Towards Interpretable Machine Learning for Automated Damage Detection Based on Ultrasonic Guided Waves

Data-driven analysis for damage assessment has a large potential in structural health monitoring (SHM) systems, where sensors are permanently attached to the structure, enabling continuous and frequent measurements. In this contribution, we propose a machine learning (ML) approach for automated damage detection, based on an ML toolbox for industrial condition monitoring. The toolbox combines multiple complementary algorithms for feature extraction and selection and automatically chooses the best combination of methods for the dataset at hand. Here, this toolbox is applied to a guided wave-based SHM dataset for varying temperatures and damage locations, which is freely available on the Open Guided Waves platform. A classification rate of 96.2% is achieved, demonstrating reliable and automated damage detection. Moreover, the ability of the ML model to identify a damaged structure at untrained damage locations and temperatures is demonstrated.

Lengthening of summer season over the Northern Hemisphere under 1.5°C and 2.0°C global warming

Summer season has lengthened substantially across Northern Hemisphere (NH) land over the past decades, which has been attributed to anthropogenic greenhouse gas increases. This study examines additional future changes in summer season onset and withdrawal under 1.5℃ and 2.0℃ global warming conditions using multiple atmospheric global climate model (AGCM) large-ensemble simulations from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project. Five AGCMs provide more than 100 runs of 10-year length for three experiments: All-Hist (current decade: 2006-2015), Plus15, and Plus20 (1.5℃ and 2.0℃ above pre-industrial condition, respectively). Results show that with 1.5℃ and 2.0℃ warmer conditions summer season will become longer by a few days to weeks over entire NH lands, with slightly larger contributions by delay in withdrawal due to stronger warming in late summer. Stronger changes are observed more in middle latitudes than high latitudes and largest expansion (up to three weeks) is found over East Asia and the Mediterranean. Associated changes in summer-like day frequency is further analyzed focusing on the extended summer edges. The hot days occur more frequently in lower latitudes including East Asia, USA and Mediterranean, in accord with largest summer season lengthening. Further, difference between Plus15 and Plus20 indicates that summer season lengthening and associated increases in hot days can be reduced significantly if warming is limited to 1.5℃. Overall, similar results are obtained from CMIP5 coupled GCM simulations (based on RCP8.5 scenario experiments), suggesting a weak influence of air-sea coupling on summer season timing changes.

Analysis of Transient Boiling Processes during Steel Quenching in Water PAG Solutions to Decrease Distortion

The paper discusses results of testing standard cylindrical probe 12.5 mm diameter in water polymer solutions which was additionally instrumented with a surface thermocouple. It is shown that central thermocouple cannot depict many physical phenomena taking place during quenching in polymer solutions such as shoulder formation, self- regulated thermal process establishing, surface temperature transient from film boiling to nucleate boiling process. Moreover, it is shown that experimental data depicted by central thermocouple cannot be used for solving inverse problem to analyze quenching process in liquid media. Along with analyzing film and nucleate boiling processes during quenching, the paper discusses the possibility of quality quench process control via using sonar system. It is established an equation for evaluating duration of transient nucleate boiling process. As an example, the cooling characteristics of fresh and old polyalkylene glycol (PAG) polymer solutions are analyzed. It is shown that with passing time the critical heat flux density of polymer decreases and inverse solubility effect disappears. That is while the method and apparatus were developed to control in industrial condition the quality of quenched steel parts during hardening in liquid media.

PHOTOCATALYTIC TREATMENT OF WATERS, POLLUTED WITH PHENOLS

The analysis of the environmental and human health threats imposed by phenols was conducted to show the need for further improvement of methods of their destruction. Being toxic in their initial composition and precursor to toxic metabolites in human body, phenols should be controlled in natural water and waste waters. They are listed as priority pollutants in most national regulation around the world and are the initial compounds for the formation of persistent organic pollutants in the environment, polluted with other active radicals. A variety of physical and chemical methods were offered for the destructive or non-destructive removal of phenols and their derivatives from water. The comparative study of possible methods, described in research papers, was conducted in terms of their efficiency and complexity to define benefits and drawbacks. The analysis showed the need for development of low energy consuming method, which needs minimal equipment and can be run under industrial condition for phenol contaminated wastewaters. Among the possible methods which meet the mentioned criteria photocatalytic destruction of phenols was showed to be perspective. A series of experiments was conducted using a range of water solution of phenol and different dosage of catalysts. The catalysts used in experiments were made of 6 modification of titanium oxide and bismuth ferrite. The initial and residual concentration of phenol was controlled by the means of high-performance liquid chromatography. The duration of the exposure and the type of light were other independent variables. The results of the whole sequence of experiments demonstrated higher efficiency of rutile under visible light and one hour of exposure. The tested photocatalytic system is simple and therefore technically and economically feasible.

Introduction to the Special Issue on Artificial Intelligence for Smart Cities and Industries

Smart Cities and Artificial Intelligence offers an intensive evaluation of how the smart city establishments are made at different scales through automated thinking headways, for instance, geospatial information, data examination, data portrayal, clever related things, and quick natural frameworks handiness. Progressing propels in electronic thinking attract us closer to making a persistent reproduced model of human-made and trademark structures, from urban regions to transportation establishments to utility frameworks. This continuous living model empowers us to all the bound to manage and improve these working structures, making them dynamically watchful. Keen Cities and Artificial Intelligence gives a multidisciplinary, joined procedure, using speculative and applied bits of information, for the evaluation of savvy city situations. This special issue shows how the mechanized and physical universes are associated inside this organic framework, and how nonstop data arrangement is changing the possibility of our urban as well as industrial condition. It gives a fresh sweeping perspective on the natural framework designing, advances, and parts that include the masterminding and execution of sharp city and industry establishments. This special issue also shows how the computerized and physical universes are connected inside this biological system, and how continuous information assortment is changing the idea of our urban and industry condition. It gives a crisp all-encompassing viewpoint on the biological system engineering, advances, and parts that involve the arranging and execution of keen city and industry foundations. After following double blind peer review for all the submitted manuscripts across the globe, and after the rigorous review process, revision and based on final recommendations of the reviewers and editorial team, finally 17 manuscripts have been accepted for publication.

Comparative Analysis of Three Different Negative Emission Technologies, BECCS, Absorption and Adsorption of Atmospheric CO2

Negative Emission Technologies (NETs) are generally considered as vital methods for achieving climate goals. To limit the rise in the global average temperature below 2 °C, a large number of countries that participated in the Paris agreement was virtually unanimous about the effective collaboration among members for the reduction of CO2 emissions throughout this century. NETs on the ground that can remove carbon dioxide from the atmosphere, provide an active option to achieve this goal. In this contribution, we compare limiting factors, cost, and capacity of three different NETs, including bioenergy with carbon capture and storage (BECCS), absorption and adsorption. Although there are several advantages for capturing CO2, still some constraints regarding the high operational cost of NETs and industrial condition of these technologies as a method of climate change mitigation is not clear. Thereby no single process can be considered as a comprehensive solution. Indeed, any developed technologies, in turn, have a contribution to the reduction of CO2 concentration. Extensive research needs to be done to assess and decrease NETs costs and limitations.

Capacitance Response of Concave Well Substrate MEMS Double Touch Mode Capacitive Pressure Sensor: Robust Design, Theoretical Modeling, Numerical Simulation and Performance Comparison

Touch Mode Capacitive Pressure Sensor (TMCPS) is very suitable for industrial applications where pressure sensing is necessary because of their linearity, mechanical robust nature and large overload protection from harsh industrial condition. This work proposes an introduction of a notch in the concave substrate for further improvement of the sensitivity of the sensor. Small deflection mode is utilized for the mathematical analysis of the design proposed and MATLAB is utilized for all the software simulations. The sensitivity of the proposed model is very high compared to other models with flat substrate. The analysis and simulation show significant increase in sensitivity in touch mode. The pressure at which the value of the capacitance saturates is also much higher than the designs stated in the literature. The analysis of concave substrate Double Touch Mode Capacitive Pressure Sensor (DTMCPS) will be helpful in designing new sensor for performance increase and to evaluate the behaviour of it.

Current Status and Future Trends in the Operation and Maintenance of Offshore Wind Turbines: A Review

Operation and maintenance constitute a substantial share of the lifecycle expenditures of an offshore renewable energy farm. A noteworthy number of methods and techniques have been developed to provide decision-making support in strategic planning and asset management. Condition monitoring instrumentation is commonly used, especially in offshore wind farms, due to the benefits it provides in terms of fault identification and performance evaluation and improvement. Incorporating technology advancements, a shift towards automation and digitalisation is taking place in the offshore maintenance sector. This paper reviews the existing literature and novel approaches in the operation and maintenance planning and the condition monitoring of offshore renewable energy farms, with an emphasis on the offshore wind sector, discussing their benefits and limitations. The state-of-the-art in industrial condition-based maintenance is reviewed, together with deterioration models and fault diagnosis and prognosis techniques. Future scenarios in robotics, artificial intelligence and data processing are investigated. The application challenges of these strategies and Industry 4.0 concepts in the offshore renewables sector are scrutinised, together with the potential implications of early-stage project integration. The identified technologies are ranked against a series of indicators, providing a reference for a range of industry stakeholders.