Civil Engineering

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Atmospheric modeling and integration between meteorology and hydrology
(GLOWA, 2002-04) D Burose,; Friesen, J.; Intsiful, J.; Jung, G.; Kunstmann, H.; Moene, A.; Oguntunde, Philip G.; Van de Giesen, N.
Understanding feedback mechanisms between atmosphere and land surface is crucial for predicting impact of global change on the regional hydrological cycle. Unfortunately, meteorological models have different scales than hydrological land surface models, which hinders feedback analysis. Results from innovative field measurements (scintillometry) are presented that help integrate hydrology and meteorology by bridging this scale gap. Subsequently, the operationalization of the MM5 meteorological model is described. Numerical experimentation with MM5 shows that changes in land surface properties do have large feedback effects on regional circulation patterns.
Effects of charcoal production on maize yield, chemical properties and texture of soil
(Biology and Fertility of soils (Springer-Verlag), 2004-03) Oguntunde, Philip G.; Fosu, Matthias; Ajayi, Ayodele E.; Van de Giesen, Nick
The effects of charcoal production on soil textural and chemical properties were investigated in Ejura, Ghana. The aim was to study the effects of heating and charcoal residue on maize yield, soil texture and soil chemical properties. Composite samples were taken from the 0–10 cm layer of soil at charcoal-making sites and from adjacent fields (control). Twelve sites were randomly selected for the study across the range of the Kotokosu watershed. Maize was planted in four selected locations on charcoal site soils (CSS) and adjacent field soils (AFS) to assess the impact of charcoal production on crop yield. There was a significant increase in soil pH, base saturation, electrical conductivity, exchangeable Ca, Mg, K, Na and available P in the soil at the kiln sites as compared to the adjacent soils. A relative change of up to 329% was observed in K while organic C and total N decreased by 9.8% and 12.8%, respectively. Organic C and total N were highly correlated ( P <0.01) and both parameters significantly ( P <0.05) depended on clay minerals in the soils. Soil texture was also modified with a significantly higher sand content and lower clay fraction in the CSS. The grain and biomass yield of maize increased by 91% and 44%, respectively, on CSS as compared to AFS. Further research to ascertain the longterm effects of charcoal production on the soil environment and the fertility of tropical soils is needed. Keywords Charcoal production · Soil heating · Soil fertility · Maize yield · Ghana
Water flux in a cashew orchard during a wet-to-dry transition period: analysis of sap flow and eddy correlation measurements
(Earth Interactions, 2004-11) Oguntunde, Phillip G.; Van de Giesen, N.C.; Vlek, P.L.G.; Eggers, H.
Information regarding biosphere–atmosphere interactions is important in the study of a hydrological cycle. To this purpose, xylem sap flow (SF) using the Granier system and evapotranspiration (ET) using the eddy * Corresponding author address: Philip G. Oguntunde, Center for Development Research (ZEF), University of Bonn, Walter Flex Str. 3, 53113 Bonn, Germany. E-mail address: poguntun@uni-bonn.de Earth Interactions Volume 8 (2004) Paper No. 15 Page 1 Unauthenticated | Downloaded 03/05/26 02:17 PM UTC correlation method were measured during a ‘‘wet-to-dry’’ transition period in a young cashew (Anacardium occidentale L.) plantation. Estimates of half-hourly tree transpiration made from stem sap flow measurements and above-canopy eddy correlation measurements of water vapor flux were compared for a period of 22 days of complete records. Cross-correlation analysis was used to estimate the time lags (s) between the time courses of SF and ET, and between SF and ET with solar radiation (RS) and vapor pressure deficit (D). Applying a simple functional technique, values of s¼43 min (November), s¼46 min (December), and s¼75 min (January) with an overall s¼53 min (using all data) between the time courses of ET and SF were estimated. A positive lag indicates that SF lags behind ET. However, both ET and SF were more dependent on RS (r 2 . 0.81) than on D, whereas SF was more related to D (r 2 ¼ 0.60) compared to ET (r 2 ¼ 0.38). An insignificant (p . 0.05) decrease in daily values of both ET and SF over the 22 days of concurrent measurements were observed. Daytime average ET ranged from 2.01 to 3.17 mm day1 with a mean of 2.7 mm day1 , whereas values of SF ranged from 0.55 to 0.72 mm day1 with a mean of 0.65 mm day1 . Tree transpiration accounted for about 25% of the evapotranspiration from the orchard. This result may be of help in correctly predicting the diurnal behavior of transpiration from sap flow measurements.
A semi-empirical model for estimating surface albedo of wetland rice field
(International Commission of Agricultural Engineering, 2007) Oguntunde, Phillip G.; Olukunle, O.J.; Ijatuyi, O.A.; Olufayo, A.A.
Surface albedo plays a vital role in the evapotranspiration component of the wetland rice water balance. This paper examines the influence of the phenological stages of rice (Oriza sativa) field on observed albedo at a tropical site (Ghana) during the year 2002, with a view to parametrizing a simple albedo model suitable for inclusion in models to estimate evapotranspiration in wetland rice cropping systems. Crop management was similar for the two planting dates used in this study. Measurements were taken from 10 m x 10 m plots within rice fields. Four phenological stages were distinguished: emergence, vegetative, flowering and physiological maturity. Surface albedo (α) was measured and simulated, using a calibrated semi-empirical model, at solar zenith angles of 15°, 30°, 45°, 60°, and 75°. Leaf area index (LAI) and crop height (h) were also monitored. Generally, albedo increases from emergence to flowering for both planting dates but slightly decreases after flowering. The correlation coefficient (r) between α and LAI equals 0.985 and the correlation coefficient between α and h equals 0.908. The composed albedo model adequately predicted the observed albedos with an overall r = 0.946 and mean bias error (MBE) of 0.002. The extinction coefficient of the rice crop albedo was estimated as 0.75. Data presented are valuable inputs in agricultural water management, rice production models, and especially as vital sub-routine inputs in calculating evaporation and transpiration from wetland rice.
Environmental regulation and modelling of cassava canopy conductance under drying root‐zone soil water
(John Wiley & Sons, Ltd., 2007-09) Oguntunde, Phillip G.; Alatise, Michael O
Sap flow was measured, with Granier-type sensors, in a crop of field-grown water-stressed cassava (Manihot esculenta Crantz) in Ghana, West Africa. The main objective of this study was to examine the environmental control of canopy conductance (gc) with a view to modelling the stomatal control of water transport under water-stressed condition. Weather variables measured concurrently with sap flow were: air temperature (Ta ), relative humidity (RH ), wind speed (u) and solar radiation (Rs). Relationship between canopy conductance (gc) and vapour pressure deficit (Dε) was curvilinear while no specific pattern was observed with Rs. Average diurnal gc decreased from 3.0 ± 0.6 to 0.7 ± 0.4 mm s−1 between 0730 and 2000 h local time (= GMT) each day. A Jarvis-type model, based on a set of environmental control functions, was parameterized for the cassava crop in this study. Model results demonstrated that gc was estimated with a high degree of accuracy based on Rs, Ta , and Dε (r2 = 0.92; F = 809.2; P < 0.0001). Dε explained about 90% (F = 2129.7;P < 0.0001) of the variations observed in gc, whereas both Rs and Ta contributed about 2% of the explained variance in gc. The aerodynamic conductance (ga ) was very high compared to gc, leading to a daily average ratio ga /gc > 100 and a decoupling factor< 0.1. Cross-validation analysis revealed a consistent good performance (r2 > 0.85) of the gc model with Dε as the only independent environmental variable. Copyright  2007 Royal Meteorological Society
Hydrotope-based protocol to determine average soil moisture over large areas for satellite calibration and validation with results from an observation campaign in the Volta
(IEEE, 2008-05-16) Friesen, Jan; Rodgers, Charles; Oguntunde, Philip G.; Hendrickx, Jan M.H.; Giesen, Nick van de
In West Africa, which is an extremely moisturelimited region, soil water information plays a vital role in hydrologic and meteorologic modeling for improved water resource planning and food security. Recent and upcoming satellite missions, such as SMOS and MetOp, hold promise for the regional observation of soil moisture. The resolution of the satellites is relatively coarse (> 100 km2 ), which brings with it the need for large-scale soil moisture information for calibration and validation purposes. We put forward a soil moisture sampling protocol based on hydrotopes. Hydrotopes are defined as landscape units that show internally consistent hydrologic behavior. This hydrotope analysis helps in the following ways: 1) by ensuring statistically reliable validation via the reduction of the overall pixel variance and 2) by improving sampling schemes for ground truthing by reducing the chance of sampling bias. As a sample application, we present data from three locations with different moisture regimes within the Volta Basin during both dry and wet periods. Results show that different levels of reduction in the overall pixel variance of soil moisture are obtained, depending on the general moisture status. With respect to the distinction between the different hydrotope units, it is shown that under intermediate moisture conditions, the distinction between the different hydrotope units is highest, whereas extremely dry or wet conditions tend to have a homogenizing effect on the spatial soil moisture distribution. This paper confirms that well-defined hydrotope units yield an improvement at pixel-scale soil moisture averages that can easily be applied.
Calibration and validation of a soil water simulation model (WaSim) for field grown Amaranthus cruentus
(International Journal of Plant Production, 2008-07-01) Fasinmirin, JT; Olufayo, AA; Oguntunde, Phillip G.
A water simulation model (WaSim) to simulate the growth and development of Amaranthus cruentus as well as the components of water balance for a typical sandy-clay-loam soil of Akure has been described. Dry season experiments were carried between January and March of 2005 and 2006. Amaranthus seeds were established on the field and three irrigation water managements were imposed on the crop to determine its response to water deficit at its different phenological stages. Amaranthus growth and development, evapotranspiration (ET) and rooting depth were calibrated by fitting the most sensitive variables to obtain the corresponding model output. The model simulated crop growth and crop cover well, the coefficient of determination r2 =0.9 and the difference between simulated and measured root depth is not significant at P<0.001. The actual evapotranspiration (AET) from the model prediction and the measured value gave a fairly high coefficient of correlation r=0.7 at P<0.001. The mean bias error (MBE) and the root mean square error of yield estimates between the measured and the model prediction are -0.4444 and 1.35 respectively at P < 0.001. The model was considered effective and appropriate for daily simulation of water balance, water requirement of crops and in climate effects on crop production.
Effects of charcoal production on soil physical properties in Ghana
(WILEY‐VCH Verlag, 2008-08) Oguntunde, Philip G.; Abiodun, Babatunde J.; Ajayi, Ayodele E.; Van De Giesen, Nick
Charcoal production, widespread in Ghana like in other W African countries, is a major driver of land-cover change. Effects of charcoal production on soil physical, including hydrological, properties, were studied in the forest–savannah transition zone of Ghana. Core and composite samples from 12 randomly selected sites across the width of Kotokosu watershed were taken from 0–10 cm layer at charcoal-site soils and adjacent field soils (control). These were used to determine saturated hydraulic conductivity (Ksat), bulk density, total porosity, soil texture, and color. Infiltration rates, surface albedo, and soil-surface temperature were also measured on both sites. The results showed that the saturated hydraulic conductivity of soils under charcoal kilns increased significantly (p < 0.01) from 6.1 ± 2.0 cm h–1 to 11.4 ± 5.0 cm h–1, resulting to a relative increase of 88%. Soil color became darkened under charcoal kilns with hue, value, and chroma decreasing by 8%, 20%, and 20%, respectively. Bulk density on charcoal-site soils reduced by 9% compared to adjacent field soils. Total porosity increased from 45.7% on adjacent field soils to 50.6% on earth kilns. Surface albedo reduced by 37% on charcoal-site soils while soil-surface temperature increased up to 4°C on average. Higher infiltration rates were measured on charcoal-site soils, which suggest a possible decrease in overland flow and less erosion on those kiln sites. Keywords: charcoal production / soil physical properties / Ksat / infiltration rates / reflection coefficient / watershed hydrology
Water use efficiency of Manihot esculenta crantz under drip irrigation system in south western Nigeria
(European Journal of Scientific Research, 2009) Olanrewaju, O.O.; Olufayo, A.A.; Oguntunde, Phillip G.; Ilemobade, A.A.
Field experiments was conducted at Teaching and Research Farm, Federal University of Technology, Akure between November 2006 and November 2007 to find out the water use efficiency under drip irrigation system and effect on the growth and yield of Cassava (Manihot esculenta Crantz). A popular hybrid of cassava TMS 30572 was tried as a test crop. The soil of the experimental site was moderately drained, loamy sand. The experiments were laid out in a 4 X 4 X 2 randomised complete block design (RCBD) consisting of 4 treatments, 4 replicates and 2 varieties using a spacing of (1m x 0.8m) for mechanical harvesting. The results indicated that the highest moisture content was recorded at depth of 40cm during the late stage of tuber development and the highest biomass yield was recorded under full irrigation treatment than in other treatments. The yield of cassava ranged from 21.87 to 14.13 t ha-1 in all the treatments except for the control that has 8.45 t ha-1 while the water use efficiency ranged from 19.18 to 23.63 kg ha-1mm. Irrigation through full treatment registered the highest mean tuber yield of 21.87 t ha-1 while the least tuber yield was associated with the control treatment. The height and stem diameter of cassava also responded higher under full treatment of available water. This study demonstrated that medium irrigation (60% AW) could be best option in terms of water efficiency. Water Use Efficiency of Manihot Esculenta Crantz Under Drip Irrigation System in South Western Nigeria
Influence of Tree Age and Variety on Allometric Characteristics and Water Use of Mangifera indica L. Growing in Plantation
(Hindawi Publishing Corporation, 2011-09-22) Oguntunde, Philip G.; Fasinmirin, Johnson T.; Van de Giesen, Nick
Mango (Mangifera indica L.), a diffuse-porous species and one of the most important tropical tree crops [1], belongs to the family Anacardiaceae [2]. It is believed that mango was brought from Arabia to Africa in the first millennium AD [3]. Ghana received more than a dozen cultivars in the early 1920s and more than a dozen other cultivars were brought in later from Florida and India [2]. However, because of identification problems, an effort was initiated in 1967 to classify the seedlings in the Ejura district, the Ejura Agricultural Station, and the plantation of the Faculty of Agriculture, University of Science and Technology, Kumasi, in order to eliminate confusions and have identifiable cultivars marked for future research. There is great potential for the rapid growth of mango industry in West Africa if the current planting rate and government encouragements are sustained. Although mango is drought tolerant and could be conveniently cropped under rain-fed conditions, supplemental irrigation may be required for optimising growth, fruit set, and yield [4]. Poor and unreliable flowering is one of the factors leading to low productivity [5], but applying irrigation from peak flowering to fruit maturity could induce reliable flowering leading to high yield [6, 7]. Preflowering irrigation was reported to increase the overall photosynthetic activity of the tree at the time of flowering [8]. The necessity to directly and continuously monitor water use for precise irrigation scheduling in mango plantations has been reported [4, 7]. Subsequently, a Granier sap flow measurement method was evaluated and applied successfully to measure sap flow per unit sapwood area in young to mature mango trees. Despite current advances, especially in Australia, there is little or no information regarding water use of mango trees in West Africa. In the study area, the planting practices have resulted in age differences of adjacent plantations coupled with indiscriminate mixtures of varieties or cultivars. These lead to differences in cultivars composition on different stands. Previous studies reported that young/mature trees use more water per unit sapwood area than old trees of the same species in a similar environment due to changes in stem and branch hydraulics with age [9, 10] as well as pressure gradient due to gravity [11]. The objectives of this study were 2 Journal of Botany to examine the degree to which differences in tree age and variety mixture affect water use and allometric characteristics of mango trees under subhumid tropical environment of West Africa. The study was part of the just concluded GLOWA Volta project (http://www.glowa-volta.de/), which lasted between 2000 and 2009. In the context of this project, designed to study “sustainable water use under various land use change and rainfall reliability,” understanding the hydrological process in the basin water balance is very important. Determinations of water use from each component of ecosystem vegetation were required and therefore partly motivated this study
Rainfall trends in Nigeria, 1901–2000
(Elsevier (Journal of Hydrology), 2011-12-09) Oguntunde, Philip G.; Abiodun, Babatunde J.; Lischeid, Gunnar
There is the need to evaluate changes in the spatial and temporal patterns of rainfall in order to improve water management strategies of a given region. In this study, standard tests are used to examine the existence of trend in annual and monthly rainfall of Nigeria over the last century. Rainfall variability index was estimated as standardized rainfall departure while autocorrelation spectral analysis is used to obtain the periodicities inherent therein. Rainfall spatial distribution was highly latitudinal dependent (r2 > 0.90) and had no clearly linear relations with the longitude. Rainfall variability index showed that 1950s was the wettest decade (+0.84) while 1980s was the driest (−1.19), with the two decades between 1970 and 1990 being drier than any other comparable period in the last century. Observed rainfall changes varied between −3.46 and +0.76 mm yr−2. About 90% of the entire landscape exhibited negative trends but only 22% showed significant changes at 5% level. There was a sharp difference between changes in rainfalls in 1931–1960 and 1961–1990 periods. Annual precipitation reduced by 7% between the two periods. While more than 90% of the landscape showed no significant rainfall change in the first period, about 57% of Nigeria showed a significant (P < 0.05) decrease in the second. The dominant peaks can be classified into four distinct rainfall cycles with periods 2–3, 5–7, 10–15 and 30 yr. These cycles may be associated with the stratospheric Quasi-Biennial Oscillation (QBO), the El-Nino Southern Oscillation (ENSO); the sunspot cycles and the Atlantic Multi-Decadal Oscillation (AMO) sea surface temperature, respectively.
Crop Water Productivity of Plantain (Musa Sp) in a Humid Tropical Environment.
(JOURNAL OF Engineering Science and Technology Review, 2012-01-01) Akinro, A.O.; Olufayo,A.A.; Oguntunde, Phillip G.
Crop water productivity defines the relationship between crop produced and the amount of water involved in producing the crop. It is a useful indicator for quantifying the impact of irrigation scheduling decisions with regard to water management. This paper presents CWP quantified from field experimental data. The field experiments were conducted for three years in a tropical region of south Western Nigeria to determine the crop water productivity (CWP) and consumptive use of plantain (musa sp) cv. Agbagba. There were four treatments and four replicates based on the level of water application. CWP were computed in terms of crop water use, water applied, and economic returns. Results showed that crop water consumed varied significantly (P<0.05) among treatments. Estimated water consumed ranged from 900 mm to 1700 mm from planting to harvest depending on the irrigation water regime. Crop Water Productivity (CWP) in terms of water consumed varied from 0.91 – 1.37 kgm-3 for 2006/2007 and 0.91 – 1.41 kgm-3 in the 2007/2008 seasons respectively while CWP in terms of water applied varied from 2.82 – 3.98 kgm-3 and 2.89 – 4.04 kgm-3 in the first and second seasons respectively. The amount of irrigation water applied at the different growth stages of the crop and the growth stage response to moisture stress influenced the status of CWP. The findings indicated that plantain crops were very sensitive to lack of soil water during the total growing season.
Re-examination of the BMN model for estimating evapotranspiration
(Scientific and Academic Publising (http://journal. sapub. org/ijaf), 2012-02-06) Ilesanmi, Oluwaseun Ayodele; Oguntunde, Phillip G.; Olufayo, Ayorinde A.
y re-examined the BMN model making use of the Sigma Plot software (based on the Levenberg – Marquardt algorithm) to generate modified versions of the BMN model that are specific for Ibadan, Kano and Onne and one version which applicable across the country, correcting some perceived shortcomings of the BMN. Records of climatic variables (Solar radiation, Maximum and Minimum Temperature, Maximum and Minimum Relative Humidity and Wind speed) were collected from three International Institute of Tropical Agriculture (IITA) Stations in Ibadan, Kano and Onne. For Ibadan, a 36-year (1973 – 2008) record was obtained, for Kano, a 29-year (1980 - 2008) record was obtained and for Onne, a 31-year (1977 - 2006) record was obtained. Evapotranspiration rates for each of the stations were then estimated using the FAO56-PM model. ETo estimates from the FAO56-PM model were thereafter used to recalibrate the BMN model, generating new model constants for Ibadan, Kano, Onne and a model combining the climatic characteristics of the three stations. The re-calibrated BMN model had higher correlation values of 0.74, 0.79 and 0.75 for Ibadan, Onne and Kano respectively when compared with the FAO-56 model than the Original BMN model when compared with the FAO56-PM model with values of 0.7, 0.77 and 0.75 respectively for Ibadan, Onne and Kano.
Rainfall variability at regional and local scales in the Ouémé upper valley in Benin
(International Journal of Science and Advanced Technology, 2012-06) Lawin, Emmanuel Agnidé; Afouda, A.; Oguntunde, Phillip G.; Gosset, M.; Lebel, T.
In West Africa, many climatic simulations show that significant changes to deal with will be exacerbation of climatic extremes (droughts, floods etc.). In the case of the Ouémé Upper Valley region where agricultural activities are essentially dependent on precipitations, it’s important to analyze impacts of climate fluctuations on the rainfall pattern. Two spatial scales have been considered to access the rainfall pattern variability in that region: especially the regional one and the local one. A seasonal rainfall analysis has been made with observed or regionalized daily rainfall data for 1950-2005 period. Dry and wet composite analysis of the rainfall signal shows that the pluviometric shortage of dry years is amplified after the “monsoon onset”. On the same way, dry years are characterized by early monsoon withdrawal which might have started since 1970. Furthermore, the years after 1970 show a shift lag in rainfall. The length of these lags depends on spatial scale. Rainfall maximum are earlier observed. The early monsoon withdrawal and the shift lag in rainfall revealed should have several consequences on agricultural production, especially on some crops yield.
Implications of trends and cycles of rainfall on agriculture and water resource in the tropical climate of Nigeria
(Special Publication of the Nigerian Association of Hydrological Sciences., 2012-08-11) Alli, AA; Oguntunde, Phillip G.; Olufayo, AA; Fasinmirin, JT
Trends and cycles of rainfall over Nigeria, as well as their implications for water resources and agriculture, have been studied since 1960 on annual, seasonal and monthly bases. Rainfall data of 47 years (1960 – 2006) were obtained for twenty stations over Nigeria for the evaluation of trends using the Mann-Kendall test. Auto correlation spectral analysis was also used to detect cycles of rainfall. The result showed dominant peaks in rainfall return at various rates. For instance, Akure, Benin, Calabar, Maiduguri and Yola stations had decreasing trends of annual rainfall at rates of 1.084, 0.03, 1.80, 0.75, and 0.12 mm/month/yr, respectively with return periods between 1-2 years and 7-10 years. Rainfall trends increased in about 75 % of the locations with return period of dominant peaks varying between 1-2 years and 15 years. Abuja recorded the highest peak of rainfall in the month of October at the rate of 4.7 mm/month/yr with return period of 1-2 years. These results indicate different spatial effects on ecosystem and agriculture. Some of the implications of these trends on agriculture and water resources vary from one station to another, depending on the trends and magnitude of return period of rainfalls. Bauchi and Minna cities are expected to experience serious desertification and complete depletion of underground water due to the effects of no change in trend of rainfall. Meanwhile, agricultural activities are expected to thrive in places like Ibadan, Gusua, Osogbo and others that have moderate increase in trends of rainfall and temperature.
Performance of the SunScan canopy analysis system in estimating leaf area index of maize
(CIGR Journal, 2012-09-23) Oguntunde, Phillip G.; Fasinmirin, Johnson T; Abiolu, Oluremi A
Rapid and reliable estimates of leaf area index (LAI) are important for studies of exchanges of energy and gases in the biosphere-atmosphere continuum. This paper evaluates the field performance of SunScan canopy analysis system for rapid estimation of LAI. Direct and indirect measurements of LAI were made in a maize (Zea mays L.) field at four phenological stages (emergence, vegetative, flowering and physiological maturity) at a tropical site in Ghana during the Glowa Vota Project field campaign (www.glowa-volta.de). Similar measurements were repeated in early and late planting seasons with similar crop management practices. The result showed a generally good performance of this sensor at all the phenological stages. Average LAI from the sensor (LAIS ), ranged from 0.40–4.45, and was consistently higher than the actual LAI, which varied from 0.31–4.22, respectively for both seasons. Regression between LAI and LAIS showed a range of significant correlations with R2 > 0.74 for all the stages and seasons. With combined datasets for all stages and the two plantings, a simple regression model was fitted to estimate LAI from LAIS with R2 = 0.97 and standard error of 0.23 (P < 0.0001). The evaluated sensor yielded a good and reliable LAI estimates under maize canopy.
Quality assessment of Sandcrete blocks in Ibadan – A review
(Epistemics in Science Engineering and Technology, 2013) Adeniji, Akintayo A.; Ganiyu, A. A.; Ajagbe, W. O.
Sandcrete blocks have been widely used for modern building construction in Nigeria; however cases of incessant building collapse are rampant. The usage of substandard sandcrete blocks is a contributing factor. This research was carried out to assess the engineering properties of sandcrete blocks produced in Ibadan and its environs. Two blocks each of size 450 x 225 x 225mm were purchased from selected block industries at eight sampled locations within the study area. Few units of blocks (450 x 225 x 225mm) conforming to the Nigerian Industrial Standard (NIS 87: 2007) were also produced to serve as control samples. The 28th day dry compressive strength test result obtained for the sampled blocks ranges between 0.39-2.34 N/mm2. For the control block samples, the average 28th day dry compressive strength of the three tested blocks was 3.02 N/mm2. Conclusively, it was observed that the sandcrete blocks produced in major parts of Ibadan were of low quality and substandard; while the control samples were of adequate strength.
Evaluation of Four ETo Models for IITA Stations in Ibadan, Onne and Kano, Nigeria.
(Journal of Environment and Earth Science, 2014) Ilesanmi, Oluwaseun A.; Oguntunde, Phillip G.; Olufayo, Ayorinde A.
Records of climatic variables (Solar radiation, Maximum and Minimum Temperature, Maximum and Minimum Relative Humidity and Wind speed) were collected from three International Institute of Tropical Agriculture (IITA) Stations namely Ibadan, Kano and Onne in Nigeria. For Ibadan, a 36-year (1973 – 2008) record was obtained, for Kano, a 29-year (1980 - 2008) record was obtained and for Onne, a 31-year (1977 - 2006) record was obtained. Evapotranspiration rates for each of the stations were estimated using the FAO-56 approach. The performance of four ET models (Blaney-Morin-Nigeria (BMN), Hargreaves-Samani, Priestly-Taylor and JensenHaise models) were evaluated with reference to FAO 56 Model making use of ET estimated from these models. The BMN model was found out to be the best model that can be applied to estimate ET in each of these stations because it has a high correlation value with the values obtained from FAO56-PM model along with favourable statistic values and it requires a considerably less number of variables for its estimation with correlation (r) values of 0.7, 0.77 and 0.75 respectively for Ibadan, Onne and Kano
SIMULATION AND MODELING OF A CARBURIZING PROCESS USING VARIABLES FOR EFFECTIVE PERFORMANCE IN SERVICE IN AISI 1032 STEEL
(The American Ceramic Society, 2015) Adegbola, Adekunle; Akeem, Ghazali; Alabi, Ismaila; Kareem, Mutiu
The mechanical properties of AISI 1032 steel samples carburized in Wood Charcoal and Snail Shell were investigated. The samples were modeled and simulated using Fick’s law and C++, in order to evaluate the performances of solid carburizing media on the mechanical properties of steels at different conditions. The results revealed that the case depth, tensile strength and hardness values of samples carburized with Wood Charcoal (WChl) are higher compared to those carburized with Snail Shell (SS) at 800 0C and 950 0C respectively. These were evidently substantiated with their micrographs as observed under DV-500 Version 10.2 Metallurgical Microscope with X500 magnification. The case-depth is directly proportional to the carburized temperature and time. It was concluded that Fick’s law is good at predicting the diffusion of carbon in steels.
Numerical Simulation of Temperature Distribution in A Tri-Cycle Engine Piston
(International Journal of Scientific & Engineering Research,, 2015-06) Alabi, Ismaila Olanrewaju; Adesina, Olaiya Kamorudeen; Olalekan, Kareem Mutiu
Pistons as one of the most complex components among all automotives and other industry field components are de-signed to withstand damage caused due to extreme heat and pressure of combustion process. Many of experimental studies regarding the internal combustion engines process have been carried out, but few had only focused on the numerical studies like stress distribution, thermal and heat transfer analysis. This present study focuses on a 3-D transient state temperature dis-tribution analysis on a gasoline piston model of a tri-cycle. Mathematical model was formulated, solved and simulated using a Finite Element Method (FEM) in-built in the COMSOL Multiphysics software 4.3a to determine the temperature distribution and gradient of the piston model ranging from 523K – 673K. The parameters used for the simulation were liquid (Gasoline), Gases (Air) and Aluminium alloy UNSA96061 (Piston). The Completed mesh tetrahedral consists of 86225 elements and the number of degrees of freedom solved for were 18553 in 367 s (6 minutes, 7 seconds) in the mesh optimization. It was discovered from the results obtained that the temperature in the combustion chamber of the tricycle engine varies with respect to time, along the pis-ton.The transient analysis from the time dependent solver revealed that the temperature of the piston at the TDC (Top Dead Centre) in the first power stroke is higher compared to the subsequent power strokes, which is an indication that more heat was transfer at subsequent power strokes. Probable recommendations were later made.

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