Displaying publications 1 - 20 of 91 in total

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  1. Zulkifli FH, Hussain FSJ, Harun WSW, Yusoff MM
    Int J Biol Macromol, 2019 Feb 01;122:562-571.
    PMID: 30365990 DOI: 10.1016/j.ijbiomac.2018.10.156
    This study is focusing to develop a porous biocompatible scaffold using hydroxyethyl cellulose (HEC) and poly (vinyl alcohol) (PVA) with improved cellular adhesion profiles and stability. The combination of HEC and PVA were synthesized using freeze-drying technique and characterized using SEM, ATR-FTIR, TGA, DSC, and UTM. Pore size of HEC/PVA (2-40 μm) scaffolds showed diameter in a range of both pure HEC (2-20 μm) and PVA (14-70 μm). All scaffolds revealed high porosity above 85%. The water uptake of HEC was controlled by PVA cooperation in the polymer matrix. After 7 days, all blended scaffolds showed low degradation rate with the increased of PVA composition. The FTIR and TGA results explicit possible chemical interactions and mass loss of blended scaffolds, respectively. The Tg values of DSC curved in range of HEC and PVA represented the miscibility of HEC/PVA blend polymers. Higher Young's modulus was obtained with the increasing of HEC value. Cell-scaffolds interaction demonstrated that human fibroblast (hFB) cells adhered to polymer matrices with better cell proliferation observed after 7 days of cultivation. These results suggested that biocompatible of HEC/PVA scaffolds fabricated by freeze-drying method might be suitable for skin tissue engineering applications.
    Matched MeSH terms: Mechanical Phenomena
  2. Zainal MA, Ahmad A, Mohamed Ali MS
    Biomed Microdevices, 2017 Mar;19(1):8.
    PMID: 28124762 DOI: 10.1007/s10544-017-0148-5
    This paper reports the wireless Shape-Memory-Polymer actuator operated by external radio frequency magnetic fields and its application in a drug delivery device. The actuator is driven by a frequency-sensitive wireless resonant heater which is bonded directly to the Shape-Memory-Polymer and is activated only when the field frequency is tuned to the resonant frequency of heater. The heater is fabricated using a double-sided Cu-clad Polyimide with much simpler fabrication steps compared to previously reported methods. The actuation range of 140 μm as the tip opening distance is achieved at device temperature 44 °C in 30 s using 0.05 W RF power. A repeatability test shows that the actuator's average maximum displacement is 110 μm and standard deviation of 12 μm. An experiment is conducted to demonstrate drug release with 5 μL of an acidic solution loaded in the reservoir and the device is immersed in DI water. The actuator is successfully operated in water through wireless activation. The acidic solution is released and diffused in water with an average release rate of 0.172 μL/min.
    Matched MeSH terms: Mechanical Phenomena*
  3. Yusof MFM, Hamid PNKA, Tajuddin AA, Hashim R, Bauk S, Isa NM, et al.
    Radiol Phys Technol, 2017 Sep;10(3):331-339.
    PMID: 28718054 DOI: 10.1007/s12194-017-0408-3
    The aim of this study was to determine the suitability of tannin-added Rhizophora spp. particleboards as phantom materials in the application of low- and high-energy photons. The tannin-added Rhizophora spp. particleboards and density plug phantoms were created with a target density of 1.0 g/cm3. The elemental composition and effective atomic number of the particleboards were measured using energy dispersive X-ray analysis. The mass attenuation coefficient of the particleboards for low-energy photons were measured using the attenuation of X-ray fluorescence. The mass attenuation coefficients of high-energy photons were measured using the attenuation of 137Cs and 60Co gamma energies. The results were compared to the calculated value of water using XCOM calculations. The results showed that the effective atomic number and mass attenuation coefficients of tannin-added Rhizophora spp. particleboards were similar to those of water, indicating the suitability of tannin-added Rhizophora spp. particleboards as phantom materials for low- and high-energy photons.
    Matched MeSH terms: Mechanical Phenomena
  4. 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: Mechanical Phenomena
  5. Yu L, Mei Q, Xiang L, Liu W, Mohamad NI, István B, et al.
    Front Bioeng Biotechnol, 2021;9:629809.
    PMID: 33842444 DOI: 10.3389/fbioe.2021.629809
    Ground reaction force (GRF) is a key metric in biomechanical research, including parameters of loading rate (LR), first impact peak, second impact peak, and transient between first and second impact peaks in heel strike runners. The GRFs vary over time during stance. This study was aimed to investigate the variances of GRFs in rearfoot striking runners across incremental speeds. Thirty female and male runners joined the running tests on the instrumented treadmill with speeds of 2.7, 3.0, 3.3, and 3.7 m/s. The discrete parameters of vertical average loading rate in the current study are consistent with the literature findings. The principal component analysis was modeled to investigate the main variances (95%) in the GRFs over stance. The females varied in the magnitude of braking and propulsive forces (PC1, 84.93%), whereas the male runners varied in the timing of propulsion (PC1, 53.38%). The female runners dominantly varied in the transient between the first and second peaks of vertical GRF (PC1, 36.52%) and LR (PC2, 33.76%), whereas the males variated in the LR and second peak of vertical GRF (PC1, 78.69%). Knowledge reported in the current study suggested the difference of the magnitude and patterns of GRF between male and female runners across different speeds. These findings may have implications for the prevention of sex-specific running-related injuries and could be integrated with wearable signals for the in-field prediction and estimation of impact loadings and GRFs.
    Matched MeSH terms: Biomechanical Phenomena; Mechanical Phenomena
  6. Ying Wang, Yonghui Chen, Zhenhua Hu, Qiang Feng, Desen Kong
    Sains Malaysiana, 2017;46:2231-2239.
    Ground improvement using artificial crust composite foundation, consisting of stabilization of soft clay and composite foundation, is an effective technique for the treatment of deep soft soil layers under infrastructure embankments. In this study, the load responses and settlement performance of this improvement technique were investigated using two centrifuge model tests to compare the variations of the vertical deformation, pore water pressure, axial force of the piles and tensile stress at the bottom of the artificial crust in the crust composite foundation with those in pile-supported embankment. The results of centrifuge model tests showed that the load responses and settlement performance of artificial crust composite foundation was different from the pile-supported embankment, which displayed mainly that the final middle settlement of crust composite foundation can be reduced by about 15% compared with those of pile-supported embankment with the same length of pile and construction cost. The deformation of the crust with the characteristics of the plate was found based on the change of the tensile stress. Additionally, the excess pore water pressure in the crust composite foundation was lower owing to the stress diffusion effect of the crust during the loading period and the dissipation rate of excess pore water pressure was slower due to lower permeability of the crust at the same loading period. Eventually, the axial force of the middle piles was reduced. At the same time, the boundary stress was functioned with the crust, the axial force of the side piles was improved. The comparison of measured and calculated results was carried out using the stress reduction ratio, the result shows that the bearing capacity of the subsoil in the crust composite was improved.
    Matched MeSH terms: Mechanical Phenomena
  7. Yeoh SY, Lubowa M, Tan TC, Murad M, Mat Easa A
    Food Chem, 2020 Dec 15;333:127425.
    PMID: 32683254 DOI: 10.1016/j.foodchem.2020.127425
    Zero-salted yellow alkaline noodles (YAN) were immersed in solutions of resistant starch HYLON™ VII (HC) or fruit coating Semperfresh™ (SC) containing a range of salt (NaCl) between 10 and 30% (w/v). The objective was to evaluate the effect of salt-coatings on the textural, handling, cooking, and sensory properties of YAN. Increasing salt in the coatings caused a reduction in optimum cooking time, cooking loss and increase in cooking yield. The mechanical and textural parameters, sensory hardness, springiness and overall sensory acceptability of the salt-coated noodles however decreased with increasing salt application. HC-Na10 and SC-Na10 showed the highest textural and mechanical parameters, sensory hardness and springiness. The differences in the parameters were attributed mainly to the water absorption properties of starch that was affected by salt application. Thus, the quality of salt-coated noodles was dependent mainly on the amounts of salt applied in the coatings rather than on the types of coatings used.
    Matched MeSH terms: Mechanical Phenomena*
  8. Uwamahoro R, Sundaraj K, Subramaniam ID
    Biomed Eng Online, 2021 Jan 03;20(1):1.
    PMID: 33390158 DOI: 10.1186/s12938-020-00840-w
    This research has proved that mechanomyographic (MMG) signals can be used for evaluating muscle performance. Stimulation of the lost physiological functions of a muscle using an electrical signal has been determined crucial in clinical and experimental settings in which voluntary contraction fails in stimulating specific muscles. Previous studies have already indicated that characterizing contractile properties of muscles using MMG through neuromuscular electrical stimulation (NMES) showed excellent reliability. Thus, this review highlights the use of MMG signals on evaluating skeletal muscles under electrical stimulation. In total, 336 original articles were identified from the Scopus and SpringerLink electronic databases using search keywords for studies published between 2000 and 2020, and their eligibility for inclusion in this review has been screened using various inclusion criteria. After screening, 62 studies remained for analysis, with two additional articles from the bibliography, were categorized into the following: (1) fatigue, (2) torque, (3) force, (4) stiffness, (5) electrode development, (6) reliability of MMG and NMES approaches, and (7) validation of these techniques in clinical monitoring. This review has found that MMG through NMES provides feature factors for muscle activity assessment, highlighting standardized electromyostimulation and MMG parameters from different experimental protocols. Despite the evidence of mathematical computations in quantifying MMG along with NMES, the requirement of the processing speed, and fluctuation of MMG signals influence the technique to be prone to errors. Interestingly, although this review does not focus on machine learning, there are only few studies that have adopted it as an alternative to statistical analysis in the assessment of muscle fatigue, torque, and force. The results confirm the need for further investigation on the use of sophisticated computations of features of MMG signals from electrically stimulated muscles in muscle function assessment and assistive technology such as prosthetics control.
    Matched MeSH terms: Mechanical Phenomena*
  9. Utami D, Ubaidillah, Mazlan SA, Imaduddin F, Nordin NA, Bahiuddin I, et al.
    Materials (Basel), 2018 Nov 06;11(11).
    PMID: 30404193 DOI: 10.3390/ma11112195
    This paper investigates the field-dependent rheological properties of magnetorheological (MR) fluid used to fill in MR dampers after long-term cyclic operation. For testing purposes, a meandering MR valve was customized to create a double-ended MR damper in which MR fluid flowed inside the valve due to the magnetic flux density. The test was conducted for 170,000 cycles using a fatigue dynamic testing machine which has 20 mm of stroke length and 0.4 Hz of frequency. Firstly, the damping force was investigated as the number of operating cycles increased. Secondly, the change in viscosity of the MR fluid was identified as in-use thickening (IUT). Finally, the morphological observation of MR particles was undertaken before and after the long-term operation. From these tests, it was demonstrated that the damping force increased as the number of operating cycles increases, both when the damper is turn on (on-state) and off (off-state). It is also observed that the particle size and shape changed due to the long operation, showing irregular particles.
    Matched MeSH terms: Mechanical Phenomena
  10. Ullah S, Zainol I, Idrus RH
    Int J Biol Macromol, 2017 Nov;104(Pt A):1020-1029.
    PMID: 28668615 DOI: 10.1016/j.ijbiomac.2017.06.080
    The zinc oxide nanoparticles (particles size <50nm) incorporated into chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds.
    Matched MeSH terms: Mechanical Phenomena*
  11. Thompson MS, Bajuri MN, Khayyeri H, Isaksson H
    Proc Inst Mech Eng H, 2017 May;231(5):369-377.
    PMID: 28427319 DOI: 10.1177/0954411917692010
    Tendons are adapted to carry large, repeated loads and are clinically important for the maintenance of musculoskeletal health in an increasing, actively ageing population, as well as in elite athletes. Tendons are known to adapt to mechanical loading. Also, their healing and disease processes are highly sensitive to mechanical load. Computational modelling approaches developed to capture this mechanobiological adaptation in tendons and other tissues have successfully addressed many important scientific and clinical issues. The aim of this review is to identify techniques and approaches that could be further developed to address tendon-related problems. Biomechanical models are identified that capture the multi-level aspects of tendon mechanics. Continuum whole tendon models, both phenomenological and microstructurally motivated, are important to estimate forces during locomotion activities. Fibril-level microstructural models are documented that can use these estimated forces to detail local mechanical parameters relevant to cell mechanotransduction. Cell-level models able to predict the response to such parameters are also described. A selection of updatable mechanobiological models is presented. These use mechanical signals, often continuum tissue level, along with rules for tissue change and have been applied successfully in many tissues to predict in vivo and in vitro outcomes. Signals may include scalars derived from the stress or strain tensors, or in poroelasticity also fluid velocity, while adaptation may be represented by changes to elastic modulus, permeability, fibril density or orientation. So far, only simple analytical approaches have been applied to tendon mechanobiology. With the development of sophisticated computational mechanobiological models in parallel with reporting more quantitative data from in vivo or clinical mechanobiological studies, for example, appropriate imaging, biochemical and histological data, this field offers huge potential for future development towards clinical applications.
    Matched MeSH terms: Biomechanical Phenomena; Mechanical Phenomena*
  12. TermehYousefi A, Azhari S, Khajeh A, Hamidon MN, Tanaka H
    Mater Sci Eng C Mater Biol Appl, 2017 Aug 01;77:1098-1103.
    PMID: 28531983 DOI: 10.1016/j.msec.2017.04.040
    Haptic sensors are essential devices that facilitate human-like sensing systems such as implantable medical devices and humanoid robots. The availability of conducting thin films with haptic properties could lead to the development of tactile sensing systems that stretch reversibly, sense pressure (not just touch), and integrate with collapsible. In this study, a nanocomposite based hemispherical artificial fingertip fabricated to enhance the tactile sensing systems of humanoid robots. To validate the hypothesis, proposed method was used in the robot-like finger system to classify the ripe and unripe tomato by recording the metabolic growth of the tomato as a function of resistivity change during a controlled indention force. Prior to fabrication, a finite element modeling (FEM) was investigated for tomato to obtain the stress distribution and failure point of tomato by applying different external loads. Then, the extracted computational analysis information was utilized to design and fabricate nanocomposite based artificial fingertip to examine the maturity analysis of tomato. The obtained results demonstrate that the fabricated conformable and scalable artificial fingertip shows different electrical property for ripe and unripe tomato. The artificial fingertip is compatible with the development of brain-like systems for artificial skin by obtaining periodic response during an applied load.
    Matched MeSH terms: Mechanical Phenomena
  13. Taufiqurrahman I, Ahmad A, Mustapha M, Lenggo Ginta T, Ady Farizan Haryoko L, Ahmed Shozib I
    Materials (Basel), 2021 Feb 27;14(5).
    PMID: 33673716 DOI: 10.3390/ma14051129
    Welding parameters obviously determine the joint quality during the resistance spot welding process. This study aimed to investigate the effect of welding current and electrode force on the heat input and the physical and mechanical properties of a SS316L and Ti6Al4V joint with an aluminum interlayer. The weld current values used in this study were 11, 12, and 13 kA, while the electrode force values were 3, 4, and 5 kN. Welding time and holding time remained constant at 30 cycles. The study revealed that, as the welding current and electrode force increased, the generated heat input increased significantly. The highest tensile-shear load was recorded at 8.71 kN using 11 kA of weld current and 3 kN of electrode force. The physical properties examined the formation of a brittle fracture and several weld defects on the high current welded joint. The increase in weld current also increased the weld diameter. The microstructure analysis revealed no phase transformation on the SS316L interface; instead, the significant grain growth occurred. The phase transformation has occurred on the Ti6Al4V interface. The intermetallic compound layer was also investigated in detail using the EDX (Energy Dispersive X-Ray) and XRD (X-Ray Diffraction) analyses. It was also found that both stainless steel and titanium alloy have their own fusion zone, which is indicated by the highest microhardness value.
    Matched MeSH terms: Mechanical Phenomena
  14. Tao J, Chen J, Li J, Mathurin L, Zheng JC, Li Y, et al.
    Proc Natl Acad Sci U S A, 2017 09 12;114(37):9832-9837.
    PMID: 28855335 DOI: 10.1073/pnas.1709163114
    The optimal functionalities of materials often appear at phase transitions involving simultaneous changes in the electronic structure and the symmetry of the underlying lattice. It is experimentally challenging to disentangle which of the two effects--electronic or structural--is the driving force for the phase transition and to use the mechanism to control material properties. Here we report the concurrent pumping and probing of Cu2S nanoplates using an electron beam to directly manipulate the transition between two phases with distinctly different crystal symmetries and charge-carrier concentrations, and show that the transition is the result of charge generation for one phase and charge depletion for the other. We demonstrate that this manipulation is fully reversible and nonthermal in nature. Our observations reveal a phase-transition pathway in materials, where electron-induced changes in the electronic structure can lead to a macroscopic reconstruction of the crystal structure.
    Matched MeSH terms: Mechanical Phenomena
  15. Sri Harjanto, Latifa N. Noviana, Mia Diniati, Stefanno W. Yunior, Nasruddin
    Sains Malaysiana, 2015;44:747-752.
    Coal-based activated carbon materials is a prospective materials for hydrogen storage application. The present work
    aimed to study the effect of post treatments including mechanical milling process and pelletization and simulating
    experimentally the conditions of pelletization of fine particles of activated coal. Post treatment of activated coal consist
    of 2 steps mechanical milling process in planetary ball mill followed by pelletization. First step of mechanical milling
    process gave particle size reduction and second step was undertaken to maintain activity of activated coal. Second step
    of mechanochemical process were done in dry (ACP-A) and wet condition (ACP-B) with the ratio of sample: KOH was
    1:1 and performed for 1 h. Then they will be formed into pellets with the addition of binder which contained fructose,
    glucose and oligo. Some examinations such as PSA, BET, SEM and XRD were performed to determine the characteristics of
    activated carbon materials including hydrogen adsorption capacity testing. Particle size reduction of activated carbon
    reached 98.9% after planetary ball milling. The raw material of activated carbon (AC) has hydrogen adsorption as much
    as from 0.30 and 0.25 wt. % from -5 and 25o
    C measurements, respectively. As predicted the adsorption of hydrogen gas
    of pelletized activated carbon from bituminous coal decreased due to post treatment process about 47% for ACP-A and
    60% for ACP-B at 4000 Bar.
    Matched MeSH terms: Mechanical Phenomena
  16. Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Molecules, 2012 Feb 16;17(2):1969-91.
    PMID: 22343368 DOI: 10.3390/molecules17021969
    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
    Matched MeSH terms: Mechanical Phenomena
  17. Silverajah VS, Ibrahim NA, Zainuddin N, Yunus WM, Hassan HA
    Molecules, 2012 Oct 08;17(10):11729-47.
    PMID: 23044711 DOI: 10.3390/molecules171011729
    Poly(lactic acid) (PLA) is known to be a useful material in substituting the conventional petroleum-based polymer used in packaging, due to its biodegradability and high mechanical strength. Despite the excellent properties of PLA, low flexibility has limited the application of this material. Thus, epoxidized palm olein (EPO) was incorporated into PLA at different loadings (1, 2, 3, 4 and 5 wt%) through the melt blending technique and the product was characterized. The addition of EPO resulted in a decrease in glass transition temperature and an increase of elongation-at-break, which indicates an increase in the PLA chain mobility. PLA/EPO blends also exhibited higher thermal stability than neat PLA. Further, the PLA/1 wt% EPO blend showed enhancement in the tensile, flexural and impact properties. This is due to improved interaction in the blend producing good compatible morphologies, which can be revealed by Scanning Electron Microscopy (SEM) analysis. Therefore, PLA can be efficiently plasticized by EPO and the feasibility of its use as flexible film for food packaging should be considered.
    Matched MeSH terms: Mechanical Phenomena
  18. Shahmohammadi HR, Bakar J, Rahman RA, Adzhan NM
    J Food Sci, 2014 Feb;79(2):E178-83.
    PMID: 24410375 DOI: 10.1111/1750-3841.12324
    To improve textural attributes of puffed corn-fish snack, the effects of 1%, 1.5%, and 2% of calcium carbonate, magnesium silicate (talc), sodium bicarbonate as well as 5% and 10% of wheat bran (as the nucleating materials) on textural attributes were studied. Sensory evaluation, bulk density, expansion ratio, maximum force, and count peaks were measured using the Kramer test. The results showed that all of the additives except bran significantly enhanced the texture. Among them, talc at 0.5% was the best to enhance the density and expansion ratio. Effects of using 0.5% talc on puffed corn-fish snack microstructure were studied using scanning electron microscopy. The average cell diameter of 109 ± 48 μm and cell numbers per square centimeter of 67.4 for talc-treated products were obtained, while for nontalc-treated extrudates, average cell diameter of 798 ± 361 μm and cell numbers per square centimeter of 13.9 were found. Incorporation of 0.5% w/w of magnesium silicate reduced (7-fold) the average cell diameter while increased (4-fold) the cell number.
    Matched MeSH terms: Mechanical Phenomena
  19. Shahemi N, Liza S, Abbas AA, Merican AM
    J Mech Behav Biomed Mater, 2018 11;87:1-9.
    PMID: 30031358 DOI: 10.1016/j.jmbbm.2018.07.017
    A revision of a metal-on-ultra high molecular weight (UHMWPE) bearing couple for total hip replacement was performed due to aseptic loosening after 23 years in-vivo. It is a major long-term failure identified from wear generation. This study includes performing failure analysis of retrieved polyethylene acetabular cup from Zimmer Trilogy® Acetabular system. The UHMWPE acetabular cup was retrieved from a 61 years old male patient with ability to walk but limited leg movement when he presented to hospital in early 2016 with complaint left thigh pain. It was 23 years after his primary total hip replacement procedure. Surface roughness and morphology condition were measured using 3D laser microscope and Scanning Electron Microscope (SEM) to evaluate and characterize the wear features on polyethylene acetabular cup surface. ATR-Fourier Transform Infra-Red (ATR-FTIR), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) were used to characterize the chemical composition of carbon-oxygen bonding, crystallinity percentage and molecular weight of the polymer liner that might changes the mechanical properties of polyethylene. Nano indentation is to measure hardness and elasticity modulus where the ratio of hardness to elastic modulus value can be reflected as the degradation of mechanical properties. A prominent difference of thickness between two regions resulted from acentric loading concentration was observed and wear rate were measured. The linear wear rate for thin side and thick side were 0.33 mm/year and 0.05 mm/year respectively. Molecular weight reduction of 57.5% and relatively low ratio of hardness to elastic modulus (3.59 × 10-3) were the indicator of major mechanical properties degradation happened on UHMWPE acetabular cup. This major degradation was contributed by oxidation and polishing wear feature accompanied with delamination, craters, ripple and cracks were the indication of extensive usage of UHMWPE from the suggested life span of acetabular cup application.
    Matched MeSH terms: Mechanical Phenomena*
  20. Saba N, Safwan A, Sanyang ML, Mohammad F, Pervaiz M, Jawaid M, et al.
    Int J Biol Macromol, 2017 Sep;102:822-828.
    PMID: 28455253 DOI: 10.1016/j.ijbiomac.2017.04.074
    The current study presents about the effect of cellulose nanofibers (CNFs) filler on the thermal and dynamic mechanical analysis (DMA) of epoxy composites as a function of temperature. In this study hand lay-up method was used to fabricate CNF reinforced Epoxy nanocomposites with CNF loading of 0.5%, 0.75%, and 1% into epoxy resin. The obtained thermal and DMA results illustrates that thermal stability, char content, storage modulus (E'), loss modulus (E") and glass transition temperature (Tg) increases for all CNF/epoxy nanocomposites compared to the pure epoxy. Thermal results revealed that 0.75% offers superior resistance or stability towards heat compared to its counterparts. In addition, 0.75% CNF/epoxy nanocomposites confers highest value of storage modulus as compared to 0.5% and 1% filler loading. Hence, it is concluded that 0.75% CNFs loading is the minimal to enhance both thermal and dynamic mechanical properties of the epoxy composites and can be utilized for advance material applications where thermal stability along with renewability are prime requirements.
    Matched MeSH terms: Mechanical Phenomena*
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