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Think before use: Sterility checking of culture plates

Nagarajan Prabhusaran, Mahalingam Pramila, Aasaithambi Anupriya
2018 GSC Biological and Pharmaceutical Sciences  
Microbial contaminations in the culture plates are quite common in microbiological laboratory. The preparation of culture plates is an art thereby the scientific principles should be adhered strictly. While preparing the culture plates, chance of contamination is high either due to inadequate sterilization or improper handling. In general, the prepared plates should not use or store at low temperature immediately. The sterility checking is very important before impregnation the plates for
more » ... iological procedures. This study is aimed to analyze the discarding criteria of the contaminated plates either partly or completely. Two sets of nutrient agar plates were prepared and kept for sterility checking overnight at room temperature. The type of contaminants were assessed; thereby colonies on the surface or underneath the surface. Both the sets were kept for another day for the development of contamination in the contaminant free plates recorded on the day 1. The results revealed that two types of contaminants were found in two sets. Set one have the colonies on the surface and no further contamination found on day 2 in the non-contaminated plates indicated that the contamination may occur during plating procedures. Set two have the colonies underneath the surface and contamination developed on day 2 in the non-contaminated plates due to improper sterilization of the glassware and culture media. Thus from this study, it was recommended that the set one plates which are not contaminated are used for further processing, whereas the entire set two should be discarded. The major significance of this work is to understand the importance of sterility checking before using the nutrient plates for culturing.
doi:10.30574/gscbps.2018.5.1.0094 fatcat:vc2gpcptrraifd4cthbgieexna

Harmony Search Algorithm for Minimizing Assembly Variation in Non-linear Assembly

Siva Kumar Mahalingam, Lenin Nagarajan, Sachin Salunkhe, Emad Abouel Nasr, Jõao Paulo Davim, Hussein M.A. Hussein
2021 Applied Sciences  
The proposed work aims to acquire the maximum number of non-linear assemblies with closer assembly tolerance specifications by mating the different bins' components. Before that, the components are classified based on the range of tolerance values and grouped into different bins. Further, the manufacturing process of the components is selected from the given and known alternative processes. It is incredibly tedious to obtain the best combinations of bins and the best process together. Hence, a
more » ... ovel approach using the combination of the univariate search method and the harmony search algorithm is proposed in this work. Overrunning clutch assembly is taken as an example. The components of overrunning clutch assembly are manufactured with a wide tolerance value using the best process selected from the given alternatives by the univariate search method. Further, the manufactured components are grouped into three to nine bins. A combination of the best bins is obtained for the various assembly specifications by implementing the harmony search algorithm. The efficacy of the proposed method is demonstrated by showing 24.9% of cost-savings while making overrunning clutch assembly compared with the existing method. The efficacy of the proposed method is demonstrated by showing 24.9% of cost-savings while making overrunning clutch assembly compared with the existing method proposed by Ganesan et al. (2001). The results show that the contribution of the proposed novel methodology is legitimate in solving selective assembly problems.
doi:10.3390/app11199213 fatcat:3szs5p3y45g63fyiq4fq425p54

Meta-Heuristic Technique-Based Parametric Optimization for Electrochemical Machining of Monel 400 Alloys to Investigate the Material Removal Rate and the Sludge

Vengatajalapathi Nagarajan, Ayyappan Solaiyappan, Siva Kumar Mahalingam, Lenin Nagarajan, Sachin Salunkhe, Emad Abouel Nasr, Ragavanantham Shanmugam, Hussein Mohammed Abdel Moneam Hussein
2022 Applied Sciences  
Electrochemical machining (ECM) is a preferred advanced machining process for machining Monel 400 alloys. During the machining, the toxic nickel hydroxides in the sludge are formed. Therefore, it becomes necessary to determine the optimum ECM process parameters that minimize the nickel presence (NP) emission in the sludge while maximizing the material removal rate (MRR). In this investigation, the predominant ECM process parameters, such as the applied voltage, flow rate, and electrolyte
more » ... ration, were controlled to study their effect on the performance measures (i.e., MRR and NP). A meta-heuristic algorithm, the grey wolf optimizer (GWO), was used for the multi-objective optimization of the process parameters for ECM, and its results were compared with the moth-flame optimization (MFO) and particle swarm optimization (PSO) algorithms. It was observed from the surface, main, and interaction plots of this experimentation that all the process variables influenced the objectives significantly. The TOPSIS algorithm was employed to convert multiple objectives into a single objective used in meta-heuristic algorithms. In the convergence plot for the MRR model, the PSO algorithm converged very quickly in 10 iterations, while GWO and MFO took 14 and 64 iterations, respectively. In the case of the NP model, the PSO tool took only 6 iterations to converge, whereas MFO and GWO took 48 and 88 iterations, respectively. However, both MFO and GWO obtained the same solutions of EC = 132.014 g/L, V = 2406 V, and FR = 2.8455 L/min with the best conflicting performances (i.e., MRR = 0.242 g/min and NP = 57.7202 PPM). Hence, it is confirmed that these metaheuristic algorithms of MFO and GWO are more suitable for finding the optimum process parameters for machining Monel 400 alloys with ECM. This work explores a greater scope for the ECM process with better machining performance.
doi:10.3390/app12062793 fatcat:jh53ibyxxbfuvponmnxrqbqspq

Multi Parametric Voice Assessment: Sri Ramachandra University Protocol

Prakash Boominathan, John Samuel, Ravikumar Arunachalam, Roopa Nagarajan, Shenbagavalli Mahalingam
2012 Indian Journal of Otolaryngology and Head & Neck Surgery  
Emergence of "Voice specialty clinics" in ENT and Speech Language Pathologist (SLP) practice in India necessitates development of standard protocols for assessment and management of voice disorders. Based on recommendations from European Laryngological Society in Dejonckere (Eur Arch Otorhinolaryngol 258:77-82, 2001), a comprehensive voice assessment protocol was adapted for Indian population. This study aimed at verifying the face validity and feasibility of using the developed voice
more » ... protocol in a multi specialty tertiary care hospital. It included: history, clinical examination, visual analysis, perceptual analysis, aerodynamic measures, acoustic analysis and patients' self assessment of voice. The developed protocol was administered on 200 patients with voice concerns and problems. Correlation of self assessment with the assessment by the professionals was done using Kendaul tau_b correlation test. The scores of self assessment did not correlate significantly with acoustic measures. Differences in lab findings and self percept of voice indicated that these two were complementary measures in the protocol. Further, diagnosis and management decisions were arrived through a consensus discussion involving the ENT surgeon, SLP and the patient. Vocal hygiene and voice conservation were advised to all patients. Recommendations for voice therapy and/or surgery were provided based on findings from the protocol. The study demonstrated feasibility of using a comprehensive protocol for effective documentation, comparisons, review, training and treatment planning.
doi:10.1007/s12070-011-0460-y pmid:24533392 pmcid:PMC3918278 fatcat:wxiwk4jeenhddll3hbr73c246m

A Multi-Mode Multi-Coil Coupled Tuned Inductive Peaking ILFD for Low Injected Power with Compact Size

Nagarajan Mahalingam, Kaixue Mar, Kiat Seng Yeo
2019 IEEE Access  
In this paper, a multi-mode magnetically coupled and tuned inductive peaking technique with impedance transforming capability is proposed to achieve a wider operational locking range in the injection locked frequency divider (ILFD) for low injected power levels. Fabricated in 65 nm CMOS process, the proposed ILFD operating at 60 GHz, achieves a locking range of 16.3% from 53.2 to 63 GHz with a low injected power of −10 dBm. Occupying a small area of 0.0288 mm 2 , the ILFD delivers an average
more » ... gle-ended output power of −6 dBm with a dc power consumption of 3.7 mW from a 1.2 V supply voltage. The power efficiency (P out /P dc ) of the proposed ILFD is 6.8%. INDEX TERMS 60 GHz, divide-by-2, direct injection locked frequency divider (ILFD), inductive peaking, multi-coupled coils, multi-mode.
doi:10.1109/access.2019.2915030 fatcat:bskrp3gdjjdqjd57x566kyyj3a

Minimizing Cost of Assembly of an Interrelated Dimensional Chain Product Using ABC Algorithm

Mahalingam Sivakumar, Nagarajan Lenin, Kandasamy Jayakrishna, Natarajan Eswara Prasath, Hao Gao
2021 Mathematical Problems in Engineering  
(d) Identification of new solutions instead of unem- ployed bees e new bees are randomly generated based on roulette wheel selection stated in Nagarajan et al.  ...  considered an artificial bee in the colony. e top out of best food source is considered the total number of assemblies made within the specified assembly specifications. e ABC parameters are assumed based on Nagarajan  ... 
doi:10.1155/2021/9811204 fatcat:mtped4qgjzdvdmi6x3rpm22jfi

Coupled Dual LC Tanks Based ILFD With Low Injection Power and Compact Size

Nagarajan Mahalingam, Kaixue Ma, Kiat Seng Yeo, Wei Meng Lim
2014 IEEE Microwave and Wireless Components Letters  
This letter presents a fully differential injection locked frequency divider using coupled dual LC tanks. The proposed injection locked frequency divide-by-2 divider achieves a wide locking range with low injected power levels. The divider, fabricated in 0.18 SiGe BiCMOS process achieves a locking range of 3.77 GHz with an injected power as low as 16 dBm, a phase noise of 116 dBc/Hz at 10 kHz offset with an input referred phase noise of 109.7 dBc/Hz at 10 kHz offset at 25 GHz, maximum output
more » ... er of 2.44 dBm, efficiency of 18.5% and the dc power consumption is 4.8 mW. Index Terms-Coupled dual LC tanks, divide-by-2, injection locked frequency divider (ILFD), -band, 24 GHz.
doi:10.1109/lmwc.2013.2290217 fatcat:ccgowd2lzjdldknkh56vkrkh7a


Shouxian Mou, Kaixue Ma, Kiat Seng Yeo, Nagarajan Mahalingam, Bharatha Kumar Thangarasu
2012 Progress In Electromagnetics Research C  
A novel 12 GHz VCO designed and fabricated in a 0.18 µm SiGe BiCMOS technology is presented. Strongly magnetic coupled dual LC tanks with fixed and tunable capacitive elements are introduced to extend tuning range and improve phase noise. By hybrid using of varactor tuning, loaded transformer tuning and switched capacitor tuning, the proposed VCO achieves a wide tuning range of 4.3 GHz (36%) and output power of −9 dBm with only 4.5 mW power consumption and only 0.17 mm 2 chip area.
doi:10.2528/pierc11091308 fatcat:g3gam2oypjdtpgdci64sj2zxtq

A Novel Methodology for Simultaneous Minimization of Manufacturing Objectives in Tolerance Allocation of Complex Assembly

Lenin Nagarajan, Siva Kumar Mahalingam, Sachin Salunkhe, Emad Abouel Nasr, Jõao Paulo Davim, Hussein M. A. Hussein
2021 Applied Sciences  
Nagarajan et al. (2018) explained that the distance method is used to combine the two different objective functions into a single one.  ... 
doi:10.3390/app11199164 fatcat:c53j2w5ge5djbauvjta2msnpeu

Optimization of Process Control Parameters for WEDM of Al-LM25/Fly Ash/B4C Hybrid Composites Using Evolutionary Algorithms: A Comparative Study

Nagarajan Lenin, Mahalingam Sivakumar, Gurusamy Selvakumar, Devaraj Rajamani, Vinothkumar Sivalingam, Munish Kumar Gupta, Tadeusz Mikolajczyk, Danil Yurievich Pimenov
2021 Metals  
In this work, wire electrical discharge machining (WEDM) of aluminum (LM25) reinforced with fly ash and boron carbide (B4C) hybrid composites was performed to investigate the influence of reinforcement wt% and machining parameters on the performance characteristics. The hybrid composite specimens were fabricated through the stir casting process by varying the wt% of reinforcements from 3 to 9. In the machinability studies, the WEDM process control parameters such as gap voltage, pulse-on time,
more » ... ulse-off time, and wire feed were varied to analyze their effects on machining performance including volume removal rate and surface roughness. The WEDM experiments were planned and conducted through the L27 orthogonal array approach of the Taguchi methodology, and the corresponding volume removal rate and surface roughness were measured. In addition, the multi-parametric ANOVA was performed to examine the statistical significance of the process control parameters on the volume removal rate and surface roughness. Furthermore, the spatial distribution of the parameter values for both the responses were statistically analyzed to confirm the selection of the range of the process control parameters. Finally, the quadratic multiple linear regression models (MLRMs) were formulated based on the correlation between the process control parameters and output responses. The Grass–Hooper Optimization (GHO) algorithm was proposed in this work to identify the optimal process control parameters through the MLRMs, in light of simultaneously maximizing the volume removal rate and minimizing the surface roughness. The effectiveness of the proposed GHO algorithm was tested against the results of the particle swarm optimization and moth-flame optimization algorithms. From the results, it was identified that the GHO algorithm outperformed the others in terms of maximizing volume removal rate and minimizing the surface roughness values. Furthermore, the confirmation experiment was also carried out to validate the optimal combination of process control parameters obtained through the GHO algorithm.
doi:10.3390/met11071105 fatcat:w4mj4zdp2ze3fe4molehsaz2ea

A 24 GHz low power low phase noise dual-mode phase locked loop frequency synthesizer for 60 GHz applications

Nagarajan Mahalingam, Yisheng Wang, Kaixue Ma, Kiat Seng Yeo, Shou Xian Mou
2014 2014 IEEE MTT-S International Microwave Symposium (IMS2014)  
This paper presents a dual-mode PLL synthesizer used in 60 GHz transceiver supporting both IEEE 802.Had and IEEE 802.IS.3c standards with low power consumption and low phase noise. Fabricated in commercial 0.18 11m SiGe BieMOS process and operated with a single 1.8 V supply, the PLL synthesizer provides output frequencies from 22.5 GHz to 26.:3 GHz with phase noise better than -99.5 dBclHz at 1 MHz offset In both the integer and fractional modes of operation. The PLL synthesizer consumes low
more » ... er of only 42 mW and occupies an area of 1.7 mm x 0.8 mm. Index Terms -24 GHz, 60 GHz, dual-mode, frequency synthesizer, fractional-N, integer-N, phase locked loop (PLL).
doi:10.1109/mwsym.2014.6848405 fatcat:tm7qjweounbqtjgpmo6d52azzy

Optimization of Process Parameters for Turning Hastelloy X under Different Machining Environments Using Evolutionary Algorithms: A Comparative Study

Vinothkumar Sivalingam, Jie Sun, Siva Kumar Mahalingam, Lenin Nagarajan, Yuvaraj Natarajan, Sachin Salunkhe, Emad Abouel Nasr, J. Paulo Davim, Hussein Mohammed Abdel Moneam Hussein
2021 Applied Sciences  
In this research work, the machinability of turning Hastelloy X with a PVD Ti-Al-N coated insert tool in dry, wet, and cryogenic machining environments is investigated. The machinability indices namely cutting force (CF), surface roughness (SR), and cutting temperature (CT) are studied for the different set of input process parameters such as cutting speed, feed rate, and machining environment, through the experiments conducted as per L27 orthogonal array. Minitab 17 is used to create quadratic
more » ... Multiple Linear Regression Models (MLRM) based on the association between turning parameters and machineability indices. The Moth-Flame Optimization (MFO) algorithm is proposed in this work to identify the optimal set of turning parameters through the MLRM models, in view of minimizing the machinability indices. Three case studies by considering individual machinability indices, a combination of dual indices, and a combination of all three indices, are performed. The suggested MFO algorithm's effectiveness is evaluated in comparison to the findings of Genetic, Grass-Hooper, Grey-Wolf, and Particle Swarm Optimization algorithms. From the results, it is identified that the MFO algorithm outperformed the others. In addition, a confirmation experiment is conducted to verify the results of the MFO algorithm's optimal combination of turning parameters.
doi:10.3390/app11209725 fatcat:zox2bo47zbdofmmcpkatihm4ym

An integrated 60GHz low power two-chip wireless system based on IEEE802.11ad standard

Kaixue Ma, Shouxian Mou, Nagarajan Mahalingam, Yisheng Wang, Bharatha Kumar Thangarasu, Jinna Yan, Wanxin Ye, Keping Wang, Wei Meng Lim, Thin Sek Wong, Yang Lu, Wanlan Yang (+22 others)
2014 2014 IEEE MTT-S International Microwave Symposium (IMS2014)  
This paper presents our developed two-chip wireless communication system adhering to the IEEE S02.Had standards with a baseband IC (BBIC) integrated with a low power 60 GHz transceiver SOC (RFIC) and antennas. The novel low power 60GHz RFIC using a sub-harmonic sliding-IF scheme is fully integrated based on low cost SiGe O.IS urn BiCMOS process. The BBIC uses an adaptive time domain equalizer rather than the commonly used frequency domain equalizer to lower the requirements on power consumption.
doi:10.1109/mwsym.2014.6848242 fatcat:ffeiz3hogjeo5d6s6x4y6jkb4a


Tamilselvan Mahalingam, S Nagarajan, Ahsan Chaudhri
2015 International Journal of Management and Social Science Research Review   unpublished
Innovation is indispensable for any organization to stay competitive in the dynamic environment. Competitors are thriving to achieve excellence through anticipation and innovation congruently. In this paper, we tried to draw the attention of academics and practitioners to consider the application of project management tools and techniques to encapsulate the dynamics of project cost and time within the context of innovation. There are several challenges and opportunities exists in the
more » ... of project management practices to achieve organizational strategic goals that leads to innovation in stipulated cost and time. As a matter of fact traditional project management practices needs to be reevaluated and contemporary practices should emerge to extend the current knowledge base in the domain of innovation project management.

Author Index

2021 2021 8th International Conference on Smart Computing and Communications (ICSCC)  
Venkat Raman Nagarajan 275 ............................ Venugopalan Kurupath 323, 362 ........................ Vinayak Bajoria 219 ...........................................  ...  Mahalingam P.R 286 .......................................... Mariam Sunil Varkey 64 ..................................... Mayank Mishra 17 ..............................................  ... 
doi:10.1109/icscc51209.2021.9528286 fatcat:6vytlalqrnhg5gr4ih2inplbwy
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