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The present study examines stigma removal in the context of strategic industries. Strategic industries are critical from a national interest perspective and may not be able to engage in conventional stigma management strategies, such as concealment, dilution and coopting stakeholders, identified in extant literature. The present in‐depth qualitative study of the Indian civilian nuclear energy industry, a strategic industry within the Government of India, identifies two strategies, namely dependency reduction and category repositioning through responsible behaviour, employed in order to eradicate a global level stigma. The study concludes with implications for strategic industries and stigma management literature. [ABSTRACT FROM AUTHOR]

In this work, a multilevel 42-sided polygonal space vector structure for suppression of lower order harmonics for open-end induction motor (OEIM) drive applications is proposed. The proposed power circuit topology consists of two inverters feeding an OEIM from either side. The main inverter fed with a single dc-link providing active power for motoring operation is switched at low switching frequency. The secondary inverter fed with a capacitive supply is switched at high frequency to suppress lower order harmonics upto 39th order, up to the base speed of operation allowing maximum utilization of the dc-link. The advantages of lower order harmonic suppression in motor phase voltage, for polygonal space vector structures, are combined with multilevel inverter topology. This offers various advantages like multilevel operation with low inverter switching for the main power delivery inverter and harmonic suppression throughout the modulation range. The low switching frequency primary inverter generates harmonics of the order $6*k \pm 1$ , where $k = 1, 2, 3,{\ldots }$. The harmonics are suppressed by the capacitor-fed secondary inverter, which supplies only reactive power for suppression of lower order harmonics in motor phase voltage. Use of a single dc-link facilitates four-quadrant operation of the inverter. The proposed scheme is validated for steady-state and dynamic performance by experimental results. [ABSTRACT FROM AUTHOR]

Generating dense multilevel voltage space structure using polygons of higher sides is one of the novel and elegant method to suppress low-order harmonics and to obtain refined sinusoidal voltages using voltage source inverters for variable frequency drive application without passive filters. Apart from the advantages of conventional multilevel inverter topologies, schemes generating polygonal voltage space vector structure can equip full dc-bus utilization, low switching frequency strategies to eliminate low-order harmonics, and increased linear modulation range. In this paper, an induction motor drive scheme generating a highly dense multilevel 24-sided polygonal voltage space vector structure using a single dc source, which can eliminate harmonics till 23rd order from phase voltages, is presented. Cascaded power circuit topology with a flying capacitor inverter fed with a dc source and two low voltage floating capacitor fed H-bridge inverters is used. Detailed experimentally validated results, under scalar as well as indirect rotor field oriented control of induction motor are provided. Studies on voltage ripple and reactive energy in various floating capacitors, harmonic performance of output voltage for wide range of speed operation, are also included. [ABSTRACT FROM AUTHOR]

This paper proposes a new 7-level inverter topology for induction motor drives. It is a hybrid topology formed by cascading a 5-level active neutral-point-clamped inverter with a 3-level T-type converter. It is obtained using low-voltage semiconductor devices with voltage blocking capability of Vdc/3 and Vdc/6. The topology uses three floating capacitors per phase, which are balanced within a pulsewidth modulation (PWM) switching duration using switching-state redundancies for each pole-voltage level. Topology forms two stacks at the front-end, which requires individual symmetrical dc source. The analysis of switching loss and conduction loss is performed and compared with some of the existing 7-level multi-level inverters reported in various literatures to show the advantages of the proposed topology. Furthermore, the single dc source operation with two stacked capacitors and closed-loop control of neutral-point voltage using symmetrical six-phase induction motor is proposed. The voltage-control algorithms for floating capacitors and dc-link stacked capacitors are proposed, which are independent of load power factor and modulation index. Open-loop V/f and closed-loop rotor field oriented control are performed, and various results at steady and transient states are presented to validate the aforementioned claims. [ABSTRACT FROM AUTHOR]

Spectrum scarcity and under-utilization of the apportioned spectral resources by the licensed users have led to the introduction of a new communication paradigm called Cognitive radio (CR). This allows the unlicensed users to exploit the existing wireless spectrum opportunistically. However, the technology offers many challenges and spectrum sensing is one among them. For instance, narrowband spectrum sensing techniques provide spectral opportunities over a narrow frequency range and cannot identify individual spectral opportunities over a wide frequency band. In order to achieve a higher opportunistic throughput, CR is required to have a broader spectral awareness that can potentially be achieved by exploiting more spectral opportunities over a wideband spectrum. Due to many challenges that wideband spectrum sensing offers, it has become a field of interest for many researchers. Conventional wideband spectrum sensing techniques using Nyquist sampling rates, for instance, are infeasible, as they require high-speed analog-to-digital converters (ADCs). A more innovative approach based on sub-Nyquist sampling has thus become an area of extensive research in both academia and industry. This paper is a careful study and evaluation of some of the major sub-Nyquist wideband sensing techniques. Further, we introduce two novel sub-Nyquist sensing techniques and finally some open research challenges in general. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method for instantaneous balancing of neutral-point (NP) voltages with stacked multilevel inverters (MLIs) for variable-speed drives. The stacked MLI uses series-connected dc sources and NPs (connecting points of dc sources) to obtain the desired levels. The balancing of NP voltages are obtained by using a low-voltage-capacitor-fed cascaded H-bridge (CHB) per phase of a symmetrical six-phase induction machine (IM), which ensures zero current drawn from NPs (at any given instant). Since no current is drawn from NPs, the single dc-link operation with stacked capacitors is also possible. The scheme is suitable for applications, where low-voltage dc sources and batteries are stacked to form a dc link. A variable-speed operation is done using a seven-level inverter scheme for a symmetrical six-phase IM, which is formed by three dc-link stacked capacitors cascaded with two low-voltage-capacitor-fed CHBs per phase. Furthermore, the method is extended for an open-end IM to obtain a seven-level common-mode eliminated space vector structure using a single dc link. The generalization of this method for any stacked $n$ -level inverter without NP voltage deviation is also presented in this paper. The experimental results and analysis are included to validate the proposed method. [ABSTRACT FROM AUTHOR]

Conventional two-level as well as multilevel voltage-source-inverter topologies with a hexagonal voltage-space vector structure generate low-order harmonics in the machine terminal voltages when operated beyond the linear modulation range in variable speed drive application. Progressing from hexagonal to a higher sided polygonal voltage-space-vector structure (VSVS) suppresses significant low-order harmonics throughout the modulation range. In addition, the linear modulation range will also be enhanced very near to the base speed. In this paper, for the first time, the generation of a multilevel 24-sided VSVS using a single dc source for induction-motor drives is proposed. A cascaded topology with a dc-source-fed flying-capacitor inverter and two low-voltage capacitor-fed H-bridge cells forms the power circuit. The features and advantages of the proposed scheme are validated through experimental results and discussions. [ABSTRACT FROM AUTHOR]

In this study, an empirical mode decomposition (EMD) technique has been applied for EEG signals to identify a neurological disease state qualified as encephalopathy. The EMD technique is an efficient method for decomposing nonstationary and nonlinear signals, which makes it suitable for biosignal processing. This technique generates various components of the signal called intrinsic mode functions (IMFs) whose features are examined for the diagnosis of the disease. We found significant differences between the healthy and patient groups for both statistical and nonlinear parameters of IMFs of the recorded EEGs, which makes those suitable for the diagnosis of encephalopathy. Statistical values, namely minimum, maximum, mean, and standard deviation, and nonlinear parameters, namely approximate entropy and sample entropy of the IMFs, were calculated. Both these features were fed to a Support Vector Machine (SVM) classifier, and their performance parameters were evaluated. It is concluded that statistical parameters, as well as nonlinear parameters of the EEG IMFs, are prospective potential features for automated diagnosis of encephalopathy. [ABSTRACT FROM AUTHOR]

Purpose: To assess the impact of care at foster homes on the health-related quality of life (HRQOL) of children living with HIV (CLHIV), attending a referral ART Centre, and to compare their HRQOL with children living in their own homes.Methods: A cross-sectional study was conducted in 144 CLHIV between 5 and 18 years of age, attending a referral ART Centre in South India to assess their HRQOL using the standard PedsQL™ 4.0 questionnaire. Data were then analysed to compare the HRQOL of children living in foster homes to those children living in their own homes. The child report and the parent proxy-report on the child's HRQOL were also compared to see for any differences in their perspectives.Results: 56.25% CLHIV were brought up in different foster homes. In the child's self-report, the mean HRQOL was higher for children living in foster homes [physical score (76.54 ± 12.40), psychosocial score (71.41 ± 12.40) and total score (73.20 ± 11.13)] when compared to children living in their own homes [physical score (75.09 ± 14.76), psychosocial score (70.60 ± 13.48) and total score (72.17 ± 12.00)]. There was no statistically significant difference in the HRQOL between these two groups (p > 0.05). In the parent proxy-report also, there was no statistically significant difference in the HRQOL in all the three scores. The child self-report depicted a significantly higher HRQOL in all the domains compared to the parent proxy-report (p < 0.05).Conclusions: HRQOL of children living in foster homes is at par with the quality of life enjoyed by children living in their own homes. Foster care manages to provide a reasonable HRQOL in CLHIV, and has become an inseparable component of quality health care delivery for these children. [ABSTRACT FROM AUTHOR]

This paper proposes a novel 49-level stacked inverter topology for drives. The 49 levels are achieved by stacking three 17-level inverters. Each of the 17-level inverter is developed by cascading a flying capacitor (FC) inverter with three capacitor-fed H-bridges. The device count can be reduced by making the FC and the three cascaded H-bridges common to the dc link in each phase using selector switches in between them. The selector switches need to operate at fundamental frequency only. Also, the devices need to block very low voltages. Hence, MOSFETs can be used. This topology requires three dc sources, each of V\text{dc} /6 only, which can be replaced with stacked batteries for electric vehicle applications. The reduction in the dc voltage requirement is achieved by using a normal symmetric six-phase induction motor with parallel connection of the opposite phase windings. All the floating capacitors in the topology can be balanced irrespective of any modulation index or load power factor. Due to the high number of voltage levels, nearest level control can be used instead of pulse width modulation, which reduces the switching losses. The $dv/dt$ during the inverter operation is also less. Detailed experimental results at different speeds of operation and during transients ensure that the novel topology can be a viable option for high-power adjustable speed drives. [ABSTRACT FROM PUBLISHER]

Assessment of health-related quality of life (HRQoL) in children with HIV is crucial to improve the psychosocial well-being of this vulnerable population. The objective of this study was to assess the HRQoL of children with HIV infection aged between 5 and 18 years. The study was conducted in 144 children with HIV attending an antiretroviral therapy (ART) center in Karnataka to assess the HRQoL, using the PedsQL questionnaire. Total 144 children were included in the study, who had HRQoL with good physical (75.99 ± 13.46), psychosocial (71.01 ± 12.83), and total (72.43 ± 12.73) scores according to the child's perspective. Number of boys and children raised in foster homes were 51.3% (74) and 56% (81), respectively. Even though all children had complete adherence and had a good immunologic and clinical profile, we found that their HRQoL did not vary with stage of infection, duration of treatment, or immunologic status. Our findings underscore the importance of familycentered care for children living with HIV and advocate enhancing psychosocial and mental development to improve the HRQoL of children. [ABSTRACT FROM AUTHOR]

Rasburicase is a novel drug used during the management of tumor lysis syndrome. In countries with limited resources, it is frequently given at a lower dose and only for the treatment of established tumor lysis syndrome and not as prophylaxis. A retrospective study was conducted in the department of pediatric oncology at a tertiary referral oncology center in south India to analyze the use of rasburicase over the past 3 years. Data of all the 18 children (< 14 years of age) who were given rasburicase for the management of hyperuricemia were collected and analyzed. With a mean rasburicase dose of 0.085 mg/kg, hyperuricemia was managed efficiently without the need for a hemodialysis in 16 children (88.8 %). The fall in mean serum uric acid levels after the administration of a single dose of rasburicase at 4, 24, and 48 hours was 31.18 %, 64.8 %, and 74.5 %, respectively. Rasburicase efficiently decreases the uric acid levels to a normal level within a short period. In resource-limited settings, rasburicase at a lower dose is a promising option for managing hyperuricemia in the event of a tumor lysis syndrome. [ABSTRACT FROM AUTHOR]

Tuberculous adenitis presenting as an isolated cold abscess in the parapharyngeal space is very uncommon and has not been reported in the paediatric age group; presentation as a retropharyngeal abscess, however, is well known. Nine-year-old boy with a progressively increasing swelling on the right side of the neck for 2 months was referred with a clinical diagnosis of neuroblastoma. Surgical exploration of the parapharyngeal space by needle aspiration yielded a cheesy material and Mycobacterium tuberculosis was detected by DNA TB PCR. Tuberculosis should always be considered in the differential diagnosis of a cervical swelling in a child. [ABSTRACT FROM AUTHOR]

Multilevel inverters with dodecagonal (12-sided polygon) voltage space vector (SV) structures have advantages like extension of linear modulation range, elimination of fifth and seventh harmonics in phase voltages and currents for the full modulation range including extreme 12-step operation, reduced device voltage ratings, lesser dv/dt stresses on devices and motor phase windings resulting in lower EMI/EMC problems, and lower switching frequency—making it more suitable for high-power drive applications. This paper proposes a simple method to obtain pulsewidth modulation (PWM) timings for a dodecagonal voltage SV structure using only sampled reference voltages. In addition to this, a carrier-based method for obtaining the PWM timings for a general N-level dodecagonal structure is proposed in this paper for the first time. The algorithm outputs the triangle information and the PWM timing values which can be set as the compare values for any carrier-based hardware PWM module to obtain SV PWM like switching sequences. The proposed method eliminates the need for angle estimation, computation of modulation indices, and iterative search algorithms that are typical in multilevel dodecagonal SV systems. The proposed PWM scheme was implemented on a five-level dodecagonal SV structure. Exhaustive simulation and experimental results for steady-state and transient conditions are presented to validate the proposed method. [ABSTRACT FROM PUBLISHER]

In this paper, a multilevel dodecagonal voltage space vector structure with nineteen concentric dodecagons is proposed for the first time. This space vector structure is achieved by cascading two sets of asymmetric three-level inverters with isolated H-bridges on either side of an open-end winding induction motor. The dodecagonal structure is made possible by proper selection of dc link voltages and switching states of the inverters. The proposed scheme retains all the advantages of multilevel topologies as well as the advantages of dodecagonal voltage space vector structure. In addition to that, a generic and simple method for calculation of pulsewidth modulation timings using only sampled reference values ( $v_\alpha$ and $v_\beta$) is proposed. This enables the scheme to be used for any closed-loop application such as vector control. In addition, a new method of switching technique is proposed, which ensures minimum switching while eliminating the fifth- and seventh-order harmonics and suppressing the eleventh and thirteenth harmonics, eliminating the need for bulky filters. The motor phase voltage is a 24-stepped waveform for the entire modulation range thereby reducing the number of switchings of the individual inverter modules. Experimental results for steady-state operation, transient operation, including start-up have been presented and the results of fast Fourier transform analysis is also presented for validating the proposed concept. [ABSTRACT FROM PUBLISHER]

Malaria remains an overwhelming problem with around 214 million cases reported worldwide each year. It remains a major health problem in the tropical developing countries and India accounts for 70% of the total malaria incidence in the Southeast Asia region. Even though, artesunate, a novel drug used in the treatment of chloroquine- resistant cases of Plasmodium falciparum infection causes transient transaminitis (elevation of alanine and aspartate transaminases), hepatitis and hepatic encephalopathy are very rare. We encountered a child with falciparum malaria, who accidently ingested artesunate tablets (16 mg/kg) and developed hepatic encephalopathy with clinical and biochemical improvement in a matter of 4 to 5 days. There are only a few reports of children with malaria developing hepatic encephalopathy, with or without coinfection with hepatotropic viruses. Also, there are no reports of hepatic encephalopathy secondary to artesunate overdose, creating a dilemma in diagnosis and management. [ABSTRACT FROM AUTHOR]

In India, the clinical guidelines and laws governing consent for blood transfusion in a minor are meager and vague. In an elective situation, whether the parents can make a decision for the child on his/her behalf or whether the doctor has the right to make the decision in the best interests of the child is not clear. We present the case scenario of a child belonging to Jehovah's Witness denomination diagnosed with Burkitt lymphoma. His parents were in a dilemma whether to opt for blood transfusion or not. In the absence of laws and guidelines in this context, and considering the complications that he developed during the treatment period, it was very challenging for us to manage the situation both medically and medico-legally. This situation highlights the need for framing consensus guidelines/laws regarding elective blood transfusion in a minor to make health-care delivery, smooth, transparent and flawless. [ABSTRACT FROM AUTHOR]

Multilevel inverters with dodecagonal (12-sided polygon) voltage space vector structure have advantages, such as complete elimination of fifth and seventh harmonics, reduction in electromagnetic interference, reduction in device voltage ratings, reduction of switching frequency, extension of linear modulation range, etc., making it a viable option for high-power medium-voltage drives. This paper proposes two power circuit topologies capable of generating multilevel dodecagonal voltage space vector structure with symmetric triangles (for the first time) with minimum number of dc-link power supplies and floating capacitor H-bridges. The first power topology is composed of two hybrid cascaded five-level inverters connected to either side of an open-end winding induction machine. Each inverter consists of a three-level neutral-point-clamped inverter, which is cascaded with an isolated H-bridge making it a five-level inverter. The second topology is for a normal induction motor. Both of these circuit topologies have inherent capacitor balancing for floating H-bridges for all modulation indexes, including transient operations. The proposed topologies do not require any precharging circuitry for startup. A simple pulsewidth modulation timing calculation method for space vector modulation is also presented in this paper. Due to the symmetric arrangement of congruent triangles within the voltage space vector structure, the timing computation requires only the sampled reference values and does not require any offline computation, lookup tables, or angle computation. Experimental results for steady-state operation and transient operation are also presented to validate the proposed concept. [ABSTRACT FROM PUBLISHER]

Voltage source inverter (VSI)-fed six-phase induction motor (IM) drives have high $6n\pm 1$, n = \odd-order harmonic currents. This is because these currents, driven by the corresponding harmonic voltages in the inverter output, are limited only by the stator leakage impedance, as these harmonics are absent in the back electromotive force of the motor. To suppress the harmonic currents, either bulky inductive harmonic filters or complex pulsewidth modulation (PWM) techniques have to be used. This paper proposes a harmonic elimination scheme using switched capacitor filters for a VSI-fed split-phase IM drive. Two 3-phase inverters fed from capacitors are used on the open-end side of the motor to suppress $6n\pm 1$, n = \odd-order harmonics. A PWM scheme that can suppress the harmonics as well as balance the capacitor voltage is also proposed. The capacitor fed inverters are switched so that the fundamental voltage is not affected, and the fundamental power is always drawn from the main inverters. The proposed scheme is verified with a detailed experimental study. The effectiveness of the scheme is demonstrated by comparing the results with those obtained by disabling the capacitor fed inverters. [ABSTRACT FROM PUBLISHER]

Multilevel inverters with hexagonal and dodecagonal voltage space vector structures have improved harmonic profile compared to two-level inverters. Further improvement in the quality of the waveform is possible using multilevel octadecagonal (18-sided polygon) voltage space vectors. This paper proposes an inverter circuit topology capable of generating multilevel octadecagonal voltage space vectors, by cascading two asymmetric three-level inverters. By the proper selection of dc-link voltages and the resultant switching states for the inverters, voltage space vectors, whose tips lie on three concentric octadecagons, are obtained. The advantages of octadecagonal voltage space vector-based pulsewidth modulation (PWM) techniques are the complete elimination of fifth, seventh, eleventh, and thirteenth harmonics in phase voltages and the extension of linear modulation range. In this paper, a simple PWM timing calculation method is also proposed. Experimental results have been presented in this paper to validate the proposed concept. [ABSTRACT FROM PUBLISHER]

A new hybrid five-level inverter topology with common-mode voltage (CMV) elimination for induction motor drive is proposed in this paper. This topology has only one dc source, and different voltage levels are generated by using this voltage source along with floating capacitors charged to asymmetrical voltage levels. The pulsewidth modulation (PWM) scheme employed in this topology balances the capacitor voltages at the required levels at any power factor and modulation index while eliminating the CMV. This inverter has good fault-tolerant capability as it can be operated in three- or two-level mode with CMV elimination, in case of any failure in the H-bridges. More voltage levels with CMV elimination can be realized from this topology but only in a limited range of modulation index and power factor. Extensive simulation is done to validate the PWM technique for CMV elimination and balancing of the capacitor voltages. The experimental verification of the proposed inverter-fed induction motor is carried out in the linear modulation and overmodulation regions. The steady-state and transient operations of the drive are verified. The dynamics of the capacitor voltage balancing is also tested. The experimental results demonstrate that the proposed topology can be considered for industrial drive applications. [ABSTRACT FROM AUTHOR]

This paper proposes a current-error space-vector-based hysteresis controller with online computation of boundary for two-level inverter-fed induction motor (IM) drives. The proposed hysteresis controller has got all advantages of conventional current-error space-vector-based hysteresis controllers like quick transient response, simplicity, adjacent voltage vector switching, etc. Major advantage of the proposed controller-based voltage-source-inverters-fed drive is that phase voltage frequency spectrum produced is exactly similar to that of a constant switching frequency space-vector pulsewidth modulated (SVPWM) inverter. In this proposed hysteresis controller, stator voltages along α- and β-axes are estimated during zero and active voltage vector periods using current errors along α- and β-axes and steady-state model of IM. Online computation of hysteresis boundary is carried out using estimated stator voltages in the proposed hysteresis controller. The proposed scheme is simple and capable of taking inverter upto six-step-mode operation, if demanded by drive system. The proposed hysteresis-controller-based inverter-fed drive scheme is experimentally verified. The steady state and transient performance of the proposed scheme is extensively tested. The experimental results are giving constant frequency spectrum for phase voltage similar to that of constant frequency SVPWM inverter-fed drive. [ABSTRACT FROM AUTHOR]

The famous chaotic circuit known as Chua's oscillator, despite the robustness of the chaotic behavior to parametric mismatches, requires the construction of noncommercial valued inductor. A low cost inductorless version of Chua's oscillator is presented. The chaotic behavior of the circuit is verified by PSpice simulation and also by experimental study on a circuit breadboard. The results lead to excellent agreement with each other and with the results of previous investigators. Experimental results on the possibility of controlling chaos in the modified Chua's oscillator by the inherent feedback mechanism are also reported. [ABSTRACT FROM AUTHOR]

In this study we describe how to build an inductorless version of the classic Chua's circuit. A suitable inductor for Chua's circuit is often hard to procure. The required inductor for the circuit is designed using simple circuit elements such as resistors, capacitors and operational amplifiers. The complete circuit can be implemented by using off-the-shelf components, and it can readily be integrated on a single chip. This design of Chua's circuit allows the original dynamics to be slowed down to just a few hertz, enabling implementation of sophisticated control schemes without severe time restrictions. Another novel feature of the circuit is that losses associated with capacitors due to leakages can easily be compensated by providing negative resistance using the same setup. The chaotic behaviour of the circuit is verified by PSpice and Multisim simulation and also by experimental study on a circuit breadboard. The results give excellent agreement with each other and with the results of previous investigators. [ABSTRACT FROM AUTHOR]

Cascaded multilevel inverters synthesize a medium-voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic allows one to achieve high-quality output voltages and input currents and also outstanding availability due to their intrinsic component redundancy. Due to these features, the cascaded multilevel inverter has been recognized as an important alternative in the medium-voltage inverter market. This paper presents a survey of different topologies, control strategies and modulation techniques used by these inverters. Regenerative and advanced topologies are also discussed. Applications where the mentioned features play a key role are shown. Finally, future developments are addressed. [ABSTRACT FROM AUTHOR]

An inverter scheme with 18-sided polygonal voltage space-vector structure is proposed for induction motor drive applications. An open-end winding configuration is used for the drive scheme. The motor is fed from one end with a conventional two-level inverter and from the other end with a three-level inverter, realised by cascading two conventional two-level inverters. The inverters are fed with asymmetrical DC-link voltages. A simple linear PWM control scheme up to 18-step mode is proposed, based only on the motor reference phase amplitudes. The proposed scheme gives an increased modulation range with the elimination of the 5th, 7th, 11th and 13th-order harmonics, for the entire modulation range, when compared with any conventional schemes. The absence of low-order harmonics gives nearly sinusoidal currents throughout the modulation range, and makes PWM control of voltage very simple, with low inverter switching frequencies, especially in the extreme modulation range. [ABSTRACT FROM AUTHOR]

The effect of sodium chloride concentration (3, 4, 5, 6, 8, 10 and 12%) and storage temperatures (4°C, 10°C, 15°C and 30°C) on toxin production by Clostridium, botulinum isolated from tropical fish was studied in anaerobic cooked meat medium. The combined effect of sodium chloride (3, 5%), low pH (5.5) and low temperature (15°C) on toxin production by C. botulinum was also examined. The toxicity was tested by mouse bioassay. An increase in lag phase was noticed by increasing the salt concentration. At 30°C, spores of C. botulinum type E were able to grow and produce toxin up to 3% salt (aw = 0.976), whereas for types C and D the limiting salt concentration was 4-5% (aw = 0.97-0.974) and for types A and B it was 8% (aw = 0.952). By lowering the storage temperature, an increase in lag phase and time to toxicity was noticed for type Eat 3% salt and for types A, C and D at 5% salt level. The probability of growth and toxin production at 5% salt decreased as the pH and storage temperature (combined stress) was decreased. [ABSTRACT FROM AUTHOR]

The issues in synchronised implementation of space vector-based pulse width modulation (SVPWM) signal generation are addressed on a conventional DSP platform. With the present day digital signal processors (DSPs) with clock over 10 MHz, it is possible to include additional tasks for synchronisation in the interrupt service routine (ISR). Also, the task of the synchronisation can be easily accommodated within the same ISR without disturbing the time critical pulse width modulation (PWM) operation. The authors systematically present the additional software requirements to determine the time period proportional to the half carrier switching time interval that is required for the synchronisation. First, the DSP implementation of the conventional multi-level SVPWM based on the sampled amplitudes of reference voltages is presented and then the additional requirements to maintain the PWM in synchronisation are discussed. The simulation results as well as experimental results are presented for a five-level PWM signal generation. A five-level inverter configuration, using a 1.5 kW open-end winding induction motor drive, is used for experimentally verifying the SVPWM. [ABSTRACT FROM AUTHOR]

This study was undertaken to determine the influence of temperature and pH on growth and time to toxicity of spores of Clostridium botulinum types isolated from tropical fish. Anaerobic meat medium with varying temperatures (4-30°C) and pH values (4.5 to 7.0) were used and toxicity was tested by mouse bioassay. An increase in lag phase was noticed by lowering the growth temperature from 30°C to 4°C and the pH from 7.0 to 4.6. The probability of toxin production increased with storage time, but decreased as either the pH or storage temperature and pH (combined stress) was decreased. The results indicated the effect of pH in controlling toxin production by C. botulinum spores in refrigerated foods with pH 5.0 or < 5.0. [ABSTRACT FROM AUTHOR]

In this paper, a multilevel inverter system for an open-end winding induction motor drive is described. Multilevel inversion is achieved by feeding an open-end winding induction motor with two two-level inverters in cascade (equivalent to a three-level inverter) from one end and a single two-level inverter from the other end of the motor. The combined inverter system with open-end winding induction motor produces voltage spaces vector locations identical to a six-level inverter. A total of 512 space-vector combinations are available in the proposed scheme, distributed over 91 space-vector locations. The pro- posed inverter drive scheme is capable of producing a multilevel pulsewidth-modulation (PWM) waveform for the phase voltage ranging from a two-level waveform to a six-level waveform depending on the modulation range. A space-vector PWM scheme for the proposed drive is implemented using a 1.5-kW induction motor with open-end winding structure. [ABSTRACT FROM AUTHOR]

In this paper, a harmonic elimination and suppression scheme for a dual-inverter-fed open-end winding induction motor drive is presents. Two isolated dc-link sources with voltage ratio of approximately 1: 0.366 are required for the present drive. These two isolated dc links feeding two inverters to drive the open-end winding induction motor eliminate the triplen harmonic currents from the motor phase. The pulsewidth-modulation scheme proposed enables the cancellation of all the 5th- and 7th-order (6n ± 1, where n = 1,3,5, 7, etc.) harmonic voltages and suppresses the 11th- and 13th-order harmonic voltage amplitudes in the motor phase. voltage, in all modulation ranges. The next higher order harmonics present in the motor phase voltages are 23rd, 25th, 35th, 37th etc. (6n ± 1, n = 4, 6, etc). By using triangular carrier wave and proper modulating waves for each inverter, the open-end winding induction motor can be operated in the entire modulation range, eliminating all the 6n ± 1 harmonics (n = 1, 3, 5, 7, etc.) coupled with 11th and 13th harmonic suppression The proposed scheme also gives a smooth transition to the overmodulation region. [ABSTRACT FROM AUTHOR]

Presents a topology for a voltage-space phasor generation equivalent to a five-level inverter for an open-end winding induction motor. Structure of the proposed inverter; Use of open-end winding induction motor; Absence of neutral point fluctuations.

A power circuit configuration to realise three-level inversion is proposed. Three-level inversion is realised by connecting two two-level inverters in cascade, in the proposed configuration. An isolated DC power supply is used to supply each inverter in this power circuit. Each DC-link voltage is equal to half of the DC-link voltage in a conventional NPC (neutral point clamped) three-level inverter topology. Neutral point fluctuations are absent, and fast recovery neutral clamping diodes are not needed. The proposed inverter scheme produces 64 space-vector combinations distributed over 19 space-vector locations as compared to 27 combinations in a conventional three-level topology. The present power circuit can be operated as a two-level inverter in the range of lower modulation, by clamping one inverter to a zero state and by switching the other inverter. When compared to the H-bridge topology, this circuit needs one power supply less. A space vector based PWM scheme is used for the experimental verification of the proposed topology. [ABSTRACT FROM AUTHOR]

Fish play an important role in the nutrition of people in India. Per capita availability of fish in the country is 9.5 kg with production at 5.8 million tonnes during 1999-2000. This production level makes India the second largest aquaculture producing country in the world, China is the leading aquaculture producer. India cultures many different species including Indian major carps (catla, Catla catla; rohu, Labeo rohita; naini, Cyprinus mrigala; and calbasu, Labeo calbasu), marine shrimp, freshwater shrimp, oysters, green and brown mussels, and pearl oysters for domestic and international markets. To meet the increased demand for fisheries products by 2010, India must increase its current level of production to 7-8 million tonnes per year. With marine fishery production/ capture steady at 3 million tonnes per year, inland aquaculture production must increase from its current level of 2.5 million tonnes to 5 million tonnes by 2010. India must intensify culture production methods for this increased production values to be achieved. [ABSTRACT FROM PUBLISHER]

The sensitivity of Oreochromis mossambicus to Clostridium botulinum toxin types A–E was investigated. All five toxin types were toxic to O. mossambicus. In the case of toxin types A–D, O. mossambicus was considerably more resistant than mice and, in the case of type E toxin, fish were more sensitive. The minimum intraperitoneal (i.p.) dose of type E toxin for fish was half the minimum lethal dose for mice. The results of the study suggest that good hygiene should be maintained in fish/shrimp farms to keep contamination at a low level. [ABSTRACT FROM AUTHOR]

Electrolaryngeal speech, for persons who have lost their larynx, suffers from the drawback of susceptibility to acoustic noise, which includes inherent electrolarynx motor noise as well as environmental noise. Interactions with electrolarynx users motivated the authors to investigate a crucial drawback of electrolaryngeal speech: degradation of electrolaryngeal speech under noisy environments. The effect of contemporary methods of speech enhancement, viz. noise power spectral density estimation based d-dimensional amplitude trimmed estimation (DATE), and non-negative matrix factorization (NMF) based algorithms, were studied and evaluated for electrolaryngeal speech degraded by noise. Electrolaryngeal speech was corrupted using three types of noisy scenarios at low signal to noise ratios (0, −5 and −10 dB SNR). Objective testing based on the perceptual evaluation of speech quality (PESQ) standard, as well as subjective testing by 14 participants based on the ITU-T P.835 standard were performed. Word-centric intelligibility testing was also performed. The results indicated an improvement in the speech quality. The subjective testing results were further analyzed using one-way analysis of variance (ANOVA) and multiple paired comparison using Tukey's honest significant difference (HSD) criterion. The overall speech quality of NMF algorithms was found to be significantly higher than that of DATE-based algorithms for the test conditions. The results show that speech enhancement algorithms can aid in improving the electrolaryngeal user experience by reducing the effect of acoustic noise. [ABSTRACT FROM AUTHOR]

BSTRACT The effect of prolonged cold storage on muscle adenosine triphosphatase (ATPase) and lactate dehydrogenase (LDH) activities was studied in a variety of fresh water and brackish water fish. Decrease in enzyme activity was observed in all samples stored frozen (- 20°C) over a period of 180 days. Highly significant negative correlation was observed between enzyme activity and frozen storage period with mullet, pearlspot, milk fish and tilapia. Significant linear correlations were observed between decrease in enzyme activities and other biochemical indices and sensory scores. The results indicated that loss of activities of ATPase and LDH in fish muscle was significantly related to early changes in quality of frozen stored fish. [ABSTRACT FROM AUTHOR]

An introduction to articles discussed within the issue is presented, including the articles "Compensation of Nonlinearities in Diode-Clamped Multilevel Converters," by S. R. Minshull et al, "A Novel Space-Vector Current Control Based on Circular Hysteresis Areas of a Three-Phase Neutral-Point-Clamped Inverter," by T. Ghennam et al, and "A Five-Level Inverter Scheme for a Four-Pole Induction Motor Drive by Feeding the Identical Voltage-Profile Windings From Both Sides," by K. Sivakumar et al.

An introduction to the journal is presented in which the editors list the research areas related to multilevel inverters and cite the papers submitted for publication in the July 2010 issue of the journal, including "A Survey on Cascased Multilevel Inverters," "Survey on Fault Operation on Multilevel Inverters," and "New Active Stacked NPC Multilevel Converter: Operation and Features.

Deep-sea mining involves the extraction of valuable minerals from the ocean floor. The transportation of deep-sea mineral deposits from the seafloor to the surface is crucial for the success of deep-sea mining operations. The slurry pumping system is responsible for conveying a mixture of minerals, sediments, and water over significant distances. Designing a robust and efficient slurry pump necessitates meticulous consideration of various factors, including particle size, slurry concentration, system reliability, and more. This article presents a comprehensive, state-of-the-art review of airlift pumping, with a particular focus on three-phase flow systems. The manuscript is divided into two primary sections: an analytical approach and an experimental approach to the airlift system. The empirical methodologies discussed herein provide correlations for evaluating pump performance in both two-phase (air-water) and three-phase flow systems. Furthermore, the experimental findings shed light on how operational parameters impact system performance dynamics and flow regime transitions. Additionally, the paper discusses the utilization and advancement of airlift pumping systems in deep-sea mining operations. The technological advancements and challenges addressed within this paper offer valuable insights for improving the implementation methodologies for designing slurry pumping systems in the context of deep-sea mining operations. • Conducted a comprehensive review and presentation of airlift pumping systems, aiming to provide a thorough understanding of their mechanisms, advantages, and limitations for the vertical solid particle transport. • The empirical correlations for both two-phase and three-phase flow air-lift pumping systems are comprehensively presented, and their reliability is assessed through a comparative analysis with experimental results. • The experimental analyses presented by various authors have been thoroughly examined and organized in a table, including their variable geometrical and operational parameters, as well as significant findings. • The promising potential of air-lift pump systems in the emerging field of deep-sea mining is discussed in details. These discussions help us to understand the effective transport of solid particles from the ocean floor to the surface. [ABSTRACT FROM AUTHOR]

Modulation using a higher sided polygonal space vector structure (SVS) is an elegant method to increase the linear modulation range and to eliminate the undesired lower order harmonics from motor phase voltage. This article presents the generation of a dense 15-concentric 30-sided multilevel SVS using a single dc-link for an open end induction motor (OEIM) drive. The proposed scheme eliminates lower order harmonics till 25th order from motor phase voltage throughout the modulation range. The $dv/dt$ stress in the phase voltage applied to the motor will also be highly reduced owing to the multilevel structure. The pulsewidth modulation scheme employed utilizes the denseness of SVS and avoids iterative searches to find the triangle, which encompasses the tip of reference voltage vector, which are typical in multilevel polygonal SVS. The topology consists of an active dc-link fed three-level primary inverter and a capacitor fed five-level secondary inverter connected to either end of an OEIM. The primary inverter acts as the active power supplier for the drive and the secondary inverter filters out the undesirable lower order harmonics from motor phase voltage. The proposed scheme is experientially validated and the results are included in this article. [ABSTRACT FROM AUTHOR]

In this article, a multilevel inverter scheme to generate a 30-sided space vector structure (SVS) with congruent triangles is proposed. The 30-sided SVS eliminates all the lower order harmonics till 25th order from motor phase voltage throughout the modulation range. The proposed scheme is implemented using a single dc-link on an open-end induction motor (OEIM). The OEIM is fed with primary inverter from one end and secondary inverter from the other end. Primary inverter is fed from an active dc-link and supplies all the required active power for the scheme. Secondary inverter is a capacitor fed inverter, which acts as the switched capacitive filter. In this work, a simple algorithm is proposed, which calculates the timings required for a 2-level 30-sided SVS from sampled reference voltages. The algorithm requires only simple operations such as addition, multiplication, and comparisons. From the obtained timing values, the space vector location of three nearest multilevel 30-sided vectors and its time duration can be identified. The feasibility of the proposed scheme is proved by experimental results. [ABSTRACT FROM AUTHOR]

This article proposes an inverter topology for the first time for suppression of all lower order harmonics (5th, 7th, 11th, 13th, etc.) up to 39th harmonic. The lower order harmonic suppression is achieved by switching the 42-sided polygonal vectors, which eliminates harmonics in phase voltage without using a passive LC filtering technique. The power circuit topology uses a single dc-link supply for the primary inverter. The secondary inverter is fed with a capacitive supply. A novel topology is proposed for the dense six-level secondary inverter. The lower order harmonics in phase voltage are suppressed using the secondary inverter, which acts like a switched-capacitive filter. This article also proposes a novel capacitor voltage-balancing scheme for the first time, which achieves voltage balancing for secondary inverter capacitors. The voltages of secondary inverter capacitors are balanced using the power balance relationship between the primary inverter and the motor load. An experimental study of the topology and the capacitor-balancing scheme is presented for the validation of proposed scheme. [ABSTRACT FROM AUTHOR]

The grid-tied inverter synchronizes with the network on the basis of the instantaneous voltage phase angle. This angle is computed by the so-called synchronization algorithms. During grid disturbances, it is estimated with a certain accuracy, which varies for different disturbances and depends on the choice of algorithm. The tests presented here determine how to make an optimal selection of the synchronization algorithm. The research methods used are modeling, simulation and analysis of the results obtained. One of the most important outcomes is the determination of the root-mean-square sync error and its dynamics denotation. The research conclusions should be of particular interest to designers of distributed energy systems with a large number of inverter energy sources. [ABSTRACT FROM AUTHOR]