ORCID Profile
0000-0001-7814-3413
Current Organisations
Higher Education Academy
,
University of South Australia
,
Hong Kong Academy of Medicine (Medicine)
,
University of Oxford
,
Hong Kong College of Physicians
,
Hong Kong College of Physicians (Neurology)
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Publications
Monitoring and Source Apportionment for Particulate Matter Pollution in Six Asian Cities ...................................................................... Nguyen Thi Kim Oanh, Prapat Pongkiatkul,
Publisher: CRC Press
Date: 05-07-2012
DOI: 10.1201/B12235-8
Probabilistic total PM2.5 emissions from vehicular sources in Australian perspective
Publisher: Springer Science and Business Media LLC
Date: 15-08-2021
Sustainability Assessment of Using Recycled Aggregates in Concrete Block Pavements
Publisher: MDPI AG
Date: 25-05-2020
DOI: 10.3390/SU12104313
Abstract: The mechanistic design of a concrete block pavement (CBP) can be very complicated and often requires the use of computer programs. This paper presents a new mechanistic-empirical method, which is implemented in a computer program (DesignPave) that calculates base course/sub-base thicknesses for a range of design inputs such as traffic load, interlocking properties, and material stiffness. A range of virgin and recycled unbound granular materials were also experimentally tested to characterize them for possible use as base course or sub-base materials. Combining the new mechanistic-empirical method and the range of base course/sub-base course materials (virgin and recycled aggregates), it was found that while a CBP containing recycled aggregates did not offer a significant direct financial benefit based on the characteristics or material costs, the associated environmental benefits were very high.
Meso-scale on-road vehicle emission inventory approach: a study on Dhaka City of Bangladesh supporting the ‘cause-effect’ analysis of the transport system
Publisher: Springer Science and Business Media LLC
Date: 08-02-2016
DOI: 10.1007/S10661-016-5151-4
Abstract: The study aims to develop an emission inventory (EI) approach and conduct an inventory for vehicular sources in Dhaka City, Bangladesh. A meso-scale modelling approach was adopted for the inventory the factors that influence the emissions and the magnitude of emission variation were identified and reported on, which was an innovative approach to account emissions unlike the conventional inventory approaches. Two techniques for the emission inventory were applied, viz. (i) a combined top-down and bottom-up approach that considered the total vehicle population and the average diurnal on-road vehicle speed profile in the city and (ii) a bottom-up approach that accounted for road link-specific emissions of the city considering diurnal traffic volume and speed profiles of the respective roads. For the bottom-up approach, road link-specific detailed data were obtained through field survey in 2012, where mid-block traffic count of the day, vehicle speed profile, road network and congestion data were collected principally. The emission variances for the change in transport system characteristics (like change in fuel type, AC usage pattern, increased speed and reduced congestion/stopping) were predicted and analysed in this study congestion influenced average speed of the vehicles, and fuel types in the vehicles were identified as the major stressors. The study performance was considered reasonable when comparing with the limited number of similar studies conducted earlier. Given the increasing trend of private vehicles each year coupled with increasing traffic congestion, the city is under threat of increased vehicular emissions unless a good management strategy is implemented. Although the inventory is conducted for Dhaka and the result may be important locally, the approach adopted in this research is innovative in nature to be followed for conducting research on other urban transport systems.
Changes in thornthwaite moisture index and reactive soil movements under current and future climate scenarios—a case study
Publisher: MDPI AG
Date: 17-10-2021
DOI: 10.3390/EN14206760
Abstract: Expansive soils go through significant volume changes due to seasonal moisture variations resulting in ground movements. The ground movement related problems are likely to worsen in the future due to climate change. It is important to understand and incorporate likely future changes in design to ensure the resilience of structures built on such soils. However, there has been a limited amount of work quantifying the effect of climate change on expansive soils movement and related behaviour of structures. The Thornthwaite Moisture Index (TMI) is one of the commonly used climate classifiers in quantifying the effect of atmospheric boundary on soil behaviour. Using the long-term weather data and predicted future changes under different emission scenarios, a series of TMI maps are developed for South Australia. Potential changes in ground movement are then estimated for a selected area using a simplified methodology where the effect of future climate is captured through changes in TMI. Results indicate that South Australia is likely to face a significant reduction in TMI under all emission scenarios considered in this study. The changes in TMI will lead to a considerable increase in potential ground movement which will influence the behaviour of structures built on them and in some areas may lead to premature failure if not considered in the design.
A Review of Current Design and Construction Practice for Road Kerbs and a Sustainability Analysis
Publisher: MDPI AG
Date: 21-01-2022
DOI: 10.3390/SU14031230
Abstract: Kerb is an integral part of road infrastructure and performs several important functions, including providing stability to the edges of the road and providing effective drainage. Their performance can significantly influence the behaviour and service life of a road. The design conditions, construction materials and their sustainability can be important to assess from an asset management and sustainable construction point of view even though this area has been paid limited research attention in the past. This paper reviews the available literature on the design and construction considerations for kerbs and critically analyses them with a special focus on sustainable construction practice. The different materials commonly used around the world for the construction of kerb in terms of their properties, failure and available design guidelines have been discussed along with their management practice. Special situations, such as expansive soil movement and tree root-related problems, have also been considered, and the current guidelines for designing in such situations have also been discussed. A carbon footprint and sustainability analysis has been conducted on the current practice of using natural aggregate concrete and compared against several potential alternatives. The review of the design process indicated that the current practice relies on over-simplified design procedures and identified scopes for improvement, especially with the incorporation of mechanical behaviour of the material being used in construction. The carbon footprint and sustainability analysis indicated that the use of alternative materials could result in significant savings in the kerb construction industry’s carbon footprint.
Spatial Analysis of the Water Harvesting Potential of Permeable Pavements in Australia
Publisher: MDPI AG
Date: 06-12-2022
DOI: 10.3390/SU142316282
Abstract: An increase in impermeable surface areas with urban development contributes to the rapid and large amount of surface runoff during rainfall. This often requires higher capacity stormwater collection systems, which can cause stress on the existing drainage system and this subsequently contributes to urban flooding. However, urban runoff can be reduced and managed for flood control and converted into a useful resource by harvesting and reusing the water. This can be achieved by switching from impermeable to permeable pavements. However, the amount of stormwater that can be harvested in a permeable pavement system depends on many factors, including rainfall, the water reuse demand and the materials used. This research aims to assess the requirements for permeable pavement design across Australia to balance demand, runoff reduction and construction requirements. A design approach employing the hydrological effects of the infiltration system was adopted for the analysis, along with a spatial analysis for a probabilistic prediction. A relationship was also established to predict a probable design thickness of pavement for various parameters. The research showed that in most Australian cities, for a 120 mm permeable pavement thickness, 40–80% of rainfall-runoff could be harvested, meeting about 10–15% of domestic water demand. The approach developed in this study can be useful for screening the potential of permeable pavements for water harvesting and for predicting spatially where a circular economic approach can be more efficient.
Sex Differences in Association Between Gut Microbiome and Essential Hypertension Based on Ambulatory Blood Pressure Monitoring
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2023
DOI: 10.1161/HYPERTENSIONAHA.122.20752
Abstract: Sex differences in the pathogenesis of hypertension exist. While gut microbiota (GM) has been associated with hypertension, it is unclear whether there are sex-linked differences in the association between GM and hypertension. We conducted a cross-sectional study to investigate the sex differences in associations between GM characterized by shotgun sequencing, GM-derived short-chain fatty acids, and 24-hour ambulatory blood pressure in 241 Hong Kong Chinese (113 men and 128 women mean age, 54±6 years). The hypertensive group was associated with GM alterations however, significant differences in β- ersity and GM composition in hypertensive versus normotensive groups were only observed in women and not in men under various statistical models adjusting for the following covariates: age, sex, body mass index, sodium intake estimated by spot urine analysis, blood glucose, triglycerides, low- and high-density lipoprotein cholesterol, smoking, menopause, and fatty liver status. Specifically, Ruminococcus gnavus , Clostridium bolteae , and Bacteroides ovatus were significantly more abundant in the hypertensive women, whereas Dorea formicigenerans was more abundant in the normotensive women. No bacterial species were found to be significantly associated with hypertension in men. Furthermore, total plasma short-chain fatty acids and propionic acid were independent predictors of systolic and diastolic blood pressure in women but not men. GM dysregulation was strongly associated with 24-hour ambulatory blood pressure in women but not men, which may be mediated through propionic acid. Our work suggests that sex differences may be an important consideration while assessing the role of GM in the development and treatment of hypertension.
A call for global action for rare diseases in Africa
Publisher: Springer Science and Business Media LLC
Date: 23-12-2020
Cerebral microbleeds and stroke risk after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies
Publisher: Elsevier BV
Date: 07-2019
State-of-the-art review of microbial-induced calcite precipitation and its sustainability in engineering applications
Publisher: MDPI AG
Date: 04-08-2020
DOI: 10.3390/SU12156281
Abstract: Microbial-induced calcite precipitation (MICP) is a promising new technology in the area of Civil Engineering with potential to become a cost-effective, environmentally friendly and sustainable solution to many problems such as ground improvement, liquefaction remediation, enhancing properties of concrete and so forth. This paper reviews the research and developments over the past 25 years since the first reported application of MICP in 1995. Historical developments in the area, the biological processes involved, the behaviour of improved soils, developments in modelling the behaviour of treated soil and the challenges associated are discussed with a focus on the geotechnical aspects of the problem. The paper also presents an assessment of cost and environmental benefits tied with three application scenarios in pavement construction. It is understood for some applications that at this stage, MICP may not be a cost-effective or even environmentally friendly solution however, following the latest developments, MICP has the potential to become one.
Permeable Pavements for Flood Control in Australia: Spatial Analysis of Pavement Design Considering Rainfall and Soil Data
Publisher: MDPI AG
Date: 21-04-2022
DOI: 10.3390/SU14094970
Abstract: Permeable pavements allow rainfall and surface runoff to infiltrate through their surface, and this reduces urban flooding by increasing water management efficiency. The design of permeable pavements depends heavily on rainfall and soil conditions for a particular area. This study investigates the required base course thickness in different areas across Australia that can effectively reduce flood intensities. A detailed hydraulic analysis was conducted, considering the pavement materials, soil characteristics and rainfall intensities across Australia. The research also developed a relationship between base course thickness, rainfall intensity and soil classification, which can facilitate reasonable predictions of required design thickness for any location. The results showed a strong relationship between soil characteristics and pavement thickness, with clay soils requiring increased pavement thickness correlated with rainfall intensity. A spatial analysis was conducted, producing a tool for initial screening on the design requirements, before proceeding with a detailed design.
Effectiveness of Teaching Research Nexus to Enhance Students' Learnings
Publisher: IEEE
Date: 11-2017
Probabilistic Health Risk Assessment of Vehicular Emissions as an Urban Health Indicator in Dhaka City
Publisher: MDPI AG
Date: 15-11-2019
DOI: 10.3390/SU11226427
Abstract: Emissions modelling is an important tool for assessing the urban health status of any city, but often the assessments are affected by the uncertainty of the data used for the modelling. Therefore, a Monte Carlo simulation technique was used for a probabilistic emissions modelling of Dhaka City by simulating 20,000 scenarios for the highest and lowest values of traffic volume and speed profiles for each of the major road links. Only nitrogen oxide (NOx) emissions from on-road vehicles were considered, as vehicular sources are major contributors. Each dataset included two peak periods and an offpeak period of the day to cover the diurnal variation within each road link. Using the probability of the magnitude of emissions along with the corresponding health risk, a series of spatial urban health risk severity scenarios was generated for 2018 and 2024, suggesting that transportation and environmental planning is required for urban sustainability.
Analysis of transport eco-efficiency scenarios to support sustainability assessment: a study on Dhaka City, Bangladesh
Publisher: Springer Science and Business Media LLC
Date: 07-2017
DOI: 10.1007/S10661-017-6078-0
Abstract: The study focused to assess the level of efficiency (of both emissions and service quality) that can be achieved for the transport system in Dhaka City, Bangladesh. The assessment technique attempted to quantify the extent of eco-efficiency achievable for the system modifications due to planning or strategy. The eco-efficiency analysis was facilitated with a detailed survey data on Dhaka City transport system, which was conducted for 9 months in 2012-2013. Line source modelling (CALINE4) was incorporated to estimate the on-road emission concentration. The eco-efficiency of the transport systems was assessed with the 'multi-criteria analysis' (MCA) technique that enabled the valuation of systems' qualitative and quantitative parameters. As per the analysis, driving indiscipline on road can alone promise about 47% reductions in emissions, which along with the number of private vehicles were the important stressors that restrict achieving eco-efficiency in Dhaka City. Detailed analysis of the transport system together with the potential transport system scenarios can offer a checklist to the policy makers enabling to identify the possible actions needed that can offer greater services to the dwellers against lesser emissions, which in turn can bring sustainability of the system.
Vehicular PM Emissions and Urban Public Health Sustainability: A Probabilistic Analysis for Dhaka City
Publisher: MDPI AG
Date: 04-08-2020
DOI: 10.3390/SU12156284
Abstract: Particulate Matter (PM) pollution is generally considered as a prime indicator of urban air quality and is linked to human health hazards. As vehicles are a vital component of an urban setting, the risks of particulate pollution need to be assessed. An emission modelling is essential for that, and thus stochastic modelling approach involving Monte Carlo simulation technique was applied, aiming to reduce the uncertainty in emission modelling. The risks scenarios for the emissions were generated for 2019 (present state) and 2024 (future), integrating the probability of emissions and the associated AQI (Air Quality Index). Despite the vehicles being a minor source of PM in Dhaka (compared to the contribution from other sources), about one-third of the city is found under high risk due to the exhaust particulate pollution having the potentiality to cover more than 60% of the city in the coming years, affecting the urban public health sustainability. However, the extent of implementation of planning and management strategies can revert the scenarios for the city, which can plausibly reduce the risk from 80% to 50%, or even to a no-risk state.
Assessment of acid deposition over Dhaka division using CAMx–MM5 modeling system
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.5094/APR.2011.052
Related Organisations
Higher Education Academy
Location: United Kingdom of Great Britain and Northern Ireland
University Of Oxford
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
No related grants have been discovered for Asif Iqbal.