The capability of capacitive sensors in the monitoring relative humidity in hypogeum environments

Hypogeum environments are characterized by high levels of relative humidity (RH). Most humidity sensors currently in use are based on the capacitive effect of the dielectric material to change according to water vapour uptake. In hypogeum environments the dielectric material can be saturated by water vapor, implying a significant error in the RH measurement. To improve the capacity of this type of humidity sensors, a modified hygrometer capacitive sensor, which uses a heating cycle to avoid the condensation, has been recently developed by Rotronic®. During four field campaigns in two different hypogea environments (the Monkey Tomb in Siena and the Mithreum of Caracalla Baths in Rome), RH was measured using the conventional capacitive sensor (CCS) and the heated capacitive sensor (HCS). The purpose of this study was to investigate the capability of HCS to detect RH variations when the environmental conditions were close to vapor saturation. Significant differences were found between the measurements of the two sensors: when RH was close to 100%, the CCS was not able to detect the RH decrease, giving only a measure of RH=100%, while HCS detected such a RH decrease. Therefore, these results encourage the use of HCS in the monitoring of RH levels in extreme humidity sites such as hypogea sites

CleAir monitoring system for particulate matter. A case in the Napoleonic Museum in Rome

Monitoring the air particulate concentration both outdoors and indoors is becoming a more relevant issue in the past few decades. An innovative, fully automatic, monitoring system called CleAir is presented. Such a system wants to go beyond the traditional technique (gravimetric analysis), allowing for a double monitoring approach: the traditional gravimetric analysis as well as the optical spectroscopic analysis of the scattering on the same filters in steady-state conditions. The experimental data are interpreted in terms of light percolation through highly scattering matter by means of the stretched exponential evolution. CleAir has been applied to investigate the daily distribution of particulate matter within the Napoleonic Museum in Rome as a test case

Performance assessment of hygrothermal modelling for diagnostics and conservation in an Italian historical church

The hygrothermal modelling of historical churches is a promising approach to study preservation issues and suitable retrofit measures. However, difficulties can arise in the use of Heat, Air and Moisture (HAM) models, which are often customised objects to be integrated into validated building energy simulation (BES). This research outlines a multi-step methodology to investigate the capability of a BES software coupled with a HAM model (BES + HAM) as a technique for diagnostics and conservation in complex settings. The 17th-century church of Santa Rosalia (Italy) was used as a historical site in a real context. As first step, the performance of the simulation tool was analysed through standardised exercises aiming at excluding incorrect assumptions and calculations in the HAM model (HMWall). Secondly, a building model of the church using a 1D heat transfer model (named building model A) was compared with one using HMWall (named building model B) in terms of the accuracy of the indoor climate simulations against hygrothermal measurements. The results showed that building model B enhanced the simulation accuracy by +50% with respect to building model A. Finally, annual simulations inside the church were run to further compare the seasonal trends of indoor climate scenario obtained from the two building models. Building model B allowed to study the water content distribution inside the altarpiece and a wall partition, showing that BES + HAM tools can be used to identify potential moisture-induced conservation risks

Mechanical properties of the most common european woods: A literature review

Wood is an orthotropic material used since ancient time. A literature research about the mechanical properties of density, fracture toughness, modulus of elasticity, and Poisson’s ratio has been done to have a broader view on the subject. The publications relating to the topic were found through the two search engines Scopus and Google Scholar that have yielded several papers, including articles and book sections. In general, there is no standardization on the method of analysis carried out on wood, underlining the great difficulty in studying this complex material. The parameter of density has a great variability and needs a deeper investigation; fracture toughness is not always available in literature, not even in the different directions of the wood sample. Interesting is the modulus of elasticity, which provides a correlation with density, especially in longitudinal section but, again, it needs to be studied in detail. The parameter of Poisson’s ratio is provided as single values in three different directions, but mainly for softwood. All the parameters require a more in-depth study for both softwood and hardwood. Furthermore, the type of analysis, whether experimental or modelling, needs to be standardized to have more comparable results

Climate-induced conservation risks of historic reinforced concrete buildings: Preliminary results from literature review

Environmental conditions can favour different kinds of deterioration in historic reinforced concrete structures. This preliminary results from literature review are focused on the climate-induced risks affecting reinforced concrete buildings with respect to mechanical, chemical, and biological deterioration. To this purpose, a three-step process defined by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram, was used leading to the inclusion of 45 documents identified via the search engines Scopus and Web of Science. The outcomes highlight that chemical and mechanical decays are the most investigated ones, being mainly triggered by salt weathering and freezing-thawing cycles. It was found that experimental and theoretical approaches are often coupled to estimate climate-induced deterioration mechanisms, also considering environmental parameters. Finally, the literature search provides some milestones which can be used to evaluate gaps and research needs in the field of climate-induced conservative risks affecting reinforced concrete structures

HindIII(+/−) Polymorphism of the Y Chromosome, Blood Pressure, and Serum Lipids: No Evidence of Association in Three White Populations

n/

Gender-Related Differences in the Relationships Between Blood Pressure, Age, and Body Size in Prepubertal Children

n/

Preliminary study of the mechanical and hygrothermal performance of concrete reinforced with fibrillated cellulose

Cement, being the most widely used building material, is the responsible for a large share of greenhouse gas emissions. To reduce the environmental impact of its production, natural fibres can be used as eco-friendly additives. Moreover, their potential use in traditional lime-based mortars makes them an ideal choice for green buildings as well as for the retrofit of historical buildings. An innovative cementitious composite reinforced with fibrillated cellulose (hereafter called «green concrete») was tested to assess its mechanical and physical properties. Samples were casted using Portland cement and natural hydraulic lime and varying the ratios among the constituents. Viscosity and setting time of the fresh pastes were determined with a viscosimeter and a Vicat apparatus, while their hydration was studied by thermal analysis. The influence of the fibres on the flexural strength of the final composite was determined through mechanical tests. The expected hygrothermal performance of the «green concrete» was explored through dynamic hygrothermal simulation to investigate its potential use as a retrofit material. A sensitivity analysis (SA), based on the hygrothermal properties of natural-based building materials similar to the «green concrete», was conducted to identify the parameters influencing more the simulation of annual internal temperature and moisture variations. The preliminary assessment of the mechanical properties of the «green concrete» showed that at higher percentages the cellulose fibres can negatively affect the workability/setting time of the fresh pastes and the flexural strength. The most promising samples were identified and will undergo further investigation. The SA results outlined that the «green concrete» might not be effective for thermal insulation, although it might be used as a moisture-buffering layer by adjusting the values of the free water saturation moisture content, the equilibrium moisture content at RH=80% and the dry vapour diffusion resistance factor of the final composite