The Galactic transient black hole candidate (BHC) MAXI J1659−152 exhibited temporal and spectral evolution during its very first X-ray outburst (2010) after its discovery on 2010 September 25. Our ...recent studies of a few transient BHCs, including MAXI J1659−152, using the Chakrabarti–Titarchuk two-component advective flow (TCAF) solution as an additive table local model in the xspec software revealed details of the accretion-flow dynamics around the black holes. The TCAF model-fitted normalization (N) comes out to be almost constant throughout the entire outburst, consisting of several spectral states. We introduce two independent methods to determine the mass (M
BH) of the BHC: namely (i) keeping the TCAF fitted normalization parameter in a narrow range and (ii) studying the evolution of the quasi-periodic oscillation frequency (νQPO) with time, fitting with the propagating oscillatory shock (POS) model. The predicted mass ranges of the source with these two methods are 4.7–7.8 M⊙ and 5.1–7.4 M⊙, respectively. Combining the results of these two methods, we obtain a most probable mass range of the source of 4.7–7.8 M⊙ or
$6^{+1.8}_{-1.3}\,\mathrm{M}_{{\odot }}$
.
Over the past years, a growing body of work has linked numerous pervasive environmental chemicals with a multitude of adverse reproductive, developmental, behavioral, and metabolic changes in humans ...and animal models. Plasticizers include a wide variety of phthalate esters that are extensively used in a host of personal day care and cosmetic products. Many population-based studies have indicated a close association between diethyl phthalate (DEP) and diabetes albeit the mechanisms remain much unexplored. Presently, we report that long-term dietary administration of DEP to adult male Swiss albino mice at two different concentrations mirroring the recommended tolerable doses, severely impaired insulin signaling in hepatocytes and adipocytes. This was concomitant with sustained oxidative stress from the overactivation of NADPH oxidase 2, a major intracellular source of reactive oxygen species, in both the cell types. The present study provides evidences of the onset of insulin resistance in mice after chronic exposure to DEP in diet even at lower levels. This, in turn, can have serious pathological consequences with ultimate manifestations of type 2 diabetes and metabolic syndrome (MetS). Thus, by disrupting the central metabolic function of liver and adipose tissue, the key insulin target tissues, daily exposure to phthalates in plastics can potentially contribute to the alarming prevalence of MetS in recent times.
In this paper, we will review both past and recent progresses in the generation, detection and application of intense terahertz (THz) radiation. We will restrict the review to laser based intense ...few-cycle THz sources, and thus will not include sources such as synchrotron-based or narrowband sources. We will first review the various methods used for generating intense THz radiation, including photoconductive antennas (PCAs), optical rectification sources (especially the tilted-pulse-front lithium niobate source and the DAST source, but also those using other crystals), air plasma THz sources and relativistic laser-plasma sources. Next, we will give a brief introduction on the common methods for coherent THz detection techniques (namely the PCA technique and the electro-optic sampling), and point out the limitations of these techniques for measuring intense THz radiation. We will then review three techniques that are highly suited for detecting intense THz radiation, namely the air breakdown coherent detection technique, various single-shot THz detection techniques, and the spectral-domain interferometry technique. Finally, we will give an overview of the various applications that have been made possible with such intense THz sources, including nonlinear THz spectroscopy of condensed matter (optical-pump THz-probe, THz-pump THz-probe, THz-pump optical-probe), nonlinear THz optics, resonant and non-resonant control of material (such as switching of superconductivity, magnetic and polarization switching) and controlling the nonlinear response of metamaterials. We will also provide a short perspective on the future of intense THz sources and their applications.
Carbon capture and storage employing oxy-fuel combustion is one of the most promising options to reduce greenhouse gas emission. For the transition from conventional air-fired combustion to oxy-fuel ...combustion, there is a necessity of detailed investigation of various phenomena that occur during oxy-fuel combustion. Numerical modeling of oxy-fuel combustion process can serve the purpose effectively and efficiently. The current paper presents a thorough numerical investigation of the combustion process of pulverized coal under oxy-fuel conditions. The influence of inlet temperature and pressure of feed gas is investigated in the present study. Computational fluid dynamics simulation is performed for the test facility located at the Institute of Heat and Mass Transfer at Aachen University. The numerical results obtained employing various Reynolds Averaged Navier Stokes (RANS) models have been compared with measured data. The results showed that the strength and axial dispersion of the internal recirculation zone (IRZ) are enhanced at higher inlet temperature. The combustion of volatile matter present in coal shifts near the burner which results in shorter flames at higher inlet temperature. The flame temperature increased by ~9% with increase in inlet feed gas temperature from 313 to 800 K. Inlet feed gas pressure of 10.0 bar has ~38% increment and ~32% reduction in IRZ length and flame length, respectively, than the base case.
In high-order harmonic generation, resonant harmonics (RH) are sources of intense, coherent extreme-ultraviolet radiation. However, intensity enhancement of RH only occurs for a single harmonic ...order, making it challenging to generate short attosecond pulses. Moreover, the mechanism involved behind such RH was circumstantial, because of the lack of direct experimental proofs. Here, we demonstrate the exact quantum paths that electron follows for RH generation using tin, showing that it involves not only the autoionizing state, but also a harmonic generation from dressed-AIS that appears as two coherent satellite harmonics at frequencies ±2Ω from the RH (Ω represents laser frequency). Our observations of harmonic emission from dressed states open the possibilities of generating intense and broadband attosecond pulses, thus contributing to future applications in attosecond science, as well as the perspective of studying the femtosecond and attosecond dynamics of autoionizing states.
Sagnac interference experiment is theoretically analyzed in the curved spacetime of the Rotating Acoustic Black hole metric. The Zero and the infinite Sagnac delay has been analyzed. The geodesic ...motion in the metric is discussed very briefly to derive the formula for the Sagnac delay. For the first time, the values of the two constant parameters related to the metric of the acoustic black hole have been found to be restricted within certain limit by the use of the formula for the Sagnac delay. The equation for finding the sonic horizon has also been deduced.
This paper presents two mathematical models representing imprecise capacitated fixed-charge transportation problems for a two-stage supply chain network in Gaussian fuzzy type-2 environment. It is a ...two-stage transportation process from a manufacturing center to m potential distribution centers (DCs) and then from DCs to business centers of n retailers with particular demands. Retailers are situated at some distances apart. Here unit transportation costs, fixed charges, availabilities, and demands are imprecise and represented by Gaussian type-2 fuzzy numbers. The proposed models are formulated as profit maximization problems in such a way that some DCs are selected in order to satisfy the demands at all retailers. The type-2 fuzziness has been removed by using generalized credibility measure developed with the help of CV-based reduction method and hence the models are reduced to chance constrained programming problems with different credibility labels. The deterministic models are then solved using both genetic algorithm (GA) based on Roulette wheel selection, arithmetic crossover with uniform mutation and modified particle swarm optimization (PSO), where the position of each particle is adjusted according to its own experience and that of its neighbors. Finally models are illustrated with some numerical data. Some sensitivity analyses on the proposed models are presented.
Human walking influences indoor air quality mainly by resuspending dust particles settled on the floor. This study characterized walking‐induced particle resuspension as a function of flooring type, ...relative humidity (RH), surface dust loading, and particle size using a consistent resuspension mechanism. Five types of flooring, including hardwood, vinyl, high‐density cut pile carpet, low‐density cut pile carpet, and high‐density loop carpet, were tested with two levels of RH (40% and 70%) and surface dust loading (2 and 8 g/m2), respectively. Resuspension fraction ra (fraction of surface dust resuspended per step) for house dust was found to be varied from 10−7 to 10−4 (particle size: 0.4–10 µm). Results showed that for particles at 0.4–3.0 µm, the difference in resuspension fraction between carpets and hard floorings was not significant. For particles at 3.0–10.0 µm, carpets exhibited higher resuspension fractions compared with hard floorings. Increased RH level enhanced resuspension on high‐density cut pile carpet, whereas the opposite effect was observed on hard floorings. Higher surface dust loading was associated with lower resuspension fractions on carpets, while on hard floorings the effect of surface dust loading varied with different RH levels.
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