Tehnicki vjesnik - Technical Gazette最新文献

{"title":"The Modern Single Shaft Gas Turbine Rotor Stress-Strain State Determination Taking into Account the Contact Thermoelasticity Problem","authors":"Natalia Smetankina, S. Morhun","doi":"10.17559/tv-20230628000770","DOIUrl":"https://doi.org/10.17559/tv-20230628000770","url":null,"abstract":"The paper outlines a finite elements refined mathematical model of the stress-strain state of single shaft gas turbine engine that can be used in ground or floating power plants. The mathematical model is taken into consideration the contact thermoelasticity problem in the joint area of disk and blades. On the base of the developed mathematical model the fields of turbine rotor dynamic stresses and displacement have been found too. To make the clear decision about the developed mathematical model adequacy mostly loaded impeller dynamic stresses field has been found and verified by comparison with the calculated results without contact and experimental data. The turbine rotor displacements and dynamic stresses have been found for different forced vibration modes. The obtained results along with the previous studies of this rotor fluid flow and thermal state could be used in further studies of the turbine rotor creep and fatigue strength and blades crack researches.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"299 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140703755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron Intermetallic Compounds (IMCs) Formation Mechanism in the Molten Aluminium Zinc (Al-Zn) Coating Alloy","authors":"Abdul Khaliq, Vishnu Kasva, A. S. Alghamdi, Mohamed Ramadan, T. Subhani, Waseem Haider, K. S. A. Halim","doi":"10.17559/tv-20230523000660","DOIUrl":"https://doi.org/10.17559/tv-20230523000660","url":null,"abstract":": To prevent corrosion of steel products, the steel industry often relies on Al-Zn based alloy coatings, applied through hot-dip coating technology. Despite this, a long-standing problem in the galvanizing industry involves the formation of Fe-based intermetallic compounds (IMCs) in the Al-Zn coating bath, caused by iron dissolution from steel products. Such IMCs are the primary source of dross formation in the Al-Zn bath, which inevitably leads to metal spot defects in the coated steel products and bottom dross build-up in the Al-Zn bath. The present research aims to investigate the mechanism of Fe transformation into IMCs. To achieve this, Fe saturated and unsaturated Al-Zn alloys were doped with low carbon steel at a temperature of 600 °C. The samples were collected at regular intervals and quenched in water. The optical microscopy (OM) and scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) were used to study the transformation of steel strips into Fe-IMCs particles in molten Al-Zn alloys. The study findings suggest that the Fe transformation into Fe-IMCs is a complex process, where the steel strip surface is initially oxidized, and Al 5 Fe 2 and Al 3 Fe are formed, which finally transform into Al 8 Fe 2 Si(Zn) ( τ 5c) IMCs particles. These results can assist galvanizers in understanding formation of Fe-IMCs and bottom dross build up in the costing pots.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"9 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140702049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On Site Measurement and Evaluation of Environmental Vibration Caused by Ordinary Speed Train Operation","authors":"Xin Zheng, Shunfeng Chen, Hengyan Xie","doi":"10.17559/tv-20231024001054","DOIUrl":"https://doi.org/10.17559/tv-20231024001054","url":null,"abstract":": In order to study the environmental vibration characteristics and evaluation of the saturated soil site in the cold northern region caused by the train, vibration observation was carried out on a saturated soil site in a near railway area of the Harbin-Manzhouli Railway, and the environmental vibration caused by different trains at different operating speeds was analyzed in the time and frequency domains. The observation results were evaluated by using the 1/3 octave vibration acceleration level and the maximum weighted plumb vibration level as evaluation index. The results show that the acceleration decreases with the increase of distance, and the acceleration decreases rapidly from 10 m to 30 m, and slowly after 30 m. The vibration energy of the measurement points at 10 m and 20 m is concentrated in 15 - 60 Hz, and the vibration energy of the measurement points after 30 m is concentrated in 15 - 20 Hz. With the increase of the distance from the center of the track, the 1/3 octave vibration acceleration level and the maximum weighted plumb vibration level all show a trend of attenuation. The maximum weighted plumb vibration levels at 30 m are 70.8 dB and 71.3 dB for upward and downward trains, and 77.4 dB and 71.4 dB for upward and downward freight trains, respectively, which are greater than the weighted plumb vibration level limit for special residential buildings. The maximum value of vibration acceleration level at the 10 m measurement point is 88.6 dB, which exceeds the limit by 9.5 dB, and that of 30 m measurement point is 69.8 dB, which meets the specification requirements. The results of the study can provide basic data for the environmental vibration characterization of saturated soil sites caused by train operation and the environmental vibration design of residential, agricultural and water conservancy infrastructures in the near-railway area.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"4 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140702393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and Numerical Analyses of the Temperature Field in the Ironing Process","authors":"V. Mandic, D. Adamović, Zoran Jurković, Marko Delić","doi":"10.17559/tv-20231115001106","DOIUrl":"https://doi.org/10.17559/tv-20231115001106","url":null,"abstract":": The purpose of this paper is to determine the temperature fields in the workpiece and the tool in the ironing process using an integrated approach that includes laboratory experiments and numerical modelling. An originally developed model device for ironing sheet metal strips, which was previously shaped by U - bending, was used for the experimental research. Thermocouples were installed in the device at the position close to the contact surface with the workpiece. The device was mounted on a hydraulic press that enables maximum ironing speeds of v=4.17 mm/s. In order to determine the temperature fields at higher ironing speeds, a series of numerical experiments was performed at identical speeds as in the experiments (0.33 mm/s and 4.17 mm/s) and at higher speeds (100 mm/s, 1000 mm/s and 10000 mm/s). Good matches of the experimental and numerical results at lower speeds were obtained, so the numerical estimates at higher speeds were valid for the analysis and conclusions. With the increase of the ironing speed , a trend of temperature increase is evident. The maximum temperature of 166°C at ironing speed of 10000 mm/s that corresponds to manufacturing of 250 cans per minute is significantly lower than the critical melting temperature of the tin coating.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140699736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of Leachate Drainage System in Shallow Landfill Areas","authors":"Junsheng Wang, Zanli Jia, Biao Zhou, Liyong Zhang, MA Lan","doi":"10.17559/tv-20230607000703","DOIUrl":"https://doi.org/10.17559/tv-20230607000703","url":null,"abstract":": Leachate drainage systems in landfills often face issues like pipe blockage and reduced seepage flow over time. Inadequate leachate drainage can lead to rising leachate levels in the waste heap, negatively impacting landfill gas collection efficiency. This study aimed to develop and test an air-lift device to improve leachate drainage in shallow landfills. The air-lift device was designed to lift leachate while allowing simultaneous landfill gas collection under negative pressure. Experiments examined how air pressure, submergence depth, pipe diameters, and lifting height affected the leachate outlet flow rate of the device. Orthogonal experimental analysis found submergence depth and lifting height had the most significant influence on outlet flow rate. A multiple regression model was developed to quantify the effects of these parameters. Additionally, a foam separator was incorporated into the device design and removed 20 - 30% of non-settleable particles from the leachate. While the foam separator improved leachate water quality, its effect on air quality requires further study. Overall, the air-lift device successfully lifted leachate and collected landfill gas simultaneously, providing an efficient alternative drainage method for shallow landfills.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"32 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140699323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation Mechanism and Implementation Path of a Digital Agriculture Innovation Ecosystem","authors":"Yongxiang He, Jinghua Song, Wenjun Ouyang, Qinghua Li","doi":"10.17559/tv-20231107001080","DOIUrl":"https://doi.org/10.17559/tv-20231107001080","url":null,"abstract":": Digital agricultural innovation ecosystems defined the notion of agricultural innovation ecosystems in regional areas. Developing a data economy for agriculture based on digital spaces necessitates an awareness of and proficiency with digital innovation ecosystems. The digital formation of agriculture has played a great role in enhancing agrarian production, encouraging the ecological development of the agricultural economy, and accomplishing sustainable economic goals. The profound integration of the digital economy and the agriculture industry has become a major concern. A multifaceted technology expansion across the agricultural economy, a Remote Sensing Assisted Digital Agriculture Innovation Ecosystem (RS-DAIE) has been developed to enhance country-level digital agriculture requirements. Therefore, simple guidelines for building an efficient marketing strategy are crucial for expanding access to healthy food options and fostering the growth of organic farmers locally and internationally. The trial findings show that RS-DAIE has the finest accuracy by 98.9%, reliability rate by 99.3%, data transmission by 97.3%, and moisture content ratios, which are better than other technologies.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"50 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140702537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Architectural Color Conservation and Renewal Strategies in Historic Urban Areas: An Analysis Based on the Historic City of Macao","authors":"","doi":"10.17559/tv-20231127001153","DOIUrl":"https://doi.org/10.17559/tv-20231127001153","url":null,"abstract":"","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"29 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140703077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computer Vision-Based Risk Assessment on Heterogeneous Mobile Network Operating Environments","authors":"Youngjun Kim, Namkyun Baik","doi":"10.17559/tv-20230328000486","DOIUrl":"https://doi.org/10.17559/tv-20230328000486","url":null,"abstract":": In order to logically prioritize the urgent risks in the heterogeneous mobile network operating environment, we derive environmental factors that can reflect the characteristics of the heterogeneous network operating environment and present them as an improved security risk assessment formula. The prioritized risks derived through this improved risk assessment formula can visually express the severity of the risk by using computer vision. The purpose of this study was to derive environmental factors that can reflect the security control characteristics of various heterogeneous network operating environments and to apply them to security risk evaluation formulas to prioritize urgent risks and easily identify the degree of security risks. In the existing risk assessment formula, risk is calculated based on three indices: the importance of the asset, the vulnerability score, and the threat score. However, two problems were derived from the existing risk assessment. First, the existing risk assessment formula is insufficient to reflect the controlled environment characteristics of each network because the risk level is calculated based on individual assets. Second, if the same systems with the same purpose (same settings) are operated in different heterogeneous network operating environments, they are counted at the same risk level, and action cannot be prioritized quickly. To solve these problems, we propose an indicator called environmental factor ( E ), which is a combination of three indices. The three indices are \"Network Diversity Index ( NDI ), network Zone Separation Index ( ZSI ) and Control Level Index ( CLI )\". NDI expressed the diversity of networks numerically. ZSI is a numerical expression of the complexity of the network zone. CLI is a numerical expression of the degree of network control level. Results of the study showed that the risk assessment formula applying the proposed risk assessment factors can quickly identify urgent risks and act quickly. In heterogeneous mobile network operating environment in which numerous systems are operated, really urgent risks among the risks calculated through the proposed risk assessment will be handled quickly and logically.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"327 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140703705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Secure Storage of Big Data at Rest with Improved ECC and Paillier Homomorphic Encryption Algorithms","authors":"HU Rong, Ping Huang","doi":"10.17559/tv-20230618000745","DOIUrl":"https://doi.org/10.17559/tv-20230618000745","url":null,"abstract":": With the rapid growth of Big Data, securing its storage has become crucial. This study proposes to enhance the secure storage of big data at rest in Hadoop by improving encryption algorithms. The Elliptic Curve Cryptography Algorithm (ECC) is upgraded by a parallel two-threaded approach for unstructured data. For structured data, enhance Paillier Homomorphic Encryption to support operations on ciphertexts. Experiments on datasets up to 4 G show that the modified ECC method reduces encryption time to 60 - 80 seconds, compared to 100 - 160 seconds for standard ECC, AES, and DES. It can also use shorter key lengths than RSA with comparable levels of security. Enhanced Paillier encryption uses large prime numbers to ensure the validity of the ciphertext. By combining these improved encryption techniques within a secure Hadoop framework, this research demonstrates an effective way to address vulnerabilities in Big Data storage.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"290 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140703931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid Metallurgy Synthesis of Gr or MoS2-Reinforced Aluminum Composites: A Short Review","authors":"","doi":"10.17559/tv-20221013131240","DOIUrl":"https://doi.org/10.17559/tv-20221013131240","url":null,"abstract":": This review briefs the vortex casting and hardness of mono aluminium matrix composites (AMCs) and hybrid AMCs (HAMCs) containing lamellar solids (Gr (graphite) or MoS 2 particles). The vortex addition process and the associated process parameters to fabricate the mono and hybrid AMCs are discussed. The Gr particles are coated with Ni or Cu where they alloyed with the melt to enhance the wettability. Furthermore, the addition of alloying elements and the particle preheating improve the wetting of the uncoated lamellar solids with the melt. The Gr-reinforced or MoS 2 reinforced mono AMCs exhibited a decrease in hardness with the addition of lamellar solids. In HAMCs, the ceramic particles resist the indentation, leading to their better hardness than the lamellar solid reinforced mono AMCs.","PeriodicalId":510054,"journal":{"name":"Tehnicki vjesnik - Technical Gazette","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140699500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}