On the Length of the Relaxation Zone of Ionization Behind a Strong Shock Wave Front in the Air

Relaxation zone behind strong shock wave front in ai

Application of dynamic priorities for controlling the characteristics of a queuing system

This paper considers the development and modification of an imitation model of a queuing system. The initial model uses the laws of control (discipline of expectation and service) with mixed priorities. The work investigates the model with three types of entities (absolute priority, relative priority and priority-free ones) in the regime of overload, i.e. a system with losses. Verification and validation of the created imitation model confirmed its adequateness and accuracy of received results. The application of dynamic priorities for changing the laws of model control substantially alters certain system characteristics. The creation of the model in MatLab Simulink environment with the use of SimEvents and Stateflow library modules allowed creating a fairly complex queuing system and obtain new interesting results

Application of dynamic priorities for controlling the characteristics of a queuing system

This paper considers the development and modification of an imitation model of a queuing system. The initial model uses the laws of control (discipline of expectation and service) with mixed priorities. The work investigates the model with three types of entities (absolute priority, relative priority and priority-free ones) in the regime of overload, i.e. a system with losses. Verification and validation of the created imitation model confirmed its adequateness and accuracy of received results. The application of dynamic priorities for changing the laws of model control substantially alters certain system characteristics. The creation of the model in MatLab Simulink environment with the use of SimEvents and Stateflow library modules allowed creating a fairly complex queuing system and obtain new interesting results

Kaon pair production in proton-nucleus collisions at 2.83 GeV kinetic energy

The production of non-phi K+K- pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag, and Au targets has been investigated using the COSY-ANKE magnetic spectrometer. The K- momentum dependence of the differential cross section has been measured at small angles over the 0.2--0.9 GeV/c range. The comparison of the data with detailed model calculations indicates an attractive K- -nucleus potential of about -60 MeV at normal nuclear matter density at a mean momentum of 0.5 GeV/c. However, this approach has difficulty in reproducing the smallness of the observed cross sections at low K- momenta.Comment: 7 pages, 5 figures, 1 tabl

The production of K+K- pairs in proton-proton collisions at 2.83 GeV

Differential and total cross sections for the pp -> ppK+K- reaction have been measured at a proton beam energy of 2.83 GeV using the COSY-ANKE magnetic spectrometer. Detailed model descriptions fitted to a variety of one-dimensional distributions permit the separation of the pp -> pp phi cross section from that of non-phi production. The differential spectra show that higher partial waves represent the majority of the pp -> pp phi total cross section at an excess energy of 76 MeV, whose energy dependence would then seem to require some s-wave phi-p enhancement near threshold. The non-phi data can be described in terms of the combined effects of two-body final state interactions using the same effective scattering parameters determined from lower energy data.Comment: 12 pages, 12 figures, 3 table

Momentum dependence of the phi-meson nuclear transparency

The production of phi mesons in proton collisions with C, Cu, Ag, and Au targets has been studied via the phi -> K+K- decay at an incident beam energy of 2.83 GeV using the ANKE detector system at COSY. For the first time, the momentum dependence of the nuclear transparency ratio, the in-medium phi width, and the differential cross section for phi meson production at forward angles have been determined for these targets over the momentum range of 0.6 - 1.6 GeV/c. There are indications of a significant momentum dependence in the value of the extracted phi width, which corresponds to an effective phi-N absorption cross section in the range of 14 - 21 mb.Comment: 9 pages, 5 figure

Comparison of inclusive K+ production in proton-proton and proton-neutron collisions

The momentum spectra of K+ produced at small angles in proton-proton and proton-deuteron collisions have been measured at four beam energies, 1.826, 1.920, 2.020, and 2.650 GeV, using the ANKE spectrometer at COSY-Juelich. After making corrections for Fermi motion and shadowing, the data indicate that K+ production near threshold is stronger in pp- than in pn-induced reactions. However, most of this difference could be made up by the unobserved K0 production in the pn case.Comment: 6 pages, 4 figures, Submitted to PR

Эффективность электрохимическом мембранной очистки технологических растворов от сульфата меди и тринатрийфосфата

The paper considers the potential practical application of an electrochemical membrane method in the process of copper sulfate and trisodium phosphate removal from industrial water. The research objects were process solutions containing copper sulfate and trisodium phosphate and semipermeable polymeric membranes with various selective permeability characteristics. The study covers the effect that the transmembrane parameters of electromembrane separation have on the main kinetic characteristics of MGA-95P and OPM-K membranes in the process of copper smelting production water treatment. Approximation expressions were obtained to calculate membrane rejection rate depending on the physicochemical basis of the semipermeable membrane polymer, transmembrane pressure as well as process solution concentration and temperature. Empirical coefficients were determined to calculate and predict rejection rate values that can be used in the design of laboratory, pilot and industrial units used in the separation, treatment and concentration of industrial and waste water. The mathematical model of mass transfer was developed for electrochemical membrane separation taking into account assumptions made based on the solutions of the Nernst—Planck and Poisson—Boltzmann equations. This model allows for process physical description and calculations of concentration fields in the intermembrane channel and concentration changes in permeate and retentate lines. The mathematical model was checked for adequacy by comparing experimental data on retention rate with theoretical values where discrepancies between the experimental and theoretical data were within the limits of the experimental error and the error of calculated values.Рассмотрены возможности практического применения электрохимического мембранного метода в процессе очистки технологических вод от сульфата меди и тринатрийфосфата. Объектами исследования были технологические растворы, содержащие сульфат меди и тринатрийфосфат, и полупроницаемые мембраны полимерного вида с различными селективно-проницаемыми характеристиками. Изучено влияние трансмембранных параметров проведения электромембранного процесса разделения на основные кинетические характеристики мембран МГА-95П и ОПМ-К при очистке технологических вод медеплавильного производства. Получены аппроксимационные выражения для расчета коэффициента задержания мембраны в зависимости от физико-химической основы полимера полупроницаемой мембраны, величины трансмембранного давления, концентрации и температуры технологического раствора. Определены эмпирические коэффициенты, позволяющие рассчитывать и прогнозировать значения коэффициента задержания, которые могут быть использованы в проектировании лабораторных, пилотных и промышленных установок, применяемых в производственных процессах разделения, очистки и концентрирования технологических и сточных вод. Разработана математическая модель массопереноса электрохимического мембранного разделения с учетом принятых допущений на основе решений уравнений Нернста—Планка и Пуассона—Больцмана, позволяющая физически описать процесс и рассчитать поля концентраций в межмембранном канале и изменения концентраций в трактах пермеата и ретентата. Проведена проверка адекватности математической модели путем сравнения экспериментальных данных по коэффициенту задержания с его теоретическими значениями. Расхождение между ними оказалось в пределах ошибки эксперимента и погрешности расчетных величин