bluuebunny/crossref_metadata_2025 huggingface dataset:
Gençlerin Gelecek Beklentilerinin Belirleyicileri
Authors: YÜCEL İbrahim , BUZ Sema
Published: October 2023

Bu araştırmada gençlerin gelecek beklentilerinin çeşitli yönleriyle ortaya konması amaçlanmıştır. Araştırmada nitel yöntem ve fenomenolojik yaklaşım kullanılmıştır. Araştırmanın çalışma grubunu Ankara’daki gençlik merkezlerinden yararlanan 12 genç oluşturmuştur. Araştırmanın verileri araştırmacılar tarafından hazırlanan kişisel bilgi formu ve yarı yapılandırılmış görüşme formu kullanılarak toplanmıştır. Elde edilen veriler Maxqda programı aracılığıyla analiz edilmiştir. Araştırma sonuçlarına göre gençlerin geleceğe bakış açısında ekonomik faktörlerin etkili olduğu ve gelecek kaygısı yaşadıkları tespit edilmiştir. Bununla birlikte, bireysel kapasite ve teknolojik gelişmelerin gençlerin geleceğe yönelik umut beslemesini sağladığı, ulusal ve küresel krizlerin ise umutsuzluk kaynağı olduğu sonucu ortaya çıkmıştır. Araştırmanın sonunda sosyal hizmet perspektifinden önerilere yer verilmiştir.
Educational Game-Based Mathematics Learning Media for Elementary School Children
Authors: Sirumapea Agustinus , Ferawati Ferawati , Saputri Fiqih Hana , Utama Andhika Fajar
Published: October 2023

This study aims to produce and test the feasibility of an educational game for Mathematics using Construct 2 software. This game contains Mathematics subject matter and is used as a learning medium at SDIT Smart Syahid. The research method used in making this Educational game is ADDIE (Analysis – Design- Development – Implementation – Evaluation), where the research stages are in the form of needs analysis, design process, product development, implementation, and evaluation. The analysis phase includes a needs analysis related to the product. The stages in the design process include the design process and making improvements if there are still design discrepancies between the user and the analyst. The product development stage contains manufacturing based on the analysis and design results that have been done before. Next is the implementation stage; at this stage, the programmer develops the design into a program that can be tested. The last step is the evaluation stage and making improvements if there are still design discrepancies between the user and the analyst. From the results of this study, the researcher succeeded in creating a Mathematics educational game.
Principals’ Leadership and Management Perspective on High School Violence: The South African Case Study
Authors: Bolitina Bulelwa Elphrida , Nomtshongwana Thanduxolo Albert , Buka Andrea Mqondiso
Published: October 2023

The paper sought to explore solutions to revolutionary principal leadership practices for the next generation in contemporary African society. Despite the efforts done by the government, schools continue to be confronted with problems of disruptive behaviour by students and some disrespectful people from the society. The study targeted principals of the Libode Sub-district of OR Tambo District using the purposeful sampling technique. Data was qualitatively collected and the analysis was done thematically. The findings of the study revealed that regulations, acts, and rules set by the DoE are outdated and made it difficult for principals to maintain school discipline. The study further revealed that lack of resources, safety and security contribute to poor leadership practices, drug abuse, and safety leading to disruptive behavior (cases). Also, alternatives measure to corporal punishment in managing school discipline could not solve ill-discipline problems. This paper recommends that policy on drug abuse, safety and security should be revised. There should be also rethinking around the issue of better security and a need for a consolidated and coordinated system in schools.

Keywords: Disruptive Behaviour, School Violence and Sexual Harassment
A new record of Upeneus pori (Actinopterygii: Syngnathiformes: Mullidae) from the South China Sea: Integrating morphology and DNA barcoding
Authors: Luo Zhisen , Yi Murong , Gu Sui , Lin Hung-Du , Yan Yunrong
Published: October 2023

This study constitutes the first record of the Por’s goatfish, Upeneus pori Ben-Tuvia et Golani, 1989, from the South China Sea. This fish had formerly only been reported in the western Indian Ocean. Six specimens of U. pori collected from the South China Sea were identified through comparisons of morphology and molecular analysis. Upeneus pori and Upeneus tragula Richardson, 1846 are very similar. The difference is that the former has seven spines in the first dorsal fin, lacks any spots or blotches on its body, and exhibits white or creamy white barbels. The latter has eight spines in the first dorsal fin, exhibits black spots on its body, and displays orange-colored barbels, along with different caudal fin patterns. Pairwise genetic distance computation demonstrated that U. pori exhibits a very low genetic distance from sequences of the other three recorded U. pori species found in the type locality of Israel, Red Sea, as documented in GenBank. These findings provide compelling evidence of the Por’s goatfish’s presence in the South China Sea.
Ten years later: An update on the status of collections of endemic Gulf of Mexico fishes put at risk by the 2010 Oil Spill
Authors: Chakrabarty Prosanta , Sheehy Alec , Clute Xavier , Cruz Shannon , Ballengée Brandon
Published: October 2023

The 2010 Gulf of Mexico Deepwater Horizon was the largest spill in human history that occurred during a 12- week period over ten years ago; however, after more than a decade of post-spill research little definitive remains known about the long-term impacts on the development and distribution of fishes in and around the region of the disaster. Here we examine endemic Gulf of Mexico fish species that may have been most affected by noting their past distributions in the region of the spill and examining data of known collecting events over the last twenty years (ten years prior to the spill, ten years post spill). In addition some observational data that did not result in specimen collections are also examined here. Five years post spill, it was reported that 48 of the Gulf’s endemic fish species had not been collected, with expanded methods we now report that 29 (of the 78 endemic species) have not been reported in collections since 2010 (five of these are only known from observations post-spill). Although there is some cause to celebrate the good news that some previously ‘missing’ species have been found, the lack of information for many species remains a cause for concern.
L’importance d’une perspective organisationnelle dans la gestion du harcèlement au travail : « Ce n’est vraiment pas la peine d’en faire un drame ! »
Authors: Timmermans Marian , Pernet Muriel
Published: October 2023

Le harcèlement au travail affecte de nombreuses personnes ; pourtant, les professionnels qui travaillent en tête-à-tête avec leur clientèle y réfléchissent souvent d’un point de vue individuel. Dans cet article, l’auteur étudie l’importance d’observer le harcèlement au travail d’un point de vue organisationnel et de le voir comme une fonction du scénario organisationnel. Elle suggère de le considérer comme un jeu de groupe où les spectateurs détiennent un rôle important. Elle propose de travailler dans une perspective organisationnelle systémique pour aider à clarifier la nature du jeu. Cette perspective a produit des résultats intéressants dans un programme de lutte contre le harcèlement scolaire.
Le pilotage de la performance globale des établissements éducatifs : des pistes pour faire mieux avec peu
Authors: Dibi Abdessamad
Published: October 2023

Les établissements éducatifs opèrent dans un environnement marqué par l’intensification des pressions subies de toutes parts alors que leurs modes opérationnels demeurent entravés par des rigidités organisationnelles intrinsèques qui émanent parfois d’une gestion approximative. Le renforcement de leur efficacité exige alors l’adoption de principes susceptibles d’atteindre de meilleurs résultats en faisant une large place à l’innovation. C’est dans ce cadre que nous proposons le recours à des innovations managériales de type socio-économique. Les résultats obtenus grâce à cette démarche ont permis, à travers des actions concrètes de transformation des coûts cachés en valeur ajoutée dans un établissement, d’identifier des pistes d’amélioration des performances sociales et économiques de l’organisation.
Une diplomatie au défi de l’Asie-Pacifique (Chine, Corée, Japon)
Authors: Sibre Olivier
Published: October 2023

La diplomatie du Saint-Siège est devenue globale au xx e  siècle parce qu’elle est devenue mondiale. Le Saint-Siège a investi un effort considérable en Asie Pacifique, tant sur le plan missionnaire au sens strict que sur le plan diplomatique et humanitaire à travers ses représentants à Tokyo, à Pékin et à Séoul. Le pontificat de Pie XII a coïncidé avec la guerre du Pacifique et la Guerre froide dans la région. Dans cet article, nous essayons de tracer les grandes lignes d'une longue histoire du Saint-Siège en Chine, en Corée et au Japon, et de mettre en évidence le tournant des années 1930 et 1940.
Le clerc en sursis ?
Authors: Soupa Anne
Published: October 2023

Dans la plupart des confessions religieuses, les femmes restent exclues des charges sacerdotales. Pour combien de temps ? Institution patriarcale au superlatif, l’Église catholique voit désormais son modèle vaciller.
L’éternel retour
Authors: Dupuis-Déri Francis
Published: October 2023

Depuis son émergence, le féminisme génère régulièrement de « nouvelles masculinités », en réaction ou en adhésion. Pour autant, les réflexes perdurent même chez les hommes les plus sensibilisés.
Une pratique égalitaire
Authors: Jacquemart Alban
Published: October 2023

Les réunions entre femmes constituent des piliers des mobilisations féministes. Revenir sur l’histoire de ces pratiques militantes permet de dépasser les idées reçues qui persistent à leur sujet.
Le front de l’eau
Authors: Mallet Loïs
Published: October 2023

Très médiatisée, la lutte contre les méga-bassines dans les Deux-Sèvres a pris cet été un tournant itinérant. L’objectif : obtenir un moratoire sur leur construction et exiger une gestion de l’eau équitable et écologique. Récit d’un chercheur embarqué.
Les deux visages de la finance
Authors: Scialom Laurence
Published: October 2023

Outil du pire comme du meilleur, la finance entretient aujourd’hui le dérèglement climatique. Des réformes et un désinvestissement massif des secteurs carbonés pourraient en faire un levier vers une société soutenable.
La subsidiarité : au-delà du principe, un procédé à adapter aux réalités des conflits modernes
Authors: de Chilly Nicolas
Published: October 2023

La réalité complexe des conflits modernes met la subsidiarité en tension, entre l’inévitable centralisation de certaines décisions dans le contexte politico-stratégique actuel et une nécessaire décentralisation du commandement pour accélérer la décision et prendre l’ascendant sur l’adversaire. Dépasser ce tiraillement exige une vision dynamique des organisations, suffisamment agile pour adapter l’exercice de la subsidiarité aux circonstances, aux moyens et aux enjeux. Cette étude propose des pistes pour retrouver confiance dans la décision individuelle des chefs de tout niveau, dont la responsabilisation doit être accompagnée d’une formation, d’un entraînement et d’une pratique renouvelés.
Transformation numérique de l’administration : la recherche d’efficacité et d’agilité
Authors: Lamatsch Harald
Published: October 2023

La numérisation de l’administration est un levier significatif d’économies en termes de personnel et de coûts de fonctionnement. Nous sommes au cœur d’une situation d’urgence et nous devons développer des idées pour agir. Les conditions-cadres et espaces d’action de la numérisation innovante et le contexte de l’administration publique mènent au constat que le véritable art consiste d’une part, à prendre en compte le besoin politique d’immédiateté et de visibilité, et d’autre part, à attribuer des leviers d’action au sein de l’administration. La première des solutions est de déployer des unités d’innovation qui assurent la capacité de mettre en œuvre ce que le monde privé numérique exploite déjà depuis des décennies.
Les essaims de drones, graal ou chimère ?
Authors: Noizet Thomas
Published: October 2023

Dronisation et intelligence artificielle convergent aujourd’hui, donnant progressivement naissance à ce qu’il est convenu d’appeler des « essaims ». Les récents conflits renforcent l’idée que ces systèmes – y compris les essaims létaux – présentent un intérêt militaire. Ils feront partie demain des capacités amies et ennemies. Celui qui en sera doté disposera d’un avantage certain. Cependant, leur développement implique de consentir à une forme d’autonomie, ce qui suscite de nombreuses questions. Notre pays sera guidé par sa vision de l’éthique d’emploi des essaims et des armes dites « autonomes ». Pour autant, il convient d’avancer de manière résolue dans la voie des essaims, y compris vers les essaims armés.
Livrer la bataille des ressources stratégiques pour gagner la guerre avant la guerre
Authors: Florentin Georges-Antoine
Published: October 2023

Après la prise de conscience du manque de résilience d’un système reposant sur des flux mondialisés, le retour d’une guerre interétatique de haute intensité sur le continent européen pousse à s’interroger sur les ressources qui permettront de l’emporter en cas de conflit. Si la France souhaite gagner la guerre avant la guerre, il lui faut mener la « guerre pour les ressources » dans la phase actuelle de compétition entre puissances, afin de disposer des moyens nécessaires en cas d’affrontement. Pour cela, il est nécessaire de penser la stratégie française d’accès aux matières premières et aux espaces communs, et de demander à la jeunesse de s’engager pour augmenter la résilience de la nation.
Adhésion de la Suède à l’Otan : évolution de sa politique de sécurité et implications stratégiques dans la région de la Baltique
Authors: Norlen Johan
Published: October 2023

L’attaque illégale de la Russie contre l’Ukraine a marqué le plus grand changement dans la politique de sécurité suédoise depuis très longtemps. La Suède, qui a une très longue histoire de non-alignement militaire, a demandé à adhérer à l’Otan et a décidé, dans le même temps, d’augmenter considérablement son budget de défense. L’article abordera l’évolution de la politique étrangère suédoise et les implications géopolitiques pour l’Otan d’un Nord unifié sous le contrôle de l’Alliance. Enfin, les opportunités et les défis découlant de cette adhésion seront traités.
Quelle stratégie pour la France en Afrique ?
Authors: Prod’homme Pierre
Published: October 2023

Posant le besoin d’adaptation de notre posture devant le constat d’une Afrique qui change, le président de la République Emmanuel Macron a acté la réorientation stratégique dans son discours du 27 février 2023. Le cap fixé, fondé sur une nouvelle approche partenariale, constitue une opportunité de sortir des cordes dans lesquelles nous nous sommes laissé acculer et de reprendre l’initiative. Encore faut-il faire preuve de lucidité dans le diagnostic stratégique afin d’appliquer le bon traitement et définir les conditions du « succès » via des principes clairs, d’objectifs réalistes ainsi que d’écueils à éviter qui prendront chair par l’intermédiaire de voies et moyens ancrés dans le réel.
« L’Ancien Régime des graffitis »
Authors: Cuvelier Laurent
Published: October 2023

Cet article ouvre sur un double chantier méthodologique et historiographique : retrouver la trace des graffitis de l’époque moderne passe notamment par une histoire visuelle de la ville. De plus, l’association contemporaine entre graffitis et vandalisme prend sens aux 17 e -18 e siècles. Ces dessins et inscriptions sont alors au cœur d’une synthèse liant condamnation morale des mœurs citadines et préservation de certains espaces touristiques. Enfin, si les graffitis ont souvent été placés au second plan de l’histoire des mobilisations politiques par rapport aux imprimés ou aux chansons, ils constituent cependant une forme d’expression et un outil de contestation dont la perception policière évolue en France après 1789, passant du crime de lèse-majesté au délit d’opinion.
« Les Gilets jaunes triompheront »
Authors: Artières Philippe
Published: October 2023

Le mouvement des Gilets jaunes, entre la fin 2018 et le début 2020, a été le lieu de pratiques d’écritures de la contestation multiples dont aucune n’est véritablement inédite dans l’histoire des mouvements sociaux en France. La spécificité de cet usage de l’écrit, en mobilisant les outils de l’anthropologie de l’écriture, tient à la chaine d’écriture qui relie les banderoles sur les ronds-points occupés, les inscriptions sur les gilets de sécurité des protestataires et les graffiti lors des manifestations. L’analyse montre en particulier l’importance d’une inscription le 1 er décembre 2018 sur l’Arc de triomphe à Paris comme principe de légitimation de discours individuels minorés et comme programme d’écriture collectif.
Arrhythmia Detection and Classification on Cardiac Sensed Signals Using Deep Learning Techniques
Authors: Maurya Jay Prakash , Manoria Manish , Joshi Sunil
Published: October 2023

Arrhythmia is a general type of cardiac disease in persons between 30-40 years of age. Cardiac system in human body generates electrical pulses that can be captured and plotted through electrical system called ECG. Computer-aided diagnosis system (CADS) is a good approach to help the healthcare field for early, regular, and accurate diagnosis and treatment plan during critical care conditions. Deep learning-based CADS can helps in critical condition for more quick diagnosis and treatment in countries where doctor ratio is comparatively low. With the help of machine learning (ML) algorithm, intervariable relationships may be used for prediction. However, machine learning algorithms are also limited due to its datasets availability, established framework, and clinician unfamiliarity. This chapter aims to provide an idea of arrhythmia and CADS approach using cascaded deep learning model of CNN, LSTM, GRU, and RNN. The chapter focuses on techniques used in past years, comparative studies, and direction of research as future improvements in respective fields.
Smart Drugs in Cognitive Disorders
Authors: Phogat Jatin , Bali Alka , Kapoor Nishika
Published: October 2023

More than 65% of the elderly population globally suffers from dementia. The term “smart drug” refers to any drug substance that positively impacts mental skills. Nootropics are agents that are used for boosting the performance of the brain and to increase one's concentration. These are also called cognitive enhancers as these can enhance memory, creativity, awareness, and attention. Natural sources, as well as synthetic approaches, both, are being employed by researchers worldwide for developing smart drugs. Smart drugs are intended to enhance academic, social, as well as career performance. These drugs work by boosting the oxygen supply and nutrition to the brain and are useful for treating various neurodegenerative disorders. Several mechanistic pharmacological approaches have been explored for the development of smart drugs and enhancement of brain activity, the most prominent ones being glutamatergic, dopaminergic, serotonergic, and cholinergic pathways. This chapter reviews the various approaches for developing synthetic smart drugs and their applications and limitations.
Hospital Waste Management Using Internet of Things and Deep Learning
Authors: Ugandar R. E. , Rahamathunnisa U. , Sajithra S. , Christiana M. Beulah Viji , Palai Basanta Kumar , Boopathi Sampath
Published: October 2023

Hospital waste management is crucial for healthcare operations, ensuring safe disposal and handling of waste types. The integration of IoT and deep learning technologies offers a promising solution to address waste volumes and environmental concerns. This chapter presents an advanced research overview on hospital waste management using IoT and DL, exploring its potential benefits and applications. IoT-DL integration enables real-time monitoring of waste fill levels, temperature, and other parameters, while advanced DL techniques improve waste collection efficiency, segregation accuracy, and data-driven decision-making for optimized waste management practices. The chapter discusses challenges, benefits, challenges, and considerations in IoT implementation, waste sorting techniques, and ethical and environmental aspects, including sustainability and circular economy principles.
Bioremediation of Pharma Pollutants Using Synthetic Systems
Authors: Waghmode Meghmala S. , Gunjal Aparna Baban , Gadekar Manisha , Mali Dipali Deepak
Published: October 2023

The pharmaceutical industry is responsible for the environmental pollution imposed by drugs, heavy metals, and surfactants. In-situ remediation of pharma pollutants with the cell-based system has some limitations like sensing of contaminants, efficacy, cost, concentration of pollutants, toxicity level, etc. Synthetic biology is important for gene mining, enzymes discovery, and biodegradation pathway of pollutants. The chapter is based on the synthetic systems for remediation of the pharma pollutants.
CF Reinforced Thermoplastic Hybrid Process Proposal for the Optimization of Sandwich Panels Stiffness and Processability
Authors: Rodríguez-Mondéjar Carlos , Rodríguez-Prieto Alvaro , Camacho Ana Maria
Published: October 2023

The development of composite materials has meant, over the last few decades, a challenge for research in relation to the search for new ways of manufacturing. Currently, a wide variety of materials and processes have a high degree of development and industrial applications, but the potential for improvement in this area promotes the search for new systems that allow obtaining products with better mechanical characteristics and better manufacturability. Within this framework of the development of processes and applications, the following combination of manufacturing technologies is proposed: thermoforming and overmolding of carbon fiber reinforced thermoplastics with continuous and short fibers respectively. The aim of this work is to provide a hybrid technology to manufacture sandwich panels whose stiffening core geometry can be highly optimized based on the load requirements considered in the design of the product of interest. The proposed process consists of the prior shaping by thermoforming process of a continuous fiber-reinforced thermoplastic laminate on one of the surfaces of the manufacturing mold that will later be used for injection of the core structure with a counter-mold adapted for this purpose. The injection of the short fiber reinforced thermoplastic will be carried out in such a way that one of the surfaces of the resulting cavity is directly in contact with the previously formed laminate, giving rise to an overmolding. After this operation, a closing laminate will be formed that will give the panel the desired resistance. A detailed analysis of the different stages of this process is necessary, especially with regard to the processing parameters (e.g. injection temperature, pressure, polymer velocity, and interface temperature), orientation of the fiber resulting from the injection process, the adhesion of the polymer between stages, and the geometric limitations of considered sub-processes. The analysis is performed using a finite element method (FEM) software and analytical approaches.
Design of a Test Part for Verification and Validation of a Three Linear Axes Machine Tool
Authors: Jiménez Sergio Aguado , Lorente Laura , Albajez José Antonio , Velázquez Jesús , Mazo Jorge Santolaria
Published: October 2023

On traditional manufacturing systems such as machine tools (MTs), the increase on their operational capacity goes hand in hand with the improvement of its efficiency and accuracy. To do that, there are two types of verification methods, direct and indirect methods. The main aim of this job is to develop a test part to machine that allows determine the influence of the geometric errors of a three linear axes MT using volumetric and geometric methods. When the test part is machined, all axes of the machine are moved simultaneously. So, the difference between machined and test part design are, among others, the results of MT geometric errors. These errors can be reduced using volumetric verification techniques and MT compensation. Moreover, a proper test part design provides a work piece than can be used as a reference artefact for MT calibration. Nominal data of the test part can be obtained using a coordinate measurement machine. So, if the MT measures the machined test part using a probe, the difference between real and nominal coordinates could be used to obtain MT geometric errors. Therefore, the test part has to be designed to allow an easy data capture of the MT; taking into consideration the different kinematic models used to improve its accuracy. The new test part developed consist of a rectangular block with grooves and battlements on its external faces and an internal pyramidal structure. In addition, a series of conical holes are strategically located along the surface to improve data capture and errors identification. Synthetic tests show that this test-part design provides good results using volumetric and geometric techniques.
Weld Joint Reconstruction and Classification Algorithm for Trajectory Generation in Robotic Welding
Authors: Curiel David , Veiga Fernando , Suárez Alfredo , Villanueva Pedro , Aldalur Eider
Published: October 2023

Automation of welding with robotic arms has become an inevitable trend in modern manufacturing technologies. This process can be automated by using a "click and go" in which the robot will weld a line where the spot is described or by using an in-line tracking algorithm in which the robot will choose the spot where to weld the line in each layer. This paper presents a simple methodology for the reconstruction of the weld joint and the classification of the joint geometry to serve as a first step to the automatic determination of the robot trajectory. The weld joint has been reconstructed using a laser profilometer placed as a tool on the robot. Spurious data has been removed by signal processing. The joint has been reconstructed three-dimensionally. The classification of the joint profiles was generated using an algorithm based on signal processing and artificial intelligence. This algorithm has been tested for the classification of V-joints (bevel-bevel) and single bevel joints.
Identification of Criteria for the Protection and Enhancement of Railway Industrial Heritage Assets through the Analysis of Two Examples on the Border between Spain and Portugal
Authors: de Grado Jose I. , Claver Juan , Sebastián Miguel Ángel
Published: October 2023

Spain and Portugal share a common track gauge, different from the European standard gauge, and they have come to have 5 rail connections of which only 3 are currently active. On the two disused connections two different programs have developed for their respective protection, conservation, and valuation in the service of society. In the Spanish province of Salamanca, the route from the railway station of Boadilla-Fuente de San Esteban to the Portuguese border. This route has been recognized as a Bien de Interés Cultural (BIC) since 2000 and has been preserved including all the infrastructure and a good part of the railway superstructure. The Camino de Hierro program, at the final section, is a route of 17 km, conditioned for walking, crossing the Natural Park of Arribes del Duero. The program is managed by public initiative of the Diputación de Salamanca. On the other hand, we have the railway connection from Caceres to Valencia de Alcantara (last Spanish town) that then crosses into Portugal through Marvão-Beirã (first Portuguese station) to Torre das Vargens, where it connects with the route currently in use from Badajoz, through Elvas to main station of Entroncamento. Between the first two Portuguese stations, a private initiative (Rail Bike Marvão) has launched a program to make this 15 km route traversable on pedal-operated platforms on the railway and crossing the Serra de São Mamede Natural Park. This paper analyses both initiatives, identifying their strengths and weaknesses and the strategies employed as examples of good reference practices for similar initiatives, in order to identify key aspects which will be part of the criteria that the authors want to define as the initial phase of a methodology for the application of decision-making techniques in the management of these kind of assets.
Using PETG/rPET Blends in Fused Particle Fabrication: Analysis of Feasibility and Mechanical Behaviour
Authors: Fernández Pelayo , Marqués Raúl , Beltrán Natalia , Puerto Blas , Blanco David
Published: October 2023

Additive Manufacturing (AM) production of plastic parts has experienced a continuous increase during the past decades. Simultaneously, advanced societies have become deeply concerned about the use of plastics and their impact on natural environments. As a result, there is a growing interest in recycled plastic as a feedstock material in additive manufacturing machines. However, the commercialization of recycled plastic filament introduces additional production and distribution steps. An alternative approach would avoid these steps by mixing recycled particles (obtained from local waste) with brand-new particles and using the resultant blend with Fused Particle Fabrication (FPF) machines, but some alimentary plastics, like Polyethylene Terephthalate (PET) have printability issues that hamper their direct use in AM. Present work analyses the feasibility of extruding blends composed of Polyethylene Terephthalate Glycol (PETG) spherical pellets and recycled Polyethylene Terephthalate (rPET) flakes so that local prosumers could give a second use to their own wasted water bottles. Additionally, tensile, and flexural specimens were analyzed for combinations of different rPET particle sizes and PETG/rPET blends (100%PETG, 30%rPET/70%PETG, 50%rPET/50%PETG, and 70%rPET/30%PETG). The experimental program included relaxation tests from which the relaxation modulus, E(t), was obtained. The results showed that the addition of PETG combined with a modification that insufflates pressurized air into the pellets inlet would permit to print blends up to a 70% rPET. It has also been found that an increase in the percentage of rPET causes a slight increase in the relaxation modulus of the test specimen. Finally, the viscoelasticity ratio remains nearly constant among the different blends whereas particle size has been found to have an influence on the results.
Numerical Process Design for the Production of a Load-Adapted Hybrid Bearing Bushing
Authors: Uhe Johanna , Wester Hendrik , Behrens Bernd-Arno
Published: October 2023

Due to increasing product requirements regarding lightweight, functional integration and resource efficiency, research into and use of hybrid parts are steadily increasing. Tailored Forming provides an innovative process chain for manufacturing hybrid parts by using pre-joined semi-finished products. In addition to the potentials, however, challenges also result in the production of hybrid components. In particular, the material combination of steel and aluminium is demanding due to strongly differing physical properties. An inhomogeneous temperature distribution within the pre-joined semi-finished part can be used to equalize flow properties during the forming process. However, processes are sensitive to temperature deviations resulting in critical stresses and failure of the final part. This study focuses on a process design of a hybrid bearing bushing consisting of the aluminium alloy EN-AW-6082 and the steel 100Cr6 using numerical simulation. First, a closed-die forging process is analysed regarding sensitivity to process fluctuations resulting in deviations in temperature distribution. To increase process stability, a new hollow forward-impact extrusion process is numerically designed and investigated regarding its potential to reduce critical stresses and thus the risk of part failure. Furthermore, a numerical model of inductive heating is used for the consideration of inhomogeneous temperature fields. Finally, hybrid bearing bushings are produced using closed-die forging and hollow-forward extrusion to evaluate numerical results.
Experimental Investigation on Surface Characteristics of Long Thickness Parts of CFRP during Abrasive Water Jet Machining Process
Authors: Bañón-García Fermín , Salguero Gómez Jorge , Bienvenido Rafael , Vazquez Martinez Juan Manuel
Published: October 2023

The use of advanced materials in new fields of applications is usually related with specific properties and great advantages. However, it may become an important technological challenge for the manufacturing and joining of these materials. Carbon Fiber Reinforced Plastic (CFRP) is widely used in aerospace or automotive industry, but currently is starting to be used as structural component in the building industry. In contrast to the thin parts developed for aircraft. the elements for construction are characterized by high thicknesses. This fact increases the abrasive effect of carbon fibre on cutting tools when it is machined by conventional processes. For this reason, non-conventional technologies. as Abrasive Water Jet Machining (AWJM), could be a suitable technology for this purpose. An operation of great interest for these materials is drilling. The industry demands the drilling of a wide range of increasingly large diameters. This, in combination with large thicknesses in CFRP, makes the machining process more difficult. Technologies such as orbital drilling are limited by the range of diameters that can be obtained and the abrasive wear between the material and the cutting-tool. Therefore, the use of abrasive waterjet cutting is proposed as an alternative technology capable of machining diameters in a wide range. One of the main limitations for the use of AWJM on large thickness parts of CFRP comes from the surface finish of the machined surfaces. where high values of roughness can be found. In this research, the effects of water jet cutting parameters have been evaluated for the machining of 17 mm thickness CFRP specimens. By variations on the traverse speed. abrasive mass flow rate and hydraulic pressure. differences in the performance and micro-geometrical characteristics of the machined surfaces were obtained, allowing to identify most significant affecting parameters of the process.
Manufacturing of Novel Cork-STF Composites Designed for Impact Energy Absorption
Authors: Sousa Guilherme J. A. , Fernandes Fábio A.O. , Rocha Ana R. S. , Serra Gabriel F. , de Sousa Ricardo J. Alves
Published: October 2023

Shear thickening fluids (STF) viscosity significantly increases when subjected to an external dynamic load. Recent advances show their potential for engineering applications, such as developing shock absorbers and impact energy-absorbing structures. There is a search for sustainable materials for several applications due to the critical need to replace nonrenewable raw materials. Cork is a sustainable material reported to be an excellent alternative to synthetic energy absorbers thanks to its cellular microstructure and cell wall composition. This work explores the development of cork-STF composites designed for impact energy mitigation. The cork-STF composites were manufactured by compression moulding, exploring different compositions of both materials. Additionally, the manufactured compounds were characterized by submitting samples to impacts. The results made it possible to conclude that deagglomeration occurs for STF concentrations higher than 20%. On the other hand, good results were achieved with compounds that have less than 20% of STF in their composition and can withstand impact loading. Therefore, the energy absorption of white cork agglomerates decreases with STF. Nevertheless, the agglomeration was successful, and this design can be adapted for other specific purposes, applications, or even strain rates than the ones explored in this work.
Full Automation of a Manual Inspection Unit for Industrial Borescopy
Authors: Gil-Cuadrado Alberto , Martínez-Gutiérrez Alberto , Díez-González Javier , Verde Paula , Ferrero-Guillén Rubén , Perez Hilde
Published: October 2023

The digitization of processes in the context of Smart Manufacturing enables the control and monitoring of production processes. Visual inspection of parts is a process where the surface finish of machined parts is evaluated. For this purpose, manual inspection units have been traditionally used to evaluate the validity of the parts. This manual inspection process requires the operator to position the lens to obtain the images, which supposes an inefficient and non-repeatable process producing a considerable waste of production time. In order to design a more competitive process in the context of Smart Manufacturing, we fully automate in this paper an industrial borescopy unit by implementing closed-loop stepper motors, sensors, and microcontrollers. In addition, a web server has been programmed where operators monitor and upload ISO codes depending on the inspected part. This web server is connected to the microcontroller and the borescope positioning camera for automatic imaging. Therefore, the visual part inspection unit has been digitized and provided with connectivity and intelligence as the cyber physical system of the Smart Manufacturing.
Implementation of a Test Plan Ontology for Incremental Sheet Metal Forming Made with Models for Manufacturing (MfM) Methodology
Authors: Morales-Palma Domingo , Mas Fernando , Arista Rebeca , Oliva Manuel , Vallellano Carpoforo
Published: October 2023

Models for Manufacturing (MfM) is a methodology currently under development with a novel approach to applying Ontology-Based Engineering concepts to manufacturing. MfM is based in a 3-Layer Model (3LM) framework: a Data layer that collects all the information, e.g. in databases, an Ontology layer for ontological deﬁnition containing the domain knowledge, and a Service layer comprising all necessary software services. The Ontology layer is the core of the 3LM framework and is made up of 4 models: Scope, Data, Behaviour, and Semantic models. The 3LM framework is supported by user-friendly modelling tools and guarantees independence between the 3 layers. This work aims to evaluate the MfM methodology through the development of a real use case based on previous work by the authors: an experimental test plan to study sheet metal formability in hole-flanging operations by Single-Point Incremental Forming (SPIF). The test plan includes the definition of the main geometrical parameters of the specimens, the generation of the forming tool paths and G-code for a CNC machine, the evaluation of the manufactured parts and the analysis of the material formability. The paper presents the definition of the Ontology layer for the developed use case using various graphical modelling tools and a simple implementation of Data and Service layers as well as the interfaces between the 3 layers. The conclusions of the work highlight the strengths and weaknesses of the application developed and point out the main lines of future development of the MfM methodology.
Digital Twin Development and Validation for a Tapered Roller Bearing Multi-Stage Production Line
Authors: Domínguez Javier , Esteban Alvaro , Romeo José Antonio , Cebrián Fernando , Santo Domingo Sergio , Aguilar Martín Juan José
Published: October 2023

The objective of this work is to develop and validate a Digital Twin (DT) for a multistage production line of tapered roller bearings. The manufacturing process consists of ring machining and component assembly, including intensive quality controls. This work proposes the integration of machine learning models associated with the manufacture of the double outer ring and the two inner rings in the DT. The models are trained with real data, so that the DT can predict the behavior of the production process under changing conditions of ongoing processes, machines or materials, and optimal operating conditions can be predicted. The DT has been developed and integrated with the aim of guiding production by proposing optimal machine configurations. To this end, different stations have been modeled and integrated into the DT as independent modules: grinding machines, inner and outer rings pairing module, and a module for calculating the optimal family of rings to be ground. After integrating the DT in the line, results show not only a raise in the line efficiency but also a decrease in the overall scrap ratio.
An Approach to Zero-Failures Maintenance Using Industry 4.0 in Network Connected Multistage Industrial Machines
Authors: Álvarez García Francisco Javier , López Pérez Óscar , González González Alfonso , Rodríguez Salgado David
Published: October 2023

The industrial manufacturing systems are increasing in complexity to market changes. One of the best challenges of this complex systems is reach the schedule production baches without unexpected failures, looking for the zero defects. The presence of Multistage Machines (MSM) at industrial manufacturing systems allow to produce big batches in very short times. Nevertheless, these types of machines normally are manufactured as an ad hoc machine and have not maintenance strategies tested for preventive or predictive actions. Also, if a component of this machine fails, the entire machine fails, causing the loss of the production batch. Recent publications have developed local preventive and predictive maintenance strategies for industrial multistage machines, as an individual machines with local work conditions in different places. Nevertheless, the accumulated knowledge of a MSM cannot be used as relevant information to improve maintenance actions in other MSM. This research develops and proposes a network system, called Master Maintenance Management (MMM) to establish a continuous connection with all MSM, working as a datalogger who collects all relevant information for all MSM and suggest maintenance warning predictive and preventive warnings for machines and use them for preventive actions in the rest of each MSM working at the same conditions. So, the capability of one machine for take a local predictive action is performed by the MMM to take a preventive action in the other machines connected to the same network. This approach has been developed with thermoforming multistage machines, who have local preventive maintenance strategy based on individual maintenance times and predictive maintenance strategy based on some distributed sensors in the machine and a behaviour algorithm, called Digital Behaviour Twin (DBT). The most relevant benefits of this approach are the limitation of unexpected failures in the connected machines by using accumulated information of other MSM, the change of the predictive actions to preventive actions, and the machine perform by design changes suggested with all the database collected.
Simulation-Assisted Analysis of Sand Casting Distribution Systems for Teaching Purposes
Authors: Sambruno Alejandro , Márquez Pablo , Bañón-García Fermín , Puerta-Morales Francisco Javier , Gómez-Parra Álvaro
Published: October 2023

In Engineering Schools, labs for teaching forming processes by means of material conservation methods are generally equipped with the appropriate equipment and tools to exemplify the theory received in class. However, the use of simulation techniques to complement the formation is not usually widely extended, since their learning is not usually trivial.One of the material conservation forming processes is sand casting. This process is of great educational significance, since the theory that defines it sets the basis for understanding other related moulding processes. In this context, the use of simulations of the moulding process allows the visualization of practical examples, helping to explain more clearly the theoretical information explained in class.Therefore, in this research a simulation assisted analysis has been developed using the Inspire Cast by Altair software, of teaching parts made in sand casting. First of all, students have been shown by means of simulations, the defects that can be originated in a part manufactured by sand casting. The study has been carried out by redesigning the risers involved in the distribution system of the process, by means of the Chvorinov's rule.Finally, a series of conclusions have been achieved, among which the following one stands out: if the functional performance of the part manufactured by sand casting is to be taken into account, the cooling modulus criterion must be selected for the design of the riser. Although, in principle, the material required for moulding is much larger, the defects generated in the part will be considerably reduced.
Influence of Impact Speed on the Quality of Riveted Lap Joints of Composite/Metal Stacks
Authors: Ojeda Ibai , El Moussaoui Bilal , Iriondo Edurne , Girot Mata Franck Andres
Published: October 2023

Riveting is the most important method for joining two sheets of different materials. In order to promote electromagnetic pulse riveting (EMR), the influence of the impact velocity will be studied in this paper in order to correctly model the electromagnetic field of the riveting process. There are many parameters associated to the riveting process, however, the interference fit is considered as the most important criterion to measure the riveting quality, which consequently will be associated to the impact velocity, being this the most important parameter. The use of the washer will be studied to guarantee the optimal flow of the material and to restrict the expansion of the rivet shaft, thus minimizing damage to the composite material. The interference generated between the rivet shaft and the hole of the sheets and the flow of the material will be developed by finite elements which will later be validated by means of experimental tests analyzing its final microstructure. Finally, the relationship between the impact velocity on the rivet head will be directly related to the distribution of the interference generated in the deformation, verifying that the impact velocity.
On the Manufacturing of a Cranial PEEK Implant Using SPIF
Authors: Rosa-Sainz Ana , Ferrer Ines , Garcia-Romeu Maria Luisa , Silva Maria Beatriz , Centeno Báez Gabriel
Published: October 2023

This article presents an experimental investigation of biocompatible Polyether ether ketone (PEEK) polymeric sheet deformed using Single Point Incremental Forming (SPIF) at room temperature, with the objective of manufacturing a cranial medical implant. The investigation was performed in terms of formability and failure within the principal strains space, being the material Forming Limit Diagram (FLD) assessed by means of Nakajima tests. This material characterization allowed to obtain the formability limits at necking and at fracture of PEEK polymeric material. In addition, an experimental work plan in SPIF was performed in terms of spifability (or formability in SPIF) with the aim of determining the effect of the main process parameters on the spifability, modes of failure, and temperature, among others. As a result, an optimum set of parameters along with the established methodology were used for manufacturing a cranial medical implant made of this high-performance and biocompatible polymeric material. The work primarily shows the feasibility of manufacturing PEEK medical prostheses and implants using SPIF.