New technology may help scale up memory storage capacity

Silicon-based memory devices such as hard drives and flash drives are in high demand for gadgets that require storage. Conventional semiconductor material-based memory devices have limited scale-up ability to increase their storage capacity. Hence, there is a quest in developing new memory technologies with superior characteristics. In this direction, a group of Indian researchers has developed a new type of resistive random access memory (RRAM) device that can be controlled with magnetic fields

Enhanced spin – reorientation temperature and origin of magnetocapacitance in HoFeO3

We report on the increase in the spin reorientation temperature in HoFe0.5Cr0.5O3 compound by isovalent substitution (Cr3+) at the Fe-site and the magnetocapacitance in the HoFeO3 compound. Spin reorientation transition is evident around 50 K and 150 K for the x=0 and x=0.5 compounds respectively. The increase in the spin reorientation transition temperature in case of x=0.5 compound can be attributed to the domination of the Ho3+- Fe3+ interaction over the Fe3+- Fe3+ interaction. Decrease in Néel temperature from 643 K (x=0) to 273 K (x=0.5) can be ascribed to the decrease in the interaction between antiferromagnetically aligned Fe3+ moments as a result of the dilution of the Fe3+ moments with the Cr3+ addition. From the magnetization M vs. magnetic field H variation it is evident that the coercivity, HC decreases for x=0.5 compound, hinting the magnetic softening of the HoFeO3 compound. Observed magnetocapacitance could be due to lossy dielectric mechanism in the present compound. Indeed, present results would be helpful in understanding the physics behind rare- earth orthoferrites

Magnetic and magnetocaloric properties of HoCr0.75Fe0.25O3 compound

We report on the magnetic and magnetocaloric properties of HoCr0.75Fe0.25O3 compound around the Néel temperature (TN), which is due to Cr3+ ordering. Susceptability (χ) vs. temperature (T) graph of HoCr0.75Fe0.25O3 compound infer two transitions due to the ordering of Cr3+ moments (TN ~ 155 K) and Ho3+ moments (TNHo ~ 8 K). Magnetic entropy (–ΔSM) value of 1.14 J kg-1 K-1 around 157.5 K with a magnetic field (H) of 90 kOe is attributed to antiferromagnetic (AFM) ordering of Cr3+ moments. A maximum value of adiabatic temperature (ΔTad) ~ 0.41 K around TN is obtained and is found to increases with applied magnetic field. Negative slope for H/M vs. M2 graph is evident for HoCr0.75Fe0.25O3 compound below TN, which indicates the first order phase transition. Quantified values of – ΔSM and ΔTad opens up the way to explore rare earth orthochromites for the MCE properties and refrigeration applications

Magnetocaloric effect and nature of magnetic transition in low dimensional DyCu2

In this manuscript, we propose a method to prepare small flakes of DyCu2. On top of that we also report on the magnetocaloric effect and nature of magnetic transition of a strongly anisotropic DyCu2 in its low dimension. Magnetization measurements were carried out in the temperature range of 5-100 K and up to the maximum magnetic field strength of 50 kOe. Magnetic entropy change (Delta S-M) is estimated using the well-known Maxwell's equations and is found to be -4.31 J/kg-K. Indeed, the Delta S-M peak broadened marginally compared with its bulk DyCu2 and such a broadening can be attributed to significant increase in the total grain boundary volume. As these small flakes consists larger DSM values at temperatures higher than the Neel temperature (T-N), one can use them as a magnetic refrigerant material in a broad temperature range. We also plotted the M-2 vs. H/M (which are called as the Arrott plots) in order to find the nature of magnetic transition. Arrott plots infer that indeed there exists nonlinearity in M-2 vs. H/M behavior and such nonlinear behavior is ascribed to the random anisotropy or a random field that is present in the system

Learning fast, accurate, and stable closures of a kinetic theory of an active fluid

Important classes of active matter systems can be modeled using kinetic theories. However, kinetic theories can be high dimensional and challenging to simulate. Reduced-order representations based on tracking only low-order moments of the kinetic model serve as an efficient alternative, but typically require closure assumptions to model unrepresented higher-order moments. In this study, we present a learning framework based on neural networks that exploit rotational symmetries in the closure terms to learn accurate closure models directly from kinetic simulations. The data-driven closures demonstrate excellent a-priori predictions comparable to the state-of-the-art Bingham closure. We provide a systematic comparison between different neural network architectures and demonstrate that nonlocal effects can be safely ignored to model the closure terms. We develop an active learning strategy that enables accurate prediction of the closure terms across the entire parameter space using a single neural network without the need for retraining. We also propose a data-efficient training procedure based on time-stepping constraints and a differentiable pseudo-spectral solver, which enables the learning of stable closures suitable for a-posteriori inference. The coarse-grained simulations equipped with data-driven closure models faithfully reproduce the mean velocity statistics, scalar order parameters, and velocity power spectra observed in simulations of the kinetic theory. Our differentiable framework also facilitates the estimation of parameters in coarse-grained descriptions conditioned on data

Supersymmetric Electromagnetic Waves on Giants and Dual-Giants

We set up the BPS equations for a D3-brane moving in AdS_5 \times S^5 which preserves two supercharges and with all bosonic fields turned on in the world-volume theory. By solving these, we find generalizations of Mikhailov giants and wobbling dual-giants that include electromagnetic waves propagating on their world-volume. For these giants (dual-giants) we show that the BPS field strength is the real part of the pull-back of a holomorphic 2-form in the ambient space C^3 (C^{1,2}) onto the world-volume.Comment: 18 page

Prospective, randomized, and comparative study of efficacy of ivermectin, benzyl benzoate 25%, permethrin 5% and gamma benzene hexachloride 1% in the treatment of uncomplicated scabies

Background: Scabies is an infectious and contagious human skin disease. The aim of the study was to study the efficacy and safety of four different treatment modalities in clinically diagnosed cases of scabies of single dose of oral ivermectin and commonly used topical scabicidal agent’s benzyl benzoate 25% (BB), permethrin 5% and gamma benzene hexachloride 1% (GBHC).Methods: This study was carried out in the Department of Dermatology, Andhra Medical College, Visakhapatnam. 200 patients diagnosed of scabies were included in the study during the period from August 2013 to July 2014. The percentage of improvement was compared between four groups. Intergroup comparison between two groups was done Chi square test.Results: In the present study a greater number of patients were students (54.5%). Subsidence of lesion and itching with oral ivermectin given as a single dose (200 μg/kg body weight) was 45 (90%) and 44 (88%), with topical permethrin 5% lotion single application 48 (96%), 47 (94%), with topical GBHC 1% lotion 40 (80%) patients, 38 (76%). Topical application of BB lotion 25% was 38 (76%), and 36 (72%) at fourth week.Conclusions: In the present study permethrin 5% cream was found to be more effective among topical agents. Both BB and GBHC 1% lotion are being inexpensive and they can be used as an alternative treatment in developing country like India

Ab-initio investigation of finite size effects in rutile titania nanoparticles with semilocal and nonlocal density functionals

In this work, we employ hybrid and generalized gradient approximation (GGA) level density functional theory (DFT) calculations to investigate the convergence of surface properties and band structure of rutile titania (TiO$_2$) nanoparticles with particle size. The surface energies and band structures are calculated for cuboidal particles with minimum dimension ranging from 3.7 \r{A} (24 atoms) to 10.3 \r{A} (384 atoms) using a highly-parallel real-space DFT code to enable hybrid level DFT calculations of larger nanoparticles than are typically practical. We deconvolute the geometric and electronic finite size effects in surface energy, and evaluate the influence of defects on band structure and density of states (DOS). The electronic finite size effects in surface energy vanish when the minimum length scale of the nanoparticles becomes greater than 10 \r{A}. We show that this length scale is consistent with a computationally efficient numerical analysis of the characteristic length scale of electronic interactions. The surface energy of nanoparticles having minimum dimension beyond this characteristic length can be approximated using slab calculations that account for the geometric defects. In contrast, the finite size effects on the band structure is highly dependent on the shape and size of these particles. The DOS for cuboidal particles and more realistic particles constructed using the Wulff algorithm reveal that defect states within the bandgap play a key role in determining the band structure of nanoparticles and the bandgap does not converge to the bulk limit for the particle sizes investigated

Counting 1/8-BPS Dual-Giants

We count 1/8-BPS states in type IIB string theory on AdS_5 x S^5 background which carry three independent angular momenta on S^5. These states can be counted by considering configurations of multiple dual-giant gravitons up to N in number which share at least four supersymmetries. We map this counting problem to that of counting the energy eigen states of a system of N bosons in a 3-dimensional harmonic oscillator. We also count 1/8-BPS states with two independent non-zero spins in AdS_5 and one non-zero angular momentum on S^5 by considering configurations of arbitrary number of giant gravitons that share at least four supersymmetries.Comment: 19 page