Synthesis and application of novel 1,2,3‐triazolylferrocene‐containing ionic liquid supported on Fe3O4 nanocatalyst in the synthesis of new pyran‐substituted Betti bases

A novel magnetic ferrocene‐labelled ionic liquid based on triazolium, [Fe₃O₄@SiO₂@Triazol‐Fc][HCO₃], has been synthesized and has been successfully introduced as a recyclable heterogeneous nanocatalyst. The catalytic activity of the novel magnetic nanoparticles was evaluated in the one‐pot three‐component synthesis of a wide variety of Betti bases. A simple, facile and highly efficient green method has been developed for the synthesis of kojic acid‐containing Betti base derivatives at room temperature. Additionally, this new protocol has notable advantages such as short reaction times, green reaction conditions, high yields and simple workup and purification steps. Also, the novel nanocatalyst could be easily recovered using an external magnetic field and reused for six consecutive reaction cycles without significant loss of activity. The newly synthesized nanocatalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller measurements.     

Optimal design of shock ignition target in order to stop generated hot electrons within the cold fuel

Generation of hot electrons (HEs) within ignitor pulse interaction with pre-compressed fuel is an important challenge in the shock ignition approach. Target optimization in order to prevent the destructive effects of HE is the main goal of the present work. In the first stage, the spectrum of electron energy generated during the interaction of ignitor pulse at different widths with the HiPER pre-compressed target has been estimated by applying particle simulation tool. Then, by changing the thickness of the cold fuel in the range of 185–225 μm, the corresponding areal densities are calculated using 1D hydrodynamic simulations. Finally, in order to assess the energy fusion yield, the iso-gain curves are obtained for different ignitor time windows as well as target thicknesses. Simulation results indicate that by decreasing the baseline, target thickness leads to a 17–70% increase in the fuel areal density. Subsequently, it has been demonstrated that by properly adjusting the parameters of ignitor pulse launch time and its width and employing a target with areal density high enough to stop the HEs, energy gain above 140 can be achieved. Optimal areas for shell thickness and ignitor time window are identified.     

Inside-tube solid-phase microextraction as an interlink between solid-phase microextraction and needle device for n-hexane evaluation in air and urine headspace

Monitoring the trace amount of chemicals in various samples remains a challenge. This study was conducted to develop a new solid-phase microextraction (SPME) system (inside-tube SPME) for trace analysis of n-hexane in air and urine matrix. The inside-tube SPME system was prepared based on the phase separation technique. A mixture of carbon aerogel and polystyrene was loaded inside the needle using methanol as the anti-solvent. The air matrix of n-hexane was prepared in a Tedlar bag, and n-hexane vapor was sampled at a flow rate of 0.1 L/min. Urine samples spiked with n-hexane were used to simulate the sampling method. The limit of detection using the inside-tube SPME was 0.0003 μg/sample with 2.5 mg of adsorbent, whereas that using the packed needle was 0.004 μg/sample with 5 mg of carbon aerogel. For n-hexane analysis, the day-to-day and within-day coefficient variation were lower than 1.37%, with recoveries over 98.41% achieved. The inside-tube SPME is an inter-link device between two sample preparation methods, namely, a needle trap device and an SPME system. The result of this study suggested the use of the inside-tube SPME containing carbon aerogel (adsorbent) as a simple and fast method with low cost for n-hexane evaluation.     

NOx photocatalytic degradation over ZnO–CdS heterostructure composite under visible light irradiation

Research on Chemical Intermediates - ZnO–CdS composites with different loadings of CdS were prepared by a simple wet chemical synthesis method for NOx degradation under visible light. The...     

Electrocatalytic H2 Generation from Water Relying on Cooperative Ligand Electron Transfer in “PN3P” Pincer-Supported NiII Complexes

Water is the most sustainable source for H₂ production, and the efficient electrocatalytic production of H₂ from mixed water/acetonitrile solutions by using two new air-stable nickel(II) pincer complexes, [Ni(κ³-2,6-{Ph₂PNR}₂(NC₅H₃)Br₂] (R=H I , Me II ) is reported. Hydrogen generation from H₂O/CH₃CN solutions is initiated at −2 V against Fc^+/0, and bulk electrocatalysis studies showed that the catalyst functions with an excellent Faradaic efficiency and a turnover frequency of 160 s⁻¹. A DFT computational investigation of the reduction behavior of I and II revealed a correlation of H₂ formation with charge donation from electrons originating in a reduced ligand-localized orbital. As a result, these catalysts are proposed to proceed by a novel mechanism involving electron/proton transfer between a Ni^0I species bonded to an anionic PN³P ligand (“L⁻/Ni^0I”) and a Ni^I-hydride (“Ni−H”). Furthermore, these catalysts are able to reduce phenol and acetic acid, more active proton sources, at lower potentials that correlate with the substrate pK_a.     

On topological centers induced by unitary representations

Archiv der Mathematik - Let $$(\pi ,\,H_\pi )$$ be a unitary representation of a locally compact group G. The characterization of the minimality of the topological center induced by $$\pi $$ is...     

Synthesis of 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) derivatives in water

An environmentally friendly and simple method for the synthesis of some 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) derivatives via a one-pot pseudo five-component reaction of hydrazine hydrate, ethyl acetoacetate and aldehydes in water using pyridine trifluoroacetate or acetic acid at 70 °C is reported.     

Real options analysis of investment in carbon capture and sequestration technology

Among a comprehensive scope of mitigation measures for climate change, CO₂ capture and sequestration (CCS) plays a potentially significant role in industrialised countries. In this paper, we develop an analytical real options model that values the choice between two emissions-reduction technologies available to a coal-fired power plant. Specifically, the plant owner may decide to invest in either full CCS (FCCS) or partial CCS (PCCS) retrofits given uncertain electricity, CO₂, and coal prices. We first assess the opportunity to upgrade to each technology independently by determining the option value of installing a CCS unit as a function of CO₂ and fuel prices. Next, we value the option of investing in either FCCS or PCCS technology. If the volatilities of the prices are low enough, then the investment region is dichotomous, which implies that for a given fuel price, retrofitting to the FCCS (PCCS) technology is optimal if the CO₂ price increases (decreases) sufficiently. The numerical examples provided in this paper using current market data suggest that neither retrofit is optimal immediately. Finally, we observe that the optimal stopping boundaries are highly sensitive to CO₂ price volatility.     

Condensation of an ideal gas with intermediate statistics on the horizon

We consider a boson gas on the stretched horizon of the Schwartzschild and Kerr black holes. It is shown that the gas is in a Bose?CEinstein condensed state with the Hawking temperature T _c =T _H if the particle number of the system be equal to the number of quantum bits of space-time $N \simeq{A}/{l_{p}^{2}}$ . Entropy of the gas is proportional to the area of the horizon (A) by construction. For a more realistic model of quantum degrees of freedom on the horizon, we should presumably consider interacting bosons (gravitons). An ideal gas with intermediate statistics could be considered as an effective theory for interacting bosons. This analysis shows that we may obtain a correct entropy just by a suitable choice of parameter in the intermediate statistics.