Interim : Interdisciplinary Journal - Volume 12, Issue 3, 2013
Volume 12, Issue 3, 2013
Author A.O. AiyetanSource: Interim : Interdisciplinary Journal 12, pp 1 –15 (2013)More Less
Construction projects all over the world involve many challenges, particularly for large public projects. The emerging complex nature of construction activities has brought with it characteristic features, such as, cost increases, delay in the delivery of project, to which rework (carrying out an activity more than one time) has a high contributing factor, stemming from imperfection. This study identified the sources of rework on construction projects in Nigeria from three perspectives: the client, contractor, and consultant. The study was concentrated on the South West part of Nigeria. The quantitative research method was adopted. Random sampling technique was employed in the selection of sample size. A total of one hundred and twenty (120) questionnaires were analysed using inferential statistics.
The following are the findings of this study: the contributions of the client leading to rework are in the form of poor communication, inadequate construction planning and poor management practices. From the consultant, they are: lack of understanding and correct interpretation of customer requirements, constraints in carrying out activities and inexperience of personnel and on the part of the contractor they are: wrongly laying of forming course, poor quality concrete, and poor plastering. Based on the conclusions reached, the following recommendations were drawn. They are: the development of a standard information gathering format relative to clients 'by designers and clients' writing down their intentions before visiting designers; formal technical training should be given to foremen on permanent appointments with organisations, attention should be given for adequate supervision, and construction methods should be analysed before selection and their use.
Source: Interim : Interdisciplinary Journal 12, pp 16 –27 (2013)More Less
Hardly could projects be executed in Nigeria without alteration of design. This cannot be dissociated from designs which are not practically buildable or arising from changing taste of client. A study on factors influencing the buildability of designs in Nigerian construction industry was carried out to determine these factors and develop strategy to mitigate them. A total of one hundred (100) questionnaires were administered by the means of convenience and eighty six (86) was retrieved from a target population comprising; Architects, Builders, Engineers and Quantity Surveyors. The central tendency statistical tool was used for the analysis of data. The result of data analysis indicated that, clients briefing is an important factor for buildability of design. Among the influencing factors on buildability, complexity of the project followed by professional knowledge about construction ranks first and second and lastly cost economic value with no influence. On the current practice of buildability in Nigeria, the study revealed that Architects are mainly involved at the briefing stage to the award stages. While at the construction stage the Builder/Constructor features prominently at the various phases of construction. The study recommended the integration of Builder/Constructor at the early stage of building design.
Source: Interim : Interdisciplinary Journal 12, pp 28 –41 (2013)More Less
Fly Ash is a by-product at thermal power stations, also otherwise known as residues of fine particles that rise with flue gases. An industrial by-product may be inferior to the traditional materials used construction applications, but, the lower the cost of these inferior materials make it an attractive alternative if adequate performance can be achieved. The objective of this study is to evaluate the chemical and physical effectiveness of self-cementing fly ashes derived from thermal power stations for construction applications with combined standards. Using laboratory testing specimens, suitable types of Fly Ashes namely: Kendal Dump Ash, Durapozz and Pozzfill, were tested to the required standards to evaluate the potential properties. All three Fly Ashes have been classified as a Class F Fly Ash, which requires a cementing agent for reactions to take place and for early strength gains in the early stages of the reaction processes. The Fly Ashes conformed to the combination of standards and have shown that the proper reactions will take place and will continue over period of time. The use of fly ash is accepted worldwide due to saving in cement, consuming industrial waste and making durable materials, especially due to improvement in the quality fly ash products.
Author D.K. DasSource: Interim : Interdisciplinary Journal 12, pp 42 –59 (2013)More Less
South African cities are in the process of transition in the changing scenario and need a change in the planning perspective for their sustainable development. The concept of smart city offers opportunities for such development to many middle sized cities of South Africa. Therefore, in this paper conceptual modelling for development of smart cities in South Africa is attempted based on systems concept. The conceptual models are built by using the principles of system dynamics methodology and based on causal feedback relationships among the various factors under different smart characteristics of a city such as, smart economy, smart people, smart governance, smart mobility, smart environment and smart living. The causal feedback loops and interrelationship among various parameters illustrate the dynamicity and influence of parameters on one another, which would able to assist in evolving plausible policy interventions for developing smart cities in South Africa. It is concluded that the modelling approaches presented here could guide the policy makers and city planners to evolve robust and responsive policy interventions for developing smart cities in the changing scenario.
Source: Interim : Interdisciplinary Journal 12, pp 60 –72 (2013)More Less
The objective of this study was to characterize meteorological droughts in the Central Region of South Africa, Modder River Basin, C52A quaternary catchment using two popular drought indices: Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI) and to compare the two indices. Drought events were characterized based on their frequency, duration, magnitude and intensity. The indices were computed for the time-scales that are important for planning and management of water resources, i.e. 3-, 6- and 12-month time-scales. The basic meteorological input data used in the computation of these indices were 57 years (1950-2007) of monthly precipitation and monthly temperature data which were recorded at The Cliff weather station in the quaternary catchment. It was found that both SPI and SPEI responded to drought events in similar fashion in all time-scales. During the analysis period, a total of 37, 26 and 17 drought events were identified in the area based on 3-, 6-, and 12-month times-scales, respectively. Considering event magnitude as severity parameter, results from both indices identified the periods 1984-1985, 1992-1993 and 2003-2005 as the severest drought periods in the area. However, when the effects of both drought duration and magnitude are considered (drought intensity), the most severest drought events were identified during the years 1982/83, 1966 and 1973 based on 3-, 6- and 12-month timescales, respectively. It was concluded that although the SPEI generally exhibits veracity over SPI by including, apart from precipitation, additional meteorological parameter, mean temperature, SPI should be adopted as an appropriate drought monitoring tool in an area, like Africa, where meteorological data are scarce.
Evaluation of the SWAT model in simulating catchment hydrology : case study of the Modder River BasinSource: Interim : Interdisciplinary Journal 12, pp 73 –85 (2013)More Less
This paper presents the set-up and the performance of the SWAT model in the Modder River Basin. Two techniques widely used, namely quantitative statistics and graphical techniques, in evaluating hydrological models were used to evaluate the performance of SWAT model. Three quantitative statistics used were, Nash-Sutcliffe efficiency (NSE), present bias (PBIAS), and ratio of the mean square error to the standard deviation of measured data (RSR). The performance of the model was compared with the recommended statistical performance ratings for monthly time step data. The model performed well when compared against monthly model performance ratings during calibration and validation stage.
Runoff and soil loss under different tillage and cropping system practices at Ginchi Vertsol in EthiopiaSource: Interim : Interdisciplinary Journal 12, pp 86 –101 (2013)More Less
To assess and predict runoff and soil loss on different tillage methods coupled with alternative cropping systems in the central highland vertisols of Ethiopia, a study was carried out at Ginchi, Agricultural Research Sub-Center during 1996. The experiment was conducted on runoff plots of 4 meter wide by 22 meter long, on surface slopes that range between 0.1% and 2.3%. The data collected was analyzed using regression models and an empirical formula developed by the Soil Conservation Service of America (SCS, 1964; 1972), known as curve number (CN). Both the regression model and the SCS simulated the mean daily runoff reasonably well with R2 93% and 83%, respectively. The overall results obtained explain that the improved tillage practice, BBF could drain the excess surface water safely.
Source: Interim : Interdisciplinary Journal 12, pp 102 –115 (2013)More Less
In the actual learning situation, students develop context specific strategies for learning in response to their own perceptions of the requirements for learning. Among all the contextual factors, assessment has been demonstrated to have a powerful effect on the learning process and is a defining feature of the students' approach to learning. However, assessment in the engineering discipline is typically orientated towards demonstrating competence in specific tasks using only traditional assessment techniques. However, the effectiveness of education programmes is dependent on how well lecturers understand the role of assessment in student learning and how well they are prepared to change their strategy in such a way that they use assessment as a tool for the improvement of student learning.
Techno-economic analysis of an off-grid micro-hydrokinetic river system for remote rural electrificationSource: Interim : Interdisciplinary Journal 12, pp 116 –129 (2013)More Less
This study investigates the use of off-grid micro-hydrokinetic river system as a cost-effective and sustainable electricity supply option for remote rural residents in close proximity to flowing water and not having access to grid electricity. This hydrokinetic technology is still in the development stage and there is a lack of application especially in rural areas with reasonable water resource. This study will present the economic and environmental benefits of the proposed system. A mathematical model is developed to simulate the system performance as submitted to different solicitations. A test prototype will also be used in order to validate the simulation results.
Source: Interim : Interdisciplinary Journal 12, pp 130 –145 (2013)More Less
This paper gives an overview of the research in developing a protocol to synchronize information in a secure wireless mesh network. The aim of the research is to development a protocol that can be loaded on a microcontroller with limited resources. The protocol will minimise human interference and will automatically negotiate which device becomes the master controller. The device must have the capability to be stationary or mobile and host multiple control points.
Source: Interim : Interdisciplinary Journal 12, pp 146 –158 (2013)More Less
Web technologies are proliferating through plant automation systems and enabling managers to review production and control data from anywhere they can access the Internet . Web-based plant monitoring can be used to obtain production data, such as how much is each plant producing, what widgets are getting produced, what are the supply levels and what orders have been filed. In this paper development of a web based monitoring and control system for an assembly system at Research Group in Evolvable Manufacturing System (RGEMS) is proposed. This development includes the integration of Object Linking and Embedding Process Control (OPC) technology and web technology. This paper also discusses the security issues of a remote accessible system.
The implementation of communication developed with genetic programming techniques within the RoboCup domain (June 2013)Author A.B. Van Der WaltSource: Interim : Interdisciplinary Journal 12, pp 159 –173 (2013)More Less
RoboCup teams developed through Genetic Programming (GP) still fall short of their hand coded counterparts. This study evaluates the addition of communication to determine if developed teams will demonstrate improved performance and whether current GP techniques can evolve communication. Three cases were selected to be presented. The first case's fitness function rewarded communication, whereas case two relied on a simpler fitness function; however both resulted in a lack of communication evolving. Case three forced players to respond to messages, which resulted in more structured team play evolving. This indicates that current GP techniques are insufficient and that alternative approaches needs to be pursued in future research.
Source: Interim : Interdisciplinary Journal 12, pp 174 –187 (2013)More Less
The Software Usability Measurement Inventory (SUMI) testing technique is a rigorously tested and validated method to measure software quality from a user perspective. Using SUMI the usability of a software product or prototype can be evaluated in a consistent and objective manner. The technique is supported by an extensive reference database and embedded in an effective analysis and reporting tool. SUMI has been applied in practice in a great number of projects. This article discusses the practical application of SUMI in a operational environment where second year Information Technology students of the Central University of Technology, Free State utilised SUMI as part of their networking subject, System Software 1 to evaluate three Information and Communication Technology network programs. The results, strengths and weaknesses as well as usability improvements are discussed.
Source: Interim : Interdisciplinary Journal 12, pp 188 –194 (2013)More Less
This paper assesses the possible fuel consumption savings of combined optimization of the flight profile (altitude and velocity) and wing morphing (wing length, taper, and sweep). A standard business jet in an international standard atmosphere is modeled and dynamic programming is used to solve the resulting optimal control problem.
Preliminary findings on an investigation into the three most important process parameters that influence laser sintering of Ti64 and validation of a melt pool simulation modelSource: Interim : Interdisciplinary Journal 12, pp 195 –209 (2013)More Less
Direct Metal Laser Sintering (DMLS) is a layer-by-layer Additive Manufacturing (AM) process that creates physical metal parts from three dimensional Computer Aided Design (CAD) data. For DMLS to be generally accepted by industry as a manufacturing technology, high mechanical integrity of final components needs to be demonstrated. Mechanical properties of manufactured components are directly affected by the quality of each individual laser sintered track of each consecutive layer. In this study, the optimal ratio of laser power and scanning speed on single tracks is determined for Titanium-6Al-4V powder on an EOSINT M270 DMLS machine for layer thicknesses that vary between 0 µm and 60 µm. Three different laser powers, namely 150 W, 170 W and 190 W were considered. Scanning speeds varied between 600 mm/s to 2000 mm/s with 200 mm/s intervals. Visual inspection of all the sintered tracks identified nine possible combinations of laser power, scanning speed and layer thickness that yielded stable uniform tracks. The most stable tracks resulted from high laser power, slow scanning speed and thin powder distribution. The empirical data were compared to a melt pool width prediction program and a good correlation was found. It was furthermore found that increased powder thickness can be used with a reduced scanning speed and increased laser power. This strategy may be used to increase productivity. The lack of penetration data during fusion of the tracks onto the baseplate necessitates the need to further investigate the obtained results in order to further narrow down the preliminary nine combinations.
Source: Interim : Interdisciplinary Journal 12, pp 210 –218 (2013)More Less
The issue investigated in this study is the practical implementation of Rapid Casting for Tooling (RCT) concept using locally available technologies. RCT is a tool making process chain essentially consisting in metal casting in sand moulds obtained by rapid prototyping. The production of a sand casting pattern is the case study used to uncover and discuss the complexity and challenges of RCT.