Deterioration status of asbestos-cement roofing sheets assessed by analyzing hyperspectral data

This paper describes a systematic procedure for recognizing corrugated asbestos-cement roofing sheets and evaluating their deterioration status related to the asbestos fiber air dispersion that can cause lung cancer. To develop this procedure, we made field and laboratory measurements and gathered airborne MIVIS data covering two industrial test areas in Italy.Laboratory analyses of asbestos-cement samples representing various levels of deterioration allowed for: (a) recognizing dominant minerals using XRD and FTIR instruments, (b) identifying their optical characteristics using portable field spectrometers (ASD and μFTIR), (c) assessing the abundance of surfacing asbestos fibers using a high resolution scanner.Based on the spectral analyses, two linear regression lines were identified by relating optical asbestos-cement material characteristics (i.e. band-depth ratio of the continuum removed calculated for the two asbestos diagnostic bands at 2.32 μm and at 9.44 μm) to the relative percentage of surfacing asbestos fibers related to AC deterioration status.Suitable MIVIS spectral regions were used in a spectral classification procedure to map asbestos-cement roofs. The detected roofs were further analyzed using the obtained linear regression lines to estimate surfacing asbestos fiber abundance, using the MIVIS TIR range at 9.44 μm, selected by means of the asbestos-cement detection limit analysis.The results showed that a hyperspectral scanner with suitable operational characteristics allows for good clustering of AC roofs as a function of their deterioration status. Therefore, this technique can furnish government authorities with an efficient, rapid and repeatable environmental mapping procedure that can provide information about the location of hazardous AC roofing sheets.     

Technical feasibility assessment of a solar chimney for food drying

Solar dryers use free and renewable energy sources, reduce drying losses (as compared to sun drying) and show lower operational costs than the artificial drying, thus presenting an interesting alternative to conventional dryers. This work proposes to study the feasibility of a solar chimney to dry agricultural products. To assess the technical feasibility of this drying device, a prototype solar chimney, in which the air velocity, temperature and humidity parameters were monitored as a function of the solar incident radiation, was built. Drying tests of food, based on theoretical and experimental studies, assure the technical feasibility of solar chimneys used as solar dryers for agricultural products. The constructed chimney generates a hot airflow with a yearly average rise in temperature (compared to the ambient air temperature) of 13 ± 1 °C. In the prototype, the yearly average mass flow was found to be 1.40 ± 0.08 kg/s, which allowed a drying capacity of approximately 440 kg.     

Towards a more effective and reliable salt crystallization test for porous building materials: state of the art

The durability of building materials with respect to salt crystallization is commonly determined by accelerated weathering tests, carried out in the laboratory. An effective laboratory weathering test should assess the durability and, in the case of conservation of historic buildings, the compatibility of repair materials with those existing. Besides, the test should provide reliable results within a reasonable period of time, accelerating the deterioration process without however altering its mechanism. Despite several national and international standards, recommendations and guidelines, a commonly accepted testing protocol does not yet exist. Researchers often develop and apply their own procedure, a fact that complicates comparison between different studies. The RILEM Technical Committee 271 ASC has been set up with the scope of developing improved test procedures for the assessment of the behaviour of materials under the influence of salt crystallization, which should overcome the limitations of existing standards and recommendations. This paper constitutes one of the first results of the work of the Technical Committee. It critically reviews the literature on salt crystallization tests, identifies advantages and limitations of the several test protocols and provides new ideas for the development of improved salt crystallization procedures.     

From egg yolk/κ-Carrageenan dispersions to gel systems: Linear viscoelasticity and texture analysis

The effect of pH (3.5–6) and polysaccharide concentration (0–0.5 wt%) on the linear viscoelastic behaviour of egg yolk/κ-Carrageenan (EY/κC) mixtures in aqueous solution was studied by using Small Amplitude Oscillatory Shear (SAOS). Native egg yolk containing 45 wt% solids was used for all the samples. Thermally set EY/κC gels were also studied by SAOS and texture analysis. A variety of linear viscoelastic behaviours depending on κC concentration and pH were exhibited by EY/κC dispersions that may be explained in terms of the contributions of electrostatic attractive interactions and an exclusion volume effect between protein and polysaccharide macromolecules. This last effect seems to be dominant as pH shifts towards the isoelectric point (IEP) of egg yolk proteins, whereas, at pH far from the IEP a certain enhancement in the degree of compatibility, and even some κC autohydrolysis, seems to take place. The results obtained either from rheological or textural characterization of gels were consistent with that balance. In any case, the results obtained suggest that the microstructure of gels is governed by the protein ability to form gels, where hydrophobically driven interactions and subsequent cross linking among protein segments play a dominant role.     

Sensor data analysis for equipment monitoring

Sensors play a key role in modern industrial plant operations. Nevertheless, the information they provide is still underused. Extracting information from the raw data generated by the sensors is a complicated task, and it is usually used to help the operator react to undesired events, other than preventing them. This paper presents SDAEM (Sensor Data Analysis for Equipment Monitoring), an oil process plant monitoring model that covers three main goals: mining the sensor time series data to understand plant operation status and predict failures, interpreting correlated data from different sensors to verify sensors interdependence, and adjusting equipments working set points that leads to a more stable plant operation and avoids an excessive number of alarms. In addition, as time series data generated by sensors grow at an extremely fast rate, SDAEM uses parallel processing to provide real-time feedback. We have applied our model to monitor a process plant of a Brazilian offshore platform. Initial results were promising since some undesired events were recognized and operators adopted the tool to assist them finding good set points for the oil processing equipments.     

Pd-decorated CNT as sensitive material for applications in hydrogen isotopes sensing - Application as gas sensor

Applicability of multiwall carbon nanotubes (MWCNTs) decorated with palladium nanoparticles as sensitive layer in a resistive microsensor for identification of hydrogen isotopes, Deuterium (²H) and Protium (¹H), has been demonstrated. Palladium nanoparticles were anchored on the MWCNTs surface via a chemical process involving micellization, from a precursor chloride solution, in high ultrasonic density field. Pd-MWCNTs are quasi-aligned between the interdigitated gold electrodes of a SiO₂ substrate by drop casting and di-electrophoretic alignment in Tetrahydrofuran (THF) and Nafion solution. The morphostructural characterization of the sensitive material has been carried out through SEM, TEM and Raman spectroscopy and its gas sensing properties were evaluated using electrical measurements performed on a series of isotope concentrations (ranging from 0.1% up to 1%, and from 1% to 4%, value to which hydrogen becomes explosive) diluted in argon, to observe the evolution of the sensor sensibility. The two hydrogen isotopes have different behaviors related to the adsorption on the Pd-MWCNT, which is well observed in the resistance change. Therefore, the sensor based on Pd-MWCNTs could be a viable solution to be integrated in systems for hydrogen leakage detection.     

Nanoparticles for intracellular-targeted drug delivery

Nanoparticles (NPs) are very promising for the intracellular delivery of anticancer and immunomodulatory drugs, stem cell differentiation biomolecules and cell activity modulators. Although initial studies in the area of intracellular drug delivery have been performed in the delivery of DNA, there is an increasing interest in the use of other molecules to modulate cell activity. Herein, we review the latest advances in the intracellular-targeted delivery of short interference RNA, proteins and small molecules using NPs. In most cases, the drugs act at different cellular organelles and therefore the drug-containing NPs should be directed to precise locations within the cell. This will lead to the desired magnitude and duration of the drug effects. The spatial control in the intracellular delivery might open new avenues to modulate cell activity while avoiding side-effects.