Displaying publications 21 - 40 of 411 in total

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  1. Embracing diversity in user needs for affective design
    Khalid HM
    Appl Ergon, 2006 Jul;37(4):409-18.
    PMID: 16764817
    To develop product portfolios and affective design we need to understand the diversity in user needs. The challenge is how to predict what users want and how they will behave. One approach is to understand user emotions and affective needs, and predict successful product design that can match the needs. This paper discusses affect and its link to cognition. To provide a context, several theories are presented. A framework is described that incorporates characteristics of users, tasks, products, and use environment. The goal is to highlight the importance of emotions in enhancing the value of products. This research field, which we call Hedonomics, is new. There are many challenges in developing valid and reliable measurements of affect, which can influence human factors research as well as design.
    Matched MeSH terms: Equipment Design/psychology*
  2. Fulltext Design and Development of Micro-Power Generating Device for Biomedical Applications of Lab-on-a-Disc
    Joseph K, Ibrahim F, Cho J, Thio TH, Al-Faqheri W, Madou M
    PLoS One, 2015;10(9):e0136519.
    PMID: 26422249 DOI: 10.1371/journal.pone.0136519
    The development of micro-power generators for centrifugal microfluidic discs enhances the platform as a green point-of-care diagnostic system and eliminates the need for attaching external peripherals to the disc. In this work, we present micro-power generators that harvest energy from the disc's rotational movement to power biomedical applications on the disc. To implement these ideas, we developed two types of micro-power generators using piezoelectric films and an electromagnetic induction system. The piezoelectric-based generator takes advantage of the film's vibration during the disc's rotational motion, whereas the electromagnetic induction-based generator operates on the principle of current generation in stacks of coil exposed to varying magnetic flux. We have successfully demonstrated that at the spinning speed of 800 revolutions per minute (RPM) the piezoelectric film-based generator is able to produce up to 24 microwatts using 6 sets of films and the magnetic induction-based generator is capable of producing up to 125 milliwatts using 6 stacks of coil. As a proof of concept, a custom made localized heating system was constructed to test the capability of the magnetic induction-based generator. The heating system was able to achieve a temperature of 58.62 °C at 2200 RPM. This development of lab-on-a-disc micro power generators preserves the portability standards and enhances the future biomedical applications of centrifugal microfluidic platforms.
    Matched MeSH terms: Equipment Design*
  3. Modeling and Simulation of Two Wheelchair Accessories for Pushing Doors
    Abdullah SJ, Shaikh Mohammed J
    Assist Technol, 2018;30(4):165-175.
    PMID: 28346064 DOI: 10.1080/10400435.2017.1293193
    Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.
    Matched MeSH terms: Equipment Design/methods*
  4. Fulltext Modeling of a viscoelastic damper and its application in structural control
    Mehrabi MH, Suhatril M, Ibrahim Z, Ghodsi SS, Khatibi H
    PLoS One, 2017;12(6):e0176480.
    PMID: 28570657 DOI: 10.1371/journal.pone.0176480
    Conventional seismic rehabilitation methods may not be suitable for some buildings owing to their high cost and time-consuming foundation work. In recent years, viscoelastic dampers (VEDs) have been widely used in many mid- and high-rise buildings. This study introduces a viscoelastic passive control system called rotary rubber braced damper (RRBD). The RRBD is an economical, lightweight, and easy-to-assemble device. A finite element model considering nonlinearity, large deformation, and material damage is developed to conduct a parametric study on different damper sizes under pushover cyclic loading. The fundamental characteristics of this VED system are clarified by analyzing building structures under cyclic loading. The result show excellent energy absorption and stable hysteresis loops in all specimens. Additionally, by using a sinusoidal shaking table test, the effectiveness of the RRBD to manage the response displacement and acceleration of steel frames is considered. The RRBD functioned at early stages of lateral displacement, indicating that the system is effective for all levels of vibration. Moreover, the proposed damper shows significantly better performance in terms of the column compression force resulting from the brace action compared to chevron bracing (CB).
    Matched MeSH terms: Equipment Design*
  5. Fulltext Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags
    Rokunuzzaman M, Islam MT, Rowe WS, Kibria S, Jit Singh M, Misran N
    PLoS One, 2016;11(8):e0161293.
    PMID: 27533470 DOI: 10.1371/journal.pone.0161293
    A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919-923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for 'place and tag' application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP).
    Matched MeSH terms: Equipment Design/instrumentation*
  6. Changes in oral functions and speech when using custom-fitted mouthguards: An uncontrolled before-and-after study
    Mat Zainal MK, Liew AKC, Abdullah D, Soo E, Abdul Hamid B, Ramlee RAM
    Dent Traumatol, 2024 Aug;40(4):460-469.
    PMID: 38459669 DOI: 10.1111/edt.12939
    BACKGROUND/AIM: Mouthguards are crucial for protecting athletes against orofacial injuries, yet concerns persist regarding their potential impact on oral functions. This study aimed to investigate the effects of sports mouthguards on oral functions and speech over time.

    MATERIAL AND METHODS: Thirty national rugby players received custom-fitted mouthguards. Questionnaire responses and speech recordings were collected before mouthguard use and at various intervals after using mouthguards: immediately, 1 week, 2 month, and 6 months. Spectrographic analysis was performed to measure voice onset time (VOT) for /p, b, t, d/ phonemes. Questionnaire responses were assessed with Friedman's test, while VOT changes were examined using one-way repeated measure analysis of variance.

    RESULTS: Compliance with mouthguard use improved during training and competitions, with consistent wear reported during matches. Over time, speaking difficulties and lisping decreased significantly (p 

    Matched MeSH terms: Equipment Design*
  7. Fulltext Improving the dynamic characteristics of body-in-white structure using structural optimization
    Yahaya Rashid AS, Ramli R, Mohamed Haris S, Alias A
    ScientificWorldJournal, 2014;2014:190214.
    PMID: 25101312 DOI: 10.1155/2014/190214
    The dynamic behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process.
    Matched MeSH terms: Equipment Design
  8. Fulltext Low-cost dielectric substrate for designing low profile multiband monopole microstrip antenna
    Ahsan MR, Islam MT, Habib Ullah M, Arshad H, Mansor MF
    ScientificWorldJournal, 2014;2014:183741.
    PMID: 25136648 DOI: 10.1155/2014/183741
    This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm(2) radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53-2.89 GHz) and 440 MHz (3.47-3.91 GHz) for WiMAX and 1550 MHz (6.28-7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively.
    Matched MeSH terms: Equipment Design
  9. Fulltext Experimental investigation of a wing-in-ground effect craft
    Tofa MM, Maimun A, Ahmed YM, Jamei S, Priyanto A, Rahimuddin
    ScientificWorldJournal, 2014;2014:489308.
    PMID: 24701170 DOI: 10.1155/2014/489308
    The aerodynamic characteristics of the wing-in-ground effect (WIG) craft model that has a noble configuration of a compound wing was experimentally investigated and Universiti Teknologi Malaysia (UTM) wind tunnel with and without endplates. Lift and drag forces, pitching moment coefficients, and the centre of pressure were measured with respect to the ground clearance and the wing angle of attack. The ground effect and the existence of the endplates increase the wing lift-to-drag ratio at low ground clearance. The results of this research work show new proposed design of the WIG craft with compound wing and endplates, which can clearly increase the aerodynamic efficiency without compromising the longitudinal stability. The use of WIG craft is representing an ambitious technology that will help in reducing time, effort, and money of the conventional marine transportation in the future.
    Matched MeSH terms: Equipment Design
  10. Fulltext Analysis of resonance response performance of C-band antenna using parasitic element
    Zaman MR, Islam MT, Misran N, Mandeep JS
    ScientificWorldJournal, 2014;2014:131374.
    PMID: 24895643 DOI: 10.1155/2014/131374
    Analysis of the resonance response improvement of a planar C-band (4-8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency.
    Matched MeSH terms: Equipment Design
  11. Fulltext Inverted S-shaped compact antenna for X-band applications
    Samsuzzaman M, Islam MT
    ScientificWorldJournal, 2014;2014:604375.
    PMID: 24895656 DOI: 10.1155/2014/604375
    A novel probe-fed compact inverted S-shaped multifrequency patch antenna is designed. By employing two rectangular slots that change the conventional rectangular patch into an inverted S-shaped patch, the antenna is able to operate in triple frequency in the X-band. The performance criteria of the proposed design have been experimentally verified by fabricating a printed prototype. The measured results show that the -10 dB impedance bandwidth of the proposed antenna at lower band is 5.02% (8.69-9.14 GHz), at middle band is 9.13% (10.47-11.48 GHz), and at upper band is 3.79% (11.53-11.98 GHz). Two elliptical slots are introduced in the ground plane to increase the peak gain. The antenna is excited by a simple probe feeding mechanism. The overall antenna dimension is  0.52λ × 0.60λ × 0.046λ at a lower resonance frequency of 9.08 GHz. The antenna configuration and parametric investigation are conducted with the help of the high frequency structural simulator, and a good agreement is achieved between the simulated and measured data. The stable gain, omnidirectional radiation pattern, and consistent radiation efficiency in the achieved operating band make the proposed antenna a suitable candidate for X-band applications.
    Matched MeSH terms: Equipment Design
  12. Fulltext Gain enhancement of a multiband resonator using defected ground surface on epoxy woven glass material
    Alam MS, Islam MT, Arshad H
    ScientificWorldJournal, 2014;2014:159468.
    PMID: 24883354 DOI: 10.1155/2014/159468
    A multiband microstrip resonator is proposed in this study which is realized through a rectangular radiator with embedded symmetrical rectangular slots in it and a defected ground surface. The study is presented with detailed parametric analyses to understand the effect of various design parameters. The design and analyses are performed using the FIT based full-wave electromagnetic simulator CST microwave studio suite. With selected parameter values, the resonator showed a peak gain of 5.85 dBi at 5.2 GHz, 6.2 dBi at 8.3 GHz, 3.9 dBi at 9.5 GHz, 5.9 dBi at 12.2 GHz, and 4.7 dBi at 14.6 GHz. Meanwhile, the main lobe magnitude and the 3 dB angular beam width are 6.2 dBi and 86°, 5.9 dBi and 53.7°, 8.5 dBi and 43.9°, 8.6 dBi and 42.1°, and 4.7 dBi and 30.1°, respectively, at the resonant frequencies. The overall resonator has a compact dimension of 0.52λ  × 0.52λ  × 0.027λ at the lower resonant frequency. For practical validation, a lab prototype was built on a 1.6 mm thick epoxide woven glass fabric dielectric material which is measured using a vector network analyzer and within an anechoic chamber. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband resonator design.
    Matched MeSH terms: Equipment Design
  13. Fulltext Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design
    Ahsan MR, Islam MT, Ullah MH, Singh MJ, Ali MT
    PLoS One, 2015;10(5):e0127185.
    PMID: 26018795 DOI: 10.1371/journal.pone.0127185
    A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11
    Matched MeSH terms: Equipment Design
  14. Fulltext Design and Experimental Evaluation of Modified Square Loop Feeding for UHF RFID Tags
    Rokunuzzaman M, Islam MT, Arshad H, Jit Singh M, Misran N
    PLoS One, 2015;10(7):e0132530.
    PMID: 26177376 DOI: 10.1371/journal.pone.0132530
    This paper addresses the performance evaluation of a modified square loop antenna design for UHF RFID applications that is excited through a narrow feed line connected to a square loop, an impedance matching network. The square loop dimensions are modified to reach a conjugate impedance matching. A gap is fixed between the feed-lines to link the chip. To achieve impedance matching, the structures of the feed-line are optimized accordingly. In addition, the antenna consists of a straightforward geometry. An 11.9-meter maximum read range is achieved using a compact size of 80 × 44 mm2 and 3.2 W for the effective isotropic radiated power. Additional findings reveal that the proposed tag antenna is able to provide a stable resonance response in the near field of a large metallic surface.
    Matched MeSH terms: Equipment Design
  15. Adjustable length tracheostomy tube for the morbidly obese and thick neck patient: a prototype
    Lim PV, Raman R
    Otolaryngol Head Neck Surg, 2001 Jan;124(1):56-7.
    PMID: 11228454
    Matched MeSH terms: Equipment Design
  16. Self-retaining ear speculum: Thudicum design
    Raman R, Subramaniam KN, Dahalil MB
    Otolaryngol Head Neck Surg, 1999 Jul;121(1):157.
    PMID: 10388900
    Matched MeSH terms: Equipment Design
  17. Fulltext Experimental Breast Phantom Imaging with Metamaterial-Inspired Nine-Antenna Sensor Array
    Islam MT, Samsuzzaman M, Islam MT, Kibria S
    Sensors (Basel), 2018 Dec 14;18(12).
    PMID: 30558191 DOI: 10.3390/s18124427
    An experimental system for early screening of a breast tumor is presented in this article. The proposed microwave imaging (MI) system consists of a moveable array of nine improved negative-index metamaterial (MTM)-loaded ultrawideband (UWB) antenna sensor with incorporation of a corresponding SRR (split-ring resonator) and CLS (capacitively loaded strip) structure, in a circular array, the stepper motor-based array-mounting stand, the adjustable phantom hanging platform, an RF switching system to control the receivers, and a personal computer-based signal processing and image reconstruction unit using MATLAB. The improved antenna comprises of four-unit cells along one axis, where an individual unit cell integrates a balancing SRR and CLS pair, which makes the antenna radiation omnidirectional over the operating frequencies. The electrical dimensions of this proposed antenna are 0.28λ × 0.20λ × 0.016λ, measured at the lowest operating frequency of 2.97 GHz as the operating bandwidth of this is in between 2.97⁻15 GHz (134.82% bandwidth), with stable directional radiation pattern. SP8T 8 port switch is used to enable the eight receiver antennas to sequentially send a 3⁻8.0 GHz microwave signal to capture the backscattered signal by MATLAB software. A low-cost realistic homogeneous breast phantom with tumor material is developed and measured to test the capability of the imaging system to detect the breast tumors. A post-processing delay-multiply-and-sum (DMAS) algorithm is used to process the recorded backscatter signal to get an image of the breast phantom, and to accurately identify the existence and located area of multiple breast tumor tissues.
    Matched MeSH terms: Equipment Design
  18. Fulltext Pressure Sensor System for Customized Scoliosis Braces
    Fuss FK, Ahmad A, Tan AM, Razman R, Weizman Y
    Sensors (Basel), 2021 Feb 06;21(4).
    PMID: 33562166 DOI: 10.3390/s21041153
    Hard-shell thoracolumbar sacral orthoses (TLSOs) are used for treating idiopathic scoliosis, a deformation of the spine with a sideways curvature. The pressure required inside the TLSO for ideal corrective results remains unclear. Retrofitting TLSOs with commercially available pressure measurement systems is expensive and can only be performed in a laboratory. The aim of this study was to develop a cost-effective but accurate pressure sensor system for TLSOs. The sensor was built from a piezoresistive polymer, placed between two closed-cell foam liners, and evaluated with a material testing machine. Because foams are energy absorbers, the pressure-conductance curve was affected by hysteresis. The sensor was calibrated on a force plate with the transitions from loading to unloading used to establish the calibration curve. The root mean square error was 12% on average within the required pressure range of 0.01-0.13 MPa. The sensor reacted to the changing pressure during breathing and different activities when tested underneath a chest belt at different tensions. The peak pressure reached 0.135 MPa. The sensor was further tested inside the scoliosis brace during different activities. The measured pressure was 0.014-0.124 MPa. The results from this study enable cheaper and mobile systems to be used for clinical studies on the comfort and pressure of braces during daily activities.
    Matched MeSH terms: Equipment Design
  19. Fulltext Ultralow Profile, Low Passive Intermodulation, and Super-Wideband Ceiling Mount Antennas for Cellular and Public Safety Distributed Antenna Systems
    Ng KJ, Islam MT, Alevy AM, Mansor MF
    Sensors (Basel), 2020 Apr 26;20(9).
    PMID: 32357426 DOI: 10.3390/s20092456
    This paper presents an ultralow profile, low passive intermodulation (PIM), and super-wideband in-building ceiling mount antenna that covers both the cellular and public safety ultra high frequency (UHF) band for distributed antenna system (DAS) applications. The proposed antenna design utilizes a modified 2-D planar discone design concept that is miniaturized to fit into a small disc-shaped radome. The 2-D planar discone has an elliptical-shaped disc monopole and a bell-shaped ground plane, a stub at the shorting path, with asymmetrical structure and an additional proximity coupling patch to maximize the available electrical path to support the 350 MHz band range. The proposed design maximizes the radome area with a reduction of about 62% compared to similar concept type antennas. Besides, the proposed design exhibits an improved radiation pattern with null reduction compared to a typical dipole/monopole when lies at the horizontal plane. A prototype was manufactured to demonstrate the antenna performance. The VSWR and radiation pattern results agreed with the simulated results. The proposed antenna achieves a band ratio of 28.57:1 while covering a frequency range of 350-10,000 MHz. The measured passive intermodulation levels are better than -150 dBc (2 × 20 Watts) for 350, 700 and 1920 MHz bands.
    Matched MeSH terms: Equipment Design
  20. Fulltext A Fluidics-Based Double Flexural Membrane Piezoelectric Micromachined Ultrasonic Transducer (PMUT) for Wide-Bandwidth Underwater Acoustic Applications
    Ahmad KA, Rahman MFA, Zain KAM, Haron MN, Manaf AA
    Sensors (Basel), 2021 Aug 19;21(16).
    PMID: 34451023 DOI: 10.3390/s21165582
    In acoustic receiver design, the receiving sensitivity and bandwidth are two primary parameters that determine the performance of a device. The trade-off between sensitivity and bandwidth makes the design very challenging, meaning it needs to be fine-tuned to suit specific applications. The ability to design a PMUT with high receiving sensitivity and a wide bandwidth is crucial to allow a wide spectrum of transmitted frequencies to be efficiently received. This paper presents a novel structure involving a double flexural membrane with a fluidic backing layer based on an in-plane polarization mode to optimize both the receiving sensitivity and frequency bandwidth for medium-range underwater acoustic applications. In this structure, the membrane material and electrode configuration are optimized to produce good receiving sensitivity. Simultaneously, a fluidic backing layer is introduced into the double flexural membrane to increase the bandwidth. Several piezoelectric membrane materials and various electrode dimensions were simulated using finite element analysis (FEA) techniques to study the receiving performance of the proposed structure. The final structure was then fabricated based on the findings from the simulation work. The pulse-echo experimental method was used to characterize and verify the performance of the proposed device. The proposed structure was found to have an improved bandwidth of 56.6% with a receiving sensitivity of -1.8864 dB rel 1 V µPa. For the proposed device, the resonance frequency and center frequency were 600 and 662.5 kHz, respectively, indicating its suitability for the targeted frequency range.
    Matched MeSH terms: Equipment Design
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