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Comparative Study of E-Learning Experiences: A Case Study of Nigeria, South Africa and United States
Moses Timothy,Oladunjoye John A,Agu Edward O 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.10
We are in a society where availability of open courseware and countless internet-based online programmes are run by universities across the globe. The world is moving from the traditional face-to-face classroom teaching to a virtual classroom. There are concerns however; that this paradigm shift is limited by the understanding on what quality/standard is needed for a good e-learning resource. This concern has prompted the need to compare e-learning experiences in United States, South Africa and Nigeria so as to encourage developing countries to improve on this innovative approach to learning.
Analysis of multi leaf spring based on contact mechanics - a novel approach
Kumaravelan, R.,Ramesh, S.,Gandhi, V.C. Sathish,Agu, M. Joemax,Thanmanaselvi, M. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.3
A leaf spring, especially the longitudinal type is liable and persistent element in automotive suspension system. In the present scenario the composite materials are widely used in the automobile industries has shown a great interest in the replacement of steel spring due to high strength by weight ratio. Previous investigations focused on stresses and displacement analysis of single leaf spring for different materials. The present work aims to design and analysis of leaf spring for two different cases by considering the Young's modulus to yield strength ratio. In the first case the analysis deals with the design and analysis of a single cantilever solid triangle beam which is an equivalent beam of a spring with three leaves having uniform strength. In the second case a 3-beams of rectangular cross section has been considered which is equivalent to a spring with three leaves. The analysis was carried out based on contact mechanics approach. The results were compared, that the fiberglass composite leaf spring is suitable for high loading capacity, reliability and efficiency.
Analysis of multi leaf spring based on contact mechanics – a novel approach
R. Kumaravelan,S. Ramesh,V.C. Sathish Gandhi,M. Joemax Agu,M. Thanmanaselvi 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.3
A leaf spring, especially the longitudinal type is liable and persistent element in automotive suspension system. In the present scenario the composite materials are widely used in the automobile industries has shown a great interest in the replacement of steel spring due to high strength by weight ratio. Previous investigations focused on stresses and displacement analysis of single leaf spring for different materials. The present work aims to design and analysis of leaf spring for two different cases by considering the Young's modulus to yield strength ratio. In the first case the analysis deals with the design and analysis of a single cantilever solid triangle beam which is an equivalent beam of a spring with three leaves having uniform strength. In the second case a 3- beams of rectangular cross section has been considered which is equivalent to a spring with three leaves. The analysis was carried out based on contact mechanics approach. The results were compared, that the fiberglass composite leaf spring is suitable for high loading capacity, reliability and efficiency.
Pro-fertility effects of hydroalcoholic extract of Psidium guajava leaves in female Wistar rats
Saleh Adamu Abwage,Saganuwan Alhaji Saganuwan,Solomon Tsekohol Agu,Hyacinth Adakole Abu 경희대학교 융합한의과학연구소 2023 Oriental Pharmacy and Experimental Medicine Vol.23 No.1
Psidium guajava is a renowned plant used by African traditional medical practitioners because of its numerous therapeutic benefits but little is known of its positive effects on female fertility. The Pro-fertility effects of hydroalcoholic extract of Psidium guajava leaves in female Wistar rats were investigated in the present study. Four (4) groups of five (5) rats each were used for the study. Group A is the control received” Tween 20®”. Groups B, C, and D rats received 100, 200 and 400 mg/kg body weight of the hydroalcoholic extract of P. guajava (HEPG) leaves respectively for 19 days. The rats were laparatomised on day 20 and the number of corpora lutea of pregnancy, number of live fetuses, the weight of the fetuses and placentae as well as the postcoital fertility index were recorded. Oral administration of HEPG leaves from day 1–19 significantly (P < 0.05) caused an increase in maternal body weights, average weight of the placenta, ovary, and foetus in a dose-dependent-manner in the treated groups as compared with the control group. Progressive increase in the number of pregnant rats, number of rats showing implantation, number of the live foetus and mean corpus luteum number (CLN) per female, foetal crown-rump length (FCRL), percentage of a pregnant female in each group (PPF), and fertility index (FI) in a dose-dependent-manner, when the test groups are compared to control group. The results suggest that HEPG leaves could induce positive effects on the reproductive system in female albino rats.
Stanley Anyanwu,Imeobong J. Inyang,Enosakhare A. Asemota,Okechi O. Obioma,Dorathy C. Okpokam,Victoria O. Agu 한국한의학연구원 2017 Integrative Medicine Research Vol.6 No.3
Background: The use of plants and plant products for medicinal purposes is an age-long practice in traditional communities and is becoming prominent globally. This study was performed to evaluate the effect of ethanolic extract of Chromolaena odorata on the kidney and intestine of albino rats. Methods: Twenty growing albino rats with an average weight of 54 g were used in this study. They were grouped into four groups. Groups 1, 2, and 3, known as the test groups, were given 50 mg/kg, 100 mg/kg, and 250 mg/kg ethanolic extract of C. odorata, respectively, while the control group was given distilled water orally. The experiment was performed for 6 weeks. The animals were killed using chloroform suffocation. The kidneys and the intestine were harvested and fixed in 10% neutral buffered formalin for histological analysis. Blood samples were collected from the animals by heart puncture for estimation of creatinine and urea levels. Results: The creatinine, urea, aspartate aminotransferase, alanine transaminase, and alkaline phosphatase levels of blood sample from the test group were significantly different when compared with the control (p < 0.05). The histological sections of the kidneys in this study showed no signs of degeneration. Infiltration of inflammatory cells and epithelial erosion were observed in the histology sections of the intestine of all the test groups. Conclusion: The results from this study revealed that uncontrolled use of this plant extract has an adverse effect on the kidney function and on the histology of the intestine of the rats used in this study.
Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
Abbott, B. P.,Abbott, R.,Abbott, T. D.,Acernese, F.,Ackley, K.,Adams, C.,Adams, T.,Addesso, P.,Adhikari, R. X.,Adya, V. B.,Affeldt, C.,Afrough, M.,Agarwal, B.,Agathos, M.,Agatsuma, K.,Aggarwal, N.,Agu American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.848 No.2
<P>On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB. 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB. 170817A and GW170817 occurring by chance is 5.0 x 10(-8). We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB. 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of (+ 1.74 +/- 0.05) s between GRB. 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between -3 x 10(-15) and + 7 x 10(-16) times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB. 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity.</P>
Full band all-sky search for periodic gravitational waves in the O1 LIGO data
Abbott, B. P.,Abbott, R.,Abbott, T. D.,Acernese, F.,Ackley, K.,Adams, C.,Adams, T.,Addesso, P.,Adhikari, R. X.,Adya, V. B.,Affeldt, C.,Afrough, M.,Agarwal, B.,Agathos, M.,Agatsuma, K.,Aggarwal, N.,Agu American Physical Society 2018 Physical Review D Vol.97 No.10
<P>We report on a new all-sky search for periodic gravitational waves in the frequency band 475-2000 Hz and with a frequency time derivative in the range of [-1.0, +0.1] x 10(-8) Hz/s. Potential signals could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the data from Advanced LIGO's first observational run 01. No gravitational-wave signals were observed, and upper limits were placed on their strengths. For completeness, results from the separately published low-frequency search 20-475 Hz are included as well. Our lowest upper limit on worst-case (linearly polarized) strain amplitude h 0 is similar to 4 x 10(-25) near 170 Hz, while at the high end of our frequency range, we achieve a worst-case upper limit of 1.3 x 10(-24) . For a circularly polarized source (most favorable orientation), the smallest upper limit obtained is similar to 1.5 x 10(-25)</P>
On the Progenitor of Binary Neutron Star Merger GW170817
Abbott, B. P.,Abbott, R.,Abbott, T. D.,Acernese, F.,Ackley, K.,Adams, C.,Adams, T.,Addesso, P.,Adhikari, R. X.,Adya, V. B.,Affeldt, C.,Afrough, M.,Agarwal, B.,Agathos, M.,Agatsuma, K.,Aggarwal, N.,Agu American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.850 No.2
<P>On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB. 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just similar to 40Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of similar to 2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr.</P>