Qualification: 
Ph.D
Email: 
n_madhumohan@cb.amrita.edu

Dr. Madhu Mohan N. joined Amrita School of Engineering in the year 2010. He did his Bachelor’s degree in Electronics and Communication Engineering from NSS College of Engineering, Palakkad and Master’s degree in Instrumentation from IIT Madras. He completed his Doctoral dissertation in Instrumentation from IIT Madras.

Prior to coming Amrita, he served as a Senior Research Fellow in a DST sponsored project, Assess Dermal Perfusion by means of Thermography and many other funded projects at IIT Madras. He is the key player to setting up the Virtual Instrumentation Laboratory at IIT Madras.

Dr. Madhu is a keen researcher, having more than 20 paper publications in international journals and conferences. He is also the coordinator of postgraduate programs in Biomedical Engineering.

Publications

Publication Type: Conference Paper

Year of Publication Publication Type Title

2015

Conference Paper

A. E. Anoop, Dr. Madhu Mohan N., and Guruvayurappan, K., “Simulation of a multi-strip blood glucometer”, in IEEE Region 10 Annual International Conference, Proceedings/TENCON, 2015, vol. 2015-January.[Abstract]


Normal blood glucose levels are tightly regulated in the human body, in the range of 70-150 mg/dL. With the increasing awareness that uncontrolled diabetes plays a significant role in the onset and progress of other diseases, severely diabetic patients are being advised to closely monitor their haemoglucose levels, as often as four times every day. This is done in a home environment, by means of a glucometer and enzyme-coated test strips, having high specificity for glucose. The test strips are expensive and specific to the glucometer of a particular manufacturer, which implies that a patient is tied to one glucometer, making it economically unviable, especially in a developing country like India. Efforts are being made to develop a portable glucometer, which would accommodate, if not all, most of the commercial glucose test strips, available in the market today. As a first step, three of the most widely used test strips have been characterised and a circuit has been designed to obtain their current responses. This paper describes the simulation of the circuit and discusses the results obtained. © 2014 IEEE.

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2015

Conference Paper

K. R. Sandra, Anusha, A. S., Dr. Madhu Mohan N., and George, B., “Simulation study of a contactless, capacitive ECG system”, in IEEE Region 10 Annual International Conference, Proceedings/TENCON, 2015, vol. 2015-January.[Abstract]


The electrocardiogram (ECG) is one of the primary sources of information for assessing cardiovascular function. Conventional ECG systems are not suitable for continuous, long-term monitoring. Contactless measurement of ECG using capacitive sensors is emerging as an attractive alternative. One of the disadvantages of a contactless system is that the signal quality is poor as far as the clinical acceptance of the system is concerned. The contactless ECG signal typically contains a relatively large amount of dc, due to electrode offset or artifacts, which would drive the front end of the high-gain amplifier into saturation. Hence, what is required is a circuit that would effectively block dc while coupling the differential ac signal. A circuit developed for conventional ECG systems has been made use of, for this purpose. This paper describes the simulation and analysis of a contactless ECG monitoring system, using capacitive electrodes, with an ac-coupled front end for effective dc decoupling. The performance of the circuit is studied for different material and thicknesses of clothing. © 2014 IEEE.

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2014

Conference Paper

K. R. Sandra, Anusha, A. S., Dr. Madhu Mohan N., and George, B., “Simulation study of a contactless, capacitive ECG system”, in TENCON 2014 - 2014 IEEE Region 10 Conference, 2014.[Abstract]


The electrocardiogram (ECG) is one of the primary sources of information for assessing cardiovascular function. Conventional ECG systems are not suitable for continuous, long-term monitoring. Contactless measurement of ECG using capacitive sensors is emerging as an attractive alternative. One of the disadvantages of a contactless system is that the signal quality is poor as far as the clinical acceptance of the system is concerned. The contactless ECG signal typically contains a relatively large amount of dc, due to electrode offset or artifacts, which would drive the front end of the high-gain amplifier into saturation. Hence, what is required is a circuit that would effectively block dc while coupling the differential ac signal. A circuit developed for conventional ECG systems has been made use of, for this purpose. This paper describes the simulation and analysis of a contactless ECG monitoring system, using capacitive electrodes, with an ac-coupled front end for effective dc decoupling. The performance of the circuit is studied for different material and thicknesses of clothing. More »»

2014

Conference Paper

A. E. Anoop, Dr. Madhu Mohan N., and Guruvayurappan, K., “Simulation of a multi-strip blood glucometer”, in TENCON 2014 - 2014 IEEE Region 10 Conference, 2014.[Abstract]


Normal blood glucose levels are tightly regulated in the human body, in the range of 70-150 mg/dL. With the increasing awareness that uncontrolled diabetes plays a significant role in the onset and progress of other diseases, severely diabetic patients are being advised to closely monitor their haemoglucose levels, as often as four times every day. This is done in a home environment, by means of a glucometer and enzyme-coated test strips, having high specificity for glucose. The test strips are expensive and specific to the glucometer of a particular manufacturer, which implies that a patient is tied to one glucometer, making it economically unviable, especially in a developing country like India. Efforts are being made to develop a portable glucometer, which would accommodate, if not all, most of the commercial glucose test strips, available in the market today. As a first step, three of the most widely used test strips have been characterised and a circuit has been designed to obtain their current responses. This paper describes the simulation of the circuit and discusses the results obtained. More »»

2011

Conference Paper

K. A. Reddy, George, B., Dr. Madhu Mohan N., and Kumar, V. J., “A novel method for the measurement of oxygen saturation in arterial blood”, in IEEE International Instrumentation and Measurement Technology Conference, 2011.[Abstract]


A novel and noninvasive method of estimation of oxygen saturation in arterial blood (SpO2), employing the popular photoelectric plethysmographic (PPG) principle, is presented here. Based on a refined model for the attenuation of light in a PPG sensor, a simple method of computation of SpO2 that is not influenced by interfering parameters of a patient such as skin colour and quantum of intervening tissue between the source and the detector in a PPG sensor as well as sensor dependent parameters such as source intensity and detector sensitivity is identified. Preliminary results obtained on a prototype pulse oximeter, built and tested, demonstrate the practicality of the proposed method. More »»

2010

Conference Paper

S. Gopalakrishna, Jayashankar, V., Jagadeesh, K. V., and Dr. Madhu Mohan N., “Online assessment of winding deformation based on optimised excitation”, in 2010 IEEE International Workshop on Applied Measurements for Power Systems, 2010.[Abstract]


On line assessment of winding deformation in a power transformer can be performed via a bushing tap excitation with optimized high frequency excitation. A benchmark layer winding is used to validate the use of the specific high frequency excitation. Axial displacement, compression and buckling of the winding are simulated and the changes identified. Measurements are performed on a voltage transformer to verify the suitability of the technique. The procedure will result in a considerably shorter time for measurement. More »»

2009

Conference Paper

Dr. Madhu Mohan N. and V. Kumar, J., “Direct digital converter for a single active element resistive sensor”, in 2009 IEEE Instrumentation and Measurement Technology Conference, 2009.[Abstract]


A direct digital converter that provides a digital output, proportional to the measurand being sensed by a single active element resistive sensor is presented in this paper. To accomplish this task, the structure and the switching sequence of a conventional dual slope, analog to digital converter (DSADC) is appropriately altered so that the altered DSADC accepts the resistance of the sensor as an integral part and provides a digital output that is linearly proportional to the physical quantity being sensed by the resistive sensor. Since the output of the dual slope resistance to digital converter (DSRDC) is dictated only by the magnitudes of a pair of DC reference voltages, a fixed value resistor and the transformation constant of the sensor, the error in the output is minimal. Hence, a high level of linearity and accuracy is achieved. Simulation studies establish the efficacy of the proposed scheme. More »»

2009

Conference Paper

Dr. Madhu Mohan N. and V. Kumar, J., “Virtual instrument for assessing dermal perfusion”, in 2009 IEEE Instrumentation and Measurement Technology Conference, 2009.[Abstract]


Determining the extent of dermal perfusion is crucial in assessing the healing of chronic wounds, of the kind encountered in diabetic ulcers and burns. An automated, contact-less, non-invasive means of analyzing the dermal perfusion in selected areas would be useful in this process. Such a technique is presented in this paper. It describes a virtual instrument developed for acquiring a series of visual and near infrared images of the affected area and subsequent off-line analysis and presentation of the results. The virtual instrument has been tested with satisfying results for stimulated dermal perfusion and inhibition. More »»

2009

Conference Paper

Dr. Madhu Mohan N., Mariappan, L., and V. Kumar, J., “A novel signal processing method for the measurement of venous refilling time”, in 2009 IEEE Instrumentation and Measurement Technology Conference, 2009.[Abstract]


Methods in vogue for the measurement of venous refilling time (VRT), based on the photo-plethysmographic (PPG) principle, employ a feedback compensation technique to remove the influence of the colour of a patient's skin. Hence these methods require a “standardization phase” for every measurement. Based on an appropriate model for the propagation of light through skin and tissue, a novel signal processing method is proposed for the measurement of VRT. The proposed technique renders the measurement of VRT independent of not only the colour of the skin of a patient but also of source intensity and detector sensitivity. Test results obtained from a prototype unit, built under the LabVIEW virtual environment, establish the validity of the model and the proposed signal processing technique. More »»

2008

Conference Paper

Dr. Madhu Mohan N. and Kumar, V. J., “Contact-less, Multi-Spectral Imaging of Dermal Perfusion”, in 2008 IEEE Instrumentation and Measurement Technology Conference, 2008.[Abstract]


Photoplethysmography (PPG) has come to be accepted as a common, non-invasive method for measuring the level of oxygen saturation in arterial blood. This paper describes a variation of the accepted PPG technique, to provide a contact-less and non-invasive method of characterizing dermal perfusion. It employs a 3-CCD, multi-spectral camera, to image the selected area. The acquired images are analysed by making use of the fact that the absorption co-efficient of oxygenated blood is more in the infra-red (IR) region of the spectrum, when compared to the red region. This fact is utilised to characterize the extent of dermal perfusion in the selected area of the skin. More »»

2008

Conference Paper

Dr. Madhu Mohan N., George, B., and Kumar, V. J., “A Sigma-Delta Resistance to Digital Converter Suitable for Differential Resistive Sensors”, in Instrumentation and Measurement Technology Conference Proceedings, 2008. IMTC 2008. IEEE, 2008.[Abstract]


This paper presents a novel resistance-to-digital converter (RDC) suitable for differential resistive sensors. The proposed RDC provides a digital output linearly proportional to the parameter being sensed by a differential resistive sensor not only for differential resistive sensors possessing linear characteristic but also for sensors possessing inverse characteristic. The proposed RDC is based on the sigma-delta type analog-to-digital converter (Sigma-Delta ADC) principle and hence possesses all the advantages and limitations of a Sigma-Delta ADC. Experimental results on a prototype built and tested gave a worst case error < 0.15 %, establishing the efficacy of the proffered RDC. More »»

2008

Conference Paper

K. A. Reddy, George, B., Dr. Madhu Mohan N., and Kumar, V. J., “A Novel Method of Measurement of Oxygen Saturation in Arterial Blood”, in Instrumentation and Measurement Technology Conference Proceedings, 2008. IMTC 2008. IEEE, 2008.[Abstract]


Existing methods of pulse oximetry rely on a calibration curve for the estimation of oxygen saturation in arterial blood (SpO2). A novel method of computation of SpO2 that does not require the use of a calibration curve is presented in this paper. Based on a model proposed here for the propagation of light through skin, tissue, bone and blood, suitable processing steps are identified so that the analytical expression derived for the estimation of SpO2 becomes free of patient and sensor dependent parameters. Experimental results presented herein establish the efficacy of the proposed method. More »»

2007

Conference Paper

Dr. Madhu Mohan N., George, B., and Kumar, V. J., “Dual Slope Resistance to Digital Converter”, in Instrumentation and Measurement Technology Conference Proceedings, 2007. IMTC 2007. IEEE, 2007.[Abstract]


A dual slope resistance to digital converter applicable to differential resistive sensors is presented. A dual slope digital converter is appropriately modified so that it accepts directly the resistive elements of a differential resistive sensor and provide a digital output that is linearly proportional to the physical quantity being sensed by the sensor. High accuracy is easily obtained since the output is decided only by a pair of dc reference voltages and the transformation constant of the sensor. Sensitivity analysis shows that the effect of circuit parameter variations on the output is minimal. The efficacy of the proposed scheme is clearly demonstrated by the test results obtained on a prototype. More »»

2006

Conference Paper

A. K. Reddy, J. Bai, R., George, B., Dr. Madhu Mohan N., and V. Kumar, J., “Virtual Instrument for the Measurement of Haemo-dynamic Parameters Using Photoplethysmograph”, in Instrumentation and Measurement Technology Conference, 2006. IMTC 2006. Proceedings of the IEEE, 2006.[Abstract]


This paper presents the design and development of a virtual instrument for the measurement of haemodynamic parameters namely, pulse rate and oxygen saturation in arterial blood based on the popular photoplethysmographic (PPG) principle. A clip-on sensor, housing red and infrared (IR) light emitting diodes and suitable photo detectors is developed. The sensor is interfaced to a PC utilizing the audio channel of the sound card, thus dispensing with expensive analog to digital converter hardware. Since the frequency response of the audio channel is not suitable for the PPG waveforms of red and IR, FM modulation and demodulation are employed. An empirical relationship is developed for the computation of the oxygen saturation in arterial blood using the red and IR PPG data and the well-known and well-established extinction coefficients of haemoglobin with and without oxygen. Data acquisition and processing are accomplished under LabVIEW virtual environment More »»

2006

Conference Paper

Dr. Madhu Mohan N., George, B., and Kumar, V. J., “Virtual Instrument for Testing of Current and Voltage Transformers”, in Instrumentation and Measurement Technology Conference, 2006. IMTC 2006. Proceedings of the IEEE, 2006.[Abstract]


Instrument transformers, namely, current and voltage (potential) transformers are characterized by their ratio and phase errors. A novel virtual instrument that determines the errors of an instrument transformer using a quasi-balance technique is proposed in this paper. Operating on the secondary quantities of the test and standard transformers, two independent quasi-balance conditions are obtained. The errors of the test transformer are then determined using the two quasi-balance settings alone. The method inherently possesses all the advantages of an ac bridge but dispenses with the tedious iterative balancing. A prototype unit built and tested establishes the practical viability of the proposed technique More »»

2005

Conference Paper

V. J. Kumar, Dr. Madhu Mohan N., and Murti, V. G. K., “Digital Converter for Push-Pull Type Resistive Transducers”, in 2005 IEEE Instrumentationand Measurement Technology Conference Proceedings, 2005.[Abstract]


A direct resistance-to-digital converter (RDC) suitable for push-pull type resistive transducers is proposed. The push-pull resistive transducer forms an integral part of an integrating type analogue-to-digital converter and provides a digital output proportional to the physical quantity being sensed. It has been established that with an additional set of integration, automatic offset compensation can be achieved. Test results on a prototype demonstrate the efficacy of the proposed method More »»

Publication Type: Journal Article

Year of Publication Publication Type Title

2015

Journal Article

T. L. Blundell, Dr. Madhu Mohan N., and , “Chopin: A web resource for the structural and functional proteome of Mycobacterium tuberculosis”, 2015.

2015

Journal Article

M. Mohan, Mohan, N., Chand, D. Kumar, and Dr. Madhu Mohan N., “Self-assembled gold nanofilms as a simple, recoverable and recyclable catalyst for nitro-reduction”, J. Mater. Chem. A, vol. 3, pp. 21167-21177, 2015.[Abstract]


Hexaazamacrocycle (L) stabilized gold nanoparticles (AuNPs) were prepared by combining L with HAuCl4[middle dot]3H2O in a variety of alcohol-water (1 : 1) mixtures. The dual roles of L as a reducing and stabilizing agent were exploited for the synthesis of AuNPs under the optimized ratio of L to Au3+ (2 : 1). Self-assembled gold nanofilms (AuNFs) were constructed at liquid-liquid interfaces by adding equal volumes of hexane to the dispersions of AuNPs in the alcohol-water systems. The nanofilms were formed spontaneously by shaking the two-phase mixture for a minute followed by standing. The alcohols explored for the self-assembly phenomenon were methanol{,} ethanol{,} i-propanol and t-butanol. The systems containing methanol or t-butanol resulted in AuNFs at the interfaces{,} whereas the other two alcohols were found not suitable and the AuNPs remained dispersed in the corresponding alcohol-water medium. The AuNFs prepared under suitable conditions were coated on a variety of surfaces by the dip and lift-off method/solvent removal approach. The AuNFs were characterized by UV-vis{,} SEM{,} TEM{,} AFM and contact angle measurement techniques. A coated glass-vial or cuvette was used as a catalytic reservoir for nitro-reduction reactions under ambient and aqueous conditions using NaBH4 as the reducing agent. The reduced products (amines) were extracted by aqueous work-up using ethyl acetate followed by evaporation of the organic layer; the isolated products required no further purification. The catalyst was recovered by simply decanting the reaction mixture whereupon the isolated catalyst remained coated inside the vessel. The recovered catalyst was found to be equally efficient for further catalytic cycles. More »»

2015

Journal Article

F. John and Dr. Madhu Mohan N., “Decision Making Styles of Young Adult Consumers in Chennai City: an Exploratory Study of Gender Differences”, 2015.[Abstract]


As India has undergone dramatic change in its retail markets since economic liberalization in 1992, the decision making by consumers is becoming increasingly complex. Prior to liberalization consumers in India had restricted choice in the retail environment reflecting the closed nature of their marketing systems. But with liberalization the consumers now experience a more modern marketplace and the unprecedented abundance of brands and retail outlets has created a massive array of choice for consumers coupled with the rise in the population of young consumers. Hence, in this study an attempt was made to analyse the decision making styles of young adult consumers in Chennai city and to explore the differences if any, in the decision making style of the gender with regard to the variables taken for the study More »»

2014

Journal Article

F. John and Dr. Madhu Mohan N., “An Empirical Study on Quality of Work Life: in RANE (Madras) Ltd.”, Sumedha Journal of Management, vol. 3, p. 4, 2014.[Abstract]


Quality of work life is a multidimensional concept implying a concern for the members of an organization. The basis underlying quality of work life is the humanization of work which means developing a work environment that ensures dignity to the employees stimulates his creative abilities and facilitates self growth. The focus of this paper concerns the study of Quality of Work Life for the employees of an automobile component manufacturing company. The aim of this paper is to determine whether the employees are satisfied with the quality of work life and it is found that the quality of work life of executives in Rane (Madras) Ltd is good. More »»

2013

Journal Article

K. Raghubabu, Dr. Madhu Mohan N., Kalyanaramu, B., Ramdas, C., and Rao, M. N., “Development of new visible specrophotometric determination of tiaprofenic Acid in bulk and formulations”, Asian J Pharm Clin Res, vol. 6, pp. 77–79, 2013.[Abstract]


A simple and sensitive visible spectrophotometric method has been developed for the determination of Tiaprofenic acid from its bulk drug and formulations. This method involves charge-transfer complex formation of tiaprofenic acid with in situ oxidized form haemaetin obtained from haematoxylin and chloramin-T (CAT) in the presence of pH 7 buffer solution, to form purple colored species of maximum wavelength at 555 nm. Regression analysis of Beer's law plot showed good correlation in the concentration range of 16-80μg/ml. The proposed method is applied to commercial available tablets and the results are statistically compared with those obtained by the UV reference method and validated by recovery studies. The results are found satisfactory and reproducible. The method is applied successfully for the estimation of the tiaprofenic acid in formulations without the interference of excipients. The method offers the advantages of rapidity, simplicity and sensitivity and can be easily applied to resource-poor settings without the need for expensive instrumentation and reagents. More »»

2013

Journal Article

M. Thakur, Singh, S. K., Shukla, M., Sharma, L. K., Dr. Madhu Mohan N., and , “Identification of Galliformes through Forensically Informative Nucleotide Sequencing (FINS) and its Implication in Wildlife Forensics”, J Forensic Res S, vol. 3, p. 2, 2013.[Abstract]


Galliformes are hunted for the demand of their attractive feathers and to supply a cheap animal food for the rural communities. In such cases, species identification through visual inspection of the meat or based on feather morphometrics is a challenging task for the law enforcement agencies to enforce the Wildlife Protection Act (WPA). Here, we extracted DNA from the individual feathers of unknown species encountered during field surveys and two mitochondrial genes (12S rRNA and Cytochrome b) were amplified using universal primers for species identification. Most homologous sequences were retrieved using NCBI-BLAST for each generated sequence of both the genes. Neighbor-Joining trees based on Kimura 2 parameter distance matrices in FINS analysis identified the species from the individual feather with strong bootstrap support. Nine species specific polymorphic sites were found in the partial sequence of Cytochrome b gene that differentiated Pavo cristatus to Pavo muticus imperator. Our study highlighted the importance of feathers in identifying the species and their applicability in wildlife offence cases using FINS approach.

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2013

Journal Article

N. Sharma, Dr. Madhu Mohan N., Bhalla, A., Sharma, A., and Singh, S., “Changing Pattern of Epidemic Dropsy in North India”, Asia Pacific Journal of Medical Toxicology, vol. 2, pp. 87–91, 2013.[Abstract]


Background:Epidemic dropsy occurs due to ingestion of mustard oil contaminated with oil from Argemone mexicana, leading to edema and tenderness of the abdomen, upper and lower limbs. In this study, clinical profiles of patients presented with epidemic dropsy in north India are described. Methods: This was a prospective study of patients presented with epidemic dropsy to the emergency department of Nehru Hospital, during the period from March 2004 to December 2011. Inclusion criteria were patients presenting with tender bilateral pitting leg edema and dermal telangiectasia. Clinical and laboratory data of patients were entered into case record forms at the time of presentation until discharge from the hospital. Results: Leg edema was the principal symptom in our series, and was in concurrence with current literature. Erythema has only been reported in 35-82% of published series, though it was present in all of our patients. Similarly, features such as diarrhea, hepatomegaly and anemia were more frequent in our cases compared to the literature. Furthermore, pancytopenia which was documented on peripheral blood counts in 54% of our cases has never been reported before. Conclusion: Epidemic dropsy should be considered in patients presenting with progressive erythema, edema, and tenderness of the limbs who had a history of consumption of mustard oil and confirmation of Argemone oil contamination according to laboratory tests. More »»

2013

Journal Article

Dr. Madhu Mohan N., Chand, D. K., and Athilakshmi, J., “Selective detection of cysteine/cystine using silver nanoparticles”, 2013.

2012

Journal Article

V. Kumar, Pandey, N., Dr. Madhu Mohan N., and Singh, R. P., “Antibacterial & antioxidant activity of different extract of Moringa oleifera leaves–an in-vitro study”, International Journal of Pharmaceutical Sciences Review and Research, vol. 12, pp. 89–94, 2012.

2012

Journal Article

K. Raghubabu, Dr. Madhu Mohan N., Kalyanaramu, B., Ramadas, C., and Narayanarao, M., “Efficient and viable synthesis development for Tiaprofenic Acid in pharmaceutical industries”, Research Journal of Pharmaceutical Dosage Forms and Technology, vol. 4, pp. 318–319, 2012.[Abstract]


An industrially efficient method was developed to synthesize of tiaprofenic acid (5-benzoyl-alpha-methyl-2-thiopheneacetic acid) (1) which is a very important pharmaceutical compound having anti-inflammatory and analgesic activity. Sodium salt of propionitrile is reacted with 5-benzoyl-2bromothiophene (4) to yield nitrile crude (5) and further hydrolysis to give tiaprofenic acid (5-benzoyl-alpha-methyl-2-thiopheneacetic acid) (1). More »»

2012

Journal Article

K. Raghubabu, Dr. Madhu Mohan N., Kalyanaramu, B., Rao, M. N., and Ramdas, C., “Simple and Economical Visible Spectrophotometric Methods Development for Determination of Tiaprofenic Acid From its Solid Dosage Forms Based on Ion Association Complex Formation”, Tablet, vol. 1, pp. 197–46, 2012.[Abstract]


Two simple and sensitive extractive visible spectrophotometric methods (M1 and M2) for the determination of tiaprofenic acid in pure and dosage forms based on the formation of colored chloroform soluble ion-association associates under specified experimental conditions are described. Two basic dyes namely methylene blue (MB, method M1) and safranin-O (SAF-O, method M2) are utilized. The extracts of the ion-associates exhibit absorption maxima at 650nm and 520nm for methods M1 and M2 respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 8-24 µg/ml for method M1 and 8-40 µg/ml for method M2.The proposed methods are applied to commercial available tablets and the results are statistically compared with those obtained by the UV reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the tiaprofenic acid in the presence of other ingredients that are usually present in dosage forms. These methods offer the advantages of rapidity, simplicity and sensitivity and normal cost and can be easily applied to resource-poor settings without the need for expensive instrumentation and reagents. More »»

2011

Journal Article

Dr. Madhu Mohan N., Kumar, V. J., and Sankaran, P., “Linearizing Dual-Slope Digital Converter Suitable for a Thermistor”, Instrumentation and Measurement, IEEE Transactions on, vol. 60, pp. 1515-1521, 2011.[Abstract]


To measure temperature using a thermistor as the sensing element, linearization to compensate for the inverse exponential nature of the resistance-temperature characteristic of the thermistor is required. A linearizing dual-slope digital converter (LDSDC) that accepts a thermistor sensor as input and provides a digital output that is directly proportional to the temperature being sensed is presented here. A logarithmic amplifier at the input of the LDSDC compensates for the exponential characteristics. The conversion logic of the underlying dual-slope converter is suitably modified to implement the required inversion and offset correction and thus obtain linearization over a wide range of input temperature. The efficacy of the proposed LDSDC is established through simulation studies and its practicality demonstrated with experimental results obtained on a prototype unit built and tested. Analysis of the proffered method to identify possible sources of errors is also presented. More »»

2011

Journal Article

R. P Devi, Dr. Madhu Mohan N., V Kumar, P., and A Rao, N., “C-Means with Fuzzy Local Information”, Data Mining and Knowledge Engineering, vol. 3, pp. 952–960, 2011.[Abstract]


This paper presents a variation of Fuzzy c-Means(FCM )algorithm that provides image clustering .The proposed algorithm incorporates the local spatial information and gray level information in a novel fuzzy way.The new algorithm is called C-Means with Fuzzy Local Information (CMFLI). CMFLI can overcome the disadvantages of known fuzzy c-means algorithm and at the same time enhances the clustering performance.The major characteristic of CMFLI is the use of fuzzy local information(both spatial and gray level)similarity measure, aiming to guarantee noise insensitiveness and image detail preservation .Furthermore, the proposed algorithm is fully free of empirically adjusted parameters (a, λg , λs etc.) incorporated into all other fuzzy c-means algorithms proposed in the literature.Experiments performed on synthetic and real world images show that CMFLI algorithm is efficient,providing robustness to noisy images. More »»

2010

Journal Article

Dr. Madhu Mohan N., George, B., and Kumar, V. J., “A Novel Dual-Slope Resistance-to-Digital Converter”, Instrumentation and Measurement, IEEE Transactions on, vol. 59, pp. 1013-1018, 2010.[Abstract]


A dual-slope resistance-to-digital (DSRDC) converter that accepts the resistance of a single-element resistive-type sensor as input and provides a direct digital output proportional to the parameter being sensed by the resistive-type sensor is presented in this paper. A high level of linearity and accuracy is achieved since the output of the DSRDC is dictated only by the magnitudes of a pair of dc reference voltages and the transformation constant of the sensor. Sensitivity analysis shows that the effect of circuit parameter variations on the output is minimal. Simulation studies and test results obtained on a prototype establish the efficacy of the proposed scheme. More »»

2009

Journal Article

Dr. Madhu Mohan N., George, B., and Kumar, V. J., “Analysis of a Sigma #x2013;Delta Resistance-to-Digital Converter for Differential Resistive Sensors”, IEEE Transactions on Instrumentation and Measurement, vol. 58, pp. 1617-1622, 2009.[Abstract]


A direct resistance-to-digital converter (RDC) that is suitable for differential resistive sensors is proposed and analyzed in this paper. The RDC presented here provides a digital output that is linearly proportional to the parameter being sensed by a differential resistive sensor possessing either linear or inverse characteristics. The RDC employs the sigma-delta analog-to-digital conversion (Sigma-Delta ADC) principle and, hence, possesses all the advantages and limitations of such an ADC. Analysis shows that the proposed RDC has negligible sensitivity to variations in circuit parameters. Experimental results on a prototype built and tested gave a worst-case error < 0.15%, establishing the efficacy of the proffered RDC. More »»

2009

Journal Article

Dr. Madhu Mohan N., Shet, A. Ravikant, and Kedarnath, S., “Summaries of foreign technical paper: Digital converter for differential capacitive sensors”, JEMIC technical report, vol. 44, pp. 63-67, 2009.

2008

Journal Article

Dr. Madhu Mohan N., Shet, A. R., Kedarnath, S., and Kumar, V. J., “Digital Converter for Differential Capacitive Sensors”, IEEE Transactions on Instrumentation and Measurement, vol. 57, pp. 2576-2581, 2008.[Abstract]


A digital converter that directly translates variations in the capacitances of a differential-type capacitive sensor to a proportional digital value is described in this paper. A conventional dual-slope, analog-to-digital converter is suitably modified to obtain direct capacitance-to-digital conversion (CDC). Analysis of the proposed technique indicates that the effects of nonidealities and variations in circuit parameters on the performance of the CDC is either in the form of a gain error and/or an offset, both of which can be easily compensated. Simulation studies and experimental results obtained from a prototype built and tested prove the efficacy of the proposed scheme. More »»

2008

Journal Article

B. George, Dr. Madhu Mohan N., and Kumar, V. J., “A Linear Variable Differential Capacitive Transducer for Sensing Planar Angles”, Instrumentation and Measurement, IEEE Transactions on, vol. 57, pp. 736-742, 2008.[Abstract]


A linear variable differential capacitive transducer for the measurement of planar angles (from 0deg to 360deg) is presented in this paper. The sensor part of the transducer is made of parallel plates of standard and easy-to-fabricate shapes, and the signal-conditioning electronics are realized, employing a couple of simple relaxation oscillators. The output of the transducer is only dictated by a pair of dc reference voltages, and hence, high accuracy and linearity over the entire range (from 0deg to 360deg) are easily obtained by the use of precision dc reference voltages. Detailed analysis indicates that the sensitivity of the transducer is minimal for variations in different parameters. Experimental results obtained on a prototype transducer that has been built and tested establish the efficacy of the proposed transducer. The worst-case error of the prototype transducer is found to be less than 0.1%. More »»

2008

Journal Article

V. R. Rivera, Janice, G., Dr. Madhu Mohan N., and Poli, A. A., “Optimization of a functional paramagnetic bead-based electrochemiluminescence assay for botulinum toxins A and B”, Toxicon, vol. 51, Supplement, p. 53 -, 2008.[Abstract]


We used a paramagnetic bead format to develop a rapid throughput electrochemiluminescence (ECL) assay for botulinum toxins A and B (BoNT A and B). The assay took advantage of the toxins’ endoproteolytic activity by incubating custom-made ruthenium/biotin-labeled substrates with the neurotoxin and estimating the extent of signal reduction after cleavage of the amino acid terminus of the substrates. The neurotoxin's specific requirements for substrate length and amino acid sequence made the assay specific for these particular serotypes (A, B). Magnetic beads were added as solid support and captured the reaction product. The optimal pH for the reaction was 7.0 for both A and B substrates. A concentration of 50 mM \{HEPES\} was optimal for substrate cleavage, while concentrations above 80 mM resulted in a significant reduction in cleavage. Adding bovine serum albumin (BSA) (0.25–1.0 mg/ml) to the assay buffer increased cleavage rate. As expected, the activity of the enzyme required the addition of ZnCl, with 0.25–0.5 mM giving the best cleavage while concentrations over 1 mM resulted in decreased hydrolysis. Adding \{EDTA\} completely inhibited the reaction, confirming the requirement of Zn2+ for enzymatic activity. A significant decrease in substrate cleavage was observed at a temperature of 100 °C for both substrates but minor differences in cleavage occurred between 250 and 370 °C. The reaction time course showed increased cleavage of substrate with increased incubation time. The described assay offers considerable potential for both the detection and confirmation of BoNT A and B. The \{ECL\} assay offers a new alternative for the determination of the enzymatic activity of these toxins. The stable non-isotopic nature of the Ru label allows liquid-phase reagent convenience. The enhanced sensitivity in combination with adjustable incubation times means fast result turnaround. The rapid throughput nature of the assay could be used in the search for novel therapies against intoxication and provide a platform that could be expanded towards analytes with similar activities. More »»

2008

Journal Article

Dr. Madhu Mohan N., M. Reddy, R., Veeraiaha, N., and Jayasankar, C. K., “Spectroscopic and dielectric studies on MnO doped PbO–Nb2O5–P2O5 glass system”, Journal of Alloys and Compounds, vol. 458, no. 1, pp. 66-76, 2008.[Abstract]


PbO–Nb2O5–P2O5 glasses containing different concentrations of MnO ranging from 0 to 2.5 mol% were prepared. A number of studies viz., differential thermal analysis, infrared, optical absorption, luminescence, Raman and ESR spectra, magnetic susceptibility and dielectric properties (constant ɛ′, loss tan δ, ac conductivity σac over a range of frequency and temperature) of these glasses have been carried out. The results have been analyzed in the light of different oxidation states of manganese ions. The analysis indicates that when the concentration of MnO is around 1.0 mol%, manganese ions mostly exist in Mn2+ state, occupy network forming positions with MnO4 structural units and increase the rigidity of the glass network. When MnO is present in higher concentrations, these ions seem to exist mostly in Mn3+ state and occupy modifying positions. More »»

2007

Journal Article

V. J. Kumar and Dr. Madhu Mohan N., “Novel signal conditioning circuit for push-pull type capacitive transducers”, 2007.[Abstract]


A novel signal conditioning circuit suitable for push-pull type capacitive transducers is proposed. The circuit developed is capable of providing a linear output over a wide range of values of the physical quantity being measured even when the transducer output has an inverse relationship with the measurand. The push-pull type capacitive transducer becomes an integral part of a relaxation oscillator, the duty cycle ratio of the output of which becomes proportional to the measurand. The various sources of error in the circuit are analyzed More »»

2005

Journal Article

V. J. Kumar and Dr. Madhu Mohan N., “A novel signal conditioning circuit for push-pull-type resistive transducers”, 2005.

2002

Journal Article

Dr. Madhu Mohan N., “Novel Signal Conditioning Circuit for Push Pull Type Transducer”, Master of Science in Electrical Engineering, Indian Institute of Technology, Madras, 2002.

1992

Journal Article

S. M Rao, Chatterjee, R. K., and Dr. Madhu Mohan N., “Free iron oxides in soils of alfisolvertisol toposequence.”, Journal of the Indian Society of Soil Science (India), 1992.

1992

Journal Article

S. M Rao, Chatterjee, R. K., and Dr. Madhu Mohan N., “Amorphous ferri-aluminosilicates in associated soils of Alfisol-Vertisol toposequence”, Journal of the Indian Society of Soil Science, vol. 40, pp. 603–605, 1992.

1990

Journal Article

S. Raman, Dr. Madhu Mohan N., Goswami, N. N., and , “Scanning electron microscopic studies on the structure of salt affected soils treated with various amendments.”, Journal of the Indian Society of Soil Science, vol. 38, pp. 709–712, 1990.[Abstract]


A scanning electron microscope was used to study the effects of different amendments such as farm yard manure (FYM), pyrites and gypsum on the structure of two salt affected soils from Delhi and South Gujarat. Results indicate that gypsum was more effective in improving soil physical conditions than either pyrites or FYM. More »»

1985

Journal Article

Dr. Madhu Mohan N. and Sharma, J. P., “A Mote on the Occurrence of Petrocalcic (Cam) Horizon in Bellary, Karnataka”, Journal of the Indian Society of Soil Science, vol. 33, pp. 942–944, 1985.

1985

Journal Article

Y. S. Rao, Dr. Madhu Mohan N., and Rao, A. E., “Scanning Electron Microscopy Studies of Some Soils in Cuddapah Basin”, Journal of the Indian Society of Soil Science, vol. 33, pp. 841–845, 1985.

1983

Journal Article

Dr. Madhu Mohan N. and Rao, A. E. V., “Cation-exchange capacity of ferruginous soils of Goa and their importance in soil classification [India]. Short communication.”, Indian Journal of Agricultural Sciences, 1983.

1982

Journal Article

Dr. Madhu Mohan N. and Ghosh, S. K., “Occurrence of talc in highly weathered Plinthudult and Tropudalf soils of Goa [India]”, Science and Culture (India), 1982.

1982

Journal Article

D. K. Murthy, Rao, A. E. Vasudeva, and Dr. Madhu Mohan N., “Development of Inceptisols and Alfisols from granite gneiss rocks of Karnataka”, Indian journal of agricultural sciences, 1982.

1982

Journal Article

Y. S. Rao, Rao, A. E. V., and Dr. Madhu Mohan N., “Relationship of geomorphology to soil units in Cuddapah basin, Andhra Pradesh [India].”, Andhra Agricultural Journal, 1982.

1981

Journal Article

Dr. Madhu Mohan N. and Rao, A. E. Vasudeva, “Morphogenesis and classification of ferruginous soils of Goa. II. Physico-chemical properties and mineralogy of the Epi and Endopedons of Goa”, Mysore journal of agricultural sciences, 1981.

1980

Journal Article

Dr. Madhu Mohan N. and Rao, A. E. V., “Morphology genesis and classification of ferruginous soils. I. Geology, geomorphology and soils of Goa”, Mysore journal of agricultural sciences, 1980.

1978

Journal Article

R. K. Chatterjee and Dr. Madhu Mohan N., “Mineralogy of some tropical soils occurring in a sequence of varying drainage”, Journal of Nuclear Agriculture and Biology (India), 1978.

1972

Journal Article

S. V. G. Rajan, Murthy, R. S., Kalbande, A. R., and Dr. Madhu Mohan N., “Need for fertilizer and crop development programme in some dry land tracts of Mysore State”, Food farming and agriculture, 1972.

1970

Journal Article

Dr. Madhu Mohan N. and Chen, R., “Numerical curve fitting for calculating glow parameters”, Journal of Physics D: Applied Physics, vol. 3, no. 2, p. 243, 1970.[Abstract]


Numerical curve fitting of glow peaks, using a computer, is shown to be more objective and accurate than the existing graphical curve fitting method in evaluating trap activation energies. Besides using the numerical curve fitting method for glow peaks of first-order kinetics, the method is extended to the case of second-order thermoluminescence or thermally stimulated current peaks. The method was checked both for numerically generated peaks and experimental thermoluminescence curves of NaCl and ZnS: Er3+ samples. The results are in good agreement with the given values of activation energies in the former case and values calculated by other means in the latter. More »»

1968

Journal Article

S. V. G. Rajan, Murthy, R. S., LANDEY, R. J., and Dr. Madhu Mohan N., “MORPHOLOGY AND GENESIS OF AN INTERESTING SOIL ASSOCIATION IN GHATAPRABHA WATERSHED IN MUDHOL TALUK OF BIJAPUR DISTRICT, MYSORE”, INDIAN JOURNAL OF AGRICULTURAL SCIENCES, vol. 38, p. 992, 1968.

0

Journal Article

M. C. Rao, Ravindranadh, K., Kasturi, A., Dr. Madhu Mohan N., M Raju, D., Raju, G., and C Reddy, N. Kumar, “Microstructural Features of Mn2+ Doped SnO2Thin Films”.

0

Journal Article

K. Raghubabu, Dr. Madhu Mohan N., KalyanaRamu, B., and Ramdas, C., “ASSAY OF RACECADOTRIL IN COMMERCIAL FORMULATIONS BY VISIBLE SPECTROPHOTOMETRY”.

Publication Type: Book Chapter

Year of Publication Publication Type Title

2014

Book Chapter

H. Harini, Krithika, L. S., Shalini, M., Swaminathan, S., and Dr. Madhu Mohan N., “Design and Implementation of a Calibration - Free Pulse Oximeter”, in The 15th International Conference on Biomedical Engineering: ICBME 2013, 4th to 7th December 2013, Singapore, J. Goh Cham: Springer International Publishing, 2014, pp. 100–103.[Abstract]


Oxygen saturation in human beings is measured as the ratio of the amount of oxygen carried by hemoglobin to the maximum amount it could carry. A pulse oximeter is a device which measures this saturated oxygen content using the technique of photoplethysmography. Generally, the device consists of two LEDs (Red and IR) as light sources, and a photo diode as the detector. Depending on the intensity of light transmitted or reflected to the detector, oxygen saturation is computed. Commercially available pulse oximeters require calibration, since the device is dependent on sensor and patient-dependent parameters like skin color and thickness of the digit. This is normally done by acquiring data from volunteers, after which the necessary coefficients are extracted, for computing the saturated oxygen content. Such a calibration technique is dependent on the sample population, and hence is undesirable. The work presented here, makes use of a calibration-free algorithm published earlier, incorporating it into a micro-controller, leading to a compact, power-efficient, pulse oximeter. Moreover, present day pulse oximeters do not give access to the raw PPG data, which could be used for extracting important cardiovascular parameters. The preliminary design presented here provides a serial port interface in order to acquire and communicate the PPG signal to a PC, for further offline analysis. More »»

Publication Type: Conference Proceedings

Year of Publication Publication Type Title

2010

Conference Proceedings

Dr. Madhu Mohan N., G., V., M., V., P., S., and J., K. V., “Linearizing Digital Converter suitable for Thermistors”, IEEE International Instrumentation and Measurement Technology Conference (I2MTC). Austin, Texas, pp. 131-135, 2010.

2006

Conference Proceedings

Dr. Madhu Mohan N., R., S. A., and J., K. V., “Digital Converter for Differential Capacitive Transducers”, 23rd IEEE Instrumentation and Measurement Technology Conference (IMTC). Sorrento, Italy, pp. 772 - 775, 2006.

Publication Type: Thesis

Year of Publication Publication Type Title

2005

Thesis

S. Panday and Dr. Madhu Mohan N., “Design of agglomerated fluxes and their effect on weld metal composition and weldability in submerged arc welding”, INDIAN INSTITUTE OF TECHNOLOGY DELHI, 2005.

207
PROGRAMS
OFFERED
5
AMRITA
CAMPUSES
15
CONSTITUENT
SCHOOLS
A
GRADE BY
NAAC, MHRD
9th
RANK(INDIA):
NIRF 2017
150+
INTERNATIONAL
PARTNERS