Jipeng Xie^1,2, Guolai Yang^1,*, Liqun Wang¹, Lei Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 793-819, 2024, DOI:10.32604/cmes.2024.048174

Abstract To enhance the comprehensive performance of artillery internal ballistics—encompassing power, accuracy, and service life—this study proposed a multi-stage multidisciplinary design optimization (MS-MDO) method. First, the comprehensive artillery internal ballistic dynamics (AIBD) model, based on propellant combustion, rotation band engraving, projectile axial motion, and rifling wear models, was established and validated. This model was systematically decomposed into subsystems from a system engineering perspective. The study then detailed the MS-MDO methodology, which included Stage I (MDO stage) employing an improved collaborative optimization method for consistent design variables, and Stage II (Performance Optimization) focusing on the independent optimization of local design variables and… More >

Bo Liu^1,2, Li Feng^1,*, Yufeng Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 845-862, 2024, DOI:10.32604/cmes.2024.047695

Abstract This paper focuses on the effective utilization of data augmentation techniques for 3D lidar point clouds to enhance the performance of neural network models. These point clouds, which represent spatial information through a collection of 3D coordinates, have found wide-ranging applications. Data augmentation has emerged as a potent solution to the challenges posed by limited labeled data and the need to enhance model generalization capabilities. Much of the existing research is devoted to crafting novel data augmentation methods specifically for 3D lidar point clouds. However, there has been a lack of focus on making the most of the numerous existing… More >

Hayder Kareem Sakran^1,2, Mohd Sharizal Abdul Aziz^1,*, Chu Yee Khor³

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 109-137, 2024, DOI:10.32604/cmes.2024.047245

Abstract The centrifugal pump is a prevalent power equipment widely used in different engineering patterns, and the impeller blade wrap angle significantly impacts its performance. A numerical investigation was conducted to analyze the influence of the blade wrap angle on flow characteristics and energy distribution of a centrifugal pump evaluated as a low specific speed with a value of 69. This study investigates six impeller models that possess varying blade wrap angles (95°, 105°, 115°, 125°, 135°, and 145°) that were created while maintaining the same volute and other geometrical characteristics. The investigation of energy loss was conducted to evaluate the… More > Graphic Abstract

ÇAĞLA GÜL GÜLDİKEN, LEVENT AKYALÇIN, HASAN FERDİ GERÇEL^*

Journal of Polymer Materials, Vol.36, No.4, pp. 337-349, 2019, DOI:10.32381/JPM.2019.36.04.4

Abstract In the present study, polybenzimidazole (PBI) polymer which has a great importance in polymer electrolyte membrane (PEM) research was synthesized via the solution polycondensation method, under various synthesis conditions to put forward the effect of the synthesis parameters on the properties of the synthesized polymer and consequently to the quality of the prepared polymer electrolyte membrane. The synthesized polymers were characterized in terms of their chemical structure, thermal degradation behaviour, and molecular weight by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹ H NMR), thermogravimetric analysis (TGA). The Mechanical properties, acid-doping level capacity, proton conductivity, and fuel cell… More >

RAVI KUMAR, VISHWA PRATAP SINGH, MADHUKAR PRAJAPATI, ASHWITH, PRIYANKA SINGH, SATYAJIT SAMANTA, SAIKAT BANERJEE^*

Journal of Polymer Materials, Vol.36, No.4, pp. 323-335, 2019, DOI:10.32381/JPM.2019.36.04.3

Abstract Types of nucleating agents and their dosage level play an important role on the crystallinity of the polymer which controls the final properties like optical clarity, stiffness and reduced cycle time during molding. In this study, the efficiency of two different types of commercially available nucleating agents, phosphate ester and dicarboxylic acid based, have been studied. Both the nucleating agents were compounded with molding grade polypropylene homopolymer having melt flow index (MFI) of 12 g/10min at 2.16 Kg and 230°C, in a co-rotating twin screw extruder at two different dosage level, i.e. 300 ppm and 600 ppm. The effectiveness of… More >

A.K. GHOSH¹, RUTUJA S. BHOJE², R.C. BINDAL¹

Journal of Polymer Materials, Vol.37, No.1-2, pp. 109-120, 2020, DOI:10.32381/JPM.2020.37.1-2.8

Abstract In this study, cellulose triacetate (CTA) based nanocomposite membranes were developed by incorporation of carboxylic acid functionalized multiwalled carbon-nanotube (cMWCNT) and graphene oxide (GO) which have enhancement of both flux and fouling resistance properties of the membranes. Membranes were casted at room temperature and annealed at 90o C hot water for 10 minutes. The incorporation level of both the nanomaterials is 1.5% of the CTA polymer weight in the nanocomposite membranes. Prepared membranes were characterized in terms of water contact angle, surface morphology and mechanical strength. The performance of the membranes was evaluated both in reverse osmosis (RO) and forward… More >

ZHAO JUN^a, LIU AIQIN^a, ZHOU HONG^a, LUO JUN^b,*, AND LIU YUAN^b,*

Journal of Polymer Materials, Vol.37, No.1-2, pp. 29-42, 2020, DOI:10.32381/JPM.2020.37.1-2.3

Abstract Heteroatoms (N, O, and F) and hydrogen groups are important elements for forming the H-bonds. It is well known that a large number of hydrogen groups are formed after curing reaction of epoxy. However, literatures about epoxy resins containing heteroaromatic ring and the H-bonds after cure reaction of the epoxy resins are seldom published. To bridge the gap, a kind of new epoxy monomer containing pyridine ring (EMP) has been synthesized in this work, andit is further cured by 4,4-diaminodiphenyl methane (DDM). The properties of cured EMP/ DDM are evaluated by DSC, DMA, and static contact angle measurement. Moreover, the… More >

R.M. MISHRAA, R. VIJAYVARGIYAA, K.N. PANDEYA, J.S.P. RAIB

Journal of Polymer Materials, Vol.37, No.3-4, pp. 179-188, 2020, DOI:10.32381/JPM.2020.37.3-4.5

Abstract The present investigation is targeted to prepare nanocomposites based on binary blends of polyetherimide (PEI)-silicone rubber incorporated with varied loadings of nanotitanium dioxide particles. Nanocomposites have been prepared by melt blending process using twin screw extruder. Thermal properties of the developed nanocomposites have been investigated with the help of thermogravimetric analyzer (TGA) and dynamic mechanical analyzer (DMA). Scanning electron microscopy (SEM) is used to analyze the morphological properties of the nanocomposites. Mechanical properties (tensile strength, tensile modulus, elongation at break, impact strength) of the nanocomposites have been evaluated by universal testing machine (UTM). Mechanical testing results reveal that there is… More >

JITENDRA. S. TATE^1,2,*, HARISH KALLAGUNTA^1,2, ANDREW ALVAREZ¹

Journal of Polymer Materials, Vol.38, No.1-2, pp. 101-120, 2021, DOI:10.32381/JPM.2021.38.1-2.9

Abstract The exponential growth in composites and their increased use in military, aerospace, energy, and automotive industry is driven by their high performance and light weight. High performance thermosetting polymers such as cyanate ester have received considerable attention due to its ability of volatile-free curing. It also offers advantages such as excellent radiation shielding, high thermal stability, and hydrophobicity with lots of potential for enhanced mechanical strength. This research article discusses the results of effects of multiwalled carbon nanotubes (MWCNT) at predetermined loading levels of 0.5wt%, 1wt% and 1.5wt% on mechanical, thermal and flammability properties of cyanate ester modified carbon fiber… More >

DIPESHKUMAR D. KACHHADIYA, Z.V.P. MURTHY^*

Journal of Polymer Materials, Vol.38, No.1-2, pp. 49-61, 2021, DOI:10.32381/JPM.2021.38.1-2.5

Abstract The conventional process for methanol-water separation like distillation consumes about 60 % of total energy. As an alternative, researchers have developed a membrane-based separation process for alcohol-water mixtures separation. However, there is a big challenge for researches to separate alcohol-water aqueous mixtures using a polymeric membrane because of swelling. In the present work, the aim is to separate methanol from water by pervaporation using polymeric membranes made up of polyvinylidenefluroide (PVDF) and polyethylene glycol (PEG200) modified PVDF membranes. The membranes were characterized by thermogravimetry analysis (TGA), field emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FTIR). A study on… More >