Isoscalar giant monopole resonance for drip-line and super heavy nuclei in the framework of relativistic mean field formalism with scaling calculation

We study the isoscalar giant monopole resonance for drip-lines and super heavy nuclei in the framework of relativistic mean field theory with a scaling approach. The well known extended Thomas-Fermi approximation in the nonlinear σ-ω model is used to estimate the giant monopole excitation energy for some selected light spherical nuclei starting from the region of proton to neutron drip-lines. The application is extended to the super heavy region for Z=114 and 120, which are predicted by several models as the next proton magic numbers beyond Z=82. We compared the excitation energy obtained by four successful force parameters NL1, NL3, NL3*, and FSUGold. The monopole energy decreases toward the proton and neutron drip-lines in an isotopic chain for lighter mass nuclei, in contrast to a monotonic decrease for super heavy isotopes. The maximum and minimum monopole excitation energies are obtained for nuclei with minimum and maximum isospin in an isotopic chain, respectively.     

Role of optical resonator on the pointing stability of copper vapor laser beam

This paper presents a first comprehensive study on the pointing stability of copper vapor laser with an emphasis on bringing out the role of optical resonator. Long term (∼10 min), single pulse, far-field beam pointing stability of a 5.5 kHz repetition rate copper vapor laser (λ = 510 nm) with plane-plane, unstable and filtering resonators, is studied. It is established that the resonator optics largely decides the CVL pointing stability. Minimum beam pointing angle of 8 μrad from generalized diffraction filtered resonator (GDFR) is obtained in contrast to a maximum value of 120 μrad from the plane-plane resonator. The unstable resonators data is in between. The relative trends in CVL pointing stability are discussed in terms of wave-front distortions due to resonator mode build up from optical noise, thermal and mirror misalignment effects. The degree of optical resonator immunity to phase distortions dictates the net pointing stability achieved.     

Multi-objective geometric programming problem with ∊-constraint method

In multi-objective geometric programming problem there are more than one objective functions. There is no single optimal solution which simultaneously optimizes all the objective functions. Under these conditions the decision makers always search for the most “preferred” solution, in contrast to the optimal solution. A few mathematical programming methods namely fuzzy programming, goal programming and weighting methods have been applied in the recent past to find the compromise solution. In this paper ?$?$-constraint method has been applied to find the non-inferior solution. A brief solution procedure of ?$?$-constraint method has been presented to find the non-inferior solution of the multi-objective programming problems. Further, the multi-objective programming problems is solved by the fuzzy programming technique to find the optimal compromise solution. Finally, two numerical examples are solved by both the methods and compared with their obtained solutions.     

Alteration of selectivity in rhodamine based probes for Fe(III) and Hg(II) ion induced dual mode signalling responses

The probes for metal ion induced chromo- and fluorogenic signalling responses alter their selectivity depending upon the nature of substituent as well as a function of solvent medium. 2 has shown selectivity towards Fe(III) ion, 4 towards Hg(II) ion while 3 is responsive towards both Fe(III) and Hg(II) ions.     

OH···X (X = O, S) hydrogen bonding in thetrahydrofuran and tetrahydrothiophene

In this article, hydrogen bonding interaction between p-cresol (p-CR) and cyclic ether, tetrahydrofuran (THF) and thioether, tetrahydrothiophene (THT) has been investigated. Two-color resonantly enhanced two-photon ionization in conjunction with the fluorescence detected IR (FDIR) spectroscopy was used to record the changes in the OH stretching frequency in these complexes. The FDIR spectra showed existence of a single conformer of the p-CR·THF and two conformers of the p-CR·THT complex. With the help of computed IR spectra and atoms-in-molecules analysis, the two conformers of p-CR·THT were assigned as the complex of p-CR with THT (C(2))/THT (C(S)). The redshift of OH stretching frequency for the p-CR·THF complex was greater compared to those for the conformers of the p-CR·THT complex. The binding energies of the p-CR·THF and p-CR·THT complexes were computed to be 7.42 and 6.15 kcal/mole. These were of the same order as those for the acyclic analogs, diethylether (DEE), and diethylsulfide (DES), of the solvent molecules under investigation. Although the DEE and THF consist of same number of carbon atoms, the dispersion energy contribution was much higher (43%) for DEE than that for THF (30%). In the case of sulfur analogs, however, it was similar (~50%) in the case of both DES well as THT complexes. All the computed H-bond indicators for these two complexes nicely correlate with the observed redshift of the O-H stretch.     

Influence of the microstructure and its stability on the electrochemical properties of EMD produced from a range of precursors

The influence of the microstructure and the stable crystal structure on the electrochemical properties of the electrolytic manganese dioxide (EMD) produced from manganese cake (EMD_MC), low-grade manganese ore (EMD_LMO), and synthetic manganese sulfate solutions (EMD_SMS) is reported. X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry/differential thermal analysis, field emission scanning electron microscopy (FESEM), and chemical analyses were used to determine the structural and chemical characteristics of the EMD samples. The charge–discharge profile was studied in 9 M KOH using a galvanostatic charge–discharge unit. All the samples were found to contain predominantly γ-phase MnO₂, which is electrochemically active for energy storage applications. FESEM images show that preparation method significantly influences surface morphology, shape, and size of the EMD particles. In almost all cases, nanoparticles were obtained, with spindle-shaped nanoparticles for EMD_MC, platy nanoparticles in the case of EMD_LMO, and anisotropic growth of tetra-branched star-like nanoparticles of EMD_SMS. These nanoparticles arrange themselves in a near net-like fashion, resulting in porosity of the flakes of EMD during electrochemical deposition. Thermal studies showed loss of structural water and formation of lower manganese oxides. The EMD_MC showed superior discharge capacity of ~280 mAh g^?1 as compared to EMD_LMO (275 mAh g^?1) and EMD_SMS (245 mAh g^?1).     

Zeolitic Imidazolate Framework (ZIF)‐Derived,Hollow‐Core,Nitrogen‐Doped Carbon Nanostructures for Oxygen‐Reduction Reactions in PEFCs

The facile synthesis of a porous carbon material that is doped with iron‐coordinated nitrogen active sites (FeNC‐70) is demonstrated by following an inexpensive synthetic pathway with a zeolitic imidazolate framework (ZIF‐70) as a template. To emphasize the possibility of tuning the porosity and surface area of the resulting carbon materials based on the structure of the parent ZIF, two other ZIFs, that is, ZIF‐68 and ZIF‐69, are also synthesized. The resulting active carbon material that is derived from ZIF‐70, that is, FeNC‐70, exhibits the highest BET surface area of 262 m² g^?1 compared to the active carbon materials that are derived from ZIF‐68 and ZIF‐69. The HR‐TEM images of FeNC‐70 show that the carbon particles have a bimodal structure that is composed of a spherical macroscopic pore (about 200 nm) and a mesoporous shell. X‐ray photoelectron spectroscopy (XPS) reveals the presence of Fe‐N‐C moieties, which are the primary active sites for the oxygen‐reduction reaction (ORR). Quantitative estimation by using EDAX analysis reveals a nitrogen content of 14.5 wt. %, along with trace amounts of iron (0.1 wt. %), in the active FeNC‐70 catalyst. This active porous carbon material, which is enriched with Fe‐N‐C moieties, reduces the oxygen molecule with an onset potential at 0.80 V versus NHE through a pathway that involves 3.3–3.8 e^? under acidic conditions, which is much closer to the favored 4 e^? pathway for the ORR. The onset potential of FeNC‐70 is significantly higher than those of its counterparts (FeNC‐68 and FeNC‐69) and of other reported systems. The FeNC‐based systems also exhibit much‐higher tolerance towards MeOH oxidation and electrochemical stability during an accelerated durability test (ADT). Electrochemical analysis and structural characterizations predict that the active sites for the ORR are most likely to be the in situ generated N? FeN₂₊₂/C moieties, which are distributed along the carbon framework.     

Revisiting and enhancing electrochemical properties of SnO2 as anode for sodium-ion batteries

Journal of Solid State Electrochemistry - The tin oxide (SnO2) thin films have been prepared by the pulsed laser deposition (PLD) at deposition temperatures (Td) ranging from 300 to...     

Non-isothermal kinetics of melting and nematic to isotropic phase transitions of 5CB liquid crystal

This work reports a non-isothermal kinetics of the melting and the nematic to isotropic (N–I) phase transitions of the pentylcyanobiphenyl (5CB) liquid crystal compared with octylcyanobiphenyl (8CB) liquid crystal using calorimetric technique. Temperature scans and heating rate scans were performed for 5CB and 8CB from 280 to 333 K at various rates using differential scanning calorimetry from 0.5 to 20 K min⁻¹. Double activation was observed for 5CB for two heating rate regimes whereas 8CB indicated single activation only. The 5CB has smaller enthalpy and entropy of the transitions and needs larger activation than 8CB. This kinetic change can be explained in terms of the length scale and mobility of the liquid crystal molecules.     

Control of Porosity by Using Isoreticular Zeolitic Imidazolate Frameworks (IRZIFs) as a Template for Porous Carbon Synthesis

Herein, by using isoreticular zeolitic imidazolate frameworks (IRZIFs) as a template, we report the synthesis, morphology, and gas adsorption properties of porous carbon synthesized by a nanocasting method at 1000?°C, in which furfuryl alcohol (FA) was used as a carbon source. By using IRZIFs with variable porosity as templates, we could achieve control over the carbon porosity and H(2) and CO(2) uptake. The resultant microporous carbon C-70, synthesized by using ZIF-70 as the template, is the most porous (Brunauer-Emmett-Teller (BET) surface area 1510?m(2) g(-1) ). Carbon C-68, synthesized by using ZIF-68, has moderate porosity (BET surface area 1311?m(2) g(-1) ), and C-69, synthesized by using ZIF-69, has the lowest porosity in this series (BET surface area 1171?m(2) g(-1) ). The porous carbons C-70, C-68, and C-69, which have graphitic texture, have promising H(2) uptake capacities of 2.37, 2.15, and 1.96?wt?%, respectively, at 77?K and 1?atm. Additionally, C-70, C-68, and C-69 show CO(2) uptake capacities of 5.45, 4.98, and 4.54?mmol?g(-1) , respectively, at 273?K and 1?atm. The gas uptake trends shown by C-70, C-68, and C-69 clearly indicate the dependence of carbon porosity on the host template. Moreover, the as-synthesized carbons C-70, C-68, and C-69 show variable conductivity.