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Heat exchange between environment and workpiece during a manufacturing process can lead to temperature gradients and strains within the workpiece and can result in residual stresses. The correlations between the generated thermal loads and the resulting modifications are called Process Signature. The presented investigations were performed to validate residual stress calculations for laser hardening. Furthermore, the potential of speckle photography for in-situ measurement of displacements as an additional result for simulation validation were evaluated. [ABSTRACT FROM AUTHOR]

According to standards, the lighting system is one of the key elements to provide safety on city roads, defined by quality parameters. LED technology and movement detection sensor interaction bring about new regulation techniques, creating an energy-efficient smart LED lighting system concept. This paper reveals extensive comparative data analysis of Dialux simulation results before the project implementation phase and in-situ quality parameter measurements for various street profiles and LED luminary power types. After the project implementation phase, more than 1000 measurement points are reached. Further, energy efficiency increase issues in smart lighting systems are described in terms of LED luminary dimming profile analysis and future dynamic control application modes. The first findings clearly show that in most cases light output in simulation results is lower than in real situations; therefore, LED luminary power can be decreased, allowing for higher energy savings in first luminary maintenance years, keeping the same defined ME class or safety level. Let us suppose that the traffic intensity data are obtained from smart system sensors. In that case, the ME class can be dynamically selected during different night times, thus increasing safety and providing extra energy savings using the same system elements, as well as leading to better ROI values. [ABSTRACT FROM AUTHOR]

The development of digital building twins in the Architecture, Engineering, Construction and Operation (AECO) sector requires the adoption of adequate monitoring strategies for building components. This article presents a proposal and validation of a digital twin-enabled hygrothermal monitoring procedure applied to lightweight concrete using an IoT Arduino-based prototype. This study conducted tests to measure moisture in three types of lightweight concrete for over a year. Temperature and relative humidity sensors were embedded in the lightweight concrete samples. The recorded data were compared to four in-situ surface moisture meters and gravimetric analysis. Although surface moisture meters have different reference scales, the qualitative assessment is similar. The embedded sensors preserved their performance levels during the entire testing period, even those exposed to relative humidity levels near 100 %. The continuous monitoring of temperature and relative humidity in non-structural construction elements, using low-cost sensors embedded during construction, is proven to be viable. [Display omitted] • Assessment of the drying process of lightweight concrete with three different densities. • Moisture monitoring in digital building twins can prevent building pathologies. • Over the 425-day testing period, the low-cost sensors exhibited no degradation. • Surface moisture meters with a capacity of sensing deeper provides better accuracy. • At 20 °C/30 %, samples with 800 kg/m³ takes over 4 times longer to dry than with 525 kg/m³. [ABSTRACT FROM AUTHOR]

The methane hazard is one of the most dangerous phenomena in hard coal mining. In a certain range of concentrations, methane is flammable and explosive. Therefore, in order to maintain the continuity of the production process and the safety of work for the crew, various measures are taken to prevent these concentration levels from being exceeded. A significant role in this process is played by the forecasting of methane concentrations in mine headings. This very problem has been the focus of the present article. Based on discrete measurements of methane concentration in mine headings and ventilation parameters, the distribution of methane concentration levels in these headings was forecasted. This process was performed on the basis of model-based tests using the Computational Fluid Dynamics (CFD). The methodology adopted was used to develop a structural model of the region under analysis, for which boundary conditions were adopted on the basis of the measurements results in real-world conditions. The analyses conducted helped to specify the distributions of methane concentrations in the region at hand and determine the anticipated future values of these concentrations. The results obtained from model-based tests were compared with the results of the measurements in realworld conditions. The methodology using the CFD and the results of the tests offer extensive possibilities of their application for effective diagnosis and forecasting of the methane hazard in mine headings. [ABSTRACT FROM AUTHOR]

Abstract Reduction of the CO 2 emissions in the atmosphere is one of the goals set forth by the European Union, hence various directives have been adopted, such as the European directive 2012/27/EU on energy efficiency, i.e. ensuring from 2019 the construction of the near-zero energy buildings (nZEB). The construction segment plays a very important part in solving the current global problem of the greenhouse gas emissions and related processes of global warming, because in certain countries (i.e. in Latvia) it represents more than a half of the total energy consumption. Hence the necessity to elaborate means on how to boost the energy efficiency of the buildings meanwhile not rising pressure on the CO 2 emissions released by the industry of construction materials and their transportation. Hemp-lime concrete is one of the materials that can be used to increase the energy efficiency, it is a new thermal insulation material produced from the local raw materials, and in its production cycle more CO 2 is absorbed than produced. This research aims at determining the thermal insulation properties of this material in field conditions and comparing them with results from the laboratory measurements to analyse performance of such materials in the temperate continental climate zone of Europe. Measurements have been recorded on a specifically designed portable measurement equipment with sensors for the temperature, humidity and heat flux. The obtained results present a positive correspondence with the laboratory measurements, thus proving high potential for use of these materials to increase the energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

The indoor hygrothermal conditions can affect human related quality of life. This subject is of special relevance in the context of social housing, which are frequently overcrowded and lack appropriate heating, ventilation and insulation. In this research, two social housing neighbourhoods were studied in depth: one rehabilitated and another non-rehabilitated. In-situ measurement campaigns, one in winter and one in summer, and structured questionnaires conducted with the inhabitants were used to characterize the performance of the dwellings. The measurements evidenced that the winter indoor environment in the rehabilitated neighbourhood was warmer and less damp. Moreover, the users of the rehabilitated dwellings demonstrated an increased satisfaction with their housing conditions. On the other hand, the administration of the Short Form Health survey (SF36) instrument lead to results where no significant differences were found between the population living in rehabilitated and non-rehabilitated neighbourhoods. A cluster analysis allowed for the identification of two sets of dwellings with significantly different hygrothermal indoor environments that again demonstrated no significant differences regarding the SF36 dimensions. The questions not linked to SF36 had, however, a more successful result highlighting increased satisfaction of the users in the rehabilitated neighbourhood. [ABSTRACT FROM AUTHOR]

This study develops an approach to examine parameters that are used for the estimation of seismic loads for historic buildings. A literature review is presented, and data from the literature and laboratory tests are used to assess the provisions that should be satisfied after the restoration of such buildings. In the analysis, frames with nonlinear properties that model stone masonry plain frames are used to estimate the equivalent seismic acceleration that these frames can resist. To investigate the response of masonry monuments to strong earthquakes, the observed response of many temples is considered during seven earthquakes in Greece, and the response spectra are defined for equivalent damping levels of 5%, 10%, and 20%. The aforementioned approaches are used to examine the possibility of further reducing the considered seismic loads for the evaluation of these structures. Alternative methods for the justified reduction of the seismic force by increasing the behavior factor are proposed. Finally a case study is presented on the initial contsruction stage of a byzantine basilica. In this case, the observed failure of the main roof of the temple and the limitation of damages to the rest of the structure thanks to the use of the findings of the present research is justified. [ABSTRACT FROM AUTHOR]

The growing effort of reducing energy needs in the building sector calls for an accurate characterization of the performances of external walls, which are the main cause of thermal exchanges and consequently are fundamental to realize accurate simulation models to evaluate and control thermal loads. The dynamic characterization of a multilayer wall can be performed by defining its stratigraphy and the thermo-physical parameters of each layer. When existing buildings are investigated, technical specifications may be unknown or difficult to obtain due to documents lost over time; furthermore, aging may have altered the building materials characteristics. In these cases, in-situ measurements become essential but there is the need to analyze the behavior of walls considering their dynamic characteristics, not obtainable by employing non-destructive tests, such as the heat-flow meter method. The paper aims to verify if an equivalent homogeneous wall can be associated to a multilayer wall in the sense of producing the same behavior if exposed to the same outdoor environmental conditions. Findings in literature demonstrate that, generally, this is not exactly achievable. However, the possibility of an approximate equivalence is investigated in this work by means of finite-element simulations and experimental measurements. The results obtained in actual case studies show that this equivalence can be made, obtaining preliminary satisfying results. The proposed methodology can be employed in existing and historical buildings to achieve useful equivalent data directly applicable for the energy retrofit phase and for achieving a better coupling between the building and the heating/cooling system, reducing environmental impacts. [ABSTRACT FROM AUTHOR]

A dynamic method, comprising a two lumped-thermal-mass model and Markov Chain Monte Carlo sampler, was used to analyze in-situ-monitored data and estimate the thermophysical properties of two walls of different construction. This method, unlike maximum a posteriori approaches, estimates the parameters' probability distributions, providing insight into the wall's thermal structure. Total R-values were well defined for both walls, whilst constituent estimated R-values for a solid wall having layers of materials with similar thermal properties were anticorrelated (thermal mass locations weakly constrained), but were not correlated for an insulated cavity wall with thermally distinct layers (thermal mass locations strongly thermally constrained). [ABSTRACT FROM AUTHOR]

In the process of building performance assessment, it is often necessary to resort to assumptions to fill in missing information. We address the issue of scarcity of information about the building properties by employing new sensing technology. The aim of this paper is to introduce an open-source, modular and low-cost wireless sensor network of building performance assessment, which is independent of an onsite landline internet connection. Due to its modularity, the WSN can be complemented with new sensors without altering the system. We present the design process, the deployment and monitoring results of an easily-deployable wireless sensor network (WSN) for in-situ performance assessment of occupied buildings. A case study of the deployment of the WSN in a single family home in Switzerland is presented. We demonstrate the quick installation of the WSN and live measurements over multiple months. We derive the thermal properties of the envelope (U-values) from the measured data, and compare them to the values used in the code-based assessment of the building. [ABSTRACT FROM AUTHOR]

Overheating in the residential buildings has been identified as a major challenge in terms of public health especially in an urban context. Increased duration and frequency of heatwaves associated with climate change will increase the severity of overheating. However to date overheating has not been adequately addressed by the building regulations. In a case study retrofit high rise apartment block in Leeds, UK major overheating has been identified through and in-depth building performance evaluation (BPE) study. The study was extended with transient dynamic modelling of top floor apartments to explore the effectiveness of 18 fabric and practices scenarios based on actual BPE findings. The results show 10-30% difference in overheating severity was caused by a performance gap in relation to the building fabric. What's more they indicate that in the given climatic conditions of summer 2013 overheating might have been avoided if shading was introduced and mechanical extract ventilation used as designed. This points towards the need of focusing more attention on overheating prevention at design and handover stages. [ABSTRACT FROM AUTHOR]

It is often necessary to check the intrinsic acoustic characteristics of installed noise barriers, like sound reflection and airborne sound insulation, to verify their compliance to design specifications or their quality after some years of life. These characteristics may be measured in-situ following CEN/TS 1793-5. These guidelines have been substantially improved in the frame of the European project QUIESST (2009–2012), which is now under consideration by the relevant CEN working groups to produce new European standards. The new method for measuring sound reflection specifies the usage of an electroacoustic sound source and a microphone grid, in order to obtain a set of impulse responses; these are processed by means of improved algorithms to compute the required results. The impulse responses are acquired using MLS (Maximum Length Sequence) or ESS (Exponential Swept-Sine) as test signals. While the acoustical characteristics of a noise barrier obtained using the two signals are generally equivalent, in critical conditions – e.g. excessive background noise or local meteorological variability – some discrepancies may occur. Moreover, different type of background noise (broadband or impulsive) give different effects on the final result, using MLS or ESS test signals. This paper presents a series of experiments designed to put in evidence the differences between Reflection Index measurements performed in the mentioned critical conditions, according to the QUIESST guidelines, done using MLS or ESS signals. The relative advantages and drawbacks are analysed and discussed in detail. Conclusions are drawn on the selection of the best test signal for each situation. [ABSTRACT FROM AUTHOR]

The thermal resistances of a building's components are main parameters in assessing the overall thermal performance of the building envelope. In order to assess the actual, as-built thermal performance of building components, a reliable thermal characterization of building elements from on-site measurements is required. In this paper, the thermal resistance of a cavity wall is estimated by means of maximum likelihood estimation (MLE) from on-site meas rements. To evaluate the performance of MLE the method is applied on various data sets of the outdoor test wall. Based on the results for all data sets, the potentials of the dynamic estimation technique are considered. Special attention is paid to the accuracy of the estimation results in function of the measurement length and the measurement period throughout theyear. [ABSTRACT FROM AUTHOR]

This contribution reports on ongoing efforts exploring the potential of aerogel-based plasters on historical façades. As a case study, aerogel-based plaster was applied without reinforcement meshes to a small area in the historical main building of the Vienna University of Technology. The objective is to examine the long-term behavior of the plastered surfaces. For this, a monitoring infrastructure has been implemented, which enables the in-situ measurement of temperature, humidity, and heat flux within different layers of the construction using a wireless sensor system. These measurements are intended to offer a before- after comparison of the thermal behavior of the treated components. [ABSTRACT FROM AUTHOR]

Optical signal transmission is an important component of numerous underwater applications, including visibility and electro-optical (EO) communication. In addition to the well-studied effect of particle backscatter, underwater optical signal transmission can be limited by changes in the index of refraction (IOR) due to small-scale variations in temperature and salinity, sometimes called “optical turbulence”. These variations in IOR, which are associated with oceanic turbulence, can lead to the blurring of an underwater optical target, particularly at high spatial frequencies, thus reducing target detail. The 2011 Bahamas Optical Turbulence Experiment (BOTEX) was conducted to investigate this impact of turbulence on underwater optical signal transmission. Investigating naturally occurring “optical turbulence” requires a platform held at depth, capable of concurrent measurements of optical impairment by turbulence, which requires a significant optical path length, as well as associated physical and optical background conditions of the ambient environment. Our novel platform consisted of a high-speed camera and optical target mounted on a 5 m -long frame, along with several Nortek Vector Acoustic Doppler Velocimeter (ADV) and PME Conductivity–Temperature (CT) probes, to estimate turbulent kinetic energy and temperature variance dissipation rates experienced by the frame. Data on the background turbulence was collected with a Rockland Oceanographic Vertical Microstructure Profiler, to aid in analysis and guide error estimates of the ADV/CT measurements. This study was the first effort attempting to collect turbulence measurements on a frame designed for the investigation of the effect of density microstructure variations on optical signal transmission in the open ocean. Our results highlight the numerous challenges associated with studying this phenomenon in the dynamic oceanic environment. Here, we present the interpretation of the high-resolution velocity and temperature measurements collected on the frame and discuss the associated difficulties. Despite the numerous challenges, the investigation of the effect of microstructure on underwater optics is needed for efforts aimed at mitigating the impact of “optical turbulence” on underwater EO signal transmission and may help advance optical methods to quantify oceanic microstructure. [ABSTRACT FROM AUTHOR]

Abstract: We present a method for measuring one-dimensional surface wave spectra using a ship-mounted ultrasonic altimeter in combination with a motion correction device. The instruments are mounted at the bow of the ship and provide high-resolution, local, wave information. We present results from three recent field studies. The results are compared with data from a conventional waverider buoy and, when in-situ observations are not available, with wave model analyses and satellite altimetry. We find good agreement with regard to integrated parameters such as significant wave height and mean period. Comparison with a waverider demonstrates fair agreement with regard to spectral shape, but the representation of the low frequency part depends on the quality of the motion correction data. [Copyright &y& Elsevier]

Abstract: A mode I fracture criterion applicable for cracks oriented in the transverse plane in softwood is studied at the mesoscopic scale, i.e. the annual ring scale. Numerical investigation combined with digital image correlation help to obtain wood fracture parameters into the annual ring. These parameters give additional knowledge and understanding for wood fracture according to local specificities such as crack tip position into an annual ring and notch orientation related to wood natural orientation and solicitation orientation. [Copyright &y& Elsevier]

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Abstract: A mode I fracture criterion applicable for cracks oriented in the transverse plane in softwood is studied at the mesoscopic scale, i.e. the annual ring scale. Numerical investigation combined with digital image correlation help to obtain wood fracture parameters into the annual ring. These parameters give additional knowledge and understanding for wood fracture according to local specificities such as crack tip position into an annual ring and notch orientation related to wood natural orientation and solicitation orientation. [Copyright &y& Elsevier]

Measurements are reported of piston secondary motion, piston ring motion, piston ring oil-film thicknesses, piston ring pack oil chemistry, piston friction and piston temperatures, using a variety of experimental techniques on running engines. These in-situ measurements have highlighted a number of interesting effects, of importance to both the piston designer and the lubricant formulator. [ABSTRACT FROM AUTHOR]