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Image J Analysis of Six Different Annealed Temperatures of 0.17% C of HSLA Steels

World Journal of Engineering and Technology 2020年第4期8卷 617-629页

作者： ngozi grace emordi Iweriolor Sunday Onyekpe Basil Obimma Department of Metallurgical Engineering Delta State Polytechnic Ogwashi Uku Nigeria Department of Mechanical Engineering Delta State Polytechnic Ogwashi Uku Nigeria Department of Mechanical Engineering University of Benin Benin Nigeria

Annealing is a heat treatment procedure in which the mechanical properties of a material are being altered, and such alterations cause changes in its properties such as strength and hardness. It is usually carried out to improve ductility and toughness, to reduce hardness and to remove carbides. This study deals with the use of image analysis processing method for the measurement of structure of six annealed samples of 0.17% High Strength Low Alloy (HSLA) Steels (840°C - 990°C) with 30°C interval and 30 minutes soaking time. From the optical microscope images using Image J program, some parameters like calculation of area, pixel value statistics, distances and angles measurements, edge detection, such as the circularity, ferret angle, solidity and perimeter, average area and the percentage area were examined. The annealed sample of 960°C gave the highest grain count of 543 with a perimeter of 41.518;standard deviation 7.057 and a mean of 28.722 which shows that annealing greatly improved the fatigue life of the steel. From the mechanical analysis result, the annealed sample at 840°C has a highest hardness value of 129.4 BHN and gave the lowest impact value of 58.75 J. This study shows a significant decrease in the hardness value as the annealing temperature increased which signifies that annealing temperature enhanced the fatigue property and tensile strength (wear strength) of the steel in study.

关键词： High Strength Low Alloy Steel Microstructure Image J

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Maximum Interval of Stability and Convergence of Solution of a Forced Mathieu’s Equation

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World Journal of Mechanics 2020年第11期10卷 210-219页

作者： Everestus Obinwanne Eze Uchenna Emmanuel Obasi Rosary ngozi Ujumadu grace Ihuoma Kalu Department of Mathematics Michael Okpara University of Agriculture Umuahia Nigeria Department of Mathematics Chukwuemeka Odimegwu Ojukwu University Uli Nigeria

This paper investigates the maximum interval of stability and convergence of solution of a forced Mathieu’s equation, using a combination of Frobenius method and Eigenvalue approach. The results indicated that the equilibrium point was found to be unstable and maximum bounds were found on the derivative of the restoring force showing sharp condition for the existence of periodic solution. Furthermore, the solution to Mathieu’s equation converges which extends and improves some results in literature.

关键词： Frobenius Method Eigenvalue Approach Stability Mathieu’s Equation

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Socio-Demographic Determinant of Yellow Fever Patient: A Retrospective Study (2020), Federal Medical Center, Asaba

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Journal of Biosciences and Medicines 2022年第12期10卷 225-238页

作者： ngozi Esther Ezunu Joy Ifeyinwa Egeonu Ajiri Henry Osihro Uyi-Oghosa Onyemushani Said Abdulkareem Omole Clementina Oyakhire Onyema Edith Wayemeru Chidera Olivia Okey-Ezufo Chikadibia Eze-Otulaka Faith Inegbejie Clever Ajiri Oghale Diana Chinenye Ofomata grace Nnenna Onubogu Orhomuromo Paul Okpomo Eguolo Unique Okorhi Onobhase Theresa Agbele Anastacia Okwudili Ojimba Adesuwa Queen Aigbokhaode Francis Chinedu Ugoeze Victor Azubike Osiatuma Emmanuel Okechukwu Ezunu Obianuju Nkemjika Jisieike Erhinyaye Omoyibo Efe Department of Nursing Federal Medical Centre Asaba Nigeria CCDRC Federal Medical Centre Asaba Nigeria Department of Internal Medicine Federal Medical Centre Asaba Nigeria Department of Radiology Federal Medical Centre Asaba Nigeria Department of Health Information Management Federal Medical Centre Asaba Nigeria Department of Pediatrics Federal Medical Centre Asaba Nigeria

Background: Yellow fever is transmitted primarily to humans and non-human primates through the bite of an infected female mosquito Aedes Spp. It is prevented mainly by vaccination. Method: This retrospective observational study at the Center for Communicable Disease Control and Research (CCDCR) Federal Medical Center Asaba (F.M.C) was conducted on all patients diagnosed and managed with yellow fever in the year 2020. We studied a total number of 57 patients’ case files seen within the period. A chi-square test was done to test the null and alternative hypotheses. Result: About 48 (84.2%) males and female 9 (15.8%) females were mostly affected and gender was significant with a chi-squared value of 26.6 and p-value of 0.00. Conclusion: To eradicate this virus, vaccination and health promotions should be encouraged by the health care workers supported by the government. This is to ensure that a greater proportion of the affected community can be immunized.

关键词： Yellow Fever Socio-Demograpic Determinants Asaba

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