The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Climate change 2014 - Mitigation of climate change

Ultrasonic testing of materials: Josef and Herbert Krautkramer Springer-Verlag Publishing Company, Berlin, Heidelberg, New York (1975) 669 pp, $63.00

Nondestructive evaluation (NDE) research on composite materials has been ongoing for several decades, during which time their use has expanded significantly in the aerospace, marine, petrochemical, energy, construction and transport sectors. Initially, many composites were employed as fairings or reinforcements, but they are being increasingly used in primary and secondary load-bearing structures, where a mechanical failure has significantly greater safety implications. This increased scope has resulted in composite structures of significant thickness and complexity. Despite this, there has not been a corresponding increase in research pertinent to the detection and characterisation of defects in thick structures, apart from a brief period of interest by the NDE community in the early 1990s. This review critically assesses advances reported in the NDE of thick-section composites (structures of thickness above 15 mm are considered for the purposes of this review), and identifies future research opportunities to overcome the limitations of existing technologies.

Nondestructive evaluation of thick-section composites and sandwich structures: A review

Advances, limitations and prospects of nondestructive testing and evaluation of thick composites and sandwich structures: A state-of-the-art review

Polymer composite materials are being increasingly used in primary load-bearing structures in several advanced industrial fields such as aerospace vessels, railway wagons and mega-scaled wind turbines where detection of subcritical damage initiation can significantly reduce safety issues and maintenance costs. It is therefore crucial to inspect these composite structures in order to assess their structural health and to ensure their integrity. Non-destructive testing techniques (NDT) are used for this purpose, making it possible to monitor mechanical damage of composite materials under in situ or ex situ service conditions. This paper reviews the capabilities of the most common NDT techniques used to inspect the integrity of composite materials. Each technique has a detection potential and cannot allow a full diagnosis of the mechanical damage state of the material. Thus, depending on the occurring damage mechanism and the conditions of use, one technique will be preferred over another, or several techniques should be combined to improve the diagnosis of the damage state of the structures.

A review of non-destructive techniques used for mechanical damage assessment in polymer composites

FEM based design of experiment for train wheelset diagnostics by laser ultrasonics.

The present paper describes the quantitative validation of a finite element (FE) model of the ultrasound beam generated by an air coupled non-contact ultrasound transducer. The model boundary conditions are given by vibration velocities measured by laser vibrometry on the probe membrane. The proposed validation method is based on the comparison between the simulated 3D pressure field and the pressure data measured with interferometric laser tomography technique. The model details and the experimental techniques are described in paper. The analysis of results shows the effectiveness of the proposed approach and the possibility to quantitatively assess and predict the generated acoustic pressure field, with maximum discrepancies in the order of 20% due to uncertainty effects. This step is important for determining in complex problems the real applicability of air-coupled probes and for the simulation of the whole inspection procedure, also when the component is designed, so as to virtually verify its inspectability.

Quantitative validation of an air-coupled ultrasonic probe model by Interferometric laser tomography

Automated measurement system for detecting carbonation depth: Image-processing based technique applied to concrete sprayed with phenolphthalein

The apparent density (or, as often reported in the technical literature, the bulk density) of green ceramic tiles is a fundamental parameter for the quality of final products. In fact, the apparent density determines the entity of the dimensional shrinkage of the ceramic body during firing and is proportional to the mechanical resistance. In industrial production an irregular shrinkage can be responsible for example for nonplanar tiles or residual strengths. Measuring the apparent density allows to control this parameter to limit the production waste and increase the quality of the final product. The apparent density, in the ceramic industries, can be currently measured off-line [Standard UNI EN 1097 – 3, (1999)], and the most used method is generally the hydrostatic weighting in a mercury bath on a small sample [Pei at al, (1999)]. This technique has a limit on the control sample and a continuous mercury use is dangerous for the human health. This, together with ISO 14000 Standard application, poses severe limitations to the use of mercury in Europe, in the United States and other countries. So new methods have been developed to measure the bulk density of ceramic tiles. Some are based on the gas laws utilizing air pressure to determine test specimen volume in a measuring chamber [Dietrich, (1999)], whilst more recent ones are based on X-ray absorption [Amoros at al, (2010)]. The first is a destructive and discrete method, so it is not suitable for on-line application. The second is accurate and non-destructive, but can be expensive and X-ray devices still have some acceptance problems in industry. In this chapter an innovative method for non-contact measurement of the apparent density of green ceramics is presented, which is also suitable to be used during production. This method, previously developed by the authors, is based on ultrasonic wave propagation within the material. The waves are generated and received by dedicated air-coupled probes. The time of flight is measured in transmission mode on the tile together with the thickness. The thickness can be derived by the ultrasonic signals or, if higher accuracy is required on complex shapes, by a laser triangulation sensor. The velocity of the ultrasound wave can be calculated by these measurements and it is proportional to the apparent density. The conversion factor between velocity and apparent density is evaluated by a calibration procedure with a reference method of known uncertainty (e.g. mercury bath). The chapter not only summarizes the research steps performed in this field in the last 10 years for measurements both at the laboratory and industrial level, but also presents a new challenging application to pieces with complex shapes.

https://cdn.intechopen.com/pdfs/17534/InTech-Non_contact_measurements_of_the_apparent_density_of_green_ceramics_with_complex_shape.pdf

Non-Contact Measurements of the Apparent Density of Green Ceramics with Complex Shape

Continuous measurement of building's thermal performances is relevant to guarantee the first function of a building: providing a comfortable and healthy living environment with minimum energy consumption. This work aims at exploring the Comfort Eye, an IoT multi-sensor device, applied for continuous and real-time building's thermal monitoring. In this context, the Comfort Eye is adopted to identify the main sources of discomfort or inefficiencies of building's envelope, e.g., points of condensation risk, and to provide an alternative experimental method for measuring the surface temperature of building elements, through which it is possible to estimate the heat transfer coefficient or U-value. To validate the method for measuring the thermal insulation performance of building elements, a verification experiment using a real building was conducted. The results confirmed that the required measuring accuracy can be assured. Moreover, the innovative methodology described in this paper can be used for relatively fast and inexpensive U-value estimation without the use of additional measurement equipment (e.g., heat flux sensors).

Giuseppe Pandarese

Papers

FEM based design of experiment for train wheelset diagnostics by laser ultrasonics.

Quantitative validation of an air-coupled ultrasonic probe model by Interferometric laser tomography

Automated measurement system for detecting carbonation depth: Image-processing based technique applied to concrete sprayed with phenolphthalein

Non-Contact Measurements of the Apparent Density of Green Ceramics with Complex Shape

IoT infrared sensor for continuous monitoring of building envelope thermal performances