Development of a new device for the measurement and modeling of an innovative risk index for cultural heritage application

The monitoring, as a function of time, of environmental parameters in cultural heritage is essential to preserve materials, to recognize the reasons of degradation and to evaluate their effects. The degrading effects of objects in cultural heritage field, can be classified in optical, morphological, physical-chemical/mechanical and alterations and depend by micro-climatic conditions. For this reason, in recent years, several solutions have been developed and commercialized for environmental monitoring, some compatible with general advice and others OEM (Original Equipment Manufacturing). However, the trend of application between compliant and non-ISO-compliant devices has not yet been sufficiently analyzed. In this first section, we show how in the last ten years researchers have shifted their attention to custom-made devices based on new generation sensors despite the expense of units ISO certified. The study based on a review of scientific articles has shown that: with the increase of low-cost and open-source technologies applied in the Environmental Impact Assessment (EIA) and in particular in the cultural heritage, led to a research advancement in the field, but, at the same time, increased non-homogeneity of the methods, impinging comparability of results. In recent years the trend is to use low-cost automatic wireless systems. This innovation, however, opens new scenarios and challenges on how to improve their stability, longevity, and sensitivity; reduce maintenance (battery replacement, including calibration or sensors); improve data analysis/management/display costs. In particular, it has highlighted the current difficulty of low-cost detectors to satisfy the robustness and reliability of regulatory and conventional stationary monitors at the expense of the periods and aesthetics. We have therefore paid particular attention to the sensitivity and reliability of the innovative solutions presented to overcome the traditional limitations, as well as to the real feasibility of solutions regarding sustainability, adaptability to the works of art or price. We also see the need for more communication between the scientific community and the decision-makers, who have only recently opened up to this paradigm. We highlighted the need to identify recurrent or innovative topics in the various documents concerning the approaches to preventive conservation, the preservation of damage and environmental management. After a review of state of the art regarding the different sampling device applied in cultural heritage and a survey of the parameters that involve a degradation effect on the materials, in this section, we focus our attention on a sensors-based prototype able to detect: (i) temperature and relative humidity; (ii) NO, NO2 and SO2; (iii) vibrations. In particular, this section describes the design and the validation of the Wireless Sensor Network (WSN) propose3, named WENDY, an acronym for Wireless Environmental moNitoring Device prototYpe. WENDY, built on a microcontroller of ATmega328P series, gathers signals from a sensor for temperature and relative humidity; a 9-axis MIMU; and three gas detection miniature boards (NO, NO2 and SO2). Complete the board a connector for memory card (SD) and an RTC. Additionally, a module based on the ZigBee standard could be used to transmit all data. In this section, precisely, we present the performances of the WSN node in detecting: structure tilt, vibrations and the daily cycle of humidity, temperature and gas deposition. The experimental setup used to evaluate the accuracy of MIMU system highlighted a relative error on shock acceleration measurement, in term of normalized root mean square error, lower than 0.1 % for the sinusoidal input and 0.51 % for cardinal sin input, with an average accuracy in the principal peak reconstruction of 1 % in the chosen frequency range (5 Hz to 50 Hz). The MIMU accuracy for tilt measurement, evaluated through the root mean square error was equal to 0.3° and a standard deviation always lower than 0.4° in the 0-90° tilt range. The gas detection and temperature/ humidity boards showed data comparable with the nearby certified ARPA system device. The aim of the applicative section is monitoring effects of different factors which affect the “Minerva Medica Temple,” an archeological site in Rome. In particular, we focus on: (i) the seasonal thermal variations on the structure; (ii) the contamination due to by local traffic regarding gaseous pollutant and (iii) the dynamic response of the structure to a tramway line located in Rome and called “Roma- Giardinetti.” The developed system allows for prioritization of intervention both for management and interventions planning, regarding restoration, consolidation, and conservation. Moreover, the software structure of the environmental monitoring device is presented and expounded in detail.4 Always in this section, an innovative procedure for the evaluation of the environmental hazard in cultural heritage is proposed. This risk assessment can be considered as a “relative risk assessment methodology.” In particular, it considers the impacts of microclimatic conditions on the monument, based on the international norms and the current scientific knowledge. For measurement campaigns with WENDY, the risk method proposed is applied to the results of two measurement campaigns carried out between 2017 and 2018 over two different periods (September-December and March-July), at “Minerva Medica Temple,” in Rome

A Principal component analysis to detect cancer cell line aggressiveness

In this paper, we propose the use of Principal Component Analysis (PCA) as a new post-processing method for the detection of breast and bone cancer cell lines cultured in vitro using a microwave biosensor. MDA-MB-231 and MCF7 breast cancer cell lines and SaOS-2 and 143B osteosarcoma cell lines were characterized using a circular patch resonator in the 1 MHz – 3 GHz frequency range. The return loss of each cancer cell line was analyzed, and the differences among each other were determined through Principal Component Analysis according to a protocol previously proposed mainly for electrocardiogram processing and X-ray photoelectron spectroscopy. Our results showed that the four cancer cell lines analyzed exhibited peculiar dielectric properties when compared to each other and the growth medium, confirming that PCA could be employed as an alternative methodology to analyze microwave characterization of cancer cell lines which, in turn, may be deeply exploited as a tool for the detection of cancer cells in healthy tissues

PERMITTIVITY OF WOOD AS A FUNCTION OF WATER CONTENT

In the last ten years, the interest in safeguarding historical artifacts and buildings has considerably increased, thanks to the development of non-invasive and dedicated methodologies and technologies. In particular, the measurement of water content in historical materials is an aspect of primary importance in numerous biological and mechanical degradation activities. Many historic structures and objects are wooden-made, despite the hygroscopic nature of the material. Different studies show how the water adsorption phenomenon principally occurs in the range of 0% to 25%. In this range, changes in the water content affect the physical-mechanical and rheological properties of wood, and above 5% of moisture content risks for insect infestation increase. This paper proposes a study to determine the complex permittivity of moisturized wood samples at different levels of the water content (0% - 5% range)

Breast cancer cell lines detection by a microwave resonant sensor

In the last years, the measurement of materials’ dielectric properties has become a central issue for their impact on scientific research, such as for industrial, communication and environmental applications. Recently, various systems based on microwave biosensing achieved great benefits in healthcare and biomedical fields due to their minimal invasiveness, high versatility, and sensitivity. In addition, microwave sensors are able to measure living tissues dielectric properties through non-invasive scattering parameters. Changes in these factors, which are strictly related to the resonant frequency of the probe, could be crucial for monitoring or diagnosing possible pathological states. For example, the early detection of tumours is a critical part of cancer research for reducing the mortality rate. However, due to the complex and various signaling pathways involved in cancer development, there is a lack of knowledge on tumor behavior

WENDY: a Wireless Environmental Monitoring Device Prototype

Recent studies show how air quality monitoring activities are fundamental because the environment has always played a vital role in the life-cycle of an artwork/monument, due to interaction with the materials. For this reason, we propose and present a measuring device able to detects different parameters. The device is instrumented with a microcontroller that detects signals from an inertial sensor with nine degrees of freedom, a sensor for climate parameters, four gas sensors (SO2, O3, NO, NO2), a lux-meter and particles matter analyzer. The goal of this study is to realize a small- size and low-cost sensor system able to evaluate and classify the effects of different factors in an original way: through a global Risk Index. The proposed and projected system allows monitoring: (a) daily thermal variations; (b) the vibrations that occur on the structure and (c) pollutant – both reductant, oxidant and deposit agents. In this paper, the structure (hardware and software) of the environmental monitoring device is presented and expounded in detail. A Risk Analysis Algorithm is proposed and evaluated. It shows how the global degrading risk is always lower than the threshold level, even if the single compound could exceed its own threshold

Application of a novel monitoring technology at “Minerva Medica Temple” archaeological site in Rome

Environmental parameters monitoring is necessary to preserve materials, identify causes of degradation, and quantify their effects, as a function of time. In this research, we propose a measuring unit and present an example of collected data. The unit is based on an ATmega328P microcontroller, gathering signals from: a 9-axis MIMU; a sensor for temperature and relative humidity; and three gas detection miniature boards (NO, NO2 and SO2). The aim of the project is to monitor effects of different factors: (i) seasonal thermal variations; (ii) dynamic response of the structure and (iii) gaseous pollutant concentration. The developed system allows for a prioritization of intervention both for organization and management, and for interventions planning in terms of restoration, consolidation, and conservation

Permittivity of wood as a function of moisture for cultural heritage applications: a preliminary study

In this work, the evaluation of moisture content in historic wooden objects starting from permittivity measurements is investigated. For this purpose, a WR430 waveguide with a 1.7-2.6 GHz range was used to estimate the complex permittivity correlated to different moisture levels. Experimental tests were carried out on poplar (Populus nigra L.), a wood typically used in central Italy in the thirteenth-sixteenth centuries as a painting support. For the considered measurement system, experimental results and calibration curves are reported

Validation and application of a novel solution for environmental monitoring: a three months study at “minerva medica” archaeological site in rome

Monitoring of environmental parameters is necessary to preserve materials, identify causes of degradation, and quantify their effects, as a function of time. In this research, we propose a measuring unit and present an example of collected data. The unit is based on an ATmega328P microcontroller, gathering signals from: a 9-axis MIMU; a sensor for temperature and relative humidity; and three gas detection miniature boards (NO, NO2and SO2). The aim of the project is to monitor the effects of different factors: (i) seasonal thermal variations; (ii) dynamic response of the structure and (iii) gaseous pollutant concentration. The developed system allows for a prioritization of intervention both for management and interventions planning, in terms of restoration, consolidation, and conservation. The experimental setup used to evaluate the accuracy of MIMU system highlighted a relative error on shock acceleration measurement, in term of percent root mean square error, lower than 0.36 for the sinusoidal input, and 0.49 for cardinal sin input, with an average accuracy in the principal peak reconstruction lower than 2% in the chosen frequency range (5 Hz to 50 Hz). Data collected in situ showed a maximum frequency of vibration, at ground level, equal to 40 Hz with a peak of 8 mm/s. The gas detection and temperature/humidity boards showed data comparable with the closest certified ARPA system device

Development of wireless sensor network for museum environmental monitoring

Wireless Sensor Network (WSN) has been adopted in many contests, such as healthcare or industrial. In museum scenario, WSN has been introduced for environmental monitoring, to control temperature and relative humidity. Nowadays, the development of low-cost micro-scale sensing units, opened to new possibilities for WSN development, including other environmental measurements of interest, such as: gaseous pollutant, relative humidity, temperature, light intensity, air flow, vibration. The present work is part of the overarching goal of the development of a low-cost and minimally invasive WSN designed for a museum scenario. The here proposed WSN node, based on a ZigBee-IEEE802.15.4 standard, gathers signals provided by: a 9-axis MIMU, a sensor for temperature and relative humidity, and a lux-meter. In this paper, we present performances of the WSN node in detecting structure tilt that can be due to structure deformations and/or seismic vibrations