Cadmium (Cd) is one of the heavy metals pollutants and its accumulation impacted the sustainabili... more Cadmium (Cd) is one of the heavy metals pollutants and its accumulation impacted the sustainability of marine organisms. The aim of current research was to isolate and identify the cadmium-reducing bacteria from contaminated coastal sediment in Karangsong port, Indramayu, Indonesia. The isolates were investigated for its potential to reduce cadmium showed the cadmium reduction drastically up to 50% at 6 hours treated under different cadmium concentration of 0,5, 1, and 1,5 ppm, respectively. Morphological characteristics were observed in most of isolates. Out of 8 isolates, two selected strains such as Karangsong Cd3 and Cd7 were identified by 16S rRNA sequencing as Pseudoalteromonas issachenkonii strain KMM 3549 (Acc. No. NR 025139.1) and Pseudoalteromonas tetraodonis GFC strain IAM 14160 (Acc. No. NR 041787.1), respectively. The cadmium resistance profile showed that the selected isolates were resistant to various concentration of cadmium (Cd). These results suggest that the Karan...
The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Sal... more The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Salinity intrusion was simulated in the study area by 1D numerical model. A 1-D hydrodynamic model coupled with a salinity model was used to analyze the salinity intrusion within Chukai River after the implementation of the flood mitigation project. The model was calibrated and validated using the data measured in Chukai River at 3 points from January 2007 until August 2013. Water quality simulation of salinity has been carried out once an excellent hydrodynamic model was established. The simulated river flow was reasonably matched to the measured data with R2 value 0.88, 0.92 and 0.82, respectively. Results suggest that after the realignment of Chukai River, the seawater intrudes further to the upstream river, causing the increasing salinity in the river about 10 - 15 ppt. However, with the floodway development, the channel would allow more water from Kemaman River being discharged into Ch...
The increasing demands in textile industries has created huge production of textile coloured prod... more The increasing demands in textile industries has created huge production of textile coloured products globally, leading to large production of textile effluent. Textile effluent is often discharged to the environment without proper treatment by the textile factories. The untreated textile effluent typically contains harmful chemicals and is hazardous to the environment, due to the toxicity of the dyes used. In this study, biological treatment is applied to the textile effluent. A 2-level full factorial design from response surface methodology (RSM) was applied to find the optimized treatment process condition for the textile wastewater degradation. Sixteen runs of experiment with 4 factors were performed; bacterial inoculum (%, v/v), temperature (℃), agitation (rpm), and pH were tested. It was observed highest decolourization obtained (91.95 % with pH 4, low concentration of bacterial inoculum (5 %), agitation speed (200 rpm) and temperature (40 ℃)) meanwhile lowest decolourization ...
Network Modeling Analysis in Health Informatics and Bioinformatics
COVID-19 has triggered a global health crisis. Death from severe respiratory failure and symptoms... more COVID-19 has triggered a global health crisis. Death from severe respiratory failure and symptoms, including fever, dry cough, sore throat, anosmia, and gastrointestinal disturbances, has been attributed to the disease. Development of screening and diagnosis methods prove to be challenging due to shared clinical features between COVID-19 and other pathologies, such as Middle Eastern respiratory syndrome, severe acute respiratory syndrome, and common colds. This study aims to develop a comprehensive one-stop online public health screening system based on clinical and epidemiological criteria. The immediate target populations are the university students and staff of University Sultan Zainal Abidin and the civil servants of the Malaysian Ministry of Science, Technology, and Innovation. Forty-nine (49) clinical and epidemiological factors associated with COVID-19 were identified and prioritized based on their prevalence via rigorous review of the literature and vetting sessions. A pilot study of 200 volunteers was conducted to assess the extent of risk mitigation of COVID-19 infection among the university students and civil servants using the prototyped model. Consequently, twelve (12) clinical parameters were identified and validated by the medical experts as essential variables for COVID-19 risk-screening. The updated model was then revalidated via real mass-screening of 5000 resulting in the final adopted CHaSe system. Principal component analysis (PCA) was used to confirm the weightage of risk level toward COVID-19 to procures the optimal accuracy, reliability, and efficiency of this system. Twelve (12) factor loadings accountable for 58.287% of the clinical symptoms and clinical history variables with forty-nine (49) parameters of COVID-19 were identified through PCA. The variables of the clinical and epidemiological aspects identified are the C6 (History of joining high-risk gathering (where confirmed cases had been recorded), CH11 [History of contact with confirmed cases (close contact)], CH13 [Duration of exposure with confirmed cases (minutes)] with substantial positive factors of 0.7053, 0.706 and 0.5086, respectively. The contribution toward high-risk infection of COVID-19 was firmly attributable to the variables CH14 [Last contact with confirmed cases (days)], CH13 [Duration of exposure with confirmed cases (minutes)], and S1 (Age). The revalidated PCA for 5000 respondents also yielded twelve significant PCs with a cumulative variance of 58.288%. Importantly, the medical experts have revalidated the CHaSe system for accuracy of all clinical aspects (clinical symptoms and clinical history) and epidemiological links to COVID-19 infection. After revalidating the model for 5000 respondents, the PC variance for PC1, PC2, PC3, and PC4 was 27.36%, 11.79%, 10.347%, and 8.785%, respectively, with the cumulative explanation of 58.288% in data variability. The level of risks detected using the CHaSe system toward COVID-19 provides optimal accuracy, reliability, and efficiency to conduct mass-screening of students and government servants for COVID-19 infection.
Global Positioning System (GPS) was conceived in the early 70s by the US military for positioning... more Global Positioning System (GPS) was conceived in the early 70s by the US military for positioning and timing purposesand achieved its Full Operational Capacity (FOC) in July ‘95. Even long before its FOC it had shown positioningaccuracy far better than the other positioning tools available; so superior was GPS that they may face redundancy. Theavailability of GPS to all users however meant it was available to the parties, adversarial to the US government. Realisingthat GPS may be used for hostile activities (against the US and her allies), a concept of ‘Accuracy Denial’ was evolved inJune 1983, which was later known as ‘Selective Availability’ (SA) and officially implemented in March 1990. SA is amechanism whereby any unauthorised GPS user will be deprived of GPS true (accuracy) potential in real time usage.Under SA the positioning accuracy for the unauthorised users was reduced by more than 100% and the cost for GPScivilian uses also increased substantially since GPS had to be oper...
International Journal of Engineering & Technology, 2018
The study on Watershed Sustainability Index (WSI) has been conducted to analyst the environmental... more The study on Watershed Sustainability Index (WSI) has been conducted to analyst the environmental condition in the area incorporating ecological baseline and socio-economic conditions. WSI is an integrated indicator based on basin Hydrology, Environment, Life and Policy (HELP) state condition. It is suitable to be applied in the Langat River Basin in Malaysia which has similar catchment area (up to 2,350 km2) and is one of the UNESCO HELP River Basin since 2004. The WSI analysis which uses a pressure–state–response function based on basin HELP Indicator was done for Langat River Basin by using relevant available 5 years data for the period of 2009 to 2013. It is found that Langat River Basin is having WSI value of 0.68 which falls under the category of medium sustainability (between 0.5-0.8). Based on the maximum value (i.e. 1) or high sustainability (i.e. WSI value more than 0.8) it can be said that Langat is in the good side in term of sustainability. Few management aspects need t...
International Journal of Engineering & Technology, 2018
Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone ... more Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone and secondary organic aerosol. Most tropical countries such as Malaysia, Singapore, Indonesia, Brunei experience high ozone pollution. Beside ozone, oxides of nitrogen (NOx) from vehicular emissions also play an important role in photochemical pollution. NOx, particularly nitric oxide (NO), helps to ‘clean up’ ozone concentrations close to traffic in the ambient air of urban areas. Thus, knowledge of the chemistry of ozone-VOCs-NOx and finding the sources of VOCs are crucial to proceed with an appropriate mitigation strategy. Thus, the detection of ozone precursors and related VOCs is thoroughly discussed. This review finds that the inertness, hydrophobicity, and the effect of the artefact materials are very significant factors to be explored in the selection of the sorbent materials. In the SEA region, relative humidity is relatively high and exceeds 90% during the northeast monsoon. Th...
This study aims to identify the degree of which factors contribute to the rainwater quality and u... more This study aims to identify the degree of which factors contribute to the rainwater quality and understanding anthropogenic contributions to the atmospheric environment. A total of 1830 rainwater data were collected from rain gauge stations distributed all over the country. Factor analysis were applied to the studied variables to evaluate the physicochemical composition of rainwater samples in Malaysia. The results showed that the extracted four components accounted for 43.45% of the total variance. The source of ionic components was found to be mainly originated from sea salt ions, while biomass burning indicated it was the primary source of anthropogenic activities in the study area. Low heavy metal concentration were detected in the rainwater samples. Generally, the rainwater in the study area was of good rainwater quality and less affected by anthropogenic activities. Some variables were identified to influence the variability of rain, hence affecting the variability of rainwater in the study area, including magnesium, sodium, chloride, ammonium, potassium, nitrate, sulphate, nickel, formate and iron. The variability of these components caused in acidity and conductivity in rainwater samples. This study provides a basis for the rational utilisation of rainwater for peoples' lives, thus maintaining the sustainability of water resources in the environment. Additional research is needed to identify the index of rainwater quality and determine the uses for each index level.
The hydrology hydraulic model is established to assess environmental information on hydrology whi... more The hydrology hydraulic model is established to assess environmental information on hydrology which can be used to investigate causes of various environmental problems at the river and natural lake catchment. This study reports on sediment concentrations at a river using a gravimetric method to investigate the hydrology system at a lake catchment. The measurement was carried out at the upstream, midstream, and downstream stations on the river in normal, rainy and post-rainy seasons. The stations are located along the Chini River, which are connected to a catchment lake (located at latitude 3°26’36.41”E-3°27’03.26”E and longitude 102°54’31.94”N-102°53’35.49”N). From the measurements, it is estimated that on average 787.621 tonne/km 2 of sediment is transferred into the natural lake via Chini River annually. The correlation of statistical analysis between the sediment load and discharge study was very significant (R 2 = 0.980). There is a linear relation between the area of the catchm...
Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting ma... more Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting marine life. The EU's Marine Strategy Framework Directive (MSFD) includes a specific indicator focused on this noise. This indicator is the yearly average sound level in third-octave bands with centre frequencies at 63 Hz and 125 Hz. These levels are described for Falmouth Bay, UK, an active port at the entrance to the English Channel. Underwater sound was recorded for 30 min h −1 over the period June 2012 to November 2013 for a total of 435 days. Mean third-octave levels were louder in the 125-Hz band (annual mean level of 96.0 dB re 1 μPa) than in the 63-Hz band (92.6 dB re 1 μPa). These levels and variations are assessed as a function of seasons, shipping activity and wave height, providing comparison points for future monitoring activities, including the MSFD and emerging international regulation.
Sewage contamination is a principal concern in water quality management as pathogens in sewage ca... more Sewage contamination is a principal concern in water quality management as pathogens in sewage can cause diseases and lead to detrimental health effects in humans. This study examines the distribution of seven sterol compounds, namely coprostanol, epi-coprostanol, cholesterol, cholestanol, stigmasterol, campesterol, and β-sitosterol in filtered and particulate phases of sewage treatment plants (STPs), groundwater, and river water. For filtered samples, solid-phase extraction (SPE) was employed while for particulate samples were sonicated. Quantification was done by using gas chromatography-mass spectrometer (GC-MS). Faecal stanols (coprostanol and epi-coprostanol) and β-sitosterol were dominant in most STP samples. Groundwater samples were influenced by natural/biogenic sterol, while river water samples were characterized by a mixture of sources. Factor loadings from principal component analysis (PCA) defined fresh input of biogenic sterol and vascular plants (positive varimax factor (VF)1), aged/treated sewage sources (negative VF1), fresh- and less-treated sewage and domestic sources (positive VF2), biological sewage effluents (negative VF2), and fresh-treated sewage sources (VF3) in the samples. Association of VF loadings and factor score values illustrated the correlation of STP effluents and the input of biogenic and plant sterol sources in river and groundwater samples of Linggi. This study focuses on sterol distribution and its potential sources; these findings will aid in sewage assessment in the aquatic environment.
As part of the implementation of a rainwater harvesting system as an alternative water source sup... more As part of the implementation of a rainwater harvesting system as an alternative water source supply for non-potable use, therefore the characteristic of chemical compounds was significantly explored. The Department of Chemistry, Malaysia, gave the data set for three years (2017-2019). Some chemometric techniques, including PCA, were performed to identify the dimensionality of the rainwater data, hence establishing the rainfall index's purity to determine the quality of rainwater in the study area. Discriminant analysis managed to differentiate each rain gauge station. Cluster analysis was then applied to perform smaller group of rain gauge stations. The result demonstrates that sea salt, secondary aerosols, trace metals, crustal origin, and organic acid dominated the dimensionality of rainwater data with a total variance of 53.38% and indicated that the PRI was significantly diversified into good purity of rainfall index (GPRI), (Labuan and Danum Valley), moderate purity of rai...
Methods : Central composite design (CCD) from response surface methodology (RSM) was applied in o... more Methods : Central composite design (CCD) from response surface methodology (RSM) was applied in order to achieve the optimized treatment process condition for the textile dyes wastewater degradation. Two-level of three process parameters with six center points resulted a total of twenty runs of experiments were performed. Bacterial inoculum (-1,+1) (%, v/v), agitation (-1, +1) (rpm), and pH (-1, +1) were tested.
The main focus of this study is exploring the spatial distribution of polyaromatics hydrocarbon l... more The main focus of this study is exploring the spatial distribution of polyaromatics hydrocarbon links between oil spills in the environment via Support Vector Machines based on Kernel-Radial Basis Function (RBF) approach for high precision classification of oil spill type from its sample fingerprinting in Peninsular Malaysia. The results show the highest concentrations of Σ Alkylated PAHs and Σ EPA PAHs in ΣTAH concentration in diesel from the oil samples PP3_liquid and GP6_Jetty achieving 100% classification output, corresponding to coherent decision boundary and projective subspace estimation. The high dimensional nature of this approach has led to the existence of a perfect separability of the oil type classification from four clustered oil type components; i.e diesel, bunker C, Mixture Oil (MO), lube oil and Waste Oil (WO) with the slack variables of ξ ≠ 0. Of the four clusters, only the SVs of two are correctly predicted, namely diesel and MO. The kernel-RBF approach provides e...
International Journal of Environmental Analytical Chemistry, 2021
Textile industry has been rapidly progressing over the years, leading to an increasing volume of ... more Textile industry has been rapidly progressing over the years, leading to an increasing volume of water usage that contributes to the large production of textile wastewater. Biological treatment pro...
Rainwater harvesting is an effective alternative practice, particularly within urban regions, dur... more Rainwater harvesting is an effective alternative practice, particularly within urban regions, during periods of water scarcity and dry weather. The collected water is mostly utilized for non-potable household purposes and irrigation. However, due to the increase in atmospheric pollutants, the quality of rainwater has gradually decreased. This atmospheric pollution can damage the climate, natural resources, biodiversity, and human health. In this study, the characteristics and physicochemical properties of rainfall were assessed using a qualitative approach. The three-year (2017–2019) data on rainfall in Peninsular Malaysia were analysed via multivariate techniques. The physicochemical properties of the rainfall yielded six significant factors, which encompassed 61.39% of the total variance as a result of industrialization, agriculture, transportation, and marine factors. The purity of rainfall index (PRI) was developed based on subjective factor scores of the six factors within thre...
Sewage contamination is a principal concern in water quality management as pathogens in sewage ca... more Sewage contamination is a principal concern in water quality management as pathogens in sewage can cause diseases and lead to detrimental health effects in humans. This study examines the distribution of seven sterol compounds, namely coprostanol, epi-coprostanol, cholesterol, cholestanol, stigmasterol, campesterol, and β-sitosterol in filtered and particulate phases of sewage treatment plants (STPs), groundwater, and river water. For filtered samples, solid-phase extraction (SPE) was employed while for particulate samples were sonicated. Quantification was done by using gas chromatography-mass spectrometer (GC-MS). Faecal stanols (coprostanol and epi-coprostanol) and β-sitosterol were dominant in most STP samples. Groundwater samples were influenced by natural/biogenic sterol, while river water samples were characterized by a mixture of sources. Factor loadings from principal component analysis (PCA) defined fresh input of biogenic sterol and vascular plants (positive varimax facto...
Reservoirs play a strategic role in the context of sustainable energy supply. Unfortunately, the ... more Reservoirs play a strategic role in the context of sustainable energy supply. Unfortunately, the majority of the reservoirs are facing water-quality degradation due to complex pollutants originating from activities both in the catchment and inside the reservoir. This research was aimed at assessing the extent of the water degradation, in terms of corrosivity level, and at examining its impacts on hydropower capacity and operation. Water quality data (total dissolved solids, pH, calcium, bicarbonate, and temperature) were obtained from 20 sampling stations in the Cirata Reservoir from 2007 to 2016. The results show that the river water is already corrosive (Langelier Saturation Index, LSI = − 0.21 to − 1.08), and, the corrosiveness becoming greater when entering the reservoir (LSI = − 0.52 to − 1.49). The water corrosivity has caused damage to the hydro-mechanical equipment and lowering production capacity. The external environment of the catchment hosts complex human activities, suc...
Cadmium (Cd) is one of the heavy metals pollutants and its accumulation impacted the sustainabili... more Cadmium (Cd) is one of the heavy metals pollutants and its accumulation impacted the sustainability of marine organisms. The aim of current research was to isolate and identify the cadmium-reducing bacteria from contaminated coastal sediment in Karangsong port, Indramayu, Indonesia. The isolates were investigated for its potential to reduce cadmium showed the cadmium reduction drastically up to 50% at 6 hours treated under different cadmium concentration of 0,5, 1, and 1,5 ppm, respectively. Morphological characteristics were observed in most of isolates. Out of 8 isolates, two selected strains such as Karangsong Cd3 and Cd7 were identified by 16S rRNA sequencing as Pseudoalteromonas issachenkonii strain KMM 3549 (Acc. No. NR 025139.1) and Pseudoalteromonas tetraodonis GFC strain IAM 14160 (Acc. No. NR 041787.1), respectively. The cadmium resistance profile showed that the selected isolates were resistant to various concentration of cadmium (Cd). These results suggest that the Karan...
The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Sal... more The impact of flood mitigation project in the Kemaman River Basin was assessed in this study. Salinity intrusion was simulated in the study area by 1D numerical model. A 1-D hydrodynamic model coupled with a salinity model was used to analyze the salinity intrusion within Chukai River after the implementation of the flood mitigation project. The model was calibrated and validated using the data measured in Chukai River at 3 points from January 2007 until August 2013. Water quality simulation of salinity has been carried out once an excellent hydrodynamic model was established. The simulated river flow was reasonably matched to the measured data with R2 value 0.88, 0.92 and 0.82, respectively. Results suggest that after the realignment of Chukai River, the seawater intrudes further to the upstream river, causing the increasing salinity in the river about 10 - 15 ppt. However, with the floodway development, the channel would allow more water from Kemaman River being discharged into Ch...
The increasing demands in textile industries has created huge production of textile coloured prod... more The increasing demands in textile industries has created huge production of textile coloured products globally, leading to large production of textile effluent. Textile effluent is often discharged to the environment without proper treatment by the textile factories. The untreated textile effluent typically contains harmful chemicals and is hazardous to the environment, due to the toxicity of the dyes used. In this study, biological treatment is applied to the textile effluent. A 2-level full factorial design from response surface methodology (RSM) was applied to find the optimized treatment process condition for the textile wastewater degradation. Sixteen runs of experiment with 4 factors were performed; bacterial inoculum (%, v/v), temperature (℃), agitation (rpm), and pH were tested. It was observed highest decolourization obtained (91.95 % with pH 4, low concentration of bacterial inoculum (5 %), agitation speed (200 rpm) and temperature (40 ℃)) meanwhile lowest decolourization ...
Network Modeling Analysis in Health Informatics and Bioinformatics
COVID-19 has triggered a global health crisis. Death from severe respiratory failure and symptoms... more COVID-19 has triggered a global health crisis. Death from severe respiratory failure and symptoms, including fever, dry cough, sore throat, anosmia, and gastrointestinal disturbances, has been attributed to the disease. Development of screening and diagnosis methods prove to be challenging due to shared clinical features between COVID-19 and other pathologies, such as Middle Eastern respiratory syndrome, severe acute respiratory syndrome, and common colds. This study aims to develop a comprehensive one-stop online public health screening system based on clinical and epidemiological criteria. The immediate target populations are the university students and staff of University Sultan Zainal Abidin and the civil servants of the Malaysian Ministry of Science, Technology, and Innovation. Forty-nine (49) clinical and epidemiological factors associated with COVID-19 were identified and prioritized based on their prevalence via rigorous review of the literature and vetting sessions. A pilot study of 200 volunteers was conducted to assess the extent of risk mitigation of COVID-19 infection among the university students and civil servants using the prototyped model. Consequently, twelve (12) clinical parameters were identified and validated by the medical experts as essential variables for COVID-19 risk-screening. The updated model was then revalidated via real mass-screening of 5000 resulting in the final adopted CHaSe system. Principal component analysis (PCA) was used to confirm the weightage of risk level toward COVID-19 to procures the optimal accuracy, reliability, and efficiency of this system. Twelve (12) factor loadings accountable for 58.287% of the clinical symptoms and clinical history variables with forty-nine (49) parameters of COVID-19 were identified through PCA. The variables of the clinical and epidemiological aspects identified are the C6 (History of joining high-risk gathering (where confirmed cases had been recorded), CH11 [History of contact with confirmed cases (close contact)], CH13 [Duration of exposure with confirmed cases (minutes)] with substantial positive factors of 0.7053, 0.706 and 0.5086, respectively. The contribution toward high-risk infection of COVID-19 was firmly attributable to the variables CH14 [Last contact with confirmed cases (days)], CH13 [Duration of exposure with confirmed cases (minutes)], and S1 (Age). The revalidated PCA for 5000 respondents also yielded twelve significant PCs with a cumulative variance of 58.288%. Importantly, the medical experts have revalidated the CHaSe system for accuracy of all clinical aspects (clinical symptoms and clinical history) and epidemiological links to COVID-19 infection. After revalidating the model for 5000 respondents, the PC variance for PC1, PC2, PC3, and PC4 was 27.36%, 11.79%, 10.347%, and 8.785%, respectively, with the cumulative explanation of 58.288% in data variability. The level of risks detected using the CHaSe system toward COVID-19 provides optimal accuracy, reliability, and efficiency to conduct mass-screening of students and government servants for COVID-19 infection.
Global Positioning System (GPS) was conceived in the early 70s by the US military for positioning... more Global Positioning System (GPS) was conceived in the early 70s by the US military for positioning and timing purposesand achieved its Full Operational Capacity (FOC) in July ‘95. Even long before its FOC it had shown positioningaccuracy far better than the other positioning tools available; so superior was GPS that they may face redundancy. Theavailability of GPS to all users however meant it was available to the parties, adversarial to the US government. Realisingthat GPS may be used for hostile activities (against the US and her allies), a concept of ‘Accuracy Denial’ was evolved inJune 1983, which was later known as ‘Selective Availability’ (SA) and officially implemented in March 1990. SA is amechanism whereby any unauthorised GPS user will be deprived of GPS true (accuracy) potential in real time usage.Under SA the positioning accuracy for the unauthorised users was reduced by more than 100% and the cost for GPScivilian uses also increased substantially since GPS had to be oper...
International Journal of Engineering & Technology, 2018
The study on Watershed Sustainability Index (WSI) has been conducted to analyst the environmental... more The study on Watershed Sustainability Index (WSI) has been conducted to analyst the environmental condition in the area incorporating ecological baseline and socio-economic conditions. WSI is an integrated indicator based on basin Hydrology, Environment, Life and Policy (HELP) state condition. It is suitable to be applied in the Langat River Basin in Malaysia which has similar catchment area (up to 2,350 km2) and is one of the UNESCO HELP River Basin since 2004. The WSI analysis which uses a pressure–state–response function based on basin HELP Indicator was done for Langat River Basin by using relevant available 5 years data for the period of 2009 to 2013. It is found that Langat River Basin is having WSI value of 0.68 which falls under the category of medium sustainability (between 0.5-0.8). Based on the maximum value (i.e. 1) or high sustainability (i.e. WSI value more than 0.8) it can be said that Langat is in the good side in term of sustainability. Few management aspects need t...
International Journal of Engineering & Technology, 2018
Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone ... more Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone and secondary organic aerosol. Most tropical countries such as Malaysia, Singapore, Indonesia, Brunei experience high ozone pollution. Beside ozone, oxides of nitrogen (NOx) from vehicular emissions also play an important role in photochemical pollution. NOx, particularly nitric oxide (NO), helps to ‘clean up’ ozone concentrations close to traffic in the ambient air of urban areas. Thus, knowledge of the chemistry of ozone-VOCs-NOx and finding the sources of VOCs are crucial to proceed with an appropriate mitigation strategy. Thus, the detection of ozone precursors and related VOCs is thoroughly discussed. This review finds that the inertness, hydrophobicity, and the effect of the artefact materials are very significant factors to be explored in the selection of the sorbent materials. In the SEA region, relative humidity is relatively high and exceeds 90% during the northeast monsoon. Th...
This study aims to identify the degree of which factors contribute to the rainwater quality and u... more This study aims to identify the degree of which factors contribute to the rainwater quality and understanding anthropogenic contributions to the atmospheric environment. A total of 1830 rainwater data were collected from rain gauge stations distributed all over the country. Factor analysis were applied to the studied variables to evaluate the physicochemical composition of rainwater samples in Malaysia. The results showed that the extracted four components accounted for 43.45% of the total variance. The source of ionic components was found to be mainly originated from sea salt ions, while biomass burning indicated it was the primary source of anthropogenic activities in the study area. Low heavy metal concentration were detected in the rainwater samples. Generally, the rainwater in the study area was of good rainwater quality and less affected by anthropogenic activities. Some variables were identified to influence the variability of rain, hence affecting the variability of rainwater in the study area, including magnesium, sodium, chloride, ammonium, potassium, nitrate, sulphate, nickel, formate and iron. The variability of these components caused in acidity and conductivity in rainwater samples. This study provides a basis for the rational utilisation of rainwater for peoples' lives, thus maintaining the sustainability of water resources in the environment. Additional research is needed to identify the index of rainwater quality and determine the uses for each index level.
The hydrology hydraulic model is established to assess environmental information on hydrology whi... more The hydrology hydraulic model is established to assess environmental information on hydrology which can be used to investigate causes of various environmental problems at the river and natural lake catchment. This study reports on sediment concentrations at a river using a gravimetric method to investigate the hydrology system at a lake catchment. The measurement was carried out at the upstream, midstream, and downstream stations on the river in normal, rainy and post-rainy seasons. The stations are located along the Chini River, which are connected to a catchment lake (located at latitude 3°26’36.41”E-3°27’03.26”E and longitude 102°54’31.94”N-102°53’35.49”N). From the measurements, it is estimated that on average 787.621 tonne/km 2 of sediment is transferred into the natural lake via Chini River annually. The correlation of statistical analysis between the sediment load and discharge study was very significant (R 2 = 0.980). There is a linear relation between the area of the catchm...
Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting ma... more Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting marine life. The EU's Marine Strategy Framework Directive (MSFD) includes a specific indicator focused on this noise. This indicator is the yearly average sound level in third-octave bands with centre frequencies at 63 Hz and 125 Hz. These levels are described for Falmouth Bay, UK, an active port at the entrance to the English Channel. Underwater sound was recorded for 30 min h −1 over the period June 2012 to November 2013 for a total of 435 days. Mean third-octave levels were louder in the 125-Hz band (annual mean level of 96.0 dB re 1 μPa) than in the 63-Hz band (92.6 dB re 1 μPa). These levels and variations are assessed as a function of seasons, shipping activity and wave height, providing comparison points for future monitoring activities, including the MSFD and emerging international regulation.
Sewage contamination is a principal concern in water quality management as pathogens in sewage ca... more Sewage contamination is a principal concern in water quality management as pathogens in sewage can cause diseases and lead to detrimental health effects in humans. This study examines the distribution of seven sterol compounds, namely coprostanol, epi-coprostanol, cholesterol, cholestanol, stigmasterol, campesterol, and β-sitosterol in filtered and particulate phases of sewage treatment plants (STPs), groundwater, and river water. For filtered samples, solid-phase extraction (SPE) was employed while for particulate samples were sonicated. Quantification was done by using gas chromatography-mass spectrometer (GC-MS). Faecal stanols (coprostanol and epi-coprostanol) and β-sitosterol were dominant in most STP samples. Groundwater samples were influenced by natural/biogenic sterol, while river water samples were characterized by a mixture of sources. Factor loadings from principal component analysis (PCA) defined fresh input of biogenic sterol and vascular plants (positive varimax factor (VF)1), aged/treated sewage sources (negative VF1), fresh- and less-treated sewage and domestic sources (positive VF2), biological sewage effluents (negative VF2), and fresh-treated sewage sources (VF3) in the samples. Association of VF loadings and factor score values illustrated the correlation of STP effluents and the input of biogenic and plant sterol sources in river and groundwater samples of Linggi. This study focuses on sterol distribution and its potential sources; these findings will aid in sewage assessment in the aquatic environment.
As part of the implementation of a rainwater harvesting system as an alternative water source sup... more As part of the implementation of a rainwater harvesting system as an alternative water source supply for non-potable use, therefore the characteristic of chemical compounds was significantly explored. The Department of Chemistry, Malaysia, gave the data set for three years (2017-2019). Some chemometric techniques, including PCA, were performed to identify the dimensionality of the rainwater data, hence establishing the rainfall index's purity to determine the quality of rainwater in the study area. Discriminant analysis managed to differentiate each rain gauge station. Cluster analysis was then applied to perform smaller group of rain gauge stations. The result demonstrates that sea salt, secondary aerosols, trace metals, crustal origin, and organic acid dominated the dimensionality of rainwater data with a total variance of 53.38% and indicated that the PRI was significantly diversified into good purity of rainfall index (GPRI), (Labuan and Danum Valley), moderate purity of rai...
Methods : Central composite design (CCD) from response surface methodology (RSM) was applied in o... more Methods : Central composite design (CCD) from response surface methodology (RSM) was applied in order to achieve the optimized treatment process condition for the textile dyes wastewater degradation. Two-level of three process parameters with six center points resulted a total of twenty runs of experiments were performed. Bacterial inoculum (-1,+1) (%, v/v), agitation (-1, +1) (rpm), and pH (-1, +1) were tested.
The main focus of this study is exploring the spatial distribution of polyaromatics hydrocarbon l... more The main focus of this study is exploring the spatial distribution of polyaromatics hydrocarbon links between oil spills in the environment via Support Vector Machines based on Kernel-Radial Basis Function (RBF) approach for high precision classification of oil spill type from its sample fingerprinting in Peninsular Malaysia. The results show the highest concentrations of Σ Alkylated PAHs and Σ EPA PAHs in ΣTAH concentration in diesel from the oil samples PP3_liquid and GP6_Jetty achieving 100% classification output, corresponding to coherent decision boundary and projective subspace estimation. The high dimensional nature of this approach has led to the existence of a perfect separability of the oil type classification from four clustered oil type components; i.e diesel, bunker C, Mixture Oil (MO), lube oil and Waste Oil (WO) with the slack variables of ξ ≠ 0. Of the four clusters, only the SVs of two are correctly predicted, namely diesel and MO. The kernel-RBF approach provides e...
International Journal of Environmental Analytical Chemistry, 2021
Textile industry has been rapidly progressing over the years, leading to an increasing volume of ... more Textile industry has been rapidly progressing over the years, leading to an increasing volume of water usage that contributes to the large production of textile wastewater. Biological treatment pro...
Rainwater harvesting is an effective alternative practice, particularly within urban regions, dur... more Rainwater harvesting is an effective alternative practice, particularly within urban regions, during periods of water scarcity and dry weather. The collected water is mostly utilized for non-potable household purposes and irrigation. However, due to the increase in atmospheric pollutants, the quality of rainwater has gradually decreased. This atmospheric pollution can damage the climate, natural resources, biodiversity, and human health. In this study, the characteristics and physicochemical properties of rainfall were assessed using a qualitative approach. The three-year (2017–2019) data on rainfall in Peninsular Malaysia were analysed via multivariate techniques. The physicochemical properties of the rainfall yielded six significant factors, which encompassed 61.39% of the total variance as a result of industrialization, agriculture, transportation, and marine factors. The purity of rainfall index (PRI) was developed based on subjective factor scores of the six factors within thre...
Sewage contamination is a principal concern in water quality management as pathogens in sewage ca... more Sewage contamination is a principal concern in water quality management as pathogens in sewage can cause diseases and lead to detrimental health effects in humans. This study examines the distribution of seven sterol compounds, namely coprostanol, epi-coprostanol, cholesterol, cholestanol, stigmasterol, campesterol, and β-sitosterol in filtered and particulate phases of sewage treatment plants (STPs), groundwater, and river water. For filtered samples, solid-phase extraction (SPE) was employed while for particulate samples were sonicated. Quantification was done by using gas chromatography-mass spectrometer (GC-MS). Faecal stanols (coprostanol and epi-coprostanol) and β-sitosterol were dominant in most STP samples. Groundwater samples were influenced by natural/biogenic sterol, while river water samples were characterized by a mixture of sources. Factor loadings from principal component analysis (PCA) defined fresh input of biogenic sterol and vascular plants (positive varimax facto...
Reservoirs play a strategic role in the context of sustainable energy supply. Unfortunately, the ... more Reservoirs play a strategic role in the context of sustainable energy supply. Unfortunately, the majority of the reservoirs are facing water-quality degradation due to complex pollutants originating from activities both in the catchment and inside the reservoir. This research was aimed at assessing the extent of the water degradation, in terms of corrosivity level, and at examining its impacts on hydropower capacity and operation. Water quality data (total dissolved solids, pH, calcium, bicarbonate, and temperature) were obtained from 20 sampling stations in the Cirata Reservoir from 2007 to 2016. The results show that the river water is already corrosive (Langelier Saturation Index, LSI = − 0.21 to − 1.08), and, the corrosiveness becoming greater when entering the reservoir (LSI = − 0.52 to − 1.49). The water corrosivity has caused damage to the hydro-mechanical equipment and lowering production capacity. The external environment of the catchment hosts complex human activities, suc...
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Papers by Azimah Ismail