INNOVATIVE METHODOLOGIES TO REMOVE STAINS FROM STONE SURFACES BASED ON NATURAL PRODUCTS

Participation of the authors at the National Smart Cities project (SCN 00520) was focused on proposing ecological innovative materials to restore stone cultural heritage. The shift from synthetic to natural compounds is a general trend, especially in the field of cultural heritage where the use of the former ones resulted in dangers for environment and restorer's health. Looking at this aim we paid our attention to two natural proteins, lactoferrin and ovotransferrin, identified and tested for the removal of iron-based stains on marble surfaces ensuring a safe cleaning method able to reduce professional diseases and pollution. The two proteins, of which is well known the ‘in vivo’ high affinity for iron, were firstly extracted in our lab from their natural matrices. The protein extracts were then gelled using a common cellulose pulp. The obtained gels were spread on the iron-stained surfaces and, once their action fulfilled, promptly removed. Comparative surface analysis by XPS of marble samples (a: white; b: long-time rusted and c: 'b' treated with gelledproteins) shows the complexing reactivity of both proteins. Their efficacy, visually confirmed by the spectrocolorimetric analysis, is discussed in the light of the curve fitting results of all the detailed spectra

An Open-Source, Low-Cost Apparatus for Conductivity Measurements Based on Arduino and Coupled to a Handmade Cell

Electrical conductivity is one of the main parameters for the characterization of water solutions and for the monitoring of water sources. In this paper, we describe a very inexpensive prototype for conductivity measurements based on Arduino UNO R3 coupled to an open-source circuit board with only passive components. We designed the printed circuit board (PCB) and the suitable handmade cell using stainless-steel electrodes and wrote the freeware management software; the assembly of the prototype, including a temperature probe, and results were relatively simple. In order to allow for replicates, the instrument design, schematics, and software are available with an open-source license. Thirty-one bottles of spring waters with conductivities of between 15.2 and 2000 µS cm−1 were tested using both this prototype and a commercial conductivity meter. Data correlation produced an equation that allowed us to obtain the conductivity value, starting with the value furnished by the Arduino apparatus in arbitrary units. The prototype is accurate enough (inaccuracy lower than 6% excluding very low conductivity values) and precise (RSD% of about 5%). Even if a lot of commercial instruments for conductivity are available, we propose a prototype built with the aim of lowering the cost of measurements, while ensuring that they remain useful for lab or in situ application, as well as for continuous water monitoring/management systems. A further aim was to propose the building of the instrument as a laboratory exercise; this can help students to better understand basic theoretical concepts regarding conductivity, electronic components, and the acquisition and treatment of analytical data

Simple Yeast-Direct Catalytic Fuel Cell Bio-Device: Analytical Results and Energetic Properties

This paper reports the analytical detection and energetic properties of a glucose-fed Direct Catalytic Fuel Cell (DCFC) operated in association with yeast cells (Saccharomyces Cerevisiae). The cell was tested in a potentiostatic mode, and the operating conditions were optimized to maximize the current produced by a given concentration of glucose. Results indicate that the DCFC is characterized by a glucose detection limit of the order to 21 mmol L−1. The cell was used to estimate the “pool” of carbohydrate content in commercial soft drinks. Furthermore, the use of different carbohydrates, such as fructose and sucrose, has been shown to result in a good current yield

Chemical-physical diagnostics propaedeutic to the conservative restoration of the Cippo Funerario of Quinto Cornelio Procliano

This paper describes some diagnostic analyses on a funus cippus, in precious white marble, located close to an ancient Roman consular road. Even if in good conservative conditions, it is almost completely covered by a black patina; so, a conservative intervention is planned, that will be directed by one of the authors, thanks to the financial support of the Cornelia Antiqua Association and the project's approval by Dr. Roberta Pardi of the Superintendence of Rome. The use of funerary cippus dates back to the Bronze Age. They were extensively used by Etruscans, both with figurative and symbolic contents, and by Romans in the republican period as an indication of burial or "in memory" of the deceased. Even if recycled materials such as broken columns, damaged pillars and quarry waste were used, only affluent families could afford a funus cippus. The simplest cippus are rectangular or trapezoidal stone blocks but richest ones include finely worked stones, in the shape of a pinecone or similar, with great use of archaic symbology. The absence of artistic interest is always compensated by the inscription, with the precise indication of the name of the deceased and his family, in some cases the only one reference available, as in the case of study; so, also the simplest cippus are heritage works to be preserved. During a first inspection, fragments of marble that had fallen due to exfoliation were collected and the points of detachment were identified; some samples of the inconsistent patina covering the cippus were also taken. A diagnostic steps was finally planned including on-site and in-lab analyses: a) measurement of the surface temperature and humidity by systematic sampling, b) colour measurements of the original marble in the exfoliatiated areas, c) macro photography for the identification of inconsistent areas, fractures, and possible recognition, by experts, of plant and animal species already evidenced by a simple visual analysis, d) a solutions, obtained as an extract of the taken patina (UNI-BBCC EN 16085: 2012) will be used for the analysis of soluble salts by Ionic Chromatography (Li, NH4, K, Na, Rb, Zn, Mn, Mg, Ca, Sr, Ba, F, Cl, Br, NO2, NO3, IO3, PO4, SO4, Acetate, Oxalate) following norms (UNI-BBCC EN 16455: 2014); e) on the same solution, pH, Redox potential and conductivity will be measured; f) measured by means of UV-Visible spectrophotometry, indexes of colour, organic substances and turbidity, g) preparation of shiny sections for observation and dimensional analysis of the thickness of the patinas with optical microscopy and electron microscopy (SEM) and elemental composition by EDS, h) statistical analysis of the results to highlight further anomalies due to degradation. Those diagnostics aims to identify of the degradation causes (UNI-BBCC 11182:2006) and then to guide the operations of cleaning, sterilization, consolidation and application of compatible protective agents

Simple Yeast-Direct Catalytic Fuel Cell Bio-Device: Analytical Results and Energetic Properties

This paper reports the analytical detection and energetic properties of a glucose-fed Direct Catalytic Fuel Cell (DCFC) operated in association with yeast cells (Saccharomyces Cerevisiae). The cell was tested in a potentiostatic mode, and the operating conditions were optimized to maximize the current produced by a given concentration of glucose. Results indicate that the DCFC is characterized by a glucose detection limit of the order to 21 mmol L−1. The cell was used to estimate the “pool” of carbohydrate content in commercial soft drinks. Furthermore, the use of different carbohydrates, such as fructose and sucrose, has been shown to result in a good current yield

Iron stains on paper. Can electrophoretic removal become an effective alternative to chemical cleaning?

<p>Research in restoration and conservation is directed vs. more sustainable working materials, methods and technologies. Electrophoretic removal, from porous material, of undesired stains due to charged species is theoretically an interesting alternative to chemical cleaning methods, but the lack of specific and comprehensive research work leads to controversial opinions about the efficiency and the needed harmfulness for the treated objects. In this work paper, samples with artificial rust stains were subjected to electrophoretic cleaning treatments in mineral water as electrolyte. Treatments were carried out either in a bath by complete sample immersion between the distanced electrodes or by sample wetting and sandwiching between the electrodes. Evaluation of cleaning efficiency and treatment effects was based on colour change measurements (image analysis of scanned paper samples before and after the treatment and by colorimetric data via spectrophotometric measurements), investigation of morphological changes by SEM observations and folding endurance measurements.</p