Numerical simulation of heat transfer and hydrodynamics ring and V-shaped heat exchange intensifiers

© 2016, International Journal of Pharmacy and Technology. All rights reserved.An urgent task is the increase of thermal efficiency of pipes for heat exchangers. The greater efficiency of the pipes, the more compact heat exchangers can be created; its material consumption and cost will also reduce. The most common method is increasing the efficiency by applying surface heat exchange intensifiers. It is important to keep in mind that increasing the thermal efficiency by applying heat exchange intensifiers entails an increase of the hydraulic resistance of pipes. To create an effective intensifier we need to find the balance between the thermal efficiency growth and the hydraulic resistance growth. The results of numerical simulation of the process of heat transfer using a new kind of v-shaped intensifiers are presented in the work. A comparison of the thermal efficiency of v-shaped intensifiers with ring intensifiers and smooth pipes, and the comparison of the hydraulic resistance increase are given in the article. The research of hydrodynamic and heat exchange processes was carried out in turbulent regime within the range of Re numbers from 3000 to 40000 to assess the thermal-hydraulic efficiency of pipes in various flow regimes. The application of v-shaped intensifiers can improve thermal efficiency in the whole range of studies compared with ring intensifiers, at moderate growth of hydraulic resistance at low value of Re numbers

Nonlinearity Management in Higher Dimensions

In the present short communication, we revisit nonlinearity management of the time-periodic nonlinear Schrodinger equation and the related averaging procedure. We prove that the averaged nonlinear Schrodinger equation does not support the blow-up of solutions in higher dimensions, independently of the strength in the nonlinearity coefficient variance. This conclusion agrees with earlier works in the case of strong nonlinearity management but contradicts those in the case of weak nonlinearity management. The apparent discrepancy is explained by the divergence of the averaging procedure in the limit of weak nonlinearity management.Comment: 9 pages, 1 figure

Time-Dependent Invariants for Dirac Equation and Newton-Wigner Position Operator

For Dirac equation, operator-invariants containing explicit time-dependence in parallel to known time-dependent invariants of nonrelativistic Schr\"odinger equation are introduced and discussed. As an example, a free Dirac particle is considered and new invariants are constructed for it. The integral of motion, which is initial Newton-Wigner position operator, is obtained explicitly for a free Dirac particle. For such particle with kick modeled by delta-function of time, the time-depending integral, which has physical meaning of initial momentum, is found.Comment: LATEX,21 pages,submitted to Physica Script

Сибирский щит Волжской твердыни

On the fundamental work “The Siberian Shield of the Volga Stronghold”, telling about the contribution of the Siberians and the Far-Easterns to the defeat of Nazi invaders and their Hungarian, Romanian, Italian satellites and the Spanish “Blue Division” on the banks of Volga, the Great Russian River.О фундаментальном труде «Сибирский щит Волжской твердыни», повествующем о вкладе сибиряков и дальневосточников в разгром гитлеровских захватчиков и их венгерских, румынских, итальянских сателлитов и испанской «Голубой дивизии» на берегах великой русской реки Волги

Сибиряки - защитники и победители

Review of publication "Siberians in the battle for Moscow", which is part of the anthology "Tobolsk, and the whole of Siberia", published by the Public Charitable Foundation "Revival of Tobolsk."Обзор издания «Сибиряки в битве за Москву», входящего в состав альманаха «Тобольск и вся Сибирь», выпущенного Общественным благотворительным фондом «Возрождение Тобольска»

«К державной славе земли прибавив…»: история казачества в сибирском альманахе

On the release of volume XIV of the almanac “Tobolsk and all Siberia”, dedicated to the history of the Siberian Cossacks. The edition contains little-known facts and historical documents, prominent representatives of Cossack outlaws are also mentioned.Рассказывается о выпуске XIV тома альманаха «Тобольск и вся Сибирь», посвященного истории Сибирского казачества. В издании приводятся малоизвестные факты и исторические документы, упоминаются видные представители казацкой вольницы

«Сибирь обильна и полна сокровищ редких, благородных...»

The author tells about a new publishing project of the well-known Russian Maecenas and bibliophile Arcadiy Elfimov, continues to return forgotten book rarities to a modern reader, to literary miscellany “Tobolsk and all Siberia”, numbering 13 issues. The appendix in the form of restored library of the Siberian writers is added. The first four volumes have already been published. This project is a result of serious archeographic researches, which have revealed the new archives and documents.Рассказывается о новом издательском проекте известного российского мецената и библиофила Аркадия Елфимова, продолжающего возвращать современному читателю забытые книжные раритеты. К уже снискавшему славную репутацию альманаху «Тобольск и вся Сибирь», насчитывающему 13 выпусков, добавляется приложение в виде возрождаемой библиотеки сибирских писателей, первые четыре тома которой вышли в свет. Этот проект стал результатом серьезных археографических изысканий, выявивших новые архивные фонды и документы

Fast atomic transport without vibrational heating

We use the dynamical invariants associated with the Hamiltonian of an atom in a one dimensional moving trap to inverse engineer the trap motion and perform fast atomic transport without final vibrational heating. The atom is driven non-adiabatically through a shortcut to the result of adiabatic, slow trap motion. For harmonic potentials this only requires designing appropriate trap trajectories, whereas perfect transport in anharmonic traps may be achieved by applying an extra field to compensate the forces in the rest frame of the trap. The results can be extended to atom stopping or launching. The limitations due to geometrical constraints, energies and accelerations involved are analyzed, as well as the relation to previous approaches (based on classical trajectories or "fast-forward" and "bang-bang" methods) which can be integrated in the invariant-based framework.Comment: 10 pages, 5 figure