894 research outputs found
Power Emission Enhancement of Light Emitting Diode by Using InN based Quantum Dot
AbstractThis paper highlights the enhancement of emitted power from light emitting diodes using InN based quantum dot in the active layer of the device structure. We have developed mathematical models and analyzed numerically the temperature dependence of the degradation rate of the device lifetime, the effect of light transmission factor and the operating time on the power emitted from the light emitting diodes. The results obtained by using InN based quantum dot in the active layer of the device have been compared with those obtained by using InP based quantum dot in the active layer of the device. The comparison results reveal that the degradation rate of the device has been reduced and the power emission has been enhanced significantly by using InN based quantum dot in the active layer of the device. It can be then concluded that InN based quantun dot will bring a revolusionary changes in the performance improvement of LEDs in the near future
Independent component analysis for fetal heart rate detection using photosplethysmography
Photoplethysmography (PPG) is an optoelectronic technique
for measuring and recording changes in the volume of body parts.
These changes are associated with each heart beat and acquired by
pulse oximetry. Fetal heart rate (FHR) monitoring using PPG is a
challenging task since the acquired signals present the pattern of both
fetal and maternal hearts. The effect of maternal component, noise
and artifacts on fetal component makes the separation of FHR very
difficult. In this paper, we study the applicability of independent
component analysis (lCA) to FHR detection using PPG. The study
was conducted using emulated signals to mimic the pulsation nature
of both maternal and fetal hearts. The outcome of this experiment
shows encouraging results in terms of the extraction ability oflCA,
which can perform well even when fetal-to-maternal signal-to-noise
ratio (SIY~) drops to -276 dB
Resource productivity and economic performance of producing fish seeds in government and private fanns in Bangladesh
The effect of various factors on spawn and fingerlings production in government and
private farms was measured in this study. Primary data were collected from 45 private
and 11 government farms from 9 selected districts covering major fish seed producing
areas of Bangladesh. Results from Cobb-Douglas production function analysis indicated
that the included variables had some positive impacts on returns from spawn and
fingerlings. No input was found to be over used and increasing returns to scale was
observed. Tabular analysis indicated that higher amount of input use produced higher
level of yield, gross return and net return. The government farms were under utilized.
For increased supply of fish seeds in the country more amount of specified inputs (feed
and fertilizer) should be used for producing spawn and fingerlings especially in
government farms
Fault Identification of In-Service Power Transformer using Depolarization Current Analysis
Preventive diagnostic testing of in-service power transformers require system outage and expert’s knowledge and experiences in interpreting the measurement results. The chemical oil analysis may cause significant variance to measurement results due to the different practices in oil sampling, storage, handling and transportation. Thus, a cost effective measuring technique by means of a simpler method that is able provide an accurate measurement results is highly required. The extended application of Polarization and Depolarization Current (PDC) measurement for characterization of different faults conditions on in-service power transformer has been presented in this paper. The oil sample from in-service power transformers with normal and 3 different faults type conditions were sampled and tested for Dissolved Gases Analysis (DGA) and PDC measurement. The DGA results was used to confirm type of faults inside the transformer while the PDC pattern of oil with normal, partial discharge, overheating and arcing were correlated to the oil sample conditions. The analysis result shows that depolarization current provides significant information to defferenciate fault types in power transformer. Thus this finding provides a new alternative in identifying incipient faults and such knowledge can be used to avoid catastrophic failures of power transformers
Group theoretic methods applied to Burgers’ equation
AbstractIn this study, the group-theoretic methods for calculating the solution of Burgers’ equation with appropriate boundary- and initial-conditions is presented. The application of a one-parameter group reduces the number of independent variables by one, and consequently the governing partial differential equation with the boundary- and initial-conditions to an ordinary differential equation with the appropriate corresponding conditions. The obtained differential equation is solved analytically and the solution obtained in closed form, for a specific choice of boundary condition
Clean Water from Clean Energy: Decentralised Drinking Water Production Using Wind Energy Powered Electrodialysis
Supply of potable water requires energy and unfortunately most of the countries with minimal access to safe drinking water are also poor in terms of access to reliable energy grids. However, many of such regions have access to other sources of water (such as brackish and groundwater) that can be treated for producing drinking water if correct treatment systems are put in place. Moreover, many of the electrically remote areas are rich in terms of renewable energy (RE) resources (such as wind and solar) which can be potentially employed as the main source of energy for powering water purification systems. Therefore, development and implementation of off‐grid RE powered contaminant removal systems, for producing freshwater from available resources (such as brackish and groundwater), can be considered as an effective and potentially sustainable solution for overcoming the drinking water scarcity issue in remote regions of developing countries. This chapter revises the state of the art related to desalination systems using electrodialysis technology powered by wind energy for decentralised water production
Feedforward backpropagation, genetic algorithm approaches for predicting reference evapotranspiration
Water scarcity is a global concern, as the demand for water is increasing tremendously and poor management of water resources will accelerates dramatically the depletion of available water. The precise prediction of evapotranspiration (ET), that consumes almost 100% of the supplied irrigation water, is one of the goals that should be adopted in order to avoid more squandering of water especially in arid and semiarid regions. The capabilities of feedforward backpropagation neural networks (FFBP) in predicting reference evapotranspiration (ET0) are evaluated in this paper in comparison with the empirical FAO Penman-Monteith (P-M) equation, later a model of FFBP+Genetic Algorithm (GA) is implemented for the same evaluation purpose. The study location is the main station in Iraq, namely Baghdad Station. Records of weather variables from the related meteorological station, including monthly mean records of maximum air temperature (Tmax), minimum air temperature (Tmin), sunshine hours (Rn), relative humidity (Rh) and wind speed (U2), from the related meteorological station are used in the prediction of ET0 values. The performance of both simulation models were evaluated using statistical coefficients such as the root of mean squared error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The results of both models are promising, however the hybrid model shows higher efficiency in predicting ET0 and could be recommended for modeling of ET0 in arid and semiarid regions
Digitizing Hydrological Patterns For River Traffic Safety
This paper is intended to assess risk of river transportation due to flow conditions during adverse weather and barrage operation modes. Passenger boat sailing conditions for the mentioned conditions is rarely addressed in the literatures. Safety issue is prevalent as Kuching communities rely on Lower Sarawak River for mobility. The river conditions are represented by means of computer river model, both in 1-D and 2-D approaches. The outputs of model are in the forms of identification of critical stretches exposed to rapid currents, flushing mechanisms, velocity patterns and its associated relationships. Such modelling results provide a tool quantitatively compares the barrage operations and velocity ranges along Lower Sarawak River in graphical and information to support critical safety decisions
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