Ricardo Júnior de Oliveira Silva, Natália Pereira de Azevedo, F. Drozda
- This article presents a study carried out with 24 parts printed using 3D FDM printer. The main objective of the research was to contribute to the optimization of printed parts in additive manufacturing by fused deposition modeling (FDM). To make this possible, the DoE methodology was used together with the Taguchi’s method. This study confirmed that the three-dimensional printing FDM parameters influence the dimensional accuracy of the parts. When using FDM additive manufacturing, it is recommended to analyze the position in which the part will be printed, to guarantee it dimensional accuracy. Also, it is important to check the layer height and print speed of the fill, which reflects on the print time, to ensure the part has high dimensional accuracy.
{"title":"Dimensional Precision of Abs Parts Manufactured By Additive Manufacturing in FDM Technology","authors":"Ricardo Júnior de Oliveira Silva, Natália Pereira de Azevedo, F. Drozda","doi":"10.11159/icmie22.101","DOIUrl":"https://doi.org/10.11159/icmie22.101","url":null,"abstract":"- This article presents a study carried out with 24 parts printed using 3D FDM printer. The main objective of the research was to contribute to the optimization of printed parts in additive manufacturing by fused deposition modeling (FDM). To make this possible, the DoE methodology was used together with the Taguchi’s method. This study confirmed that the three-dimensional printing FDM parameters influence the dimensional accuracy of the parts. When using FDM additive manufacturing, it is recommended to analyze the position in which the part will be printed, to guarantee it dimensional accuracy. Also, it is important to check the layer height and print speed of the fill, which reflects on the print time, to ensure the part has high dimensional accuracy.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130570396","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}
Deniz Perin, Alper Akça, K. Yilmaz, A. D. Karaoglan
- The design of a 10 kW high-speed generator is optimized in this research. The objective is to optimize the design parameters of the high speed generator namely pole body width, pole shoe height, pole shoe width for the responses (pole shoe flux density, pole body flux density, rotor yoke flux density, efficiency, shaft torque, exciting current, exciting current density). Response surface face centered design is used for experimental design and mathematical modelling. Then salp swarm algorithm – which is a recently invented meta-heuristic algorithm – is used for performing the optimization. The experimental data is obtained from ANSYS MAXWELL simulations. The confirmations are also performed by ANSYS MAXWELL. The results show that the SSA is a good optimizer for these types of electric machines.
{"title":"Design Optimization of 10 kW High Speed Generator by using Salp Swarm Algorithm","authors":"Deniz Perin, Alper Akça, K. Yilmaz, A. D. Karaoglan","doi":"10.11159/icmie22.102","DOIUrl":"https://doi.org/10.11159/icmie22.102","url":null,"abstract":"- The design of a 10 kW high-speed generator is optimized in this research. The objective is to optimize the design parameters of the high speed generator namely pole body width, pole shoe height, pole shoe width for the responses (pole shoe flux density, pole body flux density, rotor yoke flux density, efficiency, shaft torque, exciting current, exciting current density). Response surface face centered design is used for experimental design and mathematical modelling. Then salp swarm algorithm – which is a recently invented meta-heuristic algorithm – is used for performing the optimization. The experimental data is obtained from ANSYS MAXWELL simulations. The confirmations are also performed by ANSYS MAXWELL. The results show that the SSA is a good optimizer for these types of electric machines.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127895735","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}
F. Nees, Anastasios Katourtzidis, W. Kraft, Veronika Stahl, P. Vetter
Extended Abstract Metallic latent thermal energy storage systems are a promising technology for efficient storage of heat with a small foot print in volume and weight. Metallic phase change materials (mPCMs) are characterized by high energy densities and thermal conductivities [1, 2], which allow for fast thermal charging and discharging. These attributes make this kind of storage system attractive for mobile applications. High heat supply rates are required for battery electric vehicles under cold ambient conditions. In opposite to fuel cell or combustion driven engines, battery electric engines reject only little waste heat available for heating purposes. However, the usage of the battery for resistive heating or operation of a heat pump goes along with a reduction in range, which can be more than 50% at cold temperatures [3]. Therefore, a metallic latent thermal energy storage is a possible approach to solve this problem [4] and is currently considered in particular of interest for applications in battery electric buses.
{"title":"Experimental Investigation of Thermal Discharge Performance of a Metallic Latent Thermal Energy Storage System","authors":"F. Nees, Anastasios Katourtzidis, W. Kraft, Veronika Stahl, P. Vetter","doi":"10.11159/htff22.139","DOIUrl":"https://doi.org/10.11159/htff22.139","url":null,"abstract":"Extended Abstract Metallic latent thermal energy storage systems are a promising technology for efficient storage of heat with a small foot print in volume and weight. Metallic phase change materials (mPCMs) are characterized by high energy densities and thermal conductivities [1, 2], which allow for fast thermal charging and discharging. These attributes make this kind of storage system attractive for mobile applications. High heat supply rates are required for battery electric vehicles under cold ambient conditions. In opposite to fuel cell or combustion driven engines, battery electric engines reject only little waste heat available for heating purposes. However, the usage of the battery for resistive heating or operation of a heat pump goes along with a reduction in range, which can be more than 50% at cold temperatures [3]. Therefore, a metallic latent thermal energy storage is a possible approach to solve this problem [4] and is currently considered in particular of interest for applications in battery electric buses.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133219008","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}
- In this paper, the mineralogical characteristics of a weathered Platinum Group Minerals (PGMs) ore of Middle Group (1- 4) was investigated with the main objective of proposing a processing route for the ore. The oxidised PGM ore supplied was 60% passing 710µm and the major elements present were:Cr(27,03%), Fe(20,57%), Si(5,417%), Ca(5,43%), Mg(3,87) and Al(2,17 %). The ore was analysed for 4Es (Pt, Pd, Rh and Au) content using fire assaying followed by inductively coupled plasma - optical emission spectrometry. The results indicated that the grades of the 4Es were as follows: Au (0.04ppm), Pd (0.94ppm), Pt (1.98) and Rh (0.32). The Pd content is much lower than that of Pt, indicating Pd remobilization from the weathered zone to the lower zone which reduces the flotation efficiency by changing Pt:Pd ratio. The X-ray diffraction results indicated that the oxidised PGM ore sample was dominated by chromite, quartz, iron oxide minerals such magnesium/ferric iron, trevorite (nickel iron oxide) and secondary minerals such as covellite which is generally found in zones of secondary enrichment (supergene) of copper sulphide deposits. More mineralogical investigation is recommended such as Mineral Liberation Analysis in order to investigate the PGM’s grain size distribution, liberation and their associations. The body of work presented in this paper shows strong evidence that the PGM ore studied is weathered ore. The mineralogical study done on material showed oxidation and weathering as the probable causes of the low metallurgical performance of the ore. The results indicated there is an abundance of host minerals showing iron oxides minerals such as magnesium/ferric iron, trevorite (nickel iron oxide) and secondary minerals such as covellite which is generally found in zones of secondary enrichment (Supergene) of copper sulphide. The deposit has abundant amount of chromite and quartz. The fire assaying results indicated that the ore is low-grade and the Pd content is much lower than Pt, indicating Pd remobilization from the weathered zone to the lower zone which reduces the flotation efficiency by changing Pt:Pd ratio. More mineralogical investigation is recommended such as Mineral Liberation Analysis (MLA) to investigate the PGMs grain size distribution, their liberation and association.
{"title":"Investigating The Mineralogy Of An Oxidised South African PGM Ore From The Western Limb","authors":"M. Mailula, W. Nheta, C. Bhondayi","doi":"10.11159/mmme22.117","DOIUrl":"https://doi.org/10.11159/mmme22.117","url":null,"abstract":"- In this paper, the mineralogical characteristics of a weathered Platinum Group Minerals (PGMs) ore of Middle Group (1- 4) was investigated with the main objective of proposing a processing route for the ore. The oxidised PGM ore supplied was 60% passing 710µm and the major elements present were:Cr(27,03%), Fe(20,57%), Si(5,417%), Ca(5,43%), Mg(3,87) and Al(2,17 %). The ore was analysed for 4Es (Pt, Pd, Rh and Au) content using fire assaying followed by inductively coupled plasma - optical emission spectrometry. The results indicated that the grades of the 4Es were as follows: Au (0.04ppm), Pd (0.94ppm), Pt (1.98) and Rh (0.32). The Pd content is much lower than that of Pt, indicating Pd remobilization from the weathered zone to the lower zone which reduces the flotation efficiency by changing Pt:Pd ratio. The X-ray diffraction results indicated that the oxidised PGM ore sample was dominated by chromite, quartz, iron oxide minerals such magnesium/ferric iron, trevorite (nickel iron oxide) and secondary minerals such as covellite which is generally found in zones of secondary enrichment (supergene) of copper sulphide deposits. More mineralogical investigation is recommended such as Mineral Liberation Analysis in order to investigate the PGM’s grain size distribution, liberation and their associations. The body of work presented in this paper shows strong evidence that the PGM ore studied is weathered ore. The mineralogical study done on material showed oxidation and weathering as the probable causes of the low metallurgical performance of the ore. The results indicated there is an abundance of host minerals showing iron oxides minerals such as magnesium/ferric iron, trevorite (nickel iron oxide) and secondary minerals such as covellite which is generally found in zones of secondary enrichment (Supergene) of copper sulphide. The deposit has abundant amount of chromite and quartz. The fire assaying results indicated that the ore is low-grade and the Pd content is much lower than Pt, indicating Pd remobilization from the weathered zone to the lower zone which reduces the flotation efficiency by changing Pt:Pd ratio. More mineralogical investigation is recommended such as Mineral Liberation Analysis (MLA) to investigate the PGMs grain size distribution, their liberation and association.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129544303","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}
- Mechanized mining methods adopted in platinum-group elements (PGE) industry leads to mobile machinery leakages which result in mine sludge contamination by hydrocarbons. This paper aims at investigating the mineralogical characteristics of the contaminated mine sludge in comparison to the pristine ore. Two types of samples were used in the study were pristine PGE ore and contaminated PGE mine sludge. The samples were analysed using FTIR, XRF, XRD, SEM-EDS, Fire assaying, ICP-OES and Malvern PSD analyser for elemental composition, mineral composition, particle size distribution and the presence of hydrocarbon functional groups. FTIR results indicated the presence of a single C-H bonds in the contaminated mine sludge, which is the hydrocarbons functional group and pristine PGE ore was found to be free from an indication of such contaminants. The fire assaying results revealed that the mine sludge contained a total of 9.32g/t 4E (5.68 ppm Pt, 2.95ppm Pd, 0.6ppm Rh and 0.09ppm Au) and the pristine ore 4.74g/t 4E (2.64ppm Pt, 1.63ppm Pd, 0.42ppm Rh and 0.05ppm Au). SEM-EDS further confirmed that the sludge is indeed richer in PGE than pristine PGE ore. Mineral phases identified by XRD included millerite, chalcocite, aluminium oxide, chalcopyrite, pyrite, pyrrhotite, pentlandite, anorthite, enstatite and magnesium chromite and they were common to both samples. Particle size analysis revealed that the hydrocarbon contaminated mine sludge and the pristine ore had a P80 of 169 and 252µm respectively. Both samples had approximately 4% of fines (<10 µm). Remedial of hydrocarbon contaminants would lead to high grade PGE recovery.
-铂族元素(PGE)行业采用的机械化开采方法导致移动机械泄漏，导致矿山污泥被碳氢化合物污染。本文旨在研究污染矿山污泥与原始矿石的矿物学特征。研究中使用了两种类型的样品:原始PGE矿石和污染的PGE矿山污泥。采用FTIR、XRF、XRD、SEM-EDS、Fire分析、ICP-OES和Malvern PSD分析仪对样品进行了元素组成、矿物组成、粒度分布和烃官能团存在情况的分析。FTIR结果表明，在受污染的矿山污泥中存在单个C-H键，这是碳氢化合物的官能团，并且发现原始PGE矿石没有这种污染物的迹象。测定结果表明，该矿污泥中共含9.32g/t 4E (5.68 ppm Pt、2.95ppm Pd、0.6ppm Rh和0.09ppm Au)，原始矿石中含4.74g/t 4E (2.64ppm Pt、1.63ppm Pd、0.42ppm Rh和0.05ppm Au)。SEM-EDS进一步证实了污泥中PGE的含量确实比原始的PGE矿石更丰富。通过XRD鉴定的矿物相包括千粒矿、辉铜矿、氧化铝、黄铜矿、黄铁矿、磁黄铁矿、镍黄铁矿、钙长石、辉辉石和镁铬铁矿，它们在两个样品中都是常见的。粒度分析表明，烃污染污泥的P80为169µm，原始矿石的P80为252µm。两种样品都有大约4%的细粒(<10µm)。对烃类污染物进行治理，可实现高品位PGE的回收。
{"title":"Characterization of Hydrocarbons Contaminated Platinum Group Metals Mine Sludge from the Bushveld Complex","authors":"Elelwanir M. S Mavhungu, W. Nheta, D. Rose","doi":"10.11159/mmme22.116","DOIUrl":"https://doi.org/10.11159/mmme22.116","url":null,"abstract":"- Mechanized mining methods adopted in platinum-group elements (PGE) industry leads to mobile machinery leakages which result in mine sludge contamination by hydrocarbons. This paper aims at investigating the mineralogical characteristics of the contaminated mine sludge in comparison to the pristine ore. Two types of samples were used in the study were pristine PGE ore and contaminated PGE mine sludge. The samples were analysed using FTIR, XRF, XRD, SEM-EDS, Fire assaying, ICP-OES and Malvern PSD analyser for elemental composition, mineral composition, particle size distribution and the presence of hydrocarbon functional groups. FTIR results indicated the presence of a single C-H bonds in the contaminated mine sludge, which is the hydrocarbons functional group and pristine PGE ore was found to be free from an indication of such contaminants. The fire assaying results revealed that the mine sludge contained a total of 9.32g/t 4E (5.68 ppm Pt, 2.95ppm Pd, 0.6ppm Rh and 0.09ppm Au) and the pristine ore 4.74g/t 4E (2.64ppm Pt, 1.63ppm Pd, 0.42ppm Rh and 0.05ppm Au). SEM-EDS further confirmed that the sludge is indeed richer in PGE than pristine PGE ore. Mineral phases identified by XRD included millerite, chalcocite, aluminium oxide, chalcopyrite, pyrite, pyrrhotite, pentlandite, anorthite, enstatite and magnesium chromite and they were common to both samples. Particle size analysis revealed that the hydrocarbon contaminated mine sludge and the pristine ore had a P80 of 169 and 252µm respectively. Both samples had approximately 4% of fines (<10 µm). Remedial of hydrocarbon contaminants would lead to high grade PGE recovery.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131054135","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}
– Dapped-end beams (DEBs), commonly known as half joint beams, are broadly used in bridge constructions. The reduction of the depth at the supports of the beam makes it a critical shear area and vulnerable to damage. Being used primarily on bridges, dapped-end beams are susceptible to dynamic impact loading, which is more brutal than static load cases. Various reinforcement configurations combined with different concrete properties were used to withstand the stresses generated by such loadings and mitigate their effect on the critical shear location. To reduce the extensive work and use of resources required to investigate such problems, numerical investigations were conducted on LS-DYNA software to anticipate the enhancement in the shear capacity as a function of compressive strength, main reinforcement, and shear hanger reinforcement configurations. Multi-criteria decision-making using TOPSIS analysis was conducted to choose the best scenario configuration that maximizes the beam’s performance under dynamic impact loading. TOPSIS analysis was based on the deflection of the beam, shear strength of the concrete, and stress and strain of main and hanger reinforcement.
{"title":"Optimum Design Configuration of Dapped-End Beam Under Dynamic Loading Using TOPSIS Method","authors":"E. Hijah, O. Najm, Hilal El-Hassan, Z. Syed","doi":"10.11159/mmme22.106","DOIUrl":"https://doi.org/10.11159/mmme22.106","url":null,"abstract":"– Dapped-end beams (DEBs), commonly known as half joint beams, are broadly used in bridge constructions. The reduction of the depth at the supports of the beam makes it a critical shear area and vulnerable to damage. Being used primarily on bridges, dapped-end beams are susceptible to dynamic impact loading, which is more brutal than static load cases. Various reinforcement configurations combined with different concrete properties were used to withstand the stresses generated by such loadings and mitigate their effect on the critical shear location. To reduce the extensive work and use of resources required to investigate such problems, numerical investigations were conducted on LS-DYNA software to anticipate the enhancement in the shear capacity as a function of compressive strength, main reinforcement, and shear hanger reinforcement configurations. Multi-criteria decision-making using TOPSIS analysis was conducted to choose the best scenario configuration that maximizes the beam’s performance under dynamic impact loading. TOPSIS analysis was based on the deflection of the beam, shear strength of the concrete, and stress and strain of main and hanger reinforcement.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131485416","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}
Sandeep Aryal, Mohammad Abutayehb, Young-Min Kim, Kwang-Woon Jeong
A lab-scale organic Rankine cycle has equipped a Low Temperature Evaporator (LTE) for water recovery in addition to the High Temperature Evaporator (HTE) for heat recovery. The recovered water is reused as the make-up water line to save the fresh water consumption in the cooling tower [1, 2]. Water recovery efficiency was defined as the ratio of the water condensation rate from the flue gas side to the moisture flowrate at the flue gas inlet [3]. The LTE as cross flow heat exchanger is to recover water in condensate form from the combustion flue gas in the duct side while the recovered latent and sensible heats are transferred into the refrigerant R134a in the tube side. The LTE involves complicated phenomena since the condensation of water vapour in the flue gas duct side and the flow boiling of R134a in tube side were taken place simultaneously. Design of a LTE and its optimized operation depend on a knowledge and understanding of the heat and mass transfer occurred in the LTE. Analytical modelling would be essential to derive the critical parameters for design and operation to achieve the goal of the organic Rankine cycle. The objective of this research was to develop an analytical modelling for simulating the simultaneous phase transitions: 1) condensation of water vapour in the duct side and 2) flow boiling of the refrigerant R134a in the tube side. The control volume was confined to the LTE with two working fluids including the combustion flue gas in the duct side and R134a in the tube side. The work scope was to conduct derivations of the governing equations and numerical algorithm, program development, validations and verifications, and extensive case studies. The modelling was able to generate the spatial profiles of temperature and heat transfer coefficients of both sides, vapour quality of R134a, and condensation rate of water vapour in flue gas side, etc. The mean absolute deviation between the calculated and measured heat transfer coefficients was within 18 %. The calculated data including exit temperature of flue gas and R134a, and water recovery efficiency were in good agreement with the measured data within 15 %. The case studies with the developed software were conducted to examine the roles of sensible and latent heat transfer in flue gas side and boiling impact of R134a side with variations of design and operating parameters including heat transfer area, and inlet conditions of flue gas and R134a, etc. The performance was compared with the case of water coolant under same conditions. The results show that the water recovery efficiency was able to enhance from the current 50 wt% to 77 wt% as expanding its total heat transfer area up to 4 times than the baseline dimension. It was found that the ratio of mass flow rate of the coolant to flue gas was a strong function to improve the water recovery efficiency due to the higher heat transfer coefficients in R134a side induced from the flow boiling. The comparison case study predicted
{"title":"Analytical Modelling on Simultaneous Phase Transitions in Low Temperature Evaporator for Organic Rankine Cycle Applications","authors":"Sandeep Aryal, Mohammad Abutayehb, Young-Min Kim, Kwang-Woon Jeong","doi":"10.11159/htff22.131","DOIUrl":"https://doi.org/10.11159/htff22.131","url":null,"abstract":"A lab-scale organic Rankine cycle has equipped a Low Temperature Evaporator (LTE) for water recovery in addition to the High Temperature Evaporator (HTE) for heat recovery. The recovered water is reused as the make-up water line to save the fresh water consumption in the cooling tower [1, 2]. Water recovery efficiency was defined as the ratio of the water condensation rate from the flue gas side to the moisture flowrate at the flue gas inlet [3]. The LTE as cross flow heat exchanger is to recover water in condensate form from the combustion flue gas in the duct side while the recovered latent and sensible heats are transferred into the refrigerant R134a in the tube side. The LTE involves complicated phenomena since the condensation of water vapour in the flue gas duct side and the flow boiling of R134a in tube side were taken place simultaneously. Design of a LTE and its optimized operation depend on a knowledge and understanding of the heat and mass transfer occurred in the LTE. Analytical modelling would be essential to derive the critical parameters for design and operation to achieve the goal of the organic Rankine cycle. The objective of this research was to develop an analytical modelling for simulating the simultaneous phase transitions: 1) condensation of water vapour in the duct side and 2) flow boiling of the refrigerant R134a in the tube side. The control volume was confined to the LTE with two working fluids including the combustion flue gas in the duct side and R134a in the tube side. The work scope was to conduct derivations of the governing equations and numerical algorithm, program development, validations and verifications, and extensive case studies. The modelling was able to generate the spatial profiles of temperature and heat transfer coefficients of both sides, vapour quality of R134a, and condensation rate of water vapour in flue gas side, etc. The mean absolute deviation between the calculated and measured heat transfer coefficients was within 18 %. The calculated data including exit temperature of flue gas and R134a, and water recovery efficiency were in good agreement with the measured data within 15 %. The case studies with the developed software were conducted to examine the roles of sensible and latent heat transfer in flue gas side and boiling impact of R134a side with variations of design and operating parameters including heat transfer area, and inlet conditions of flue gas and R134a, etc. The performance was compared with the case of water coolant under same conditions. The results show that the water recovery efficiency was able to enhance from the current 50 wt% to 77 wt% as expanding its total heat transfer area up to 4 times than the baseline dimension. It was found that the ratio of mass flow rate of the coolant to flue gas was a strong function to improve the water recovery efficiency due to the higher heat transfer coefficients in R134a side induced from the flow boiling. The comparison case study predicted","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129200641","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}
R. Rodrígueza, Patricia Patricia, Cristóbal Lombardíab, Marc Bascomptac
- Ground vibrations due to blasting can cause damage to nearby structures. Damage prevention criteria have been developed to avoid this potential risk, demonstrating a limit value for the peak particle velocity (PPV) as a function of ground natural frequency and type of structure to protect. In addition, several empirical attenuation laws to estimate PPV and frequency as a function of distance and the amount of explosive used were also developed. These models can be used to predict, separately, PPV and frequency, obtaining the representative point in the damage prevention abacus of the designed blast and decide if a potential damage could exist or not. In a previous work, the authors have proposed a procedure to define not a point but an area representative of the risk in the abacus of damage criteria. The procedure was developed for blasting in limestone quarries working simultaneously with the PPV and frequency attenuation laws. The present work demonstrates that the method can be used for other types of limestone blasts. Thus, several blasting operations were monitored on limestone materials in an open-pit gold mine. Verifying the goodness of the new method proposed.
{"title":"Analysis of Blasting Vibrations Produced In a Gold Mine Using the Damage Prevention Abacus","authors":"R. Rodrígueza, Patricia Patricia, Cristóbal Lombardíab, Marc Bascomptac","doi":"10.11159/mmme22.122","DOIUrl":"https://doi.org/10.11159/mmme22.122","url":null,"abstract":"- Ground vibrations due to blasting can cause damage to nearby structures. Damage prevention criteria have been developed to avoid this potential risk, demonstrating a limit value for the peak particle velocity (PPV) as a function of ground natural frequency and type of structure to protect. In addition, several empirical attenuation laws to estimate PPV and frequency as a function of distance and the amount of explosive used were also developed. These models can be used to predict, separately, PPV and frequency, obtaining the representative point in the damage prevention abacus of the designed blast and decide if a potential damage could exist or not. In a previous work, the authors have proposed a procedure to define not a point but an area representative of the risk in the abacus of damage criteria. The procedure was developed for blasting in limestone quarries working simultaneously with the PPV and frequency attenuation laws. The present work demonstrates that the method can be used for other types of limestone blasts. Thus, several blasting operations were monitored on limestone materials in an open-pit gold mine. Verifying the goodness of the new method proposed.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133631700","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}
Semran Ipek, Kiril S. Shterev, S. Stefanov, A. Dinler
Extended Abstract The breakdown of the momentum transfer at a fluid-solid contact has been known in micro/nanofluidics for many years. Influence of the surface shape (i.e. convex/concave) has been investigated in gas-phase flows [1-2]. On the other hand, thermal boundary resistance is a known phenomenon, which reduces the heat transfer between heterogeneous materials and affects overall thermal performance, has not been investigated sufficiently well at curved interfaces. The present study runs non-equilibrium molecular dynamics (NEMD) simulations and considers a thin heated cylindrical shell, which is located in the middle of the gap between two coaxial stationary cylinders, in order to investigate the thermal boundary resistance. In contrast to previous molecular dynamics simulations [3-4], realistic walls are created to examine the interfacial heat transfer related to the surface curvature over rough and smooth surfaces. The results show the existence of the opposing effect of curvature. This effect demonstrates itself by increasing heat transfer from a hot concave surface to the fluid with curvature, while, in contrast, by decreasing heat transfer from a hot convex surface. At identical curvature and surface area, the present results show that the thermal resistance between a hot convex silver surface and liquid argon is larger than the thermal resistance between a hot concave silver surface and liquid argon. In addition,
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- The excellent properties of nanotwinned structures have been a hot area of research in recent years. Silver (Ag) has the lowest stacking fault energy (SFE) among all FCC metals, which has a strong tendency to form a twin structure. Also, sapphire substrates are ideal for use in LED applications due to high-temperature resistance, high strength, good electrical insulations, and low dielectric loss. Depositing Ag nanotwinned films on sapphire substrates can serve as a perfect candidate for die bonding in LED manufacturing. In this study, two deposition methods had been demonstrated for the fabrication of high density (111)-textured Ag nanotwinned films on sapphire wafers. Microstructural analyses show that both the sputtered and evaporated Ag grains presented a high density of twin structure. The cross-sectional EBSD analysis of the sputtered Ag nanotwinned film indicated a highly (111)-preferred orientation to 34.6% of the overall grains. Further, the sputtering process allows the production of surface roughness of the Ag nanotwinned film up to 65.1 nm. The epitaxial growth of Ag nanotwinned films with (111)-preferred orientation can be utilized by both the deposition methods.
{"title":"Sputtering and Evaporating of High Density (111)-textured Ag Nanotwinned Films on Sapphire Wafers","authors":"Yin-Hsuan Chen, Pei-Ing Lee, T. Chuang","doi":"10.11159/mmme22.120","DOIUrl":"https://doi.org/10.11159/mmme22.120","url":null,"abstract":"- The excellent properties of nanotwinned structures have been a hot area of research in recent years. Silver (Ag) has the lowest stacking fault energy (SFE) among all FCC metals, which has a strong tendency to form a twin structure. Also, sapphire substrates are ideal for use in LED applications due to high-temperature resistance, high strength, good electrical insulations, and low dielectric loss. Depositing Ag nanotwinned films on sapphire substrates can serve as a perfect candidate for die bonding in LED manufacturing. In this study, two deposition methods had been demonstrated for the fabrication of high density (111)-textured Ag nanotwinned films on sapphire wafers. Microstructural analyses show that both the sputtered and evaporated Ag grains presented a high density of twin structure. The cross-sectional EBSD analysis of the sputtered Ag nanotwinned film indicated a highly (111)-preferred orientation to 34.6% of the overall grains. Further, the sputtering process allows the production of surface roughness of the Ag nanotwinned film up to 65.1 nm. The epitaxial growth of Ag nanotwinned films with (111)-preferred orientation can be utilized by both the deposition methods.","PeriodicalId":385356,"journal":{"name":"Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128185497","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}
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