1,720,961 research outputs found
Differential belt mechanisms for high-precision positioning applications
No full textL'articolo descrive il progetto di due dispositivi a cinghia ad elevata precisione, con cinematica basata su meccanismo differenziale. Questi sistemi possono essere utilizzati in applicazioni "stand-alone" oppure possono essere integrati in architetture più complesse. Il primo dispositivo descritto nell'articolo è un sistema monoasse con elevata velocità ed accelerazione; il secondo è un dispositivo cartesiano che può essere utilizzato come modulo di servizio per una macchina utensile
Soluzioni per la mobilità autonoma di disabili tetraplegici in spostamenti a corto e lungo raggio
No full textAn eco-innovation and technical contaminated approach for designing a low environmental impact off-road motorcycle
No full textWhat does it make some sports such as off-road motorcycle to be perceived as non-environmentally-friendly? Are the activities themselves or the actual and/or traditional way of their fulfillment? How is it possible to make them more environmentally sustainable without giving up the fun? This paper aims to give an answer to these questions, analyzing the case of off-road motorcycling. It is clear that some of negative consequences of such sport are due to the bad behavior and scarce ecological awareness of its practitioners, while it is often neglected that other aspects are related to the present characteristics of its means: the motorcycles. The present work, starting with the analyses of the environmental damages related to this sport, tries to give an answer focusing on the technical aspects of actual motorcycles that can be related to such damages. In particular, the authors propose the application of an integrated eco-innovation and technical contaminated approach for the design and development of a new concept of off-road motorcycle to meet the requirements of low environmental impact and light weight of the vehicle, while maintaining the pleasure of riding in the nature. © 2017 Springer-Verlag Franc
Gölem project: Concept and design of a trekking/hiking wheelchair
No full textThis work concerns the growing interest in accessible tourism and describes the early stages of development of Gölem project. In particular, it takes into account accompanying activities of disabled people in mountain areas. Although literature and market analysis highlight the presence of different technical solutions used for the movement of disabled persons on rough terrains, there are only a couple of solutions based on the help of guides: Joëlette© and TrailRider©. Even if the use of these devices is generally satisfactory, our analysis has highlighted the presence of some limitations such as the difficulty of maintaining the lateral balance of the devices (which involves a considerable physical effort for the guides) and their reduced comfort for the passenger. This article describes the activities developed within the Gölem project. Its main goals are to design and to test an improved model of trekking/hiking wheelchair taking into account passengers comfort and better functionality of the device. At this moment, the design and modeling phases with the definition of dynamic parameters and of the suspension system of the device have been completed. The prototype implementation phase is in progress. Future activities will provide validation and field testing of the new solution with users
In situ compact tensile test device for polymer nanocomposite specimens to be analyzed in an x-ray microdiffractometer
No full textX-ray diffraction is a non-destructive technique for structural analysis of materials. Applications include the evaluation of the residual stresses in real components, wherein the crystalline planes are used as strain gauges. In case of polymer nanocomposites, this technique allows to study the filler structural changes, in particular its orientation as a function of polymer deformation.
A tensile test device to apply uniaxial stretching on polymer nanocomposite specimens has been designed and built to equip a commercial X-ray microdiffractometer.
The main feature of this compact device is allowing setting the specimen strain up to 400% inside the microdiffractometer. X-ray diffraction measurements are carried out at different strains at the same point without removing the sample from the stage. The maximum load applied to the specimen is 100 N.
We report the design phases and the results of preliminary tests on commercial rubber samples
Dental trauma and bicycle safety: A report in Italian children and adolescents
No full textOBJECTIVE:This retrospective study aims to analyze the pattern of oro-facial trauma from bicycle accidents in Italian children and adolescents, focusing on the safety devices used.
METHODS:
The medical records of 1405 patients of the Dental Clinic of the University of Brescia, between the age of 0 to 18, who experienced a dento-facial trauma from the use of a bicycle, were analyzed. Data regarding age, gender, weight, height, dominant hand, type of bicycle, use of safety devices, location and type of dental trauma, teeth involved, bone fractures and soft tissue lesions were recorded. Statistical analysis was performed.
RESULTS:
The majority of the traumatic events occurred in children within the 8-10 years of age-range; 1085 teeth were injured, of which 975 permanent teeth (89.9%) and 110 primary teeth (10.1%). The most common dental lesions were the coronal fractures (complicated and not complicated) while the most frequently involved teeth were the upper central incisors; 11% of patients were also treated for maxillo-facial fractures. A protective helmet was worn only in 3% of the cases; not one patient wore a mouth-guard. The use of helmets was more frequent in children and adolescents riding racing-bikes competitively, compared to those who were mountain bikers (p < 0.05).
CONCLUSIONS:
Bicycle accidents can have serious oro-facial consequences. Therefore, national and regional efforts should be made in Italy to promote head and mouth protection in cycling
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
An integrated acoustic–mechanical development method for off-road motorcycle silencers: from design to sound quality test
No full textVehicle noise is one of the main sources of complaints because it is widespread and active in almost all environments, from urban areas to rural context. The present work aims to describe a practical procedure to design silencers for off-road motorcycles so that, once produced, they are lightweight, do not affect the engine performances and cut noise emissions to a sustainable limit. The required noise reduction, usually around 35–40 dB, can be achieved only by carefully designing the exhaust system. The first part of the paper provides the theoretical background of noise propagation in ducts, describes the main attenuation devices as tools the designer can use in the development process and outlines the workflow. In the second part, a case study of silencer optimization is presented: the noise emitted by a real off-road motorcycle is characterized and, once the sound pressure level and the mass flow generated by the engine are known, a silencer fulfilling noise attenuation, size and pressure drop requirements is designed, 3D-modeled and rendered. The outcome of the acoustic design process can be used to perform virtual sound quality tests, which can be of interest for manufacturers to catch the attention of passionate users
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