Form-finding of pierced vaults and digital fabrication of scaled prototype

The new serious consideration to masonry and non-metallic structures evidenced their direct prospective to be, even in the present days, advanced architectural and engineering solutions. In the present paper, a form finding for a cement based tessellated pierced vault is studied. The multi-body rope approach (MRA) was used to define compression-only vault optimal shapes. Successively, the thrust network analysis (TNA) was implemented by Rhino-vault for a further validation of the shape and the definition of different tessellation meshes of the surfaces, according to different hole pattern configuration. Different piercing percentage of the vaults were considered and compared for the best solution identification. In addition, the geometrical solutions were analyzed by means of global stability analysis, taking into account the different positions of the holes. Furthermore, 3D printing with a Fuse Deposition Modeling (FDM) technique in polylactide (PLA) material (completely eco-friendly) is used for the construction of the formworks of the cement based blocks (dowels) useful for the assembly of a vault scaled prototype. The prototype of the vault, characterized by a certain piercing percentage was subjected to different loading conditions and monitored by a non-contact device based on the Digital Image Correlation (DIC) technique. The 3D-DIC was performed to recognize the structural behavior during the loading process of the model (prototype). DIC measurements were used to recognize in advance the critical condition of the vault under loading and the displacement measurements were correlated to the different loading phases up to the collapse condition

Perspective on saffron spice separation based on controlled fluid dynamic system and computer vision

To correctly develop, validate and mass-produce a saffron spice separation machine it is mandatory to particularly know physical and aerodynamics characteristics of the flower. To achieve this goal a wind tunnel is developed by the authors. The data obtained with the wind tunnel are used to get a rough calibration of a fluid dynamic separation device based on the differences of the terminal velocities of the parts that must be separated. To fine-tuning of the machine, a computer-vision system and a controller are developed to automatically adapt the machine parameter following the variability of the saffron spice

Shell and spatial structures: Between new developments and historical aspects

Advanced structural systems are more and more devoted to light, versatile, eco-sustainable structures. This goal can be achieved through the use of new materials and new approaches for structural optimization, form finding, design, and validation. Shell and spatial structures are representative of some of the most efficient structural systems in which the optimized use of materials is combined with effective structural forms and shapes. The ongoing development of analysis methods, design approaches and construction techniques of shell and spatial structures has resulted in an increasing interest from engineers, architects, and builders. This Special Issue is devoted to papers coming from a call principally addressed to the participants of the 1st Italian Workshop on Shell and Spatial Structures (https://sites.google.com/view/iwss2020/home) held online the last June 2020 after the lockdown restriction due to the Covid-19 pandemic (Figure 1). The experience of the first IWSS (IWSS2020) was particularly innovative. It brought together the interests of the Italian and the international community devoted to the study and applications of shell and spatial structures. The IWSS received two significant endorsements, from the IASS (www.iassstructures.org) and from the SISCO (www. siscoscienzadellecostruzioni.org)

Designing a Low-Cost Mechatronic Device for Semi-Automatic Saffron Harvesting

This paper addresses the design of a novel mechatronic device for saffron harvesting. The main proposed challenge consists of proposing a new paradigm for semi-automatic harvesting of saffron flowers. The proposed novel solution is designed for being easily portable with user-friendly and cost-oriented features and with a fully electric battery-powered actuation. A preliminary concept design has been proposed as based on a specific novel cam mechanism in combination with an elastic spring for fulfilling the detachment of the flowers from their stems. Numerical calculations and simulations have been carried out to complete the full design of a proof-of-concept prototype. Preliminary experimental tests have been carried out to demonstrate the engineering feasibility and effectiveness of the proposed design solutions, whose concept has been submitted for patenting

Wear tests on PTFE+pb linings for linear pneumatic actuator guide bushings

Guide bushings for linear actuators are subject to intense mechanical stress and wear, especially when external radial forces are applied. Carrying out simplified wear tests on the materials used in these bushings is important in making it possible to estimate how many cycles the actuator can perform before the bushing must be replaced. This paper presents the results of tribological pin-on-disk testing on an anti-friction lining consisting of a porous bronze sinter impregnated and coated with PTFE+Pb. Test specimens were worn with a steel ball, and wear and friction coefficients were determined experimentally with increasing loads and speeds

Design and preliminary testing of a novel semi-automatic saffron harvesting device

This paper addresses the procedure for designing a novel mechatronic device for a semi-automatic saffron harvesting. The design process includes the kinematic analysis and synthesis of the proposed mechanism to fulfill a grasping and harvesting of saffron flower with a specific two-finger gripper design. Then, a cam mechanism and elastic spring elements are designed to provide a shaking movement that achieves the splitting of the flower from its steam and a consequent flower harvesting. This is followed by a suction system for collecting and storing the harvested flowers. A 3D printed prototype is reported and preliminarily tested for validating the engineering feasibility and effectiveness of the proposed design solution

Acoustic Emission Monitoring of the Syracuse Athena Temple: Scale Invariance in the Timing of Ruptures

We perform a comparative statistical analysis between the acoustic-emission time series from the ancient Greek Athena temple in Syracuse and the sequence of nearby earthquakes. We find an apparent association between acoustic-emission bursts and the earthquake occurrence. The waiting-time distributions for acoustic-emission and earthquake time series are described by a unique scaling law indicating self-similarity over a wide range of magnitude scales. This evidence suggests a correlation between the aging process of the temple and the local seismic activit

A Saffron Spice Separation System with Computer Vision

A separation device is described to obtain saffron spice after harvesting. To set the separation device, a vertical wind tunnel is developed which measures the terminal velocities of parts of saffron flower, with variations for different regions and years of production. The separation device is equipped with a vision system, which evaluates the separation and the percentage of purity of the saffron spice obtained after separation. In this paper, the design and the realization of the wind tunnel and of the separation device are described and the separation of the flower is performed and discussed, evaluating the separation efficiency