Distribution of Longitudinal Forces in the Body of Passenger Trains

2015 ◽  
Vol 809-810 ◽  
pp. 1175-1180 ◽  
Author(s):  
Camil Ion Crăciun ◽  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Mechanical Model ◽  
Rigid Bodies ◽  
The Body ◽  
Nonlinear Characteristic ◽  
Braking System ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Passenger Trains ◽  
Over Time

The distribution and the size of longitudinal dynamic forces that develop in the train body found in braking system are influenced by the length of the train. To determine these forces, it is used a mechanical model consisting of rigid bodies, representing the train vehicles, connected by elastic and damping elements with the nonlinear characteristic that shapes the buffer and draw-gear. The results based on numerical simulations highlight the emergence of dynamic longitudinal forces during braking, their evolution over time and the distribution of maximum compression and stretching forces that develop in buffer and draw-gear devices, for different lengths of the passenger train.

About Longitudinal Dynamics of Classical Passenger Trains during Braking Actions

2013 ◽  
Vol 378 ◽  
pp. 74-81 ◽  
Author(s):  
Cătălin Cruceanu ◽  
Camil Ion Crăciun
Keyword(s):  
Traffic Safety ◽  
Numerical Examples ◽  
Longitudinal Dynamics ◽  
Braking System ◽  
Dynamic Forces ◽  
Passenger Trains

There are presented and analyzed specific aspects regarding the main mechanic and pneumatic issues determining the in-train dynamic forces developed during braking actions. Particularities in case of passenger trains are highlighted, with the aim of proving that even in the case of short trains, fitted with UIC type P braking system, longitudinal dynamics can cause significant reactions whose effect cannot be neglected, both in terms of traffic safety and comfort. Numerical examples presented stand for this.

scholarly journals Influence of resistance to motion of railway vehicles on the longitudinal trains dynamics

2018 ◽  
Vol 178 ◽  
pp. 06003
Author(s):  
Camil Crăciun ◽  
Cătălin Cruceanu
Keyword(s):  
The Body ◽  
Simulation Program ◽  
Longitudinal Dynamics ◽  
Railway Vehicles ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Braking Process

Longitudinal dynamics of trains is a subject that generates discussions and views on the parameters that interfere and influence both the size of the forces and their distribution in the train body. The paper is a study to determine the influence of resistances to motion on the longitudinal dynamic forces that develop in the body of the train in the braking process. For this, a train study model of ten identical vehicles, to which the locomotive may or may not be attached, is adopted. Initially, the simulation program for the non-locomotive model is run in two variants: with and without introducing additional resistances to motion, followed by the same simulations but with the locomotive introduced and a wagon removed, thus the number of vehicles remains the same for all the cases presented.

scholarly journals The prevalence of underweight in 9–10-year-old schoolchildren in Liverpool: 1998–2006

2009 ◽  
Vol 12 (7) ◽  
pp. 953-956 ◽  
Author(s):  
Lynne M Boddy ◽  
Allan F Hackett ◽  
Gareth Stratton
Keyword(s):  
Mass Spectrum ◽  
Body Mass ◽  
The Body ◽  
Fitness Testing ◽  
Policy Makers ◽  
Substantial Problem ◽  
Prevalence Of Obesity ◽  
Grade 3 ◽  
The City ◽  
Over Time

AbstractObjectiveTo estimate the prevalence of underweight between 1998 and 2006 in Liverpool schoolchildren aged 9–10 years using recently published underweight cut-off points.Design and settingStature and body mass data collected at the LiverpoolSportsLinx project’s fitness testing sessions were used to calculate BMI.SubjectsData were available on 26 782 (n13 637 boys, 13 145 girls) participants.ResultsOverall underweight declined in boys from 10·3 % in 1998–1999 to 6·9 % in 2005–2006, and all sub-classifications of underweight declined, in particular grade 3 underweight, with the most recent prevalence being 0·1 %. In girls, the prevalence of underweight declined from 10·8 % in 1998–1999 to 7·5 % in 2005–2006. The prevalence of all grades of underweight was higher in girls than in boys. Underweight showed a fluctuating pattern across all grades over time for boys and girls, and overall prevalence in 2005–2006 represents over 200 children across the city.ConclusionsUnderweight may have reduced slightly from baseline, but remains a substantial problem in Liverpool, with the prevalence of overall underweight being relatively similar to the prevalence of obesity. The present study highlights the requirement for policy makers and funders to consider both ends of the body mass spectrum when fixing priorities in child health.

scholarly journals Detection of Acetaminophen and Its Glucuronide in Fingerprint by SALDI Mass Spectrometry Using Zeolite and Study of Time-Dependent Changes in Detected Ion Amount

Analytica ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 66-75
Author(s):  
Toshiki Horikoshi ◽  
Chihiro Kitaoka ◽  
Yosuke Fujii ◽  
Takashi Asano ◽  
Jiawei Xu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Glucuronic Acid ◽  
Laser Desorption ◽  
The Body ◽  
Time Dependent ◽  
Laser Desorption Ionization ◽  
Fingerprint Analysis ◽  
Desorption Ionization ◽  
Acid Conjugate ◽  
Over Time

The ingredients of an antipyretic (acetaminophen, AAP) and their metabolites excreted into fingerprint were detected by surface-assisted laser desorption ionization (SALDI) mass spectrometry using zeolite. In the fingerprint taken 4 h after AAP ingestion, not only AAP but also the glucuronic acid conjugate of AAP (GAAP), caffeine (Caf), ethenzamide (Eth), salicylamide (Sala; a metabolite of Eth), and urea were detected. Fingerprints were collected over time to determine how the amounts of AAP and its metabolite changed with time, and the time dependence of the peak intensities of protonated AAP and GAAP was measured. It was found that the increase of [GAAP+H]+ peak started later than that of [AAP+H]+ peak, reflecting the metabolism of AAP. Both AAP and GAAP reached maximum concentrations approximately 3 h after ingestion, and were excreted from the body with a half-life of approximately 3.3 h. In addition, fingerprint preservation was confirmed by optical microscopy, and fingerprint shape was retained even after laser irradiation of the fingerprint. Our method may be used in fingerprint analysis.

scholarly journals B-Spline Impulse Response Functions of Rigid Bodies for Fluid-Structure Interaction Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
S. Zhou-Bowers ◽  
D. C. Rizos
Keyword(s):  
Impulse Response ◽  
Dynamic Models ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Rigid Bodies ◽  
The Body ◽  
Impulse Response Functions ◽  
Fluid Structure ◽  
B Spline ◽  
Structure Interaction

Reduced 3D dynamic fluid-structure interaction (FSI) models are proposed in this paper based on a direct time-domain B-spline boundary element method (BEM). These models are used to simulate the motion of rigid bodies in infinite or semi-infinite fluid media in real, or near real, time. B-spline impulse response function (BIRF) techniques are used within the BEM framework to compute the response of the hydrodynamic system to transient forces. Higher-order spatial and temporal discretization is used in developing the kinematic FSI model of rigid bodies and computing its BIRFs. Hydrodynamic effects on the massless rigid body generated by an arbitrary transient acceleration of the body are computed by a mere superposition of BIRFs. Finally, the dynamic models of rigid bodies including inertia effects are generated by introducing the kinematic interaction model to the governing equation of motion and solve for the response in a time-marching scheme. Verification examples are presented and demonstrate the stability, accuracy, and efficiency of the proposed technique.

scholarly journals On rolling friction

2019 ◽  
Vol 485 (3) ◽  
pp. 295-299
Author(s):  
A. P. Ivanov
Keyword(s):  
Friction Coefficient ◽  
Angular Velocity ◽  
Viscous Friction ◽  
Rolling Friction ◽  
The Body ◽  
Normal Velocity ◽  
Contact Conditions ◽  
Combined Motion ◽  
Pure Rolling ◽  
Over Time

The dependence of rolling friction on velocity for various contact conditions is discussed. The principal difference between rolling and other types of relative motion (sliding and spinning) is that the points of the body in contact with the support change over time. Due to deformations, there is a small contact area and, entering into contact, the body points have a normal velocity proportional to the diameter of this area. For describing the dependence of the friction coefficient on the angular velocity in the case of “pure” rolling, a linear dependence is proposed that admits a logical explanation and experimental verification. Under the combined motion, the rolling friction retains its properties, the sliding and spinning friction acquiring the properties of viscous friction.

scholarly journals Impact of Baseline BMI upon the Success of Latina Participants Enrolled in a 6-Month Physical Activity Intervention

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Sheri J. Hartman ◽  
Shira I. Dunsiger ◽  
Dori W. Pekmezi ◽  
Brooke Barbera ◽  
Charles J. Neighbors ◽  
...  
Keyword(s):  
Physical Activity ◽  
Cognitive Processes ◽  
Physical Activity Intervention ◽  
The Body ◽  
Physical Activity Interventions ◽  
Family Social Support ◽  
Longitudinal Regression ◽  
Baseline Bmi ◽  
The Relationship ◽  
Over Time

High rates of obesity in Latinas highlight the need to determine if physical activity interventions are equally effective across the body mass index (BMI) range. Thus, this study assessed how BMI impacts success of Spanish-speaking Latinas in a culturally and linguistically adapted theory-based physical activity intervention (). Longitudinal regression models tested the relationship between baseline BMI and outcomes. Overall, a trend for a negative association was found between baseline BMI and self-reported physical activity and theoretical constructs targeted by the intervention over time. For example, someone with a 25 kg/m2BMI would report, on average, 27.5 more minutes/week of activity compared to someone with a 30 kg/m2BMI at followup. Furthermore, higher baseline BMI was significantly associated with lower self-efficacy, behavioral and cognitive processes of change, and family social support over time. These findings suggest that participants with higher BMI may need additional intervention to promote physical activity.

Assessing IPR Disclosure within Standard Setting

2015 ◽  
pp. 86-105 ◽  
Author(s):  
Anne Layne-Farrar
Keyword(s):  
The Body ◽  
The Other ◽  
Mobile Telephony ◽  
Publication Date ◽  
Patent Holder ◽  
Policy Changes ◽  
Policy Issues ◽  
Full Knowledge ◽  
Over Time

As part of its “policy project to examine the legal and policy issues surrounding the problem of potential patent ‘hold-up' when patented technologies are included in collaborative standards,” the Federal Trade Commission held an all-day workshop on June 21, 2011. The first panel of the day focused on patent disclosure rules intended to encourage full knowledge of patents “essential” for a standard and therefore to prevent patent ambush. When patents are disclosed after a standard is defined, the patent holder may have enhanced bargaining power that it can exploit to charge excessive royalties (e.g., greater than the value the patented technology contributes to the product complying with the standard). In this chapter, the authors present a case study on patent disclosure within the ICT sector. Specifically, they take an empirical look at the timing of patent disclosures within the European Telecommunications Standards Institute, the body responsible for some of the world's most prevalent mobile telephony standards. They find that most members officially disclose their potentially relevant patents after the standard is published, and sometimes considerably so. On the other hand, the authors also find that the delay in declaring patents to ETSI standards has been shrinking over time, with disclosures occurring closer to (although for the most part still after) the standard publication date for more recent standard generations as compared to earlier ones. This latter finding coincides with ETSI policy changes, suggesting that standards bodies may be able to improve patent disclosure with more precise rules.

A Semi-Discrete Approach for the Numerical Simulation of Freestanding Blocks

2016 ◽  
pp. 416-439
Author(s):  
Fernando Peña
Keyword(s):  
Differential Equation ◽  
Numerical Simulation ◽  
Numerical Modeling ◽  
Discrete Model ◽  
Mathematical Formulation ◽  
Equation Of Motion ◽  
Rigid Bodies ◽  
The Body ◽  
Discrete Approach ◽  
Rocking Motion

This chapter addresses the numerical modeling of freestanding rigid blocks by means of a semi-discrete approach. The pure rocking motion of single rigid bodies can be easily studied with the differential equation of motion, which can be solved by numerical integration or by linearization. However, when we deal with sliding and jumping motion of rigid bodies, the mathematical formulation becomes quite complex. In order to overcome this complexity, a Semi-Discrete Model (SMD) is proposed for the study of rocking motion of rigid bodies, in which the rigid body is considered as a mass element supported by springs and dashpots, in the spirit of deformable contacts between rigid blocks. The SMD can detect separation and sliding of the body; however, initial base contacts do not change, keeping a relative continuity between the body and its base. Extensive numerical simulations have been carried out in order to validate the proposed approach.

How Is Watching Done?

2022 ◽  
pp. 64-80
Keyword(s):  
The Body ◽  
Visual Process ◽  
Primary Mechanism ◽  
Over Time

The process of surveillance has changed over time, as the object of surveillance—the narratives—have evolved. The primary mechanism of surveillance involved studying the analog body by watching the activities that the body performed. As such, the visual process, using cameras of different capabilities, has been a key way for watching. With the increasing digitization, the watching has relied on methods that capture the data about institutions and people.

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