Study of Capacitor & Diode Aging effects on Output Ripple in Voltage Regulators and Prognostic Detection of Failure

Objectives: To design and simulate a buck converter and detector circuit which can prognostically indicate the power supply failure. Failure of Aluminium Electrolytic Capacitor (AEC) is considered as the parameter causing the power supply failure. To analyse variation of output ripple voltage due to possible changes in the Equivalent Series Resistance (ESR) and effective capacitance of the capacitor and design a detector to detect the failure of power supply prognostically.Methods:  A DC-DC buck converter in SMPS topology is designed by assuming an input voltage of 12V with 3 volts possible fluctuations and an output voltage of 3.3 volts is desired. Simulation is carried out to measure the variation in output ripple voltage caused due to aging of electrolytic capacitor using TINA by Texas Instruments. A detector is also designed to compare the ripple voltage and a predefined threshold voltage so as to indicate the possible failure of Switched Mode Power Supply (SMPS) well in advance by monitoring the output ripple increase.Novelty:    Having a fault tolerant power supply is very important in safety critical applications. Here by monitoring the output ripple variation, the degradation of AEC is predicted by calculating the ESR and capacitance variation. This simple yet effective prognostic detection will support in the design of fault tolerant power supplies.Highlight: It is found that, the ripple at the output increases with aging of the electrolytic capacitor, as with time the equivalent capacitance decreases and Equivalent Series Resistance (ESR) of the capacitor increases. The designed detector output is found to prognostically indicate the failure of SMPS

Investigation on the Flexural Behaviour of Steel Cold Formed Built up Sections

For the past few decades, substantial progress has been made in material properties and construction methodology, which demands in need of development of stronger and lighter members in structural steel applications. The demands of increase in strength and reduction in weight of sections leads to development of structures which are slender and also stability plays a major role in design. The main goal of this study is to develop and investigate the performance of build-up steel I beam sections with corrugated webs. This study focuses on analysis of flexural behaviour and failure modes of plain web, rectangular, trapezoidal web and triangular web in beams by experimental investigations using three point load test and analytical investigations using ANSYS software. From experimental and analytical analysis, triangular corrugated web beam perform better compared to all section. The experimental results obtained are more similar to analytical results obtained by ANSYS software with only slight deviations. The failure modes in both experimental investigation and analytical analysis are similar

A Study on the Great Saphenous Vein including it’s Surgical and Radiological implications.

Great saphenous vein, the vessel of surgical significance, has been studied in detail by dissection and radiological methods. The formation, length and diameter of Great saphenous vein, its level of termination, drainage pattern, its relation with adjacent important structures in detail have been observed and co-related with the findings of already existing studies. The following conclusions are derived from these parameters. In most of the cases the formation of Great saphenous vein was by the union of medial end of dorsal venous arch with medial marginal vein. The mean total length of the Great saphenous vein is 69.08 cm. The average diameter of Great saphenous vein in thigh is 0.29 cm and that in the leg is 0.38 cm. The sapheno-femoral junction on an average was 2.9 cm from the midpoint of inguinal ligament. In most cases, the sapheno-femoral junction was located 3 to 5 cm from pubic tubercle. The average distance from anterior superior iliac spine to saphenofemoral junction is 10.22 cm. High proportion of cases display the drainage pattern with superficial circumflex iliac vein, superficial epigastric vein and lateral accessory saphenous vein forming a common trunk and terminating at fossa ovalis. In 1/3 of instances, the superficial external pudendal vein drains directly into Great saphenous vein. External pudendal artery passed anterior to termination of Great saphenous vein in significant proportion of cases. Most commonly the Great saphenous vein and the saphenous nerve came close few cm below the knee, after which they were in separable. Average no of perforating veins in the thigh is 1.14. Average no of valves in the Great saphenous vein is 8.2. In 6 foetal specimens, the sapheno femoral junction is found to be on an average 2.78 cm from the anterior superior iliac spine, 0.96 cm from pubic tubercle, 0.68 cm from mid point of inguinal ligament Based on this study, I hereby conclude that Great saphenous vein has complex variations in length, drainage pattern and its relationship with external pudendal artery and saphenous nerve. Surgery for varicose veins and saphenous vein grafting require a thorough knowledge of variations in Great saphenous vein. Hence this study will be of use to surgeons

Comparison of Salbutamol Administration by Metered- Dose Inhaler and Spacer with Nebuliser in Adults with Acute Asthma

INTRODUCTION: In the modern era, Bronchial asthma is a disease that is becoming a major health issue in many developing countries. Increased urbanisation may have modified the traditionally low incidence of bronchial asthma in the third world. Depressed socioeconomic conditions may supersede exposure to traffic-related pollution as a factor associated with asthma hospitalization. Although the incidence of new cases of asthma has decreased in recent years, the prevalence of asthma morbidity continues to be a significant clinical and public health issue. The measures of morbidity include the need for urgent medical care and high-dose asthma medications due to uncontrolled asthma symptoms. The word asthma means “panting” or “breathing hard”, it is derived from greek word “aazein”. Asthma is more a clinical diagnosis than a laboratory diagnosis. Bronchial asthma and the resulting spasm was first described by Greek physician Hippocrates in 460-357 BC. That obstruction to bronchial airways lead to symptoms of asthma was put forth by Greco-Roman physician Galen in 130-201 BC. The occurrence of symptoms does not simply mean constriction of airways, it indicates an underlying inflammatory process which occurs as a result of hyperresponsiveness of airways triggered by an allergen. This was discovered by asthma researchers in 1960. AIM AND OBJECTIVES: To analyse the efficacy of salbutamol administered by a nebuliser compared to metered- dose inhaler and spacer in adults with acute Asthma. MATERIALS AND METHODS: In-patients of medical ward in GRH who have clinical features suggestive of bronchial asthma above 13 years of age were prospectively enrolled after informed consent. The diagnosis was based on Pulmonary function tests showing decrease in expiratory flow rates : • Reduction in forced expiratory volume over 1 sec (FEV1) and a proportionally smaller reduction in the forced vital capacity (FVC) and decreased FEV1/FVC ratio (generally 20. • Reversibility test as determined by increase in Peak Expiratory Flow Rate (PEFR) more than twenty percent ; and more than twelve percent or 200-mL increase in Forced Expiratory Volume in 1 second115 minutes after an inhaled short-acting Beta2-agonist. Exclusion Criteria: 1. Patients <13 yrs age. 2. Patients with acute respiratory tract infections, COPD and restrictive lung disease. 3. Patients with heart failure, renal failure and hepatic failure Blood samples were collected for estimation of Blood urea, Serum creatinine and Liver function tests. ECG, ECHO, X RAY CHEST PA view were taken. METHODS: Fifty two patients with acute asthma in the medical ward of Government Rajaji Hospital Madurai were enrolled in the study. All the fifty two patients in the study fulfilled the criteria of American Thoracic Society. Patients above the age of thirteen years with Peak Expiratory flow rates, Forced Expiratory Volume in 1 second below fifty percent of predicted value were eligible for the study. All the patients were on regular treatment with bronchodilators and steroids. A total of 52 patients with acute Bronchial asthma who received salbutamol therapy participated in the study. The patients were divided into 2 groups: 26 (50%) patients in the MDI-Spacer group and 26 (50%) patients in the Nebuliser group. The baseline characteristics of over all cohort were expressed in percentage. Age distribution was 17.3% (40yrs) as shown in Table 1.Sex distribution was males (63.4%) and females( 36.6%) as shown in Table 2. Duration of illness was 19.2% (10yrs), 50% (11-20 yrs), 25% (21-30yrs) and 5.8% (>30yrs) as shown in Table 3. Table 4. shows 75% of patients with seasonal variation and 25% with no seasonal variation. Diurnal variation was demonstrated in 76.9% of patients but not in the rest 23.1%, as illustrated in Table 5. As per Table 6, a positive history of allergy is seen in 80.8% and is negative in 19.2%. As shown in Table 7, 59.6% of patients have a positive family history and 40.4% do not. 26.9% of patients had a history of smoking and 73.1% were non smokers (Table 8). The frequency of illness was 38.5% (daily), 21.1% (2/ week) as depicted. CONCLUSION: 1. Base line characters were not comparable in the study. The patients were equally divided into two groups for better comparison. 2. PEFR improvement was significant at 30 mts and at end of treatment with the MDI-Spacer group than the nebulised group. 3. FEV1 improvement was also significant at 30 mts and at end of treatment with the MDI-Spacer group than the nebulised group. 4. FVC improvement was also significant at 30 mts and at end of treatment with the MDI-Spacer group than the nebulised group. 5. For oxygen saturation, the magnitude of improvement was significant at 30 mts in the spacer group, but at the end of treatment the improvements were similar in both the groups. 6. Heart rate and respiratory rate improvement was present in both groups and were similar in both at 30 mts and at the end of treatment. 7. Clinical improvement was achieved even at a lower dosage in the MDI-spacer group compared to nebuliser group. Salbutamol administration by metered dose inhaler and spacer is as efficacious as nebuliser in adults with acute asthma. Now-a-days Metered Dose Inhaler and Spacer is the best alternative to nebuliser in acute asthma

Analysis of cytology of germ cell tumors with histopathological and serum tumor marker correlation: a tertiary care centre experience

Background: Germ cell tumors are found primarily in children and young adults usually arising from gonads and rarely from extragonadal sites like mediastinum, retroperitoneum, pineal gland and sacrococcygeal region. Involvement of lymphnodes or bodycavities (pleural/peritoneal cavity) is usually associated with metastatic disease.Methods: This is a retrospective analysis of 96 cases of germ cell tumor for which a primary diagnosis of germ cell tumor was given by cytology from primary and metastatic sites. The study period is from January 1993- December 2013. Pap stained and Romanowsky stained smears and cell block sections (10cases) were studied. Serum tumor markers (LDH, BetaHCG and AFP) were correlated in all cases along with histopathology in available cases.Results: Among 96 cases 34 were diagnosed as seminoma/dysgerminoma,10 as embryonal carcinoma,9 as yolk sac tumor,6 as teratoma and 2 as mixed germ ell tumor. In 25 cases the cytology report was suggestive of germ cell tumor and in 10 cases malignant cells favouring germ cell tumor. Among the 10 cases the serum markers were high in six of the cases and the clinician after discussing with the pathologist treated them as germ cell tumors. 47 cases had histopathology and it correlated with cytology except in 14 cases which showed no residual neoplasm after chemotherapy. 15 cases expired immediately after the diagnosis or during the course of treatment 12cases were lost to follow up. Rest of the cases have completed the treatment. In our study the serum tumor markers showed a sensitivity of 92.75% and positive predictive value was 71.11%.Conclusions: The study highlights the importance of picking up the diagnosis of germ cell tumors by fine needle aspiration cytology so that patient can get an early diagnosis, effective treatment and a multidisciplinary approach is essential in diagnosing a difficult case of germ cell tumor. Previous history, radiology, clinical features and serum tumor markers all aid in the cytological diagnosis of germ cell tumor

Pole harvesting - A skillful operation in oil palm fresh fruit bunch (FFB) harvest

The study demonstrates the importance of skilled pole harvester (PH). Skill in pole harvesting ultimately reduces the human drudgery, time and cost involved in rope and cutlass harvest (RCH) while harvesting oil palm fresh fruit bunches (FFBs). Comparative cumulative harvesting activities in FFB harvest apparently showed that average number of strokes for frond(s) and FFB harvest by skilled PH (8.6) were less than unskilled PH (22.0). The slashing time required to harvest FFB was less in case of skilled PH (2.1 min) compared with RCH (3.2 min.) and unskilled PH (17.8 min.) which eventually is reflected in total slashing and harvesting time for 1 MT FFBs. The difficulty experienced by unskilled PH was likely to be more than RCH and skilled PH method of harvest

Employee Empowerment

The work done by the human resource in healthcare are the key to bringing about patient healing. As the tasks that each of the different human resource healthcare professionals have to do is quite enormous and varied and differs from patient to patient depending upon their unique needs it is also equally challenging to train the staff. The concept of employee empowerment is therefore extremely critical for staff to do what requires to be done for patients in a timely manner keeping the best interest of the patient in the mind. This article takes a thorough look at this concept as well as how it is measured. Its application is also discussed taking the example of the Aravind Eye Hospital

Octopus arms exhibit exceptional flexibility

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kennedy, E. B. L., Buresch, K. C., Boinapally, P., & Hanlon, R. T. Octopus arms exhibit exceptional flexibility. Scientific Reports, 10(1), (2020): 20872. doi:10.1038/s41598-020-77873-7.The octopus arm is often referred to as one of the most flexible limbs in nature, yet this assumption requires detailed inspection given that this has not been measured comprehensively for all portions of each arm. We investigated the diversity of arm deformations in Octopus bimaculoides with a frame-by-frame observational analysis of laboratory video footage in which animals were challenged with different tasks. Diverse movements in these hydrostatic arms are produced by some combination of four basic deformations: bending (orally, aborally; inward, outward), torsion (clockwise, counter-clockwise), elongation, and shortening. More than 16,500 arm deformations were observed in 120 min of video. Results showed that all eight arms were capable of all four types of deformation along their lengths and in all directions. Arms function primarily to bring the sucker-lined oral surface in contact with target surfaces. Bending was the most common deformation observed, although the proximal third of the arms performed relatively less bending and more shortening and elongation as compared with other arm regions. These findings demonstrate the exceptional flexibility of the octopus arm and provide a basis for investigating motor control of the entire arm, which may aid the future development of soft robotics.We gratefully acknowledge funding from Grant N00014-19-1-2445 from the Office of Naval Research, Tom McKenna and Marc Steinberg, Program Managers. We also thank the staff of the Marine Resources Center at MBL for assistance with water quality measurements, seawater system maintenance, and collection of food items for octopuses

Storing Drinking-water in Copper pots Kills Contaminating Diarrhoeagenic Bacteria

Microbially-unsafe water is still a major concern in most developing countries. Although many water-purification methods exist, these are expensive and beyond the reach of many people, especially in rural areas. Ayurveda recommends the use of copper for storing drinking-water. Therefore, the objective of this study was to evaluate the effect of copper pot on microbially-contaminated drinking-water. The antibacterial effect of copper pot against important diarrhoeagenic bacteria, including Vibrio cholerae O1, Shigella flexneri 2a, enterotoxigenic Escherichia coli, enteropathogenic E. coli, Salmonella enterica Typhi, and Salmonella Paratyphi is reported. When drinking-water (pH 7.83±0.4; source: ground) was contaminated with 500 CFU/mL of the above bacteria and stored in copper pots for 16 hours at room temperature, no bacteria could be recovered on the culture medium. Recovery failed even after resuscitation in enrichment broth, followed by plating on selective media, indicating loss of culturability. This is the first report on the effect of copper on S. flexneri 2a, enteropathogenic E. coli, and Salmonella Paratyphi. After 16 hours, there was a slight increase in the pH of water from 7.83 to 7.93 in the copper pots while the other physicochemical parameters remained unchanged. Copper content (177±16 ppb) in water stored in copper pots was well within the permissible limits of the World Health Organization. Copper holds promise as a point-of-use solution for microbial purification of drinking-water, especially in developing countries

Early Detection of Potato Leaf Diseases using Convolutional Neural Network

Potato is the most important tuber crop in the world, with over 125 countries farming it. Potato, after rice and wheat, is the crop consumed by a billion people worldwide virtually every day. However, due to different fungal and bacterial illnesses, the quality and quantity of the potato crop is deteriorating. Early disease detection is difficult due to differences in environmental conditions, plant type, and plant disease symptoms. Several machine learning algorithms have been developed in recent study to recognize potato leaf diseases. In this work, a multi-layer deep learning model for detecting potato leaf disease is constructed. The features of the potato leaves are recovered from the image of the potato plant in the first layer using the image segmentation approach. A new deep learning technique based on a convolutional neural network [CNN] was created at the second level to detect fungal and bacterial infections in potatoes. The dataset for leaf disease contains 12000 photos gathered in real time and from the database. The proposed deep learning approaches identified potato diseases with 99.76% accurac