Displaying publications 41 - 60 of 68 in total

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  1. Lim KS, Yang HZ, Chong WY, Cheong YK, Lim CH, Ali NM, et al.
    Opt Express, 2013 Feb 11;21(3):2551-62.
    PMID: 23481713 DOI: 10.1364/OE.21.002551
    When an optical fiber is dipped in an etching solution, the internal stress profile in the fiber varies with the fiber diameter. We observed a physical contraction as much as 0.2% in the fiber axial dimension when the fiber was reduced from its original diameter to ~6 µm through analysis using high resolution microscope images of the grating period of an etched FBG at different fiber diameters. This axial contraction is related to the varying axial stress profile in the fiber when the fiber diameter is reduced. On top of that, the refractive index of fiber core increases with reducing fiber diameter due to stress-optic effect. The calculated index increment is as much as 1.8 × 10(-3) at the center of fiber core after the diameter is reduced down to ~6 µm. In comparison with the conventional model that assumes constant grating period and neglects the variation in stress-induced index change in fiber core, our proposed model indicates a discrepancy as much as 3nm in Bragg wavelength at a fiber diameter of ~6 µm.
    Matched MeSH terms: Computer-Aided Design
  2. Jalal Abdullah S, Shaikh Mohammed J
    Disabil Rehabil Assist Technol, 2019 11;14(8):849-858.
    PMID: 30556753 DOI: 10.1080/17483107.2018.1539130
    Purpose: Some wheelchair users continue to struggle in maneuvering a wheelchair and navigating through manual doors. Several smart wheelchairs and robotic manipulators were developed to minimize such challenges facing disabled people. Disappointingly, a majority of these high-tech solutions are restricted to laboratories and are not extensively available as commercial products. Previously, a low-tech wheelchair accessory (arc-shaped with many wheels) for pushing doors was modelled and simulated. This work demonstrates the fabrication and testing of the first-generation prototype of the accessory.Materials and methods: The accessory has side portions with a straight arrangement of wheels and a front portion with a straight-arc-straight arrangement of wheels. The accessory was fabricated using conventional manufacturing, off-the-shelf components, and 3D printed ABS fasteners. Stress analysis simulations were done for the fasteners that attach the front accessory to the wheelchair frame. The proof-of-concept of the prototype installed onto a powered wheelchair was tested with a door and an obstacle, each with ∼50 N resistance force.Results: Prototype tests demonstrate the ability of the accessory along with the mechanical robustness of the 3D printed fasteners to push open doors allowing easy navigation through doors and to push/glide against obstacles. The accessory is foldable and detachable.Conclusion: The low-cost of the accessory makes it affordable to many users intending to improve their quality of life. The current study provides an engineering perspective of the accessory, and a clinical perspective is crucial. Other potential applications of the wheelchair accessory include use with scooters, walkers and stretchers.Implications for rehabilitationLow-cost, low-tech accessory is foldable and detachable.Accessory is effective for pushing doors and pushing/gliding against obstacles.Protective nature of the front accessory could prove highly beneficial to some wheelchair users.
    Matched MeSH terms: Computer-Aided Design
  3. Ahmad Sofian, Shminan, Rehman, Ullah Khan, Wan Norizan, Wan Hashim, Iswandy, Jamaludin
    MyJurnal
    The world has suffered from a critical shortage of Personal Protective Equipment (PPE) (Riva et al., 2007) during the pandemic of Covid-19 for medical staffs, the front liners. Like the whole world, Malaysia also imposed the stay-at-home and Movement Control Order (MCO) to break the chain of infections and flatten the curve of cases. The supply of PPE became a challenge during the lock down. There have been joined efforts from various parties stepping up, with different ways to help the production process of these key equipment but mostly focus on PPTs for male. Another challenge was face mask for Muslim lady health workers who wear hijab. This paper is about how to overcome these challenges and designed a novel face mask clip for hijab, using 3D printing. The face mask clip is for wearing a mask over hijab and is designed by generating a 3D digital file using computer-aided design (Hourcade, Bullock-Rest, & Hansen, 2012) software. Then the 3D design was converted to Standard Tessellation Language (STL) format, for the use of 3D printing systems. Then the design was split into layers for precise printing. The clips were tested by the staff in faculty of Cognitive Sciences and Human Development, Universiti Malaysia Sarawak. Feedbacks were collected by an online survey using the modified System Usability Scale. The participants reported that the clips are very comfortable and easy to use.
    Matched MeSH terms: Computer-Aided Design
  4. Tamrin KF, Moghadasi K, Jalil MH, Sheikh NA, Mohamaddan S
    Materials (Basel), 2021 Apr 16;14(8).
    PMID: 33923675 DOI: 10.3390/ma14082009
    This study discloses a method for painting artwork using a CO2 laser. The continuous-wave laser beam, at a predetermined heat flux and a predetermined number of laser beam passes, mixes and displaces the plurality of colored polymer-based compositions, respectively, by way of melting and vaporizing them. Experiments showed a great accuracy of colors and designed patterns between the computer aided design (CAD) drawing and what was achieved after laser discoloration. It was found that lower values of power and speed provide sufficient energy and time to make a melt pool of colors and cause their vaporization from the surface. A detailed numerical simulation was performed to obtain a detailed understanding of the physics of laser interaction with paint using ABAQUS software. The comparative analysis indicated that the top layer of paint (including yellow and green colors) melted upon increasing cutting speed and employing one laser pass. For blue and red paints, two passes of lasers are required; in the case of red color, lower laser speed is also necessary to intensify the heat. This method can be applied for making art designs on each surface color because it is based on melting and vaporization using a laser.
    Matched MeSH terms: Computer-Aided Design
  5. Ibrahim MD, Amran SNA, Yunos YS, Rahman MRA, Mohtar MZ, Wong LK, et al.
    Appl Bionics Biomech, 2018;2018:7854321.
    PMID: 29853998 DOI: 10.1155/2018/7854321
    The skin of a fast swimming shark reveals riblet structures that help reduce the shark's skin friction drag, enhancing its efficiency and speed while moving in the water. Inspired by the structure of the shark skin denticles, our team has carried out a study as an effort in improving the hydrodynamic design of marine vessels through hull design modification which was inspired by this riblet structure of shark skin denticle. Our study covers on macroscaled design modification. This is an attempt to propose an alternative for a better economical and practical modification to obtain a more optimum cruising characteristics for marine vessels. The models used for this study are constructed using computer-aided design (CAD) software, and computational fluid dynamic (CFD) simulations are then carried out to predict the effectiveness of the hydrodynamic effects of the biomimetic shark skins on those models. Interestingly, the numerical calculated results obtained show that the presence of biomimetic shark skin implemented on the vessels give about 3.75% reduction of drag coefficient as well as reducing up to 3.89% in drag force experienced by the vessels. Theoretically, as force drag can be reduced, it can lead to a more efficient vessel with a better cruising speed. This will give better impact to shipping or marine industries around the world. However, it can be suggested that an experimental procedure is best to be conducted to verify the numerical result that has been obtained for further improvement on this research.
    Matched MeSH terms: Computer-Aided Design
  6. Abd Razak NA, Abu Osman NA, Gholizadeh H, Ali S
    Biomed Eng Online, 2014 Apr 23;13:49.
    PMID: 24755242 DOI: 10.1186/1475-925X-13-49
    BACKGROUND: The design and performance of a new development prosthesis system known as biomechatronics wrist prosthesis is presented in this paper. The prosthesis system was implemented by replacing the Bowden tension cable of body powered prosthesis system using two ultrasonic sensors, two servo motors and microcontroller inside the prosthesis hand for transradial user.

    METHODS: The system components and hand prototypes involve the anthropometry, CAD design and prototyping, biomechatronics engineering together with the prosthetics. The modeler construction of the system develop allows the ultrasonic sensors that are placed on the shoulder to generate the wrist movement of the prosthesis. The kinematics of wrist movement, which are the pronation/supination and flexion/extension were tested using the motion analysis and general motion of human hand were compared. The study also evaluated the require degree of detection for the input of the ultrasonic sensor to generate the wrist movements.

    RESULTS: The values collected by the vicon motion analysis for biomechatronics prosthesis system were reliable to do the common tasks in daily life. The degree of the head needed to bend to give the full input wave was about 45°-55° of rotation or about 14 cm-16 cm. The biomechatronics wrist prosthesis gave higher degree of rotation to do the daily tasks but did not achieve the maximum degree of rotation.

    CONCLUSION: The new development of using sensor and actuator in generating the wrist movements will be interesting for used list in medicine, robotics technology, rehabilitations, prosthetics and orthotics.

    Matched MeSH terms: Computer-Aided Design
  7. Ishak MI, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    Int J Oral Maxillofac Surg, 2012 Sep;41(9):1077-89.
    PMID: 22575179 DOI: 10.1016/j.ijom.2012.04.010
    The aim of this study was to compare two different types of surgical approaches, intrasinus and extramaxillary, for the placement of zygomatic implants to treat atrophic maxillae. A computational finite element simulation was used to analyze the strength of implant anchorage for both approaches in various occlusal loading locations. Three-dimensional models of the craniofacial structures surrounding a region of interest, soft tissue and framework were developed using computed tomography image datasets. The implants were modelled using computer-aided design software. The bone was assumed to be linear isotropic with a stiffness of 13.4 GPa, and the implants were assumed to be made of titanium with a stiffness of 110 GPa. Masseter forces of 300 N were applied at the zygomatic arch, and occlusal loads of 150 N were applied vertically onto the framework surface at different locations. The intrasinus approach demonstrated more satisfactory results and could be a viable treatment option. The extramaxillary approach could also be recommended as a reasonable treatment option, provided some improvements are made to address the cantilever effects seen with that approach.
    Matched MeSH terms: Computer-Aided Design*
  8. Hollister SJ, Lin CY, Lin CY, Schek RD, Taboas JM, Flanagan CL, et al.
    Med J Malaysia, 2004 May;59 Suppl B:131-2.
    PMID: 15468853
    Matched MeSH terms: Computer-Aided Design*
  9. Baharuddin MY, Salleh ShH, Zulkifly AH, Lee MH, Noor AM, A Harris AR, et al.
    PMID: 24484753 DOI: 10.1186/1471-2474-15-30
    Minimal available information concerning hip morphology is the motivation for several researchers to study the difference between Asian and Western populations. Current use of a universal hip stem of variable size is not the best option for all femur types. This present study proposed a new design process of the cementless femoral stem using a three dimensional model which provided more information and accurate analysis compared to conventional methods.
    Matched MeSH terms: Computer-Aided Design*
  10. Baig MR, Rajan G, Rajan M
    J Oral Implantol, 2009;35(6):295-9.
    PMID: 20017646 DOI: 10.1563/AAID-JOI-D-09-00012R1.1
    This article describes the rehabilitation of a completely edentulous patient using a milled titanium implant framework and cemented crowns. This combined approach significantly offsets unsuitable implant position, alignment, or angulation, while ensuring the easy retrievability, repair, and maintenance of the prosthesis. Hence, the dual advantage of cemented-retained crowns reproducing appropriate esthetics and function, irrespective of where the screw access openings are located in the substructure, can be obtained, along with the splinting effect and management of soft and hard tissue deficits achievable with a screw-retained framework.
    Matched MeSH terms: Computer-Aided Design*
  11. Abbasi MA, Anwar A, Rehman A, Siddiqui SZ, Rubab K, Shah SAA, et al.
    Pak J Pharm Sci, 2017 Sep;30(5):1715-1724.
    PMID: 29084694
    Heterocyclic molecules have been frequently investigated to possess various biological activities during the last few decades. The present work elaborates the synthesis and enzymatic inhibition potentials of a series of sulfonamides. A series of 1-arylsulfonyl-4-Phenylpiperazine (3a-n) geared up by the reaction of 1-phenylpiperazine (1) and different (un)substituted alkyl/arylsulfonyl chlorides (2a-n), under defined pH control using water as a reaction medium. The synthesized molecules were characterized by 1H-NMR, 13C-NMR, IR and EI-MS spectral data. The enzyme inhibition study was carried on α-glucosidase, lipoxygenase (LOX), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) enzymes supported by docking simulation studies and the IC50 values rendered a few of the synthesized molecules as moderate inhibitors of these enzymes where, the compound 3e exhibited comparatively better potency against α-glucosidase enzyme. The synthesized compounds showed weak or no inhibition against LOX, AChE and BChE enzymes.
    Matched MeSH terms: Computer-Aided Design*
  12. Rosli AN, Ahmad MR, Alias Y, Zain SM, Lee VS, Woi PM
    J Mol Model, 2014 Dec;20(12):2533.
    PMID: 25433601 DOI: 10.1007/s00894-014-2533-9
    Design of neutral receptor molecules (ionophores) for beryllium(II) using unsaturated carbonitrile models has been carried out via density functional theory, G3, and G4 calculations. The first part of this work focuses on gas phase binding energies between beryllium(II) and 2-cyano butadiene (2-CN BD), 3-cyano propene (3-CN P), and simpler models with two separate fragments; acrylonitrile and ethylene. Interactions between beryllium(II) and cyano nitrogen and terminal olefin in the models have been examined in terms of geometrical changes, distribution of charge over the entire π-system, and rehybridization of vinyl carbon orbitals. NMR shieldings and vibrational frequencies probed charge centers and strength of interactions. The six-membered cyclic complexes have planar structures with the rehybridized carbon slightly out of plane (16° in 2-CN BD). G3 results show that in 2-CN BD complex participation of vinyl carbon further stabilizes the cyclic adduct by 16.3 kcal mol(-1), whereas, in simpler models, interaction between beryllium(II) and acetonitrile is favorable by 46.4 kcal mol(-1) compared with that of ethylene. The terminal vinyl carbon in 2-CN BD rehybridizes to sp (3) with an increase of 7 % of s character to allow interaction with beryllium(II). G4 calculations show that the Be(II) and 2-CN BD complex is more strongly bound than those with Mg(II) and Ca(II) by 98.5 and 139.2 kcal mol(-1) (-1), respectively. QST2 method shows that the cyclic and acyclic forms of Be(II)-2-CN BD complexes are separated by 12.3 kcal mol(-1) barrier height. Overlap population analysis reveals that Ca(II) can be discriminated based on its tendency to form ionic interaction with the receptor models.
    Matched MeSH terms: Computer-Aided Design
  13. Zaman MR, Islam MT, Misran N, Yatim B
    ScientificWorldJournal, 2014;2014:831435.
    PMID: 24977230 DOI: 10.1155/2014/831435
    A radio frequency (RF) resonator using glass-reinforced epoxy material for C and X band is proposed in this paper. Microstrip line technology for RF over glass-reinforced epoxy material is analyzed. Coupling mechanism over RF material and parasitic coupling performance is explained utilizing even and odd mode impedance with relevant equivalent circuit. Babinet's principle is deployed to explicate the circular slot ground plane of the proposed resonator. The resonator is designed over four materials from different backgrounds which are glass-reinforced epoxy, polyester, gallium arsenide (GaAs), and rogers RO 4350B. Parametric studies and optimization algorithm are applied over the geometry of the microstrip resonator to achieve dual band response for C and X band. Resonator behaviors for different materials are concluded and compared for the same structure. The final design is fabricated over glass-reinforced epoxy material. The fabricated resonator shows a maximum directivity of 5.65 dBi and 6.62 dBi at 5.84 GHz and 8.16 GHz, respectively. The lowest resonance response is less than -20 dB for C band and -34 dB for X band. The resonator is prototyped using LPKF (S63) drilling machine to study the material behavior.
    Matched MeSH terms: Computer-Aided Design
  14. Mahyuddin NM, Russell G
    ScientificWorldJournal, 2014;2014:876435.
    PMID: 24782671 DOI: 10.1155/2014/876435
    Technology scaling relies on reduced nodal capacitances and lower voltages in order to improve performance and power consumption, resulting in significant increase in layout density, thus making these submicron technologies more susceptible to soft errors. Previous analysis indicates a significant improvement in SEU tolerance of the driver when the bias current is injected into the circuit but results in increase of power dissipation. Subsequently, other alternatives are considered. The impact of transistor sizes and temperature on SEU tolerance is tested. Results indicate no significant changes in Q(crit) when the effective transistor length is increased by 10%, but there is an improvement when high temperature and high bias currents are applied. However, this is due to other process parameters that are temperature dependent, which contribute to the sharp increase in Q(crit). It is found that, with temperature, there is no clear factor that can justify the direct impact of temperature on the SEU tolerance. Thus, in order to improve the SEU tolerance, high bias currents are still considered to be the most effective method in improving the SEU sensitivity. However, good trade-off is required for the low-swing driver in order to meet the reliability target with minimal power overhead.
    Matched MeSH terms: Computer-Aided Design
  15. Rosli AN, Bakar MA, Manan NS, Woi PM, Lee VS, Zain SM, et al.
    Sensors (Basel), 2013;13(10):13835-60.
    PMID: 24129020 DOI: 10.3390/s131013835
    Combined computational and experimental strategies for the systematic design of chemical sensor arrays using carbonitrile neutral receptors are presented. Binding energies of acetonitrile, n-pentylcarbonitrile and malononitrile with Ca(II), Mg(II), Be(II) and H⁺ have been investigated with the B3LYP, G3, CBS-QB3, G4 and MQZVP methods, showing a general trend H⁺ > Be(II) > Mg(II) > Ca(II). Hydrogen bonding, donor-acceptor and cation-lone pair electron simple models were employed in evaluating the performance of computational methods. Mg(II) is bound to acetonitrile in water by 12.5 kcal/mol, and in the gas phase the receptor is more strongly bound by 33.3 kcal/mol to Mg(II) compared to Ca(II). Interaction of bound cations with carbonitrile reduces the energies of the MOs involved in the proposed σ-p conjugated network. The planar malononitrile-Be(II) complex possibly involves a π-network with a cationic methylene carbon. Fabricated potentiometric chemical sensors show distinct signal patterns that can be exploited in sensor array applications.
    Matched MeSH terms: Computer-Aided Design
  16. Oshkour AA, Abu Osman NA, Yau YH, Tarlochan F, Abas WA
    Proc Inst Mech Eng H, 2013 Jan;227(1):3-17.
    PMID: 23516951
    This study aimed to develop a three-dimensional finite element model of a functionally graded femoral prosthesis. The model consisted of a femoral prosthesis created from functionally graded materials (FGMs), cement, and femur. The hip prosthesis was composed of FGMs made of titanium alloy, chrome-cobalt, and hydroxyapatite at volume fraction gradient exponents of 0, 1, and 5, respectively. The stress was measured on the femoral prosthesis, cement, and femur. Stress on the neck of the femoral prosthesis was not sensitive to the properties of the constituent material. However, stress on the stem and cement decreased proportionally as the volume fraction gradient exponent of the FGM increased. Meanwhile, stress became uniform on the cement mantle layer. In addition, stress on the femur in the proximal part increased and a high surface area of the femoral part was involved in absorbing the stress. As such, the stress-shielding area decreased. The results obtained in this study are significant in the design and longevity of new prosthetic devices because FGMs offer the potential to achieve stress distribution that more closely resembles that of the natural bone in the femur.
    Matched MeSH terms: Computer-Aided Design
  17. Ahmad MR, Nakajima M, Kojima M, Kojima S, Homma M, Fukuda T
    IEEE Trans Nanobioscience, 2012 Mar;11(1):70-8.
    PMID: 22275723 DOI: 10.1109/TNB.2011.2179809
    In this paper, single cells adhesion force was measured using a nanofork. The nanofork was used to pick up a single cell on a line array substrate inside an environmental scanning electron microscope (ESEM). The line array substrate was used to provide small gaps between the single cells and the substrate. Therefore, the nanofork could be inserted through these gaps in order to successfully pick up a single cell. Adhesion force was measured during the cell pick-up process from the deflection of the cantilever beam. The nanofork was fabricated using focused ion beam (FIB) etching process while the line array substrate was fabricated using nanoimprinting technology. As to investigate the effect of contact area on the strength of the adhesion force, two sizes of gap distance of line array substrate were used, i.e., 1 μm and 2 μm. Results showed that cells attached on the 1 μm gap line array substrate required more force to be released as compared to the cells attached on the 1 μm gap line array substrate.
    Matched MeSH terms: Computer-Aided Design
  18. Hashim Y, Sidek O
    J Nanosci Nanotechnol, 2013 Jan;13(1):242-9.
    PMID: 23646723
    This study is the first to demonstrate dimensional optimization of nanowire-complementary metal-oxide-semiconductor inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on both dimensions ratio and digital voltage level (Vdd). Diameter optimization reveals that when Vdd increases, the optimized value of (Dp/Dn) decreases. Channel length optimization results show that when Vdd increases, the optimized value of Ln decreases and that of (Lp/Ln) increases. Dimension ratio optimization reveals that when Vdd increases, the optimized value of Kp/Kn decreases, and silicon nanowire transistor with suitable dimensions (higher Dp and Ln with lower Lp and Dn) can be fabricated.
    Matched MeSH terms: Computer-Aided Design
  19. Cheung JPY, Cheung PWH, Shigematsu H, Takahashi S, Kwan MK, Chan CYW, et al.
    J Orthop Surg (Hong Kong), 2020 6 13;28(2):2309499020930291.
    PMID: 32529908 DOI: 10.1177/2309499020930291
    PURPOSE: To determine consensus among Asia-Pacific surgeons regarding nonoperative management for adolescent idiopathic scoliosis (AIS).

    METHODS: An online REDCap questionnaire was circulated to surgeons in the Asia-Pacific region during the period of July 2019 to September 2019 to inquire about various components of nonoperative treatment for AIS. Aspects under study included access to screening, when MRIs were obtained, quality-of-life assessments used, role of scoliosis-specific exercises, bracing criteria, type of brace used, maturity parameters used, brace wear regimen, follow-up criteria, and how braces were weaned. Comparisons were made between middle-high income and low-income countries, and experience with nonoperative treatment.

    RESULTS: A total of 103 responses were collected. About half (52.4%) of the responders had scoliosis screening programs and were particularly situated in middle-high income countries. Up to 34% obtained MRIs for all cases, while most would obtain MRIs for neurological problems. The brace criteria were highly variable and was usually based on menarche status (74.7%), age (59%), and Risser staging (92.8%). Up to 52.4% of surgeons elected to brace patients with large curves before offering surgery. Only 28% of responders utilized CAD-CAM techniques for brace fabrication and most (76.8%) still utilized negative molds. There were no standardized criteria for brace weaning.

    CONCLUSION: There are highly variable practices related to nonoperative treatment for AIS and may be related to availability of resources in certain countries. Relative consensus was achieved for when MRI should be obtained and an acceptable brace compliance should be more than 16 hours a day.

    Matched MeSH terms: Computer-Aided Design
  20. Farook TH, Jamayet NB, Asif JA, Din AS, Mahyuddin MN, Alam MK
    Sci Rep, 2021 04 19;11(1):8469.
    PMID: 33875672 DOI: 10.1038/s41598-021-87240-9
    Palatal defects are rehabilitated by fabricating maxillofacial prostheses called obturators. The treatment incorporates taking deviously unpredictable impressions to facsimile the palatal defects into plaster casts for obturator fabrication in the dental laboratory. The casts are then digitally stored using expensive hardware to prevent physical damage or data loss and, when required, future obturators are digitally designed, and 3D printed. Our objective was to construct and validate an economic in-house smartphone-integrated stereophotogrammetry (SPINS) 3D scanner and to evaluate its accuracy in designing prosthetics using open source/free (OS/F) digital pipeline. Palatal defect models were scanned using SPINS and its accuracy was compared against the standard laser scanner for virtual area and volumetric parameters. SPINS derived 3D models were then used to design obturators by using (OS/F) software. The resultant obturators were virtually compared against standard medical software designs. There were no significant differences in any of the virtual parameters when evaluating the accuracy of both SPINS, as well as OS/F derived obturators. However, limitations in the design process resulted in minimal dissimilarities. With further improvements, SPINS based prosthetic rehabilitation could create a viable, low cost method for rural and developing health services to embrace maxillofacial record keeping and digitised prosthetic rehabilitation.
    Matched MeSH terms: Computer-Aided Design
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