Displaying publications 21 - 40 of 161 in total

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  1. Some observations on malaria on rubber estates
    Linnell RMC
    Trans R Soc Trop Med Hyg, 1915;8:238-260.
    Matched MeSH terms: Rubber
  2. Deforestation, forest degradation and readiness of local people of Lubuk Antu, Sarawak for REDD+
    Phua MH, Wong W, Goh MH, Kamlisa Uni Kamlun, Julius Kodoh, Teo S, et al.
    Sains Malaysiana, 2014;43:1461-1470.
    Reducing emissions from deforestation and forest degradation-plus (REDD+) is considered as an important mitigation strategy against global warming. However, the implementation of REDD+ can adversely affect local people who have been practicing shifting cultivation for generations. We analyzed Landsat-5 Thematic Mapper images of 1990 and 2009 to quantifying deforestation and forest degradation at Lubuk Antu District, a typical rural area of Sarawak, Malaysia. The results showed significant loss of intact forest at 0.9% per year, which was substantially higher than the rate of Sarawak. There were increases of oil palm and rubber areas but degraded forest, the second largest land cover type, had increased considerably. The local people were mostly shifting cultivators, who indicated readiness of accepting the REDD+ mechanism if they were given compensation. We estimated the monthly willingness to accept (WTA) at RM462, which can be considered as the opportunity cost of foregoing their existing shifting cultivation. The monthly WTA was well correlated with their monthly household expenses. Instead of cash payment, rubber cultivation scheme was the most preferred form of compensation.
    Matched MeSH terms: Rubber
  3. Effect of electron beam irradiation on natural rubber/linear low density polyethylene blends with m-phenylenebismaleimide
    Nor Hayati Muhammad, Ibrahim Abdullah, Dahlan Mohd
    Sains Malaysiana, 2011;40:1179-1186.
    The effects of HVA-2 on radiation-induced cross-linkings in 60/40 natural rubber/ linear low density polyethylene (NR/LLDPE) blends was studied. NR/LLDPE was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 0 to 250 kGy. Results showed that under the irradiation employed, the blends NR/LLDPE were cross-linked by the electron beam irradiation. The presence of HVA-2 in the blends caused the optimum dose to decrease and the blends to exhibit higher tensile properties. Further, within the dose range studied, the degradation caused by electron beam irradiation was found to be minimal. The optimized processing conditions were 120oC, 50 rpm rotor speed and 13 min processing time. The gel content, tensile strength, elongation at break, hardness and impact test studies were used to follow the irradiation-induced cross-linkings in the blend. For blends of 60/40 NR/LLDPE with 2.0 phr HVA-2, the optimum tensile strength and dose, were 19 MPa and 100 kGy, respectively. Blends of 60/40 NR/LLDPE without HVA-2, the optimum tensile strength and dose were 17.2 MPa and 200 kGy, respectively.
    Matched MeSH terms: Rubber
  4. Mechanical properties of thermoplastic natural rubber (TPNR) reinforced with different types of carbon nanotube
    Tarawneh MA, Sahrim Ahmad, Rozaidi Rasid, Yahya S, Shamsul Bahri A, Ehnoum S, et al.
    Sains Malaysiana, 2011;40:1179-1186.
    The effect of various multi-walled carbon nanotubes (MWNTs) on the tensile properties of thermoplastic natural rubber (TPNR) nanocomposite was investigated. The nanocomposite was prepared using melt blending method. MWNTs were added to improve the mechanical properties of MWNTs/TPNR composites in different compositions of 1, 3, 5, and 7 wt.%. The results showed that the mechanical properties of nanocomposites were affected significantly by the composition and the properties of MWNTs. SEM micrographs confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which was improved mechanical properties significantly.
    Matched MeSH terms: Rubber
  5. Fulltext Brain activation display functional asymmetry in response to action, background and tonal frequency during a pitch memory processing: an fMRI study
    Ahmad Nazlim Yusoff, Khairiah Abdul Hamid, Farah Nabila Ab Rahman, Mazlyfarina Mohamad, Khairiah Abdul Hamid, Siti Zamratol-Mai Sarah Mukari
    Jurnal Sains Kesihatan Malaysia, 2018;16(1):35-44.
    MyJurnal
    In this study, the asymmetry of the main effects of action, background and tonal frequency during a pitch memory processing
    were investigated by means of brain activation. Eighteen participants (mean age 27.6 years) were presented with low and
    high frequency tones in quiet and in noise. They listen, discriminate and recognize the target tone against the final tone
    in a series of four distracting tones. The main effects were studied using the analysis of variance (ANOVA) with action (to
    wring (rubber bulb) vs. not to wring), background (in quiet vs. in noise) and frequency (low vs. high) as the factors (and
    levels respectively). The main effect of action is in the right pre-central gyrus (PCG), in conformation with its contralateral
    behavior. The main effect of background indicated the bilateral primary auditory cortices (PAC) and is right lateralized,
    attributable to white noise. The main effect of frequency is also observed in PAC but bilaterally equal and attributable to
    low frequency tones. Despite the argument that the temporo-spectral lateralization dichotomy is not especially rigid as
    revealed by the main effect of frequency, right lateralization of PAC for the respective main effect of background clearly
    demonstrates its functional asymmetry suggesting different perceptual functionality of the right and left PAC.
    Matched MeSH terms: Rubber
  6. Performance of wet scrubbers to remove VOCs from rubber emissions
    Idris NF, Le-Minh N, Hayes JE, Stuetz RM
    J Environ Manage, 2022 Mar 01;305:114426.
    PMID: 34998062 DOI: 10.1016/j.jenvman.2021.114426
    Poor performance of wet scrubbers in rubber processing plants due to breakthrough of specific volatile organic compounds (VOCs) causes odour impact events. The performance of wet scrubbers in the rubber drying process to remove VOCs was investigated in order to determine the responsible odorants. VOC emissions originating at the inlet and outlet of wet scrubbers were quantified using gas chromatography-mass spectrometry/olfactometry (GC-MS/O). Critical VOCs were identified alongside seasonal and daily variations of those VOCs. Altogether, 80 VOCs were detected in rubber emissions with 16 classified as critical VOCs based on their chemical concentration, high odour activity value (OAV) and unpleasant odour. Volatile fatty acids (VFAs) were the dominant VOCs with seasonal variations affecting emission composition. Results demonstrated the ineffectiveness of the wet scrubbers to mitigate odorous VOCs whereas the removal of some VOCs could be improved based on their polarity and solubility. It was found that there is a correlation between the wet scrubber performance and VFAs concentration in the emissions. The findings demonstrated that combining quantitative and sensory analyses improved accuracy in identifying odorous VOCs, which can cause odour annoyance from rubber processing. A VOC identification framework was proposed using both analyses approaches.
    Matched MeSH terms: Rubber
  7. Fulltext Effects of Carbon Black and the Presence of Static Mechanical Strain on the Swelling of Elastomers in Solvent
    Ch'ng SY, Andriyana A, Tee YL, Verron E
    Materials (Basel), 2015 Mar 02;8(3):884-898.
    PMID: 28787977 DOI: 10.3390/ma8030884
    The effect of carbon black on the mechanical properties of elastomers is of great interest, because the filler is one of principal ingredients for the manufacturing of rubber products. While fillers can be used to enhance the properties of elastomers, including stress-free swelling resistance in solvent, it is widely known that the introduction of fillers yields significant inelastic responses of elastomers under cyclic mechanical loading, such as stress-softening, hysteresis and permanent set. When a filled elastomer is under mechanical deformation, the filler acts as a strain amplifier in the rubber matrix. Since the matrix local strain has a profound effect on the material's ability to absorb solvent, the study of the effect of carbon black content on the swelling characteristics of elastomeric components exposed to solvent in the presence of mechanical deformation is a prerequisite for durability analysis. The aim of this study is to investigate the effect of carbon black content on the swelling of elastomers in solvent in the presence of static mechanical strains: simple extension and simple torsion. Three different types of elastomers are considered: unfilled, filled with 33 phr (parts per hundred) and 66 phr of carbon black. The peculiar role of carbon black on the swelling characteristics of elastomers in solvent in the presence of mechanical strain is explored.
    Matched MeSH terms: Rubber
  8. Divergent accumulation of amino sugars and lignins mediated by soil functional carbon pools under tropical forest conversion
    Li T, Cheng H, Li Y, Mou Z, Zhu X, Wu W, et al.
    Sci Total Environ, 2023 Jul 10;881:163204.
    PMID: 37044342 DOI: 10.1016/j.scitotenv.2023.163204
    Tropical primary forests are being destroyed at an alarming rate and converted for other land uses which is expected to greatly influence soil carbon (C) cycling. However, our understanding of how tropical forest conversions affect the accumulation of compounds in soil functional C pools remains unclear. Here, we collected soils from primary forests (PF), secondary forests (SF), oil-palm (OP), and rubber plantations (RP), and assessed the accumulation of plant- and microbial-derived compounds within soil organic carbon (SOC), particulate (POC) and mineral-associated (MAOC) organic C. PF conversion to RP greatly decreased SOC, POC, and MAOC concentrations, whereas conversion to SF increased POC concentrations and decreased MAOC concentrations, and conversion to OP only increased POC concentrations. PF conversion to RP decreased lignin concentrations and increased amino sugar concentrations in SOC pools which increased the stability of SOC, whereas conversion to SF only increased the lignin concentrations in POC, and conversion to OP just increased lignin concentrations in POC and decreased it in MAOC. We observed divergent dynamics of amino sugars (decrease) and lignin (increase) in SOC with increasing SOC. Only lignin concentrations increased in POC with increasing POC and amino sugars concentrations decreased in MAOC with increasing MAOC. Conversion to RP significantly decreased soil enzyme activities and microbial biomasses. Lignin accumulation was associated with microbial properties, whereas amino sugar accumulation was mainly associated with soil nutrients and stoichiometries. These results suggest that the divergent accumulation of plant- and microbial-derived C in SOC was delivered by the distribution and original composition of functional C pools under forest conversions. Forest conversions changed the formation and stabilization processes of SOC in the long run which was associated with converted plantations and management. The important roles of soil nutrients and stoichiometry also provide a natural-based solution to enhance SOC sequestration via nutrient management in tropical forests.
    Matched MeSH terms: Rubber
  9. Spontaneous Reversibility of an Iatrogenic Orthodontic Elastic Band-induced Localized Periodontitis Following Surgical Intervention - Case Report
    Nettem S, Kumar Nettemu S, Kumar K, Reddy V, Siva Kumar P
    Malays J Med Sci, 2012 Oct;19(4):77-80.
    PMID: 23613652
    Orthodontic elastic bands are an important iatrogenic etiologic factor in the causation of periodontal attachment apparatus breakdown. Appropriate diagnosis and a well constructed treatment plan tailor-made to suit the requirements of the particular patient is imperative for management of periodontal lesions induced by subgingival retention of rubber band. There are conflicting reports regarding the reattachment and regeneration of lost periodontal supporting tissues in such cases. The present case report highlights the spontaneous reversal and correction of periodontal destruction due to iatrogenic orthodontic elastic band displacement deep into the subgingival tissues.
    Matched MeSH terms: Rubber
  10. Preparation and characterization of potato starch nanocrystal reinforced natural rubber nanocomposites
    Rajisha KR, Maria HJ, Pothan LA, Ahmad Z, Thomas S
    Int J Biol Macromol, 2014 Jun;67:147-53.
    PMID: 24657376 DOI: 10.1016/j.ijbiomac.2014.03.013
    Potato starch nanocrystals were found to serve as an effective reinforcing agent for natural rubber (NR). Starch nanocrystals were obtained by the sulfuric acid hydrolysis of potato starch granules. After mixing the latex and the starch nanocrystals, the resulting aqueous suspension was cast into film by solvent evaporation method. The composite samples were successfully prepared by varying filler loadings, using a colloidal suspension of starch nanocrystals and NR latex. The morphology of the nanocomposite prepared was analyzed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM analysis revealed the size and shape of the crystal and their homogeneous dispersion in the composites. The crystallinity of the nanocomposites was studied using XRD analysis which indicated an overall increase in crystallinity with filler content. The mechanical properties of the nanocomposites such as stress-strain behavior, tensile strength, tensile modulus and elongation at break were measured according to ASTM standards. The tensile strength and modulus of the composites were found to improve tremendously with increasing nanocrystal content. This dramatic increase observed can be attributed to the formation of starch nanocrystal network. This network immobilizes the polymer chains leading to an increase in the modulus and other mechanical properties.
    Matched MeSH terms: Rubber/chemistry
  11. Electrolytic treatment of Standard Malaysian Rubber process wastewater
    Vijayaraghavan K, Ahmad D, Yazid AY
    J Hazard Mater, 2008 Jan 31;150(2):351-6.
    PMID: 17543454
    A new method of Standard Malaysian Rubber (SMR) process wastewater treatment was developed based on in situ hypochlorous acid generation. The hypochlorous acid was generated in an undivided electrolytic cell consisting of two sets of graphite as anode and stainless sheets as cathode. The generated hypochlorous acid served as an oxidizing agent to destroy the organic matter present in the SMR wastewater. For an influent COD concentration of 2960 mg/L at an initial pH 4.5+/-0.1, current density 74.5 mA/cm(2), sodium chloride content 3% and electrolysis period of 75 min, resulted in the following residual values pH 7.5, COD 87 mg/L, BOD(5) 60 mg/L, TOC 65 mg/L, total chlorine 146 mg/L, turbidity 7 NTU and temperature 48 degrees C, respectively. In the case of 2% sodium chloride as an electrolyte for the above said operating condition resulted in the following values namely: pH 7.2, COD 165 mg/L, BOD(5) 105 mg/L, TOC 120 mg/L, total chlorine 120 mg/L, turbidity 27 NTU and temperature 53 degrees C, respectively. The energy requirement were found to be 30 and 46 Wh/L, while treating 24 L of SMR wastewater at 2 and 3% sodium chloride concentration at a current density 74.5 mA/cm(2). The observed energy difference was due to the improved conductivity at high sodium chloride content.
    Matched MeSH terms: Rubber/chemistry*
  12. Allergenic proteins of natural rubber latex
    Yeang HY, Arif SA, Yusof F, Sunderasan E
    Methods, 2002 May;27(1):32-45.
    PMID: 12079415 DOI: 10.1016/S1046-2023(02)00049-X
    As the living cytoplasm of laticiferous cells, Hevea brasiliensis latex is a rich blend of organic substances that include a mélange of proteins. A small number of these proteins have given rise to the problem of latex allergy. The salient characteristics of H. brasiliensis latex allergens that are recognized by the International Union of Immunological Societies (IUIS) are reviewed. These are the proteins associated with the rubber particles, the cytosolic C-serum proteins and the B-serum proteins that originate mainly from the lutoids. Procedures for the isolation and purification of latex allergens are discussed, from latex collection in the field to various preparative approaches adopted in the laboratory. As interest in recombinant latex allergens increases, there is a need to validate recombinant proteins to ascertain equivalence with their native counterparts when used in immunological studies, diagnostics, and immunotherapy.
    Matched MeSH terms: Rubber*
  13. The manufacture of gloves from natural rubber latex
    Yip E, Cacioli P
    J Allergy Clin Immunol, 2002 Aug;110(2 Suppl):S3-14.
    PMID: 12170237 DOI: 10.1067/mai.2002.124499
    Gloves that will provide a barrier of protection from infectious organisms are an essential feature of medical practice for the protection of both patients and medical personnel. Natural rubber latex has consistently been the most satisfactory raw material for the manufacture of gloves. Certain latex proteins, carried over into the finished product by inadequate manufacturing processes, may pose a risk of provoking allergic reactions in some patients and medical workers. As with any allergy, the risk depends on the route of exposure and dose. Hence, the method of manufacture, including the means used to coat gloves to make donning easy, can influence the eventual exposure of sensitive people to latex allergens. In this article, we describe the several processes in use and their effects on latex protein content.
    Matched MeSH terms: Rubber*
  14. Identification of three homologous latex-clearing protein (lcp) genes from the genome of Streptomyces sp. strain CFMR 7
    Nanthini J, Ong SY, Sudesh K
    Gene, 2017 Sep 10;628:146-155.
    PMID: 28711667 DOI: 10.1016/j.gene.2017.07.039
    Rubber materials have greatly contributed to human civilization. However, being a polymeric material does not decompose easily, it has caused huge environmental problems. On the other hand, only few bacteria are known to degrade rubber, with studies pertaining them being intensively focusing on the mechanism involved in microbial rubber degradation. The Streptomyces sp. strain CFMR 7, which was previously confirmed to possess rubber-degrading ability, was subjected to whole genome sequencing using the single molecule sequencing technology of the PacBio® RS II system. The genome was further analyzed and compared with previously reported rubber-degrading bacteria in order to identify the potential genes involved in rubber degradation. This led to the interesting discovery of three homologues of latex-clearing protein (Lcp) on the chromosome of this strain, which are probably responsible for rubber degrading activities. Genes encoding oxidoreductase α-subunit (oxiA) and oxidoreductase β-subunit (oxiB) were also found downstream of two lcp genes which are located adjacent to each other. In silico analysis reveals genes that have been identified to be involved in the microbial degradation of rubber in the Streptomyces sp. strain CFMR 7. This is the first whole genome sequence of a clear-zone-forming natural rubber- degrading Streptomyces sp., which harbours three Lcp homologous genes with the presence of oxiA and oxiB genes compared to the previously reported Gordonia polyisoprenivorans strain VH2 (with two Lcp homologous genes) and Nocardia nova SH22a (with only one Lcp gene).
    Matched MeSH terms: Rubber/metabolism
  15. Fulltext Thermal Stability and Rheological Properties of Epoxidized Natural Rubber-Based Magnetorheological Elastomer
    Yunus NA, Mazlan SA, Ubaidillah, Abdul Aziz SA, Tan Shilan S, Abdul Wahab NA
    Int J Mol Sci, 2019 Feb 10;20(3).
    PMID: 30744210 DOI: 10.3390/ijms20030746
    Determination of the thermal characteristics and temperature-dependent rheological properties of the magnetorheological elastomers (MREs) is of paramount importance particularly with regards to MRE applications. Hitherto, a paucity of temperature dependent analysis has been conducted by MRE researchers. In this study, an investigation on the thermal and rheological properties of epoxidized natural rubber (ENR)-based MREs was performed. Various percentages of carbonyl iron particles (CIPs) were blended with the ENR compound using a two roll-mill for the preparation of the ENR-based MRE samples. The morphological, elemental, and thermal analyses were performed before the rheological test. Several characterizations, as well as the effects of the strain amplitude, temperature, and magnetic field on the rheological properties of ENR-based MRE samples, were evaluated. The micrographs and elemental results were well-correlated regarding the CIP and Fe contents, and a uniform distribution of CIPs was achieved. The results of the thermal test indicated that the incorporation of CIPs enhanced the thermal stability of the ENR-based MREs. Based on the rheological analysis, the storage modulus and loss factor were dependent on the CIP content and strain amplitude. The effect of temperature on the rheological properties revealed that the stiffness of the ENR-based MREs was considered stable, and they were appropriate to be employed in the MRE devices exposed to high temperatures above 45 °C.
    Matched MeSH terms: Rubber/chemistry*
  16. Fulltext Properties Of Sulphur In Colloidal System: A Review
    Nuriah Mohamad, Azlin Suhaida Azmi, Fathilah Ali, Mohamad Firdaus Omar
    Biological and Natural Resources Engineering Journal, 2019;2(2):13-20.
    MyJurnal
    Sulfur has been highly sought by many industries everywhere around the world for various applications. This exceptionally useful element has been largely manufactured especially in powder form each year reflecting its increase in demand in line with technological advancement and uses for various product applications. The manufacturing processes include mining as well as chemical reactions in Claus Process. Rubber industries normally use abundance of sulfur in their latex compound to introduce vulcanization. The geneal concern of sulfur for rubber vulcanization is dispersibility in the rubber matrix due to improper optimization of its preparation process prior to latex compounding. Another crucial issue is crystallization of soluble sulfur from its insoluble origin, either during or post-rubber vulcanization that constitutes to formation of sulfur bloom that grows on the surface of the rubber articles. It is known that both issues are related to the process conditions and compounding recipe that could not be fully solved. Various studies have been conducted to minimize such occurences – from process optimization to sulfur chemistry itself – and of continuous improvement and innovation to solve various threats in sulfur applications. This paper reviews on detailed description on elemental sulfur, of respective industrial applications, and most importantly highlights on sulfur trends and issues normally encountered.
    Matched MeSH terms: Rubber
  17. Fulltext Enhanced mechanical and thermal properties of electrically conductive TPNR/GNP nanocomposites assisted with ultrasonication
    Chen RS, Mohd Ruf MFH, Shahdan D, Ahmad S
    PLoS One, 2019;14(9):e0222662.
    PMID: 31545820 DOI: 10.1371/journal.pone.0222662
    Thermoplastic natural rubber (TPNR) was compounded with graphene nanoplatelets (GNP) via ultrasonication and melt blending. The effects of ultrasonication period (1-4 hours) and GNP weight fraction (0.5, 1.0, 1.5 and 2.0 wt.%) on the mechanical, thermal and conductivity properties were investigated. Results showed that the 3 hours of ultrasonic treatment on LNR/GNP gave the greatest improvement in tensile strength of 25.8% (TPNR/GNP nanocomposites) as compared to those without ultrasonication. The TPNR nanocomposites containing 1.5 wt.% GNP exhibited the highest strength (16 MPa for tensile, 14 MPa for flexural and 11 kJm-2 for impact) and modulus (556 MPa and 869 MPa for tensile and flexural, respectively). The incorporation of GNP had enhanced the thermal stability. It can be concluded that the GNP had imparted the thermally and electrically conductive nature to the TPNR blend.
    Matched MeSH terms: Rubber
  18. Low-Cost Self-Made Arthroscopic Training Camera Is Equally as Effective as Commercial Camera: A Comparison Study
    Ling JL, Teo SH, Mohamed Al-Fayyadh MZ, Mohamed Ali MR, Ng WM
    Arthroscopy, 2019 02;35(2):596-604.
    PMID: 30611592 DOI: 10.1016/j.arthro.2018.08.038
    PURPOSE: To assess the effectiveness of a low-cost self-made arthroscopic camera (LAC) in basic arthroscopic skills training compared with a commercial arthroscopic camera (CAC).

    METHODS: One hundred fifty-three orthopaedic residents were recruited and randomly assigned to either the LAC or CAC. They were allocated 2 practice sessions, with 20 minutes each, to practice 4 given arthroscopic tasks: task 1, transferring objects; task 2, stacking objects; task 3, probing numbers; and task 4, stretching rubber bands. The time taken for participants to complete the given tasks was recorded in 3 separate tests; before practice, immediately after practice, and after a period of 3 months. A comparison of the time taken between both groups to complete the given tasks in each test was measured as the primary outcome.

    RESULTS: Significant improvements in time completion were seen in the post-practice test for both groups in all given arthroscopic tasks, each with P < .001. However, there was no significant difference between the groups for task 1 (P = .743), task 2 (P = .940), task 3 (P = .932), task 4 (P = .929), and total (P = .944). The outcomes of the tests (before practice, after practice, and at 3 months) according to repeated measures analysis of variance did not differ significantly between the groups in task 1 (P = .475), task 2 (P = .558), task 3 (P = .850), task 4 (P = .965), and total (P = .865).

    CONCLUSIONS: The LAC is equally as effective as the CAC in basic arthroscopic skills training with the advantage of being cost-effective.

    CLINICAL RELEVANCE: In view of the scarcity in commercial arthroscopic devices for trainees, this low-cost device, which trainees can personally own and use, may provide a less expensive and easily available way for trainees to improve their arthroscopic skills. This might also cultivate more interest in arthroscopic surgery among junior surgeons.

    Matched MeSH terms: Rubber
  19. Fulltext Seismic response of a base isolated cable-stayed bridge under near-fault ground motion excitations
    Ahad Javanmardi, Zainab Ibrahim, Khaled Gheadi, Mohammed Jameel, Usman Hanif, Gordan, Meisam
    Scientific Research Journal, 2018;15(1):1-14.
    MyJurnal
    Nowadays, development of cable-stayed bridges is increasing around the world. The mitigation of seismic forces to these bridges are obligatory to prevent damages or failure of its structural members. Herein, this paper aimed to determine the near-fault ground motion effect on an existing cablestayed bridge equipped with lead-rubber bearing. In this context, Shipshaw cable-stayed bridge is selected as the case study. The selected bridge has a span of 183.2 m composite deck and 43 m height of steel tower. 2D finite element models of the non-isolated and base isolated bridges are modelled by using SAP2000. Three different near-fault ground motions which are Tabas 1978, Cape Mendocino 1992 and Kobe 1995 were subjected to the 2D FEM models in order to determine the seismic behaviour of the bridge. The near-fault ground motions were applied to the bridge in the longitudinal direction. Nonlinear dynamic analysis was performed to determine the dynamic responses of the bridge. Comparison of dynamic response of nonisolated and base isolated bridge under three different near-fault ground motions were conducted. The results obtained from numerical analyses of the bridge showed that the isolation system lengthened the period of bridge and minimised deck displacement, base shear and base moment of the bridge. It is concluded that the isolation system significantly reduced the destructive effects of near-fault ground motions on the bridge.
    Matched MeSH terms: Rubber
  20. Fulltext Deformation Properties of Rubberized ECC Incorporating Nano Graphene Using Response Surface Methodology
    Hau Hong DL, Mohammed BS, Al-Fakih A, Wahab MMA, Liew MS, Amran YHM
    Materials (Basel), 2020 Jun 24;13(12).
    PMID: 32599798 DOI: 10.3390/ma13122831
    Engineered cementitious composite (ECC) was discovered as a new substitute of conventional concrete as it provides better results in terms of tensile strain, reaching beyond 3%. From then, more studies were done to partially replace crumb rubber with sand to achieve a more sustainable and eco-friendlier composite from the original ECC. However, the elastic modulus of ECC was noticeably degraded. This could bring potential unseen dangerous consequences as the fatigue might happen at any time without any sign. The replacement of crumb rubber was then found to not only bring a more sustainable and eco-friendlier result but also increase the ductility and the durability of the composite, with lighter specific gravity compared to conventional concrete. This study investigated the effects of crumb rubber (CR) and graphene oxide (GO) toward the deformable properties of rubberized ECC, including the compressive strength, elastic modulus, Poisson's ratio, and drying shrinkage. Central composite design (CCD) was utilized to provide 13 reasonable trial mixtures with the ranging level of CR replacement from 0-30% and that of GO from 0.01-0.08%. The results show that GO increased the strength of the developed GO-RECC. It was also found that the addition of CR and GO to ECC brought a notable improvement in mechanical and deformable properties. The predicted model that was developed using response surface methodology (RSM) shows that the variables (compression strength, elastic modulus, Poisson's ratio, and drying shrinkage) rely on the independent (CR and GO) variables and are highly correlated.
    Matched MeSH terms: Rubber
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