Dual mode imaging in the mid infrared band, a joint use of thermography and quasi-thermal reflectography, was recently proposed as a full field diagnostic tool in cultural heritage. Here we discuss ...for the first time, to the best of our knowledge, a detailed application of such non destructive technique to the diagnostics of frescoes, with an emphasis on the location of detachments. We also investigate the use of a thermographic method based on TSR (thermal signal reconstruction), in a long pulse stimulus scheme, as well as the spatial registration of thermal images after post-processing analysis to their visible counterpart, so as to obtain a fine resolution diagnostic map. As an exemplar case study, we report about the application of dual mode imaging with a 500 Formula: see text pixel size at object plane on the "Monocromo", a fresco by Leonardo da Vinci located in the Sforza Castle (Milan, Italy). Our technique was used to guide the conservators during the restoration works, opening new perspectives in artwork diagnostics.
The main objective of this review is to summarize and thoroughly investigate the most popular and promising BIM (building information modeling) and BEM (building energy modeling) interoperability ...strategies employed in the last years (2004–2023), highlighting pros and cons of each strategy and trying to understand the reason for the still limited BIM–BEM interaction. This review summarizes the main countries, areas, modeling tools, and interoperability strategies, with the advantages and disadvantages of each one. The methodology is based on the PRISMA protocol, and two databases were used for the research: Scopus and Google Scholar. A total of 532 publications were selected and 100 papers were deemed useful for the purposes of this review. The main findings led to the identification of four different interoperability strategies between BIM and BEM tools: (1) real-time connection; (2) standardized exchange formats and middleware corrective tools; (3) adherence to model view definitions; (4) proprietary tool-chain. These strategies were found to be characterized by different degrees of complexity, time required for information exchange, proprietary or opensource software, ability to reduce information loss, and detailed energy results. The results of this study showed that, to date, there is no better interoperability strategy, and that further efforts are needed so that interoperability between the two tools can become commonplace.
The evaluation of photovoltaic (PV) system's efficiency loss, due to the onset of faults that reduce the output power, is crucial. The challenge is to speed up the evaluation of electric efficiency ...by coupling the electric characterization of panels with information gathered from module diagnosis, amongst which the most commonly employed technique is thermographic inspection. The aim of this work is to correlate panels' thermal images with their efficiency: a "thermal signature" of panels can be of help in identifying the fault typology and, moreover, for assessing efficiency loss. This allows to identify electrical power output losses without interrupting the PV system operation thanks to an advanced PV thermography characterization. In this paper, 12 faulted working panels were investigated. Their electrical models were implemented in MATLAB environment and developed to retrieve the ideal I-V characteristic (from ratings), the actual (operative) I-V characteristics and electric efficiency. Given the curves shape and relative difference, based on three reference points (namely, open circuit, short circuit, and maximum power points), faults' typology has been evidenced. Information gathered from infrared thermography imaging, simultaneously carried out on panels during operation, were matched with those from electrical characterization. Panels' "thermal signature" has been coupled with the "electrical signature", to obtain an overall depiction of panels' health status.
Appropriate daylight control could maximize occupants’ visual comfort, potentially saving energy. However, the deployment of daylight control systems (DLCSs) is not happening, mainly due to the ...complex system calibration and the frequent reluctance of occupants toward automatic control systems that exclude their participation. In this paper, a human-in-the-loop DLCS is presented. The system is designed to allow the users to have direct interaction via smartphone Bluetooth communication, enabling them to set the lighting values deemed most comfortable nimbly. Special attention has been paid to the power consumption of the DLCS, especially in standby mode. Accessibility of configuration has been taken into consideration, leading to the choice of a wireless configured device. The performance of the prototype DLCS was evaluated experimentally in a side-lit room and compared with that of a commercial controller. The illuminance on a reference work plane was measured during the operation of the systems to observe the controllers’ effect on the lamp’s luminous flux while simultaneously considering the variation of daylight conditions. Moreover, the energy performance of the systems was studied to obtain information about the energetic effectiveness and convenience of the studied DLCSs. The main results showed that the proposed system could maintain the required target illuminance values on the work plane as daylight conditions vary: the maximum deviation measured using the prototype never exceeded 11 lx. In comparison, the commercial controller reached peaks of 220 lx. Moreover, the energy consumption of the prototype (resulting equal to 370 mVA) was lower than the consumption of the commercial system (equal to 600 mVA), allowing for increased energy savings over the long period. The more straightforward configuration allows the user to better interact with the DLCS.
The building sector is a major contributor to the world's energy consumption, exhibiting an ever-increasing trend. Heat losses through the building envelope constitute the most significant factor. ...Furthermore, the construction process has seen limited technological advancements in recent years, remaining heavily reliant on manual labor. Additive manufacturing emerges as a promising approach, with applications in the building sector on the rise. However, research on the thermal performance of 3D-printed components remains limited. Despite its recent introduction in the construction industry, 3D printing has yet to attain a level of maturity commensurate with other established methods.
This paper aims to reduce this gap by analyzing 3D-printed blocks from a heat transfer perspective. The article introduces two key innovations. Firstly, it explores the design of various internal geometries and air gaps aimed at minimizing heat flux exchange between block surfaces. Secondly, it presents an experimental study conducted with a custom-designed setup tailored for testing 3D printed blocks. The blocks are constructed using recyclable plastic material and feature different internal geometries based on hexagonal cells. While the plan size of the cells remains consistent, their vertical structures vary as follows: 1) Block 1: Hexagonal air cavities without horizontal partitions. 2) Block 2: Hexagonal air cavities with three horizontal partitions, dividing the cells vertically into four parts. 3) Block 3: Honeycomb structure characterized by three horizontal partitions and staggering along the vertical axis.
Their performance was experimentally evaluated using the Hot Box method, heat flow meter sensors, and infrared thermography. The results demonstrated reductions of up to 11.5 % in terms of thermal transmittance (U-value) with the inclusion of horizontal partitions. Starting from a U-value of 1.22 ± 0.04 W/m2K (Block 1), a transmittance of 1.08 ± 0.04 W/m2K was achieved for the honeycomb structure with horizontal partitions (Block 3).
•The potential of 3D printing to make energy-efficient blocks has been explored.•Various internal geometries of the air cavities of the blocks have been examined.•Experiments were conducted using Hot Box, heat flux meters, and infrared thermography.•Geometry inspired by honeycomb engineering gave the best transmittance value.•Results showed the potential of 3D printing to create complex, energy-efficient geometries.
The eye lens is a unique organ as no cells can be replaced throughout life. This makes it decisive that the lens is protected against damaging UV-radiation. An ultraviolet (UV)-absorbing compound of ...unknown identity is present in the aqueous humor of geese (wild and domestic) and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as "compound X", was fractionated and examined using a variety of spectroscopic techniques including LC-MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective "compound X". It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.
In recent years, experimental tests related to building components through laboratory facilities have relatively matured. The techniques are based on one-dimensional heat transfer by creating a ...permanent temperature difference over a specimen to control heat fluxes. The three main methods are the Guarded Hot Box (GHB) method, the Calibrated Hot Box (CHB) method, and the Heat-Flow Meter method (HFM). The HFM method is the most widely applied technique for measuring on-site U-values of building components and several scientific works stressed the need for high temperature differences between the environments, suggesting 10 °C or 15 °C. However, temperature stability and high temperature gradients are difficult to obtain, especially for Mediterranean climatic conditions. Starting from this, an experimental study was conducted through a GHB apparatus, setting temperature differences from 2 °C to 20 °C between the hot and cold chambers. Heat flow measurements were performed to compute the thermal conductance of a specimen characterized by a known stratigraphy, thus highlighting the effect of the low thermal gradient on data acquired by the heat flow sensor. It was found that, even for low temperature differences (2 °C) maintained by ensuring stable thermal conditions, the experimental results are comparable with those obtained for higher and usual temperature differences (20 °C).
In this paper, a novel integrated measuring and control system for hot box experiments is presented. The system, based on a general-purpose microcontroller and on a wireless sensors network, is able ...to fully control the thermal phenomena inside the chambers, as well as the heat flux that involves the specimen wall. Thanks to the continuous measurements of air and surfaces temperatures and energy input into the hot chamber, the thermal behavior of each hot box component is analyzed. A specific algorithm allows the post-process of the measured data for evaluating the specimen wall thermal quantities and for creating 2D and 3D thermal models of each component. The system reliability is tested on a real case represented by a double insulating X-lam wall. The results of the 72 h experiment show the system’s capability to maintain stable temperature set points inside the chambers and to log the temperatures measured by the 135 probes, allowing to know both the U-value of the sample (equal to 0.216 ± 0.01 W/m2K) and the thermal models of all the hot box components. The U-value obtained via hot box method has been compared with the values gathered through theoretical calculation and heat flow meter measurements, showing differences of less than 20%. Finally, thanks to the data postprocessing, the 2D and 3D thermal models of the specimen wall and of the chambers have been recreated.
In this work, a Guarded Hot Box (GHB) was employed to evaluate the effects of environmental boundary conditions on the internal surface thermal resistance of a wall. For this purpose, the study was ...carried out through an experimental setup to measure temperature - surface and ambient - in the two chambers of the GHB and air velocity near the specimen wall in the hot chamber. The experimental analysis together with the analysis of the dimensionless parameters allowed to determine the internal convective coefficient for different air speeds. To evaluate the results obtained with the proposed methodology, some existing correlations for the determination of the convective coefficient were used. Moreover, the measurement of the emissivity of sample surface and baffle, and the determination of the mean radiant absolute temperature allowed to calculate the radiative coefficient. Therefore, the internal surface thermal resistance with different air velocities, given by the combination of convective and radiative heat transfer, was determined, and compared with the value offered by the standard ISO 6946.
•Influence of environmental boundary conditions on walls surface thermal resistance.•Assessment of the convective heat transfer in function of the air speed through GHB.•Comparison between experimental data and conventional values provided by ISO6946.
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•Endothermic events were discovered both in pure and modified HDPE samples.•A pseudo-static matrix reconstruction algorithm applied to IRT data was used.•Thermocouples monitored the ...temperature variation in time during the tensile tests.•The UV optical transparency in the modified HDPE increased after the tensile test.•Numerical and experimental temperature variations follow similar trends in time.
The use of recycled paper in HDPE (High Density PolyEthylene) matrix composites has recently been introduced as an interesting alternative to traditional recycling process for paper. HDPE is also used as double wall greenhouse glazing because panels are easy to install, UV stabilized, and affordable. These type of products must also be strong enough and durable in order to react under tensile loads provided by wind and harsh weather conditions.
An interesting idea may be the insertion via injection moulding of chopped basalt and waste paper – i.e., two natural products – in pure HDPE samples. It completely follows the environmental sustainability concept centred on the triple “re”, i.e., recycle, reuse and reduce.
The research presented herein starts with a Differential Scanning Calorimetry (DSC) inspection of pure HDPE and HDPE mixed with 5% by weight of waste paper plus 5% by weight of chopped basalt as fillers in order to obtain an insight related to the temperature at which possible thermal events (endothermic or exothermic) occur. The dog-bone samples were also inspected under UV conditions (380nm) before and after tensile tests. The latter approach was simulated firstly by Comsol Multiphysics® computer program, and secondly recorded in real time via thermographic inspections.
The temperature variation in a region of interest (ROI) selected at the centre of the samples was mapped in the time during the inspection by infrared thermography (IRT) method using a pseudo-static matrix reconstruction algorithm realized in Matlab® environment. Instead, the combined use of thermocouples aimed at emphasizing the knowledge of the heat transfer in the time due to the mechanical stress applied at the borders of the inspected samples.
The aim was to understand whether modified HDPE can (or cannot) be a valid competitor of pure HDPE for the production of semi-transparent and robust panels.
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