The application of the elements of the Fourth Industrial Revolution (4IR) through the development of a Flexible Manufacturing System (FMS) for manufacturing operations in the railcar industry will promote flexibility, intelligent coordination of the manufacturing operations, efficient handling and quality control. Some production systems in the railcar industry are non-responsive to changes in real time thereby leading to reduction in productivity, hence, the need for a FMS that will cater for the dynamics of manufacturing operation. This work proposes a FMS, which encompasses the assembly line, lean production, logistics and quality assurance. The system comprises of the Radio Frequency Identification Technology (RFID) for components identification and process control, arrays of sensors and cameras, automated material storage and supply, standard interfaces such as the interface for the internet of things (IoT), the robotic welding system as well as a robust intelligent control system. A framework for the implementation of the FMS was developed while the simulation of the designed system was performed using the Anylogic 8.2.3. software. Based on the results obtained, there was an inverse relationship between the operating cycle time of the conveyor and the conveyor speed per cycle when the conveyor’s performance was simulated at a speed of 3 m/s and 7 m/s. The results showed that the system can suitably perform the sequence of assembly and quality assurance operations during the manufacturing of railcar subassemblies with minimal interruptions and human intervention. This will promote production of component parts with high structural and dimensional integrity with significant reduction in the manufacturing cycle time and cost.
{"title":"Design and simulation of a flexible manufacturing system for manufacturing operations of railcar subassemblies","authors":"Ilesanmi Daniyan , Khumbulani Mpofu , Boitumelo Ramatsetse , Emanuel Zeferino , Giovani Monzambe , Elvis Sekano","doi":"10.1016/j.promfg.2021.07.018","DOIUrl":"10.1016/j.promfg.2021.07.018","url":null,"abstract":"<div><p>The application of the elements of the Fourth Industrial Revolution (4IR) through the development of a Flexible Manufacturing System (FMS) for manufacturing operations in the railcar industry will promote flexibility, intelligent coordination of the manufacturing operations, efficient handling and quality control. Some production systems in the railcar industry are non-responsive to changes in real time thereby leading to reduction in productivity, hence, the need for a FMS that will cater for the dynamics of manufacturing operation. This work proposes a FMS, which encompasses the assembly line, lean production, logistics and quality assurance. The system comprises of the Radio Frequency Identification Technology (RFID) for components identification and process control, arrays of sensors and cameras, automated material storage and supply, standard interfaces such as the interface for the internet of things (IoT), the robotic welding system as well as a robust intelligent control system. A framework for the implementation of the FMS was developed while the simulation of the designed system was performed using the Anylogic 8.2.3. software. Based on the results obtained, there was an inverse relationship between the operating cycle time of the conveyor and the conveyor speed per cycle when the conveyor’s performance was simulated at a speed of 3 m/s and 7 m/s. The results showed that the system can suitably perform the sequence of assembly and quality assurance operations during the manufacturing of railcar subassemblies with minimal interruptions and human intervention. This will promote production of component parts with high structural and dimensional integrity with significant reduction in the manufacturing cycle time and cost.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"54 ","pages":"Pages 112-117"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.promfg.2021.07.018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54984901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.07.043
Jianmin Wang , Yingguang Li , Jiaqi Hua , Changqing Liu , Xiaozhong Hao
Tool wear prediction is of significance in advanced manufacturing industries, as it aims to ensure the quality of parts, improve machining efficiency and reduce machining costs. Existing tool wear monitoring and prediction methods mainly adopt neural network model with fixed architecture, which rely on the researchers’ experience and cannot guarantee accuracy under different cutting conditions. This paper proposes a tool wear prediction method based on network architecture search. which can learn a suitable network structure under different cutting conditions. Experiments shows sufficient improvement in the accuracy of predicting tool wear compared with existing methods.
{"title":"An accurate tool wear prediction method under different cutting conditions based on network architecture search","authors":"Jianmin Wang , Yingguang Li , Jiaqi Hua , Changqing Liu , Xiaozhong Hao","doi":"10.1016/j.promfg.2021.07.043","DOIUrl":"10.1016/j.promfg.2021.07.043","url":null,"abstract":"<div><p>Tool wear prediction is of significance in advanced manufacturing industries, as it aims to ensure the quality of parts, improve machining efficiency and reduce machining costs. Existing tool wear monitoring and prediction methods mainly adopt neural network model with fixed architecture, which rely on the researchers’ experience and cannot guarantee accuracy under different cutting conditions. This paper proposes a tool wear prediction method based on network architecture search. which can learn a suitable network structure under different cutting conditions. Experiments shows sufficient improvement in the accuracy of predicting tool wear compared with existing methods.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"54 ","pages":"Pages 274-278"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.promfg.2021.07.043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54985201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.10.024
Lennart Späker, Benedikt G. Mark, Erwin Rauch
This paper focuses on the complex selection process of worker assistance systems for human-centered manufacturing systems. Due to rising complexity of products and processes in the manufacturing sector, as well as changing work environments, the choice for suitable support systems on the shop floor becomes more difficult. The selection of worker assistance systems is yet not well studied and there is a lack in scientifically based methodologies to assist designers of manufacturing systems in this process. In this work we identify a broad variety of influencing attributes for selecting the most appropriate worker assistance systems depending on each individual field of application. These attributes are building the ground for the development of a morphological box to facilitate the selection process of worker assistance systems. The proposed procedure to use the morphological box is finally explained with a practical example.
{"title":"Development of a Morphological Box to Describe Worker Assistance Systems in Manufacturing","authors":"Lennart Späker, Benedikt G. Mark, Erwin Rauch","doi":"10.1016/j.promfg.2021.10.024","DOIUrl":"10.1016/j.promfg.2021.10.024","url":null,"abstract":"<div><p>This paper focuses on the complex selection process of worker assistance systems for human-centered manufacturing systems. Due to rising complexity of products and processes in the manufacturing sector, as well as changing work environments, the choice for suitable support systems on the shop floor becomes more difficult. The selection of worker assistance systems is yet not well studied and there is a lack in scientifically based methodologies to assist designers of manufacturing systems in this process. In this work we identify a broad variety of influencing attributes for selecting the most appropriate worker assistance systems depending on each individual field of application. These attributes are building the ground for the development of a morphological box to facilitate the selection process of worker assistance systems. The proposed procedure to use the morphological box is finally explained with a practical example.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 168-175"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002213/pdf?md5=fdecfb7cf3bea32c52b98dd166d635ad&pid=1-s2.0-S2351978921002213-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54985936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.10.071
Aleksandra Dewicka-Olszewska
Active involvement of entrepreneurs in the development and implementation of innovations is associated with the ability to use all external and internal human, material, capital and information resources, and this is associated with innovative maturity. This is determined by the level of organizational culture that uses the entrepreneurial sense, creativity and other abilities to create and implement innovations, including ergonomic innovations. Ergonomic innovations integrate the achievements of many sciences humanizing the work and life environment so that they are friendly to the psychophysical needs of the user. Small and mediumsized enterprises play an extremely important role in the Polish economy (enterprises in the territory of the Republic of Poland), constituting a strong group of 99.8% of all economic entities operating on the market. In this article, qualitative studies of ergonomic innovations have been made on the basis of complex online and paper surveys. The results of the conducted research and analyzes on ergonomic innovations can be assessed both in the substantive and utilitarian level, and the value of the article is its contribution to the development of innovation management.
{"title":"Application and role of ergonomic innovations in small and medium-sized enterprises","authors":"Aleksandra Dewicka-Olszewska","doi":"10.1016/j.promfg.2021.10.071","DOIUrl":"10.1016/j.promfg.2021.10.071","url":null,"abstract":"<div><p>Active involvement of entrepreneurs in the development and implementation of innovations is associated with the ability to use all external and internal human, material, capital and information resources, and this is associated with innovative maturity. This is determined by the level of organizational culture that uses the entrepreneurial sense, creativity and other abilities to create and implement innovations, including ergonomic innovations. Ergonomic innovations integrate the achievements of many sciences humanizing the work and life environment so that they are friendly to the psychophysical needs of the user. Small and mediumsized enterprises play an extremely important role in the Polish economy (enterprises in the territory of the Republic of Poland), constituting a strong group of 99.8% of all economic entities operating on the market. In this article, qualitative studies of ergonomic innovations have been made on the basis of complex online and paper surveys. The results of the conducted research and analyzes on ergonomic innovations can be assessed both in the substantive and utilitarian level, and the value of the article is its contribution to the development of innovation management.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 521-526"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002687/pdf?md5=336e275f9753ebe933a83b4f446c9fb9&pid=1-s2.0-S2351978921002687-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54986434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.10.076
Roland Schmuck
Various studies confirm the positive outcomes of business simulation games, which can be effectively used in the education of manufacturing and supply chain processes. The use of them in education increases business knowledge, causes better understanding of business processes, improves decision making, problem-solving, and interpersonal communication skills. General business simulation games with manufacturing functions included are described briefly. Twenty-two specialized manufacturing and supply chain simulations are discussed in detail showing their features and decision-making possibilities. The study is useful for educators, trainers, and companies looking for practical learning methods. The discussion of the games gives them an opportunity to better understand available business simulations and be able to choose the appropriate one for their expected learning outcomes.
{"title":"Education and training of manufacturing and supply chain processes using business simulation games","authors":"Roland Schmuck","doi":"10.1016/j.promfg.2021.10.076","DOIUrl":"10.1016/j.promfg.2021.10.076","url":null,"abstract":"<div><p>Various studies confirm the positive outcomes of business simulation games, which can be effectively used in the education of manufacturing and supply chain processes. The use of them in education increases business knowledge, causes better understanding of business processes, improves decision making, problem-solving, and interpersonal communication skills. General business simulation games with manufacturing functions included are described briefly. Twenty-two specialized manufacturing and supply chain simulations are discussed in detail showing their features and decision-making possibilities. The study is useful for educators, trainers, and companies looking for practical learning methods. The discussion of the games gives them an opportunity to better understand available business simulations and be able to choose the appropriate one for their expected learning outcomes.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 555-562"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002730/pdf?md5=2a07af327dcb375a4a9b32eb20ac0c59&pid=1-s2.0-S2351978921002730-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54986503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.07.039
Aoife C. Doyle , Darragh S. Egan , Caitríona M. Ryan , Andrew C. Parnell , Denis P. Dowling
This study investigates the use of a statistical anomaly detection method to analyse in-situ process monitoring data obtained during the Laser-Powder Bed Fusion of Ti-6Al-4V parts. The printing study was carried out on a Renishaw 500M Laser-Powder Bed Fusion system. A photodiode-based system called InfiniAM was used to monitor the melt-pool emissions along with the operational behaviour of the laser during the build process. The analysis of the in-process data was carried out using an unsupervised machine learning approach called the Search and TRace AnomalY algorithm. The ability to detect defects during the manufacturing of metal alloy parts was demonstrated.
{"title":"Application of the STRAY statistical learning algorithm for the evaluation of in-situ process monitoring data during L-PBF additive manufacturing.","authors":"Aoife C. Doyle , Darragh S. Egan , Caitríona M. Ryan , Andrew C. Parnell , Denis P. Dowling","doi":"10.1016/j.promfg.2021.07.039","DOIUrl":"10.1016/j.promfg.2021.07.039","url":null,"abstract":"<div><p>This study investigates the use of a statistical anomaly detection method to analyse in-situ process monitoring data obtained during the Laser-Powder Bed Fusion of Ti-6Al-4V parts. The printing study was carried out on a Renishaw 500M Laser-Powder Bed Fusion system. A photodiode-based system called InfiniAM was used to monitor the melt-pool emissions along with the operational behaviour of the laser during the build process. The analysis of the in-process data was carried out using an unsupervised machine learning approach called the Search and TRace AnomalY algorithm. The ability to detect defects during the manufacturing of metal alloy parts was demonstrated.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"54 ","pages":"Pages 250-256"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.promfg.2021.07.039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54985151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.10.060
Anis Assad Neto , Bruna Sprea Carrijo , João Guilherme Romanzini Brock , Fernando Deschamps , Edson Pinheiro de Lima
Preventive maintenance interventions are scheduled in industrial systems to prevent machine failures and breakdowns, which are associated with the incurrence of repair, unavailability, and quality-related costs. The execution of such interventions, however, generally represents a penalty to a manufacturing system’s production throughput due to machine interruption requirements. By the use of a digital twin architecture, we develop a decision support system to schedule preventive maintenance interventions with the aim of minimizing production throughout penalties via the exploitation of real-time opportunities such as supply shortages, momentary machine idleness or machine breakdowns. The decision support system has its application demonstrated by a case in a furniture manufacturer in the State of Santa Catarina – Brazil.
{"title":"Digital twin-driven decision support system for opportunistic preventive maintenance scheduling in manufacturing","authors":"Anis Assad Neto , Bruna Sprea Carrijo , João Guilherme Romanzini Brock , Fernando Deschamps , Edson Pinheiro de Lima","doi":"10.1016/j.promfg.2021.10.060","DOIUrl":"10.1016/j.promfg.2021.10.060","url":null,"abstract":"<div><p>Preventive maintenance interventions are scheduled in industrial systems to prevent machine failures and breakdowns, which are associated with the incurrence of repair, unavailability, and quality-related costs. The execution of such interventions, however, generally represents a penalty to a manufacturing system’s production throughput due to machine interruption requirements. By the use of a digital twin architecture, we develop a decision support system to schedule preventive maintenance interventions with the aim of minimizing production throughout penalties via the exploitation of real-time opportunities such as supply shortages, momentary machine idleness or machine breakdowns. The decision support system has its application demonstrated by a case in a furniture manufacturer in the State of Santa Catarina – Brazil.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 439-446"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002572/pdf?md5=38431966ee069d2e6d74e735d719d42d&pid=1-s2.0-S2351978921002572-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54985910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Efficient material supply is a key requirement for production and assembly processes, but the related planning process is complex due to different factors influencing internal material provision. Different strategies and techniques for storage, order picking and transportation of components as well as for material flow control exist. In this paper, a holistic approach for planning, analyzing and evaluating internal material provision is introduced, influencing factors are revealed and a brief planning guideline is presented. An evaluation approach is pointed out based on qualitative, quantitative and monetary aspects. Finally, the planning approach is applied in a specific use case analyzing different planning variants such as line stocking, kitting and a hybrid solution for material provision at assembly stations in medical technology industry.
{"title":"A systematic approach for planning, analyzing and evaluating internal material provision","authors":"Meike Herbert , Pascal Heinlein , Jens Fürst , Jörg Franke","doi":"10.1016/j.promfg.2021.10.061","DOIUrl":"10.1016/j.promfg.2021.10.061","url":null,"abstract":"<div><p>Efficient material supply is a key requirement for production and assembly processes, but the related planning process is complex due to different factors influencing internal material provision. Different strategies and techniques for storage, order picking and transportation of components as well as for material flow control exist. In this paper, a holistic approach for planning, analyzing and evaluating internal material provision is introduced, influencing factors are revealed and a brief planning guideline is presented. An evaluation approach is pointed out based on qualitative, quantitative and monetary aspects. Finally, the planning approach is applied in a specific use case analyzing different planning variants such as line stocking, kitting and a hybrid solution for material provision at assembly stations in medical technology industry.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 447-454"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002584/pdf?md5=1b5fdde2183285ff8296f8bdff73716e&pid=1-s2.0-S2351978921002584-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54985922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1016/j.promfg.2021.10.035
Sepideh Abolghasem , Luis Felipe Hernández Rivera , Shashank Shekhar
Ultrafine-grained (UFG) microstructure of Cu processed by large strain machining (LSM) is explored in order to create highly refined grain structures to achieve the highest strength while postponing the available nuclei for future recrystallization. The optimum solution is obtained theoretically using the Strength Pareto Evolutionary Algorithm (SPEA) and empirically using LSM. The thermal stability of the optimal solution is verified across the comparable LSM conditions using isothermal annealing curve. We also studied the kinetics of crystallization on the optimal solution using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory. The optimal solution encountered leads to the latest time for the point where hardness start decline among a comparable sample conditions and lower the rate constant (1/τ) among LSM conditions.
{"title":"Optimizing the metastability of high-strength ultrafine grained microstructure from large strain machining","authors":"Sepideh Abolghasem , Luis Felipe Hernández Rivera , Shashank Shekhar","doi":"10.1016/j.promfg.2021.10.035","DOIUrl":"10.1016/j.promfg.2021.10.035","url":null,"abstract":"<div><p>Ultrafine-grained (UFG) microstructure of Cu processed by large strain machining (LSM) is explored in order to create highly refined grain structures to achieve the highest strength while postponing the available nuclei for future recrystallization. The optimum solution is obtained theoretically using the Strength Pareto Evolutionary Algorithm (SPEA) and empirically using LSM. The thermal stability of the optimal solution is verified across the comparable LSM conditions using isothermal annealing curve. We also studied the kinetics of crystallization on the optimal solution using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory. The optimal solution encountered leads to the latest time for the point where hardness start decline among a comparable sample conditions and lower the rate constant (1/τ) among LSM conditions.</p></div>","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"55 ","pages":"Pages 247-252"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2351978921002328/pdf?md5=51a66d97cc700cbdafd109fdf7cf47ac&pid=1-s2.0-S2351978921002328-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54986070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1036/1097-8542.196000
Jeffrey H Williams
Geometry has surprising consequences for the behaviour of matter. Living in three dimensions, we’re familiar with liquids that abruptly freeze into solids, or crystals under pressure that suddenly alter their molecular structures. Confine the same materials within a narrow, roughly one-dimensional (1D) wire, and everything changes. In one dimension, molecular interactions can’t overcome the disrupting influence of noise to create long-range order; liquids won’t freeze at any temperature. We know this from the theory of critical phenomena, which also reveals why geometry is so important — in effect, it controls the crucial supply lines for the forces of order in their battle against disrupting noise. In one dimension, one end of a chain can influence the other end only by interactions transmitted directly along the chain, so any disruption is necessarily ‘in the way’ and destroys the linking of behaviour in distant parts. In two or more dimensions, multiple paths connect any two points, and the number of possible paths grows rapidly with increasing dimension. Order then emerges out of chaos more readily. Clearly, all this has more to do with simple geometry than physics, and unsurprisingly its implications are evident elsewhere. A good example arises in evolutionary theory, especially in the effort to extend classical population genetics beyond the simplifying assumptions of early theorists such as Motoo Kimura or Ronald Fisher. They were mostly limited to studying evolution in ‘well mixed’ populations, in which each individual interacts in equal likelihood with any other, such as bacteria interacting in a well-stirred liquid. This assumption makes the maths easier, but is rarely, if ever, true in reality. Organisms often don’t move around enough to interact with more than a small fraction of others that live nearby. More generally, evolution itself, or the environment, frequently stirs up spatial structure by sorting genetic types preferentially into some regions, thereby strongly skewing subsequent interactions away from the well-mixed ideal. What does this have to do with dimension? As several researchers have recently noted, such departures from the well-mixed ideal frequently arise in situations in which evolution works in a lower-dimensional setting. In physics, ‘well mixed’ translates more or less as ‘mean field’, and mean field theory works well above a certain critical dimension, where noise and fluctuations have less influence. Below this dimension, we also know, it can be wildly inaccurate. One of the most common situations, as Kirill Korolev et al. discuss (Rev. Mod. Phys. 82, 1691–1718; 2010), emerges out of the expansion of a population. Say a bacterial colony is expanding by growth into a new food source. In the simplest picture of roughly circular surface growth, individuals at the expanding front exist in a roughly 1D world; they’re almost certainly the offspring of other individuals living in the same front. Experiments show that
{"title":"Dimensional Analysis","authors":"Jeffrey H Williams","doi":"10.1036/1097-8542.196000","DOIUrl":"https://doi.org/10.1036/1097-8542.196000","url":null,"abstract":"Geometry has surprising consequences for the behaviour of matter. Living in three dimensions, we’re familiar with liquids that abruptly freeze into solids, or crystals under pressure that suddenly alter their molecular structures. Confine the same materials within a narrow, roughly one-dimensional (1D) wire, and everything changes. In one dimension, molecular interactions can’t overcome the disrupting influence of noise to create long-range order; liquids won’t freeze at any temperature. We know this from the theory of critical phenomena, which also reveals why geometry is so important — in effect, it controls the crucial supply lines for the forces of order in their battle against disrupting noise. In one dimension, one end of a chain can influence the other end only by interactions transmitted directly along the chain, so any disruption is necessarily ‘in the way’ and destroys the linking of behaviour in distant parts. In two or more dimensions, multiple paths connect any two points, and the number of possible paths grows rapidly with increasing dimension. Order then emerges out of chaos more readily. Clearly, all this has more to do with simple geometry than physics, and unsurprisingly its implications are evident elsewhere. A good example arises in evolutionary theory, especially in the effort to extend classical population genetics beyond the simplifying assumptions of early theorists such as Motoo Kimura or Ronald Fisher. They were mostly limited to studying evolution in ‘well mixed’ populations, in which each individual interacts in equal likelihood with any other, such as bacteria interacting in a well-stirred liquid. This assumption makes the maths easier, but is rarely, if ever, true in reality. Organisms often don’t move around enough to interact with more than a small fraction of others that live nearby. More generally, evolution itself, or the environment, frequently stirs up spatial structure by sorting genetic types preferentially into some regions, thereby strongly skewing subsequent interactions away from the well-mixed ideal. What does this have to do with dimension? As several researchers have recently noted, such departures from the well-mixed ideal frequently arise in situations in which evolution works in a lower-dimensional setting. In physics, ‘well mixed’ translates more or less as ‘mean field’, and mean field theory works well above a certain critical dimension, where noise and fluctuations have less influence. Below this dimension, we also know, it can be wildly inaccurate. One of the most common situations, as Kirill Korolev et al. discuss (Rev. Mod. Phys. 82, 1691–1718; 2010), emerges out of the expansion of a population. Say a bacterial colony is expanding by growth into a new food source. In the simplest picture of roughly circular surface growth, individuals at the expanding front exist in a roughly 1D world; they’re almost certainly the offspring of other individuals living in the same front. Experiments show that","PeriodicalId":91947,"journal":{"name":"Procedia manufacturing","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57525961","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}