- Farmers' Adaptation Mechanisms to Climate Change and Variability: The
Case of La’Ilay Maichew Woreda, Central Tigray, Ethiopia
Authors: Taddesse Tesfamariam
Abstract: Climate change and variability is rapidly emerging as one of the most serious global problems affecting many sectors in the world and is considered to be one of the most serious threats to sustainable development. The impact of climate change depends on severity of the natural resource degradation and the technological capacity of the people to cope up the changes in climate. La’ilay Maichew woreda in Tigray regional state, is not an exception in this context. Farmers have been making efforts to cope up the adverse impact of climate change and variability by using different adaptation methods. Adaptation method is largely site-specific and site-specific issues that require site specific knowledge. Thus, this research was initiated to address the knowledge gab: to identify the adaptation methods and factors that affect farmers’ choice of adaption strategies. Quantitative design was primarily employed for the study. The essential data were collected from 130 randomly selected farm households using semi-structured interview schedule. Descriptive statistics and MNL logit model were used for analyzing quantitative data. The study has established that rainfall and temperature in study area have been decreasing and increasing respectively. To adapt this climate change the farmers have been using a combination of adaptive strategies, which include agronomic practices, livestock management and water and soil conservation. The results from MNL highlighted that sex, age, education, family size; farm income, farm size, TLU, extension visit, credit use, and access to climate information were the significant factors that influenced farmers’ choice of adaptation option to climate change in the study area. In general, increasing farmers’ awareness on climate change and variability risk perception, improve farmers’ income-earning opportunities, Moreover, access to extension and credit services are essential to cope up the adverse impact of climate change and variability in La’ilay Maichew Woreda. It was, thus, recommended that policy aimed to reduce adverse impact of climate change in the area could be successful if these factors mentioned above are taken into consideration with respect to the intrinsic nature of climate change adaptation options.
Issue No: Vol. 8
- Asset or Problem: Decision Making and Strategic Ambiguity in Mega Projects
Authors: Malik Ali Naqi
Abstract: In mega projects, the project phases from the initial planning stage to implementation stage can be spread more than twenty year. In this long period numerous external changes occur which will effect on project directly or indirectly. Major factors are political conditions of the country, technology, financial conditions, labor and all working conditions, land and other market conditions will change in long run during the implementation of mega project. A lot of unforeseen events will occurs, these unforeseen conditions, realization and resources causes the different output as compared to expected outputs in the mega projects. That’s why the planning of mega project is most strategic decision making moment in the life of organizations. So, it’s the responsibility of the project managers to keep the mega and complex projects as simple and flexible which can be adjustable in unforeseen condition. In this study the planning of mega projects is explored. The planning of mega projects is most important and organizations must have too kept in consideration the unforeseen conditions in their planning and decision making process. Mega and complex project have different uncertainty and ambiguity factors which can be minimized by taking rational decisions. Keywords: Mega Projects, Project Planning, Rational Decision Making, Strategic Ambiguity and Project Uncertainty.
Issue No: Vol. 8
- Behavior of Reactive Powder Concrete Columns with or without Steel Ties
Authors: Mohammed Mansour Kadhum, Bushra Salman Mankhi
Abstract: In this paper, an experimental work was carried out to investigate the behavior of reactive powder concrete (RPC) columns with or without steel ties. The main objective of this work is to investigate experimentally the behavior of RPC columns, to search the effect of the experimental variables, type of concrete (RPC and NSC), percentage of micro steel fibers and spacing between steel ties. Twelve RPC columns and five NSC columns were cast and tested under concentric axial compression load up to failure and the results are reported herein. The experimental results showed that RPC column specimens failed in a controlled manner without observing spalling of concrete cover or buckling of the longitudinal reinforcement to well beyond the peak load due to the inclusion of steel fibers in RPC. Also, the space and amount of steel ties affect the load carrying capacity of columns by increasing the load carrying capacity with decreasing spacing of lateral ties. Keywords: Reactive powder concrete, Steel ties, Crack width, Load carrying capacity.
Issue No: Vol. 8
- The Bioclimatic Design Strategies, and the Application in the Traditional
Courtyard Buildings in the Climate of Middle East
Authors: Jamal Adwan, Maisa Abu Muhsen
Abstract: During last decades, bioclimatic architecture appears as an essential means for the environmental improvement of the built environment, while the contribution of the bioclimatic approach to outdoor design for the achievement of better living conditions has not been evenly accentuatedTherefore, the aim of this study is to enable architects to re-understand the lessons of tradition, because the way towards bioclimatic architecture should start by understanding vernacular architectureThis research increases the importance of bioclimatic design and application of its strategies on traditional buildings. Recognition the role of traditional courtyard buildings types, materials, techniques and strategies of keeping a healthy surrounding environment, finally realize the important of bioclimatic design and its positive impact on the environment. Keywords: bioclimatic design, traditional buildings, Courtyard buildings.
Issue No: Vol. 8
- Developing Artificial Neural Network and Multiple Linear Regression Models
to Predict the Ultimate Load Carrying Capacity of Reactive Powder Concrete
Authors: Mohammed Mansour Kadhum
Abstract: The study focuses on development a model to predict the ultimate load carrying capacity of Reactive Powder Concrete (RPC) columns. Two different statistical methods regression techniques (RT) and the artificial neural network (ANN) methods were used for determining the RPC columns ultimate load carrying capacity. The data is collected from three experimental studies the first used to develop the model and the other two used as a case study. Experimental results used as input data to develop prediction models. Two different techniques adopted to develop the models the first was Artificial Neural Network (ANN) and the second was multi linear regression techniques (RT). The models use to predict the ultimate load carrying capacity of RPC columns. To predict the ultimate load carrying capacity of RPC columns four input parameters were identified cross-section, micro steel fiber volume fraction content, compressive strength and main steel reinforcement area. Both models build with assistance of MATLAB software. The results exhibit that the cross section area has most significant effect on ultimate load carrying capacity. The performance of ANNs with different architecture was considered to adopt the pest ANN. An ANN with one layer consist of 7 neurons provide the best prediction. The results of this investigation indicate that ANNs have strong potential as statistical method for prediction the ultimate load carrying capacity of RPC columns. Keywords: Reactive powder concrete, artificial neural network, multiple linear regressions, ultimate load carrying capacity, Statistical analysis.
Issue No: Vol. 8
- Use of Portable Speed Humps Near Schools for an Obstruction-Free Traffic
Flow during Holidays
Authors: Chandrasekar Parsuvanathan
Abstract: Speed breakers or speed humps are known to provide road users with increased safety if strategically placed, especially in pedestrian intensive areas. Such traffic calming measures are common in land-uses where streets provide direct access to homes, hospitals, transit stops, and schools. In cities and towns of developing countries like India, it is common to construct at least two hump-like speed breakers, near the entry and exit gates of every school that provides primary, secondary and higher secondary education. The purpose of such speed breakers is to provide safety for students, staff and parents who access the school. However, as speed breakers are built as permanent structures, vehicles passing over them during non-operational hours as well as long holidays need to slow down for no reason. Portable speed breakers seem suitable for school areas to allow an obstruction-free traffic flow if and when possible. In this paper, results of a simulation evaluation of such portable speed breakers are presented, with quantification of benefits in terms of travel speed and travel time savings. Keywords: Speed breaker; speed hump; portable speed breaker; traffic calming; simulation modeling; traffic safety.
Issue No: Vol. 8
- Effect of Embedded Length and Bar Diameter of Reinforcement on Bond
Strength Behavior of High Strength Concrete Subjected to Elevated
Authors: Kushal Krishna Bastwadkar, Kishor S. Kulkarni
Abstract: In case of accidental fire, sabotages reinforced concrete structures get exposed to elevated temperatures, which results in deterioration of its mechanical strength. The deterioration in concrete is due to, its inhomogeneous volume change of concrete ingredients, generation of vapour pressure and decomposition of cement hydration products. Hence, it is significant to study the bond strength between concrete and reinforcing steel. In the present investigation a study has been carried out on bond strength between high strength concrete and reinforcing steel subjected to elevated temperatures. In order to find the variation in bond strength, various parameters were considered such as bar diameters, embedded length and different temperature levels with 1 hr retention period. In this investigation 12 mm, 16 mm and 20 mm diameter with two different embedded lengths 150 mm and 300 mm were adopted. Specimens were exposed to three different temperature levels 200°C, 400°C, 600°C with retention period of 1hr. The experimental results concludes that, under elevated temperatures, embedded length does not contribute more to change in bond strength, but bar diameter and temperature plays important role in change in bond strength and, which is also associated with statistical analysis. From experimental study an empirical formula is proposed to predict the bond strength by considering elevated temperatures, bar diameter and embedded length. Keywords: Bond strength, Bar diameter, Embedded length, Elevated Temperatures
Issue No: Vol. 8
- Durability of Ternary Blended Cement Concrete in Sulphuric Acid
Authors: OLUSOLA Kolapo Olubunmi, KOLAWOLE John Temitope
Abstract: This study investigated the durability of concrete made of ordinary Portland cement (OPC), bamboo leaf ash (BLA) and pulverized burnt clay waste (PBCW) as binders in sulphate environment. Ternary blending of OPC, BLA and PBCW at ten (10) levels (100:0:0; 90:5:5; 90:10:0; 90:0:10; 80:5:15; 80:10:10; 80:15:5; 70:10:20; 70:15:15; 70:20:10) were used in producing 480 concrete cubes of size 100 mm and cured for 28 days in water. Further exposure to sulphuric acid (H2SO4) of 0, 1, 3 and 5% concentrations was done for a maximum of 120 days. Strength deterioration factors were thereafter calculated as a measure of acid attack resistance for the blended cement concrete. Results show that concrete containing PBCW and BLA performed better in H2SO4 than that of the control. Therefore, it can be concluded that the incorporation of BLA and PBCW in concrete improved its durability in sulphate laden environment. Keywords:durability, sulphuric acid, bamboo leaf ash, pulverized burnt clay waste, strength deterioration
Issue No: Vol. 8
- Mathematical Models for Predicting Pollutant Transport in Soils at Decayed
Waste Dumpsites of Gwari Market, Yola, Nigeria
Authors: Burmamu; B. R., Law, P. L.
Abstract: Due to the careless siting of human activities in Nigeria, resultant pollutants pass through porous soils to pollute the underlying groundwater resources. Consequently Darcy’s Experimental set-up of Falling Head Permeability test was used to determine the velocities and travel distances of pollutants through soils leached from Gwari market waste dumpsites with a view to formulating mathematical equations for predicting the transport of pollutants through the porous soil media so as to safeguard the groundwater resources of the area. The dumpsite open year is (1999), 15 years old and spread on an area of 3.2 hectares with capacity of 60,000 tons. Results showed that the model advection velocity of 0.03845cm/sec. obtained is approximately equal to the observed laboratory velocity value determined as 0.03963cm/sec. Also, a model travel distance of 19.3cm obtained is approximately equal to an observed distance of 20cm determined in the laboratory. The analyses done implied that the models can be used to predict if pollutants from a dumpsite would travel to a river channel due to advection and dispersion processes within a specific given period which is a good pollution management strategy. The study recommended that in the planning and management of the physical environment, the knowledge of pollutants vertical velocity through porous soils should be integrated into water resources management for evaluating the effectiveness of pollutants mitigating alternatives, and in risk assessment to ensure environmental sustainability. Keywords: mathematical models, pollutants, vegetable dumpsites, velocity, transport.
Issue No: Vol. 8
- An Investigation into Factors Affecting the Performance of Public
Construction Projects in Ondo State, Southwestern, Nigeria
Authors: Helen Ifedolapo Babalola, Oyewale Julius Ojo
Abstract: This paper investigates the key performance indicators affecting Public Construction Projects in Akure, Ondo State Southwestern Nigeria. The study adopted a source technique with the administration of a well structured questionnaire to professionals in the construction industry. Descriptive statistical techniques such as frequency distribution, percentages and Relative Importance Index (RII) were used to analyze the data. The study revealed the top ten (10) most important factors influencing the performance of construction projects in Akure. These factors included: delay in progress payment to Contractors, Client’s interference during construction, Client’s inability to brief the project objectives and escalation of materials prices. Other factors were Client’s experience whether he is sophisticated or specialized; complexity of project; motivating skill of the project team leader; project team leader experience; Contactors commitment to ensure construction work is done according to specification as well as Client’s inability to make project decision. The paper concluded that the Contractors and Clients performance of the industry is below expectation. Keywords: Construction projects, Escalation, Performance, Public, Ranking
Issue No: Vol. 8
- Perception and Interpretation of Components of Architectural Composition
of Selected Urban Centres - Jos Metropolis, Nigeria
Authors: SATI; Yohana Chanle, OLA-ADISA, Erekpitan Omoikhefe, MANGDEN, Y. P. Elijah
Abstract: The study investigated the perception and interpretations of components of architectural composition of selected urban centres of Jos metropolis with the view to develop a planning strategy that will provide policy makers, architects and planners in emerging the necessary policies of urban planning and design. This concept was the focal problem the study sought to investigate scientifically. By dint of the simple random sampling, the study selected five neighbourhoods out of the existing eight namely; Anglo-Jos ward, Tudun Wada ward, Tafawa Balewa ward, Vander Puye ward and Zaria Crescent ward. From the five selected wards a total sample of 365 respondents was determined as the sample size for the investigation. Structure interview were employed in obtaining the required data of the perception and interpretations of components of architectural composition of selected urban centres of Jos. The outcome of the investigations provides a basis for notional significances, perceptual awareness, and planning instruments that can sustain the improvement and development of infrastructure and resources of the built environments of Jos urban centres and perhaps Nigerian urban centres. Keywords: perception, interpretation, urban centres, components and architectural composition
Issue No: Vol. 8
- The Effect of Operating Conditions on the Performance of a Vacuum Membrane
Distillation Unit Using PES Flat Sheet Membrane
Authors: Adel Fayez Gaid, Minerva Edward, Heba Abdallah, Khaled Zaher Abdallah
Abstract: The desalination of seawater is considered a promising source of potable water in Egypt. Vacuum Membrane Distillation (VMD) is a new separation technology based on the evaporation of saline water through hydrophobic porous membranes by applying vacuum pressure on the permeate side of the membrane to desalinate brackish or seawater. A lab scale experimental model was constructed and operated using hydrophobic polyethersulfone flat sheet membrane (PES) with effective area of 0.049 m2, pore size 0.2-0.4 µm and thickness 120-160 µm. Salt concentration ranging from 5000 ppm to 35000 ppm aqueous NaCl. Resultant permeate flux was measured for the following operating conditions: feed flow temperature (40-50-60-70 °C), flowrate (1-1.2-1.4-1.6 L/min), and vacuum pressure (0.2-0.3-0.4-0.5 Bar). Results showed an increase in permeate flux due to increased temperature, flow rate and vacuum pressure, while it decreased with the increase in salt concentration. The flux value obtained reached 15 kg/m2.hr at T= 40°C, vacuum pressure= 0.4 bar, TDS= 5000ppm, and flow rate 1 L/min, while it reached 29 kg/m2.hr at T= 70°C, vacuum pressure= 0.5 bar, TDS= 35,000 ppm, and flow rate 1.6 L/min. Electric power consumed by the system reached 0.612 Kwh at T=70°C, TDS =5000ppm, vacuum pressure = 0.4 bar, and feed flow rate 1 L/min. Keywords: VMD, desalination, vacuum pressure, hydrophobic membrane.
Issue No: Vol. 8
- The Impact of Urban Form Characteristics on Carbon Mitigation Process in
Authors: Adil Zamil Manshad Al-Saidi
Abstract: Cities are the main emitters of carbon dioxide and other greenhouse gases (GHGs) that cause the most dangerous phenomenon on the planet which is climate change. The research in how to reduce the effects of this phenomenon should have the priority especially by urban planners and designers. It is known that cities form just 2% of the total earth area but they consume more than 75% of the total energy and release more than 80% of GHGs. Although, there is a rich body of research to reduce carbon emissions from cities, the relationship between carbon mitigation process and urban form characteristics still needs more research work. So, the research gab that should be covered by this paper is; there is a need to address the role of urban form characteristics as a crucial factor in carbon mitigation process at a city scale. In other words, this research attempts to answer this main question:Can a link between carbon mitigation process and urban form characteristics be founded? This research aims to determine the relationship between the urban form characteristics and the carbon mitigation process in cities.Many cities have already made their carbon mitigation processes. This paper analyses and focuses on the urban form characteristics that have had an impact in the accounting and processing carbon emissions indirectly in these cities. So, this research needs to verify why these emissions in these particular areas are different based on our own thesis which is there are different urban form characteristics that affect the amount of emissions and the mitigation process required. To explain this impact, the research has analysed many cases of carbon mitigation processes in cities and has concentrated on the large cities in three main continents which are Asia, Europe and the North America.This research has analysed models, tools and techniques for urban carbon and energy modelling and has evaluated their relationship with cities’ urban forms. It has determined urban form characteristics by either studying urban form characteristics separately or studying the previous carbon mitigation efforts that mentioned some of urban form characteristics. This paper has presented the role of urban form characteristics in carbon mitigation process in the cities under review. It has identified common characteristics of urban form that are repeated as factors in plans and strategies of carbon mitigation. Keywords: Carbon mitigation process, urban form characteristics, greenhouse gases (GHGs), climate change
Issue No: Vol. 8
- Management Problems Associated with Multi-Tenanted High-Rise Commercial
Buildings in Kaduna Metropolis, Nigeria
Abstract: It is globally established that, where high-rise buildings are put in to multiple occupations, certain problems arise which eventually affect the building structure, occupants and the surrounding natural environment either directly or indirectly. This paper is aimed at investigating and presenting research findings on the management problems of multi-tenanted high-rise commercial buildings in Kaduna metropolis as compared to the system practised in other countries. Field survey was carried out and eventually structured questionnaire was employed as the data collection instrument. A total of 400 questionnaires were administered to the tenants, managers and owners of the buildings in the study area. Data obtained from the study were analyzed in tabular forms, simple percentage distribution tables and narrative description. Part of the results showed that 74% of the buildings were constructed 30 years ago which turned them old for the existing demands due to lack of upgrading the facilities therein. It was further uncovered that 66% of the facilities in the high-rise buildings such as lifts, generators, water supply were not properly maintained by the managing firms due to lack of planning and also due to lack of enough fund budgeted to take good care of maintenance activities. It was concluded that, old facilities are responsible for the void and vacant spaces in 44% of the high-rise buildings studied. It was deduced that facilities in the high-rise buildings failed to function regularly due to poor maintenance planning and ignorance of some managers to respond to repairs and maintenance request on time. Finally, part of the recommendations proffered include; property management rules of service should be adhered to, where only competent skilled workers will be employed to take care of different services provided in the multi-tenanted high-rise buildings. These competent hands should be adequately employed for effective management of the buildings. There should be good planning in respect of assessing and responding to sudden breakdown of services so as to achieve service delivery promptly. Keywords: Commercial Buildings, High-rise Buildings, Management Problems, Multi- tenanted Buildings and Property Management.
Issue No: Vol. 8