Limit load equations for partially restrained RC slabs

Olufemi, O.O.,Cheung, K.L.,Hossain, K.M.A. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.19 No.1

The expertise required in the judicious use of nonlinear finite element (FE) packages for design-assistance purposes is not widely available to the average engineer, whose sole aim may be to obtain an estimate for a single design parameter, such as the limit load capacity of a structure. Such a parameter may be required for the design of a proposed reinforced concrete (RC) floor slab or bridge deck with a given set of geometrical and material details. This paper outlines a procedure for developing design-assistance equations for carrying out such predictions for partially restrained RC slabs under uniformly distributed loading condition, based on a database of FE results previously generated from a large number of 'numerical model' slabs. The developed equations have been used for predicting the peak loads of a number of experimental RC slabs having varying degrees of edge restraints; with results showing a reasonable degree of accuracy and low level of scatter. The simplicity of the equations makes them attractive and their successful use in the field of application reported in this paper suggest that the outlined procedure may also be extended to other classes of concrete structures.

Limit load equations for partially restrained RC slabs

O. O. Olufemi,K. L. Cheung,K. M. A. Hossain 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.19 No.1

The expertise required in the judicious use of nonlinear finite element (FE) packages for design-assistance purposes is not widely available to the average engineer, whose sole aim may be to obtain an estimate for a single design parameter, such as the limit load capacity of a structure. Such a parameter may be required for the design of a proposed reinforced concrete (RC) floor slab or bridge deck with a given set of geometrical and material details. This paper outlines a procedure for developing design-assistance equations for carrying out such predictions for partially restrained RC slabs under uniformly distributed loading condition, based on a database of FE results previously generated from a large number of ‘numerical model’ slabs. The developed equations have been used for predicting the peak loads of a number of experimental RC slabs having varying degrees of edge restraints; with results showing a reasonable degree of accuracy and low level of scatter. The simplicity of the equations makes them attractive and their successful use in the field of application reported in this paper suggest that the outlined procedure may also be extended to other classes of concrete structures.

Giant Solitary Anterior Cervical Canal Neurofibroma: Case Report and Surgical Technique

Olufemi Emmanuel Idowu,Kazeem M. Atobatele,Sunday O. Soyemi 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.4

Giant solitary anterior cervical canal neurofibroma (GSACCN) is rarely reported in the literature. When the large lesion is ventrally located to the spinal cord, an anterolateral approach may not be ideal due to various technical challenges. In this report, we describe a case of intradural extramedullary GSACCN located at the cervical region extending from the axis to the sixth cervical vertebrae. Here we also describe a posterior technique successfully used to resect the tumour. Therefore, the posterior approach by en bloc decompressive laminectomy and laminoplasty might be used to adequately treat the lesion.

Assessment of soil contamination at the central sewage treatment plant, University of Nigeria, Nsukka

Solomon O. Onwuka,Mosto K. Onuoha,Olufemi V. Omonona 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.1

This paper integrated geophysical and geochemical methods to study the pollution of soil at the sewage plant at the University of Nigeria, Nsukka. The plant has two large stabilization ponds. Vertical electrical sounding (VES) was carried out to determine the depth of plume, and thus evaluate the safety of the underlying water table aquifer. Tracking of plume direction was by the application of horizontal profiling (HP) and induced polarization (IP). Geochemical analysis of 12 soil samples collected at 1 m and 5 m depths from 6 augured holes around the plant were carried out to evaluate the levels of concentration of the pollutants via their pollution indices (geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF), pollution load index (PLI)). Results of the 22 VES shots showed the depth of plume to be about 40 m. Together with VES and aquifer vulnerability mapping techniques a plume migration rate of 0.76 m/yr was evaluated and thus, it would take 144 years to reach the aquifer at average water table depth of 110 m. The HP and IP showed concentrations of plume face towards the northeast of the plant. The total dissolved solids (TDS) and pollution indices were observed to be higher along the direction of migration of the contaminant plume than the other areas. The Igeo and CF show decreasing soil pollution down the profile. The EF showed no variation in enrichment pattern with depth. The pollution load index (PLI) was found to be 1.44 and 1.22 at the depths of 1m and 5m respectively, which indicates that the soil is polluted at both depths, yet less polluted down the profile. However, it may be safe to conclude that the aquifer is safe, considering the travel time and also that the pollution of soil at the site decreases with depth.

Effects of additives and sintering temperature on phase evolution and properties of carbon-clay ceramic composites

Fatai Olufemi Aramide,O. D. Adepoju,Abimbola Patricia Popoola 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.6

Effects of additives on phase development and physico-mechanical properties of mullite-carbon was investigated. Powderedclay, kaolinite and graphite of predetermined compositions were blended with additives using ball mill for 3 hrs at 60 rev/min. Samples were produced by uniaxial compression and sintered between 1400 oC and 1600 oC for one hr. They werecharacterized for various properties, developed phases and microstructural features. It was observed that the properties andphase developments in the samples were influenced by the additives. 10 wt % SiC served as nucleating point for SiC around1400 oC. 10 wt % TiO2 lead to development of 2.5 wt % TiC at 1500 oC which increased to 6.8 wt % at 1600 oC. Ifon clay inthe sample leads to development of anorthite and microcline in the samples. 10 wt % TiO2 is effective as anti-oxidant forgraphite up to 1500 oC. Base on strength and absorbed energy, sample C (with 10 wt % TiO2) sintered at 1500 oC is consideredto be optimum.

Anti-leukemic and immunomodulatory effects of fungal metabolites of Pleurotus pulmonarius and Pleurotus ostreatus on benzene-induced leukemia in Wister rats

Akanni E. Olufemi,Alli O.A. Terry,Oloke J. Kola 대한혈액학회 2012 Blood Research Vol.47 No.1

Background The use of natural bioactive compounds in conventional chemotherapy is a new direction in cancer treatment that is gaining more research attention recently. Bioactive polysaccharides and polysaccharide-protein complexes from some fungi (edible mushrooms) have been identified as sources of effective and non-toxic antineoplastic agents. Selected oyster mushrooms (Pleurotus pulmonarius and P. ostreatus being local [Nigeria] and exotic strains, respectively) were cultured on a novel medium of yeast extract supplemented with an ethanolic extract of Annona senegalensis, and the antileukemic potential of their metabolites was studied. Methods Leukemia was successfully induced in Wister rats by intravenous injection (0.2 mL) of a benzene solution every 2 days for 3 consecutive weeks. The aqueous solution of fungal metabolites (20 mg/mL) produced by submerged fermentation was orally administered (0.2 mL) before, during, and after leukemia induction. Leukemia burden was assessed by comparing the hematological parameters at baseline and after leukemia induction. The immunomodulatory potential of the metabolites was assessed by using a phagocytic assay (carbon clearance method). The ability to enhance leukopoiesis was assessed by using the total leukocyte count. Results Leukemia induction resulted in significant anemia indices and leukocytosis (P<0.05) in the experimental rats. Both metabolites equally enhanced leukopoiesis and demonstrated phagocytic actions; P. ostreatus activity was significantly higher than that of P. pulmonarius (P<0.05). Conclusion The metabolites exhibited profound antileukemic potential by suppressing leukemia and demonstrating immunotherapeutic activities on animals after oral administration in various experimental groups.

Hemoglobin F level in different hemoglobin variants

Akanni E. Olufemi,Oseni B. Sola,Bamisaye E. Oluwaseyi,Raji A. Ajani,Mewoyeka O. Olusoji,Hassan R. Olubunmi 대한혈액학회 2011 Blood Research Vol.46 No.2

Background :Fetal hemoglobin (HbF) levels in different hemoglobin variants in Osogbo, Nigeria, were estimated using two principal methods of estimation using existing information for HbF concentration and distribution of various hemoglobin variants in the area, as well as diagnosed cases of thalassemia. Two hundred and sixty samples collected from HbSS, HbSC, HbAA, HbAS, and HbAC subjects were analyzed. HbF level and hemoglobin type were determined in this study. Methods :The hemoglobin type was determined using cellulose acetate electrophoresis at an alkaline pH, and HbF was determined by the acid elution and alkaline denaturation methods. Results :The mean±SD of HbF in the respective hemoglobin variants was as follows: HbSS, 2.09±1.94%; HbSC, 0.85±0.54%; HbAA, 0.69±0.46%; HbAS, 0.52±0.31%; and HbAC, 0.57±0.26%. The mean HbF level across the hemoglobin variants was statistically significant (P<0.05). Investigating the sex distribution of the HbF level in the studied population revealed a slightly higher mean HbF level in females than in their male counterparts. Conclusion :Within the study population, the HbF level was found to be highest in HbSS and lowest in HbAS. The two methods of estimating HbF are equally reliable, since there was no significant difference between the results obtained from the two methods.

Synergistic Action of Virgin Coconut Oil and Clomiphene in Reversing Endocrine Dysregulation in Letrozole-Model of Polycystic Ovarian Syndrome in Rats: Role of Nrf2/HMOX-1 Pathway

Ayodeji J. Ajibare,Olabode O. Akintoye,Ademola C. Famurewa,Moshood A. Folawiyo,Olawande D. Bamisi,Abraham Olufemi Asuku,Oyedoyin Eunice Oyegbola,Christopher O. Akintayo,Babatunde A. Olofinbiyi,Olaposi 한국식품영양과학회 2023 Journal of medicinal food Vol.26 No.9

Polycystic ovarian syndrome (PCOS) is an endocrine disorder in women’s reproductive age. Currently, thepathophysiology of PCOS is unclear, and the limited treatment options are unsatisfactory. Virgin coconut oil (VCO) isfunctional food oil associated with pharmacological effects in reproductive disorders. Therefore, we aimed to evaluatewhether VCO could enhance clomiphene (CLO) therapy against PCOS in female rats. Rats were randomly divided: (1)Control, (2) PCOS model, (3) PCOS + CLO, (4) PCOS + VCO, and (5) PCOS + CLO + VCO. The PCOS was induced viadaily letrozole (1 mg/kg, orally) administration for 21 days. After the PCOS induction, CLO, VCO, and CLO + VCO wereadministered from days 22 to 36. Serum levels of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone(FSH), luteinizing hormone (LH), testosterone, estrogen, progesterone, and prolactin were estimated. Polymerase chainreaction gene expression for nuclear factor-erythroid-related factor 2, heme oxygenase-1 (HO-1), catalase (CAT), glutathionereductase (GSR), LH receptor (LHr), androgen receptor (AR), tumor necrosis factor-alpha (TNF-a), interleukin-1b (IL-1b),and caspase-3 were analyzed. The letrozole-induced PCOS caused considerable increases in GnRH, LH, prolactin, estrogen,and testosterone, whereas FSH decreased significantly compared to the control. The gene expression of Nrf2, HO-1, CAT, andGSR were markedly diminished, while IL-1b, TNF-a, caspase-3, AR, and LHr prominently increased compared to control. Interestingly, the CLO and VCO separately exerted anti-inflammatory and endocrine balance effects. However, VCOenhancedCLO effect in LH, prolactin and testosterone, Nrf2, HO-1, CAT, GSR, and AR. VCO may synergize with CLO todepress hyperandrogenism and oxidative inflammation in PCOS.

Computational optimisation of a concrete model to simulate membrane action in RC slabs

Khandaker M. A. Hossain,Olubayo O. Olufemi 한국계산역학회 2004 Computers and Concrete, An International Journal Vol.1 No.3

Slabs in buildings and bridge decks, which are restrained against lateral displacements at the edges, have ultimate strengths far in excess of those predicted by analytical methods based on yield line theory. The increase in strength has been attributed to membrane action, which is due to the in-plane forces developed at the supports. The benefits of compressive membrane action are usually not taken into account in currently available design methods developed based on plastic flow theories assuming concreteto be a rigid-plastic material. By extending the existing knowledge of compressive membrane action, it is possible to design slabs in building and bridge structures economically with less than normal reinforcement. Recent research on building and bridge structures reflects the importance of membrane action in design. This paper describes the finite element modelling of membrane action in reinforced concrete slabs through optimisation of a simple concrete model. Through a series of parametric studies using the simple concrete model in the finite element simulation of eight fully clamped concrete slabs with significant membrane action, a set of fixed numerical model parameter values is identified and computational conditions established, which would guarantee reliable strength prediction of arbitrary slabs. The reliability of the identified values to simulate membrane action (for prediction purposes) is further verified by the directsimulation of 42 other slabs, which gave an average value of 0.9698 for the ratio of experimental to predicted strengths and a standard deviation of 0.117. A ?eflection factor?is also established for the slabs, relating the predicted peak deflection to experimental values, which, (for the same level of fixity at the supports), can be used for accurate displacement determination. The proposed optimised concrete model and finite element procedure can be used as a tool to simulate membrane action in slabs in building and bridge structures having variable support and loading conditions including fire. Other practical applications of the developed finite element procedure and design process are also discussed.