Muhd Nur Rahman Yahya
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Preferred name
Muhd Nur Rahman Yahya
Official Name
Muhd Nur Rahman, Yahya
Alternative Name
Yahya, Muhd Nur Rahman
Main Affiliation
Scopus Author ID
57210686015
Researcher ID
FYK-6865-2022

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  • Publication
    Analysis of temperature and relative humidity distributions in a dental treatment room at a government health clinic in Malaysia
    (Semarak Ilmu Publishing, 2025)
    Mohamad Nazrin Yahaya
    ;
    Zuradzman Mohamad Razlan
    ;
    Eswanto Eswanto
    ;
    Naoki Maruyama
    ;
    Anas Abdul Rahman
    ;
    Muhd Nur Rahman Yahya
    ;
    Shahriman Abu Bakar
    ;
    Muhammad Faiz Hilmi Rani
    This study investigates the vertical distribution of temperature and relative humidity within dental treatment rooms at a Government Type 3 Health Clinic in Gial Perlis, Malaysia, addressing a significant gap in the literature regarding environmental conditions in dental healthcare settings. Precise measurements were conducted at four specific heights 0.3 m, 1.0 m, 1.7 m, and 2.7 m utilizing calibrated digital thermometers with hygrometers to capture accurate environmental data. The collected data were analysed using Analysis of Variance (ANOVA) to assess the significance of variations across these levels. Results revealed statistically significant differences in both temperature and relative humidity (p < 0.05). At the uppermost level (2.7 m), the highest mean temperature of 22.1°C and a mean relative humidity of 68.2% were recorded, while the lowest level (0.3 m) exhibited the lowest mean temperature of 20.9°C and the highest mean relative humidity of 73.8%. Temperatures at the patient level (1.0 m and 1.7 m) averaged between 21.0 °C and 21.6°C, which is slightly below the optimal comfort range of 22°C to 26°C. These vertical gradients indicate that the existing HVAC systems may not be effectively regulating indoor conditions, potentially impacting patient comfort, the performance of temperature-sensitive dental materials, and the effectiveness of infection control measures due to altered aerosol behaviour. The findings underscore the necessity of optimizing HVAC designs to achieve uniform temperature and humidity distributions within dental treatment rooms. This research provides valuable insights for healthcare professionals and policymakers, emphasizing the importance of tailored environmental management strategies to enhance patient comfort, procedural outcomes, and safety in dental healthcare settings.
  • Publication
    A computational fluid dynamic analysis of prolonging survival in the microvascular vein grafting
    ( 2014)
    Muhd Nur Rahman Yahya
    A digital artery disease in the upper extremity is uncommon to happen but the revascularization procedure is still needed. As action taken, the surgical vein bypassing or vein interposition is performed. However, one or more internal diameters of the applied Reverse Saphenous Vein Graft (RSVG) are blocked and severely narrowed due to the irregular geometry formation such as internal diameter mismatched and over the length kink after the revascularization. In previous researches, the irregular geometry formation, the size discrepancy and bent in the vessel caused the abnormal blood flow and initiated the thrombosis. Furthermore, their previous works were also supported by clinical theory. The objective of this study is to investigate the effect of the blood flow on internal diameter mismatched and over the length kink of the RSVG models that relates to their long term survival. A Three-Dimensional Computational Fluid Dynamic (3D CFD) method is employed to investigate the velocity, the pressure gradient and the Wall Shear Stress (WSS) on ideal straight and irregular geometry of the RSVG models. For this research, the pulsatile laminar blood flow demonstrates non-hydraulically flow in irregular geometry of the vein graft models compared to an ideal straight model even in a steady state laminar blood flow test. As a conclusion, the results showed high value in the velocity, the pressure gradient and the WSS in the mismatch problem but low value in the velocity, the pressure gradient and the WSS in the over length kink problem. Any abnormal blood flow behavior will initiate the formation of the thrombosis and reduce the vein graft survival.
      7  24
  • Publication
    A comparative study of dual cylinders and triangle bluff bodies for piezoelectric energy harvesting
    (IOP Publishing, 2023)
    Mohd Nor Fakhzan Mohd Kazim
    ;
    Y J Zhe
    ;
    Zambri Harun
    ;
    Mohd Zaki Nuawi
    ;
    Mohammad Rasidi Rasani
    ;
    Muhd Nur Rahman Yahya
    The flow patterns behind tandem bluff bodies can be used to generate electricity in piezoelectric energy harvesters. The vortices and wakes that form behind the bluff bodies create a pressure differential, which can be used to deform a piezoelectric film. In this study, we investigated the performance of dual triangle and dual cylinder bluff bodies in tandem at varying Reynolds numbers, Re, and spacing ratios, D. We compared the flow patterns behind the two types of bluff bodies. Sixteen hot wire anemometers were placed at different locations to measure the velocity developed behind the dual bluff bodies in tandem. The results showed that the velocities behind the cylinder bluff bodies were initially higher than those behind the triangle bluff bodies at lower Re. This is because the cylinder bluff bodies create a more turbulent flow, which results in higher velocities at lower Re. The best distance between the two bluff bodies was 3D and 5D, where the output velocities were maximized at more than 12ms-1. However, for dual triangle, the velocities eventually became higher than those behind the cylinder bluff bodies at higher Re and lower separation ratios (1D and 2D). 3D was the best distance for triangle to produce a higher velocity pattern, and this was best observed when Re = 10k, which is the lowest inlet velocity set. The results of the experiments are expected to show that the dual triangle bluff bodies produce higher velocities than the dual triangle bluff bodies, which will lead to a higher amount of energy being harvested. The results show that the amount of energy harvested were increase with increasing Re and decreasing D. The information enhancement can be done with turbulence analysis which could lead to the development of more efficient and versatile piezoelectric energy harvester.
      1  10