Power-delay-product optimal repeater design for horizontal and vertical multilayer graphene nanoribbon interconnects

Journal of Computational Electronics - Power-delay-product optimal design of repeater size and number design for both horizontal and vertical multilayer graphene nanoribbon (MLGNR) interconnects is...     

A Taguchi design approach for the enhancement of a detergent-biocompatible alkaline thermostable protease production by Streptomyces mutabilis strain TN-X30

The ability of microorganisms to grow at high temperature, alkaline pH, and high salinity makes them an attractive target for enzyme-production with several industrial applications. One strain TN-X30 has been selected as protease producer and identified as Streptomyces mutabilis after a phenotypic and molecular study. Its production of protease was improved using Taguchi L27 design. The strategy was carried out to identify the optimum levels and the interaction of the screened factors. Following this step, maximum protease activity (10,895 U/ml) was achieved after 6-days of incubation. The TN-X30 protease activity had an optimum of pH and temperature of 10 and 65°C, respectively. Thermodynamic parameters at 60°C were enthalpy 14.26 kJ/mol, entropy −220 J/mol/K, and Gibbs free energy 90.53 kJ/mol. TN-X30 protease production displayed a 16-fold increase reaching 175,000 U/ml in a 100-L fermentor. Furthermore, the lyophilization in presence of sorbitol enhanced the stability of the TN-X30 protease which remained active at 75% after 24-months of storage. The lyophilized TN-X30 protease exhibited exceptional stability indexes in presence of some known commercialized detergent components as NEODOL® 25-7, Dehydol® LT 7, Na₂ CMC, Galaxy LAS, Galaxy LES 70, Galaxy 110, Galaxy CAPB Plus, and Sulfacid K. The lyophilized enzyme also displayed high stability with respect to both solid and liquid detergents. Finally, TN-X30 protease exhibited remarkable destaining of blood, egg, and chocolate stained cloth pieces. These findings may promote TN-X30 protease for use as bioadditive in detergent formulation, thereby reducing environmental chemical threat.     

Processing and 3D printing of SiCN polymer-derived ceramics

Preceramic polymer resins are attractive for the 3D printing of net-shaped ceramic components. Recently various processes have been demonstrated for 3D printing of polymer-derived ceramics (PDCs). Ultimately in these processes, the process outcomes strongly depend on the process parameters. In particular, for PDCs the ceramic density, and ceramic yield are affected by the catalyst concentration and cross-linking duration. Here, we use thermal analysis and FTIR to quantify the interrelation of the process parameters on the process outcome for polysilazanes and demonstrate 3D printing of PDC components based on the best-identified process parameters. The results of this work can be used as guidelines for future additive manufacturing of PDCs.     

The Capability Assessment of the Spectrum Decomposition Technique for Measurements of the Group Velocity of Lamb Waves

The ultrasonic guided waves are dispersive waves characterized by the phase and group velocities dispersion curves. In order to use guided waves in various industrial applications, their parameters must be known. Since these guided wave velocities depend on the frequency and thickness of the material, they propagate differently comparing to bulk ultrasonic waves. Therefore, to analyze the parameters of such waves, new measurement techniques should be proposed and possibilities of their application have to be investigated. In this paper possibilities to measure the group velocity based on the spectrum decomposition approach are presented. The investigations are carried out using the simulated and experimental signals of Lamb wave propagating in a 2 mm thickness aluminium plate. The two fundamental modes \(\hbox {A}_{0}\) and \(\hbox {S}_{0}\) are selected. Using the proposed technique, segments of the group velocity dispersion curves have been reconstructed and compared with the dispersion curves calculated by the SAFE method to estimate errors. Accordingly to the obtained lower absolute and relative errors, an optimal set of narrowband filters with bandwidth from 20 kHz up to 100 kHz for the \(\hbox {A}_{0}\) mode and from 80 kHz up to 160 kHz for the \(\hbox {S}_{0}\) mode are proposed. Applying the proposed optimal frequency sets of narrowband filters for the experimental signals, segments of the group velocity dispersion curves for both modes are reconstructed. The average relative error for the \(\hbox {A}_{0}\) mode is 1.7–2.2% (expanded relative uncertainty ± (2.2–2.8)%) and 0.78–1.2% (expanded relative uncertainty ± (0.5–0.8)%) for the \(\hbox {S}_{0}\) mode.     

Application of Deep Hole Drilling to the Measurement and Analysis of Residual Stresses in Steel Shrink‐Fitted Assemblies

Abstract: Residual stress measurement of shrink‐fitted assemblies was achieved through finite element simulations and experiments using the deep hole drilling technique. Shrink‐fitted assemblies using stainless steel and cast iron were manufactured and residual stresses measured using a combination of deep hole and centre hole drilling. The results from the finite element simulations demonstrated that modifications to the deep hole drilling method were required to account for plastic relaxation during the measurement process. This was verified through the experimental measurements. The results from both the stainless steel and cast iron assemblies provided a clear demonstration that the final residual stress state was a consequence of the machining and assembly of the components.     

Multi-level cross-layer protocol for end-to-end delay provisioning in wireless multimedia sensor networks

Frontiers of Information Technology & Electronic Engineering - Rapid developments in information and communication technology in recent years have posed a significant challenge in wireless...     

Numerical simulation of steady natural convection heat transfer in a 3-dimensional single-ended tube subjected to a nanofluid

In this paper, 3-dimensional numerical simulation of steady natural convective flow and heat transfer are studied in a single-ended tube with non-uniform heat input. Apart from some other applications, it serves as a simplified model of the single-ended evacuated solar tube of a water-in-glass evacuated tube solar water heater. It is assumed that the sealed end of tube to be adiabatic and also the tube opening to be subjected to copper–water nanofluid. Governing equations are derived based on the conceptual model in the cylindrical coordinate system. The governing equations have been then approximated by means of a fully implicit finite volume control method (FVM), using SIMPLE algorithm on the collocated arrangement. The study has been carried out for solid volume fraction 0 ≤ φ ≤ 0.05 and maximum heat flux 100 ≤ q_m ≤ 700. Considering that the driven flow in the tube is influenced by the dimensions and the inclination angle of the solar tube, the flow patterns and temperature distributions are presented on different cross sectional planes and longitudinal sections, when the tube is positioned at different orientations.     

Generation of motional entangled coherent state in an optomechanical system in the single photon strong coupling regime

The single-photon strong coupling in the deep-resolved sideband of the optomechanical system induces photon blockade (PB) effect. For the PB cavity, an initial mechanical coherent state evolves into superposition of phonon cat states entangled with the cavity Fock states. Measurement of the cavity photon number states produces phonon even and odd cat states. The information leakage effect of two photon states on the fidelity of cat states is calculated, it is shown that for low average phonon number this effect is negligible and decreases by increasing the two photon cavity state. The Lindblad equation is solved numerically to obtain the environmental effects on the fidelity of cat states.     

Velocity field and pressure distribution around a collapsing cavitation bubble during necking and splitting

The hydrodynamic behavior of the fluid around a cavitation bubble located above a rigid boundary is investigated numerically. The liquid around the cavitation bubble is assumed to be incompressible, inviscid and irrotatational and surface tension is assumed to be negligible. Boundary-integral-equation and finite-difference methods are employed to study the problem. Three cases are investigated: (1) when the Bjerknes force is negligible in comparison with the buoyancy force, (2) when the buoyancy force is negligible in comparison with the Bjerknes force, (3) when the Bjerknes attraction force through the rigid surface and the buoyancy force are comparable. It is shown that during the collapse phase in the third case, an annular liquid jet develops around the bubble, causing it to take the shape of an hour-glass. This phenomenon is called necking which is followed by splitting the bubble into two parts. Features to note are the large lateral pressures and the high relative velocities of the fluid particles near the annular liquid jet of the bubble. This large lateral pressure may be the cause of bubble collapse. The velocity field of the liquid domain around the two parts of the cavitation bubble after splitting shows that a stagnation point exists between the two parts of the bubble. Because of the unsteady nature of the problem, the stagnation point and the point of maximum pressure do not coincide.     

The influence of fiber fineness on physical characteristics of staple polypropylene fibers spun at different pumping speeds

Melt spinning and pump speed conditions are described for five samples of staple polypropylene PP fibers of different fineness. The influence of fiber fineness or denier on the physical characteristics of staple PP fibers spun at different pump speeds was studied. Optical anisotropy was measured using two‐beam interference microscopy. Enthalpy and degree of crystallinity were measured using differential scanning calorimetry technique for studied fibers. The relation between the fiber diameter, crimp ratio, tenacity, and degree of orientation with the fiber denier are given. A selection of microinterferograms of fibers is given for illustration. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010