3D Post-stack Seismic Inversion using Global Optimization Techniques: Gulf of Mexico Example

Seismic inversion using a global optimization algorithm is a non-linear, model-driven process. It yields an optimal solution of the cost function – reflectivity/acoustic impedance, when prior information is sparse. The inversion result offers detailed interpretations of thin layers, internal stratigraphy, and lateral continuity and connectivity of sand bodies. This study compared two stable and robust global optimization techniques, Simulated Annealing (SA) and Basis Pursuit Inversion (BPI) as applied to post-stack seismic data from the Gulf of Mexico. Both methods use different routines and constraints to search for the minimum error energy function. Estimation of inversion parameters in SA is rigorous and more reliable because it depends on prior knowledge of subsurface geology. The BPI algorithm is a more robust deterministic process. It was developed as an alternative method to incorporating a priori information. Results for the Gulf of Mexico show that BPI gives a better stratigraphic and structural actualization due to its capacity to delineate layers thinner than the tuning thickness. The SA algorithm generates both absolute and relative impedances, which provide both qualitative and quantitative characterization of thin-bed reservoirs

3D Post-stack Seismic Inversion using Global Optimization Techniques: Gulf of Mexico Example

Seismic inversion using a global optimization algorithm is a non-linear, model-driven process. It yields an optimal solution of the cost function – reflectivity/acoustic impedance, when prior information is sparse. The inversion result offers detailed interpretations of thin layers, internal stratigraphy, and lateral continuity and connectivity of sand bodies. This study compared two stable and robust global optimization techniques, Simulated Annealing (SA) and Basis Pursuit Inversion (BPI) as applied to post-stack seismic data from the Gulf of Mexico. Both methods use different routines and constraints to search for the minimum error energy function. Estimation of inversion parameters in SA is rigorous and more reliable because it depends on prior knowledge of subsurface geology. The BPI algorithm is a more robust deterministic process. It was developed as an alternative method to incorporating a priori information. Results for the Gulf of Mexico show that BPI gives a better stratigraphic and structural actualization due to its capacity to delineate layers thinner than the tuning thickness. The SA algorithm generates both absolute and relative impedances, which provide both qualitative and quantitative characterization of thin-bed reservoirs

Technical efficiency of watermelon (Citrullus lanatus) production in Ogun State, Nigeria

This study was designed to measure the level of technical efficiency, its determinants in watermelon (Citrullus lanatus) production and the constraints in the production system in Yewa North Local Government of Ogun State using a stochastic frontier production function. A combination of purposive and random sampling technique was used to select 80 watermelon farmers for the study. The socio-­‐economic characteristics show that the farmers are predominantly males, mostly (78.8%) married with majority (87.6%) having at least primary school education. The cost and return analysis shows a high net farm income per hectare of ₦25, 574.24. The estimated farm level mean technical efficiency was found to be 65 percent. This result indicates that great opportunities exist for the farmers to increase their productivity and income through improvement in technical efficiency. Age and off-­‐farm income were found to be positively and significantly related to the technical efficiency while education was negatively signed, as expected, but significant. Policies aimed at improving farmers’ access to education through aggressive awareness campaigns and mass mobilizations are recommended by the study

Strategies for Mitigating Building Collapse in Nigeria: Roles of Architects and Other Stakeholders in the Building Industry

Collapse of buildings is one of the several failures of building projects and results either in loss of lives, properties and in some cases both. Often times the professionals in the building industry made up of Architects, Engineers, Planners, Quantity Surveyors, Land Surveyors, Estate Surveyors, Town Planners,  Builders and Project Manager trade blames on who should be held responsible for the failure. Many factors can be adduced to the continuous occurrences of building collapse which, include inadequate monitoring of construction sites by government officials as a result of the vast and fast pace of developments in many Nigerian urban centres; as well as the use of substandard materials, improper soil investigations, bad design and supervision, poor quality construction and poor funding by clients. Using the secondary source of data collection, the paper discusses the roles the architect could play both in practice and in architectural education in mitigating building collapse. Findings reveal that mitigation of building collapse can be achieved in Nigeria through collaborative efforts of all stakeholders involved and concludes that architectural education could serve a supportive role. Keywords: Architects, Architectural Education, Building Collapse, Mitigation, Nigeri

Effect of Job Status, Gender, and Employees’ Achievement Motivation Behavior on Work Performance: a Case Study of Selected Local Government Employees in Ekiti State, Nigeria

This study investigated the effect of job status, gender, and employees’ achievement motivation behavior on work performance. Two hundred and seven (207) local government employees’ opinions were sampled using the achievement motivation questionnaire and the perceived work performance questionnaire. Seven hypotheses were developed and tested using 2 x 2 x 3 Analysis of Variance (ANOVA) statistics. Results confirmed that job status [F (2,206) =5.05, p05]. A significant interaction effect of gender and job status; gender and level of achievement motivation behavior; and job status and level of achievement motivation behavior were also found on work performance. However, there was no significant interaction effect that existed between gender, job status, and the level of achievement motivation behavior on work performance [F(2,206)=.217, p>.05]. Findings were discussed in the light of available literature and it is recommended that efforts should be made to discourage discriminative behavior among sexes while also closing gaps in level managers’ hierarchies and categorizations. This is particularly in terms of derivable incentives, benefits, and pay on their jobs to have a significant impact on the work performance of employees

Influence of tanks liner material on water quality and growth of Clarias gariepinus

Three tank liner materials: polyvinylchloride (PVC), polyethylene and polyester were evaluated in a 93 days experiment for their influence on culture water quality and growth performance of Clarias gariepinus. Fish of average weight of 5.03±0.21g were stocked at 375 per m3 in tanks lined with the aforementioned materials. Fish were hand fed twice a day. Growth performance and water quality parameters were measured using standard methods. Average temperature of 25.09±1.14OC was recorded in the tanks. Dissolved oxygen with the highest mean value of 5.41±0.96 mg/l was recorded in polyethylene lined tanks while the highest mean alkalinity value of 110.38±2043mg/l was obtained in polyester lined tank .Fish cultured in PVC lined tanks recorded the highest mean daily growth rate of 4.87±3.87g while polyester lined tanks recorded the lowest mean value of daily growth rate of 2.95±2.08g. Highest mean food conversion ratio was recorded in PVC lined tanks with the value of 1.59±0.70. Highest mean weight of 22.59±1.56g was obtained in PVC lined tanks while the least mean weight of 15.41±1,11g was obtained in polyethylene lined tanks. Fish cultured in PVC lined tanks had better growth performance when compared to other tanks liner materials. It would be beneficial with respect to fish growth and culture water quality, to use polyvinylchloride materials in lining fish culture ponds and rearing tanks.Keywords: Aquaculture, Liners, Fish Farming, Tank, Clarias gariepinu

Energy-Efficient Construction in Nigeria: The Adoption of Expanded Polystyrene Wall Panels in Abuja Metropolis

In recent times, Abuja, the Federal capital city of Nigeria has witnessed an extensive use of innovative building materials including Expanded Polystyrene (EPS) in housing delivery. This is in the quest to develop alternative local building materials to the conventional sandcrete blocks, which is of increasing high cost and import dependent. This paper therefore, reports a comparative study on the use of EPS materials over the sandcrete blocks in masonry works in FCT, Abuja. Data for the research were obtained through interview schedules and observations from five (5) selected case studies of housing projects built with EPS panels in Abuja and compared with other housing projects constructed with sandcrete blocks with the aim ascertaining the comparative advantages of EPS panels over the conventional walling materials. Over one hundred and twenty (120) building professionals (Architects, Engineers, Builders and Quantity Surveyors) involved in the construction of these projects were interviewed. Analyses of the findings indicate that EPS buildings demonstrate high thermal insulation capacity, light weight, faster time, higher strength, greater structural stability and cost effectiveness. The paper concludes that EPS panels are better alternatives to the conventional sandcrete blocks and should be used in place of the former in housing delivery in Nigeria. Keywords: Abuja, building materials, expanded polystyrene, urban housin

Physio-Chemical and Functional Properties of Nine Proso Millet Cultivars

Evaluation of the postharvest properties of nine proso millet cultivars was carried out to determine their physical and engineering properties, which are very useful for designing appropriate systems for process operations such as sorting, drying, heating, cooling, and milling. Nine cultivars of proso millet comprising waxy and non-waxy types, namely Cope, Earlybird, Huntsman, Minco, Plateau, Sunrise, Rise, Dawn, and Panhandle, were obtained from the Panhandle Research and Extension Center, University of Nebraska, Scottsbluff. Results showed significant (p \u3c 0.05) differences in their physical properties, such as sphericity, volume, bulk density, porosity, and angle of repose, which ranged from 0.86 to 0.91, from 3.94 to 5.14 mm3, from 765.49 to 809.67 kg m-3, from 42.49% to 44.20%, and from 22.98° to 25.74°, respectively. The cultivars were also evaluated for their pasting and gelatinization properties, and high correlation was found between amylose content and onset temperature (r = -0.94), peak gelatinization temperature (r = -0.92), peak viscosity (r = 0.84), final viscosity (r = 0.91), and setback viscosity (r = 0.90). The understanding of these basic physical and functional properties of proso millet cultivars will form the foundation for processing them into value-added products

Assessment of Selected Dams in Kwara State, Nigeria

In Nigeria, more than 50% of the geographical area lies in the Savannah. Over time, this area has been vulnerable to the vagaries of periodic and severe droughts, affecting the survival of man and animals. Safe and economic design and construction of dams to store surplus river waters thus assumed greater urgency. However, dam failures and flood issues has caused catastrophic damages and losses of lives and properties. The uncertainties associated with deteriorating dams have necessitated proper and timely assessment and rehabilitation of these structures. This study identifies and investigates relapse in four (4) selected dams in Kwara State namely: Unilorin-, Malete-, Okuta- Oja- and Asa-dam. A series of field inspection was carried out and results obtained were analyzed. Amongst the four dams, Okuta-Oja dam displayed the worst case of relapse with seepages through the foundation and body of the dam. About 20 baffle blocks out of 30 have been damaged in Unilorin dam, while Malete dam was undergoing re-construction owing to seepage failure. Asa dam however remains intact with no physical and structural defect. Unless appropriately handled, ageing and relapsing infrastructural systems can pose a significant problem, threatening economic prosperity and public safety. Thus, monitoring the state of dam structures to ensure timely maintenance is critically important to preventing catastrophic disasters