Bipolar DC output fed grounded DC-AC converter for photovoltaic application

Introduction. In recent years the usage of electricity has increased tremendously as the electrical needs and loads got increased. Hence the researchers focused on the electricity generation from renewable sources in order to promote sustainable green environment. Owing to the lesser cost and more reliable high efficiency system with reduced use of equipments became prominent for the grid connected photovoltaic single phase systems. The novelty of this proposed converters are to reduce total power loss and to analyze the performance of the converter under various modulation index and to have lesser harmonics using sinusoidal pulse width modulation technique for both T-type and F-type inverter. Interest of the work is to merge two DC-DC converters which have same output voltage in order to have transformer less utilization of power. This has given pathway to develop a new DC-DC converter network by merging the common input nodes of CUK and SEPIC converter. Purpose. This similar structure of both converters made it easy to combine the input stages of and to get bipolar output. Methods. Here we can get bipolar output without the utilization of transformer which minimizes the overall size of the proposed system. In this paper, a combined CUK-SEPIC based grid connected transformerless inverter for photovoltaic application is suggested. Results. The suggested converter is simulated using MATLAB and the results were discussed. Further the circuit is extended with a 1 kW F-type inverter to demonstrate grid connection of the converter. Practical value. This converter can be implemented for photovoltaic applications for obtaining the bipolar DC output from the DC source.Вступ. В останні роки використання електроенергії значно зросло, оскільки потреби в електроенергії та навантаження збільшились. Тому дослідники зосередилися на виробництві електроенергії з відновлюваних джерел, щоб сприяти стійкому зеленому середовищу. Через меншу вартість та більш надійну високоефективну систему зі зменшеним використанням обладнання набули популярності фотоелектричні однофазні системи, підключені до мережі. Новизна пропонованих перетворювачів полягає у зниженні загальних втрат потужності та аналізі характеристик перетворювача при різних індексах модуляції, а також у зменшенні гармонік з використанням методу широтно-імпульсної модуляції синусоїдального типу для інверторів як Т-типу, так і F-типу. Інтерес роботи полягає в об'єднанні двох перетворювачів постійного струму з однаковою вихідною напругою, щоб мати менше використання потужності трансформатора. Це дозволило розробити нову мережу перетворювачів постійного струму шляхом об'єднання загальних вхідних вузлів перетворювача CUK та SEPIC. Мета. Подібна структура обох перетворювачів дозволила легко поєднати вхідні каскади та отримати біполярний вихідний сигнал. Методи. Тут ми можемо отримати біполярний вихід без використання трансформатора, що мінімізує загальний розмір пропонованої системи. У цій статті пропонується комбінований безтрансформаторний інвертор на основі CUK-SEPIC, підключений до мережі, для фотоелектричних застосувань. Результати. Пропонований перетворювач моделюється за допомогою MATLAB, результати обговорюються. Далі схема розширена інвертором F-типу потужністю 1 кВт, щоб продемонструвати підключення перетворювача до мережі. Практична цінність. Цей перетворювач може бути реалізований для фотоелектричних застосувань для отримання біполярного виходу постійного струму джерела постійного струму

Bipolar DC output fed grounded DC-AC converter for photovoltaic application

Introduction. In recent years the usage of electricity has increased tremendously as the electrical needs and loads got increased. Hence the researchers focused on the electricity generation from renewable sources in order to promote sustainable green environment. Owing to the lesser cost and more reliable high efficiency system with reduced use of equipments became prominent for the grid connected photovoltaic single phase systems. The novelty of this proposed converters are to reduce total power loss and to analyze the performance of the converter under various modulation index and to have lesser harmonics using sinusoidal pulse width modulation technique for both T-type and F-type inverter. Interest of the work is to merge two DC-DC converters which have same output voltage in order to have transformer less utilization of power. This has given pathway to develop a new DC-DC converter network by merging the common input nodes of CUK and SEPIC converter. Purpose. This similar structure of both converters made it easy to combine the input stages of and to get bipolar output. Methods. Here we can get bipolar output without the utilization of transformer which minimizes the overall size of the proposed system. In this paper, a combined CUK-SEPIC based grid connected transformerless inverter for photovoltaic application is suggested. Results. The suggested converter is simulated using MATLAB and the results were discussed. Further the circuit is extended with a 1 kW F-type inverter to demonstrate grid connection of the converter. Practical value. This converter can be implemented for photovoltaic applications for obtaining the bipolar DC output from the DC source.Вступ. В останні роки використання електроенергії значно зросло, оскільки потреби в електроенергії та навантаження збільшились. Тому дослідники зосередилися на виробництві електроенергії з відновлюваних джерел, щоб сприяти стійкому зеленому середовищу. Через меншу вартість та більш надійну високоефективну систему зі зменшеним використанням обладнання набули популярності фотоелектричні однофазні системи, підключені до мережі. Новизна пропонованих перетворювачів полягає у зниженні загальних втрат потужності та аналізі характеристик перетворювача при різних індексах модуляції, а також у зменшенні гармонік з використанням методу широтно-імпульсної модуляції синусоїдального типу для інверторів як Т-типу, так і F-типу. Інтерес роботи полягає в об'єднанні двох перетворювачів постійного струму з однаковою вихідною напругою, щоб мати менше використання потужності трансформатора. Це дозволило розробити нову мережу перетворювачів постійного струму шляхом об'єднання загальних вхідних вузлів перетворювача CUK та SEPIC. Мета. Подібна структура обох перетворювачів дозволила легко поєднати вхідні каскади та отримати біполярний вихідний сигнал. Методи. Тут ми можемо отримати біполярний вихід без використання трансформатора, що мінімізує загальний розмір пропонованої системи. У цій статті пропонується комбінований безтрансформаторний інвертор на основі CUK-SEPIC, підключений до мережі, для фотоелектричних застосувань. Результати. Пропонований перетворювач моделюється за допомогою MATLAB, результати обговорюються. Далі схема розширена інвертором F-типу потужністю 1 кВт, щоб продемонструвати підключення перетворювача до мережі. Практична цінність. Цей перетворювач може бути реалізований для фотоелектричних застосувань для отримання біполярного виходу постійного струму джерела постійного струму

Maternal and Fetal Outcome of pyrexia in pregnancy beyond 28 weeks of gestation: A Prospective Cohort study

AIMS AND OBJECTIVES : Fever in pregnancy is a common clinical problem which increases risk of morbidity of the mother and fetus. We studied the variable medical complications of pregnant women suffering from fever and the possible fetal complications beyond 28 weeks of gestation. We also studied the etiology and prevalence of pyrexia in pregnancy beyond 28 weeks of gestation. MATERIALS AND METHODS : A prospective cohort study was conducted in 180 antenatal women, 90 patients exposed to fever (temperature >= 38*c and 90 patients not exposed to fever beyond 28 weeks. Necessary investigations to detect the underlying cause were performed. Maternal complications and adverse perinatal outcomes in terms of preterm delivery, perinatal death, low birth weight (LBW) and low Apgar score at 5 minutes after birth were recorded and compared between the cohort and the control group. RESULTS : The etiology and the prevalence of fever among the study group was enlisted. Urinary tract infection was the most common cause of fever in our study (32.2%). Maternal complications due to pyrexia were more common in the study group when compared to control group. P value is 0.000 which is statistically significant. The adverse fetal outcome were low birth weight, neonatal sepsis, low APGAR score at 5 minutes of birth, preterm labour, intra uterine growth retardation,perinatal death were more common in the study group when compared to the control group. Of these neonatal sepsis and low APGAR score at birth was more sensitive and specific. P value is 0.000 which is statistically significant. There were 2 perinatal deaths. CONCLUSION : Our study depicts that a wide range of maternal medical complications as well as fetal and neonatal complications occur due to pyrexia in pregnancy from various etiologies

Investigation of efficient multilevel inverter for photovoltaic energy system and electric vehicle applications

Introduction. This research presents a simple single-phase pulse-width modulated 7-level inverter topology for renewable system which allows home-grid applications with electric vehicle charging. Although multilevel inverters have appealing qualities, their vast range of application is limited by the use of more switches in the traditional arrangement. As a result, a novel symmetrical 7-level inverter is proposed, which has the fewest number of unidirectional switches with gate circuits, providing the lowest switching losses, conduction losses, total harmonic distortion and higher efficiency than conventional topology. The novelty of the proposed work consists of a novel modular inverter structure for photovoltaic energy system and electric vehicle applications with fewer numbers of switches and compact in size. Purpose. The proposed system aims to reduce switch count, overall harmonic distortions, and power loss. There are no passive filters required, and the constituted optimizes power quality by producing distortion-free sinusoidal output voltage as the level count increases while reducing power losses. Methods. The proposed topology is implemented with MATLAB/Simulink, using gating pulses and various pulse-width modulation methodologies. Moreover, the proposed model also has been validated and compared to the hardware system. Results. Total harmonic distortion, number of power switches, output voltage, current, power losses and number of DC sources are investigated with conventional topology. Practical value. The proposed topology has proven to be extremely beneficial for implementing photovoltaic-based stand-alone multilevel inverter and electric vehicle charging applications.Вступ. У цьому дослідженні представлена топологія простого семирівневого однофазного інвертора з широтно-імпульсною модуляцією для системи з відновлюваними джерелами енергії, яка дозволяє використовувати домашню мережу з зарядкою електромобілів. Хоча багаторівневі інвертори мають привабливі характеристики, широкий спектр їх застосування обмежений використанням більшої кількості перемикачів у традиційній схемі. В результаті запропонований новий симетричний 7-рівневий інвертор, який має найменшу кількість односпрямованих ключів із затворними ланцюгами, забезпечує найменші комутаційні втрати, втрати на провідність, сумарні гармонічні спотворення та вищий ККД, ніж традиційна топологія. Новизна запропонованої роботи полягає у новій модульній структурі інвертора для фотоелектричних енергетичних систем та використання для електромобілів з меншою кількістю перемикачів та компактними розмірами. Мета. Пропонована система спрямована на зменшення кількості перемикань, загальних гармонічних спотворень та втрат потужності. Пасивні фільтри не потрібні, а складова частина оптимізує якість електроенергії, створюючи синусоїдальну вихідну напругу без спотворень зі збільшенням кількості рівнів при одночасному зниженні втрат потужності. Методи. Запропонована топологія реалізована за допомогою MATLAB/Simulink з використанням стробуючих імпульсів та різних методологій широтно-імпульсної модуляції. Крім того, запропонована модель також була перевірена та порівняна з апаратною системою. Результати. Загальні гармонічні спотворення, кількість силових ключів, вихідна напруга, струм, втрати потужності та кількість джерел постійного струму досліджуються за допомогою традиційної топології. Практична цінність. Запропонована топологія виявилася надзвичайно корисною для реалізації автономних багаторівневих інверторів на основі фотоелектричних систем та застосування для заряджання електромобілів

A study on chronic autoimmune urticaria and efficacy of autologous serum therapy.

INTRODUCTION ; Chemical peeling is a technique used to improve the appearance of the skin. A chemical solution is applied to the skin, which causes it to separate, peel off, and allows new skin to regenerate. The new skin is smoother and less wrinkled than the old skin, and may also be more even in color Dermatologists have used various peeling agents for decades and are experts in performing all types of this chemical surgery. This concept dates back to Roman times. Superficial and medium depth skin peeling with trichloroacetic acid has been a well documented therapy in United states since atleast 1960. Dr. Baker and Gordon pioneered chemical peeling with phenol in the year 1961. Chemical peeling one of the latest treatments available for the about disease in modern era. Superficial and medium depth skin peels can create dramatic improvement in the skin but the results were not long lasting as those with phenol peels. The use of retinoic acid alpha hydroxyl acids, broad-spectrum sunscreens and skin bleaches as part of a post-peel maintenance programme has allowed patients maintain the improvement in skin for far longer. Microdermarasion is a non- chemical, non- invasive modality for treating superficial skin blemishes resulting from trauma, aging, prolonged exposure to skin or mild acne. Microdermabrasion has been used successfully since atleast 1992 to treat acne, fine lines and wrinkles, unwanted pigmentation and other superficial skin damage. Even though various modalities of treatment are available for acne, it still pores a therapeutic problem to the attending dermatologist. The advent of new and potent topical therapeutic agents, chemical peeling and dermabrasion has resulted in significant improvement for us to treat many forms of acne. This study attempts to find the therapeutic response to various chemical peels like salicylic and glycolic acid on acne along with microdermabrasion. AIM OF THE STUDY ; The aim of the study is to compare the efficacy of glycolic acid and salicylic acid peels in the treatment of acne vulgaris with each other and as combination with microdermabrasion. The agents compared were the following: Glycolic acid alone, Glycolic acid and microdermabrasion, Salicylic acid alone, Salicylic acid and microdermabrasion. CONCLUSION : 1. Patients in whom chemical peeling was followed with microdermabrasion showed better results compared to patients in whom chemical peeling alone was done. 2. If chemical peeling is done alone or combined with microdermabrasion, salicylic acid peel is superior to glycolic acid peel in the treatment of acne. 3. Though salicylic acid peel with microdermabrasion showed better results, the improvement rate was more with glycolic acid with microdermabrasion than salicylic acid peel with microdermabrasion. 4. Hyper-pigmentation is more common side effect with salicylic acid peel, while erosion and burning sensation were more with glycolic acid peel. 5. Though the side effects observed with these peels reduced by itself, application of emollients, mild steroids and sun screeners hastened the recovery

Vasa previa: a case report

Vasa previa is defined as a condition where fetal vessels traverse the membranes in the lower segment below the presenting part unsupported by placental tissue or umbilical cord. Rupture of the membranes leads to fetal exsanguinations and even neonatal death. The etiology is uncertain, but risk factors include bilobed or succenturiate lobed placenta, velamentous insertion of cord, placenta previa, pregnancies resulting from In vitro fertilization (IVF) and multiple pregnancies. We report here a case of 24 year old woman, G3A2 at 34 weeks of gestation and history of 2 previous spontaneous abortions with vasa previa which was successfully managed. Prenatal sonographic diagnosis has the potential to improve or prevent the poor obstetric and neonatal outcome associated with it

Obstetric outcome of antenatal mother with history of spontaneous abortion attending a tertiary care hospital in Puducherry

Background: The pregnancy time is critical for both the mother’s and the baby’s health. The most common unfavourable pregnancy outcome is spontaneous abortion. Spontaneous pregnancy loss is a surprisingly common event, with roughly 15% of all clinically diagnosed pregnancies ending in pregnancy failure. Couples who suffer from frequent miscarriages may find it difficult to cope physically and emotionally. This study was planned to evaluate the association of preterm delivery, low birth weight, IUGR, recurrence of abortion, still birth, IUD, PROM, or any other adverse outcome in patients with history of previous spontaneous abortions. Objectives were to look for association between previous spontaneous abortion and preterm delivery, low birth weight, IUGR, recurrence of abortion, stillbirth, IUD, PROM and other complications in subsequent pregnancies. Methods: This was a prospective observational study done with 150 samples. The information such as demographic data of the antenatal women, clinical history, past obstetrics history, clinical examination, laboratory investigations and outcome of present pregnancy were collected and evaluated. Results: Maternal complications such as UTI (4.6%), Infection and fever (5.3%), PROM (2.7%), PPH (4%), hyperemesis 4%, PPROM 2.7% were observed. In study population, 60% of the foetus were in cephalic position, 19% in breech presentation and 21% in shoulder presentation.  29% of the women had preterm delivery, 34% were delivered by LSCS and 6% had spontaneous abortions. Low birth weight babies delivered in 25% cases. Foetal distress was observed in 15%, FGR in 9%, still birth in 3% and IUD in 1%. Conclusions: Women with previous spontaneous abortion are associated with a higher incidence of preterm delivery, cesarean section rate, neonatal low birth weight, fetal distress and high possibility of infection. Therefore, patients with previous spontaneous miscarriage represent a high-risk population for obstetric complication and close surveillance during the antenatal period is required

IoT Enabled Smart Fertilization and Irrigation Aid for Agricultural Purposes

Soil is of great importance to agriculture, especially the moisture and nutrients in the soil are the essential ingredients for growing plants and crops. Therefore, benefits and importance of a soil moisture and nutrient monitoring system in modern agriculture and gardening is undeniable. It can also be an interesting feature of an intelligent home or smart agriculture system using the internet of things (IoT) technology. This paper presents an IoT application in Arduino platform aiming to monitor the change in soil moisture and Nitrogen (N), Phosphorus (P), Potassium (K) (NPK) value for an indoor plant using moisture sensors and optical transducers. Other functionalities and important features of this prototype include online data display infographic as user feedback, level-based nutrient classification for enabling proper type of fertilizer selection, hardware and e-mail notification of moisture and nutrients' easily accessible and user-friendly smartphone app

Proactive Indoor Air Quality Monitoring System

In recent times indoor air quality has attracted the attention of policy makers and researchers similar to that of external air pollution. The indoor environments are confined and closed compared to external environments providing less opportunity for the pollutants to dilute. Our everyday devices emit various solids and gases into the environment during their operation. These emissions contain many substances that are harmful to human health, when exposed to them for a prolonged period of time. Here we propose an air quality monitoring system that allows us to monitor and check live air quality in particular areas through IOT. The System uses air sensors to sense presence of harmful gases/compounds in the air and constantly transmit this data to microcontroller PIC16F877A. The sensors interact with microcontroller which processes this data and transmits it over internet. The gas levels can be viewed through a webpage from anywhere in the world. This allows authorities to monitor air pollution in different areas and take action against it

Low-altitude, high-resolution aerial imaging systems for row and field crop phenotyping: A review

Global plant genetics research efforts have focused on developing high yielding, stress tolerant, and disease resistant row and field crop varieties that are more efficient in their use of agronomic inputs (water, nutrients, pesticides, etc.). Until recently, a key bottleneck in such research was the lack of high-throughput sensing technologies for effective and rapid evaluation of expressed phenotypes under field conditions for holistic data-driven decision making and variety selection. This review focuses on technological aspects of integrating unmanned aerial vehicles with imaging systems to enhance field phenotyping capabilities. The state-of-the-art of unmanned aerial vehicle technology for various applications including crop emergence, vigor, and characterization of yield potential of row and field crops has been reviewed. The potential of using aerial imaging to evaluate resistance/susceptibility to biotic and abiotic stress for crop breeding and precision production management has been discussed along with future perspectives and developments.Keywords: High-throughput field phenomics, Aerial imaging, Crop breeding, Data minin