Compression modes in nuclei: microscopic models with Skyrme interactions

The isoscalar giant monopole resonances (ISGMR) and giant dipole resonances (ISGDR) in medium-heavy nuclei are investigated in the framework of HF+RPA and HF-BCS+QRPA with Skyrme effective interactions. It is found that pairing has little effect on these modes. It is also found that the coupling of the RPA states to 2p-2h configurations results in about (or less than) 1 MeV shifts of the resonance energies and at the same time gives the correct total widths. For the ISGMR, comparison with recent data leads to a value of nuclear matter compression modulus close to 215 MeV. However, a discrepancy between calculated and measured energies of the ISGDR in $^{208}$Pb is found and remains an open problem.Comment: To appear in: ``RIKEN Symposium and Workshop on Selected Topics in Nuclear Collective Excitations'', proceedings of the meeting, RIKEN, Wako city (Japan), March 20--24, 199

Using Old Schröder-Reuleaux Models in Modern Kinematics Lectures

The paper deals with the use for educational purposes of kinematic models of the Schroder/Reuleax collection preserved at the Department of Mechanical and Aerospace Engineering of Politecnico di Torino. The article first traces a brief history of the models, which were acquired at the end of the 19th C. by the Regio Museo Industriale of Turin. Four straight-line mechanisms of the collection, employed in modern kinematics lectures, are presented in detail. The didactic method adopted starts from the analysis of the models of the collection and leads the students to develop schemes and software models, in a process of transition from real to virtual. The simulation results are then interpreted and correlated with the functioning of the real model

Prototyping of manual wheelchair with alternative propulsion system

Aim: This paper presents the study, design and prototyping of a manual wheelchair, named handwheelchair.q, with an innovative propulsion's system. The research is based on a novel system of propulsion that is more efficient and ergonomic than the hand rim one. The main goal of the designed prototype is to facilitate the mobility and to extend the reachable areas while reducing the required time. Methods: The propulsion is realised through a rowing-inspired gesture. Results: This gesture avoids the damages caused on shoulders by the compressive force of the hand rim and lever systems. Conclusion: The prototyping allowed the analysis of the project parameters and their influence on the kinematic characteristics of the prototype and the biomechanical characteristics of the gesture. The same propulsion's system can be adopted on wheelchairs devoted to sport activities, representing the starting point for a future prototype of racing wheelchairs. In this regard, the wheelchair's braking system has been redesigned in order to improve efficiency and safety.Implication for rehabilitation The use of the Handwheelchair.q may have positive impacts in terms of the quality of life, in order to reduce the shoulder pain caused by the handrim and lever system. In addition, it can be a good tool for rehabilitation because the activity can be performed outdoor

Autonomous detection and ascent of a step for an electric wheelchair

With the number of individuals using a wheelchair on the rise, the issue of removing architectural barriers, or at least overcoming them, has to be faced to improve independence, inclusiveness, and participation of wheelchair users. Some electric wheelchairs can climb and descend stairs and obstacles, however, the actual operations required to do so safely may be complex and may require an experienced or trained user. To overcome this issue, a method to first detect and classify a step and then autonomously climb it safely is proposed here. The same method is then applied and tested on an actual stair-climbing wheelchair prototype to prove its reliability in different conditions

Stair-climbing wheelchair.q05: from the concept to the prototype

In this paper, an electric stair-climbing wheelchair, named wheelchair.q05, able to move on flat ground and to climb stairs, is presented. The proposed solution has been developed through a series of studies and designs, all based on a smart hybrid triple leg-wheel locomotion unit. The stability of the device is guaranteed by a rear support of a pair of pivoting wheels during motion on flat ground, and by the support of an idle track, when climbing on or going down stairs. By means of mechanisms and actuators, it is possible to change the configuration of the wheelchair, from the flat ground motion to the stair climbing configuration

The design of a new manual wheelchair for sport

In this paper, an innovative system of propulsion inspired by a rowing gesture for manual wheelchairs is shown. The innovative system of propulsion, named Handwheelchair.q, can be applied to wheelchairs employed in everyday life and to sports wheelchairs for speed races, such as Handbike and Wheelchair racing. The general features of the innovative system of propulsion and the functional designs of the different solutions are described in detail. In addition, the design of the mechanism for the transmission of motion, employed in a second prototype, Handwheelchair.q02, is presented and analysed. Finally, the dynamic model of the Handwheelchair.q has been developed in order to obtain important results for the executive design of Handwheelchair.q

Float-Ram: A Sustainable Machine for Buildings Made by Compressed Earth Blocks

This article describes a sequence of research, design, prototyping and utilization of a new manually operated press, which has the purpose of facilitating a construction technology that uses compressed earth blocks, CEB. Buildings and houses made of CEB have better quality than traditional in poor region. They are also economical, robust, aesthetically pleasing, and sustainable from an environmental point of view. The research is addressed to some targets of the SDG 11, Sustainable Cities and Communities: (i) “ensure access for all to adequate, safe and affordable housing and basic services and upgrade slums”; (ii) “support least developed countries, including through financial and technical assistance, in building sustainable and resilient buildings utilizing local materials”. The paper presents the project path, the results and finally the impact in a specific context, the rural areas in Tanzania