Search results for "motion"

A stepper motor-driven microelectrode positioner

1987

The mechanical elements and the electronic control system from a stepper motor-driven microelectrode positioner is described. The unit embodies a high-precision small step angle hybrid motor. The compact, rugged and totally concentric design of the mechanic, by a spindle mechanism achieves the necessary precision by translating the stepwise rotations of the motor into steps of linear movement. The system takes advantage of commercially available low friction parts such as ball bearings, ball bushings and axles with hardened surfaces. The related electronic control unit is designed around the most recent integrated circuitry which is both sophisticated and economical. Though the described sy…

Novel Concept for Electro-Hydrostatic Actuators for Motion Control of Hydraulic Manipulators

2021

Self-contained hydraulic cylinders have gained popularity in the recent years but have not been implemented for high power articulated hydraulic manipulators. This paper presents a novel concept for an electro-hydrostatic actuator applicable to large hydraulic manipulators. The actuator is designed and analyzed to comply with requirements such as load holding, overload handling, and differential flow compensation. The system is analyzed during four quadrant operation to investigate energy efficiency and regenerative capabilities. Numerical simulation is carried out using path control and 2DOF anti-swing of a hydraulic crane as a load case to illustrate a real world scenario. A comparison wi…

Generation of radiative knots in a randomly pulsed protostellar jet

2009

HH objects are characterized by a complex knotty morphology detected mainly along the axis of protostellar jets in a wide range of bands. Evidence of interactions between knots formed in different epochs have been found, suggesting that jets may result from the ejection of plasma blobs from the source. We aim at investigating the physical mechanism leading to the irregular knotty structure observed in jets in different bands and the complex interactions occurring among blobs of plasma ejected from the stellar source. We perform 2D axisymmetric HD simulations of a randomly ejected pulsed jet. The jet consists of a train of blobs which ram with supersonic speed into the ambient medium. The in…

From Planning to Management of Cultural Heritage Sites: Controversies and Conflicts Between Unesco WHL Management Plans and Local Spatial Planning in…

2014

The paper investigates the relationship between the preservation of cultural heritage and planning in UNESCO World Heritage List (WHL) sites, with special reference to the relation be- tween Management Plans and other (local and regional) planning instruments and policies able to influence the promotion of sustainable and responsible development. This will be explored through a case study related to South-Eastern Sicilian UNESCO sites (in particular Syracuse). The analysis of this case study will point out the challenge of integrating different management and planning regimes - which mainly refer to a performative model - in a (still) very conformative planning sys- tem. The paper will show…

Guilt and Media Use

2020

La promoción de la actividad física en el lugar de trabajo: demanda de actividad física en dos mercados madrileños. (Promotion of physical activity a…

2009

Promotion of physical activity at the worksite is part of the global strategies for health promotion. The introduction of physical activity programs at worksites requires an analysis of the current demand in specific contexts. This study analyzes the demand of physical activity among workers at two markets in Madrid: "Maravillas" and "Las Aguilas". It is hypothesized that in both markets latent demand (people that do not practice physical activity but are wishing to do so) prevails over actual demand (people that already practice physical activity) and absent demand (people that do not practice physical activity and do not wish to do so). Results show that this hypothesis is fulfilled at "M…

Visually induced motion sickness and presence in videogames: The role of sound

2012

Visually induced motion sickness (VIMS) is a well-known phenomenon in virtual environments, simulators, and videogames. We conducted an experiment to analyze the role of sound on the severity of VIMS and the feeling of presence in videogames. Thirty-two subjects first watched a pre-recorded sequence of the game “Mirrors Edge” and then played the game actively. Game-play sound was activated for half of the participants. VIMS was measured via the Simulator Sickness Questionnaire and the Fast Motion Sickness Scale, presence was captured using the Presence Questionnaire. Results showed severe VIMS in all participants during the passive video session, whereas active-play revealed only moderate …

The (controversial) role of the UNESCO WHL Management Plans in promoting sustainable tourism development

2012

This paper investigates the relationship between tourism and planning in UNESCO World Heritage List (WHL) sites. It concentrates on the relation between Management Plans (MPs) and other (local and regional) planning instruments and policies able to influence the promotion of sustainable and responsible development. This is explored through an examination of two important tourist locations in Sicily: Agrigento (the Valley of the Temples) and the Aeolian Islands, which have both been recognized as World Heritage Sites by UNESCO. The analysis of these case studies will point out the challenge of integrating different management and planning regimes. The paper shows how supranational policies o…

Diferenças de sexo no uso de estratégias de enfrentamento em pessoas com lesão medular

2017

12 Páginas Objetivo: profundizar en la experiencia de afrontamiento en personas con lesión medular (LM), teniendo en cuenta tanto el afron- tamiento actual como el afrontamiento durante momentos iniciales tras sufrir la LM. Materiales y métodos: estudio transversal de encuesta. Participaron 127 personas con LM de larga evolución, 95 hombres y 32 mujeres. Los datos fueron recogidos por medio de un cuestionario online con información sociodemográfica y el Cuestionario de Afrontamiento del Estrés (CAE). Se han realizado análisis descriptivos, pruebas t de Student y análisis multivariados de la varianza (Manovas) Resultados: las comparaciones intrasujetos muestran que la estrategia de focalizac…

Systèmes imageurs 3D pour des applications agricoles : caractérisation de cultures et phénotypage de racines

2016

The development of the concepts of precision agriculture and viticulture since the last three decades has shown the need to use first 2D image acquisition techniques and dedicated image processing. More and more needs concern now 3D images and information. The main ideas of this chapter is thus to present some innovations of the 3D tools and methods in the agronomic domain. This chapter will particularly focus on two main subjects such as the 3D characterization of crop using Shape from Focus or Structure from Motion techniques and the 3D use for root phenotyping using rhizotron system. Results presented show that 3D information allows to better characterize crucial crop morphometric parame…