3D numerical modelling of shallow tunnel in weathered granite incorporating multi-stage excavation and pre-support

Generally tunnelling in urban ground condition is not always favourable due to the tunnels’ susceptibility to major displacement especially when excavated in the soft soil and/or weak weathered rock formation. Apart from conventional support systems, pre-support measure like forepoling umbrella arch is frequently used to reinforce the ground. Modern computational tools allows the inclusion of multi-stage excavations and pre-support which was not possible in two dimensional (2D) plane strain. This paper demonstrates the three dimensional (3D) finite element analysis of Pahang-Selangor raw water transfer tunnel, as a reference case, where multi-stage excavation and pre-support are incorporated as intrinsic part of the model. The New Austrian Tunnelling Method (NATM)-3 segments which encountered Grade III weathered granite, having shallow overburden cover, was selected for numerical analysis using RS3 software. Comparison between simulated and observed data has shown good agreement during verification

Development of Hybrid Photovoltaic-Wind System for LED Street Lighting

This paper presents the development of hybrid Photovoltaic (PV)-Wind system connected to light emitting diode (LED) street lighting as the load. The aim of this research is to analyze the energy performance from the combination of PV system and wind system which is hybrid system to the LED lamp as the load. In this project, the PV panel and wind turbine used to generate the energy and the output of the energy control by two equipments which are solar charger controller and hybrid charger controller. The output of both PV and wind connected with the battery as storage energy for this system. In this research, the PV system produces the best energy compared to the wind system and it is reliable to charge the battery of the system and supply to the loa

Process optimisation of effective partition constant in coconut water via progressive freeze concentration

Concentration technique via progressive freeze concentration was applied to increase the concentration of coconut water for commercialisation. The process will eliminate portion of water from coconut water and retain pure nutritional compound with high sugar content. To obtain the optimum condition, which is the objective of this study, optimisation process was conducted using Response Surface Methodology (RSM) through STATISTICA Software. RSM was utilised to optimise the process parameters for effective partition constant (K) in progressive freeze concentration (PFC) of the coconut water. The effects of circulation flowrate, circulation time, initial solution concentration and coolant temperature on effective partition constant were observed. Results show that the data adequately fit the second-order polynomial model. The linear and quadratic independent variables, circulation flowrate, circulation time, initial concentration and coolant temperature have significant effects as well as interactions on the effective partition constant. It was observed that the optimum process parameters within the experimental range for the best K would be with circulation flowrate of 3,400 mL/min, circulation time of 23 min, initial concentration of 3.4 % Brix and coolant temperature of -7 °C. Under these conditions, the K can be enhanced up to 0.3

A simulation model of reinforced concrete beam containing expanded polystyrene beads (EPS) and palm oil fueled ash (POFA) using finite element method

In this study, Expanded Polystyrene bead (EPS) and Palm Oil Fuelled Ash (POFA) will be used to replace several percents of cement and aggregate in reinforced concrete beam construction. EPS can produce lightweight concrete, and the use of POFA can produce high strength concrete and can also reduce waste disposal. The reinforced concrete beams were analysed using computer software called ABAQUS. The main reason Abaqus software is used as analytics software for this project is that the software is designed specifically for analyzing advanced structural and heat transfer. It is designed for both linear and nonlinear pressure analyses for both tiny and huge structures. This software can also be used to analyze the proposed reinforced concrete beam failure pattern of EPS and POFA. The percentage of EPS and POFA were 40% to 60% in concrete as replacement material. The information obtained from Abaqus is then used to verify the experimental results. The data also contains the appropriate percentage of EPS and POFA in the reinforced concrete beam where performance in terms of bending, pressure, and failure pattern is at maximum. The result shows decrease performance of RC beam containing 40-60% EPS and POFA

Cleaner Production Implementation using Extended Value Stream Mapping for Enhancing the Sustainability of Lean Manufacturing

This paper investigated the measures by Cleaner Production (CP) embedded in the modified VSM technique, i.e., Cleaner Production VSM (CPVSM) to be an effective visualisation technique for Lean and promoted the sustainability at 2 local Small and Medium Enterprises (SME’s) for demonstrating the level to which the CPVSM process can be applied. Our findings showed that the implementation of the CP technique was improved through this CPVSM approach and thus promoted the Lean Manufacturing (LM) sustainability

Carbon footprint of construction using industrialised building system

Industrialised Building System (IBS) is more sustainable to the environment as compared to the conventional construction methods. However, the construction industry in Malaysia has low acceptance towards IBS due to the resistance to change and also lack of awareness towards sustainability development. Therefore, it is important to study the amount carbon footprint produced by IBS during its manufacturing and construction stage, and also the amount of carbon footprint produced by one meter square of gross floor area of IBS construction using Life Cycle Assessment (LCA) to ease future research through the comparison of the carbon footprint of IBS with the conventional building system. As a result, a case study on a residential type of construction in the vicinity of Johor Bahru, Malaysia was carried out to obtain the necessary data and result. From the data analysis, the amount of greenhouse gases (GHG) for a residential type IBS construction based on the raw materials and resources involved to manufacture and construct IBS components is 0.127 tonnes fossil CO2Eq per meter square. Raw material that contributed to the most amount of carbon footprint is Ordinary Portland Cement (OPC), followed by steel bars, autoclaved aerated blocks and diesel. The LCA data acquired will be very useful in implementing IBS in the residential type construction. As a result, the awareness towards sustainable construction using IBS can be improved

Comparison of non-mydriatic fundus photography and optical coherence tomography with dilated fundus examination for detecting diabetic retinopathy including diabetic macular edema

Given increasing diabetes rates worldwide, better screening tools for diabetic retinopathy (DR) and macular edema (DME) are needed. The study aim was to compare reliability and predictive values between non-mydriatic fundus photography (NMFP) and spectral-domain optical coherence tomography (OCT) for detection of DR and DME with dilated fundus examination (DFE). This was a non-interventional, comparative study. Diabetics underwent both NMFP and macula OCT, followed by DFE. Images were interpreted by two masked ophthalmologists. The DFE result was considered gold standard. One hundred and fifty-four eyes of 83 patients were recruited. Sensitivity of NMFP for DR was 77.3% and 80.3% for OCT. Specificity for NMFP was 81.8% and 55.7% for OCT. Area under Receiver Operating Characteristics Curve (AROC) for DR was 0.80 for NMFP and 0.68 for OCT. The sensitivity of NMFP for DME was 63.2% and 82.5% for OCT. Specificity for DME was 90.1% by NMFP and 61.5% for OCT. Positive predictive value (PPV) of NMFP and OCT for DR was 76.1% (95% CI: 63.9-85.3%) and 57.6% (46.8-67.7%), respectively. Negative predictive value (NPV) of NMFP and OCT was 82.7% (95% CI: 72.8-89.7%) and 79.0% (66.4-87.9%) respectively. Positive predictive value of NMFP and OCT for DME was 80.0% (95% CI: 67.6- 88.5%) and 57.3% (45.9-68.0%), respectively. Negative predictive value of NMFP and OCT was 79.6% (95% CI:70.3 - 86.7%) and 84.8% (95% CI:73.4 - 92.1%), respectively. Eyes with normal OCT miss 21% of DR. In conclusion, NMFP is better than OCT for DR screening, while OCT is better than NMFP and DFE for detection of DME. Both modalities should be for better DR screening

Improving sustainability of road construction by partial replacement of natural aggregates in subbase layer with crushed brick and reclaimed asphalt pavement

Reducing dependent on naturally sourced materials is among the priority in improving the sustainability of road construction. The subbase layer which provides strength and stability across the road profile, comprised mainly of natural aggregates. This study aims to explore the feasibility of partial replacement of natural aggregates in subbase layer with 20% Crushed Brick (CB) and 20 to 50% Reclaimed Asphalt Pavement (RAP). California Bearing Ratio (CBR) test and Constant Head Permeability tests were carried out to determine the effect of this partial replacement on the geotechnical properties of the subbase layer. The results obtained denotes that the combination of 20% CB and 50% RAP is the optimum partial replacement of natural aggregates in subbase layer with CB and RAP. The use of CB further complements RAP in improving the stiffness and compressibility of the subbase layer while contributing significantly toward sustainability in road construction