Search Results

You are looking at 1 - 10 of 12 items for

  • Author: S. Suresh x
Clear All Modify Search
Open access

S. Chand

This paper deals with the theoretical investigation of the triple-diffusive convection in a micropolar ferrofluid layer heated and soluted below subjected to a transverse uniform magnetic field in the presence of uniform vertical rotation. For a flat fluid layer contained between two free boundaries, an exact solution is obtained. A linear stability analysis theory and normal mode analysis method have been employed to study the onset convection. The influence of various parameters like rotation, solute gradients, and micropolar parameters (i.e., the coupling parameter, spin diffusion parameter and micropolar heat conduction parameter) on the onset of stationary convection has been analyzed. The critical magnetic thermal Rayleigh number for the onset of instability is also determined numerically for sufficiently large value of the buoyancy magnetization parameter M1 (ratio of the magnetic to gravitational forces). The principle of exchange of stabilities is found to hold true for the micropolar fluid heated from below in the absence of micropolar viscous effect, microinertia, solute gradient and rotation. The oscillatory modes are introduced due to the presence of the micropolar viscous effect, microinertia , solute gradient and rotation, which were non-existent in their absence. In this paper, an attempt is also made to obtain the sufficient conditions for the non-existence of overstability.

Open access

S. Reena Devi, S. Suresh, S. Kalaiyarasi, M. Nizammohideen and R. Mohan Kumar

Abstract

A novel 4-methylpyridinium 3-nitrophthalate (4MP3NP) was synthesized and the crystals were grown by using slow evaporation method. The structural data of the grown crystal was collected by single crystal X-ray diffraction. It revealed that the 4MP3NP crystal belongs to triclinic crystal system with a space group P1. Structure of the synthesized compound was established using SHELXL 97 program package. The crystalline nature and composition of the grown crystal was established using high resolution X-ray diffraction and FT-IR analyses. UV-Vis transmittance and photoluminescence studies revealed the optical transmission window and electronic transition mechanism of ions, respectively. The laser damage threshold of the grown crystal was estimated by Nd:YAG laser and these results were mutually related to specific heat capacity of the grown crystal. The third-order nonlinear optical susceptibility of the grown crystal was studied by Z-scan technique.

Open access

S. Puttakame Gopalakrishna, M. Leckson Kaonga, R. Kalegowda Somashekar, H.Satyanarayana Suresh and R. Suresh

Abstract

Tree species inventories, particularly of poorly known dry deciduous forests, are needed to protect and restore forests in degraded landscapes. A study of forest stand structure, and species diversity and density of trees with girth at breast height (GBH) ≥10 cm was conducted in four management zones of Bannerghatta National Park (BNP) in the Eastern Ghats of Southern India. We identified 128 tree species belonging to 45 families in 7.9 hectares. However, 44 species were represented by ≤ 2 individuals. Mean diversity values per site for the dry forest of BNP were: tree composition (23.8 ±7.6), plant density (100.69 ± 40.02), species diversity (2.56 ± 0.44) and species richness (10.48 ± 4.05). Tree diversity was not significantly different (P>0.05) across the four management zones in the park. However, the number of tree species identified significantly (P<0.05) increased with increasing number of sampling sites, but majority of the species were captured. Similarly, there were significant variations (p<0.05) between tree diameter class distributions. Juveniles accounted for 87% of the tree population. The structure of the forest was not homogeneous, with sections ranging from poorly structured to highly stratified configurations. The study suggests that there was moderate tree diversity in the tropical dry thorn forest of Bannerghatta National Park, but the forest was relatively young.

Open access

C. S. Anita and R. M. Suresh

Abstract

Delivering Quality of Services (QoS) for cooperative Wireless Mesh Networks (WMN) is an important issue when enabling heterogeneous wireless technologies on the client side. A standard approach for satisfying the QoS requirements of different wireless clients appears to be a complex task due to the capacity variations. In addition to the routing layer, the information at the lower layers, such as Physical and Medium Access Control (MAC) layers must be considered for providing the QoS guarantee. The strength of a signal received from heterogeneous clients at the physical layer and the coupled network capacity at the MAC layer plays an important role in the efficient path assignment and time scheduling management for routing. Therefore, this paper proposes an Adaptive Multipath-Dynamic Source Routing (AM-DSR) protocol. It supports Cross-Layer Interaction (CLI) for path assignment and MAC scheduling mechanism for slot assignment to improve the mesh backbone performance for providing multimedia services to various wireless clients in a hybrid WMN. The proposed strategy measures the cross-layer parameter, such as the network capacity, using the Signal to Noise Ratio (SINR) and assigns a route that maximizes the efficiency of the multimedia services. Finally, the performance evaluation shows that the proposed cross-layer based AM-DSR protocol provides efficient QoS support for the mesh backbone enabling connections to multiple clients.

Open access

J. Suresh, S. Karthik and A. Arun

Abstract

The acrylate monomer was synthesized by two step process. 2,4-dichloro-1-ene(4-hydroxyphenyl)phenone (DHP) was synthesized using 4-hydroxy benzaldehyde and 2,4-dichloro acetophenone. 4-[3-(2,4-dichloro-phenyl)3-oxoprop-1-en-1-yl]phenylacrylate (DCP) was prepared by reacting DHP with acryloyl chloride. The synthesized monomer was copolymerized with 2-hydroxyethyl acrylate and styrene using solution polymerization technique. Monomer and polymers were characterized by IR, NMR and UV techniques. The average molecular weight of the polymer was around 4000 g/mol. First and second decomposition temperature of the polymers was around 320 °C and 430 °C, respectively. The reactivity ratio of the polymers was calculated by Fineman-Ross, Kelen-Tudos and extended Kelen-Tudos methods. The synthesized monomer has been less reactive than the commercial monomer. The rate of photocrosslinking increased from 39 % to 99 % due to the using of copolymerization technique.

Open access

Ayyalasomayajula Neelima, Ajumeera Rajanna, Reddy G. Bhanuprakash, C.S. Chetty and Challa Suresh

Abstract

Lead (Pb) is a toxic pollutant known to cause several abnormalities related to the brain, including cognitive dysfunction, and it is ubiquitous in nature. β-amyloid peptides (AP) are crucially involved in Alzheimer’s disease (AD). It has been reported that there is a connection between lead and amyloid peptides in exerting similar kinds of altered functions in the brain and long-term exposure to lead leads ultimately to increased beta amyloid formation in the brain, lethal to human brain cells. There is still a lack of information on the mechanism by which Pb affects AP formation, exerting combined toxicity in AD patients. To fill the gap, we have systematically analyzed the toxicity individually and in combination of Pb and AP in human brain cells. We found that the combination of Pb and AP exerted a higher toxicity than individual exposures in human neuroblastoma cells. The lower inhibitory concentration values were determined by both time and concentration dependent manner on using MTT assay. The data resulted in the development of enhanced toxicity on exposure to Pb with both the combinations of AP(1-40) or (25-35) and with all combinations in human brain cells compared to individual exposures to Pb (1-40) or AP(25-35). The severe apoptotic effect and alteration in cell cycle by arresting at the S-phase evidenced the increased toxicity of combinational exposure to Pb and AP on human neuroblastoma cells. Furthermore, the quantitative determination of LDH and caspase-3 activity indicated the induction of severe toxicity. We conclude that both are synergistically associated with effects such as arresting the cell cycle and triggering apoptosis during the progression of Alzheimer’s disease.

Open access

M. Suresh Kumar, K. Rajesh, G.V. Vijayaraghavan and S. Krishnan

Abstract

Good quality diglycine perchlorate (DGPCL) single crystals were grown by slow evaporation solution growth method using the combination of glycine and perchloric acid in the ratio of 2:1. Single crystal X-ray diffraction and mechanical characterization of the grown single crystals of diglycine perchlorate were analyzed in this article. Lattice parameters, space group and crytal system were found from single crystal X-ray diffraction analysis. All the cell parameters and space group are in a good agreement with the reported values. Mechanical properties, such as Vicker’s microhardness number, work hardening index, standard hardness value, yield strength, fracture toughness, brittleness index and elastic stiffness constant values, were determined using Vicker’s microhardness tester.

Open access

S. Babitha Merlin, M. Abirami and R. Suresh Kumar

Abstract

Indiscriminate disposal of wastewater with suspended solids have led to higher amount of pollution to the natural water bodies. Turbidity removal becomes an essential part in the water treatment when surface water is used for drinking purpose, this can be achieved by means of coagulation process. Coagulation process is the dosing of a coagulant in water, resulting in the destabilization of negatively charged particles. Commercial coagulants which were widely used can synthesize by-products in turn may pollute the environment and deteriorate the ecosystem at a slow rate. So, now-a-days natural coagulants are used as a potential substitute because it’s biodegradable, ecofriendly and non-toxic. In this study, the turbid surface water samples were treated using powdered seeds of Rajma (natural coagulant) followed by variations in dosage, settling time and pH were also studied. From the results obtained, it was found that the Rajma seeds powder achieved 48.80% efficiency for 0.5 g/l of optimum dose at pH 6 for 20 min settling time respectively.

Open access

Nitin R. Dighore, Priyanka L. Anandgaonker, Suresh T. Gaikwad and Anjali S. Rajbhoj

Abstract

Crystalline MoO3 nanoparticles were obtained by electrochemical synthesis process using tetrapropylammonium bromide as a stabilizer and structure-directing agent in ACN:THF(4:1) solvent. Formation of MoO3 nanoparticles took place at a constant supply current of 14 mA/cm2. These synthesized MoO3 nanoparticles were characterized by UV-Vis spectroscopy, FT-IR spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM). So prepared MoO3 nanoparticles were used as a heterogeneous catalyst for the synthesis of 2,6-bis(benzylidene)cyclohexanone derivatives. This protocol offers several advantages, such as simple work-up procedure, recyclability of the catalyst, excellent product yield in a short reaction time and purification of products with a non-chromatographic method.

Open access

Y. Allwin Roy, K. Gobivel, K.S. Vijay Sekar and S. Suresh Kumar

Abstract

Carbon fiber reinforced polymeric (CFRP) composite materials are widely used in aerospace, automobile and biomedical industries due to their high strength to weight ratio, corrosion resistance and durability. High speed machining (HSM) of CFRP material is needed to study the impact of cutting parameters on cutting forces and chip microstructure which offer vital inputs to the machinability and deformation characteristics of the material. In this work, the orthogonal machining of CFRP was conducted by varying the cutting parameters such as cutting speed and feed rate at high cutting speed/feed rate ranges up to 346 m/min/ 0.446 mm/rev. The impact of the cutting parameters on cutting forces (principal cutting, feed and thrust forces) and chip microstructure were analyzed. A significant impact on thrust forces and chip segmentation pattern was seen at higher feed rates and low cutting speeds.