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1

Underwater Acoustic Sensor Node Scheduling using an Evolutionary Memetic Algorithm

Sivakumar V., Rekha D.

Journal of Telecommunications and Information Technology

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2018

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nr 1

88--94

EN

Underwater Acoustic Sensor Networks (UWASNs) play an important role in monitoring the aqueous environment which has created a lot of interest for researchers and scientists. Utilization of underwater acoustic sensor node (UASN) scheduling for transmission remains, due to the limited acoustic bandwidth available, a challenge in such an environment. One of the methods to overcome this problem is to efficiently schedule UASN data using time division multiple access (TDMA) protocols the parallel transmissions, simultaneously avoiding interference. The paper shows how to optimize the utilization of acoustic sensor node bandwidth by maximizing the possible node transmissions in the TDMA frame and also by minimizing the node's turnaround wait time for its subsequent transmissions by using an evolutionary memetic algorithm (MA). The simulation of MA-TDMA proves that as the size of the network increases, every node in UWASN transmits with an average minimal turnaround transmission time. It also proves that as the TDMA cycle repeats, the overall network throughput gets maximized by increasing the possible node transmissions in the MA-TDMA frame.

2

Performance evaluation of chemical coagulation process to treat bagasse wastewater : modeling and optimization

Thirugnanasambandham K., Sivakumar V., Shine K.

Polish Journal of Chemical Technology

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2016

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Vol. 18, nr 1

99--104

EN

In this present study, chemical coagulation process (CC) treatment process was investigated under different conditions such as pH, ferric chloride dose, agitation time and settling time to treat bagasse wastewater using response surface methodology (RSM). The outcomes were evaluated using Pareto analysis of variance (ANOVA) and second order polynomial models were created with the aim of being able to predict the responses. Ideal conditions were observed to be as per the following: agitation time of 25 min, pH of 7, ferric chloride dose of 6 g/L and settling time of 60 min. Under these conditions, turbidity removal of 62%, COD removal of 67%, TDS removal 53% and sludge production of 32 mL/L were obtained with operating cost of 3.50 Rupee/L. The mechanism of CC was analyzed using XRD spectrum and founds to be adsorption.

3

Distribution and invasiveness of a colonial ascidian, Didemnum psammathodes, along the southern Indian coastal water

Jaffar H. A., Akram A. S., Arshan M. L. K., Sivakumar V., Tamilselvi M.

Oceanologia

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2016

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No. 58 (3)

212--220

EN

Ascidians are well known worldwide for their rapid invasions and also for the presence of potential biomedical molecules. Members of the family Didemnidae are widely distributed in tropical waters and they are reported to be among the families possessing rich bioactive compounds. Didemnum psammathodes has a cosmopolitan distribution in tropical waters. The growing evidence of multifarious potential and ever increasing invasion of this species accentuated the need for additional research into its diversity and distribution for sustainable utilization and conservation. The present study was intended to focus on distribution and invasiveness of colonial ascidian, D. psammathodes, along the southern Indian peninsular waters. The present data are based on our own observations made during 2012–2014 period and also on the published and unpublished records of the last 20 years. Out of 45 stations surveyed, D. psammathodes was encountered at a maximum of 41 stations and was found to be more abundant in Hare Island (n = 42), North Break Water (n = 38) and Vizhinjam bay (n = 32). This species was absent at four different stations. Catch per unit effort was higher (19.6) in Hare Island followed by NBW (16.0) and Vizhinjam bay (6.8). The highest number of colonies (136) was observed in calcareous stones, followed by embedded rocks (54) and molluscan shells (33). Hydrographical parameters showed no significant differences between the stations (p < 0.005). It is concluded that D. psammathodes has the potential to invade most of the stations and its distribution was not influenced by hydrographical parameters rather than substrates.

4

Kinetic, Equilibrium and Thermodynamic studies on the removal of Cr(VI) by activated carbon prepared from Cajanus Cajan(L) Milsp seed shell

Thamilarasu P., Kumar Vijaya G., Tamilarasan R., Sivakumar V., Karunakaran K.

Polish Journal of Chemical Technology

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2011

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Vol. 13, nr 4

1-7

EN

This paper presents the feasibility of the removal of hexavalent chromium ions from aqueous solutions by using activated carbon prepared from Cajanus Cajan(L) Milsp. It was carbonized and activated by treating it with concentrated sulfuric acid followed by heating for 5 h at 500oC. Batch adsorption experiments were carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage and temperature. The experimental data fi tted well to the Freundlich isotherm. The thermodynamic parameters such as ΔHo, ΔSo, and ΔGo were calculated, which indicated that the adsorption was spontaneous and endothermic in nature. The adsorbent used in this study was characterized by FT-IR and SEM before and after the adsorption of metal ions. The results indicate that Cajanus Cajan(L) Milsp can be employed as a low cost alternative and commercial adsorbents in the removal of chromium (VI) from water and waste water.

5

COD reduction studies of paper mill effluent using a batch recirculation electrochemical method

Kannadasan T., Sivakumar V., Ahmed Basha C., Parwate A. V., Senthilkumar K., Kannan K.

Polish Journal of Chemical Technology

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2011

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Vol. 13, nr 3

37-41

EN

The conventional method of treating pulp and paper mill effluent involves the biological oxidation by bacterial action of aerobic and anaerobic conditions and aerobic lagooning method, which are less efficiency of removing COD. To overcome the drawbacks of the existing treatment process, in the present work an attempt has been made to study the electro oxidative destruction of the pulp and paper mill effluent using an electrochemical method and the effect of various parameters such as concentration of supporting electrolytes, current densities, flow rates of electrolyte and reservoir volumes of the effluent were conducted. From the experimental results it is observed that the rate of reduction of COD of the effluent increased with an increase in the supporting electrolyte (sodium chloride) concentration, current density where as it decreased with increase in the reservoir volume and the flow rate of electrolyte. The residence time distributions studies have also been conducted to study the behavior of the electrochemical reactor.

6

Prediction of gas holdup in the three-phase fluidized bed: air/Newtonian and non-Newtonian liquid systems

Sivakumar V., Senthilkumar K., Kannadasan T.

Polish Journal of Chemical Technology

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2010

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Vol. 12, nr 4

64-71

EN

The application of the three-phase fluidization technology in wastewater treatment and other biochemical processes has been regularly addressed in the past decades. For the design and development of the threephase fluidized bed reactors, knowledge of the hydrodynamic parameter such as gas holdup is essential and hence in this paper an attempt has been made to study the effect of fundamental and operating variables on gas holdup. On the basis of the experimental results, a unified correlation has been developed to predict gas holdup in the fluidized bed using the Newtonian and the non-Newtonian liquids. The experimental results showed good agreement with those predicted according to the developed correlation.