Zun-Di Huang¹, Zhen-Bin Zhou^1,2,3, Ning Chang¹, Zheng-Wei Chen^2,3,*, Su-Mei Wang^2,3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 975-996, 2024, DOI:10.32604/cmes.2024.047664

Abstract The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics. Therefore, this paper uses an improved delayed detached eddy simulation (IDDES) method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds. The effects of marshaling lengths (varying from 3-car to 8-car groups) on the train’s aerodynamic performance, surface pressure, and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes (N-S) equations. The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle… More > Graphic Abstract

Kai Wang¹, Biao He^2,*, Pijush Samui³, Jian Zhou⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 229-253, 2024, DOI:10.32604/cmes.2024.047569

Abstract Rock bursts represent a formidable challenge in underground engineering, posing substantial risks to both infrastructure and human safety. These sudden and violent failures of rock masses are characterized by the rapid release of accumulated stress within the rock, leading to severe seismic events and structural damage. Therefore, the development of reliable prediction models for rock bursts is paramount to mitigating these hazards. This study aims to propose a tree-based model—a Light Gradient Boosting Machine (LightGBM)—to predict the intensity of rock bursts in underground engineering. 322 actual rock burst cases are collected to constitute an exhaustive rock burst dataset, which serves… More >

Junjie Zhao, Diyuan Li^*, Jingtai Jiang, Pingkuang Luo

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 275-304, 2024, DOI:10.32604/cmes.2024.046960

Abstract Traditional laboratory tests for measuring rock uniaxial compressive strength (UCS) are tedious and time-consuming. There is a pressing need for more effective methods to determine rock UCS, especially in deep mining environments under high in-situ stress. Thus, this study aims to develop an advanced model for predicting the UCS of rock material in deep mining environments by combining three boosting-based machine learning methods with four optimization algorithms. For this purpose, the Lead-Zinc mine in Southwest China is considered as the case study. Rock density, P-wave velocity, and point load strength index are used as input variables, and UCS is regarded… More > Graphic Abstract

Jiaqi Wu¹, Li Zhuo^1,*, Jianliang Pei¹, Yao Li², Hongqiang Xie¹, Jiaming Wu¹, Huaizhong Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 621-645, 2024, DOI:10.32604/cmes.2024.046398

Abstract The surrounding geological conditions and supporting structures of underground engineering are often updated during construction, and these updates require repeated numerical modeling. To improve the numerical modeling efficiency of underground engineering, a modularized and parametric modeling cloud server is developed by using Python codes. The basic framework of the cloud server is as follows: input the modeling parameters into the web platform, implement Rhino software and FLAC^3D software to model and run simulations in the cloud server, and return the simulation results to the web platform. The modeling program can automatically generate instructions that can run the modeling process in… More >

Susi Susi^1,2,*, Makhmudun Ainuri^3,*, Wagiman Wagiman³, Mohammad Affan Fajar Falah³

Journal of Renewable Materials, Vol.12, No.3, pp. 513-537, 2024, DOI:10.32604/jrm.2024.045586

Abstract Microcrystalline cellulose (MCC) is one of the cellulose derivatives produced as a result of the depolymerization of a part of cellulose to achieve high crystallinity. When implemented in other polymers, high crystallinity correlates with greater strength and stiffnes, but it can reduce the water-holding capacity. The acid concentration and hydrolysis time will affect the acquisition of crystallinity and water absorption capacity, both of which have significance as properties of hydrogel filler. The study aimed to evaluate the properties and select the MCC generated from varying the proportion of hydrochloric acid (HCl) and the appropriate hydrolysis time as a filler for… More > Graphic Abstract

R. VENKATESAN^*, S. R. DARSON IMMANUEL JOHN, N. RAJESWARI

Journal of Polymer Materials, Vol.36, No.3, pp. 261-273, 2019, DOI:10.32381/JPM.2019.36.03.6

Abstract Nanocomposite films of chitosan (CH) incorporated with different wt. % of the polyoligomericsilsesquioxane (POSS) were prepared by solution casting. The thermal, mechanical, morphological and antimicrobial properties of the nanocomposites were examined. TGA analyses of the nanocomposites indicate that the filler enables the enhancement of thermal stability of chitosan. The tensile strength of the nanocomposite films is enhanced (10.9 MPa for neat chitosan to 24.0MPa for 5wt. % filled chitosan) by the addition of POSS while the elongation at break is reduced. The nanocomposite films exhibited excellent antimicrobial activity against both gram positive and gram negative bacteria. This activity increases with… More >

ASIS K. MANDAL¹, DEBABRATA CHAKRABORTY², MAHUYA DAS³, SAMIR K SIDDHANTA^4,*

Journal of Polymer Materials, Vol.38, No.1-2, pp. 21-34, 2021, DOI:10.32381/JPM.2021.38.1-2.3

Abstract Elastomeric chlorosulfonated polyethylene (Hypalon) and thermoplastic polypropylene (PP) based thermoplastic Vulcanizates (TPVs) were prepared in presence of different doses of partial methyl ester of styrene-maleic anhydride copolymer (PMES-MA) as compatibilizer employing dynamic vulcanization technique. The mechanical analysis of the prepared TPVs exhibited significant improvements in stress at 25% modulus, ultimate tensile strength (UTS), and hardness values. FTIR studies revealed that a chemical interaction had taken place between hypalon and compatibilizer during the process of dynamic vulcanization which led to an enhancement of interfacial adhesion between them. The two-phase morphologies were clearly observed by scanning electron microscopic studies. The Tg values… More >

SHOGO TAKASUKA^1,*, TATSUHIRO TAKAHASHI¹

Journal of Polymer Materials, Vol.38, No.1-2, pp. 1-10, 2021, DOI:10.32381/JPM.2021.38.1-2.1

Abstract The effects of compounds containing oxazoline groups and the presence of maleic anhydridegrafted polypropylene (PP-g-MAH) on the spectral, morphological, and tensile properties of polypropylene (PP)/liquid crystalline polymer (LCP) blends were investigated. A wholly aromatic LCP having a low melting point which was copolyester, namely AL-7000 have been used, because thermal decomposition of PP and compatibilizer must be prevented.Compression molding was selected as the molding method because it allows molding with a small amount of sample. The binary blends of PP and LCP showed a degradation of tensile properties compared to pure PP. However, the addition of 2,2'-bis(2-oxazoline) and PP-g-MAH as… More >

DENIZ AKIN SAHBAZ^1,*, BETUL TURP KAYA²

Journal of Polymer Materials, Vol.38, No.3-4, pp. 247-256, 2021, DOI:10.32381/JPM.2021.38.3-4.6

Abstract The objective of this study is to develop chitosan-based films containing Hypericum perforatum L. and/or Citrus limon L. oils and to investigate their suitability as novel wound dressing materials. The morphology of the chitosan-based films were observed by means of employing the scanning electron microscopy (SEM) and the chemical structure characterization was performed via Fourier Transform Infrared Spectroscopy (FTIR). Hypericum perforatum L. and/or Citrus limon L. were successfully incorporated to the chitosan films. Antibacterial, swelling, and mechanical properties of these films were investigated. The antibacterial property was enhanced by incorporating Hypericum perforatum L. and Citrus limon L. oils in the… More >

MUHAMAD SOFFI BIN MANDA^1,2, MOHD RUZAIMI BIN MAT REJAB¹, SHUKUR ABU HASSAN^3,4, MAT UZIR BIN WAHIT^3,4, JOSEPH SELVI BINOJ^5,*, BRIGHT BRAILSON MANSINGH⁶, SITI SAFARAH BINTI AMIRNUDDIN³, ALAMRY ALI⁷, KHENG LIM GOH^8,9, DIDIK NURHADIYANTO¹⁰

Journal of Polymer Materials, Vol.39, No.3-4, pp. 241-253, 2022, DOI:10.32381/JPM.2022.39.3-4.5

Abstract This study investigates the potential of Tin Slag Polymer Concrete (TSPC) strengthening through confinement using basalt fiber reinforced polymer (BFRP) and aramid fiber reinforced polymer (AFRP) confinement. TSPC short cylindrical column samples have been wrapped with BFRP and AFRP in a single layer (30 mm overlap) using Sikadur-330 epoxy and final samples were coded as TSPC-UC, TSPC-BF and TSPC-AF for unconfined, BFRP and AFRP for confined respectively. After curing for 30 days at room temperature, compressive test has been performed to know the strength, modulus, strain, fracture energy and failure modes of unconfined and confined TSPC. Test result shows that… More >