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In a plasma wakefield accelerator (PWFA), using advanced injection techniques such as the density down-ramp injection is a promising approach for generating electron beams with ultralow emittance. In this study, we describe how such a scheme could be realized using the beam from the Linac Coherent Light Source (LCLS) accelerator as a driver. Moreover, we explore the potential applications of such high-brightness e-beams in a facility like LCLS and in novel concepts for compact FELs. [ABSTRACT FROM AUTHOR]

By use of particle-in-cell (PIC) simulation, we observe ultra-bright XUV radiation pulses emerging from a laser wakefield driven above the wave-breaking threshold in underdense plasma, which is as short as a few hundred attoseconds in one-dimentsional simulations and a few femtoseconds in two-dimensional simulations. It is concerned with the formation of a transverse narrow current layer co-moving with the intense laser pulse. This current layer is formed by an electron density spike with trapped electrons in the wakefield with certain transverse kinetic momentum of electrons left behind the laser pulse. This net momentum appears when the driving laser pulse undergoes strong selfmodulation and subsequent pulse steepening at the front. In the multi-dimensional simulations, the XUV emission is found only near the laser axis with a much smaller spot size than the laser pulse due to the transverse dynamics of the trapped electrons. The present scheme provides an alternative method to produce ultra-bright XUV pulses for ultrafast applications. [ABSTRACT FROM AUTHOR]

Cavities embedded in photonic crystal waveguides offer a promising route towards large scale integration of coupled resonators for quantum electrodynamics applications. Here a strongly coupled system consisting of a single quantum dot and a cavity formed by the local width modulation of a photonic crystal waveguide is demonstrated. The resonance originating from the cavity is clearly identified from microphotoluminescence mapping of the scattered signal along the waveguide. The exciton-photon strong coupling regime is obtained by temperature control. [ABSTRACT FROM AUTHOR]

An air-blast atomizer employs kinetic energy of a flowing airstream to shatter liquid jet or sheet into ligaments and then drops. The atomizer can be designed in various configurations for different applications. In previous work, the household designed atomizer was manufactured and tested, in order to replace one in the commercial fogging sprayer. The spray characteristics were investigated through different angles of an air swirler. In this work, the effects of air-injection port diameter on the spray characteristics, velocity of single-phase airstream and drop size of discrete-phase spray, are numerically and experimentally studied. The atomizers with three different sizes of air-injection port are made by 3-D printing for experiment. The Malvern Spraytec is used to measure the spray drop size distribution. For the airstream velocity, the CFD simulation is applied. The results show that reducing the air-injection port diameter leads to the larger air velocity magnitude and then resulting in smaller drops. The higher velocity of the airstream with larger momentum also produces the better penetrating spray. [ABSTRACT FROM AUTHOR]

Electronic waste (e-waste) is a potential source of valuable and critical materials such as gold, silver, platinum group metals, copper, and rare earth elements. In Canada, however, less than 20% of generated e-waste is recycled. There exists a need for an efficient, sustainable e-waste metal recovery process that could be deployed on a regional scale to incentivize collection and recycling. In this paper, a process model was developed in MATLAB to simulate the electrochemical recovery of base and precious metals from printed circuit boards (PCBs) using regenerated Fe3+ oxidant. In the modelled process, Fe3+ ions are regenerated at the anode of an electrolytic cell while extracted metals are recovered on the cell cathode. A two-stage process using unique electrolyte solution for each allows base metals (Cu, Sn) and precious metals (Ag, Au, Pd) to be recovered separately. The process model was able to predict economic and environmental performance of the process given a set of feed conditions and operating parameters. Monte Carlo analysis and sensitivity analysis were used to determine key operating parameters and optimal setpoints for a final design. The final design was environmentally and economically feasible, with an estimated net annual profit of CA$ 321,000 after tax, and a carbon intensity 57.7% lower than the conventional pyrometallurgical process used for e-waste metal recovery. [ABSTRACT FROM AUTHOR]

Advances in urbanization and construction technology have made buildings increasingly larger and ostentatious. These large engineering structures that push the limits of engineering and technology, it is become more affected by natural events such as wind, temperature, earthquake etc. Therefore, the construction of such structures and subsequent determination of oscillation amplitudes and spectral characteristics have become an important issue needed. In the scope of this study; GNSS receivers, electronic inclinometer, weather station and total station and reflectors for ground observations are mounted on a tower (in 165 m heights). The data collected simultaneously using this measurements instruments were analyzed and the results were evaluated. It has been observed that the displacement changes obtained from different measuring instruments are compatible with each other and are sufficient to determine this dominant oscillation mode. The movement amplitude and spectral characteristics of the structure representing the structural movements at the time of measurement were examined. The results obtained from three different measuring instruments; showed that the structure is very rigid and makes a dominant movement with a period of 24 hours. This dominant movement of the tower, which lasted for a full day, has been explained by the effect of the temperature change caused by the effect of the sun. [ABSTRACT FROM AUTHOR]

The applications of e-government systems continue to attract the interests of both practitioners and researchers. Despite the extant literature on e-government adoption research, most of these studies have similar theories and predictors. Furthermore, many of these studies have presented e-government adoption predictors that are contradictory with each other or have inconsistent findings. The purpose of this study is to conduct a comprehensive review of existing e-government adoption research and find out the most frequently examined and best predictors of e-government adoption by users. Through the use of 75 relevant studies, we found that that service preference, perceived behavioral control, attitude, satisfaction and perceived usefulness are the best predictors of egovernment adoption. Based on these results, we suggest that future researchers should consider these predictors in e-government adoption. We also provided a comprehensive e-government adoption model as well as recommended research directions for future egovernment research. [ABSTRACT FROM AUTHOR]

10-(4,5-di-p-Tolyl-1H-1,2,3-triazol-1-yl)-2,3-dimethoxypyrido[1,2-a]indole 2 was obtained by interaction of 5,6-di-p-tolyl-3-(2-pyridyl)-1,2,4-triazine 1 with 4,5-dimethoxydehydrobenzene. The fluorescence properties of the compound 2 in the presence of nitroaromatic compounds were studied. [ABSTRACT FROM AUTHOR]