bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a single session of whole-body vibration exercise on haematological and biochemical parameters, and serum cortisol levels in cats
Authors: Blazizza M.F.S. , Rahal S.C. , Santos I.F.C. , Silva B.M. , Ferreira G.M. , Oba E. , Tsunemi M.H. , Takahira R.K.
Published: October 2020

The aim of this study was to evaluate the effects of a single-session of whole-body vibration (WBV) exercise on haematological and serum biochemical parameters and serum cortisol levels in healthy adult cats. Ten healthy neutered crossbred cats, five males and five females, aged 2 to 4 years and weighing 3.25-5.15 kg, were enrolled. All cats were tested in the same period starting at 12:00 a.m. and under same environmental conditions. A 1 h period of acclimatisation and rest was completed prior to the WBV session. During the WBV session, the cat was placed in a standing position on the centre of the vibrating platform. Each cat was exposed to a single WBV session. The protocol was 30 Hz for 5 min, followed by 50 Hz for 5 min and finishing with 30 Hz for 5 min. The peak displacements were 3.10 mm and 3.98 mm and the peak accelerations 55.0 m/s and 195.96 m/s. Complete blood cell count, serum biochemistry (alanine aminotransferase, creatinine, creatine phosphokinase) and serum cortisol were determined at three time-points: before (T0), immediately after (T1), and at 4 h after the end of the WBV session (T2). Immediately after increasing the frequency from 30 to 50 Hz, two cats (20%) tried to sit and showed signs of agitation that ceased after 15 s. No cat tried to jump out. The variables presented no statistically significant differences among the time-points. In conclusion, a 15 min session of WBV exercise at frequencies of 30, 50 and 30 Hz does not cause significant changes in haematological or serum biochemical parameters, nor in serum cortisol levels in healthy adult cats.
Doctoral Students' Responses to Writing Critique: Messages for Teachers
Authors: Eyres Sandra J , Hatch Deborah H , Turner Susan B , West Maureen
Published: October 2020

ABSTRACT

Writing is a major part of learning scholarship in a discipline. Therefore, it is important to understand what promotes and what hinders this learning. In transcribed interviews, 15 doctoral students in nursing at a large university described to us what they saw as helpful or not helpful about responses to their writing. The themes take the form of messages for teachers that, when reported in the context of the composition literature, provide helpful suggestions for teachers.
On the first general Zagreb eccentricity index
Authors: Jamil Muhammad Kamran , Imran Muhammad , Javed Aisha , Hasni Roslan
Published: October 2020

In a graph G, the distance between two vertices is the length of the shortest path between them. The maximum distance between a vertex to any other vertex is considered as the eccentricity of the vertex. In this paper, we introduce the first general Zagreb eccentricity index and found upper and lower bounds on this index in terms of order, size and diameter. Moreover, we characterize the extremal graphs in the class of trees, trees with pendant vertices and bipartite graphs. Results on some famous topological indices can be presented as the corollaries of our main results.
Attractors for a quasilinear viscoelastic equation with nonlinear damping and memory
Authors: Peng Xiaoming , Shang Yadong
Published: October 2020

In this paper, the long time behavior of a quasilinear viscoelastic equation with nonlinear damping is considered. Under suitable assumptions, the existence of global attractors is established.
Del manuscrito al primitivo impreso: la labor editora de Francesc Argi­lagues (fl. ca. 1470-1508) en el Renacimiento médico italiano
Authors: Arrizabalaga Jon , García-Ballester Luis , Gil-Aristu José Luis
Published: October 2020

El proceso de transición del manuscrito médico al primitivo impreso en la Europa de las últimas décadas del siglo XV y primeras del XVI no ha sido suficientemente estudiado. En este trabajo se presenta a un protagonista destacado (aunque prácticamente desconocido hasta la fecha) de este proceso desde su papel de editor. Se trata de Francesc Argilagues {fl. c. 1470-1508), médico valenciano que, tras cursar sus estudios en Itaüa, se estableció profesionalmente allí, donde fue uno de los más tempranos editores de obras médicas para la imprenta, entre ellas dos de primer orden en la medicina universitaria bajomedieval y renacentista: el conjunto de escritos conocido por el nombre de Articella (en 1483 y 1487) y el Conciliator differentiarum philosophorum et praecipue medicorum de Pietro d'Abano (en 1483, 1490 y 1496). Hemos abordado la personalidad y obra de Francesc Argilagues a partir de diferentes fuentes básicas de información. Dado el indudable interés de los prólogos y de la nota introductoria que dirigió a los lectores de las dos obras por él editadas, se ofrece también su edición y traducción castellana.
Obras españolas sobre historia natural y materia médica americanas en la Italia del siglo XVI
Authors: Pardo Tomás José
Published: October 2020

La producción científica hispana sobre la historia natural y la materia médica de las tierras americanas tuvo una acogida muy especial en el mundo italiano a lo largo del siglo XVI. A través del estudio de las ediciones de estas obras, el trabajo trata de establecer los perfiles generales de la difusión de las obras en Italia, la localización, la periodicidad y el ritmo de la misma y los grupos de científicos, editores y traductores que impulsaron este proceso. Puede afirmarse que la presencia de esta producción científica española fue importante, se mantuvo constante a lo largo de la centuria y experimentó una progresiva especialización, pasando desde primeras noticias sobre el Nuevo Mundo al comienzo de asimilación de la nueva materia médica, fundamentalmente a través de la obra de Monardes. Por otra parte, el ambiente científico y libresco veneciano se perfiló como el centro difusor más importante de esta aportación científica española.
La primera versión castellana de De Revolutionibus Orbium Caelestium: Juan Cedillo Díaz (1620-1625)
Authors: Esteban Piñeiro Mariano , Gómez Crespo Félix
Published: October 2020

En la presente publicación se da a conocer la existencia de un manuscrito inédito que se encuentra en la Biblioteca Nacional de Madrid, bajo la signatura Ms-9091. En dicho volumen se halla la obra Ydea Astronómica de la Fábrica del Mundo y movimiento de los cuerpos celestiales, de Juan Cedillo Díaz, Cosmógrafo Mayor del Consejo de Indias y Catedrático de Matemáticas de la cátedra de la Corte desde 1611 hasta 1625. El estudio de esta obra revela que se trata de una traducción casi literal del texto de Nicolás Copérnico De Revolutionibus Orbium Caelestium, (1543), Nuremberg. Es, por tanto, la primera traducción castellana de la que se tiene noticia (aun teniendo en cuenta que se halla incompleta, pues le faltan los dos últimos libros de los cinco de que consta el título original) e incluso la primera en Europa, de acuerdo con los datos que han podido recoger los autores.
Los dos libros de la geometría Práctica de Fineo traducidos por Girava y ordenados por Lastanosa
Authors: García Tapia Nicolás , Vicente Maroto M.ª Isabel
Published: October 2020

La traducción de Los dos libros de la Geometría Práctica (1553) de Fineo que se encuentra manuscrita en la Biblioteca Nacional de Madrid, se ha atribuido tradicionalmente a Pedro Juan de Lastanosa y su ordenación a Jerónimo Girava. En contra de lo que se ha dicho por algunos autores, Lastanosa no era matemático, ni menos aún cosmógrafo, sino maquinario y maestro mayor de fortificaciones al servicio de Felipe U. Fue en realidad Girava quien hizo la traducción de la Geometría Práctica, en virtud de su cargo de cosmógrafo e ingeniero al servicio de Carlos I. Lastanosa se limitó a recoger el manuscrito y ordenarlo para su posible publicación que no tuvo lugar. La confusión proviene del añadido de una portada que se hizo al manuscrito un siglo después. Aclaramos en este artículo estos puntos y analizamos el contenido de esta Geomería Práctica y su influencia en otros matemáticos españoles.
La epidemia de tercianas de 1786 en la antigua provincia de Toledo
Authors: García Ruipérez Mariano , Sánchez González Ramón
Published: October 2020

Tras un repaso a las pocas aportaciones que sobre historia de la medicina se han publicado relativas a la provincia de Toledo y a la literatura médica sobre tercianas en la segunda mitad del siglo XVIII, el artículo se centra en describir la situación general existente entre 1785-1787 con la ayuda de la Relación histórica… de P. Escolano; después prosigue con el examen de las causas de las tercianas padecidas en la provincia de Toledo y el desarrollo de la epidemia en esos años, deteniéndonos particularmente en la villa de Escalona. Se compara su incidencia por partidos para terminar con los métodos curativos y las consecuencias del azote epidémico. Además se incluye un apéndice en el que se relacionan todas las poblaciones de la provincia de Toledo, con su número de habitantes, enfermos tercianarios, fallecidos tercianarios y la morbilidad y mortalidad palúdica.
La enseñanza de la medicina clínica en la Valencia del siglo XIX: la labor de Juan Bautista Peset y Vidal
Authors: Peset Mancebo Mariano
Published: October 2020

El autor hace un análisis de historias clínicas realizadas por estudiantes bajo la dirección de Juan Bautista Peset y Vidal (1821-1885).'Se percibe el inicio de la «medicina de laboratorio» y superación de la mentalidad anatomoclínica. En una primera parte se estudian las estadísticas que aparecen en las historias clínicas; y en el segundo apartado sus contenidos para situarlas en una época y en unos saberes médicos, ya que el director es considerado como una figura importante en estas corrientes.
Sobre los orígenes de la Psiquiatría cubana: la obra de Gustavo López (1860-1912)
Authors: Huertas Rafael
Published: October 2020

El presente trabajo pretende una primera aproximación al nacimiento de la medicina mental en la Isla de Cuba a través de las aportaciones teóricas de Gustavo López (1860-1912), considerado como uno de los primeros introductores del alienismo en ese país del Caribe. Se valora de manera particular, la influencia del degeneracionismo francés y de la antropología criminal italiana en la praxis clínica y forense de la psiquiatría cubana finisecular, así como las principales peculiaridades de su elaboración doctrinal.
La Real Sociedad Patriótica de La Habana en el rescate de la variedad «naturalizada» del trigo de Villa Clara
Authors: Misas Jiménez Rolando
Published: October 2020

El presente artículo forma parte de un trabajo más amplio sobre el cultivo del trigo, dentro de la tendencia hacia la diversificación y la tecnificación agrícolas en la Real Sociedad Patriótica de La Habana, institución creada en 1793 que desempeñó un papel decisivo en la promoción de estas nuevas ideas. Para el estudio nos basamos preferentemente en las Memorias de dicha Sociedad y en particular en la memoria de Antonio Bachiller y Morales, presidente de la Sección de Agricultura, publicada en 1848.
Felipe Poey y los estudios sobre la ciguatera
Authors: González López Rosa M.
Published: October 2020

Se analiza la figura de José Felipe Poey cómo uno de los grandes naturalistas cubanos que desarrolló sus actividades en muchos campos del saber durante el siglo XIX. El artículo se centra en sus trabajos dentro de la Ictiología cubana y consta de dos partes. En la primera se refiere el autor al estudio que realizó Poey sobre la ciguatera, enfermedad ocasionada por la ingestión humana de pescado tóxico. Describe los peces que producen la enfermedad, el número de especies, los síntomas, las precauciones y los métodos curativos. Aporta datos concretos sobre las especies tóxicas, basándose en los conocimientos anteriores de otros naturalistas que como Antonio Parra se habían preocupado del tema. También se pone de manifiesto el interés que Poey tenía por la Filología al analizar el origen del término «ciguatera». En la segunda parte se preocupa por las normas que regulaban la actividad pesquera que regía en Cuba en su tiempo y muestra sus opiniones en materia legal respecto a esta «Policía de la pesca» velando por la salud de los consumidores sin atentar contra la industria, que este sector económico suponía para la Isla.
Una aproximación a la expedición «sécreta» de Ventura Barcaíztegui, 1790-1793, y los reconocimientos de la parte oriental de Cuba
Authors: González-Ripoll Dolores
Published: October 2020

En el panorama de las expediciones científicas que España emprendió en el siglo XVIII figuran las destinadas a levantar planos y mapas, cuya mayor pujanza fue a partir de 1783, fecha de la puesta en marcha de un verdadero programa de reconocimientos hidrográficos de las zonas neurálgicas del imperio. La isla de Cuba, el más importante bastión español en el Caribe, recibió en 1790 la expedición comandada por el marino Ventura Barcaíztegui para levantar los mapas de la zona oriental, menos conocida y menos poblada, y examinar la riqueza forestal del área para surtir el astillero habanero. En el artículo se esboza la conformación de la expedición y sus primeros resultados.
La expedición de Sessé en Cuba y Puerto Rico
Authors: Puig-Samper Miguel Angel , Maldonado J. Luis
Published: October 2020

Con este trabajo queremos dar a conocer, quizás, uno de los aspectos menos estudiados de la Expedición Botánica a Nueva España. Se trata de la Comisión que realizó el viaje de exploración y estudio de la Historia Natural de las Islas de Barlovento desde 1795 a 1798; estaba formada por una parte del grupo expedicionario de Nueva España al mando de su director, Martín de Sessé, e integrada además por el farmacéutico Jaime Senseve y el pintor Atanasio Echevarría. Se hace hincapié en la relación que los expedicionarios mantuvieron con los miembros de las instituciones reformistas más prestigiosas de Cuba: la Sociedad Patriótica y el Real Consulado de La Habana, así como con los contactos y colaboración mantenidos con la otra expedición española, al mando del Conde de Mopox, que en esa fecha coincidieron en la Isla. También se recalcan las iniciativas y el papel determinante que tuvo esta Comisión en la creación del futuro Jardín Botánico de La Habana y de la consolidación de la Botánica moderna en la Isla.
El estudio de la travesía de Cartagena de Indias por la Expedición Hidrográfica del Atlas de la América Septentrional
Authors: Lucena Giraldo Manuel
Published: October 2020

Desde el inicio de las reformas borbónicas la carencia de una cartografía científica del Caribe constituyó uno de los mayores problemas de la estrategia española en el área. Si la ausencia de cartas y planos aumentaba los peligros de la navegación y limitaba el comercio en tiempo de paz, en época de guerra limitaba la eficacia de los movimientos navales y exponía a las escuadras a peligros innecesarios. Durante la culminación de las reformas borbónicas en América (1787-1792) la corona española afrontó decididamente el problema, organizando la expedición hidrográfica del Atlas americano. Entre 1792 y 1795 su primera división cartografió las islas de barlovento y sotavento y las grandes Antillas, mientras la segunda realizaba idéntica labor en Tierra Firme. Asentada en Cartagena de Indias desde 1794, su orden de regreso se pospuso por la necesidad de estudiar la ruta a La Habana, constituida en punto clave para el abastecimiento militar y el desarrollo comercial del Caribe español. En tres campañas hidrográficas consecutivas (1803-1805) los miembros de la segunda división de bergantines fijaron posiciones astronómicas y prepararon cartas de los obstáculos para la navegación, por lo que en adelante los peligros de tan importante ruta se pudieron evitar.
Étude des catégories opératives pour analyser l’activité d’enseignants
Authors: Veyrac Hélène , Blanc Julie
Published: October 2020

La catégorisation en tant que processus de base de la pensée, est considérée comme un moyen de rendre compte d’une part de l’activité. Elle est rendue accessible à l’analyse par un protocole de recueil nommé « étude des catégories opératives ». Ce protocole s’inscrit dans la lignée de recherches sur les catégorisations des élèves par les enseignants et le complète par une phase d’expression des règles d’action, s’appuyant sur le concept de schème. À l’aide du trombinoscope des élèves de leur classe, 67 professeurs de 6 lycées rendent compte de leur perception des élèves, par des regroupements de photographies. Ces regroupements constituent des catégories opératives, pour lesquelles les enseignants énoncent leurs pratiques pédagogiques spécifiques. Le protocole de recueil et de traitement des données, illustré par un exemple relatif à la régulation de la participation des élèves en classe, permet de donner des indications précises sur la méthode. Les résultats montrent que des enseignants qui désignent de manière semblable des catégories d’élèves, n’évoquent pas systématiquement des règles d’action identiques. Ils montrent par ailleurs qu’un enseignant mobilise de multiples caractéristiques pour décrire les élèves de sa classe. Enfin, ils rendent compte d’une spécialisation du regard des enseignants sur leurs élèves : un ensemble d’élèves est perçu sous certaines caractéristiques qui ne seront pas pertinentes pour d’autres ensembles d’élèves. Cette approche complète celles visant à décrire les traitements différenciés des élèves par les enseignants. Appliquée pour investiguer d’autres catégories opératives, elle peut enrichir les analyses de l’activité, particulièrement pour rendre compte de variabilités intra-individuelles.
Analyse des liens de la typicité catégorielle des élèves avec la quantité et qualité des interactions en classe
Authors: Laflotte Lara
Published: October 2020

Ce texte a pour objectifs de vérifier l’existence de catégories d’élèves dans le bagage cognitif des enseignants ainsi que l’effet du degré d’appartenance catégorielle des élèves sur les interactions en classe. Pour ce faire, deux études sont réalisées dans le canton de Genève auprès d’enseignants du primaire et de leur classe. L’étude 1 invite vingt-trois enseignants à effectuer trois tâches de catégorisation d’élèves. Durant l’étude 2, huit enseignants sont observés et filmés in situ afin d’encoder leurs interactions avec les élèves et de les rapporter à leurs catégorisations. Les résultats de l’étude 1 vérifient l’existence de trois à cinq catégories d’élèves suivant l’approche engagée, et la présence d’élèves prototypiques au sein de ces catégories. Pour l’étude 2, l’analyse factorielle appliquée sur les données des interactions permet de constater cinq types d’épisodes interactifs en classe. Par des analyses de régression, nous observons que la typicité des élèves à leur catégorie a un impact faible sur les conduites pédagogiques menées par l’enseignant. Ces constats nous questionnent sur la formation des enseignants et permettent d’engager différentes perspectives de recherche.
Les nouveaux internats d’éducation prioritaire. Apports et limites de dispositifs pédagogiques contemporains d'accompagnement scolaire
Authors: Lescouarch Laurent , Pirone Filippo
Published: October 2020

Cet article développe une analyse du modèle pédagogique d’accompagnement scolaire dans les nouveaux internats développés dans le cadre des politiques d’éducation prioritaire. Dans les textes institutionnels, ils sont supposés octroyer un cadre idéal pour des élèves scolairement et culturellement « empêchés » par leur milieu d’origine en permettant une « ré-internalisation » d’activités d’apprentissage qui ont été depuis longtemps dévolues « aux marges » du système scolaire. Nos propos s’appuient sur une étude pédagogique et sociologique des conditions des activités de soutien scolaire et de socialisation au « métier d’élève », ainsi que des manières dont les acteurs les structurent au quotidien. Les résultats de cette étude montrent que ces dispositifs sont caractérisés par les mêmes limites que les dispositifs contemporains d’accompagnement scolaire : peu efficaces en tant qu’espace-temps assurant une continuité entre transmission et apprentissage des savoirs, ils restent majoritairement profitables aux élèves possédant au préalable des dispositions sociocognitives telles que l’autonomie pédagogique et une certaine familiarité avec la forme scolaire.
EU FinTech Index
Authors: Boitan Iustina Alina , Barbu Teodora Cristina
Published: October 2020

The chapter focuses on the innovative financial technology called FinTech and explores its prospects for becoming a catalyst for financial inclusion. The novelty of the research approach resides in being the first study computing an EU FinTech index for the EU member countries. The index gathers four dimensions and provides insights on whether the FinTech environment in one country is better or worse compared to other countries in the sample. Countries' ranking based on index scores computed for two different years show that Sweden, Finland, Luxembourg, and Germany are always placed on the top of the hierarchy. Therefore, they exhibit real development opportunities in this regard. At the opposite are some countries in South-Eastern Europe that persistently record the lowest FinTech index scores; thus, there is still room for improvements in terms of market players' presence, existing regulation, access to digital financial inclusion.
Blockchain-Based Tokens as Financing Instruments
Authors: Ante Lennart
Published: October 2020

Blockchain technology represents a technological basis with which existing corporate financing processes can be supplemented. The issuance of digital tokens offers several potential advantages such as tradability, efficiency, automation, and cost benefits compared to traditional financial products. This transformation of financing processes and capital markets can allow small and medium-sized enterprises (SMEs) to access capital markets and at the same time close existing retail investment gaps. In this chapter, the challenges of SME financing are described and blockchain-based financing (initial coin offerings [ICOs] and security token offerings [STOs]) is introduced. The blockchain-based financing mechanisms are compared with conventional forms of financing and potentials and challenges are discussed. In conclusion, it is stated that potential clearly outweighs risk and that the majority of all existing challenges can be tackled through sensible and coordinated regulation.
The Digital Economy in the Context of Foreign Direct Investment Flows
Authors: Hintošová Aneta Bobenič
Published: October 2020

The main objective of the chapter is to provide a comprehensive overview of the development of the digital economy in the context of foreign direct investment flows, especially from the European Union member states point of view. First, the term and conceptualization of the digital economy is introduced, followed by an overview of theoretical background and empirical findings related to the role of foreign direct investment in the digital transformation of the economy. In this regard, the nature, position, and international footprint of digital multinational enterprises are also analyzed. The level of the digital economy and society development in the context of foreign direct investment flows is evaluated specifically in the conditions of the European Union member states. The conclusion summarizes the main partial findings, evaluates them in a mutual context, and brings implications for future research.
Social Entrepreneurship, Smart Brands, and Epic Social Learning Networks
Authors: Kalogeras Stavroula
Published: October 2020

This study explores how brand cultures can become learning communities and highlights how social networking sites can emerge as social learning platforms by way of content, conversations, and community. The purpose of this chapter is to examine the concept of learning content in online social learning networks that are initiated by a commercial enterprise to provide a competitive advantage while at the same time providing social good. The proposed framework builds a bridge between the organization and the consumer, takes into account Generation Z, and looks at self-development and knowledge consumption as the key benefit. The work considers transmedia storytelling which has emerged in marketing to expand the brand story. The concept of transmedia learning networks and brand-consumer value-competitiveness model is proposed to show the value proposition of knowledge consumption. The work embraces learning communities, introduces the theory of conversationisim, and encourages participation and conversation on a global scale.
Laser Implantation of Niobium and Titanium-Based Particles on Hot Working Tool Surfaces for Improving the Tribological Performance within Hot Stamping
Authors: Schirdewahn Stephan , Spranger Felix , Hilgenberg Kai , Merklein Marion
Published: October 2020

Within the scope of this work, a new approach named laser implantation process has been investigated, in order to improve the tribological performance of hot stamping tools. This surface engineering technology enables the generation of dome-shaped, elevated and highly wear resistant microfeatures on tool surfaces in consequence of a localized dispersing of hard ceramic particles via pulsed laser radiation. As a result, the topography and material properties of the tool and thus the tribological interactions at the blank-die interface are locally influenced. However, a suitable selection of hard ceramic particles is imperative for generating defect-free surface features with a high share of homogenously disturbed particles. For this purpose, different niobium (NbB2 and NbC) as well as titanium-based (TiB2 and TiC) materials were embedded on hot working tool specimens and subsequently analyzed with regard to their resulting shape and mechanical properties. Afterwards, modified pin-on-disk tests were carried out by using conventional and laser-implanted tool surfaces, in order to evaluate the wear and friction behavior of both tooling systems.
Temperature Measurement on Tool Surfaces by Wear Resistant PVD Sensor Coatings
Authors: Bobzin Kirsten , Brögelmann Tobias , Kruppe Nathan Christopher , Janowitz Julia
Published: October 2020

In manufacturing technology, sensors are important elements for monitoring process parameters and for recording data in the Industrie 4.0. Thin sensors manufactured by means of physical vapor deposition (PVD) offer a way to combine wear and corrosion protection on the one hand and the integration of a temperature sensor function on the other hand. For the analysis of the performance of PVD sensor coatings based on the thermoelectric effect, no standardized methods and procedures are state of the art. In this paper a measuring setup is presented, which allows reference measurements using a calibrated thermocouple and a thermographic camera besides the potential difference measurement of the sensor coating. Two measuring modes, which allow a continuous and a discontinuous measurement, are presented. The measuring methodology was evaluated using the PVD sensor coating Al2O3+Ni+NiCr+Al2O3. This multilayer sensor coating was deposited using an industrial coating unit and was tested with regard to the sensor properties. The deposition technology used for the sensor coating results in an interface without defects between the two sensor layers with a smooth transition. This provides a suitable electrical contact and a promising compound adhesion. The results show a suitable and detailed measurement of temperature and potential differences by means of calibrated measurement methods and the sensor coating. The measured results are reproducible and show a linear relationship between the potential difference and the surface temperature.
Determination of Strain Rate Depended Stress and Strain Fields in PVD Coatings on Cemented Carbide Inserts during the Repetitive Impact Test
Authors: Bouzakis Antonios , Skordaris G. , Bouzakis Konstantinos Dionysios , Gökcen Mehmet Gökhan , Boumpakis Apostolos , Batuk Ahmet-Ugur , Sisman Süleyman , Serbes Sefer Arda
Published: October 2020

Recently, stress, strain, strain-rate dependent curves for cemented carbide have become an established tool for evaluating the mechanical properties. In this paper, related strain-rate dependent data of a K05 insert were employed to define the developed stress and strain fields occurring in the compound coating-substrate at impact forces of various durations. In this way, the occurring maximum strains at various impact loads and times were analytically calculated. These maximum values and related fatigue endurance coating strain-rate dependent limits were consequently used to validate published coating fatigue critical impact forces associated with certain impact times.
Correlation between Coating Properties and Thermal Load of Craln-Coated Cutting Tools during Machining of AISI4140
Authors: Breidenstein Bernd , Denkena Berend , Heckemeyer Arnd , Beblein Sascha
Published: October 2020

In this study a novel inverse hybrid experimental-simulative approach to the determination of the thermal tool load as a function of the coating properties during orthogonal turning of AISI4140 with Cr1-xAlxN-coated cemented carbide tools is presented. The approach consists of an experimental determination of the internal tool temperatures by means of fiber-optic pyrometry as input for an inverse FEM-based simulation algorithm to calculate the surface temperatures. Based on a parameter study, the coating thickness s and the thermal conductivity of the coating λc were identified as the main factors influencing the thermal tool load. The combined influence of these properties was described via the thermal resistance R. It could be shown that the average thermal load on the tool surface increases with increasing thermal resistance R.
Residual Stress Measurements in PVD Coatings of Carbide Cutting Tools Directly in the Cutting Edge
Authors: Breidenstein Bernd , Vogel Nils , Dietrich Marcel , Behrens Harald , Andersson Jon M.
Published: October 2020

Residual stress measurements directly in the coated cutting edge are not possible with X-ray diffraction (XRD) due to the diameter of the X-ray beam. On the other hand, Raman microscopy enables measurements on the micrometer scale. Parameter variations in the PVD process were used to provide different residual stress states in (Al,Ti)N coatings on carbide cutting tools. They were examined by XRD in regions that can be reliably measured. The same area was then examined by Raman microscopy to determine the relationship of Raman peaks to the residual stress. Local high-resolution Raman measurements were then taken at the cutting edge and further influences on the Raman peak position besides residual stresses were excluded. In order to analyze the relationship between Raman peak shift and residual stress state, measurements were performed during a bending load. Finally, an outlook on further investigations is given.
Surface Modification of Aluminium Alloy by a Silver Nanoparticle-Doped Coating and Examination of Anticorrosion Protection
Authors: Prospathopoulos Alexandros , Pavlidou Eleni , Michailidis Nikolaos
Published: October 2020

Aluminium alloys are among the metals that can be easily passivated, demonstrating notable anticorrosion properties. Under aggressive environments, like in seawater, corrosion may appear though due to presence of chloride ions (pH>8.5) leading to pitting failures. The objectives of the presented research were to examine the possibility of functionalizing the surface of an aluminium alloy through a polydopamine (PDA) layer with homogeneously dispersed silver nanoparticles (AgNPs) and examine the corrosion behaviour of the nanostructured coating. The development of a PDA coating provides a promising approach for immobilization of silver nanoparticles onto AA6061 substrate. Exposure to salt spray for 60 h and assessment of the corrosion status through various methods were applied. Depending on the process parameters for the fabrication of the PDA-AgNPs layer, an enhanced corrosion protection was achieved compared to the undoped with AgNPs film and the uncoated Aluminium alloy.
Applicability of Solid Lubricant Coatings in Cold Rod Extrusion of Stainless Steels
Authors: Jobst Andreas , Merklein Marion
Published: October 2020

Cold extrusion is an established technology for the production of dimensionally accurate components in large series. Due to the high material and energy efficiency, a resource-saving manufacturing of high-performance parts is possible. Forming at room temperature leads to an advantageous grain structure and work hardening of the material, resulting in components with favorable operating characteristics. Nevertheless, a challenge is the generation of residual stresses during forming, which are influencing the fatigue behavior. The modification of the tribological conditions is one method for influencing the parts’ residual stress state. However, the high strength and work hardening of the materials formed at room temperature leads to high tribological loads between billet and die. These challenges are intensified by the increasing use of stainless steels due to growing demands for corrosion resistant components. The aim followed within this paper is therefore to investigate the applicability of typical lubricant coatings in the forward rod extrusion of stainless steels. For this purpose, the ferritic stainless steel X6Cr17 (DIN 1.4016) and the ferritic-austenitic stainless steel X2CrNiMoN22-5-3 (DIN 1.4462) are extruded with an equivalent plastic strain of ε̅ ≈ 1. The research is performed with a molybdenum disulfide (MoS2), a soap and a polymer-based lubricant coating. For reproducing different contact conditions, the die geometry is varied with die opening angles of 60°, 90° and 120°. The suitability of the lubricants is evaluated using the integrity of the lubricant coating after forming. From the correlations between process forces, temperatures and surface integrity, recommendations for the application of the researched lubricants are derived.
Stress/Strain Behaviour of Mechanical and Adhesive Joints in Timber Façade Applications
Authors: Nečasová Barbora , Pavel Liška , Novotný Michal
Published: October 2020

This paper compares the stress and strain behaviour of mechanical fasteners and elastic adhesive connections in timber façade applications. Two common designs with timber cladding are introduced. The traditional façade planks and multilayer large-format solid wood panels were selected. The resistance of a reference façade section with mechanical fasteners or adhesive bond to wind suction is determined according to the recommendations of European guideline ETAG 034. The pressure/suction chamber allowing hermetic closure was used. The sample deformation was measured at 15 locations, this also allowed to determine the elongation of the adhesive layer at break. The failure loads reached with the adhesive joint exceeded 20 kN/m2 in both combinations of façade cladding. On the other hand, the sample with a large-format panel and mechanical fasteners showed the lowest failure load at 12 kN/m2. The results confirmed that bonded joints are a suitable solution for large-format cladding, whereas an increase in the number of mechanical fasteners will be a more convenient solution for façade plank applications.
Effect of Binder Components on the pH of Concrete Mixture with Low pH Intended for Deep Geological Repository for Radioactive Waste in the Czech Republic
Authors: Pernicová Radka , Citek David , Dobiáš Daniel , Kolisko Jiří , Mandlík Tomáš , Hausmannová Lucie
Published: October 2020

This paper deals with the development and research of low pH concrete mixtures intended for the deep geological repository for radioactive waste. Mixtures, in particular those made from materials originating in the Middle Europe, specifically Czech Republic, were designed due to the diversity of the raw materials’ properties. In this first part, a large number of cement mortars were designed, on which the effect of active ingredients (microsilica, slag) on the pH value over time were tested. From the results of the cement mortars’ pH measured after 90 days, a concrete formula was designed. A mixture with a lower proportion of cement and a higher proportion of microsilica seems to be the best. The slag serves only as a supplement in the place value of several weight percent of the total binder volume. Also, the control measurements of basic material characteristics, such as volumetric mass density and compressive strength were performed on these mixtures.
Reconstruction of the Historic Bridge Located in Portz Insel
Authors: Boháčová Denisa , Burgetová Eva
Published: October 2020

The paper presents a structural survey of the arch bridge from the 17th century located in Portz Insel near Mikulov. The purpose of the research was to analyze service life and reliability of the bridge structure including long-term functional durability. There were performed probes in order to search for the original frame foundation and defining a shape of particular arches buried in the ground for decades. The probes also helped to check up the structure of the bridge deck in several places. Currently, throughout 2019 and 2020, the bridge will undergo major reconstruction work in the context of the project „Mikulov, Portz Insel – restructuralisation of the historic countryside“.
Determining Criteria for Assessment of RC Structures Affected by Carbonation-Induced Corrosion
Authors: Mlčoch Jan , Sýkora Miroslav
Published: October 2020

The construction industry is now facing expanding and extensive activities in the area of assessing and retrofitting buildings and bridges that aligns with the sustainable construction strategy. These activities recognise the importance of extending the life of existing construction works thereby delivering environmental, economic and socio-political benefits. Reinforced concrete structures and their reliability are currently receiving considerable attention as a significant part of these structures reaches the design service life. Degradation processes such as carbonation- and chloride-induced corrosion have a major influence on the reliability and serviceability of concrete structures. The submitted study is primarily focused on reinforced concrete structures whose main degradation factor is carbonation of the concrete cover. Examples of such structures are cooling towers or industrial chimneys. Structures in the power industry are usually designed for service life of 40 years. Carbonation-induced corrosion results in visible cracks and unacceptable spalling of concrete cover. The aim of the study is to improve predictions of carbonation-induced corrosion propagation and to critically compare the criteria for degradation level assessment used in practice. The probabilistic analysis is based on measurements of concrete cover and carbonation depths and continuous observations of signs of corrosion on structural surfaces. The example of an industrial chimney shows that the limit of a severe failure, which requires (possibly repeated) minor repairs, is exceeded after about 17 years. The critical failure limit (30% of structural surface with visible signs of corrosion) is reached after 50 years, which seems to be sufficient as it is after 10 years than the usual design service life.
Mechanical Properties of Mortars Based on Roman Cement with the Addition of Power Plant Fly Ash
Authors: Daňková Jana , Majstríková Tereza , Bujdoš David , Mec Pavel
Published: October 2020

Roman cement is a historic hydraulic binder, prepared by firing of limestone with high proportion of clay minerals, usually at temperatures below the sintering point. The firing temperatures of Roman cements range from 800 to 1200°C. At present, this binder is considered to be a promising material with a low carbon footprint and a long lifetime. The properties of Roman cement are influenced by many factors, especially raw materials composition and firing conditions. On the other hand, a disadvantage of mortars based on Roman cement is a slow increase of initial strength. In this paper, the influence of power fly ash admixture on the dynamics of initial strength increase was experimentally investigated. The characteristics of mortars with admixtures were compared with the properties of reference mortar without admixtures. The Roman cement Vicat Prompt TM Natural Cement (manufactured by Vicat SA, French company) was used as a binder. Based on the results of the experiment it can be stated that mortars with the admixture of power plant fly ash show higher dynamics of the increase of initial strengths than the reference mixture.
Sensitivity Assessment of the Nonlinear Resonant Ultrasonic Spectroscopy for Concrete Damage Detection
Authors: Matysík Michal , Plšková Iveta , Chobola Zdeněk
Published: October 2020

Nonlinear Resonant Ultrasound Spectroscopy is a nondestructive acoustic method which is able to measure the bulk hysteretic nonlinearity. This method monitors the shift of the resonant frequency in response of variations in the excitation frequency amplitudes. Measurements were performed on concrete samples exposed to temperatures of 200, 400, 600, 800, 1000, 1200 °C. The elastic modulus values are given to compare the Nonlinear Resonant Ultrasound Spectroscopy (NRUS) sensitivity. These are calculated from the measured velocities of ultrasonic pulses (linear acoustic method) and from the bulk density. The strengths of the samples obtained by destructive methods are also given. Based on these results, the NRUS method can be described as a very sensitive indicator of damage in concrete.
Steel Reinforcement Corrosion - Its Impact on Features of Steel PSC Strand
Authors: Vacek Vítězslav , Kolisko Jiří , Pokorný Petr , Kostelecká Michaela
Published: October 2020

Steel reinforcement made of refined maraging steel in the form of wires and strands has been for a long time used commonly for reinforcement of prestressed concrete structures. Defects on some of them and unfortunately even accidents of some cases of bridge objects, mainly recently published by media, related to corrosion of prestressed reinforcement awoke interest of both professional and wide non-professional public related to its durability. This issue also opens up a question of durability and liability of prestressed structures. In majority of existing prestressed structures the anticorrosion protection of reinforcement was traditionally secured mainly by alkalinity of the environment, i.e. concreting and/or grouting of prestressed elements in ducts. The abstract presents information related mainly to mechanical characteristics of corrosion-affected prestressed elements.
Evaluation of Aggressive Chemicals Effect on CIPP Liners
Authors: Majerová Jana , Hodul Jakub , Drochytka Rostislav , Keprdová Šárka
Published: October 2020

CIPP renovation methods are often used for renovation of sewers and water mains. They can also be used for renovation of gas and product pipelines. However, the presence of chemicals in these pipelines cannot be excluded. For this reason, the ability of CIPP liners to resist chemicals should be examined. This paper deals with problematics of influence of chemicals (acids and bases) on CIPP liners. Visual changes can be observed using an optical microscope. Structural changes are evident from the results of short-term bending tests.
MDA5 Is an Essential Sensor of a Pathogen-Associated Molecular Pattern Associated with Vitality That Is Necessary for Host Resistance against Aspergillus fumigatus
Authors: Wang Xi , Caffrey-Carr Alayna K. , Liu Ko-wei , Espinosa Vanessa , Croteau Walburga , Dhingra Sourabh , Rivera Amariliz , Cramer Robert A. , Obar Joshua J.
Published: October 2020

RIG-I–like receptors (RLR) are cytosolic RNA sensors that signal through the MAVS adaptor to activate IFN responses against viruses. Whether the RLR family has broader effects on host immunity against other pathogen families remains to be fully explored. In this study, we demonstrate that MDA5/MAVS signaling was essential for host resistance against pulmonary Aspergillus fumigatus challenge through the regulation of antifungal leukocyte responses in mice. Activation of MDA5/MAVS signaling was driven by dsRNA from live A. fumigatus serving as a key vitality-sensing pattern recognition receptor. Interestingly, induction of type I IFNs after A. fumigatus challenge was only partially dependent on MDA5/MAVS signaling, whereas type III IFN expression was entirely dependent on MDA5/MAVS signaling. Ultimately, type I and III IFN signaling drove the expression of CXCL10. Furthermore, the MDA5/MAVS-dependent IFN response was critical for the induction of optimal antifungal neutrophil killing of A. fumigatus spores. In conclusion, our data broaden the role of the RLR family to include a role in regulating antifungal immunity against A. fumigatus.
The Militarisation of Conservation and Occupational Violence in Sikumi Forest Reserve, Zimbabwe
Authors: Mushonga Tafadzwa
Published: October 2020

Discussions around the militarisation of conservation have largely focused on violence meted out against subsistence and commercial poachers in, and around, protected areas. Overlooked is violence experienced by perpetrators of such violence. Using lived experiences of anti-poaching in Sikumi Forest Reserve—a state forest managed by Zimbabwe's Forestry Commission—this article examines working experiences of paramilitary personnel. Empirical evidence shows that, in the process of implementing state militarised conservation practices, paramilitary personnel are subjected to violence perpetrated by the state through its authorities. I discuss this violence in the context of occupational violence and make two arguments. The first is that the range of victims of militarised conservation violence goes beyond local communities and commercial poachers to include paramilitary personnel perpetrating such violence. Related to this argument is the second argument that occupational violence has an exacerbating effect on everyday persistent violence. I conclude that aspects of occupational violence, such as displayed in Sikumi Forest Reserve, should be understood as part of broader green violence.
Transient cortical blindness secondary to hepatic encephalopathy in a pediatric patient
Authors: Ain-Nasyrah Ahmad Sukari , Majid Norizan Abdul , Shatriah Ismail
Published: October 2020

Cortical blindness, also known as cerebral visual impairment, may occur in pediatric patients. Hepatic encephalopathy is a rare cause of cortical blindness in children. This report describes a girl with underlying type 1 autoimmune hepatitis, who complained of sudden-onset, painless visual loss in both eyes, which was associated with generalized headache and altered mental status. She was treated with intravenous antibiotics and syrup lactulose. The patient regained full visual recovery after 1 week. Prompt diagnosis and treatment are mandatory in such uncommon instances.
Words of Engel type are concise in residually finite groups. Part II
Authors: Detomi Eloisa , Morigi Marta , Shumyatsky Pavel
Published: October 2020

This work is a natural follow-up of the article [5]. Given a group-word

w

and a group

G

, the verbal subgroup

w(G)

is the one generated by all

w

-values in

G

. The word

w

is called concise if

w(G)

is finite whenever the set of

w

-values in

G

is finite. It is an open question whether every word is concise in residually finite groups. Let

w=w(x_1,\ldots,x_k)

be a multilinear commutator word,

n

a positive integer and

q

a prime power. In the present article we show that the word

[w^q,_ny]

is concise in residually finite groups (Theorem 1.2) while the word

[w,_ny]

is boundedly concise in residually finite groups (Theorem 1.1).