Ethno-religious mobilisation and the sapping of democracy in Nigeria: on the legacy of the transition programme

Paper presented at the Wits History Workshop: Democracy, Popular Precedents, Practice and Culture, 13-15 July, 1994

Implementation of the value re-engineering concept in the Nigerian construction industry: Exploratory study

Value Re-Engineering (VRE) is considered a critical analysis and radical redesign of existing construction processes to achieve breakthrough improvements in performance measures. The dissatisfaction of customers’ value offered by the Nigerian Construction Industry (NCI) necessitated a rethink of a new approach to the customers’ need. Hence, this article aims to explore the implementation of VRE in the NCI as a possible solution for the industry to resolve the challenges of customers’ dissatisfaction. A qualitative research approach was used to identify incremental adoption for the implementation of VRE in the NCI. Qualitative data was collected, using a structured tick-box questionnaire interview schedule with 34 key stakeholders in the NCI, including seven directors, nine project managers, nine quantity surveyors, and nine engineers. The tick-box interview schedule explored the level of importance of the activities of the implementation process in the eight phases (steps) for VRE take-off in the NCI. Using QSR Nvivo 12 (a qualitative content analysis tool), the tick-box data was given a numerical score, on a 5-point Likert scale, so that the data could be rated and reported quantitatively. This included frequencies and percentages. The exploratory research findings indicate that there is a significant need for the process to be re-engineered and for establishing a VRE organisational structure critical to achieving the successful implementation and adoption of VRE. Other most important activities for the successful implementation of VRE include evaluating the impact of new technologies; monitoring employee attitudes, customer perceptions, and supplier responsiveness, as well as identifying disconnects (anything that prevents the process from achieving the desired results and, in particular, information transfer between organisations or people). Identifying the customers’ needs by the NCI helps create the market value of the product being produced by the industry players. On the other hand, this improves the global competitive market for the industry by adopting the radical redesign process for the industry

Analysis of temperature and pressure surge distribution for single phase gas flow during wellbore shut-in and start-up

Analysis of temperature and pressure surge distribution for single phase gas flow during wellbore start-up and shut-in is a complex phenomenon for gas producing industries. Its occurrence forced the flowing gas to stop abruptly creating a pressure surge and high temperature within the wellbore system. This situation has to be studied for proper characterization, and protection of the producing wells from damage and premature closure. Many authors studies this phenomena in order to have a permanent solution but yet the problem still remain due to differences in environment. In this work, a one-dimensional transient governing equation based on depth and time dependent for start-up and shut-in has been developed. It is solved by finite difference scheme of Steger Warming Flux Vector Splitting Method (FSM). The method is fully transient and unconditionally stable. Surge pressure were analysed and wellbore temperature is predicted using the unsteady state heat transfer model. The results shows that if shut-in time is short, the sound wave propagation speed is faster than that of its longer time period. The result of this work provides a technical reliance to gas producing industries and can serve as guidance in field operations to avoid gas leakages or wellbore damage

A novel hybrid ARFURIMA-APARCH model for modeling interminable long memory and asymmetric effect in time series

In this paper, we introduce a new hybrid model namely Autoregressive Fractional Unit Root Integrated Moving Average-Asymmetric Power Autoregressive Conditional Heteroscedasticity (ARFURIMA-APARCH) model. The Nigeria daily COVID19 records and Bitcoin to EURO exchange rate that exhibit a type of Long Memory (LM) called Interminable LM (ILM), volatility and asymmetric (leverage) effect were used to show the applications of the proposed ARFURIMA-APARCH model. The existing Autoregressive Fractional Integrated Moving Average-Asymmetric Power Autoregressive Conditional Heteroscedasticity (ARFIMA-APARCH) model were estimated and compared with the ARFURIMA-APARCH model. Results showed that the new hybrid model is better based on goodness-of-fit, serial correlation tests and forecast measures of accuracy. As a conclusion, our study showed that the ARFURIMA-APARCH model performed better compared to the ARFIMA-APARCH hybrid model. Therefore, the ARFURIMA-APARCH model is a better option for modeling ILM, volatility and leverage effect of health and financial data. Future study should focus on the application of the developed hybrid ARFURIMA-APARCH model using some major economic indicators, for example, Gross Domestic Product (GDP), currency exchange rate, stock price index, interest rate and other financial data

Modeling and simulation of transient flow characteristics in a producing gas well

Modeling transient flow characteristics in a producing gas well has been a problem long over in natural gas industry due to parameter changing during operation. In the past, authors concentrate on application of correlations and steady state approach, but most of their works does not give satisfactory results because the used applications neglect the transient aspect leading to premature closure of most wells. Many existing models are proposed to correct these anomalies using simplified governing equation ignoring the transient aspect of the flow characteristics. A one-dimensional transient compressible model comparing the conservation of mass, momentum and energy has been presented to investigate the transient behavior of flow characteristics in a producing gas well staged at different inclination due to environment change. The model is solved numerically using the implicit Steger-Warming flux vector splitting method (FSM). The work investigates flow characteristics along depth of the well using different wellbore diameter of 0.073m, 0.0883m, at different time and different thermal conductivities. It shows that transient occurs due to the temperature difference between the produced gas and the flow environment while gas pressure increases due to difference between wellbore pressure and reservoir pressure. The result of this work reflect gas flow law and the characteristics of heat transfer in formation

Probabilistic Durability Analysis of Reinforced Concrete Members with Corroded Reinforcing Steel

The reliability of the structural performance of any given structure is affected by both in-service loading and material deterioration due to environmental attack. In this paper, probabilistic assessment of reinforced concrete members exposed to chlorine ingress was undertaken. A simply supported reinforced concrete slab was specifically used for the investigation. The mathematical models of capacity loss of reinforcing steel under corrosion, developed elsewhere, were incorporated in the analysis. The uncertainties in structural resistance and the applied loading were fully accommodated using probabilistic method. Limit state function for the flexural capacity of the slab was developed and evaluated using first order reliability method (FORM). The entire process was implemented through a developed program using MATLAB

Bridge Collapse in Nigeria: A Case Study of Tatabu Bridge in Mokwa Local Government Area of Niger State

Large parts of Niger State are located in low terrain and have proximity to River Niger: the largest river in Nigeria; coupled with the presence of three hydro Electric power stations in the state. Niger State has been confronted annually by flood disaster that has destroyed many lives and properties. The focus of this paper is to investigate the causes behind Tatabu bridge collapse. In this investigation, soil strength and index test, hydrological data, nature of the terrain, concrete strength test and evaluation of flood impact on the bridge and its embankments using ANSYS Finite Element Method were conducted. The results of the investigations revealed that the collapsed bridge was positioned within a valley as well as steady increase in precipitation from 2015 to 2017 which directly increased the stream flow rate and also runoff.  It was also observed that the debris settlement within the cell of the collapsed bridge contributed to reduction of the cross sectional area of single cell. The compressive strength test of the bridge members revealed that the strength are within acceptable limit. The authors recommended that there is the need for embankment protection either covers vegetation, stone pitch, slope stabilizer, or concrete interlocking is required for future consideration. Due to increase in water balance, the new bridge capacity should be increased to accommodate the high volume of water.  The new bridge should be reconstructed above the valley or repositioned away from the valley. it is also recommended that a complete replacement of the underlain material forming the adjacent slope to the bridge retain wall with a better compacted engineering soil to avoid future pavement failure of the kind. Keywords: Bridge, Flood, ANSYS, Collapse, Terrai

Investigation of the inhibition efficiency of Irish potatoes leaves extract on aluminium sheet in acidic medium

Aluminium is the most widely used non-ferrous metal, hence there is need to protect it from corrosion. This research work, investigated the inhibitive property of the ethanol extract obtained from Irish potato leaves (Solamun tuberosum) for aluminium corrosion using 2M H2SO4 as a medium. The inhibitive effect of the extract against the corrosion of aluminium was investigated using gravimetric technique at various concentrations of the extract (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 g/L). The results revealed that with increase in concentrations of the extract, the corrosion rate decreases and the highest inhibition efficiency was found to be 77.78% at 4.0 g/L of the extract. Additionally, the adsorption of the extract on the aluminium surface was found to obey Langmuir’s adsorption isotherm. However, the plant extract proved to be effective inhibitor on the corrosion of aluminium in the acid medium and can be used as green inhibitor