Sodium Doped LaMnO3 Thin Films: Influence of Substrate and Thickness on Physical Properties

In this paper we report the results about the synthesis and characterization of optimally doped La1-xNaxMnO3 thin films grown onto SrTiO3 (100), NdGaO3 (100) and NdGaO3 (110) for thickness ranging from 11 to 82 nm. The effect of substrate nature and orientation, film thickness and annealing procedure was investigated in order to optimize their magnetoresistance (MR). We obtained very smooth films displaying MR values greater than 70%, near to room temperature.Comment: 31 pages, 9 figures Final version to appear in J. Phys. Chem.

Chemical Analysis of Air Particulate Matter Trapped by a Porous Material, Synthesized from Silica Fume and Sodium Alginate

This work shows the ability of a new porous material (SUNSPACE), obtained by industrial by-products, to sequestrate air particulate matter (PM). This activity allows introducing the azure chemistry approach, devoted to better link new remediation strategies and sustainability. In particular, SUNSPACE is synthesized from silica fume and sodium alginate; it can be shaped in a porous solid, and it looks promising for environmental application as nanoparticle sequestration. Studies to evaluate the sequestration capability of SUNSPACE are performed in different environments, with and without anthropogenic sources of PM. Solid SUNSPACE disc samples are used as passive samplers and exposed for one and two months, in vertical and horizontal positions, indoor, and outdoor. Total reflection X-ray fluorescence technique is employed to perform elemental chemical analysis of the entrapped PM. Two sample preparation strategies to evaluate the composition of PM are considered: sample sonication in Milli-Q water and total sample mineralization by microwave acid digestion. These two options are proposed to analyse different PM fractions: in particular, sonication allows removing the coarse PM, entrapped on external material surface pores; on the contrary, digestion can offer information on fine and ultrafine PM, trapped in internal pores. Results confirm the ability of the porous material to sequestrate air PM and the differences in the sample preparation, supported by elemental analysis, and show the difference in the coarse and fine air particulate matter composition. In summary, the new material results as very promising for applications requiring nanoparticle sequestration

Environmental Impact of Surgical Masks Consumption in Italy Due to COVID-19 Pandemic

The COVID-19 pandemic suddenly changed the lifestyle of billions of people. Face masks became indispensable to protect from the contagion providing a significant environmental impact. The aim of this work is to propose possible solutions to decrease masks’ impact on the environment. For this reason, different masks (surgical and fabric) were considered, and the CO2 emissions associated with the mask materials production were calculated. Carbon Footprint (CF) for each material composing the masks was evaluated through the database Ces Selector 2019. The software Qgis (version 2.18.20) allows us to elaborate the CO2 emissions maps for each Italian region. Finally, for surgical masks, which are often imported from abroad, the CF related to transport was considered. It results that fabric masks are a sustainable solution to prevent contagion. The total CO2 emission associated with the use of fabric masks from the beginning of the pandemic (March 2020) to December 2021 resulted in about 7 kton compared to 350 kton for surgical masks

Assessment of the influence of electric arc furnace slag as a non-conventional filler for Nitrile Butadiene Rubber

Reinforcement of polymers by the addition of particles filler is a complex phenomenon that depends mainly on the hydrodynamic effect and a complex interplay between polymer, filler, and interfacial region. Mineral fillers are usually adopted as low-cost extenders due to their lower cost. In this study, the influence of a waste material such as electric arc furnace steel slag is assessed as filler for Nitrile-Butadiene Rubber following experimental procedures and analytical calculations adopted for traditional fillers. It was found that the slag content affects the static and the dynamic properties by increasing the material's capability to storage and dissipate energy. In addition to an important contribution of the hydrodynamic effect, the presence of an increasing immobilized rubber fraction around the slag particles (quantified by a differential scanning calorimetry analysis) plays a central role. The slag stiffens the NBR composite; the increase of static tensile and dynamic shear storage moduli was found to be consistent with the Halpin-Tsai and Guth-Gold prevision models respectively. Moreover, the non-linear dynamic behavior was found to be well-fitted by the Kraus equation models. The reinforcing ability of the slag particles as filler was confirmed by the negative slope of the Kraus plot on swelling data

Application of benchtop total-reflection X-ray fluorescence spectrometry and chemometrics in classification of origin and type of Croatian wines

The contents of selected metals (K, Ca, Fe, Cu, Zn, Mn, Sr, Rb, Ba, Pb, Ni, Cr and V) in 70 wine samples from Continental and Adriatic part of Croatia and different types of wine (red and white) were determined by TXRF. The aim of this study was to compare the elemental composition of wines from two different regions and to determine the discriminant ability of each variable and to indicate which variables discriminate between the four categories considered. Principal component analysis and cluster analysis showed that K, Mn, Ba and Ni can be considered as the most important characteristics to distinguish between Continental red and white wines, Rb, Ni and Ba for Continental red and Adriatic red wines while Sr is the only metal that completely distinguishes the samples of each category. Finally, linear discriminant analysis showed good recognition (100%) and prediction abilities (96.43%) using these selected elements

Utilization of Third-Stage Waste from a Rice Production for Removal of H2S, NO2 and SO2 from Air:

Materials derived from rice husk fly ash were tested as adsorbents of hydrogen sulphide, sulphur dioxide and nitrogen dioxide. Breakthrough experiments were carried out at ambient temperature either in dry or moist air. The second-stage waste obtained in the extraction of silica from fly ash using sodium hydroxide exhibits the better adsorption capacity compared with that of caustic-modified activated carbons. The high performance is related to the presence of residual sodium hydroxide and other metals such as calcium, which react with acidic gases forming corresponding salts. Moreover, a high dispersion of the alkali and alkaline earth metal sites in the mesopores renders the pH of the solution basic, aiding in the dissociation of hydrogen sulphide, thereby facilitating its oxidation. The oxidation of species is also catalyzed by the carbonaceous surface. While in the case of hydrogen sulphide and sulphur dioxide, water helps in acid-base reactions, the opposite effect is found for NO2. Because its react..

waste silica sources as heavy metal stabilizers for municipal solid waste incineration fly ash

Abstract The present work discusses a new method, based on the use of silica fume, for heavy metal stabilization. The inertization procedure is reported and compared with other technologies, involving the employ of amorphous silica as stabilizing agent for municipal solid waste incinerator fly ash treatment (i.e. colloidal silica and rice husk ash). The obtained final materials are characterized in terms of chemical composition and phase analysis. The reported method, realized at room temperature, employs all waste or by-product materials. As a consequence it appears to be economically and environmentally sustainable

Growth and microstructural analysis of nanosized Y2O3 doped with rare-earths

Nanosized cubic Y2O3 samples, undoped and doped with 10 mol% Nd2O3, Eu2O3, Gd2O3, Tb2O3, Ho2O3 and Er2O3 (Y(1.8)Ln(0.2)O(3), where Ln=Nd, Eu, Gd, Tb, Ho or Er), were prepared by means of a controlled hydrolysis method in an aqueous solution containing ammonia, Y(NO3)(3) and Ln(NO3)(3) as precursors, and a surface modifier. The microstrain and the average size of the diffraction domains have been calculated from the XRD patterns and the results have been compared with those obtained by a combustion synthesis. It is shown that the cell parameter of the C-M2O3 (bcc structure related to the CaF2 structure; the M atom is 6-coordinated) structure of doped Y2O3 is correlated to the ion size of the dopant. The shape of the crystallites appears to be needle-like in all cases, while the microstrains depend on the dopant and are probably due to surface effect. XRD and Raman analysis show that, despite the heavy doping, only one phase in the Y2O3 powders is present. (C) 2000 Elsevier Science S.A. All rights reserved

Nanoliter contact angle probes tumor angiogenic ligand-receptor protein interactions

Any molecular recognition reaction supported by a solid-phase drives a specific change of the solid-solution interfacial tension. Sessile Contact Angle (CA) experiments can be readily used to track this thermodynamic parameter, prompting this well-known technique to be reinvented as an alternative, easy-access and label-free way to probe and study molecular recognition events. Here we deploy this technique, renamed for this application CONAMORE (CONtact Angle MOlecular REcognition), to study the interaction of the tumor-derived pro-angiogenic vascular endothelial growth factor-A (VEGF-A) with the extracellular domain of its receptor VEGFR2. We show that CONAMORE recognizes the high affinity binding of VEGF-A at nanomolar concentrations to surface-immobilized VEGFR2 regardless of the presence of a ten folds excess of a non specific interacting protein, and that it further proofs its specificity and reliability on competitive binding experiments involving neutralizing anti-VEGF-A antibodies. Finally, CONAMORE shows the outstanding capability to detect the specific interaction between VEGFR2 and low molecular weight ligands, such as Cyclo-VEGI, a VEGFR2 antagonist cyclo-peptide, that weights about 2 kDa