Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (C_m) and Power Coefficient (C_p) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of C_p was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

Background: High permeable concrete is designed with high porosity, which allows water to pass through it. By considering this ability, it has been widely used for various applications including high permeable road pavement. However, to fully adopt highly permeable road pavement technology is challenging due to high cost and maintenance, besides the present engineers and contractors have insufficient expertise and experience with this technology. Henceforth, the high porosity property is highly favorable for road curb applications especially in the tropical region like Malaysia with high rainfall intensity. Objective: This paper aimed to determine the properties of the concrete experimentally, and propose the optimum mix design of high permeable concrete for road curb. Methods: The flow value and setting time of the cement paste were investigated. Next, the effects of the modified high permeable concrete with varying amount of crumb rubber on compressive strength, permeability and void ratio were also investigated. Results and Conclusion: Results have revealed that the workability of the cement paste increases when the water-binder ratio and the amount of fly ash increase. Meanwhile, an increasing amount of cement ratio and crumb rubber lowers the flow value and consequently leads to lower void ratio and permeability. Besides, it has been found that the higher the compressive strength, the lower the void ratio and permeability of the concrete. The research findings support that using an optimum amount of cement replacement with crumb rubber as an additive may increase the performance a high permeable concrete. Herein, the results indicate that the mix design of the concrete studied has the potential to be applied onto the road curb.

Many researchers have computed the bearing capacity of the strip and circular footings resting on the soil with the low and medium friction angle (ϕ ≤ 35°) by employing the finite-element method (FEM). It is reported that the numerical instability occurs with the high value of ϕ. Thus, based on the suggested values of soil dilation angle (ψ) in this study, the numerical computation can be achieved for all ϕ. Therefore, this paper presents the computation of the vertical bearing capacity factors N_c, N_q, and N_γ of a rough conical footing placed on the soil with friction angle ranging from ϕ = 5° to 45° by using the FE-based viscoplastic strain method under the Mohr–Coulomb (MC) yield criterion. The numerical simulations are solved using in-house MATLAB codes. The effects of the cone apex angle (β) and ϕ on the bearing capacity are examined thoroughly by the computation of factors individually and compared with the available solutions. The current solutions are found to be in good agreement for N_c, N_q, N_γ values; however, the discrepancies are also observed and presented. Therefore, the bearing capacity factor charts are established, and, consequently, the ultimate load of the footing can be determined by using the superposition assumption in Terzaghi’s equation.

Our world has been relying on fossil fuel, a non-renewable energy that is depleting day by day and negatively impacting the environment. Hydropower is known to contribute a significant portion of the renewable power production. Dams has been the most common technique to generate hydropower. However, such scheme was not able to support the rural areas as it requires large areas and huge amount of water resource. Savonius hydrokinetic turbine (HKT) has been suggested as the device for a small-scale application as it can generate power from low-velocity river flow with less installation cost. With that, the aim of this study is designed to investigate and compare performance of the single-staged and two-staged HKT for river flow. This study considered numerical simulation that includes modelling, testing, and analyzing the data. Then, comparing it with the existing literature results, to identify the solution. This investigation demonstrates an improvement of 8.1% in the efficiency of power coefficient when compared with single-staged HKT.

In Malaysia, the Stormwater Management Manual for Malaysia (Manual Saliran Mesra Alam or MSMA) was introduced to manage stormwater and solve water-related problems. However, massive development caused the conventional stormwater system to be unable to cater to the excessive runoff and led to flooding, also affecting residential areas. This shows that there is an urgent requirement for a sustainable stormwater management practice (SSMP) in residential areas. This study is conducted to evaluate stormwater practitioners’ opinions on the proposed SSMPs, including green roofs, rain gardens/bioretention systems, and porous pavements, based on Strength, Weakness, Opportunity, and Threat (SWOT) factors through surveys and correlation analysis. The questionnaire was distributed to 14 branches of the Department of Irrigation and Drainage (DID), 14 branches of the City Council, and 28 selected private engineering companies. In total, 118 respondents were targeted to obtain their perspectives on the SWOT factors for each selected SSMP according to the Likert scale. The survey showed that the respondents agreed with most of the SWOT factors on the selected SSMPs. The results of the distributed questionnaire were used as the data for the correlation analysis. The analysis indicated that green roofs, rain gardens/bioretention systems, and porous pavements have a strong positive relationship, with a p-value of less than 0.05 for the Strength and Opportunity factors, and a weak positive relationship, with a p-value of more than 0.05 for the Weakness and Threat factors. This shows that the proposed SSMPs are suitable to implement in residential areas. Observations were conducted to obtain the residents’ opinions on the performance of stormwater management in their residential areas and to evaluate the suitability of the proposed SSMPs to be implemented in the observed areas. Based on the observations, it can be concluded that only rain gardens/bioretention systems and porous pavements are suitable when compared to green roofs. An interview session was conducted with practitioners in stormwater management to gain their opinions on the studies and the proposed SSMPs. The interviewees agreed with the issues and that the SSMPs should be implemented in landed residential areas.