Chief Editor:

Professor Dr Chin Leo

International Journal of Engineering, Construction and Computing (IJECC)

Current Issue: Volume 1 Issue 1

Abstract: For the safety management of CWR track, the primary is to obtain the accurate neutral temperature of the CWR track (i.e. the value and distribution of the longitudinal stress within the rail). In the recent decade, some newly developed technologies have been utilised for the non-destructive neutral temperature measurement. The Magnetic Barkhausen Noise (MBN) technology is one of them. Within this paper, a series of in-field verifications and data comparison results which are obtained on Australian heavy haul mainline tracks are presented. These results have shown that this MBN measurement system can provide high accurate and reliable neutral temperature results. By using this effective measurement tool, the neutral temperature on several critical rail lines has been measured. Among these lines, the track structures and conditions are in high diversity. To study the details of the longitudinal stress distribution within the variable CWR tracks, the non-linear finite element analysis modelling is utilised to simulate the track conditions, ambient temperature changing and structural features.The major outcomes from this study including: Firstly, the fastening system and sleeper spacing for a specified CWR track module can significantly impact to its stability. Secondly, for the CWR tracks which are installed on the sharp curves and steep slope, the neutral temperature (longitudinal stress) is not evenly distributed within the CWR module. Thirdly, bending stress in the rails that installed on the sharp curves can influence the thermal stress distrib ution in the longitudinal direction and it seems it is sensitive with the radius of the curve. Download

Abstract: This paper presents an experimental and numerical study on square hollow section (SHS) T-joints (t≤4 mm) subjected to in-plane bending (IPB) on the brace. In the experimental investigation, strain gauges were used to measure the strains and determine the stress concentration factor (SCFs) at the potential hot spot locations (Lines A-E) for each SHS-SHS T-joint specimen. The numerical study was performed by developing three-dimensional finite element models through the use of ABAQUS software to capture the distribution of the SCF at the weld toes. In this investigation, the empty T-joints are made up of an empty SHS brace and empty SHS chord member. Six empty SHS-SHS T-joints were tested and modelled under static in-plane bending load. The maximum experimental and numerical SCFs will be compared with the SCFs obtained from CIDECT Design Guide 8. There is a good agreement between the numerical results and the experimental results for each identical T-joint connection. This paper provided additional results for smaller β values and larger β values. Results show a similar trend of the variation of SCF with β from experiments and numerical analysis. Download

Abstract: Prefabricated construction has been rising dramatically in the construction industry in recent times. On the other hand, it is equally complicated and laborious to design and install the prefabricated structures on site. The reason behind this can be credited to the limited design guidelines available and the massive structural parts. This research has been carried out to overcome shortcomings of the prefabricated composite construction. In this paper, the idea of discontinuous beams and a beam-to-beam connection system has been proposed for the prefabricated construction. Modified splice plate bolted connection has been suggested for the discontinuous beams. The proposed connection is similar to splice plate bolted connection, but welding between splice plate and beam web is introduced. This paper mainly investigated the behaviour of modified splice plate bolted connections using finite element (FE) analysis and compared its results with continuous beam. Based on FE modelling results, it has been found that the proposed connection system having welding provides higher strength to the discontinuous beam compared to the same discontinuous beams connected by conventional splice plate bolted connection systems. Splice plates welded to the web of the steel beam need to be fabricated in a factory and normal bolts are installed on the site of the building construction. Thus, it can be concluded from this research that the massive continuous beams can be replaced by discontinuous beams through a presented connection system for prefabricated construction. Download

Abstract: The mechanical shaft is a key element in the majority of mechanical systems. It is responsible for delivering power from one end of the drive train to another. The rotating shaft undergoes rapid fluctuations of bending moment stresses and when combined with their long operational hours, it can eventually form a crack and thus lead to shaft failure. Therefore, it is imperative that a method is developed in order to detect cracks whilst the shaft is in motion. In this paper, an experimental analysis is conducted to obtain the bending stiffness values, and to contribute to the literature of rotor-dynamics so that eventually a method for early crack detection during dynamic operation can be developed. The experimental research involves the creation of cracked shaft models (0.1 mm wire cutting into the shaft, 0.3 mm wire cutting into the shaft, having two 0.3 mm wire cutting into the shaft and developing a 0.3 mm crack by welding joinery). This method of creating the cracked shaft models is relatively quick, easy and cost effective. A three-point-bending test is then conducted on the cracked shaft models to evaluate the shaft’s stiffness variation through varying angular positions. The results show that all the cracked shaft models exhibit the breathing mechanism corresponding to the cracks location during rotation. Download

Abstract: The mechanical shaft is a key component in most mechanical systems. It is in charge of transferring power from one part of the machine to another part. As the shaft spins over long operational hours it may become prone to forming a fatigue crack. Often cracks show no symptoms until the shaft reaches failure. It is with utmost importance to develop a method to detect a cracked shaft before it reaches failure. Modal analysis is the first step to reach the goal and understand the vibration behaviour of a machine. In this work, Finite Element analysis is performed to acquire the mode shapes from cracked shaft models developed through Abaqus. The models include various shafts, such as an intact shaft, a shaft with varying crack depth ratios [0.5, 1, and 1.5], crack locations and the number of cracks [1 and 2 cracks]. Each shaft model developed will have 5 modes tested and the natural frequency will be derived for each mode. Comparison of the frequencies shows that shaft stiffnesses are significantly reduced for a shaft with a larger crack, and also a shaft with more cracks. The results gathered are new and provide a contribution to rotor-dynamics for eventual development of a method for early crack detection. Download

Abstract: Urban agriculture and Rainwater Harvesting (RWH) have grown in popularity in recent years. The economic viability of RWH systems has been reported with various outcomes. The water demand profile is complex and of all domestic demands, outdoor irrigation use is the most variable and potentially the largest domestic use of potable water. Water for gardening, toilet and laundry does not need the high level of treatment that drinking and cooking water requires. The amount of water a RWH system can supply for these uses is influenced by the rainfall pattern, tank size and roof area. A versatile economic evaluation tool named ERain has been developed to analyse the economics of various RWH system arrangements. ERain combines performance analysis using daily rainfall data with life cycle cost analysis. Here ERain has been used to assess the effects of varying roof size or irrigation area on the economic viability of RWH systems for tank sizes ranging from 1-7kL. Results show that excluding outdoor use, the benefit cost ratio (BCR) increases with roof size along with reliability, while efficiency decreases. Interestingly, the larger roof area has the most significant effect in terms of reliability on the smaller tanks. Including outdoor use reduced reliability overall but increases both the efficiency and BCR indicating that it is better financially to use the RWH system for outdoor use when reliability is not a concern. The larger NPVs and BCRs occur with the larger irrigation areas as this increases water use and hence monetary water savings. Within the 1-7kL tank range, the 7kL tank is the most favourable when outdoor irrigation use is connected. Download

Abstract: This work theoretically investigates the effect of nanofluids on the energy and exergy efficiencies of a flat plate solar collector. Four different types of nanofluids, Al2O3/water, SiO2/water, TiO2/water and CuO/water, have been taken into consideration to examine the performance of the solar collector. The efficiencies are determined for a range of volume fractions of each nanoparticle and subsequently compared to each other. It is shown that the application of CuO/water nanofluid as a fluidic medium in a conventional solar collector can enhance its energy and exergy efficiencies by 38.46 and 15.52% respectively, when compared to water. The ultimate objective of the present study is to understand the feasibility of each kind of nanofluid prior to the application in solar to thermal energy conversion. Download

Abstract: The River Jamuna, in Bangladesh, is one of the greatest alluvial rivers in the world. Almost every year severe erosion takes place, which renders tens of thousands of people homeless. In order to improve the livelihoods of floodplain dwellers, understanding the morpho-dynamics of the river is essential. The reach boundaries considered in this study are 30 km upstream and 20 km downstream of Bangabandhu Bridge. The main objective of this paper was to look over the sediment dynamics and the possible changes on riverbed morphology by using the open-source, Delft3D modelling software. Water level and discharge were two important hydrological parameters that were used as the boundary conditions to investigate the erosion and deposition process. Variation of velocity, erosion and deposition, sediment transport and bed level changes of the Jamuna River were studied using this modeling suite. The frequency of erosion/deposition and shifting of the riverbank were predicted for two consecutive years (2011-2012). Comparisons were made between the simulated results of Delft3D with the results obtained from the Mike 21. Shifting of channels were observed, as erosion and deposition took place simultaneously along the channel bed and bank line. The knowledge regarding the shifting direction and magnitude of shifting generated from the analysis developed herein could be useful in the future projection of planform changes of braided rivers around the world that are similar to the Jamuna river. Download

Abstract: In the last decade, urbanization in the oasis city of Al-Hofuf, Saudi Arabia has considerably increased in terms of urban population, urban housing and the number of personal automobiles. Al-Hofuf is located in an arid region where different sources of atmospheric pollution occur including heavy oil combustion, suspended soil, industrial emissions, and traffic emissions. Air pollution in terms of carbon dioxide (CO2) and total volatile organic carbon (TVOC) was investigated to examine the impact of urbanization. Four key urban locations were selected for CO2 and TVOC measurement and results were compared with a rural site. Variation of population, housing units and number of cars were reviewed using available data and the trend of air pollution was observed. Results show that CO2 and TVOC are within the allowable limit in Al-Hofuf in spite of rapid urbanization in the last decade. The measured CO2 at all the sites varied in the range of 330-430 ppm and TVOC varied between 153 and 341 ppb. CO2 and TVOC showed an increasing pattern between 2014 and 2018, which is 1.1 times and 3.9 times higher respectively, in the four-year period. Based on the monitored data in five locations, spatial distribution of pollutants is proposed, which can be used to identify pollution hotspots in Al-Hofuf city. Download

Abstract: Flood is one of the worst natural hazards worldwide. Brisbane, Queensland, has experienced many severe flood events causing damages worth billions of dollar and human deaths. Accurate estimation of design floods with less uncertainty helps to minimise flood risk, damage and loss of human life. Among many design flood estimation methods, flood frequency analysis (FFA) is a widely used method. The primary step in FFA is the selection of a suitable probability distribution that fits the observed flood data adequately. As it is still not possible to select the best fit distribution from a large number of candidate distributions and associated parameter estimation procedures for a particular catchment with certainity, selection of probability distribution is still remain a difficult task. This study examines the selection of the best fit probability distribution for FFA. Brisbane River catchment of Queensland is selected as the study area. The annual maximum (AM) flood data from 26 stream gauging stations are selected with AM flood record lengths ranging from 20 to 91 years with a mean value of 47 years. Five different probability distributions and three goodness-of-fit tests are adopted. Based on a relative scoring method, Log Pearson Type III is found to be the most suitable probability distribution, followed by Generalised Pareto for the study area. To investigate the impact of high floods on the selection of the best fit probability distribution and flood quantile estimation, FFA are carried out twice; with the high flood values being included in the data and excluded from the data. It is found that the best fit probability distribution changes and magnitude of flood quantiles reduces notably if high floods are excluded from the data series. Download

Abstract: Water is vital source of life. In developed countries, we are extremely fortunate to be able to access water at our fingertips, with little cost. Consequently, our water use is so much that per capita, per day water demand in Sydney is about 303 litres. In contrast, about 1 billion of the world’s population does not have access to as little as 5 litres of safe drinking water per day. Access to safe drinking water is regarded as a basic human right, but to our surprise, approximately one-fifth of the world’s population does not have access to safe drinking water. Water is also an integral part of the eco-system. Educating our school students about water is important so that this precious resource is preserved and enhanced for all the human beings. This paper presents an overview of water education in New South Wales. It has been found that New South Wales’ school children receive basic education on water such as learning about the hydrologic cycle and water recycling but limited mathematical aspects of water management are taught. Due to climate change, increasing water demand and increasing pollution will make water accessibility a challenging issue in the near future. Water education will assist to achieve sustainable water development practices in Australia. Download

Abstract: The world’s water resources are increasingly being threatened with rapid urbanisation. A comprehensive water quality management program is necessary to protect the valuable freshwater resources and to safeguard public health. River water quality assessment mainly involves two components: measurement of water quality variables and comparison of measurements to benchmark with guidelines and water quality objectives to assess the degree of change and its impacts on aquatic environment and human health. Traditionally, water quality data is summarised in technical reports that are valuable to individuals who understand the technical content; however, this information is not always useful to non-technical individuals and community members. A Water Quality Index (WQI) provides a convenient means of summarising complex water quality data and facilitates its communication to a general audience. This paper presents the use of WQI to identify changes in river water quality over time, identify and assess deteriorated river sections and the water quality parameters which contributed to the deterioration and their relative contributions. The Hawkesbury Nepean River System (HNRS), which is the main source of drinking water supply to more than 4.8 million people living in and around Sydney, Australia, was assessed using a Canadian WQI. Water quality data obtained from 9 sampling stations along the HNRS during the last 21 years (1993 to 2013) were used to identify changes in water quality at different sampling stations over time, and to compare water quality parameters among the stations. The results provide an estimate of the overall water quality against the Australian and New Zealand Water Quality guidelines. It has been found that the overall water quality at the HNRS is at marginal to poor state. Download

Abstract: Internet of Things (IoT) together with Machine Learning has a great impact on the new era of technology. Technological advancement and invention of smarter devices are going neck and neck in today’s world. A common incident such as car accidents hampers the advancement of human life. Most common reasons for the accidents are - driver’s unawareness and uncontrolled speed of vehicle. We have developed an IoT based solution to detect and prevent such incidents. This paper focuses on a smart system that alerts and controls the speed of the vehicle. It measures real-time distance between vehicles and/or obstacles in front of the vehicle using Ultrasonic sensor. It controls speed of the vehicle and alerts respective individuals if an accident occurs. The core processing unit of the proposed system is Raspberry Pi incorporating Naïve Bayes Classifier. The proposed system is implemented and the experimental results show that the system works properly in different road traffic situations. Download

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