DEVELOPMENT OF A MEASUREMENT SYSTEM FOR THE EVALUATION OF KINEMATICS AND IMPACT FORCES IN HISTORICAL FENCING COMBAT

This study aims at evaluating the impact forces acting on the blades of swords during a combat. Such forces will be used as input for numerical simulations to estimate the sword durability. Some replicas of the 17th century swords were instrumented with strain gauges and inertial sensors were placed on athletes’ joints to reconstruct arm kinematic. The forces along the two relevant axes are calculated by linear regression of two Wheatstone bridges and results were consistent with previsions. The calibration showed small uncertainty (max 11 N) with the transverse sensitivity being directly included in calibration parameters. In addition, the system was fully synchronized between all its parts and the bandwidth seems sufficient to calculate the impacts

Germline-encoded neutralization of a Staphylococcus aureus virulence factor by the human antibody repertoire.

Staphylococcus aureus is both an important pathogen and a human commensal. To explore this ambivalent relationship between host and microbe, we analysed the memory humoral response against IsdB, a protein involved in iron acquisition, in four healthy donors. Here we show that in all donors a heavily biased use of two immunoglobulin heavy chain germlines generated high affinity (pM) antibodies that neutralize the two IsdB NEAT domains, IGHV4-39 for NEAT1 and IGHV1-69 for NEAT2. In contrast to the typical antibody/antigen interactions, the binding is primarily driven by the germline-encoded hydrophobic CDRH-2 motifs of IGHV1-69 and IGHV4-39, with a binding mechanism nearly identical for each antibody derived from different donors. Our results suggest that IGHV1-69 and IGHV4-39, while part of the adaptive immune system, may have evolved under selection pressure to encode a binding motif innately capable of recognizing and neutralizing a structurally conserved protein domain involved in pathogen iron acquisition

A reference open data vertical axis wind turbine, with individual pitch control, for code validation purposes

This paper presents the features and capabilities of a vertical axis wind turbine (VAWT) designed and built by the authors, which is meant to be the reference machine for open data code validation purposes under the project VODCA, VAWT Open Data for Code Assessment. The machine, whose design details are provided openly and summarized in the present document, has Individual Pitch Control (IPC) capability and it will be used for wind tunnel tests. Related results will be shared with participants who want to validate their own code, in terms of prediction of the aerodynamics or assessment of IPC strategies. The article reports a comprehensive overview of the state of the art of laboratory tests for VAWTs as well as the motivation of VODCA project, further to the need of code validation against experimental tests in controlled environment. The various phases of the project are also presented. Furthermore, the design of the carbon fiber blades, the structural components, as well as the mechatronics of the machine are summarized in this paper. Moreover, the experimental characterization of the machine's effective capabilities and properties, carried out after the completion of the building process, is reported and then the testing possibilities are defined and discussed

Devolopement of a measurement system for the evaluation of kinematics and impact forces in historical fencing combat

This study aims at evaluating the impact forces acting on the blades of swords during a combat. Such forces will be used as input for numerical simulations to estimate the sword durability. Some replicas of the 17th century swords were instrumented with strain gauges and inertial sensors were placed on athletes’ joints to reconstruct arm kinematic. The forces along the two relevant axes are calculated by linear regression of two Wheatstone bridges and results were consistent with previsions. The calibration showed small uncertainty (max 11 N) with the transverse sensitivity being directly included in calibration parameters. In addition, the system was fully synchronized between all its parts and the bandwidth seems sufficient to calculate the impacts

A Two-Phase Mass Flow Rate Model for Nitrous Oxide Based on Void Fraction

In the field of space propulsion, self pressurized technology is an example of innovation capable of improving system performances through reduction of volumes and other optimizations. Potential applications are widespread and not limited to the propulsion panorama: from on-orbit maneuvering to in-orbit servicing, from refueling of satellites at the end of life to in situ resource exploitation for missions headed towards remote objects of the solar system. However, important drawbacks have been reported for these systems: modeling of fluids and thermal phenomena is complex, thus preventing accurate performance predictions. As a result, no comprehensive and accurate model capable of describing the dynamics of a self-pressurizing propellant tank has been developed so far. In this context, this paper proposes a two-phase mass flow rate model based on void fraction. N2O has been selected due to its use as a green and self-pressurized propellant for in-space propulsive applications. The aim of this paper is to describe the current mass flow rate models present in the literature for this fluid and compare the new model with the one proposed by Dyer. A model validation is also offered, and a test campaign is mentioned. Finally, preliminary results are shown and discussed: results are then compared with the ones obtained through the Dyer model, in order to retrieve a comprehensive comparison among the two simulation frameworks. Comments on the results are added, showing the improvements as well as the limitations of the proposed framework