The development of porcelain foams lighter than water for heat isolation application

In this study, technological and heat isolation properties of porous ultra-lightweight porcelain foams were investigated. Traditional construction materials such as brick show good durability against environmental conditions. Bricks are also a good alternative compared to pumice blocks and autoclaved aerated concrete which are largely used as construction materials. Bricks are also more economical than the other construction materials. But they also have poorer thermal insulation properties. Among the construction material, XPS shows the best heat isolation properties. XPS (extruded polystyrene foam) is a polymeric material. Although XPS shows best heat insulation property, it easily flames. The aim of this study is developing porous porcelain isolation materials lighter than water by using a replication method and relatively better thermal isolation properties than the other construction materials.

     

Heterometallic Fe2II–UV and Ni2II–UV Exchange‐Coupled Single‐Molecule Magnets: Effect of the 3 d Ion on the Magnetic Properties

Uranium‐based compounds have been put forward as ideal candidates for the design of single‐molecule magnets (SMMs) with improved properties, but to date, only two examples of exchange‐coupled 3d–5f SMM containing uranium have been reported and both are based on the Mn^II ion. Here we have synthesized the first examples of exchange‐coupled uranium SMMs based on Fe^II and Ni^II. The SMM behavior of these complexes containing a quasi linear {M?O?U?O?M} core arises from intramolecular Fe?U and Ni?U exchange interactions combined with the high Ising anisotropy of the uranyl(V) moiety. The measured values of the relaxation barrier (53.9±0.9 K in the UFe₂ complex and of 27.4±0.5 K in the UNi₂ complex) show clearly the dependency on the spin value of the transition metal, providing important new information for the future design of improved uranium‐based SMMs.     

An Inverted‐Sandwich Diuranium μ‐η5:η5‐Cyclo‐P5 Complex Supported by U‐P5 δ‐Bonding

Reaction of [U(Tren^TIPS)] [ 1 , Tren^TIPS=N(CH₂CH₂NSiiPr₃)₃] with 0.25 equivalents of P₄ reproducibly affords the unprecedented actinide inverted sandwich cyclo‐P₅ complex [{U(Tren^TIPS)}₂(μ‐η⁵:η⁵‐cyclo‐P₅)] ( 2 ). All prior examples of cyclo‐P₅ are stabilized by d‐block metals, so 2 shows that cyclo‐P₅ does not require d‐block ions to be prepared. Although cyclo‐P₅ is isolobal to cyclopentadienyl, which usually bonds to metals via σ‐ and π‐interactions with minimal δ‐bonding, theoretical calculations suggest the principal bonding in the U(P₅)U unit is polarized δ‐bonding. Surprisingly, the characterization data are overall consistent with charge transfer from uranium to the cyclo‐P₅ unit to give a cyclo‐P₅ charge state that approximates to a dianionic formulation. This is ascribed to the larger size and superior acceptor character of cyclo‐P₅ compared to cyclopentadienyl, the strongly reducing nature of uranium(III), and the availability of uranium δ‐symmetry 5f orbitals.     

Catalytic Amine Oxidation under Ambient Aerobic Conditions: Mimicry of Monoamine Oxidase B

The flavoenzyme monoamine oxidase (MAO) regulates mammalian behavioral patterns by modulating neurotransmitters such as adrenaline and serotonin. The mechanistic basis which underpins this enzyme is far from agreed upon. Reported herein is that the combination of a synthetic flavin and alloxan generates a catalyst system which facilitates biomimetic amine oxidation. Mechanistic and electron paramagnetic (EPR) spectroscopic data supports the conclusion that the reaction proceeds through a radical manifold. This data provides the first example of a biorelevant synthetic model for monoamine oxidase B activity.     

High performance electrochemical sensor based on modified screen-printed electrodes with cost-effective dispersion of nanostructured carbon black

A novel sensor based on a screen-printed electrode (SPE) modified with a stable dispersion of commercially available carbon black (CB) N220 was developed. This probe showed significantly enhanced electrochemical activity relative to a bare SPE when tested with ferricyanide, epinephrine, norepinephrine, benzoquinone and NADH. When challenged in amperometric batch mode with NADH, the response was stable and revealed a linear dependence up to 2·10^?4 mol L^?1 with a detection limit of 3·10^?7 mol L^?1. The analytical performance, coupled with the low cost of the CB nanomaterial, suggests that this sensor holds promise for electrochemical applications.     

Synthesis and Structural, Magnetic and EPR Characterization of Discrete Finite Antiferromagnetic Chains

The synthesis, magnetic and electron paramagnetic resonance (EPR) characterisation of isolated, discrete, {Cr _n ^III } antiferromagnetically coupled chain complexes is reported for n = 6 and 7. Previous studies had reported supramolecular linked {Cr _n ^III } _x species. For n = 6, the lowest lying total spin state is diamagnetic with S = 1 and 2 first and second excited states, respectively; for n = 7, the lowest lying total spin state is S = 3/2 with S = 1/2 and 5/2 first and second excited states, respectively. The zero-field splittings of these states are well defined by low-temperature, multi-frequency EPR spectroscopy.     

Neutron correlations in 6He viewed through nuclear break-up

The nuclear break-up of ⁶He on a ²⁰⁸Pb target was studied at 20A MeV using a secondary beam of ⁶He produced by the SPIRAL facility at GANIL. $ \alpha$ -particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of ⁶He .     

Limits on intrinsic magnetism in graphene

We have studied magnetization of graphene nanocrystals obtained by sonic exfoliation of graphite. No ferromagnetism is detected at any temperature down to 2?K. Neither do we find strong paramagnetism expected due to the massive amount of edge defects. Rather, graphene is strongly diamagnetic, similar to graphite. Our nanocrystals exhibit only a weak paramagnetic contribution noticeable below 50?K. The measurements yield a single species of defects responsible for the paramagnetism, with approximately one magnetic moment per typical graphene crystallite.     

Determination of fourteen non-steroidal anti-inflammatory drugs in animal serum and plasma by liquid chromatography/mass spectrometry

The European Union has regulated the use of non-steroidal anti-inflammatory drugs (NSAIDs) in animal production and requires its member states to detect their residues in different matrices. In this work, a detailed MS and MS/MS study by ion-trap mass spectrometry of fourteen NSAIDs is described. Two multi-residue reversed-phase LC/ESI-MS/MS methods were developed, one for the determination of salicylic acid, naproxen, carprofen, flurbiprofen, ibuprofen, niflumic acid and meclofenamic acid in the negative ion mode, and the other for the determination of ketoprofen, suxibutazone, diclofenac, mefenamic acid, tolfenamic acid, phenylbutazone and its metabolite oxyphenbutazone in the positive ion mode. It was thus possible to confirm up to 14 different NSAID residues in serum and plasma samples of farmed animals, after chromatographic separation by a linear gradient. These substances were chosen as representative of different chemical subclasses of NSAIDs. The two methods were also validated in-house at three contamination levels, evaluating specificity and calculating mean recoveries, repeatability and within-laboratory reproducibility. The MS/MS product ion spectra were successfully used for the qualitative identification of all the drugs tested. All the NSAIDs, apart from salicylic acid, were recovered in high amounts, ranging between 71.6% and 100.9%.