Significance of intermodal freight modal choice criteria: MCDM-based decision support models and SP-based modal shift policies

This paper reviews modal choice decisions associated with intermodal freight transportation through decision support models based on the Multi-Criteria Decision-making (MCDM) techniques and modal shift policy as�sessments based on the Stated Preferences (SP) experiments. The objectives were to determine the relevant decision criteria and their relative significance, to define methods in use, and to identify respective policies that boost intermodality. Google Scholar database and manual search using identified keywords were conducted and references of the relevant articles were double-checked. Consequently, a total of 27 articles consisting of respective 18 and 9 MCDM-based and SP-based articles were reviewed in this study. The results showed that the most commonly used decision criteria were cost, CO2 emissions, delivery time, safety, reliability, flexibility, and frequency. The cost factor was assigned the highest weight in 22 articles (or 81.4%). Analytical Hierarchy Process (AHP) technique was implemented in 12 out of 18 MCDM articles (or 66.6%)). Successful application of MCDM methods (both single and integrated) showed the suitability of these methods for intermodal freight modal choice decision-making. The results of SP experiments revealed that cost reduction policies are more effective than policies addressing other factors to increase the demand for intermodal transportation

GEOGRAPHIC INFORMATION SYSTEM BASED SUPPORT VECTOR MACHINE MODELING FOR SOIL EROSION SUSCEPTIBILITY MAPPING

Soil erosion hazard has been recognized as one of the biggest environmental challenges. It becomes more problematic in human-altered mountainous watershed like Cameron Highlands. Literature survey revealed the issues of subjectivity in selecting erosion causative factors (CFs) for susceptibility modeling due to lack of specific guideline. To date, some crucial dynamic CFs are not considered and support vector machine (SVM) techniques are scarcely explored in the previous susceptibility mapping

GEOGRAPHIC INFORMATION SYSTEM BASED SUPPORT VECTOR MACHINE MODELING FOR SOIL EROSION SUSCEPTIBILITY MAPPING

Soil erosion hazard has been recognized as one of the biggest environmental challenges. It becomes more problematic in human-altered mountainous watershed like Cameron Highlands. Literature survey revealed the issues of subjectivity in selecting erosion causative factors (CFs) for susceptibility modeling due to lack of specific guideline. To date, some crucial dynamic CFs are not considered and support vector machine (SVM) techniques are scarcely explored in the previous susceptibility mapping

Assessment of morphological and hydrological parameters of Oyun River Basin, Nigeria

The study involves evaluation of basin area, slopes, shape of the basin as morphological parameters and analysis of flow frequencies for flood and low flows, developing unit hydrograph and analysis of rainfall intensity distribution in the study area as hydrological parameters. The morphological analysis of the basin yielded basin area, slope, elongation and circulatory ratio of 830km2, 0.57%, 0.46 and 0.35 respectively. For hydrological analysis, flow frequency, unit hydrograph and rainfall analysis were evaluated. The flood (peak) and low flows were fitted with Gumbel Extreme Value Type I & III model, and the recurrence intervals for low and peak flows of 0.0004m3/s and 3.5772m3/s were obtained as 4 and 44 years respectively. The mean annual maximum flow and mean annual runoff depth were estimated to be 7.97m3/s and 6.5mm respectively. This showed that the intensity of rainfall contributing to the volume of river discharge was 6.5mm/day. Unit hydrograph was developed for the river basin using SCS approach. More so, rainfall analysis was carried out to determine the flood and drought periods. The results indicated that Oyun river basin is relatively small watershed with elongated narrow shape and non-steep slope which contributed to relatively slower draining of water into the river. From the analysis, flooding is expected in the month of September while drought may be expected in the months of December to February. The results of this study will be useful to river basin managers in managing and planning of water resources and facilities development.Keywords: Hydrological, Morphological, River basin, SCS, Flood, Low flo

EVALUATION OF RAINFALL-RUNOFF EROSIVITY FACTOR FOR CAMERON HIGHLAND, PAHANG, MALAYSIA

Rainfall-runoff is the active agent of soil erosion which often resulted in land degradation and water quality deterioration. Its aggressiveness to induce erosion is usually termed as rainfall erosivity index or factor (R). R-factor is one of the factors to be parameterized in the evaluation of soil loss using the Universal Soil Loss Equation and its reversed versions (USLE/RUSLE). The computation of accurate R-factor for a particular watershed requires high temporal resolution rainfall (pluviograph) data with less than 30-minutes intensities for at least 20 yrs, which is available only in a few regions of the world. As a result, various simplified models have been proposed by researchers to evaluate R-factor using readily available daily, monthly or annual precipitation data. This study is thus aimed at estimating R-factor and to establish an approximate relationship between R-factor and rainfall for subsequent usage in the estimation of soil loss in Cameron highlands watershed. The results of the analysis showed that the least and peak (critical) R-factors occurred in the months of January and April with 660.82 and 2399.18 MJ mm ha-1 h-1year-1 respectively. Also, it was observed that erosivity power starts to increase from the month of January through April before started falling in the month of July. The monthly and annual peaks (critical periods) may be attributed to increased rainfall amount due to climate change which in turn resulted to increased aggressiveness of rains to cause erosion in the study area. The correlation coefficient of 0.985 showed that there was a strong relationship rainfall and R-factor

Comparative analysis of single- and multi-criteria container transport modes in Peninsular Malaysia

This study investigates the transport of containers via intermodal transport network of Peninsular Malaysia by comparatively analysing the use of trucks, trains and ships with respect to time, CO2 emission and cost. The study is aimed at proposing the best route/mode of container transport in Peninsular Malaysia. ArcMap and MATLAB were employed to identify the single-objective route/modal choices. The multi-criteria route/modal choices were achieved by integrating the Simple Multi-Attribute Rating Technique (SMART) and sensitivity analysis. The single-objective results indicated that the use of trucks on road was the fastest mode of container transport. However, the combination of ship and train was the most environmental-friendly for Case 1, while transport by ship generated the least CO2 emission for Case 2. Train was found to be the cheapest mode of container transport, followed by ship and truck. It can be inferred from the multi-criteria analysis that container transport via rail is the ideal and least-cost route and mode of transport.</p

Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice

A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is fit for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water on selected properties of reinforced concrete and its durability, thus, further research is recommended

Kinetic and Prediction Modeling Studies of Organic Pollutants Removal from Municipal Wastewater using Moringa oleifera Biomass as a Coagulant

This study investigated the potential of Moringa oleifera (MO) seed biomass as a coagulant for the removal of turbidity, biochemical oxygen demand (BOD), and chemical oxygen demand (COD) of municipal wastewater. Triplicated laboratory experiments using MO coagulant added at varying treatment dosages of 50, 100, 150, 200 mg/L, and a control (0 mg/L) treatment were performed for a settling period of 250 min at room temperature. Kinetics and prediction variables of cumulative turbidity, BOD, and COD removal were estimated using simplified first order and modified Gompertz models. Results showed that the maximum removal of turbidity, BOD, and COD were 94.44%, 68.72%, and 57.61%, respectively, using an MO dose of 150 mg/L. Various kinetic parameters, such as rate constant (r), measured (REm) versus predicted (REp) cumulative removal, and specific pollutant removal rate (&micro;m), were also maximum when an MO dose of 150 mg/L was added, the standard error being below 5%. The developed models were successfully validated over multiple observations. This study suggests low cost and sustainable removal of turbidity, BOD, and COD of municipal wastewater using MO seed biomass as a coagulant

Assessing the suitability of GlobeLand30 for land cover mapping and sustainable development in Malaysia using error matrix and unbiased area Estimation

Global Land Cover (GLC) maps have been extensively used as background data for numerous applications such as land-use planning, climate change monitoring, and urban planning. While countries in Europe and North America have greatly developed land cover maps, several developing countries in Asia and Africa lack such vital data sources. GlobeLand30’s 30 m resolution dataset has the potential to meet the mapping needs of these developing regions. However, differences in accuracy of the dataset between countries can be significant making it unsuitable to adopt regional accuracy directly for assessing individual country’s accuracy level. Therefore, it is critical to develop reliable localized assessments. This research assesses the accuracy of GlobeLand30 for Malaysia using multiple evaluation approaches. Seven classes of land cover data were evaluated using 197 samples in the country. An overall accuracy of 63.45% and 65.70% was obtained from the Error Matrix using sample counts and the new unbiased area estimator respectively. We conclude that the overall accuracy of GlobeLand30 in tropical developing countries like Malaysia is generally lower than the accuracy in developed countries and arid developing countries thereby requiring significant improvement for optimal use. However, despite the errors due largely to misclassification, the GlobeLand 30 data has the potential to complement other LULC data to estimate and monitor vital land-use changes in Malaysia and the ASEAN region in general for sustainable development

Advances and Challenging Issues in Subsurface Drainage Module Technology and BIOECODS: A Review

Subsurface drainage modules are important components of the Bio-ecological Drainage System (BIOECODS) which is a system designed to manage stormwater quantity and quality using constructed grass swales, subsurface modules, dry and wet ponds. BIOECODS is gradually gaining attention as one of the most ecologically sustainable solutions to the frequent flash floods in Malaysia and the rest of the world with a focus on the impact of the subsurface modules to the effectiveness of the system. Nearly two decades of post-construction research in the BIOECODS technology, there is need to review findings and areas of improvement in the system. Thus, this study highlighted the key advances and challenges in these subsurface drainage modules through an extensive review of related literature. From the study, more work is required on the hydraulic characteristics, flow attenuation and direct validation methods between field, laboratory, and numerical data. Also, there is concern over the loss of efficiency during the design life especially the infiltration capacity of the module, the state of the geotextile and hydronet over time. It is recommended for the sake of higher performance, that there should be an onsite methodology to assess the permeability, rate of clogging and condition of the geotextile as well as the hydronet over time