Displaying publications 81 - 100 of 136 in total

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  1. Effect of high-speed parameters on uncoated carbide tool in finish turning titanium Ti-6A1-4V ELI
    Sulaiman M, Cbe Haron C, Ghani J, Kasim M
    Sains Malaysiana, 2014;43:111-116.
    In this work, the Sandvik uncoated carbide insert, CNGG 120408-SGF-H13A was used as a cutting tool in high-speed turning of titanium alloy Ti-6A1-4V EH (extra-low interstitial) with hardness of 32 HRC. Wear is one of the problems that cannot be avoided in machining process. Therefore, the objective of this paper was to investigate tool-wear behavior of various cutting-speed values (high-speed range) on the tool life of the cutting tools, especially in finishing titanium alloy. The experiments were performed under flooded coolant condition using water-based mineral-oil. The cutting speeds employed were 120, 170 and 220 mlmin. The feed rate was constant at 02 mm/rev and the depth of cut was 0.4 mm. Based on the results, the highest cutting speed of 220 m/min caused the highest wear rate. By linking the machine operations and the tool life curves obtained using flank wear data, the wear behavior of uncoated carbide was described.
    Matched MeSH terms: Alloys
  2. Multidisciplinary treatment approach to restore deep horizontally fractured maxillary central incisor
    Patil PG, Nimbalkar-Patil SP, Karandikar AB
    J Contemp Dent Pract, 2014 Jan 1;15(1):112-5.
    PMID: 24939276
    This case report demonstrates sequential periodontic, orthodontic and prosthodontic treatment modalities to save and restore deep horizontally fractured maxillary central incisor. The location of fracture was deep in the mucosa which reveals less than 2 mm of tooth structure to receive the crown. The procedures like surgical crown lengthening, endodontic post placement, orthodontic forced eruption, core build-up and metal-ceramic crown restoration were sequentially performed to conserve the fractured tooth. Forced eruption is preferred to surgical removal of supporting alveolar bone, since forced eruption preserves the biologic width, maintains esthetics, and at the same time exposes sound tooth structure for the placement of restorative margins.
    Matched MeSH terms: Metal Ceramic Alloys/chemistry
  3. Dataset on optimization of EDM machining parameters by using central composite design
    Soundhar A, Zubar HA, Sultan MTBHH, Kandasamy J
    Data Brief, 2019 Apr;23:103671.
    PMID: 30788395 DOI: 10.1016/j.dib.2019.01.019
    Newly prepared titanium alloy (Ti-13Zr-13Nb (TZN)) using powder metallurgy is considered in this investigation. Titanium alloys (TZN) are used in hip and knee replacement for orthopedic implants. Conventional machining, TZN alloys produce higher tool wear rate and poor surface quality, but this can be reduced by Electrical Discharge Machining (EDM) method. Moreover, EDM produce good biological and corrosion resistant surface. In this research, experiments were conducted by considering the influential process factors such as pulse on time, pulse off time, voltage, and current. The experiments were designed based on Response Surface Methodology (RSM) of face centered central composite design. Analysis of Variance (ANOVA) was conducted to identify the significance process factors and their relation to output responses such as Electrode Wear Rate (EWR), Surface Roughness (SR) and Material Removal Rate (MRR). Further, an empirical model was developed by RSM in order to predict the output responses.
    Matched MeSH terms: Alloys
  4. A comparative evaluation of cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper): a SEM study
    Reddy KB, Dash S, Kallepalli S, Vallikanthan S, Chakrapani N, Kalepu V
    J Contemp Dent Pract, 2013 Nov 1;14(6):1028-35.
    PMID: 24858745
    The present study was conducted to compare the cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper).
    Matched MeSH terms: Dental Alloys/chemistry*
  5. Fulltext A novel design, analysis and 3D printing of Ti-6Al-4V alloy bio-inspired porous femoral stem
    Mehboob H, Tarlochan F, Mehboob A, Chang SH, Ramesh S, Harun WSW, et al.
    J Mater Sci Mater Med, 2020 Aug 20;31(9):78.
    PMID: 32816091 DOI: 10.1007/s10856-020-06420-7
    The current study is proposing a design envelope for porous Ti-6Al-4V alloy femoral stems to survive under fatigue loads. Numerical computational analysis of these stems with a body-centered-cube (BCC) structure is conducted in ABAQUS. Femoral stems without shell and with various outer dense shell thicknesses (0.5, 1.0, 1.5, and 2 mm) and inner cores (porosities of 90, 77, 63, 47, 30, and 18%) are analyzed. A design space (envelope) is derived by using stem stiffnesses close to that of the femur bone, maximum fatigue stresses of 0.3σys in the porous part, and endurance limits of the dense part of the stems. The Soderberg approach is successfully employed to compute the factor of safety Nf > 1.1. Fully porous stems without dense shells are concluded to fail under fatigue load. It is thus safe to use the porous stems with a shell thickness of 1.5 and 2 mm for all porosities (18-90%), 1 mm shell with 18 and 30% porosities, and 0.5 mm shell with 18% porosity. The reduction in stress shielding was achieved by 28%. Porous stems incorporated BCC structures with dense shells and beads were successfully printed.
    Matched MeSH terms: Alloys/chemistry*
  6. Alloying behaviour and microstructural changes of a ti-10%mo-10%cr alloy on sintering process
    Eko Kurniawan, Tubagus N. Rohmannudin, Mohamad Rasidi Rasani, Zainuddin Sajuri, Junaidi Syarif
    Sains Malaysiana, 2018;47:811-817.
    This study aimed to investigate the effects of element diffusion on the alloying behaviour and microstructure of a Ti-10%Mo10%Cr
    alloy during sintering and furnace cooling. A theoretical calculation of the average diffusion distance for each
    element was performed to predict the alloying behaviour during sintering and furnace cooling. The Ti-10%Mo-10%Cr
    alloy was fabricated using a blended element powder metallurgy approach. Micrograph of the samples after sintering
    showed bright-circle structures and significantly decreased equiaxed structures. The number of plate-like structures
    increased with prolonged sintering time. Microstructural changes occurred because of element diffusion resulting from
    the prolonged sintering time. Moreover, the diffusion distance of each element also increased with prolonged sintering
    time. Although elements can sufficiently diffuse during both sintering and furnace cooling, the diffusion distance during
    sintering was considerably higher than that during furnace cooling for all elements. The diffusion distances of Cr and
    Mo were the highest and lowest, respectively, during sintering and furnace cooling. This study showed that alloying
    behaviour mostly occurred during sintering and was controlled by the diffusion of Mo atoms.
    Matched MeSH terms: Alloys
  7. Fulltext A Short Review on the Phase Structures, Oxidation Kinetics, and Mechanical Properties of Complex Ti-Al Alloys
    Lim HP, Liew WYH, Melvin GJH, Jiang ZT
    Materials (Basel), 2021 Mar 29;14(7).
    PMID: 33805462 DOI: 10.3390/ma14071677
    This paper reviews the phase structures and oxidation kinetics of complex Ti-Al alloys at oxidation temperatures in the range of 600-1000 °C. The mass gain and parabolic rate constants of the alloys under isothermal exposure at 100 h (or equivalent to cyclic exposure for 300 cycles) is compared. Of the alloying elements investigated, Si appeared to be the most effective in improving the oxidation resistance of Ti-Al alloys at high temperatures. The effect of alloying elements on the mechanical properties of Ti-Al alloys is also discussed. Significant improvement of the mechanical properties of Ti-Al alloys by element additions has been observed through the formation of new phases, grain refinement, and solid solution strengthening.
    Matched MeSH terms: Alloys
  8. Fulltext Parametric evaluation of electrical discharge coatings on nickel-titanium shape memory alloy in deionized water
    Mansor AF, Azmi AI, Zain MZM, Jamaluddin R
    Heliyon, 2020 Aug;6(8):e04812.
    PMID: 32913911 DOI: 10.1016/j.heliyon.2020.e04812
    Nickel-titanium shape memory alloy (NiTi) has a unique capacity to restore its initial shape after deformation, which is highly applicable to orthopaedic implantations, especially for the minimization of invasive surgeries. The high nickel content of this alloy can lead to unfavourable effects on the human body upon dissolution; thus, a reliable barrier of coatings on the NiTi surface is required to alleviate the nickel migration and increase its biocompatibility. In this paper, analyses of a titanium oxide layer development on NiTi surface using electrical discharge coating (EDC) process is presented. The recast layer thickness, crater sizes, and surface roughness were characterized based on five parameters; polarity, discharge duration, pulse interval, peak current, and gap voltage. The results show that the discharge duration is the most significant parameter to influence all responses, followed by peak current. The surface characteristics of the EDC substrate is depending on the crater formations and is highly correlated with the discharge energy intensity. As a result, appropriate parametric conditions of the electrical discharge coating process can enhance the NiTi surface for future medical applications, without compromising the shape memory effect.
    Matched MeSH terms: Alloys
  9. Fulltext Corrosion behaviour of Al-Si cast alloy reinforced with titanium diboride (TiB2) and scandium (Sc)
    Ibrahim, R.E., Talari, M.K., Sabrina, M. Yahaya, Rosmamuhamadani, R., Sulaiman, S., Ismail, M.I.S.
    Journal of Engineering and Science Research, 2018;2(2):1-8.
    MyJurnal
    The aluminium-silicon (Al-Si) based on Metal Matrix Composites (MMCs) is widely used in lightweight
    constructions and transport applications requiring a combination of high strength and ductility. A grain
    refinement plays a crucial role in improving characteristics and properties of Al alloys. In this investigation,
    titanium diboride (TiB2) and scandium (Sc) inoculants were added to the Al-Si alloys for grain refinement of
    an alloy. In this investigation, the corrosion resistance rate of Al-Si cast alloy reinforced by TiB2 and Sc were
    measured by potentiostat (AUTOLAB) instrument. The aim of this research is to investigate the corrosion
    rate for Al-Si-TiB2-Sc composites that immersed in different concentration of acidic solutions. Besides, the
    immersion time of acidic solutions also was investigated. All the samples were prepared accordingly for
    ASTM standard by the composition of 6.0 wt% TiB2 and 0.6wt% Sc. All the samples undergo cold mounting
    technique for easy handling on corrosion tests. Then the samples were immersed in two different
    concentrations acidic medium solutions, which were 0.1.and 1.0 M hydrochloric acids (HCl). The corrosion
    rate also was investigated for immersion samples of 1.0 M HCl for 21 days. From the results obtained, added
    TiB2 and Sc onto Al-Si alloy gave the better properties in corrosion resistance. Corrosion rates to reduce when
    the samples were immersed in a lower concentration of acidic medium, 0.1 HCl. However, there are some
    significant on the result but it still following the corrosion rates trend. Thus, improvements to reinforcement
    content need to be done in further research to cover the lack of this corrosion rates trend.
    Matched MeSH terms: Alloys
  10. Fulltext Investigations on Surface Roughness and Tool Wear Characteristics in Micro-Turning of Ti-6Al-4V Alloy
    Aslantas K, Danish M, Hasçelik A, Mia M, Gupta M, Ginta T, et al.
    Materials (Basel), 2020 Jul 06;13(13).
    PMID: 32640567 DOI: 10.3390/ma13132998
    Micro-turning is a micro-mechanical cutting method used to produce small diameter cylindrical parts. Since the diameter of the part is usually small, it may be a little difficult to improve the surface quality by a second operation, such as grinding. Therefore, it is important to obtain the good surface finish in micro turning process using the ideal cutting parameters. Here, the multi-objective optimization of micro-turning process parameters such as cutting speed, feed rate and depth of cut were performed by response surface method (RSM). Two important machining indices, such as surface roughness and material removal rate, were simultaneously optimized in the micro-turning of a Ti6Al4V alloy. Further, the scanning electron microscope (SEM) analysis was done on the cutting tools. The overall results depict that the feed rate is the prominent factor that significantly affects the responses in micro-turning operation. Moreover, the SEM results confirmed that abrasion and crater wear mechanism were observed during the micro-turning of a Ti6Al4V alloy.
    Matched MeSH terms: Alloys
  11. Custom ceramometal pontics in a Kennedy Class IV maxillary removable partial denture: a clinical report
    Kamsiah GH, Ramli Y, Idris AY
    Quintessence Int, 1993 May;24(5):311-2.
    PMID: 8362043
    A technique in which the custom-made anterior ceramometal pontics are securely attached to the metal framework of a Kennedy Class IV removable partial denture is described. This technique results in a more esthetic prosthesis with less palatal coverage.
    Matched MeSH terms: Metal Ceramic Alloys*
  12. Fulltext A novel and stable way for energy harvesting from Bi2Te3Se alloy based semitransparent photo-thermoelectric module
    Fatima N, Karimov KS, Qasuria TA, Ibrahim MA
    J Alloys Compd, 2020 Dec 30;849:156702.
    PMID: 32834521 DOI: 10.1016/j.jallcom.2020.156702
    In this research, due to the present pandemic of COVID-19, we are proposing a stable and fixed semitransparent photo-thermoelectric cell (PTEC) module for green energy harvesting. This module is based on the alloy of Bismuth Telluride Selenide (Bi2Te3Se), designed in a press tablet form and characterized under solar energy. Here, both aspects of solar energy i.e., light and heat are utilized for both energy production and water heating. The semitransparent PTEC converts heat energy directly to electrical energy due to the gradient of temperature between two electrodes (top and bottom) of thermoelectric cells. The PTEC is 25% transparent, which can be varied according to the necessity of the utilizer. The X-ray diffraction of material and electric characterization of module i.e., open-circuited voltage (VOC) and Seebeck coefficient were performed. The experimental observations disclose that in the proposed PTEC module with an increment in the average temperature (TAvg) from 34 to 60 °C, results in the rise of VOC ∼ 2.4 times. However, by modifying the size of heat-absorbing top electrode and by increasing the temperature gradient through the addition of water coolant under the bottom electrode, an uplift in the champion device results in as increment of VOC ∼5.5 times and Seebeck coefficient obtained was -250 μV/0C, respectively. Results show that not only the selection of material but also the external modifications in the device highly effective the power efficiency of the devices. The proposed modules can generate electric power from light and utilize the penetrating sunlight inside the room and for the heating of the water which also acts as a coolant. These semitransparent thermoelectric cells can be built-in within windows and roofs of buildings and can potentially contribute to green energy harvesting, in situations where movement is restricted locally or globally.
    Matched MeSH terms: Alloys
  13. Fulltext An investigation of microstructural, magnetic and microwave absorption properties of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4
    Mustaffa MS, Azis RS, Abdullah NH, Ismail I, Ibrahim IR
    Sci Rep, 2019 Oct 29;9(1):15523.
    PMID: 31664142 DOI: 10.1038/s41598-019-52233-2
    The enhancement of microwave absorbing properties in nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) via multiwall carbon nanotubes (MWCNT) growth is studied in this research work. Ni0.5Zn0.5Fe2O4 was initially synthesized by mechanical alloying followed by sintering at 1200 °C and the microstructural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powder was then used as a catalyst to grow MWCNT derived from chemical vapor deposition (CVD) method. The sample was mixed with epoxy resin and a hardener for preparation of composites. The composite of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 shown a maximum reflection loss (RL) of -19.34 dB at the frequency and bandwidth of 8.46 GHz and 1.24 GHz for an absorber thickness of 3 mm for losses less than -10 dB. This acquired result indicates that multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 could be used as a microwave absorber application in X-band.
    Matched MeSH terms: Alloys
  14. Fulltext Electrochemical data of single and hybrid sol-gel coating precursors for aluminum alloy corrosion protection in 3.5% NaCl
    Hussin MH
    Data Brief, 2019 Feb;22:971-976.
    PMID: 30740480 DOI: 10.1016/j.dib.2019.01.029
    The anti-corrosion performances of single(TEOS) and hybrid (APTES-TEOS) sol-gel coatings on Al alloy samples exposed to 3.5 wt% NaCl were evaluated employing electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The data acquired using the three corrosion analysis techniques were in accordance with each other where hybrid sol-gel coating offered the lowest corrosion rate and current density in comparison to the single precursor silanol coating. Tafel curves suggested that the hybrid silane coatings mitigate both the anodic and cathodic reactions simultaneously (mixed type inhibitor). These techniques justified that incorporation of hybrid sol-gel improved the Al corrosion protection performance considerably.
    Matched MeSH terms: Alloys
  15. Effect of experimental silane-based primers with various contents of 2-hydroxyethyl methacrylate on the bond strength of orthodontic adhesives
    Mustafa AA, Matinlinna JP, Razak AA, Hussin AS
    J Investig Clin Dent, 2015 Aug;6(3):161-9.
    PMID: 24415731 DOI: 10.1111/jicd.12083
    AIM: To evaluate in vitro the effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) in experimental silane-based primers on shear bond strength of orthodontic adhesives.

    METHODS: Different volume percentages of HEMA were tested in four experimental silane-based primer solutions (additions of HEMA: 0, 5.0 vol%, 25.0 vol% and 50.0 vol%). An experimental silane blend (primer) of 1.0 vol% 3-isocyanatopropyltrimethoxysilane (ICMS) + 0.5% bis-1,2-(triethoxysilyl) ethane (BTSE) was prepared and used. The experimental primers together with the control group were applied onto acid-etched premolars for attachment of orthodontic brackets. After artificial aging by thermocycling the shear-bond strength was measured. The fractured surfaces of all specimens were examined under scanning electron microscopy (SEM) to evaluate the failure mode on the enamel surface.

    RESULTS: The experimental primers showed the highest shear-bond strength of 21.15 MPa (SD ± 2.70 MPa) and with 25 vol% showed a highly significant increase (P < 0.05) in bond strength. The SEM images showed full penetration of adhesive agents when using silane-based primers. In addition, the SEM images suggested that the predominant failure type was not necessarily the same as for the failure propagation.

    CONCLUSIONS: This preliminary study suggested that nonacidic silane-based primers with HEMA addition might be an alternative to for use as adhesion promoting primers.

    Matched MeSH terms: Dental Alloys/chemistry
  16. Cytotoxicity evaluation of biodegradable Zn-3Mg alloy toward normal human osteoblast cells
    Murni NS, Dambatta MS, Yeap SK, Froemming GRA, Hermawan H
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:560-566.
    PMID: 25686984 DOI: 10.1016/j.msec.2015.01.056
    The recent proposal of using Zn-based alloys for biodegradable implants was not supported with sufficient toxicity data. This work, for the first time, presents a thorough cytotoxicity evaluation of Zn-3Mg alloy for biodegradable bone implants. Normal human osteoblast cells were exposed to the alloy's extract and three main cell-material interaction parameters: cell health, functionality and inflammatory response, were evaluated. Results showed that at the concentration of 0.75mg/ml alloy extract, cell viability was reduced by ~50% through an induction of apoptosis at day 1; however, cells were able to recover at days 3 and 7. Cytoskeletal changes were observed but without any significant DNA damage. The downregulation of alkaline phosphatase protein levels did not significantly affect the mineralization process of the cells. Significant differences of cyclooxygenase-2 and prostaglandin E2 inflammatory biomarkers were noticed, but not interleukin 1-beta, indicating that the cells underwent a healing process after exposure to the alloy. Detailed analysis on the cell-material interaction is further discussed in this paper.
    Matched MeSH terms: Alloys/pharmacology*
  17. In vitro degradation and cell viability assessment of Zn-3Mg alloy for biodegradable bone implants
    Dambatta MS, Murni NS, Izman S, Kurniawan D, Froemming GR, Hermawan H
    Proc Inst Mech Eng H, 2015 May;229(5):335-42.
    PMID: 25991712 DOI: 10.1177/0954411915584962
    This article reports the in vitro degradation and cytotoxicity assessment of Zn-3Mg alloy developed for biodegradable bone implants. The alloy was prepared using casting, and its microstructure was composed of Mg2Zn11 intermetallic phase distributed within a Zn-rich matrix. The degradation assessment was done using potentiodynamic polarization and electrochemical impedance spectrometry. The cell viability and the function of normal human osteoblast cells were assessed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium and alkaline phosphatase extracellular enzyme activity assays. The results showed that the degradation rate of the alloy was slower than those of pure Zn and pure Mg due to the formation of a high polarization resistance oxide film. The alloy was cytocompatible with the normal human osteoblast cells at low concentrations (<0.5 mg/mL), and its alkaline phosphatase activity was superior to pure Mg. This assessment suggests that Zn-3Mg alloy has the potential to be developed as a material for biodegradable bone implants, but the toxicity limit must be carefully observed.
    Matched MeSH terms: Alloys/toxicity; Alloys/chemistry*
  18. Degradation behavior of biodegradable Fe35Mn alloy stents
    Sing NB, Mostavan A, Hamzah E, Mantovani D, Hermawan H
    J Biomed Mater Res B Appl Biomater, 2015 Apr;103(3):572-7.
    PMID: 24954069 DOI: 10.1002/jbm.b.33242
    This article reports a degradation study that was done on stent prototypes made of biodegradable Fe35Mn alloy in a simulated human coronary arterial condition. The stent degradation was observed for a short-term period from 0.5 to 168 h, which simulates the early period of stenting procedure. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to quantify degradation rate and surface property of the stents. Results showed that signs of degradation were visible on both crimped and expanded stents after 1 h of test, mostly located on the stent's curvatures. The degradation rate of stent was higher compared to that of the original alloy, indicating the surface altering effect of stent fabrication processing to degradation. A single oxide layer was formed and detected as a porous structure with capacitive behavior. Expanded stents exhibited lower polarization resistance compared to the nonexpanded ones, indicating the cold work effect of expansion procedure to degradation.
    Matched MeSH terms: Alloys/chemistry*
  19. Characterization of the feedstock properties of metal injection-molded WC-Co with palm stearin binder system
    Sri Yulis M. Amin, Norhamidi Muhamad, Khairur Rijal Jamaludin, Fayyaz A, Heng SY
    Sains Malaysiana, 2014;43:123-128.
    Feedstock preparation, as well as its characterization, is crucial in the production of highly sintered parts with minimal defect. The hard metal powder - particularly, cemented carbide (wc-co) used in this study was investigated both physically and thermally to determine its properties before the mixing and injection molding stage. Several analyses were conducted, such as scanning electron microscopy, energy dispersive X-ray diffraction, pycnometer density, critical powder volume percentage (cPvP), as well as thermal tests, such as thermogravimetric analysis and differential scanning calorimetry. On the basis of the CPVP value, the feedstock, consisting of wc-co powder, was mixed with 60% palm stearin and 40% polyethylene at an optimal powder loading, within 2 to 5% lower than the CPVP value. The CPVP spotted value was 65%. The feedstock optimal value at 61% showed good rheological properties (pseudoplastic behavior) with an n value lower than 1, considerably low activation energy and high moldability index. These preliminary properties of the feedstock serve as a benchmark in designing the schedule for the next whole steps (i.e. injection, debinding and sintering processes).
    Matched MeSH terms: Alloys
  20. Predicting graded young modulus values of Ti alloys modified by ion implantation
    Hassan MH
    Med J Malaysia, 2004 May;59 Suppl B:164-5.
    PMID: 15468869
    There has been, and is still, concern about the high elastic modulus of Ti alloys compared to bone. Any reduction in the Young's modulus value of the implant is expected to enhance stress redistribution to the adjacent bone tissues, minimize stress shielding and eventually prolong device lifetime. Dynamic Monte Carlo simulation is used to predict the gradual reduction in Young's modulus values between the bulk of Ti alloys and the modified surface layers due to Ca ion implantation. The simulation can be used as a screening step when applying new alloys and/or coatings.
    Matched MeSH terms: Alloys/analysis; Alloys/chemical synthesis*
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