Generalized D-Symmetric Operators I

2000 Mathematics Subject Classification: Primary: 47B47, 47B10; secondary 47A30.Let H be an infinite-dimensional complex Hilbert space and let A, B ∈ L(H), where L(H) is the algebra of operators on H into itself. Let δAB: L(H) → L(H) denote the generalized derivation δAB(X) = AX − XB. This note will initiate a study on the class of pairs (A,B) such that [‾(R(δAB))] = [‾(R(δB*A*))]; i.e. [‾(R(δAB))] is self-adjoint

Model-independent study for a quintessence model of dark energy: Analysis and Observational constraints

In this paper, a well-motivated parametrization of the Hubble parameter ($H$% ) is revisited that renders two models of dark energy showing some intriguing features of the late-time accelerating Universe. A general quintessence field is considered as a source of dark energy. We have obtained tighter constraints using recently updated cosmic observational datasets for the considered models. The two models described here show a nice fit to the considered uncorrelated Hubble datasets, Standard candles, Gamma Ray Bursts, Quasars, and uncorrelated Baryonic Acoustic Oscillations datasets. Using the constrained values of the model parameters, we have discussed some features of the late-time accelerating models and obtained the present value of the deceleration parameter ($q_{0}$), the present value of the Hubble parameter ($H_{0}$) and the transition redshift ($z_{t}$) from deceleration to acceleration. The current value of the deceleration parameter for both models is consistent with the Planck 2018 results. The evolution of the geometrical and physical parameters is discussed through graphical representations for both models with some diagnostic analysis. The statistical analysis performed here shows greater results and overall, the outcomes of this investigation are superior to those previously found.Comment: 22 pages, 26 figure

Observational Constraints and Cosmological Implications of Scalar-Tensor f(R,T)f(R, T) Gravity

Recently, the scalar-tensor representation of $f (R,T)$ gravity was used to explore gravitationally induced particle production/annihilation. Using the framework of irreversible thermodynamics of open systems in the presence of matter creation/annihilation, the physical and cosmological consequences of this setup were investigated in detail. In this paper, we test observationally the scalar-tensor representation of $f(R,T)$ gravity in the context of the aforementioned framework, using the Hubble and Pantheon+ measurements. The best fit parameters are obtained by solving numerically the modified Friedmann equations of two distinct cosmological models in scalar tensor $f(R, T)$ gravity, corresponding to two different choices of the potential, and by performing a Markov Chain Monte Carlo analysis. The best parameters are used to compute the cosmographic parameters, i.e., the deceleration, the jerk and the snap parameters. Using the output resulting from the Markov Chain Monte Carlo analysis, the cosmological evolution of the creation pressure and of the matter creation rates are presented for both models. To figure out the statistical significance of the studied scalar-tensor $f(R,T)$ gravity, the Bayesian and the corrected Akaike information criteria are used. The latter indicates that the first considered model in scalar tensor $f(R,T)$ gravity is statistically better than $\Lambda$CDM, i.e., it is more favored by observations. Besides, a continuous particle creation process is present in Model 1. On the other hand, for large redshifts, in Model 2 the particle creation rate may become negative, thus indicating the presence of particle annihilation processes. However, both models lead to an accelerating expansion of the Universe at late times, with a deceleration parameter equivalent to that of the $\Lambda$CDM model.Comment: 17 pages, 14 figures; accepted for publication in MNRA

InSAR as a tool for monitoring hydropower projects: A review

This paper provides a review of using Interferometric Synthetic Aperture Radar (InSAR), a microwave remote sensing technique, for deformation monitoring of hydroelectric power projects, a critical infrastructure that requires consistent and reliable monitoring. Almost all major dams around the world were built for the generation of hydropower. InSAR can enhance dam safety by providing timely settlement measurements at high spatial-resolution. This paper provides a holistic view of different InSAR deformation monitoring techniques such as Differential Synthetic Aperture Radar Interferometry (DInSAR), Ground-Based Synthetic Aperture Radar (GBInSAR), Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR), Multi-Temporal Interferometric Synthetic Aperture Radar (MTInSAR), Quasi-Persistent Scatterer Interferometric Synthetic Aperture Radar (QPSInSAR) and Small BAseline Subset (SBAS). PSInSAR, GBInSAR, MTInSAR, and DInSAR techniques were quite commonly used for deformation studies. These studies demonstrate the advantage of InSAR-based techniques over other conventional methods, which are laborious, costly, and sometimes unachievable. InSAR technology is also favoured for its capability to provide monitoring data at all times of day or night, in all-weather conditions, and particularly for wide areas with mm-scale precision. However, the method also has some disadvantages, such as the maximum deformation rate that can be monitored, and the location for monitoring cannot be dictated. Through this review, we aim to popularize InSAR technology to monitor the deformation of dams, which can also be used as an early warning method to prevent any unprecedented catastrophe. This study also discusses some case studies from southern India to demonstrate the capabilities of InSAR to indirectly monitor dam health

Evaporation of Electrolyte During SVET Measurements: The Scale of the Problem and the Solutions

The objective of this work is to investigate the scale of the effect of spontaneous solution evaporation during SVET (Scanning Vibrating Electrode Technique) measurements and demonstrate how it biases the final results. When SVET maps are continuously acquired for more than several hours, the measured currents are smaller than expected. This is attributed to solvent (typically water) evaporation which leads to an increase in solution conductivity over time. If this is not considered when converting the measured potential differences into the local current densities, the SVET results display currents smaller than the true ones. Here, this effect is studied with a platinum disk electrode as source of a constant current and a model corroding system consisting of the AA2024/CFRP galvanic couple. Corrective actions are proposed to mitigate the problem, either in the experimental set‐up or as numerical correction

Abces amibien cerebral: a propos de trois cas avec revue de la litterature

Introduction L’abcès amibien cérébral est une infection rare mais mortelle. Depuis son identification en 1965, peu de cas ont été observés dans le monde entier.Matériel et méthode Les objectifs de cette étude étaient de caractériser les aspects cliniques, radiologiques, histologique, pronostic ainsi que thérapeutique de cette pathologie avec une revue de la littérature. Nous rapportons trois cas d’abcès amibien cérébral qui ont été admis dans notre service entre 2010 et 2013.Résultats Il s’agit de deux hommes et une femme, âgés respectivement de 33, 43 et 56 ans qui ont été opérés. Le diagnostic a été confirmé par les examens histologique et sérologique. Nous n’avons observé aucune mortalité.Conclusion Il s’agit d’une atteinte sporadique mais représente un problème de santé publique et dont le pronostic est habituellement sombre.Mots clés : amibiase; abcès cérébral; IRM ; TDM; examen histologiqu

Isolation, synthesis and optimization of cyclopropanation process of 4-allyl-2-methoxyphenol

The synthesis of 4-((2,2-dichlorocyclopropyl)methyl)-2-methoxyphenol 2 have been accomplished by using cyclopropanation process and Reponse Surface Methodology [1,2]. This methodology was used to determine the optimal conditions for the cyclopropanation reaction of eugenol 1. The reaction time (X1) and the ratio of the reaction mixture’s solvent (X2) were the two investigated factors. The statistical analysis of this study indicates that both of these factors had significant effects on the cyclopropanation yield. The central composite design showed that polynomial regression models were in good agreement with the experimental results of the coefficient determination (0.95) of product 2 yield. The optimal conditions were 17.44 and 5.78 hours. In such condition, the predicted yield of the product 2 was 43.96%. Keywords: Eugenol; 4-((2,2-dichlorocyclopropyl)methyl)-2-methoxyphenol; Central composite design; Optimization experiment

The Role of Cu-Based Intermetallic on the Direct Growth of a ZnAl LDH Film on AA2024

The direct ZnAl layered double hydroxide growth on AA2024 is a fast-occurring reaction, yet is characterized by an inhomogeneous film thickness. It has been shown that at the periphery of Cu-rich intermetallic, the flakes tend to be larger and denser. A combination of in situ and ex situ measurements were used to monitor the changes in the layered double hydroxide film grown on the regions of intermetallics. Immediately after immersion, an activation of the intermetallic phases is observed due to the dealloying process with an almost immediate film growth. Dealloying is followed by trenching of the adjacent Al matrix leading to an excessive production of large and dense layered double hydroxide flakes at the periphery of the intermetallic. However, the scanning electron microscopy cross-section images revealed that the trenching process leads to defects in the area surrounding the intermetallic. This could weaken the corrosion resistance performance of the layered double hydroxide conversion coating and lead to adhesion failure of consecutive polymer coatings. Nevertheless, this work highlights a few advantages and drawbacks of the layered double hydroxide conversion coatings and pathways to its potential optimization and improvement

A Logical Verification Methodology for Service-Oriented Computing

We introduce a logical verification methodology for checking behavioural properties of service-oriented computing systems. Service properties are described by means of SocL, a branching-time temporal logic that we have specifically designed to express in an effective way distinctive aspects of services, such as, e.g., acceptance of a request, provision of a response, and correlation among service requests and responses. Our approach allows service properties to be expressed in such a way that they can be independent of service domains and specifications. We show an instantiation of our general methodology that uses the formal language COWS to conveniently specify services and the expressly developed software tool CMC to assist the user in the task of verifying SocL formulae over service specifications. We demonstrate feasibility and effectiveness of our methodology by means of the specification and the analysis of a case study in the automotive domain