Kinematics of Articulated Planar Linkages

This paper proposes a kinematics algorithm in screw coordinates for articulated linkages. As the screw consists of velocity and position variables of a joint, the solutions of the forward and inverse velocities are the functions of position coordinates and their time derivatives. The most prominent merit of this kinematic algorithm is that we only need the first order numerical differential interpolation for computing the acceleration. To calculate the displacement, we also only need the first order numerical integral of the velocity. This benefit stems from the screw the coordinates of which are velocity components. Both the forward and the inverse kinematics have the similar calculation process in this method. Through examples of planar open-chain linkage, single closed-chain linkage and multiple closed-chain linkage, the kinematics algorithm is validated. It is particularly fit for developing numerical programmers for forward and inverse kinematics in the same procedures, including the velocity, displacement and acceleration which provide the fundamental information for dynamics of the linkage.

One-loop renormalization in quantum gravity

This chapter demonstrates the basic methods of one-loop calculations in quantum gravity. Basing its discussion on the general results obtained in chapter 10, it first presents a detailed analysis of the gauge-fixing dependence of one-loop divergences in quantum general relativity and higher-derivative models of quantum gravity. After that, a detailed derivation of divergences in quantum general relativity is given, with the simplest parametrization of the quantum metric and minimal gauge fixing. One-loop divergences in the general (non-conformal) fourth-derivative quantum gravity are then derived in less detail. For a similar calculation in the superrenormalizable polynomial model (superrenormalizable gravity), the chapter just presents and discusses the final result.

Proposed A Permutation and Substitution Methods of Serpent Block Cipher

Block cipher technique is one of cryptography techniques to encrypt data block by block. The Serpent is one of AES candidates. It encrypts a 128-bit block by using 32 rounds of a similar calculation utilizing permutations and substitutions. Since the permutations and substitutions of it are static. Then this paper proposes dynamic methods for permutation, substitution and key generation based on chaotic maps to get more security. The proposed methods are analyzed and the results showed that they were able to exceed the weakness resulting from the use of static permutations and substitutions boxes in the original algorithm and also can reduce number of rounds and time usage compared with a classical Serpent block cipher algorithm

The Frenet Vector Fields and the Curvatures of the Natural Lift Curve

In this paper, Frenet vector fields, curvature and torsion of the natural lift curve of a given curve is calculated by using the angle between Darboux vector field and the binormal vector field of the given curve in 3/1 . Also, a similar calculation is made in 3/1 considering timelike or spacelike Darboux vector field.

Hardness and adhesive properties of (Cr, Mo) oxycarbide films on stainless steel via vapor deposition

A hexacarbonyl of chromium and molybdenum [(Cr, Mo) (CO)6] was used as an oxycarbide source for the coating on stainless steel 304 (SS304) at temperatures from 175 °C to 450 °C. Hardness of the films was determined from a microindentation technique through a similar calculation after Thomas (1987). Intrinsic hardnesses of the films formed at low and medium temperatures were determined to be 8.61 and 2.75 GPa, respectively. Both of them are larger than that of SS304 substrate, 1.75 GPa. Adhesive strength of the films was measured by the scratching test. The results reveal that the adhesive strengths of the films formed at low, medium, and high temperatures are 2.8 N, 37.6 N, and 36.0 N, respectively. Two different fracture modes after scratching were found for the films obtained at various temperature regions. A spalling-off type or a deformation failure with many cracks and deformation bands beside the striation was found.

NONSTANDARD MODEL COUPLINGS IN WWV VERTEX

Using the nonstandard model vertex for WWV coupling, the helicity amplitudes, differential cross-sections and total cross-sections for the process e+e−→W+W− as functions of κV and λV have been calculated, and compared with SM predictions. A similar calculation has also been done for the process eγ→Wνe.

SUPERCONDUCTIVITY DUE TO CHARGE DENSITY WAVE INSTABILITY IN Ba1−xKxBiO3 COMPOUNDS

Recent experiments seem to indicate that the superconductivity in Ba 1−x K x BiO 3 type compound occurs in the metallic state before its transformation to the charge density wave (CDW) state as the doping parameter x is reduced. Assuming the local breathing modes around Bi-atoms are responsible for both the CDW and superconducting states. We show that the superconducting transition temperature T c can be substantially enhanced as x approaches the CDW instability from the metallic side. Similar calculation has been carried out for a two-dimensional system and the results are in qualitative agreement with a recent Monte Carlo simulation.

Electronic structure of zinc phthalocyanine

The electronic structure of zinc phthalocyanine is investigated through MSXα computations and XPS experiments. Reasonable argeement is found between the qualitative structure of the molecular orbital diagram and the XPS spectrum. The visible spectrum is also discussed and the calculation is compared to previous semi-empirical computations. On the other hand, it is shown that a similar calculation on the zinc tetraazaporphyrin — selected as a model molecule — cannot be used to interpret the electronic properties of the phthalocyanine.

SPEED OF SOUND IN NUCLEAR MATTER AND SKYRME EFFECTIVE INTERACTIONS

Using a nuclear equation of state derived from a finite-temperature Green’s function method and the Skyrme effective interactions SkI, SkIII and SkM*, we have calculated the speed of sound in symmetric nuclear matter. For certain densities and temperatures, this speed is found to become super-luminous. Causal boundaries in the density-temperature plane are determined, and they indicate that SkM* is a more desirable effective interaction than SkI and SkIII. Comparison with a similar calculation by Osnes and Strottman is made.

Re-examination of the Kirkwood–Westheimer theory of electrostatic effects. II. Possible conformations of α,ω-amino-acids in aqueous solutions, as deduced from dissociation constants

The first and second dissociation constants of the ten homologous a, α,ω-amino-acids [Formula: see text] have been determined by a potentiometric method at different temperatures, and hence the thermodynamic parameters ΔG0, ΔH0, and ΔS0 were computed. Calculation by Kirkwood–Westheimer theory of ΔG10 for the first (carboxyl) dissociation, assuming the conformation of the polymethylene chain to be intermediate between the random-coil and the fully extended conformation, gives results in good agreement with experiment for the longer chains. A similar calculation of ΔG20 for the second (ammonium) dissociation gives results in fair agreement with theory for the very long chains (n = 7–10), but in disagreement for shorter chains. A tentative explanation based on electrostatic effects on hydration of the ammonium group is advanced.