Displaying publications 1 - 20 of 66 in total

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  1. A facile, bio-based, novel approach for synthesis of covalently functionalized graphene nanoplatelet nano-coolants toward improved thermo-physical and heat transfer properties
    Sadri R, Hosseini M, Kazi SN, Bagheri S, Abdelrazek AH, Ahmadi G, et al.
    J Colloid Interface Sci, 2018 Jan 01;509:140-152.
    PMID: 28898734 DOI: 10.1016/j.jcis.2017.07.052
    In this study, we synthesized covalently functionalized graphene nanoplatelet (GNP) aqueous suspensions that are highly stable and environmentally friendly for use as coolants in heat transfer systems. We evaluated the heat transfer and hydrodynamic properties of these nano-coolants flowing through a horizontal stainless steel tube subjected to a uniform heat flux at its outer surface. The GNPs functionalized with clove buds using the one-pot technique. We characterized the clove-treated GNPs (CGNPs) using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). We then dispersed the CGNPs in distilled water at three particle concentrations (0.025, 0.075 and 0.1wt%) in order to prepare the CGNP-water nanofluids (nano-coolants). We used ultraviolet-visible (UV-vis) spectroscopy to examine the stability and solubility of the CGNPs in the distilled water. There is significant enhancement in thermo-physical properties of CGNPs nanofluids relative those for distilled water. We validated our experimental set-up by comparing the friction factor and Nusselt number for distilled water obtained from experiments with those determined from empirical correlations, indeed, our experimental set-up is reliable and produces results with reasonable accuracy. We conducted heat transfer experiments for the CGNP-water nano-coolants flowing through the horizontal heated tube in fully developed turbulent condition. Our results are indeed promising since there is a significant enhancement in the Nusselt number and convective heat transfer coefficient for the CGNP-water nanofluids, with only a negligible increase in the friction factor and pumping power. More importantly, we found that there is a significant increase in the performance index, which is a positive indicator that our nanofluids have potential to substitute conventional coolants in heat transfer systems because of their overall thermal performance and energy savings benefits.
    Matched MeSH terms: Friction
  2. Analysis of laser sintered materials using finite element method
    AHMAD SHAHIR BIN JAMALUDIN, ABDULLAH BIN YASSIN
    Sains Malaysiana, 2013;42:1727-1733.
    Invention of milling combined laser sintering system (MLSS) is able to reduce the mould manufacturing time and improve the mould accuracy. Thus, more study is needed to increase the understanding for the laser sintered material machining characteristic to gain benefit from the invention of MLSS. This paper clarified the analysis of laser sintered material machinability with the application of Finite Element Method (FEM). Mild steel AISI1055 was applied in developing the Finite Element model in this study due to its popularity in machinability test and adequate level of data availability. 2D orthogonal cutting was employed on edge design tools with updated Lagrangian coupled thermo mechanical plane strain model. Adaptive meshing, tool edge radius and various types of friction models were assigned to obtain efficient simulations and precise cutting results. Cutting force and cutting-edge temperature estimated by Finite Element Method are validated against corresponding experimental values by previous researchers. In the study, cutting force increases when radial depth increases and lowest error acquired when the shear friction factor of 0.8 was applied. Machining simulation for laser sintered materials estimated lower cutting force compared with mild steel AISI1055 due to lower Young modulus. Higher cutting temperature estimated for machining simulation laser sintered material compared with machining simulation mild steel AISI1055 due to its low thermal conductivity.
    Matched MeSH terms: Friction
  3. Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent
    Federle W, Baumgartner W, Hölldobler B
    J Exp Biol, 2004 Jan;207(Pt 1):67-74.
    PMID: 14638834
    Tarsal adhesive pads enable insects to hold on to smooth plant surfaces. Using a centrifuge technique, we tested whether a "wet adhesion" model of a thin film of liquid secreted between the pad and the surface can explain adhesive and frictional forces in Asian Weaver ants (Oecophylla smaragdina). When forces are acting parallel to the surface, pads in contact with the surface can slide smoothly. Force per unit pad contact area was strongly dependent on sliding velocity and temperature. Seemingly consistent with the effect of a thin liquid film in the contact zone, (1) frictional force linearly increased with sliding velocity, (2) the increment was greater at lower temperatures and (3) no temperature dependence was detected for low-rate perpendicular detachment forces. However, we observed a strong, temperature-independent static friction that was inconsistent with a fully lubricated contact. Static friction was too large to be explained by the contribution of other (sclerotized) body parts. Moreover, the rate-specific increase of shear stress strongly exceeded predictions derived from estimates of the adhesive liquid film's thickness and viscosity. Both lines of evidence indicate that the adhesive secretion alone is insufficient to explain the observed forces and that direct interaction of the soft pad cuticle with the surface ("rubber friction") is involved.
    Matched MeSH terms: Friction
  4. Fulltext Closed form solutions for unsteady free convection flow of a second grade fluid over an oscillating vertical plate
    Ali F, Khan I, Shafie S
    PLoS One, 2014;9(2):e85099.
    PMID: 24551033 DOI: 10.1371/journal.pone.0085099
    Closed form solutions for unsteady free convection flows of a second grade fluid near an isothermal vertical plate oscillating in its plane using the Laplace transform technique are established. Expressions for velocity and temperature are obtained and displayed graphically for different values of Prandtl number Pr, thermal Grashof number Gr, viscoelastic parameter α, phase angle ωτ and time τ. Numerical values of skin friction τ 0 and Nusselt number Nu are shown in tables. Some well-known solutions in literature are reduced as the limiting cases of the present solutions.
    Matched MeSH terms: Friction
  5. Combined similarity-numerical solutions of MHD boundary layer slip flow of non-Newtonian power-law nanofluids over a radiating moving plate
    Nur Husna Md. Yusoff, Md. Jashim Uddin, Ahmad Izani Md. Ismail
    Sains Malaysiana, 2014;43:151-159.
    A combined similarity-numerical solution of the magnetohydrodynamic boundary layer slip flow of an electrically conducting non-Newtonian power-law nanofluid along a heated radiating moving vertical plate is explored. Our nanofluid model incorporates the influences of the thermophoresis and the Brownian motion. The basic transport equations are made dimensionless first and then suitable similarity transformations are applied to reduce them into a set of nonlinear ordinary differential equations with the associated boundary conditions. The reduced equations are then solved numerically. Graphical results for the non-dimensional flow velocity, the temperature and the nanoparticles volume fraction profiles as well as for the friction factor, the local Nusselt and the Sherwood numbers are exhibited and examined for various values of the controlling parameters to display the interesting aspects of the solutions. It was found that the friction factor increases with the increase of the magnetic field (M), whilst it is decreased with the linear momentum slip parameter (a). The linear momentum slip parameter (a) reduces the heat transfer rates and the nanoparticles volume fraction rates. Our results are compatible with the existing results for a special case.
    Matched MeSH terms: Friction
  6. Comfort and frictional properties of dental gloves
    Roberts AD, Brackley CA
    J Dent, 1996 Sep;24(5):339-43.
    PMID: 8916648
    OBJECTIVES: A survey of general dental practitioners and dental surgery assistants was carried out to ascertain their preferences and opinions on powder-free hydrogel-coated gloves compared with starch-powdered gloves. The aim was to relate the survey findings to laboratory measurements of the frictional characteristics of glove inner surfaces and their water absorptive capability.

    METHODS: The survey was carried out using a questionnaire given to local dental practitioners. Glove friction and water absorption measurements were made using specially designed equipment.

    RESULTS: The survey showed that a selected group of dentist and dental surgery assistants preferred hydrogel-coated gloves, particularly for damp donning, durability and long-term wear comfort. Laboratory measurements showed that the hydrogel coating gave a low friction coefficient against damp skin. The coating was durable, and absorbed water more readily than other treatments.

    CONCLUSION: A survey of dental practitioners and dental surgery assistants and laboratory measurements indicates that hydrogel-coated gloves have superior properties, and are preferred to other non-sterile glove types.

    Matched MeSH terms: Friction
  7. Fulltext Conjugate effects of heat and mass transfer on MHD free convection flow over an inclined plate embedded in a porous medium
    Ali F, Khan I, Samiulhaq, Shafie S
    PLoS One, 2013;8(6):e65223.
    PMID: 23840321 DOI: 10.1371/journal.pone.0065223
    The aim of this study is to present an exact analysis of combined effects of radiation and chemical reaction on the magnetohydrodynamic (MHD) free convection flow of an electrically conducting incompressible viscous fluid over an inclined plate embedded in a porous medium. The impulsively started plate with variable temperature and mass diffusion is considered. The dimensionless momentum equation coupled with the energy and mass diffusion equations are analytically solved using the Laplace transform method. Expressions for velocity, temperature and concentration fields are obtained. They satisfy all imposed initial and boundary conditions and can be reduced, as special cases, to some known solutions from the literature. Expressions for skin friction, Nusselt number and Sherwood number are also obtained. Finally, the effects of pertinent parameters on velocity, temperature and concentration profiles are graphically displayed whereas the variations in skin friction, Nusselt number and Sherwood number are shown through tables.
    Matched MeSH terms: Friction
  8. Fulltext Correlation between the bending strength and the thickness interlayer of alumina-mild steel friction welded at lower rotational speed
    Mohamad Zaky Noh, Luay Bakir Hussain, Zainal Arifin Ahmad
    Journal of Nuclear and Related Technologies, 2007;2007(1):75-82.
    MyJurnal
    The joining of ceramic-metal could be done through a few techniques: brazing, diffusion bonding, friction welding etc. However, the mechanism of ceramic-metal joining was still not properly understood. In this study, alumina rod was bonded to mild steel rod via friction welding technique by using Al 1100 sheet as interlayer. The diameter of the rods was 10 mm. Friction pressure of 20 MPa and forging pressure of 40 MPa were used. Rotational speeds were maintained at 900 rpm and friction times of 2 to 20 seconds were applied. The joining strength was determined through four point bending test. The maximum bending strength, 240 MPa was obtained at the friction times of 20 seconds. Under optical microscope and SEM observation, the deformation of the aluminum interface was clearly obtained. Mechanical interlocking and close contact between the aluminaaluminum and aluminum-mild steel were observed at magnifications of 3000X. The strength of alumina-steel bonding is much dependent on the wettability of the alumina surface by the molten aluminum and the existing of mechanical interlocking between interlayer and sample materials.
    Matched MeSH terms: Friction
  9. Fulltext Correlation of electrical resistivity with some soil parameters for the development of possible prediction of slope stability and bearing capacity of soil using electrical parameters
    Syed Baharom Syed Osman, Mohammad Nabil Fikri, Fahad Irfan Siddique
    Pertanika Journal of Science & Technology, 2014;22(1):139-152.
    MyJurnal
    The long term objective of this research is to look into the possibility of replacing soil strength parameters such as cohesion and angle of friction with electrical resistivity value for the purpose of computing among others, factor of safety in slopes or bearing capacity of soil. This paper however is limited to the investigation of correlation between electrical resistivity with some selected soil parameters. Electrical resistivity tests, using a basic multi meter, steel moulds and other related equipment, were conducted in the laboratory on soil samples with variations in soil type, compaction energy and moisture content. The samples consisted of predominantly clay, silt and sandy size particles and were compacted in a 100 x 100 mm square mould, while the corresponding electrical resistivity tests were carried out using the disc electrode method in accordance to BS 1377. The values of the electrical parameters such as voltage, current and resistance, with the corresponding value of soil parameters such as cohesion, angle of friction and moisture content, were measured and recorded. The results of the tests produced some initial crude relationships between electrical resistivity and the selected soil parameters. The strongest correlation between electrical resistivity and angle of internal friction, φ, was obtained from the clay size samples with R2 of 0.824, while the maximum correlation between electrical resistivity and moisture content again was obtained through the clay samples with R2 of 0.818. From the other results and graphs analyzed, some consistencies and specific trends of behaviour observed gave some early indications that a more detail and precise correlation between electrical resistivity and soil strength parameters could be very well possible in future.
    Matched MeSH terms: Friction
  10. Fulltext Design and fabrication of brake pad testing apparatus for teaching and learning application
    Leman, A.M., Che Wan Izzudin, Md Zin Ibrahim, Dafit Feriyanto
    Journal of Occupational Safety and Health, 2015;12(2):87-92.
    MyJurnal
    Brake pad apparatus is designed for help student and instructor in teaching and learning application. The objective
    of this research is to differentiate the pressure effect and braking temperature condition of different pad. This apparatus
    also aimed for learning the safety car and motorcycle braking system. This apparatus can to compare with theoretical
    calculation in order to approve that this apparatus is useful. The main concept in this apparatus is thermocouple use
    to detect the temperature gain while braking process. Speed motor controller used for set the angular velocity of the
    motor in braking process. Pressure applied at brake pedal detected by pressure gauge and data logger function as a
    connector. This apparatus also designed based on valid data for average of teenager in Malaysia which made on a
    sample university student. Result show that the apparatus can function effectively by defines the different temperature
    when applied the different pressure and different pad. Pad C shows the 880C for thermocouple 1 and 790C for
    thermocouple 2 at the 20 psi and infrared thermometer show 1130C for pad C. Graph from calculation shows that the
    pad A have 216.480C at 1000 rpm which have low temperature than pad B, C and D. high efficiency of friction and
    pressure applied will cause more heat generate than low coefficient of friction and pressure applied.
    Matched MeSH terms: Friction
  11. Fulltext Developed steady-state response for a new hybrid damper mounted on structures
    Ziaee M, Hejazi F
    PLoS One, 2023;18(8):e0290248.
    PMID: 37590241 DOI: 10.1371/journal.pone.0290248
    Coulomb friction is considered as a mechanical approach to diminish the structural responses during the excitations. However, in case of severe oscillations supplementary mechanisms are employed besides the friction to mitigate the destructive effects of the vibrations in structures. Therefore, the main goal of this research is to develop a new Hybrid System (HS) which is a parallel combination of Viscous Damping (VD) and Coulomb friction for structures subjected to dynamic load. To achieve this goal, the effect of viscous damper is embedded in the equation of motion which is proposed by Den Hartog for a Single-Degree-of-Freedom (SDOF) Coulomb system, and has been extensively implemented for past few decades. In the considered numerical example in this study, implementing the proposed HDM in system resulted in decreasing the maximum displacement in the range of 1% to 98% for different amounts of force amplitude and viscous damping ratios. Also, applying the proposed HDM increased the time lag for about up to 24% for the frequency ratios greater than 1. The developed hybridized system in this study can be utilised as new generation of Tuned Mass Damper (TMD) to improve their energy dissipating efficiency under severe excitations.
    Matched MeSH terms: Friction
  12. Dry sliding wear behaviour of talc-reinforced UHMWPE composite for implant application
    Chang BP, Hazizan Md Akil, Ramdziah bt Md Nasir
    Sains Malaysiana, 2015;44:819-825.
    As of today, ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic material normally used as bearing
    components for human joint replacements. However, formation of wear debris from UHMWPE after certain service
    periods may cause adverse effects which remain as unresolved issues. In this study, mechanical and dry sliding wear
    properties of UHMWPE reinforced with different loading of talc particles were investigated. The wear test was carried
    out using Ducom TR-20 pin-on-disc tester at different pressure velocity (pv) factors under dry sliding conditions. The
    worn surfaces and transfer films of pure UHMWPE and talc/UHMWPE composites were observed under scanning electron
    microscope (SEM). The experimental results showed that the microhardness increased with the increase of talc loadings
    in UHMWPE. The 20 wt. % talc/UHMWPE composites showed a 17% increment in microhardness as compared with pure
    UHMWPE. The dry sliding wear behaviour of UHMWPE was also improved upon the reinforcement of talc. The wear rate
    of UHMWPE decreased after incorporation of talc particles. The coefficient of friction (COF) increased slightly under low
    pv conditions. At high pv conditions, the COF decreased in values with increasing talc loadings. The improvement in
    wear behaviour may be attributed to the increase in load-carrying capacity and surface hardness of the talc/UHMWPE
    composites. SEM micrographs on worn surfaces showed that plastic deformation and grooving wear were dominant for
    UHMWPE. The plastic deformation and grooving wear were reduced upon the reinforcement of talc particles. The talc/
    UHMWPE composites produced smoother and uniform transfer films as compared to pure UHMWPE.
    Matched MeSH terms: Friction
  13. Fulltext Effect of Tilt Angle and Pin Depth on Dissimilar Friction Stir Lap Welded Joints of Aluminum and Steel Alloys
    Chitturi V, Pedapati SR, Awang M
    Materials (Basel), 2019 Nov 26;12(23).
    PMID: 31779107 DOI: 10.3390/ma12233901
    Automobile, aerospace, and shipbuilding industries are looking for lightweight materials for cost effective manufacturing which demands the welding of dissimilar alloy materials. In this study, the effect of tool rotational speed, welding speed, tilt angle, and pin depth on the weld joint were investigated. Aluminum 5052 and 304 stainless-steel alloys were joined by friction stir welding in a lap configuration. The design of the experiments was based on Taguchi's orthogonal array for conducting the experiments with four factors and three levels for each factor. The microstructural analysis showed tunnel defects, micro voids, and cracks which formed with 0° and 1.5° tilt angles. The defects were eliminated when the tilt angle increased to 2.5° and a mixed stir zone was formed with intermetallic compounds. The presence of the intermetallic compounds increased with the increase in tilt angle and pin depth which further resulted in obtaining a defect-free weld. Hooks were formed on either side of the weld zone creating a mechanical link for the joint. A Vickers hardness value of HV 635.46 was achieved in the mixed stir zone with 1000 rpm, 20 mm/min, and 4.2 mm pin depth with a tilt angle of 2.5°, which increased by three times compared to the hardness of SS 304 steel. The maximum shear strength achieved with 800 rpm, 40 mm/min, and a 4.3 mm pin depth with a tilt angle of 2.5° was 3.18 kN.
    Matched MeSH terms: Friction
  14. Effect of Wear Conditions, Parameters and Sliding Motions on Tribological Characteristics of Basalt and Glass Fibre Reinforced Epoxy Composites
    Talib AAA, Jumahat A, Jawaid M, Sapiai N, Leao AL
    Materials (Basel), 2021 Feb 02;14(3).
    PMID: 33540915 DOI: 10.3390/ma14030701
    Basalt fibre is a promising mineral fibre that has high potential to replace synthetic based glass fibre in today's stringent environmental concern. In this study, friction and wear characteristics of glass and basalt fibres reinforced epoxy composites were studied and comparatively evaluated at two test stages. The first stage was conducted at fixed load, speed and distance under three different conditions; adhesive, abrasive and erosive wear, wherein each composite specimens slide against steel, silicon carbide, and sand mixtures, respectively. The second stage was conducted involving different types of adhesive sliding motions against steel counterpart; unidirectional and reciprocating motion, with the former varied at pressure-velocity (PV) factor; 0.23 MPa·m/s and 0.93 MPa·m/s, while the latter varied at counterpart's configuration; ball-on-flat (B-O-F) and cylinder-on-flat (C-O-F). It was found that friction and wear properties of composites are highly dependent on test conditions. Under 10 km test run, Basalt fibre reinforced polymer (BFRP) composite has better wear resistance against erosive sand compared to Glass fibre reinforced polymer (GFRP) composite. In second stage, BFRP composite showed better wear performance than GFRP composite under high PV of unidirectional sliding test and under B-O-F configuration of reciprocating sliding test. BFRP composite also exhibited better friction properties than GFRP composite under C-O-F configuration, although its specific wear rate was lower. In scanning electron microscopy examination, different types of wear mechanisms were revealed in each of the test conducted.
    Matched MeSH terms: Friction
  15. Effect of nano- and micro- reinforced agents on dry sliding wear of polyester composites
    Chong MM, Chang SY, Noraiham Muhammad, Zulkifli Mord Rosli, Qumrul Ahsan
    Sains Malaysiana, 2014;43:959-966.
    Dry sliding wear of polyester hybrid composites containing carboxylic functionalized multi-walled carbon nanotubes (cNT) and microparticles, silica (Si02) was studied at different sliding distances. An attempt has been made to produce uniform dispersion of nano- and micro- particles in the test samples by ultrasonication. The tribological properties of the hybrid composites were performed by using pin-on-disc (POD) tester against grey cast iron countersurface. The dry sliding wear tests were carried out under pressure-velocity (pv) condition of 0.4 MPa and 4 m/s for total sliding distance of 28800 m and at an interval of every sliding distance of 3600 m, wear properties and behavior were studied. The samples containing 10 wt.% silica (microparticles) with and without CNT always show increase in coefficient of friction at the expense of wear rate. However, samples containing only ci'rr have the lowest wear rate with the increase in coefficient of friction. Sliding distance studies also provide the information on wear rates which were ever changing at different sliding distances whereas average coefficient of friction did not vary throughout the tests. SEM observations of wear surfaces showed different wear morphologies when reinforcement (cNT or Si02) incorporated into the composites either alone or in combination.
    Matched MeSH terms: Friction
  16. Fulltext Effects of lubrication in warm powder compaction process
    Rahman, M.M., Nor, S.S.M., Rahman, H.Y.
    ASM Science Journal, 2011;5(1):11-18.
    MyJurnal
    Warm compaction is an advanced manufacturing technique which consists of two consecutive steps, i.e. powder compaction at above ambient temperature and sintering in a controlled environment. Due to the relative movement between the powder mass and die wall as well as sliding among powder particles, frictional force is generated during the compaction stage. Admixed lubricant is used during the compaction step in order to minimize friction and hence improve the uniformity of the density of distribution inside the component. However, during the sintering process, trapped lubricant is often found to be burnt out hence leaving pores or voids which result in the lower strength of the final products. Warm compaction was initiated in the nineties, however not much information has been published about the effects of lubrication on the quality of the components produced through this route. Therefore, this paper presents the outcome of an experimental investigation about the effects of lubrication on manufacturing near-net shape components through the warm compaction route. Iron powder ASC 100.29 was mixed mechanically with zinc stearate to prepare the feedstock. Mixing time, weight percentage of lubricant content and compaction temperature were varied during green compact generation while sintering temperature, heating rate and holding time were manipulated during sintering. The relative densities and strengths of the final products were investigated at every compaction as well as sintering parameter. The results revealed that lubrication could provide significant effects at the compaction temperature of 180ºC while no significant effect of lubrication was observed during sintering. The suitable lubricant content was found to be 0.4 wt% and mixing time was around 30 min and the sintering temperature was around 990ºC.
    Matched MeSH terms: Friction
  17. Effects of radiation on free convection from a heated horizontal circular cylinder in the presence of heat generation
    Zainuddin N, Saleh H, Hashim I, Roslan R
    Sains Malaysiana, 2016;45:315-321.
    Effects of radiation on free convection about a heated horizontal circular cylinder in the presence of heat generation is investigated numerically. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equations are transformed into dimensionless non-linear partial differential equations and solved by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determined the effects of radiation parameter, heat generation parameter, and the Prandtl number, on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of and are shown graphically.
    Matched MeSH terms: Friction
  18. Engine performance and emission characteristics of palm biodiesel blends with graphene oxide nanoplatelets and dimethyl carbonate additives
    Razzaq L, Mujtaba MA, Soudagar MEM, Ahmed W, Fayaz H, Bashir S, et al.
    J Environ Manage, 2021 Mar 15;282:111917.
    PMID: 33453625 DOI: 10.1016/j.jenvman.2020.111917
    This study investigated the engine performance and emission characteristics of biodiesel blends with combined Graphene oxide nanoplatelets (GNPs) and 10% v/v dimethyl carbonate (DMC) as fuel additives as well as analysed the tribological characteristics of those blends. 10% by volume DMC was mixed with 30% palm oil biodiesel blends with diesel. Three different concentrations (40, 80 and 120 ppm) of GNPs were added to these blends via the ultrasonication process to prepare the nanofuels. Sodium dodecyl sulphate (SDS) surfactant was added to improve the stability of these blends. GNPs were characterised using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR), while the viscosity of nanofuels was investigated by rheometer. UV-spectrometry was used to determine the stability of these nanoplatelets. A ratio of 1:4 GNP: SDS was found to produce maximum stability in biodiesel. Performance and emissions characteristics of these nanofuels have been investigated in a four-stroke compression ignition engine. The maximum reduction in BSFC of 5.05% and the maximum BTE of 22.80% was for B30GNP40DMC10 compared to all other tested blends. A reduction in HC (25%) and CO (4.41%) were observed for B30DMC10, while a reduction in NOx of 3.65% was observed for B30GNP40DMC10. The diesel-biodiesel fuel blends with the addition of GNP exhibited a promising reduction in the average coefficient of friction 15.05%, 8.68% and 3.61% for 120, 80 and 40 ppm concentrations compared to B30. Thus, combined GNP and DMC showed excellent potential for utilisation in diesel engine operation.
    Matched MeSH terms: Friction
  19. Fulltext Evaluation of the Effects of Cement and Lime with Rice Husk Ash as an Additive on Strength Behavior of Coastal Soil
    Eliaslankaran Z, Daud NNN, Yusoff ZM, Rostami V
    Materials (Basel), 2021 Feb 28;14(5).
    PMID: 33670914 DOI: 10.3390/ma14051140
    Coastal accretion and erosion are unavoidable processes as some coastal sediments undergo modification and stabilization. This study was conducted to investigate the geotechnical behavior of soil collected from Bagan Lalang coast and treated with lime, cement, and rice husk ash (RHA) to design a low-cost alternative mixture with environmentally friendly characteristics. Laboratory tests were carried out to analyze the physical properties of the soil (Atterberg limits and compaction properties), together with mechanical characteristics (direct shear and unconfined compressive strength (UCS) tests) to determine the effect of different ratios of stabilizer/pozzolan on the coastal soil and the optimum conditions for each mixture. Part of the purpose of this study was also to analyze the shear behavior of the coastal soil and monitor the maximum axial compressive stress that the treated specimens can bear under zero confining pressure. Compared to the natural soil, the soil treated with lime and rice husk ash (LRHA) in the ratio of 1:2 (8% lime content) showed a tremendous increase in shear stress under the normal stress of 200 kPa. The strength parameters such as the cohesion (c) and internal friction angle (ϕ) values showed a significant increase. Cohesion values increased considerably in samples cured for 90 days compared to specimens cured for 7 days with additional LRHA in the ratio of 1:2 (28%).
    Matched MeSH terms: Friction
  20. Falkner-skan solution for gravity-driven film flow of a micropolar fluid
    Kartini Ahmad, Roslinda Nazar, Pop I
    Sains Malaysiana, 2011;40:1291-1296.
    In this paper, the steady Falkner-Skan solution for gravity-driven film flow of a micropolar fluid is theoretically investigated. The resulting nonlinear ordinary differential equations are solved numerically using an implicit finite-difference scheme. The results obtained for the skin friction coefficient as well as the velocity and microrotation or angular velocity profiles are shown in table and figures for different values of the material or micropolar parameter K.
    Matched MeSH terms: Friction
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