Predicting biomass combustion at temperatures of practical interest requires kinetic expression robust and reliable over a large temperature range. The present work examines experimental works on combustion kinetics of lignocellulosic biomass published since 2015 and reports the experimental methods used and the kinetic parameters obtained therein. The most common experimental strategy, used in 39 referenced works, was non-isothermal thermogravimetric analysis, yet the kinetic parameters obtained varied by order of magnitude. The large variability of the kinetic parameters found in literature cannot be only explained by the feedstock heterogeneity or the different data analysis methods. One possible and apparently neglected source of error lies in the fact lignocellulosic biomasses are complex materials, constituted by different components, thus thermogravimetric curves are the resultant of multiple and partly overlapping stages of mass loss. Kinetic analysis in this case easily generates errors. Another criticality that the work wants to emphasize is the fact that biomass pyrolyses, burns and even thermally anneals throughout a TGA experiment. These progressive structural changes are a further problem for application of conventional kinetic analysis methods. Altogether, it can be concluded that it is difficult to obtain from conventional TGA analysis reliable kinetic expressions of biomass combustion to be used for boilers modelling. For complex materials like biomass, it is recommended to adopt expert-case sensitive approaches. As an example, the case of walnut shells combustion is presented. For this material, four components with different combustion reactivity have been identified and simplified single rate kinetics are proposed according to the temperature interval of interest.

Quartz crystal microbalances are widely used sensors with applications for the detection of very-low-mass deposition in many different fields, from contamination monitoring in the high vacuum of deep space missions to the monitoring of biological activity or pollution using specifically designed active substrates. These sensors are very stable over time; nevertheless, their sensitivity to the temperature is well known, and different implementations have been devised to correct it, e.g., through compensation with a dual crystal. This paper deals with the effects of temperature on QCM but separates the case of uniform crystal temperature from the case of in-plane temperature gradients considering a QCM based on quartz crystals with deposited film resistors used as both RTDs and heaters. This configuration allows both an accurate temperature measurement and efficient thermal control, allowing the achievement of crystals temperatures in the order of 400 °C higher than the environment with a low power dissipation of the order of 1 W. The film resistors deposited around the electrodes allow directly measuring the average crystal temperature and directly delivering power to the crystal for thermal control. The localized delivery of the heat nevertheless also determines uncommon temperature fields on the crystal, and thus, an analysis of both the effects of temperature on the new microbalance was performed. The temperature gradient has strong effects on the frequency; therefore, along with the temperature, the thermal gradients have tobe compensated. The calibration of the QCM thermometers and the assessment of the achievable measurement accuracy were performed, as well as the determination of the frequency-temperature relationship. The comparison between frequency changes in the case of uniform temperature and those observed while using crystal heaters proved that temperature gradients have a strong effect on the crystal frequency. To identify the temperature field on the crystal surface of a QCM crystal, the gold coating of the deposited films was removed to achieve an emissivity acceptable for thermal imaging with an IR camera. Moreover, image processing for emissivity correction was developed. In order to correlate the temperature gradient with the frequency variation, a test campaign was performed to measure the frequency changes derived from different power levels delivered to the crystal heaters. From this test campaign and thermal analysis, the effect of the thermal gradient was assessed.

This work deals with temperature characterization of Cr-Au and Ti-Au deposited resistors on quartz crystal microbalances designed for Space. The advantage of the proposed configuration is that direct heating of the electrode's area can be obtained as well as a measurement of the quartz crystal temperature. In this view, characterization of the deposited materials is of primary importance to provide accurate temperature measurement and retrieve reliable results for thermogravimetric analyses. The behavior of the deposited material has been verified down to cryogenic temperatures. The characterization in cryogenic condition evidenced that the linearity error is limited to 4 °C at the liquid nitrogen temperature but the regression standard deviation can be reduced to one order of magnitude if a third-order polynomial is used to fit the experimental data.

This report describes the results of analyses carried out on paper cups claimed to be composed by "100% PAPER" to verify the presence of polyethylene (PE). The results are covered by Service Agreement (Prot. CNR-IPCB n° 624/2019 - 12/04/2019) and further extensions (Prot. CNR-IPCB n° 1399/2020 - 04/08/2020; Prot. CNR-IPCB n° 1921/2020 - 29/10/2020; Prot. CNR-IPCB n° 209/2021 - 02/02/2021) signed between CNR IPCB and Spere Distribution.

The development of sustainable building materials is essential in view of meting worldwide requirements of the green and sustainable economy; this aspect is crucial in cement concrete, in which commercial demand is increasing day by day. Superior quality concretes can be produced by using natural additives, such as biopolymers, being them harmfully respect to the environment. In this investigation, bio-additives prepared from cactus extract with varying concentrations was mixed into cement concrete mixtures for the manufacturing of sustainable concretes. The modified concretes were evaluated for their fresh and hardened state properties. The interaction of cactus extract with cement particles during hydration reactions was also examined by Fourier Transform Infrared Spectroscopy (FT-IR); the microstructural properties of the modified cement concrete was also studied through X-ray Diffraction (XRD) and Thermo Gravimetric Analysis (TGA). As a result, FT-IR evidenced that the additives containing polysaccharides enhanced the water retention of the concrete, preventing the early drying of the concrete mix and thereby reducing shrinkage cracks. Cactus extract enhances the viscosity property of the concrete mix and thereby improves the workability of the concrete mix. The results of the investigation also evidenced that modified concretes exhibit enhanced mechanical properties and durability characteristics. In particular, polysaccharides influence the strength characteristics of the additive modified concrete while proteins and fats have an impact on the workability and durability of modified concrete. Hence, the tested bio-additive could be considered as an eco-friendly, cheaper natural additive that could develop sustainable cement composites with upgraded workability, mechanical and durability characteristics.

Report sui risultati delle analisi effettuate per la trasmissione «Petrolio» - RAI 2 su posate e piatti dichiarati biodegradabili e compostabili e residui di film plastici da impianti di compostaggio. (Prot CNR-IPCB n° 0000483 del 27/02/2020)

The paper explores changes in reactivity and chemico-physical characteristics of char and tar produced by severe heat treatment of lignite in both inert atmospheres and CO2 rich atmospheres. The role of mineral matter, in particular metal oxides, in catalysing chemical and physical transformations is also addressed. A Rhenish Lignite from the Garzweiler mine was studied and compared with: a) mineral-free synthetic carbon (HTC), obtained from cellulose; b) a synthetic carbon doped with iron oxide (Fe2O3). A heated strip reactor (HSR) was employed at temperatures of 1300 and 1800 degrees C in N-2 and CO2 atmospheres. Liquid and solid products (tar and char) were analysed and compared. Tar composition was evaluated by extraction and gas chromatography-mass spectrometry, whereas the solid carbonaceous material produced by pyrolysis, mainly composed of char, was characterized regarding its thermal behaviour by thermogravimetric analysis and its structure by Raman spectroscopy and scanning electron microscopy. Results show that iron oxide exerts a catalytic influence on both pyrolysis and char oxidation. Upon severe heat treatment, it reduces char reactivity promoting graphitization and structural ordering. The overall effect on char reactivity is therefore not easy to predict.

In this work, the analysis of the potential and the issues of gasification of biomass produced from pruning from plant-assisted bioremediation (PABR) is presented. Such biomass contains a small but not negligible content in metals (mainly Cu and Zn) extracted from a contaminated soil. Even if most of the metals analysed are confined in the roots and then the risks of release of hazardous materials in the atmosphere is really very limited, we analyzed all the steps of the gasification process aiming at tracking the heavy metals, tars and other hazardous compounds to assess a safe procedure for trapping them. The biomass pruning, after preliminary TGA-DTA analysis, are used to produce syngas in the fluidized bed gasification plant located at Sapienza. The paper analyses the distribution and the composition of the solid particles and the volatile compounds released from the gasification process, allowing to determine that most of the metals are concentrated in the ashes while their content in the syngas is negligible.

This paper assesses the mechanical stability and dehydration behaviour of a new composite material constituted by magnesium sulphate hepta-hydrate, used as filler at vary contents, and a porous silicone, used as matrix in order to evaluate its applicability in sorption thermal energy storage field. This new composite was developed to avoid the typical issues of salt hydrates such as swelling, agglomeration and corrosion issues occurring during hydration/dehydration process. A preliminary physical-mechanical characterization, by means of morphological and calorimetric analysis, was carried out to investigate the main properties of the composite foams. The morphological characterization showed that the foam pores were homogenously distributed and well interconnected to each other. Thermo-gravimetric dehydration tests, have demonstrated that the tested samples are able to exchange efficiently water.

This paper reports about the first experimental activity on a composite material for thermal energy storage, based on a SrBr·6HO filled silicone foam. The morphological and thermal features of the composite with different salt content (i.e. between 40 wt.% and 70 wt.%) were investigated. The dehydration behavior was studied by thermo-gravimetric analysis. Furthermore, scanning electron and 3D optical microscopy were used to compare the cellular microstructure of the composite foams. The synthesized foams are characterized by a well-interconnected cellular structure with a three-dimensional porous network. This, together with the high permeability to water vapor of the matrix favors water vapor diffusion and allows the reaction of all the salt embedded in the matrix. The main advantages of the composite material were analyzed and compared to other composites in literature. Since the production process, especially for higher salt content, seemed not sufficiently effective, causing a reduced foaming ration and lower ability to incorporate the salt hydrate, possible improvements were proposed and discussed.

The present work describes the mechanical characterization combined with the thermal degradation kinetics of Carbon Fiber Reinforced Polymers (CFRP). The thermal degradation kinetics of CFRP have never been studied in the past. In that regard, the present work focuses on studying the thermal degradation kinetics of CFRP tested mechanically at different environmental conditions. Tensile tests were performed on the specimens with different lay-ups at room temperature, elevated temperature (71 °C), and cryogenic conditions (-54 °C), and the same specimens were used for thermal degradation kinetic studies. Mechanical tests show different responses respect to the different environmental conditions and different fibers orientation. On the other hand, the thermogravimetric results, mass loss, and derivative mass loss, show no significant difference in the degradation of CFRP tested at different temperatures. However, the thermal degradation kinetics shows more insight into the degradation pattern of the materials. The activation energy of degradation shows that the degradation of materials subjected to elevated conditions increases rapidly in the later stages of degradation, suggesting the formation of high char yield. The varying activation energy has been related to different degradation mechanisms. Lastly, the morphology of the materials was studied under SEM to understand the structural change in the material after tested in different weather conditions.

BACKGROUNDPea, lentil, faba bean, chickpea and bean proteins are potentially renewable raw materials for bioplastic production that can be obtained from agricultural waste. Plastics are usually processed under heating, and thus thermal stability is a mandatory requirement for the application. In this study, the thermal behavior of several legume protein isolates at different purity degrees was investigated.

This study deals with the development of new epoxy adhesive systems to be used in friction stir welding (FSW) technology and FSW-bonding hybrid technique for joining steel hull elements with aluminum superstructures. The addition of suitable additives, such as inorganic fillers, to the most promising formulations aims at obtaining materials not only leading to a stronger adhesion between the phases, but also characterized by improved thermal properties and good resistance to oxidation and chemical attacks. The polymeric adhesive systems here investigated were characterized by thermal analytical techniques, in particular focusing on kinetics of curing

The composition of the ancient wax-based painting technique known as encaustic has long been the subject of debate. Ancient sources provide few details of the technology, and modern understanding of the medium is restricted to theoretical interpretation and experimental observation. In this multi-analytical collaborative study, a number of analytical approaches were used to investigate the physical and molecular properties of a range of experimentally prepared encaustic paints before and after ageing. Analysis using gas chromatography mass spectrometry, Fourier transform infrared spectroscopy (invasive and non-invasive), X-ray diffraction and thermogravimetric analysis demonstrated how differences in the technology of production alter the properties and composition of the medium and showed how these are modified by the addition of pigment and the effects of ageing. Comparison of results from the different analytical techniques highlights the benefit of an integrated analytical approach to the analysis of ancient encaustic paints and the fundamental importance of insights from invasive study to evaluating the results of non-invasive analysis. (C) 2018 The Authors. Published by Elsevier B.V.

Activated carbon fabric (ACF) obtained from novolacs carbonization was used as substrate for N2O4 adsorption. In one case the ACF was soaked and impregnated with liquid N2O4 (ACF-liq-N2O4) reaching an adsorbate loading of about 1400 mg /g(ACF). Another ACF was prepared by adsorption of a gaseous stream of N2O4 (ACF-gas-N2O4). This time the adsorbate loading was found at 757 mg N2O4/g(ACF). The two samples were studied with FT-IR spectroscopy before and after the desorption. The amount of N2O4 in the ACF samples was determined gravimetrically, thermogravimetrically (TGA) and by wet chemical analysis after hydrolysis of the samples in water. The N(2)O(4)z/NO2 desorption from the ACF was studied by TGA-FTIR analytical technique and it was found that the NO2 desorption starts at low temperatures and reaches a peak at 158-170 degrees C. In the correspondence of the NO2 release peak starts also the gasification of the oxygenated groups present in the ACF with a simultaneous peak in the emission of CO2 and CO. From the DSC analysis of ACF-liq-N2O4 and ACF-gas-N2O4 the heat of adsorption of N2O4 was determined and found at -21.8 kcal/mol for ACF-liq-N2O4 and -16.2 kcal/mol for ACF-gas-N2O4. The electrical resistivity of the ACF before and after the N2O4 adsorption was measured.

La quantità di polietilene (PE) contenuta in miscele polimeriche è stata determinata tramite analisi termogravimetrica (TGA) e pirolisi-gas cromatografia/spettrometria di massa (Py-GC/MS). Per validare il metodo, sono state preparate blend a base di poli(butilenadipato-co-butilentereftalato) (PBAT), polilattide (PLA), amido nativo, CaCO3 e con percentuali variabili di PE (0 - 10%). La percentuale di PE determinata dalla perdita in peso alla TGA ha evidenziato una sovrastima di circa l'1.2 %, costante in tutte le blend, che è stata attribuita ad una parziale sovrapposizione di uno step degradativo del PBAT, i cui prodotti sono stati rilevati anche nei pirogrammi a 500 °C, insieme ai tripletti caratteristici del PE. La metodica è stata applicata inoltre a sacchi da asporto merci, dichiarati compostabili secondo la EN 13432, per alcuni dei quali è stato determinato un contenuto in PE superiore al limite consentito dalla normativa (1%).

Rapporto tecnico (Prot. CNR-IPCB N° 1543 del 20/05/2016) relativo alla determinazione di polietilene in manufatti dichiarati biodegradabili e compostabili, secondo metodica pubblicata in P. Rizzarelli et al. / Journal of Analytical and Applied Pyrolysis 117 (2016) 72-81, nell'ambito del Contratto di Prestazione di Servizi Stipulato con LEGAMBIENTE O.N.L.U.S., via Salaria 403, 01990 Roma (Prot. CNR-IPCB N° 0000577 del 26/02/2016)

Cement formulations based on reactive periclase (MgO) [1,2] constitute a promising emerging technology toward eco-sustainable binders, with reduced CO2 emissions as compared to the traditional CaO-based cements, which have been demonstrated useful in the field of radioactive waste containment. [3] The aim of the present study was the investigation of the hydration reaction and on the microstructure development of pastes prepared by mixing Portland cement and MgO/SiO2 blend. Different percentages of CaO- and MgO-based binders were evaluated to explore the possibility of preparing pastes that could in principle combine the optimal mechanical properties of calcium based cement with the ecological features of MgO-based cement. The hydration kinetics of the mixtures were investigated by means of Differential Scanning Calorimetry. Concurrently, the pastes were characterized by means of a multi-scale approach and the formation of hydrated phases was studied by Thermogravimetric Analysis, Fourier Transform IR spectroscopy and X-ray Diffraction. The structural properties of all samples were investigated by solid state 29Si-NMR. Finally, the morphology of the pastes has been studied by means of Scanning Electron Microscopy. The results showed that in the mixed pastes both calcium silicate hydrate (C-S-H) and M-S-H binder gel phases form, but, as evidenced in Fig.1, their domains remain segregate in different regions. Moreover, interestingly, the kinetics of hydration in the mixed samples is dominated by MgO/SiO2 hydration in the first period, while the diffusional stage is mostly dependent on the Portland cement presence. Acknowledgements: CSGI and FIR2013 (Project RBFR132WSM) for financial support. References [1] Lothenbach, B., et al., Magnesium and calcium silicate hydrates, Cement and Concrete Research, 2015. 77: p 60-68 [2] Chiang, W.-S., et al., Multiscale structure of calcium and magnesium silicate hydrate gels, Journal of Material Chemistry A, 2014. 2: p 12991-12998 [3] Walling, S. A.; et al. Structure and Properties of Binder Gels Formed in the System Mg(OH)2-SiO2-H2O for Immobilisation of Magnox Sludge. Dalton Trans. 2015, 44 (17), 8126- 8137.

La presente relazione riporta l'attività di caratterizzazione di un campione di C.S.S. ed ha riguardato la valutazione della qualità e della composizione chimica del campione ricevuto secondo quanto previsto dalla Norma UNI EN 15359.

Cement formulations based on reactive periclase (MgO) constitute one of the most promising emerging technologies for the reduction of CO2 emissions in the cement production.1 In the presence of water, MgO/silicate mixtures hydrate and form a binder phase, M-S-H (magnesium silicate hydrate), a colloidal gel analogue to calcium silicate hydrate, C-S-H, that is present in traditional cements. M-S-H based formulations have compressive strengths compatible with many potential applications2, but systematic studies defining the relationship among composition, structure and properties of these binders are still lacking. This knowledge is essential to optimize the properties of building materials, allowing a predictive approach of the final properties starting from the initial composition. In this work the hydration kinetics of MgO/silicate mixtures were investigated by means of differential scanning calorimetry. The most significant kinetic parameters (induction time, diffusion time, kinetic constants of nucleation and growth of hydrated phases) were accessed and correlated to the initial composition. Concurrently, pastes were characterized starting from the molecular level up to the micro/macroscopic scale. In particular SS NMR was used to probe the local Si environment and the polymerization degree of M-S-H; small angle x-ray scattering measurements were used to achieve information on the shape and size of the structural gel unit and on the fractality of the phase. Finally the composition and the morphology were characterized by combining XRD, FTIR, SEM/EDX measurements. 1.Vandeperre L.J. et al, Microstructures of reactive magnesia cement blends. Cem. Concr. Comp. 30, 706-714 (2008). 2.Zang T. et al., Development of low pH cement systems forming magnesium silicate hydrate (M-S-H). Cen. Concr. Res. 41, 439-442 (2011)