Volume 34 (04) July 2022

Hot-dip galvanizing is an efficient technique to control the corrosion of substrates. Producing blemish-free coatings is a challenging task. Continuous work is done on galvanizing technology to achieve excellent surfaces; thus, flaws are encountered at intervals in all continuous galvanizing and galvannealed process. Most of each very small galvanized defect can appear like a draff particle, draff trapped actually a tiny lot of the blemishes found in hot-dipped galvanizing coatings. Also, almost all defects take place due to a roughed or mechanically dented surface, poor bath chemistry management, inadequate washing of the parts, and less maintained apparatus. Thus, the coated products, which are manufactured by galvanizers, have to develop the excellence of the line instrument, the heat treatment management, and the Zn bath in sequence to touching the hard and tough quality essential for automotive uses and applications. This review paper first discusses different types of galvanized coating defects, and then discusses different coating defects like Bare spot, Distortion, Dross, Touch marks, Dents, Rough Coating, Ash Deposit, Mechanical Damage, Blow out, Runs, Uncoated or Ungalvanized Surface, Reactive and Non-reactive steels welded together, Puddling and suggests possible remedial measures to be taken care; at the end, it summarize and concluded.

Keywords : Galvanizing; defects; corrosion; failure; galvanized product

Welding is the process of coalescence of two metals/alloys for creating a seamless joint, is a quintessential fabrication process utilised in almost every manufacturing sector. There is a range of welding processes that are used according to their features and the requirement of the fabricator. The tungsten inert gas (TIG) welding process is an extensively used welding process owing to its inherent characteristics like high weld quality, surface cleanliness, and autogenous welding mode. Unfortunately, the TIG process suffers some drawbacks, the most pronounced one is the shallow weld bead and low depth of penetration (DOP). This renders the process unusable for welding thicker sections in a single pass and consequently requires multiple passes which adds to the expenditure. A modification to this process is the A-TIG welding where A stands for Activated, the method utilises activating flux material to augment the penetration depth and depth to width ratio (DWR) of the weld bead. The current work is comprehensive and focuses mainly on the basics of the A-TIG process, understanding of weld pool dynamics that are governing the depth of penetration, analysis of various flux materials for their effects on different metals/alloys and finally the outcomes fetched from using A-TIG process on different commercially important alloys.

Keywords: TIG; depth of penetration; depth to width ratio; activating fluxes; A-TIG

Civilization and urbanization are the two key demands of humans in the 20th century. Over the last few decades, a considerable number of the human population have moved to urban areas. This phenomenon has led to an explosion of the population in some of the major cities around the globe, including in Saudi Arabia. Urban Heat Island (UHI) is a climatic condition in which urban settlements experience increased air temperature than their neighboring rural counterparts. The UHI is attributed to the anthropogenic modification of land surfaces, population growth, urban development, and its consequential production of waste heat, which is endangering human health and the environment as well as the quality of living. Series of factors have been responsible for UHI, including building orientation, material albedo, land use, high-rise constructions, and human activities. The present study investigates the significance of the UHI features and their relation to building energy consumption. A list of contributing factors to UHI was identified and analyzed. The study suggests that there is a positive relationship between urban greening and urban material concerning energy consumption. Thus, this is a potential study gap that needs to be addressed to analyze the impact of UHI, particularly in the context of Saudi Arabia.

Keywords: Urban heat island; energy consumption; environment; buildings

Interfloor leakage is amongst the highest claims reported to the Strata Management Tribunal. This defect affects strata communities directly and indirectly in cost of repair, occupant safety, health and disputes. Regulation 55 of the Strata Management (Management and Maintenance) Regulation 2015 under Strata Management Act 2013 defines interfloor leakage as any evidence of dampness, moisture or water penetration, and has underlined the work process of interfloor inspection. However, issues are investigating the cause of leakage and repair costs, and determining who is responsible for the repair. Conducting defect assessment by standards is the collection of systematic information to evaluate building performance, investigate defect elements and recommend appropriate repairs. The research concept framework examines the effect or influence of each construct on another construct. Constructs are three, namely, interfloor leakage management, legislation and owner satisfaction. Based on the literature review, the conceptual framework is produced, and each of these constructs is developed with several dimensions to be tested. The sequential exploratory design method is used with a combined approach of qualitative interviews and discussions with experts in the field of property management and building pathology to form a questionnaire for distribution to the management. This research is essential to decide how to reduce disputes, discuss the costs of repair and select a party to execute repairs that create quality strata management that benefits the owners, management and stakeholders.

Keywords: Interfloor leakage; building defect; strata management; dispute; building condition assessment report

Water quality issues had been the main concern in worldwide as water resource keeps being polluted. River acts as the main source of drinking water, habitat for aquatic life, agriculture and industry. Poor in water quality led to the increase n water treatment expenses, water scarcity and affect health. River pollution is caused by industrial discharge, sewage and wastewater, chemical fertilizers and pesticides and mining activities. This paper aims to review and comments on factors to be incorporated in water quality study. Water quality index and pollutants are found to be the critical factors. USA, Canada, Iraq, Thailand, Vietnam and Malaysia used different parameters in calculating WQI. The parameters being considered in the WQI are then classified the river according to their classes and usage. Department of Environment (DOE) Malaysia has highlighted three main pollutants in water quality study which are Biochemical Oxygen Demand (BOD), Ammoniacal Nitrogen (NH3N) and Suspended Solid (SS) due to their great influence on WQI calculation. However, standard treated water quality in Malaysia is still based on Environmental Quality Act, 1974 which is nearly 50 years ago. Emerging pollutants which are mainly organic compounds present as pharmaceuticals and personal care products are found in water resources nowadays and the treatment should be improvised along time. Some modification of class on usage of water as irrigation should be considered and the relevant of considering two oxygen demands in calculating WQI (BOD and COD).

Keywords: Water quality; water resources; water quality index; Malaysia

The research attempt to increase flexibility in shop floor and improve rate of production through maintenance engineering policies. The research is grounded on analysis of data collected from manufacturing based MSMEs and review of literature and data of spare parts published in referred journals. The study derives a further framework model comprising three strategies (Supply chain management, inventory management, and maintenance engineering) to improve rate of production. The aforesaid process is used to identify problems that occur during machine breakdown. The paper provides a research substitute machine to manage problems during breakdown of machines so that production is not hindered.

Keywords: Supply Chain Management, Inventory Management, Maintenance Engineering, Substitute Machine, Shop Floor Flexibility.

Computer-Aided Diagnosis (CAD) in MRI image processing can assist experts in detecting abnormality in human spine image efficiently. The manual process of detecting abnormality is tedious, hence the use of CAD in this field is helpful to increase the diagnosis efficiency. The segmentation method is an important and critical process in CAD that could affect the accuracy of the MRI spine image’s overall diagnosis. There are various segmentation methods commonly used in CAD. One of the methods is segmentation using thresholding. Thresholding approaches divide the area of interest by identifying the threshold values that can separate the image into desired grayscale levels based on its pixel’s intensity. This study focuses on investigating the optimal approach in segmenting lumbar vertebrae on the MRI images. The steps involved in this study include pre-processing (normalization), segmentation using local and global thresholding, neural network classification, and performance measurement. 20 images are used to evaluate and compare the segmentation methods. The effectiveness of the segmentation method is measured based on the performance measurement technique. This preliminary study shows that local thresholding outperforms the global thresholding approach with an accuracy of 91.4% and 87.7%.

Keywords: CAD; MRI; image processing; segmentation; otsu

Rice Husk has been utilized as a mineral admixture, cement replacement option, and filler in cement concrete as it provides several advantages such as improved strength values and environmental benefits related to the disposal of waste materials and to reduce the carbon dioxide emissions resulting from production of cement worldwide. In this study, flexural behavior of reinforced concrete beams using rice husk ash as a partial replacement of fine aggregates is investigated. For this purpose, four types of concrete mixtures were produced using rice husk ash as a partial replacement of fine aggregates at replacement levels of 0%, 10%, 15% and 20%. The produced reinforced rice husk ash concrete prism specimens were cured in water and tested to determine the ultimate load and ultimate deflection at 28 days of curing. The test results depicted that, the maximum ultimate load carried by reinforced rice husk ash concrete beam is 39.4 KN with 10% rice husk ash at 28 days and minimum ultimate load is 19.02 KN with 20% rice husk ash used as a partial substitute of fine aggregates at 28 days. The minimum ultimate deflection of 0.97mm occurred with 10% rice husk ash as a partial replacement of fine aggregate at 28 days of curing. Hence, this study concludes that 10% RHA can be utilized as a partial replacement of fine aggregates to provide strength in concrete and to reduce the environmental burden of rice husk waste. The results of this study will also provide a way forward to address the recent issues in construction sector, such as depletion of raw materials and increasing cost of construction.

Keywords : Rice husk; concrete; carbon dioxide emissions; flexural strength; fine aggregates; eco-friendly concrete

The use of concrete-filled steel tube (CFST) columns is highly encouraged nowadays in modern multistory structures. The major reason is the extensive resistance offered by the hollow steel column to high compression. Nevertheless, further studies and data are desirable to exhaustively characterize these members and their connections to other members, such as beams. This paper investigated the behavior of concrete-filled columns connected to I-beams by through plates. Three simple types of plate connections (easy to assemble and construct) were proposed and evaluated. The behavior of these connections was examined under static loading by using advanced finite element based software (ABAQUS). The modeling techniques used in this study were validated by comparing the numerical results of a through plate connection model with the results of two relevant experimental studies. The proposed connections were classified as semi-rigid connections according to Eurocode-3. These connections were able to move the plastic hinge away from the column panel zone. The maximum plastic rotations of all connection types were greater than 40 mrad. The failure mode, and moment-rotation curves of the concrete-filled column to steel beam connections were discussed based on numerical results. The influence of through plate material and through plate thickness were evaluated via a parametrical study.

Keywords: Numerical study; concrete filled column; I-beam; through plate; ABAQUS

Unsupervised lung segmentation method is one of the mandatory processes in order to develop a Content Based Medical Image Retrieval System (CBMIRS) of CXR. There is limited study found on segmentation of mobile chest radiographs, that is relatively important especially for very sick patients whenever their radiographs will be taken using portable X-Ray machine.The purpose of the study is to present a solution for lung segmentation of standard and mobile chest radiographs using fully automated unsupervised method, based on oriented Gaussian derivatives filter with seven orientations, combined with Fuzzy C-Means clustering and thresholding to refine the lung region. A new algorithm to automatically generate a threshold value for each Gaussian response is also proposed. The algorithms are applied to both PA and AP chest radiographs from both public JSRT and private datasets from collaborative hospital. Two pre-processing blocks are introduced to standardize the images from different machines. Comparisons with the previous works found in the literature on JSRT dataset shows that our method gives a reasonably good result. Performance measures (accuracy, F-score, precision, sensitivity and specificity) for the segmentation of lung in public JSRT dataset are above 0.90 except for the overlap measure is 0.87. The median of overlap score for the private image database is 0.83 (standard machine) and 0.75 (mobile machines). The algorithm is also fast, with the average execution time of 12.5s. Our proposed method is fully automated, unsupervised, with no training or learning stage is necessary to segment the lungs taken using both a standard and mobile machines, and useful for the application of the CBMIRS.

Keywords: Chest radiograph; Unsupervised lung segmentation; Fuzzy C-means; Gaussian derivatives; Medical image processing

In ensuring competitiveness and employability, architectural graduates nowadays have been observed to acquire new skills to complement their conventional architectural trainings. The main purpose of this paper is to discuss the hard and soft skills acquired by the architectural students via the architectural design project requirements, which is also categorized as project-based learning. The study utilizes mixed-mode methods through questionnaire survey and in-depth interview. As this is a preliminary study, the number of respondents for the survey is 32, while for the in-depth interview, only eight students have participated. From the findings, it can be concluded that skills such as video presentation (hard skill), teamwork and communication skills (soft skill) are essential for architecture students undertaking project-based learning. The findings of this study will be used to benefit investigations in student’s skill developments in project-based learning with larger number of respondents. It is hoped that the findings will be adopted into the architectural education field to better equip future graduate architects with skills which are necessary for the industry.

Keywords: Architecture student; hard skill; soft skill; project-based learning; architectural design studio

The mathematical model for temperature regime thermal analysis evaluation of convective heat dryer has been done. Control volume analysis was adopted in this work while taking note of all the feasible heat transfer mechanisms around the system. Mathematical expressions for the energy, exergy, entropy generation as well as destroyed exergy were derived using the control volume. The consumed energy, exergy, entropy generation and exergy destruction of the dryer were computed. The system temperature gradually increased from its initial room temperature of 270˚C to 720˚C at approximately 2700 secs. The temperature thereafter dropped and stabilized to about 670˚C at 4600 secs while the element dried gradually. The moisture removal curve followed the same trend as that of the temperature with gradual variation from 0.5 to 13.2g/mol. The peak energy from the system is approximately 958J against the useful exergy of 443J which shows that 46.24% of the expended energy was actually useful for the drying purpose and about 10.23% was lost. The energy and exergy efficiencies were also computed and results showed that the efficiencies are functions of temperature just like other influencing parameters which has to be technically controlled. Peak energy efficiency of approximately 54.6% was recorded in the dryer with the peak exergy efficiency of 23.4%. The dryer also yielded a better dried product as compared with the traditional means of drying.

Keywords: Exergy efficiencies; Dryer; Moisture content; Temperature regime evaluation; Exergy destructio

The Charpy V Notch toughness (CVN) of steel is an important property while considering structural and heavy loading conditions. In welded structures, CVN is attributed to many variables like composition of steel, heat input of welding, pre- and post-heat treatments of the weldment, type of welding process etc. The regression analysis works accurately for three to four variables. The property of weldment is associated to more than three-four variables. So this conventional regression analysis couldn’t capture associated trends among the variables due to their non-linearity. This complexity is countered well by artificial neural network (ANN) modelling. In the present work, artificial neural network approach is utilized for the prediction of CVN of ferritic steel welds, which is multi-phase complex engineering material. The multilayer perceptron (MLP) method is used for formulating the neural network models. Numerous models were made by adjusting the hyperparameters and a best model was selected having least training error. The crucial results obtained from this model where analysed from response graphs and contour plot. This (MLP) approach for formulating neural network model was proved to be efficient after validation procedure and the same model could be exploited well for predicting accurate value of CVN in a very time and cost-effective manner.

Keywords: Charpy toughness; ferritic steel; artificial neural network; multilayer perceptron

The image retrieval system has been used to provide the needed correct images to the physicians while the diagnosis and treatment process is being conducted. The earlier image retrieval system was a text-based image retrieval system (TBIRS) that used keywords for the image context and it requires human’s help to manually make text annotation on the images. The text annotation process is a laborious task especially when dealing with a huge database and is prone to human errors. To overcome the aforementioned issues, the approach of a content-based image retrieval system (CBIRS) with automatic indexing using visual features such as colour, shape and texture becomes popular. Thus, this study proposes a semi-automated shape segmentation method using a 12-anatomical point representation method of the human spine vertebrae for CBIRS. The 12 points, which are annotated manually on the region of interest (ROI), is followed by automatic ROI extraction. The segmentation method performs excellently, as evidenced by the highest accuracy of 0.9987, specificity of 0.9989, and sensitivity of 0.9913. The features of the segmented ROI are extracted with a novel global Hu-F descriptor that combines a global shape descriptor, a Hu moment invariant, and a Fourier descriptor based on the ANOVA selection approach. The retrieval phase is implemented using 100 MRI data of the human spine for thoracic, lumbar, and sacral bones. The highest obtained precision is 0.9110 using a normalized Manhattan metric for lumbar bones. In a conclusion, a retrieval system to retrieve lumbar bones of the MRI human spine has been successfully developed to help radiologists in diagnosing human spine diseases.

Keywords: Image segmentation; active shape model; feature extraction; image retrieval; human spine; MRI images

Kenaf fibre has a low environmental impact because it is recyclable, light density and strong to be used as a product. Natural fibres, especially kenaf fibre, are undertilised and understudied in 3D printing technology. 3D technology is gaining traction to replace traditional methods because it saves cost and production time. This study focuses on producing kenaf composite materials that can be used as a feeder for 3D printing. This study used different fibre compositions (20,25,30) % mixed with polypropylene set at 190 ˚C temperature, 45 rpm speed, and 25 minutes. The material was left to cool to form clot to go through for the rheology process, and injection analysis was performed using Autodesk Moldflow Insight 2014. This study showed that a mixing temperature of 190 ˚C was suitable for forming a high shear mechanism. Kenaf fibre was treated in an alkaline solution of NaOH to 3 hours to prevent damage to the surface of the filler fibre in composites. Kenaf fibre at 6% of NaOH solution reaches a higher value for mechanical strength and roughness, resulting in better mechanical interlocking between the fibres and the matrix. In addition, analysis from Autodesk Moldflow Insight 2014 reveals that at 200 ˚C injection temperature pretend, the shear rate is higher creating smoother melt flow characteristics.

Keywords: Kenaf composites; 3D printing; simulation; shear modulus

The objective of this study was to improve level of transit service of public transport bus routes in Baghdad city through the implementation of some remedial actions. Eight public transport bus routes were selected to evaluate and improve the Level of Transit Service (LOTS). These routes represent Al-Tahrir bus network (A) which was located in the center of Baghdad city (capital of Iraq). The suggested remedial actions include reduction of legal bus stops delay (B), the elimination of illegal bus stops delay (b), the elimination of signalized intersections delay (I), and the reduction of traffic congestion delay (C). These suggested remedial actions are leaded to improve the values of total delay, bus travel time, service frequency (headway), adjusted running speed, and capacity. The values of level of transit service for these transit performance measures were improved. The overall routes level of transit service were improved for bus routes No. (72, 36, 13, 114, 11, 30, 37, and 9) from LOTS (D, E, E, E, E, D, E, and E) to LOTS (C, D, C, D, D, C, D, and D) respectively. The overall network LOTS was improved from LOTS (E) to LOTS (D), indicating that the application of the suggested remedial actions was effective and suitable to improve the performance and Level of Transit Service for public transport bus routes in Baghdad city. Therefore, this study recommended to use the remedial actions which proposed by authors to improve level of transit service for others bus networks.

Keywords: Improvement; bus route; performance measures; LOTS; total delay; speed

Work Stress is a barrier towards productivity and efficiency in manufacturing sector. Various factors of stress interact with the demographics such as age, education, experience, marital status and smoking habits of workers. Different workers exhibit different reactions towards work stress. To enhance productivity, manufacturing industry is utilizing night shift. However, night shift work is against the natural tendency of humans. The impact of rotating shift in context of work-stress of the workers is an area of concern. To understand the impact of demographics and shift rotation on work-stress of the workers, a quantitative study was undertaken in a medium sized automotive organization. The case organization was explored through a survey questionnaire administered to both day and night shift workers and analysed through Non parametric Spearman correlation and Mann Whitney U Test. The study highlights the need for effective reward and gratification scheme (Young Worker Avg 3.12 – Old Worker Avg 3.82), taking care of old age workers (Muscle Pain Old Avg 4.47 – Young Avg 3.84), reducing the smoking habit (Depression Smoking Avg 3.79 – Non Smoking Avg 3.12) (Fatigue Smoking Avg 3.92 – Non Smoking Avg 3.06), fostering social community and teamwork. Night shift may enhance production but should not be accepted as an ideal solution. The downsides and ill effects of the unnatural night shift work in the form of work stress are identified and should be reduced by management.

Keywords: Stress management; demographics; shift rotation; manufacturing; productivity

The self-connected partially encased composite beams may be used rather than the conventional composite beams; those are connected by the concrete passing through the web-openings of the perforated profiles which works as shear connectors. This technique minimizes the construction cost and enhances the load carrying capacity and ductility of this kind of structures better than the perforated steel beams. The presented work investigates the performance of perforated steel and partially-encased composited self-connected simply supported beams applied to three-points of loading. The effect of the openings shape and the presence of concrete on the performance of the beams are investigated by testing eight specimens of perforated steel and composite beams. The openings’ shapes of perforated steel profiles and composite beams were square, rectangular and circular. The solid steel profiles are taken as control beams in both exposed and encased specimens. The composite beam constructed using perforated steel profile with square openings was reinforced with conventional reinforcement, and setting its stirrups passing through the openings to improve the self connection. The failure modes, strain behaviours, and load-deflection curves were extensively discussed. The composite beams reinforced with perforated steel profiles exhibit higher composite performance than that reinforced with solid profiles. The concrete encasement improved the local deformation performance of the perforated steel profiles (50-300%), leading to a more ductile behaviour and a higher dissipation of energy. The square openings provide higher connectivity than other shapes due to the better arrangement of openings and presence of reinforced concrete.

Keywords: Perforated steel profiles; partially encased composite beam; self-connected; flexural performance; shear performance

The influence of polymer/nanocomposites (Acrylete-Styrene-Acrylonitrile (ASA)/ Nanosilica (Si)) asphalt binder aging and performance characteristics was investigated. ASA was used at 5% while nanosilcia was blended in 3, 5 and 7% concentrations by the weight of asphalt. Temperature sensitivity, aging resistance and viscoelastic properties of the asphalt binders were evaluated by conducting physical and dynamic shear rheometer (DSR) testing procedures. The tests were performed under unaged and short-term aged conditions by simulating the aging of asphalt in a Rolling thin film oven (RTFO). Additionally, the Adaptive Neuro-Fuzzy Inference System (ANFIS) modelling technique was adopted to predict the short-term aged behaviour of asphalt binders by using the viscoelastic properties of asphalt in an unaged state. The experimental outcomes from the DSR tests showed that the complex modulus (G*) was increased and the phase angle (δ) was reduced for the modified binders, indicating an improvement in the viscoelastic properties compared to the control asphalt binder. Furthermore, the considerably small difference in the G* and δ between the binders in unaged and RTFO aged states indicated that the modifiers had a positive effect in terms of improving the aging resistance of the asphalt binders. Moreover, the ANFIS model prediction capacity, which was assessed by the Coefficient of Determination (R2) and Mean Squared Error (MSE) and Mean Average Percentage Error (MAPE) was shown to be capable of accurately predicting the short term-aging behaviour of asphalt binders from the asphalt binder viscoelastic properties in an unaged state with an R2 value of 0.977, MSE of 0.00032 and MAPE of 0.286.

Keywords: Polymer nanocomposite; acrylete-styrene-acrylonitrile; nanosilica; dynamic shear rheometer; short-term aging; artificial intelligence

Health pandemics such as Covid-19 have drastically shifted the world economics and boosted the development of automation technologies in the industries for continuous operation without human intervention. This paper elaborates on an approach to dynamically track and grasp moving objects using a robot arm. The robot arm has an eye-in-hand (EIH) configuration, where a camera is installed on the robot arm’s end effector. The working principle of the robot arm in this paper is mainly dependent on the recognition of augmented reality markers, i.e., Aruco markers, placed on the dynamically moving target object with continuous tracking. Then, the proposed system updates the predicted location for the markers using the Kalman filter for performing grasping. The proposed approach identifies the Aruco marker on the target object and estimates the object’s location using previous states, and performs grasping at the exact predicted location. When extracted information is updated, the vision system also implements a feedback control system for stability and reliability. The proposed approach is tested using simulation of the dynamic moving object with different speeds and directions. The robot arm with the Kalman filter can track and grasp the dynamic object at a speed of 0.2m/s with a 100% success rate while obtaining an 80% success rate at a speed of 0.3m/s. In conclusion, the moving object’s speed is directly proportional to the grasping time until it reaches the threshold speed for the camera in identifying the Aruco markers. Future works are required to improve the dynamic visual servo algorithm with motion planning when obstacles are present in the path of robot grasping.

Keywords: Eye-in-hand; Aruco Markers; Kalman Filter; Feedback Controller; Velocity Threshold

Nowadays, detection of driver’s fatigue is a major concern in vehicle design, road safety and transportation research. Driving tasks requires full attention from the drivers while operating the vehicle. Occasionally, drivers are exposed to perform other activities such as talking to a passenger and using an in-vehicle technology or phone which is known as secondary task while driving. Thus, this study aims to analyse the driver’s performance via three types of physiological measurements in a simulated condition. An integrated approach by combining subjective and objective methods were used in this study. There are Karolinska Sleepiness Scale (KSS), Electroencephalogram (EEG) and Heart Rate (HR). Twelve participants were recruited to evaluate their responses towards different types of secondary tasks and disruptions in 25-minutes of driving duration. The findings showed that there are differences in physiological responses for this driving session. Beta Activity shows higher event-related power modulation values from start until the end of the driving session. In conclusion, the type of disruption during driving and secondary tasks shows different findings towards driver driving performances. This study can be used as reference to drivers and related agencies by taking into account the physiological effects of driver’s performance based on different secondary tasks and disruptions while driving.

Keywords: Fatigue; safety; behaviour; EEG; heart rate

Greensand casting is a casting process that uses mixture of silica sand with addition of control additions which are bentonite clay and the presence of water. Control additions influence the mechanical properties of greensand casting mould, for this study focuses on the permeability. Bentonite clay acts as a binder and activated by water to develop strength and plasticity thus the greensand casting mould can be formed. Permeability is ability of gas to pass through the moulding mixture aggregates in order to reduce the defects due to trapped gasses in mould cavity such as blow holes or pin holes. The objective of this study is to investigate the effect of control addition (water and clay) on the permeability number of silica sand sample (tailing sand) from former tin mine site in Tronoh, Perak. Experiments are conducted according to American Foundrymen Society (AFS) standard of procedures. Sand sample is sieved using mechanical sieve shaker to size of 425 μm. Cylindrical test pieces dimensioning of Ø50 mm×50 mm in height from various mixtures of sand-clay–water ratios are compacted by applying three ramming blows of 6666 grams using Ridsdale-Dietert metric standard rammer. The test pieces are tested for permeability with Ridsdale-Dietert permeability meter. The results show that clay and water have affected the permeability of silica sand sample and when more water and clay added, into the moulding mixture, the permeability is found decreased. The appropriate allowable water and clay content are crucial for permeability number of greensand casting mould.

Keywords: Permeability; moulding mixture; silica sand; sand casting and greensand casting mould