Thermal decomposition of the different particles size fractions of almond shells and olive stones. Thermal behaviour changes due to the milling processes

The aim of this study is to investigate the effect of particle size on the non-isothermal pyrolysis of almond shells (AS) and olive stones (OS) and to show possible differences in the composition of the different fractions obtained after milling and sieving. The results obtained from the study of different particle size of AS and OS samples show significant differences in the solid residue obtained and in the shape and overlapping degree of the peaks, especially with the smaller particle size. These differences can be due to different factors: (a) the amount of inorganic matter, which increases as particle size decreases, (b) heat and mass transfer processes, (c) different sample composition as a consequence of the milling process which may provoke changes in the structure and the segregation of the components (in addition to the ashes) increasingly changes the composition of the sample as the particle size decreases.

Well-defined mesoporosity on lignocellulosic-derived activated carbons

Activated carbons with a highly developed mesoscale cavitation-linked structure have been prepared from natural products (e.g. peach stones) by combining chemical and physical activation processes. Characterization results show that these materials exhibit a large “apparent” surface area (∼1500 m2/g) together with a well-defined mesoporous structure, i.e. large cavities connected to the external surface through narrower mesoporous necks (cavitation effects).

Assessment of CO2 adsorption capacity on activated carbons by a combination of batch and dynamic tests

In this work, batch and dynamic adsorption tests are coupled for an accurate evaluation of CO2 adsorption performance for three different activated carbons obtained from olives stones by chemical activation followed by physical activation with CO2 at varying times, i.e. 20, 40 and 60 h. Kinetic and thermodynamic CO2 adsorption tests from simulated flue-gas at different temperature and CO2 pressure are carried out both in batch (a manometric equipment operating with pure CO2) and dynamic (a lab-scale fixed-bed column operating with CO2/N2 mixture) conditions. The textural characterization of the activated carbon samples shows a direct dependence of both micropore and ultramicropore volume on the activation time, hence AC60 has the higher contribution. The adsorption tests conducted at 273 and 293 K showed that, when CO2 pressure is lower than 0.3 bar, the lower the activation time the higher CO2 adsorption capacity and a ranking ωeq(AC20)>ωeq(AC40)>ωeq(AC60) can be exactly defined when T= 293 K. This result can be likely ascribed to a narrower pore size distribution of the AC20 sample, whose smaller pores are more effective for CO2 capture at higher temperature and lower CO2 pressure, the latter representing operating conditions of major interest for decarbonation of a flue-gas effluent. Moreover, the experimental results obtained from dynamic tests confirm the results derived from the batch tests in terms of CO2 adsorption capacity. It is important to highlight that the adsorption of N2 on the synthesized AC samples can be considered negligible. Finally, the importance of a proper analysis of characterization data and adsorption experimental results is highlighted for a correct assessment of CO2 removal performances of activated carbons at different CO2 pressure and operating temperature.

Non-porous reference carbon for N2 (77.4 K) and Ar (87.3 K) adsorption

A new non-porous carbon material from granular olive stones has been prepared to be used as a reference material for the characterization of the pore structure of activated carbons. The high precision adsorption isotherms of nitrogen at 77.4 K and argon at 87.3 K on the newly developed sample have been measured, providing the standard data for a more accurate comparative analysis to characterize disordered porous carbons using comparative methods such as t- and αS-methods.

Optimal model through identified frequencies of a masonry building structure with wooden floors

The paper presents the analysis of an important historical building: the Saint James Theater in the city of Corfù (Greece) actually used as the Municipality House. The building, located in the center of the city, is made of carves stones and is characterized by a stocky shape and by the presence of wooden floors. The study deals with the structural identification of such structure through the analysis of its ambient vibrations recorded by means of accelerometers with high accuracy. A full dynamic testing was developed using ambient vibrations to identify the main modal parameters and to make a non-destructive characterization of this building. The results of these dynamic tests are compared with the modal analysis of a complex finite element (FE) simulation of the structure. This analysis may present several problems and uncertainties for this stocky building. Due to the presence of wooden floors, the local modes can be highly excited and, as a consequence, the evaluation of the structural modal parameters presents some difficulties.

Switchable surfactant-assisted carbon nanotube coatings: innovation through pH shift

The inner surface of fused-silica capillaries has been coated with a dense/homogeneous coating of commercial multi-wall carbon nanotubes (MWCNTs) using a stable ink as deposit precursor. Solubilization of the MWCNTs was achieved in water/ethanol/dimethylformamide by the action of a surfactant, which can switch between a neutral or an ionic form depending on the pH of the medium, which thus becomes the driving force for the entire deposition process. Careful control of the experimental conditions has allowed us to selectively deposit CNTs on the inner surface of insulating silica capillaries by a simple, reproducible, and easily adaptable method.

Geological risk assessment of Amtoudi Agadir in southern Morocco: a key case for sustainable cultural heritage

Medieval fortified granaries known as “agadirs” are very common in southern Morocco, being catalogued as world cultural heritage by United Nations. These Berber buildings (made of stones and tree trunks) usually located on rocky promontories, constitute historical testimonials related to the origin of Morocco, and, as tourist attractions, have a positive impact on the local economy. The sustainability of these ancient monuments requires geological-risk evaluations of the massif stability under the agadir with the proposal of stabilization measures, and an architectonic analysis with appropriate maintenance of the structural elements. An interdisciplinary study including climate, seismicity, hydrology, geology, geomorphology, geotechnical surveys of the massif, and diagnosis of the degradation of structural elements have been performed on the Amtoudi Agadir, selected as a case study. The main findings from this study are that the prevalent rocks used for construction (coming from the underlying substratum) are good-quality arkosic sandstones; the SW cliffs under the agadir are unstable under water saturation; some masonry walls are too thin and lack interlocking stones and mortar; and failures in the beams (due to flexure, fracture, and exhaustion in the resistance due to insect attacks or plant roots) are common. The basic risk assessment of ancient buildings of cultural heritage and their geologic substratum are needed especially in undeveloped areas with limited capacity to implement durable conservation policies. Therefore, recommendations have been provided to ensure the stability and maintenance of this important archaeological site.

Los mármoles comerciales “Marrón Imperial” y “Marrón Emperador” (S.E. España). Caracterización petrológica y criterios de exploración

Los mármoles comerciales "Marrón Imperial" y "Marrón Emperador" son dolomías brechoides que de acuerdo con la clasificación del MIA pertenece al Grupo C de mármoles comerciales. Se determinan sus parámetros petrofísicos según la norma UNE. Sus rasgos petrológicos se estudian mediante microscopio petrográfico de luz transmitida y microscopio electrónico de barrido (MEB) (en modo de electrones secundarios y electrones retrodispersados). Estas rocas son básicamente dolomías mesocristalinas con abundantes vénulas calcíticas politexturales relacionadas con procesos de brechificación y de dolomitización. Rasgos kársticos aumentan la complejidad petrológica de estas rocas ornamentales cuyo litosoma son las dolomías masivas del Cretácico Superior (¿Turoniense?) del dominio Prebético Externo. El material explotado pertenece a una alineación morfoestructural que va desde Jumilla hasta el NE de Caudete y está relacionado con la falla Jumilla-Yecla-Caudete-Font de la Figuera. La relación entre esta falla y las dolomías turonienses son el principal criterio de exploración de estas rocas ornamentales.

Performance Assessment of a Polymer Electrolyte Membrane Electrochemical Reactor under Alkaline Conditions – A Case Study with the Electrooxidation of Alcohols

A novel polymer electrolyte membrane electrochemical reactor (PEMER) configuration has been employed for the direct electrooxidation of propargyl alcohol (PGA), a model primary alcohol, towards its carboxylic acid derivatives in alkaline medium. The PEMER configuration comprised of an anode and cathode based on nanoparticulate Ni and Pt electrocatalysts, respectively, supported on carbonaceous substrates. The electrooxidation of PGA was performed in 1.0 M NaOH, where a cathode based on a gas diffusion electrode was manufactured for the reduction of oxygen in alkaline conditions. The performance of a novel alkaline anion-exchange membrane based on Chitosan (CS) and Poly(vinyl) alcohol (PVA) in a 50:50 composition ratio doped with a 5 wt.% of poly (4-vinylpyridine) organic ionomer cross-linked, methyl chloride quaternary salt resin (4VP) was assessed as solid polymer electrolyte. The influence of 4VP anionic ionomer loading of 7, 12 and 20 wt.% incorporated into the electrocatalytic layers was examined by SEM and cyclic voltammetry (CV) upon the optimisation of the electroactive area, the mechanical stability and cohesion of the catalytic ink onto the carbonaceous substrate for both electrodes. The performance of the 4VP/CS:PVA membrane was compared with the commercial alkaline anion-exchange membrane FAA −a membrane generally used in direct alcohol alkaline fuel cells- in terms of polarisation plots in alkaline conditions. Furthermore, preparative electrolyses of the electrooxidation of PGA was performed under alkaline conditions of 1 M NaOH at constant current density of 20 mA cm−2 using a PEMER configuration to provide proof of the principle of the feasibility of the electrooxidation of other alcohols in alkaline media. PGA conversion to Z isomers of 3-(2-propynoxy)-2-propenoic acid (Z-PPA) was circa 0.77, with average current efficiency of 0.32. Alkaline stability of the membranes within the PEMER configuration was finally evaluated after the electrooxidation of PGA.

Colour changes by laser irradiation of reddish building limestones

We have used X-ray photoelectron spectroscopy (XPS) as a novel method to investigate the causes of colour changes in a reddish limestone under irradiation by a Q-switched Nd:YAG 1064 nm laser. We irradiated clean dry and wet surfaces of Pidramuelle Roja, a building stone frequently used in the Asturian heritage, at fluences ranging from 0.12 to 1.47 J cm−2. We measured the colour coordinates and undertook XPS analysis of the state of oxidation of iron both before and after irradiation. Visible colour changes and potential aesthetic damage occurred on dry surfaces from a fluence of 0.31 J cm−2, with the stone showing a greening effect and very intense darkening. The colour change on dry surfaces was considerably higher than on wet surfaces, which at the highest fluence (1.47 J cm−2) was also above the human visual detection threshold. The use of XPS demonstrated that the change in colour (chroma and hue) is associated with a reduction in the iron oxidation state on dry surfaces during laser irradiation. This points out to a potential routinary use of XPS to analyse causes of colour changes during laser cleaning in other types of coloured building stones.

New York, April 1990: A Photographic Record

Aquestes fotografies de Nova York i de Boston, totes en blanc i negre, es van fer en abril del 1990, amb una cambra rèflex Asahi Pentax Spotmatic II amb objectiu de 50 mm, tot fent servir negatius Kodak Safety Film 5063. El Museu de la Universitat d’Alacant en conserva una col·lecció completa; vuitanta-set còpies fotogràfiques de 32 x 24 cm amb tintes Ultrachrome sobre paper Ilford Gold Fibre Silk de 310 gr/m² realitzades al “Estudio Paco Mora” de València l’any 2015, amb digitalització prèvia a partir dels negatius originals mitjançant un escàner Haselblad Flextight X 1 a una resolució de 3.200 punts per polzada.

Souvenir de Paris, novembre 1973

Aquestes fotografies de París, totes en color, es van fer en novembre del 1973 amb una cambra rèflex Asahi Pentax Spotmatic II amb objectiu de 50 mm, tot fent servir diapositives Orwo, Kodak i Agfa. El Museu de la Universitat d’Alacant en conserva una col·lecció completa; 147 còpies fotogràfiques de 32 x 24 cm amb tintes Ultrachrome sobre paper Ilford Gold Fibre Silk de 310 gr/m² realitzades al “Estudio Paco Mora” de València l’any 2015, amb digitalització prèvia a partir de les diapositives originals mitjançant un escàner Haselblad Flextight X 1 a una resolució de 3.200 punts per polzada.