18 research outputs found
The missing link in English language teaching
The aim of this workshop is to provide participants with some teaching ideas on how the writing skill may be improved. This is done through error analysis, correction and vocabulary building. The first part of the workshop will explore different ways of identifying students’ weak areas in writing and how these areas may be corrected. The
second part will cover ways on how vocabulary building may be carried out, to help students improve their writing skill. The participants will have hands-on experience of
preparing materials for vocabulary building during the workshop
An energy efficient modified passive power filter for power quality enhancement in electric drives
In most industrial applications, AC drives are used. These drives require power electronic modules to convert AC to DC and also DC to AC. The power modules used for power conversion consist of power semiconductor switches. There is distortion in the voltage and current obtained from the power modules due to non-linear behaviors of semiconductor switches. To reduce the distortion in the input current, inductors are used along with the line impedance. A high value of inductance is required to maintain the percentage of THD within limits set by the latest standards. Along with the increased size and cost, it also reduces the power factor and output DC voltage at higher loads. The use of a passive power filter (PPF) is the conventional method followed for the reduction of percentage THD and promotion of the power factor. PPFs comprise passive elements such as the resistor, inductor, and capacitor. These passive elements are connected at the point of common coupling (PCC) in shunt to compensate for the harmonics present in the input current. In this study, a modified multi-tuned passive filter is considered to reduce the source current harmonics. A bridge rectifier with resistive load, three-phase induction motor drive, and linear resistive–inductive load is connected at the point of common coupling to analyze the harmonics present in the source current, and also unbalanced created in one phase. To achieve proper selection of the resistance value for the passive filter, the class topper optimization technique is used. To validate the simulation results obtained for the multi-tuned passive filter, the hardware is implemented with a three-phase AC induction motor drive load, in which the speed of the motor is controlled with voltage by a frequency control algorithm using an FPGA controller; The 50% THD is reduced by using the fifth-order filter alone, 75% by combining the fifth- and seventh-order filters, 85% by combining the 5th-, 7th-, 11th-, 13th-, and higher-order filters, and 90% for varying loads. For single-phase AC induction motor load, THD % is reduced to 4%, and for three-phase AC induction motor drive, THD % is reduced to 10% with the same value of the filter
Global, regional, and national under-5 mortality, adult mortality, age-specific mortality, and life expectancy, 1970–2016: a systematic analysis for the Global Burden of Disease Study 2016
BACKGROUND: Detailed assessments of mortality patterns, particularly age-specific mortality, represent a crucial input that enables health systems to target interventions to specific populations. Understanding how all-cause mortality has changed with respect to development status can identify exemplars for best practice. To accomplish this, the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) estimated age-specific and sex-specific all-cause mortality between 1970 and 2016 for 195 countries and territories and at the subnational level for the five countries with a population greater than 200 million in 2016.
METHODS: We have evaluated how well civil registration systems captured deaths using a set of demographic methods called death distribution methods for adults and from consideration of survey and census data for children younger than 5 years. We generated an overall assessment of completeness of registration of deaths by dividing registered deaths in each location-year by our estimate of all-age deaths generated from our overall estimation process. For 163 locations, including subnational units in countries with a population greater than 200 million with complete vital registration (VR) systems, our estimates were largely driven by the observed data, with corrections for small fluctuations in numbers and estimation for recent years where there were lags in data reporting (lags were variable by location, generally between 1 year and 6 years). For other locations, we took advantage of different data sources available to measure under-5 mortality rates (U5MR) using complete birth histories, summary birth histories, and incomplete VR with adjustments; we measured adult mortality rate (the probability of death in individuals aged 15-60 years) using adjusted incomplete VR, sibling histories, and household death recall. We used the U5MR and adult mortality rate, together with crude death rate due to HIV in the GBD model life table system, to estimate age-specific and sex-specific death rates for each location-year. Using various international databases, we identified fatal discontinuities, which we defined as increases in the death rate of more than one death per million, resulting from conflict and terrorism, natural disasters, major transport or technological accidents, and a subset of epidemic infectious diseases; these were added to estimates in the relevant years. In 47 countries with an identified peak adult prevalence for HIV/AIDS of more than 0·5% and where VR systems were less than 65% complete, we informed our estimates of age-sex-specific mortality using the Estimation and Projection Package (EPP)-Spectrum model fitted to national HIV/AIDS prevalence surveys and antenatal clinic serosurveillance systems. We estimated stillbirths, early neonatal, late neonatal, and childhood mortality using both survey and VR data in spatiotemporal Gaussian process regression models. We estimated abridged life tables for all location-years using age-specific death rates. We grouped locations into development quintiles based on the Socio-demographic Index (SDI) and analysed mortality trends by quintile. Using spline regression, we estimated the expected mortality rate for each age-sex group as a function of SDI. We identified countries with higher life expectancy than expected by comparing observed life expectancy to anticipated life expectancy on the basis of development status alone.
FINDINGS: Completeness in the registration of deaths increased from 28% in 1970 to a peak of 45% in 2013; completeness was lower after 2013 because of lags in reporting. Total deaths in children younger than 5 years decreased from 1970 to 2016, and slower decreases occurred at ages 5-24 years. By contrast, numbers of adult deaths increased in each 5-year age bracket above the age of 25 years. The distribution of annualised rates of change in age-specific mortality rate differed over the period 2000 to 2016 compared with earlier decades: increasing annualised rates of change were less frequent, although rising annualised rates of change still occurred in some locations, particularly for adolescent and younger adult age groups. Rates of stillbirths and under-5 mortality both decreased globally from 1970. Evidence for global convergence of death rates was mixed; although the absolute difference between age-standardised death rates narrowed between countries at the lowest and highest levels of SDI, the ratio of these death rates-a measure of relative inequality-increased slightly. There was a strong shift between 1970 and 2016 toward higher life expectancy, most noticeably at higher levels of SDI. Among countries with populations greater than 1 million in 2016, life expectancy at birth was highest for women in Japan, at 86·9 years (95% UI 86·7-87·2), and for men in Singapore, at 81·3 years (78·8-83·7) in 2016. Male life expectancy was generally lower than female life expectancy between 1970 and 2016, an
Randomized Clinical Trial of High-Dose Rifampicin With or Without Levofloxacin Versus Standard of Care for Pediatric Tuberculous Meningitis: The TBM-KIDS Trial
Background. Pediatric tuberculous meningitis (TBM) commonly causes death or disability. In adults, high-dose rifampicin may reduce mortality. The role of fluoroquinolones remains unclear. There have been no antimicrobial treatment trials for pediatric TBM.
Methods. TBM-KIDS was a phase 2 open-label randomized trial among children with TBM in India and Malawi. Participants received isoniazid and pyrazinamide plus: (i) high-dose rifampicin (30 mg/kg) and ethambutol (R30HZE, arm 1); (ii) high-dose rifampicin
and levofloxacin (R30HZL, arm 2); or (iii) standard-dose rifampicin and ethambutol (R15HZE, arm 3) for 8 weeks, followed by 10 months of standard treatment. Functional and neurocognitive outcomes were measured longitudinally using Modified Rankin Scale (MRS) and Mullen Scales of Early Learning (MSEL).
Results. Of 2487 children prescreened, 79 were screened and 37 enrolled. Median age was 72 months; 49%, 43%, and 8% had stage I, II, and III disease, respectively. Grade 3 or higher adverse events occurred in 58%, 55%, and 36% of children in arms 1, 2, and 3, with 1 death (arm 1) and 6 early treatment discontinuations (4 in arm 1, 1 each in arms 2 and 3). By week 8, all children recovered to MRS score of 0 or 1. Average MSEL scores were significantly better in arm 1 than arm 3 in fine motor, receptive language, and expressive language domains (P < .01).
Conclusions. In a pediatric TBM trial, functional outcomes were excellent overall. The trend toward higher frequency of adverse events but better neurocognitive outcomes in children receiving high-dose rifampicin requires confirmation in a larger trial.
Clinical Trials Registration. NCT02958709
Optimal Planning of PV Sources and D-STATCOM Devices with Network Reconfiguration Employing Modified Ant Lion Optimizer
This research emphasizes a meta-heuristic modified ant lion optimizer (MALO) optimization approach for the simultaneous utilization of DSTATCOM devices and distributed photovoltaic (PV) sources with network reconfiguration in a radial power distribution scheme. In a radial power distribution network with network reconfiguration, the majority of the research is based on constant power model analysis. However, it is noticed that load models have a substantial impact on the distributed PV sources and the DSTATCOM device’s optimal size and position. The effect of the constant power (CP) and polynomial (ZIP) with load growth load models for the simultaneous insertion of distributed PV sources and DSTATCOM devices with network reconfiguration is examined in this research work for power system planning. The penetration levels of distributed PV sources considered for the investigation are 25%, 50%, 75%, and 100%. The principal objective of this research is to reduce network total power losses, enhance the voltage magnitude profile at all buses, and reduce the overall operating cost while adhering to equality and inequality constraints. The proposed algorithm is verified on 118-node test systems. The investigation is carried out for planning network upgrading to a high-voltage distribution system (HVDS) on 317 nodes in the rural Bangalore Electricity Supply Company Limited (BESCOM) radial distribution scheme. The simulated results obtained with this method are validated with the BAT algorithm and techniques available in the literature. It is observed that in the IEEE 118-bus system, via the simultaneous placement and sizing of PV sources considering a 25% penetration level and DSTATCOM devices during network reconfiguration, the total power loss reduction is 41.47% and 42.98% for the constant power model and ZIP with the load growth model. For the 317-bus system, the total power loss reduction observed for 11 kV is 49.77% and 59.34% for the constant power model and ZIP model with load growth. Similarly, for the 22 kV system, the power loss reduction observed is 51.69% and 55.75% for the constant power model and ZIP with the load growth model
Design of Controller for Bidirectional Non-isolated High Gain Converter in EV Application
An interface between a DC supply and an electric vehicle's drive fed by an inverter is a bidirectional
DC-DC converter. In this research, a topology for an electric vehicle based on an induction motor that integrates
a high voltage gain bidirectional non-isolated DC/DC converter with a three-phase inverter is proposed. This
study compares a bidirectional DC to DC converter inverter system controlled by fuzzy logic (FL), and fractional
order proportional integral derivative (FOPID). The suggested converter runs in discontinuous-current mode
(DCM), with all switches and diodes switching at zero current. It is possible to operate across a wide duty cycle
range while maintaining high output voltage gain, low switching stress, minimal switching losses, and high
efficiency. The proposed converter's size and weight are decreased so as to support a wide range of duty cycle
operations, maintain lower voltage stress on all devices, ensure equal current sharing among inductors, are
simple to control, and require a more compact inductor. The converter also uses a constant input current which
offers a choice for various applications. MATLAB Simulink is used to construct, model, and simulate open loop
system, closed loop FL and FOPID. The results of these simulations are then reported. The investigations show
that FOPID controlled DC-DC converter performed better response
Performance enhancement of sensorless induction motor drive using modified direct torque control techniques for traction application
In recent scenarios, induction motors are used in many different fields due to their small size, advanced technology, and capacity to handle large amounts of power. One of the annoying downsides of conventional AC traction drive systems is the engine's speed and the uncertainty of the ripple content. The goal of the proposed work is to use various control techniques to analyze and enhance the performance of two five-phase induction motors that are supplied in parallel via an inverter. The control techniques are scalar control, six-step voltage type source inverter (VSI), space vector modulation (SVM) based VSI inverter, field-oriented control, model reference adaptive system-based field-oriented control (FOC), direct torque control (DTC), direct torque control -SVM, model reference adaptive system based direct torque control-SVM for traction application. The modified space vector modulation-based induction motor (IM) sensorless drive is realized together with a comparison of several control strategies. It makes use of direct torque control approaches with a model reference adaptive system (MRAS). An IM is designed, and performances are analyzed in high-speed and low-speed regions. Two bogies sets were considered in the closed-loop scheme, tested under parameter variations and in low-speed areas. The simulation result examined the most significant control methods for an IM fed by an inverter for electric traction applications. The performance of the torque in terms of reduced torque ripple in the IM drive is analyzed. The proposed direct torque control technique will reduce torque harmonic ripple by 100 % under the steady-state condition. Under a change in a parameter, the torque harmonic ripple is decreased by 99 %. For the IM drive, the hardware implementation of the advanced control approaches is examined
Households’ Waste Disposal Practices and Its Impact on Health
Waste management has been a worldwide concern today. India being the most populous country the rate of waste generation is also increasing rapidly. The problem of waste management has become a serious issue due to improper disposal of waste. The present study was conducted to examine the existing disposal practices of household waste. An Exploratory research design was used to conduct the present study with 60 respondents. Information on various types of waste, frequency of waste disposal and methods of waste disposal were obtained through the structured interview schedule. It was observed that majority of the respondents complain about the ill effects of improper disposal of solid waste. More than 80 per cent have collectively said that it causes infectious diseases, unpleasant odour and unclean surroundings. Through the study, it was observed that respondents are disposing the household waste by just throwing away outside the house. Burning of waste is also the most common practice followed by the respondents to clean their surroundings. Findings revealed that even though respondents have knowledge on waste management but their practice towards disposal of dry waste is poor. Age and family size were negatively correlated with waste disposal practices while education has a significant positive correlation with waste disposal practices