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In this paper, we present a novel approach to achieve finite-time synchronization (FTS) in a certain class of fractional-order complex-valued neural networks (CVNNs) containing reaction-diffusion terms. The proposed method uses intermittent control and provides a theoretical analysis to establish criteria for achieving FTS. This is achieved through new Lyapunov functions based on the proposed system, deriving inequalities in the complex domain. To realize FTS, the study designs complex-valued intermittent controllers for the targeted CVNNs relying solely on the information obtained from the controlled nodes. Moreover, an adaptive controller is introduced to effectively regulate the control gain, and the FTS of CVNNs is analyzed. The effectiveness of the proposed control strategies and derived results is demonstrated by numerical examples. [ABSTRACT FROM AUTHOR]

This article studies dissipativity analysis of fractional-order quaternion-valued neural networks (FOQVNNs) with time delays. Two specific activation functions are considered along with common bounded and activation functions of Lipschitz-kind. Since quaternion multiplication is not commutative, we must divide the model, which is evaluated by quaternion, into four elements that are real-valued elements. On the basis of the construction of novel Lyapunov functional, and applying fractional-calculus theory, new criteria for the test of the global dissipativity and exponential stability of FOQVNNs model are established. FOQVNNs have also been suggested to provide global dissipativity and exponential stability, whereas nonlinear complex activation functions are constrained by the usage of linear matrix inequality methods, which utilize quaternion matrices and positive quaternion definite matrices. Finally, the effectiveness and superiority of the proposed approach is validated through numerical examples. [ABSTRACT FROM AUTHOR]

In this research, we aim to construct an unique sliding mode control time-varying switching surface that allows us to accurately synchronize fractional-order permanent magnet synchronous generator (FOPMSG) system at any arbitrary pre-specified time. With regard to the suggest methodology, the top limit of the synchronization time is entirely independent and depends entirely on the design parameters for the switching surface and control system. The major goal of modeling nonlinear PMSG fractional-order control is to improve the convergence rate which, compared to integerorder systems, is effectively superior. Moreover, resilience against existing uncertainties and external disruptions is achieved by removing the reaching phase within the proposed synchronization method. Furthermore, the Lyapunov stability theory is based on enough circumstances, which assures synchronization with the FOPMSG system at the pre-specified time, through the construction of a Lyapunov functional and SMC with switching surface. Finally, numerical examples and simulations to compare SMC scenarios highlight the usefulness of theoretical conclusions. [ABSTRACT FROM AUTHOR]

In this article, a method to evaluate the dc-link capacitor rms current of a switched reluctance motor (SRM) drive under different operating conditions is presented. Square current reference in both hard and soft chopping modes of pulsewidth-modulated current control is considered. By approximating the current controller response and using a recently proposed flux linkage model, the switching-cycle-average phase voltage and current are evaluated over an electrical cycle. The phase voltage and current are further used to obtain the rms values of dc-link current and capacitor current. The proposed method is also used to determine the capacitor current for low-torque-ripple current reference and single-pulse operation. The analytical predictions pertaining to different control methods under different operating conditions are verified by simulation and experimental results obtained from a 4 kW, 1500 r/min, four-phase SRM drive. While the capacitor current is found to be maximum at the lowest operating speed with hard chopping, the maximum capacitor current is observed at an intermediate speed with soft chopping, both for a given magnitude of square wave current reference. The proposed method is useful to size the dc-link capacitor and evaluate its loss in an SRM drive. Furthermore, closed-form expressions for capacitor rms current are also derived, assuming perfect tracking of square wave current reference at low speeds. These expressions bring out the dependence of capacitor rms current on the machine characteristics. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) is one of the key causes of high death rate globally. We report the cardio protective effect of an Ayurvedic polyherbal formulation Partharishtam on isoproterenol induced myocardial infarction on albino rats. Administration of Isoproterenol to normal albino rat triggers MI evident from the significant changes in key biomolecules tested in blood serum and cardiac tissues. The cardio protective role of Partharishtam was compared with a standard medicine, Propranolol on some of the known identifying markers of MI such as, Troponin I and T, creatine phosphokinase serum (CPK-S), creatine phosphokinase myoglobulin isozyme fraction (CPK-MB) and oxidative enzymes like super oxide dismutase (SOD), reduced glutathione (GSH) and catalase. There was an appreciable decrease in the levels of Troponin 1 and T, CPK-S and CPK-MB after the treatment of Partharishtam on Isoproterenol induced MI rats. In vivo anti-oxidative enzyme studies also revealed the increase in the levels of SOD, GSH and catalase to near normalcy after the treatment of Partharishtam in MI rats, which is very much comparable to the commonly used drug Propranolol to treat MI patients. Histopathological analysis confirmed the cardio protective properties of Partharistham in rat model. We did not find any side effects or toxicity of Partharishtam when tested on the normal rats. Thus, polyherbal formulation Partharishtam could be considered as safe medicine for MI. [ABSTRACT FROM AUTHOR]

High-power insulated gate bipolar transistors (IGBTs) are widely used for wind power conversion and electric traction. Accurate estimation of IGBT junction temperature and active thermal control improve the reliability of power converters in such applications. Among the various available methods for junction temperature estimation, thermo-sensitive electrical parameter (TSEP) based estimation is simple, fast and amenable to real-time implementation. Evaluation of many TSEPs (e.g. forward voltage, threshold voltage, peak dv/dt , peak di/dt etc.) require measurement of multiple electrical quantities in the power circuit and/or in the gate-drive circuit. The measurement systems need to have high precision and/or high bandwidth as well. Moreover, the quantities in the power circuit require isolated measurement systems. This paper explores possible new TSEPs, that could be obtained through a single measurement of low-voltage quantity, namely, the gate-emitter voltage. Since the gate-emitter voltage varies primarily during turn-on and turn-off delay intervals, these switching intervals and their parameters are studied over a wide range of operating conditions. Since many practical converters are expected to operate at an ambient temperature as low as −35 °C, the experimental study is carried out over a wide temperature range from −35 °C to 125 °C. Further, to ensure wider applicability of the findings of the study, four IGBTs of different makes are considered for the experimental investigations. The experimental results bring out four different parameters pertaining to turn-on delay and another four parameters pertaining to turn-off delay, which are potential TSEPs. Of these eight TSEPs, five of them can be evaluated based on measurement of gate-emitter voltage only, and four of these have not been reported in the literature previously. In addition, the experimental data are useful for development of temperature-sensitive device models for simulation, performance assessment and design of gate-drive circuit for different temperatures, and for temperature-sensitive compensation of inverter dead-time effect. • Thermo-sensitive electrical parameter (TSEP) based IGBT junction temperature estimate • Four TSEPs pertaining to turn-on delay and four more pertaining to turn-off delay are reported. • Five of the eight reported TSEPs are obtained from measurement of gate-emitter voltage only. • Two sub-intervals of turn-on delay time and two sub-intervals of turn-off delay time are potential TSEPs. • Turn-on gate time constant, turn-off gate time constant and turn-off plateau voltage are potential TSEPs. [ABSTRACT FROM AUTHOR]

Solid-rotor switched reluctance machines (SRM), having the rotor machined from a single piece of metal, are one of the few viable options for motoring and/or generation under harsh operating conditions, including high speeds, high shaft temperature, and corrosive environment. Apart from double saliency and high degree of magnetic saturation as in any SRM, significant core losses due to high eddy currents, even under static conditions, make the characterization and modeling of solid-rotor SRM challenging. The objective of this article is to understand the magnetic characteristics of a solid-rotor SRM through extensive experimental studies and to develop a stator-side model for the machine which adequately captures its magnetic behavior. First, the flux-linkage characteristics of the solid-rotor SRM under test are measured over a wide range of excitation conditions and rotor positions. Applying a computationally efficient decomposition technique on each set of experimental data, the measured winding current is resolved into magnetizing and core-loss components to obtain a stator-side model of the machine. The proposed model is useful to predict the winding current and core-loss under different excitation conditions, which is necessary for simulation and performance prediction. The proposed method is more accurate than the existing methods, while being simple and fast to implement. [ABSTRACT FROM AUTHOR]

In this paper we investigate controller design problem for finite-time and fixed-time stabilization of fractional-order memristive complex-valued BAM neural networks (FMCVBAMNNs) with uncertain parameters and time-varying delays. By using the Lyapunov theory, differential inclusion theory, and fractional calculus theory, finite-time stabilization condition for fractional-order memristive complex-valued BAM neural networks and the upper bound of the settling time for stabilization are obtained. The nonlinear complex-valued activation functions are split into two (real and imaginary) components. Moreover, the settling time of fixed time stabilization, that does not depend upon the initial values, is merely calculated. A novel criterion for guaranteeing the fixed-time stabilization of FMCVBAMNNs is derived. Our control scheme achieves system stabilization within bounded time and has an advantage in convergence rate. Numerical simulations are furnished to demonstrate the effectiveness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

This article proposes a mathematical model for a switched reluctance (SR) generator feeding a dc link through a power electronic converter. SR machines are operated in single-pulse mode at close to and above base speed. The SR generator is modeled as a current source, controllable with dc-link voltage $V_{\text{dc}}$ , prime mover speed $\omega _m$ , and switching angles ($\alpha _{\text{on}}$ and $\alpha _{\text{off}}$) of the converter. This current source model is used to predict the dc-link dynamics for constant resistance, constant current, and constant power loads. This is further utilized to derive the voltage build-up condition for an SR generator. The generator model, dc-link dynamics and voltage build-up conditions are validated through simulations and experiments. [ABSTRACT FROM AUTHOR]

A position sensorless operation of a doubly-fed induction generator (DFIG) is desired from considerations of cost, maintenance, cabling, and reliability. This article proposes two stator flux based model reference adaptive observers (SF-MRAOs) for the estimation of the rotor speed and position in a stand-alone DFIG. The cross product of the reference and estimated stator flux linkage vectors is fed as controller input in the existing method, thereby, making the observer model nonlinear. The first proposed method, which is based on notch filtering, offers a performance comparable to that of the existing method while reducing the number of voltage and current sensors required. The second proposed method linearizes the error input to the controller, making the controller design straight forward, and also leading to superior performance than the existing methods. The linearized SF-MRAO is shown to work successfully with good dynamic performance in vector control of a stand-alone DFIG. This article also shows that the proposed linearized SF-MRAO can be employed for obtaining the rotor current angle in direct voltage control of a stand-alone DFIG. Simulation and experimental results are presented from a laboratory prototype of a 10-hp DFIG coupled to a squirrel-cage induction motor. The sensitivity of the performance of the proposed linearized SF-MRAO to variations in machine parameters is also studied theoretically and experimentally. [ABSTRACT FROM AUTHOR]

Depleting fossil fuels and concerns about global warming have forced a paradigm shift toward renewable energy resources in meeting our energy requirements. Wind energy utilization has been growing at a rapid rate fuelling research and development in high power wind turbines (WTs). To advance research and education in wind energy conversion systems, a controlled test bed is necessary that does not depend on wind availability. Majority of the existing WT emulation schemes employ a torque compensation loop to account for the inertia difference between the WT and motor used for emulation. However, the loop suffers from noise and instability issues. Also, the torque compensation term is sensitive to parameter estimates. This article proposes one degree of freedom (1-DOF) and 2-DOF control structures for WT emulation. It first illustrates the design and performance of 1-DOF control structure. It further proposes two controllers along with their prefilters in 2-DOF structure, which has superior performance than 1-DOF structure. The design of the controllers and prefilters is explained with the help of root locus. The performance of the WT emulator with the proposed control structures is demonstrated through simulations and experiments on a 7.5 kW doubly fed induction generator driven by a 5.5 kW squirrel cage induction motor, where the dynamics and steady-state operation of a WT–generator system are emulated. [ABSTRACT FROM AUTHOR]

Introduction: In the management of neurodegenerative and neuropsychiatric diseases, memory loss remains very challenging. Saraswatharishtam (SWRT) is an ayurvedic formulation prescribed for several neurological ailments like acute anxiety, partial memory loss, slurred speech, neuro-degenerative diseases like Parkinson's, Alzheimer's etc. Methods: Present study explores the possibilities of curative effects of SWRT on Scopolamine induced memory impairment and to compare the effects of commonly used drug Piracetam. Adult Wistar Swiss albino mice were used for this experiment and divided into five different groups for the treatments of the drugs in various combinations. The first group was vehicle treated control while the second group was treated with scopolamine to induce memory impairment. The third groups of animals were treated with Scopolamine where the mice were pretreated with standard neuro-protective drug Piracetam, while the fourth and fifth groups of animals were treated with scopolamine and the animals were pretreated with SWRT at the doses of 200 and 400 mg/kg respectively to compare with the effect of Piracetam. Scopolamine was administered on day eight, only for 45 minutes in all the cases (Group I- Group V). Several neurobehavioral parameters were examined to confirm the neuro-protective effects of SWRT. Results: Saraswatharishtam significantly reversed the memory loss in mice model as revealed from elevated plus maze, radial maze and rectangular maze experiments justifying its neuroprotective potential as observed in usually used synthetic Piracetam. SWRT was found to be nontoxic and very promising antioxidant recorded from acute and chronic toxicological studies. Conclusions: It is suggested that SWRT, could be used as safe and easily available Ayurveda medicine to treat neurological dysfunctions without any side effects. Further translational research is needed to explore its neuro-protective potential. [ABSTRACT FROM AUTHOR]

The accuracy of a power-hardware-in-loop (PHIL) simulation is influenced by factors such as dynamics of the power amplifier (PA) and discretization of the real-time simulated part of the system. An open-loop voltage-source inverter (VSI) without an output filter is demonstrated to be a good choice for power amplification in terms of cost, size, design effort, bandwidth, and accuracy when the load on the PA is significantly inductive. An open-loop-VSI-based PA is shown to be accurate in emulating a synchronous generator, including the fast transients in the excitation control system. The discretization effects of the real-time simulator are captured effectively by the discrete-time (DT) modeling approach proposed in this paper. The DT model is shown to replicate fast transients in the PHIL simulation better than the existing continuous-time-based model. Stability of the PHIL simulation of a benchmark circuit is analyzed using the proposed DT modeling approach. The stability analysis is validated through simulations and experiments. The stability limits derived based on the proposed analysis are capable of suggesting maximum and minimum values of certain circuit parameters, as required for stability. [ABSTRACT FROM AUTHOR]

Objective: The present study deals with the gas chromatography–mass spectrometry (GC–MS) analysis of an anti-obesity Ayurvedic medicine, Lohasava. Methods: Lohasava was bought from a standard Ayurvedic vendor at Chennai and subjected to GC–MS analysis by standard procedures. The medicinal roles of the biomolecules indicated in the GC–MS profile were screened for their various medicinal roles using Dr. Duke’s phytochemical and ethno-botanical data and other data. Results: The GC–MS profile of Lohasava indicated the presence of important biomolecules such as butanoic acid, 3-hydroxy-, ethyl ester, phenylethyl alcohol, ethyl hydrogen succinate, thymol, 4-hydroxy-2-methylacetophenone, hydrocinnamic acid, 2,6-dimethoxyphenyl-beta-phenylpropionate, bisphenol C, benzeneethanamine, 2,5-dimethoxy-alpha.,4-dimethyl-and piperine. Conclusions: It is concluded that Lohasava does have a scientific efficacy toward its claimed role as a medicine in Ayurveda. Further research is required for a better understanding of the medicinal roles of Lohasava. [ABSTRACT FROM AUTHOR]

Introduction: The present work deals with the gas chromatography (GC)–mass spectrometry (MS) analysis of Drakshadi Kashayam, which is used in the treatment of Panduroga (anemia), jaundice, and diseases caused due to imbalance in Pitta (bile) consistency. Methods: Drakshadi Kashayam was bought from a standard Ayurvedic vendor at Chennai and subjected to GC–MS analysis by standard procedures. The medicinal roles of the biomolecules indicated in the GC–MS profile were screened for their various medicinal roles using Dr. Duke’s phytochemical and ethnobotanical data and other data. Results: GC–MS profile of Drakshadi Kashayam indicated the presence of important biomolecules such as carbonic acid, pentyl phenyl ester, bisphenol C, histamine, N-benzoyl-2-cyano-, o-Methoxy-.alpha.-phenethylamine, benzenethanamine, 3,4-dimethoxy-.alpha.-methyl-, cis-Z-.alpha.-Bisabolene epoxide, and 1,3-Dimethoxy-5-(1-methyl-heptyl)-benzene which have medicinal roles supporting the efficacy of Drakshadi Kashayam as a liver tonic. Conclusions: It is concluded that Drakshadi Kashayam, which is an important Ayurvedic medicine, does contain some very important molecules showing its efficacy. Further research is required for a better understanding of the medicinal roles of this medicine. [ABSTRACT FROM AUTHOR]

Introduction: The present work deals with the gas chromatography–mass spectrometry (GC-MS) analysis of Kutajarishtam which is used in the treatment of diarrhea, dysentery, irritable bowel syndrome, Crohn’s disease, hemorrhoids, etc. Materials and Methods: Kutajarishtam was bought from a standard Ayurvedic vendor at Chennai and subjected to GC-MS analysis by standard procedures. The medicinal roles of the biomolecules indicated in the GC-MS profile were screened for their various medicinal roles using Dr. Duke’s Phytochemical and ethnobotanical data and other data. Results: GC-MS profile of Kutajarishtam indicated the presence of important biomolecules such aso-Acetyl-L-serine, 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, 2-Furanethanol., beta.-ethoxy-, Acetic acid, 1-(2-hydroxy-1-methyl-ethyl)-3-methoxymethoxy-2-methyl-propyl ester and Cyclohexan-1,4,5-triol-3-one-1-carboxylic acid which have medicinal roles which correlated well with that of Kutajarishtam. Conclusions: It is concluded that Kutajarishtam, which is an important Ayurvedic medicine, contains some very important molecules showing its efficacy. Further research is required for a better understanding of the medicinal roles of this medicine. [ABSTRACT FROM AUTHOR]

Induction motor drives operated with a low ratio of the switching frequency to the fundamental frequency (i.e., pulse number) are prone to have high magnitudes of low-order torque harmonics. This paper proposes a method to analytically evaluate the harmonic torque spectrum based on the pulsewidth-modulated voltage waveforms for low pulse number operation. The predicted torque harmonic spectra for different pulsewidth-modulated waveforms are validated through simulations and experiments. This paper also reports optimal switching angles to minimize the total rms value of torque harmonics of order 6, 12, 18 $,\dots,$ $6(N-1)$ , considering the number of switching angles per quarter ($N$) to be 4 and 5. Compared to sine triangle pulsewidth modulation and selective harmonic elimination pulsewidth modulation with the same pulse number, the proposed optimal switching angles significantly reduce the total rms value of all harmonic torques of order lower than $6N$. Extensive simulation and experimental results on a 3.7-kW induction motor drive are presented to demonstrate the superior performance of the proposed optimal pulsewidth modulation. [ABSTRACT FROM AUTHOR]

Inverter dead-time is known to make open-loop induction motor drives oscillatory, while operating at light-loads in particular. While dead-time compensation schemes exist, precise compensation of the same is often challenging as it involves factors such as device and driver delays and switching transition times, which are difficult to be quantified accurately. Hence, the effect of dead-time could be under or overcompensated. This paper presents a comprehensive analysis of the impact of such undercompensation and overcompensation on the stability of a 100-kW induction motor drive, along with experimental investigations of the same. The effects of undercompensation and overcompensation on the inverter output voltage are analyzed on a switching-cycle average basis. Further, small-signal models are proposed for an open-loop drive, when it is undercompensated and overcompensated. Stability analysis of the above motor drive is reported, which predicts oscillatory behavior with both under and overcompensation, over certain fundamental frequency ranges, respectively. Further, two different types of oscillatory behavior, characterized by different oscillating frequencies, are observed for the cases of under and overcompensation. The analyses are supported by simulations. Experimental investigations carried out also support the analyses and simulation results. [ABSTRACT FROM AUTHOR]

A novel constant current injection-based characterization scheme for the switched reluctance machine (SRM) is proposed here. Unlike conventional characterization methods where the rotor is locked at a fixed position, the current injection-based method maintains the phase current constant while the machine runs at constant speed. A novel current controller, required for the proposed constant current injection scheme, is also proposed in this paper. The predictive control-based current controller works without the machine model being available. The proposed current controller is validated experimentally and is then used to characterize a 4 kW, 1500 r/min 8/6 pole SRM. The characteristics obtained are found to be in good agreement with those obtained using conventional locked rotor tests. [ABSTRACT FROM AUTHOR]

Neutral-point-clamped (NPC) multilevel inverter fed high power drives operating at low switching frequency are prone to low-order torque pulsations. For a case of N switching angles per quarter, apart from maintaining the fundamental component, (N-1) voltage harmonics can be eliminated. Consequently, \fracN-12 or lower number of torque harmonics could be eliminated. This paper proposes an optimal pulse-width modulation (PWM), which minimizes the combined root mean square (RMS) value (\tau RMS ) of torque harmonics of order lower than $6N$ at any modulation index (M$) for an induction motor drive fed from an NPC three-level inverter. This paper considers cases of two, three, and four switching angles per quarter cycle of the pole voltage. Compared with synchronized sine-triangle PWM and selective harmonic elimination (SHE) PWM, the proposed PWM reduces the first (N-1$ ) torque harmonics (i.e., \tau _6 ) over a wide speed range. Simulation and experimental results are presented on a 3.7-kW open-loop constant volts-per-Hertz induction motor drive. [ABSTRACT FROM PUBLISHER]

The effect of inverter dead time on the inverter output voltage is well studied in the literature. This paper studies the effect of the dead time on the inverter input current. An expression for the switching-cycle-averaged inverter input current including the dead time effect is derived, which shows the dead time effect to primarily result in a reduction in the average value of the inverter dc input current. The effect of dead time on the input current is incorporated into the dc-link dynamic model of a diode-bridge-rectifier (DBR) fed voltage source inverter (VSI). A switching-cycle-average model of a DBR-VSI-fed induction motor is proposed, which considers the effect of dead time on both the ac output voltage and dc input current of the VSI. The proposed average model is used to study the light-load instability phenomenon in a 100-kW open-loop motor drive. The proposed model is shown to predict the region of oscillatory behavior (i.e., region exhibiting light-load instability) with better accuracy than existing average models. The proposed model also accurately predicts the dc-link voltage swing at such oscillatory operating points. While being comparable in accuracy in predicting the system dynamics, the proposed model is much more computationally efficient than the state-of-the-art switching model. The validity of the proposed average model is also confirmed by experimental measurements on a 100-kW induction motor drive. [ABSTRACT FROM AUTHOR]

Until recently, personality disorder research in India has been a largely neglected area. A small body of epidemiological research reveals lower prevalence rates for personality disorders in India than seen globally. The present study aims to examine personality disorders within the lens of family of origin and values, thereby providing a culturally relevant framework to understand this heterogeneous and complex clinical condition. The participants were recruited over a 2-year time period and comprised of 20 adults with personality disorders who, using a matched case-control design, were compared with 20 participants from the community. A total of three focus groups were conducted to develop themes for an in-depth interview that highlighted four context specific themes relevant to personality disorders (mood states that impact the self, significant life experiences, impact of family of origin and procreation, and value organization). The study revealed several key findings. Like previous studies, borderline and avoidant personality disorders were more common. Interestingly, participants were brought to the clinical setting in their late twenties. Internalized emotional reactions were predominant. The family acted as both a source of stress, abuse and support, with ties being maintained with extended family such as grandparents, siblings and spouse. Dissonance between individual values and existing pluralistic Indian cultural belief system was experienced. The findings highlight the requirement for expanding on cultural models of personality disorders in South Asian settings and integrating them into mainstream psychosocial assessment and interventions. [ABSTRACT FROM AUTHOR]

Pulses are one of the most important legume crops in India contributing significantly high quality protein. Among the legumes, black gram (Vigna mungo L. Hepper), is an important legume crop in our country belonging to the family leguminoceae. The low productivity in pulses may be due to the fact that they are normally grown in marginal lands with inadequate soil moisture and poor fertility status. To increase yield under these circumstances, integrated seed treatment is given as a presowing treatment. Hence, a study was attempted to find out the influence of integrated seed treatments on growth and yield parameters in black gram. The seeds of black gram cv VBN 4 were subjected to various seed treatments and treated seeds along with the control were evaluated for their seed quality, growth, gas exchange and yield parameters both in laboratory and field trials. The study revealed that seeds fortified with MgSO4 + polykote + carbendazim + dimethoate + bioinoculant (Pseudomononas fluorescens) + Rhizobium + Azophos + pelleting with DAP recorded higher seed yield and other parameters when compared to control. [ABSTRACT FROM AUTHOR]

The control of the engine exhaust noise by a particulate trap for a diesel engine is investigated. Adequate theoretical background about the sound waves and engine noise is provided with a brief discussion on the sources of engine noise, exhaust noise generation and the principle of suppression. The experimental work comprises of design and development of the particulate trap for the given engine to control the exhaust noise level. The noise level reduction is also studied using a muffler. The reduction in noise level using particulate trap and muffler is experimentally investigated and compared. [ABSTRACT FROM AUTHOR]

Pulse-width modulation (PWM) of a motor drive at a fixed switching frequency leads to harmonic currents in narrow bands around integral multiples of the switching frequency resulting in tonal frequency acoustic noise components, which are irritating to the human ear. Random variation of carrier frequency to spread the spectrum poses challenges in device loss calculation, thermal design, and closed-loop controller design. Random pulse positioning is not quite effective at high speeds of the drive, where the problem of acoustic noise is most pronounced. This paper proposes a simple variable-frequency PWM and evaluates the performance of the same experimentally on a 6-kW induction motor drive. The experimental results show that the acoustic noise is spread uniformly over a range of frequencies without introducing low-frequency current harmonics. Compared with fixed-frequency PWM, the dominant acoustic noise is reduced significantly over a wide range of speeds. The variable-frequency PWM is further shown to reduce line current total harmonic distortion at high speeds of the drive. The computational effort required by the variable-frequency PWM is only marginally higher than that required by fixed-frequency PWM. [ABSTRACT FROM PUBLISHER]

Current control of a switched reluctance motor (SRM) is challenging due to nonlinearity and double saliency of the machine. A linear proportional-integral (PI)-based current controller, which is popular in other electrical machines, cannot be directly applied, as this requires a linearized machine model. This paper examines different small-signal linearized models for an SRM and identifies the model best suited for the purpose of current controller design. This paper then utilizes this linearized model to propose a fixed proportional-integral (PI)-based current controller, the parameters of which can be selected directly from the machine parameters. This paper also proposes a simple method to evaluate back-electromotive force (EMF) for the purpose of disturbance rejection during current control. The performance of the proposed fixed-PI-based control with back-EMF compensation is better than that of delta modulation in terms of current ripple; it is comparable to that of variable-gain PI with back-EMF compensation in terms of current ripple and current reference tracking. While variable-gain PI requires knowledge of the entire flux-linkage characteristics and involves calculation of controller gains in every sampling interval, the proposed method requires only limited details of the motor characteristics and is much simpler to implement. [ABSTRACT FROM PUBLISHER]

The present investigations were carried out to study the influence of various seed hardening treatments on growth and yield parameters in black gram under drought condition. The black gram cv.VBN 3 was imposed with various seed hardening treatments (i.e.,) MnSO4 @ 100 ppm, ZnSO4 @ 100 ppm, Cobalt nitrate @ 1 %, Sodium molybdate @ 100 ppm, KCl @ 100 ppm, Pungam leaf extract @ 1 %, Prosopis leaf extract @ 1% and GA3 @ 40 ppm. The above treated seeds along with control were evaluated for their seed quality parameters, growth, gas exchange and yield parameters under laboratory and drought field condition. The study revealed that seeds hardened with prosopis leaf extract @1% recorded higher seed yield, yield attributing characters and many seed quality characters as compared to other treatments and control under drought condition. [ABSTRACT FROM AUTHOR]

A low-order harmonic pulsating torque is a major concern in high-power drives, high-speed drives, and motor drives operating in an overmodulation region. This paper attempts to minimize the low-order harmonic torques in induction motor drives, operated at a low pulse number (i.e., a low ratio of switching frequency to fundamental frequency), through a frequency- domain (FD) approach as well as a synchronous reference frame (SRF) based approach. This paper first investigates FD-based approximate elimination of harmonic torque as suggested by classical works. This is then extended into a procedure for minimization of low-order pulsating torque components in the FD, which is independent of machine parameters and mechanical load. Furthermore, an SRF-based optimal pulsewidth modulation (PWM) method is proposed to minimize the low-order harmonic torques, considering the motor parameters and load torque. The two optimal methods are evaluated and compared with sine-triangle (ST) PWM and selective harmonic elimination (SHE) PWM through simulations and experimental studies on a 3.7-kW induction motor drive. The SRF-based optimal PWM results in marginally better performance than the FD-based one. However, the selection of optimal switching angle for any modulation index $(M)$ takes much longer in case of SRF than in case of the FD-based approach. The FD-based optimal solutions can be used as good starting solutions and/or to reasonably restrict the search space for optimal solutions in the SRF-based approach. Both of the FD-based and SRF-based optimal PWM methods reduce the low-order pulsating torque significantly, compared to ST PWM and SHE PWM, as shown by the simulation and experimental results. [ABSTRACT FROM AUTHOR]

Constant-volts-per-hertz induction motor drives and vector-controlled induction motor drives utilize pulsewidth modulation (PWM) to control the voltage applied on the motor. The method of PWM influences the pulsations in the torque developed by the motor. A space-vector-based approach to PWM facilitates special switching sequences involving the division of active state time. This paper proposes a space-vector-based hybrid PWM technique, which is a combination of the conventional and special switching sequences. The proposed hybrid PWM technique results in a lower peak-to-peak torque ripple than conventional space vector PWM (CSVPWM) at high speeds of an induction motor drive. Furthermore, the magnitude of the dominant torque harmonic due to the proposed hybrid PWM is significantly lower than that due to CSVPWM at high speeds of the drive. Experimental results from a 3.75-kW sensorless vector-controlled induction motor drive under various load conditions are presented to support analytical and simulation results. [ABSTRACT FROM AUTHOR]

This paper investigates possible reduction of pulsating torque in open-loop and vector-controlled induction motor drives through deployment of certain advanced bus-clamping pulsewidth modulation (ABCPWM) method. Toward this goal, a simple and machine-independent method is proposed to analyze the torque harmonic spectrum of a voltage source inverter fed induction motor, operated with any real-time pulsewidth modulation (PWM) method. The analytically evaluated torque harmonic spectra, pertaining to conventional space vector PWM (CSVPWM), bus-clamping PWM (BCPWM), and ABCPWM, are validated through simulation and experimental results. Theoretical and experimental studies bring out the superiority of the ABCPWM in terms of torque harmonics over CSVPWM and BCPWM. The magnitude of the dominant torque harmonic with the ABCPWM scheme is shown to be significantly lower than that with CSVPWM, over a wide range of speed. The rms torque ripple (i.e., total rms value of all harmonic torques) is lower with ABCPWM than with BCPWM over the entire range of speed. [ABSTRACT FROM PUBLISHER]

The objective of this paper is to study the influence of inverter dead-time on steady as well as dynamic operation of an open-loop induction motor drive fed from a voltage source inverter (VSI). Towards this goal, this paper presents a systematic derivation of a dynamic model for an inverter-fed induction motor, incorporating the effect of inverter dead-time, in the synchronously revolving dq reference frame. Simulation results based on this dynamic model bring out the impact of inverter dead-time on both the transient response and steady-state operation of the motor drive. For the purpose of steady-state analysis, the dynamic model of the motor drive is used to derive a steady-state model, which is found to be non-linear. The steady-state model shows that the impact of dead-time can be seen as an additional resistance in the stator circuit, whose value depends on the stator current. Towards precise evaluation of this dead-time equivalent resistance, an analytical expression is proposed for the same in terms of inverter dead-time, switching frequency, modulation index and load impedance. The notion of dead-time equivalent resistance is shown to simplify the solution of the non-linear steady-state model. The analytically evaluated steady-state solutions are validated through numerical simulations and experiments. [ABSTRACT FROM AUTHOR]

This paper demonstrates light-load instability in a 100-kW open-loop induction motor drive on account of inverter deadtime. An improved small-signal model of an inverter-fed induction motor is proposed. This improved model is derived by linearizing the nonlinear dynamic equations of the motor, which include the inverter deadtime effect. Stability analysis is carried out on the 100-kW 415-V three-phase induction motor considering no load. The analysis brings out the region of instability of this motor drive on the voltage versus frequency (V-f) plane. This region of light-load instability is found to expand with increase in inverter deadtime. Subharmonic oscillations of significant amplitude are observed in the steady-state simulated and measured current waveforms, at numerous operating points in the unstable region predicted, confirming the validity of the stability analysis. Furthermore, simulation and experimental results demonstrate that the proposed model is more accurate than an existing small-signal model in predicting the region of instability. [ABSTRACT FROM AUTHOR]

Laboratory experiments were conducted to study the effect of different pre storage treatments and packaging materials on storability of Jatropha seeds. The treatments included halogen mixture @ 3g kg-1, Thiram @ 2g kg-1 and packed in three different containers viz., Aluminium container, Polythene bag and Cloth bag. The seeds were evaluated at monthly intervals upto ten months and observations on germination percent and vigour index were recorded in two varieties viz., Chidambaram local and Sirkali local. The results revealed that Jatropha seeds treated with halogen mixture and stored in aluminium container could be stored upto 7 months without loss in vigour and viability. [ABSTRACT FROM AUTHOR]

A Study was conducted at Department of Genetics and Plant Breeding, Faculty of Agriculture, Annamalai University Annamalai Nagar to standardize the dosage of flyash for seed pelleting in sesame with different concentrations ranging from 25 g to 300 g with 3 doses of gum as adhesive material. Based on the results, it was found that seed quality charecters increased along with increased dosage of flyash treatment in general and flyash treatment @ 250 g.kg-1 and with 10% or 5 % gum Arabica as adhesive material was identified as the best dose for seed pelleting in sesame. [ABSTRACT FROM AUTHOR]

The voltage ripple and power loss in the DC-capacitor of a voltage source inverter depend on the harmonic currents flowing through the capacitor. This paper presents a double Fourier series based analysis of the harmonic contents of the DC capacitor current in a three-level neutral-point clamped (NPC) inverter, modulated with sine-triangle pulse-width modulation (SPWM) or conventional space vector pulse-width modulation (CSVPWM) schemes. The analytical results are validated experimentally on a 3-kVA three-level inverter prototype. The capacitor current in an NPC inverter has a periodicity of 120°at the fundamental or modulation frequency. Hence, this current contains third-harmonic and triplen-frequency components, apart from switching frequency components. The harmonic components vary with modulation index and power factor for both PWM schemes. The third harmonic current decreases with increase in modulation index and also decreases with increase in power factor in case of both PWM methods. In general, the third harmonic content is higher with SPWM than with CSVPWM at a given operating condition. Also, power loss and voltage ripple in the DC capacitor are estimated for both the schemes using the current harmonic spectrum and equivalent series resistance (ESR) of the capacitor. [ABSTRACT FROM AUTHOR]

Background Antimicrobial resistance poses a significant threat to public health globally. We studied the prevalence of colonization with extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE), carbapenem-resistant Enterobacterales (CRE), and colistin-resistant Enterobacterales (Col-RE) in hospitals and the surrounding community in South India. Methods Adults from 2 hospitals and the catchment community who consented to provide stool specimens were enrolled. Stools were plated on CHROMagar selective for ESCrE, CRE, and Col-RE. Bacterial identification and antibiotic susceptibility testing were done using Vitek 2 Compact and disc diffusion testing. Colistin broth microdilution was performed for a subset of isolates. Prevalence estimates were calculated with 95% confidence intervals (CIs), and differences were compared across populations using the Pearson χ 2 or Fisher exact test. Results Between November 2020 and March 2022, 757 adults in the community and 556 hospitalized adults were enrolled. ESCrE colonization prevalence was 71.5% (95% CI, 68.1%–74.6%) in the community and 81.8% (95% CI, 78.4%–84.8%) in the hospital, whereas CRE colonization prevalence was 15.1% (95% CI, 12.7%–17.8%) in the community and 22.7% (95% CI, 19.4%–26.3%) in the hospital. Col-RE colonization prevalence was estimated to be 1.1% (95% CI,.5%–2.1%) in the community and 0.5% (95% CI,.2%–1.6%) in the hospital. ESCrE and CRE colonization in hospital participants was significantly higher compared with community participants (P <.001 for both). Conclusions High levels of colonization with antibiotic-resistant Enterobacterales were found in both community and hospital settings. This study highlights the importance of surveillance of colonization in these settings for understanding the burden of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Acute lymphoblastic leukaemia (ALL) presenting as peripheral blood hypereosinophilia is very rare and the incidence is <1%. The characteristic feature of patients with ALL and hypereosinophilia is the absence of blasts in peripheral blood, and this might lead to misdiagnosis of ALL. It is important for clinicians and pathologists to be aware of this uncommon initial presentation of ALL to avoid delay in diagnosis. We report a 37‑year‑old man who presented with fever and respiratory symptoms and was found to have hypereosinophilia in peripheral blood. His bone marrow and lymph node biopsies were diagnostic of ALL. [ABSTRACT FROM AUTHOR]

The present study was attempted to find out the influence of various seed hardening cum foliar spray treatments on growth and yield parameters in black gram under dry land condition. The seeds of black gram cv VBN 3 were imposed with hardening treatment with prosopis leaf extract @ 1%, and then they were again given with foliar spray treatments. The above treated seeds along with control were evaluated for their growth, physiological and yield parameters under field condition. The study revealed that, 1%, Prosopis leaf extract hardened seeds along with foliar spray of salicylic acid @ 100 ppm recorded the higher seed yield and other parameters when compared to other treatments and control. [ABSTRACT FROM AUTHOR]

The DC capacitor is an important component in a voltage source inverter. The RMS current flowing through the capacitor determines the capacitor size and losses. The losses, in turn, influence the capacitor life. This paper proposes a space vector based modulation strategy for reducing the capacitor RMS current in a three-level diode-clamped inverter. An analytical closed-form expression is derived for the DC capacitor RMS current with the proposed PWM strategy. The analytical expression is validated through simulations and also experimentally. Theoretical and experimental results are presented, comparing the proposed strategy with conventional space vector PWM (CSVPWM). It is shown that the proposed strategy reduces the capacitor RMS current significantly at high modulation indices and high power factors. [ABSTRACT FROM AUTHOR]

Field experiments were conducted to study the effect of fly ash seed pelleting in rice under aerobic agriculture which can be recommended for better crop growth and establishment. The study was conducted with three concentrations viz., 200, 250 and 300g per kg of seed. Observations on growth and yield parameters viz., plant height, dry matter production, leaf area, root weight, number of productive tillers/plant, number of grains/panicle, 1000 grain weight, and single plant yield were recorded. Gas exchange parameters viz., net photosynthetic rate, leaf transpiration rate, stomatal conductance and intercellular CO2 concentration were also recorded. The experimental results revealed that aerobic rice seeds treated with fly ash @ 250 g kg-1 performed better due to increased growth, gas exchange parameters and seed yield. [ABSTRACT FROM AUTHOR]

Preparation of a series of cis -γ-fluorophenyl-β-phenyl-α-methylene-γ-butyrolactones is reported via ‘allylboration’ of fluorobenzaldehydes with ( E )-methyl 3-phenyl-2-((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)methyl)acrylate. The corresponding trans-γ-fluorophenyl lactones were prepared either (i) via ‘allylboration’ using the ( Z )-reagents or (ii) via an indium triflate-mediated isomerization of the cis -products. The difficulty in isomerizing difluorinated cis -products confirms the probable intermediacy of carbocations. Finally, the synthesis of cis -β-fluorophenyl-γ-phenyl-α-methylene-γ-butyrolactones was achieved via an indium-catalyzed allylation–lactonization of aldehydes with ( Z )-2-(bromomethyl)-3-(fluorophenyl)acrylates. [ABSTRACT FROM AUTHOR]

Genetically pure seeds of groundnut cv. VRI 2 were obtained from the Oilseed Research Station, Virudhachalam. The bulk seeds were graded for uniformity using 18/64" size sieve and were imposed with various physical seed enhancement techniques. The treated seeds along with control were stored in cloth bag and 700 gauge polythene bag under ambient condition of Annamalai nagar for a period of 10 months and were evaluated for seed quality characters viz., moisture content, germination per cent, oil content and electrical conductivity at bimonthly intervals. The study revealed that the seeds treated with halogen slurry treatment and stored in 700 gauge polythene bag registered low moisture content (8 %), electrical conductivity (0.529 dsm-1), high germination percentage (74 %) and oil content (43 %) when compared to control. It was also noted that they maintained the minimum seed certification standard upto 10 months of storage. [ABSTRACT FROM AUTHOR]

Analytical closed-form expressions for harmonic distortion factors corresponding to various pulsewidth modulation (PWM) techniques for a two-level inverter have been reported in the literature. This paper derives such analytical closed-form expressions, pertaining to centered space-vector PWM (CSVPWM) and eight different advanced bus-clamping PWM (ABCPWM) schemes, for a three-level neutral-point-clamped (NPC) inverter. These ABCPWM schemes switch each phase at twice the nominal switching frequency in certain intervals of the line cycle while clamping each phase to one of the dc terminals over certain other intervals. The harmonic spectra of the output voltages, corresponding to the eight ABCPWM schemes, are studied and compared experimentally with that of CSVPWM over the entire modulation range. The measured values of weighted total harmonic distortion (WTHD) of the line voltage \bf V\bf WTHD are used to validate the analytical closed-form expressions derived. The analytical expressions, pertaining to two of the ABCPWM methods, are also validated by measuring the total harmonic distortion (THD) in the line current \bf I\bf THD on a 2.2-kW constant volts-per-hertz induction motor drive. [ABSTRACT FROM PUBLISHER]

Novel switching sequences have been proposed recently for a neutral-point-clamped three-level inverter, controlled effectively as an equivalent two-level inverter. It is shown that the four novel sequences can be grouped into two pairs of sequences. Using each pair of sequences, a hybrid pulsewidth modulation (PWM) technique is proposed, which deploys the two sequences in appropriate spatial regions to reduce the current ripple. Further, a third hybrid PWM technique is proposed which uses all the five sequences (including the conventional sequence) in appropriate spatial regions. Each proposed hybrid PWM is shown, both analytically and experimentally, to outperform its constituent PWM methods in terms of harmonic distortion. In particular, the third proposed hybrid PWM reduces the total harmonic distortion considerably at low- and high-speed ranges of a constant volts-per-hertz induction motor drive, compared to centered space vector PWM. [ABSTRACT FROM AUTHOR]