bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ensemble of Bayesian Neural Networks for Exoplanetary Atmospheric Retrieval
Authors: Cobb Adam D. , Himes Michael D. , Soboczenski Frank , Zorzan Simone , O’Beirne Molly D. , Güneş Baydin Atılım , Gal Yarin , Domagal-Goldman Shawn D. , Arney Giada N. , Angerhausen Daniel ,   2018 NASA FDL Astrobiology Team II
Published: June 2019

Machine learning (ML) is now used in many areas of astrophysics, from detecting exoplanets in Kepler transit signals to removing telescope systematics. Recent work demonstrated the potential of using ML algorithms for atmospheric retrieval by implementing a random forest (RF) to perform retrievals in seconds that are consistent with the traditional, computationally expensive nested-sampling retrieval method. We expand upon their approach by presenting a new ML model, plan-net, based on an ensemble of Bayesian neural networks (BNNs) that yields more accurate inferences than the RF for the same data set of synthetic transmission spectra. We demonstrate that an ensemble provides greater accuracy and more robust uncertainties than a single model. In addition to being the first to use BNNs for atmospheric retrieval, we also introduce a new loss function for BNNs that learns correlations between the model outputs. Importantly, we show that designing ML models to explicitly incorporate domain-specific knowledge both improves performance and provides additional insight by inferring the covariance of the retrieved atmospheric parameters. We apply plan-net to the Hubble Space Telescope Wide Field Camera 3 transmission spectrum for WASP-12b and retrieve an isothermal temperature and water abundance consistent with the literature. We highlight that our method is flexible and can be expanded to higher-resolution spectra and a larger number of atmospheric parameters.
State of spring phytoplankton and quality of the Kenozero waters in 2018
Authors: Otchenasch Natalia , Dvoryankin Gennadii , Imant Ekaterina
Published: June 2019

Phytoplankton constitutes a key part of all aquatic ecosystems. It produces organic matter, thus forming the first level of food chains in water bodies. In addition, phytoplankton plays a major role in the water quality formation. The studies of algocoenosis always remain relevant, since the obtained data provides important information on the ecological status of water bodies. This information can subsequently be used for planning and implementing environmental measures, which are particularly significant for water bodies located in specially protected areas. National parks existing for the purposes of nature preservation, education and research are also designed for tourism, which makes their ecosystems more vulnerable. Population residing in such territories and its economic activity may also carry some environmental risks, which necessitates regular complex observations. This paper covers the state of spring phytoplankton community of Lake Kenozero in 2018, its qualitative and quantitative characteristics (species composition, abundance and biomass). In the course of research, we identified 70 phytoplankton taxa belonging to seven divisions: Bacillariophyta, Dinophyta, Chlorophyta, Cyanophyta, Chrysophyta, Xanthophyta and Euglenophyta. The dominant species complex included diatoms (Asterionellaformosa, Melosiragranulata, Tabellariafenestrata), representatives of Dinophyta (Gymnodinium sp.), as well as small euglenoids. Species diversity was estimated using the Shannon-Weaver index. Aquatic environment contamination was assessed, i.e. the saprobity index was calculated and the class of surface water quality was determined. According to the water quality classification of water bodies and watercourses by hydrobiological indicators, Lake Kenozero was assigned the second class of water quality (moderately polluted).
Two caves in western Honduras are important for bat conservation: first checklist of bats in Santa Bárbara
Authors: Turcios-Casco Manfredo Alejandro , Ordoñez Mazier Diego Iván , Soler Orellana José Alejandro , Ávila-Palma Hefer Daniel , Ordoñez Trejo Eduardo Javier
Published: June 2019

Caves are important reservoirs for species, including bats, but in Honduras there is little known information about these biodiverse ecosystems. We describe the importance of two caves in Ceguaca in western Honduras, based on the species richness of each cave. From December 2015 to May 2016, we used three mist-nets in seven journeys (74.27 mist-net/hours). We captured 139 bats belonging to 23 species of four families. We recorded 10 species in the crop of Quita Sueño, 10 in the cave of El Peñón, and 12 in the cave of Monte Grueso. In overall, 17% of the bats were captured in the crops of Quita Sueño, 62% in the cave of Monte Grueso, and 21% in the cave of El Peñón. About 9% of bat species of the total account for Honduras could be found in the cave of El Peñón, and 10% in the cave of Monte Grueso. If we consider the number of the species that have been recorded since 1979, between 20.9 and 49.2% of the expected species are still unrecorded, this suggests that despite low sampling effort there is a high diversity. However, the diversity of bats species using these caves embraced on the Tropical Dry Forest of Ceguaca is threatened by the fragmentation of the ecosystem due to the following reasons: intentional fires in the caves, extensive cattle raising, replacement of native plants with extensions of crops, and human-vampire conflicts (Desmodusrotundus).
Le Quantified Self en question(s)
Authors: Dagiral Éric , Licoppe Christian , Martin Olivier , Pharabod Anne-Sylvie
Published: June 2019

Cet article présente les travaux de sciences sociales – sélectionnés principalement au carrefour de la sociologie, de l’anthropologie et des STS – consacrés au thème du Quantified Self (QS) depuis le début des années 2010. Conçu comme un assemblage d’outils, de pratiques, de techniques et de représentation, le QS y figure à la fois un mouvement sociopolitique d’usagers-pionniers et de concepteurs, des dispositifs de quantification, ainsi qu’une variété de pratiques de self-tracking inscrites historiquement. Après avoir analysé la construction du QS en tant que promesse et sa diffusion, l’état des lieux thématise l’économie morale de ces objets : management de soi ; discipline, contrôle et surveillance ; et formes d’expériences. Une troisième partie organise les études d’usage selon les contextes dans lesquels ils s’inscrivent (santé et prévention, expérimentations, prescription au travail ou à l’initiative des particuliers…). Enfin, les apports des travaux consacrés à la mise en chiffres des individus sont remis en perspective à l’aune de la sociologie historique de la quantification.
Tensions épistémiques dans les écrits d’ingénieurs
Authors: Compagnone Claude
Published: June 2019

Le but de cet article est de montrer comment des ingénieurs du domaine agricole définissent et produisent des supports écrits de communication adressés directement ou indirectement à des publics différents, aux exigences propres. Ces ingénieurs appartiennent à un même service d’un Institut technique agricole et conjuguent dans leur activité un travail de développement et de recherche. En nous appuyant sur leur discours, nous rendons compte de la façon dont ils conçoivent, dans leur forme et dans leur mode de production, différents types d’écrits. Nous faisons apparaître comment la construction de ces supports amène à des conflits des normes entre ces ingénieurs et leurs responsables. Ces supports scripturaux ne sont pas utilisés selon les cas pour connecter simultanément les mêmes acteurs, ils ne concernent pas le même « horizon de communautés » et peuvent articuler différentes formes de connaissances. Si, pour les uns, il s’agit de produire des textes scientifiquement valables au regard de la communauté scientifique, pour les autres, il s’agit de pouvoir répondre aux questions de développement de leurs partenaires régionaux.
Les scandales Vanessa Tchatchou et Monique Koumateke
Authors: Afom Frank
Published: June 2019

Le présent article affirme l’hypothèse selon laquelle les réseaux sociaux numériques seraient devenus un espace privilégié pour protester, contester, voire « s’insurger » contre les gouvernants au Cameroun. Selon son heuristique, c’est le caractère postautoritaire de l’État qui explique l’expression de ce dissentiment sur Internet. Afin de discuter cette hypothèse, nous nous sommes intéressé aux scandales Vanessa Tchatchou et Monique Koumateke, dont nous avons suivi les réactions des internautes indignés et les propos exprimés à cette occasion par certains acteurs politiques sur Facebook à travers des écrits de journalistes relayés sur quelques plateformes numériques. Si cette protestation est vectrice d’un empowerment des citoyens, ses supports numériques permettent à ces derniers d’exercer la fonction contre-démocratique participant ainsi à un renouvellement de l’espace public au Cameroun.
Une identité recomposée
Authors: Seulin Christian
Published: June 2019

L’auteur, psychanalyste consultant en service de transplantation, décrit les aléas de la dynamique d’appropriation subjective des greffons dans les greffes bilatérales de mains et de face. Pour les greffés des mains, cela permet presque toujours une recomposition de l’identité subjective. Pour les greffés de face, une identité sociale est retrouvée, mais le rôle de la réflexivité dans le regard porté sur le visage comme la mise en jeu des zones érogènes entravent souvent d’authentiques retrouvailles identitaires.
Les transidentités, une autre écoute ?
Authors: Caraman Francine
Published: June 2019

Affirmer une transidentité est considéré ici dans l’intensité du mouvement psychique à l’œuvre chez ces patients au confluent de deux cultures du sexuel et du genre. Là où tout un chacun est renvoyé à son sentiment intérieur d’être un homme ou une femme, quitter un genre pour un autre est un choix qui s’impose comme solution. L’auteur a choisi de suivre les traces du « disparu », d’un certain congé de soi, énigmatique pour le patient comme pour le psychanalyste, au cours d’un voyage clinique.
Un trouble dans l’identité : la paranoïa masculine
Authors: Joubert Martin
Published: June 2019

La paranoïa ne s’organise pas de la même façon chez les hommes et les femmes. Le lien aux objets primaires et le narcissisme s’y engagent différemment. L’assise que constitue pour le garçon le fantasme originaire de la scène primitive et une généalogie paternelle dont il pourrait se prévaloir, ne peut être assumée. À la place, un fantasme d’engendrement de soi-même voire d’une lignée, se nourrit de l’envie pour la mystérieuse puissance procréatrice des femmes. Une identification de surface, par imitation, à des imagos maternelles primitives totipotentes, actualisées jusqu’à la caricature dans le comportement, peut alors tenir lieu d’identité d’emprunt.
L’identité dans la transmission. Avec Kafka et Freud
Authors: Guillou Julien
Published: June 2019

En s’appuyant sur les œuvres de Kafka et de Freud, ce texte a pour but de réfléchir au lien entre identité et transmission. Entre infidélité à l’héritage et reconnaissance d’une dette, nous faisons l’hypothèse qu’un travail psychique de transmission permet de penser une identité inachevée et en devenir, une identité en construction.
Se battre pour pleurer : Flamenco et identités sexuées
Authors: Galiana Éléonore
Published: June 2019

Marqueur de la culture gitane, le flamenco encourage l’individu, dans le respect des traditions, à exprimer son identité, notamment sexuée. L’analyse des contradictions entre les niveaux manifeste et latent de cet art en révèle la subtilité et la puissance en ce qu’il permet de transcender les normes qui le soutiennent et, chez les deux sexes, de favoriser la conflictualisation psychique et l’ambivalence, au détriment d’une différenciation rigide, voire clivée, des genres.
Georges Canguilhem et les professeurs de philosophie
Authors: Vermeren Patrice
Published: June 2019

Qu’est-ce qu’enseigner la philosophie en France, et singulièrement dans l’après-coup de la Seconde Guerre mondiale, qui a promu la référence à Hegel comme incontournable, posant la question du sens de l’histoire, et où l’humanisme, le marxisme et l’existentialisme sont les problèmes ou les doctrines de l’heure ? D’abord, répond Georges Canguilhem, exercer un métier de professeur, enseignant – singulièrement dans les lycées – une discipline qui permet aux élèves de cultiver l’autonomie du jugement et de la réflexion. Et si la philosophie est un examen critique et une assignation de valeurs, traitant des attitudes de l’homme devant la vie, sa transmission passe aussi par la lecture des textes des philosophes. Mais pour autant, il s’agit d’éviter l’écueil du cimetière des doctrines et de promouvoir la rencontre de deux libertés.
La présence de Rousseau dans la réflexion éducative de Pestalozzi
Authors: Potestio Andrea
Published: June 2019

Cet essai se concentre sur la présence de certains aspects des théories éducatives de Rousseau dans les écrits de Pestalozzi, en particulier les écrits juvéniles. Il est un peu restrictif de considérer Pestalozzi comme un éducateur qui a tenté d’appliquer, dans des situations éducatives concrètes, l’éducation naturelle de Rousseau, car il existe des éléments de discontinuité significatifs dans la pédagogie des deux auteurs.
¿Clonar humanos? Límites de la eugenesia
Authors: Ayala Francisco J.
Published: June 2019

La humanidad no solo ha evolucionado, sino que continúa evolucionando. ¿Hacia dónde va la evolución humana? La evolución biológica está dirigida por la selección natural, que no es un proceso benevolente que guíe a las especies hacia un éxito seguro. El resultado final puede ser la extinción. Los avances en genética, biología molecular y biomedicina han hecho posible manipular, rápida y efectivamente, la constitución genética de la humanidad. La terapia genética puede ser somática (corregir un defecto genético en los órganos o tejidos afectados), o germinal (evitando su transmisión a los descendientes). No hay intervenciones de terapia germinal que estén siendo consideradas actualmente por científicos, médicos o compañías farmacéuticas. La clonación de humanos puede también referirse a clonación terapéutica o de individuos. Se han avanzado propuestas sugiriendo clonar individuos de gran capacidad intelectual o artística, o de virtud eminente. Tales propuestas utópicas son sumamente desafortunadas. No es posible clonar un individuo humano, aun si se clona su genoma. De genomas idénticos, desarrollados en contextos diferentes, familiares, sociales y culturales, pueden resultar individuos totalmente diferentes. Además, entran en juego consideraciones éticas, sociales y religiosas cuando se examina si una persona puede o debe ser clonada.
Formative E-Assessment and Behavioral Commitment of Students: Case of the Faculty of Science Ben M’sik
Authors: Chemsi Ghizlane , Sadiq Mounir , Radid Mohamed , Talbi Mohammed
Published: June 2019

Digital technology contributes to the development of new teaching practices and a new assessment culture [1,2,3]. Various studies [4,5] show that digital technology facilitates the formative assessment process, an assessment mode that favors the learner’s commitment and encourages the learner to adopt an efficient learning method [6]. All the more, the media coverage of this type of assessment generates a large number of indicators enabling to analyze the behavioral commitment of students in their learning process.

The objective of this study is to analyze the impact of formative E-assessment on the students’ behavioral commitment based on the digital traces of the students’ work, this traceability is considered a very important source permitting to find out about the students’ behavioral commitment. The assessment was achieved via the interactive Moodle platform, it was tested on a group of students from the Faculty of Sciences Ben M’sik in Casablanca, Morocco. The results of the experiment carried out for a period of two years (2015-2016 and 2017-2018) revealed that the majority of the students are committed to take the assessment test. We observed a real implication of the latter, where the action traces of the students in terms of participation and contribution could be collected and analyzed by the teacher for feedback purposes.
Impacts of Conceive-Design-Implement-Operate Knowledge and Skills for Innovative Capstone Project
Authors: Jambari Hanifah , Razali Nurul Amalin , Seth@Noh Nur Hazirah , Ahyan Nurul Aini Mohd , Pairan Mohamad Rasidi , Ahmad Jamilah , Osman Sharifah
Published: June 2019

Nowadays, the competitions among countries to recruit engineering students as workers do not focus on talents, but also on the reserve of it. The advancement of education in engineering field plays a big part in enhancing comprehensive domestic strength because the scientific revolution will contribute to important modifications of the industrial landscape. Therefore, Conceive-Design-Implement-Operate (CDIO) understanding and techniques are required for enhancing this field of education particularly for innovation of capstone project. Thus, this study was identified student knowledge and skills consist of teamwork, problem-solving, and communication skills of the CDIO in capstone project involved two faculties which are Faculty of Biosciences & Medical Engineering (FBME) and Faculty of Electrical Engineering (FKE) at Universiti Teknologi Malaysia (UTM). Our respondents consist of 28 and 30 of third-year students from FBME and FKE respectively. Besides, this study also was identified the importance of the CDIO approach in the innovative capstone project. The method that used was a quantitative survey by using 5 Likert scale questionnaires. The average mean for all research questions indicated that the majority of respondents agreed that the CDIO knowledge and skills in the capstone project are important in engineering education. Hence, the engineering students must possess not only the skills such as teamwork, problem-solving, and communication but also needs more knowledge that helps them to employability and adapt to real-world engineering problems.
Big Data Analytics for Improved Care Delivery in the Healthcare Industry
Authors: Thangarasu Gunasekar , Subramanian Kayalvizhi
Published: June 2019

The big data analytics plays a pivotal role in the field of healthcare services and research to facilitate better service to the patients. It has provided tools to accumulate, manage, analysis the structured and unstructured data produced by the healthcare systems. Recently the utilization of big data analytics has been increased in the healthcare industry for assisting the process of diagnosing diseases and care delivery. However, the adoption and research development of big data analysis in the healthcare industry is still slow down due to facing some fundamental problems inherent within the big data paradigm. In this study, addresses these problems which focus on the upcoming and promising areas of medical research and proposed a novel big data analytics approach using Apache Spark. The proposed approach will improve care delivery in the healthcare industry. Big data analytics can continually evaluate clinical data in order to improve the effective practices of physicians and improved patient care.
EEG Based Biometric Identification Using Correlation and MLPNN Models
Authors: Waili T , Johar Md Gapar Md , Sidek K. A. , Nor N. S. H. Mohd , Yaacob H. , Othman M.
Published: June 2019

This study investigates the capability of electroencephalogram (EEG) signals to be used for biometric identification. In the context of biometric, recently, researchers have been focusing more on biomedical signals to substitute the biometric modalities that are being used nowadays as the signals obtained from our bodies is considered more secure and privacy-compliant. The EEG signals of 6 subjects were collected where the subjects were required to undergo two baseline experiments which are, eyes open (EO) and eyes closed (EC). The signals were processed using a 2nd order Butterworth filter to eliminate the unwanted noise in the signals. Then, Daubechies (db8) wavelet was applied to the signals in the feature extraction stage and from there, Power Spectral Density (PSD) of alpha and beta waves was computed. Finally, the correlation model and Multilayer Perceptron Neural Network (MLPNN) was applied to classify the EEG signals of each subject.  Correlation model has yielded great significant difference of coefficient between autocorrelation and cross-correlation where it gives the coefficient value of 1 for autocorrelation and the coefficient value of less than 0.35 for cross-correlation. On the other hand, the MLPNN model gives an accuracy of 75.8% and 71.5% for classification during EO and EC baseline condition respectively. Therefore, these results support the usability of EEG signals in biometric recognition.
Effect of Processing Conditions on Bonding Strength at Al(Si)/Diamond Interfaces
Authors: Edtmaier Christian , Segl Jakob , Koos Robert , Schöbel Michael , Feldbaumer Christioph
Published: June 2019

Understanding thermos-physical properties of MMCs includes considering interfacial processes and interactions between the constituents in MMCs. In this context, interfacial bonding is of vital interest for a deeper understanding of composites. Neutron diffraction experiments on Al/diamond composites were performed and reconciled with their thermo-physical properties and quantification of interfacial carbides formation. To create different interfacial conditions both, the contact time during processing the MMCs by liquid metal infiltration and the nominal composition of the matrix were changed, thus creating different amounts of interfacial Al4C3 carbides. Neutron diffraction showed the increase in contact time and the addition of Si to Al both increase the bonding strength, although going with a significant decrease of the composite`s thermal conductivity.
Custom-Made Reinforcement Structures Made of Inorganic Fibers Challenges, Chances and Technical Approaches
Authors: Becker Marielies , Ficker Frank , Miksch Roxana , Olbrich Sabine
Published: June 2019

Ceramic fibers are just as glass and basalt member of the group of inorganic fibers. Like most types of inorganic fibers ceramic fibers have a high tear resistance but a limited flexibility. [1] Ceramic fibers are characterized by their extraordinary high temperature and chemical resistance. These properties make them interesting for different high technical applications, as they occur in aerospace, chemical-and energy technology. In this field, they are applied especially as a reinforcement component in composite materials. Not only the partially high material price, but although the typical brittleness of ceramic fibers bring huge problems during the textile production chain, which limits the availability of complex textile preforms in the market. Often, a radical revision of the machine and processing concept is necessary to enable an economical production process. The Application Center for Textile Fiber Ceramics TFK at Fraunhofer-Center for High Temperature Materials and Design HTL develops and modifies textile production processes to make them suitable for the special requirements of ceramic fibers. One and multilayer woven fabrics, braids and tape structures for the winding process have already been successfully implemented. A further development complex is the intensive investigation of three-dimensional textile reinforcement structures. Regarding the high material costs, these research activities are very important. If the textile reinforcement is placed only where needed, the amount of used fiber material can be reduced significantly.
One-Sided Resistance Spot Welding of Plastic-Metal Hybrid Joints - Characterization of the Joining Zone
Authors: Szallies Konstantin , Friedmann Michael , Bielenin Martin , Bergmann Jean Pierre
Published: June 2019

Polymer-metal-hybrid components show a high potential regarding to lightweight applications. In particular, due to their fundamental differences in chemical and physical properties, new approaches must be developed for common industrial joining processes. In this study a new approach in order to characterize the joining zone formation for thermal direct joining based on resistance spot welding is reported. The feasibility of joining in half-section set-up using a coaxial electrode arrangement was investigated. The impact of the welding parameters on the joining zone formation was investigated. The parameters influencing the melting layer formation were pointed out.
Influence of Welding Temperature and Weathering on Inductive Welded Hybrid Joints Made of Steel and TP-FRPC
Authors: Weidmann Stefan , Mitschang Peter
Published: June 2019

Aim of this study is to investigate the influence of welding temperature and weathering on bond strength of induction welded hybrid joints made of steel and thermoplastic fiber reinforced polymer composites (TP-FRPC). The used TP-FRPC are continuous glass fiber reinforced-polyamide 6 (PA6), -polypropylene (PP), -polycarbonate (PC) and-polyphenylenesulfide (PPS). The metal sheets are mild steel (1.0338 and 1.0330). The surface pretreatments of the metal sheets are either laser structuring in line pattern, perpendicular to the load direction, or two different types of functional coating adhesives (Köratac HL 400 and Köratac HL 403) currently used in coil-coating processes. First the process parameters were optimized for each material combination by investigating the bond strength at different welding temperatures. In a second step, for each material combination, specimens were welded using the determined welding temperatures with the highest bond strength in order to investigate the influence of weathering on hybrid joints. Therefore the cataplasma test (DIN EN 13523-27: 2009) as well as alternating climatic change (BMW PR 308.2) were used.
Evaluation of DOPO and Nano-Silica Modified Epoxy Resin Systems as Low Viscous, Flame Retardant Additives for Infusion and Injection Processing of Carbon Fiber Reinforced Plastics
Authors: Häublein Markus , Peter Karin , Brückner Alexander , Altstädt Volker
Published: June 2019

In the present study, a low viscous (complex viscosity between 200 to 500 mPas at 60 °C), flame retardant epoxy resin formulation is prepared and transferred to the carbon fiber reinforced plastic (CFRP) laminate using resin transfer molding (RTM) method. For the laminate production, a 12k carbon fiber fabric with an areal weight of 400 g/m2 is used to achieve a fiber volume content of approximately 60 vol % carbon fibers. Subsequently the unmodified laminate is produced, varying carbon fiber volume content to study its effect on flame retardant properties. As additives, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) modified epoxy resin and nanosilica particles delivered in an epoxy novolac masterbatch are added to the neat novolac resin system. The mixture is cured with isophorone diamine (IPDA) and polyetheramine hardener blend, resulting in a glass transition temperature of 104 °C for the unmodified laminate. Flame retardant properties of the materials are tested using cone calorimeter and thermal gravimetrical analysis. In addition, the mechanical behavior of the systems is evaluated via three-point bending method in static and dynamical loadings. In order to get deeper information on the resulting flame retardant mechanisms of the additives, the residual cone calorimeter char is analyzed with scanning electron microscopy, indicating the different flame retardant mechanisms of phosphorous and silica as well as the combination of both additives.
Deflection Sheaves for Elevator Application in Lightweight Design
Authors: Gerlach Hendrik , Müller Hartwig , Klingelhöfer Marcus , Ziesch Roland , Katkowski Mikolaj , Spieler Mirko , Nendel Wolfgang , Kroll Lothar , Bochmann Felix
Published: June 2019

Current elevators are mostly designed as rope-dependent elevators. Main components in the roping system are the deflection sheaves which are conventional manufactured of grey cast iron. Due to the high weight of cast iron sheaves there is a high potential for reducing mass, especially when regarding aspects of effort, safety and ergonomics while assembly and maintenance in the elevator shaft. Within the framework of a R&D co-operation the Chemnitz University of Technology and the AMB Oberlungwitz GmbH developed a fibre-reinforced plastic sheave that comply with the requirements of lightweight design. The technological basic approach to realize that development is compression molding of glass-mat-reinforced thermoplastics (GMT). The project includes the whole development-chain, consisting of part design, tool design, process chain arrangement, parameter studies as well as validation of specimen. In the course of the project appeared a high potential for improvement of the part properties by alternative design solutions. In this context current activities are focused on multi material design methods such as combining GMT with other thermoplastic prepregs. In this manner it is possible to equip every local area with the specific properties that are required. For example the ribs of the sheave, that receive highest values of stress, can be made of materials with continuous-fibre-reinforcement while the basic part body consists of GMT, which is long-fibre-reinforced. This method also enables to avoid process influenced effects like the segregation of the fibre-matrix distribution in GMT. Additionally the input of different materials offers chances to inlay non-preheated prepreg blanks into the compression mould, so that the amount of the preheated material volume can be reduced. In this way cycle times and also lost of temperature due to transfer times of the heated blanks to the mould can be reduced.
Tailor Made Hybrid Laminates Based on UD-Tapes - A Way to Efficient Thermoplastic Components
Authors: Habla Franz , Kropka M. , Muehlbacher M. , Neumeyer T. , Altstädt Volker
Published: June 2019

In this study, the quality of pre-consolidation of a PA6 based glass/carbon hybrid and a glass mono-material UD-tape laminate has been analyzed and the influence of the pre-consolidation step on flexural properties of end-consolidated laminates was determined. For this reason, three different pre-consolidation qualities were mechanically and optically analyzed. The investigations show that the quality of pre-consolidation is not critical for mono-material lay-ups considered in this work. However, the pre-consolidation step has a significant effect on the flexural properties of the hybrid-material laminate presented in this work. The flexural modulus is increased by more than 25 % and the flexural strength up to 9 % due to better welding of the distinct layers. Additionally, the influence of carbon fiber share on the flexural modulus of the UD hybrid-material was examined. It could be recognized that the flexural modulus can be increased up to 171 % by the exchange of glass with carbon fiber layers with a sandwich stacking compared to glass mono-material with constant thickness.
Efficient Multiscale Methods for Viscoelasticity and Fatigue of Short Fiber-Reinforced Polymers
Authors: Welschinger Fabian , Köbler Jonathan , Andrä Heiko , Müller Ralf , Schneider Matti , Staub Sarah
Published: June 2019

To predict the nonlinear mechanical behavior of components made of short fiber-reinforced plastics (SFRP) under long term and cyclic loading, coupled process and component simulations are required. The injection molding process leads to locally varying fiber orientations within the component. This varying microstructure [1] significantly influences the viscoelastic and fatigue behavior. The interaction between the microstructure [2] and the nonlinear macroscopic properties is resolved by a coupled fast Fourier transformation and finite element two-scale method (FFT-FEM), where the fiber orientation tensor is obtained by analyzing μCT images or by the corresponding process simulation. The aim of this work is to reduce the numerical costs of such a multiscale method. In a first step, the highly efficient micro-scale solver FeelMath [3,4] using an FFT-based preconditioner is presented. Afterwards, a numerical scheme based on a precomputed database trained with FeelMath simulations on the microscale and a model order reduction algorithm, is discussed. The combination of these ideas reduces the numerical effort, such that the method is applicable for industrial problems. Comparative studies of the fully coupled and reduced model document the high accuracy of this approach. The overall performance of this methodology is demonstrated by three-dimensional, industrial applications.
Assessment of Secondary Fiber Print-Through Effects on Class-A CFRP Parts Produced with Highly Cost Efficient Processes
Authors: Metzger Dominik , Meeß Joachim , Heine Michael , Henke Thomas
Published: June 2019

Cost-optimized materials and processes are the key to high-performance components at attractive production costs. This study shows that non crimp fabrics (NCF) used as inner layers of high performance Class-A cfrp parts can lead to unwanted print-through effects on Class-A composite surfaces, even though they are not the surface layer. This surface distortion that is expressed in scattered lines in the direction of inner NCF layers can lead to high reject rates and is normally first noticed in the painted state. The presented methodology is able to quantify this secondaryprint-through effect for cured composites as well as for the dry textile intermediates. The surface can be measured with conventional measuring techniques, such as laser triangulation or interferometers, and characterized with the standardized values Sz and Sz25. The results show that the visible and measurable more uneven surface of a 50k biaxial NCF leads to significantly higher Sz and Sz25 values in the dry textile and the cured component. Also the regularity of the measured textiles can be detected by determining the variation of different areas of a 800 by 800mm sized sample. The presented methodology has the potential to optimize the incoming goods inspection of high volume Class-A composite manufacturers, as well as the requirement-orientated and cost-efficient development of textile intermediates by suppliers.
Novel Approach for the Lifetime Prediction of Composite Materials under Static Loads
Authors: Gloggnitzer Stefan , Pilz Gerald , Schneider Christian , Pinter Gerald
Published: June 2019

Composite materials in structural applications that are subjected to static loads for several decades tend to change material performance over their lifetime. Classical creep tests with constant static loading are quite simple tests with low demands on the test equipment. Unfortunately, these tests require uneconomically long test times, which is why a shortening of the test times with various accelerated approaches is being researched. Within this work two approaches for reduction of the testing time were investigated. On the one hand a fatigue test with the variation of R-ratio and following extrapolation to an R-ratio of 1 was done. On the other hand a Stress Rate Accelerated Creep Rupture Test (SRCR) was developed, where a defined initial stress σi is applied at the beginning of the loading process, followed by an increase load with a constant rate instead of the static stress segment of the classic creep rupture tests. Changing the load rate in several individual tests leads to stress rate-dependent fracture strengths with associated fracture times, which allows extrapolation to a fracture time at a load rate of zero. In particular, the approach of the SRCR offers great potential for greatly reducing test times with an acceptable prediction quality.
Efficient Process Chain for Processing Natural Fiber Reinforced Thermoplastics
Authors: Gortner Florian , Mitschang Peter , Neu Wiebke , Dittrich Andreas , Schmidt Lisa , Braun Ingo , Zhao Li , Ziesak Alexandra , Schäfer Volker
Published: June 2019

Natural fiber reinforced polymer composites (NFRPC) are conventionally processed in compression molding process to shell-shaped components, which are mostly used in automotive industry. Therefore, natural fibers (NF) and polypropylene (PP) as matrix system are processed to a thermoplastic organic sheet. Organic sheets are heated in a contact heating press to temperatures above melting temperature of the matrix and then transferred to a forming press. In this paper, Acrodur®Power 2750 X (AP) is used as an alternative to PP. This thermoplastic matrix system enables an increase of fiber content to 75 wt.-% in NFRPC. Furthermore, infrared radiation (IR) with adapted wavelength was used as an alternative to conventional contact heating. To improve the heating behavior of NF/AP infrared and heat transfer additives were used. By adding heat transfer additives and using IR heating with adjusted wavelength, both heating time can be reduced from 45 seconds (NF/PP) to 25 seconds (NF/AP) and a contact heating press can omitted.
Influence of the Process Parameters on the Penetration Depth of the Reinforcing Phase during Composite Peening for the Production of Functionally Graded Metal Matrix Composites
Authors: Seitz Michael , Weidenmann Kay André
Published: June 2019

Composite peening describes a modified process based on micro shot peening. This process allows the controlled penetration of ceramic particles into areas of metallic matrix materials close to the surface layer. Composite material produced by composite peening promises a high application potential in the fields of lightweight, wear-resistant and durable materials. The use of ceramic reinforcing particles is expected to significantly improve thermal stability compared to conventional surface hardening processes. In addition, composite peening offers the possibility of cost-effectively reinforcing components and can even be applied subsequently in highly stressed surface layers. The material combination selected for this study was technically pure aluminum as model and matrix material and alumina as abrasive respectively reinforcement material. The influence on the particle density and the particle gradient was achieved by varying the process parameters, such as the process temperature and the peening pressure. A maximum penetration depth of almost 30 μm could be observed at high homologous temperatures. In light and scanning electron microscopy it was observed that the ceramic particles might break on impact with the surface of the blasting material. This causes a drastic reduction of the particle size, which initially had a size of 10 μm. This reduction of particle size promises advantages, particularly with cyclic loads.
Refined New Technology and Application of Phosphate Rock Associated Iodine
Authors: Song Xi Gao , Zhang Jie
Published: June 2019

Iodine is a world of scarce resources, and its characteristic is low yield, high price, wide uses. Production of iodine is≦800 t/a in our country, but demand of iodine is above 4000 t/a, so demand differences is big, about 80% of the iodine is importsed from countries such as Chile, Japan, turkmenistan[1]. At present iodine in our country mainly rely on extracting from kelp, but iodine yields are low,owing to limited algae production, low technology, large waste of resources and high operating cost factors, it is difficult to meet the basic requirements of iodine in our country. However, phosphate rock in our country contains considerable associated iodine, so much attention are given to development of associated iodine resources and comprehensive utilization of phosphate rock.
Removal of Trichloroethylene by Corona Radical Injection
Authors: Li Zhan Guo , Zhao Hong Jie
Published: June 2019

The removal of trichloroethylene (TCE) by corona discharge plasma was investigated. The influences of initial concentration, gas flow rate, injection of water vapor and ozone (O3) on removal efficiency were discussed. The results show that removal efficiency reduces with the initial concentration and gas flow rate increasing. A proper quantity of water vapor injection can improve the removal efficiency, but which is not always increased, due to the electronegative characteristic of water molecule. The maximum removal efficiency of 90.7% can be obtained in wet air flow with relative humidity of 70.6%. The removal efficiency increases obviously with O3 injection. The decomposition products are 2,2-Dichloroacetyl chloride (CHCl2COCl), carbonyl chloride (COCl2), hydrogen chloride (HCl) and carbon dioxide (CO2), based on which the decomposition mechanism is discussed. The oxygen chain reaction is the primary decomposition mechanism, and high energy electrons and active oxygen species play a leading role in the decomposition process. Therefore, removal efficiency of TCE can be improved greatly when water vapor and O3 is injected.
Effect of Aramid Fiber Surface State on Properties of Epoxy Resin Composites
Authors: Qiu Man Shi , Pan Ze Hua , Zhang Yuan Yuan , Li Yong Lan , Gao Nai Kui , Jin Hai Yun
Published: June 2019

The surface state of aramid fiber was modified by coupling agent to characterize the change of the state. The fiber / epoxy resin composites were prepared to study the mechanical and electrical properties and the internal mechanism of how different surface states affect. The results show that, after the treatment with the coupling agent, the surface roughness of the aramid fiber is increased，and the content of Si on the surface reach 5.8%, thus the surface activity is enhanced. At the same time, the treatment makes the properties of composites further improved. When the filling amount of aramid fiber reaches 30 strands, the tensile strength increase by 38.4% due to the coupling agent. In the test of two-layer samples, the breakdown field strength of the composites before and after treatment with coupling agent increased by 15.9% and 20.2%, respectively.Key words: aramid fiber; coupling agent; surface state; mechanical properties; electrical properties
Effect of Calcined-Bauxite Quality and Secondary Mullitization Reaction on Firing and Properties of Ceramic Plates
Authors: Xiao Li Biao , Hua Xiao Qing , Xue Qun Hu
Published: June 2019

Addition of different types of calcined bauxites to the ceramic plate formulation was performed to study effects on the firing and properties of the resulting ceramic plates. The physical and chemical characteristics, high-temperature reaction degree, thermochemical behavior, mineral composition, and microstructure of the calcined bauxites were analyzed. The results showed that lightly calcined bauxite could minimize the linear shrinkage rate. However, incomplete high-temperature secondary mullitization reaction could inhibit completion of product sintering and result in a loose microstructure, high water absorption index, and low modulus of rupture. Application of GAL-85 high-temperature calcined bauxite yielded a product with good sintering performance and low water absorption; increased amounts of mullite reinforcement phase also increased the strength of the plate. The degree of secondary mullitization was the main factor affecting the performance of the ceramic plate.
Luminous Efficiency of Pd-Doped Ag-Alloy Wire Bonded LED Package after Reliability Tests
Authors: Yuan Jui Hung , Chuang Tung Han
Published: June 2019

In this study, binary Ag-alloy wires were doped with different Pd concentrations, and each wire was encapsulated in an LED package. The initial optical characteristics were tested, and reliability was tested with the high temperature storage life (HTSL), high temperature operating life (HTOL) and wet high temperature operating life (WHTOL). The luminous efficiency of the Ag-alloy wire LED package was about 2% higher than that of the Au wire package, but the addition of 6% Pd to the Ag-alloy wire decreased the luminous efficiency to close to that of the Au-wire LED package. This was due to the high reflectivity of silver in the blue wavelength region, as compared to the low reflectivity of palladium. After 1,000 hours of HTOL and WHTOL, the results showed that the performance of luminous flux maintenance increased with increasing Pd content, indicating that Ag-alloy wires doped with a sufficient amount of Pd can inhibit degradation due to oxidation reaction and thermal and humidity aging. Therefore, binary Ag-Pd alloy wires produced with specific drawing and annealing processes are suitable for mid-power white light LEDs in lighting applications.
Technical Analysis and Overview of the Application of Artificial Dielectric Materials in the Form of Photonic Crystal Cavity with Resonance in Dirac Leaky-Wave Antennas
Authors: Walia Ritu , Chopra Kamal Nain
Published: June 2019

Application of Artificial Dielectric Materials in the form of Photonic crystal cavity with resonance in Dirac leaky-wave Antennas. The system investigated is a Photonic crystal cavity for the radiation properties of an antenna formed by a combination of a monopole radiation source and a cavity by a dielectric layer-by-layer 3D photonic crystal. The Photonic crystal cavity under study is working at resonance, since a high directivity, and a high power enhancement are obtainable at the resonant frequency of the cavity.In addition, an approach based on (i) Hughen's wavelets and (ii) the components of the incident Intensity after transmission through the system, is suggested for optimizing the performance of the optical antennas. Also, it has been discussed that the Optical antenna fabricated by Dielectric material - Photonic crystal is a better alternative to a conventional focusing lens, in Nanoscopy, in order to concentrate the laser radiation to dimensions smaller than the diffraction limit.
Fabrication of PMIA/fBN Dielectric Composite with Enhanced Breakdown Strength and Thermal Conductivity
Authors: Duan Guang Yu , Hu Zu Ming
Published: June 2019

A high-temperature poly (m-phenyleneisophthalamide) (PMIA) dielectric composite was successfully manufactured with functionalized BN (fBN) fillers. Due to effective modification by KH-550, fBN particles evenly dispersed in PMIA matrix. The dielectric property, breakdown strength and thermal conductivity of PMIA/fBN dielectric composite were researched. The consequences indicate that fBN fillers can not only decrease the dielectric loss but also enhance the breakdown strength of PMIA/fBN dielectric composites. Furthermore, owing to the generated heat transfer pathways by fBN particles, the thermal conductivities improved from 0.23 W·m-1·K-1 of fBN-0 to 0.86 W·m-1·K-1 of fBN-30, demonstrating a significant improvement. These results present a novel method for fabricating high-temperature PMIA/fBN dielectric composites with improved breakdown strength and thermal conductivity.
MnO2/HF/HNO3/H2O System for High-Performance Texturization on Multi-Crystalline Silicon
Authors: Liu Huan , Zhao Lei , Diao Hong Wei , Wang Wen Jing
Published: June 2019

It was found that the addition of MnO2 particles into the HF/HNO3/H2O system could significantly improve the texturization etching performance on multi-crystalline silicon (mc-Si) wafer. For a wide component ratio range of HF/HNO3/H2O from HF-rich to HNO3-rich, by optimizing the MnO2 usage and the etching time, the addition of MnO2 particles always reduced the texture reflectance greatly. Low weighted average surface reflectance (Ra) for the AM1.5G sun spectrum in the wavelength range of 380–1100 nm was achieved on both the slurry wire sliced (SWS) mc-Si and the diamond wire sliced (DWS) mc-Si. Due to its excellent effect and simple processing, the MnO2/HF/HNO3/H2O etching system can be expected as a candidate for high-performance texturization on mc-Si wafer, especially on DWS mc-Si wafer.