Adel M. Al-Shayea, Emad S. Abouel Nasr, H. Al-Mubaid, A. Al-Ahmari, A. Kamrani, Husam Kaid, Haitham A. Mahmoud
{"title":"A New Association Analysis-Based Method for Enhancing Maintenance and Repair in Manufacturing","authors":"Adel M. Al-Shayea, Emad S. Abouel Nasr, H. Al-Mubaid, A. Al-Ahmari, A. Kamrani, Husam Kaid, Haitham A. Mahmoud","doi":"10.21278/tof.454025420","DOIUrl":"https://doi.org/10.21278/tof.454025420","url":null,"abstract":"","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Aleksić, S. Bulatović, Bojana Zečević, A. Maksimović, L. Milović
{"title":"Processing of Data Obtained by the Testing of Steel under Low Cyclic Fatigue (Part I)","authors":"V. Aleksić, S. Bulatović, Bojana Zečević, A. Maksimović, L. Milović","doi":"10.21278/tof.464041622","DOIUrl":"https://doi.org/10.21278/tof.464041622","url":null,"abstract":"","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67957345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Todić, Milan T. Djordjević, D. Arsić, D. Džunić, V. Lazić, S. Aleksandrović, B. Krstić
{"title":"Influence of Vanadium Content on the Tribological Behaviour of X140CrMo12-1 Air-Hardening Steel","authors":"A. Todić, Milan T. Djordjević, D. Arsić, D. Džunić, V. Lazić, S. Aleksandrović, B. Krstić","doi":"10.21278/tof.462035021","DOIUrl":"https://doi.org/10.21278/tof.462035021","url":null,"abstract":"","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67957514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Švagždytė, S. Borodinas, A. Kilikevičius, V. Mokšin
The paper presents a new type of flat surface polishing device. The polishing disc rotates using the pressure of compressed air. The polishing disc has a special geometry, wherein it has holes for flow turbulence minimisation in the air pressure areas of the boundary. The influence of the hole inclination angle on the rotational speed of the disk and the system efficiency was studied experimentally and numerically. It was established that the optimal inclination angle is a 20° angle that results in the maximum efficiency of the proposed system. In the experiment, three polishing discs with hole inclination angles of 0°, 20°, and 30° were studied; the discs were rotated using four air pressure values: 0.2, 0.3, 0.4, and 0.5 MPa. It was found that the optimal inclination angle of holes was 20° and that the fastest rotational speed, i.e. 1900 1/min, was reached at a maximum air pressure of 0.5 MPa.
{"title":"Investigation Into Levitating Polishing Disc Used for Flat Surface Finishing","authors":"I. Švagždytė, S. Borodinas, A. Kilikevičius, V. Mokšin","doi":"10.21278/tof.452010119","DOIUrl":"https://doi.org/10.21278/tof.452010119","url":null,"abstract":"The paper presents a new type of flat surface polishing device. The polishing disc rotates using the pressure of compressed air. The polishing disc has a special geometry, wherein it has holes for flow turbulence minimisation in the air pressure areas of the boundary. The influence of the hole inclination angle on the rotational speed of the disk and the system efficiency was studied experimentally and numerically. It was established that the optimal inclination angle is a 20° angle that results in the maximum efficiency of the proposed system. In the experiment, three polishing discs with hole inclination angles of 0°, 20°, and 30° were studied; the discs were rotated using four air pressure values: 0.2, 0.3, 0.4, and 0.5 MPa. It was found that the optimal inclination angle of holes was 20° and that the fastest rotational speed, i.e. 1900 1/min, was reached at a maximum air pressure of 0.5 MPa.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41630487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Vicen, J. Bronček, O. Bokůvka, R. Nikolić, N. Radek
COATING Summary Tribological behaviour of the Sucaslide diamond-like carbon coating applied to low-alloy steel was studied in this research. Experimental work included the determination of the chemical composition and the evaluation of the microstructure of both the base material and the Sucaslide coating. The methods used in the research were dilatometry and energy dispersive x-ray analysis, mechanical properties measurements, and wear resistance and scratch tests. From the results obtained in experiments, the authors concluded that the Sucaslide DLC coating has very good sliding and abrasion-resistant properties. With regard to these facts, it is possible to recommend the Sucaslide DLC coating for application to the low-alloy steel used in the bearing
{"title":"Tribological Behaviour of the Sucaslide Diamond-like Carbon Coating","authors":"M. Vicen, J. Bronček, O. Bokůvka, R. Nikolić, N. Radek","doi":"10.21278/tof.452019320","DOIUrl":"https://doi.org/10.21278/tof.452019320","url":null,"abstract":"COATING Summary Tribological behaviour of the Sucaslide diamond-like carbon coating applied to low-alloy steel was studied in this research. Experimental work included the determination of the chemical composition and the evaluation of the microstructure of both the base material and the Sucaslide coating. The methods used in the research were dilatometry and energy dispersive x-ray analysis, mechanical properties measurements, and wear resistance and scratch tests. From the results obtained in experiments, the authors concluded that the Sucaslide DLC coating has very good sliding and abrasion-resistant properties. With regard to these facts, it is possible to recommend the Sucaslide DLC coating for application to the low-alloy steel used in the bearing","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49101932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A floating type liquefied natural gas (LNG) bunkering terminal has been under development in Korea since 2014; the terminal is designed to receive LNG from an LNG carrier (LNGC) and transfer it to two other LNG bunkering shuttles (LNGBS) simultaneously. The operational feasibility of the LNG loading and unloading processes has been confirmed. When four vessels are moored side by side with mooring ropes and fenders, their positions must be maintained within the designed allowable criteria. In addition, the floating bunkering terminal (FLBT) has its own mooring system, an internal turret with catenary mooring lines and stern tunnel thrusters to maintain its own position and control the vessel heading. In this study, we investigated the operational feasibility of the FLBT during the LNG loading and unloading operations with four vessel mooring configurations and heading controls. A series of model tests was done in the ocean engineering basin of the Korea Research Institute of Ships and Ocean engineering. The motion responses of the four vessels were determined using an optical measurement system, and the tensile loads on shipto-ship mooring ropes and the compressive loads on ship-to-ship fenders were measured using one-axis load cells. A white noise test was done and the results were compared with the numerical results for the purpose of validation. Then, four combined environmental conditions were presented both without heading control and with several heading control cases. Finally, we determined the available safe bunkering heading ranges taking into account the tensile loads on the mooring ropes.
{"title":"Experimental Study on Coordinated Heading Control of Four Vessels Moored Side by Side","authors":"Yun-Ho Kim, D. Jung, H. Song, Y. Won, D. Jung","doi":"10.21278/TOF.451013720","DOIUrl":"https://doi.org/10.21278/TOF.451013720","url":null,"abstract":"A floating type liquefied natural gas (LNG) bunkering terminal has been under development in Korea since 2014; the terminal is designed to receive LNG from an LNG carrier (LNGC) and transfer it to two other LNG bunkering shuttles (LNGBS) simultaneously. The operational feasibility of the LNG loading and unloading processes has been confirmed. When four vessels are moored side by side with mooring ropes and fenders, their positions must be maintained within the designed allowable criteria. In addition, the floating bunkering terminal (FLBT) has its own mooring system, an internal turret with catenary mooring lines and stern tunnel thrusters to maintain its own position and control the vessel heading. In this study, we investigated the operational feasibility of the FLBT during the LNG loading and unloading operations with four vessel mooring configurations and heading controls. A series of model tests was done in the ocean engineering basin of the Korea Research Institute of Ships and Ocean engineering. The motion responses of the four vessels were determined using an optical measurement system, and the tensile loads on shipto-ship mooring ropes and the compressive loads on ship-to-ship fenders were measured using one-axis load cells. A white noise test was done and the results were compared with the numerical results for the purpose of validation. Then, four combined environmental conditions were presented both without heading control and with several heading control cases. Finally, we determined the available safe bunkering heading ranges taking into account the tensile loads on the mooring ropes.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48157181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Ćurković, Rea Veseli, Ivan Gabelica, I. Žmak, Ivana Ropuš, M. Vukšić
The present study examines the potential of microwave heating as an emerging and innovative energy-efficient alternative to conventional heating techniques used for different materials, with a focus on the processing of ceramic materials. Modern ceramics are studied extensively, and their use and different applications are wide due to many advantages of these materials. The most important factor in microwave sintering which differentiates it from conventional heating techniques is a unique heat transfer mechanism. Microwave energy is absorbed by the material, hence the transfer of energy takes place at the molecular level. This way, the heat is generated throughout the material, i.e. on the inside as well on the outside. This allows a very low temperature gradient throughout the material cross section. When conventional sintering is used, typically at high heating rates, high temperature gradients pose a problem. The accelerated microwave heating occurs through the whole volume, so the heating is uniform, which limits the grain growth and coarsening, and leads to a uniform and fine microstructure. The densification is accelerated as well during the unique heat transfer mechanism of microwave sintering, which enhances the mechanical properties of the sintered materials. This paper discusses the use of microwave sintering in the manufacturing of different modern technical materials, namely ceramics, composites, metals and alloys, and glasses. The improvement of different properties is described using the available literature.
{"title":"A Review of Microwave-Assisted Sintering Technique","authors":"L. Ćurković, Rea Veseli, Ivan Gabelica, I. Žmak, Ivana Ropuš, M. Vukšić","doi":"10.21278/TOF.451021220","DOIUrl":"https://doi.org/10.21278/TOF.451021220","url":null,"abstract":"The present study examines the potential of microwave heating as an emerging and innovative energy-efficient alternative to conventional heating techniques used for different materials, with a focus on the processing of ceramic materials. Modern ceramics are studied extensively, and their use and different applications are wide due to many advantages of these materials. The most important factor in microwave sintering which differentiates it from conventional heating techniques is a unique heat transfer mechanism. Microwave energy is absorbed by the material, hence the transfer of energy takes place at the molecular level. This way, the heat is generated throughout the material, i.e. on the inside as well on the outside. This allows a very low temperature gradient throughout the material cross section. When conventional sintering is used, typically at high heating rates, high temperature gradients pose a problem. The accelerated microwave heating occurs through the whole volume, so the heating is uniform, which limits the grain growth and coarsening, and leads to a uniform and fine microstructure. The densification is accelerated as well during the unique heat transfer mechanism of microwave sintering, which enhances the mechanical properties of the sintered materials. This paper discusses the use of microwave sintering in the manufacturing of different modern technical materials, namely ceramics, composites, metals and alloys, and glasses. The improvement of different properties is described using the available literature.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"66 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41330267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In manufacturing system management, the decisions are currently made on the base of ‘what if’ analysis. Here, the suitability of the model structure based on which a model of the activity will be built is crucial and it refers to multiple conditionality imposed in practice. Starting from this, finding the most suitable model structure is critical and represents a notable challenge. The paper deals with the building of suitable structures for a manufacturing system model by data-driven causal modelling. For this purpose, the manufacturing system is described by nominal jobs that it could involve and is identified by an original algorithm for processing the dataset of previous instances. The proposed causal modelling is applied in two case studies, whereby the first case study uses a dataset of artificial instances and the second case study uses a dataset of industrial instances. The causal modelling results prove its good potential for implementation in the industrial environment, with a very wide range of possible applications, while the obtained performance has been found to be good.
{"title":"Data-Driven Causal Modeling of the Manufacturing System","authors":"G. Frumuşanu, C. Afteni, A. Epureanu","doi":"10.21278/TOF.451020920","DOIUrl":"https://doi.org/10.21278/TOF.451020920","url":null,"abstract":"In manufacturing system management, the decisions are currently made on the base of ‘what if’ analysis. Here, the suitability of the model structure based on which a model of the activity will be built is crucial and it refers to multiple conditionality imposed in practice. Starting from this, finding the most suitable model structure is critical and represents a notable challenge. The paper deals with the building of suitable structures for a manufacturing system model by data-driven causal modelling. For this purpose, the manufacturing system is described by nominal jobs that it could involve and is identified by an original algorithm for processing the dataset of previous instances. The proposed causal modelling is applied in two case studies, whereby the first case study uses a dataset of artificial instances and the second case study uses a dataset of industrial instances. The causal modelling results prove its good potential for implementation in the industrial environment, with a very wide range of possible applications, while the obtained performance has been found to be good.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"70 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei-xuan Jiao, Li Cheng, Di Zhang, Bowen Zhang, Yeping Su
The hydraulic performance of an inlet duct directly affects the overall performance of a waterjet propulsion system. Key parameters for the hydraulic optimization of the inlet duct are explored using the computational fluid dynamics (CFD) technology to improve the hydraulic performance of the waterjet propulsion system. In the CFD simulation and experiment, an inlet duct with different flow and geometric parameters is simulated. By comparing grid sensitivity and different turbulence models, a suitable grid size and a turbulence model are determined. The comparison between the numerical simulation and the experiment shows that the numerical results are reliable. The results of the calculation and analysis of different speed cases show that the ship speed affects the efficiency of the waterjet propulsion system. In particular, the system efficiency increases first and then decreases with an increase in the ship speed. Under the conditions of constant ship speed and rotational speed, the influence of the length and dip angle of the inlet duct on the waterjet propulsion system is investigated using a single factor method. The results show that the dip angle has an obvious effect on the hydraulic performance of the inlet duct, and an extremely small angle of inclination will lead to poor flow patterns in the inlet passage. When the length is approximately six times the inlet duct outlet diameter, and the dip angle is 30°–35°, the hydraulic performance of the waterjet propulsion pump system is satisfactory.
{"title":"Investigation of Key Parameters for Hydraulic Optimization of an Inlet Duct Based on a Whole Waterjet Propulsion Pump System","authors":"Wei-xuan Jiao, Li Cheng, Di Zhang, Bowen Zhang, Yeping Su","doi":"10.21278/TOF.451004819","DOIUrl":"https://doi.org/10.21278/TOF.451004819","url":null,"abstract":"The hydraulic performance of an inlet duct directly affects the overall performance of a waterjet propulsion system. Key parameters for the hydraulic optimization of the inlet duct are explored using the computational fluid dynamics (CFD) technology to improve the hydraulic performance of the waterjet propulsion system. In the CFD simulation and experiment, an inlet duct with different flow and geometric parameters is simulated. By comparing grid sensitivity and different turbulence models, a suitable grid size and a turbulence model are determined. The comparison between the numerical simulation and the experiment shows that the numerical results are reliable. The results of the calculation and analysis of different speed cases show that the ship speed affects the efficiency of the waterjet propulsion system. In particular, the system efficiency increases first and then decreases with an increase in the ship speed. Under the conditions of constant ship speed and rotational speed, the influence of the length and dip angle of the inlet duct on the waterjet propulsion system is investigated using a single factor method. The results show that the dip angle has an obvious effect on the hydraulic performance of the inlet duct, and an extremely small angle of inclination will lead to poor flow patterns in the inlet passage. When the length is approximately six times the inlet duct outlet diameter, and the dip angle is 30°–35°, the hydraulic performance of the waterjet propulsion pump system is satisfactory.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47568484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The exergy analysis of an air conditioning process in wintertime is presented in this paper. This process consists of mixing outdoor air with conditioned air, heating, humidifying, and reheating the air mixture. The air is heated in the heat exchangers by warm water at a temperature of 80/60C and humidified by spraying water at a temperature of 12 C. The ratio of the mass flow rates of outdoor and conditioned air is varied, and it is upon this variable that the exergy analysis is performed. The five cases are analyzed with different outdoor air temperature values. It is shown that the heat transfer rate in the heat exchangers is the smallest at the ratio of mass flow rates of outdoor and conditioned air g1 = 0.45. The greatest exergy destruction is apparent in the heat exchangers, and the maximum exergy efficiency of the whole process ex = 0.71 is achieved at the ratio g1 = 0.45. According to the exergy criterion, this air conditioning is a relatively efficient process.
{"title":"Exergy Analysis of an Air Conditioning Process","authors":"Matej Đuranović, M. Rauch, A. Galovic, M. Živić","doi":"10.21278/TOF.SI1005721","DOIUrl":"https://doi.org/10.21278/TOF.SI1005721","url":null,"abstract":"The exergy analysis of an air conditioning process in wintertime is presented in this paper. This process consists of mixing outdoor air with conditioned air, heating, humidifying, and reheating the air mixture. The air is heated in the heat exchangers by warm water at a temperature of 80/60C and humidified by spraying water at a temperature of 12 C. The ratio of the mass flow rates of outdoor and conditioned air is varied, and it is upon this variable that the exergy analysis is performed. The five cases are analyzed with different outdoor air temperature values. It is shown that the heat transfer rate in the heat exchangers is the smallest at the ratio of mass flow rates of outdoor and conditioned air g1 = 0.45. The greatest exergy destruction is apparent in the heat exchangers, and the maximum exergy efficiency of the whole process ex = 0.71 is achieved at the ratio g1 = 0.45. According to the exergy criterion, this air conditioning is a relatively efficient process.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49302744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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