1,720,970 research outputs found
Future Trends and Challenges in Super-finishing Processes
No full textThis chapter focuses on the future trends and challenges in super-finishing processes after metal Additive Manufacturing (AM) processes. With the increasing use of metal AM techniques in various industries, there is a growing need for efficient and effective post-processing techniques to improve the quality and functionality of these products. The chapter highlights the microstructural features and mechanical properties of metal AM products that influence the selection of super-finishing techniques. It also discusses the different super-finishing techniques that can be employed to enhance the surface finish of AM products, such as abrasive machining, sanding, mass finishing, coating, burnishing, bonding and electrochemical polishing. The chapter further explores the challenges faced by manufacturers in achieving the desired surface finish and suggests possible solutions to overcome them. Finally, the chapter proposes several future research directions to enhance the effectiveness of super-finishing processes after metal AM
Advanced Characteristics of Materials Used in Additive Manufacturing
No full textAdditive Manufacturing (AM) has revolutionized the manufacturing industry by enabling the creation of complex and customized parts. The main success of this AM technology can be attributed to the reduction of waste and environmental impact, as well as allowing for the creation of lighter-weight structures. In fact, when these lighter structures are applied to aerospace or automotive applications, they lead to saving fuel and related environmental (and financial) benefits. Unlike AM technology, traditional manufacturing methods often produce large amounts of waste and require significant amounts of energy. AM also allows for the replacement of parts that may otherwise be impossible to replace, meaning that machines can be repaired rather than scrapped. Anyway, the success of AM largely also depends on the quality and characteristics of the materials used. The aim of this chapter is to provide a comprehensive overview of the state-of-the-art research in advanced materials used in AM and highlight their potential for future applications
Advancements in Metal Processing Additive Technologies: Selective Laser Melting (SLM)
No full textNowadays, the use of metal processing additive technologies is a rapidly growing field in the manufacturing industry. These technologies, such as metal 3D printing (also known as additive manufacturing) and laser cladding, allow for the production of complex geometries and intricate designs that would be impossible with traditional manufacturing methods. They also offer the ability to create parts with customized properties, such as improved strength, wear resistance, and corrosion resistance. In other words, these technologies have the potential to revolutionize the way we design and produce products, reducing costs and increasing efficiency to improve product quality and functionality. One of the significant advantages of these metal processing additive technologies is a reduction in waste and environmental impact. However, there are also some challenges associated with these technologies. One of the main challenges is the cost of equipment and materials, which can be prohibitively expensive for small businesses and individuals. Additionally, the quality of parts produced with these technologies can be affected by factors such as printing speed, temperature, and post-processing methods. This review article aims to contribute to a deep understanding of the processing, properties, and applications of ferrous and non-ferrous alloys in the context of SLM to assist readers in obtaining high-quality AM components. Simultaneously, it emphasizes the importance of further research, optimization, and cost-effective approaches to promote the broader adoption of SLM technology in the industry
Overview of Mini-screws in Orthodontics
No full textTemporary anchoring devices (TADs) also known as mini-screws represent today an alternative method to improve orthodontic mechanisms. In particular, these mini-screws are used as ‘anchors’ to facilitate the straightening of the teeth and the closing of the interdental spaces, especially when the application of force could cause an unwanted movement of some teeth. However, a crucial aspect related to the use of these devices is the possibility of breakage during their operational life as well as during positioning and/or extraction. The existence of a fragment of the mini-screw within the jaw not only poses a potential risk of inflammation but also necessitates supplementary interventions to extract the compromised components. Additionally, the materials used may contribute to cytotoxicity. To address concerns related to mini-screw breakage and potential cellular damage, researchers need to investigate two key areas: the resistance behaviour of mini-screws and how their microstructure affects performance during treatment. By understanding these factors, you can choose more reliable and effective mini-screws, ultimately improving patient safety and treatment success. This article provides an overview of mini-screws, presenting and examining the development, advantages and disadvantages of mini-screw implants in the context of temporary skeletal anchorage for orthodontic applications. Furthermore, the paper analyzes the microstructural and mechanical properties of such mini-implants
Caratterizzazione microstrutturale e meccanica di rivestimenti in lega AA 2024 ottenuti mediante Electrospark Deposition
No full textIn questo studio sono stati caratterizzati rivestimenti in lega d’alluminio AA2024 realizzati su substrato omologo mediante ElectroSpark Deposition (ESD). L’ESD è un processo di microsaldatura ad arco pulsato che utilizza impulsi elettrici di breve durata, generati dalla scarica di un condensatore, per trasferire il materiale di un elettrodo mobile ad un substrato metallico.
I rivestimenti prodotti, analizzati con indagini in microscopia ottica ed elettronica a scansione, sono di tipo strato su strato, componendosi di diversi strati sovrapposti. All’interno di ciascuno strato deposto la microstruttura è risultata abbastanza fine a causa delle elevate velocità di raffreddamento coinvolte nel processo.
La durezza media dei rivestimenti non cambia in maniera significativa al variare dei parametri di processo considerati. I rivestimenti presentano difettosità quali vuoti e micro-cricche perpendicolari o parallele all’interfaccia con il substrato. Anche il substrato è caratterizzato dalla presenza di micro-cricche all’interfaccia. All’aumentare dell’energia di scarica si è osservata una riduzione delle difettosità all’interno del coating e un aumento della lunghezza media delle micro-cricche nel substrato
A full-field DIC analysis of the mechanical-deformation behavior of polyethylene terephthalate glycol (PET-G) aligners
No full textObjectives: The aim was to investigate the full-field mechanical-deformation behavior of clear aligners made by polyethylene terephthalate glycol (PET-G) subjected to cyclic compression tests.Methods: Digital Image Correlation (DIC) (Chu et al., 1985; Schreier et al., 2009), a contactless full-field measurement technique, and Optical Microscope (OM) analysis were applied to study two PET-G aligners thermoformed from discs of a thickness of 0.75 mm and 0.88 mm. The clear aligners were placed on dental shape resin casts and were subjected to cyclic compression up to 13000 load cycles from 0 to 50 N at room temperature. The chosen number of load cycles simulates the average load history to which an aligner is subjected for one week. Local displacements and strains were measured for each test at 2, 6, 10, 20, 1000, 5000 and 13000 loading cycles.Results: Both aligners showed greater displacements in the early stages of loading, more pronounced for the 0.88 mm one. Local displacement and strain maps are derived both along the load direction and to the transverse one (never done from other researchers). Load-displacement cyclic curves allowed to evaluate the evolution of the stored energy and the stiffness during the test. The OM analyses showed significant morphological variations on the aligners' surface, such as wear and tear, high depressions and cracks, especially for the 0.75 mm specimen.Significance: Full-field analysis allowed to understand the mechanical behavior of device with complex geometry and complex load distribution, like invisible aligners. The knowledge of the stiffness and the direction of the total displacement helps the orthodontist to implement the best strategy to improve the patient's comfort and the treatment time
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
