Contact tracking algorithms in case of the omni-directional wheel rolling on the horizontal surface

Multibody System Dynamics - An omni-wheel is defined as a wheel having rollers along its rim. Vehicles with omni-wheels are able to maneuver in any direction. For modeling the dynamics of...     

Standard apparatus for measuring polarization mode dispersion in fiber-optic data transmission systems

Methods and instruments for ensuring the uniformity of polarization mode dispersion measurements in fiber-optic data transmission systems are described. The results of the development of a standard measuring instrument and working standards of the unit of dispersion are presented. The results of metrological investigations of a standard measuring instrument are also given.     

Development and application of setup for ac magnetic field in neutron scattering experiments

We report on a new setup developed for neutron scattering experiments in periodically alternating magnetic fields at the sample position. The assembly consisting of rf generator, amplifier, wide band transformer, and resonance circuit. It allows to generate homogeneous ac magnetic fields over a volume of a few cm(3) and variable within a wide range of amplitudes and frequencies. The applicability of the device is exemplified by ac polarized neutron reflectometry (PNR): a new method established to probe remagnetization kinetics in soft ferromagnetic films. Test experiments with iron films demonstrate that the ac field within the accessible range of frequencies and amplitudes produces a dramatic effect on the PNR signal. This shows that the relevant ac field parameters generated by the device match well with the scales involved in the remagnetization processes. Other possible applications of the rf unit are briefly discussed.     

National primary special standard for the unit of chromatic dispersion in optical fibers

The national primary special standard for the unit of chromatic dispersion in optical fibers, a national verification scheme, and results of metrological studies of the standard are described.     

Three-dimensional electrospun alginate nanofiber mats via tailored charge repulsions

The formation of 3D electrospun mat structures from alginate-polyethylene oxide (PEO) solution blends is reported. These unique architectures expand the capabilities of traditional electrospun mats for applications such as regenerative medicine, where a scaffold can help to promote tissue growth in three dimensions. The mat structures extend off the surface of the flat collector plate without the need of any modifications in the electrospinning apparatus, are self-supported when the electric field is removed, and are composed of bundles of nanofibers. A mechanism for the unique formations is proposed, based on the fiber-fiber repulsions from surface charges on the negatively charged alginate. Furthermore, the role of the electric field in the distribution of alginate within the nanofibers is discussed. X-ray photoelectron spectroscopy is used to analyze the surface composition of the electrospun nanofiber mats and the data is related to cast films made in the absence of the electric field. Further techniques to tailor the 3D architecture and nanofiber morphology by changing the surface tension and relative humidity are also discussed.     

Towards FE-simulation based production planning and development

To remain competitive in times of unstable markets and shrinking sales, automotive manufacturers are under pressure to decrease the product development time. Especially, the time for planning of production steps and processes is strictly limited. The numerical simulation of production processes can help to get insight into the parts’ behavior and properties and to evaluate the feasibility of the production steps. In this paper the role and application of the welding simulation for the production planning is discussed. The computed welding distortion can be taken into account before the forming tools are constructed and the first sheet parts are produced. Hence, many problems occurring during the assembly of welded parts can be identified and avoided and the number of prototypes can be reduced.     

Standard equipment for instruments for the measurement of chromatic dispersion in fiber-optic information transmission systems

A technique and procedure for the development of standard equipment for instruments used in the measurement of chromatic dispersion in fiber-optic information transmission systems are described. An analysis of the errors of the standard equipment is presented. Results of studies of the standard equipment and working standard of chromatic dispersion are also presented.     

The RED-100 two-phase emission detector

The RED-100 experimental setup, which is designed to detect elastic coherent neutrino scattering off xenon nuclei, is described. One specific feature of this setup is the possibility of using it in above ground experiments. The setup is based on the RED-100 two-phase emission detector in which liquid xenon is used as a working medium for detection of rare events. The results of the technical run with the setup are presented. These are the evidence of the normal operation of all systems and the readiness of the setup for carrying out an experiment.     

Utilization of new substrate materials for FPP fabric for Petryanov filters

The results-of an investigation of the possibility of using spanbond material and technical coarse fabric as substrates for preparing FPP-15-1.5 fabric for Petryanov filters are presented. It is shown that the technical coarse fabric possesses the most acceptable properties. The results of this work have been adopted in the pilot production of Petryanov filters at the Industrial Association “Mayak”. 6 tables, 8 references. Industrial Association “Mayak”. Translated from Atomnaya énergiya, Vol. 87, No. 4, pp. 261–266, October, 1999.