Heterogeneous modulation of exciton emission in triangular WS₂ monolayers by chemical treatment

Dhakal, Krishna P.,Roy, Shrawan,Yun, Seok Joon,Ghimire, Ganesh,Seo, Changwon,Kim, Jeongyong The Royal Society of Chemistry 2017 Journal of materials chemistry. C, Materials for o Vol.5 No.27

<▼1><P>Spatially heterogeneous effects of bis(trifluoromethane)sulfonimide (TFSI) and benzyl viologen (BV) treatment on the optical properties of triangular monolayer tungsten disulfides are investigated by nanoscale spectral imaging.</P></▼1><▼2><P>Chemical treatments were recently shown to be very effective in enhancing the exciton emission of monolayer transition metal dichalcogenides (1L-TMDs) by suppressing the exciton quenching caused by structural defects. However, the effects of these chemical treatments varied greatly depending on the synthesis method and the type of 1L-TMD; therefore, the exact origin of the emission enhancement is still elusive. Here we report the spatially heterogeneous effects of bis(trifluoromethane)sulfonimide (TFSI) and benzyl viologen (BV) treatment on the optical properties of triangular 1L-WS2 grown by chemical vapor deposition (CVD). Nanoscale photoluminescence (PL) and Raman spectral maps showed that TFSI had a minimal effect on the inner region of the triangular WS2 grain, whereas the PL of the edge region was enhanced up to 25 times; further, BV reduced the PL, also more strikingly in the edge region. Systematic variation of the spectral weights among neutral excitons, trions, and bi-excitons indicated that p-doping and n-doping with TFSI and BV, respectively, occurred in both the inner and edge regions; however, the PL enhancement was attributed mainly to the reduction of structural defects caused by TFSI treatment. Our observation of the spatially heterogeneous effects of chemical treatment suggests that the inner and edge regions of CVD-grown 1L-WS2 are populated with different types of structural defects and helps in clarifying the mechanism by which chemical treatment enhances the optical properties of 1L-TMDs.</P></▼2>

Michaelis-Menten Behaviour in the Oxidation of Benzaldehydes by Pyridinium Chlorochromate (Corey's Reagent)

Ganesh P. Panigrahi,Sasananda Padhy Korean Chemical Society 1992 Bulletin of the Korean Chemical Society Vol.13 No.5

The oxidation of benzaldehyde, 3,4-dimethoxy benzaldehyde, p-methoxy benzaldehyde, m-$NO_2$-benzaldehyde, and m-chlorobenzaldehyde by pyridinium chlorochromate (Corey's reagent) are reported. Michaelis-Menten behaviour is observed. The rate determining step appears to be the decomposition of a complex of benzaldehyde with PCC either through a loss of $H^+$ or $H^-$ ions.

Fracture energy and tension softening relation for nanomodified concrete

A. Ramachandra Murthy,P. Ganesh,S. Sundar Kumar,Nagesh R. Iyer 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.6

This paper presents the details of size independent fracture energy and bi-linear tension softening relation for nano modified high strength concrete. Nano silica in powder form has been used as partial replacement of cement by 2 wt%. Two popular methods, namely, simplified boundary effect method of Karihaloo et al. (2003) and RILEM (1985) fracture energy with P-δ tail correction have been employed for estimation of size independent fracture energy for nano modified high strength concrete (compressive strength ranges from 55 MPa to 72 MPa). It is found that both the methods gave nearly same values, which is an additional evidence that either of them can be employed for determination of size independent fracture energy. Bi-linear tension softening relation corresponding to their size independent fracture energy has been constructed in an inverse manner based on the concept of non-linear hinge from the load-crack mouth opening plots of notched three-point bend beams.

Fabrication of the flexible nanogenerator from BTO nanopowders on graphene coated PMMA substrates by sol-gel method

Sankar Ganesh, R.,Sharma, Sanjeev K.,Abinnas, N.,Durgadevi, E.,Raji, P.,Ponnusamy, S.,Muthamizhchelvan, C.,Hayakawa, Y.,Kim, Deuk Young Elsevier Sequoia S.A 2017 Materials chemistry and physics Vol.192 No.-

<P><B>Abstract</B></P> <P>Nanostructured bismuth titanate (Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB>) or BTO powders were synthesized by the combustion method. The crystalline phase of BTO nanopowders was evaluated from X-ray diffraction (XRD) and further confirmed by selected area electron diffraction (SAED) pattern. The SEM and TEM micrographic images clearly showed the nanosheets like morphology of BTO nanopowder. The EDS spectrum of BTO nanopowder showed the elemental peaks of O, Bi and Ti at 0.53 keV, 2.41 keV and 4.49 keV, respectively. FTIR band peaks were observed at 815 and 595 cm<SUP>−1</SUP> corresponding to the stretching vibrations of BiO and TiO. The red shift in optical absorption of BTO was observed and the bandgap decreased from 3.18 to 3.08 eV as the calcined temperature increased from 600 to 800 °C. The sandwich structure, called the nanogenerator, Graphene/BTO-PDMS/Graphene (G/BTO/G), was fabricated on graphene coated polymethyl methacrylate (PMMA) substrates, which produced a peak voltage (10 mV) by applying the pressure from human's finger. The switching mechanism of BTO nanosheets was observed to be dependent on the polarity and intrinsic dipole formation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> (BTO) nanosheets synthesized from a simple combustion method. </LI> <LI> SEM & TEM images confirmed the nanosheets structure with a hexagonal shape. </LI> <LI> XRD and SAED pattern of BTO nanosheets confirmed the orthorhombic crystal structure. </LI> <LI> Flexible G/BTO/G nanogenerator fabricated by sol-gel method. </LI> <LI> Peak voltage was observed to be 10 mV by applying pressure from human's finger. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Evidencing enhanced charge-transfer with superior photocatalytic degradation and photoelectrochemical water splitting in Mg modified few-layered SnS₂

Mohan Kumar, G.,Cho, H.D.,Ilanchezhiyan, P.,Siva, C.,Ganesh, V.,Yuldashev, Sh.,Madhan Kumar, A.,Kang, T.W. Elsevier 2019 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.540 No.-

<P><B>Abstract</B></P> <P>Recently there has been immense interest in the exploration of richly available two-dimensional non-toxic layered material such as tin disulfide (SnS<SUB>2</SUB>) for potential employment in energy and environmental needs. In this regard, we report on the synthesis of few-layered Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB> nanosheets through a facile one-step hydrothermal route to address all such functions concerning photocatalysis and photoelectrochemical conversion. The crystalline order and structure of processed layered Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB> were initially found to exhibit a strong influence on their physicochemical properties. Their optical properties attest the Mg doping in SnS<SUB>2</SUB> to benefit us with enhanced visible-light absorption via red-shift in their absorption edge. In the photoluminescence spectrum the emissions observed along visible and red region signifies the association of Mg related trap states in Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB>. Next, the photocurrent and electrochemical impedance spectroscopic results revealed the Mg doping to promote the effective charge transfer process (which was beneficial to enhance their photocatalytic activity). Consequently, the layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> made photoanodes displayed 1.7 fold higher photocurrent density under simulated solar radiation with respect to their undoped counterpart. Furthermore, the layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets exhibits enhanced visible light decomposition of organic dye while compared with pristine SnS<SUB>2</SUB> nanosheets. The value of rate constants obtained for the Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets was found to be 1.4 times higher than that of pristine SnS<SUB>2</SUB>. Finally, the results obtained through the present study projects the huge potential of layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets for future multifunctional applications.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Photocatalytic properties of Mn-doped NiO spherical nanoparticles synthesized from sol-gel method

Sankar, S.,Sharma, Sanjeev K.,An, Namhyun,Lee, Hwauk,Kim, Deuk Young,Im, Young Bin,Cho, Yung Duk,Ganesh, R. Sankar,Ponnusamy, S.,Raji, P.,Purohit, L.P. Elsevier 2016 OPTIK -STUTTGART- Vol.127 No.22

<P><B>Abstract</B></P> <P>Mn-doped NiO (NiO:Mn) nanopowders were synthesized from an inexpensive sol-gel method. The XRD peak profile analysis of NiO:Mn nanopowders confirmed the cubic structure. The spherical nanoparticles of NiO:Mn were evaluated from the SEM and TEM analysis and the grain size decreased as the Mn concentration increased. The average crystallite size decreased from 35.44nm to 30.5nm and the bandgap increased from 3.79eV to 3.95eV as the Mn concentration increased from 0wt.% to 4wt.%. The photocatalytic properties of NiO:Mn nanopowders were measured for the lowest and highest Mn dopant concentrations (Mn: 0 & 4wt.%) by using the methylene blue dye under UV illumination. The NiO:Mn (Mn: 4wt.%) nanoparticles showed the highest photocatalytic activity due to the highest activation sites. Therefore, it is revealed that the Mn: 4wt.% nanoparticles are observed to be more suitable for the photocatalytic activity of methylene blue dye degradation.</P>

Performance enhancement of a doublepass solar air heater with a shot-blasted absorber plate and winglets

P. Ganesh Kumar,D. Sakthivadivel,K. Balaji,Mohammed Salman,Sung Chul Kim 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

A double-pass solar air heater (DPSAH) with shot blasting and winglets in the air passage is a recommended cost-effective design development to enhance thermal performance. Three different absorber plate configurations for DPSAHs were experimentally tested: (a) V-corrugation with shot blasting, (b) V-corrugation with shot blasting and a 4-3 winglet pattern, and (c) V-corrugation with shot blasting with a 3-2 winglet pattern. Furthermore, aluminum winglets were welded to the DPSAH absorber plate to increase the channel turbulence to enhance the heat transfer performance. The pressure drop and thermal performance of the DPSAHs with and without winglets were investigated using meteorological parameters such as ambient temperature, wind speed, solar irradiance, and interior temperature at regular time intervals. V-corrugation with 4-3 winglets has a maximum thermal efficiency and pressure drop of 49.5 % and 230 Pa, respectively, at a mass flow rate of 0.02 m/s. Results showed that the thermal efficiency of V-corrugation with 4-3 winglets was improved by a maximum of 7 % compared with the V-corrugation air heater. Finally, increasing the mass flow rate from 0.01 kg/s to 0.02 kg/s increases the pressure drop by 1.22 times for the V-corrugation and 1.3 times for the V-corrugation with 4-3 winglets. Furthermore, a complete economic study of DPSAHs for India is examined in this article.

Repair, retrofitting and rehabilitation techniques for strengthening of reinforced concrete beams - A review

Ganesh, P.,Murthy, A. Ramachandra Techno-Press 2019 Advances in concrete construction Vol.8 No.2

Structural strengthening of reinforced concrete (RC) beams is becoming essential to meet the up-gradation of existing structures due to the infrastructure development. Strengthening is also essential for damaged structural element due to the adverse environmental condition and other distressing factors. This article reviews the state of the field on repair, retrofitting and rehabilitation techniques for the strengthening of RC beams. Strengthening of RC beams using various promising techniques such as externally bonded steel plates, concrete jacketing, fibre reinforced laminates or sheets, external prestressing/external bar reinforcement technique and ultra-high performance concrete overlay have been extensively investigated for the past four decades. The primary objective of this article is to discuss investigations on various strengthening techniques over the years. Various parameters that have been discussed include the flexural capacity, shear strength, failure modes of various strengthening techniques and advances in techniques over the years. Firstly, background information on strengthening, including repair, retrofitting, and rehabilitation of RC beams is provided. Secondly, the existing strengthening techniques for reinforced concrete beams are discussed. Finally, the relative comparisons and limitations in the existing techniques are presented.

Additively Manufactured Lattice Structures and Materials: Present Progress and Future Scope

Ganesh P. Borikar,Ashutosh R. Patil,Snehal B. Kolekar 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.11

Lattice patterns are designed to create lighter and stronger structures for various industrial applications. With progress in additive technology, lattice structure investigations have become feasible and realistic for efficient product and structural developments. The present study provides an overview of additively manufactured lattice structures along with their cell types, properties, model analysis, printing, and testing mechanical behaviour with adapted materials. The study focus on the behaviour of polymer lattice structures, including thermoplastics and resins, studying energy absorption, weight minimization, improvement of mechanical properties, and failure modes. Systematic literature research has been carried out (from 2006 to 2023) to highlight research gaps and challenges associated with lattice structures, simulation modelling, 3D prints, and structural tests. The study portrays insufficient investigations on fused deposition modelling and stereolithography-based lattice structures with polymers, composites, and metals, limited lattice structures comparative output data, design not withstanding specific energy absorption, low mechanical properties of materials and lattice, lag on the ceramic resins study. The authors report that by applying topology optimisation, comparison, and combination of lattice structures, the use of functionally graded materials, multi-material structures, controlled porosity and flexibility, they can resolve these challenges. The authors are hopeful that this research will be useful for next generation researchers and practitioners in miniaturisation and green product development.

User Perception on E-resources at University Libraries in India: A Case Study of SRM University

P. Rajendran,P. Ganesh 한국도서관·정보학회 2015 한국도서관정보학회지 Vol.46 No.4

The researcher conducts the survey through questioner method and analyzed the data in detail about E-resources available at SRM University library. The objectives of the study are to find out the awareness of use and purposes and their level of satisfaction of users. Further the researcher identifies the barrier and the ways and means of improvement of the use of E-resources. A total of 1,205 respondent was participating in this survey.