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Optimal distribution of best management practices (BMPS) for urban stormwater runoff quantity and quality control / Abdul Razaq Rezaei
Get PDFThe vast development of urban areas throughout the world has substantially impacted the natural landscapes, leading to more imperviousness. Urbanization typically results in a larger amount of runoff volume, increase in flow frequency, duration and peak runoff, faster time of concentration as well as lower infiltration which will affect groundwater recharge. The stormwater runoff quality is also adversely affected in urban areas due to the pollutant loads in stormwater runoff. Best Management Practices (BMPs) and Low Impact Development (LID) have been widely applied to urban impervious surfaces to reduce urban stormwater runoff and improve water quality. In order to achieve the maximum runoff and pollutant concentration reduction with the lowest cost, it is vital to find the optimal number and combination of LID controls implemented on impervious surfaces. In this study, a simulation-optimization model was developed by linking the US Environmental Protection Agency Stormwater Management Model (US EPA SWMM) to coupled model is able to carry out multi-objective optimization and find potential solutions to the optimization objectives by using the SWMM simulation model outputs. The SWMM model was developed by calibrating and validating the model using real quantity and quality data from BUNUS catchment in Kuala Lumpur, Malaysia. The rainfall-flow data and quality data were collected through sampling rainfall events and the Malaysian Department of Irrigation and Drainage (DID). The Total Suspended Solids (TSS) and Total Nitrogen (TN) were selected as pollutants to be used in the simulation model. The LID controls were designed using the catchment characteristics, applied to the model and the performance of the simulation model was tested with real rainfall-flow data from the catchment. The target objectives were to investigate the hydrological performance of LIDs at the catchment scale, to minimize the peak runoff, TSS and TN with the minimum number of LID controls applied, and to minimize the vulnerability of urban areas against flood. This study applied vegetated swale and rain garden to assess the model performance at a catchment scale. The selected LIDs occupied 7% of each sub catchment (of which 40% was swale and 30% was rain garden, respectively). The stormwater runoff substantially reduced, and the runoff quality was also greatly improved by applying the LIDs into the simulation model. The LID removal efficiency was up to 40.42% for TN and 61.60% for TSS, respectively. The peak runoff reduction was also up to 27.44%. The outputs of the simulation model were, then, optimized with the MOPSO model to identify the final best LID types and combination to achieve the maximum peak runoff and pollutant concentration reductions with the minimum number of LIDs. Based on the results achieved from the optimization model, the peak runoff, TSS and TN were found to reduce by 13%, 38% and 24%, respectively. The optimal number of LID controls for the BUNUS catchment was also found to be 25. The LID cost analysis was also performed using MOPSO to find out the best combination of LIDs in the catchment for the maximum runoff and pollutants reduction with the minimum cost. It can be concluded that urbanization will greatly affect both peak discharge and the quality of surface runoff. Applying LID and redirecting the surface runoff to the LID units can greatly reduce the surface runoff and improve the water quality. Hence, the significant role of LIDs in peak runoff reduction and water quality improvement could not be ignored
Electromechanics modelling of the effects of myocardial infarction on left ventricular remodelling / Leong Chin Neng
Get PDFMyocardial infarction (MI) is one of the diseases with the highest mortality rate. Following MI, myocardium experiences abrupt changes in its loading condition due to the presence of infarct. In response to such changes, myocytes undergo adaptations to maintain homeostasis. However, maladaptation can happen and lead to remodelling, in which the left ventricle (LV) gradually loses its function and eventually turns into heart failure. Nevertheless, the mechanisms underlying LV remodelling are still poorly understood. In this study, a generic LV model was developed, incorporating realistic fibre orientation and excitable contracting myocardium. It was demonstrated that the developed model is capable of reproducing physiological LV functions, including action potential propagation, LV pressure and cavity volume, LV twisting and wall thickening. Subsequently, the generic LV model was utilised to investigate the effects of the infarct state on LV regional mechanics, including the interaction between non-contractile infarct and contractile myocardium. It was found that infarct transmural extent (TME) is more important than infarct size in determining LV regional mechanics impairments. Neighbouring contractile myocardium and non-contractile infarct induce a mechanical tethering effect, which elevates with infarct TME, at the border zone (BZ). Such mechanical tethering causes the BZ to have high systolic fibre stress, elevated energy expenditure and reduced myocardial energy efficiency, which are believed to give rise to infarct extension. The generic LV model was then modified into a patient-specific model, incorporating patient-specific infarcted LV geometry and optimised regional material properties, to study the correlation between infarct extension and myocardial mechanics impairments, including the underlying mechanisms responsible for the impairments. Among the observed myocardial mechanics impairments, only the depressed myocardial energy efficiency was found to be correlated with infarct extension. The depressed myocardial energy efficiency was due to inadequate generation of contraction force, which, at least in part, owing to inadequate stretching of myocardium at end-diastole (the Frank-Starling law). Although a stiff infarct can prevent infarct expansion, results of this study showed that it can also cause the neighbouring myocardium to be under stretched at end-diastole, thereby depressing the generated contraction force and energy efficiency during systole, which were found to be correlated with infarct extension of the neighbouring myocardium
Economic determinants of energy intensity: A country panel analysis / Fatemeh Dehdar
No full textEfforts to lower energy intensity increased initially as a result of rising fuel prices following the first and second oil shocks, which subsequently became serious owing to mounting evidence that fossil fuels are a major cause of climate change and global warming. Energy source is a key problem associated with climate change as oil and gas, and coal constitute major components of fossil fuels. However, the extant literature remains divided on the determinants of energy intensity. For the purpose of filling this gap, this study modeled energy intensity and used panel annual data from 84 countries, (divided to stable and unstable countries for the second research question) from 1980 to 2012. In order to find out the sign and magnitude of the relationships, the current study applied Generalized Method of Moments (GMM). The first research question investigates the relationship between trade and energy intensity in global panel and the effects of exports, imports and export diversification is tested by including them separately in the energy intensity model. FDI, urbanization and industrialization are also included in the model. Results revealed that trade openness significantly and positively affect energy intensity, through increase in the economic activities. Similarly, exports and imports have significant and positive effects on energy intensity. Export diversification positively and significantly affect energy intensity, determining the fact that the more diversity of exports production, results in less energy intensity. Results show that energy prices and urbanization are not statistically significant in all of the estimations. FDI represents highly significant contribution in improving energy efficiency and decrease of energy intensity in all of the models. Increase in industrialization will lead to increase in energy intensity in all of the estimations. Results of the second research question revealed that, FDI in particular has a highly significant contribution towards lowering energy-intensity, as its coefficients were negative and highly significant at 1 percent in all three groups of countries. However, urbanization had no impact on energy intensity levels in all three groups of countries, while industrialization and trade exacerbated energy intensity in the global panel of countries. Whereas trade showed no relationship with energy intensity among stable and unstable countries, industrialization worsened energy intensity among stable countries. Institutional quality had a highly significant (1 percent) and positive impact on reducing energy intensity in all three groups of countries. The third research question of this study is regarding the direction of relationship between institutional quality and energy intensity in global panel. Prior to Granger causality test, the stationary properties of variables are tested applying Im–Pesaran–Shin (IPS) and Levin–Lin–Chu (LLC) panel unit root tests. Based on the results from these tests, both energy intensity and institutional quality are stationary. Applying GMM estimation, panel VAR model is estimated which is followed by panel VAR Granger causality Wald test. Results of Granger causality test shows that there is unidirectional causality running from institutional quality to energy intensity. The quality of environment is considered as a public good and provision of public goods are affected by the institutional quality
Enhancing the performance of IR-based traceability recovery of requirement artifacts using noun phrases / Mashahi Khalafalla Dafaalla Abdelrahman
No full textRequirement traceability can be considered as a measure of software quality to help achieve validation, verification, and reusability. Neglecting traceability leads to less maintainable software. Creating traceability links after-the-fact, known as traceability recovery, is a tedious and time-consuming process when it is done manually. Therefore, information retrieval (IR) methods have been used to automatically identify traceability links between the artifacts. However, as a result of limitations of the software engineer and the IR techniques, the performance of the IR methods is negatively affected. There is no IR method that is able to recover traceability links between artifacts with high precision and high recall, such as in Vector Space Model (VSM), the retrieved false positives cause low precision results. Nevertheless, VSM is widely practiced as it considers the simplest linear algebraic method, easy to understand and use for non-IR experts. It allows ranking of documents concurring their probable relevance, and there are many tools and open-source implementations which implement VSM such as RETRO and ReqSimile. The research aims to assist software engineers (analysts) during the process of recovering traceability links between software artifacts by suggesting the appropriate type of phrases, which enhance the performance of IR method. The research objectives are: 1) To investigate IR methods for traceability recovery; 2) To propose a method that achieves high performance (as high recall and precision as possible) in traceability recovery; 3) To empirically validate the proposed method through an experimental analysis to demonstrate its ability to improve the performance (as high recall and precision as possible) in traceability recovery. A comparative experiment is done by extracting noun phrases (NP), verb phrases (VP), and combination of noun and verb phrases (NPVP) from three benchmarking datasets namely CM1, MODIS, and PINE. VSM is applied, the result is evaluated in terms of recall and precision and the result showed that indexing NP only tends to outperform VP, NPVP, and all terms by achieving high recall and precision as possible
Rural poverty and urban proximity in Sabah, Malaysia / Jeron Joseph
No full textOne of the United Nations Sustainable Development Goals (SDGs) is to eradicate extreme poverty globally by 2030 in all countries including Malaysia. While Malaysia is close to achieving this target, poverty still persists in the state of Sabah. Therefore, this study examines the determinants of household poverty in rural Sabah with a focus on urban proximity. A purposefully designed survey instrument was used to gather primary data on a total of 407 rural households in 78 villages, spread across 16 poorest districts of Sabah. In addition, Geographic Information System (GIS) data on sample households and villages was collected to construct an index of urban proximity – travel time to the nearest town centre or “industrial core”. The empirical analysis utilizes multiple proxy measures of poverty such as human capital deprivation and lack of productive assets as outcome variables. For all of these measures, multivariate econometric models of household poverty model are estimated using ordinary least-squares regression method to determine the correlates of poverty. Consistent with the core-periphery model of Krugman (1991), we found that rural households with shorter commuting distance to urban centres have lower level of poverty in terms of human capital and asset ownership. This would indicate the level of poverty in terms of physical asset would depend on the proximity level of urban areas and rural households. This finding is robust to control for a host of demographic correlates of poverty and the presence of natural resources in the village, the choice of specific dimensions of poverty studied and the use of an aggregate index of household poverty (constructed using principal component analysis). Qualitative data obtained through in-depth face-to-face interviews with 10 village representatives and 15 poor households also confirms the importance of proximity to urban centres for household poverty. Respondents highlighted a variety of ways in which communication infrastructure and geographic location interact to influence travel time to urban and in turn affect their livelihood choices and household well-being. Lastly, econometric analysis of the determinants of urban proximity at the village level indicates that the distance to urban centres is primarily determined by policy variables (e.g. road infrastructure) and natural geographic barriers (e.g. presence of a river). These findings together highlight that investment in public infrastructure in rural areas can generate significant welfare gains by improving living standard and reducing spatial poverty in East Malaysia
A computational study of water mobility on smooth surface, cavities and porous structure with hydrophilic and hydrophobic coatings / Yong Kok Wee
No full textThis research focus on water mobility and discovers a new phenomenon where droplet accelerates on a hydrophilic cavity surface when sliding down from a hydrophobic surface. The kinetic energy of droplet increases six (6) times higher than before sliding into the first cavity. This finding is useful for creating an effective way of filling liquids into cavities for passive microfluidics related devices. The work consists of validating cases using Computational Fluid Dynamics (CFD) software. The first part of the research reviews the literature regarding CFD modelling of a water droplet (i) sliding down on a surface, (ii) detachment in a gas-flowed microchannel and (iii) jumping upon coalescence on a superhydrophobic surface. Then, this research continues with the investigations regarding the water retention behaviour in porous structures, i.e., an ideal structure and an actual porous metal structure, and further investigates the effect of different static contact angles and liquid drainage rates in a reservoir for each type of porous structures. Also, this research develops a method to quantify additional parameters for porous metal i.e., the structural homogeneity and the number of junctions besides the other parameters like pores per inch and porosity. With that, the present research able to relate the structural variations and its effect on the distribution of water saturation in the porous structures. In details, it detects the presence of large pores in the porous metal geometry, i.e., two times larger than the small pores that reduces the capacity in retaining water
Access to renal transplantation and post-transplantation prognosis (ReTRAPP) study of adults in Malaysia / Peter Gan Kim Soon
No full textIntroduction
Renal transplantation (RT) is recognised as the preferred treatment modality for
end-stage renal disease. However, Malaysian transplantation rates have been low
compared to other countries. Numerous clinical determinants have been associated with
renal transplant recipient' (RTRs) health, which is the main focus of the healthcare
fraternity. Coincident with the rising interest for equitable healthcare, many studies in the
high-income countries have examined the disparities in RT. On the contrary, little is
known about the association of socioeconomic gradient of RTRs on the access and
outcome of RT in Malaysia, a low- and middle-income country. ReTRAPP was designed
to explore the factors that limit access as well as assess the association of socioeconomic
status (SES) on the access and outcome (survival rate, quality of life and financial burden)
of RT.
Methodology
Collection of qualitative data involved semi-structured interviews with eight key�informants, who are identified by detailed stakeholder analysis. Their responses were
used to explore current RT policy and service availability and to identify relevant themes.
Quantitative data examined from the National Renal Registry of Malaysia for RTRs
above 18 years between 2002 and 2011 (n=1234 recipients).Cox's regression was used to
evaluate the association of SES on access to RT and post-transplantation survival rate.
iv
A quantitative study using a survey was administered to 409 RTRs in 6 public
health facilities in Greater Kuala Lumpur. Linear regression was used to determine the
association of SES on quality of life and logistic regression for association of SES and
catastrophic health expenditure (CHE).
Results
The in-depth interviews are categorised and described by the socio-ecological
model, which provided a framework better to understand the barriers and solutions to RT
in Malaysia. Results from the thematic analysis illustrate a complex interplay of personal,
cultural, and environmental factors. Lower household income was associated with
reduced access to renal transplantation (adjusted PTrend = 0.001). Additionally, patients
with higher educational attainment have a better survival rate post-transplantation
(adjusted PTrend < 0.001). Mean scores for all WHOQOL domains were reduced for RTRs
with low SES compared to high SES. After multivariable adjustment, educational
attainment and household income continued to affect all WHOQOL domains
significantly. 22.7% of RTRs experience CHE due to post-transplantation care.
Household income is the only SES indicator to show statistical significance with Middle
40% household income group and Bottom 40% household income group having 4.7 times
and 5.3 times more risk for CHE.
v
Conclusion
ReTRAPP was conducted to explore the barriers that limit RT and evaluate the
social inequalities in access and outcome of RT. Specific barriers and solutions
highlighted in ReTRAPP indicate a need for policy change in the health service delivery
model to improve the RT rate. ReTRAPP further highlights the disparities in access and
post-transplantation care of RTRs. These findings provide healthcare leaders with
opportunities to reduce disparities through a better understanding of the delivery of care.
Considering the impact of socioeconomic differentials on disparities in healthcare, a
multidiscipline partnership from various stakeholders is necessary to address the
socioeconomic inequality in access to care and health outcomes for RTRs.
Keywords Renal Transplantation, Socio-Economic Status, Access to Renal
Transplantation, Outcome of Renal Transplantation, Malaysi
Determinants of defense expenditure in South Korea / Lee So Yeon
No full textThis research pointed out the importance of defense spending as an „economic
means‟ for national security in South Korea while due to the aftermath of US-China
trade war, the threats and tension between North Korea and other neighboring
countries such as China have become much more severe. In this context, an empirical
study was conducted to investigate the factors determining national defense
expenditure with secondary data from 1960 to 2018. The domestic factors namely
economic growth, arms trade, the threat of North Korea and the Republic of Korea
(ROK)-United States (US) defense alliance were established as those explanatory
variables. The findings showed that the effect of threats and alliance factor on defense
expenditure was important in explaining the South Korean defense expenditure. This
paper suggested that strengthening the ROK-US-Japan defense alliance, promotion of
Official Development Assistance, and adoption of Women's basic military training
system for contributing to long-term defense security and national interests of South
Korea
Knowledge, attitude and practice towards tuberculosis and the effectiveness of a tuberculosis education program among nurses employed in tuberculosis centers in Libya / Muftah Abdusalam Elbahloul
No full textNurses make up by far the largest group of healthcare workers in any part of the world,
playing an important role in the direct management of tuberculosis (TB) patients and
facing a high risk of infection. Therefore, this study was conducted to explore the
knowledge, attitude, and practice towards TB among professional nurses in Libya and the
impact of an educational intervention on their knowledge, attitude and practice.
A cross-sectional design using self-administered validated questionnaire was conducted
to explore the nurses’ KAP towards TB. A total of 384 nurses in tuberculosis centres in
Libya participated in the study. TB education intervention was carried out from February
to August 2017. A sample of 100 TB nurses was randomly allocated into intervention and
control groups. The intervention group received health education regarding tuberculosis
using a developed module, while the control group did not receive any education.
Knowledge and attitude scores for both groups were evaluated using a self-administered
validated questionnaire at baseline, immediate after intervention, three, and six months.
Practice score was assessed only at baseline, three, and six months. For the KAP survey,
384 nurses were included. Eighty four (21.9%) were males and 300 (78.1%) were
females. Majority of them (85.2%) had low level of knowledge on TB; only 80 (20.8%)
had positive attitude towards TB and 326 (84.9%) had unsatisfactory level of practice
regarding TB.
The knowledge level was found to be significantly associated with age, educational level,
work experiences and residence (p = < 0.05). The attitude of nurses towards TB was
significantly (p = < 0.05) associated with gender, residence and work experience only.
There were significant associations of gender, education level and work experience with
practice among the nurses. Knowledge was significantly associated with practice among
the nurses towards TB (p <0.001).
iv
The TB educational intervention program was found to be effective immediately after
intervention, as the knowledge score improved by 40.08 (95% CI 41.77, 38.39) (p <
0.001) among the intervention group. The knowledge scores remained stable at 3-month
and 6-month follow-up. Likewise, there was significant improvement in attitude score
with a mean difference of 1.769 (95% CI 1.88, 1.65) (p < 0.001). The attitude scores
remained stable at 3-month and 6-month follow-up. Similarly, there was improvement in
practice score with a mean difference of 18.23 (95% CI 16.12, 0.17.43) (p < 0.001). The
practice scores remained stable at 6-month follow-up. In Conclusions, most of nurses in
tuberculosis centres in Libya had low levels of knowledge, negative attitude and
unsatisfactory practice towards TB. Knowledge was found to be associated with practice.
The educational intervention carried out was effective in improving the nurses’
knowledge, attitude and practice towards TB over time. Within the control group, there
were no significant differences in mean scores of knowledge, attitude and practice over
time. There were significant differences in knowledge, attitude and practice scores
between intervention and control groups over time (p < 0.001).
Key Words: Nurses, Libya, Knowledge, Attitude, Practice, Effectiveness, Tuberculosi
Enhancement of regeneration ratio and thermal durability for regenerated fiber Bragg grating based on pre-annealing treatment and multimaterial fibers / Nurul Asha Mohd Nazal
No full textRegenerated fiber Bragg grating (RFBG) or also known as regenerated grating (RG) is the creation of the temperature resistant grating through thermal erasure of seed grating (SG) followed by a rebirth of new grating in a annealing process. RG has shown to be a promising fiber Bragg grating component for operation under very high ambient temperature condition. Nonetheless, further investigation and improvement are required to better understand its formation mechanism and to enhance its performance. This study aims to enhance the regeneration ratio and thermal durability of the RG based on pre-annealing treatment and multimaterial fiber. In this work, the effect of the pre-annealing treatment by CO2 laser on regenerated grating formulated in few-mode fibers (FMFs) (two-mode and four-mode step-index fibers) is experimentally investigated. In the preparation, the pristine FMFs were first treated with direct CO2 laser annealing followed by a slow cooling procedure to reduce the internal stresses in the fibers before the grating inscription. After the thermal regeneration process, the produced RGs were then subject to a thermal durability test at 1050°C for 10 hours. In the comparison against the results from the RGs formulated in non-treated FMFs, the finding indicates that RGs in treated fibers have a better regeneration ratio and thermal resilience. It is believed that the thermal stress relaxation and structural rearrangement in the fiber glass are the major factors that lead to the lower grating recovery during the state of thermal regeneration process and higher degradation in the grating strength in a longer exposure period. The elimination and reduction of stresses in the fibers by the laser pre-annealing treatment in the earliest stage enables the grating to be formed in a more thermal stable condition, hence, RGs with prolonged lifespan can be produced. In addition, the study of grating regeneration was extended by fabricating RG in the new class of multimaterial fiber. The finding demonstrates that RG fabricated in the multimaterial fiber has exceptional performance with higher regeneration ratio value as compared with other common commercial fibers. The ultrahigh ratio in the regeneration of grating is correlated to the nano-crystallisation phenomenon of multicomponent in the fiber during regeneration process at high temperature. The results in the thesis provide an understanding of the mechanisms that involve during grating regeneration as well as to improve the effectiveness of RG as an extreme temperature sensor