964 research outputs found

    Thermally induced behavior of the K-exchanged erionite. A further step in understanding the structural modifications of the erionite group upon heating

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    Fibrous erionite is a naturally occurring zeolite considered to be highly carcinogenic upon inhalation, even more than crocidolite. Since no iron is typically present in erionite, its toxicity has been attributed to ion-exchanged Fe participating in Fenton chemistry. Recently, a study aimed at investigating possible fiber inactivation routes surprisingly showed that, despite having completely occluded all available pores with K ions, the erionite-Na sample preserved the property to upload Fe (II) within the structure. In this work, the thermal behavior of the K-exchanged erionite-Na was investigated by TG/ DSC and in situ XRPD analyses in order to provide relevant information for modeling the thermally induced behavior of the erionite group. Rietveld refinement results evidenced a general trend of cell parameters and volume with temperature similar to that observed for erionite-K from Rome (Oregon, USA). However, the dependence of Tdehydrand Tbreakfrom Si/Si+Al ratio observed in zeolites (high Si content favours a lower Tdehydrand a higher Tbreak) is not observed, possibly due to the effect of the relevant amount of large K ions dispersed within the erionite cage, acting as reinforcing blocks for the framework. Heating produces a progressive emptying of the Ca sites, common effect previously observed in erionite samples showing different chemistry. In addition, K1 s.s. remains unchanged evidencing the absence of any “internal ion exchange” process, whereas s.s. at K2 increases in the range 438-573 K and then slowly decreases in the range 700-1218 K. Both Rietveld and DSC data suggest the motion of K ions from OW sites toward the walls of the erionite cavity during dehydration

    Kaon physics with the KLOE detector

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    In this paper we discuss the recent finalized analyses by the KLOE experiment at DAΦ\PhiNE: the CPT and Lorentz invariance test with entangled K0Kˉ0K^0 \bar{K}^0 pairs, and the precision measurement of the branching fraction of the decay K+π+ππ+(γ){ K^+} \rightarrow \pi^+\pi^-\pi^+(\gamma). We also present the status of an ongoing analysis aiming to precisely measure the K±K^{\pm} mass

    Primary cosmic ray spectrum in the 10 to the 12th power - 10 to the 16th power eV energy range from the NUSEX experiment

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    A primary cosmic ray spectrum was derived which fits both experimental multiple muon rates and the all-nucleon flux derived from the single muon intensities underground. In the frame of the interaction model developed by Gaisser, Elbert and Stanev, it is possible to reproduce NUSEX muon data with a primary composition in which the iron spectrum is only slightly flatter than the proton one. This result rules out the popular idea that the primary composition varies drastically with increasing energy, leading to the dominance of heavier nuclei at energies 10 to the 15th power to 10 to the 16th power eV

    Experimental and theoretical evaluations on Oleuropein as a natural origin corrosion inhibitor for copper in acidic environment

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    none5siCopper corrosion in acidic cleaning solutions is a major worry for heat exchangers. Corrosion inhibitors derived from natural sources might be a viable option. The isolation of Oleuropein compound from olive leaf and investigation of its anticorrosion potential for copper in 1.0 M H2SO4 solution are reported here. All experimental results from LC-MS, FT-IR, 1H and 13C-NMR characterizations support the molecular structure of Oleuropein. Electrochemical and gravimetric tests were used to evaluate the corrosion inhibition capabilities of Oleuropein. According to polarization investigation, Oleuropein is a mixed-type inhibitor. Oleuropein's inhibitory efficacy increases with concentration, attaining an optimum value (98.92%) at 100 mg L-1. At high temperatures, Oleuropein can be considered an efficient inhibitor. Thermodynamic variables for the activation operation and copper dissolution were computed and addressed as well. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examinations revealed that Oleuropein produced an outer layer on the copper surface, shielding it from severe acid damage. Quantum chemical simulations were employed to propose molecular explanations for Oleuropein's inhibitory actions.Deyab, M A; Mohsen, Q; Bloise, E; Lazzoi, M R; Mele, GDeyab, M A; Mohsen, Q; Bloise, E; Lazzoi, M R; Mele,

    Advances in Nanomaterials Based on Cashew Nut Shell Liquid

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    Cashew nut shell liquid (CNSL), obtained as a byproduct of the cashew industry, represents an important natural source of phenolic compounds, with important environmental benefits due to the large availability and low cost of the unique renewable starting material, that can be used as an alternative to synthetic substances in many industrial applications. The peculiarity of the functional groups of CNSL components, such as phenolic hydroxyl, the aromatic ring, acid functionality, and unsaturation(s) in the C15 alkyl side chain, permitted the design of interesting nanostructures. Cardanol (CA), anacardic acid (AA), and cardol (CD), opportunely isolated from CNSL, served as building blocks for generating an amazing class of nanomaterials with chemical, physical, and morphological properties that can be tuned in view of their applications, particularly focused on their bioactive properties

    Environmentally Friendly Method of Assembly of Cardanol and Cholesterol into Nanostructures Using a Continuous Flow Microfluidic Device

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    This study shows a viable and straightforward microfluidic method of assembly of cardanol (CA) and cholesterol (CH) into amphiphile nanostructures obtained through a hydrodynamic focusing approach according to which an alcoholic solution of CA and CH is constrained within a two-dimensional lamina shape by two lateral streams of borate buffer solution. The process is performed within glass-made cross-shaped micro-sized fluidic chips specially designed to achieve a laminar regime. CA, distilled from the cashew nut shell liquid, is demonstrated as a surface-active molecule in borate buffer basic medium and when mixed with CH it produces versatile nanovesicles through an in-batch solvent-free process. Compared to this conventional method, the microfluidic route allows operating under continuous flows, with a reduced amount of reagents and at lower experimental temperatures, ensuring no waste formation and the achievement of size-monodisperse amphiphile nanostructures that do not need further steps of purification. Electron microscopy analyses demonstrate that upon increasing CH in the lipid mixture, a switchover from spherical CA micelles to CA/CH mixed closed vesicles occurs. Differential scanning microcalorimetry confirms the formation of vesicular structures and evidences the primary role of CH, which increasingly lowers the temperature of transition depending on its concentration

    Bio-based benzoxazines synthesized in a deep eutectic solvent: A greener approach toward vesicular nanosystems

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    A green synthesis of benzoxazines, based upon reaction of cardanol with formaldehyde and primary amines, is achieved in high yields using choline chloride-urea mixture as deep eutectic solvent. Then, it is demonstrated how the cardanol-based benxoxazines can be employed as only component for the preparation of a nanovesicular systems
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