Recensione di Gordon McOuat and Larry Stewart, eds., Spaces of Enlightenment Science. Leiden: Brill, 2022.

Recensione di Gordon McOuat and Larry Stewart, eds., Spaces of Enlightenment Science. Leiden: Brill, 2022

Rivoluzione chimica o Antico Regime? Una nuova interpretazione del ritratto di Jacques-Louis David dei coniugi Lavoisier

In September 2021, two articles were published presenting the results of detailed analyses conducted during the restoration of Jacques-Louis David's portrait of Mr and Mrs Lavoisier. Based on this important work, the authors of the two essays formulated a new interpretation of the painting and suggested that in the first version, the main intention of David and his patrons was to depict an upper-class Parisian couple without any explicit reference to the scientific interests that later became central in the final version. In the present essay I put forward a different interpretation, emphasizing all the elements that bring continuity between the two versions of the painting, thus showing two complementary ways of representing the scientific activities carried out by the Lavoisiers at the Arsenal

Groundwater vulnerability assessment: from overlay methods to statistical methods in the Lombardy Plain area

Groundwater is among the most important freshwater resources. Worldwide, aquifers are experiencing an increasing threat of pollution from urbanization, industrial development, agricultural activities and mining enterprise. Thus, practical actions, strategies and solutions to protect groundwater from these anthropogenic sources are widely required. The most efficient tool, which helps supporting land use planning, while protecting groundwater from contamination, is represented by groundwater vulnerability assessment. Over the years, several methods assessing groundwater vulnerability have been developed: overlay and index methods, statistical and process-based methods. All methods are means to synthesize complex hydrogeological information into a unique document, which is a groundwater vulnerability map, useable by planners, decision and policy makers, geoscientists and the public. Although it is not possible to identify an approach which could be the best one for all situations, the final product should always be scientific defensible, meaningful and reliable. Nevertheless, various methods may produce very different results at any given site. Thus, reasons for similarities and differences need to be deeply investigated. This study demonstrates the reliability and flexibility of a spatial statistical method to assess groundwater vulnerability to contamination at a regional scale. The Lombardy Plain case study is particularly interesting for its long history of groundwater monitoring (quality and quantity), availability of hydrogeological data, and combined presence of various anthropogenic sources of contamination. Recent updates of the regional water protection plan have raised the necessity of realizing more flexible, reliable and accurate groundwater vulnerability maps. A comparison of groundwater vulnerability maps obtained through different approaches and developed in a time span of several years has demonstrated the relevance of the continuous scientific progress, recognizing strengths and weaknesses of each research

Effect of intermittent cathodic protection on potential and corrosion rate of carbon steel in soil simulating solution

Carbon steel in aerated soil operates in cathodic protection (CP) condition if the IR-free potential is more negative than –0.850 V CSE, which corresponds to a corrosion rate lower than 0.01 mm·a-1. CP is applied by a stationary current, which effectiveness depends on a thermodynamic effect, which reduces (or stops) corrosion rate, and on a chemical effect due to the alkalinisation at the metal-to-electrolyte interface. The increase of pH is promoted by the cathodic reactions (oxygen reduction and, at lower potential, hydrogen evolution) occurring on the polarized metal and can promote passive condition. In this paper, a preliminary study of intermittent CP has been carried out in order to investigate the effect of a temporary current interruption on potential monitoring and on residual corrosion rate of steel in soil simulating solution. Test has been performed applying two cathodic current densities (0.2 and 1.0 A·m-2), varying the current-off period daily duration (6, 12 and 16 hours) and monitoring weekly the potential. During the on period (i.e. CP on), oxygen is consumed and alkaline pH is established; during the off period (i.e. when CP is interrupted), the alkalinity and the slow oxygen replacement assure corrosion rates lower than in free corrosion condition, especially if high cathodic current density is previously applied

Can an intermittent cathodic protection system prevent corrosion of buried pipeline?

Carbon steel pipelines are provided with corrosion prevention systems, namely an insulating coating and a cathodic protection (CP) system that reduces corrosion rate below 10 μm/a. CP is applied by a stationary cathodic current, which effectiveness on the metal surface is twofold: oxygen consumption and alkalinization (pH > 10) at the metal-to-electrolyte interface. The increase of pH is beneficial, promoting passive condition. In this paper, a preliminary study of the effect of intermittent CP has been carried out in order to investigate the effect of a temporary current interruption on the potential monitoring and on the residual corrosion of the metal. During the on period, oxygen is consumed and alkaline pH is established, during off period, the alkalinity and the slow oxygen replacement assure corrosion rates lower than in free corrosion condition. Test has been performed both in normal and overprotection condition, varying the off period duration, monitoring weekly the protection potential

Laboratories and Technology: From Temples to Workshops: Sites of Chemistry in Ancient Civilizations

Survey of the workshop equipment in the Babylonian, Egyptian and Graeco-Roman tradition

SAFETY AND HEALTH SITE INSPECTIONS FOR ON-FIELD RISK ANALYSIS AND TRAINING

The field of construction is always affected by a large number of accidents at work that have many different causes and responsible. Therefore, it is of utmost importance to focus on all these issues, in order to reduce all risk factors that can undermine individuals’ safety on building sites. The objective of the research is then the development of a method for quick on site analysis of all critical issues that can create accidents and identification of the related causes in order to directly provide a correct and focused training identified as the best method to act on the causes to reduce accidents. The research was carried on during construction of the Universal Exhibition of Milan – Expo 2015 – that counted almost 70 contemporary construction sites. To reach the goals further research steps has been followed and in particular: (i) inspections on building sites through all the Expo area; (ii) analysis of the main identified problems; (iii) development of a methodology to quickly identify the cause of problems; (iv) validation of the method through back office analysis of site documents; (v) correct on-site training according to found problem. During the whole construction site, the improvements in criticalities solving have been visible thanks to the focused training. The developed method, carried on in a high-risk environment, is applicable in any other building sites and environment as independent from the boundary conditions of the place

Theory and Concepts: The Mythological Foundation of Chemical Theories in Ancient Civilizations

Survey of ancient chemical theories in Egypt, Mesopotamia, and in the Graeco-Roman Worl