To improve the mechanical strength of sealants for solid oxide fuel cell (SOFC) stacks, several fillers were proposed in this work as reinforcement for a glass-ceramic sealant based on the system BaO-CaO-SiO2. The chosen reinforcement additives were metallic particles including nickel, a nickel-chromium alloy and silver, as well as ceramics such as gadolinium-doped ceria particles and yttrium-stabilized zirconia particles or fibers. The glass-ceramic sealant, with and without reinforcements, was used to join two parts made of stainless steel (Crofer22APU). A torsion test was used to measure the shear strength of the joined samples. The shear strength measurement by torsion gave reliable and reproducible results for all the joined samples. The lowest shear strength was found for the glass-ceramic sealant without any reinforcement. The composite prepared of a combination of glass matrix and 20 wt.-% Ni powder seems to be the best candidate sealant, able to fulfill all the requirements of a SOFC sealant. The samples made with this composite sealant presented the highest shear strength values as prepared and also after aging the sample in air atmosphere for 500 hours at 800 degrees C.

Lentil samples coming from two different countries, i.e. Italy and Canada, were analysed using untargeted 1H NMR fingerprinting in combination with chemometrics in order to build models able to classify them according to their geographical origin. For such aim, Soft Independent Modelling of Class Analogy (SIMCA), k-Nearest Neighbor (k-NN), Principal Component Analysis followed by Linear Discriminant Analysis (PCA-LDA) and Partial Least Squares-Discriminant Analysis (PLS-DA) were applied to the NMR data and the results were compared. The best combination of average recognition (100%) and cross-validation prediction abilities (96.7%) was obtained for the PCA-LDA. All the statistical models were validated both by using a test set and by carrying out a Monte Carlo Cross Validation: the obtained performances were found to be satisfying for all the models, with prediction abilities higher than 95% demonstrating the suitability of the developed methods. Finally, the metabolites that mostly contributed to the lentil discrimination were indicated.

The international fusion community has designed a miniature torsion specimen for neutron irradiation studies of joined SiC and SiC/SiC composite materials. Miniature torsion joints based on this specimen design were fabricated using displacement reactions between Si and TiC to produce Ti3SiC2 + SiC joints with SiC and tested in torsion-shear prior to and after neutron irradiation. However, many miniature torsion specimens fail out-of-plane within the SiC specimen body, which makes it problematic to assign a shear strength value to the joints and makes it difficult to compare unirradiated and irradiated strengths to determine irradiation effects. Finite element elastic damage and elastic-plastic damage models of miniature torsion joints are developed that indicate shear fracture is more likely to occur within the body of the joined sample and cause out-of-plane failures for miniature torsion specimens when a certain modulus and strength ratio between the joint material and the joined material exists. The model results are compared and discussed with regard to unirradiated and irradiated test data for a variety of joint materials. The unirradiated data includes Ti3SiC2 + SiC/CVD-SiC joints with tailored joint moduli, and includes steel/epoxy and CVD-SiC/epoxy joints. The implications for joint data based on this sample design are discussed. (C) 2015 Elsevier B.V. All rights reserved.

The photoreactivity of 4-thiothymidine (S(4)TdR) under visible light in the presence of Rose Bengal (RB), acting as a photosensitizer, was investigated in aqueous solutions at pH 7 and 12, using UV-vis, FTIR-ATR and (1)H-NMR spectroscopic techniques, time resolved absorption spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Evidence for the generation of thymidine (TdR) as the main product, after one hour of irradiation, was obtained from UV-Vis data, that suggested 4-thiothymidine photodegradation to be faster at basic pH, and confirmed by FTIR-ATR and (1)H-NMR data. Clues for the presence of a further product, likely corresponding to a dimeric form of S(4)TdR, were obtained from the latter techniques. Besides indicating the presence of thymidine, the ESI-MS and MS/MS spectra of the reaction mixtures enabled the identification of the additional product as a S-S bridged covalent dimer of 4-thiothymidine. The concentration of the dimeric species could be estimated with the aid of (1)H-NMR data and was found to be lower than that of thymidine in pH 7 reaction mixtures and almost negligible in the pH 12 ones. From a mechanistic point of view, time-resolved absorption spectroscopy measurements provided direct evidence that the formation of the two products cannot be ascribed to a photoinduced electron transfer involving S(4)TdR and the excited triplet state of RB. Rather, their generation can be interpreted as the result of a bimolecular reaction occurring between singlet state oxygen ((1)O2), photogenerated by RB, and S(4)TdR, as demonstrated by the direct detection of (1)O2 through IR luminescence spectroscopy. More specifically, a sequential reaction pathway, consisting in the generation of an electrophilic hydroxylated form of S(4)TdR and its subsequent, rapid reaction with S(4)TdR, was hypothesized to explain the presence of the S-S bridged covalent dimer of 4-thiothymidine in the reaction mixtures. The described processes make S(4)TdR an interesting candidate in the role of molecular probe for the detection of (1)O2 under different pH conditions.

A wine was obtained from cryomacerated Minutolo grapes under reductive conditions and aged for 12months in glass container and in 3 types of amphorae. After aging, wines in glass containers showed the highest alcohol content, volatile acidity, dissolved oxygen, concentrations of aromatics, alcohols, and esters and by the lowest contents of enols and terpenes. They also showed the highest decrease of flavonoids, hydroxycinnamoyl tartaric acids, and procyanidins. Wines in raw amphorae showed the dramatic decrease of flavonoids and flavans reactive with vanillin. The highest antioxidant activity was exhibited by wines in engobe amphorae, while the lowest values were showed by the wines in glass containers and glazed amphorae. Caftaric acid and procyanidin B3 decreased in wine aged under glass while epicatechin mainly reduced in raw amphorae. According to the Principal Component Analysis, the wines resulted homogeneously grouped as a function of the type of container in which were aged.

Different approaches are used for the integration of ceramic components in solid oxide fuel cells stacks, where dissimilar materials (ceramics and metals) have to be joined and coupled for a reliable long term operation. This work focuses on the mechanical characterisation of a glass ceramic sealant used for the joining of Crofer22APU metallic interconnect samples as well as the interaction with a preoxidised Crofer22APU. Crofer22APU–glass ceramic sealant joined samples are tested by two different mechanical tests. Hourglass samples with different geometries were tested using an in-house developed torsion test machine at room temperature. In addition, their mechanical strength was also evaluated according to the ISO 13124 standard. The comparison of the two different testing methods, with particular focus on the shear strength of the joined samples, are reviewed and discussed.

In recent years, food authentication, in terms of geographical and varietal/animal origins, is considered of primary importance at all levels of the production process. Therefore, it is clear that there is an economic basis to develop analytical methods able to certify the declared origin of food products, in order to protect consumers and honest producers from fraud and unfair competition, respectively; consequently, during recent years, several food authentication techniques have been proposed. This review attempted to present in a critical way the contribution of High Resolution Nuclear Magnetic Resonance (HR-NMR) and Isotope Ratio Mass Spectrometry (IRMS) techniques in the assessment of quality and authenticity, mainly in terms of characterization of geographical and varietal origin, of wheat and wheat products, focusing on the most important studies to this direction.

The interaction of ochratoxin A (OTA) with heptakis-2,6-di-O-methyl-β-cyclodextrin (DIMEB) in aqueous solutions at two different pHs (3.5 and 9.5) was studied by means of spectroscopic, calorimetric and electrochemical techniques. DIMEB affected the physico-chemical properties of OTA. A stronger interaction was observed at pH = 3.5 where the neutral form of OTA prevails. The spectroscopic information indicated that the OTA/DIMEB inclusion process occurred through the insertion of the phenylalanine group into the cyclodextrin (CD) cavity; moreover, voltammetry experiments showed that the isocoumarinic phenolic group was also involved, probably by non-inclusion interactions. At pH = 3.5, binding constants and thermodynamic parameters of the OTA/DIMEB complex were determined by means of the modified Benesi-Hildebrand equation and van’t Hoff plot. A 1:1 stoichiometry for the OTA/DIMEB complex was observed with a binding constant equal to 530 ± 50 L·mol−1 at 25 °C. The calculated thermodynamic parameters indicate that the interaction is highly endothermic and that the complex formation is driven by entropy. The results provide useful information for potential applications of cyclodextrins in the analysis of mycotoxins and in the field of mycotoxin sequestering agents.

The pH-related characteristics of 4-thiothymidine and its stability during prolonged exposure, at room temperature, to a neon lamp emitting in the 400–700 nm wavelength range were investigated by different spectroscopic techniques (UV-Vis, FTIR-ATR, 1H-NMR) and by ElectroSpray Ionization Mass Spectrometry (ESI-MS). The evaluation of the nucleoside photostability was performed as a control, with the perspective of studying its reactivity under the same conditions but in the presence of visible light-absorbing photosensitizers, able to generate reactive oxygen species. The comparison between UV-Vis spectra recorded at different pH values in the 7–12 range suggested the presence of an equilibrium related to the deprotonation of the N3–H group of 4-thiothymidine, with a pKa estimated to be close to 9. Some effects of the deprotonation occurring at alkaline pH were observed also in FTIR-ATR spectra, the main feature being the appearance of a band related to CN stretching, interpreted with the assumption of a partial double bond character by C2–N3, N3–C4 and C2–O− bonds, as a consequence of negative charge delocalization on the pyrimidine ring. As for photostability, UV-Vis, FTIR-ATR and NMR measurements suggested the generation of thymidine as a by-product but only after a prolonged (48 hours) irradiation time, whereas no significant alteration occurred in a shorter time range (1–2 hours), i.e. the one that will be considered in future studies involving the presence of photosensitizers. The nucleoside stability up to 2 hours of irradiation was confirmed by ESI-MS analyses; furthermore, on the other hand, the latter indicated the presence of three additional by-products, besides thymidine, after 48 hours of irradiation. In particular, an hydroxylated form of 4-thiothymidine and two dimeric species, characterized by S–S and S–O covalent bridges between two 4-thiothymidine and a 4-thiothymidine and a thymidine molecule, respectively, were detected.

A torsion test on hour‐glass‐shaped samples with a full joined or a ring‐shaped joined area was chosen to measure shear strength of glass–ceramic joined silicon carbide. Shear strength of about 100 MPa was measured for full joined SiC with fracture completely inside their joined area. Attempts to obtain this shear strength with a ring‐shaped joined area failed due to mixed mode fractures. On the contrary, full joined and ring‐shaped steel hour‐glasses joined by a glass–ceramic gave the same shear strength, thus suggesting that this test measures shear strength of joined components only when their fracture is completely inside their joined area.

Photosystem II (PSII) proteins from spinach leaves were immobilized onto quartz substrates according to the Layer-by-Layer (LbL) procedure, alternating protein to polyethylenimine (PEI) layers by exploiting electrostatic interactions. The effects of several factors, such as storage conditions, ageing of the PSII-modified substrates, as well as PSII concentration in buffer, on the quality of the prepared multilayers, were investigated by UV–vis Absorption Spectroscopy and Atomic Force Microscopy (AFM). A number of 13 layers was found to be optimal to guarantee intense PSII optical signals with homogeneous morphological distributions of proteins. The multilayers resulted stable if stored in contact with air at 4 °C, as observed by UV–vis Absorption spectra recorded after 48 h. The best results in terms of AFM images and electron transfer efficiency (measured by Hill Reaction assays) were gained by using 5.6 × 10−7 M chlorophyll concentration, obtaining multilayers with the most ordered protein distributions and the highest electron transfer efficiency, i.e. 85 % of an iso-absorbing PSII suspension. The results highlight the possibility to successfully immobilize PSII proteins, without considerable loss of bioactivity, thanks to the mild nature of the electrostatic LbL technique, opening up possibilities of applications in the bioelectrochemical energy conversion and biosensoristic fields.

In this paper, we report on the synthesis of pure silica (SiO2) nano- and microwires by a non-catalytic process. The structure, morphology and properties of the products were examined by scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy. The microstructural analysis shows that the SiO2 wires are high purity silica and are completely amorphous; their diameter ranges from 70 nm to 2 μm. The fiber length varies from 100 μm to several mm. The wire manufacturing process involves reduced temperatures and times (1000 °C, 30 min) compared to other processes, without needing any catalyst and has been carried out on different kinds of substrates (SiC and Si). Successful growth of SiO2 wires on the surface of silicon microcantilevers has been demonstrated; they could be used as an alternatively way to enhance the sensor performances.

In this study focus is posed on an innovative joint between a Carbon Fiber reinforced carbon–matrix Composite (CFC) and copper (Cu or its alloys) based on the modification of the CFC substrate and on a one-step brazing process with a non-active brazing alloy. To assess the mechanical response of the joint subjected to shear tests, a numerical–experimental methodology is presented herein, which consists of two inverse problems in a sequence, coherently formulated and solved: (i) the “optical” inverse problem tackled by an improved 2D global Digital Image Correlation procedure, allowing one to reconstruct displacement fields from digital images; (ii) the “mechanical” inverse problem, exploiting kinematic full-field measurements and a finite element model to estimate the governing parameters for the joint. The proposed methodology can provide a useful feedback to improve the design process and the validation stage of innovative joining techniques.

The results of an experimental investigation on epoxy‐joined silicon carbide tested in shear mode by seven different configurations of torsion tests are presented and compared to results obtained by asymmetric four‐point bending. All samples have been joined by an epoxy adhesive (Araldite AV119) chosen to obtain several joined samples in a reasonable time. Advantages and disadvantages of each configuration are discussed with the aim of finding a suitable method to measure the shear strength of joined components.

Glass-ceramics can be versatile joining materials with tailorable thermal and mechanical properties; they are not affected by oxidation and can be used as pressureless joining materials above their glass softening point. The glassy phase can be minimized by a suitable thermal treatment in order to improve the glass-ceramic creep behaviour. The use of glasses and glass ceramics as sealants in solid oxide fuel cells and as joining materials for SiC-based materials will be discussed.

This work describes the design and development of new coloured glass-based coatings for Foamglas (R) substrates. Four kinds of pigments were added in different proportions (1 and 5 wt% respectively) to a borate glassy matrix (labelled as G7) by two different mixing techniques; the chosen pigments were goethite (alpha-FeOOH), acicular hematite (Fe2O3) spherical hematite and TiO2 coated hematite. No interaction occurred between the selected pigments and the G7 matrix and consequently no new phases were formed in the reported experimental conditions. Coatings on the Foamglas (R) substrates were sintered at 560 degrees C for 1 h and showed different porosity, pigment dispersion in the matrix and colour development, depending on the mixing technique.The porosity was exploited to add TiO2 coated hematite into the coating, for photo-catalytic purposes. Each coating was deposited without affecting the Foamglas (R) substrate porous structure. (C) 2012 Elsevier Ltd. All rights reserved.

The results of an experimental investigation on epoxy-joined silicon carbide tested in shear mode by four different configurations of torsion test are presented and compared to results obtained by asymmetric four-point bending and four different lap tests in compression. All samples have been joined by an epoxy adhesive (Araldite AV119) which is to be considered as a model brittle joining material chosen to obtain several joined samples in a reasonable time. Advantages and disadvantages of each configuration are discussed and compared to results previously obtained with epoxy-joined Carbon/Carbon composites and ceramics tested with the same methods.

This work describes the design and development of two new silica‐based glass‐ceramic coatings, suitable to be applied as slurries on a foam glass substrate. The coating process was optimized for both compositions, according to their sintering behavior. Scanning electron microscopy ( SEM ) observations and coefficient of thermal expansion ( CTE ) measurements revealed a good thermomechanical compatibility between the foam glass substrate and both coatings. The proposed coatings showed excellent chemical durability: no weight loss was observed after soaking in distilled water at 90°C for 16 days.

In order to investigate the effects of cryomaceration and reductive vinification on chemical and physical indices and on antioxidant compounds of Sauvignon blanc wines, four wine-making procedures were applied: traditional white vinification, skin cryomaceration, vinification in a reductive environment, and a combination of the last two procedures. Significant differences were highlighted by both conventional analyses and NMR spectroscopy. The strongest changes were for organic acid concentrations (tartaric, in particular) and phenolic content. Cryomaceration caused a strong precipitation of tartaric acid, which may be desired if grapes have high acidity values. Cryomaceration protected those flavans reactive with vanillin from the action of oxidative enzymes. Vinification in a reductive environment, alone or combined with a cryomaceration step, gave wines with the highest solids content and caused a greater extraction of phenolic compounds from skins compared to traditional winemaking or cryomaceration alone, due to SO2 solubilisation. Grape oenological expression can be strongly affected by the application of the investigated wine-making procedures.