Spectroscopy of Hadrons with b Quarks from Lattice NRQCD

Preliminary results from an extensive lattice calculation of the B, B_c, and \Upsilon spectrum at quenched \beta = 6.0 are presented. The study includes radially and orbitally excited mesons, and baryons containing b quarks. The b quarks are formulated using NRQCD; for light and c quarks, a tadpole-improved clover action is used.Comment: talk given at LATTICE98(heavyqk), 3 pages LaTeX, 2 Postscript figure

Global Research Trends and Hot Topics on Library and Information Science: A Bibliometric Analysis

Abstract Background and objective: One of the approaches to represent scientific publications in a field of science is to determine research trends and hot topics. Therefore, this study aimed to determine the research trends on the Library and Information Science (LIS) in the Scopus database during 2011-2020 and specify the hot topics in this field from July 2020 to July 2021. Materials and Methods: This study used scientometric techniques. The research population consisted of all papers in the field of LIS from July 2011 to July 2021. The data were collected from the Scopus database. The results were limited to 2011-2020 for determining the research trends in the field of LIS and from July 2020 to July 2021 for specifying the hot topics in this field. Data were analyzed using the word co-occurrence and social network analysis techniques, and UCINet, NetDraw, and VOSviewer software were used to draw scientific maps and identify core topics and individuals. Results: The keywords Systematic Review (frequency=531) and Bibliometrics (frequency=51) had the highest and lowest frequencies, respectively. Libraries and information technology (n=151), research methods (n=70), and databases (n=23) were the three important topic clusters in the study area, in which the United States, China, and the United Kingdom were the three most active countries, respectively. The Department of Library and Information Science, University of London, with 71 documents, and the Department of Information Management, University of Punjab, with 55 documents, had the most significant contribution of article publication among the influential institutions. Moreover, Zhang, Yut, and Wang, Liying each with 27 documents, and Li, Xiano with 24 documents were three active and influential authors in this field. In addition, systematic review , diffusion pattern , and bibliometric were also three hot topics. Conclusion: This study revealed that the orientation of the LIS research is going from traditional topics toward novel and emerging technologies. The results of this study can provide valuable information to researchers in LIS at the domestic and international levels

Closed loop control of laserwelding using an optical spectroscopic sensor for Nd:Yag and CO2 lasers

Recent developments in laser joining show the applicability of spectral analysis of the plasma plume emission to monitor and control the quality of weld. The analysis of the complete spectra makes it possible to measure specific emission lines which reveal information about the welding process. The subsequent estimation of the electron temperature can be correlated with the quality of the corresponding weld seam. A typical quality parameter, for laser welds of stainless steel, is the achieved penetration depth of the weld. Furthermore adequate gas shielding of the welds has to be provided to avoid seam oxidation. In this paper monitoring and real-time control of the penetration depth during laser welding is demonstrated. Optical emissions in the range of 400nm and 560nm are collected by a fast spectrometer. The sensor data are used to determinethe weld quality of overlap welds in AISI 304 stainless steel sheets performed both with CW Nd:YAG and CO2 lasers. A PI-controller adjusts the laser power aiming at a constant penetration. Optical inspection of the weld surface and microscopic analysis of weld cross sections were used to verify the results obtained with the proposed closed-loop system of spectroscopic sensor and controller

Sustained, Photocatalytic CO₂ Reduction to CH₄ in a Continuous Flow Reactor by Earth-Abundant Materials: Reduced Titania-Cu₂O Z-Scheme Heterostructures

Photocatalytic conversion of CO₂ and water vapor to hydrocarbon fuels is a promising approach for storing solar energy while reducing greenhouse gas emissions. However, still certain issues including low product yields, limited photocatalyst stability and relatively high cost have hampered practical implementation of this technology. In the present work, a unique strategy is adopted to synthesize a stable, and inexpensive photocatalyst comprised of earth-abundant materials: a reduced titania-Cu₂O Z-scheme heterostructure. Under illumination for 6 h, the optimized reduced titania-Cu₂O photocatalyst enables 0.13 % photoreduction of highly diluted CO₂ with water vapors to 462nmol g⁻¹ of CH₄ while showing excellent stability over seven testing cycles (42 h). Our studies show the Z-scheme inhibits Cu₂O photocorrosion, while its synergistic effects with reduced titania result in sustained CH₄ formation in a continuous flow photoreactor. To the best of our knowledge stability exhibited by the reduced titania-Cu₂O Z-scheme is the highest for any Cu-based photocatalyst

AJK2011-03079 NUMERICAL SIMULATION OF POROUS MEDIUM INTERNAL COMBUSTION ENGINE

ABSTRACT Porous media (PM) has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power range, the extension of the lean flammability limits, and the low emissions of pollutants. Future internal combustion (IC) engines should have had minimum emissions level, under possible lowest fuel consumption permitted at all operational conditions. This may be achieved by realization of homogeneous combustion process in engine. In this paper, possibility of using PM in direct injection IC engine, with cylindrical geometry for PM to have homogeneous combustion, is examined. A three-dimensional numerical model for the regenerative engine is presented in this study based on a modified version of the KIVA-3V code that is very popular for engine simulation. Methane as a fuel is injected directly inside hot PM that is assumed mounted in cylinder head. Very lean mixture is formed and volumetric combustion occurs in PM. Mixture formation, pressure, temperature distribution in both phases of PM and in-cylinder fluid with the production of pollutants CO and NO, in the closed part of the cycle is studied. INTRODUCTION The most important issue of internal combustion engines that currently exists, is non-homogeneous mixture formation in the combustion chamber, which causes heterogeneous heat release and high temperature gradient in combustion chamber and thus production of pollutants such as NO x , unburned hydrocarbons, carbon monoxide, soot and suspended particles. To avoid the temperature gradient in IC engines, homogeneous charge compression ignition (HCCI) engines, as an option, have been proposed. Control problems with start of ignition time under variable engine operational conditions and heat release rate, in this type of engines exist. In such engines, lean mixtur