Ahmad Mustafa Hashim

NOVEL CONFIGURATIONS OF SOLAR DISTILLATION SYSTEM FOR POTABLE WATER PRODUCTION

More and more surface water are polluted with toxic chemicals. Alternatively brackish and saline water are used as feed water to water treatment plants. Expensive desalination process via reverse osmosis or distillation is used in the plants. Thus, this conventional desalination is not suitable for low and medium income countries. A cheaper method is by solar distillation. However the rate of water production by this method is generally considered low. This research attempts to enhance water production of solar distillation by optimizing solar capture, evaporation and condensation processes. Solar radiation data was captured in several days in Perak, Malaysia. Three kinds of experiments were done by fabricating triangular solar distillation systems. First type was conventional solar still, second type was combined with 50 Watt solar photovoltaic panel and 40 Watt Dc heater, while third type was integrated with 12 Volt Solar battery and 40 Watt Dc heater. The present investigation showed that the productivity of second and third systems were 150% and 480% of the conventional still type, respectively. The finding of this research can be expected to have wide application in water supply particularly in areas where fresh surface water is limited.

Wave Attenuation of Interlocking Concrete Unit - V (ICU-V)

Wave transmission is one of the components resulted from interaction between incident wave and coastal structure. Factors influencing wave transmission include structure height, crest width and wave condition. This paper presents the analysis of wave transmission and dissipation capability of Interlocking Concrete Unit-V (ICU-V) under different wave conditions and structural parameters based on a 2-D physical model testing. The transmitted wave was reduced more than half of the incident wave when the relative crest height is greater than zero. Structural irregularity of ICU-V promotes breaking of wave on the breakwater crest and the sloping surface. The crest is less effective when the submergence depth greater than-0.20 m or the relative freeboard is greater than-0.286. Overall, ICU-V offers good ability for wave dissipation, which leads to promising performance in sheltering coastal area.

Hydraulic investigation of the H-type floating breakwater

Floating breakwaters are commonly used for wave protection of onshore and offshore facilities in the last decade. The majority of the floating breakwaters developed in the past are solid-type structures that have fixed drafts and may be highly reflective to the incoming waves. In this study, the H-type floating breakwater is proposed to serve as a wave attenuator instead of a wave reflector. The buoyancy of the breakwater is controlled by the placement of sandbags in the chamber embedded within the main body of the structure. The study aims to investigate the hydraulic properties of the H-type floating breakwater in random waves via a physical modeling. The hydraulic characteristics of the breakwater are quantified by the reflection and transmission coefficients as well as the energy dissipation coefficient. The experimental results have shown that the H-type floating breakwater is hydraulically efficient and provides high wave attenuation capability when subjected to short-period waves.

Assessing shoreline response to three submerged breakwaters at Kerteh Bay, Terengganu, Malaysia using Landsat imagery

As part of a project to determine the exact structural and environmental parameters governing the mode and magnitude of salient formation behind a submerged breakwater, a remote sensing technique is being adopted to assess the extent of erosion/accretion at Kerteh Bay, T errengganu, Malaysia. Multi-temporal Landsat satellite images of coarse resolution for the years of 1994, 2000, 2006, 2009 and 2012 were acquired for this purpose. The images were subsets divided into smaller areas of interest and classified using supervised classification of support vector machine. The classified image is then vectorized to extract shoreline based on waterline in each of the subset rasters images. Tidal correction were adopted to correct the waterline/shoreline to the mean sea level (MSL) datum. Comparison of corrected shorelines was carried to obtain the extent of erosion/accretion at the Kerteh Bay, Terrenganu, Malaysia. It was observed that substantial accretion was observed between the years 1994-2006 at the upper part of the study area, the part between northern part and the southern part also experienced accretion but not as much as compared to northern part for the same year. Erosion was noted between the years 2006-2012 for all of the areas of the study area but the rate slowed down between the years 2009-2012 for all the areas. Slope estimated from the imageries were compared with in situ slope of the same area, this served as a validation for the method used.

Response of Partially Covered Road Embankments and its Environmental Impact

Tropical regions have always suffered soil loss by water which deteriorates the surrounding environment in several ways. This paper focuses on one of an issue that under the tropical rainfall event how the newly constructed bare highway affects the water turbidity and total suspended solids in a water channel. The study was based on a pilot scale field test which was constructed in compliance with the real field conditions. The study was limited to the tropical rainfall event of 40 mm/hr, native grass cover, sandy loam, and for the road side slope of 1V:1.5H (~ 30°). To determine the turbidity and total suspended solids (TSS), three plots were observed with the different percentage of covers namely, no cover (plot A-control plot), 50% of the grass covered surface (plot B), and 30% of the grass covered surface (plot C). The purpose of the study was to observe the influence of these three plots on the dependent variables that is turbidity and TSS. The study summarizes that the presence of cover is adequate enough to cope with this issue to an extent. The results obtained showed that the bare soil surface performed worst under the rainfall intensity of 40 mm/hr for both the dependent variables. The maximum turbidity values observed from plot B and plot C were 30% and 90.25% respectively of the maximum turbidity value obtained from plot A. Similarly, the maximum TSS values observed from plot B and plot C were 35.21% and 63.76% respectively of the maximum TSS value observed from plot A.

Performance of Mangrove Forests in Coastal Protection

The importance of mangrove forest as a natural protection system has been a focused interest especially after the 2004 tsunami. It was reported that human deaths and property losses were reduced in areas of dense mangrove forests. Devastating incidents in recent years due to extreme environmental and catastrophic conditions that lead to various degrees of damages in the coastal areas have significantly increased awareness on the role of mangrove forests as eco-engineering approach to coastal stability and defense. With the recent urge for mangroves protection and replanting, a sound basis for a more optimum strategy in maintaining mangroves as coastal protection buffer is inevitably required. Hence, this study is aimed to quantify the reduction of wave height by 10 years old mangroves with various densities and tree arrangements. The laboratory experiments were conducted in a narrow wave flume using artificial mangrove models. The results showed that wave height reduction in areas of 100 m width of 10 years old mangroves was 2.5 times more effective as compared to areas without mangroves. Earlier investigation revealed that for areas with 20 years old mangroves was able to dissipate waves four times greater compared to areas without mangroves. For areas with 200 m width of 10 years old mangroves, a density of 0.11 trees/m2 is sufficient to reduce wave height over 77 %. With a difference of less than 3%, the investigation also revealed no significant difference of wave reduction between tandem and staggered arrangements when the mangroves are of 10 years old.

Hydraulic Stability of Interlocking Concrete Unit-V (ICU-V)

Continuous research is conducted to improve the available coastal protection scheme, including to develop an innovative concrete armor unit with interlocking capability. Interlocking Concrete Unit-V (ICU-V) has light weight characteristic and developed specifically for mild wave condition. This paper discusses the performance of ICU-V represented by the Stability coefficient, KD and results of the damage progression investigation under different wave conditions. These were achieved by conducting a 2-D physical model investigation by using JONSWAP random wave spectrum. The damage ratio method was used to assess the damage progression. The optimum KD obtained was 12 with highest damage level of 0.4%, which is comparable with available armor units

The Rain Drop Impact on the Water Discharge and Sediment Transport under the Full-Scale Test

The magnitude of soil erosion by water remains high in the tropical regions. The construction activities further worsen this process which leads to the undesirable effects. The newly constructed highway embankments usually remain bare and are considered to be the prime agent of soil loss. The soil surface with an appropriate cover helps restricting the soil detachment for which many agronomic soil conservation practices have been used. This paper integrates that why a simple grass cover has been recommended to cope with this inevitable issue. It further assimilates the results obtained from a full scale test conducted in the Perak State Malaysia under the simulated rainfall condition of 40 mm/hour (average rainfall event) for which the rainfall data was obtained from the Meteorological department Perak State, Malaysia from the year (2005-2011). The volume rate of water flow and sediment transport was observed at different time intervals for three plots i.e. (Plot-I) the fully grass covered surface, (Plot-II) the bare soil surface, and (Plot-III) 50% of the grass covered surface with an area of 2 meters by 6 meters having a slope angle of 30°. The results obtained showed maximum water discharge and soil loss for (Plot-II) the bare soil surface, which was found to be 5.78 x 10-5 m3 sec-1 and 500.9 g m-2 respectively.

Review of Grass Cover as a Protective Layer Against Surficial Erosion

The undesirable effects on the soil (loss of fertile top soil) have been observed mainly due to erosion by water. The soil surface with an appropriate cover helps improving the soil structure for which many agronomic soil conservation practices have been used. This paper integrates that why a simple grass cover has been recommended to cope with this inevitable issue. The grass structure, influence of the root zone, grass efficiency against runoff and soil loss, and grass application at different slope angles have been studied. This paper further review the different parameters which must be considered while protecting the soil against erosion including hill slope shapes, characteristics of different plant types, proper compaction, soil modification, and cost comparison of different soil protection techniques.

Mitigation of soil erosion using sludge on road embankments — A conceptual study

There is a contradiction regarding the use of sludge as a soil amendment fertilizer. As stated in many studies it has many benefits as well as hazards concerning environmental issues. However, its use on road embankments for the purpose of reducing soil erosion is lightly discussed before and therefore is focused in this paper. Humid tropical regions like Malaysia have always remained the victim of severe erosion, supported by many factors including newly built road embankments which usually remain bare after the road construction. This paper integrates the comparative field analysis regarding the application of sludge on the road embankment within the limitations as it is found numerous in heavy metals. Furthermore, it is rich in nutrients which are considered necessary medium for the vegetation revival and soil formation. However, this paper is supported by an innovation which comes with a concept of applying sludge when properly treated and then implemented to the embankments.