Displaying publications 61 - 80 of 161 in total

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  1. Bokhari A, Yusup S, Chuah LF, Klemeš JJ, Asif S, Ali B, et al.
    Bioresour Technol, 2017 Oct;242:272-282.
    PMID: 28341378 DOI: 10.1016/j.biortech.2017.03.046
    Chemical interesterification of rubber seed oil has been investigated for four different designed orifice devices in a pilot scale hydrodynamic cavitation (HC) system. Upstream pressure within 1-3.5bar induced cavities to intensify the process. An optimal orifice plate geometry was considered as plate with 1mm dia hole having 21 holes at 3bar inlet pressure. The optimisation results of interesterification were revealed by response surface methodology; methyl acetate to oil molar ratio of 14:1, catalyst amount of 0.75wt.% and reaction time of 20min at 50°C. HC is compared to mechanical stirring (MS) at optimised values. The reaction rate constant and the frequency factor of HC were 3.4-fold shorter and 3.2-fold higher than MS. The interesterified product was characterised by following EN 14214 and ASTM D 6751 international standards.
    Matched MeSH terms: Rubber
  2. Al-Mansob RA, Ismail A, Yusoff NI, Rahmat RA, Borhan MN, Albrka SI, et al.
    PLoS One, 2017;12(2):e0171648.
    PMID: 28182724 DOI: 10.1371/journal.pone.0171648
    Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.
    Matched MeSH terms: Rubber/chemistry*
  3. Shahrol Mohamaddan, Chai Siew Fu, Ahmad Hata Rasit, Siti Zawiah Md Dawal, Keith Case
    MyJurnal
    Congenital talipes equinovarus (CTEV) or clubfoot is a complex deformity of the foot that is characterised by four main deformities; forefoot cavus and adductus, hindfoot varus and ankle equinus. Currently, the Ponseti method is the most general and recognized treatment with a high success rate of over 90%. The treatment involves gentle manipulation and serial casting. However, the casting method could create complications for the patients such as soft-tissue damage and inconvenience in following the treatment schedule especially for those living far away from hospital. The aim of this research is to develop an adjustable corrective device for clubfoot treatment based on the techniques in the Ponseti method and at the same time attempt to eliminate the side-effects. The prototype consists of six adjustable movements from six different mechanisms to correct the four deformities. The prototype was developed using 3D printing method and the main material used is polylactic acid (PLA), rubber, aluminium and cotton fabric with sponge. The total weight of the prototype is around 300 g.
    Matched MeSH terms: Rubber
  4. Sofian Ibrahim, Chantara Thevy Ratnam, Chai, Chee Keong, Noor Hasni M. Ali, Mohd Noorwadi Mat Lazim, Khairiah Badri
    MyJurnal
    Peroxide pre-vulcanized natural rubber latex prepared by using gamma irradiation technique is an alternative over the conventionally prepared peroxide pre-vulcanized that used activator to promote the peroxide decomposition in natural rubber latex. Through this technique the problems aroused by some activators such as tends to darken the natural rubber latex film during the drying process can also be overcome. For this preliminary study, data obtained from crosslink density and mechanical measurements were used to evaluate the effectiveness of gamma irradiation in the vulcanization process. Increasing the quantity of tert-butyl hydroperoxide (t-BHPO) from 0.1 pphr to 0.3 pphr while the irradiation dose maintain at 12 kGy has successfully delivered peroxide vulcanized natural rubber latex films with average tensile strength, modulus @ 500% and modulus @ 700% around 15.33, 1.01 and 3.42 MPa, respectively. The effective pre-vulcanization irradiation dose with respect to maximum crosslinking density (85.8 %) was observed on film prepared at 0.1 pphr t-BHPO.
    Matched MeSH terms: Rubber
  5. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
    Matched MeSH terms: Rubber
  6. Suzy Aziziyana Saili, Rosila Bee Mohd Hussain, Khairulnizam Mat Karim
    MyJurnal
    A plural society existence due to economic policy is an outcome of foreign colonization. Due to the
    British economic policy, Malaya saw the influx two foreign ethnic; Chinese and Indian, working in tin
    mining and rubber estates respectively. Early conflict involving the Malays and these foreign workers
    is inevitable which is evident during both the Japanese intervention and the British colonization. The
    objective of this paper is to review the role and responsibilities of Communities Liaison Committee in
    pioneering social cohesion between the three main ethnics in Malaya during the crucial time of
    Japanese intervention, British colonization, communist threat and the declaration of emergency. Before
    CLC, a cooperation was initiated by AMCJA-PUTERA coalition but was short lived due to the absence
    of support from the British and lack of bargaining between Malays and Non-Malays. CLC received a
    full patronage of the British as the pioneer of social cohesion in Malaya, especially when it was able to call upon the three main ethnic in its discussion of bargaining and negotiation or what is widely known
    as the social contract, as well as practicing political power sharing.
    Matched MeSH terms: Rubber
  7. Mat Uzir Wahi, Azman Hassan, Akos Noel Ibrahim, Nurhayati Ahmad Zawawi, Kunasegeran K
    Sains Malaysiana, 2015;44:1615-1623.
    Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection
    molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical
    resistance and water absorption properties of the blends were studied using standard methods. The toughness of the
    blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical
    properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size
    as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in
    crystallization temperature (Tc
    ) as ENR content increases while the glass transition temperature (Tg
    ) remained unchanged.
    Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the
    chemical resistance of the blends.
    Matched MeSH terms: Rubber
  8. Abu Bakar, M.A., Ahmad, S., Kuntjoro, W.
    MyJurnal
    Kenaf fibre that is known as Hibiscus cannabinus, L. family Malvaceae is an herbaceous plant that can be grown under a wide range of weather conditions. The uses of kenaf fibres as a reinforcement material in the polymeric matrix have been widely investigated. It is known that epoxy has a disadvantage of brittleness and exhibits low toughness. In this research, liquid epoxidized natural rubber (LENR) was introduced to the epoxy to increase its toughness. Kenaf fibres, with five different fibre loadings of 5%, 10%, 15%, 20% and 25% by weight, were used to reinforce the epoxy resins (with and without addition of epoxidized natural rubber) as the matrices. The flexural strength, flexural modulus and fracture toughness of the rubber toughened epoxy reinforced kenaf fibre composites were investigated. The results showed that the addition of liquid epoxidized natural rubber (LENR) had improved the flexural modulus, flexural strength and fracture toughness by 48%, 30%, and 1.15% respectively at 20% fibre loading. The fractured surfaces of these composites were investigated by using scanning electron microscopic (SEM) technique to determine the interfacial bonding between the matrix and the fibre reinforcement.
    Matched MeSH terms: Rubber
  9. Khor GL, Yusof AM, Tee ES, Kandiah M, Lee Huang MS
    Asia Pac J Clin Nutr, 1999 Dec;8(4):272-9.
    PMID: 24394228
    Assessment of the nutritional status of 4054 households from rural communities in Peninsular Malaysia was undertaken from 1992 to 1995. Body mass index (BMI) and waist-to-hip ratio (WHR) were obtained from a self-selected sample of 1854 men and 2741 women aged >= 18 years. The BMI and WHR results are presented according to gender, age groups and type of community as defined by the main occupation, namely, fishing, rice farming, estate work, rubber and coconut small-holding. The mean BMI for men and women of all age groups are 22.5 kg/m2 and 23.8 kg/m2, respectively. The mean BMI for both genders increases with age between 18.0 and 49.9 years, after which the value declines. The prevalence of pre-obese (BMI >= 25.0-29.9 kg/m2) is 19.8% for men and 28.0% for women. The prevalence of obese men and women (>= 30.0 kg/m2) is 4.2% and 11.1%, respectively. The highest prevalence of pre-obese and obese men is found in the age groups of 30.0-49.9 years, while that for women is in the 40.0-49.9 years age group. The prevalence of pre-obesity and obesity is higher in women than in men for every age group. A similar result was indicated by WHR whereby a higher proportion of women (22.5%) than men (5%) for all ages was found to show central obesity. The prevalence of overweight adults is higher when compared with previous studies on subjects from almost similar rural communities. This study indicated that overweight is on the increase in rural communities, especially among female subjects.
    Matched MeSH terms: Rubber
  10. 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
  11. Zahari R, Halimoon N, Ahmad MF, Ling SK
    Int J Anal Chem, 2018;2018:8150610.
    PMID: 29692811 DOI: 10.1155/2018/8150610
    Rigidoporus microporus, Ganoderma philippii, and Phellinus noxius are root rot rubber diseases and these fungi should be kept under control with environmentally safe compounds from the plant sources. Thus, an antifungal compound isolated from Catharanthus roseus was screened for its effectiveness in controlling the growth of these fungi. The antifungal compound isolated from C. roseus extract was determined through thin layer chromatography (TLC) and nuclear magnetic resonance (NMR) analysis. Each C. roseus of the DCM extracts was marked as CRD1, CRD2, CRD3, CRD4, CRD5, CRD6, and CRD7, respectively. TLC results showed that all of the C. roseus extracts peaked with red colour at Rf = 0.61 at 366 nm wavelength, except for CRD7. The CRD4 extract was found to be the most effective against R. microporus and G. philippii with inhibition zones of 3.5 and 1.9 mm, respectively, compared to that of other extracts. These extracts, however, were not effective against P. noxius. The CRD4 extract contained ursolic acid that was detected by NMR analysis and the compound could be developed as a biocontrol agent for controlling R. microporus and G. philippii. Moreover, little or no research has been done to study the effectiveness of C. roseus in controlling these fungi.
    Matched MeSH terms: Rubber
  12. Linnell RMC
    Trans R Soc Trop Med Hyg, 1915;8:238-260.
    Matched MeSH terms: Rubber
  13. 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
  14. Kunaparaju K, Shetty K, Jathanna V, Nath K, M R
    Patient Saf Surg, 2021 Jan 05;15(1):1.
    PMID: 33402200 DOI: 10.1186/s13037-020-00273-3
    BACKGROUND: Accidental ingestion of a dental bur during the dental procedure is a rare, but a potentially serious complication. Early recognition and foreign body retrieval is essential to prevent adverse patient outcomes.

    CASE PRESENTATION: A 76-year old male patient, presented to the department with a chief complaint of sensitivity in his upper right back tooth due to attrition. After assessing the pulp status, root canal therapy was planned for the tooth. During the procedure, it was noticed that the dental bur slipped out of the hand piece and the patient had accidentally ingested it. The patient was conscious and had no trouble while breathing at the time of ingestion of the bur although he had mild cough which lasted for a short duration. The dental procedure was aborted immediately and the patient was taken to the hospital for emergency care. The presence and location of the dental bur was confirmed using chest and abdominal x-rays and it was subsequently retrieved by esophagogastroduodenoscopy (EGD) procedure under general anaesthesia on the same day as a part of the emergency procedure. The analysis of this case reaffirms the importance of the use of physical barriers such as rubber dams and gauze screens as precautionary measures to prevent such incidents from occurring.

    CONCLUSION: Ingestion of instruments are uncertain and hazardous complications to encounter during a dental procedure. The need for physical barrier like rubber dam is mandatory for all dental procedures. However, the dentist should be well trained to handle such medical emergencies and reassure the patient by taking them into confidence. Each incident encountered should be thoroughly documented to supply adequate guidance for treatment aspects. This would fulfil the professional responsibilities of the dentist/ clinician and may help avoid possible legal and ethical issues. This case report emphasizes on the need for the usage of physical barriers during dental procedures in order to avoid medical emergencies.

    Matched MeSH terms: Rubber Dams
  15. Dazylah Darji, Ma'zam Md Said
    MyJurnal
    Epoxidised Natural Rubber (ENR) is now a commercially available polymer produced by chemical modification of natural rubber. Currently, three types of ENR are commercially available, and these are ENR 10, ENR 25, and ENR 50 with 10%, 25%, and 50% mol epoxidation, respectively. Studies on prevulcanisation of ENR 50 and postvulcanisation of the latex films were carried out. The objective of this study was to develop ENR 50 that could be dipped easily in coagulant dipping solution to produce dipped products. Several attempts were made by compounding prevulcanised ENR 50 at various sulphur levels ranging from 0.5 to 3.0 pphr. Using suitable coagulant dipping systems, ENR 50 film could be formed despite the high contents of non-ionic surfactant. It was found that the tensile strength of prevulcanised ENR 50 film decreased with the increase in the sulphur level. The results show that as level of sulphur increased, M300 also increased to an optimum value of 1.5 pphr of sulphur. For the postvulcanised ENR 50 film, however, the tensile strength increased and then decreased with the increasing sulphur level. Meanwhile M300 increased with the increasing postvulcanization time and sulphur level. The postvulcanisation of ENR 50 film seems to be a more effective way of increasing tensile properties than by prevulcanisation of ENR 50.
    Matched MeSH terms: Rubber
  16. Dahlan Mohd, Mahathir Mohamed
    MyJurnal
    Polymer blends of 60/40 NR/HDPE were prepared using Brabender PL2000 Plasticorder with 60g capacity. The blends were added with radiation-sensitive natural rubber (NR)-based compatibilizer, known as LENRA. They were irradiated with electron-beam radiation at various doses. The efficacy of the compatibilizer was monitored by measuring various properties of the blends such as physical and dynamic mechanical properties including morphological studies by electron microscopic technique. Early results show that the addition of LENRA improves the properties of the TPNR blends.
    Matched MeSH terms: Rubber
  17. Alkarkhi AFM, Amr SSA, Alqaraghuli WAA, Özdemir Y, Zulkifli M, Mahmud MN
    Data Brief, 2021 Feb;34:106685.
    PMID: 33409347 DOI: 10.1016/j.dib.2020.106685
    This article provides data regarding the performance of zinc sulphate as a coagulant for treating rubber industry wastewater. The effect of four factors on removal efficiency of nine parameters is investigated, namely: pH, mixing speed, dosage of coagulant (zinc sulphate) and retention time. Response surface methodology was used to investigate the effect of selected variables. The data obtained from face centered composite design (FCCD) were analyzed by using analysis of variance (ANOVA) and regression model to find the optimum operating conditions for the selected factors.
    Matched MeSH terms: Rubber
  18. Ibrahim MR, Katman HY, Karim MR, Koting S, Mashaan NS
    ScientificWorldJournal, 2014;2014:240786.
    PMID: 24574875 DOI: 10.1155/2014/240786
    The main objective of this paper is to investigate the relations of rubber size, rubber content, and binder content in determination of optimum binder content for open graded friction course (OGFC). Mix gradation type B as specified in Specification for Porous Asphalt produced by the Road Engineering Association of Malaysia (REAM) was used in this study. Marshall specimens were prepared with four different sizes of rubber, namely, 20 mesh size [0.841 mm], 40 mesh [0.42 mm], 80 mesh [0.177 mm], and 100 mesh [0.149 mm] with different concentrations of rubberised bitumen (4%, 8%, and 12%) and different percentages of binder content (4%-7%). The appropriate optimum binder content is then selected according to the results of the air voids, binder draindown, and abrasion loss test. Test results found that crumb rubber particle size can affect the optimum binder content for OGFC.
    Matched MeSH terms: Rubber/chemistry*
  19. Lau NS, Makita Y, Kawashima M, Taylor TD, Kondo S, Othman AS, et al.
    Sci Rep, 2016 06 24;6:28594.
    PMID: 27339202 DOI: 10.1038/srep28594
    Hevea brasiliensis Muell. Arg, a member of the family Euphorbiaceae, is the sole natural resource exploited for commercial production of high-quality natural rubber. The properties of natural rubber latex are almost irreplaceable by synthetic counterparts for many industrial applications. A paucity of knowledge on the molecular mechanisms of rubber biosynthesis in high yield traits still persists. Here we report the comprehensive genome-wide analysis of the widely planted H. brasiliensis clone, RRIM 600. The genome was assembled based on ~155-fold combined coverage with Illumina and PacBio sequence data and has a total length of 1.55 Gb with 72.5% comprising repetitive DNA sequences. A total of 84,440 high-confidence protein-coding genes were predicted. Comparative genomic analysis revealed strong synteny between H. brasiliensis and other Euphorbiaceae genomes. Our data suggest that H. brasiliensis's capacity to produce high levels of latex can be attributed to the expansion of rubber biosynthesis-related genes in its genome and the high expression of these genes in latex. Using cap analysis gene expression data, we illustrate the tissue-specific transcription profiles of rubber biosynthesis-related genes, revealing alternative means of transcriptional regulation. Our study adds to the understanding of H. brasiliensis biology and provides valuable genomic resources for future agronomic-related improvement of the rubber tree.
    Matched MeSH terms: Rubber/metabolism*
  20. Makita Y, Ng KK, Veera Singham G, Kawashima M, Hirakawa H, Sato S, et al.
    DNA Res, 2017 Apr 01;24(2):159-167.
    PMID: 28431015 DOI: 10.1093/dnares/dsw056
    Natural rubber has unique physical properties that cannot be replaced by products from other latex-producing plants or petrochemically produced synthetic rubbers. Rubber from Hevea brasiliensis is the main commercial source for this natural rubber that has a cis-polyisoprene configuration. For sustainable production of enough rubber to meet demand elucidation of the molecular mechanisms involved in the production of latex is vital. To this end, we firstly constructed rubber full-length cDNA libraries of RRIM 600 cultivar and sequenced around 20,000 clones by the Sanger method and over 15,000 contigs by Illumina sequencer. With these data, we updated around 5,500 gene structures and newly annotated around 9,500 transcription start sites. Second, to elucidate the rubber biosynthetic pathways and their transcriptional regulation, we carried out tissue- and cultivar-specific RNA-Seq analysis. By using our recently published genome sequence, we confirmed the expression patterns of the rubber biosynthetic genes. Our data suggest that the cytoplasmic mevalonate (MVA) pathway is the main route for isoprenoid biosynthesis in latex production. In addition to the well-studied polymerization factors, we suggest that rubber elongation factor 8 (REF8) is a candidate factor in cis-polyisoprene biosynthesis. We have also identified 39 transcription factors that may be key regulators in latex production. Expression profile analysis using two additional cultivars, RRIM 901 and PB 350, via an RNA-Seq approach revealed possible expression differences between a high latex-yielding cultivar and a disease-resistant cultivar.
    Matched MeSH terms: Rubber/metabolism*
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