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PublicationCorrelation analysis of lightning and flash flood events using Pearson model in Southeast Peninsular Malaysia(IEEE, 2023-07)Flash flood is a natural disaster that causes many casualties and economic losses; it has become prevalent in Malaysia, where several events have been reported showing a possible correlation between lightning, rain, and flash floods. The lightning and rainfall intensity associated with flash flood events, are analyzed between January and April 2022 for three events (cases) within a distance of 100 km from Universiti Teknologi Malaysia, Johor. The data supplied by Tenaga Nasional Berhad Research Sdn. Bhd. (TNBR), Department of Irrigation and Drainage (DID) and Malaysia Meteorological Department (MetMalaysia) were evaluated for statistical discrepancies, which is a different approachable method by limiting the criteria for each data source. This research aims to investigate the relationship between the number of lightning occurrences with the amount of rain in 24 hours by applying the Pearson correlation coefficient (r) and determine the relationship strength between lightning and rainfall intensity parameters by implementing the rainfall-lightning ratio (RLR) change to rainfall-lightning rate, which is commonly used to evaluate the relationship between rainfall and lightning. This study found that the r-values between lightning and rain range from 0.4 to 0.7, which correlates well with rainfall and is considered an acceptable correlation. The different values due to the number of lightning and rain occurrences are inconsistent for each independent case. According to the findings, lightning data may be utilized in association with rain. Therefore, the accuracy of the existing flood forecasting system may be improved.
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PublicationUnconfined compressive strength assessment of stabilized marine soil with cockle shell powder as sustainable material on subgrade pavement(IOP Publishing, 2023)Sustainable infrastructure is one of the sustainable development goals (SDGs) introduced by the United Nation. By utilizing waste materials as recycled and reused materials in construction, it offers great benefits to people, the economy and the environment for sustainable infrastructure in geotechnical project development. The low strength of marine subgrade pavement soil can be improved by chemical stabilization from abundant natural waste near the coastal area. The use of seashells such as cockle shells in powder formed can be considered a potential sustainable natural waste additive in replacing lime and cement for stabilized marine soil. Yet, its potential performance in improving geotechnical properties has not extensively been investigated. Thus, the unconfined compressive strength of stabilized marine soil with cockle shell powder (CSP) was assessed experimentally. The treated soil specimens were mixed with 2.5%, 5%, 7.5% and 10% of CSP (by dry weight of the soil sample) and prepared in the cylindrical dimension of 38 mm in diameter and 76 mm in height prior to unconfined compression test based on the optimum moisture content (OMC) obtained from the compaction test. All experiments were carried out in accordance with British Standard. The results show that the CSP can improve the strength of stabilized soil. The highest strength is 636.785 kPa for soil mixed with 10% of CSP which 157% increase compared with untreated soil. Therefore, the results of the study have shown that the addition of CSP to marine soil has improved significantly the unconfined compressive strength in soil stabilization, especially for pavement such as highways, airport runways and parking areas.
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PublicationEffects of physical and mechanical properties of soft soil on subgrades performances in Lubuk Bayas village, Serdang Bedagai Regency(IOP Publishing, 2023)Generally, the existence of soft soil in Indonesia will be a problem in the construction of highway construction. One factor that influences and needs to be known in road construction is the characteristics of the subgrade where the pavement construction will be placed on it. Poor soil characteristics can cause bumpy road surfaces, cracks, or other road damage. Therefore, before carrying out a soil improvement, it is necessary to know its characteristics through the physical and mechanical properties of the subgrade. This research was conducted in Lubuk Bayas Village, Serdang Bedagai Regency, North Sumatra Province. Tests of physical properties in this study include sieve analysis, water content, specific gravity, plasticity limit test, and liquid limit test. The soil shear strength test and California Bearing Ratio (CBR) test were carried out to test the mechanical properties using a Dynamic Cone Penetrometer (DCP). From the results of testing the physical properties of the soil, it was found that Samples 1, 2, and 3 were fine-grained soils with the percentage of soil passing the No.200 sieve greater than 50%. The USCS classification system shows that samples 1 and 2 of the soil are in the Lean Clay (CL) group, while sample 3 is in the Fat Clay (CH) group. Samples 1, 2, and 3 include soils with high plasticity because the PI value is >17. The results of testing the mechanical properties of the soil Sample 1 obtained the value of c = 0.1299 kg/cm2 and Ø = 13.2°, in Sample 2 obtained the value of c = 0.1075 kg/cm2 and the value of Ø = 11.2° and in Sample 3 obtained the value of c = 0.1275 kg/cm2 and the value of Ø = 11.9°. DCP testing on samples 1, 2 and 3 obtained CBR values of 5.35%, 4.73% and 3.15%. From the CBR results, it can be seen that the soil in this location has a low soil bearing capacity, so if it is to be used as a subgrade layer, it will be necessary to repair the soil first so that structural damage does not occur in the future. Soil improvement can be made by stabilizing the soil using natural materials to maintain environmental sustainability. Natural materials that can be used include sand with certain gradations, stone ash, palm shell ash, and various other natural materials
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PublicationRemoval of Chromium (VI) in aqueous solution by charcoal adsorbent derived PET plastic waste(IOP Publishing, 2023)This study was conducted to assess the potential of charcoal and activated charcoal derived Polyethylene Terephthalate (PET) as adsorbent through the experiment of chromium hexavalent [Cr (VI)] removal from aqueous solution. The study aims to investigate the optimum adsorption conditions for Cr (VI) removal in aqueous solution under diverse adsorption operating conditions, namely pH, contact time, agitation speed, adsorbent dosage, and initial concentration. The diameter of the charcoal produced was 600 μm. The results showed that 80 % and 90 % of Cr (VI) removal were achieved by using charcoal and activated charcoal, respectively, at pH 5, 150 rpm, 60 min of contact time, 0.5 g of adsorbent dosage, and 0.1 mg/L of Cr (VI) initial concentration. The removal of Cr (VI) was mainly affected by adsorption operating conditions and the physicochemical properties of adsorbents. Langmuir and Freundlich adsorption isotherms were applied to model the adsorption behaviour and determine the adsorption capacity of both PET charcoal adsorbents. The adsorption isotherm plot was well fitted with the Langmuir model.
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PublicationA review on enhancement of oil palm solid waste through torrefaction(Springer, 2023-09)Biomass is one of the renewable energy sources and is easily obtained in Malaysia. Due to the substantial amount of biomass waste generated by agricultural activities, Malaysia actually has great potential for biomass power generation. The oil palm industry is the largest contributor to biomass waste in Malaysia, particularly oil palm solid waste. The raw oil palm solid waste produced low-quality products during thermochemical conversion. Thus, the torrefaction process is one of the approaches to improve the characteristics of raw oil palm solid waste. Therefore, the objectives of this study are to review the production and characteristics of solid biofuel from oil palm solid waste via the torrefaction process. Torrefaction is a thermal conversion method of biomass in the low-temperature range of 200–300 °C. Different reaction conditions such as temperature and reaction time lead to several characteristics of biofuel products. The solid fuel of pretreated oil palm solid waste has enhanced overall quality and its characteristics after torrefaction.