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Inter-cluster voltage balancing control of a delta connected modular multilevel cascaded converter under unbalanced grid voltage

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Protection and Control of Modern Power Systems 2021年第1期6卷 289-299页

作者： Oghenewvogaga J.K.Oghorada Li Zhang Huang Han ayodele B.esan Mingxuan Mao SDG-7 Affordable and Clean Energy Research GroupLandmark UniversityOmu-AranNigeria Department of Electrical and Information Engineering Landmark UniversityOmu-AranNigeria School of Electronic and Electrical Engineering University of LeedsLeedsUK College of Engineering Swansea UniversitySwanseaUK School of Electrical Engineering Chongqing UniversityChongqingChina

A new inter-cluster DC capacitor voltage balancing scheme for a delta connected modular multilevel cascaded converter (MMCC)-based static synchronous compensator (STATCOM) is presented. A detailed power flow analysis of applying negative sequence current (NSC) and zero-sequence current (ZSC) injection methods in addressing the issue of inter-cluster DC voltage imbalance under unbalance grid voltage is carried out. A control scheme is proposed which integrates both inter-cluster methods using a quantification factor QF. This is used to achieve the sharing of the inter-cluster active power between the NSC and ZSC injection methods. An accurate method of determining the quantification factor is also presented. The proposed method offers better sub-module DC capacitor voltage balancing and prevents converter overcurrent. The influence of unbalanced grid voltage on the delta connected MMCC-based STATCOM rating using this integrated cluster balancing technique is investigated. The control scheme is verified with a 5 kV 1.2MVA MMCC-STATCOM using 3-level bridge sub-modules, and the results show the advantages of the proposed method over other inter-cluster methods.

关键词： Low voltage ride through(LVRT) Single delta bridge converter(SDBC) Static synchronous compensator(STATCOM) Quantification factor

Classification, Tectonic Setting, and Mineralization Potential of Ayetoro and Sasaro Syenitic Plutons in Igarra Schist Belt, Southwestern Nigeria

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International Journal of Geosciences 2024年第6期15卷 493-510页

作者： Mohammed Olatoye Adepoju Yinusa ayodele Asiwaju-Bello Department of Applied Geology Federal University of Technology Akure Nigeria

Petrographic and geochemical studies of syenite-looking Ayetoro and Sasaro plutons within Igarra Schist Belt were carried out in order to classify them and determine their tectonic setting and mineralization potential. Petrographic study and geochemical classification revealed that while Ayetoro boss is microgranite constituting an aggregate of medium grained muscovite, quartz and biotite minerals, Sasaro stock is micromonzonite made up of medium grained albite, orthoclase, biotite, hornblende and pyroxene. Geotectonic setting showed the boss and stock are orogenic, probably derived from the same upper mantle magma as Igarra batholith that got contaminated by crustal materials responsible for their difference in lithology. Their mineralization potential showed that the massive Ayetoro microgranite with no appreciable trace-element contents cannot serve as host of any metallic deposit, and should be suitable for industrial applications. Whereas, the silicified, highly sheared Sasaro monzonite, with elevated level of some trace elements contents as Ag, Au and Cu, could harbor Ag-Au-Cu deposit.

关键词： ICP-MS Microgranite Micromonzonite Orogenic Ag-Au-Cu Deposit Igarra Schist Belt

A Novel Insertion Solution for the Travelling Salesman Problem

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Computers, Materials & Continua 2024年第4期79卷 1581-1597页

作者： Emmanuel Oluwatobi Asani Aderemi Elisha Okeyinka Sunday Adeola Ajagbe ayodele Ariyo Adebiyi Roseline Oluwaseun Ogundokun Temitope Samson Adekunle Pragasen Mudali Matthew Olusegun Adigun Department of Computer Science Landmark UniversityOmu Aran251103Nigeria SDG 11 Group Landmark UniversityOmu Aran251103Nigeria Department of Computing MiVA UniversityAbuja900211Nigeria Department of Computer Science Ibrahim Badamasi Babangida UniversityLapai911101Nigeria Department of Computer Science University of ZululandKwadlangezwa3886South Africa Department of Computer&Industrial Production Engineering First Technical UniversityIbadan200243Nigeria Department of Multimedia Engineering Kaunas University of TechnologyKaunasLT-44249Lithuania Department of Computer Science Colorado State UniversityFort Collins80523USA

The studypresents theHalfMax InsertionHeuristic (HMIH) as a novel approach to solving theTravelling SalesmanProblem (TSP). The goal is to outperform existing techniques such as the Farthest Insertion Heuristic (FIH) andNearest Neighbour Heuristic (NNH). The paper discusses the limitations of current construction tour heuristics,focusing particularly on the significant margin of error in FIH. It then proposes HMIH as an alternative thatminimizes the increase in tour distance and includes more nodes. HMIH improves tour quality by starting withan initial tour consisting of a ‘minimum’ polygon and iteratively adding nodes using our novel Half Max *** paper thoroughly examines and compares HMIH with FIH and NNH via rigorous testing on standard TSPbenchmarks. The results indicate that HMIH consistently delivers superior performance, particularly with respectto tour cost and computational efficiency. HMIH’s tours were sometimes 16% shorter than those generated by FIHand NNH, showcasing its potential and value as a novel benchmark for TSP solutions. The study used statisticalmethods, including Friedman’s Non-parametric Test, to validate the performance of HMIH over FIH and *** guarantees that the identified advantages are statistically significant and consistent in various situations. Thiscomprehensive analysis emphasizes the reliability and efficiency of the heuristic, making a compelling case for itsuse in solving TSP issues. The research shows that, in general, HMIH fared better than FIH in all cases studied,except for a few instances (pr439, eil51, and eil101) where FIH either performed equally or slightly better thanHMIH. HMIH’s efficiency is shown by its improvements in error percentage (δ) and goodness values (g) comparedto FIH and NNH. In the att48 instance, HMIH had an error rate of 6.3%, whereas FIH had 14.6% and NNH had20.9%, indicating that HMIH was closer to the optimal solution. HMIH consistently showed superior performanceacross many benchmarks,

关键词： Nearest neighbour heuristic farthest insertion heuristic half max insertion heuristic tour construction travelling salesman problem

The significance of metabolic fingerprinting in carcinogenesis

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Cancer Advances 2024年第1期7卷 1-6页

作者： ayodele Ademola Adelakun Princess Adekunbi Owokalade Department of Medical Laboratory Science Ladoke Akintola University of TechnologyOgbomoso 210001Nigeria Department of Medical Laboratory Science Babcock UniversityIlishan-Remo 121103Nigeria

Carcinogenesis describes the process through which normal cells transform into malignant cells(cancer).There were an estimated 18.1 million new cases of cancer(all cancers combined excluding non-melanoma skin cancer)worldwide in 2020:8.8 million(48%)in females and 9.3 million(52%)in males,giving a male:female ratio of 10:*** may be initiated by the action of biological,physical,or chemical agents that cause a non-lethal,permanent,DNA error on the cell with a consequence of altered cell *** altered cell metabolism include the Warburg effect,altered lipid and amino acid metabolism and production of various *** also results in unique metabolic dependencies that,in some cases,can be targeted with precision medicine and nutrition,including drugs that selectively target metabolic *** fingerprinting has been applied to the study of carcinogenesis and is particularly helpful in early diagnosis,staging and choice of treatment,thus improving health *** technology could therefore be harnessed effectively while combining with other omics technologies.

关键词： cancer metabolomics prognosis diagnosis fingerprint

Influence of Non-Natural Ageing Temperature on the Microstructural Characteristics and Mechanical Properties of Cast Aluminum 6063 Alloy

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 91-99页

作者： Oluwole Oladele ayodele Adedeke Olajesu Olanrewaju Samuel Olusunle Department of Metallurgical and Materials Engineering Federal University of Technology Akure Ondo State Nigeria Engineering Materials Development Institute NASENI Akure Ondo State Nigeria Department of Materials Science and Engineering Iowa State University Ames IA USA NASENI Abuja Nigeria

This research considered the effect of non-natural aging on the microstructural characteristics and mechanical properties of as-cast aluminum 6063 alloys. The samples were developed through a sand casting process and machined into tensile and impact test samples before carrying out solution heat treatment at 550?C (0.83 Tm) on two parts of the samples while retaining one part as the control. The two parts were further divided into sets denoted A and B and were aged at 180?C (0.27 Tm) and 160?C (0.24 Tm), respectively, for 12 hours. The results showed that sample A has the optimal yield strength and ultimate tensile strength of 192 and 206 MPa, respectively. Likewise, the sample gave the highest impact strength value of about 9.63 J/mm2. The observed results were supported by the optical micrograph, which revealed that the sample has evenly dispersed precipitates in its microstructure. This is deemed responsible for the observed increase in strength of the sample.

关键词： Aluminum Alloy Non-Natural Ageing Mechanical Properties Microstructural Features

Detection of Partial and Extended Blockages: A Case Study of Edible Oil Pipeline System

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Journal of Minerals and Materials Characterization and Engineering 2024年第3期12卷 204-223页

作者： Babatunde Victor Omidiji ayodele Abeeb Daniyan Adeniyi Taiwo Kunle Michael Oluwasegun Department of Mechanical Engineering Obafemi Awolowo University Ile-Ife Nigeria Department of Materials Science and Engineering Obafemi Awolowo University Ile-Ife Nigeria Department of Mechanical Engineering First Technical University Ibadan Nigeria Department of Mechanical Engineering University of Manitoba Manitoba Canada

This work focuses on the development and implementation of a simulation-based approach for the detection of partial and extended blockages within an edible oil pipeline system. Blockages, whether partial or extended, pose a significant operational and safety risks. This study employs computational fluid dynamics (CFD) simulations to model the flow behaviour of edible oil through pipeline under varying conditions. It leverages advanced computational fluid dynamics (CFD) simulations to analyze pressure, velocity, and temperature variations along the pipeline. By simulating scenarios with different blockage characteristics, there is establishment of distinctive patterns indicative of partial and extended obstructions. Through extensive analysis of simulation data, sensing element, and monitoring system, processing signal input and response output, the system can accurately pinpoint the location and severity of blockages, providing crucial insights for timely intervention. The detection system represents a significant advancement in pipeline monitoring technology, offering a proactive and accurate approach to identify blockages and mitigate potential risks and ensure the uninterrupted flow of edible oil, thereby enabling timely intervention and maintenance.

关键词： Computational Fluid Dynamics (CFD) Simulations Pipeline Blockages

Fournier’s Gangrene: 13-Year Experience in a Tertiary Center, North Eastern Nigeria

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Open Journal of Urology 2024年第7期14卷 407-414页

作者： Makama Baje Salihu Haruna Liman Stephen Yusuf Aminu Umar Oladimeji Abraham Tunde ayodele Olufikayo Oshagbemi Amur Ibrahim Urology Unit Department of Surgery Abubakar Tafawa Balewa University Teaching Hospital Bauchi Nigeria

Background: Fournier’s gangrene is a fulminant infection of the genitourinary tract characterized by progressive necrosis of the skin and subcutaneous tissue of the external genitalia. Initially mainly seen involving the scrotum of elderly men with different moods of occurrence each unpleasantly lethal. With varying types of presentation only one thing has remained constant;the poor prognosis of this condition. Purpose/Aim: Thus, it’s important to study the trends of the presentation of this condition laying emphasis on the challenges in the management of these patients;both the negative and positive prognostic factors. Materials and Methods: Urology ward record books, clinic record books and operating theater records were used to identify patients managed for Fournier gangrene in ATBUTH Bauchi. A retrospective study of the medical files of all the patients managed from January 2011 to January 2024 was done. Data was analyzed using SPSS version 29. Results: Data from 47 patients seen during the period of study were carefully collected and analyzed. The age range is 2 weeks to 97 years. There were two neonates, one at 2nd week of life and the other at 3rd week. Mortality rate is 36%. The average time duration before presentation for patients that died was two weeks, a minimum of 9 days prior to presentation and a maximum of 21 days, about 10 of which came in septic shock and the remaining presented with fever and very extensive necrotizing fasciitis of the perineum. All the patients that died had diabetes mellitus as a comorbidity except the neonate. All the patients that survived were much younger, all were below 60 years of age (2 weeks - 53 years). Conclusion: Here, we share our experience managing patients with Fournier’s gangrene in our facility in the past 13-year period from January 2011 to January 2024. .

关键词： Fournier’s Gangrene Prognosis Elderly Presentation Treatment

COVID-19 Vaccination Uptake and Associated Factors in Selected Communities in Two Southwestern States in Nigeria

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Advances in Infectious Diseases 2024年第1期14卷 260-278页

作者： Oluseye ayodele Ajayi Olabanjo Okunlola Ogunsola Ajibola Idowu Oluwaseun Kikelomo Ajayi Kucheli Wudiri Rita Asoka-Ikechukwu Prosper Okonkwo APIN Public Health Initiatives Abuja Nigeria Department of Community Medicine Bowen University Teaching Hospital Ogbomosho Nigeria Department of Community Medicine University College Hospital Ibadan Nigeria

Introduction: COVID-19 vaccine uptake and acceptance have been a major global concern due to the prevalent misinformation and disinformation that has characterized the vaccine rollout worldwide. This study aimed to assess COVID-19 vaccine uptake and acceptance, and associated factors among selected community members in two states in southwestern Nigeria. Method: We conducted a cross-sectional study using a multistage sampling technique. Fifty catchment settlements of 10 health facilities in each of Oyo and Ogun States targeted for a COVID-19 infection prevention and control intervention were randomly selected. Four households were targeted per settlement. All households that refused access were replaced, to ensure a minimum of four households randomly selected per settlement. The primary household decision-maker was interviewed in each household. Information elicited included respondents’ sociodemographic characteristics, health history, knowledge, risk and benefit perception about the COVID-19 vaccine, vaccine uptake, and willingness to be vaccinated. The study was conducted from July–August 2021. Data were analyzed using SPSS IBM version 23. Result: Four hundred household decision-makers were surveyed in Oyo and Ogun states, after replacement. The mean age of the respondents was 43.0 ± 11.0 years. The majority, 346 (86.5%) had heard about COVID-19 vaccination, but only 47 (13.6%) had received a COVID-19 vaccination. Of the 299 respondents who reported not receiving a COVID-19 vaccination, 166 (55.5%) were willing to be vaccinated. In univariate analysis, respondents who were female had tertiary education, perceived that COVID-19 vaccines are free and accessible, perceived that COVID-19 vaccines have minimal side effects, and perceived higher benefits of COVID-19 vaccination had higher odds of being vaccinated. In contrast, younger respondents, respondents with higher knowledge scores on COVID-19 preventive measures, and with chronic illness had lower likelihoods

关键词： COVID-19 Vaccination Vaccine Vaccine Uptake

Adjuvant Rectal Diclofenac for Post Operative Analgesia after Caesarean Section—A Randomized Controlled Study

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Open Journal of Obstetrics and Gynecology 2024年第4期14卷 591-609页

作者： Eziaha Eric S. Ede ayodele A. Olaleye John C. Irechukwu Uchenna Nelson Nwaedu Borniface N. Ejikeme Vincent Chidiebere Ali Bartholomew I. Olinya Department of Obstetrics and Gynaecology Alex Ekwueme Federal University Teaching Hospital Abakaliki Nigeria

BACKGROUND: Pain management following caesarean section still remains a challenge in our environment. Most potent analgesics are either not readily available or expensive. Diclofenac suppository is an NSAID that can be used for postoperative analgesia. It is available and affordable. OBJECTIVE: To compare the efficacy and safety of combined rectal diclofenac and intramuscular pentazocine with intramuscular pentazocine alone for post operative pain control following lower segment caesarean section. METHODOLOGY: A total of 120 women who met the selection criteria scheduled for caesarean section under spinal anaesthesia with bupivacaine were randomized into two equal groups to receive either 75 mg diclofenac suppository 12 hourly for 24 hours or one anusol suppository (the placebo) 12 hourly for 24 hours. Both groups received pentazocine as primary analgesia. RESULT: The primary outcome measure is the proportion of patients with severe pain at 24 hours using the visual analogue rating scale. Secondary outcome measures are the time from surgery to ambulation, Passage of flatus, maternal satisfaction and presence of complications. Statistical analysis was done using spss version 22 and graph pad statistical package. Student T-test was used for continuous variables whereas chi square was used for categorical variables P CONCLUSION: Adjuvant rectal diclofenac is superior to pentazocine alone in the management of pain after caesarean section. Less number of patients had moderate to severe pain at 24 hours post operation. Maternal satisfaction in relation to pain management is better with diclofenac suppository. The levels of complications were comparable in both groups.

关键词： Pain Caesarean Section Diclofenac Placebo Suppository