Hairy foam : thin layers of carbon nanofibers as catalyst support for liquid phase reactions

Catalytic multiphase reactors are at the heart of many chemical industries.\ud They allow efficient contact between gas and/or liquid reactant phases with solid\ud catalysts increasing reaction rates. In practice, the higher reaction rates can be taken\ud advantage of only under the condition that the transfer of mass (reactant and products)\ud can keep up with the intrinsic activity of the catalysts used. In the case where mass\ud transfer is relatively slow, concentration gradients will occur, especially in the pore\ud system of a heterogeneous catalyst. Concentration gradients will also induce loss in\ud selectivity and byproducts are usually formed via reaction networks that often contain\ud parallel and consecutive reactions. Concentration gradients may thus prevent optimal\ud operation because the active catalytic sites experience different concentrations and at\ud least a part of the active sites operates under nonoptimal conditions. This problem is\ud most relevant when gases (e.g., hydrogen or oxygen) have to be dissolved in a liquid\ud (e.g., water) resulting in low concentrations. This coupled with the low diffusivity of\ud gases in liquids cause concentration gradients to occur even more easily.\ud Conventional multiphase reactors such as slurry phase reactor offers efficient mass\ud transfer but the rate per unit volume of the reactor is low and the cost for catalyst\ud separation is high. Whereas, trickle bed reactor pose mass transfer limitations,\ud pressure drop and fluid maldistribution. Structured reactors, especially foam type\ud internals exhibit low pressure drop and reduce fluid maldistribution. However,\ud structured internals have low specific surface area and this can be improved by\ud developing thin layer of carbon nanofibers (CNFs) on the surface of the support. Thin\ud layer of CNFs offers high surface, high porosity and low tortuosity, maximizing the\ud mass transfer rate which is particularly important for heterogeneous catalytic reactions\ud in liquid phase. The research described in this thesis is focused on preparing a CNF\ud layer on a structured foam support (termed as ‘Hairy foam’) and then evaluating the\ud performance of hairy foam catalyst in comparison to conventional porous catalysts

A Unified Approach to Access N-Acyl Sulfonamide Tethered Peptide Conjugates

Herein we demonstrate a chemoselective reaction of Nβ-protected amino alkyl sulfonyl azides with in situ generated Nα-protected amino acid selenocarboxylates via step wise intramolecular cyclization followed by decomposition to obtain N-acyl sulfonamide tethered peptidyl conjugates. The protocol offers the synthesis of orthogonally protected N-acyl sulfonamide tethered peptidomimetics under simple and mild reaction conditions employing commercially available amino acids in presence of NaBH2Se3 as a selenating agent. Also, the synthesis of N-acyl sulfonamide tethered amino acid and aryl conjugates were accomplished as an extension of the above strateg

On-chip microplasma reactors using carbon nanofibres and tungsten oxide nanowires as electrodes

Carbon nanofibres (CNFs) and tungsten oxide (W18O49) nanowires have been incorporated into a continuous flow type microplasma reactor to increase the reactivity and efficiency of the barrier discharge at atmospheric pressure. CNFs and tungsten oxide nanowires were characterized by high-resolution scanning electron microscopy, transmission electron microscopy and nanodiffraction methods. Field emission of electrons from those nanostructures supplies free electrons and ions during microplasma production. Reduction in breakdown voltage, higher number of microdischarges and higher energy deposition were observed at the same applied voltage when compared with plane electrodes at atmospheric pressure in air. Rate coefficients of electron impact reaction channels to decompose CO2 were calculated and it was shown that CO2 consumption increased using CNFs compared with plane electrode in the microplasma reactor

HUMAN ORGANIC SOLUTE TRANSPORTERS UTTERED IN SMALL INTESTINE, LIVER, AND KIDNEY FOR HOMEOSTASIS

The transporters participate in a significant role in drug absorption, distribution, metabolism, and elimination. Transporters are of efflux and influx type, need ATP-binding sites for their in and out movement across the cell membrane. These transporters play an important role in allowing or opposing the drugs into the cells, results in non-linearity in drug pharmacokinetics. A wide range of transporters was discovered; among them, organic solute transporters (OST) play a key role in drug absorption and disposition. Organic solute transporters is a heteromeric transporter localized to the basolateral of epithelial cells. It is the primary efflux bile acid transporter in the intestine of mammals

Precoded Large Scale Multi-User-MIMO System Using Likelihood Ascent Search for Signal Detection

Multiple antennas at each user equipment (UE) and/or thousands of antennas at the base station (BS) comprise the extremely spectrum efficient large scale multi-user multiple input multiple output system (BS). Due to space constraints, the closely spaced numerous antennas at each UE may cause inter antenna interference (IAI). Furthermore, when one UE comes into contact with another UE in the same cellular network, multi-user interference (MUI) may be introduced to the received signal. To mitigate IAI, efficient precoding pre-coding is necessary at each UE, and the MUI present at the BS can be canceled by efficient Multi-user Detection (MUD) techniques. The majority of earlier literature deal with one or more of these interferences. This paper implements a joint pre-coding and MUD, Lenstra-Lovasz (LLL) based Lattice Reduction (LR) assisted likelihood accent search (LAS) (LLL-LR-LAS), to mitigate IAI and MUI simultaneously LLL-based LR pre-coding mitigates IAI at each UE, and the LAS algorithm is a neighborhood search-based MUD that cancels BS MUI. The proposed approaches' performance was evaluated using Bit Error Rate analysis, and their complexity were determined using multiplication and addition.Dr. Mohammad Alibakhshikenari acknowledges support from the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant agreement No. 801538. Also, this work was supported by Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (Agencia Estatal de Investigación, Fondo Europeo de Desarrollo Regional-FEDER-, European Union) under the research Grant PID2021-127409OB-C31 CONDOR. Funding for APC: Universidad Carlos III de Madrid (Read & Publish Agreement CRUE-CSIC 2022)

Structural Analysis of Nano Core PCF With Fused Cladding for Supercontinuum Generation in 6G Networks

The Sixth Generation (6G) networks have identified the use of frequency range between 95 GHz and 3 THz with a targeted data rate of 1 Terabytes/second at the access network for holographic video applications. As is demands broadening of spectrum at the core network, this paper proposes a Supercontinuum Generation (SCG) through photonic crystal fiber (PCF) as it provides excellent broadening of the optical spectrum. Discussed in the paper is supercontinuum generation at high pumping power as per the standards specified by the International Telecommunications Union. The proposed PCF is designed with silicon nanocrystal core and the cladding microstructures is arranged in a fusion approach to effectively optimize the optical parameters such as dispersion, nonlinearity, birefringence, group-velocity dispersion, and confinement loss. The fused cladding comprises of a flower-cladding assembly in which air-holes arrangement is inspired from petals in a pleated structure. Such arrangement is shown here to provide high nonlinearity and negative dispersion for high power supercontinuum generation. The novel nanocore assembly with improved structural constraints delivers a non-linearity of 6.37 × 106 W−1 km−1 and a negative dispersion of −142.1 (ps/nm-km) at 1,550 nm. Moreover, a supercontinuum spectrum is generated using different pulse widths ranging from 350 to 650 ps with 25 kW pump power for PCF lengths of 10 and 15 mm

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

[EN] The aim of this work is to study the activity for the nitrate catalytic reduction in natural water, using a continuous stirred tank reactor, of Pd/Cu and Pd/Sn catalysts supported on different materials. The studied supports are: -Al2O3 (commercial), active carbon, graphite, hydrotalcite and alumina synthesized in our laboratory with a high surface area. The activity and selectivity of the catalysts supported on these materials have been compared. The best results have been obtained with the Pd/Sn catalysts supported on alumina. These results show thatthe surface area ofthe supportis notthe only important characteristic for an active catalyst in this reaction, but also its acid–base properties, electrical conductivity and interaction with the metallic active sites are very significant. The adequate combination of these characteristics is necessary to obtain an active catalyst. The influence of the Pd/Sn content on the activity of the alumina supported catalysts was studied, observing that the best activity was obtained when the Pd/Sn ratio was higher than 1. This result clearly indicates that it is necessary to have both Pd and Pd–Sn centers in order to obtain an active catalyst.The authors thank the Spanish Government(projects MAT2009-14528-C02-01 and CONSOLIDER INGENIO 2010) and the European Union (European Community’s Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 226347 Project)for the financial support.Franch Martí, C.; Palomares Gimeno, AE.; Corma Canós, A. (2011). A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor. Catalysis Today. 172(1):90-94. https://doi.org/10.1016/j.cattod.2011.05.015S9094172

Review on unmanned aerial vehicle assisted sensor node localization in wireless networks: soft computing approaches

Node positioning or localization is a critical requisite for numerous position-based applications of wireless sensor network (WSN). Localization using the unmanned aerial vehicle (UAV) is preferred over localization using fixed terrestrial anchor node (FTAN) because of low implementation complexity and high accuracy. The conventional multilateration technique estimates the position of the unknown node (UN) based on the distance from the anchor node (AN) to UN that is obtained from the received signal strength (RSS) measurement. However, distortions in the propagation medium may yield incorrect distance measurement and as a result, the accuracy of RSS-multilateration is limited. Though the optimization based localization schemes are considered to be a better alternative, the performance of these schemes is not satisfactory if the distortions are non-linear. In such situations, the neural network (NN) architecture such as extreme learning machine (ELM) can be a better choice as it is a highly non-linear classifier. The ELM is even superior over its counterpart NN classifiers like multilayer perceptron (MLP) and radial basis function (RBF) due to its fast and strong learning ability. Thus, this paper provides a comparative review of various soft computing based localization techniques using both FTAN and aerial ANs for better acceptability