Nur Liza Rahim
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Nur Liza Rahim
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Nur Liza, Rahim
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Rahim, Nur Liza
Rahim, N. L.
Rahim, Nur Alis Addiena A.
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Scopus Author ID
55754434900

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Validation Of Shear Failure On Bolted Connection For Nyatoh Hardwood

2023-01-01 , Ujan X.L.A. , Karim A.R.A. , Sa’Don N.M. , Sahari S.H. , Nur Liza Rahim , Quenneville P.

The lack of consideration of brittle failure by the Malaysian Timber Standard (MS544-5) in the design of bolted connections for local hardwood can be seen from the unacceptable under-design performance shown by the code. This makes the design output costly because of the increased use of steel materials due to either bigger bolt diameters or larger bolt quantities required. The current study was conducted to examine the effectiveness of the existing design equations for bolted connections in Nyatoh hardwood. This present study was to propose a set of optimised equations that can be used for the retrofit design of wall-diaphragm connections in unreinforced masonry buildings. The row shear failure observed in the tested bolted connections of Nyatoh hardwood was also reported. Ten different bolted connection configuration details in the manner of a steel-wood-steel arrangement were tested, which all had a single row bolted connection. By using the linear regression method in analysing the experimental data obtained, a calibration factor for optimising the Row Shear Model (RSM) equation was identified. From the comparisons made between the experimental results and the strength predictions given by both MS544-5 and RSM, it was found that the design strength calculated from MS544-5 was too conservative for predicting the bolted connection strength in Nyatoh hardwood, whereas the RSM predictions were acceptable and recommended.

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Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia

2022-01-01 , Nur Liza Rahim , Sheng F.T.S. , Karim A.R.A. , Nabialek M. , Mohd. Mustafa Al Bakri Abdullah , Sroka M.

Steel-wood-steel connection is widely seen in many applications, such as timber structures. The stiffness of steel-wood-steel connection loaded parallel to grain for softwoods originated from Malaysia was investigated in this study. Numerical models have been developed in ABAQUS to study the stiffness connection. Softwoods of Damar Minyak and Podo have been selected in this analysis. The comprehensive study focused on the effect of bolt configurations on stiffness. Numerical analysis is carried out and the developed model has been validated with the previous study. Further investigations have been made by using the validated model. From this model, numerical analysis of the stiffness values have been made for various bolt configurations, including bolt diameter, end distance, bolt spacing, number of rows and bolts and edge distance. The result shows that the stiffness of bolted timber connections for softwood depends on the bolt diameter, number of rows and bolts, end distance and edge distance. Based on the result, stiffness increased as the diameter of the bolt, end distance, number of rows and bolts and edge distance increased. It is also discovered that the stiffness equation in Eurocode 5 (EC5) is inadequate as the equation only considered parameters which are wood density and bolt diameter. Other connection parameters such as geometry are not considered in the EC5 equation.

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Assessing the self-healings properties of nano -Ca(OH)â‚‚ - TiOâ‚‚ - ZnO materials used in monuments conservation works

2023 , Moncea Mihaela-Andreea , Deak Gyogy , Gheorghe (Dumitru) Florina-Diana , Norazian Mohamed Noor , Nur Liza Rahim

Consolidates based on Ca(OH)â‚‚ have been prepared as macro- and/or nanoparticles dispersed in different alcohols, regardless of the precursor nature. Their efficiency is related to the small dimensions of the particles and the dispersion media, which allows their penetration into the deteriorated material substrates, as well as to an increased reactivity towards COâ‚‚. Besides the consolidating effect there is a strong need for the newly developed materials to also tackle other properties like self cleaning and antimicrobial activity, especially with regards to white monuments. In this context the present work highlights the effect of treating with stable alcoholic suspension containing nano - Ca(OH)â‚‚ - TiOâ‚‚ - ZnO the physical support models consisting of mortar cubic samples from hydraulic / aerial lime, a commonly used materials in consolidation works.

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Computer simulations of end-tapering anchorages of EBR FRP-strengthened prestressed concrete slabs at service conditions

2023 , Chirawat Wattanapanich , Thanongsak Imjai , Reyes Garcia , Nur Liza Rahim , Mohd. Mustafa Al Bakri Abdullah , Andrei Victor Sandu , Petrica Vizureanu , Petre Daniel Matasaru , Blessen Skariah Thomas

This article examines numerically the behavior of prestressed reinforced concrete slabs strengthened with externally bonded reinforcement (EBR) consisting of fiber-reinforced polymer (FRP) sheets. The non-linear finite element (FE) program Abaqus® is used to model EBR FRP-strengthened prestressed concrete slabs tested previously in four-point bending. After the calibration of the computational models, a parametric study is then conducted to assess the influence of the FRP axial stiffness (thickness and modulus of elasticity) on the interfacial normal and shear stresses. The numerical analysis results show that increasing the thickness or the elastic modulus of the FRP strengthening affects the efficiency of the FRP bonding and makes it susceptible to earlier debonding failures. A tapering technique is proposed in wet lay-up applications since multiple FRP layers are often required. It is shown that by gradually decreasing the thickness of the FRP strengthening, the concentration of stress along the plate end can be reduced, and thus, the overall strengthening performance is maximized. The tapering is successful in reducing the bond stress concentrations by up to 15%, which can be sufficient to prevent concrete rip-off and peel-off debonding failure modes. This article contributes towards a better understanding of the debonding phenomena in FRP-strengthened elements in flexure and towards the development of more efficient computational tools to analyze such structures.

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The behaviour of Reinforced Concrete Beams by Using Expanded Polystyrene Beads and Palm Oil Fuel Ash as Replacement Materials

2024-01-01 , Osman M.H. , Chin L.Y. , Suraya Hani Adnan , Jeni M.L.M. , Jusoh W.A.W. , Salim S. , Nur Liza Rahim , Wysłocki J.J.

The Reinforced Concrete (RC) beams containing Expanded Polystyrene Beads (EPS) and Palm Oil Fuel Ash (POFA) as sand and cement replacement with a percentage between 10% and 30%were studied in terms of load-deflection behaviour. RC beam’s size was 1000×150×150 mm and simply supported at spaced 750 mm apart. The 10% of POFA without EPS shows a slight increase which is 0.26% higher than normal concrete in compressive strength. The ultimate load and flexural performance of RC beams with EPS and POFA exhibited a decreasing trend. All beams’ ultimate load exceeds the design value. The cracks of the RC beam may be classified as vertical flexural cracks, and some of the cracks can be classified as shear cracks based on the crack angle. As the percentage of EPS and POFA increases above 20% for all specimens, cracking starts to change to shear cracking.

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Improving Iron and Copper Uptake by Changing the Ratios in Root of Vetiver Grass

2023-01-01 , Halim N.S.A. , Hamzah N. , Baharudin F. , Zainuddin N.S. , Nur Liza Rahim , Kamil N.A.F.M. , Akbar N.A. , Zin N.S.M.

Phytoremediation using Vetiver grass (VG) has been used in the past few decades all over the world, but the effectiveness of its uptake mechanism in water has less been discussed especially in mixed metal conditions. Hence, the focus of this research was to determine and evaluate the heavy metal removal effectiveness of two heavy metals, copper (Cu) and iron (Fe), based on vetiver grass uptake and toxicity. Three treatments of Fe and Cu mixture were chosen, and individual concentrations act as a control. The vetiver grass at a height of 10 cm and a root length of 25 cm for each treatment was used and harvested on days 0,1, 3, 6 and 7. The roots were randomly cut, oven-dried and used the digestion method to extract the Fe and Cu in the root. From the result, vetiver grass has better Fe and Cu uptake ability in the mixture treatment compared to the individual treatment. Fe uptake is increasing up to 25.3 % in the presence of Cu (mixture 1). Meanwhile, for Cu, mixture 3 is an ideal ratio to increase the Cu uptake by 14.5%. It shows that both Fe and Cu facilitated each other's uptake in real wastewater conditions. There were also observed minimal toxicity signs such as necrosis throughout the experiment. The appearance of vetiver grass has changed in this experiment starting day 3 and remains yellowish. In conclusion, wastewater that contains a high concentration of Fe than Cu can promise the improvement of both Fe and Cu uptake by vetiver grass. This study benefits researchers that apply phytoremediation to remove heavy metals in wastewater by providing a guideline for Fe and Cu removal by vetiver grass. In future, the study will focus on the mechanism and interaction of Fe and Cu uptake by root

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Effect of organic matter on pathogen population during composting of municipal sludge

2020-12-29 , Hamzah N. , Hashim N.F. , Zainuddin N.S. , Kassim J. , Halip A.A. , Nur Liza Rahim

Population growth in Malaysia is expected to increase rapidly. Every sector of industry is expected to have a revolution including in agriculture sector. The utilization of organic fertilizer in agriculture as a green movement is to replace the chemical fertilizer subsequently, reduce the municipal sludge waste. Hence enhancing the growth and supply of nutrient to plant. However, the pathogenic growth in the final product is the greatest concerns. Thus, this study aims to evaluate the pathogen population in the compost of municipal sludge mixed with landscape waste for 90 days. The pathogen dynamic and its correlation with organic matter in 3 different ratios were analysed and recorded. The result showed that the pathogenic trends was uniformly increased at the early stage of composting and decreased gradually after reached the peak. R4 which comprises of equal ratio between municipal sludge and seed compost showed positive correlation with organic matter. R3 and R4 showed better removal of pathogen at maturity stage. Pseudomonas aeruginosa and Salmonella were failed to comply with the standard for R3 and only Salmonella failed for R4. This study supports the achievement of the Sustainability Development Goal (SDG) as an alternative way to combat the environmental issue by leveraging the usage of the waste produced for the purpose of the waste reduction and sustain the environment.

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Experimental Investigation on the Effectiveness of Truss-Shaped Punching Shear Reinforcement in Flat Slab

2022-07-18 , Shamshinar Salehuddin , Zaini S.S. , Johari M.A.M. , Nur Liza Rahim , Mustaqqim Abdul Rahim

The use of reinforced concrete flat slabs in building construction increases the floor-to-floor clearance, expedites site operations, and offers aesthetically rewarding features. However, punching shear failure in a flat slab is brittle in nature and can be potentially catastrophic. Many studies have been conducted to improve the punching shear capacity of flat slabs but some of the proposed punching shear reinforcements were complicated and costly. This research aimed to evaluate the effectiveness of a simple and cost-effective; truss-shaped punching shear reinforcement embedded in a 1200 mm × 1200 mm × 175 mm thick flat slab specimen. Three types of truss-shaped punching shear reinforcements were prepared. All specimens were supported at the edges and subjected to gravity load tests. The results showed that the introduction of truss-shaped punching shear reinforcement increased the punching shear capacity in the range of 7.71% to 21.47%. The maximum deflection of these specimens exhibited an insignificant increase compared to the control specimen, suggesting that punching failure governed the ultimate behavior. The additional strength offered by truss-shaped punching shear reinforcement makes flat slabs as a construction material more appealing because they allow them to withstand higher design loads.

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Risk of contamination of sturgeon species along the lower Danube with AcIV-E virus from sturgeons raised in aquaculture systems

2023 , Gy Deák , R Matache , R Prangate , G Dumitrescu , E Holban , L Lupea , Nur Liza Rahim , Norlia Mohamad Ibrahim

It is considered that most infections caused by pathogen agents in fish species raised in the closed medium like fishing farms originate from the natural environment, thus there are few information on virus transmission from species raised in aquaculture programs to the wild ones. This issue is important taking into account that the wild sturgeon populations are critically endangerment, and regarding to the IUCN Red List, two of these are already declared extinct. Within Danube Basin, environmental and anthropic factors series (reproduction habitats lost, hydrotechnical works) have caused the sturgeon distribution area to be restricted mainly in the lower segment of the river. In addition, intensive fishing or the introduction of invasive species have produced negative effects and hence the decrease in the population effectiveness. As result, from six native sturgeon species within Danube Basin, in our days, only four are still found. This review shall include an analysis of the status of knowledge, regarding the possible influence which the transmission of some viruses within sNCLDV from aquaculture species to the wild ones, also it shall propose an assessment of the risk of infection within Danube ichthyofaunal.

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Knowledge, attitudes, awareness and practices on household hazardous waste disposal among undergraduate students in Selangor, Malaysia

2022-01-01 , Hamzah N. , Marzuki N.S. , Baharudin F. , Nur Liza Rahim , Mohd Kamil N.A.F. , Akbar N.A. , Mohd Zin N.S.

The exponential growth of population in Malaysia and the consequently growing number of residences have aggravated the problem of household waste. Like many other towns of Selangor, a small town located in every district of Selangor also faces serious problems in terms of household hazardous waste disposal. The households of every district of Selangor generate and discharge a huge amount of untreated hazardous waste daily. In this study, an attempt has been made to analyze the scenario of household hazardous waste disposal in Selangor by means of a Knowledge, Attitude, Awareness and Practices (KAP) survey. Interview and personal observation were used to collect the data. The data collected were tabulated and processed to supplement the analysis through them. This study was using Microsoft Excel to obtain percentage and correlation. The findings show that the average level of knowledge among students was 89.8%. While the average awareness level was 93.7%. The average attitude level for them is 91.8%. Lastly was 44% for practice level. Generally, this paper validates how knowledge influences attitude that subsequently determines behavior particularly in household hazardous waste management as intervened by appropriate environmental education. This study also indicates towards many positive aspects along with the negative ones. The positive aspects are mostly related to the awareness and efforts made by the students, whereas the negative aspects are mostly related to the improper methods of waste disposal adopted by the students and the existing scenario of the disposed waste. It is suggested that the household hazardous disposal practice can be improved by introduce more extensive program in university collaborated with related agencies.

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