R. Ravikumar ¹, R. Saravanan ², N. S. Vasanthi ¹, J. Swetha ¹, N. Akshaya ¹, M. Rajthilak ³, K. P. Kannan ¹

Affiliations
1 Deptt. of Biotechnol., Bannari Amman Instiute of Technology, Sathyamangalam- 648401, IN
2 *Coimbatore Instiute of Technology, Coimbatore- 641 006, IN
3 Deptt. of Biotechnol., Bannari Amman Instiute of Technology, Sathyamangalam- 648401

Abstract

A bioremediation method was optimized to degrade and discolour the biomethanated distillery effluent. This phytoremediaion involved a dual stage microbial treatment. During primary treatment, fungal consortium was employed using fluidized film aerobic system (FFAS) and during secondary treatment, algal biomass either in free state (powder form) or in immobilized condition (alginate beads) was employed. The analyzed effluent at the end of FFAS treatment showed a reduction of ~70% in BOD and ~63% in COD without causing any color change. However, at the end of the secondary treatment with algal biomass resulted in a reduction of ~80% in COD and effected 75% decolourization. The optimized conditions for discolouration in the packed bed column were 1.5mm size of immobilized beads, 3.5cm height of packing, 300ml/l spent wash flow rate, 20 H/D ratio of column for immobilized algae and 4cm packing height, 400ml/l spent wash flow rate and 20 H/D ratio of column for algae without immobilization. The efficiency of discolourization by algal biomass remained unaffected by immobilization. An approach of this study could be used to develop a cost effective, ecofriendly biotechnology tool for the bioremediation of spent wash.

Keywords

Biodegradation, Biomethanated Distillery Spent Wash, Industrial Effluent Treatment, Fluidized Film Aerobic System, Phytoremediation.

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Prahalad N. Tengli ¹, C. S. Ramesh ², K. Viswanathan , R. Saravanan ³

Affiliations
1 Mechanical Engg. Deptt., Dr.M.G.R.Educational & Research Institute University, Chennai-600095, IN
2 Mechanical Engg. Deptt., PES Institute of Technology, Bangalore-560085, IN
3 R&D Division, SF Complex, DRDO, Jagdalpur-494001, IN

Abstract

It is not uncommon to find pressure oscillations in large size segmented solid rocket motors. During the static test of segmented solid rocket motor (SRM-3), unanticipated pressure oscillations were seen after some of the propellant has burnt and the oscillations sustained for certain duration of time. The purpose of this paper is to present the results of the analysis carried out on the experimental data using commercial CFD software 'FLUENT' and compare the results with experimental data to find out the cause of the pressure oscillations. Inhibitors are provided for the full web thickness of propellant at the segment joint interfaces to prevent end-burning of propellant at the joints. The char and erosion rate of these inhibitions are lower than the burning rate of the propellant. As burning of the propellant progresses, annular inhibition wall starts projecting above the burning surface of the propellant. These obstacles (inhibition) are acting as wall and sheared gas flow occurs in the rocket motor. CFD analysis was carried out on a quadrilateral mesh for the geometry of SRM-3 at the time of 32 s after ignition when the pressure oscillations peaked. It has been found that the vortex shedding frequency obtained by CFD analysis closely matches with the frequency of pressure oscillations occurring during static testing. Thus, it has been revealed that the obstacle vortex shedding generated by the compartmentalization of the combustion chamber by the protrusion of inhibition at the segment joints was the cause of the pressure oscillations in SRM-3.

Keywords

Vortex Shedding, Segmented Solid Rocket Motor, CFD Analysis, Propellant, Combustion Chamber

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R. Sindhubargavi ¹, M. Yuvasrri Sindhu ¹, R. Saravanan ¹

Affiliations
1 Sastra University, Thanjavur, Tamilnadu, IN

Abstract

With the growth of subscribers in wireless and data communication there is a scarcity of additional bandwidth to meet the demand. For the efficient usage of the spectrum bandwidth we go for a technology which is Cognitive Radio technique. The spectrum holes in the unutilized spectrum are to be used efficiently for the communication for the secondary user. The Cognitive Radio uses spectrum sensing techniques for determining the spectrum holes in the network. In order to improve the efficiency of the energy detection technique it is combined and used with the statistical Principal Component Analysis (PCA) technique. In conventional PCA technique the signal space power to the noise space power does not match with the actual SNR so a PCA correction technique is followed. The correction factor is applied to the noise space power and signal space power to equate it to the actual SNR. The threshold energy required is determined from the modified energy detection technique and the probability of false alarm value. The proposed method is the combination of PCA and energy detection spectrum sensing. The correction factor is applied to the PCA and it clearly defines the process for threshold Energy computation.

Keywords

Cognitive Radio, Energy Detection, Principal Component Analysis, Spectrum Sensing

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S. Jeyaraj ¹, K. P. Arulshri ², P. S. Sivasakthivel ¹, S. Dhasarathy ¹, R. Saravanan ¹, G. Muralidharan ¹

Affiliations
1 School of Mechanical Engineering, SASTRA University, Thanjavur - 613401, Tamil Nadu, IN
2 Department of Mechatronics, Bannari Amman Institute of Technology, Satyamangalam - 638401, Tamil Nadu, IN

Abstract

Objectives: This paper presents an influences of process parameters on micro hardness of electrodeposited Nickel-slag powder composite coating based on Taguchi's experimental design, signal to noise ratio and analysis of variances. Methods: Nickel - slag powder composite coatings are produced by conventional type electro deposition on mild steel substrate. The primary parameters; current density, pH, bath temperature, particle concentration and agitation speed are considered for experimental investigations. The experimental design is framed by L₂₇ orthogonal array of Taguchi's model based on five parameters with three levels. The experiments are conducted in Watt's type nickel bath. Findings: The micro hardness values of coating were determined using Vickers micro hardness tester. The micro hardness of the Ni-Slag coating was obtained in the span of 190 to 358 Hv. The significances of process parameters on micro hardness of coating were investigated with signal to noise ratio and analysis of variances, and ranked by order. It is observed that bath concentration and agitation speed are the most influencing factors on micro hardness. Application: Taguchi's experimental approach reduces the experimental trails and contributing a greater advantage with reduced experimental time and cost of experimentation. Statistical investigations extend the reliability of an experimental work instead of conventional and randomized testing procedures.

Keywords

Analysis of Variance, Composite Coating, Electrodeposition, Microhardness, Orthogonal Array, S-N Ratio.

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Vijay Narayanan ¹, R. Sellamuthu ¹, R. Saravanan ¹

Affiliations
1 Department of Mechanical Engineering, Amrita School of Engineering - Coimbatore, Amrita Vishwa Vidyapeetham University, Coimbatore - 641112, Tamil Nadu, IN

Abstract

Background: Stainless steels are mainly used where prevention of corrosion attack is the main criteria, but low surface hardness and high wear rate are key obstacles to extensive application. Methods: The surface alloying of AISI 304 stainless steel with titanium was carried out using the heat generated from the Gas Tungsten Arc (GTA). Experiments were conducted by varying the GTA parameters and the optimal parameter was determined. Composition of the surface alloyed layer was analysed using atomic emission spectrometer. The Ti alloyed surface layers were characterized using SEM imaging/EDAX analysis. Findings: Composition of the surface alloyed layer was analysed using atomic emission spectrometer and the results confirmed an increase in the Ti content on the surface layer when compared to the composition of the substrate. The EDAX analysis showed that intermetallic alloys are present in the Ti alloyed surface layers. The microhardness was measured using the Vickers microhardness testing machine and the hardness increased from 267.5 HV for the substrate to 2098 HV for the surface alloyed layer. The wear was measured using the pin-on-disk wear tester and the wear rate decreased from 14.78 x 10^-4 mm³/m for the substrate to 1.84 x 10^-4 mm³/m for the surface alloyed layer. The observation of the microstructure revealed that there is grain refinement in the Ti alloyed surface layer. Applications: The modified specimens can be used as medical implants, control rods in nuclear power plants, pump barrels petrochemical industry. This method can be used to improve the properties in specific area of a product.

Keywords

AISI304, GTA, Hardness, Microstructure, Surface Alloying, Ti, Wear Rate.

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R. Saravanan ¹, S. Srihari ¹, A. Arvind ¹, P. Sreeranj ¹, K. S. Dheeraj ¹, R. Sellamuthu ¹, Sanjivi Arul ¹

Affiliations
1 Department of Mechanical Engineering, Amrita School of Engineering - Coimbatore, Amrita Vishwa Vidyapeetham University, Coimbatore - 641112, Tamil Nadu, IN

Abstract

Background/Objectives: The study aims to improve surface properties of aluminium A356 alloy by surface alloying it with nitrided titanium, in a nitrogen environment, using Gas Tungsten Arc (GTA) as heat source. Methods/Statistical Analysis: Nitrided titanium sheets were surface alloyed with cast aluminium A356 blocks, in nitrogen environment, with GTA as heat source for melting. The cross-sectional microstructure of the specimens was studied using inverted metallurgical microscope. Further analysis was carried out using SEM/EDS to identify the formation of nitrides and intermetallic compounds. The hardness of the specimens was measured using Vickers hardness tester and the wear rate was determined using pin-on-disc wear tester. Findings: Microstructure analysis revealed a uniform and granular refined structure in the modified layer compared to the coarse and dendritic structure of the cast block. EDS analysis indicated the formation of hard-intermetallic compounds. The hardness was measured to be highest at the surface of the central fusion zone, with a maximum value of 656 HV while as-cast aluminium block exhibited only 76 HV. The measured wear rate was 10×10^-4 mm³/m for the modified layer, compared to 52×10^-4 mm³/m of the substrate. Alongside, the loss in weight after wear dropped by 4 mg. The coefficient of friction of the modified surface showed a constant trend during the wear-off period. The enhancement in these surface properties is attributed to the formation of nitrides and other intermetallic compounds that in the modified layer during surface alloying. Additionally, the use of GTA as heat source renders the surface alloying process to be economically feasible relative to other employable methods. Applications/Improvements: The devised surface alloying method used to enhance the surface properties of A356 is cheap, flexible and effective and finds intensive application in marine, automotive and manufacturing sectors.

Keywords

A356, Gas Tungsten Arc, Hardness, Nitriding, Surface Alloying, Titanium, Wear Rate.

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Aneesh Ravikumar ¹, R. Sellamuthu ¹, R. Saravanan ¹

Affiliations
1 Department of Mechanical Engineering, Amrita School of Engineering- Coimbatore, Amrita Vishwa Vidyapeetham University, Coimbatore – 641112, Tamil Nadu, IN

Abstract

Objectives: This paper investigates the effect of Cr addition on hardness, tensile properties and wear behaviour of Al-4.5Cu alloy A206. Methodology: The base alloy was melted and stirred well, fine Cr powder added in required amount, in oil fired pit furnace and poured into a permanent cast iron mold. The cast specimens were solution heat treated at 540⁰C for 4 hrs and were aged at 170⁰C for 17 hrs and 20 hrs. The as-cast and aged specimens were subjected to microstructure and EDAX evaluation followed by hardness, tensile and wear testing. Findings: The microstructure analysis and EDAX analysis reported an irregularly distributed polyhedral structures that appear blocky due to the phase formation of Al-Cr-Mn-Fe-Si. The hardness, ultimate tensile strength and yield strength were found to increase, reach a peak value and then decrease upon further chromium addition in aged condition. The wear rate decreased with increasing hardness and coefficient of friction remained constant with time. Application/Improvements: Evaluate the effect of Cr in Al alloys on the mechanical strength and wear properties.

Keywords

Al-Cu Alloy, Cr Addition, Heat Treatment, Tensile Properties, Wear Rate.

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R. Saravanan ¹, R. Sellamuthu ¹, Arjun Nair ¹, Sarat Dev Mangattu ¹, A. Susaritha ¹, S. Shruthilayaa ¹, Vineeth Vasudevan ¹

Affiliations
1 Department of Mechanical Engineering, Amrita School of Engineering – Coimbatore, Amrita Vishwa Vidyapeetham University, Coimbatore - 641112, Tamil Nadu, IN

Abstract

Objective: The main aim of this project is to modify the surface of LM 25 ingot in order to have a refined microstructure, improvement in hardness and in the wear rate of the modified region. Methods: Surface modification of LM 25 is carried out using GTA method. Argon flow was minimised and simultaneously pure nitrogen (99.999%) was introduced into the environment. Microstructural observation was carried out using Zeiss Axiovert 25CA metallurgical microscope and the hardness was measured using Mitutoyo Vicker’s hardness testing machine. Wear test was carried out for the substrate and the modified region using pin-on-disc wear tester. EDAX analysis was carried out to find the presence of intermetalic compounds. Findings: From the microstructure, it was observed that there is grain refinement in the modified region. The hardness for the substrate was found to be 80.6 HV and 764.4 HV for the modified region. The wear rate in the substrate was 49.34x10^-4 mm³/m and 7.9x10^-4 mm³/m for the modified region. As the hardness increases, wear rate decreases. EDAX report confirms the presence of intermetalic compound in the form of silicon nitride (Si₃N₄). The presence of the silicon nitride is not reported previously using GTA as heat source on surface modified LM25. The increase in the hardness and decrease in the wear rate is attributed to the presence of silicon nitride in the surface. Application/Improvements: Due to the presence of silicon nitride it can be used as an insulator and chemical barrier in electrical circuits etc. It can also have wider automobile and aeronautics applications as its hardness has increased.

Keywords

GTA, Hardness, Microstructure, Surface Modification, Wear Rate.

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R. Saravanan ¹, P. Jawahar ², T. Francis ², B. Ahilan ², R. Santhakumar ², A. Anand ³

Affiliations
1 Regional Centre of Central Marine Fisheries Research Institute, Mandapam Camp, Ramanathapuram District - 623 520, Tamil Nadu, IN
2 Fisheries College and Research Institute, Thoothukkudi – 628 008, Tamil Nadu, IN
3 Regional Remote Sensing Centre–Central (ISRO), Nagpur - 440 010, Maharashtra, IN

Abstract

The present study was conducted to find out whether the abiotic factors in Gulf of Mannarviz., Sea Surface Temperature (SST) and Day light photoperiod would have an effect on the Gonado somatic index of the dominant sea urchin species Salmacis virgulata. A sampling survey for 20 months was conducted from October-2013 to May-2015 in Vedalai landing centre, along the Gulf of Mannar. The freshly collected sea urchin were brought to Mandapam CMFRI and their Gonado Somatic Index (GSI) was estimated. The remote sensing data of the SST from Gulf of Mannar sourced from ICOADS and the daylight photoperiod were compared with the GSI data for 20 months in order to assess the synchrony among the three parameters. The pearson correlation coefficient of the association among the GSI, SST and Photoperiod revealed that there was no significant correlation (p>0.001). The result of the present study revealed that the Gonado Somatic Index of S. virgulata is independent of abiotic factors, which is in contrast to the temperate sea urchin species, where SST and Photoperiod play a major role in gonadal development.

Keywords

Gonad Index, Gulf of Mannar, Sea Urchin, Salmacis

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Sitha Sivaranjani ¹, R. Saravanan ¹

Affiliations
1 School of Computing, SASTRA University, Thanjavur - 613401, Tamil Nadu, IN

Abstract

Objectives: A 16-bit carry look ahead adder is implemented in domino CMOS logic is presented in this paper. The proposed work comprises of two separate 8-bit carry chains. Statistical Analysis: This is evaluated using TANNER EDA tool. The schematics are drawn in s-edit, netlists are generated using T-spice and the waveforms are verified using waveform viewer or w-edit. Layouts can also be created using SDL (Schematic Drawn Layout), by importing netlist in L-edit. Findings: Due to the split carry chains in the adder, the speed of computation is increased, at the cost of area, when compared with ordinary carry look ahead adder. As we know that the use of domino logic reduces the power consumption, but as switching occurs many times power consumption is increased, that is the switching power of the system is increased. Applications: In VLSI system reducing the multipliers and increasing the adders is the main factor, thus in place of those adders if this split carry adders are used, the speed will be increased further.

Keywords

Domino Logic, Fast Addition, 16-bit Carry Look Ahead Adder, Split Carry, Tanner EDA.

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M. Deepika ¹, R. Saravanan ¹

Affiliations
1 School of Computing, SASTRA University, Thanjavur - 613401, Tamil Nadu, IN

Abstract

Wave Pipelining has been used in order to reduce the area without degrading its performance and also to improve the speed. In pipelining the throughput is achieved with the compensation of area and the critical path will be same as the original architecture. While considering of larger circuits the area places an important role where the cost is a major issue. Hence in order to reduce the area the latches are removed which produces the technique of wave pipelining. The concept of Wave Pipelining optimize the area and speed when compared to the pipelining architectures. Thus the Wave Pipelining is applied in the FFT architecture for achieving less area. The FFT pipelined architecture is based on splitting the architecture by stages. Each stage is evaluated with effective structure. It’s noted that by using the internal clock which increases both speed and reduces clock loads the number of gates used in the pipelined structure is reduced in using wave pipelining. The Wave Pipelining technique have to be implemented in a 32-bit FFT Pipelined architecture which is suitable for a digital signal processing applications for image processing and for conversion of frequency domain to time domain. And to compare the area and speed of the WP architecture and pipelined architecture.

Keywords

DIF, DIT, Multiplier, Pipelining, 32-bit FFT Processor, Wave Pipelining (WP).

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P. Shreya ¹, R. Saravanan ¹

Affiliations
1 School of Computing, Sastra University, Thanjavur – 613401, Tamil Nadu, IN

Abstract

Background: Digital multipliers, the most important part which is used to implement most of the digital processing and arithmetic applications such as Filters, FFT’s, etc. As the rapid developments in technology required, many researchers are going to design multipliers which offers an efficient design aspect with respect to the speed and power consumption. Statistical analysis: Multipliers are the key functional units in various applications. The transistor speed is reduced due to bias temperature instability effects. When this effect extends in distant future, the system may not work properly due to timing infraction. Findings: The overall performance of these systems depends on the multiplier’s throughput. The Negative Bias Temperature Instability (NBTI) effect occurs when a pMOS transistor is under negative bias (Vgs = −Vdd), which results the increase in the threshold voltage of the pMOS transistor, hence the delay in the multiplier is increased. In the same way, positive bias temperature instability, occurs when an nMOS transistor is under positive bias. Both the temperature effects decrease the transistor speed, in the long run, the system may fail due to timing violations. Usually consummation of a system depends on the throughput of the multiplier. So it is important to adopt a reliable high performance multiplier. The multiplier is able to attenuate the performance degradation due to aging. Improvement: Hence, the objective of the project is to design a high speed and power efficient multiplier to increase the performance of the device. Design of Multiplier circuit using Adaptive Hold Technique is proposed. By using AHT circuit we can reduce the NBTI and Positive Bias Temperature Instability(PBTI) effects, hence performance will be increased and the aging effects will be reduced. The proposed technique is done using Xilinx 14.7 tool. The code is simulated and synthesized and comparison results are made based on the performance of the multipliers with and without AHT.

Keywords

Aging, Attenuate, Hold Logic, Temperature Instability, Throughput.

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