Violation of Porod law in a freely cooling granular gas in one dimension

We study a model of freely cooling inelastic granular gas in one dimension, with a restitution coefficient which approaches the elastic limit below a relative velocity scale v. While at early times (t << 1/v) the gas behaves as a completely inelastic sticky gas conforming to predictions of earlier studies, at late times (t >> 1/v) it exhibits a new fluctuation dominated phase ordering state. We find distinct scaling behavior for the (i) density distribution function, (ii) occupied and empty gap distribution functions, (iii) the density structure function and (iv) the velocity structure function, as compared to the completely inelastic sticky gas. The spatial structure functions (iii) and (iv) violate the Porod law. Within a mean-field approximation, the exponents describing the structure functions are related to those describing the spatial gap distribution functions.Comment: 4 pages, 5 figure

Renormalization Group Approach for Modified vdP Oscillator with PT\mathcal{PT} Symmetric Non-Hermitian Interaction

We consider a modified version of the well-known 2d vdP oscillator with a new non-Hermitian interaction. The usual perturbative approach fails to provide the classical dynamics of the system as the classical solutions become divergent in the long time limit. These kinds of divergences are similar to what occurs in quantum field theory and critical phenomena. The Renormalization Group (RG) technique for the dynamical system has been used to eliminate the divergences in the perturbative solution of the 2d vdP oscillator and to provide a physically acceptable solution which is shown to be consistent with numerical study. We further investigate the model in the framework of non-Hermitian quantum mechanics to show the $\mathcal{PT}$ phase transition in the system.Comment: 12 pages, Latex, 6 Fig

Coarse grained dynamics of the freely cooling granular gas in one dimension

We study the dynamics and structure of clusters in the inhomogeneous clustered regime of a freely cooling granular gas of point particles in one dimension. The coefficient of restitution is modeled as $r_0<1$ or 1 depending on whether the relative speed is greater or smaller than a velocity scale $\delta$. The effective fragmentation rate of a cluster is shown to rise sharply beyond a $\delta$ dependent time scale. This crossover is coincident with the velocity fluctuations within a cluster becoming order $\delta$. Beyond this crossover time, the cluster size distribution develops a nontrivial power law distribution, whose scaling properties are related to those of the velocity fluctuations. We argue that these underlying features are responsible behind the recently observed nontrivial coarsening behaviour in the one dimensional freely cooling granular gas.Comment: 7 Pages, 9 Figure

Ammonia gas sensing property of nanocrystalline Cu2S thin films

Nanocrystalline semiconducting thin films of copper sulphide (Cu2S) were deposited by novel chemical route using aqueous solution of 0.1 M copper chloride, 0.05 M thiourea, complexing agent 10% aqueous ammonia (NH3) and hydrazine hydrate. The characterization and gas sensitivity of as deposited Cu2S thin film sensor have been investigated. The as deposited Cu2S thin films were observed to be very sensitive for NH3 gas at room temperature. Upon exposure of NH3 gas the Cu2S sensors lead to decrease in resistance which is attributed due to inter-conversion of Cu(I) and Cu(II) charge states. The response to ammonia gas by Cu2S thin film is detected at 200 to 500 ppm concentration in air. The maximum sensitivity (19.78%) for ammonia gas by Cu2S sensor was found at 500 ppm gas concentration. The quick response (~60 s) and fast recovery (~90 s) are the main features of these sensors. The effects of gas concentrations on the gas sensing performance of the Cu2S sensor have been studied and discusse

Task scheduling and resource allocation in cloud computing using a heuristic approach

Abstract Cloud computing is required by modern technology. Task scheduling and resource allocation are important aspects of cloud computing. This paper proposes a heuristic approach that combines the modified analytic hierarchy process (MAHP), bandwidth aware divisible scheduling (BATS) + BAR optimization, longest expected processing time preemption (LEPT), and divide-and-conquer methods to perform task scheduling and resource allocation. In this approach, each task is processed before its actual allocation to cloud resources using a MAHP process. The resources are allocated using the combined BATS + BAR optimization method, which considers the bandwidth and load of the cloud resources as constraints. In addition, the proposed system preempts resource intensive tasks using LEPT preemption. The divide-and-conquer approach improves the proposed system, as is proven experimentally through comparison with the existing BATS and improved differential evolution algorithm (IDEA) frameworks when turnaround time and response time are used as performance metrics

Colloidal stability and dielectric behavior of eco-friendly synthesized zinc oxide nanostructures from Moringa seeds

Abstract This study centers on the environmentally benign synthesis of zinc oxide nanoparticles (ZnO NPs) derived from Zn (CH3COO)2·2H2O and Moringa seeds. The synthesized nanostructures underwent comprehensive characterization utilizing diverse analytical techniques, encompassing X-ray diffraction (XRD), UV–VIS spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. XRD measurements coupled with W–H plot transformation unequivocally confirmed the formation of ZnO nanostructures, characterized by an average size of 24.9 nm. UV–VIS spectroscopy, complemented by Kubelka Munk curve analysis, elucidated the direct conduction and determined a bandgap of 3.265 eV. FESEM analysis revealed minimal particle aggregation, showcasing well-defined grain boundaries spanning sizes from 20.4 to 87.7 nm. XPS analysis substantiated the presence of Zn (2p), Zn (3p), Zn (3d), and O (1s). Raman spectroscopy identified E2H as the predominant mode, followed by E1(TO) and (E2H-E2L). ZnO thin films, fabricated via pulsed laser deposition (PLD) and deposited onto silicon (100) substrates, exhibited exemplary morphology and discernible topography, characterized by a normal grain size distribution. Zeta potential tests yielded a value of approximately ( \mathcalligra{z} z ~ − 43.8 mV), indicative of the commendable stability of the colloidal suspension, likely attributable to low particle aggregation. Dielectric measurements conducted on sintered pellets at 900 °C unveiled elevated capacitance and dielectric constant at low frequencies across the temperature range of 289.935–310 K. These findings affirm the potential utility of environmentally synthesized ZnO for a spectrum of applications, including energy devices and nanofluids

Characterization of nickel sulphide thin films prepared by modified chemical method

Semiconducting nickel sulphide (NiS) thin films were deposited onto glass substrates using a new modified chemical bath method (MCBD). The MCBD is the solutions grow technique in which substrates are immersed in cations and anions alternatively and film growth takes place on the substrates. The preparative conditions such as concentration, pH, temperature, immersion time, immersion cycles, etc are optimized to get nanocrystalline NiS films. The characterization of the films was carried out by using X-ray diffraction, scanning electron microscopy, optical absorption and electrical resistivity. The XRD analysis of the as-grown NiS films showed hexagonal structure. The average grain size is found to be 14 nm. Electrical resistivity measurements showed semiconducting nature with at room temperature resistivity which is found to be of the order of 10 Ωcm for as-deposited NiS films. Scanning electron micrographs (SEM) reveal a very dense surface structure with the presence of irregular shaped grain particles of size ~200 nm. The optical absorption studies show that the absorption coefficient of the NiS thin film is high and a direct band gap of ~2.4 eV has been observed

Multimodal Approach to Identify Learning Strategies of Visual and Verbal Learners

This paper presents a multimodal approach to identify learning and learning assessment strategies of visual and verbal learner. V-Square test identifies visual and verbal learners. It uses questions related to visual/verbal dimension of Felder Silverman Model. Learning strategy test identifies the learning strategy of visual, verbal and balanced learner. Learning assessment test deduces assessment strategies for these learners. Both tests uses questions associated with aural and read/write dimensions of VARK model. This paper summarizes data analysis of 62 participants collected in a web based eLearning environment. Analysis serves an important parameter for development of learning and learning assessment objects

Structural, optical and electrical properties of nanocrystalline cadmium sulphide thin films deposited by novel chemical route

Nanocrystalline semiconducting cadmium sulphide(CdS ) thin films have been deposited on glass substrate by relatively simple, quick and cost effective chemical bath route. The deposition kinetics played important role to get good quality nanocrystalline films with uniform thickness. Hence, the preparative parameters such as concentration, temperature, deposition time, pH of solution have been optimized. The characterization of as deposited thin films was carried out for the structural, compositional, surface morphological, optical and electrical properties using X-ray diffraction (XRD), EDAX, Scanning electron microscopy (SEM), UV-VIS Spectra and dc two point probe method