Development of a Unified IoT Platform for Assessing Meteorological and Air Quality Data in a Tropical Environment.

In developing nations, outdated technologies and sulfur-rich heavy fossil fuel usage are major contributors to air pollution, affecting urban air quality and public health. In addition, the limited resources hinder the adoption of advanced monitoring systems crucial for informed public health policies. This study addresses this challenge by introducing an affordable internet of things (IoT) monitoring system capable of tracking atmospheric pollutants and meteorological parameters. The IoT platform combines a Bresser 5-in-1 weather station with a previously developed air quality monitoring device equipped with Alphasense gas sensors. Utilizing MQTT, Node-RED, InfluxDB, and Grafana, a Raspberry Pi collects, processes, and visualizes the data it receives from the measuring device by LoRa. To validate system performance, a 15-day field campaign was conducted in Santa Clara, Cuba, using a Libelium Smart Environment Pro as a reference. The system, with a development cost several times lower than Libelium and measuring a greater number of variables, provided reliable data to address air quality issues and support health-related decision making, overcoming resource and budget constraints. The results showed that the IoT architecture has the capacity to process measurements in tropical conditions. The meteorological data provide deeper insights into events of poorer air quality.

Reliability Testing of a Low-Cost, Multi-Purpose Arduino-Based Data Logger Deployed in Several Applications Such as Outdoor Air Quality, Human Activity, Motion, and Exhaust Gas Monitoring.

This contribution shows the possibilities of applying a low-cost, multi-purpose data logger built around an Arduino Mega 2560 single-board computer. Most projects use this kind of hardware to develop single-purpose data loggers. In this work, a data logger with a more general hardware and software architecture was built to perform measurement campaigns in very different domains. The wide applicability of this data logger was demonstrated with short-term monitoring campaigns in relation to outdoor air quality, human activity in an office, motion of a journey on a bike, and exhaust gas monitoring of a diesel generator. In addition, an assessment process and corresponding evaluation framework are proposed to assess the credibility of low-cost scientific devices built in-house. The experiences acquired during the development of the system and the short measurement campaigns were used as inputs in the assessment process. The assessment showed that the system scores positively on most product-related targets. However, unexpected events affect the assessment over the longer term. This makes the development of low-cost scientific devices harder than expected. To assure stability and long-term performance of this type of design, continuous evaluation and regular engineering corrections are needed throughout longer testing periods.

A dataset of high-resolution synchrotron x-ray photoelectron spectra of tarnished silver-copper surfaces before and after reduction with a remote helium plasma at atmospheric pressure.

The data presented in this article are related to the measurements in the contribution titled: 'Tarnished silver-copper surfaces reduction using remote helium plasma at atmospheric pressure studied by means of high-resolution synchrotron x-ray photoelectron microscopy' published in Corrosion Science. X-ray photoelectron spectra were collected from pure silver, sterling silver (92.5 w% Ag and 7.5 w% Cu) alloy and pure copper. These metals were artificially sulphidised. A remote helium plasma at atmospheric pressure was applied on the metallic and sulphidised state. Then the top layer of the 4 surface states were analysed at the NanoESCA beamline (Electron Spectroscopy for Chemical Analysis at the Nanoscale) at Elettra Sincrotrone Trieste. The instrument installed as an end station at the NanoESCA beamline of the Elettra storage ring combines an electrostatic Photo Electron Emission Microscope (PEEM) with a double-hemispherical ('IDEA') analyser, allowing the collection of photoemission electron microscopy (PEEM) images, X-ray photo electron-energy-filtered images and XPS spectra. The NanoESCA beamline provides electromagnetic radiation with variable polarization (linear, circular) and energies up to 1000 eV. Information for Cu3p, Cl2p, S2p, C1s and Ag3d were obtained by collecting spectra at 450 eV. The goal of the analyses was to determine how the plasma treatment changed the top layer of the metallic and sulphidised surface of pure silver, sterling silver and pure copper. This contribution focuses on the calibration of the collected XPS spectra, as well as the impact of the plasma treatment on the surface states.

Real-Time Wood Behaviour: The Use of Strain Gauges for Preventive Conservation Applications.

Within the heritage field, the application of strain gauges on wood surfaces is a little-explored but inexpensive and effective method to analyse the environmental appropriateness of rooms for the wooden heritage collections they contain. This contribution proposes a wood sensor connected to a data logger to identify short moments with an elevated risk of harm. Two experiments were performed to obtain insights pertaining to the applicability of wood sensors to evaluate preservation conditions. (1) The representativeness of strain gauges on dummies was tested for their use in evaluating the preservation conditions of a range of wooden objects exposed to the same environment. For this, three situations were mimicked: a bare wood surface, a wood surface covered with a preparation layer, and a wood surface covered with a preparation and varnish layer. (2) The usability of strain gauges to monitor the wood behaviour in real-time measurements was tested with a monitoring campaign of almost two years in a church where a new heating system was installed. The results of both experiments are promising, and the authors encourage a broader application of strain gauges in the heritage field.

Exploring the possibility of radiography in emission mode at higher energies: Improving the visualization of the internal structure of paintings / Explorando las posibilidades de la radiografía en modo de emisión a altas energías: Cómo optimizar la visualización de la estructura interna en pinturas

Summary We demonstrated in previous investigations that the internal structure of paintings can be visualized with conventional radiography in transmission mode when paintings have the proper stratigraphy. Unfortunately, there are many paintings that do not result in useful images. This problem can be solved by using radiography in emission mode. With this technique, the painting is irradiated with high energetic X-rays originating from an X-ray tube operating at 100 keV - 320 keV while inside the painting low energetic signals such as photoelectrons or characteristic photons are being generated. These signals escape from the top 10 µm of the painting and are able to illuminate the imaging plate. However, this technique has also some disadvantages. One of them is that it is not able to visualize underlying paintings. In this study, we explored the possibility to enhance the information depth by increasing the energy of the photon source from 100 keV up to 1.3325 MeV (i.e., 60Co source). At the same time, we also studied how the contrast between pigments is generated in emission mode. For this, we used mathematical simulation of particle transport in matter to understand the relation between input particle (particle type such as photon, electron or positron and the energy of the particle), the material being irradiated (element from which it is composed, thickness and density) and the output signal (generated particle types and energy). Finally, we will show that it is possible to image paintings using a 192Ir and even a 60Co source.

Resumen En investigaciones previas se ha demostrado que la estructura interna de las pinturas se puede visualizar satisfactoriamente con la radiografía convencional en modo de transmisión, siempre y cuando dichas pinturas tengan la estratigrafía adecuada. Desafortunadamente, hay muchos casos en los que la aplicación de este método no resultan en imágenes útiles. Este problema puede ser resuelto usando la radiografía en modo de emisión. Con esta técnica, la pintura se irradia con rayos X de alta energía originados en un tubo de rayos X trabajando entre 100 keV y 320 keV. Esto genera señales de baja energía (fotoelectrones o fotones característicos) en el interior de la pintura que, al escapar de las 10 μm superiores, pueden iluminar una placa de imágenes. No obstante, su aplicación también implica ciertas desventajas. Una de ellas es la incapacidad de visualizar las pinturas subyacentes. En este estudio, exploramos la posibilidad de incrementar la información obtenida a mayores profundidades aumentando la energía de la fuente de fotones desde 100 keV hasta 1.3325 MeV (fuente de 60Co). También estudiamos el impacto de esta energía en el contraste obtenido entre los pigmentos. Para esto, utilizamos la simulación matemática del transporte de partículas en la materia para comprender la relación entre partículas de entrada (fotones, electrones o positrones y la energía de las partículas), el material que se irradia (elemento del que está compuesto, espesor) y la señal de salida (tipos de partículas generados y energía). Finalmente, mostraremos que es posible crear imágenes de pinturas usando una fuente 60Co.

Electrochemical photodegradation study of semiconductor pigments: influence of environmental parameters.

Chemical transformations in paintings often induce discolorations, disturbing the appearance of the image. For an appropriate conservation of such valuable and irreplaceable heritage objects, it is important to have a good know-how on the degradation processes of the (historical) materials: which pigments have been discolored, what are the responsible processes, and which (environmental) conditions have the highest impact on the pigment degradation and should be mitigated. Pigment degradation is already widely studied, either by analyzing historical samples or by accelerated weathering experiments on dummies. However, in historic samples several processes may have taken place, increasing the complexity of the current state, while aging experiments are time-consuming due to the often extended aging period. An alternative method is proposed for a fast monitoring of degradation processes of semiconductor pigments, using an electrochemical setup mimicking the real environment and allowing the identification of harmful environmental parameters for each pigment. Examples are given for the pigments cadmium yellow (CdS) and vermilion (α-HgS).

Possibilities of energy-resolved X-ray radiography for the investigation of paintings.

X-ray radiographic images of paintings often show little or no contrast. In order to increase the contrast in radiographic images we measured the X-ray spectrum of a low power X-ray tube, after passing through the painting, with a high energy-resolution SDD detector. To obtain images, the detector is collimated with a 400 µm diameter pinhole and the painting was moved through the beam in the x and y-direction using a dwell time of a few seconds per pixel. The data obtained consists of a data cube of, typically, 200 × 200 pixels and a 512-channel X-ray spectrum for each pixel, spanning the energy range from 0 to 40 keV. Having the absorbance spectrum available for each pixel, we are able, a posteriori, to produce images by edge subtraction for any given element. In this way high contrast, element-specific, images can be obtained. Because of the high energy-resolution a much simpler edge subtraction algorithm can be applied. We also used principal-component imaging to obtain, in a more automated way, images with high contrast. Some of these images can easily be attributed to specific elements. It turns out that preprocessing of the spectral data is crucial for the success of the multivariate image processing.