Simplified numerical method for nonlocal static and dynamic analysis of a graphene nanoplate

Rahi, Mohammad Javad,Firoozjaee, Ali Rahmani,Dehestani, Mehdi Techno-Press 2021 Advances in materials research Vol.10 No.1

In this paper, the dynamic analysis of single-layer rectangular armchair graphene nanoplates has been considered. The theory of nonlocal elasticity for small scale effects and the Kirchhoff's theory for plates have been used to obtain the dynamic equation of graphene nanoplates.Discrete Least Squares Meshless (DLSM) method has been used to examine the response of single-layer graphene nanoplates with various boundary conditions. The validation of the results has also been carried out using dynamic analysis of single-layer rectangular armchair graphene nanoplates under stationary loads. Results revealed that DLSM method is an efficient mean to solve the problems of structural mechanics in nano-dimensions. In addition, in nanostructures, the small scale effects have considerable impacts that should be considered as well. An increase in nonlocal coefficient increases the deflection. Higher nonlocal coefficient leads to higher deflection intensity and vibration amplitude.

Thermo-mechanical analysis of functionally graded wheel-mounted brake disk

Tohid Mahmoudi,Ali Parvizi,Esmaeil Poursaeidi,Abbas Rahi 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

Having higher speed for trains requires improvement in braking performances. The brake system is an important part of locomotivesafety system in which the mechanical energy is converted to the thermal energy and distributed through the disks and pads. As a result,the temperature at the disks surfaces increases sharply. This phenomenon is called the thermal shock that causes the negative effects onthe brake disk surface such as fast aging, early wear, thermal cracks and the brake fade. Using Functionally graded materials (FGMs)which are more resistant to the thermal shock is a new trend to deal with this issue. In this study, the effects of using FG materials in thewheel-mounted brake disk R920K for the ER24PC locomotive on its thermo-mechanical behavior are investigated. For this purpose, theuncoupled thermo-mechanical analysis is performed for the disk made of FG Al-A359/SiCp, aluminum and ductile cast iron materials. Comparing the results of brake disk made of ductile cast iron with those from experimental data, the accuracy of present FE model isverified. Concerning the stress analysis, it is shown that the safety factor for the disk made of FG material is higher than the other ones. Furthermore, the gradation index of FG material has the most important effect on the thermo-mechanical performance of FG disks.

Diversity Analysis of Diazotrophic Bacteria Associated with the Roots of Tea (Camellia sinensis (L.) O. Kuntze)

( Arvind Gulati ),( Swati Sood ),( Praveen Rahi ),( Rishu Thakur ),( Sunita Chauhan ),( Isha Chawla Nee Chadha ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.6

The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included α-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; γ-Proteobacteria genera Pseudomonas and Stenotrophomonas; and β-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.

Evaluation of Machining Performance for Electrochemical Surface Grinding of Aluminium Based Hybrid MMC

Avanish Kumar Dubey,Dhruv Kant Rahi 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.9

Development of newer materials necessitates suitable machining devices which can overcome the limitations of existing conventional or unconventional machining systems. Keeping this in view, a hybrid machining set-up of electrochemical machining with surface grinding has been developed to study the machining performance of difficult-to-cut hybrid metal matrix composite Al-SiC-Gr. Effect of applied voltage, electrolyte concentration, wheel speed and work table speed on machining performance have been analysed. Material removal rate and surface finish significantly improve with increase in applied voltage or electrolyte concentration. Increase in grinding wheel speed and work table speed adversely affects the performance. Scanning Electron Microscopy images have been analysed to study the morphology of machined specimen.

Breast Cancer Risk Based on the Gail Model and its Predictors in Iranian Women

Mirghafourvand, Mojgan,Mohammad-Alizadeh-Charandabi, Sakineh,Ahmadpour, Parivash,Rahi, Pari Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8

Background: This study was carried out to examine breast cancer risk and its fertility predictors in women aged ${\geq}35$. Materials and Methods: This cross-sectional study was conducted on 560 healthy women referred to health centers of Tabriz-Iran, 2013-2014. Five-year and lifetime risk of developing breast cancer were determined using the Gail model. General linear modeling was applied to determine breast cancer predictors. Results: The mean age of the subjects was 42.7 (SD: 7.7) years. Mean 5-year and lifetime risks of developing breast cancer were determined to be 0.6% (SD: 0.2%) and 8.9% (SD: 2.5%), respectively. Variables of family history of breast cancer, age, age at menarche, parity, age at first childbirth, breastfeeding history, frequency of breastfeeding, method of contraception, marital status and education were all found to be predictors of breast cancer risk. Conclusions: According to the results of this study, screening programs based on the Gail model should be implemented for Iranian people who have a high risk for breast cancer in order to facilitate early detection and better plan for possible malignancies.

Cold-Adapted and Rhizosphere-Competent Strain of Rahnella sp. with Broad-Spectrum Plant Growth-Promotion Potential

( Pratibha Vyas ),( Robin Joshi ),( K. C. Sharma ),( Praveen Rahi ),( Ashu Gulati ),( Arvind Gulati ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.12

A phosphate-solubilizing bacterial strain isolated from Hippophae rhamnoides rhizosphere was identified as Rahnellu sp. based on its phenotypic features and 165 rRNA gene sequence. The bacterial strain showed the growth characteristics of a cold-adapted psychrotroph, with the multiple plant growth-promoting traits of inorganic and organic phosphate solubilization, 1-aminocyclopropane-1-carboxylate-deaminase activity, ammonia generation, and siderophore production. The strain also produced indole-3-acetic acid, indole-3-acetaldehyde, indole-3-acetamide, indole-3-acetonitrile, indole-3-lactic acid, and indole-3-pyruvic acid in tryptophan-supplemented nutrient broth. Gluconic, citric and isocitric acids were the major organic acids detected during tricalcium phosphate solubilization. A rifampicin-resistant mutant of the strain exhibited high rhizosphere competence without disturbance to the resident microbial populations in pea rhizosphere. Seed bacterization with a charcoal-based inoculum significantly increased growth in barley, chickpea, pea, and maize under the controlled environment. Microplot testing of the inoculum at two different locations in pea also showed significant increase in growth and yield. The attributes of cold-tolerance, high rhizosphere competence, and broad-spectrum plant growth-promoting activity exhibited the potential of Rahnella sp. BIHB 783 for increasing agriculture productivity.

In-vivo antiproliferative activity of Morus latifolia leaf and bark extracts against Ehrlich’s ascites carcinoma

Md. Shihabul Islam,Chowdhury Arif Jahangir,Md. Sifat Rahi,Md. Mahmudul Hasan,Salek Ahmed Sajib,Kazi Md. Faisal Hoque,Md Abu Reza 한국독성학회 2020 Toxicological Research Vol.36 No.1

Cancer is the second death causing disease all over the world and until today 100 different types of cancer have been identified whose treatment methods consist of serious side effects on human body. To reduce the frequency of adverse effects of cancer treatment, nowadays plant derived natural components are getting priority. The plant Morus latifolia is widely available in northern part of Bangladesh. The earlier researches suggested that popular varieties of some Morus sp. like Morus alba, Morus indica etc. have good anti-proliferative activity. Hence, this study was designed to evaluate the anti-proliferative activity of leaf and bark extracts of M. latifolia against Ehrlich’s ascites carcinoma (EAC) in vivo. The leaf and bark extracts of M. latifolia were used in several bioassays including Brine shrimp lethality test, hemagglutination activity test, antioxidant activity test, and cell growth inhibition test. Besides, fluorescence microscopy was performed to study apoptotic features in EAC cells, and molecular analysis like real-time PCR were also conducted. The results of Brine shrimp lethality test, hemagglutination activity test, and antioxidant activity assay supported the cell growth inhibition capability of leaf and bark extracts which was confirmed by in vivo cell growth inhibition bioassay. Moreover, the experimental extracts were able to induce cell apoptotis through altering the expression pattern of Bcl-2 and Bax genes. All of the results of this study suggest that several noble compounds are present in M. latifolia plant extracts which are capable for healing cancer cells.