Cr-doped La-Ni-O catalysts derived from\ua0perovskite precursors for CH4-CO2 reforming under microwave irradiation

The nickel catalysts derived from Cr-doped LaNiO perovskite-like precursors were characterized by X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed oxidation, temperature-programmed reduction, and X-ray photoelectron spectroscopy. Their catalytic performance in CO reforming of methane under microwave irradiation was investigated. It was found that the structure and morphology of the oxide composites in this research were influenced by the ratio of Ni and Cr, and the mismatch of La, Ni, and Cr may cause phase segregation. The catalytic performance of the Ni catalysts is dependent on the oxygen mobility of the perovskite oxide matrix, the content of the reduced Ni, and the content of the remaining perovskite structure. The mobile oxygen in the perovskite matrix in the catalyst may enhance the conversion of CO during the reaction

Determination of Optimal Crew Size in Project Segmentation to Minimize Cost

Stakeholders and contracting board have begun to utilize innovative contracting methods that provide new incentives for reducing construction duration. These methods have placed increasing pressure on decision makers in the construction industry to search for an optimal construction plan that minimizes construction time and cost while preserving quality. This paper considers the problem of finding the optimal number of segment(s) that minimizes total project cost of a non-homogenous road construction project located in a city in South West, Nigeria. A mathematical programming model approach was adopted to obtain the optimal number of segments as opposed to when the activities of the project are scheduled sequentially. Also, Binary interaction matrix (BIM) was used to define stated relationships between fixed and variable quantities of the cost and duration respectively. Given stipulated due date of 8 months with a penalty / bonus of N 63091791/month. The analysis shows that the optimal number of segments into which the project can be divided into is three and that by working in parallel the project will be completed in 5 months at a cost of N1,409,609,413. This is opposed to the original contract lump sum of  N 1, 577, 294, 775 with a normal duration of 12 months. A saving of 1.55% was realized. This work demonstrated the possibility of dividing a continuous repetitive project into a numbers of segments of equal work content, working in parallel, using optimum crew size such that the duration and the total cost of the project can be minimized. Key words: Project Management, Scheduling, Construction planning, Natural Rhythm, Project Segmentatio

Developing Flood Resilient Buildings in Nigeria: A Guide

Acknowledgements We acknowledge the support of the UI Ibadan TETFUND IBR 2016 Research Project Fund. Abstract Recently, the damage caused by flood in Nigeria has become unbearable leading to series of economic losses. Several post flood measures taken has proved to be inadequate because they are temporary. Hence, the needful is the flood risk management. Managing the risk of flood can be achieved by enhancing the resilient of the buildings in Nigeria. This requires a pragmatic approach from the concerned stakeholders. In this paper, we observed and discussed some of the drawbacks in Nigeria buildings leading to its vulnerability to flood. Also, guide was developed for government and stakeholders to achieve the incorporation of resilience in Nigeria building and its environment. Expected resilience was proposed and a flowchart to assist the prospective builders was developed. This will assist in developing the necessary blueprint towards achieving this goal. Necessary suggestions made will aid in the actualization of a resilient buildings within Nigeria. Keywords: Flood, resilience, Nigeria, flood risk management, buildin

A SYSTEM DYNAMICS MODEL TO DETERMINE THE VALUE OF INVENTORY HOLDING COST

Traditionally, Inventory Holding Cost (IHC) is assumed to be a combination of several costs and determined by the summation of these cost components. Several authors have suggested that the value of IHC ranges between 12-50% of the procurement cost of an item. However, due to the absence of a generally acceptable methodology, many practitioners still determine this percentage based on estimates, benchmarks and intuition. Giving considerations to this reality, a mathematical model to determine the value of IHC using systems dynamics approach was developed. IHC was viewed holistically to identify relevant quantities, their interactions (static or dynamics), behaviour and consequences. A Causal Loop Diagram (CLD) was developed to establish the relationship among these quantities. Thereafter, CLD was transformed into a Flow Diagram (FD). FD was used to formulate a set of systems dynamics equations to obtain IHC. The interaction among fraction of goods ordered per month (FOM), fraction sold per month (FSM) and fraction damaged per month (FDM) was simulated to obtain percentage values of IHC. The value of IHC obtained from the model and simulation analysis ranges between 22.58-25.39% of the item held in stock. Based on these results, it is concluded that the developed model can be used for simulation and system analysis of the holding cost component of an inventory system under different contextual settings

A SYSTEM DYNAMICS MODEL TO DETERMINE THE VALUE OF INVENTORY HOLDING COST

Traditionally, Inventory Holding Cost (IHC) is assumed to be a combination of several costs and determined by the summation of these cost components. Several authors have suggested that the value of IHC ranges between 12-50% of the procurement cost of an item. However, due to the absence of a generally acceptable methodology, many practitioners still determine this percentage based on estimates, benchmarks and intuition. Giving considerations to this reality, a mathematical model to determine the value of IHC using systems dynamics approach was developed. IHC was viewed holistically to identify relevant quantities, their interactions (static or dynamics), behaviour and consequences. A Causal Loop Diagram (CLD) was developed to establish the relationship among these quantities. Thereafter, CLD was transformed into a Flow Diagram (FD). FD was used to formulate a set of systems dynamics equations to obtain IHC. The interaction among fraction of goods ordered per month (FOM), fraction sold per month (FSM) and fraction damaged per month (FDM) was simulated to obtain percentage values of IHC. The value of IHC obtained from the model and simulation analysis ranges between 22.58-25.39% of the item held in stock. Based on these results, it is concluded that the developed model can be used for simulation and system analysis of the holding cost component of an inventory system under different contextual settings

MANAGING SUPPLY CHAIN RISKS: A FUZZY-FAILURE MODE AND EVALUATION APPROACH FOR RANKING THREATS

On the backdrop of lower transportation cost, outsourcing paved the way for borderless production activities and ushered in the era of Supply Chain Management (SCM). For many organizations, achieving the goals of their Supply Chain (SC) is constantly threatened by increased competition and disruption. In this study, the aim is to identify, and rank, SC threats in a developing country using Failure Mode and Effects Analysis (FMEA) with Fuzzy Logic (FL). FMEA parameters were derived for 44 supply chain threats (SCT1 – SCT44) and their Risk Priority Number (RPN) determined. Subsequently, the Mamdani Fuzzy Inference system was utilized to arrive at a Fuzzy-RPN with 125 rules using severity as a determining factor. The rules were ranked to prioritize SC threats. From the conventional FMEA, demand variation (SCT42) and long-distance sourcing (SCT27) had the highest and lowest RPN, respectively. After fuzzification and defuzzification, Fuzzy-RPN identified raw material delay (SCT1), government policy (SCT11), poor transport infrastructure (SCT18) and political instability (SCT19) as threats with the highest Fuzzy-RPN (210) and product recalls (SCT28) with the lowest Fuzzy-RPN (99). Based on these results, it is concluded that a Fuzzy-FMEA approach can identify and rank SC threats with the use of an RPN devoid of sentiments and inaccuracies