The Effects of Mortality and Influence of Pheromone Trapping on the Infestation of Oryctes rhinoceros in an Oil Palm Plantation

Kamarudin, Norman Hj,Wahid, Mohd Basri,Moslim, Ramle,Ali, Siti Ramlah Ahmad Korean Society of Applied Entomology 2007 Journal of Asia-Pacific Entomology Vol.10 No.3

The infestation levels of O. rhinoceros were investigated in the oil palm trunk heaps in three replanting blocks (Blocks A, B and C) at Sepang, Selangor, Malaysia. These blocks had different densities of pheromone trapping: high (11 traps per ha, Block B), normal (1 trap per 2 ha, Block C), while no pheromone trapping was conducted in (Block A. Without pheromone trapping, the infestation levels of O. rhinoceros can reach a maximum density of between 25 to 50 individuals per $m^2$ (IPMS). The O. rhinoceros population was still detected in the heaps up to more than two years (at 26 months after replanting). With high density trapping, infestation levels were maintained below 10 IPMS and was not detected in the heaps after a period of 16 months of replanting. In the normal trapping density, the population was also maintained below 10 IPMS but had sustained itself in the heaps for up to 24 months. The mortality factors associated with the larval stages sampled within these replanting blocks was determined by visual symptoms with subsequent verification with microbial analysis. The analysis was narrowed down to detect only bacteria (Bacillus thuringiensis and B. popillae), virus (Oryctes virus) and fungus (Metarhizium). In Block A, the population of O. rhinoceros in the trunks was reduced drastically at 14 months after replanting (MAR), which could be due to the high mortality (88%) of the third instar larvae, 3 months earlier. In Block B, the percentage mortality for the larval stage was always highest at the third ins tars (between 21-82%). In Block C however, the mortality of the third instars was low, never exceeding 35%. In these sampling blocks, the infection of Metarhizium seem to be less dominant compared to virus or bacteria The k factor analysis indicates density dependence among the third instar larvae had contributed to the change in its population density in Block A. Therefore, with proper manipulation of pheromone traps and targeted application of disease agents (i.e virus, fungus and bacteria), the population of O. rhinoceros can be managed more effectively in an oil palm replanting.

Pheromone mass trapping of bagworm moths, Metisa plana Walker (Lepidoptera: Psychidae), for its control in mature oil palms in Perak, Malaysia

Norman Kamarudin,Siti Nurulhidayah Ahmad,Othman Arshad,Mohd Basri Wahid 한국응용곤충학회 2010 Journal of Asia-Pacific Entomology Vol.13 No.2

The bagworm, Metisa plana Walker (Lepidoptera: Psychidae), is an important pest of oil palms in Malaysia. A serious infestation cause yield declines of 30–40% over 2 years after attack. Successful mass trapping depends on efficient removal of adults, which reduces the chances of mating, eventually causing a decline in the population. This study was conducted in three smallholder blocks where palm age varied from 6 to 16 years. Sticky vane traps were baited with four receptive females of M. plana and placed in three transects within each trapping plot. The percentage of female bags with eggs (i.e., those pupal bags housing the female with eggs that hatched) determined the effects of trapping on mating and reproduction success. Palm yield was compared between the trapping and control plots. The number of live larvae and the percentage of bags with eggs in the trapping plots were always relatively lower (9.1–28.2%) compared to the control plots (28.6– 48.6%). Trapping plots had relatively higher bunch weight (7.8–14.3 kg) compared to the control plots (4.5– 9.2 kg). The bunch weight in the trapping plots increased 22% after trapping compared to 15% in the control plot. Damage ratings on the fronds declined between 35–45% in the trapping blocks. Damage ratings declined between 20% and 27% in most control plots but increased 17% in one of the blocks with an increased bagworm population. There, mass trapping reduces the chances of bagworm mating and oviposition, which leads to lower populations and, therefore, lower frond damage and higher yields.

Effect of Matric Suction and Density on Yield Stress, Compression Index and Collapse Potential of Unsaturated Granite Soil

Mehrdad Kholghifard,Kamarudin Ahmad 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.8

Residual granite soil from Malaysia shows some problematic features such as: high void ratio, low natural dry density, and loose of apparent cohesion of the soil immediately after rain due to wetting. This study is aimed to evaluate the influence of suction and density on unsaturated behavior of the residual granite soil e.g., the yield stress (σc), compression and swelling indices (Cc, Cr), and collapse potential (CP). To do that, a modified oedometer was fabricated on the basis of the axis translation technique (ATT). Then, one-dimensional consolidation tests were performed under different suctions using the modified oedometer. The results showed a negligible increase in σc when the applied suctions were less than the air entry value. The σcvalues of dense soil samples were higher than that of loose soil samples regardless of the matric suction. Besides, the values of Cc appeared in three zones: saturation, desaturation and residual zones, while, Cr was independent of the matric suction. The difference of CP under similar matric suction indicated a hydraulic hysteresis behavior of the residual granite soil. However, the hydraulic hysteresis effect on the maximum CP was negligible.

The Effects of Mortality and Influence of Pheromone Trapping on the Infestation of Oryctes rhinoceros in an Oil Palm Plantation

Norman Hj Kamarudin,Mohd Basri Wahid,Ramle Moslim,Siti Ramlah Ahmad Ali 한국응용곤충학회 2007 Journal of Asia-Pacific Entomology Vol.10 No.3

Ultimate Bearing Capacity of Soft Soil Improved by DCM Columns: A Comparative Review

Ali Dehghanbanadaki,Ahmad Safuan A. Rashid,Kamarudin Ahmad,Nor Zurairahetty Mohd Yunus,Jagdish Telangrao Shahu,Mamata Mohanty 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.6

The use of deep cement mixing (DCM) columns for soil stabilization is an economical and reliable ground improvement technique that has been studied extensively. The aim of this article is to review the ultimate bearing capacity (UBC) of soft soils improved by DCM columns in a series of 1 g physical modelling tests. Reliable databases of 35 stabilized tests using end-bearing DCM columns and 42 stabilized tests using floating DCM columns are analyzed. The effects of the influencing parameters of undrained shear strength of the soil (Cus) and DCM columns (Cuc), and the area improvement ratio (α) on the UBC and bearing capacity (Nc = UBC/Cus) are discussed. The failure modes of the improved soil have been compared. The review results show that, for end-bearing and floating DCM columns, the role of α and the strength ratio between the columns and soil, respectively, are vital. The effect of the average end-bearing factor for DCM columns (Nc = 15.27) on the UBC was found to be higher than for floating DCM columns (Nc = 8.08). The experimental results were used to develop four computational models to estimate the UBC of stabilized soil improved by end-bearing and floating DCM columns.

Innovative method to prepare a stable emulsion liquid membrane for high CO₂ absorption and its performance evaluation for a natural gas feed in a rotating disk contactor

Bhatti, Inamullah,Qureshi, Khadija,Kamarudin, Khairul Sozana Nor,Bazmi, Aqeel Ahmed,Bhutto, Abdul Waheed,Ahmad, Faizan,Lee, Moonyong Elsevier 2016 Journal of natural gas science and engineering Vol.34 No.-

<P><B>Abstract</B></P> <P>This paper presents an innovative method to prepare a stable emulsion liquid membrane (ELM) for high CO<SUB>2</SUB> absorption in a natural gas feed. This new method achieved high throughput at low power consumption. The ELM prepared using this new method was characterized by determining the effects of the concentration of the ELM constituents, emulsification time, and speed on the emulsion droplet size (EDS) and stability. This was followed by a parametric study of the process parameters for CO<SUB>2</SUB> separation from natural gas in a rotating disk contactor (RDC)-based setup to evaluate the performance of a stable ELM. The results suggest that the retention time of the stable ELM in a RDC increases with increasing amount of absorbed CO<SUB>2</SUB>. The results support the fundamental development of the ELM process to achieve a high overall separation efficiency of CO<SUB>2</SUB> removal from natural gas with a relatively small contact time. This is the first parametric study of CO<SUB>2</SUB> absorption from a gas stream in ELM using a RDC as the contracting equipment. The results of the parametric study suggested that the factors of time, TEA concentration and RDC speed have significant effect on the CO<SUB>2</SUB> absorption from natural gas feed. It was identified that 4% TEA in ELM, 30 min operational time and 700 rpm speed of modified RDC system is suitable for maximum CO<SUB>2</SUB> absorption from gas mixture of CO<SUB>2</SUB>/CH<SUB>4</SUB>. Furthermore, the study suggested that the ELM containing 4% TEA can absorb 5.6 kmol/m<SUP>3</SUP> CO<SUB>2</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Preparation and characterization of stable emulsion liquid membrane (ELM). </LI> <LI> Parametric study of CO<SUB>2</SUB> absorption from natural gas in rotating disk contactor (RDC). </LI> <LI> Retention time of the stable ELM increases with increasing amount of absorbed CO<SUB>2</SUB>. </LI> <LI> Fundamental development of ELM process for high overall separation efficiency. </LI> </UL> </P>

Empirically Based Rainfall Threshold for Landslides Occurrence in Peninsular Malaysia

Abdul Muaz Abu Mansor Maturidi,Norhidayu Kasim,Kamarudin Abu Taib,Wan Nur Aifa Wan Azahar,Husna Binti Ahmad Tajuddin 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

Empirical rainfall thresholds for the purpose of shallow landslide forecasting are proposed for Peninsular Malaysia where numerous slope failures are reported due to the intense rainfall in conjunction with the humid tropical climate. Thirty-seven cases of landslide-triggering-rainfall were selected from 1993 to 2018 to identify the correlation between rainfall and shallow landslide through the analysis of specific rainfall events. The derived rainfall parameters were applied to establish two rainfall thresholds of (Imean-D) and (Imax-D) via practical methods. For the identical range of event duration 1 < D < 263 h, the (Imean-D) threshold formula was expressed as I = 17.5 D−0.722, while the (Imax-D) threshold was defined as I = 37.8 D−0.114. Both thresholds performed different functionalities with a primary goal of predicting shallow landslides. When both (Imean-D) and (Imax-D) thresholds were compared with the thresholds proposed by various studies worldwide, both dominated the upper positions. More rainfall is required for land sliding due to the high thickness of the Malaysian soil that is associated with the abundant tropical downpour. From the perspective of the antecedent, the period of prolonged precipitation or short heavy rainfall from 1 to 10 days can result in shallow landslides for Peninsular Malaysia. In the context of geology, the igneous rock type of granite has the highest susceptibility to the shallow landslide at 65%, despite other rock types of sedimentary and metamorphic. The threshold validation depicted all True Positive events for the (Imax-D) threshold, and one Negative False event for the (Imean-D) threshold. The (Imean-D) threshold was revised to acquire the new value, but it needed to deal with the possibility of False Alarm and the (Imax-D) threshold seemed to be more credible to represent the rainfall-induced shallow landslide threshold for Peninsular Malaysia.

A Study on UCS of Stabilized Peat with Natural Filler: A Computational Estimation Approach

Ali Dehghanbanadaki,Mahdy Khari,Ali Arefnia,Kamarudin Ahmad,Shervin Motamedi 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

This study applied two feed-forward type computational methods to estimate the Unconfined Compression Strength (UCS) of stabilized peat soil with natural filler and cement. For this purpose, experimental data was obtained via testing of 271 samples at different natural filler and cement mixture dosages. The input parameters for the developed UCS (output) model were: 1) binder dosage, 2) coefficient of compressibility, 3) filler dosage, and 4) curing time. The model estimated the UCS through two types of feed-forward Artificial Neural Network (ANN) models that were trained with Particle Swarm Optimization (ANN-PSO) and Back Propagation (ANN-BP) learning algorithms. As a means to validate the precision of the model two performance indices i.e., coefficient of correlation (R2) and Mean Square Error (MSE) were examined. Sensitivity analyses was also performed to investigate the influence of each input parameters and their contribution on estimating the output. Overall, the results showed that MSE(PSO) < MSE(BP) while R2 (PSO) > R2 (BP); suggesting that the ANN-PSO model better estimates the UCS compared to ANN-BP. In addition, on the account of sensitivity analysis, it is found that the binder and filler content were the two most influential factors whilst curing period was the least effective factor in predicting UCS.

Micro-Level Analysis of Marine Clay Stabilised with Polyurethane

Samaila Saleh,Nor Zurairahetty Mohd Yunus,Kamarudin Ahmad,Nazri Ali,Aminaton Marto 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.3

Soil stabilisation is one type of ground improvement technique regarded as effective in minimising foundation problems associated with marine clay (MC). In this paper, in-depth micro-level analysis was conducted on MC stabilised with 8% Polyurethane (PU). The effectiveness of PU as a stabiliser was evaluated using unconfined compressive strength (UCS) tests and one-dimensional consolidation tests. Mineralogy of MC was studied using X-ray diffraction analysis (XRD). Furthermore, field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDX) were used to discern the roots of improvement in the strength of MC. The result of XRD analysis identified the presence of Quartz, Montmorillonite, Calcite and Clinochlore. FESEM results discovered that MC showed crumpled, curled and flaked soil particles that have a fuzzy arrangement and cusp-like crystals in a joined fashion. The contact among the particles is surface-to-surface and surface-to-edge. The PU foam was composed of intramolecular closed cells that are non-homogeneous, non-identical, and of inconsistent average diameters of about 2.3 μm. Finally, EDX results revealed that O, C, Si, Al, Fe and N are the elements that contributed more than 96% of the composition of MC and PU.