Optical test strip for trace Hg(II) based on doped sol-gel film.

Optical test strip based on the use of Br-PADAP as a sensitive reagent immobilised into sol–gel thin film for detection of Hg(II) in aqueous solution had been thoroughly carried out. It has a square-sensing zone (1.0 cm × 1.0 cm) containing the sensitive reagent necessary to produce response to trace level of mercury. This method offer sensitivity and simplicity in detecting Hg(II) as no prior treatment or extraction is required. A linear response was attained in the Hg(II) concentration in the range of 0.5–2.5 ppm with calculated limit of detection of 6.63 ppb. This method also showed a reproducible result with relative standard deviation (R.S.D.) of 2.15% and response time of ∼5 min. Interference studies showed that Al(III), Co(II) and Ni(II) significantly interfered during the determination. The developed sensor has been validated against Atomic Absorption Spectroscopy method and proven comparable

Field grown Acacia mangium : how intensive is root growth?

Under rainfed conditions, root development of trees can be very unpredictable and variable, depending on the amount and distribution of rainfall received. This becomes more critical when the rainfall is seasonal and the soil has a high clay content. Our investigation dealt with the root development of Acacia mangium established as plantation forest on a soil with heavy clay texture in Kemasul Forest Reserve, Malaysia. The distribution of active roots was measured at 9- and 21-month-old plantations using the radioactive 32P injection method. Growth at different distances from the tree base and at different soil depths was studied. After nine months of field planting, we found that roots were mostly concentrated at the surface within 1000 mm distance from the tree base. At one year after the first measurement, roots were traced as far as 6400 mm away. A large part of these roots, however, were detected within 3700 mm distance in the upper 300mm soil. At this stage, roots still did not go deeper than 450 mm depth, probably due to the high clay content at lower depth and low pH. This rapid root growth indicates that below-ground competition can be very intense if this species is established as a mixed-species plantation

Segmentation and characterization of masses in breast ultrasound images using active contour

The active contour or Snake is a computer generated curve, used to trace boundaries of images. This paper presents the application of Snake for the segmentation of masses on breast ultrasound images and the characterization of the segmented masses as malignant or benign. Initially, the Balloon Snake is chosen to segment the masses. Comparison on the masses areas segmented by the Balloon Snake is done against the areas traced by radiologist. Experimental result shows that from fifty masses tested, the Balloon Snake successfully segment the masses with accuracy of 95.71%. Then, a mass is characterized as benign or malignant using a proposed method namely the semi-automated characterization (SAC) method. The method is based on the segmented masses produced by the Balloon Snake. The criterion of angular margin is considered in characterizing the masses as malignant or benign by the SAC method. The characterization reading of a mass by the SAC method is compared with thirty sets of characterization readings of a mass by different radiologists. The comparison is made in terms of sensitivity and specificity values. Based on the values, the receiver operating characteristics (ROC) curve is plotted for each set of comparison. From the thirty sets of comparisons, it is found that the area under curve of all the thirty ROC curves are greater than 0.7. The value implies that the SAC method gives high accuracy in characterizing benign from malignant mass. Since the method is based on the segmented masses by the Balloon Snake, the value also implies that the accuracy of Balloon Snake in segmenting the images is high (95.71%)

Rotan manau intercropped with rubber: rate of root growth between three and four years after planting

Efficient fertiliser management depends partly on understanding the active root distribution. In the present study, the active root distribution of 3- and 4-y-old plantation grown rotan manau (Calamus manan) was assessed using isotope tracer technique. For the 3-y-old rotan manau, three distances from the plant base (0.5, 1.0 and 1.5 m) at 5 and 30 cm depths were examined. For the 4-y-old plants, two distances, viz-á-viz at a centre between two rattan plants and another in the middle between two rattan plants and two rubber trees were studied. The isotope used was 32P, applied as a solution with KH2PO4. The rotan manau plants had been established under mature rubber plantation. High proportions of feeder roots were found at 0.5 and 1.0 m distances at the surface (5 cm depth) for the 3-y-old plants. Uptake of 32P was also observed for the application at 1.5 m distance for both depths but the counts were small. Statistical analysis gave a highly significant difference within the distances and within the different depths. For a better synchronisation between fertiliser application and plant uptake, it seems that application at approximately between 0.5 and 1.0 m distance around the plant is most appropriate at this age. At four years after planting, important uptake was obtained only for the two plants located near the application area. Anyhow, to some extent it reflected that roots had already extended for another 1 m compared to the 3-y-old plants

Biology of Macrolophus caliginosus (Heteroptera: Miridae) predator of Trialeurodes vaporium (Homoptera: Aleyrodidae)

Macrolophus caliginosus Wagner (Heteroptera: Miridae) is a highly polyphagous predatory bug, which has proven to be effective in controlling many insect pests of greenhouse vegetables (eggplant, tomato, and cucumber) especially whiteflies, aphids, and thrip. It is mainly used as a biological control auxiliary against T. vaporariorum Westwood (Homoptera: Aleyrodidae). The greenhouse whitefly, Trialeurodes vaporariorum is particularly harmful to tomato plants grown under the greenhouse. It has become prevalent whenever crops are frequently sprayed with insecticides. Biological control is becoming important for controlling this insect pest. A mirid bug management programme has been developed for an Integrated Pest Management (IPM) in tomato. The objective of the programme was to keep the predator population densities high enough in order to maintain T. vaporariorum and other insect pest populations below the economic threshold. In this study, it was very important to determine the biology of predator in term of its life cycle, behaviour at different stages, fecundity, longevity and searching abilities, in order to provide detail data for formulating the means of control against whitefly. Results of this study indicated that Macrolophus caliginosus adults fed on whitefly larvae of all stages from the first larval stage to the pupal stage. The predator consumed the preys at almost similar daily rates (average of 5.94 per day). The study implies that M. caliginosus, with its life cycle, predation, longevity and fecundity and host preference, is a beneficial insect to combat against whitefly

Geospatial approach for Landslides Vulnerability Assessment of Physical Infrastructures in Sireh Park, Johor Bahru

According to the landslide records between 1993 and 2019 in Malaysia, 171 individuals lost their lives, many others sustained injuries and numerous families evacuated. Additionally, infrastructures and vehicles incurred damage. Even though landslides present a risk to human life, environment, and infrastructures, there are few studies on landslides vulnerability in Malaysia with most of them focusing on social vulnerability neglecting the physical vulnerability. Consequently, a dearth of information on the vulnerability of an area to landslides may amplify the risks associated with landslides, and the relevant authorities in both the landslide-prone and affected regions may not implement the appropriate mitigation measures. The aim of this study is to estimate vulnerability of elements at risk to landslide in the hazard’s affected area of Sireh Park. An indicator based method was used to calculate the relative vulnerability index for each of the elements at risk. In applying the method, experts assigned weights to the indicators and their respective sub indicators based on their significance to landslides vulnerability. The indicators were grouped into clusters, the total values of weights for all the clusters equals to 1. The results of the study showed that about 252 elements at risk are exposed to landslides in Sireh Park, out of which 226 (89.7%) are buildings, while 26 (10.3%) are roads. The general level of buildings' vulnerability to landslides in the study area is relatively low, however about 20.4% of the buildings display a high degree of vulnerability. Meanwhile, the general vulnerability of roads sections to landslides is averagely high, with about 54.8% of the roads sections exhibiting a high degree of vulnerability while 16.1% exhibits low degree of vulnerability. The study can help stakeholders to identify locations with high landslide vulnerability and guide the development of mitigation measures and emergency preparedness plans to reduce the potential impact of landslides in the study area

Comparison between GVF snake and ED snake in segmenting microcalcifications

Snake, active contour or deformable active contour has been widely used in medical image segmentation area. In this paper, comparison between Gradient Vector Flow (GVF) snake and Enhanced Distance (ED) snake in segmenting microcalcifications is carried out. The performance is measured based on actual area of the average percentage difference traced by expert radiologists. Results obtained shows that the values of average percentage difference for the GVF and ED snake are 4.3% and 6.68% respectively. These results indicate that the GVF snake has better performance with 95.7%

Chemical enhancement materials for grounding purposes

It is an aim of this work in finding the best performed chemical enhancement material in order to provide the lowest impede path for fault currents to be dispersed into the earth in the shortest time possible. These fault currents are typically due to transients and they could be dangerous to the power system, equipment in it and the personnel involved with the system. Hence, it is desired that a grounding system is installed to provide such path to clear these fault currents from the power system in the manner that danger could be reduced. Such transients are generated by lightning, or switching action. Note that in this study, only lightning strike is considered. Lightning could create impulsive transient during its direct or indirect strikes to power system. This problem is normally prevented by installing a suitable grounding system to the power system. A grounding system will create a path for transient to be safely dispersed into the earth by providing lowest resistance path. This can be easily done using either natural or chemical enhancement materials. However, this work only reported the findings of having chemical enhancement materials in the vicinity of grounding system for protection against lightning. It is found that sodium chloride demonstrated the best performance in being enhancement material for earthing system on top of sodium thiosulphate, magnesium chloride, cuprum sulphate, and ammonium chloride

Individual tree measurement in tropical environment using terrestrial laser scanning

Detailed forest inventory and mensuration of individual trees have drawn attention of research society mainly to support sustainable forest management. This study aims at estimating individual tree attributes from high density point cloud obtained by terrestrial laser scanner (TLS). The point clouds were obtained over single reference tree and group of trees in forest area. The reference tree is treated as benchmark since detailed measurements of branch diameter were made on selected branches with different sizes and locations. Diameter at breast height (DBH) was measured for trees in forest. Furthermore tree height, height to crown base, crown volume and tree branch volume were also estimated for each tree. Branch diameter is estimated directly from the point clouds based on semi-automatic approach of model fitting i.e. sphere, ellipse and cylinder. Tree branch volume is estimated based on the volume of the fitted models. Tree height and height to crown base are computed using histogram analysis of the point clouds elevation. Tree crown volume is estimated by fitting a convex-hull on the tree crown. The results show that the Root Mean Squared Error (RMSE) of the estimated tree branch diameter does not have a specific trend with branch sizes and number of points used for fitting process. This explains complicated distribution of point clouds over the branches. Overall cylinder model produces good results with most branch sizes and number of point clouds for fitting. The cylinder fitting approach shows significantly better estimation results compared to sphere and ellipse fitting models

Autonomous arm application in clinical waste management

Autonomous Arm is operated with a gesturecontrol glove through human movements. Is a robotic concept inspired from manufacturing industries used for heavy task-load in the production line. High portability with < 5kg and modular design for different use case and attachment to different robot. Customizable with different functions of control with different preferred operating system (OS). Designed to accompany human or through longdistance control in managing waste indirectly