Solid Freeform Fabrication of Functional Silicon Nitride Ceramics by Laminated Object Manufacturing 1

The processing of silicon nitride (Si3N4) structural ceramics by Laminated Object Manufacturing (LOM) using ceramic tape preforms was investigated. The key processing stages involved green shape formation (which used the LOM process), followed by the burnout of all organics, and final densification by pressureless sintering. Two material systems were considered. These were a) monolithic Si3N4 and b) a preceramic polymer infiltrated Si3N4. The raw materials for the process were tape preforms of Si3N4, which were fabricated by standard tape casting techniques. Mechanical property data obtained for the LOM processed Si3N4 showed high strength and fracture toughness values. The room temperature and high temperature (1260 o C) flexural strengths were in the range of 700-900 MPa and 360-400 MPa, respectively. The fracture toughness averaged from 5.5-7.5 MPa.m1/2. These strength and fracture toughness values are comparable to those reported for conventionally prepared Si3N4 ceramics. Thus, this research demonstrated that the LOM technique is a viable method for preparing functional Si3N4 ceramics with good physical and mechanical properties.Mechanical Engineerin

Deep equilibrium networks are sensitive to initialization statistics

Deep equilibrium networks (DEQs) are a promising way to construct models which trade off memory for compute. However, theoretical understanding of these models is still lacking compared to traditional networks, in part because of the repeated application of a single set of weights. We show that DEQs are sensitive to the higher order statistics of the matrix families from which they are initialized. In particular, initializing with orthogonal or symmetric matrices allows for greater stability in training. This gives us a practical prescription for initializations which allow for training with a broader range of initial weight scales

Towards Benchmarking Scene Background Initialization

Given a set of images of a scene taken at different times, the availability of an initial background model that describes the scene without foreground objects is the prerequisite for a wide range of applications, ranging from video surveillance to computational photography. Even though several methods have been proposed for scene background initialization, the lack of a common groundtruthed dataset and of a common set of metrics makes it difficult to compare their performance. To move first steps towards an easy and fair comparison of these methods, we assembled a dataset of sequences frequently adopted for background initialization, selected or created ground truths for quantitative evaluation through a selected suite of metrics, and compared results obtained by some existing methods, making all the material publicly available.Comment: 6 pages, SBI dataset, SBMI2015 Worksho

Phases and quantum phase transitions in the anisotropic antiferromagnetic Kitaev-Heisenberg-T magnet

We study the Kitaev-Heisenberg-P model with antiferromagnetic Kitaev exchanges in the strong anisotropic (toric code) limit to understand the phases and the intervening phase transitions between the gapped Z2 quantum spin liquid and the spin-ordered (in the Heisenberg limit) as well as paramagnetic phases (in the pseudodipolar, Gamma, limit). We find that the paramagnetic phase obtained in the large Gamma limit has no topological entanglement entropy and is proximate to a gapless critical point of a system described by equal superposition of differently oriented stacked one-dimensional Z2 x Z2 symmetry protected topological phases. Using a combination of exact diagonalization calculations and field theoretic analysis we map out the phases and phase transitions to reveal the complete phase diagram as a function of the Heisenberg, the Kitaev, and the pseudodipolar interactions. Our work shows a rich plethora of unconventional phases and phase transitions and provides a comprehensive understanding of the physics of anisotropic Kitaev-Heisenberg-P systems along with our recent pape

Pm(III), Eu(III), Tb(III), Pd(II), Pt(II) & Ir(II) Complexes of Picramic Acid

470-47

Hairy Leukoplakia

Oral hairy leukoplakia (OHL) is a disease of the mucosa first described in 1984. This pathology is associated with Epstein-Barr virus (EBV) and occurs mostly in people with HIV infection, both immunocompromised and immunocompetent, and can affect patients who are HIV negative. [1, 2] The first case in an HIV-negative patient was reported in 1999 in a 56-year-old patient with acute lymphocytic leukemia. Later, many cases were reported in heart, kidney, and bone marrow transplant recipients and patients with hematological malignancies. [3, 4

Chiral metals and entrapped insulators in a one-dimensional topological non-Hermitian system

In this work, we study many-body "steady states" that arise in the non-Hermitian generalization of the noninteracting Su-Schrieffer-Heeger model at a finite density of fermions. We find that the hitherto known phase diagrams for this system, derived from the single-particle gap closings, in fact correspond to distinct nonequilibrium phases, which either carry finite currents or are dynamical insulators where particles are entrapped. Each of these have distinct quasiparticle excitations and steady-state correlations and entanglement properties. Looking at finite-sized systems, we further modulate the boundary to uncover the topological features in such steady states, particularly the emergence of leaky boundary modes. Using a variety of analytical and numerical methods, we develop a theoretical understanding of the various phases and their transitions, and we uncover the rich interplay of nonequilibrium many-body physics, quantum entanglement, and topology in a simple looking yet rich model system

Complexing Behaviour of 2-Thioorotic Acid: Complexes of Co(II), Fe(II), Rh(III), Pd(IV) & Pt(IV)

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