bluuebunny/crossref_metadata_2025 huggingface dataset:
Reseña: Cruce de miradas: Nuevas aproximaciones al libro-álbum
Authors: Munita Jordán Felipe
Published: November 2018

ResumenCruce de miradas: Nuevas aproximaciones al libro-álbum revisa el estado actual de la investigación internacional sobre álbumes ilustrados, con un total de dieciséis artículos escritos por académicos e investigadores de reconocida trayectoria en este campo. El volumen se articula en 3 líneas temáticas: los libros-álbum y la cultura actual, la construcción narrativa del álbum y los retos cognitivos y la búsqueda de significado en la lectura de álbumes.  ResumCruce de miradas: Nuevas aproximaciones al libro-álbum  revisa l'estat actual de la recerca internacional sobre àlbums il?lustrats, amb un total de setze articles escrits per acadèmics i investigadors de reconeguda trajectòria en aquest camp. El volum s'articula en 3 línies temàtiques: els llibres- àlbum i la cultura actual, la construcció narrativa de l'àlbum i els reptes cognitius i la recerca de significat en la lectura d'àlbums.RésuméCruce de miradas: Nuevas aproximaciones al libro-álbum en revue l'état actuel de la recherche internationale sur les livres d'images, avec un total de seize articles écrits par des professeurs et des chercheurs de renom dans ce domaine. Le volume est divisé en trois thèmes: l'album et la culture moderne, la construction narrative de l'album et des difficultés cognitives et la recherche de sens dans la lecture d'albums.
No sé qué day: Code-switching and code-mixing in a plurilingual family living in Catalonia
Authors: Simon Auerbach Jill
Published: November 2018

This study analyzes the unique plurilingual (Catalan, Spanish and English) speech of a family living in Catalonia in order to understand the  variety of forms in which linguistic multicompetence is made manifest in their dialogues.. Factors that were found to influence code-switching and code-mixing in dialogues among family members include: the context of the conversation, the expression of distinct discursive voices, the affective consequences of employing the dominant or non-dominant language of the interlocutor, the ingrained nature of discourse markers, resistance to changing the names of academic concepts or courses, and the desire to creatively combine elements of distinct language systems to suit the expressive needs of the speaker. An argument is made in favor of a distinction being made between linguistic variety and communicative code as well as for a user-based, pragmatic view of language knowledge.
Grande y gruesa pequeña literatura
Authors: Hernández Ranz Olalla
Published: November 2018

A partir del estudio de BIG FAT LITTLE LIT, una recopilación de historietas de diferentes autores concebidas para niños y editada en Estados Unidos por los expertos Francoise Mouly y Art Spiegelman, la presente investigación reflexiona sobre la forma en que se expresa el cómic infantil a un nivel intratextual. Inscrita dentro del campo de estudio de la narratología, el trabajo analiza el tiempo narrativo de historia y discurso de la historieta infantil, con el objetivo de obtener conclusiones que abran nuevas vías de investigación que incentiven la creación de este medio de expresión en nuestro país.
La ambigüedad de significado en el álbum y su lector implícito
Authors: Turrión Penelas Celia
Published: November 2018

La ambigüedad de significado es, de entre las complicaciones narrativas asociadas a la producción literaria contemporánea, una de las de más tardía introducción en el sistema de la literatura infantil y que desafía radicalmente las convenciones asociadas a los libros para niños. La ambigüedad demanda un mayor esfuerzo interpretativo por parte del lector, el cual debe activar sus recursos de generación de significados para comprender el libro. Este estudio trata la presencia de la ambigüedad en los libros para niños como un posible criterio de calidad, siempre y cuando vaya acompañada de una estrategia de cooperación interpretativa. El artículo aborda la ambigüedad de significado en un tipo de libro concreto, idóneo para la innovación y que permite formas narrativas más flexibles y mayores complicaciones estructurales: el álbum ilustrado, y lo hace tomando como ejemplo el análisis de El Túnel de Browne.
Entretien: Les approches plurielles dans l'enseignement des langues: un entretien avec Michel Candelier
Authors: Pascual Calvo Xavier
Published: November 2018

Michel Candelier est professeur à Université du Maine, Le Mans, France. Il est coordinateur d’un projet intitulé CARAP "Cadre de référence pour les approches plurielles", mené dans le cadre du programme « Valoriser les professionnels en langues » du Centre européen pour les langues vivantes (CELV) et a publié de nombreux articles à propos de l’enseignement à l’aide des approches plurielles visant à développer des compétences plurilingues et interculturelles chez les apprenants de toutes disciplines.
La función de los gestos durante la planificación del juego en el jardín de infantes
Authors: Migdalek Maia Julieta , Rosemberg Celia Renata
Published: November 2018

Des de la teoria sociocultural del desenvolupament humà (Vigotsky, 2009; Bruner, 1986, 1989) la interacció situada s’entén com l’espai privilegiat pel desenvolupament del llenguatge. Tot partint del fet que en la interacció les formes lingüístiques estan imbricades amb altres sistemes semiòtics, en aquest treball s’analitza l'ús dels gestos de la mestra en la planificació del joc en una sala de parvulari (4 anys). L’anàlisi segueix una lògica qualitativa que articula el Mètode Comparatiu Constant (Strauss y Corbin, 1991) amb l'ús heurístic de conceptes de l’Anàlisi de la Conversa (Goodwin 2000; Tusón, 1995), el microanàlisi discursiu (Gumperz, 1982) i els estudis de la gestualitat (McNeill, 1985, 1992).Se ha trobat que els gestos assenyalen els aspectes centrals de la consigna i poden, en aquest sentit col·laborar en la comprensió per part dels nens de referents abstractes, vocabulari i les regles de joc.
Editor’s Note
Authors: Dooly Melinda
Published: November 2018

This volume has an interesting variety of articles, which at first glance, may not seem to have much in common. However, taking a deeper look at the contents of the texts, several common nexus emerge, above all the feeling that we are moving into a new era of globalization that requires interrogation of how we teach language and literature ...
Enseñar y aprender conocimientos gramaticales alrededor de la frase: Una experiencia a ciclo inicial
Authors: Méndez i Navarro Anna
Published: November 2018

Con el objectivo de dar apoyo a los centros en el tratamiento de las lenguas en el contexto actual, el Departamento de Enseñanza de la Generalitat de Catalunya promueve desde el curso 2007-2008 el nuevo Proyecto de actualización de la metodología de Inmersión Lingüística. El proyecto consiste básicamente en facilitar a las escuelas integrantes los recursos formativos necesarios para lograr este reto con éxito. Una de las actividades de las diversas acciones formativas se complementa con unas sesiones de modelización en que formadoras del Departamento ejemplifican como desarrollar en las aulas las estrategias y los contenidos abordados en la formación. En este contexto el presente artículo se propone analizar una de las sesiones de modelización sobre la enseñanza de conocimientos alrededor de la frase en el Ciclo Inicial. Un análisis que permite destacar algunas cuestiones a optimizar en estas sesiones.
Els perfils de pràctiques docents i el sistema de creences: un estudi de cas de dues mestres de parvulari
Authors: Pérez-Peitx Mireia
Published: November 2018

The aim of this article is to explore the belief system about teaching and learning of writing and reading of two preschool teachers of a public school located in Barcelona, and to relate it with their practical activity in the classroom. From an ethnographic approach, data collected from interviews and participant observation was analyzed to allocate each teacher in one of the three possible profiles defined by González, Buisán and Sánchez (2009) and to have a better understanding of which beliefs stand each profile defined in the above mentioned study.
School and Immigration: Welcoming Literature
Authors: Colomer Martínez Teresa
Published: November 2018

S'exposen els avantatges de la literatura perquè els infants inouvinguts elaborin el seu procés de trànsit, conjuminin les seves identitats i estableixin ponts entre les seves capacitats lectores i comunicatives i les exigències escolars. S'ofereixen criteris sobre els llibres adequats perquè siguin compartits amb els seus companys d'aula, els ajudin a incorporar-se al treball escolar i propiciïn una educació intercultural comuna. S'indiquen activitats que resulten especialment indicades en les aules, com les basades en l'oralitat i la interpretació de narracions amb un fort component visual. Es destaca la guia del docent en les discussions en grup com una bastida lingüística i interpretativa molt convenient, tant per als nouvinguts, com per a l'educació lectora i literària de tots els alumnes.
Creativity and Narrative Writing in L2 Classrooms: Comparing Individual and Paired Task Performance
Authors: Zabihi Reza , Rezazadeh Mohsen , Vahid Dastjerdi Hossein
Published: November 2018

El estudio presentado en este artículo examina el rol de creatividad de los estudiantes cuando se escribe individualmente y colaborativamente en el L2. A este fin, una muestra de 92 estudiantes de lengua inglesa (nivel intermedio) de la universidad de Isfahán, Irán, participaron en este estudio. Los participantes fueron divididos en dos grupos: un grupo trabajaba individualmente y el otro grupo trabajaba colaborativamente. Se mida la creatividad usando el Test Torrance (Abreviado) para Adultos (ATTA) para observar la fluidez, elaboración, flexibilidad, y originalidad. También el estudio mida la complejidad, exactitud, y fluidez (CEF) de la ejecución de una tarea donde los estudiantes narran un relato basado en una imagen. Los resultados mostraron (a) importantes ventajas en lo que se refiere a (CEF) en cuanto se refiere a escrituras colaborativas en comparación con aquellos textos hechos individualmente; (b) correlaciones importantes, entre la creatividad y la fluidez de los estudiantes; y (c) una relación negativa entre la originalidad y la creativa tanto en la ejecución de la tarea por parejas como ejecución individual.
¿Por qué una tesis sobre la muerte? Entrevista con Txabi Arnal Gil
Authors: Olid Báez Isabel
Published: November 2018

Txabi Arnal Gil is a well-known writer for children and youngsters, whose books have received several awards. He also teaches literature at the Faculty of Education at Escuela Universitaria de Magisterio de Vitoria-Gasteiz, País Vasco-Euskal Herriko Unibertsitatea. In this interview, he tells us about his PhD Dissertation, El tratamiento de la muerte en el álbum infantil. Obras publicadas en castellano (1980-2008), written within the PhD Programme “Psicodidáctica de la Educación y Didácticas Específicas” in the Department of Language and Literature Didactics of the University of the Basque Country / Euskal Herriko Unibertsitatea, which deals with the treatment of death in children’s books.
An Interview with Ohio University Associate Professor of CALL Greg Kessler
Authors: Antoniadou Victoria
Published: November 2018

La Enseñanza de Lenguas Asistida por Ordenador (CALL por sus siglas en ingles) es un amplio campo de investigación que actualmente está siendo indagado con interés en el área de idiomas. Victoria Antoniadou de Bellaterra Journal of Teaching & Learning Language & Literature, tuvo el placer y privilegio de entrevistar en línea a un pionero en este campo, el Dr. Greg Kessler, profesor asociado de Enseñanza de Lenguas Asistida por Ordenador en el Departamento de Lingüística de la Universidad de Ohio. Su pasión y conocimiento empírico en este campo ha generado una conversación rica y profunda sobre el potencial de la enseñanza asistida por ordenador y formación de profesorado de lenguas extranjeras en la pedagogía contemporánea. El Dr. Kessler compartió sus experiencias de investigación de programas de formación docente en los EE.UU. y el mundo, así como su conocimiento acerca de las investigaciones que se realizan actualmente para explorar y aprovechar el enorme potencial que este campo tiene que ofrecer a la innovación pedagógica.
Using Skype in a Primary Class: A Case Study
Authors: Cuestas Aida
Published: November 2018

Es difícil negar el importante rol de las nuevas tecnologías para comunicarse en el mundo globalizado en el que vivimos. Por esta razón, los discentes deberían tener este hecho en cuenta y dejar a los niños y niñas construir sus conocimientos a través del aprendizaje del funcionamiento de estas herramientas. En el contexto de TEFL, la comunicación a través de los ordenadores puede convertirse en una herramienta poderosa para el aprendizaje ya que da significado y realidad a las prácticas y actividades didácticas. Esta investigación, arraigada a la teoría sociocultural, muestra la implementación de una actividad interaccional a través del uso de Skype y aporta datos que refuerzan el potencial de los recursos digitales para el aprendizaje de una lengua extranjera, ya que estos pueden funcionar como una herramienta mediadora, que incrementa la motivación del alumnado y los anima a interactuar entre ellos.
Beliefs and Practices towards Teaching and Learning Grammar: A Multicase Study
Authors: Ferreira Patrícia
Published: November 2018

This text presents a multi-case study focused on 5th and 6th grades’ (10 - 12 years-old students) teachers’ beliefs and practices towards the process of teaching and learning grammar. Current practices of grammar instruction are connected to prescriptive approaches, outdated, disconnected from linguistic theory, and ineffective at improving communicative skills. Research has revealed that to promote real changes in practices it is important to act upon all the dimensions of teachers’ professional knowledge, including tacit phenomena, like beliefs, by means of professional training and development. The recent modification of the Portuguese Language curriculum reflects a new paradigm in grammar teaching, based upon a constructivist approach. Therefore, it is relevant to know how teachers implement it and how what they think about teaching grammar affects their practices.Data analysis revealed inconsistencies between beliefs and practices, leading to the conclusion that teachers have difficulties facing the required adjustment to the emerging paradigm.
Interacción en el aula y formación inicial del profesorado: Hacia la construcción compartida del conocimiento educativo
Authors: García Iglesias Victoria , Fabregat Barrios Santiago
Published: November 2018

The aim of this article is to show the importance of creating class sequences that encourage student interaction through the shared construction of the aim of knowledge and promoting exploratory talk in the context of teacher training. The mechanisms that help educational learning construction among equals, creating cooperative learning areas, are shown through the conversational analysis of two segments of interaction from different educational levels involved in initial teacher training. It proposes new teaching styles for teachers based on a sociocultural learning concept, which can easily be incorporated into their future professional teaching practice in the classroom.
Reseña: School-based research. A guide for education students, coordinado por Elaine Wilson
Authors: Mussano Claudia
Published: November 2018

Aquest llibre va dirigit a professors en actiu i/o estudiants de màster que desitgin realitzar una recerca a l’aula i que necessitin un manual que els acompanyi en el seu procés de recerca, des de la formulació de les preguntes de recerca fins a la redacció final del treball. Concretament, el text tracta el tema de com recollir la bibliografía i construir el marc teòric, exposa els problemes ètics que poden aparèixer, explica com recollir i analitzar les dades, proporciona consells per al procés d’escriptura del treball, il·lustra les diferències entre els enfocaments qualitatius i els quantitatius, defineix que és una recerca-acció, un estudi de cas i un grounded theory method i, finalment, descriu els paradigmes filosòfics que recolzen cada investigació. El volum, que destaca per la seva claredat i la seva accessibilitat, ofereix, a més a més, exemples concrets extrets de recerques ja publicades, així com esquemes i resums per explicar els continguts més complexos.
Lettre de l'éditrice
Authors: Dooly Melinda
Published: November 2018

Los volúmenes que la nuestra revista publica al inicio de cada curso académico tienen por costumbre presentar el trabajo de un investigador del departamento que la edita. En este caso, el autor invitado es el doctor Xavier Fontich Vicens. Su artículo trata un tema que siempre presenta retos al profesorado: ¿Cómo ha de enseñarse la gramática? ...
Teachers’ First Language Use in Second Language Learning Classroom Context: A Questionnaire-based Study
Authors: Mohebbi Hassan , Alavi Sayyed Mohammad
Published: November 2018

Recently the issue of having recourse to second language (L2) learners’ first language (L1) in second language acquisition (SLA) is receiving a great amount of attention in SLA research. There has been a great deal of claims and counter-claims with respect to L1 use in L2 learning. The findings of L2 research to date cast doubt on the rationales of proponents of exclusive use of L2.  Researchers and practitioners who have observed L2 classrooms have identified different functions of L1 in L2 learning. Drawing on previous research as a framework, the present study investigates teachers’ beliefs and perceptions about L1 use in English-as-a-foreign language (EFL) learning contexts. To this end, seventy-two L2 teachers volunteered to fill in a questionnaire which probed into their beliefs and perceptions about employing learners’ L1 (Persian) in L2 (English) learning. The data obtained revealed that the L2 teachers used L1 mainly to provide feedback, teach new vocabulary, explain grammar, build rapport, manage the class, give individual help to learners, and save time in lengthy task explanations. However, in contrast to the L2 studies to date in this field, the teachers expressed that they never fall back on learners’ L1 to explain instructions for assignments or projects. The findings might have significant implications for language teachers, in particular in EFL contexts, regarding the facilitative effects of L1 use on L2 learning. The pedagogical implications of the study are explained in detail.
L’ensenyament de l’espai geogràfic en una aula d’anglès de primària
Authors: Anguera Cerarols Carles
Published: November 2018

El treball per competències posa l’èmfasi en què l’aprenentatge ha de suposar que l’alumnat sigui capaç dominar els recursos que el permetin actuar d’una forma eficaç i raonada en la societat actual.  L’assoliment i adquisició d’aquestes competències implica conèixer, a nivell oral i escrit, aquelles llengües, que són imprescindibles per poder resoldre les situacions amb què les persones ens podem trobar en el desenvolupament de les nostres activitats socials com a ciutadans. El projecte PADS parteix d’aquestes premisses i presenta un treball que ha permès, entre d’altres coses, una aproximació a l’aprenentatge l’espai geogràfic en una aula d’anglès a primer curs de primària. Per fer-ho possible, s’ha recoltzat en metodologies com el treball per projectes i la telecol·laboració, fet que ha permès que l’aprenentatge hagi estat significatiu, funcional, transdisciplinar i competencial.
An Interview with Dr. Vincenza Tudini from the University of South Australia
Authors: Malerba Maria Luisa
Published: November 2018

Vincenza Tudini is a Senior Lecturer at the School of Communication, International Studies and Languages at the University of South Australia. She has a Ph.D. in Italian with a focus on critical analysis of contemporary narrative. Her more recent research and publications record is in the area of applied linguistics with a focus on Computer Mediated Communication. She has directed several projects in the area of Computer Assisted Language Learning (C.A.L.L.) including a project of the Australian Federation of Modern Language Teachers (AFMLTA) Language Resources on the Internet and a project of the Australian Language & Literacy Council Implications of Technology for Language Teaching. She is currently working on several projects that research and develop online language teaching and learning.
“Tarongeta” vol dir taronja petita por Bosch, Llop, Güell Bou, Fusté Suñé, Gimeno, Climent i Rovira, & Torra Sans (Godall Formacions)
Authors: Belotti Marcello
Published: November 2018

“Tarongeta” vol dir taronja petita, publicado por Godall Editorial en 2013, incluye seis textos finalistas del concurso “El català pel món”. Los autores son jóvenes profesores catalanes, todos nacidos entre la década de los setenta y la de los ochenta, algunos también son investigadores, escritores, poetas, que han vivido la experiencia de enseñar su lengua en los más diversos lugares del mundo.
Grammar instruction and writing skills at secondary school. An interview with Debra Myhill
Authors: Casadellà Marina
Published: November 2018

Debra Myhill est vice-doyen à la recherche et le transfert des connaissances, Faculté des sciences sociales et des études internationales à l'Université d'Exeter (Royaume-Uni), où il est le coordonnateur de stage de médias en anglais. Ses intérêts de recherche sont principalement dans le domaine du langage et de l'alphabétisation, en mettant l'accent sur l'enseignement de l'écriture; enseignement de la grammaire; genre et l'alphabétisation; et de parler.
Nota de les Editores
Authors: Dooly Melinda , Casadellà Marina
Published: November 2018

Amb aquest número del Bellaterra Journal of Teaching and Learning Language and Literature, presentem un monogràfic sobre ensenyament i aprenentatge de la composició escrita.
Social media, fandom and language learning: A roundtable with Shannon Sauro and Steven L. Thorne
Authors: Wang Dean
Published: November 2018

Last November, Dr. Shannon Sauro (Malmö University & Lund University) and Dr. Steven L. Thorne (Portland State University & University of Groningen) visited the UAB campus to give lectures on, respectively, ‘Fandom, Social Media and Learning’ and ‘Human development and semiotic remediation through mobile place-based gaming’. (...) Questions and responses are transcribed here.
Nota de la editora
Authors: Dooly Melinda
Published: November 2018

Empezamos el año académico en otoño con un tema muy interesante y provocativo. Nuestra autora invitada, Luci Nussbaum, reflexiona sobre la importancia de interrogar nuestra manera de entender las prácticas plurilingües del alumnado fuera del aula con el fin de abordar mejor la enseñanza de las lenguas dentro de ella.
COMPUTER AIDED ANALYSIS OF WEAR OF THE SURFACE LAYER WITH A PEARLITIC STRUCTURE USING AN AMSLER STAND
Authors: BĄKOWSKI Henryk
Published: November 2018

W pracy przedstawiono wyniki badań laboratoryjnych na stanowisku Amslera próbek wykonanych ze stali szynowej bez obróbki cieplnej o strukturze perlitycznej. Zaprezentowano warstwę wierzchnią zgładów metalograficznych po współpracy w różnych warunkach eksploatacji. Warstwa wierzchnia uległa zmianie na skutek zjawiska ratchettingu poprzez oddziaływanie różnych czynników eksploatacyjnych. Następnie posłużono się badaniami symulacyjnymi ze pomocą metody elementów skończonych (MES). Odzwierciedlono poszczególne strefy warstwy wierzchniej za pomocą systemu CAD. W oparciu o modele teoretyczne nadano poszczególnym strefom właściwości, aby określić warunki brzegowe niezbędne do przeprowadzenia obliczeń numerycznych. Uzyskane wyniki pozwoliły na określenie miejsc szczególnie narażonych na zużycie oraz rozkłady naprężeń i odkształceń umożliwiające wyznaczenie głębokości zalegania maksymalnych ww. wartości.
THE INFLUENCE OF SOLID LUBRICANTS USED
FOR THE LUBRICATION OF WHEEL FLANGES
ON RAILWAYS TO REDUCE THE CORROSION
OF RAILS
Authors: BĄKOWSKI Henryk
Published: November 2018

The paper presents the influence of selected solid lubricants used for the
lubrication of wheel flanges of railways on the formation and development of
corrosion. Tested solid lubricants consisted primarily of graphite, molybdenum
disulphide, and soybean oil additives. Moreover, grease sticks were selected to
make it possible to compare and evaluate their suitability in applying the lubrication of railway wheels. The study is based on the European standard that
allows the determination of wear in the test samples to determine the advantages
in relation to the processes of corrosion.
CFD ANALYSIS OF THE HYDRODYNAMIC LUBRICATION OF A MISALIGNED, SLIDE CONICAL BEARING
Authors: CZABAN Adam
Published: November 2018

The lateral loads carried by hydrodynamic bearings, and also their uneven distribution, introduce an additional axial misalignment between the shaft and sleeve. The machining and mounting errors also result in improper initial alignment of bearing shaft or sleeve. Furthermore, due to vibrations, misalignment of shaft fluctuates during the operation of the bearing. This has an impact on the operating parameters of the bearing, and, in extreme cases, where the maximum allowable value of the misalignment is exceeded, the bearing can be damaged. The aim of this work is to investigate the effect of misalignment on the hydrodynamic pressure distribution in the conical sliding bearing lubrication gap and on the bearing load carrying capacity and friction force values. This paper shows the result of a CFD simulation of hydrodynamic conical bearings lubrication with the assumption that the bearings are misaligned, i.e. where the rotation axis of bearing shaft is not parallel to the axis of the cone of the bearing sleeve. The commercial CFD software ANSYS Fluent was used in this research. It was assumed that the flow of lubricating oil is laminar, without slipping on bearing surfaces, and that the oil has non-Newtonian properties.
AN INVESTIGATION OF THE INFLUENCE OF CLIMATIC FACTORS ON THE EROSIVE WEAR KINETICS OF POLYMER COATINGS
Authors: KOTNAROWSKA Danuta , KOTNAROWSKI Andrzej
Published: November 2018

The paper presents investigation results concerning the influence of the modification with nanoparticles of silica (of mean grain size 12 nm or 20 nm) or aluminium trioxide (20 nm) of the structure of epoxy coatings on their resistance to climatic factors and the action of erosive particles. Epoxy coatings aged in natural climatic conditions showed an erosive resistance decrease with ageing. The erosive resistance decrease was accompanied by a hardness decrease as well as surface roughness increase. The highest resistance to erosive wear after 3 years of ageing revealed coatings modified with aluminium trioxide nanoparticles, while the lowest one showed coatings modified with silica nanoparticles of 12 nm mean grain size. Nanocoatings modified with aluminium trioxide nanoparticles also had the highest resistance to ageing; which was proven by the lowest increase of Ra and Rz surface profile parameter values with time, as well as by a high surface hardness, which was higher than hardness of new unmodified coatings.
ANALYSIS OF THE INFLUENCE OF FRICTION FORCE ON THE STRAINS OF GAS PIPELINE USING THE HILBERT-HUANG TRANSFORM
Authors: LEPIARCZYK Dariusz , GAWĘDZKI Wacław , TARNOWSKI Jerzy
Published: November 2018

The aim of the study was to determine the effect of friction forces on strains of a gas pipeline pipe in conditions of static and dynamic load. The experiments were conducted on a 28-metre section of pipe laid in quartz sand haunching. The source of dynamic loads was artificially generated soil vibration of a pulse character, which can be interpreted as seismic-like waves of mining origin. The static loads were applied by means of an actuator, which allowed the setting of different values of tension force acting along the pipe axis. The dynamic strain and vibration acceleration of the pipeline were measured during the experiments at different values of tension forces. The recorded signals were subjected to the time-domain decomposition by using the Hilbert-Huang transform. The method allows for the correct decomposition of the primary signal that describes the non-stationary and nonlinear phenomena as a sum of quasi-harmonic components whose amplitudes and frequencies are the parametric functions of time. The analysis included the determination of the influence of friction force in contact between the pipe and the sand haunching on the parameters of dynamic strain signals.
FRICTION PROCESSES OF SELECTED POLYMERS SLIDING ON STEEL AND DURALUMIN IN A LUBRICANT ENVIRONMENT
Authors: WIELEBA Wojciech , LEŚNIEWSKI Tadeusz , ELEMES Darhan , ELEMES Ainur
Published: November 2018

The article presents the results of tribological research into engineering polymers (POM, PEEK, PPS) cooperating in sliding motion with 316L steel and EN AW-2017A aluminium alloy in the presence of a liquid (water, hydraulic oil HLP68). This type of friction pair may occur in hydraulic systems (gear pumps, valves, etc.). For comparison, additionally, the results of tribological research carried out in dry friction conditions have been shown. In addition, the results of microscopic study of the sliding surfaces of polymeric materials have been presented. Analysis of the test results allows one to describe the processes of friction and wear of the studied sliding pairs.
THE EFFECT OF IRRADIATION WITH AN ELECTRON BEAM ON MECHANICAL, SCLEROMETRIC, AND TRIBOLOGICAL PROPERTIES OF PTFE WITH A GRAPHITE ADDITIVE
Authors: BARYLSKI Adrian , KAPTACZ Sławomir , ANIOŁEK Krzysztof , KUPKA Marian
Published: November 2018

Polytetrafluoroethylene (PTFE) with a 15% graphite additive was subjected to irradiation using an electron beam of energy of 10 MeV in doses of 26, 52, 78, 104, and 156 kGy. The effect of electron beam irradiation on the mechanical, sclerometric, and tribological properties of the material was examined. It was found that the modification through irradiation entailed a gradual increase in the microhardness and Young's modulus as the absorbed dose of irradiation increased. A stereometric analysis of the scratch traces on the material allowed for the determination of the coefficients of the wear micromechanism, β, and resistance to wear, Wβ. After irradiation (especially with a dose of 104 kGy), a significant quantity of the material showed traces of ploughing; the value of the wear resistance coefficient Wβ for the PTFE subjected to cross-linking also increased considerably, which indicated a significant reduction of the tribological wear in relation to the initial material. Examination of abrasive wear of PTFE was performed for the polymer in its initial state and after modification through radiation on a pin-on-disc test stand, T-01. The tests have shown more than a five times reduction of the linear wear during the interaction with a titanium counter-specimen.
MODELLING OF CHANGES IN SURFACE TOPOGRAPHY IN DRY SLIDING CONDITIONS
Authors: DZIERWA Andrzej , REIZER Rafał
Published: November 2018

Metrology of surface topography is presently so developed that, in some ways, we can predict the surface behaviour of the one part in co-operation with another element. We can single out two main approaches to the modelling of surface texture. In the first one, the modelling does not take into account the conditions of the technological or operational formation of the surface, while in the second, more complicated approach, modelling takes into account the real conditions of forming the surface. In this work, tribological tests were carried out in dry sliding conditions, and the analytical methodology of wear or worn surface. Approximations obtained using the second approach are usually worse than those using the first method [L. 8–10]. In the presented work, tribological tests in dry sliding conditions were carried out, and a numerical model to determine the cross-sectional area of wear in presented conditions was produced, and the results obtained using modelling and experimental tests were compared.
TRIBOLOGICAL PROPERTIES OF TI/A-C:H NANOCOMPOSITE CARBON BASED COATINGS
Authors: KOT Marcin , MAJOR Łukasz , LACKNER Jurgen , CHRONOWSKA-PRZYWARA Kinga
Published: November 2018

The paper presents the results of mechanical and tribological tests of Ti/a-C:H nanocomposite carbon coatings and a-C:H hydrogenated carbon coating. All coatings were deposited by magnetron sputtering technique at various acetylene gas flows in a vacuum chamber, resulting in different coatings properties. The conducted study determines hardness, elasticity modulus, fracture resistance, and tribological properties – wear and friction coefficient of deposited coatings. The lowest wear and coefficient of friction were exhibited coatings deposited at higher acetylene flows, 15-20 sccm. However, they are brittle and the critical load in scratch testing is several times smaller than in a case of softer coatings deposited at lower acetylene flow up to 10 sccm.
ASSESSING THE EFFECT OF BIODEGRADABLE CUTTING FLUID ON TOOL WEAR IN MACHINING
Authors: KOWALCZYK Joanna , NOWAKOWSKI Łukasz , MADEJ Monika , OZIMINA Dariusz
Published: November 2018

This paper is concerned with the wear of a tool in turning under dry and wet conditions. The fluid used in the tests was a biodegradable cutting fluid containing zinc aspartate. The tool surface was analysed using a Talysurf CCI Lite optical profiler and an SX80 stereo zoom microscope. The results indicate that the cutting fluid tested offers all the functions required in turning.
FORMING USAGE PROPERTIES OF LUBRICANTS BY THE FUNCTIONAL ADDITIVES
Authors: TRZOS Magdalena , SZCZEREK Marian
Published: November 2018

The article presents the results of analysis of improvement possibilities of lubricating properties by the modification of lubricants with the use of functional additives that improve resistance to the wear and scuffing of frictional couple. The research encompasses different base oils. Mineral oil and the synthetic oils, i.e. ester oil and hydrocarbon oil, were investigated. Tribological investigations were conducted with the use of a four ball apparatus. The research results were analysed with particular consideration of simultaneous effects of two types of additives, i.e. anti-wear and anti-scuffing. As the result of research, the possibilities of forming a lubricant’s anti-wear and anti-scuffing properties have been demonstrated through the selection of the percentage of additives. The limitation of simultaneous improvement of both resistance to wear and scuffing was also demonstrated. This limitation is due to the additives’ interactions.
SELF-LUBRICATING PROPERTIES OF THIN COATINGS BASED ON MOLYBDENUM DISULPHIDE
Authors: ZIMOWSKI Sławomir
Published: November 2018

The paper presents an analysis of the friction and wear processes of a composite coating based on molybdenum disulphide doped by tungsten and titanium, taking into account the impact of load and temperature in the contact zone. The tribological tests were performed at room temperature and at 300°C and 350°C in non-lubricated sliding contact with an Al2O3 ball. The characterization of the micromechanical properties and the adhesion of coatings to steel substrates were done by scratch testing. The analysis of the coatings wear and the sliding tribolayer formation was conducted by the observation of the friction track using light microscopy (LM) and scanning electron microscopy (SEM). The low hardness of the MoS2(Ti,W) coating, equal to 6 GPa, with the predominantly amorphous structure, allows for quick formation of the tribological contact and the sliding tribolayer creation. Due to self-lubricating properties, the coating has a high wear resistance and a low friction coefficient (below 0.1), both at room and elevated temperatures. The study allowed the determination of the operating temperature limit of the coating-substrate system in sliding point contact, which helped to specify the application area of such material.
THE TRIBOLOGICAL PROPERTIES OF LUBRICATING GREASES BASED ON RENEWABLE OILS
Authors: KOZDRACH Rafał
Published: November 2018

The paper discusses the influence of vegetable oil basis on lubricating properties of their selected compositions. Four vegetable oils were used for production of lubricating greases: rapeseed, sunflower, soybean, and castor, all thickened with modified silica of Aerosil® type. The tribological properties of lubricating greases based on vegetable oils were investigated. On their basis, the most beneficial compositions were selected. The tribological properties of greases were estimated via measurements of limiting load of wear (Goz/40), welding load (Pz), scuffing load (Pt), limiting load of scuffing (Poz), and the limiting pressure of seizure (Poz). Based on the obtained results, it may be concluded that the best antiwear properties were shown by the lubricating compositions based on rapeseed oil, whereas the best antiscuffing properties have compositions using castor oil as a disperse phase.
THE EFFECT OF AN ACCELERATED AGEING PROCESS ON TRIBOLOGICAL WEAR OF POLIMERIC ELEMENTS IN JOINT ENDOPROSTHESES
Authors: MRÓZ Adrian , WIELOWIEJSKA-GIERTUGA Agnieszka , WIŚNIEWSKI Tomasz , BARCZEWSKI Mateusz , ŁAPAJ Łukasz , GIERZYŃSKA-DOLNA Monika
Published: November 2018

The polymeric components of endoprostheses in in vivo conditions are subjected to the oxidation process (ageing). The paper presents the results of friction and wear testing performed with use of a knee-joint simulator. The polymeric parts were machined from UHMWPE and UHMWPE modified with the addition of vitamin E. The calorimetric analysis and tribological testing results confirm the negative effect of accelerated ageing in oxygen atmosphere on the tribological properties of UHMWPE as well as the antioxidative properties of vitamin E.
ASSESSMENT OF THE TRIBOLOGICAL PROPERTIES OF HARDFACING WELDING ALLOY Fe-Mn-C-B-Si-Ni-Cr IN DRY FRICTION CONDITIONS
Authors: PASHECHKO Mykhaylo , DZIEDZIC Krzysztof , DZIUBIŃSKA Anna , BARSZCZ Marcin
Published: November 2018

The paper assesses the tribological properties of hardfacing coatings produced by gas metal arc welding. Flux-cored wires were used as a welding material. The core mixture was based on the Fe-Mn-C-B-Si-Ni-Cr alloy. Seven types of flux-cored wires with different compositions were prepared. The flux-cored wires had a diameter of 2.4 mm. The tribological assessment was performed with an Amsler tribotester under dry friction conditions at different unit pressures: 3, 7, and 10 MPa. The results demonstrate that the coating L-6 has good tribological properties. The overlay weld had a hardness of 49 HRC. Following friction testing, the coatings were also examined with respect to their microhardness and microstructure.
THE INFLUENCE OF THE KIND OF COMPOSITE FRICTION MATERIAL ON MORPHOLOGY AND COMPOSITION OF ITS SURFACE LAYER AND TRIBOLOGICAL PROPERTIES
Authors: SZLICHTING Maciej , BIELIŃSKI Dariusz , GRAMS Jacek , PĘDZICH Zbigniew
Published: November 2018

Praca przedstawia charakterystykę materiałów stosowanych aktualnie w budowie okładzin hamulcowych samochodów osobowych, zwracając uwagę na ich wady i zalety. Na tym tle, kierując się oczekiwaniami ze strony klientów oraz biorąc pod uwagę najnowsze osiągnięcia w obszarze inżynierii kompozytów polimerowych i tribochemii. zaproponowano perspektywy postępu w obszarze materiałów ciernych. Rozważania zostały zilustrowane wynikami badań własnych dotyczących analizy morfologii i składu chemicznego powierzchni reprezentatywnych grup materiałów okładzin hamulcowych. Charakterystyki hamowania oraz mechanizm tarcia badanych kompozytów zostały zinterpretowane z punktu widzenia zmian zaobserwowanych w mikrostrukturze i składzie chemicznym ich powierzchni. Nawiązują one do wcześniejszych badań autorów związanych z tribochemiczną modyfikacją elementów węzła ciernego polimer-metal.
THE INFLUENCE OF THE TYPE OF GREASE
ON THE SYNERGY OF ITS COMPOSITION WITH
PTFE POWDER AND COPPER POWDER
Authors: KRAWIEC Stanisław , KRAWIEC Michał , LEŚNIEWSKI Tadeusz
Published: November 2018

Studies of the influence of the type of grease on the synergistic effect of its
compositions with PTFE powder and of copper during the lubrication of steel
sliding pairs working in mixed friction area of were presented. Two greases, car
grease 1S with a lithium thickener and grease STP with calcium thickener, were
adopted for analysis. As fillers in the two lubricants, powders of two solid
lubricants were PTFE and copper were used. Three lubricating compositions
were tested for each of the adopted greases. Two compositions contained one
filler of 5% by weight, and the third composition contained the two fillers in the
same proportion (5% each). The lubricating properties of the adopted compositions were evaluated based on an experiment conducted with the use of
a four–ball extreme pressure tester according to the standard PN-76/ C04147.
The effectiveness of the analysed lubricants was evaluated according to four
criterion values (wear of the balls d, fusion point Fz, limit wear load Goz, and
wear index Ih). The results were statistically handled at the confidence level of
95% using Student’s t-test. The developed test results are shown graphically.
Appropriate conclusions were drawn.
AN EXAMINATION OF THE CONDITION OF WORKING SURFACES OF CRANKSHAFT CRANKPINS AND JOURNALS BASED ON THE MATERIAL FRACTION CURVES
Authors: STAWICKI Tomasz , SĘDŁAK Paweł
Published: November 2018

The paper focuses on the significance of the microgeometry of the working surfaces of crankpins and the main bearing journals on the durability and reliability of farm tractor engines. Alternative surface roughness parameters for the quantitative description of the material fraction curve are suggested to be applied as factors facilitating the evaluation of the performance properties of the working surfaces of the crankpins and main bearing journals. The results of graphometric profile examination of new crankshafts, the crankshafts recognized as run-in, and reworked ones have been provided and the assessment of the results concerned was basis for the evaluation of the proposed methodology for the examination of the microgeometry of the surfaces concerned. The results confirmed the suitability of slope indicators of straight lines describing the behaviour of material fraction as the evaluation parameters of performance properties of the working surfaces of the crankpins and main bearing journals.
SURFACE RANDOM PARAMETERS FOR ENDOPROSTHESIS LUBRICATION
Authors: WIERZCHOLSKI Krzysztof
Published: November 2018

Within the last ten years in the European Union the number of bone fractures caused by the osteoarthritis increased twofold. More than 100000 hip or knee joints in total have been implanted in Germany during one year. Within ten years, 5% of them have failed by aseptic loosening. The non-invasive determination of friction forces and the control of their values during lubrication of cartilage cells on the superficial layer of human joint surfaces before implantation have a significant but not sufficient influence on the observation of the early abrasive wear of cartilage joint and the development of osteoporosis. From this fact was drawn the inspiration for the performed investigations referring the endoprosthesis surface parameters, because knowledge of the roughness of prosthesis surfaces and friction forces and their control methods makes it possible to provide the necessary random standard deviation of gap height and finally information about implantation possibility. This paper has been prepared based on the objective knowledge gained from the author’s experimental and theoretical experiences to represent the methodology and goal of the idea described in the study and to make possible a wider discussion on this subject for further developments during the realization of various bioengineering projects in the field of hydrodynamic artificial human and humanoid robots joints.
THE SELECTION OF PRELOAD IN ANGULAR CONTACT BALL BEARINGS ACCORDING TO THE DURABILITY CRITERION
Authors: KACZOR Jarosław , RACZYŃSKI Andrzej
Published: November 2018

The regulation of the preload of angular contact ball bearings is mentioned in specialist literature, but only as a practical activity carried out based on experience, still without selection methodology. At present, there exists no widely accessible method of this load selection. Neither the literature on the subject nor catalogues of bearings producers give recommendations for the selection of this parameter, which is most often perceived intuitively. Still, it is known that its wrong selection can have a catastrophic influence on the durability of bearings. In consequence, there exists a problem of the accurate choice of preload (i.e. of such a preload that the durability of bearings will not be significantly decreased). The aim of the study is to determine the maximum preload in angular contact ball bearings by the criterion of durability, taking into account shaft flexibility and the flexibility of bearings. In order to determine a general influence of preload on fatigue life of bearings, numerous calculations were made for different locations of the plane of load.
MEASUREMENT OF THE STATIC FRICTION COEFFICIENT BETWEEN A poly-V belt 5pk AND A PULLEY UNDER DRY CONDITIONS
Authors: KUBAS Krzysztof
Published: November 2018

The paper presents the results of experimental measurements of static friction forces between a poly-V belt 5pk and a pulley on a specialised research stand. An average effective static coefficient is assumed depending on the wrap angle and preload force. Different shapes and positions of curves of the measured values for lower wrap angles are found, with similar curves in the set of measurements with higher angles. The Nelder-Mead optimisation method is proposed to approximate the measured results by a nonlinear function and to achieve good accordance. The dependence of the effective friction coefficient on the rest time between measurements is also presented.
TRIBOLOGICAL PROPERTIES AND TRIBOCHEMICAL CONVERSION OF BIONIC LUBRICANTS BASED ON SODIUM HYALURONATE
Authors: MOLENDA Jarosław
Published: November 2018

The aim of the study was to investigate the influence of the sodium hyaluronate in water on the tribological properties of the composition as well as an instrumental analysis of changes in the molecular structure of the bionic lubricant during friction. Tribological tests were carried out using a MCR 102 rheometer in a ball-plate combination made of bearing steel. Based on the recorded friction coefficient values, it was found that a significant improvement in friction conditions may be achieved using a composition containing 0.5% (m / m) of sodium hyaluronate in water. In this case, the value of the friction coefficient can be even below 0.1. This effect was also reflected in the minimization of material loses by about 24% compared to the wear of a friction pair lubricated only with water. During friction, the active component of the lubricant is subjected to tribo-chemical conversion and the resulting products are deposited on the working surfaces of the friction pair. The chemical structure of the resulting products was examined using SEM/EDS, XPS and FTIR. It was found that the active chemical moieties undergoing chemical conversion are the oxygen and nitrogen functional groups present in sodium hyaluronate.