Thermal modes of bimolecular exothermic reactions: Concentration limits of ignition

In the present work, the analytical investigation of the phase trajectories structures on the plane: heating rate-temperature for bimolecular exothermic reactions was carried out. This gave a possibility to divide the parametric plane Todes parameter–Semenov parameter into five characteristic regions with various modes of self-heating. It was established that all regions converge at a single point which determines the thermal explosion degeneration conditions. The correlation between Todes parameter, Semenov parameter and concentration ratio of initial reactants at the limit of the thermal explosion degeneration was found. The critical conditions for thermal explosion at any ratio of concentrations of initial reactants were determined. The approach proposed is a general one and allows analyzing both first and second order reactions.     

Characterization of interdependency between intracranial pressure and heart variability signals: a causal spectral measure and a generalized synchronization measure

Causal coherence and generalized synchronization (GS) index were extracted from beat-to-beat mean intracranial pressure (ICP) and intervals between consecutive normal sinus heart beats (RR interval) that were recorded from 12 patients undergoing normal pressure hydrocephalus diagnosis. Data were organized into two groups including an ICP B-Wave group and a baseline control group. Maximal classic coherence (CC) between ICP and RR interval within [0.04, 0.15] Hz was found to be significantly greater than zero for both B-Wave and control groups with B-Wave CC greater than that of the baseline group. Causal coherence analysis further revealed that feedforward coherence due to RR interval's effect on ICP always exists for both B-Wave and baseline ICP state and no significant difference exists between two groups. On the other hand, feedback coherence from ICP to RR interval was enhanced during the occurrence of B-Wave. This finding regarding the enhanced directional, from ICP to RR interval, coupling between ICP and RR interval was also confirmed by a modified GS measure.     

Flexible Silk–Inorganic Nanocomposites: From Transparent to Highly Reflective

A novel type of all‐natural, biocompatible, and very robust nanoscale free‐standing biohybrids are reported. They are obtained by integrating a silk fibroin matrix with functional inorganic nanoplatelets using a spin‐assisted layer‐by‐layer assembly. The organized assembly of the silk fibroin with clay (montmorillonite) nanosheets results in highly transparent nanoscale films with significantly enhanced mechanical properties, including strength, toughness, and elastic modulus, as compared to those for the pristine silk nanomaterials. Moreover, replacing clay nanoplatelets with a highly reflective Langmuir monolayer of densely packed silver nanoplates causes a similar enhancement of the mechanical properties, but in contrast to the materials above, highly reflective, mirror‐like, nanoscale flexible films are created. This strategy offers a new perspective for the fabrication of robust all‐natural flexible nanocomposites with exceptional mechanical properties important for biomedical applications, such as reinforced tissue engineering. On the other hand, the ability to convert silk‐based nanoscale films into mirror‐like biocompatible flexible films can be intriguing for prospective photonics and optical exploitation of these nanobiohybrids.     

Liquid/liquid phase equilibrium in globulin/salt/water systems: Legumin

The effects of temperature, concentration and nature of neutral salts, pH, glycine and ethanol concentration on the liquid/liquid phase equilibrium in broad bean legumin/salt/water and pea legumin/salt/water systems was investigated. The coexistence curves have upper critical points. The shape of the coexistence curve was independent of the above factors. Gas theory and Kirkwood-Fuoss theory for dipole-dipole and ion-dipole interactions were used to describe the systems. It is suggested that the value of the excluded volume of protein molecules, the energy balance of dipole-dipole interaction between protein molecules, ion-dipole interaction of protein molecules with low molecular weight ions, and the energy of thermal motion of protein molecules are the main factors of the investigated phenomenon.     

Multi-scale Simulation Methodology for Stress Assessment in 3D IC: Effect of Die Stacking on Device Performance

Potential challenges with managing mechanical stress distributions and the consequent effects on device performance for advanced 3D integrated circuit (IC) technologies are outlined. A set of physics-based compact models for a multi-scale simulation, to assess the mechanical stress across the device layers in silicon chips stacked and packaged with the 3D through-silicon-via (TSV) technology, is proposed. A calibration technique based on fitting to measured stress components and electrical characteristics of the test-chip devices is presented. For model validation, high-resolution strain measurements in Si channels of the test-chip devices are needed. At the nanoscale, the transmission electron microscopy (TEM) is the only technique available for sub-10 nm strain measurements so far.     

Multiple nano-blast synthesis of PT/8Y-ZP composite nanopowders

We demonstrate a processing technique based on the synthesis of ceramic nanopowders and simultaneous impregnation with metallic nanoparticles by multiple 'nano-blasts' of embeded cyclotrimethylene trinitramine in preliminary engineered multi-component nano-reactors. 'Nano-blasts' of impregnated cyclotrimethylene trinitramine deagglomerate the nanopowder due to the high energetic impacts of the blast waves, while the decomposition of compounds and their solid-solubility is enhanced by the extremely high local temperature generated during the nano-explosions. We applied this technique to produce nanosized agglomerate-free 8 mol% yttria-doped cubic zirconia aggregates with an average size of 53 nm impregnated with 10 mass% of platinum particles of 2-14 nm.     

Characteristics of PAHs,PCDD/Fs,PCBs and PBDEs in the Sediment of Lake Baikal,Russia

The levels of PAHs, PCDD/Fs, PCBs, and PBDEs in Lake Baikal were monitored for the first time using deep water sediment. The sediment samples were collected from 15 stations in four regions of Lake Baikal: Ol’khon Island (n = 8), the Angara River estuary (n = 2), the Selenga River delta (n = 2), and the Baikal pulp and paper mill (BPPM) (n = 3). The highest average concentrations of PCDD/Fs (20.24 pg/g d.w.) and PCBs (68.72 ng/g d.w.) were found at Ol’khon Island. The highest total PBDE concentrations were found at BPPM, with a mean concentration of 575.76 pg/g d.w. For PCBs, PCB-52, and PCB-69 were dominant, making up 11% of the total 209 PCB congeners. BDE-209 contributed 60% of PBDEs in Lake Baikal. According to the TPEQ concentration of PAHs, PAHs contributed the most to Lake Baikal contamination. The sources of contamination of PAHs, PCDDs, and PCBs in Lake Baikal are identified as combustion, runoff from the use of the pesticides (PCP) and insulating oil, specifically for PCBs. The source of PBDEs is assumed to be production, use and disposal of products containing PBDEs, in addition to atmospheric long-range transport and deposition.     

Controlling the dynamic behavior of piezoceramic cylinders by cross-section geometry

This paper focuses on the possibilities of controlling the dispersion spectra and wave characteristics of cylindrical waveguides by changing their geometry and electro-elastic properties. We consider cylinders with classical circular and hollow cross-sections, and waveguides that have sector cut of arbitrary angular measure in the cross-section. Numerical results are presented for the cylinders of all studied types with different boundary conditions. It is shown that the required wave characteristics can be obtained by a variation of the cross-section geometry of the waveguides.     

Models of thermomechanical behavior of polymeric materials undergoing glass transition

The phenomenological models of the thermomechanical behavior of polymeric materials in a temperature range including the relaxation transition from the highly elastic to the glassy state (vitrification) and the reverse transition (softening) are considered. A model based on the interpretation of the glass transition as a process of gradual increase in intermolecular bonds in the polymer network, “freezing” the current strain with decreasing temperature is developed. A scalar parameter is introduced—the “degree of vitrification,” to establish the quantitative dependence of the relaxation transition completion by temperature. Constitutive relations of thermomechanical behavior of vitrifying polymers in uniaxial and complicated stress states in the “elastic approximation” simplification are obtained. A system of experiments for the identification of the proposed model material functions and constants is formulated and implemented. Analytical model problems are solved, clearly illustrating the mechanism for generation of technological and residual stresses in glass polymers in non-uniform cooling.