|Author(s): A. I. Al-Ghonamy, M. Ramadan, N. Fathy, K. M. Hafez, A. A. El-Wakil|
|Pages: 1-4||Paper ID: 101603-5959-IJCEE-IJENS||Published: June, 2010|
Abstract: Waterworks fittings and accessories are important applications for ductile irons. Although, in the design of these components the graphite nodularity is a critical attribute for material selection, the International Standard ISO 2531 does not include the minimum required value of graphite nodularity and its definite effect on mechanical properties. In this research the effect of graphite nodularity on tensile strength, elongation, impact strength and wear rate was studies. Different samples from four heats of cast iron containing several of graphite nodularities were cast. Different degrees of graphite nodularities from low graphite nodularity of about 21% up to high graphite nodularity of 94% were produced by treatment cast iron by different amount of spheroidizing (Mg) and antispheroidizing (Ti) elements. It is concluded that all properties relating to strength and ductility decrease as the graphite nodularity increase, and those properties relating to failure, such as tensile strength and impact strength are more affected by changing of graphite nodularity. The minimum graphite nodularity of 60% can be considered for design as satisfactory values of ductile iron fittings and accessories for all DN values.
|Keywords: Graphite nodularity, mechanical properties, ductile iron, fittings.|
|Full Text (.pdf) | 291 KB|
|Author(s): Ammar Rouaiguia|
|Pages: 5-14||Paper ID: 103003-2828-IJCEE-IJENS||Published: June, 2010|
Abstract: The interface between structures and soils is a critical problem in geotechnical engineering. Understanding the shear strength of soil-structure interfaces is important in determining wall or shaft friction for retaining walls and piles, anchor rods, deep foundations, reinforced earth, and buried pipelines. This study deals with laboratory tests on six different clays, three Algerian clays namely: Kaolin1, Kaolin2, and Kaolin3. Three British clays namely : Keuper marl, London clay, and Lias clay. The testing procedures included modified direct shear tests. Each clay was sheared alone, under normally consolidated drained conditions, and against both Sandstone rock and glass. These tests defined the minimum residual strength obtained in each case and provided a basis for a comparison with other published research. It is demonstrated that the residual strength depends mainly on the interface material and its roughness, the properties of the soil, and the magnitude of the clay fraction. The minimum value of residual strength was obtained with the clay sheared against glass. It is concluded that the shear-displacement behaviour of clay-structure interface is similar to that of soil-on-soil.
|Keywords: Residual shear strength, laboratory tests, modified shear box apparatus, soil-structure interfaces.|
|Full Text (.pdf) | 678 KB|
|Author(s): Othman Che Puan, Che Ros Ismail|
|Pages: 15-20||Paper ID: 104803-5757-IJCEE-IJENS||Published: June, 2010|
Abstract: Installation of traffic signal control system at relatively high traffic volume intersections is expected to safeguard drivers at such intersections by providing a clear definition of right–of–way to drivers. However, a particular operational issue is the existence of dilemma zone conflicts if the type traffic signal system installed is not properly selected and designed. The problem is critical for isolated intersections on relatively high speed road sections. This paper describes result of a study carried out to investigate the existence of dilemma zone conflicts at isolated intersections installed with various types of traffic signal control systems. Three indicators of dilemma zone conflicts considered in the analysis are (i) stop abruptly; (ii) accelerate through amber period; and (iii) red–light running. Data pertaining to the analysis of dilemma zone conflicts was collected at eight isolated intersections with different types of traffic signal control systems using a video–recording technique. The data includes vehicles’ approaching speed, distance from the stop line at the onset of amber, the decision made by the drivers at onset of amber as well as the types of vehicles driven. The result shows that relatively large proportion of drivers did not willing to stop at onset of amber signal. A vehicle–actuated traffic signal system appears to perform better compared to other types of system in terms of reduction in dilemma zone conflicts at isolated signalized intersections.
|Keywords: Driver’s decision, amber period, dilemma zone, red–light running.|
|Full Text (.pdf) | 344 KB|
|Author(s): Abdel-moniem El-Shorbagy|
|Pages: 21-26||Paper ID: 105403-6868-IJCEE-IJENS||Published: June, 2010|
Abstract:The traditional architecture of Central Asia and the Middle East is the product of land, the local climate, and people’s culture. The human needs and the environment represented the most essential factors to be considered in their designs. The traditional and vernacular architecture of this region introduced many realistic solutions and devices to the local environmental problems such as the Wind-catcher, which became a common architectural feature in buildings. The wind-catcher is based on a traditional Persian architectural device, which was used to create natural ventilation in buildings. Since the energy crisis of the 1970s, the ecological or sustainable architecture movement dominated architect’s thoughts of realising buildings that are environmentally relevant to their regions. In recent decades, there has been an increasing awareness of these traditional environmental devices and their potential for possible future buildings. However, traditional and vernacular architecture, which considered the human needs and the environment, provided many realistic solutions to the more recent modern environmental problems. This paper demonstrates the value of wind-catchers and provides insight into the application of natural ventilation systems as an alternative to the inappropriate modern cooling system in hot-climate regions. It also aims to examine the theoretical status of wind-catchers and to identify its specific nature, its use and its function in the context of architectural practice and discourse, in the past, present and future.
|Keywords: Wind-catchers, Natural cooling, Sustainability, Technology.|
|Full Text (.pdf) | 821 KB|
|Author(s): Ahmed T. Khairy, Abdullah S Al-Ghamdi, Saud A Gutub|
|Pages: 27-35||Paper ID: 107602-03-5353-IJCEE-IJENS||Published: June, 2010|
Abstract:A 3-D finite element (FE) numerical model was used to analyze structurally a proposed subsurface concrete dam to serve as a strategic water supply storage for the Holy city of Makkah, Saudi Arabia. The work was done mainly to show the behavior of the subsurface dam under the subjecting loads. The plastic concrete was chosen for the construction of the cut-off wall required for the reservoir. Three-dimensional finite element analyses were made for three thicknesses of the cut-off walls: 0.6 to 0.8 m, 0.8 to 1.0 m and 1.0 to 1.2 m for the alluvium depths of 30, 50 and 70 m, respectively. The change in soil rigidity with depth was taken into account. The vertical and horizontal boundary conditions were designed to simulate the proper behavior of the structure It was found that increasing the thickness of the wall improves the distribution of the mobilized passive pressure opposite to the water pressure acting on the upstream face of the cut-off wall, while, the vertical and horizontal stresses developed in the wall due to the applied loads increased. In addition, stresses in the wall increase incrementally with the increase of wall height. The maximum horizontal and vertical stresses developed in proportion to the 1/6 bottom height of the wall. In the lower part of the wall, the mix with rich cement content must be used. It is recommended also to use vertical reinforcement imbedded by the anchorage length in the lock of the wall inside the bedrock and extended 1/20 the wall height. Results showed that the two vertical boundaries in the FE mesh must be placed at minimum distance equaling twice the height of the alluvium deposits from the centerline of the cut-off wall.
|Keywords: Subsurface dam analysis, cut-off wall analysis, underground dam analysis, structural analysis of dams.|
|Full Text (.pdf) | 667 KB|