Relative timing [asynchronous design]

Relative timing (RT) is introduced as a method for asynchronous design. Timing requirements of a circuit are made explicit using relative timing. Timing can be directly added, removed, and optimized using this style. RT synthesis and verification are demonstrated on three example circuits, facilitating transformations from speed-independent circuits to burst-mode and pulse-mode circuits. Relative timing enables improved performance, area, power, and functional testability of up to a factor of 3/spl times/ in all three cases. This method is the foundation of optimized timed circuit designs used in an industrial test chip, and may be formalized and automated.     

Optimization of the machining economics problem under the periodic control strategy

This paper presents a model for calculating the optimal cutting feed rate, spindle speed, and periodic control interval for a standalone cutting machine. The optimal cutting conditions are determined for the maximum expected 'profit rate' criterion, under the assumption that the Normal distribution function represents the tool-life distribution. When the cutting operation and the load/unload process are preformed automatically without any supervisor, it is not necessary to employ a full-time operator for the machine. Thus, we used the Periodic Control Strategy, under which the operator attends to the cutting machine only at predefined calendar times. We have developed an approximate model that was studied using simulations. The model appears to be very efficient.     

Optically Induced Cell Fusion Using Bispecific Nanoparticles

Redirecting the immune system to eliminate tumor cells is a promising alternative to traditional cancer therapies, most often requiring direct interaction between an immune system effector cell and its target. Herein, a novel approach for selective attachment of malignant cells to antigen‐presenting cells by using bispecific nanoparticles is presented. The engaged cell pairs are then irradiated by a sequence of resonant femtosecond pulses, which results in widespread cell fusion and the consequent formation of hybrid cells. The dual role of gold nanoparticles as conjugating agents and fusion promoters offers a simple yet effective means for specific fusion between different cells. This technology could be useful for a variety of in vitro and in vivo applications that call for selective fusion between cells within a large heterogenic cell population.     

Nonlinear Analysis of Masonry Arches Strengthened with Composite Materials

The nonlinear behavior of masonry arches strengthened with externally bonded composite materials is investigated. A finite-element (FE) formulation that is specially tailored for the nonlinear analysis of the strengthened arch is developed. The FE formulation takes into account material nonlinearity of the masonry construction and high-order kinematic relations for the layered element. Implementation of the above concept in the FE framework reduces the general problem to a one-dimensional nonlinear formulation in polar coordinates with a closed-form representation of the elemental Jacobian matrix (tangent stiffness). A numerical study that examines the capabilities of the model and highlights various aspects of the nonlinear behavior of the strengthened masonry arch is presented. Emphasis is placed on the unique effects near irregular points and the nonlinear evolution of these effects through the loading process. A comparison with experimental results and a discussion of the correlating aspects and the ones that designate needs of further study are also presented.     

Hybrid Proton and Electron Transport in Peptide Fibrils

Protons and electrons are being exploited in different natural charge transfer processes. Both types of charge carriers could be, therefore, responsible for charge transport in biomimetic self‐assembled peptide nanostructures. The relative contribution of each type of charge carrier is studied in the present work for fibrils self‐assembled from amyloid‐β derived peptide molecules, in which two non‐natural thiophene‐based amino acids are included. It is shown that under low humidity conditions both electrons and protons contribute to the conduction, with current ratio of 1:2 respectively, while at higher relative humidity proton transport dominates the conductance. This hybrid conduction behavior leads to a bimodal exponential dependence of the conductance on the relative humidity. Furthermore, in both cases the conductance is shown to be affected by the peptide folding state under the entire relative humidity range. This unique hybrid conductivity behavior makes self‐assembled peptide nanostructures powerful building blocks for the construction of electric devices that could use either or both types of charge carriers for their function.     

Correlation among microstructure,strength, and electrical conductivity of Cu-Ni-Be alloy

The UNS C17510 commercial Cu-Ni-Be alloy was heat treated in three different ways: AT, simple aging; HT, aging in the hardened condition; and TMT, a special thermo-mechanical treatment. It was found that in the electrical conductivity range of 50 to 60 pct IACS the TMT treatment results in a much higher yield strength than either the AT or the HT treatments. Three types of particles have been identified: relatively large primary beryllides, very small -γ precipitates, and small non-coherent nickel-rich beryllides (NRB). Based on measurements of the size distribution of NRB pre-cipitates and by means of an existing theoretical model, it was shown that these precipitates together with a dense dislocation network are responsible for the increased strength of the alloy follow-ing TMT.     

Free convection boundary-layer flow over horizontal plates and discs

Free convection flows near horizontal surfaces are discussed for those cases in which a similarity solution can be obtained. Particular cases considered are those of asymptotically large and vanishingly small Prandtl numbers. The solution for the relevant velocity, temperature and pressure functions has to be carried-out numerically. For the particular cases when the Prandtl number is either sufficiently large, or sufficiently small, this integration would yield general functions, no longer dependent on the Prandtl number. Numerical data are included.