We investigate the behavior of the deflection of light rays by charged and rotating AdS black holes using the Gauss–Bonnet formalism. Taking weak field approximations and certain appropriate limits ...associated with AdS geometries, we compute and analyze such an optical quantity by varying the involved moduli space parameters. First, we study the charge and the AdS radius effects on the deflection angle of RN-AdS black holes. For small values of the impact parameter
b
, we find that the charge effect is relevant. Precisely, it decreases the deflection angle, while the AdS background one is not. For large values of
b
, however, these optical behaviors have been inverted and the deflection angle becomes an increasing function of the charge. In this way, the cosmological constant effect is remarked to be relevant showing linear variations of the deflection angle. Varying the charge, we find a critical impact parameter value
b
c
where the charge effect is inverted. For rotating solutions, we show that the spinning parameter still decreases the deflection angle without any changing behavior observed in the charge effect. Evincing of the cosmological constant, we recover known results corresponding to charged and rotating ordinary black hole solutions. Examining the plasma effect, we reveal that the deflection angle keeps the same behavior being a decreasing function in terms of the frequency ratio.
The wet granulation process is sensitive to changes in product properties and process variables. The optimal process and formulation are based on the knowledge of the granule growth mechanisms and of ...the effects of product properties and process variables. This paper presents the study of wet granulation of microcrystalline cellulose powder, MCC (Avicel PH101) using high-shear mixer granulator. It aims at understanding the effect of operating parameters (impeller rotational speed, liquid binder flow ate) and of physicochemical properties (viscosity, wettability) of a binder solution on solid particles surfaces, on the agglomeration kinetics. The experiments are carried out with water, aqueous solutions of sodium carboxymethylcellulose, polyvinylpyrrolidone, hydroxypropylméthylcellulose or a non ionic surfactant oxo-C
10C
6 at a critical micellar concentration.
Concerning the process variables the experimental results show that an optimal interval of impeller speed operation exists ranging from 150 to 200 rpm for granule growth. Below, an uncontrollable agglomerate size and localised over-wetting occur, and above granule breakage occurs. Increasing the liquid binder flow rate reduces the extension of the non growth regime, but does not affect the granule mean size.
The effect of the physicochemical properties is evaluated using a modified capillary viscous number,
Ca′, that we define as the ratio between the viscous forces (
μ
L
U) and the work of adhesion
W
a
=
γ
L(1
+
cos
θ). For
Ca′
<
1, the viscosity of the solution does not significantly affect the granulation process. The dominant forces in the granulation process are the interfacial forces since increasing the work of adhesion enhances the growth kinetics. For
Ca′
>
1.6, the viscous forces predominate and control the granule growth.
This paper presents the study of wet granulation of microcrystalline cellulose, MCC (Avicel PH101) powder using high shear mixer granulator. It aims at understanding the effect of operating parameters and of physicochemical properties of a binder solution on solid particle surfaces, on the agglomeration kinetics. The experiments are carried out with water and by aqueous solutions of polymers.
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Inspired by M-theory scenarios, we investigate optical properties of black holes in the Starobinsky–Bel–Robinsion gravity. Precisely, we study the shadows and the deflection angle of light rays by ...this class of black holes in such a novel gravity. First, we approach the shadows of the Schwarzschild-type solutions. As expected, we find perfect circular shadows where the size decreases with a stringy gravity parameter denoted by
β
. We reveal that this parameter is constrained by the shadow existence. Combining the Newman–Janis algorithm and the Hamilton–Jacobi mechanism, we examine the shadow behaviors of the rotating solutions in terms of one-dimensional real curves. Precisely, we obtain various sizes and shapes depending on the rotating parameter and the stringy gravity parameter
a
and
β
, respectively. To examine the shadow geometric deformations, we study the astronomical observables and the energy emission rate. As envisaged, we show that
a
and
β
have an impact on such shadow behaviors. For specific values of
a
, we remark that the obtained shadow shapes share certain similarities with the ones of the Kerr black holes in the plasma backgrounds. Using the Event Horizon Telescope observational data, we provide predictions for the stringy gravity parameter
β
which could play a relevant role in the M-theory compactifications. After that, we discuss the behaviors of the light rays near to such four dimensional black holes by calculating the deflection angle in terms of a required moduli space.
Bi0.8Ba0.1Er0.1Fe0.96Cr0.02Mn0.02O3 (BBEFCMO) multiferroic ceramic was synthesized through the sol-gel route. The impact of incorporating various dopants into both A and B sites of the BiFeO3 was ...investigated, and structural, Raman, dielectric, electric, and magnetic properties were studied. X-ray diffraction analysis and Raman spectroscopy revealed a rhombohedral structure with the R3c space group for the doped material (BBEFCMO). Dielectric properties were examined across a frequency range of 102–106 Hz. The present multiferroic material exhibits a colossal dielectric constant and minimal dielectric loss tangent, making it suitable for applications in energy storage. Furthermore, the Cole-Cole type of relaxation was deduced from the imaginary part of the modulus for both grain and boundary-grain contributions. Overall, this study indicates that substituting ions in both A and B sites of BiFeO3 significantly enhances its multiferroic properties, as evidenced by dielectric and magnetic measurements.
Recent developments have shown that coupling a Micromegas gaseous detector on a glass substrate with a transparent anode and a CMOS camera enables the optical readout of Micromegas detectors with a ...good spatial resolution, demonstrating that the glass Micromegas detector is well-suited for imaging. This feasibility test has been effectuated with low-energy X-ray photons also permitting energy resolved imaging. This test opens the way to different applications. Here we will focus on two applications. Namely, neutron imaging for non-destructive examination of highly gamma-ray emitting objects, such as irradiated nuclear fuel or radioactive waste. And secondly, we are developing a beta imager for the cell tagging in the field of anticancerous drug studies.
Both applications require to design the detectors in view of the specific constraints of reactor dismantling and medical applications: spatial resolution and strong gamma suppression for neutron imaging and precise rate and energy spectrum measurements for the beta.
A dedicated system consisting of a glass Micromegas detector and an ultrasensitive camera has been designed and assembled. Here we present the first results from the characterization of the detectors, as well as the first acquired images.
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