Study of QCD generalized ghost dark energy in FRW universe

A phenomenological generalized ghost dark energy model has been studied under the framework of FRW universe. In ghost dark energy model the energy density depends linearly on Hubble parameter (H) but in this dark energy model, the energy density contains a the sub-leading term which is depends on $\mathcal{O} (H^2)$, so the energy density takes the form $\rho_D=\alpha H+ \beta H^2$, where $\alpha$ and $\beta$ are the constants. The solutions of the Friedman equation of our model leads to a stable universe. We have fitted our model with the present observational data including Stern data set. With the help of best fit results we find the adiabatic sound speed remains positive throughout the cosmic evolution, that claims the stability of the model. The flipping of the signature of deceleration parameter at the value of scale factor $a=0.5$ indicates that the universe is at the stage of acceleration i.e. de Sitter phase of the universe at late time. Our model shows that the acceleration of the universe begin at redshift $z_{ace}\approx 0.617$ and the model is also consistent with the current observational data.Comment: 9 pages, 9 figure

Profitability of Integrated Farming System model for small and medium farmers of South Tripura, Tripura

The present study was carried out under Krishi Vigyan Kendra, South Tripura to study the production, profitability and employment generation of IFS over prevailing conventional rice-rice system of farming in South Tripura district of Tripura during 2015-16, 2016-17 and 2017-18. The components rice, maize, vegetables, ginger, apiculture, fishery, poultry and piggery were considered for the study under integrated farming system. The Integrated Farming System (IFS) model showed 17.79 % increase in productivity and 48.91 % higher net return over conventional rice-rice system.  Among the components evaluated, the highest per cent net return was received from Fishery unit (31.78), followed by Piggery unit (18.19), Apiculture (13.93), Poultry unit (12.96), Spice Ginger (10.19), Crop (7.31) and Vegetables (5.64) respectively. The highest B:C ratio (3.67) was obtained from fishery unit among all the component evaluated under the IFS. A total of 289 Man days/ha/year employments can be generated under Integrated Farming System. This system of IFS model may be useful in the areas where water is limiting and an efficient alternate system of conventional rice-rice system

Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation IV: Background Simulations using GEANT-4 Toolkit

Hard X-ray detectors in space are prone to background signals due to the ubiquitous cosmic rays and cosmic diffuse background radiation that continuously bombards the satellites which carry the detectors. In general, the background intensity depends on the space environment as well as the material surrounding the detectors. Understanding the behavior of the background noise in the detector is very important to extract the precise source information from the detector data. In this paper, we carry out Monte Carlo simulations using the GEANT-4 toolkit to estimate the prompt background noise measured with the detectors of the RT-2 Experiment onboard the CORONAS-PHOTON satellite.Comment: 21 pages, 10 figures, Accepted for publication in Experimental Astronomy (in press

Electric Switching of the Charge-Density-Wave and Normal Metallic Phases in Tantalum Disulfide Thin-Film Devices

We report on switching among three charge-density-wave phases - commensurate, nearly commensurate, incommensurate - and the high-temperature normal metallic phase in thin-film 1T-TaS2 devices induced by application of an in-plane electric field. The electric switching among all phases has been achieved over a wide temperature range, from 77 K to 400 K. The low-frequency electronic noise spectroscopy has been used as an effective tool for monitoring the transitions, particularly the switching from the incommensurate charge-density-wave phase to the normal metal phase. The noise spectral density exhibits sharp increases at the phase transition points, which correspond to the step-like changes in resistivity. Assignment of the phases is consistent with low-field resistivity measurements over the temperature range from 77 K to 600 K. Analysis of the experimental data and calculations of heat dissipation suggest that Joule heating plays a dominant role in the electric-field induced transitions in the tested 1T-TaS2 devices on Si/SiO2 substrates. The possibility of electrical switching among four different phases of 1T-TaS2 is a promising step toward nanoscale device applications. The results also demonstrate the potential of noise spectroscopy for investigating and identifying phase transitions in materials.Comment: 32 pages, 7 figure

Spin - Phonon Coupling in Nickel Oxide Determined from Ultraviolet Raman Spectroscopy

Nickel oxide (NiO) has been studied extensively for various applications ranging from electrochemistry to solar cells [1,2]. In recent years, NiO attracted much attention as an antiferromagnetic (AF) insulator material for spintronic devices [3-10]. Understanding the spin - phonon coupling in NiO is a key to its functionalization, and enabling AF spintronics' promise of ultra-high-speed and low-power dissipation [11,12]. However, despite its status as an exemplary AF insulator and a benchmark material for the study of correlated electron systems, little is known about the spin - phonon interaction, and the associated energy dissipation channel, in NiO. In addition, there is a long-standing controversy over the large discrepancies between the experimental and theoretical values for the electron, phonon, and magnon energies in NiO [13-23]. This gap in knowledge is explained by NiO optical selection rules, high Neel temperature and dominance of the magnon band in the visible Raman spectrum, which precludes a conventional approach for investigating such interaction. Here we show that by using ultraviolet (UV) Raman spectroscopy one can extract the spin - phonon coupling coefficients in NiO. We established that unlike in other materials, the spins of Ni atoms interact more strongly with the longitudinal optical (LO) phonons than with the transverse optical (TO) phonons, and produce opposite effects on the phonon energies. The peculiarities of the spin - phonon coupling are consistent with the trends given by density functional theory calculations. The obtained results shed light on the nature of the spin - phonon coupling in AF insulators and may help in developing innovative spintronic devices.Comment: 16 pages; 2 figure

Cranial nerve palsy in cerebral venous sinus thrombosis and response to therapy

Clinical presentation of cerebral venous sinus thrombosis (CVST) is variable. The most common symptom of CVST is headache. Cranial nerve palsy in CVST is rare. We present a case of CVST due to oral contraceptive pill usage presented with cranial nerve palsy. A 28 year old female presented with complains of headache and blurring of vision. On further evaluation, we found left 6th cranial nerve palsy with diminished vision on both eyes (left more than right). Initial CT brain imaging was normal. Magnetic resonance venography revealed thrombosis of superior sagittal sinus, right transverse sinus, and right sigmoid sinus extending into the right internal jugular vein. At the end of 6 months of anticoagulation therapy there is marked improvement of vision and complete recovery of left 6th nerve palsy. Though cranial nerve palsy in CVST have been reported previously, new findings of this case is that more sign contralateral to site of lesion and variable response to therapy

The Study of Optical Properties for Ordered and Disordered Silicon Nanowire Structures

We designed ordered and disordered silicon (Si) nanowire structures and analyzed their optical performance using the finite-difference time-domain (FDTD) technique. We studied the orderness of nanowire structures by calculating scalar variance. This study reveals that utilizing disorder structures can increase the average absorbance of Si nanowire structures. Spatial electric field distributions provided insights into light-matter interaction, indicating that disorder structures had higher path lengths compared to the periodic structure. We achieved an average absorbance of 41.46% for the hyperuniform Si nanowire structure with a maximum absorbance of 78.18%. Intuitively, we obtained ~70% high absorbance compared to periodic Si nanowire structure. Our findings will be conducive to designing new efficient solar cells and photodetectors.Comment: This paper includes 4 pages, 5 figures, and 1 tabl

Density Evolution in the New Modified Chaplygin Gas Model

In this paper, we have considered new modified Chaplygin gas (NMCG) model which interpolates between radiation at early stage and $\Lambda$CDM at late stage. This model is regarded as a unification of dark energy and dark matter (with general form of matter). We have derived the density parameters from the equation of motion for the interaction between dark energy and dark matter. Also we have studied the evolution of the various components of density parameters.Comment: 6 Latex pages, 4 figures, RevTex styl