Surface energy and wettability of van der Waals structures

Annamalai, M.,Gopinadhan, K.,Han, S.,Saha, S.,Park, H.,Cho, E.,Kumar, B.,Patra, A.,Kim, S. W.,Venkatesan, T. Royal Society of Chemistry 2016 Nanoscale Vol.8 No.10

<P>The wetting behaviour of surfaces is believed to be affected by van der Waals (vdW) forces; however, there is no clear demonstration of this. With the isolation of two-dimensional vdW layered materials it is possible to test this hypothesis. In this paper, we report the wetting behaviour of vdW heterostructures which include chemical vapor deposition (CVD) grown graphene, molybdenum disulfide (MoS2) and tungsten disulfide (WS2) on few layers of hexagon boron nitride (h-BN) and SiO2/Si. Our study clearly shows that while this class of two-dimensional materials are not completely wetting transparent, there seems to be a significant amount of influence on their wetting properties by the underlying substrate due to dominant vdW forces. Contact angle measurements indicate that graphene and graphene-like layered transitional metal dichalcogenides invariably have intrinsically dispersive surfaces with a dominating London-vdW force-mediated wettability.</P>

Gut Bacterial Diversity of Insecticide-Susceptible and -Resistant Nymphs of the Brown Planthopper Nilaparvata lugens Stal (Hemiptera: Delphacidae) and Elucidation of Their Putative Functional Roles

( Vijayakumar M. Malathi ),( Ravi P. More ),( Rangasamy Anandham ),( Gandhi R. Gracy ),( Muthugounder Mohan ),( Thiruvengadam Venkatesan ),( Sandipan Samaddar ),( Sushil K. Jalali ),( Tongmin Sa ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.6

Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-tophenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.

Seismic behavior of steel and sisal fiber reinforced beam-column joint under cyclic loading

S.M. Kavitha,G. Venkatesan,Siva Avudaiappan,Chunwei Zhang 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.5

The past earthquakes revealed the importance of the design of moment-resisting reinforced concrete framed structures with ductile behavior. Due to seismic activity, failures in framed structures are widespread in beam-column joints. Hence, the joints must be designed to possess sufficient strength and stiffness. This paper investigates the effects of fibers on the ductility of hybrid fiber reinforced self-compacting concrete (HFRSCC) when subjected to seismic actions; overcoming bottlenecks at the beam-column joints has been studied by adding low modulus sisal fiber and high modulus steel fiber. For this, the optimized dose of hooked end steel fiber content (1.5%) was kept constant, and the sisal fiber content was varied at the rate of 0.1%, up to 0.3%. The seismic performance parameters, such as load-displacement behavior, ductility, energy absorption capacity, stiffness degradation, and energy dissipation capacity, were studied. The ductility factor and the cumulative energy dissipation capacity of the hybrid fiber (steel fiber, 1.5% and sisal fiber, 0.2%) added beam-column joint specimen is 100% and 121% greater than the control specimen, respectively. And also the stiffness of the hybrid fiber reinforced specimen is 100% higher than the control specimen. Thus, the test results showed that adding hybrid fibers instead of mono fibers could significantly enhance the seismic performance parameters. Therefore, the hybrid fiber reinforced concrete with 1.5% steel and 0.2% sisal fiber can be effectively used to design structures in seismic-prone areas.

A Comparative Study Between Linear Regression and Support Vector Regression Model Based on Environmental Factors of a Smart Bee Farm

A.B.M. Salman Rahman,이명배,신창선,Saravanakumar Venkatesan,임종현 (사)한국스마트미디어학회 2022 스마트미디어저널 Vol.11 No.5

Honey is one of the most significant ingredients in conventional food production in different regions of the world. Honey is commonly used as an ingredient in ethnic food. Beekeeping is performed in various locations as part of the local food culture and an occupation related to pollinator production. It is important to conduct beekeeping so that it generates food culture and helps regulate the regional environment in an integrated manner in preserving and improving local food culture. This study analyzes different types of environmental factors of a smart bee farm. The major goal of this study is to determine the best prediction model between the linear regression model (LM) and the support vector regression model (SVR) based on the environmental factors of a smart bee farm. The performance of prediction models is measured by R2 value, root mean squared error (RMSE), and mean absolute error (MAE). From all analysis reports, the best prediction model is the support vector regression model (SVR) with a low coefficient of variation, and the R2 values for Farm inside temperature, bee box inside temperature, and Farm inside humidity are 0.97, 0.96, and 0.44.

Scalability Improvement and Analysis of Permissioned-Blockchain

Swathi P.,M. Venkatesan 한국통신학회 2021 ICT Express Vol.7 No.3

Through the Bitcoin application, the innovative technology was miraculously launched in the markets, influencing numerous industries. Bitcoin is nothing but a form of digital currency (cryptocurrency) that can be used for trading in place of fiat money, where the underlying infrastructure is called Blockchain. The Blockchain is an open ledger that provides decentralization, transparency, immutability, and confidentiality. Blockchain can be used in massive, beneficial applications such as healthcare, logistics, supply chain management, the Internet of Things (IoT), etc. Most of the industrial applications rely on the permissioned Blockchain. However, the permissioned Blockchain fails in some aspects, such as scalability and throughput. This paper suggests a system to solve the scalability issue of permissioned Blockchain by incorporating data science techniques. The scalability analysis of the proposed solution is done in the hyperledger fabric framework with a variable number of transactions and results in scalability improvement.

Surface Plasmon Enhanced Photoluminescence of Rhodamine B Confined in SBA15

K. Dinakaran,A. Chandramohan,M. R. Venkatesan,S. Devaraj,V. Devi,M. Alagar 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.11

Rhodamine B dye (RB) has been introduced into the mesoporous silica (SBA15) and Ag anchored mesoporous silica by applying solution impregnation method. Surface treatment of SBA15 with 3-aminopropyltrimethoxysilane (APTMS) facilitates selective anchoring of the RB molecules on SBA15. The photoluminescence spectra of RB confined within SBA15 indicates higher emission intensity, than that of the RB solid, particularly in the presence of Ag nanoparticles. The significant enhancement in photoluminescence intensity is attributed to the local enhancement of the optical fields near the molecules by interactions with silver plasmons.

Surface Plasmon Enhanced Photoluminescence of Rhodamine B Confined in SBA15

Dinakaran, K.,Chandramohan, A.,Venkatesan, M.R.,Devaraj, S.,Devi, V.,Alagar, M. Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.11

Rhodamine B dye (RB) has been introduced into the mesoporous silica (SBA15) and Ag anchored mesoporous silica by applying solution impregnation method. Surface treatment of SBA15 with 3-aminopropyltrimethoxysilane (APTMS) facilitates selective anchoring of the RB molecules on SBA15. The photoluminescence spectra of RB confined within SBA15 indicates higher emission intensity, than that of the RB solid, particularly in the presence of Ag nanoparticles. The significant enhancement in photoluminescence intensity is attributed to the local enhancement of the optical fields near the molecules by interactions with silver plasmons.

반쪽 금속 호이슬러 화합물 Mn₃Ga의 연 X선 방사광 분광 연구

성승호(Seungho Seong),이은숙(Eunsook Lee),김현우(Hyun Woo Kim),김대현(D. H. Kim),강정수(J.-S. Kang),M. Venkatesan,J. M. D. Coey 한국자기학회 2016 韓國磁氣學會誌 Vol.26 No.6

By employing photoemission spectroscopy (PES) and soft X-ray absorption spectroscopy (XAS), the electronic structure of the candidate half-metallic antiferromagnet of Mn₃Ga Heusler compound has been investigated. We have studied two ball-milled Mn₃Ga powder samples, one after annealing and the other without annealing, respectively. Based on the Mn 2p XAS study, we have found that Mn ions are nearly divalent in Mn₃Ga and that the Mn ions having the locally octahedral symmetry and those having the locally tetrahedral symmetry are both present in Mn₃Ga. We have found relatively good agreement between the measured valence-band PES spectrum of Mn₃Ga and the calculated density of states, which is in agreement with the half-metallic electronic structure of Mn₃Ga.