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The aim of this study is to investigate the effect of process variables during dilute acid pre-treatment and enzymatic saccharification of sorghum stalk for cellulosic ethanol production. The sorghum stalk was pre-treated at different reaction temperature (160 – 220 ), dilute acid concentration (1 – 3 %v/v), solid/liquid ratio (0.06 – 0.15 g/ml) and time (5 – 15 mins). This was followed by fermentation to production and characterization of ethanol. Optimum conditions for pretreatment were reaction temperature of 210 , acid concentration of 3 % v/v, solid/liquid
ratio of 0.1 g/ml and a reaction time of 10 mins. Maximum percentage reducing sugar at this condition was 14 %. The result of ethanol characterization revealed that the ethanol production meets the ASTM standard. Hence, we conclude and recommend that sorghum stalk is a potential feedstock for the production of bioethanol.

This study focuses on the effect cooling rate of different moulds on the microstructure (graphite flakes size, distribution) and mechanical properties of grey cast iron. Two common mould materials namely commercial silica sand and an industrial solid waste of Ferro chrome (FeCr) slag were used. The moulds were produced using Sodium silicate-CO2 process. Three kinds of moulds of Fe-Cr slag, silica sand and combination of these two were made. After ensuring optimum mould properties grey cast iron castings were performed on these moulds.
The Cast iron was melted in and similar item of same geometry were cast successfully using these three different moulds. The results obtained reveal that Fe-Cr slag mould reveals faster cooling rates followed by mixed mould and finally sand mould. Faster heat transfer in slag moulds facilitated to obtain castings with fine microstructure, shorter and uniformly distributed graphite flakes. The microstructure result reveal ggraphite string lengths to be
26.18, 63.12 and 38.62 μm for castings made from the slag, silica sand and combination of these two moulding materials respectively. The effect of microstructure changes on the as-cast mechanical properties such as the hardness, tensile strength and creep properties were observed in each mould as-cast. Interestingly improved ductility and impact toughness has been observed in slag mould castings than either sand or mixed moulds. This improvement of ductility and impact toughness was observed to be 52% and 33% respectively. Fractography
analysis of sand castings shows a rough and cleavage fracture surface due to the presence of large flaky structure of graphite in the iron matrix. Whereas in Fe-Cr slag mould castings which have a flake size of relatively smaller and uniformly distributed reveal largely mixed mode of fracture.

Petroleum exploration have been ongoing in the northern Benue Trough Nigeria, with little success in locating commercial oil pool. Clastic petroleum reservoir has been the main exploration target in the region, despite existence of other possible petroleum reservoir rock types. In this study, field, petrographic and geochemical evidences were presented to show the occurrences of oil in basement reservoir rocks (Precambrian Older Granite), clastic reservoir rocks (Cretaceous Bima Formation) and carbonate reservoir rock (Cretaceous Yolde
Formation) of the region. The studied oils which occurs as brittle solids and viscous fluids in the fractures and/or pore spaces of the studied rocks are believed to have been emplaced into fractures and pore spaces of the studied rocks as conventional light oils that have now been degraded to bitumen by biodegradation and water washing processes. TIC fragmentogram of the saturate fractions of the studied oils show the presence of unresolved complex mixture (UCM) humps, consistent with biodegraded oils. The sterane maturity parameters for the studied oils and their corresponding trisnorhopane thermal indicators (Ts:Tm ratio) are consistent with the thermal maturity values of petroleum source rocks within the oil window. Ternary plot of the relative amounts of C27, C28, and C29 regular steranes in the studied oils show marked resemblance for oils occurring in the Precambrian granitic rocks and the Bima Formation, suggesting the two oils originated from the same petroleum source rock. Oils occurring in the studied Yolde Formation is observed to have originated from a different
petroleum source rock, implying the existence of multiple petroleum source rocks in the Northern Benue Trough.

The phenomenon of retrograde condensation occurs when the reservoir pressure declines below the dew-point pressure causing gas condensation and developing two-phase flow. Material Balance Equation (MBE) of gas condensate reservoirs is a challenge because of the change in fluid composition and complexity of phase behavior. Neglecting the effect of water vaporization may lead to inaccurate predictions of the material balance equation. Therefore, the main objective of this study is to develop an improved MBE model capable of describing
gas condensate reservoirs under significant vaporization of connate water and water influx driving mechanism. A new parameter is developed to consider water vaporization. This parameter is used to derive equations for gas condensate reservoirs considering vaporization effect with and without consideration of water influx. Numerical examples have been developed and used to compare the accuracy of the newly-developed model with conventional ones using actual reservoir depletion and production data. The results indicated that water vaporization has an important effect and should be considered for accurate MBE predictions. Error analysis
showed that the newly-developed equations are more accurate than previously-developed models. The accuracy of the new MBE is attributed to the additional parameter introduced considering high pressure and high temperature conditions. The application of the new material balance equation will have important impact on predictions of initial gas in place, reserve calculation and future simulation studies.

Existing models for performing Nodal Analysis for a production system without displaying charts, has
been identified to be somewhat complex and can only be solved by empirical methods. However, in
this study, a simplified sub-model (Rotimi and Wilfred model) was developed from an existing complex
model (Guo-Ghalambor). In the course of simplifying the complex Guo-Ghalambor model, it was first
solved analytically using differential calculus to obtain a sub-model so that an iteration method such
as Newton Raphson coupled with advanced computer programming used to arrive at a definite
solution. With the use of a computer model, NODARES, nodal analysis was conducted for a range of
data points. The results obtained from the tool revealed that, convergence is fast on the part of using
the Rotimi and Wilfred model to perform nodal analysis. The developed computer model was validated
using a range of data points in the determination of the operating pressure and flow rate at which the
crude oil will be produced. Also, a comparative analysis between Excel Solver and the developed
computer model proved that NODARES is most suitable to perform nodal analysis without displaying
charts. Moreover, for visual representation, Poettmann Carpenter model was also used to perform
nodal analysis.

Data acquisition in 3D seismic is influenced by various elements. They may range from lithological features, terrain or environmental conditions to acquisition design parameters, instrumentation, and data collection style. This paper considers the design parameters used for orthogonal geometry seismic acquisition and how they influence the quality of data obtained from surveys carried out using the 3D technique in the Niger Delta region of Nigeria. This study presents an investigation done on six 3D seismic acquisition design data used for land seismic explorations in the Niger Delta. The design parameters investigated were divided into three main categories.
These categories were then independently compared with the nominal fold obtained in each acquisition data studied. The categories are source parameters (parameters related to the source or shot events), the receiver parameters (parameters related to the receivers), and the offset parameters i.e. maximum offset, minimum offset, and largest minimum offset. Regression analyses were carried out to adequately compare the nominal fold and the investigated parameters. Furthermore, mathematical expressions showing the relationships between these parameters and the nominal fold were obtained from the generated regressions. The source point interval, receiver
point interval and the minimum offset were observed to show no direct relationship with the nominal fold. The source line interval, the receiver line interval and the number of receiver lines showed a linear relationship with the nominal fold. Furthermore, a polynomial trend line was observed to exist between the number of source lines, the total source line length, total receivers, the receiver line length, the maximum offset and the largest minimum offset (LMO).