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Abstract
Including sustainability criteria for making decisions in project management poses challenges in the areas of bioenergy, biotherapeutics, and biomaterials. This is mainly due to chemical heterogeneity of bio-based materials, technoeconomic feasibility, and triple constraint of time, cost, and product quality. However, bio-based technologies create opportunities as sustainable processes because they involve upvaluation of locally available renewable and biodegradable materials. This work was conducted to identify challenges and opportunities in incorporating project management tools in bioproduct development with the goal of integrating measurable sustainability criteria scores in decision-making. The scores or metrics from these tools can be used by project managers for decision-making in engineering process scale-up, evaluation of social impact, and commercialization of processing technologies.
Abstract
It is important to assess firms’ financial health in the harsh construction market of developing countries. This study seeks to achieve this by assessing locally owned construction firms’ (LOCOFs) financial performance through evaluating firms’ bill of quantities (BOQ) contract sums and bid unit rates of common building items. Accessible 60 BOQ of the 79 BOQ of building projects awarded to various LOCOFs from 2007 to 2015 by federal universities and federal universities teaching hospitals in Southwest Nigeria were obtained from the institutional archives. Regression analysis of the contract sums and bid unit rates of common building construction items of works such as concrete, sandcrete block, iron, mortar and floor tiles were carried out. LOCOFs’ bid unit rates were compared with published unit rates and Nigeria consumer price index (CPI) within the study period and inferences bothering on firms’ pricing pattern and financial viability of firms based on items of work unit rates were highlighted and discussed. The results showed that 119 out of a total 461 unit rates values representing 25.81% of the LOCOFs bided unit rates were higher than the published unit rates. LOCOFs unit rates trend decreased within 3 to 4 consecutive years while the Nigeria CPI trend increased all through the years considered in the study. This implies that LOCOFs common items of work bids unit rates were not always influenced by the prevailing prices of goods and services in Nigeria. A possible reason for this is the lowest tender selection criteria which influences LOCOFs’ bided unit rates thereby leading to the acclaimed compromise in the quality of construction output and stunted financial performance.
Abstract
The construction industry influences and accelerates national growth and development, but it, however, contributes to unsustainable and eco-unfriendly development which impacts on the economy and environment. To encourage investment in sustainable construction, this study made a case for green building materials (GBM) products and services market in the construction industry of developing countries, through an assessment of the benefits of GBM incorporation in construction projects. The study adopted an internet-mediated questionnaire survey approach and snowball sampling techniques to gathered data from clients, consultants, professionals, and contractors/sub-contractor in the southeast geopolitical zones of Nigeria. Frequency, Percentile, Shapiro-Wilk test, Kaiser–Meyer–Olkin (KMO) and Bartlett’s tests, relative importance index (RII) and Kruskal-Wallis test were used to analyse the collected data. The study revealed that the green construction market is unsaturated and under-tapped. With high awareness and low adoption levels of GBM, it was concluded that the most important benefits of GBM that will trigger demand and supply of GBM products and services are improved daylight and reduced need for artificial lighting, improves the quality of life, Increase employees productivity and reduced absenteeism, improve occupants health and comfort, higher profit and return on investment, leads to construction professionals specialisation, reducing greenhouse gas emission from building, reduces toxicity in the internal environment, low operating and maintenance cost, and creates new job opportunities. The uniqueness of this study lies in the assessment of the views of construction stakeholders' in the five states that make up the South-eastern geo-political zone of Nigeria, regarding the key benefits that could trigger the uptake and incorporation of GBM in construction. Developers and Investors in the industry could invest in green construction since there is a ready and unsaturated market for it.
Abstract
A key factor for motivating intending buyers of raw materials is vendor responsiveness. Therefore, to meet demand, a pre-approved level of stocks is often maintained. In contrast, the decision to keep an uncontrolled amount of stock could be counter-productive with cost components associated with holding often ignored unintentionally. In this study, the objective is to develop a spare parts inventory model that incorporates ignored holding costs with a storage constraint for a motorcycle assembly plant (MAP). The inventory policy, structure of holding costs, and spare parts sales reports were consulted for relevant data. The spare parts were categorized and selected using ABC analysis. A spare parts inventory model, which considers ignored holding cost, was formulated. The model was executed using Lingo optimisation software release 18.0.56 to determine the pair of the order quantity (Ɋ) and reorder point (Ɍ). 177 spare part items were identified using ABC analysis. The parts categorisation revealed that 21, 31, 125 part items belong to categories A, B, and C with 81, 15 and 4% of annual sales value, respectively. From category A, nine items contributed significantly to overall sales. The demand pattern for these items was probabilistic based on their coefficient of variation. The pair (Ɋ, Ɍ) for items N, Z, AY, K, AM, J, P, AL and AZ are (174,688), (71,147), (78,150), (86,163), (18,15), (88,170), (128,118), (33,43) and (87,152), respectively. These pairs yielded a total inventory cost of ₦2,177,363 when compared to the current total inventory investment of ₦6,800,000 resulting in a 67.9% cost reduction. A model to manage spare parts inventory with relevant holding cost components was developed for MAP to ensure the availability of items, maximize usage of storage space, and minimize total inventory cost.
Abstract
Effective stakeholder management (ESM) is a critical success factor for projects. The increasing complexity in the relationships among stakeholders and their diverse characteristics, including power and interests makes the management of stakeholders increasingly challenging. To date, much of the literature has focused on the stakeholder analysis with very limited to the direct and indirect relationships between stakeholder characteristics (SC) and project performance (PP). Therefore, the aim of this study is to fill these research gaps by empirically examining (1) the relationship(s) between SC and PP and (2) the mediation effect of ESM on the above-mentioned relationships. Data analysis was conducted using structural equation modelling. The findings suggest that stakeholder legitimate behaviour (LB), opposing behaviour (OB), and conflicting interests affect the ability to achieve both sets of quantitative and qualitative PP negatively. ESM has been identified as a key element to eliminate the negative effects of the aforementioned behaviours on qualitative (and not quantitative) PP measures.
Abstract
The purpose of this paper is to present an optimization model for planning the distribution of materials in earthmoving operations, considering possible interferences between cut-and-fill sections such as rivers, vegetation, topographical features, or expropriations. The earth allocation problem incorporating interferences was modeled as a linear programming problem, aiming to minimize the total earthmoving cost while considering the constraints related to volume balance, construction project duration, and time for the release of traffic. The proposed linear programming model was run by an integrated system, using Excel for data analysis and IBM CPLEX as the optimizer. The mathematical model was evaluated by a sensitivity analysis and validated by a real-world project of a dam access road in the state of Ceará, Brazil. The unit costs and productivity rates used in the fictional example and in the real-world application followed the referential cost system created by Ceará’s Secretariat of Infrastructure (SEINFRA-CE). The proposed optimization model achieved reasonable processing times for all tested applications, presenting itself as a viable and efficient option for planning earthmoving operations. Furthermore, the linear programming approach provided a 2.12% cost reduction for the real-world case study, when comparing the optimized solution and original budget. This study explored the problem of earth allocation with interferences using a linear programming approach, while avoiding complex modeling issues found in recent literature. As a result, this paper proposes a user-friendly optimization system that can be easily utilized by construction companies and departments.
Abstract
Flood events around the world result in the loss of human lives, disruption, damage to economic, infrastructural and ecological systems. Although, different frameworks to manage flood events exist; however, the complexity (i.e. adjustment and adaptation) associated with some of these approaches is often limited by constraints of time and resources. Therefore, this study attempts to apply a flexible project structure to schedule a post-flood recovery project (PFRP). Twenty-five (25) restorative activities in a PFRP were identified, categorised and scheduled as resource-constrained project scheduling problem with a flexible structure (RCPSP-FS). Monte Carlo simulation was used to reflect the uncertain characteristics of each restorative activity. PFRP completion time was 42 and 86 days under time and resource constraints assumptions, respectively. Thirty- four (34) network paths (sub-projects) were identified and grouped into 4 restorative measures as follows: (i) removal of hazardous materials (ii) evacuation of injured persons (iii) provision of flood technology warning system and technical facilities and (iv) construction of shelter, homes and bridges. Time and cost flexibility values for the network paths range from 6 to 63 days, and 14.79 to 288.77 thousand USD, respectively. Time and schedule sensitivity analysis revealed the impact of each restorative activity on simulated project completion time. Based on these results, it is concluded that a flexible project structure can respond to changing circumstances during post-flood restoration efforts which allow more degree of freedom in activity scheduling, flood events measures and cost alternatives.
Abstract
The waste generation from old rubber tires has been increasing and causing environmental degradation with the escalation of vehicles number especially in the cities. Bitumen is extensively used in flexible pavement construction and as its manufacturing industries were still growing, the cost has not been much affordable. This study aimed at evaluating the possibility of a partial replacement of ordinary bitumen by tire rubber waste, with the purpose to reduce not only the amount of rubber wastes dispersed in the nature, but also the material cost, while keeping or improving the bitumen product performance. The study used rubber waste powder as partial replacement to ordinary bitumen by 5%, 10%, 15%, and 20% of its weight and, with adequate samples, properties of the bitumen product were investigated, after checking the standard quality of used bitumen 60/70 grade. It was established that more adequate results were achieved at 5% of replacement, which showed the penetration value of 61.66 tenths mm, the softening point value of 52.750C, and the viscosity of 134 sec. Regarding the cost estimation of this new bitumen, a cost reduction of around 5.3% was realized. Therefore, the use of rubber waste powder would contribute not only to the reduction of the quantity of respective waste in the environment, but also influence on the material affordability. The use of other grades of bitumen than 60/70, as well as the strength and durability performance may be a good scope for further studies.
Abstract
The objective of the present study was to develop a robust, simple, economical and sensitive HPLC-UV method using the “quality-by-design” approach for the estimation of irinotecan (IRI) in marketed formulations. RP-HPLC method was developed by applying Box-Behnken design with Hyper-Clone (Phenomenex®) C18 column (250 × 4.6 mm id, particle size 5 µm, ODS 130 Å) as a stationary phase. Acetonitrile and 20 mmol L−1 potassium phosphate buffer (pH 2.5) containing 0.1 % triethylamine in a ratio of 45:55 % (V/V) was used as a mobile phase. The sample was injected in a volume of 20 µL into the HPLC system. UV detector at 254 nm was used to estimate and quantify IRI. Isocratic elution was opted while the flow rate was maintained at 0.75 mL min−1. The retention time of IRI was found to be 4.09 min. The responses were found to be linear for concentration range of 0.5 to 18.0 µg mL−1 and the coefficient of determination value was found to be 0.9993. Percent relative standard deviation for intra- and inter-day precisions was found in the range of 0.1 to 0.4 %. LOD and LOQ values were found to be 4.87 and 14.75 ng mL−1, resp. Robustness studies confirmed that the developed method is robust with RSD of a maximum 0.1 %. The method is simple, precise, sensitive, robust and economical making it applicable to the estimation of IRI in an injectable formulation.