Sorption dynamics in fixed‐beds of inert core spherical adsorbents including axial dispersion and Langmuir isotherm

The effects of axial dispersion and Langmuir isotherm on transient behavior of sorption and intraparticle diffusion in fixed‐beds packed with monodisperse shell‐type/inert core spherical sorbents are studied. The system of partial differential equations of the mathematical model is solved numerically using finite difference methods. Results are presented in the form of breakthrough curves for adsorption and desorption processes. Results reveal that the shape of the breakthrough curves is influenced by both hydrodynamic and kinetic factors. Hydrodynamic factor is governed by axial dispersion and is controlled by changes of Peclet number. Simulation results reveal that when linear adsorption isotherm is used, the effect of axial dispersion on breakthrough curves of the system is important for Peclet numbers smaller than 50, whereas, for Langmuir isotherm axial dispersion is considerable for Peclet numbers less than 80. In addition, effects of type of adsorption isotherms and size of adsorbents on breakthrough curves are investigated, and results are compared with existing reports in the pertinent literature. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

A Fully Differential Monolithic LNA With On-Chip Antenna for a Short Range Wireless Receiver

This letter presents the smallest reported 5 GHz receiver chip (1.3 mm²) with an on-chip antenna in standard 0.13 mum CMOS process. The miniaturization is achieved by placing the circuits inside a meandered antenna. The on-chip antenna is conjugately matched to the low noise amplifier (LNA) over a wide frequency range. The design methodology for co-design of the on-chip antenna and LNA is described. The LNA is completely differential, consumes only 8 mW of power and provides a gain of 21 dB. Design tradeoffs and measurement challenges are given.     

Evaluation of the Binding Kinetics of RHEB with mTORC1 by In-Cell and In Vitro Assays

The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is activated by the small G-protein, Ras homolog enriched in brain (RHEB–GTPase). On lysosome, RHEB activates mTORC1 by binding the domains of N-heat, M-heat, and the focal adhesion targeting (FAT) domain, which allosterically regulates ATP binding in the active site for further phosphorylation. The crucial role of RHEB in regulating growth and survival through mTORC1 makes it a targetable site for anti-cancer therapeutics. However, the binding kinetics of RHEB to mTORC1 is still unknown at the molecular level. Therefore, we studied the kinetics by in vitro and in-cell protein–protein interaction (PPI) assays. To this end, we used the split-luciferase system (NanoBiT^®) for in-cell studies and prepared proteins for the in vitro measurements. Consequently, we demonstrated that RHEB binds to the whole mTOR both in the presence or absence of GTPγS, with five-fold weaker affinity in the presence of GTPγS. In addition, RHEB bound to the truncated mTOR fragments of N-heat domain (∆N, aa 60–167) or M-heat domain (∆M, aa 967–1023) with the same affinity in the absence of GTP. The reconstructed binding site of RHEB, ∆N-FAT-M, however, bound to RHEB with the same affinity as ∆N-M, indicating that the FAT domain (∆FAT, aa 1240–1360) is dispensable for RHEB binding. Furthermore, RHEB bound to the truncated kinase domain (∆ATP, aa 2148–2300) with higher affinity than to ∆N-FAT-M. In conclusion, RHEB engages two different binding sites of mTOR, ∆N-FAT-M and ∆ATP, with higher affinity for ∆ATP, which likely regulates the kinase activity of mTOR through multiple different biding modes.     

Studies on the anodic and cathodic polarization of amalgams—V. the behaviour of tin amalgams in alkaline solutions

Tin-amalgams of varying concentrations were oxidized galvanostatically in 0·01, 0·10 and 2·00 N NaOH solutions at 25°C. For each amalgam and solution composition a number of constant polarizing currents were used and cyclization was repeated until the oxidation (reduction) features of the amalgam became apparent. Two different oxidation patterns were distinguished. The first describes the behaviour of all amalgams in 0·01, 0·1 N NaOH, and of concentrated amalgams in 2 N NaOH, and the second for the behaviour of dilute tin amalgams in 2 N NaOH solutions.     

Corrosion Behaviour of Manganese-Containing Stainless Steels. III. Their susceptibility towards pitting corrosion

The pitting susceptibility of stainless steels with (%) 17.39 Cr, 5.3 Ni, 0.3–13.9 Mn in chloride solutions have been studied by a potentiodynamic cyclic polarization technique in solutions 0.1 N H₂SO₄ + 0.9 N Na₂So₄ + various amounts of NaCl. At low NaCl concentrations no pronounced influence of the chloride can be found and even at medium concentrations the passivation behaviour is generally maintained; in this region, however, there is an increase of dissolution and passivation current densities. High chloride concentrations, however, result in pitting which may be completely suppressed by a cyclic (anodic/cathodic) polarization technique. As to pitting resistance an alloy containing (%) 17.3 Cr, 5.3 Ni, 5.6 Mn is comparable to the steel CrNi 18 9.     

Synthesis of new nitrile imines with Pyridazin-3(2H)-one moiety and their addition to some dipoles. I

The present work deals with the synthesis of 6-aryl-2-ethoxycarbonyl pyridazin-3(2H)-ones ( 2 ) as useful synthetic intermediates because they allow formation of a new hydrazides ( 3 ), hydrazidoyl chlorides ( 4 ) and the highly reactive nitrile imine species ( 5 ). Dimerization and reaction of the latter species with benzonitrile, benzaldehyde and their p-methoxy and p-nitro derivatives provides a convenient method for the synthesis of substituted 1, 2, 4, 5-tetrazines ( 6 ), 1, 2, 4-triazoles ( 7 ) and 1, 3, 4-oxadiazoles ( 8 ), respectively, with pyridazin-3(2H)-one moiety.     

Action of grignard reagents on 6-(α-styryl)pyridazin-3(2H)-ones; synthesis of some 4-Substituted 6-(α-Styryl)-pyridazin-3(2H)-ones

6(α-Styryl)pyridazin-3(2H)-ones ( 1a – e ) reacted with phenylmagnesium bromide and/or methylmagnesium iodide to give the 1,4-addition products, 4-phenyl and/or 4-methyl-6-(α-styryl)pyridazin-3(2H)-ones ( 3a–e ). The structures assigned to the products are established by electronic and infrared spectroscopy and by synthesis of authentic samples in most cases.     

Critical Analysis of Localization and Time Synchronization Algorithms in Underwater Wireless Sensor Networks: Issues and Challenges

Wireless Personal Communications - In underwater wireless sensor networks (UWSNs), localization and time synchronization plays a critical role among many underwater applications. However without...