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Kanagaraj N. 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3
The design and performance study of a variable fractional factor combined adaptive neuro-fuzzy inference system (VFANFIS) based maximum power point tracking (MPPT) technique for the thermoelectric generator (TEG) is presented. In this proposed MPPT technique, the fractional factor is used in such a way to achieve the variable tracking step size based on the operating point of the TEG in the power versus voltage (P–V) curve. The larger tracking step size move the TEG system operating point quickly towards the maximum power point (MPP), suppose the TEG operating point reaches near to MPP then the tracking step size becomes smaller to maintain stable output without any oscillation. In the proposed algorithm, the fractional factor value which is determined based on the change in voltage of the TEG is used expand or contract the input domain range of the ANFIS by which the variable tracking step size is achieved. The energy effi ciency of the TEG can be improved by attaining the MPP quickly and maintaining steady-state output around the MPP. The eff ectiveness of the VFANFIS-based MPPT technique is demonstrated with MATLAB simulation study under diff erent thermal and electrical operating condition. The study results are confi rmed that the proposed MPP tracker performs better to extract the maximum power from the TEG by achieving the MPP quickly and accurately when compared to the conventional incremental conduction (INC) based MPPT technique.
Insights into Combustion and Thermal Decomposition Behaviour of Electric Solid Propellants
Kanagaraj Gnanaprakash,Jai-ick Yoh 한국추진공학회 2021 Journal of Propulsion and Energy Vol.2 No.1
Recently, there is a growing interest in the development of electric solid propellants (ESPs) because they offer multiple start/stop operations and variable combustion rates at different electrical power. However, the understanding of complex reaction mechanisms involved in decomposition/combustion of these ESPs is still limited. The present study attempts to obtain insights into the thermal decomposition and combustion behaviour of ESPs based on lithium perchlorate (LP) oxidizer and poly vinyl alcohol (PVA) binder, and to further investigate the influence of tungsten (W) at 15% as a metal additive. Different parameters such as heat of reaction, mass loss, and combustion rates are obtained for metallized ESP-M15 and compared with the non-metallized baseline ESP. The heat release and mass loss from the overall decomposition reaction of baseline ESP are obtained as 3729 J/g and 51%, respectively. Addition of W decreases this net heat release by 43% and mass loss by 29% for ESP-M15, when compared to the baseline case. Combustion rates of both ESPs increase considerably with the applied initial voltage in the range of 100-500 V. Furthermore, inclusion of W in ESPs enhances their combustion rates by 4.6 times at 100 V and by 1.3 times at 500 V. This suggests that substantial oxidation of W at actual burning conditions improves the combustion rates of ESPs, whereas such process may not be significant at low temperatures of 30-600 °C in thermal experiments, thus reducing the heat release of metallized formulation relative to the baseline propellant.
Kanagaraj, Rajalakshmi,Nam, Yun-Sik,Pai, Sung Jin,Han, Sang Soo,Lee, Kang-Bong Elsevier 2017 Sensors and actuators. B Chemical Vol.251 No.-
<P><B>Abstract</B></P> <P>Gold nanoparticles (AuNPs) of various sizes were synthesized by modifying the citrate concentration; 45nm AuNPs were found to respond to Cr<SUP>6+</SUP> ions selectively. Label-free AuNPs, 45nm, showed localized surface plasmon resonance bands at 530nm, which decreased linearly upon addition of Cr<SUP>6+</SUP>. The addition of Cr<SUP>6+</SUP> also resulted in the appearance of a new band at 750nm, along with a visible color change in the solution from wine red to violet. The decrease in absorbance and color change were due to AuNP aggregation upon coordination of Cr<SUP>6+</SUP>. The detection limit for Cr<SUP>6+</SUP> was 0.4nM, and excellent selectivity was observed in the presence of other metal ions and anions. The binding site and sensing mechanism for Cr<SUP>6+</SUP> and label-free AuNPs were characterized by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. This method was applied to tap, pond, and waste water samples, and validated using inductively coupled plasma-optical emission spectrometry, illustrating the utility of the sensitive, selective, and simple AuNP sensor in the detection of Cr<SUP>6+</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Color change is induced by size-specific Au nanoparticles aggregation in the presence of Cr<SUP>6+</SUP> ions. </LI> <LI> A newly developed assay method uses 45nm label-free Au nanoparticles for detection of Cr<SUP>6+</SUP>ions. </LI> <LI> The sensor exhibits excellent selectivity for Cr<SUP>6+</SUP>ions over other metal cations and anions. </LI> <LI> The present assay method can detect a Cr<SUP>6+</SUP>ionic concentration of ∼ 0.4nM within 70min. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Manju</P> <P>[DISPLAY OMISSION]</P>
Green Electroluminescence from Charged Phenothiazine Derivative
Shanmugasundaram, Kanagaraj,Subeesh, Madayanad Suresh,Sunesh, Chozhidakath Damodharan,Chitumalla, Ramesh Kumar,Jang, Joonkyung,Choe, Youngson American Chemical Society 2016 The Journal of Physical Chemistry Part C Vol.120 No.36
<P>A novel charged green-emitting organic small molecule, PPP, was synthesized and characterized by thermal, photophysical, electrochemical, and electroluminescence investigations. The theoretical properties of PPP were confirmed by means of computational studies. PPP exhibits a good thermal decomposition temperature of 355 degrees C. The compound PPP shows positive solvatochromism upon increasing the solvent polarity due to the more polarized excited state arising from the intramolecular charge transfer in the excited state. Solid-state emission of PPP was slightly red shifted compared to that of its solution emission spectrum, showing the reduced intermolecular interaction in the solid state. Solution-processed LEC devices were fabricated using PPP as a neat light-emitting layer. The fabricated single-component light-emitting electrochemical cell devices exhibited green electroluminescence centered at 530 nm with the CIE coordinates of (0.32, 0.58). Electroluminescent devices operated at very low turn-on voltages reveal a maximum luminance of 499 cd/m(2). These promising results are highly desirable for the development of low-cost lighting devices.</P>
Rajalakshmi, Kanagaraj,Nam, Yun-Sik,Selvaraj, Muthusamy,Lee, Yeonhee,Lee, Kang-Bong Elsevier 2018 Sensors and actuators. B Chemical Vol.259 No.-
<P><B>Abstract</B></P> <P>A boronate group integrated on a triphenylimidazoleoxadiazolephenyl (TPIOP) moiety exhibited unusual sensing and detection abilities towards citrate. TPIOP boronate exhibited a bathochromic shift in its fluorescence emission upon interaction with citrate. Quantification of trace levels of citrate ions in the human body may aid in the diagnosis of prostate cancer and kidney malfunctions. Herein, a novel, metal-free sensing strategy for citrate was developed based on fluorimetric detection with TPIOP boronate. The fluorescence of TPIOP boronate increased linearly and was gradually red-shifted upon addition of citrate. The enhanced emission intensity was attributed to aggregation induced emission. The vacant ‘p’ orbital of boron in TPIOP boronate acts as a Lewis acid, and accepts electrons from citrate, which is a Lewis base. Upon binding, the hybridization geometry of boron changes from sp<SUP>2</SUP> trigonal planar to sp<SUP>3</SUP> tetrahedral. The TPIOP boronate-citrate aggregates increase the polarity of TPIOP-boronate, which caused the red shift in the fluorescence. Citrate could be detected visually using a UV lamp, as the probe changed from blue to green upon interaction with the analyte. The developed probe was applied for the visualization of endogenous citrate in PC3 live cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel boronate derivative was designed and synthesized for use as a metal-free citrate sensor. </LI> <LI> The sensor changes color from blue to green in the presence of citrate. </LI> <LI> Sensor showed 500-fold selectivity over other carboxylates, and the LOD was 10 nM. </LI> <LI> This probe showed low cytotoxicity and can be utilized for the detection of citrate in live PC3 cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>