Omu Aran, Nigeria
Omu Aran, Nigeria

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Owamah H.I.,Landmark University | Izinyon O.C.,University of Benin
Bioresource Technology | Year: 2015

Biogas kinetic models are often used to characterize substrate degradation and prediction of biogas production potential. Most of these existing models are however difficult to apply to substrates they were not developed for since their applications are usually substrate specific. Biodegradability kinetic (BIK) model and maximum biogas production potential and stability assessment (MBPPSA) model were therefore developed in this study for better understanding of the anaerobic co-digestion of food waste and maize husk for biogas production. Biodegradability constant (k) was estimated as 0.11d-1 using the BIK model. The results of maximum biogas production potential (A) obtained using the MBPPSA model were found to be in good correspondence, both in value and trend with the results obtained using the popular but complex modified Gompertz model for digesters B-1, B-2, B-3, B-4, and B-5. The (If) value of MBPPSA model also showed that digesters B-3, B-4, and B-5 were stable, while B-1 and B-2 were inhibited/unstable. Similar stability observation was also obtained using the modified Gompertz model. The MBPPSA model can therefore be used as an alternative model for anaerobic digestion feasibility studies and plant design. © 2015 Elsevier Ltd.

Adebesin B.O.,Landmark University | Adeniyi J.O.,University Of Ilorin | Adimula I.A.,University Of Ilorin | Reinisch B.W.,Lowell Digisonde International, LLC
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2013

Average values of ionosonde hmF2 data acquired from an African equatorial station have been used to determine vertical plasma drift (Vz) measurements during period of low solar activity. Pre-noon peak was around 1000. h LT for all seasons. The peak daytime F2 drift is higher during the equinoctial months with an average of 18.1 m/s than the solsticial months (14.7 m/s). At nighttime, Vz is characterized first by upward enhancement around 1900. h LT with a range of 0.3-8.0. m/s, then by a downward reversal. The highest enhancement was recorded in December solstice and start earliest during the March equinox. The peak reversal values are 13.3, 10.7, 9.0 and 4.2 m/s for December Solstice, September Equinox, March Equinox and June Solstice respectively. The observed simultaneous post-sunset rise in hmF2 and in vertical E× B drift together with a sharp drop in NmF2 at all season infer that electrons moving away from the equator are at a region of low recombination loss rate. The abrupt faster drift of the plasma away from the equator as indicated by the pre-reversal enhancement (PRE) in upward plasma drift is responsible for the sharp drop in NmF2 immediately after sunset. Some past results were also confirmed in this work. © 2013 Elsevier Ltd.

Olufemi Adebesin B.,Landmark University
Indian Journal of Radio and Space Physics | Year: 2012

The present work emphasizes on foF2, the critical frequency of the F2 layer, variations during peak geomagnetic disturbances (Dst ≤ -100 nT) at the rise of solar cycle 23. Geomagnetic, interplanetary and solar wind parameters have been studied as well as foF2 data from five ionosonde stations in the Asian sector. The study shows that: (i) the observed enhancement immediately after sunset at Petropavlovsk compared with foF2 upwelling after sunrise at Magadan after the storm on 12 February 2000 revealed that there is no simultaneity in foF2 during the activity, (ii) the variation of foF2 along a line of fixed latitude, as it occurs at four stations during the 12 August 2000 storm, shows the diurnal anomaly, which depends on the season and epoch of the solar cycle, reaching maximum before sunrise, and (iii) at any latitude, factors other than solar radiance play an important role in determining the foF2 variations. The results seem to agree with earlier works. The morphology of both positive and negative phase storms is also discussed.

Owamah H.I.,Landmark University
Journal of Material Cycles and Waste Management | Year: 2014

The ability of activated carbon from cassava peels to remove heavy metals like Cu(II) and Pb(II) from hospital wastewater was investigated. The study showed that a pH of 8 was the best for the sorption of both metal ions onto the biosorbent. The time-dependent experiments for the metal ions showed that the binding of the metal ions to the biomass was rapid and occurred within 20-120 min. Sorption efficiency increased with a rise in adsorbent dosage. It increased from 12 to 73 % for Pb(II) and 26 to 79 % for Cu(II) when the adsorbent dose increased from 2 to 12 g. An increase in temperature led to an increase in sorption for both metal ions. The Langmuir model showed that the biomass has a higher sorption capacity for Cu(II) than Pb(II), with q m = 5.80 mg g-1 for Pb(II) and 8.00 mg g-1 for Cu(II). The Freundlich isotherm K f was 1.4 for Pb(II) and 1.8 for Cu(II), indicating a preferential sorption of Cu(II) onto the biosorbent. Adsorption capacity was found to decrease with an increase in particle sizes. Sorption occurred by physical mechanisms and was mainly controlled by intraparticle diffusion. © 2013 Springer Japan.

Sojobi A.O.,Landmark University
Environmental monitoring and assessment | Year: 2016

Evaluation of water quality of nine boreholes and three open hand-dug wells in a rural community in North Central Nigeria revealed relative abundance of cations Na > k > Ca > Mg > Zn > Pb and anions Cl(-) > PO4(2-) > SO4(2-) > NO3(-) in the boreholes and cations Ca > Na > K > Mg > Pb and anions NO3(-)  > PO4(2-)  > SO4(2-) > Cl(-) in the wells. The major contaminants exceeding SON and WHO permissible limits were NO3(-) , Mg, TH, pH and Mg, Pb, TH, pH and DO in the wells and boreholes, respectively. They are attributable to anthropogenic sources such as domestic waste water and poor waste disposal and natural sources such as mineral dissolution from clayey aquifer which made the acidic groundwater unsuitable for consumption unless they are appropriately treated. Correlation studies revealed existence of three major mineral groups in the aquifer Ca-Fe group, Na-Mg group, Zn-K group, as well as a minor group Pb-group, and they determine the chemical composition of the groundwater and the ionic exchange between the groundwater and mineral-bearing clayey aquifer. In order to curb microbial contamination by Enterobacter aerogenes and Escherichia coli, it is recommended that proper latrines and drainages be provided while domesticated animals should be restricted from boreholes and well. Further, treatment with water guard and pur purifier is recommended.

There is paucity of information on quality and cheap feedstuffs for snail production in the Tropics. The performance, nutrient digestibility, carcass analysis and organoleptic qualities of snailets of Archachatina marginata fed diets containing graded levels of dried lettuce (DL) were assessed in a 20 week trial. 180 snailets with average weight of 9.18 ± 2.67 g were allotted to 4 diets of 45 snailets per treatment and each treatment replicated thrice with 15 snails per replicate. Snailets were randomly distributed into 4 dietary treatments consisting of 0% DL(T1), 25%DL(T2), 50%DL(T3) and 100%DL(T4) with DL replacing maize in a completely randomized design. Water and feed were presented ad libitum while feed intake and weight gain were measured on daily and weekly basis respectively. Shell length and width were measured with vernier caliper while shell thickness was measured with a micrometer screw gauge on weekly basis. The body weight gain, feed per gain and nutrient digestibility of snailets on T1, T2 and T3 were similar, higher and significantly different (P < 0.05) from those of snailets on T4. The dressing percentages in all the treatments were similar. The organoleptic assessment revealed that the dietary treatments had no significant effect (P > 0.05) on the color, taste, flavor, texture and overall acceptability of the snail meat. Snailets on diet T3 were the best in terms of economy of production by having a feed cost savings of 9.16% when compared with the control diet with no dried lettuce. In conclusion, it can be stated that diet T3 containing 50% DL replacement for maize was the best in terms of performance, nutrient digestibility and economy of production amongst the tested diets. © 2016 Elsevier B.V.

Betiku E.,Obafemi Awolowo University | Adepoju T.F.,Landmark University
International Journal of Energy and Environmental Engineering | Year: 2013

Statistical approach was employed to optimize biodiesel production from sesame oil in this work. Precisely, response surface methodology was applied, and the effects of four variables, viz. reaction temperature, catalyst amount, reaction time, and methanol/oil molar ratio, and their reciprocal interactions were determined. Central composite rotatable design was used to generate a total of 30 individual experiments, which were designed to study the effects of these variables during alkali-catalyzed methanolysis of sesame oil. A statistical model predicted the highest conversion yield of sesame biodiesel to be 99.71% at the following optimized variable conditions: reaction temperature of 63°C, catalyst amount of 1.04 wt.%, and methanol/oil molar ratio of 6.24, with a reaction time of 51.09 min. Using these variables under experimental condition in four independent replicates, an actual biodiesel yield of 98.36% was accomplished. The fuel properties of biodiesel produced were found to be within the ASTM D6751 and DIN EN 14214 biodiesel specifications. © 2013 Betiku and Adepoju.

Adeyemi O.S.,Landmark University | Sulaiman F.A.,University Of Ilorin
Journal of Biomedical Research | Year: 2015

Diminazene aceturate is a trypanocide with unwanted toxicity and limited efficacy. It was reasoned that conjugating diminazene aceturate to functionalized nanoparticle would lower untoward toxicity while improving selectivity and therapeutic efficacy. Silver and gold nanoparticles were evaluated for their capacities to serve as carriers for diminazene aceturate. The silver and gold nanoparticles were synthesized, functionalized and coupled to diminazene aceturate following established protocols. The nanoparticle conjugates were characterized. The free diminazene aceturate and drug conjugated nanoparticles were subsequently evaluated for cytotoxicity in vitro. The characterizations by transmission electron microscopy or UV/Vis spectroscopy revealed that conjugation of diminazene aceturate to silver or gold nanoparticles was successful. Evaluation for cytotoxic actions in vitro demonstrated no significance difference between free diminazene aceturate and the conjugates. Our data suggest that surface modified metal nanoparticles could be optimized for drug delivery systems. © 2015 by the Journal of Biomedical Research.

Adeniyi J.O.,University Of Ilorin | Ikubanni S.O.,Landmark University
Advances in Space Research | Year: 2013

By introducing the two-segmented linear regression model instead of the well known quadratic fit, we were able to describe the solar activity dependence of the F2 critical frequency. Saturation features were observed and the corresponding F10.7 values at which this phenomenon occurs were obtained for different hours. The seasonal average values were found to be around 154 sfu, 138 sfu, 177 sfu and 150 sfu for March equinox, June solstice, September equinox and December solstice respectively. These affirmed that saturation phenomenon is more pronounced at the equinoxes than solstices. On the average, the threshold value of F10.7 was obtained to be 154.5 sfu for this station in the African sector of the equatorial region. © 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.

Ikubanni S.O.,Landmark University | Adeniyi J.O.,University Of Ilorin
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2013

Saturation in the dependence of foF2 on solar flux is a phenomenon more pronounced in the equatorial ionization anomaly region. The phenomenon was observed in the relationship between the F2 critical frequency (foF2) and any solar indices. Using a two-segmented regression fit on data from an African low latitude station (Geographical Latitude 12.4°N; Geomagnetic latitude 3.5°N), saturation features from the dependence of foF2 on solar radio flux (F10.7) was studied. Diurnal and seasonal variation were studied for the first time in this low latitude region of the African sector. Significant variations were observed, especially in the solstices. It was observed that saturation effect is closely related to the hourly F2 critical frequency and these results were compared with those from Asian, Australian and the American sectors. The diurnal and seasonal variations find their explanations in the photo-ionization process, the fountain effect, and the pre-reversal enhancement while the seasonal variation was attributed to both the ion drift and thermospheric circulation. Future work with larger volume of data is expected to validate the observations from this study. © 2013 Elsevier Ltd.

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