The kurtosis parametric characterization of the passage of a standard Hermite–Gaussian beam and an elegant Hermite–Gaussian beam through a fractional Fourier transformation system with a spherically aberrated lens

The propagation characteristics of the kurtosis parameters of a standard Hermite–Gaussian (SHG) beam and of an elegant Hermite–Gaussian (EHG) beam, each passing through a fractional Fourier transformation (FRFT) system with a spherically aberrated lens, are studied in detail. Some numerical calculations are made by introducing an efficient algorithm, based on the Collins diffraction integral formula. The resulting graphs illustrate the striking difference between ideal FRFT systems and those with a spherically aberrated lens. The kurtosis parameters of both SHG and EHG beams passing through a type I Lohmann system with a spherically aberrated lens are seen to change with the fractional order periodically and the fundamental period is 4, but for type II the fundamental period is 2. Different values of spherical aberration coefficients affect the kurtosis parameters in greatly different ways. The values of the kurtosis parameters of a SHG beam passing through either type of Lohmann system with a spherically aberrated lens are no longer equal to those of an EHG beam, even when they have the same fractional orders and the same spherical aberration coefficients.     

Focal switch and dual focal switch of a Hermite–Gaussian beam illuminating a lens and sinusoidal amplitude grating separated system

Based on the Collins formula, analytical representation of a Hermite–Gaussian beam propagating through a lens and sinusoidal amplitude grating separated system is obtained. Focal shift occurring in such a system is studied in detail with numerical calculation examples. It is found that the focal switch and the dual focal switch can emerge depending not only on the effective Fresnel number, but also on the uniform transmittance amplitude and the spatial frequency of the grating and beam parameter of the illumination Hermite–Gaussian beam.     

Disturbance propagation and design of power flow reduction in a cross‐type truss beam

Abstract

There are four passing bands in an infinite truss beam. For an incident bending wave from any branch of a cross‐type structure encountering the conjunction of these four branches of this structure, the induced wave modes in each branch can be predicted by using their dispersion of passing bands. The energy carried by this incident bending wave will be redistributed into these branches by the induced wave modes. The total energy value is conservative. Enlarging the cross‐sectional area or stiffening the material of horizontal members of all dissimilar cells around the outlets of this conjunction substructure enhances the power reduction in the two branches perpendicular to the incident direction. On the other hand, the induced power flow in the branch whose direction is the same as the incident direction can be reduced by stiffening the cross‐sectional area or stiffening the material of diagonal members of these three cells.     

Modeling of Processes of the Formation and Transformations of Nanoclusters in a Rapidly‐Cooling Mixture of a Vapor and an Inert Gas

Abstract

As the initial state, we consider a high‐temperature vapor consisting of atoms (or a mixture of atoms and small clusters). It is assumed that during a rapid expansion of the vapor and its mixing with a buffer gas (e.g., helium), it cools down to the temperature when the dissociation of clusters run slowly, while the processes of nucleation (association) of particles dominate. Such approach was employed, e.g., for modeling of processes of formation of carbon nanoclusters (CNC) in a carbon arc.     

Ethics as an enabler and a constraint – Narratives on technology development and artificial intelligence in military affairs through the case of Project Maven

Project Maven is an AI-induced information technology for military applications initiated by the United States Department of Defence (DoD) in 2017 and originally signed on to a civilian contractor, namely Google. However, this initiative raised massive resistance from a substantial amount of Google employees, eventually leading to the contract's annulation. This article uses narrative analysis to investigate enabling and constraining arguments of AI for military purposes that appeared in the debate following the public announcement of Project Maven. In addition, the article highlights the co-production of ethics, technology, and the complex issues that arise from civilian-military exchanges in technology development. Enabling arguments associated with consequentialist ethics are identified as narratives of accuracy and maintenance. Accuracy constitutes a guiding principle for saving civilian lives, while maintenance is directed at keeping the power balance intact. In contrast, constraining arguments proceed from deontological ethics that emphasize disengagement and ambivalence. Disengagement amplifies a civilian/military divide, while ambivalence exhibits conflicting views concerning the prospect of supplementing technological solutions that have the potential to contribute to war and civilian casualties. Conclusively, security narratives and technological storytelling are important aspects to consider since they hold a performative function that influences the framing and mobilization of security and technology development.     

Effort-reward imbalance at work and driving anger in an Australian community sample: is there a link between work stress and road rage?

Both workplace stress and road rage are reported to be on the increase. This study examined the effort–reward imbalance (ERI) model of work stress and its relationship with general anger and driving anger in a community sample of 130 Australian workers. It also examined international differences in driving anger, with Australian motorists reporting lower levels of driving anger than American motorists but higher levels than British motorists. Hierarchical multiple regressions confirmed ERI increased driving anger via the mediating variables of general anger and overcommitment; individuals suffering ERI may develop increased general anger or overcommitment, in turn increasing propensity to experience driving anger. Regressions also showed that overcommitment (but not general anger) moderated the effect of ERI on driving anger; ERI has a greater influence on increasing driving anger in individuals with high overcommitment at work. The results have considerable implications for the safety and emotional health of individuals who perceive an imbalance between their efforts and rewards at work, and overcommitted individuals may be at greater risk. The wider implications of the relationship between work stress, emotional well-being and driving anger in employees, along with the potential of driver education interventions, are discussed as public health issues.     

Study on the interaction between a dislocation and impurities in KCl:Sr<Superscript>2+</Superscript> single crystals by the Blaha effect—Part IV influence of heat treatment on dislocation density

Strain-rate cycling tests associated with ultrasonic oscillation were carried out at 80–239 K for two kinds of KCl:Sr²⁺ (0.05 mol.% in the melt) single crystals: one is a quenched specimen and the other an annealed one. In this study, it was found that the density of moving dislocation is not influenced by the heat treatment. Furthermore, the increase in forest dislocation density for the annealed specimen seemed to be remarkable under the compression test, compared with that for the quenched specimen. As a result, the strain-hardening rate increased and the extent of plastic deformation region became short at a given temperature by annealing the quenched specimens. The investigation concerning forest dislocation density was conducted on the basis of the which will represent the variation of the strain-rate sensitivity due to dislocation cuttings with shear strain.