Early-Age Thermal-Shrinkage Cracking in Deep Foundations

With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.

Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

The Influence of Pantograph Carbon–Metal Composite Slider Thermal Properties on the Railroad Wire Temperature

This article presents the methodology, description, and results of experimental studies aimed at determining the impact of the copper concentration in a carbon–metal composite contact strip on the maximum temperature of the copper contact wire during a contact event when used for operation in the railway industry in Europe. Based on these tests, we determined the minimum percentage of copper that is required for the composite to meet the normative requirements for current loads. In addition to experimental research, a 3D FEM numerical model was also developed in which the contact strip and contact wire geometry were mapped, along with imposed loads resulting from the test for current loads mentioned above. Fifteen simulation variants were carried out for the established model, where the value of the thermal conductivity coefficient and the specific heat coefficient were varied. On this basis, we analyzed the sensitivity of thermal coefficients to the contact wire temperature and determined the minimum conductivity coefficient value, which allowed the maximum copper contact wire temperature of 120 °C to be obtained during the verification tests.

Hydrocarbon Fractions from Thermolysis of Waste Plastics as Components of Engine Fuels

Plastics are one of the basic construction materials with a wide range of various applications. One of their disadvantages is the problem of managing the waste they generate. Chemical recycling offers the possibility of liquefying polymeric waste and using it as fuel components. Existing technologies giving good quality products are expensive. The HT technology developed and described by the authors is cheaper and enables a high quality product to be obtained. The authors have shown that the quality of the received fuel components is influenced not only by the polymer waste processing technology, but also by the feedstock composition. The presented thermolysis technology not only enables more advanced recycling, but also gives the possibility of partial improvement of the product quality. A product with the best physico-chemical properties was obtained from a blend of PE:PP:PS used in the ratio 60:30:10. It was proved that diesel and petrol blends composed of a 5% v/v share of petrol and diesel fractions, obtained from thermolysis of plastics, meet the normative requirements of fuel quality standards.

On the Low Frequency Impact Noise Measurement in Residential Buildings

We commonly encounter cases that, despite the fact that buildings meet normative requirements, people are disturbed by unwanted noise generated by walking and other sources of impact noise. It is not unusual that in practice the designer often moves on the edge of the required criteria in order to reduce the cost of constructions and its parts. In this article, we selected 4 blindly chosen cases of flats where complaints from residents about high levels of impact noise were recorded although the construction meets the requirements set out in the standard. Based on the obtained documentation of in-situ performed measurements by different consulting companies, BEM and FEM models were created, and the distribution of acoustic pressure in an enclosed space and compared different methods of spatial averaging of the resulting acoustic pressure were simulated. The aim of this analysis is to point some of the reasons for possible user complaints about the impact noise despite normative requirements. The usual problems are benevolent national requirements and the issue of measuring noise in the low frequency range and underestimating its significance. The article also discusses the currently set requirements for the evaluation of floor structures in selected countries.

Legal and Normative Requirements Related to Medical Devices for Individual Supply in Clinical Practice

This article has the form of a communication presenting recent legal changes in relation to medical devices. Until 26 May 2021, three medical directives were in force, namely Directive 98/79 / EC, Council Directive 93/42/ EEC and Council Directive 90/385 / EEC. They have been replaced by two regulations: Regulation (EU) 2017/745 on medical devices and Regulation (EU) 2017/746 on in vitro diagnostic medical devices. The article presents the reasons for introducing the changes and the new obligations that these changes bring for manufacturers of medical devices, in particular, products manufactured individually on a special order as necessary for the implementation of personalized therapies in clinical practice. There are also forecasts for the industry and end users of medical devices manufactured to order and used individually at medical centers.

AI Systems and Respect for Human Autonomy

This study concerns the sociotechnical bases of human autonomy. Drawing on recent literature on AI ethics, philosophical literature on dimensions of autonomy, and on independent philosophical scrutiny, we first propose a multi-dimensional model of human autonomy and then discuss how AI systems can support or hinder human autonomy. What emerges is a philosophically motivated picture of autonomy and of the normative requirements personal autonomy poses in the context of algorithmic systems. Ranging from consent to data collection and processing, to computational tasks and interface design, to institutional and societal considerations, various aspects related to sociotechnical systems must be accounted for in order to get the full picture of potential effects of AI systems on human autonomy. It is clear how human agents can, for example, via coercion or manipulation, hinder each other’s autonomy, or how they can respect each other’s autonomy. AI systems can promote or hinder human autonomy, but can they literally respect or disrespect a person’s autonomy? We argue for a philosophical view according to which AI systems—while not moral agents or bearers of duties, and unable to literally respect or disrespect—are governed by so-called “ought-to-be norms.” This explains the normativity at stake with AI systems. The responsible people (designers, users, etc.) have duties and ought-to-do norms, which correspond to these ought-to-be norms.

Investigating the Condition Monitoring Potential of Oil Conductivity for Wear Identification in Electro Hydrostatic Actuators

To meet future goals of more electric airplanes conventional hydraulic airplane control systems, consisting of redundant centralized pumps within the airplane’s fuselage, need to be substituted for compact electro-hydraulic actuators (EHA). The capsulated architecture of EHAs results in higher safety due to separate hydraulic circuits, simple practicability of redundancy, decreased maintenance because of simplified error location detection as well as an overall reduction in weight and complexity of the airplane control system. Currently, EHAs are only used as backup devices as the reliability does not achieve normative requirements for a frontline application. Thus, recent studies aim to increase the reliability. The axial piston pump of current EHA is the source of most failures. High dynamic requirements and challenging operation points and environments result in wear of contact pairs such as swash plate/piston shoes, pistons/cylinder block and cylinder block/valve plate. In the scope of the project MODULAR at ifas one goal is to increase the robustness of the contact surfaces. A second goal addresses the topic of developing a condition monitoring approach to constantly track the pumps’ health status. Next to signals such as pressures and temperatures, acceleration and oil status signals describing the actual particle contamination are needed. In this contribution different methods of oil status detection are explained and the method of electric conductivity analysis for condition monitoring is further investigated. Filtered HLP46 is used and impurities in form of metallic powders are added. Furthermore, degraded oil of a disc-on-disc Tribometer test bench is measured and compared.

Laboratory investigations on the quality of leak tests and visual inspections of wastewater connection pipes carried out by specialist contractors

In addition to stability and operational safety, leak tightness is the permanent functional objective of wastewater pipes. Tests to determine the tightness of wastewater pipes can in some cases produce results that are worthy of discussion. Therefore, laboratory tests were carried out by 29 specialist contractors to obtain results on the quality of leak tests and visual inspections of connection pipes. The results showed that different test errors can be observed for leak test methods (air overpressure, air underpressure and water pressure). However, only in the case of the water pressure tests did the observed test errors occasionally lead to incorrect test results, i.e. the ‘leaking pipe’ was tested as ‘test passed (tight)’. The investigations into the accuracy (trueness and precision) of the test methods showed that all test methods examined were sufficiently accurate to determine the tightness of the connection pipes. In general, correct test results were achieved if the expert testers did not make any serious test errors and the test equipment used functioned properly. In contrast, the investigations on the quality of visual inspection showed that the procedure is not sufficiently reliable to fulfil all normative requirements regarding damage detection and naming as well as damage classification.

Medina’s Habitation as a Sustainable Investment Factors: Thermal Experience

The study examined significant summer heat effects on a traditional habitation cluster within a compact fabric of the Medina of Constantine, based on building materials and spatial functional architecture. As climate relates to energy effects, the study raises the importance of possible heat gains in the approach of thermal comfort through building materials without using other energy sources. The study employed both empirical and comparative methods to undertake the research work. The empirical method consisted of taking thermal and metric measurements of the habitation cluster and comparing them with current normative requirements in sustainable architecture. The comparative method consisted of comparing results of performance assessment of studied building materials with results of similar materials. The current study adds to researchers' claims about the importance of the Medina's habitation in the face of climatic aggression at times with its architecture and building materials. Medina’s habitat did not have the technological means to preserve some physical comfort and reduce greenhouse gas emissions, yet its architecture used soft means to accomplish the physical comfort. Additionally, the site's well-chosen materials, which are formed by the natural typology, match well with the site’s climate and provide better resistance to material overflow, not to mention their availability and inexpensive cost.