Some updates to the method for calculation of parameters of bottom trawl system

The method for calculation of geometric parameters of trawl system proposed by F.I. Baranov is analyzed. The calculation includes evaluation of spacer force and drag for all elements of trawl system and solution of transcendental equation to find a distance between the otter boards of bottom trawl. Special attention is paid to considering and enhancement of common techniques for determining force and geometric parameters of some elements of trawl system, with identifying the most appropriate ways. The calculations and experimental data are compared for a trawl system using the Scanmar equipment for monitoring of fishing gear. The updated model simulates more adequately the forming of bottom trawl geometry, therefore it can be used for assessment of the catch area during trawl surveys conducted by bottom trawls

Laserwire at the Accelerator Test Facility 2 with Sub-Micrometre Resolution

A laserwire transverse electron beam size measurement system has been developed and operated at the Accelerator Test Facility 2 (ATF2) at KEK. Special electron beam optics were developed to create an approximately 1 x 100 {\mu}m (vertical x horizontal) electron beam at the laserwire location, which was profiled using a 150 mJ, 71 ps laser pulse with a wavelength of 532 nm. The precise characterisation of the laser propagation allows the non-Gaussian transverse profiles of the electron beam caused by the laser divergence to be deconvolved. A minimum vertical electron beam size of 1.07 ${\pm}$ 0.06 (stat.) ${\pm}$ 0.05 (sys.) {\mu}m was measured. A vertically focussing quadrupole just before the laserwire was varied whilst making laserwire measurements and the projected vertical emittance was measured to be 82.56 ${\pm}$ 3.04 pm rad.Comment: 17 pages, 26 figures, submitted to Phys. Rev. ST Accel. Beam

Fast barrier-free switching in synthetic antiferromagnets

We analytically solve the Landau-Lifshitz equations for the collective magnetization dynamics in a synthetic antiferromagnet (SAF) nanoparticle and uncover a regime of barrier-free switching under a short small-amplitude magnetic field pulse applied perpendicular to the SAF plane. We give examples of specific implementations for forming such low-power and ultra-fast switching pulses. For fully optical, resonant, barrier-free SAF switching we estimate the power per write operation to be $\sim 100$ pJ, 10-100 times smaller than for conventional quasi-static rotation, which should be attractive for memory applications.Comment: 12 pages, 4 figure

Efficiency improvement of forest machinery exploitation

The purpose of this work was to develop a model of the interaction process between the wheeled forwarder and the soil of the cutting area, which allows evaluating the influence of soil conditions, the parameters of the wheeled forwarder, as well as load and number of cycles of its application, on the indicators of resistance and adhesion of the forwarder to the traction surface. Modeling results for 3-and 4-Axle forest machines with different load levels showed that for different soil categories, types of bodies, and tire sizes. The results of the approximation analysis enabled the derive of calculation formulas for estimating the propulsive coefficient and rut depth after the first passage depending on the values of load-bearing capacity, body load coefficient, wheel width, and soil deformation module. The proposed model can be used at laying down the skidding roads and its optimization not only in economic terms but also with respect to the environment as intensive harvesting operations lead to extensive soil destructions. The practical application of the results is expressed in increased performance capacities of wood skidding operations and minimization of costs for restoring the productivity of forest area. © 2020 Polish Society of Technical Diagnostics. All rights reserved

Some aspects of pot fishery on humpback shrimp <i>Pandalus hypsinotus</i> and its biological condition in the southern part of the subzone Primorye (Japan Sea) in autumn 2013

Data on productivity of pot fishery on humpback shrimp at the coast of Primorye are presented, actual in conditions of its trawl fishery ban in the northwestern Japan Sea. Biological parameters of the shrimp in the fishing season are considered, and dynamics of the catches is analyzed for one of the major fishing grounds. Species composition and abundance of by-catch in the shrimp pots are discussed. Dependence of the shrimp catch on options of the bite preparation is determined

БЫСТРОДЕЙСТВИЕ ВОЛОКОННО- ОПТИЧЕСКИХ СИСТЕМ

The authors study the issues of increasing performance of fiber-optics system of transmission via the growth of operating speed of elementary components of optoelectronics. They pay special attention to optical modulators of Mach–Zehnder. The researches on modulation characteristics permitted to formulate the requirements for the quality of fabrication of optical waveguides.Вопросы повышения эффективности волоконно-оптической системы передачи (ВОСП) за счет увеличения быстродействия элементной базы оптоэлектроники. Основное внимание уделено оптическим модуляторам Маха-Цендера. Исследования модуляционной характеристики позволили сформулировать требования к качеству изготовления оптических волноводов

Coherent Cherenkov radiation as an intense THz source

Diffraction and Cherenkov radiation of relativistic electrons from a dielectric target has been proposed as mechanism for production of intense terahertz (THz) radiation. The use of an extremely short high-energy electron beam of a 4th generation light source (X-ray free electron laser) appears to be very promising. A moderate power from the electron beam can be extracted and converted into THz radiation with nearly zero absorption losses. The initial experiment on THz observation will be performed at CLARA/VELA FEL test facility in the UK to demonstrate the principle to a wider community and to develop the radiator prototype. In this paper, we present our theoretical predictions (based on the approach of polarization currents), which provides the basis for interpreting the future experimental measurements. We will also present our hardware design and discuss a plan of the future experiment