Adaptive shoot-through duty ratio control methodology of stand-alone quasi Z-source inverter

This paper presents an adaptive shoot-through duty ratio control methodology for a stand-alone three-phase quasi-Z-source inverter (qZSI). In practice, variable active and reactive load powers must be met by a qZSI-based stand-alone system. In this context, existing shoot-through control schemes for qZSI adjust the capacitor voltage or DC-link voltage at a fixed reference value. This causes extra voltage stresses on switches, high distortions, and an operating range reduction of the power inverter under variable load demands. On the contrary, the proposed shoot-through control scheme adjusts the shoot-through duty ratio adaptively based on load voltage feedback to improve performances. In this logic, the controllable shoot-through duty ratio facilitates various improved features in comparison to conventional schemes under load power variations. These features include reduced voltage stress across the switches, reduced distortions, and an extended operating range. The suggested proportional-integral (PI)-based scheme has a single control loop with a single measured quantity, i.e., sensing of load voltage only. The proposed concept has been verified via both simulation and experimental studies

The Zeta (ζ\zeta) Notation for Complex Asymptotes

Time Complexity is an important metric to compare algorithms based on their cardinality. The commonly used, trivial notations to qualify the same are the Big-Oh, Big-Omega, Big-Theta, Small-Oh, and Small-Omega Notations. All of them, consider time a part of the real entity, i.e., Time coincides with the horizontal axis in the argand plane. But what if the Time rather than completely coinciding with the real axis of the argand plane, makes some angle with it? We are trying to focus on the case when the Time Complexity will have both real and imaginary components. For Instance, if $T\left(n\right)=\ n\log{n}$, the existing asymptomatic notations are capable of handling that in real time But, if we come across a problem where,$T\left(n\right)=\ n\log{n}+i\cdot n^2$, where,$i=\sqrt[2]{-1}$, the existing asymptomatic notations will not be able to catch up. To mitigate the same, in this research, we would consider proposing the Zeta Notation ($\zeta$), which would qualify Time in both the Real and Imaginary Axis, as per the Argand Plane

Clinico-mycological study of dermatophytosis in a tertiary care centre in North Eastern India

Background: The dermatophytosis constitutes a group of superficial fungal infections of keratinized tissues, namely, the epidermis, hair, and nails. The present study was undertaken to find out the clinical profile of dermatophytosis and to identify the causative fungal species in the various clinical presentations. Materials & Methods: This was a hospital‐based observational study. One hundred clinically suspected patients attending OPD of M. G. M. Medical College and Lion Seva Kendra Hospital were included in the study. History was taken, general physical and cutaneous examination was done and details of skin lesions noted. Direct microscopy in 10% KOH (40% KOH for nail) and fungal culture on SDA with 0.05% chloramphenicol and 0.5% cycloheximide was done in every case. Chi‐square test and contingency coefficient test were used as significant tests for analysis. Results: In the present study, tinea accounted for 22.68 % of the total Dermatology OPD cases of which male constituted 59 % and 41 % females. The mean age was 38.4 ± 16.98 years. Majority were of age group 21-30 years followed by age group 31-40 years.Out of all the samples 68 cases were KOH positive as compared to 61 cases which were culture positive. Two KOH negative cases were culture positive and 9 culture negative cases came out to be KOH positive. Out of 81 skin scrapping samples 54 were KOH positive and 47 were culture positive, 11 nail clipping samples 8 were KOH as well as culture positive and out of 8 hair pluck samples 6 were KOH as well as culture positive.In 61 culture positive cases there were 7 non-dermatophytic growth which included 4 aspergillus spp. and 3 candida spp. Conclusion: Dermatophytosis is one of the most common if not the commonest dermatological condition we come across the Dermatology OPD. It most commonly affects the young age group rather than extremes of age

Unified View of Damage leaves Planimetry & Analysis Using Digital Images Processing Techniques

The detection of leaf diseases in plants generally involves visual observation of patterns appearing on the leaf surface. However, there are many diseases that are distinguished based on very subtle changes in these visually observable patterns. This paper attempts to identify plant leaf diseases using image processing techniques. The focus of this study is on the detection of citrus leaf canker disease. Canker is a bacterial infection of leaves. Symptoms of citrus cankers include brown spots on the leaves, often with a watery or oily appearance. The spots (called lesions in botany) are usually yellow. It is surrounded by a halo of the leaves and is found on both the top and bottom of the leaf. This paper describes various methods that have been used to detect citrus leaf canker disease. The methods used are histogram comparison and k-means clustering. Using these methods, citrus canker development was detected based on histograms generated based on leaf patterns. The results thus obtained can be used, after consultation with experts in the field of agriculture, to identify suitable treatments for the processes used

Power Consumption Analysis, Measurement, Management, and Issues:A State-of-the-Art Review of Smartphone Battery and Energy Usage

The advancement and popularity of smartphones have made it an essential and all-purpose device. But lack of advancement in battery technology has held back its optimum potential. Therefore, considering its scarcity, optimal use and efficient management of energy are crucial in a smartphone. For that, a fair understanding of a smartphone's energy consumption factors is necessary for both users and device manufacturers, along with other stakeholders in the smartphone ecosystem. It is important to assess how much of the device's energy is consumed by which components and under what circumstances. This paper provides a generalized, but detailed analysis of the power consumption causes (internal and external) of a smartphone and also offers suggestive measures to minimize the consumption for each factor. The main contribution of this paper is four comprehensive literature reviews on: 1) smartphone's power consumption assessment and estimation (including power consumption analysis and modelling); 2) power consumption management for smartphones (including energy-saving methods and techniques); 3) state-of-the-art of the research and commercial developments of smartphone batteries (including alternative power sources); and 4) mitigating the hazardous issues of smartphones' batteries (with a details explanation of the issues). The research works are further subcategorized based on different research and solution approaches. A good number of recent empirical research works are considered for this comprehensive review, and each of them is succinctly analysed and discussed

A comparative study on the performance and emissions from a CI engine fuelled with water emulsified diesel prepared by mechanical homogenization and ultrasonic dispersion method

In this study, the authors have tried to compare the stability behaviour of water emulsified diesel (WED) prepared by mechanical homogenizer and ultrasonicator. Both types of emulsion have been prepared by adding 10% water and 2% surfactant mixture of Span 80 and Tween 80. The emulsion prepared by ultrasonicator (WED U) shows higher stability than that prepared by mechanical homogenizer (WEDM). Two important physical properties namely, viscosity and density of the prepared WEDs have been measured and compared to those with base diesel. Experimental investigations have also been carried out in a diesel engine using neat diesel as well as WEDs to compare the effect of mechanical homogenization and ultrasonication methods on combustion, performance and emission characteristics of the engine. The emulsion prepared using ultrasonicator shows improved combustion characteristics due to smaller size and more homogeneous distribution of the water particles. Higher brake thermal efficiency and lower brake specific fuel consumption are observed using WEDU. Both the combustion and the performance behaviours of the engine using emulsions prepared by ultrasonicator show improved characteristics. But, the results are not much encouraging of WEDM. NOx and smoke emissions are noted to be significantly reduced for both types of prepared emulsions. However, the difference in CO emission at full load condition is found to be marginal

Effect of fuel injection pressure on the performances of a CI engine using water-emulsified diesel (WED) as a fuel

Abstract Background The choice of energy sources is essential for sustainable development to combat different environmental issues caused by the consumption of fossil fuels. Though diesel engines are considered more efficient and reliable than other internal combustion engines, they emit different harmful pollutants which are detrimental to human health and the environment. Researchers are trying to find suitable alternative fuels for diesel engines with lower pollutant emissions and without much compromise in the efficiency of the engine. In this regard, water-emulsified diesel (WED) may be considered to be one of the most suitable alternative fuels. It is expected that the entire world will use electric vehicles in the long term. However, the complete replacement of IC engines in the near future is not feasible. In fact, different European countries have targeted to ban the use of diesel engine cars before the middle of the twenty-first century. Prior to that date, hybrid vehicles will be more popular and diesel engines will continue to play an important role. Hence, research involving improvements in diesel-operated IC engines is still relevant. Methods An experimental investigation was carried out using WED containing 10% water by volume as a fuel in a diesel engine at four different fuel injection pressures. The WED was prepared using an ultrasonicator. Results With the increase of injection pressure, peak net heat release rate and in-cylinder pressure are found to have increased. Brake thermal efficiency is also found to have improved at higher injection pressure. The maximum efficiency was recorded when a WED at 210 bar of injection pressure is used, and it is about 3.3% higher than the maximum efficiency achieved when using normal diesel at the same pressure of fuel injection. At a higher load, neat brake-specific fuel consumption is found to be less compared to neat diesel, when only the amount of diesel contained in the emulsion as a fuel is considered. Maximum reduction in both NOx and smoke emission by using WED is recorded at 210 bar, and the average reductions are determined to be 32.6% and 51.9%, respectively. Conclusions WED can be used as an alternative fuel for existing diesel engines without any retrofitting and with significant reduction in the emissions of pollutants compared to normal diesel fuel. It can also be concluded that at higher injection pressure, the combustion, performance and emission characteristics of compression ignition engines are improved when using emulsified diesel

Metal impregnated silica-carbon materials from rice husk: a versatile sorbent for toxic organics and inorganics in water and air

Carbon bearing materials derived from rice husk (RH) have long been recognized as sorbents for diverse chemicals both organic and inorganic. This work presents an overview of studies demonstrating a single step process of carbonization of chemically pretreated RH to produce metal impregnated silica-carbon char designated as silicarbon materials that can be utilized in sorbing out water-borne organic and inorganic hazardous substances (such as phenol, hexavalent chromium, fluoride, and arsenic) and air-borne volatile organic chemicals (such as acetone, chloroform, benzene, and pyridine). The metal-impregnated silicarbon solids derived from RH appear to constitute renewable, low-cost, user-friendly, and efficient materials for control systems for indoor air contamination and for industrial as well as non-industrial hazardous aqueous pollution