X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information nee...

https://www.tandfonline.com/doi/pdf/10.1179/1743280413Y.0000000023

Quantitative X-ray tomography

Sustainability is a pressing concern of the 21st century. Social development in most countries is raising awareness of the needs of future generations and legislation to protect the present and future quality of life. These needs are compelling various sectors, including construction, to find sustainable solutions. This paper investigates the feasibility of incorporating high-quality recycled concrete aggregates in new concrete, providing a recycling option for precast rejects. The massification of recycled aggregate incorporation would decrease the environmental impacts of the concrete industry, for instance due to reduced landfill disposals, less quarry mining and shortened transport distances. The study presented in this paper concerns the material, mechanical, durability and short-term structural behaviour of concrete specimens and structures made with recycled aggregates sourced from high-quality concrete elements. This paper intends to provide a holistic view of the study, from the procurement and crushing process that generated the aggregates to the conclusions of the different experiments performed. The results of this experimental campaign are benchmarked with other investigations and the importance of the quality of the RA is evaluated. This paper concerns the first full-scale experiments made on recycled aggregates concrete structures. Also, some of the tests performed were the first of their type made on recycled aggregates concrete.

Structural, material, mechanical and durability properties and behaviour of recycled aggregates concrete

Modeling and identification of a solenoid valve for PWM control applications

Multimodal medical image fusion is effectuated to minimize the redundancy while augmenting the necessary information from the input images acquired using different medical imaging sensors. The sole aim is to yield a single fused image, which could be more informative for an efficient clinical analysis. This paper presents a two-stage multimodal fusion framework using the cascaded combination of stationary wavelet transform (SWT) and non sub-sampled Contourlet transform (NSCT) domains for images acquired using two distinct medical imaging sensor modalities (i.e., magnetic resonance imaging and computed tomography scan). The major advantage of using a cascaded combination of SWT and NSCT is to improve upon the shift variance, directionality, and phase information in the finally fused image. The first stage employs a principal component analysis algorithm in SWT domain to minimize the redundancy. Maximum fusion rule is then applied in NSCT domain at second stage to enhance the contrast of the diagnostic features. A quantitative analysis of fused images is carried out using dedicated fusion metrics. The fusion responses of the proposed approach are also compared with other state-of-the-art fusion approaches; depicting the superiority of the obtained fusion results.

Multimodal Medical Image Sensor Fusion Framework Using Cascade of Wavelet and Contourlet Transform Domains

Environmental effects on natural frequencies of the San Pietro bell tower in Perugia, Italy, and their removal for structural performance assessment

The results of an ambient-vibration based investigation conducted on a historical tower in Italy, to update the 3-D finite element model of the building are presented in this work. The main difficulties are related to the extreme in-homogeneity of the building and the presence of an elevator vain that occupies the posterior part of the tower, forcing to locate the accelerometers only on one facade of the building. The assessment procedure include full-scale ambient vibration testing, modal identification from ambient vibration responses using three different identification methods, finite element modeling and dynamic-based identification of the uncertain structural parameters of the model. A very good match between theoretical and experimental modal parameters was reached and the model updating has been performed to identify some structural parameters.

Ambient vibration testing, dynamic identification and model updating of a historic tower

Experimenting and modelling the dynamics of pneumatic actuators controlled by the pulse width modulation (PWM) technique

This paper presents a novel, wearable navigation system for visually impaired and blind pedestrians that combines a global positioning system (GPS) for user outdoor localization and tactile-foot stimulation for information presentation. Real-time GPS data provided by a smartphone are processed by dedicated navigation software to determine the directions to a destination. Navigational directions are then encoded as vibrations and conveyed to the user via a tactile display that inserts into the shoe. The experimental results showed that users were capable of recognizing with high accuracy the tactile feedback provided to their feet. The preliminary tests conducted in outdoor locations involved two blind users who were guided along 380–420 m predetermined pathways, while sharing the space with other pedestrians and facing typical urban obstacles. The subjects successfully reached the target destinations. The results suggest that the proposed system enhances independent, safe navigation of blind pedestrians and show the potential of tactile-foot stimulation in assistive devices.

An Outdoor Navigation System for Blind Pedestrians Using GPS and Tactile-Foot Feedback

The huge spreading of Internet of things (IoT)-oriented modern technologies is revolutionizing all fields of human activities, leading several benefits and allowing to strongly optimize classic productive processes The agriculture field is also affected by these technological advances, resulting in better water and fertilizers’ usage and so huge improvements of both quality and yield of the crops In this manuscript, the development of an IoT-based smart traceability and farm management system is described, which calibrates the irrigations and fertigation operations as a function of crop typology, growth phase, soil and environment parameters and weather information; a suitable software architecture was developed to support the system decision-making process, also based on data collected on-field by a properly designed solar-powered wireless sensor network (WSN) The WSN nodes were realized by using the ESP8266 NodeMCU module exploiting its microcontroller functionalities and Wi-Fi connectivity Thanks to a properly sized solar power supply system and an optimized scheduling scheme, a long node autonomy was guaranteed, as experimentally verified by its power consumption measures, thus reducing WSN maintenance In addition, a literature analysis on the most used wireless technologies for agri-food products’ traceability is reported, together with the design and testing of a Bluetooth low energy (BLE) low-cost sensor tag to be applied into the containers of agri-food products, just collected from the fields or already processed, to monitor the main parameters indicative of any failure or spoiling over time along the supply chain A mobile application was developed for monitoring the tracking information and storing conditions of the agri-food products Test results in real-operative scenarios demonstrate the proper operation of the BLE smart tag prototype and tracking system

Development of Sensors-Based Agri-Food Traceability System Remotely Managed by a Software Platform for Optimized Farm Management

Purpose – This research aims to address the issue of safe navigation for autonomous vehicles in highly challenging outdoor environments. Indeed, robust navigation of autonomous mobile robots over long distances requires advanced perception means for terrain traversability assessment. Design/methodology/approach – The use of visual systems may represent an efficient solution. This paper discusses recent findings in terrain traversability analysis from RGB-D images. In this context, the concept of point as described only by its Cartesian coordinates is reinterpreted in terms of local description. As a result, a novel descriptor for inferring the traversability of a terrain through its 3D representation, referred to as the unevenness point descriptor (UPD), is conceived. This descriptor features robustness and simplicity. Findings – The UPD-based algorithm shows robust terrain perception capabilities in both indoor and outdoor environment. The algorithm is able to detect obstacles and terrain irregularities....

https://www.vagostudio.com/giulio/wp-content/uploads/2014/04/SR_2014.pdf

Nicola Ivan Giannoccaro

Papers

Ambient vibration testing, dynamic identification and model updating of a historic tower

Experimenting and modelling the dynamics of pneumatic actuators controlled by the pulse width modulation (PWM) technique

An Outdoor Navigation System for Blind Pedestrians Using GPS and Tactile-Foot Feedback

Development of Sensors-Based Agri-Food Traceability System Remotely Managed by a Software Platform for Optimized Farm Management

3D traversability awareness for rough terrain mobile robots