Accidental impact by ships in the updated EN 1991-1-7

2021 ◽  
Author(s):  
Claus Kunz
Keyword(s):  
Background Information ◽  
Impact Dynamics ◽  
Impact Mechanics ◽  
2Nd Generation ◽  
Impact Forces ◽  
Final Draft ◽  
Open Questions ◽  
Ship Collision ◽  
Infor Mation ◽  
Load Indentation

<p>Ship collision is still one of the risk-prone expositions for bridges crossing navigable inland and mar- itime waterways. Within the preparation of the 2nd generation of the Eurocodes a 3rd (final) draft of an updated EN 1991-1-7 is edited [2]. Rules and background information for the Eurocode impact rules concerning inland and maritime waterway traffic are given. The rules and recommendations cover aspects like impact dynamics, load-indentation-functions, collision angles, collision probabili- ties and reliability criteria. For seagoing vessels new impact mechanics have been included. Infor- mation from some National Annexes and open questions are mentioned. Examples with determined ship impact forces are presented.</p>

Open Questions in Reverse Mathematics

2011 ◽  
Vol 17 (3) ◽  
pp. 431-454 ◽  
Author(s):  
Antonio Montalbán
Keyword(s):  
Reverse Mathematics ◽  
Background Information ◽  
Open Questions ◽  
Open Question

AbstractWe present a list of open questions in reverse mathematics, including some relevant background information for each question. We also mention some of the areas of reverse mathematics that are starting to be developed and where interesting open question may be found.

Deploying Impact Dynamics Simulation on Deployable Mechanism of Folding Wing with Clearance

2011 ◽  
Vol 211-212 ◽  
pp. 895-899
Author(s):  
Ming Hu ◽  
Miao Miao Zhang ◽  
Wen Hua Chen ◽  
Yong Ping Jin ◽  
Guo Ming Xu ◽  
...  
Keyword(s):  
Impact Force ◽  
Dynamics Simulation ◽  
Impact Dynamics ◽  
Impact Forces ◽  
Adams Software ◽  
Force Variation ◽  
Folding Wing ◽  
Deployable Mechanism ◽  
Set Up ◽  
Two State Model

Based on the non-linear equivalent spring-damper model in the "two-state model", Impact model with hinge clearance for deployable mechanism of folding wing is set up and deploying dynamics on deployable mechanism of folding wing is simulated including impact force variation caused by the size of clearance and the clearance friction by using ADAMS software. The results show that the random continuous impact force is produced by the influence of clearance; as dimensions of the clearance increase, impact times decrease and amplitudes of impact forces are increased; System energy consumption is speeded up and to some extent times of impacts with clearance and disturbance effects of deployable mechanism is suppressed by friction in the whole deployable process.

Impact Forces during Heel-Toe Running

1995 ◽  
Vol 11 (4) ◽  
pp. 407-432 ◽  
Author(s):  
Benno M. Nigg ◽  
Gerald K. Cole ◽  
Gert-Peter Brüggemann
Keyword(s):  
Impact Loading ◽  
Biological Tissue ◽  
Biological Tissues ◽  
Musculoskeletal Injuries ◽  
Future Research ◽  
Noninvasive Techniques ◽  
Impact Mechanics ◽  
Impact Forces ◽  
Running Injuries ◽  
Complex Mechanisms

Impact forces have been speculated to be associated with the development of musculoskeletal injuries. However, several findings indicate that the concepts of “impact forces” and the paradigms of their “cushioning” may not be well understood in relation to the etiology of running injuries and that complex mechanisms may be responsible for injury development during running. The purposes of this paper are (a) to review impact mechanics during locomotion, (b) to review injuries and changes of biological tissue due to impact loading, and (c) to synthesize the mechanical and biological findings. In addition, directions for future research are discussed. Future research should address the development of noninvasive techniques to assess changes in the morphology and biochemistry of bone, cartilage, tendon, and ligaments; researchers should also try to simulate impact loading during activities such as running, focusing on the interaction of the various loading parameters that determine the acceptable windows of loading for biological tissues.

Joint Impact Forces of a Biped Walking on an Uneven Ground

2014 ◽  
Author(s):  
Marzieh Mojaddarasil ◽  
Mohammad Jafar Sadigh
Keyword(s):  
Practical Importance ◽  
Diagnosis And Treatment ◽  
Human Gait ◽  
Impact Dynamics ◽  
Uneven Surface ◽  
Bipedal Robots ◽  
Biped Walking ◽  
Impact Forces ◽  
The Impact

This paper looks into the impact forces applied to the joints of a biped walking on an uneven surface. In this vein, impact dynamics of the swing leg are studied by considering a simple two-link planar manipulator model which comes in contact with the ground. The effect of different parameters and factors on the magnitude of the joint impact forces is investigated. Specifically, it is observed how the elasticity of the shoe, the leg configuration, and the muscular flexibility of the joints affect the joint impact forces. The obtained results can be of practical importance in developing bipedal robots and in the diagnosis and treatment of human gait issues related to joint problems.

Influence of Age, Gender, and Obesity on the Mechanical Properties of the Heel Pad under Walking Impact Conditions

2002 ◽  
Vol 18 (4) ◽  
pp. 345-356 ◽  
Author(s):  
Enrique Alcántara ◽  
Arturo Forner ◽  
Elena Ferrús ◽  
Ana-Cruz García ◽  
José Ramiro
Keyword(s):  
Energy Absorption ◽  
Elderly Women ◽  
The Elderly ◽  
Peak Force ◽  
Peak Displacement ◽  
Impact Mechanics ◽  
Time To Peak ◽  
Heel Pad ◽  
Impact Forces ◽  
Ballistic Pendulum

Impact mechanics of the human heel pad were studied using a ballistic pendulum. Young and elderly men and women took part in the experiment. Twelve parameters were used to describe heel pad properties. Analysis of variance was conducted to assess the influence of age, gender, and obesity. Heel pad properties were correlated with impact force and time to peak force in order to study impact mechanics. Maximal stiffness, peak displacement, and energy absorption were established so as to sufficiently describe impact properties of the heel pad. Age, gender, and obesity introduced significant differences in heel pad properties. Peak displacement and time to peak force increased in the elderly. Women presented a shorter time to peak force together with lower peak displacement, energy absorption, and lower maximal stiffness than men. Obese elderly showed lower impact forces, longer time to peak, and greater peak displacement than non-obese and younger participants. In addition, energy absorption was greater and maximal stiffness was lower for obese than for non-obese participants.

A Mechanical Calculation of the Flexible & Floating Anti-Ship Collision Device for Bridge Piers

2012 ◽  
Vol 479-481 ◽  
pp. 2540-2545
Author(s):  
Wei Lv ◽  
Rui Lin Lu ◽  
Xiang Liang Ning ◽  
Yuan Yuan ◽  
Yu Xin Hu ◽  
...  
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Mechanical Calculation ◽  
Finite Element Software ◽  
Impact Forces ◽  
Collision Processes ◽  
Ship Collision

This study conducts simulation analysis of collision processes between a ship and a pier with the finite element software ABAQUS. It aims to compare peak values of impact forces, stresses and strains of the anti-collision device, and energy changes of the system when with or without the bridge pier protection buffer, so as to verify the device’s role in buffering impact and greatly improving the pier’s resistance to impact.

Passy-Muir Speaking Valve Use in a Children's Hospital: An Interdisciplinary Approach

2008 ◽  
Vol 18 (2) ◽  
pp. 76-86 ◽  
Author(s):  
Lauren Hofmann ◽  
Joseph Bolton ◽  
Susan Ferry
Keyword(s):  
Tracheostomy Tube ◽  
Pediatric Population ◽  
Interdisciplinary Approach ◽  
Extended Period ◽  
Speech Development ◽  
Tube Placement ◽  
Background Information ◽  
Speaking Valve ◽  
Children's Hospital ◽  
Children’S Hospital

Abstract At The Children's Hospital of Philadelphia (CHOP) we treat many children requiring tracheostomy tube placement. With potential for a tracheostomy tube to be in place for an extended period of time, these children may be at risk for long-term disruption to normal speech development. As such, speaking valves that restore more normal phonation are often key tools in the effort to restore speech and promote more typical language development in this population. However, successful use of speaking valves is frequently more challenging with infant and pediatric patients than with adult patients. The purpose of this article is to review background information related to speaking valves, the indications for one-way valve use, criteria for candidacy, and the benefits of using speaking valves in the pediatric population. This review will emphasize the importance of interdisciplinary collaboration from the perspectives of speech-language pathology and respiratory therapy. Along with the background information, we will present current practices and a case study to illustrate a safe and systematic approach to speaking valve implementation based upon our experiences.

Searching Online for Methods of Suicide

Crisis ◽  
2020 ◽  
pp. 1-8
Author(s):  
Christian Ulrich Eriksen ◽  
Flemming Konradsen ◽  
Thilde Vildekilde
Keyword(s):  
Content Analysis ◽  
English Language ◽  
Significant Proportion ◽  
Background Information ◽  
Access To Information ◽  
Online Content ◽  
Negative Effects ◽  
Search Terms ◽  
Methods Of Suicide

Abstract. Background: Information on methods of suicide is available online, and access to information on methods of suicide appears to contribute to a small but significant proportion of suicides. There is limited documentation of how methods of suicide are being profiled, as well as what content exists in other languages than English. Aim: We aimed to analyze and compare how methods of suicide are profiled on Danish and English-language websites. Method: We applied a categorization and content analysis of websites describing methods of suicide. Sites were retrieved by applying widely used Danish and English-language search terms. Results: A total of 136 English-language websites and 106 Danish-language websites were included for analysis. Websites were more often categorized as prevention or support sites, academic or policy sites, and against suicide sites than dedicated suicide sites (i.e., pro-suicide sites), or information sites. However, information on methods of suicide was available, and 20.1% and 8.9% of the English and Danish-language sites, respectively, suggested that a particular method of suicide was quick, easy, painless, or certain to result in death. Limitations: Only one author coded and analyzed all websites. A further operationalization of the content analysis checklist is warranted to increase reliability. Conclusion: The websites primarily had a prevention or anti-suicide focus, but information on methods of suicide was available, requiring an increased focus on how to diminish the negative effects of harmful online content.

What’s Next?

2011 ◽  
Vol 23 (1) ◽  
pp. 60-63 ◽  
Author(s):  
Peter Vorderer
Keyword(s):  
Cultural Differences ◽  
Factor Model ◽  
New Developments ◽  
Theoretical Concepts ◽  
Open Questions ◽  
Entertainment Products ◽  
Entertainment Theory

This paper points to new developments in the context of entertainment theory. Starting from a background of well-established theories that have been proposed and elaborated mainly by Zillmann and his collaborators since the 1980s, a new two-factor model of entertainment is introduced. This model encompasses “enjoyment” and “appreciation” as two independent factors. In addition, several open questions regarding cultural differences in humans’ responses to entertainment products or the usefulness of various theoretical concepts like “presence,” “identification,” or “transportation” are also discussed. Finally, the question of why media users are seeking entertainment is brought to the forefront, and a possibly relevant need such as the “search for meaningfulness” is mentioned as a possible major candidate for such an explanation.

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