindrical molds using thermoplastic composite during robotic fiber placement
Authors: Liu X L , Han Z Y , Zhao Z Y , Sun S Z 
Published: February 2021

Abstract
Thermoplastic composites have gradually become a hotspot due to its low manufacturing cost and good weld ability. In this study, to realize the placement of the thermoplastic composite material carbon fiber/polyether ether ketone (CF/PEEK), the consolidation roller of the existing thermoplastic composite placement head is optimized. The process simulation analysis of the thermoplastic composite material is carried out. A two-dimensional heat transfer model of the thermoplastic prepreg laying process is established in ANSYS. Transient thermal analysis is carried out using the life and death unit technology. The optimum machining parameters are obtained through analyzing the influence of mold temperature, laying speed, and heating temperature on the temperature field of the first layer in curved surface laying.
The mode II delamination toughness of arc unidirectional fiber-reinforced composites with ENF test
Authors: Kang Y S , Zhang X Z , Wang L M , Jiang C 
Published: February 2021

Abstract
To obtain the mode II delamination toughness (the energy release rate GIIC) of arc unidirectional fiber-reinforced composites, the end notched flexure (ENF) test with arc specimen was used to study. In terms of theory, the formulas of compliance and GIIC for Arc-ENF specimen were derived by using energy method and Irwin-Kies formula, and the crack length correction and friction coefficient were respectively introduced to correct these formulas, with the verification by the numerical simulation. As the ENF test, the compliance curve of the Arc-ENF specimen was recorded under the condition of the constant loading speed, and the crack tip position was determined by the strain diagram of the specimen in 1-3 plane with the optical strain gauge. Finally, the friction coefficient and the GIIC of the Arc-ENF specimen in the ENF test were determined using the corrected formulas, the numerical simulation method and the ENF test data.
Preparation and characterization of 6-O-caffeic acid chitosan
Authors: Chen W P , Huang D J , Hu Z , Zhuang Y L , Lu S T 
Published: February 2021

Abstract
The modified chitosan retains the excellent properties of chitosan and can broaden its application. In this paper, an approach of protection-deprotection was used to synthesize 6-O-caffeic acid chitosan with chitosan as the raw material. Firstly, the free amino group on the 2-position carbon of chitosan was protected by phthaloylation, and then the -OH of 6-position carbon of chitosan reacted with caffeic acid by ester condensation. Finally, in the presence of hydrazine hydrate, the amino group was deprotected to form 6-O-caffeic acid chitosan. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) characterized the structures of the intermediates and products. The results showed that 6-O-caffeic acid chitosan was successfully obtained. Thermogravimetric analysis indicated that 6-O-caffeic acid chitosan had better thermo-stability than chitosan in nitrogen. This will expand the application of chitosan in vaious fields.
Influence Analysis of Large-area PHC Pipe Pile Construction on the Surrounding Environment in Deep Silt Site
Authors: Zheng Zhongliang , Ding Jihui , Li Xiaoqing , Su Shuyu , Zhang Cong 
Published: February 2021

Abstract
There are a large number of deep and thick soft soil foundations along the river and coastal areas. PHC pipe piles have become one of the foundation treatment methods widely used in soft soil foundations. Taking the construction of a pile foundation project in Wenzhou as an example, the thickness of the dredger fill and silt at the site is 27.20∼33.60m, and the impact of large-area pile group construction on the surrounding environment is discussed. The results show that: (1) The load imposed on the pile top and the pile sinking depth during the construction of the foundation pile increase according to an exponential function. (2) The direction of horizontal soil squeezing deformation around the field is related to the position of the measuring point. The corner range is small and the middle range is larger, but the direction of maximum displacement is basically along the shortest line between the pile position and the measuring point. (3) The vertical direction of the measuring point varies greatly with the construction time and pile position, and the uplift and settlement appear repeatedly. The monitoring results can provide a reference for the construction of similar projects.
The test effect evaluation of distributed optical fiber sensing technology applied to stress test of bored pile
Authors: Zhang Long , Liu Zhenghong , Yu Yongtang , Zheng Jianguo , Huang Xiaowei , Chen Xiaosan 
Published: February 2021

Abstract
The application of distributed optical fiber sensing technology to stress test of bored pile is a kind of line measurement method developed in recent years. It has the advantages of more measuring points and stronger anti-interference, but its test effect is rarely compared with other methods in practical engineering. In order to evaluate the test effect of distributed optical fiber sensing technology, the optical fiber and sliding micrometer tube were embedded at the same time during the construction of test pile, and then the static load test of pile was carried out to compare the test results of the two. The test results show that the strain distribution of the pile obtained by the distributed optical fiber sensing technology and the sliding micrometer method are the same, and the maximum strain difference between them is about 100 με. The distributed optical fiber sensing technology can better reflect the detailed deformation of the pile.
Analysis and research on the bearing capacity of geocell reinforced cushion subgrade in liyu expressway
Authors: Wang Xiaoming , Zhou Yongxing , Feng Jiaqing , Pradhan Rupesh , Liu Guofeng 
Published: February 2021

Abstract
This paper takes the filling roadbed of the Lipu-Yulin Expressway (Liyu Expressway) project in the Guangxi Zhuang Autonomous Region as the backup project. Numerical simulation research is conducted by employing the general finite-element analysis software ABAQUS. The three-dimensional numerical models of the unreinforced soil embankment and reinforced embankment are formulated and the subgrade’s ultimate bearing capacity is calculated and solved by the elastoplastic finite element method. Effects of planar and three-dimensional reinforcement, i.e., geotextile and geocell, on the ultimate bearing capacity of the foundation are calculated and analysed. Simultaneously, the strength and deformation characteristics of geocells and geotextiles under embankment loads are studied. Research results show that the enhanced bearing capacity of geocell-reinforced foundation in this paper is increased by about 30%, which is greater than that of the planar reinforced material. This research results in this paper provide reference and theoretical basis for designing and analysing geocell-reinforced embankment in actual engineering practices.
Research on the influence of the intercalated rock stress by the approach of three tunnels
Authors: Wu Jinlin , Gong Lun , Zhou Shangjin , Gou Mingzhong , Huang Jianhua 
Published: February 2021

Abstract
The article relies on the Guang-Xing section of the southern section of the third phase of Chengdu Metro Line 1 to cross the Cheng-Hua Railway. The change of the stress with the approaching is analyzed. Study the stress change law of the intercalated rock under the change of the distance and angle: when the distance decreases, the maximum principal stress increases more obviously, which shows that the smaller distance, the easier the damage of intercalated rock. The stress state of the rock at different angles is that it is safer to overpassing and undercrossing, the horizontal approach is the most dangerous, and the other angles tend to be between the two. Through three-dimensional numerical simulation, the influence of the excavation process and construction method is analyzed, and it is found that the change of the secondary stress on the sandwiched rock by the mining method is relatively larger than that of the shield method. This makes the surrounding rock disturbance relatively large, resulting in the weakening of the sandwiched rock, which is directly manifested as the increase of the subgrade displacement.
Constitutive model of confined concrete with stirrups by acid rain erosion
Authors: Yue ZHENG , Shansuo ZHENG , Xiaohang LIU 
Published: February 2021

Abstract
In order to study the influence of stirrup corrosion level on the peak stress, peak strain, ultimate strain and shape of stress-strain curve of the confined concrete, 15 reinforced concrete prism specimens were subjected to acid rain erosion by artificial climate simulation technique followed by axial pressure tests. Based on Mander’s model and the existing research results, the calculation formulas of the peak stress f’
cco, peak strain £cco, ultimate strain ε
cco, ultimate strain ε
cu0 and shape factor r of the uncorroded specimens are determined. The factor calculation formulas for peak stress, peak strain, ultimate strain and shape factor of corroded specimens is developed by regression analysis of test data, respectively, and then the constitutive model of confined concrete by acid rain erosion is established. By comparing the simulation results with the experimental data, it can be found that all the peak stress, peak strain, ultimate strain and stress-strain curves shape of the specimens obtained by the proposed method are in good agreement with the experimental data. Thus the constitutive mode for confined concrete established in this paper can accurately reflect the mechanical performance of RC prism specimen by acid rain erosion, indicating its adaptiveness for estimating the residual bearing capacity and the seismic performance of RC structure under the acid rain environment.