Single-Phase Step-Up Switched-Capacitor-Based Multilevel Inverter Topology with SHEPWM

Multilevel inverter (MLI) topologies play a crucial role in the dc-ac power conversion due to their high-quality performance and efficiency. This article aims to propose a new switched-capacitor-based boost multilevel inverter topology (SCMLI). The proposed topology consists of nine power semiconductor switches with one dc voltage source and two capacitors, capable of generating a nine-level output voltage waveform with twice voltage gain. With the addition of two switches, the proposed topology can be used for higher voltage-gain applications. Other features of the proposed topology include the self-voltage balancing of the capacitors, parallel operation of the capacitors, lower voltage stress across the switches, along with the inherent polarity changing capability. To obtain the high-quality output waveform, a selective harmonic elimination pulsewidth modulation technique is applied. In this technique, the detrimental low-order harmonics can easily be regulated and eliminated from the output voltage of MLI. The proposed topology is compared with the recently introduced SCMLI topologies considering various parameters to set the benchmark of the proposed topology. The performance of the proposed MLI is investigated through various experimental results using a laboratory prototype setup.Manuscript received February 14, 2020; revised May 17, 2020 and June 6, 2020; accepted June 6, 2020. Date of publication June 12, 2020; date of current version May 19, 2021. Paper 2020-MCRE-0323.R2, approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Multilevel Converter applications in the area of Renewable Energy, More Electric Propulsion, Electric Vehicles and Power Grid Integration of the IEEE Industry Applications Society. This work was supported in part by the University of Malaya, Malaysia, under Impact Oriented Interdisciplinary Research Grant (IIRG): IIRG011A-2019 and in part by the Ministry of Higher Education, Malaysia, under Large Research Grant Scheme (LRGS): LR008-2019. (Corresponding author: Saad Mekhilef.) Marif Daula Siddique is with the Department of Electrical Engineering, Qatar University, Doha 177601, Qatar (e-mail: [email protected]).Scopu

The Frequency of Low Serum Cortisol Level in Acute Traumatic Brain Injury

Objective:  The study focused on evaluating the frequency of low serum cortisol levels in acute traumatic brain injury. Material and Methods:  Patients with Acute Traumatic Brain Injury of both genders between the ages of 2 and 70 years old with a GCS of 12 or below were included. Information including name, age, gender, pregnancy, GCS, serum cortisol level, history of steroid use, and hypothalamic-pituitary dysfunction were all recorded on a predesigned proforma. The results were stratified among age, sex, and GCS concerning outcome variables. Results:  The majority of patients (42%) ranged in age from 26 to 50. Male patients outnumbered female patients (77%). The GCS ranged between 9 and 12 in 63% of cases. Furthermore, 88 percent of patients had cortisol levels greater than 300nm/L. Hypocortisolemia was found in 13 people aged 26 to 50, 12 between the ages of 2 and 25, and only 7 between the ages of 51 and 70. There were 25 males and 7 women in the group. In 86 instances, GCS ranged from 9 to 12, while in 12 individuals, it varied from 3 to 8. Conclusion:  Although the majority of patients recovered, early hypopituitarism was common in severe TBI. It is required to identify concealed pituitary dysfunction in the course of the rehabilitation process of TBI patients. Keywords:  Cortisol, Traumatic Brain Injury, Hypocortisolemi

Three siblings with familial non-medullary thyroid carcinoma: a case series

Abstract BACKGROUND: In 2015, thyroid carcinoma affected approximately 63,000 people in the USA, yet it remains one of the most treatable cancers. It is mainly classified into medullary and non-medullary types. Conventionally, medullary carcinoma was associated with heritability but increasing reports have now begun to associate non-medullary thyroid carcinoma with a genetic predisposition as well. It is important to identify a possible familial association in patients diagnosed with non-medullary thyroid carcinoma because these cancers behave more destructively than would otherwise be expected. Therefore, it is important to aggressively manage such patients and screening of close relatives might be justified. Our case series presents a diagnosis of familial, non-syndromic, non-medullarycarcinoma of the thyroid gland in three brothers diagnosed over a span of 6 years. CASE PRESENTATIONS: We report the history, signs and symptoms, laboratory results, imaging, and histopathology of the thyroid gland of three Pakistani brothers of 58 years, 55 years, and 52 years from Sindh with non-medullary thyroid carcinoma. Only Patients 1 and 3 had active complaints of swelling and pruritus, respectively, whereas Patient 2 was asymptomatic. Patients 2 and 3 had advanced disease at presentation with lymph node metastasis. All patients underwent a total thyroidectomy with Patients 2 and 3 requiring a neck dissection as well. No previous exposure to radiation was present in any of the patients. Their mother had died from adrenal carcinoma but also had a swelling in the front of her neck which was never investigated. All patients remained stable at follow-up. CONCLUSIONS: Non-medullary thyroid carcinoma is classically considered a sporadic condition. Our case report emphasizes a high index of suspicion, a detailed family history, and screening of first degree relatives when evaluating patients with non-medullarythyroid carcinoma to rule out familial cases which might behave more aggressively

Scientific papers citation analysis using textual features and SMOTE resampling techniques

Abstract Ascertaining the impact of research is significant for the research community and academia of all disciplines. The only prevalent measure associated with the quantification of research quality is the citation-count. Although a number of citations play a significant role in academic research, sometimes citations can be biased or made to discuss only the weaknesses and shortcomings of the research. By considering the sentiment of citations and recognizing patterns in text can aid in understanding the opinion of the peer research community and will also help in quantifying the quality of research articles. Efficient feature representation combined with machine learning classifiers has yielded significant improvement in text classification. However, the effectiveness of such combinations has not been analyzed for citation sentiment analysis. This study aims to investigate pattern recognition using machine learning models in combination with frequency-based and prediction-based feature representation techniques with and without using Synthetic Minority Oversampling Technique (SMOTE) on publicly available citation sentiment dataset. Sentiment of citation instances are classified into positive, negative or neutral. Results indicate that the Extra tree classifier in combination with Term Frequency-Inverse Document Frequency achieved 98.26% accuracy on the SMOTE-balanced dataset

A new eight switch seven level boost active neutral point clamped (8S-7L-BaNPC) inverter

A new boost Active-Neutral-Clamped (ANPC) voltage boosting inverters are appealing for low dc-link voltage demand. Recent boost ANPC topology has demonstrated a 1.5 times voltage gain, but the number of switches has a higher number. This paper proposed an improved boost ANPC topology with 1.5 voltage gain using the least number of switches. Further, the number of conducting switches has been reduced remarkably which enhances the system efficiency. The seven-level (7L) output voltage levels are achieved using a floating capacitor with self-voltage balancing capability. The proposed topology has been analyzed and compared to the ANPC topologies proposed in recent years. For the validation of the theoretical aspect of the proposed topology, the experimental findings have been compiled in the paper.This work was supported by the Qatar University-Marubeni Concept to Prototype Development Research grant # [MCTP-CENG-2020-2] from the Qatar University and the publication charges is paid by the Qatar National Library, Doha, Qatar.Scopu

11 Level boost inverter topology with dual-source configuration

With the advancement of the application of power converters in the power industry, the research towards the prominent power converter namely multilevel inverter has gained a lot of attraction. Here, a dual-source configured 11 level inverter topology is being discussed, which uses nine power semiconductor devices and one capacitor. The proposed topology is able to charge the capacitor up to 2Vdc which provides the boosting feature with the voltage gain of 1.67. An extended comparison with several other topologies has been provided which highlights the major contribution of the work. A low-power laboratory prototype has been used for the validation of the proposed 11 level topology. Further, a thorough assessment of comparable topologies has been conferred in detail. 2022 The Authors. IET Power Electronics published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.The authors acknowledge the support provided by King Abdullah City for Atomic and Renewable Energy (K.A.CARE) under K.A.CARE-King Abdulaziz University Collaboration Program. The Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia has funded this project, under grant no. (FP-108-43) and also the United Arab Emirates University (UAE-U) for supporting this research work through the AUA grants #12R022 and #31R280.Scopu

7L-SCBI topology with minimal semiconductor device count

In this work, a seven-level switched capacitor boost inverter (7L-SCBI) is proposed with minimal resource count. The proposed inverter requires only eight switches and two capacitors to generate a seven-level voltage. The proposed 7L-SCBI is capable of generating a multilevel voltage as well as boost the input DC-link voltage up to 1.5 times with a reduced blocking voltage of switches and capacitors. The comparison in terms of efficiency and device count with other switched capacitor topologies is presented in detail. The performance validation of the proposed 7L-SCBI is done with the help of a laboratory prototype. reserved.This publication was made possible by Qatar University-Marubeni Concept to Prototype Development Research grant # [M-CTP-CENG-2020-2] from the Qatar University. The statements made herein are solely the responsibility of the authors.Scopu

A New Multilevel Inverter Topology with Reduce Switch Count

Multilevel inverters are a new family of converters for dc-ac conversion for the medium and high voltage and power applications. In this paper, two new topologies for the staircase output voltage generations have been proposed with a lesser number of switch requirement. The first topology requires three dc voltage sources and ten switches to synthesize 15 levels across the load. The extension of the first topology has been proposed as the second topology, which consists of four dc voltage sources and 12 switches to achieve 25 levels at the output. Both topologies, apart from having lesser switch count, exhibit the merits in terms of reduced voltage stresses across the switches. In addition, a detailed comparative study of both topologies has been presented in this paper to demonstrate the features of the proposed topologies. Several experimental results have been included in this paper to validate the performances of the proposed topologies with different loading condition and dynamic changes in load and modulation indexes.This work was supported by the Qatar University through the QU High Impact Grant QUHI-CENG-19/20-2. The statements made herein are solely the responsibility of the authors. The publication charges are funded by the Qatar National Library, Doha, Qatar.Scopu

Bioprospecting desert plant Bacillus endophytic strains for their potential to enhance plant stress tolerance

© 2019, The Author(s). Plant growth-promoting bacteria (PGPB) are known to increase plant tolerance to several abiotic stresses, specifically those from dry and salty environments. In this study, we examined the endophyte bacterial community of five plant species growing in the Thar desert of Pakistan. Among a total of 368 culturable isolates, 58 Bacillus strains were identified from which the 16 most divergent strains were characterized for salt and heat stress resilience as well as antimicrobial and plant growth-promoting (PGP) activities. When the 16 Bacillus strains were tested on the non-host plant Arabidopsis thaliana, B. cereus PK6-15, B. subtilis PK5-26 and B. circulans PK3-109 significantly enhanced plant growth under salt stress conditions, doubling fresh weight levels when compared to uninoculated plants. B. circulans PK3-15 and PK3-109 did not promote plant growth under normal conditions, but increased plant fresh weight by more than 50% when compared to uninoculated plants under salt stress conditions, suggesting that these salt tolerant Bacillus strains exhibit PGP traits only in the presence of salt. Our data indicate that the collection of 58 plant endophytic Bacillus strains represents an important genomic resource to decipher plant growth promotion at the molecular level

General practitioner\u27s knowledge regarding the diagnosis and drug therapy for acute myocardial infarction

OBJECTIVE: To assess the general practitioners (GP) knowledge regarding the diagnosis and initial drug therapy for acute myocardial infarction (AMI). METHODS: A questionnaire-based survey was conducted in randomly selected GPs of Karachi. Doctors working in community as GPs who were registered medical practitioners having a Bachelor of Medicine & Bachelor of Surgery degree were included in the study. Doctors working at tertiary care facilities or having a post graduate degree or post graduate training in a specialty other than family medicine were excluded from the study. RESULTS: A total of 186 GPs participated in our study. GPs who studied research journals were 2.33 times more likely to investigate serum cardiac troponins levels for the diagnosis of AMI compared to those who did not study research journals (P = 0.02). Twenty six percent of the GPs said that they would refer a patient with suspected AMI without treatment, while 76% said that they would consider some treatment prior to referral. Fifty eight percent of the GPs identified ST segment elevation myocardial infarction (STEMI) of \u3c 12 hours duration as an indication of thrombolysis while 28% identified posterior wall AMI as a thrombolytic indication. CONCLUSION: GPs, although adequately aware of the presenting features of AMI, were lacking in knowledge regarding the means for confirmation of diagnosis, initial drug therapy and were less likely to carry management steps in their practice