Review paper
Manufacturing Processes
Hasan Ghafourian Nosrati; Mahdi Gerdooei
Abstract
In recent years, most industries such as the aerospace, automotive, and others have been pushed to methods for reducing costs. One of these methods is the Rubber Pad Forming (RPF) process, which has been given more attention as a low-cost method than conventional methods. In RPF, unlike conventional ...
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In recent years, most industries such as the aerospace, automotive, and others have been pushed to methods for reducing costs. One of these methods is the Rubber Pad Forming (RPF) process, which has been given more attention as a low-cost method than conventional methods. In RPF, unlike conventional methods which mainly use metals as tools, one of the tools will be made of elastic pads. The RPF process has attracted the attention of many researchers around the world. Researchers from Iran started their work in this field around 2001 and subsequently published several remarkable articles. The first published Iranian study of the RPF process dates back to 2003, indicating that the use of flexible tools has a history of two decades in Iran. However, in the last decade, the number of published Iranian articles in the RPF process field and the introduction of new methods based on RPF and its simulation has increased. This review article aims to outline Iran's involvement in the RPF process, and it emphasizes that Iranian researchers predominantly contribute to the RPF process through simulation, experimental endeavors, and the introduction of innovative methods utilizing flexible tools.
Review paper
Robotics
Phongsavanh Sengaphone; Juan Miguel De Leon; Ronnie Concepcion; Argel A Bandala; Gerardo L Augusto; Raouf Naguib; Jeremias A Gonzaga; Joseph Aldrin Chua; Laurence A Gan Lim
Abstract
Integrating robotic technologies into agricultural practices has witnessed significant strides, particularly in tomato harvesting. This review paper offers a comprehensive examination of robot arms' end effectors developed for the intricate task of harvesting tomatoes. Drawing insights from a diverse ...
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Integrating robotic technologies into agricultural practices has witnessed significant strides, particularly in tomato harvesting. This review paper offers a comprehensive examination of robot arms' end effectors developed for the intricate task of harvesting tomatoes. Drawing insights from a diverse range of sources spanning Google Scholar, Scopus, IEEE Xplorer, and AnimoSearch, the study analyzes the trends, challenges, and future trajectories of employing robotic end effectors in the agricultural context. The investigation encompasses an in-depth exploration of various end-effector methodologies, including grippers, rotational mechanisms, scissor-type tools, and suction devices, elucidating their merits and prevalence in the current research literature. Focusing on the utilizations of end effectors in agricultural robotic harvesting systems, the review delves into fruit detachment methods, types of end tools designed explicitly for harvesting tomatoes, and the integration of sensors into end effectors for enhanced capabilities. The paper highlights the nuanced criteria involved in end effector design, emphasizing operational characteristics, technical features, and the need for adaptability to diverse fruit shapes. Furthermore, a detailed analysis of the challenges faced by end effectors in tomato harvesting is presented, with proposed solutions and recommendations for future research. The discussion extends to the future trends in this evolving field, envisioning advancements in sensing technology, artificial intelligence integration, adaptability, autonomy, and sustainability. In conclusion, the synthesis of technological innovation and agricultural expertise holds promise for reshaping tomato harvesting, paving the way for more sustainable, efficient, and cost-effective farming practices.
Research Paper
Rasool Esmaelnajad; Navid Farrokhi
Abstract
Increasing the power and improving the performance of diesel engines is always considered by diesel engine manufacturers. Changing the geometry of the injector outlet orifice has major impact on fuel-air mixing and combustion. In the current study, geometry of the injector orifice is changed from circular ...
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Increasing the power and improving the performance of diesel engines is always considered by diesel engine manufacturers. Changing the geometry of the injector outlet orifice has major impact on fuel-air mixing and combustion. In the current study, geometry of the injector orifice is changed from circular to annular cross-section, and the effect of different injection pressures on diesel engine performance is investigated. All numerical simulations are performed by using AVL Fire code. The results show that the annular injector improves combustion and engine performance by forming better fuel distribution. Fuel injection pressure affects the performance of the annular injector in terms of droplets distribution and breakup. At low injection pressures, due to the long injection duration, most of the fuel energy release occurs after top dead center (TDC). Therefore, the engine performance is improved, and the combustion chamber temperature and pressure are limited. However, at high injection pressures, less combustion occurs after TDC. By changing the injector geometry to the injector with annular cross-section orifice, the maximum reduction in SFC value is for case P5 and injection durations 10 degrees, which is decreased by 21.4%. In the studied cases, the maximum power increase was 15% for a 2.5% increase of fuel at injection pressure of 100MPa. While NO pollutant increased slightly by changing the type of injector at different injection pressures, the soot produced at the beginning of the combustion process is well oxidized before the end of the work phase, and its amount reached less than 2e-6.
Research Paper
Vibration
Al-Tekreeti Watban Khalid Fahmi; Kazem Reza Kashyzadeh; Siamak Ghorbani
Abstract
This research investigates the effectiveness of various vibration data acquisition techniques coupled with different machine learning models for detecting anomalies and classifying them. To this end, synthetic vibration data was generated for techniques such as Eddy Current Proximity Transducers (ECPT), ...
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This research investigates the effectiveness of various vibration data acquisition techniques coupled with different machine learning models for detecting anomalies and classifying them. To this end, synthetic vibration data was generated for techniques such as Eddy Current Proximity Transducers (ECPT), Accelerometer Sensor (AS), Blade Tip Timing (BTT), Laser Doppler Vibrometer (LDV), and Strain Gauge (SG). Afterward, the data was pre-processed and used to train Gradient Boosting Machine (GBM), Support Vector Machine (SVM), and Random Forest Models (RFMs). Performance evaluation metrics, including accuracy, recall, F1-score, and Receiver Operating Characteristic (ROC), and Area Under Curve (AUC) were employed to assess the models, revealing varying degrees of success across combining techniques and models. Notable achievements observed for the random forest model coupled with the eddy current proximity transducers technique, underscoring the significance of informed technical selection and model optimization in enhancing vibration anomaly detection systems in combined cycle power plants. The results showed that the LDV technique has a significant increase in accuracy from about 0.49 to approximately 0.52, while the ECPT technique has improved from about 0.9 to close 1.0. These advances highlight the growing accuracy of the methods and enable the development of more efficient and reliable learning machines.
Research Paper
Computational Fluid Dynamics (CFD)
Saeed Akbarnejad; Masoud Ziabasharhagh
Abstract
This paper presents a novel 1D modeling approach to optimize steam ejector entrainment ratios, introducing new definitions of ejector efficiency and methods for enhancement. Using the proposed model, an ejector is tailored for specific boundary conditions with available CFD results for validation. Dimensional ...
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This paper presents a novel 1D modeling approach to optimize steam ejector entrainment ratios, introducing new definitions of ejector efficiency and methods for enhancement. Using the proposed model, an ejector is tailored for specific boundary conditions with available CFD results for validation. Dimensional and geometrical parameters are computed from the theoretical 1D model, and various geometries are explored using CFD to determine entrainment ratios.Innovative definitions of ejector efficiency are introduced. The first definition compares the entrainment ratio of the ejector to a system comprising a steam compressor, turbine, and mixer, yielding an efficiency of 13.5% under specified conditions. The second, more practical definition calculates the maximum achievable entrainment ratio, disregarding frictional losses, resulting in an efficiency of 70%.An algorithm is proposed to optimize ejector dimensions to approach this maximum. Using this algorithm, the optimum throat diameter was determined through CFD analysis, demonstrating an increase in the entrainment ratio from 0.7 to 1.25. The theoretical maximum value calculated by the 1D model is 1.282, indicating 97.7% of the theoretical maximum was achieved in CFD simulations. This highlights the significant improvement in the entrainment ratio using the 1D model and delineates its limit under given conditions.The third definition establishes the theoretical maximum entrainment ratio given specific boundary conditions and dimensions, assuming no losses in the nozzle, mixing process, or diffuser, yielding an efficiency of 81% for the same ejector studied.
Research Paper
Biomechanics
Adel Maghsoudpour; Ali Dorostghol; Ali Ghaffari; Mansour NikkhahBahrami
Abstract
To quickly detect sudden Cardiac Death (SCD), it's decisive to gather suitable information and enhance the accuracy of the diagnosis algorithms. Consequently, In the present study the heart rate variability (HRV) signal of subjects who experienced sudden cardiac death (SCD) was studied. We looked at ...
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To quickly detect sudden Cardiac Death (SCD), it's decisive to gather suitable information and enhance the accuracy of the diagnosis algorithms. Consequently, In the present study the heart rate variability (HRV) signal of subjects who experienced sudden cardiac death (SCD) was studied. We looked at people's heart signals for one hour before something happened to see if there were any noticeable changes. The patients' HRV signals are segregated into 5-minute parts in the suggested approach. Each section is divided into four shorter signals. Thereupon, The energy and instant amplitude of each sub-signal are examined. The information flows between signal strengths and measuring the complexity of energy sub-signals would be checked. A significant change from its former section is identified. A support vector machine (SVM) classifier benefits from detecting individuals exposed to SCD by considering significant changes as indicators of the SCD process. It can anticipate SCD 15 minutes before it happens. Not restricted to any special subclass of cardiac diseases, this technique has priority. To evaluate the algorithm's specificity, it has been used not only with patients having SCD but also with individuals who are healthy, as well as those with coronary artery disease (CAD) and congestive heart failure (CHF), analyzing their HRV signals. The specificity values for normal, CHF, and CAD patients are 100%, 93.3%, and 95.6%, respectively, in the results.
Research Paper
Computational Fluid Dynamics (CFD)
Nader Pourmahmoud; Aydin Zabihi
Abstract
Cooling tubes are inserted into the desiccant dehumidifier liquid of a 3-fluid liquid-to-air membrane energy exchanger (LAMEE) in order to regulate the temperature of the dehumidifier liquid. As a result, the 3-fluid LAMEE's performance is significantly influenced by the refrigerated tubes. The numerical ...
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Cooling tubes are inserted into the desiccant dehumidifier liquid of a 3-fluid liquid-to-air membrane energy exchanger (LAMEE) in order to regulate the temperature of the dehumidifier liquid. As a result, the 3-fluid LAMEE's performance is significantly influenced by the refrigerated tubes. The numerical analysis of the present work shows that the number of chilled tubes and their inner diameter affect the effectiveness (total, latent, and sensible) rate of moisture removal and adequate cooling power, and exergy loss. Additionally, the dehumidifier liquid channel receives the addition of wavy cooling tubes for the first time. The relationship between wave height and wave length is known as wave steepness, and its impact on efficiency and energy loss is also examined. Numerical studies show that the number and inner diameter of the cooling tubes have a direct correlation with the efficiency of the 3-fluid LAMEE. The improved the efficiency, the more cooled tubes there are and the larger their diameter. Furthermore, both exergy loss and without dimensions exergy loss increase with the quantity and diameter of refrigerated tubes. The sensible and latent effectiveness of the 3-fluid LAMEE is increased by the wavy refrigeration tubes as compared to straight tubes; the augmentation of the sensible and latent effectiveness increases with wave steepness.
Research Paper
Energy Science and Technology
Shaaban Ghodbanan; Reza Alizadeh; Sirous Shafiei; Javad Rahbar Shahrouzi
Abstract
In this study the energy assessment and heat recovery analysis of multi-cylinder drying section were carried out in a fluting paper machine. The specific heat consumption per unit of paper was determined to be about 4.7 GJ per ton of paper and accordingly, the machine consumed about 1.71 tons steam per ...
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In this study the energy assessment and heat recovery analysis of multi-cylinder drying section were carried out in a fluting paper machine. The specific heat consumption per unit of paper was determined to be about 4.7 GJ per ton of paper and accordingly, the machine consumed about 1.71 tons steam per ton of produced paper. The temperature efficiency of the heat exchanger and recovering efficiency of the heat recovery system of the paper machine have been determined to be about 50% and 4%, respectively. The results show that the steam use in the heat recovery system can be reduced by about 0.95 ton/h due to adjusting the supply air temperature to the optimum range, which corresponds to about 5.2% reduction in energy input and 4% improvement in dryer efficiency resulting nearly 31,000 $ savings per year. Also, the CO2 emission due to gas use can be decreased about 925 tons per year.
