volume-17-Issue 2 (2020)
Latest Articles
Monitoring of temporal trend of atmospheric metals by moss Hypnum cupressiforme Hedw in Jammu (India)
IJTEE, volume-17, Issue 2 (2020) , PP 121 - 132
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.006
by Dinesh K. Saxena, Sachin Agarwal, A Saxena , Seema Kodesia from Department of Botany, Bareilly College, Bareilly, India. University of Waterloo, Canada, Research Scholar Environmental Sciences, IGNOU, New Delhi
Abstract: Atmospheric pollutants, such as metals, are extremely variable in space and time and it is cumbersome and expensive to deduce detailed information over a vast area using traditional instruments. Consequently, a cost-effective bio-monitor was preferred in the present study to analyze the atmospheric metal load. For this purpose, a moss Hypnum cupressiforme Hedw was inducted amongst moss species available to evaluate the intensity and trend of atmospheric deposition of Zn, Cu, Cd, and Pb in Jammu in the state of Jammu and Kashmir, India for a period of three years, 2014- 2016. The biomonitoring experimentation was performed by transplanting moss bags prepared from Hypnum cupressiforme, after validating its tolerance against metals using a photosynthetic efficiency analyzer in the field. Moss Hypnum cupressiforme Hedw exposed seasonally, covering summer, monsoon, and winter periods, upon the analysis provided time-integrated patterns of metal bioavailability at the study sites. An attempt was made to compare the seasonal variations during the three years of study and findings exhibited significant seasonal variations in metal. The gradient of the metal load was in the order of Cu>Cd>Zn>Pb. The total average percentage increase in the metals under consideration, Zn, Pb, Cu, and Cd, was 40%, 37%,79%, and 76%, respectively during three subsequent years. It is worth mentioning here that biomonitoring studies on atmospheric metals have never been explored for this region. read more... read less...
Keywords: Biomonitoring, atmospheric metals, moss bag transplants, temporal trend, Hypnum cupressiforme
Modelling of Hearing Aid’s Digital Signal Processor
IJTEE, volume-17, Issue 2 (2020) , PP 115 - 119
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.005
by Suad Abdulkareem, Isam Janajreh from Khalifa University, Abu Dhabi, UAE
Abstract: According to the World Health Organization (WHO), hearing loss (HL) is one of the six key contributors to worldwide disease rates. It is becoming a critical issue in society, not just affecting the aging population, but also negatively impacting young people who are spending more of their spare time performing activities that expose them to excessive noise levels. In this research, we intend to design a filter as a signal processing system in a hearing aid (HA). MATLAB is used to model the digital filter structure, while Simulink is used to capture the entire design. This study examines current critical concerns in hearing aid research from the perspectives of a variety of disciplines. The study proposes a filter and signal processor model based on hearing aid experience, but first, it provides an audiogram for numerous examples to determine if the suggested model would suit or not. The work thus provides an effective compensation of missed high-frequency sounds response in patient hearing by the digital signal processor read more... read less...
Keywords: Hearing Aid, Simulink, Hearing Filter
Geometric Optimization of a Gas Turbine Blade Cooling Passage using CFD
IJTEE, volume-17, Issue 2 (2020) , PP 105 - 114
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.004
by Ussama Ali , Muhammad Sajid Kamran from Department of Mechanical Engineering, University of Engineering and Technology, Lahore, 54890, Pakistan
Abstract: This work focuses on the rib-turbulated cooling which is a category of impingement cooling and aims at optimizing the geometry of rib-roughened cooling passage of a gas turbine blade. CFD analysis is carried out using Ansys/Fluent to solve the steady RANS equations. Computational domain consists of a long rectangular channel with the length of the channel being 9 times its height. Ratios of rib width, rib height and rib pitch to hydraulic diameter of the channel are taken as 0.1, 0.1 and 1.2, respectively. Numerical simulations are performed to analyze the performance of various rib shapes for Reynolds number, based upon the hydraulic diameter, in a range of 5000 to 50,000. Uniform heat flux of 800 W/m2 is applied to the ribbed wall. Incompressible air is used as the cooling fluid. Turbulent flow conditions are applied to the channel geometry with k-ω turbulence model. The effect of rib cross-section and rib pitch to rib width ratio on the heat transfer and friction factor is observed. The 2D CFD analysis revealed that the presence of ribs has significant effect on thermo-hydraulic performance of the cooling channel. Introducing square ribs in a smooth channel caused the Nusselt number to increase by two-folds. The highest value of Nusselt number was achieved by incorporating right-angle triangular ribs which caused the Nusselt number to increase by further 8%, as compared to the square ribs, and an increase in friction factor of 2.5%. The lowest value of friction factor was observed in semicircular ribs (2.95% less than the square ribs), however, the Nusselt number also decreased by 1.5%, as compared to square ribs. Decreasing rib pitch to rib width ratio increased both the Nusselt number and friction factor for all the cases. For square ribs, decreasing this ratio from 15 to 9 resulted in the rise of Nusselt number by 50% and increase in friction factor by 54%. read more... read less...
Keywords: Gas turbine blade cooling, Obstructed flow, Heat transfer enhancement, Turbulators, Ribbed channel
Effect of geometric aspect ratio and orifice length on the sound pressure level of a Helmholtz resonator
IJTEE, volume-17, Issue 2 (2020) , PP 99 - 104
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.003
by Mubarak Yakubu, Isam Janajreh from Khalifa University, Abu Dhabi, United Arab Emirates, Khalifa University, Abu Dhabi, United Arab Emirates
Abstract: The acoustic performance of a typical Helmholtz resonator is important for optimizing sound absorption coefficient. The acoustic impedance of the Helmholtz resonator varies with different geometric features. As such, various studies have been conducted to investigate some parametric effects like neck length, extended neck, orifice size, cavity size and glazing flow speed. In this study, we explore, numerically, the effect of cavity shape and geometric aspect ratios among other features. We determined the optimum geometric shapes, dimension and flow condition for better sound absorption of the Helmholtz resonator. read more... read less...
Keywords: Helmholtz resonator, transmission loss, acoustic impedance, resonance frequency
Analysis and Synthesis of Electrocardiogram (ECG) using Fourier and Wavelet Transform
IJTEE, volume-17, Issue 2 (2020) , PP 85 - 97
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.002
by Mohammed Basheer Mohiuddin Isam Janajreh from Khalifa University, Abu Dhabi, United Arab Emirates
Abstract: Electrocardiogram (ECG) is the study of the electrical signals of the human heart that are generated by the pumping action of the heart caused by the polarization and depolarization of the nodes of the heart. These signals must be interpreted with great accuracy and efficiency as they are paramount in prognosis and subsequent diagnosis of the condition of the patient. The goal of this project is to analyze the ECG signals following Fourier and Wavelet transforms, and to highlight and demonstrate the advantages of the Wavelet transform. Firstly, it involves simulating the temporal digital ECG signal and explaining the signal constituents, i.e., P, Q, R, S, T waves while staying in the time domain. Secondly, the ECG signal will be transferred into the frequency domain for quick, fast, and compressed analysis and carry out signal processing using Fourier analysis and highlight the pros and cons of this technique. Thirdly, wavelet analysis will be explored and demonstrated to mitigate the shortcoming of the former tool, i.e., Fourier. At this stage, various ECG signals, mimicking abnormalities, will be analyzed. This work will highlight the effectiveness of wavelet analysis as a tool to examine ECG signals. This work, hence, will entail, comparison of both transformation methods by utilizing the computational power of MATLAB. read more... read less...
Keywords: ECG, Fourier transform, Hann window, Wavelet transform, Daubechies, Symlet
Comparative study for Active Noise Cancellation using Adaptive filtering and Standing wave pattern
IJTEE, volume-17, Issue 2 (2020) , PP 73 - 84
Published: 08 Dec 2020
DOI: 10.5383/ijtee.17.02.001
by Ahmad Abubakar, Isam Janajreh from from Khalifa University of Science and Technology, Abu-Dhabi, United Arab Emirate
Abstract: Noise pollution is one of the most fundamental challenges facing our environment, causes health problem, communication inefficiency and degrade the performance of works due to lack of concentration, thus, mitigating this impact becomes an unavoidable requirement of time to protect people's health and the environment. This noise may originate from several sources including industrial machinery, system parts wear out, and adjacent environmental acoustics. To mitigate this noise effect, an Active Noise Cancellation (ANC) headphone is achieved by two effective techniques; Adaptive filtering and Standing wave phenomenon. In this work, an ANC system is designed using both adaptive filtering and standing wave techniques, the former one basically utilizes single-channel feedforward whereas the latter one utilizes both single-channel feedforward and feedback control. LMS adaptive filter algorithm is the basic component of the designed ANC headphone. For simulation, a noise-free signal will be used as the desired audio signal and a gaussian distributed noise as the unwanted noise signal, these are combined to form noise corrupted speech signal. Propose algorithms performance were evaluated based on the ability to mitigate effects of different frequency broad-band noise signals and of different Noise to Signal ratio. Evaluation measures used are; convergence rate and noise reduction in dB. Result reveals ANC headphone using standing wave technique has better performance at mitigating noise frequency below 800Hz, with low SNR than Adaptive filtering. However, at higher frequencies above 1000Hz, ANC headphone using Adaptive filtering has good performance of masking high frequencies up to 22dB. read more... read less...
Keywords: Active noise cancellation, Adaptive filtering, standing wave pattern, system identification, feedforward and feedback control
Automatic Domestic Stove Using Olive Cake Fuel
IJTEE, volume-17, Issue 2 (2020) , PP 67 - 72
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.008
by Jamil Al Asfar, Laith Mazahreh from Jamil Al Asfar, The University of Jordan, Amman, Jordan , Laith Mazahreh, Ministry of Energy and Mineral Resources, Amman, Jordan
Abstract: Desertification is considered one of the main problems that concerns mankind. Wood stoves and fireplaces mainly use wood as the main source of energy, which would lead to desertification and global warming. This paper presents the design of a domestic automatic stove that primary uses olive cake as the major source of energy. Moreover, a prototype of the theoretical model was built, and experimentally tested for 65 minutes. The efficiency of the prototyped model reached a value of 56.25% read more... read less...
Keywords: Olive Cake, Heating System, Biomass, Biofuels, Automatic.
Damage Identification of HAWT Blade using Ordinary Linear Kriging Method and Variation of Blade’s Modal Parameters
IJTEE, volume-17, Issue 2 (2020) , PP 59 - 66
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.007
by Ameen El-Sinawi, Mohammed Awadallah, Isam Janajreh from Mechanical Engineering Department, Khalifa University of Science and Technology, Masdar Institute, PO Box 54224, Masdar City, Abu Dhabi, United Arab Emirates
Abstract: Wind turbine blades operate in a harsh environment causing them to always be susceptible to damage. Variable wind loading, debris impact, and thermal gradient, among other factors, can cause damage to the blades. Detection of blade damage at early stages can prevent massive cost associated with turbine down-time and blade replacement. In this work, a vibration-based method is presented to detect damage at early stages. The presented method takes advantage of the effect of crack on modal parameters of the blade’s vibration. Finite element model (FEA) is constructed for both healthy and damage blade to study that effect. Power spectral density (PSD) plots of the blade’s vibration before and after damage are compared and the changes in the resonant modal amplitude’s frequencies are identified. To minimize the number accelerometers needed to monitor the health of the blade and without compromising the accuracy of damage predictions, ordinary kriging method is used to predict cracks in the blade’s structure. Kriging uses modal parameter data, experimental or otherwise, to estimate damage location on the blade. It creates a map of damage predictions throughout the region use measurements from far less sensors than common techniques. Damage characteristics estimates using the proposed method showed damage attributes predictions with accuracy greater than 93 %. Simulation is used to validate the proposed method and the results are discussed. read more... read less...
Keywords: Vibration Analysis, Wind Turbine Damage, Kriging Analysis, Model Parameters, FEA, BEMM method