A stochastic model of the influence of buffer gas collisions on Mollow spectra

In this paper we consider the influence of collisional fluctuations on the Mollow spectra of resonance fluorescence (RF). The fluctuations are taken into account by a simple shift of the constant detuning, involved in a set of optical Bloch equations by collision frequency noise which is modelled by a two-step random telegraph signal (RTS). We consider in detail the Mollow spectra for RF in the case of an arbitrary detuning of the laser frequency, where the emitter is a member of a statistical ensemble in thermodynamic equilibrium with the buffer gas at temperature $T$ which is treated as a colored environment, and velocity $v$ is distributed with the Maxwell-Boltzmann density

Entrainment and thrust augmentation in pulsatile ejector flows

This study comprised direct thrust measurements, flow visualization by use of a spark shadowgraph technique, and mean and fluctuating velocity measurements with a pitot tube and linearized constant temperature hot-wire anemometry respectively. A gain in thrust of as much as 10 to 15% was observed for the pulsatile ejector flow as compared to the steady flow configuration. From the velocity profile measurements, it is concluded that this enhanced augmentation for pulsatile flow as compared to a nonpulsatile one was accomplished by a corresponding increased entrainment by the primary jet flow. It is also concluded that the augmentation and total entrainment by a constant area ejector critically depends upon the inlet geometry of the ejector. Experiments were performed to evaluate the influence of primary jet to ejector area ratio, ejector length, and presence of a diffuser on pulsatile ejector performance

A refined sin hyperbolic shear deformation theory for sandwich FG plates by enhanced meshfree with new correlation function

The moving Kriging interpolation-based (MKI) meshfree method is extended to mechanical behavior analysis of isotropic and sandwich functionally graded material plates. The MKI meshfree method, which is free of shear correction factors effect in plate analysis, is further enhanced by introducing a new multi-quadric correlation function, eliminating drawbacks of its conventional form, gaining accurate solution. In this paper, a new refined sin hyperbolic shear deformation plate theory (N-RSHSDT) is introduced for plate kinematics. The present theory gives rise to four governing equations only, and achieves the sin hyperbolic distribution of the transverse shear strains through the plate thickness. To show the accuracy and effectiveness of the developed method, numerical experiments are performed for both isotropic and sandwich composite plates

Wafer scale texturing of LiNbO3

We report a novel technique for micro texturing of LiNbO<sub>3</sub>. Well-defined raised ridges and etched trenches are demonstrated. This technique is suitable for the realization of surface relief gratings and photonic crystals

Environmental contamination with clostridioides (Clostridium) difficile in Vietnam

AIMS: To investigate the prevalence, molecular type, and antimicrobial susceptibility of Clostridioides difficile in the environment in Vietnam, where little is known about C. difficile. METHODS AND RESULTS: Samples of pig faeces, soils from pig farms, potatoes, and the hospital environment were cultured for C. difficile. Isolates were identified and typed by polymerase chain reaction (PCR) ribotyping. The overall prevalence of C. difficile contamination was 24.5% (68/278). Clostridioides difficile was detected mainly in soils from pig farms and hospital soils, with 70%-100% prevalence. Clostridioides difficile was isolated from 3.4% of pig faecal samples and 5% of potato surfaces. The four most prevalent ribotypes (RTs) were RTs 001, 009, 038, and QX574. All isolates were susceptible to metronidazole, fidaxomicin, vancomycin, and amoxicillin/clavulanate, while resistance to erythromycin, tetracycline, and moxifloxacin was common in toxigenic strains. Clostridioides difficile RTs 001A+B+CDT- and 038A-B-CDT- were predominantly multidrug resistant. CONCLUSIONS: Environmental sources of C. difficile are important to consider in the epidemiology of C. difficile infection in Vietnam, however, contaminated soils are likely to be the most important source of C. difficile. This poses additional challenges to controlling infections in healthcare settings

Mechanical Attributes of Fractal Dragons

Fractals are ubiquitous natural emergences that have gained increased attention in engineering applications, thanks to recent technological advancements enabling the fabrication of structures spanning across many spatial scales. We show how the geometries of fractals can be exploited to determine their important mechanical properties, such as the first and second moments, which physically correspond to the center of mass and the moment of inertia, using a family of complex fractals known as the dragons

Etching of lithium niobate using standard Ti indiffusion technique

We present evidence of etching LiNbO3 when annealing two wafers in contact with an intermediate Ti strip. Etched features are characterized qualitatively using atomic force microscopy. The impact of the Ti strip thickness on the depth and roughness of the etched surface is quantified. Etched trenches of similar depths to the original Ti film are achieved with very smooth etched surface