General Terms of Metal Forming Grundbegriffe der Metallbearbeitung Nozioni fondamentali della formatura dei metalli

Author(s):  
Keyword(s):  
Author(s):  
R. H. Wagoner ◽  
J.-L. Chenot

Author(s):  
Е. А. Фролов ◽  
В. В. Агарков ◽  
С. И. Кравченко ◽  
С. Г. Ясько

To determine the accuracy of the readjustable punches for separating operations (perforation + punching out) of sheet-metal forming, the accuracy parameters were analyzed using the random balance method using the method of experiment planning. Analytical dependencies are obtained to determine the values of deviation of the outer and inner contour dimensions of perforated and punched out sheet parts. From the dependencies obtained, it is possible to estimate and predict the value of deviation in the dimensions of the resulting part at any time during the operation of the punch. Practical recommendations on the calculation of the actuating dimensions of the working elements (stamping punch, matrix) of readjustable punches are offered.


Author(s):  
Markus Krötzsch

To reason with existential rules (a.k.a. tuple-generating dependencies), one often computes universal models. Among the many such models of different structure and cardinality, the core is arguably the “best”. Especially for finitely satisfiable theories, where the core is the unique smallest universal model, it has advantages in query answering, non-monotonic reasoning, and data exchange. Unfortunately, computing cores is difficult and not supported by most reasoners. We therefore propose ways of computing cores using practically implemented methods from rule reasoning and answer set programming. Our focus is on cases where the standard chase algorithm produces a core. We characterise this desirable situation in general terms that apply to a large class of cores, derive concrete approaches for decidable special cases, and generalise these approaches to non-monotonic extensions of existential rules.


2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Yoan Martínez Márquez ◽  
Yalice Gámez Batista ◽  
Norberto Valcárcel Izquierdo

Las TIC median las interacciones y la comunicación de los estudiantes a diario. Se conciben como mediado-ras de la reflexión y la autorregulación de la actividad del estudiante, resultante de la interacción consciente de la percepción que tiene el estudiante sobre si con la que negocia con el resto de los estudiantes, los ase-sores y la sociedad en general. En este contexto el aprovechamiento de las TIC debe promover una influen-cia formativa en los espacios formales y no formales. Las condicionantes de complementariedad de espa-cios y de unidad en la diversidad de recursos tecnológicos y didácticos deben guiar la actividad que tenga al estudiante como centro de la misma.Ya no se trata de integrar las TIC en el proceso de formación, haciéndolo formal y estandarizado. El reto está en que sean las características personales de los estudiantes, sus estilos de aprendizaje, sus conoci-mientos y experiencias previas, y sus esquemas afectivos los que marquen el aprovechamiento de las TIC en la evaluación del aprendizaje autónomo de inglés.En el presente trabajo se estructura el aprovechamiento de las TIC mediante un EPA base para la evalua-ción del aprendizaje autónomo de inglés. El EPA base constituye un andamiaje de personas, procedimien-tos, espacios de interacción, y de recursos tecnológicos y didácticos. Los componentes que lo conforman se encuentran débilmente acoplados por la tecnología y altamente cohesionados por la significatividad de las conexiones que el estudiante establece entre ellos. Palabras Clave: Aprendizaje, Autonomía, Entorno, Evaluación, Personal. ABSTRACT There is no doubt about the key role of ICT in the interaction and communication processes among students. ICT are thought as a mean for the reflection and self-regulation of students´ activity, which is in a permanent conscientious comparison between the perception a student has about him/herself and the one he/she nego-tiates with the rest of students, advisors and society in general terms. In this context, ICT should promote a positive influence on student formation in formal and non-formal spaces. The conditionals related to spaces combined support and union in the diversity of technological and didactical resources should guide every activity having students at the center of its conception.It is no longer about integrating ICT to the formation process making it formal and standardized. The chal-lenge on autonomous language learning evaluation with ICT has to do with making the differences through personal characteristics of students, their learning styles, previous experiences and affective schemas.In this paper the use of ICT is structured by means of a PLE frame for the evaluation of English autonomous language learning. It is a scaffolding of people, procedures, interaction spaces, and technological and didac-tical resources. Its components are weakly coupled by technologies and highly cohesive by the meaningful connections students establish among them. Keywords: Learning, Autonomy, Evaluation, Environment, Personal. Recibido: septiembre de 2016Aprobado: noviembre de 2016


2020 ◽  
Author(s):  
Xiangwen Wang ◽  
Dimitrios Toroz ◽  
Seonmyeong Kim ◽  
Simon Clegg ◽  
Gun-Sik Park ◽  
...  

<div> <p>As natural aqueous solutions are far from being pure water, being rich in ions, the properties of solvated ions are of relevance for a wide range of systems, including biological and geochemical environments. We conducted ab initio and classical MD simulations of the alkaline earth metal ions Mg<sup>2+</sup> and Ca<sup>2+</sup> and of the alkali metal ions Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup> and Cs<sup>+</sup> in pure water and electrolyte solutions containing the counterions Cl<sup>–</sup> and SO<sub>4</sub><sup>2–</sup>. Through a detailed analysis of these simulations, this study reports on the effect of solution chemistry (composition and concentration of the solution) to the ion–water structural properties and interaction strength, and to the dynamics, hydrogen bond network, and low-frequency dynamics of the ionic solvation shell. Except for the ion–water radial distribution function, which is weakly dependent on the counter-ions and concentrations, we found that all other properties can be significantly influenced by the chemical characteristics of the solution. Calculation of the velocity autocorrelation function of magnesium ions, for example, shows that chlorine ions located in the second coordination shell of Mg<sup>2+</sup> weaken the Mg(H<sub>2</sub>O)<sub>6</sub><sup>2+</sup> hydration ‘cage’ of the cation. The result reported in this study suggest that ionic solvation shell can be significantly influenced by the interactions between other ions present in solution ions, especially those of opposite charge. In more general terms, the chemical characteristics of the solution, including the balance between ion-solvent and ion-ion interactions, could result in significant differences in behavior and function of the ionic solvation shell.</p> </div>


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