Interaction of Web Spans: Part I—Statics

1989 ◽  
Vol 111 (3) ◽  
pp. 490-496 ◽  
Author(s):  
G. E. Young ◽  
J. J. Shelton ◽  
B. Fang

When the friction between the web and a roller between two web spans is small enough that the tension distribution across the web in the downstream span affects the tension distribution in the upstream span interaction will occur. A model is developed which extends the work of one of the authors to this case and utilizes beam theory which is valid when the web is not in a wrinkled or slack edge state. The boundary conditions and static solutions for the three different types of interaction are established. In the circumferential slippage mode a negative steering effect has been identified. A steering effect description function is established which will allow prediction of this phenomenon which can be avoided by proper choice of system parameters.

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
Sverker Edvardsson ◽  
Tetsu Uesaka

In the present work we propose a particle approach, which is designed to treat complex mechanics and dynamics of the open-draw sections that are still present in many of today’s paper machines. First, known steady-state continuous solutions are successfully reproduced. However, it is shown that since the boundary conditions depend on the solution itself, the solutions for web strain and web path in the open-draw section are generally time-dependent. With a certain set of system parameters, the nonsteady solutions are common. A temporal fluctuation of Young’s modulus, for example, destabilizes the system irreversibly, resulting in the continuous growth of web strain, i.e., break. Finally we exemplify with some strategic draw countermeasures how to prevent a dangerous evolution in the web strain.


2008 ◽  
Vol 75 (3) ◽  
Author(s):  
Peter J. Ryan ◽  
George G. Adams ◽  
Nicol E. McGruer

In beam theory, constraints can be classified as fixed/pinned depending on whether the rotational stiffness of the support is much greater/less than the rotational stiffness of the freestanding portion. For intermediate values of the rotational stiffness of the support, the boundary conditions must account for the finite rotational stiffness of the constraint. In many applications, particularly in microelectromechanical systems and nanomechanics, the constraints exist only on one side of the beam. In such cases, it may appear at first that the same conditions on the constraint stiffness hold. However, it is the purpose of this paper to demonstrate that even if the beam is perfectly bonded on one side only to a completely rigid constraining surface, the proper model for the boundary conditions for the beam still needs to account for beam deformation in the bonded region. The use of a modified beam theory, which accounts for bending, shear, and extensional deformation in the bonded region, is required in order to model this behavior. Examples are given for cantilever, bridge, and guided structures subjected to either transverse loads or residual stresses. The results show significant differences from the ideal bond case. Comparisons made to a three-dimensional finite element analysis show a good agreement.


2019 ◽  
Vol 2 ◽  
pp. 1-8
Author(s):  
Jan Wilkening ◽  
Keni Han ◽  
Mathias Jahnke

<p><strong>Abstract.</strong> In this article, we present a method for visualizing multi-dimensional spatio-temporal data in an interactive web-based geovisualization. Our case study focuses on publicly available weather data in Germany. After processing the data with Python and desktop GIS, we integrated the data as web services in a browser-based application. This application displays several weather parameters with different types of visualisations, such as static maps, animated maps and charts. The usability of the web-based geovisualization was evaluated with a free-examination and a goal-directed task, using eye-tracking analysis. The evaluation focused on the question how people use static maps, animated maps and charts, dependent on different tasks. The results suggest that visualization elements such as animated maps, static maps and charts are particularly useful for certain types of tasks, and that more answering time correlates with less accurate answers.</p>


2022 ◽  
Vol 14 (1) ◽  
pp. 30
Author(s):  
Hazrat Ali ◽  
Md. Kamrujjaman ◽  
Md. Shafiqul Islam

This study proposed a scheme originated from the Galerkin finite element method (GFEM) for solving nonlinear parabolic partial differential equations (PDEs) numerically with initial and different types of boundary conditions. The scheme is applied generally handling the nonlinear terms in a simple way and throwing over restrictive assumptions. The convergence and stability analysis of the method are derived. The error of the method is estimated. In the series, eminent problems are solved, such as&nbsp; Fisher&#39;s equation, Newell-Whitehead-Segel equation, Burger&#39;s equation, and&nbsp; Burgers-Huxley equation to demonstrate the validity, efficiency, accuracy, simplicity and applicability of this scheme. In each example, the comparison results are presented both numerically and graphically


2020 ◽  
Vol 13 (1) ◽  
pp. 79-85
Author(s):  
Caterina Viganò ◽  
Laura Molteni ◽  
Alberto Varinelli ◽  
Calogero Virzì ◽  
Sara Russo ◽  
...  

Background: The technological evolution has given the opportunities to develop new models of education, like online teaching. However, Internet Problematic Use and Internet Addiction are becoming frequently represented among adolescents with a prevalence that varies worldwide from 2% to 20% of the high school population. Objective: The aim of this study was to analyse the risk of Internet Addiction in a High Schools student sample comparing two different types of schools (online and traditional teaching) and analyzing the associations between pathological use of Internet and socio-demographic factors connected to the different educational orientations and to the daily usage of Internet. Methods: Students were enrolled from four different orientation school programs (different high school, technical and economical Institute, vocational schools). Each student completed a self-reported test to collect socio-demographic data and th Internet Addiction Test (IAT) from K. Young to assess the risk of Internet Addiction. The Mann-Whitney test for quantitative variables was used for statistical analysis. Results: 522 students were enrolled, 243 students from online teaching and 279 from traditional teaching schools. Internet Addiction was observed in 1,16% of the total sample, while 53.83% of subjects was at risk of development Internet Addiction. No significant difference was found between the two different types of teaching, nor considering gender. Considering the amount of time spent on the web in portion of the sample at risk of developing Internet Addiction, the Traditional Teaching group spent between 4 and 7 hours a day on the Web, while the Online Teaching group between 1 to 3 hours/daily. However, no statistically significant difference was found. Conclusion: Although our data demonstrate that there is no clear association between online education and problematic use of Internet, the excessive use of Internet is linked to a massive waste of personal energy in terms of time and social life.


Author(s):  
Rabi Pathak

The Formula Student competitions are held everyyear. This paper is the result of the analysis done on the sample car design that can be presented in the Formula Student competition. The purpose of the paper is to provide a final summary on chassis analysis and structural performance. It also talks about all the important analysis that is to be done on a Formula Student car to make it safe and perform well on the track. The design has been made such that it focusses on maximum adjustability, reliability, performance, safety, weight reduction and ease of manufacturing. The analysis was done to make sure the objectives of design are fulfilled. After going through many papers, documents, blogs and videos we found that many people get confused about the loading conditions and boundary conditions for different types of tests so this paper prioritizes to make people understand about those conditions as well as about the major tests required to perform complete analysis of Formula Student cars. The weight of the chassis was calculated as 36 kg approximately according to the data obtained from design modeler of Ansys workbench as well as Solidworks. The design sustained all the loading conditions and passed all the tests. Thus, one of the objective of this paper is to help other universities and passionate students to successfully design and analyze their cars that can pass all necessary tests included in the paper. KEYWORDS—Formula Student; FEA; Boundary Conditions; Loading Conditions; Ansys; Solidworks


1951 ◽  
Vol 18 (2) ◽  
pp. 163-172
Author(s):  
H. D. Conway ◽  
L. Chow ◽  
G. W. Morgan

Abstract This paper presents a method of analyzing the stress distribution in a deep beam of finite length by superimposing two stress functions. The first stress function is chosen in the form of a trigonometric series which satisfies all but one of the boundary conditions—that of zero normal stress on the ends of the beam. The principle of least work is then used to obtain a second stress function giving the distribution of normal stress on the ends which is left by the first stress function. By superimposing the two solutions, all the boundary conditions are satisfied. Two particular cases of a given type of loading are solved in this way to investigate the stresses in a deep beam and their deviation from the ordinary beam theory. In addition, an approximate solution by the numerical method of finite difference is worked out for one of the two cases. Results from the two methods are compared and discussed. A method of obtaining an exact solution to the problem is given in an Appendix.


Author(s):  
Paolo Massa

This chapter discusses the concept of trust and how trust is used and modeled in online systems currently available on the Web or on the Internet. It starts by describing the concept of information overload and introducing trust as a possible and powerful way to deal with it. It then provides a classification of the systems that currently use trust and, for each category, presents the most representative examples. In these systems, trust is considered as the judgment expressed by one user about another user, often directly and explicitly, sometimes indirectly through an evaluation of the artifacts produced by that user or his/her activity on the system. We hence use the term “trust” to indicate different types of social relationships between two users, such as friendship, appreciation, and interest. These trust relationships are used by the systems in order to infer some measure of importance about the different users and influence their visibility on the system. We conclude with an overview of the open and interesting challenges for online systems that use and model trust information.


Author(s):  
Zahid Ashraf Wani ◽  
Huma Shafiq

Nowadays, we all rely on cyberspace for our information needs. We make use of different types of search tools. Some of them have specialization in a specific format or two, while few can crawl a good portion of the web irrespective of formats. Therefore, it is very imperative for information professionals to have thorough understandings of these tools. As such, the chapter is an endeavor to delve deep and highlight various trends in online information retrieval from primitive to modern ones. The chapter also made an effort to envisage the future requirements and expectation keeping in view the ever-increasing dependence on diverse species of information retrieval tools.


Author(s):  
Pankaj Kamthan

In recent years, there has been a steady shift in the nature of Web applications. The vehicle of this transition of Web applications is us, the people. The ability to post photographs or videos, exchange music snippets with peers, and annotate a piece of information, are but a few exemplars of this phenomenon. Indeed, the pseudonym Web 2.0 (O’Reilly, 2005) has been used to describe the apparent “socialization” of the Web. In spite of the significant prospects offered by humancentric Web applications, the mere fact that virtually anyone can set up such applications claiming to sell products and services or upload/post unscrutinized information on a topic as being “definitive,” raises the issues of credibility from a consumers’ viewpoint. Therefore, establishing credibility is essential for an organization’s reputation and for building consumers’ trust. The rest of the article is organized as follows. We first provide the background necessary for later discussion. This is followed by the introduction of a framework within which different types of credibility in the context of human-centric Web applications can be systematically addressed and thereby improved. Next, challenges and directions for future research are outlined. Finally, concluding remarks are given.


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