bluuebunny/crossref_metadata_2025 huggingface dataset:
Pour un nouvel enseignement de la philosophie. Retour sur La philosophie des professeurs de François Châtelet
Authors: Périn Nathalie
Published: June 2019

Faire retour sur La philosophie des professeurs de François Châtelet, c’est se pencher sur un ouvrage qui posait en son temps (1970) une question que rencontreraient, quelques années plus tard, J. Derrida et le Greph, de la place et de la fonction de l’enseignement de la philosophie dans l’institution éducative française. F. Châtelet apparaît ainsi comme un penseur original de la mise en question de l’institutionnalisation de la philosophie. Critique qui ne se déliera pas (et dans l’œuvre même du philosophe) d’une défense renouvelée de cet enseignement et, plus largement, de la transmission philosophique. Singularité de cet ouvrage qui, pour s’inscrire dans l’héritage critique de penseurs tels que P. Nizan, G. Politzer ou J.-F. Revel, ne voudra pas faire siennes la déploration ou la réaction, mais cherchera les voies problématiques d’une véritable défense et affirmation de la philosophie au sein des établissements d’enseignement. Désidéologiser la philosophie telle qu’elle se présente à travers les programmes et les manuels qui en sont les vecteurs, participera d’une défense re-posée de ce genre de pensée enseigné. La philosophie ne formerait plus aux opinions communes, ne serait plus l’arôme spirituel prenant la place de la religion dans la formation étatique du citoyen. Mais, en se prenant comme objet même de sa propre critique, chercherait plus que jamais à nuire à la bêtise.
Positivisme et antipositivisme dans la Réforme universitaire latino-américaine : José Ingenieros et José Vasconcelos
Authors: Díaz Maldonado Rodrigo
Published: June 2019

Cet essai aborde la relation entre le positivisme d’Ingenieros et la Réforme universitaire engagée à Córdoba en 1918. Pour ce faire, une première partie analyse quelques-uns des principaux écrits d’Ingenieros pour les confronter avec le célèbre Manifiesto liminar qui synthétise les idéaux des jeunes réformistes. Le fil conducteur de l’analyse est l’idée de médiocrité, l’un des piliers de la métaphysique d’Ingenieros et élément clé du Manifiesto . La seconde partie se penche sur la Réforme universitaire mexicaine du début du XX e  siècle, notamment à travers l’antipositivisme de son principal leader intellectuel, José Vasconcelos. Cela vise, enfin, à appréhender les principales ruptures et continuités entre ces deux auteurs.
Le libertinage érudit et la formation de l’homme : le caractère paradoxal de François de La Mothe Le Vayer
Authors: Dupuy Nathanaëlle
Published: June 2019

François de La Mothe Le Vayer, libertin érudit et philosophe du XVII e  siècle fut précepteur de Louis XIV. La lecture attentive des œuvres de Le Vayer fait apparaître, derrière la grande culture des anciens, une pensée critique qui n’est pas dénuée de sens pour notre actualité. Dans un premier temps, par la mise en place du “gouvernement économique” qui est le propre du gouvernement à l’antique, nous allons repérer dans quelle mesure François de La Mothe Le Vayer fait émerger une forme de despotisme éclairé, une gouvernementalité sécularisée au niveau politique, en engageant la séparation du gouvernement pastoral et du pouvoir royal. Dans un second temps, la conception libertine de l’éducation pose une rupture : l’éducation comme émancipation. Par la mise en pratique de l’exercice de la formation de soi-même, notre libertin met en exergue une autre vision de la formation de soi détachée des formes institutionnelles et de la conversion éducative.
Subperiosteal Hematoma of the Orbit: A Variety of Presentations
Authors: Meltzer Daniel Eric , Mirbagheri Saeedeh , Aygun Nafi
Published: June 2019

Subperiosteal hematoma of the orbit is an uncommon radiologic finding. Most typically, the hemorrhage is in the superior aspect of the orbit, however, location within the orbit may vary. Subperiosteal hematoma of the orbit may be associated with trauma. Nontraumatic etiology has also been well documented. We present a series of three cases, to illustrate typical and atypical radiologic findings of subperiosteal hematoma of the orbit, both traumatic and nontraumatic. Review of the pertinent radiologic literature and its relation to the cases presented here is also provided.
La dignidad humana como principio biojurídico y como estándar moral de la relación médico-paciente
Authors: Andorno Roberto
Published: June 2019

El artículo destaca la importancia de distinguir entre dos roles diversos que la noción de dignidad humana juega en bioética: uno, como principio de orden jurídico-político, y otro, como estándar moral del trato debido al paciente. Cuando la dignidad es entendida en el primer sentido, nos encontramos con un concepto muy general, que cumple un rol fundacional y de orientación de las normas relacionadas con las prácticas biomédicas. En cambio, cuando es utilizada en el segundo sentido, intenta captar la exigencia moral de tratar siempre al paciente como “persona”, es decir, con el mayor cuidado y respeto. Para clarificar el significado de la dignidad como principio, se apela a la distinción entre principios y normas elaborada en el campo de la filosofía jurídica. La dignidad como estándar moral de la relación médico-paciente se ilustra en base a una serie de estudios empíricos.
Bioética y neuroética
Authors: Cortina Adela , Conill Jesús
Published: June 2019

La neuroética nace oficialmente a comienzos del siglo XXI, gracias al avance de las neurociencias, como ética aplicada vinculada a la bioética, pero también como neuroética autónoma. Como ética aplicada, aborda cuestiones cercanas a la bioética. Como neuroética autónoma, se enfrenta a problemas clásicos de la filosofía desde una perspectiva neurocientífica en sentido amplio. Dos cuestiones serán centrales en ella: diseñar un marco para seleccionar, interpretar e integrar los datos de las neurociencias acerca de la moralidad, y trazar el método -o métodos- adecuados para el nuevo saber. Curiosamente, en ambos casos la mayor parte de los neuroéticos dice inscribirse en posiciones naturalistas, pero realmente procede de forma no-naturalista. El artículo se propone analizar los distintos lados de la neuroética y sacar a la luz el método que realmente siguen los neuroéticos, que desmiente al naturalismo.
El monstruo fantástico posmoderno: entre la anomalía y la domesticación
Authors: Roas David
Published: June 2019

La ficción posmoderna no ha cesado de producir todo tipo de monstruos imposibles y, por ello, inquietantes, pero, al mismo tiempo, se están prodigando las obras (Crepúsculo es un ejemplo paradigmático) que banalizan y/o domestican al monstruo, despojándolo de su excepcionalidad, lo que provoca un curioso fenómeno (tras el que se oculta una visión inevitablemente conservadora del mundo): dotarlo de esa normalidad supone incorporarlo a la realidad, convertirlo en un posible más del mundo, y, con ello extirparle su original naturaleza imposible, situarlo dentro de la norma. Despojarlo de su monstruosidad. Lo que también le despoja de su fantasticidad... El objetivo de este artículo es reflexionar sobre las razones que han provocado ese proceso de domesticación del monstruo.
Espacio(s) teatral(es) y diversidad funcional
Authors: Hartwig Susanne
Published: June 2019

Esta contribución se plantea de qué manera actores con diversidad funcional cambian el espacio teatral. Se parte de la hipótesis de que las anomalías corporales hacen consciente la superposición de los dos hic et nunc del teatro, uno estético/simbólico y otro, físico/concreto. Tres ejemplos del teatro contemporáneo ilustran cómo este hecho se deja utilizar estéticamente: Esta breve tragedia de la carne, de Angélica Liddell (2015), Disabled Theater (2012), de Jérôme Bel, y Mi piedra Rosetta, de José Ramón Fernández, realizado por David Ojeda (2012). El análisis mostrará que en estas obras, la relación entre espacio escénico y espacio del espectador es inseparable del impacto del espectáculo entero. Las tres obras enfocan los conceptos exclusión, inclusión e intercambio.
Attention and its Role: Theories and Models
Authors: Drigas Athanasios , Karyotaki Maria
Published: June 2019

Motivation, affect and cognition are interrelated. However, the control of attentional deployment and more specifically, attempting to provide a more complete account of the interactions between the dorsal and ventral processing streams is still a challenge. The interaction between overt and covert attention is particularly important for models concerned with visual search. Further modeling of such interactions can assist to scrutinize many mechanisms, such as saccadic suppression, dynamic remapping of the saliency map and inhibition of return, covert pre-selection of targets for overt saccades and online understanding of complex visual scenes.
Design and Implementation of a Teaching Assistance Platform for College Students Based on ASP.NET
Authors: Yan Yu
Published: June 2019

Teaching assistance platforms for college students greatly promote the quality and resource utilization of college teaching, marking the direction of information-based modern higher education. This paper designs a student-centered, teacher-led college student teaching assistance platform. Following the object-oriented design method, the SQL was taken as the database, the ASP.NET was selected as the server-end language, and the ADO.NET was adopted as the database access technology. The platform structure and the e-Homework module were cited as examples to detail the design and implementation of the platform. The analysis shows that the platform can fully support all aspects of teaching and satisfy the specific requirements of college teaching. The research findings provide impetus to scientific teaching in colleges.
Experimental Study on Neural Feedback in Embedded System Teaching Processing Based on ERP Signal Analysis
Authors: Du Danbing
Published: June 2019

Embedded system teaching is an indispensable part in the process of computer language learning. This paper analyzes the neural feedback of embedded system learners in learning embedded systems by observing the generation and fluctua-tion of EEG signals. The ERP signals of computer learners in learning embedded system are monitored by ERP technology. The results show that the embedded system leads to the changes in EEG of computer linguists, and the changes of EEG amplitudes caused by different embedded systems. Combined with previous studies, it is shown that the embedded system processing has different effects on neural feedback. The analysis of EEG signals provides some theoretical basis and new ideas for embedded system teaching.
Static Watson-Crick Context-Free Grammars
Authors: Fong Wan Heng , Rahman Aqilahfarhana Abdul , Sarmin Nor Haniza , Turaev Sherzod
Published: June 2019

Sticker systems and Watson-Crick automata are two modellings of DNA molecules in DNA computing. A sticker system is a computational model which is coded with single and double-stranded DNA molecules; while Watson-Crick automata is the automata counterpart of sticker system which represents the biological properties of DNA. Both of these models use the feature of Watson-Crick complementarity in DNA computing. Previously, the grammar counterpart of the Watson-Crick automata have been introduced, known as Watson-Crick grammars which are classified into three classes: Watson-Crick regular grammars, Watson-Crick linear grammars and Watson-Crick context-free grammars. In this research, a new variant of Watson-Crick grammar called a static Watson-Crick context-free grammar, which is a grammar counterpart of sticker systems that generates the double-stranded strings and uses rule as in context-free grammar, is introduced. The static Watson-Crick context-free grammar differs from a dynamic Watson-Crick context-free grammar in generating double-stranded strings, as well as for regular and linear grammars. The main result of the paper is to determine the generative powers of static Watson-Crick context-free grammars. Besides, the relationship of the families of languages generated by Chomsky grammars, sticker systems and Watson-Crick grammars are presented in terms of their hierarchy.
Comparison of Engineering Skills with IR 4.0 Skills
Authors: Kamaruzaman Mohd F. , Hamid R , Mutalib A A , Rasul M S
Published: June 2019

In the heart of Industrial Revolution 4.0 (IR 4.0) is a set of rapidly evolving and converging technologies, which can bring sizeable consequences toward the economy, lifestyle, health, education, labour markets and skills development. The changes in the workforce setting of IR 4.0 have driven the need to obtain new skills that are aligned with the advancement of modern technology. This situation manifested itself since the current skills are no longer relevant and about to face a significant change in the entire field of work. Skills that are taught to the future graduates are out of sync with the current need of the industry, which eventually cost them their chance to fulfil the need of the workforce and increase the rate of unemployment among graduates. As a preparation to take up the challenges of the IR 4.0, graduates need to be exposed to appropriate skills to ensure their employment and to remain functioning in the ever-changing industry and technology environment. In this regard, this paper was done to compare the existing engineering skills with the new skills necessary for the IR 4.0. This article adopted a systematic review method considering previous studies on engineering skills required by the engineering accreditation bodies. Results from this study revealed seven skills identified as the gap in both sets of skills. These skills include analytical thinking and innovation; active learning and learning strategies; creativity, originality and initiative; technology design and programming; critical thinking and analysis; emotional intelligence; and system analysis and evaluation. Findings of this study can be used as a guidance to understand the current skills needed so that engineering graduates will have no problem in getting a job in the future.
New Silicone-Resin-Compounds for Casting and Molding Applications
Authors: Lambrecht Jens , Winterer Markus
Published: June 2019

Silicone resins are manufactured and supply in various delivery forms since decades. The impregnation of large electrical machines demonstrates a main application in the field of electrical insulation technology at the moment. Silicone resins are characterized by outstanding resistance to heat stress at high temperatures in general. Experience has shown that they are also very stable against exposure to UV radiation. Based on the expected very good property profile, Wacker Chemie AG developed a solvent-free, low-viscosity silicone resin for use as a binder for castable and moldable products. The article presents the chemical composition of silicone resins, the resulting properties of the resin and selected results of the extensive work for the evaluation of possible fillers and filler mixtures as well as first experience with the processing.
Modification of the Thermoset Injection Moulding Process for Shaping to Increase the Fibre Length in C/C-SiC Ceramics Produced by the LSI Process
Authors: Stiller Jonas , Nestler Daisy , Päßler Erik , Kempe Fabian , Wätzig Hendrik , Ahmad Husam , Kroll Lothar , Sommer Michaela , Wagner Guntram
Published: June 2019

Ceramic-matrix composites (CMC) made of carbon and silicon carbide dual matrix reinforced with carbon fibres (C/C-SiC) have exceptional heat, thermal shock, creep, and wear resistance, while also having little density and high strength. In comparison to monolithic ceramics, CMC possess ductility and damage tolerance, which opens this material for severe applications. Starting in space applications, this material is today well established in friction applications, where lightweight high-performance brakes securely decelerate e.g. luxury cars or elevators. The high production costs still limit the broad application like as brake discs in standard passenger cars, although less weight, better performance and longer lifetime. The industrial used production process is the liquid silicon infiltration (LSI) with it three steps: green body shaping, pyrolysis and silicon infiltration. In this work, the shaping process of the carbon fibre reinforced plastic (CFRP) green body, is done by thermoset injection moulding. The application of plastic production processes like compounding and injection moulding in the liquid silicon infiltration process route, enables large-scale manufacturing. However, the screws and high shear forces inside the plastic processing machines significantly shorten the fibres. This paper describes the pros and cons of thermoset injection moulding in the LSI route, as well as the development and effect of different reinforcement types in dependence of their fibre length, since several energy dissipation mechanisms bases on a minimum length of reinforcement fibres in CMC. Various raw materials like short and chopped fibres with different length, rovings, and different approaches to receive longer fibres and their outcomes are presented. The mechanical properties show promising values and the micrographs display the infiltration status and crack development inside the specimen.
Development of Tailored Hybrid Laminates: Manufacturing of Basalt Fibre Reinforced Thermoplastic Orthoses with Aluminum Thin Sheets
Authors: Karapepas Christos , Trautmann Maik , Todt Andreas , Al-Obaidi Amar , Nendel Sebastian , Kräusel Verena , Wagner Guntram
Published: June 2019

Nowadays, orthoses are made from fibre reinforced thermoset based composites with a high manual labor input. These thermoset based orthoses are no longer formable, which brings forth a significant disadvantage. Hence, hybrid laminates consisting of fibre reinforced thermoplastic films and thin metal sheets can replace successive thermoset based systems due to their advantages of higher formability and the suitability for mass production. In the present work, various surface treatment methods like pickling or mechanical blasting have been used on thin metal sheets to increase the adhesive and shear strength of the produced thermoplastic based hybrid laminates. The modified metal sheets were further combined with basalt fibre reinforced interlayers to manufacture overlap samples, which were used to determine the tensile shear strength. In addition, the roughness of the modified metal sheets has also been investigated. Moreover, the consolidation parameters such as pressure, holding time and temperature have been varied for the production of hybrid laminates using hot-pressing process and then the microstructural images have been recorded. Finally, the mechanical properties of the produced hybrid laminates have been tested by means of a three-point bending test and the interlaminar shear strength has been analyzed.
Development of a Laser Structuring Process for Ceramic Coatings on Injection Molding Tools Produced by MOCVD
Authors: Sommer Michaela , Fornalczyk Gregor , Mumme Frank
Published: June 2019

To increase product quality injection molding tools are equipped with innovative tempering technologies. The customers strive for the technology with the lowest energy consumption. Ceramic materials like yttria-stabilized zirconia (YSZ) are able to thermally insulate tool surfaces providing a more precise temperature regulation with intent to shorten cycle times as well as to decrease energy demands during the molding process. High quality ceramic thin films could be applied by metalorganic chemical vapor deposition (MOCVD). Laser machining technologies have been developed for machining the ceramic materials. In this work we demonstrate the fabrication of zirconia based thin films on steel tools via MOCVD using solid metalorganic precursors. Shorter coating times and a solvent free process are some of the advantages of our new developed coating process. The ultrashort pulse laser processing (USPLP) was used to structure the developed MOCVD coating. Using this technology the ceramic material undergoes no thermal stress cracks, because USPLP is characterized by the preference of cold material removal. The laser processing procedure was developed by working out machining parameters for the different materials. The difference between steel and ceramic in the removal behavior was determined immediately so that a machining strategy for the ceramic CVD coating could be designed successfully. The implementation of defined roughness and a carbon fiber like structure in the coating were realized. Coated and laser-structured injection molding tools were tested regarding their desired properties under production conditions.
Environmental Compatibility of Carbon Reinforced Concrete: Irrigated Construction Elements
Authors: Weiler Lia , Vollpracht Anya
Published: June 2019

To foster a sustainable deployment of the innovative composite material ‘carbon concrete composite’ in the building sector, it is necessary to ensure its resource efficiency and environmental compatibility. The Institute for Building Materials Research of the RWTH Aachen University is therefore investigating the leaching behavior of this material, especially for the case of irrigated façade elements. Laboratory and outdoor exposure tests are run to determine and assess the heavy metal and trace element emissions by leaching. Feasible interconnections between laboratory and outdoor examinations can be used to develop a faster testing of future composite materials. Current results show no critical release of environmental harmful substances from carbon concrete composite.
Development of a Modular Draping Test Bench for Analysis of Infiltrated Woven Fabrics in Wet Compression Molding
Authors: Albrecht Fabian , Zimmerling Clemens , Poppe Christian , Kärger Luise , Henning Frank
Published: June 2019

The wet compression molding (WCM) process enables short cycle times for production of fiber-reinforced plastics due to simultaneous infiltration, viscous draping and consolidation in one process step. This requires a comprehensive knowledge of occurring mutual dependencies in particular for the development of process simulation methods and for process optimization. In this context, it is necessary to develop suitable test benches to enable an evaluation of the outlined viscous draping behavior. In order to evaluate and suitably design the draping process, grippers are mounted on a surrounding frame, which enables targeted restraining of the local material draw-in during forming. In supporting the development of the new test bench, first experimental and simulation results are compared, which thereby enables a first validation of the simulation approaches. Results show a good agreement between experimental and numerical results in terms of shear deformation and final gripper displacement under dry and viscous conditions. Results recommend that future development for investigations of viscous draping effects should focus an enabling measurement of gripper displacement during the forming process. Beyond that, the modular test bench design enables experimental and virtual draping optimization and deduction of blank holder concepts for WCM tools.
Temperature- and Time-Dependent Penetration of Surface Structures in Thermal Joining of Plastics to Metals
Authors: Schricker Klaus , Bergmann Jean Pierre
Published: June 2019

The temperature- and time-dependent penetration of surface structures is examined in thermal joining between polypropylene and aluminum. Experimental and numerical investigations were carried out for spot joints in order to describe the main effects on structure penetration. Further investigations were performed in a half-section setup to gain information directly from the joining zone. The thermal expansion of the thermoplastic material as well as the temperature distribution in the melting layer were identified as key parameters for structure filling on the metal surface.
Quasi-Static Characterization of Polyamide-Based Discontinuous CFRP Manufactured by Additive Manufacturing and Injection Molding
Authors: Striemann Patrick , Hülsbusch Daniel , Niedermeier Michael , Walther Frank
Published: June 2019

Generating serial components via additive manufacturing (AM) a deep understanding of process-related characteristics is necessary. The extrusion-based AM called fused layer manufacturing (FLM), also known as fused deposition modeling (FDM™) or fused filament fabrication (FFF) is an AM process for producing serial components. Improving mechanical properties of AM parts is done by adding fibers in the raw material to reinforce the polymer. The study aims to create a more detailed comprehension of FLM and process-related characteristics with their influence on the composite.Thereby, a short carbon fiber-reinforced polyamide (CarbonX™ Nylon, 3DXTECH, USA) with 12.5 wt.‑% fiber content, 7 μm fiber diameter, and 150 to 400 µm fiber length distribution was investigated. To separate process-related characteristics of FLM, reference specimens were fabricated via injection molding (IM) with single-batch material. For the mechanical characterization, quasi-static tensile tests were carried out in accordance to DIN 527‑2. Quality assessment including void content and void distribution was performed via micro-computed tomography (CT).The mechanical characterization clarifies effects on mechanical properties depending on process-related characteristics of FLM. CT scans show higher void contents of FLM specimens compared to IM specimens and void orientation dependent on printing direction. FLM shows process-related characteristics which generally strengthen mechanical properties of polymers. Nevertheless, tensile strength of FLM specimens decrease by more than 28% compared to quasi-homogenous IM specimens.
Mechanical Design of Intersection Points of Tailored Fiber Placement Made Carbon Fiber Reinforced Plastic Truss-Like Structures
Authors: Richter Emanuel , Spickenheuer Axel , Bittrich Lars , Uhlig Kai , Heinrich Gert
Published: June 2019

The presented study emphasizes a favored design for carbon fiber reinforced plastic fiber patterns at intersection points of truss-like structures made with the Tailored Fiber Placement technology. Three different pattern types have been experimentally and numerically analyzed. A straight fiber crossing is the most simple design, but it cannot compete against a fanned out fiber pattern regarding structural stiffness, where fiber spacing increases with increasing crossing distance. A pattern design, where belt and web fiber paths merge, is the most preferred design due to a minimum of material waste, however it exhibits lower stiffness compared to the fanned out pattern.
Novel Approach in B-Staging of an Epoxy Resin for Development of rCF Non-Woven Prepregs for RTP Processing
Authors: Goergen Christian , Klingler Andreas , Grishchuk Sergiy , May David , Wetzel Bernd , Mitschang Peter
Published: June 2019

A novel B-stage resin system is developed for the „Resin Transfer Pressing“ (RTP) process. This composite manufacturing technique makes use of nonwoven and recycled carbon fibres (rCF) that are oversaturated with a thermosetting resin. The new resin system is based on two different hardeners, allowing to easily impregnate the rCF, storing the semi-finished parts at room temperature and finally curing them via compression molding. It is shown that a commercially available resin system can be tailored to the required needs by the smart combination of state-of-the art, latent hardener systems.The present study focusses on the route for B-staging of the resin system. The viscosity for impregnation and oversaturation was adjusted to be in the range of 5 to 40 Pa·s at 60°C. The viscosity increases to above 50 Pa·s at room temperature, allowing storage and handling of the semi-finished parts and processing them whenever it is required. Choosing a proper processing temperature is important during the B-staging process to avoid any unintended activation of the second hardener, which is responsible for the final curing stage of the system.
Development of a Variable Gridshell for Application in Mobile Architecture
Authors: Rudolph Enrico , Müller Christian , Ehrlich Andreas , Gelbrich Sandra , Kroll Lothar
Published: June 2019

Within the research project a variable gridshell in lightweight design was developed that permit the building of free-formed mobile architectures. The construction consists of a large number of straight length-adjustable bars pin-jointed via so-called knots and enables extremely efficient and stable support structures with high potential for lightweight construction.
Combined In Situ X-Ray Computed Tomography and Acoustic Emission Analysis for Composite Characterization - A Feasibility Study
Authors: Bartkowiak Miriam , Schoettl Ludwig , Elsner Peter , Weidenmann Kay André
Published: June 2019

Fiber reinforced plastics show a wide range of different damage mechanisms such as matrix cracking, fiber breakage and interface failure. These can be observed in damaged specimens by means of volumetric images acquired by computed tomography (CT). As each failure mechanism causes a characteristic acoustic emission (AE) signal, AE analysis is a promising tool to identify damage mechanisms and offers the advantage that a real-time observation of the damage evolution during the testing period is possible. For a correlation of damage mechanisms and AE events, AE analysis was combined with in- situ CT measurements. This combined approach was validated by means of a 3-point-bending test on a discontinuous glass fiber reinforced sheet molding compound (GF-SMC) in which AE signals were acquired during loading using two high frequency piezoelectric sensors. At times of increasing AE activity, the test was interrupted in order to carry out a CT-scan of the specimen under load. AE events could subsequently be linked with the damage mechanisms observed in the CT-scans at different stages of damage to identify signal features that are characteristic for a certain mechanism. The sources of the signals could be localized and were in line with the actual location of damage.
Potential for Use of Veneer-Based Multi-Material Systems in Vehicle Structures
Authors: Käse David B. , Piazza Giovanni , Beeh Elmar , Friedrich Horst E. , Kohl Daniel , Nguyen Hoa , Berthold Dirk , Burgold Claudia
Published: June 2019

In the past, the focus for the development of modern vehicle structures was very much on lightweight construction. However, there are increasing aspirations to develop not only light but also sustainable solutions which use resources efficiently. As a result, natural materials become more attractive compared to conventional lightweight construction materials. The "For (s) tschritt" research project investigates the use of veneer-based multi-material systems in vehicle structures. For this purpose, various concepts were developed, ranging from a use of the material to reinforce thin sheet metals to structural components which are produced completely from wood and are only reinforced locally. In order to evaluate the aspired solutions, generic components were derived, manufactured at the Department for Cutting and Joining Manufacturing Processes of the University of Kassel (TFF) and the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut (WKI), and tested at the Institute of Vehicle Concepts of the German Aerospace Center (DLR). The advantages of the use of wood are particularly evident in structures which are subjected to bending stress and pressure loads: As a result of the lower density, they can be designed with reinforcement. This allows the second moments of inertia to be increased without affecting the weight. The disadvantages of the natural material, such as reduced reproducibility and the complex failure behaviour, are offset by systematic hybridisation of wood and the use of veneer multilayer composites.
Influence of Distinct Manufacturing Processes on the Microstructure of Ni-Based Metal Matrix Composites Submitted to Long Thermal Exposure
Authors: Lemos Georges , Fredel Márcio C. , Pyczak Florian , Tetzlaff Ulrich
Published: June 2019

Metal Matrix Composites (MMCs) are known for their remarkable properties, by combining materials from different classes. Ni-based MMCs are a promising group of heat-resistant materials, targeting aerospace applications. A discontinuously reinforced Inconel X-750/TiC 15 vol.% MMC was proposed for use in lighter, creep resistant turbine elements, with the aim to endure service temperatures up to 1073 K (800 °C). However, their microstructural stability at high temperatures for long periods of time remained to be further investigated. To address this need, specimens were produced by both conventional hot pressing and spark plasma sintering, using powders milled by low and high energy processes, followed by long isothermal aging. The treatments were conducted at 973 and 1073 K, for times between 50 and 1000 hours. The resulting samples were investigated with XRD and EDS techniques for phase analysis. In addition, measurements of hardness were made to monitor changes in mechanical behavior. It was found that, for each different manufacturing process, the amount, distribution and size of γ’ and other precipitates notably vary during the overaging process. Consequently, the amount of elements kept in solid solution also shifted with time. Furthermore, the study shows how distinct initial microstructures, resulting from diverse fabrication processes, differently impact the microstructural stability over long times of exposure to high temperatures.
Comparison of Low-Velocity Impact Damage Behavior of Unidirectional Carbon Fiber-Reinforced Thermoset and Thermoplastic Composites
Authors: Schimmer Florian , Ladewig Sven , Motsch Nicole , Hausmann Joachim M. , Ehrlich Ingo
Published: June 2019

This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, laminates with an epoxy (EP) and a polyether ether ketone (PEEK) matrix in a quasi-isotropic (QI) [+45/0/-45/90]2s and an orthotropic (OT) fiber lay-up [0/90]4s were manufactured. To eliminate the influence of variant fiber systems, the thermoplastic tape and the thermoset prepreg contain similar carbon fibers (CF). After impact testing with three different impact energies, inner damages were investigated by using ultrasonic analyses. To get a deeper understanding of the interior damage mechanisms, cross sections of the damaged areas were examined via reflected light microscopy. By using these destructive and non-destructive test methods, significant differences in the damage behavior of composites with thermoplastic and thermoset matrix systems were identified for both laminate lay-ups.
Removal of Alizarin Red Dye Using Strong Ionization Discharge Technology
Authors: Yin Lan Lan , Yi Rong Jie , Yi Chen Wu , Geng Ting Ting , Nawaz Muhammad Imran , Junior Prince Asilevi
Published: June 2019

The degradation of Alizarin red dye (Anthraquinone) was investigated using a novel technique of strong ionization discharge to generate high oxidation active species from oxygen. Under the optimum conditions, AR dye was almost removed with degradation rate reaching 95%, by radicals such as •OH and O3 generated within the strong ionization discharge reactor. The intermediate products were analyzed by ultraviolet (UV) spectroscopy, total organic carbon (TOC) analysis, liquid chromatography-mass spectrometry (LC-MS) and ion chromatography (IC) to validate the degradation efficiency of the strong ionization discharge for AR dye and to deduce its possible decomposition pathway. Finally, It has been confirmed that the sulfur element on AR molecule results into sulfate, an environmentally friendly substance. This work shows that the strong ionization discharge can efficiently be used for the degradation of Anthraquinone dyes as well as other extensively used textile dyes.
Effects of Conductive Phase on Properties of Concrete
Authors: Fan Bao Zhen , Fang Zheng Gang , Liu Rui , Shen Hong Bing
Published: June 2019

In this paper, the effects of graphite and carbon fiber on the properties of concrete were studied, the 28d compressive strength and electrical resistivity of concrete were measured, and the microstructure of concrete was observed. The results show that the graphite could improve the conductivity of concrete meanwhile reduce the compressive strength, and that the carbon fiber can improve the compressive strength of concrete, but its influence is considerably limited. Only when the mixing amount of graphite is higher than 1%, the compressive strength of concrete will increase along with the increase of mixing amount of carbon fiber, and the lamellar structure of graphite will be obvious, and the lamellar connection between graphite flakes will be in good condition. When the mixing amount of carbon fiber is 0.8%, dense connection will be formed between the carbon fiber & graphite and the hydration products. The combined mixture of graphite and carbon fiber can form a dense and relatively complete conductive network and is beneficial to the improvement of compressive strength of concrete.
Fast Activating Persulfate by Crystallization of Fe-Based Metallic Glasses with External Energy
Authors: Liang Shun Xing , Zhang Lai Chang
Published: June 2019

Very recently, crystallization of metallic glasses (MGs) has presented promising properties in the catalytic field. This work has investigated enhanced catalytic performance of crystallized Fe78Si9B13 ribbons for fast activating persulfate (PS) with assistance of UV-vis light and heat. The ribbons were obtained by annealing at 750°C (Fe-A750) and cibacron brilliant yellow 3G-P (BY 3G-P) dye was used as pollutant. The results indicated that UV-vis light had limited capability to enhance PS activation efficiency by crystallized ribbons while the reaction rate using heat at 65°C was 7.5 times higher than at 25°C, suggesting an advanced performance with heat assistance of Fe-A750 ribbons. Activation energy ∆E for Fe-A750 was measured as 44.5 kJ mol-1. In addition, 5 times reusability could be achieved for Fe-A750 ribbons under 45°C without catalytic decay. The surface morphologies of glassy ribbons, as-annealed Fe-A750 ribbons, HCl-treated Fe-A750 ribbons and after-reused Fe-A750 ribbons have also been systematically studied. This work provides a novel clue to promote applicability of novel crystallized ribbons from MGs.
Characterization of Cooling Rate and Microstructure of Rapidly Solidified Spherical Mono-Sized Sn-1.0Ag-0.5Cu Particles
Authors: Hu Ying Yan , Wang Jun Feng , Li Can , Li Jian Qiang
Published: June 2019

Spherical mono-sized Sn-1.0Ag-0.5Cu (wt.%) particles with diameter ranging from 124.0 to 337.4μm were prepared by the pulsated orifice ejection method (termed “POEM”).These spherical Sn-1.0Ag-0.5Cu particles exhibit a good spherical shape and a narrow size distribution, suggesting that liquid Sn-1.0Ag-0.5Cu can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical Sn-1.0Ag-0.5Cu particles was studied with a specific focus on different particle diameter during the rapid solidification. The cooling rate of spherical Sn-1.0Ag-0.5Cu particles with different diameter was evaluated by the Newton’s cooling model. It is revealed that the cooling rate decreases gradually with the increase of particle size during the rapidly solidified process. When the particle diameter is equal to 75 μm, the cooling rate of the Sn-1.0Ag-0.5Cu particle achieves 4.30×103 K/s which indicates that smaller particles can rapidly solidified due to their higher cooling rate. Meanwhile, the cooling rate decreases rapidly when the particle diameter increases between 75 and 100 μm. Furthermore, the different particle diameter with different cooling rate has a great influence on the solidification microstructure of Sn-1.0Ag-0.5Cu particles. The cooling rate and grain boundary size decreases with the increase of particle diameter during the rapid solidification. In addition, the phase size of βSn increases with the decrease of particle size. Smaller particles have relatively high cooling rate and it gives less solidification time as compared to larger particles. It is an effective route for fabrication of high-quality spherical Sn-1.0Ag-0.5Cu particles. Keywords: Spherical Sn-1.0Ag-0.5Cu particles; Rapid solidification; Structural; Cooling rate
Acoustic Emission Study of Fatigue Crack Propagation of Weld Joint for X52 Pipeline Steel
Authors: Chang Hong
Published: June 2019

The crack propagation of different weld joint samples were detected by acoustic emission (AE) technique. The samples were from the basic metal, weld seam and heat affected zone (HAZ), The results showed that the crack growth rate of basic metal was higher than weld seam and HAZ because of the transverse compressive residual stress in joint. But the coarse of grains was the reason for higher rate of weld seam than that of HAZ. And AE waveforms of crack propagation from three microstructures were different. The most compositions of AE signals were higher frequency of 300KHz for weld seam and lower one of 100KHz for basic metal and HAZ.
Structural Characterization of Low Carbon Foil by Asymmetrical Rolling
Authors: Bai Feng Mei , Li Yan Yan , Wang Jia , Liu Xiang Hua , Fang Jin Xiu , Huang Zhen Yi , Song Meng
Published: June 2019

At room temperature, the low carbon steel were cold rolled from 0.5 mm to 1 μm without intermediate annealing by asymmetrical rolling (ASR) process. the microstructure were investigate by Electron Backscatter Diffraction (EBSD) and transmission electron microscopy (TEM). Lath structure (~300 nm) and local nanograins (~60nm) were obtained through ASR with extensibility up to 50,000%. The high angle boundaries were predominant. The results indicated that inhomogeneous deformation and combination deformation mechanism of dislocation slip and grain boundary slip in the foil ASR process.
Recent Advances and Trends in Heterogeneous Integrations
Authors: Lau John H.
Published: June 2019

The recent advances and trends in heterogeneous integrations are presented in this study. Emphasis is placed on: (A) the definition of heterogeneous integrations, (B) the classifications of heterogeneous integrations such as heterogeneous integrations on (a) organic substrates, (b) silicon substrates (through-silicon via interposers), (c) silicon substrates (bridges), (d) fan-out RDL (redistribution-layer) substrates, and (e) ceramic substrates, and (C) the examples of heterogeneous integrations of chip-to-chip, chip-to-wafer, memory stacks, package-on-package, light-emitting diode, CMOS image sensors, microelectro-mechanical systems, vertical-cavity surface-emitting laser, and photodetector. The trends of heterogeneous integrations are also presented.
Head-on-Pillow Defect Detection: X-Ray Inspection Limitations
Authors: Bruno Lars , Gustafson Benny
Published: June 2019

Both the number and the variants of ball grid array packages (BGAs) are tending to increase on network printed board assemblies with sizes ranging from a few millimeter die size wafer level packages with low ball count to large multidie system-in-package (SiP) BGAs with 60–70 mm side lengths and thousands of I/Os. One big challenge, especially for large BGAs, SiPs, and for thin fine-pitch BGA assemblies, is the dynamic warpage during the reflow soldering process. This warpage could lead to solder balls losing contact with the solder paste and its flux during parts of the soldering process, and this may result in solder joints with irregular shapes, indicating poor or no coalescence between the added solder and the BGA balls. This defect is called head-on-pillow (HoP) and is a failure type that is difficult to determine. In this study, x-ray inspection was used as a first step to find deliberately induced HoP defects, followed by prying off of the BGAs to verify real HoP defects and the fault detection correlation between the two methods. The result clearly shows that many of the solder joints classified as potential HoP defects in the x-ray analysis have no evidence at all of HoP after pry-off. This illustrates the difficulty of determining where to draw the line between pass and fail for HoP defects when using x-ray inspection.
Rotator interval closure: inconsistent techniques and its association with anterior instability. A literature review
Authors: Karovalia Shahin Nizarali , Collett David J. , Bokor Desmond
Published: June 2019

The Rotator interval (RI) is an anatomic space in the anterosuperior part of the glenohumeral joint. An incompetent or lax RI has been implicated in various conditions of shoulder instability and therefore RI has been frequently touted as an area that is important in preserving stability of the shoulder. Biomechanical studies have shown that repair of RI ligamentous and capsular structures decreases glenohumeral joint laxity in various directions. Clinical studies have reported successful outcomes after repair or plication of these structures in patients undergoing shoulder stabilization procedures. Although varieties of methods have been described for its closure, the optimal surgical technique is unclear with various inconsistencies in incorporation of the closure tissue. This in particular makes the analysis of the RI closure very difficult. The purposes of this study is to review the structures of the RI and their contribution to shoulder instability, to discuss the biomechanical and clinical effects of plication of RI structures in particular to anterior glenohumeral instability, to delineate the differences between an arthroscopic and open RI closure. Additionally, we have proposed a new classification system describing various techniques used during RI closure.