Browsing by Author "Ali, Hassan"

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    Development of affordable hot box calorimeter to determine the U-value of inhomogeneous building material
    (Elsevier, 2023-07-11) Alqahtani, Saad; Muhammad Ali, Hafiz; Farukh, Farukh; Kandan, Karthikeyan; Ali, Hassan
    In recent years, the use of three-dimensional printing to create construction components has advanced quickly; it is possible now to simplify construction, increase speed, and lower cost while using natural resources responsibly. It also allows us to use recycled material to produce building envelopes while increasing design flexibility. However, the thermal performance of building materials must be characterized to achieve the necessary energy efficiency of the building envelopes. This study aims to develop, produce, and calibrate a hot box calorimeter at a reasonable price for thermal testing components building envelope. The heat loss through these components using a hot box can be measured in a lab to get an idea of the thermal performance of the building envelopes. In order to evaluate and analyze the thermal performance of various 3D-printed building brick samples made in the labs, this study explains the design and creation of an inexpensive hot box. The hot box can conduct a conventional thermal experiment, which involves monitoring heat flux, surface temperatures, and air temperatures. The testing process, instrumentation, test conditions, and validation of the new metering box are all covered in the article. The U-value of the brand-new lattice-based 3D printed building blocks was afterward determined using the validated new hot box. It was observed that the U-values values of 1.04 W/m2.K and 0.99 W/m2.K, respectively, for small components utilizing developed hot box and larger lattice panels using commercial equipment, with a maximum variance of 5%. It highlights the dependability of the hot box apparatus, which is also made affordable to operate by using less material for specimen preparation and less energy to maintain the temperature in the hot and cold chambers. Its small size also makes setup and thermal testing of construction materials simple.
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    Drilling resistance: A method to investigate bone quality
    (Faculty of Mechanical Engineering, Wroclaw University of Technology, 2017-03) Lughmani, W. A.; Farukh, Farukh; Bouazza-Marouf, K.; Ali, Hassan
    Purpose: Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. Methods: This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. Results: The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r2 = 0.93 for pig bones and r2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. Conclusions: The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.
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    ItemOpen Access
    Effect of Condensate Flow Rate on Retention Angle on Horizontal Low-Finned Tubes
    (National Library of Serbia, 2016-08-29) Ali, Hafiz Muhammad; Ali, Hassan; Ali, Muhammad; Imran, Shahid; Kamran, Muhammad Sajid; Farukh, Farukh
    The paper reports experimental results using simulated condensation on eight horizontal integral finned tubes with different fin spacing but same root diameter. Condensation was simulated with low approaching zero vapor velocity of condensate using three liquids (water, ethylene glycol and R141b) supplied to the tube via small holes between the fins along the top of the tubes. Controlling parameters of the investigation were fin spacing of condensation tubes, flow rate of condensate and surface tension to density ratio of the condensate. The results indicate that the retention angle (measured from the top of the tube to the position where the inter-fin space is completely filled with liquid) increases with the increase in fin spacing. Also, retention angle increases as the density of the condensate increases but retention angle decreases with increase in surface tension. Interesting finding is seen as retention angle remains constant with increase in condensate flow rate, starting from very low (nearly zero) flow rate to the flow rate at which the tube gets fully flooded. The critical flow rate for eight tubes of defined fin density against three working fluids is measured. Results obtained from simulated condensation for almost zero condensate velocity are in good agreement with earlier data and theoretical model for retention angle on such tubes.
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    ItemOpen Access
    Key design features of multi vacuum glazing for windows: A review
    (Thermal Science, 2016-02-21) Ali, Hassan; Hayat, Nasir; Farukh, Farukh; Imran, Shahid; Kamran, Muhammad Sajid; Ali, Hafiz Muhammad
    The use of vacuum glazed windows is increasing due to their application in modern building design. Among various types of vacuum glazed windows reported in literature, thermal transmittance of single glass sheet (conventional window) i.e 6 W/m2k is reduced by 66 and 77% using air filled double glazed and air filled triple glazed windows respectively. Using low emittance coatings thermal transmittance of double glazed windows is reduced by 53%, however it offsets the visibility by reducing light transmittance by 5%. Stresses due to temperature/pressure gradients if not eliminated may lead to reduction in service life of vacuum glazed windows. Vacuum created between the glass sheets is used to reduce conductive heat transfer. Degradation in the vacuum is caused by number of factors such as, permeation of gaseous molecules through glass sheets, leakage through sealing, thermal/optical desorption and photo-fragmentation of organic species have been critically reviewed and future trends are outlined.