Transition Metal Substituted Polyoxotungstates in the Catalytic Oxidation of 1H-Indene and 1,2-Dihydronaphthalene with Hydrogen Peroxide

The oxidation of 1H-indene and 1,2-dihydronaphthalene with hydrogen peroxide in the presence of Mn(III) or Fe(III) substituted Keggin-type polyoxotungstates is described. The products obtained depend on the catalyst and reaction conditions. Ring cleavage was observed, affording dialdehydes under mild and environmentally friendly conditions. Other main products were the α-hydroxy-ketones. The resulting epoxides seem to be intermediates to other oxygenated products.     

Analytical relationship determining the oscillation period of heat-integrated homogeneous tubular chemical reactor without dispersion

The derived mathematical formulae enable the exact calculation of the period of temperature and concentrations oscillations of a non-adiabatic homogeneous tubular reactor with the external shell-and-tube heat exchanger. The derivations refer to both cocurrent and countercurrent exchanger.     

Molecular speciation of sulfur in solid oxide fuel cell anodes with X-ray absorption spectroscopy

Two sets of solid oxide fuel cell (SOFC) electrode assemblies from different manufacturers were run under different operating conditions with different sulfur exposure, and then subjected to X-ray absorption spectroscopy (XAS) at the sulfur K (1s) edge. Within the detection limits of the spectrometer, pristine fuel electrodes (anodes) show no traces of sulfur. The anodes operated with sulfur-containing natural gas and H₂S doped natural gas show spectra rich in sulfur structures. Two other electrodes run with sulfur-containing natural gas, one with a sulfur filter and the other without, show an XAS spectrum with a very broad peak, covering the entire sulfur absorption range, and thus not allowing for identification of specific sulfur signatures. These appear to be the first ever reported sulfur XAS data on SOFC anodes, and the XAS technique shows promise to resolve some hitherto unsolved issues on sulfur poisoning of SOFC, particularly regarding the molecular speciation of the sulfur components.     

Omega‐3 and Polyunsaturated Fatty Acids‐Enriched Hamburgers Using Sterol‐Based Oleogels

Obesity and cardiovascular diseases are among the most worrying health problems worldwide. Dietary habits can be catalysts for the rise of these health issues in western countries. In this work, a meat product (pork patties) commonly elaborated with a high fraction of saturated fat is reformulated with an oleogel based on linseed oil (rich in polyunsaturated fatty acids). The oleogel is used for the partial replacement of the solid fat fraction present in pork patties (H‐25 for 25% and H‐75 for 75% of replacement). Incorporation of oleogels results in the modification of the fatty acid profile and in the significant decrease of the omega‐6/omega‐3 ratio. Results show that for both degrees of fat substitution, there are no differences between the patties produced with oleogel incorporation and the control, regarding textural parameters such as hardness, cohesiveness, and chewiness. Overall, samples with less amount of oleogel (H‐25) are well classified in the acceptance and preference tests, despite the clear preference among the sensorial panel toward the control samples. These results show the feasibility of introducing oleogels as a fat replacer in the manufacturing process of pork patties, though there is still work to be done regarding some of their sensorial attributes. Practical Applications: The purpose of this work is focused on the study of the properties of meat patties after the replacement of saturated fat with a multicomponent oleogel, foreseeing the hamburger production. The results show that the oleogel incorporation in meat patties is possible at the industrial level without additional unitary steps during meat patty production. Based on this work it is possible to produce meat patties with adjusted fatty acids profiles.     

On plane stress state and stress free deformation of thick plate with FGM interface under thermal loading

This paper demonstrates the plane stress state and the stress free thermo-elastic deformation of FGM thick plate under thermal loading. First, the Sneddon-Lockett theorem on the plane stress state in an isotropic infinite thick plate is generalized for a case of FGM problem in which all thermo-mechanical properties are optional functions of depth co-ordinate. The proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations that reduces it to the plane stress state problem. Then an existence of the purely thermal deformation is proved in two ways: first, it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient, second, proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation if only stress field is homogeneous in domain and at boundary. Finally, couple examples of application to an engineering problem are presented.     

The impact of bed temperature on heat transfer characteristic between fluidized bed and vertical rifled tubes

In the present work, the heat transfer study focuses on assessment of the impact of bed temperature on the local heat transfer characteristic between a fluidized bed and vertical rifled tubes (38mm-O.D.) in a commercial circulating fluidized bed (CFB) boiler. Heat transfer behavior in a 1296t/h supercritical CFB furnace has been analyzed for Geldart B particle with Sauter mean diameter of 0.219 and 0.246mm. The heat transfer experiments were conducted for the active heat transfer surface in the form of membrane tube with a longitudinal fin at the tube crest under the normal operating conditions of CFB boiler. A heat transfer analysis of CFB boiler with detailed consideration of the bed-to-wall heat transfer coefficient and the contribution of heat transfer mechanisms inside furnace chamber were investigated using mechanistic heat transfer model based on cluster renewal approach. The predicted values of heat transfer coefficient are compared with empirical correlation for CFB units in large-scale.     

Relationship between Antioxidant Activity and Ligand Basicity in the Dipicolinate Series of Oxovanadium(IV) and Dioxovanadium(V) Complexes

Oxidative stress plays an important role in the pathogenesis of many serious diseases, including cancer, atherosclerosis, coronary artery disease, Parkinson’s disease, Alzheimer’s disease, stroke and myocardial infarction. In the body’s natural biochemical processes, harmful free radicals are formed, which can be removed with the help of appropriate enzymes, a balanced diet or the supply of synthetic antioxidant substances such as flavonoids, vitamins or anthocyanins to the body. Due to the growing demand for antioxidant substances, new complex compounds of transition metal ions with potential antioxidant activity are constantly being sought. In this study, four oxovanadium(IV) and dioxovanadium(V) dipicolinate (dipic) complexes with 1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy) and the protonated form of 2-phenylpyridine (2-phephyH): (1) [VO(dipic)(H₂O)₂]·2 H₂O, (2) [VO(dipic)(phen)]·3 H₂O, (3) [VO(dipic)(bipy)]·H₂O and (4) [VOO(dipic)](2-phepyH)·H₂O were synthesized including one new complex, so far unknown and not described in the literature, i.e., [VOO(dipic)](2-phepyH)·H₂O. The oxovanadium(IV) dipicolinate complexes with 1,10-phenanthroline and 2,2′-bipyridyl have been characterized by several physicochemical methods: NMR, MALDI-TOF-MS, IR, but new complex [VOO(dipic)](2-phepyH)·H₂O has been examined by XRD to confirm its structure. The antioxidant activities of four complexes have been examined by the nitrotetrazolium blue (NBT) method towards superoxide anion. All complexes exhibit high reactivity with superoxide anion and [VOO(dipic)](2-phepyH)·H₂O has higher antioxidant activity than L-ascorbic acid. Our studies confirmed that high basicity of the auxiliary ligand increases the reactivity of the complex with the superoxide radical.     

Ion–molecule reactions in mixtures of ethane with carbon tetrafluoride

Ion–molecule reactions have been measured for the ethane–carbon tetrafluoride mixtures of different compositions using a quadrupole mass spectrometer with a high-pressure ion source. Concentration of ethane in these mixtures ranged from 10% to 90% (at 10% increment). The following primary and secondary ions: CH₃⁺, F⁺, C₂H₃⁺, C₂H₄⁺, C₂H₅⁺, C₂H₆⁺, C₃H₅⁺, C₃H₇⁺, C₄H₇⁺, C₄H₉⁺, C₄H₁₀⁺, C₄H₁₁⁺ and CF₃⁺ were observed. Relative ion current intensities for primary and secondary ions are presented as a function both of total mixture pressure and concentration of carbon tetrafluoride in the mixture. Primary ions were produced by electrons with the energy of 300 eV. Potential of repeller electrode inside the ion source collision chamber was fixed at 5 V for all measurements. The total mixture pressure was changed from 0.7 to 26.6 Pa. Schemes of ion–molecule reactions were proposed.