Evaluation of Growth and Wood Traits in E. camaldulensis and Interspecific Eucalypt Hybrid Clones Raised at Three Diverse Sites in Southern India

Rathinam Kamalakannan,Suraj Poreyana Ganapathy,Shri Ram Shukla,Mohan Varghese,Chandramana Easwaran Namboothiri Jayasree 강원대학교 산림과학연구소 2023 Journal of Forest Science Vol.39 No.1

Twenty-five Eucalyptus clones (14 E. camaldulensis - EC and 11 interspecific eucalypt hybrid clones - EH) grown in three contrasting sites were evaluated for the growth and few wood traits at 4 years of age. The stability, genotype-site interaction and suitability of these clones for pulp and solid wood industry sectors were studied. Growth of eucalypt clones was significantly higher at site 1 with higher rainfall, but wood density did not differ significantly from lower rainfall sites. Kraft pulp yield (KPY) decreased from sites 1 to 3 based on moisture availability, but not between two groups of clones. Volumetric shrinkage (VS) was significantly higher in EC clones at site 3 with lowest rainfall, but there was no specific trend at other two sites with maximum (site 1) and intermediate (site 2) rainfall. The mechanical traits modulus of rupture (MOR) and modulus of elasticity (MOE) were at par in sites 1 and 2, but significantly lower at the driest site 3. The growth rate had a significant positive correlation with KPY, MOR and MOE and a negative correlation with VS, but no significant impact on wood density in both groups of clones. Genotype×environment interaction (G×E) was evident in most traits due to the difference in response of clones to moisture availability. Since wood density was negatively correlated to KPY, it has to be kept at an optimum level for the profitability of pulp industry. There was no significant difference between EC and EH clones for most traits except VS at site 3. Stability of clones varied across sites in different traits, and hence clones may be selected for deployment at each site by screening for growth, followed by wood density, considering the relationship of growth and density with other traits required by pulp and solid wood industry sectors.

Evaluation of protective coatings for geopolymer mortar under aggressive environment

Rathinam, Kumutha,Kanagarajan, Vijai,Banu, Sara Techno-Press 2020 Advances in materials research Vol.9 No.3

The aim of this study is to investigate the durability of fly ash based geopolymer mortar with and without protective coatings in aggressive chemical environments. The source materials for geopolymer are Fly ash and Ground Granulated Blast furnace Slag (GGBS) and they are considered in the combination of 80% & 20% respectively. Two Molarities of NaOH solution were considered such as 8M and 10M. The ratio of binder to sand and Sodium silicate to Sodium hydroxide solution (Na₂SiO₃/NaOH) are taken as 1:2 and 2 respectively. The alkaline liquid to binder ratio is 0.4. Compressive strength tests were conducted at various ages of the mortar specimens. In order to evaluate the performance of coatings on geopolymer mortar under aggressive chemical environment, the mortar specimens were coated with two different types of coatings such as epoxy and Acrylic. They were then subjected to different chemical environments by immersing them in 10% standard solutions of each ammonium nitrate, sodium chloride and sulphuric acid. Drop in compressive strength as a result of chemical exposure was considered as a measure of chemical attack and the drop in compressive strength was measured after 30 and 60 days of chemical exposure. The compressive strength results following chemical exposure indicated that the specimens containing the acrylic coating proved to be more resistant to chemical attacks. The control specimen without coating showed a much greater degree of deterioration. Therefore, the application of acrylic coating was invariably much more effective in improving the compressive strength as well as the resistance of mortar against chemical attacks. The results also indicated that among all the aggressive attacks, the sulphate environment has the most adverse effect in terms of lowering the strength.

Integration of Standalone Solar Power System with Flying Capacitor Multilevel Inverter Contingent on Synchronous Sequential Circuit

Rathinam Angamuthu,Balaji Govindan 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.11

The proposed system deals with the conversion of solar power into fundamental AC power by using flying capacitor multilevel inverter controlled by synchronous sequential circuits. The flying capacitor multilevel inverter controls the real and reactive power flow, deep voltage sags and short duration outages. The performance of the inverter is enhanced by using a synchronous sequential circuit, which gives the superior performance by reducing the total harmonic distortion in load voltage and capacitor voltage fluctuations. The synchronous sequential circuit based multilevel inverter offers several advantages like simpler structure, easy fault identification, cost-effectiveness and low power consumption. The performance of proposed strategy has been confirmed through simulation and hardware investigations.

Reduction of Components in New Family of Diode Clamp Multilevel Inverter Ordeal to Induction Motor

Rathinam Angamuthu,Karthikeyan Thangavelu,Ramani Kannan 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.1

This paper describes the design and implementation of a new diode clamped multilevel inverter for variable frequency drive. The diode clamp multilevel inverter has been widely used for low power, high voltage applications due to its superior performance. However, it has some limitations such as increased number of switching devices and complex PWM control. In this paper, a new topology is proposed. New topology requires only (N-1) switching devices and (N-3) clamping diodes compared to existing topology. A modified APO-PWM control method is used to generate gate pulses for inverter. The proposed inverter topology is coupled with single phase induction motor and its performance is tested by MATLAB simulation. Finally, a prototype model has built and its performance is tested with single phase variable frequency drive.

Static Buckling Analysis of Thin Cylindrical Shell with Centrally Located Dent under Uniform Lateral Pressure

N. Rathinam,B. Prabu 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.3

One of the common failure modes of thin cylindrical shell subjected to external pressure is buckling. The buckling pressure of these shell structures are dominantly affected by the geometrical imperfections present in the cylindrical shell which are very difficult to alleviate during manufacturing process. Dent is one of the common geometrical imperfections present in thin shell structures which may be formed due to mechanical damage caused by accidental loading or impact. In this work, influence of various dent parameters (dent length, dent width, dent depth and angle of orientation of the dent) on the critical buckling pressure of thin cylindrical shells with a centrally located dent is studied using non-linear static finite-element analysis of ANSYS under external pressure with simply supported boundary conditions at the top and bottom edges of the thin cylindrical shell.

Variable thermal loading analysis on (111) plane of single crystal gold

Murugavel Rathinam 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.11

The temperature response on the properties of single crystal gold (111) plane at elevated temperatures was considered in this work. The ability to perform nanoindentation experiments at elevated temperatures opens up significant new possibilities in nanotechnology. The experiments are performed at various temperatures of 373 K, 473 K and 573 K with tailor made Berkovitch tip of radius 100 nm to study the behavior of single crystal gold. The new phenomenon of material bouncing back under the indenter at the end of unloading was clearly noted, due to the accumulation of high energy. The results for different temperatures were compared. Our experiments clearly show the onset of the first burst of dislocation glide, which is indicated by a sudden increase of displacement with no increase of loading,the onset of plastic deformation in connection with the periodic bursts, and the strain hardening, softening and release effects. Pile up was also observed. The complete elastic range was found. There was significant drop in the hardness, elastic modulus and the increase in depth with increasing temperature. The elastic recovery was reduced at higher temperatures.

Reduction of Components in New Family of Diode Clamp Multilevel Inverter Ordeal to Induction Motor

Angamuthu, Rathinam,Thangavelu, Karthikeyan,Kannan, Ramani The Institute of Electronics and Information Engin 2016 Journal of semiconductor technology and science Vol.16 No.1

This paper describes the design and implementation of a new diode clamped multilevel inverter for variable frequency drive. The diode clamp multilevel inverter has been widely used for low power, high voltage applications due to its superior performance. However, it has some limitations such as increased number of switching devices and complex PWM control. In this paper, a new topology is proposed. New topology requires only (N-1) switching devices and (N-3) clamping diodes compared to existing topology. A modified APO-PWM control method is used to generate gate pulses for inverter. The proposed inverter topology is coupled with single phase induction motor and its performance is tested by MATLAB simulation. Finally, a prototype model has built and its performance is tested with single phase variable frequency drive.

Nanoindentation of aluminum (100) at various temperatures

Murugavel Rathinam,Ramesh Thillaigovindan,Prema Paramasivam 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.10

High temperatures generally affect materials in some form. In this regard, the capability to perform nanoscale measurements at elevated temperatures opens up new possibilities for investigating the temperature dependence of materials’ mechanical properties. Particularly, the responses of aluminum’s different mechanical properties to indentation at various temperatures have been studied experimentally. In this paper, aluminum response to different room temperatures was examined. The behaviors of a single crystal aluminum during loading and unloading were observed. Nanoindentation experiments on a single crystal aluminum (100) sample at temperatures of 265 K and 388 K were performed with different loading conditions. At the start of the first burst of the dislocation glide, which was indicated by a sudden increase in displacement with no increase in loading, evidence of plastic properties and softening effects on aluminum was identified. The ductile to brittle transition was observed at temperatures below 273 K. Generally, there was a significant increase in the penetration depth and a decrease in hardness, elastic modulus, and elastic recovery as the testing temperature increased.

Molecular interactions of graphene with HIV-Vpr, Nef and Gag proteins: A new approach for treating HIV infections

Navanietha Krishnaraj Rathinam,Chandran Saravanan,Pal Parimal,Varalakshmi Perumal,Malliga Perumal 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.5

Graphene draws considerable attention among biomedical researchers because of its unique physical, chemicaland biological properties. The wide applications of graphene in the biomedical arena such as diagnostics, drug immobilizationand drug delivery were well documented in the literature. However the therapeutic potential of the graphenetowards retroviruses and the interactions of the graphene with receptors/proteins are still unexplored. Herein we reportthe antagonistic molecular interactions of graphene with the three key target proteins of HIV infections namely HIVVpr,Nef and Gag proteins. The docking investigations were performed to find the binding energy of the graphene ligandsto the key target proteins of HIV. The high binding affinity of the graphene to these proteins indicates the antagonisticmolecular interaction of graphene to the disease targets. The therapeutic potential of graphene was also studied by changingthe size and the number of layers of the graphene. The experimental results confirm the good therapeutic potential ofthe graphene to combat HIV mediated retroviral infections.

Development of eco-friendly concrete produced with Rice Husk Ash (RHA) based geopolymer

Annadurai, Shalini,Rathinam, Kumutha,Kanagarajan, Vijai Techno-Press 2020 Advances in concrete construction Vol.9 No.2

This paper reports the effect of Rice Husk Ash (RHA) in geopolymer concrete on strength, durability and microstructural properties under ambient curing at a room temperature of 25℃ and 65±5% relative humidity. Rice husk was incinerated at 800℃ in a hot air oven. and ground in a ball mill to achieve the required fineness. RHA was partially added in 10, 15, 20, 25, 30 and 35 percentages to fly ash with 10% of GGBS to produce geopolymer concrete. Test results exhibit that the substitution of RHA in geopolymer concrete resulted in reduced strength properties during initial curing. In the initial stage, workability of GPC mixes was affected by RHA particles due to the presence of dormant particles in it. It is evident from the microstructural study that the presence of RHA particles densifies the matrix reducing porosity in concrete. This is due to the presence of RHA in geopolymer concrete, which affects the ratio of silica and alumina, resulting in polycondensation reactions products. This study suggests that incorporation of rice husk ash in geopolymer concrete is the solution for effective utilization of waste materials and prevention of environmental pollution due to the dumping of industrial waste and to produce eco-friendly concrete.