Surface charge properties of Fe2O3 in aqueous and alcoholic mixed solvents

Iron oxide (Fe2O3) was identified and characterized by surface area, X-ray diffractometry, and FTIR analyses. Surface charge densities, point of zero charge (PZC), and surface ionization constants were determined from the potentiometric titration data in various aqueous and aqueous organic mixed solvents in the temperature range 293-313 K. The surface charge densities were observed to decrease with the increase in temperature and concentration of metal ions in both the aqueous and aqueous organic mixed solvents. The absolute values of the surface charge density were found to change in the order aqueous > aqueous/methanol > aqueous/ethanol. Further, the PZC of the iron oxide was observed to shift to the higher pH values in the order ethanol > methanol > aqueous solution, which indicated a decrease in the acidity of the surface -OH groups. The pKa1 and pKa2 values of iron oxide were also determined and then used for determination of the surface potential (psi0) of the solid in aqueous and aqueous organic mixed solvents. The surface potential-surface charge curves generally supplemented the results derived from psi0-pH curves.     

Multielement determination in water by instrumental neutron activation analysis

Instrumental neutron activation analysis /INAA/ technique has been applied to a water sample to determine the elemental concentrations. The sample was irradiated with a neutron flux of 1.2×10¹² n cm^–2 s^–1 for two different periods followed by counting at three different decay times, using two coaxial type high-resolution Ge/Li/ detectors. The dominant elements determined in the water sample are Ca, Cl, Na, Mg, and K present in ppm-level while Co, I, Mn, Sm, and Sb are present in smaller amounts, approximately on the average 0.01 ppm. Only traces of other elements such as the rare-earth elements, Ag, As, Ba, Cu, Cd, Fe, Sr, W, Zn, seem to be present in the water sample.     

Hybrid anion exchange membrane of hydroxyl-modified polysulfone incorporating guanidinium-functionalized graphene oxide

Incorporating nanofillers is an effective method to balance conductivity and mechanical strength of anion exchange membranes (AEMs). In this work, a series of AEMs were prepared via embedding guanidinium-functionalized graphene oxide (GGO) into un-quaternized, diethanolamine-modified polysulfone (HPSf). The improved hydrophilicity of HPSf allows for better compatibility between GGO and polymer and also gives higher water uptake, which is beneficial for facilitating ion transport and alleviating hydroxide attack. AEM of HPSf embedding an optimized amount of GGO (0.88 mmol g^?1) exhibits the highest conductivity of 11 mS cm^?1 at 30 °C, which is 38% higher than that of pristine PSf-GGO membrane. It also possesses excellent anti-swelling stability (9% swelling ratio at 60 °C). When treated with 1 M NaOH at 60 °C for 120 h, HPSf-GGO-25% experienced a conductivity decay by 25%. Our work provides a route to fabrication of hybrid AEMs with improved interface properties and well-balanced conductivity and robustness.     

Application of intense ion beams to planetary physics research at the Facility for Antiprotons and Ion Research facility

This paper presents detailed 2D hydrodynamic simulations of implosion of a multi‐layered cylindrical target that is driven by an intense uranium beam. The target is comprised of a thick, high‐Z, high‐ρ cylindrical shell that encloses a sample material (Fe in the present case). Two options have been used for the focal spot geometry: an annular form and a circular form. The purpose of this work is to show that an intense heavy‐ion beam can induce the extreme physical conditions in the sample material similar to those that exist in the planetary cores. In this study, we use parameters of the beam that will be generated at the Facility for Antiprotons and Ion Research (FAIR), Darmstadt, in a few years' time. Production of these high‐energy‐density (HED) samples will allow us to study planetary physics in the laboratory. It is to be noted that planetary physics research is an important part of the FAIR HED physics program. A dedicated experiment named LAboratory PLAnetary Sciences (LAPLAS) has been proposed for this purpose. These simulations show that in such experiments an Fe sample can be imploded to the Earth's core conditions and to those in more massive rocky planets called Super‐Earths. Similarly, implosion of hydrogen and water samples will generate the core conditions of solar and extrasolar hydrogen‐rich gas giants and water‐rich icy planets, respectively. The LAPLAS experiments will thus provide very valuable information on the equation of state and transport properties of matter under extreme physical conditions, which will help scientists understand the structure and evolution of the planets in our solar system as well as of the extrasolar planets.     

Crystal Structure Analysis of 1-Hydroxy-3,5-dimethoxy-9H-xanthen-9-one Isolated from Ajuga bracteosa Root Extract and Its Biological Studies

The structure of 1-hydroxy-3,5-dimethoxy-9 H-xanthen-9-one isolated from chloroform extract of Ajuga bracteosa root was analyzed by single-crystal X-ray diffraction. DPPH(1,1-diphenyl-2-picryl hydrazyl), ABTS(2,2?-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities(RSA) and Fe2+ chelating activities were carried out to determine the antioxidant potential of the compound. RSA values for the compound were 96%, 96% and 96% for all the three activities respectively at maximum concentration of the compound(100 μ gmL-1) with the IC50 values of 3.40, 4.86 and 0.10(μ gmL-1). Antidiabetic activities including antiglycation and α-glucosidase inhibition were also performed where the antiglycation activity was performed using two techniques including spectrofluorometric as well as spectrophotometric technique. Spectrofluorometric technique provided 97% antiglycation potential while 92% antiglycation potential was observed by spectrophotometric technique for the isolated compound. The compound at a concentration of 10 μ gmL-1 exhibited 31% α-glucosidase inhibitory potential with IC50 of 15.56 μ gmL-1. Antimicrobial activity data showed that the compound was active against all the studied pathogenic bacteria.     

Preconcentration and Determination of Toxic Metals by A New Calix[4]arene Bonded HPLC Column

The present study deals with the preconcentration and determination of toxic metal ions using p-tetranitrocalix[4]arene (3) appended silica-based new HPLC column. The synthesized material was characterized using Fourier transform infrared and scanning electron microscopy techniques. The sorption characteristics of the HPLC column were investigated for three toxic metals (Cd²⁺, Hg²⁺ and Pb²⁺) in column agreement. The experiments were performed in five steps that were monitored using a UV–visible diode-array detector. However, all the HPLC experimental results were reconfirmed by using atomic absorption spectrophotometer. The effect of concentration on the sorption efficiency of the column was evaluated for all the three metals and the data obtained were investigated using Langmuir, Freundlich and Dubinin–Redushkevich (D–R) sorption isotherms. The value of coefficient of determination (R ²), i.e. 0.99, suggested that the Freundlich sorption isotherm was found to be the best-fit model for all the three toxic metal ions, whereas, mean free energy was calculated from the D–R isotherm as 5.3, 5.7, and 5.8 kJ/mol for Pb²⁺, Cd²⁺, and Hg²⁺, respectively; suggesting that physical electrostatic force is involved in the sorption process. The developed method was validated for system efficiency, accuracy, and precision.

     

Enhanced Entanglement and Controlling Quantum Steering in a Laguerre–Gaussian Cavity Optomechanical System with Two Rotating Mirrors

Gaussian quantum steering is a type of quantum correlation in which two entangled states exhibit asymmetry. An efficient theoretical proposal is presented for the control of quantum steering and enhancement of entanglement in a Laguerre–Gaussian (LG) cavity optomechanical system. The system contains two rotating mirrors and a coherently driven optical parametric amplifier (OPA). The numerical results show significantly improved mirror-mirror and mirror-cavity entanglements by controlling the system parameters such as parametric gain, parametric phase, and the frequency of the two rotating mirrors. In addition to bipartite entanglement, our system also exhibits mirror-cavity-mirror tripartite entanglement as well. Another intriguing finding is the control of quantum steering, for which several results were obtained by investigating it for various system parameters. It is shown that the steering directivity is primarily determined by the frequency of two rotating mirrors. Furthermore, for two rotating mirrors, quantum steering is found to be asymmetric both one-way and two-way. Therefore, it can be asserted that the current proposal may help in the understanding of non-local correlations and entanglement verification tasks.     

An iterative algorithm based on -proximal mappings for a system of generalized implicit variational inclusions in Banach spaces

In this paper, we give the notion of M-proximal mapping, an extension of P-proximal mapping given in [X.P. Ding, F.Q. Xia, A new class of completely generalized quasi-variational inclusions in Banach spaces, J. Comput. Appl. Math. 147 (2002) 369–383], for a nonconvex, proper, lower semicontinuous and subdifferentiable functional on Banach space and prove its existence and Lipschitz continuity. Further, we consider a system of generalized implicit variational inclusions in Banach spaces and show its equivalence with a system of implicit Wiener–Hopf equations using the concept of M-proximal mappings. Using this equivalence, we propose a new iterative algorithm for the system of generalized implicit variational inclusions. Furthermore, we prove the existence of solution of the system of generalized implicit variational inclusions and discuss the convergence and stability analysis of the iterative algorithm.     

Conservation laws for Camassa–Holm equation, Dullin–Gottwald–Holm equation and generalized Dullin–Gottwald–Holm equation

In this paper we construct the conservation laws for the Camassa–Holm equation, the Dullin–Gottwald–Holm equation (DGH) and the generalized Dullin–Gottwald–Holm equation (generalized DGH). The variational derivative approach is used to derive the conservation laws. Only first order multipliers are considered. Two multipliers are obtained for the Camassa–Holm equation. For the DGH and generalized DGH equations the variational derivative approach yields two multipliers; thus two conserved vectors are obtained.     

Cohen-Macaulay monomial ideals with given radical

We study the set of Cohen-Macaulay monomial ideals with a given radical. Among this set of ideals are the so-called Cohen-Macaulay modifications. Not all Cohen-Macaulay squarefree monomial ideals admit nontrivial Cohen-Macaulay modifications. It is shown that if there exists one such modification, then there exist indeed infinitely many.