Badronnisa Yusuf

Bio: Badronnisa Yusuf is an academic researcher from Universiti Putra Malaysia. The author has contributed to research in topics: Pier & Stormwater. The author has an hindex of 9, co-authored 57 publications receiving 390 citations.

Flow and sediment transport in vegetated waterways: a review

Abstract: One of the most important waterway components is vegetation, which play a pivotal role in the flow and sediment transport. Vegetation environment and characteristics, including vegetation porosity or density, shape, flexibility and vegetation height, are significantly affected in vegetated channels. Various vegetation positions and arrangements such as patches significantly affect the sediment deposition rate and flow turbulence. This paper reviews recent works conducted on vegetated open channels, which include the effect of different vegetation arrangements and vegetation characteristics on mass transport and turbulence structure. Studies based on laboratory, field works, and modeling, have been reviewed based on previous methods used by different researchers. Methods used in vegetation porosity evaluation, rate of flow and sediment transport properties are presented. In short, flow and transport depend on the vegetation properties and flow structure conditions.

Manning roughness coefficient for grass-lined channel

Abstract: A laboratory study has been conducted to analyze the effects of different types of vegetation on the Manning roughness coefficient, n in an open channel, and to develop relationships between the characteristics of the vegetation (density, degree of submergence and distribution) and Manning's, n. Two type of vegetation were used in this study, namely Napier grass and Cattail grass. The impact of each type of vegetation on the resistance of flow in open channel (Laboratory flume) was examined. The laboratory flume is rectangular in cross section and has dimensions of 12 m length, 0.3 m width and 0.3 m height. An area-velocity flow meter was used to measure the mean velocity, and Manning's equation was adopted to determine the value of overall roughness, n. The results show that Manning's, n, for flows with Napier grass increased with the increase in flow depth for both submerged and unsubmerged conditions. The increment in Manning's, n was found to be 282% when the degree of submergence (Y/H) for high grass density increased from 0.5 to 0.875. In the presence of Cattail grass and for high density, the effects were reversed and the decrease in Manning's, n was found to be 41% for same increase in degree of submergence. This is attributed to the physical characteristics of the Cattail grass, which has no branching stems and leaves. For low density of Napier grass, the values of Manning's, n decreased with the incerase of Reynolds number, Re, for both submerged and unsubmerged vegetation. Howerver, for a higher density, this phenomenon only occurred for submerged vegetation. In the case fo unsubmerged vegetation the values of Manning's, n increased with the increase of Re. But for Cattail grass, the values of Manning's, n decreased with increase of Re for all grass densities and for submerged and unsubmerged flow conditions. A linear relationships were found between Manning's, n and grass density for both submerged and unsubmerged flow conditions and the coefficient of determination for the relationships ranges form 0.93 to 0.96. When the density increased form 20 veg/m 2 to 40 veg/m 2 the value of Manning's, n increased by 35% for Napier grass and 25% for

Mitigation and Adaptation Strategies for Global Change

Abstract: ▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

Passive solar high-yield seawater desalination by modular and low-cost distillation

Abstract: Although seawater is abundant, desalination is energy intensive and expensive. Using the Sun as an energy source is attractive for desalinating seawater. Although interesting, current passive devices with no moving parts have unsatisfactory performance when operated with an energy flux lower than 1 kW m−2 (one sun). We present a passive multi-stage and low-cost solar distiller, where efficient energy management leads to significant enhancement in freshwater yield. Each unit stage for complete distillation is made of two hydrophilic layers separated by a hydrophobic microporous membrane, with no other mechanical ancillaries. Under realistic conditions, we demonstrate a distillate flow rate of almost 3 l m−2 h−1 from seawater at less than one sun—twice the yield of recent passive complete distillation systems. Theoretical models also suggest that the concept has the potential to further double the observed distillate rate. In perspective, this system may help satisfy the freshwater needs in isolated and impoverished communities in a sustainable way. Solar desalination is an attractive alternative to energy-intensive conventional seawater desalination. In this study, the authors present a completely passive, multi-stage and low-cost distiller using layers of membranes to achieve a distillate flow rate of almost 3 l m–2 h–1.

Experimental and Numerical Analysis for Earth-Fill Dam Seepage

Abstract: Earth-fill dams are the most common types of dam and the most economical choice. However, they are more vulnerable to internal erosion and piping due to seepage problems that are the main causes of dam failure. In this study, the seepage through earth-fill dams was investigated using physical, mathematical, and numerical models. Results from the three methods revealed that both mathematical calculations using L. Casagrande solutions and the SEEP/W numerical model have a plotted seepage line compatible with the observed seepage line in the physical model. However, when the seepage flow intersected the downstream slope and when piping took place, the use of SEEP/W to calculate the flow rate became useless as it was unable to calculate the volume of water flow in pipes. This was revealed by the big difference in results between physical and numerical models in the first physical model, while the results were compatible in the second physical model when the seepage line stayed within the body of the dam and low compacted soil was adopted. Seepage analysis for seven different configurations of an earth-fill dam was conducted using the SEEP/W model at normal and maximum water levels to find the most appropriate configuration among them. The seven dam configurations consisted of four homogenous dams and three zoned dams. Seepage analysis revealed that if sufficient quantity of silty sand soil is available around the proposed dam location, a homogenous earth-fill dam with a medium drain length of 0.5 m thickness is the best design configuration. Otherwise, a zoned earth-fill dam with a central core and 1:0.5 Horizontal to Vertical ratio (H:V) is preferred.