[en] A full-sized model for the horizontally oriented metal cask containing 21 spent fuel assemblies has been considered to evaluate the internal natural convection behavior within a dry shield canister (DSC) filled with helium as a working fluid. A variety of two-dimensional CFD numerical investigations using a turbulent model have been performed to evaluate the heat transfer characteristics and the velocity distribution of natural convection inside the canister. The present numerical solutions for a range of Rayleigh number values (3 Χ 10⁶∼3 Χ 10⁷) and a working fluid of air are further validated by comparing with the experimental data from previous work, and they agreed well with the experimental results. The predicted temperature field has indicated that the peak temperature is located in the second basket from the top along the vertical center line by effects of the natural convection. As the Rayleigh number increases, the convective heat transfer is dominant and the heat transfer due to the local circulation becomes stronger. The heat transfer characteristics show that the Nusselt numbers corresponding to 1.5 Χ 10⁶ < Ra < 1.0 Χ 10⁷ are proportional to 0.5 power of the Rayleigh number, while the Nusselt numbers for 1.0 Χ 10⁷ < Ra < 8 Χ 10⁷ are proportional to 0.27 power of the Rayleigh number. These results agreed well with the trends of the experimental data for Ra>1.0 Χ 10⁷

[en] The phase behavior of the multi-component polymer systems such as blends and block copolymers (BCPs) has been studied extensively, as it determines the chemical and physical properties of the polymeric materials in practical applications. Above all, polymer baroplasticity is a desirable property for the recycling and regenerating industries, since it allows the polymers to flow at relatively mild pressure. Particularly, the compressibility issue on the enhanced miscibility with pressure has been an attractive topic, because an ordered state of the baroplastic BCPs becomes a phase-mixed state (or disordered phase) between the two dissimilar blocks upon pressurizing. This is in contrast to the incompressibility that was dictated by the enthalpic effect arising from the increased unfavorable contacts between the two blocks by increasing pressure. The phase behaviors of BCP blends composed of the weakly interacting (with no specific interaction) polystyrene-b-poly(n-butyl methacrylate) (PS-b-PnBMA) and deuterated polystyreneb- poly-(n-hexyl methacrylate) (dPS-b-PnHMA) were investigated by Small-Angle Neutron Scattering(SANS) and Depolarized Light Scattering (DPLS) measurements. Interestingly, pressure dependence of various phase transitions for the miscible BCP blends was significantly changed, in which the blends consist of a PS-b-PnBMA and a deuterated dPS-b-PnHMA. To elucidate the origin and difference in baroplasticity of weakly interacting BCP blends, the pressure dependence of transition temperatures was evaluated using enthalpic and volumetric changes at phase transitions. We also demonstrate that the entropic compressibility for the miscible BCP blends is a baroplastic indicator, which was characterized by the negative volume change on mixing (ΔVmix) at transitions.

[en] The potential energy curves between the 10 lowest electronic states of KCs molecule have been evaluated in a wide R range by means of shape and energy consistent small core (9 electrons)quasi relativistic effective core potentials (ECPs). To minimize systematic R dependent errors (first of all basis set superposition errors)in the ordinarily derived ab initio curves Uι"ab", the adiabatic potentials for all excited states treated were constructed through the simple relation:Uι"dif"(R)=[Uι"ab"(R)-U"Χ""ab"(R)]+U"Χ""emp"(R), where U"Χ""emp"and U"Χ""ab"are the highly accurate empirical and present ab initio ground state potentials, respectively. Spin orbit coupling matrix elements are the most pronounced among considering non adiabatic interactions while L uncoupling effect could not be neglected especially for the high J values. Moreover, there are also strong radial coupling effects between the 2"3"S"+"states at small inter nuclear distance

[en] Highlights: • Imidazolium-based ionic salt (LiFSMIPFSI) was prepared as an electrolyte for LIBs. • LiFSMIPFSI electrolyte showed good ionic conductivity and LIB performance. • LiFSI and LiTFSI were added as additives to enhance the performance of LiFSMIPFSI. • LiFSMIPFSI with LiFSI additive delivered a maximum capacity of 147 mAhg⁻¹. • The electrolyte without/with additives showed good capacity retention. -- Abstract: Herein, we report the synthesis of a novel imidazolium-based ionic salt, lithium (fluorosulfonyl) ((3-(1-methyl-1H-imidazol-3-ium-3-yl)propyl)sulfonyl) bis(fluorosulfonyl)imide (LiFSMIPFSI) as an electrolyte for the application in lithium-ion battery (LIB). The as-synthesized LiFSMIPFSI exhibited high purity and yield, which was characterized by various spectroscopic techniques. The LiFSMIPFSI electrolyte with a mixed solvent of ethylene carbonate (EC) and dimethyl sulfoxide (DMSO) (75:25 v/v) showed a wide electrochemical stability (ca. 4.5 V vs. Li/Li⁺) and high thermal stability (300 °C), good Li⁺ conductivity (ca. 8.02 mS/cm at 30 °C), and low intrinsic viscosity, which concurrently delivered a specific discharge capacity of ca. 125 mAhg⁻¹ at 0.1 C with the full LIB configuration of LiFePO₄/electrolytes/graphite. The performance of this LiFSMIPFSI electrolyte was enhanced further by the addition of conventional lithium bis(fluoro-sulfonyl)imide (LiFSI) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) ionic salts (20% each) as additives with the specific discharge capacity of ca. 147 and 139 mAhg⁻¹, respectively, at 0.1 C. This is mainly due to the additional enhancement of Li⁺ conductivity and its concentrations in the electrolytes induced by the additives. The LiFSMIPFSI electrolyte with LiFSI additive based LIB showed the highest cycling stability (capacity retention ca. 97%) among the electrolytes after 500 charge-discharge cycles. Thus, the present work contributes to the development of new ionic salts and its effects upon the addition of additives on LIB performance.

[en] We show that the multiplicative product of a molecular-beam excitation spectrum and an ultracold-molecule excitation spectrum, with a frequency offset appropriate to the initial ultracold-molecule level, provides the relative rate of stimulated Raman transfer (SRT) from a given high rovibrational level to the lowest rovibronic level, i.e., the v^''=0,J^''=0 level of the ground electronic state for photoassociated (and magnetoassociated) ultracold molecules. This product spectrum clearly indicates the optimal pathways for SRT, even when the two component spectra are completely unassigned. We illustrate this specifically for the case of KRb.

[en] The primary aim of this work was to study the diseased and healthy rice plant samples at the elemental and molecular level to get the proper understanding of the causes and the chemical changes occurred in the healthy rice grains with the infestation due to false smut disease. We have used microscopic and isolation methods to detect and identify the presence of the species of pathogen involved in the diseased rice plant samples. Elemental analyses of rice grains were carried out using laser-induced breakdown spectroscopy (LIBS) and wavelength dispersive X-ray fluorescence (WDXRF) spectrometry. This revealed the mineral changes appeared in diseased rice plant samples due to the invasion of pathogens. The results from LIBS and WDXRF showed that the mineral elements such as calcium (Ca), magnesium (Mg), silicon (Si), copper (Cu) and iron (Fe) decreased in diseased rice grains than those of healthy rice grains whereas some elements showed their variable behavior in diseased rice grains than those of healthy grains. The results obtained by LIBS is in close agreement with the results obtained by WDXRF. We have employed Fourier-transform infrared (FTIR) spectroscopy to study the molecular changes appeared in the active bio compounds of the rice grains due to the infection caused by false smut. The present spectroscopic studies would provide the proper understanding of the rice false smut disease and also help in developing the proper treatment strategies to prevent the further yield loss caused by the rice false smut disease.

[en] We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results. - Highlights: • Broadband LIBS spectra of various edible sea salts were obtained. • Intensity correlation of emission lines of the elements in edible sea salts was analyzed. • The elements were categorized into three groups with independent discriminating power. • The effective combination of a few lines can provide dependable classification models

[en] Highlights: • Edible salts were classified by DORS (optical reflectance) and LIBS. • The classification performance of LIBS was better than that of DORS. • DORS possesses independent discrimination power from that of LIBS. • DORS-LIBS fused model provide better performance than separate DORS or LIBS models. Diffuse optical reflectance spectroscopy (DORS) and laser-induced breakdown spectroscopy (LIBS) were applied for classification of edible salts. DORS and LIBS spectra were recorded for 21 edible salts products. Principal component analysis was performed to reduce variables for each spectroscopic data. DORS and LIBS classification models using principal component scores of the calibration dataset were constructed. Each model was validated for external test dataset using the k-nearest neighbors algorithm. The LIBS model provided better classification accuracy than the DORS model. However, the DORS model showed higher accuracy for particular salt samples. This indicates that reflectance spectra possess independent chemical information from that provided by LIBS spectra. Complementary effects of DORS and LIBS on improving the classification accuracy were investigated for the classification problem composed of selected samples. DORS-LIBS fused models were constructed with different weighting factors for DORS variables. The optimum fused model showed higher classification accuracy than those of either DORS or LIBS models. Our results suggest that the two simple spectroscopic techniques can be combined for highly accurate classification of edible salt products.

[en] Highlights: • Remote LIBS analysis of cerium in the samples located behind a shielding window. • Effects of a shielding window on the remote LIBS analysis were investigated. • Multivariate analysis improves the calibration quality. - Abstract: Laser-Induced Breakdown Spectroscopy (LIBS) has been considered in many applications in nuclear industry. LIBS can be an ideal technique for analyzing the inaccessible nuclear materials typically located behind a shielding window. We report the effect of optical transmittance of the shielding window on the analytical performances of stand-off LIBS for the preliminary surrogate sample of demonstration pyrochemical process, a mixture of cerium oxide (CeO₂) and potassium chloride (KCl). A pulsed laser beam was focused on the surface of the sample located 1.45 m away from the stand-off LIBS device. The laser-induced plasma emission was collected through a Schmidt–Cassegrain telescope. LIBS spectra were obtained in an open path and through the shielding window. Univariate calibration curves were obtained using the integrated area of partially resolved Ce I and II lines. The limits of detection (LOD) for Ce were estimated to be 0.046 and 0.061 wt.% for the open-path and through-window analysis, respectively. We found that the through-window LOD is mainly influenced by the optical transmittance of the shielding window and therefore, the through-window LOD can be predicted from the open-path LOD and the optical transmittance of the shielding window. Also, multivariate calibration using partial least squares regression was successfully applied. The quality of calibration could be improved by the multivariate analysis

[en] We have observed dynamic effects of a pre-ablation spark on the signal intensity in the orthogonal dual-pulse laser-induced breakdown spectroscopy. We applied pre-ablation and ablation laser pulses with significantly reduced energy for an aluminum metal in open air. Under this experimental condition, the well-known signal enhancement through the increase in ablated mass was negligible. The Al I and II emissions were investigated by both top-view and spatially-resolved side-view collection modes. In this low laser power regime, dynamic effects of a pre-ablation spark on the signal intensity were clearly revealed. The principal factor of signal enhancement is the increase in temperature. Without the mass removal enhancement, effective rarefaction leads to decrease in the Al I emission intensity and simultaneous increase in the Al II emission intensity. This is attributed to the role of Saha equilibrium. Selective prolongation of emission lifetime only for the enclosed part of the analyte plasma in the rarefied region and other fluid-dynamic effects of a pre-ablation spark have been visualized by wavelength-selected time-space correlation maps of plasma emissions.