RF and microwave diagnostics for compact plasma traps and possible perspectives for fusion devices

Plasma diagnostics is a topic having a great impact on R&D in compact ion sources as well as in large fusion reactors. Towards this aim, non-invasive microwave diagnostics approaches, such as interferometric, polarimetric and microwave imaging profilometric techniques can allow obtaining volumetric, line-integrated or even space-resolved information about plasma electron density. Special probes can be also designed and implemented in order to characterize external and/or self-generated radio-waves in the plasmas. In particular, the design, construction and operation of a K-band microwave interferometry/polarimetry setup based on the Frequency-Modulated Continuous-Wave (FMCW) method at INFN-LNS will be described: this tool provides reliable measurements of the plasma density even in the extreme unfavorable wavelength-to-plasma scale ratio in plasma-based ion sources. A “frequency sweep” and a post-processing filtering method (for interferometry and polarimetry, respectively) were used to filter out the multipath contributions or cavity induced depolarizations in the detected signals. Besides this, the use of the aforementioned RF plasma-immersed probes will also be discussed, which allow measuring local E-fields and fast temporal response in order to characterize turbulent (through kinetic instabilities, cyclotron maser emission, etc.) vs. stable plasma regimes. An analysis based on wavelet transform applied to measurements of plasma radio self-emission in B-minimum and simple mirror traps will be presented. These tools and methods have the potential to be applied to plasma machines both in compact traps and large-size reactors with a proper scaling.

Cavity quantum-electrodynamical time-dependent density functional theory within Gaussian atomic basis. II. Analytic energy gradient

Following the formulation of cavity quantum electrodynamical time-dependent density functional theory (cQED-TDDFT) models [Flick et al., ACS Photonics 6, 2757-2778 (2019); Yang et al., J. Chem. Phys. 155, 064107 (2021)], here we report the derivation and implementation of the analytic energy gradient for the polaritonic states of a single photochrome within the cQED-TDDFT models. Such gradient evaluation is also applicable to a complex of explicitly-specified photochromes, or, with proper scaling, a set of parallel-oriented, identical-geometry, non-interacting molecules in the microcavity.

Statistical properties of a stochastic model of eddy hopping

Statistical properties are investigated for the stochastic model of eddy hopping, which is a novel cloud microphysical model that accounts for the effect of the supersaturation fluctuation at unresolved scales on the growth of cloud droplets and on spectral broadening. Two versions of the model, the original version by Grabowski and Abade (2017) and the second version by Abade et al. (2018), are considered and validated against the reference data taken from direct numerical simulations and large-eddy simulations (LESs). It is shown that the original version fails to reproduce a proper scaling for a certain range of parameters, resulting in a deviation of the model prediction from the reference data, while the second version successfully reproduces the proper scaling. In addition, a possible simplification of the model is discussed, which reduces the number of model variables while keeping the statistical properties almost unchanged in the typical parameter range for the model implementation in the LES Lagrangian cloud model.

Numerical Study on Tip Vortex Cavitation Inception on a Foil

In this paper, the inception of tip vortex cavitation in weak water has been predicted using a numerical simulation, and a new scaling concept with variable exponent has also been suggested for cavitation inception index. The numerical simulations of the cavitating flows over an elliptic planform hydrofoil were performed by using the RANS approach with a Eulerian cavitation model. To ensure the accuracy of the present simulations, the effects of the turbulence model and grid resolution on the tip vortex flows were investigated. The turbulence models behaved differently in the boundary layer of the tip region where the tip vortex is developed, which resulted in different pressure and velocity fields in the vortex region. Furthermore, the Reynolds stress model for the finest grid showed a better agreement with the experimental data. The tip vortex cavitation inception numbers for the foil, predicted by using both wetted and cavitating flow simulation approaches, were compared with the measured cavitation index values, showing a good correlation. The current cavitation scaling study also suggested new empirical relations as a function of the Reynolds number substitutable for the two classic constant scaling exponents. This scaling concept showed how the scaling law changes with the Reynolds number and provided a proper scaling value for any given Reynolds numbers under turbulent flow conditions.

Statistical properties of a stochastic model of eddy hopping

Statistical properties are investigated for the stochastic model of eddy hopping, which is a novel cloud microphysical model that accounts for the effect of the supersaturation fluctuation at unresolved scales on the growth of cloud droplets and on spectral broadening. It is shown that the model fails to reproduce a proper scaling for a certain range of parameters, resulting in a deviation of the model prediction from the reference data taken from direct numerical simulations and large-eddy simulations (LESs). Corrections to the model are introduced so that the corrected model can accurately reproduce the reference data with the proper scaling. In addition, a possible simplification of the model is discussed, which may contribute to a reduction in computational cost while keeping the statistical properties almost unchanged in the typical parameter range for the model implementation in the LES Lagrangian cloud model.

ASSESSMENT AND MANAGEMENT OF SAFETY RISKS THROUGH HIERARCHICAL ANALYSIS IN FUZZY SETS TYPE 1 AND TYPE 2: A CASE STUDY (FARYAB CHROMITE UNDERGROUND MINES)

There is a high rate of casualty among miners in the world every year. One way to reduce accidents and increase safety in mines is to use the risk management process to identify and respond to major hazards in mines. The present study is an attempt to investigate the assessment and management of safety risks in Faryab chromite underground mines. In this paper, the method of AHP in type-1 and type-2 fuzzy sets is used for risk assessment. Upon studying two underground mines of Faryab chromite (Makran and Nemat), 45 hazards were divided into 9 groups, among which 7 main risks were eventually identified. The risk assessment showed that the most important hazards in the Nemat underground mine are the required airflow, the lack of proper scaling and post-blast scaling. Similarly, the assessment of hazards in the Makran underground mine showed that post-blast scaling, absence of proper scaling, and proper ventilation of dust, are the most important hazards. Finally, after detecting the causes of the accidents, based on the records of accidents at the mine safety, health, and environmental unit, technical personnel’s descriptions, and similar risk projects, proper responses are prepared for each group of hazards.

A Comparative Study on Applying Bio-Inspired Optimization Techniques for Designing an Effective Fuzzy Logic Controller

A fuzzy logic – based controller has been considered to be a feasible and effective control strategy for a numerous number of complex control problems. To design such an effective fuzzy logic controller, it is necessary to determine proper scaling factors which significantly affect the control quality of the system. This study concentrates on applying well-known bio-inspired optimization methods, i.e. PSO, GA and DE, to deal with this determination. A typical PD-type fuzzy logic architecture is chosen to be a traditionally intelligent controller. Then, the bio-inspired optimization methods will be applied for such a fuzzy logic controller to optimally determine its three scaling factors. The simulation results provided for the load – frequency control issue of a two-area interconnected hydropower system verifies the applicability of the proposed control strategy. Comparative simulations are also to decide which is the best choice of the bio-inspired optimization methods in the determination of significant scaling factors regarding the PD-type fuzzy logic controller.

Comparison between Communicated and Calculated Exposure Estimates Obtained through Three Modeling Tools

This study aims to evaluate the risk assessment approach of the REACH legislation in industrial chemical departments with a focus on the use of three models to calculate exposures, and discuss those factors that can determine a bias between the estimated exposure (and therefore the expected risk) in the extended safety data sheets (e-SDS) and the expected exposure for the actual scenario. To purse this goal, the exposure estimates and risk characterization ratios (RCRs) of registered exposure scenarios (ES; “communicated exposure” and “communicated RCR”) were compared with the exposure estimates and the corresponding RCRs calculated for the actual, observed ES, using recommended tools for the evaluation of exposure assessment and in particular the following tools: (i) the European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment v.3.1 (ECETOC TRA), (ii) STOFFENMANAGER® v.8.0 and (iii) the Advanced REACH Tool (ART). We evaluated 49 scenarios in three companies handling chemicals. Risk characterization ratios (RCRs) were calculated by dividing estimated exposures by derived no-effect levels (DNELs). Although the calculated exposure and RCRs generally were lower than communicated, the correlation between communicated and calculated exposures and RCRs was generally poor, indicating that the generic registered scenarios do not reflect actual working, exposure and risk conditions. Further, some observed scenarios resulted in calculated exposure values and RCR higher than those communicated through chemicals’ e-SDSs; thus ‘false safe’ scenarios (calculated RCRs > 1) were also observed. Overall, the obtained evidences contribute to doubt about whether the risk assessment should be performed using generic (communicated by suppliers) ES with insufficient detail of the specific scenario at all companies. Contrariwise, evidences suggested that it would be safer for downstream users to perform scenario-specific evaluations, by means of proper scaling approach, to achieve more representative estimates of chemical risk.

ON SEVERAL PROPERTIES OF A CLASS OF PREFERENTIAL ATTACHMENT TREES—PLANE-ORIENTED RECURSIVE TREES

In this paper, several properties of a class of trees presenting preferential attachment phenomenon—plane-oriented recursive trees (PORTs) are uncovered. Specifically, we investigate the degree profile of a PORT by determining the exact probability mass function of the degree of a node with a fixed label. We compute the expectation and the variance of degree variable via a Pólya urn approach. In addition, we study a topological index, Zagreb index, of this class of trees. We calculate the exact first two moments of the Zagreb index (of PORTs) by using recurrence methods. Lastly, we determine the limiting degree distribution in PORTs that grow in continuous time, where the embedding is done in a Poissonization framework. We show that it is exponential after proper scaling.

Inverse of K Regular Super Fuzzy Matrix

Fuzzy matrix (FM) is a rich topic in modeling uncertain situation occurred. Every FM can be visualized as a three dimensional figure, but this representation is not possible for classical matrix without any proper scaling. To overcome this problem we need a certain special classical fuzzy matrix. In this paper, the concept of inverse of k-regular fuzzy matrix is introduced and derived some basic properties of an inverse of k-regular fuzzy matrix. This leads to the characterization of a matrix for which the regularity indicator is equal. Further the connection between regular, k-regular and consistency of powers of fuzzy matrices are discussed.