35 research outputs found
Suppression of flow pulsation activity by relaxation process of additive effect on viscous media transport
The article presents the analysis of the processes occurring together with the turbulent transfer of impulse in mixture of hydrocarbon fluid and polymer solutions (anti-turbulent additives). The study evaluates complex shear flows by popular theoretical and practical methods. Understanding of hydrodynamic and dissipative effects of laminar-turbulent transition tightening and turbulence suppression is provided. The peculiarities of "thin" flow structure in pipeline zones with complex shape walls are evaluated. Recommendations to forecast the local flow parameters, calculation of hydraulic resistance are given
Development of mathematical model of the system of small businesses
The purpose of this work is to develop the model and quantitative parameters of the system of small enterprises. The processes of small business development should be identified, formalized and presented in the form of a mathematical model, allowing the use of forecasting and regulation of the system of small enterprises. Mathematical and statistical research of quantitative changes in the small business system under the influence of various external factors. The indicators most adequately reflecting small business development have been established. External factors that have a predominant influence on the development of small businesses are identified. A mathematical model of a small business was developed. The tools of the conducted research can be used in different countries to improve the level of regulation and forecasting of the system of small enterprises. Developed a mathematical model for development of the system of small enterprises
Multiple-core-hole resonance spectroscopy with ultraintense X-ray pulses
Understanding the interaction of intense, femtosecond X-ray pulses with heavy
atoms is crucial for gaining insights into the structure and dynamics of
matter. One key aspect of nonlinear light-matter interaction was, so far, not
studied systematically at free-electron lasers -- its dependence on the photon
energy. Using resonant ion spectroscopy, we map out the transient electronic
structures occurring during the complex charge-up pathways. Massively hollow
atoms featuring up to six simultaneous core holes determine the spectra at
specific photon energies and charge states. We also illustrate how the
influence of different X-ray pulse parameters that are usually intertwined can
be partially disentangled. The extraction of resonance spectra is facilitated
by the fact that the ion yields become independent of the peak fluence beyond a
saturation point. Our study lays the groundwork for novel spectroscopies of
transient atomic species in exotic, multiple-core-hole states that have not
been explored previously.Comment: Supplementary information is include
Electronic Quantum Coherence in Glycine Molecules Probed with Ultrashort X-ray Pulses in Real Time
Structural changes in nature and technology are driven by charge carrier
motion. A process such as charge-directed reactivity that can be operational in
radiobiology is more efficient, if energy transfer and charge motion proceeds
along well-defined quantum mechanical pathways keeping the coherence and
minimizing dissipation. The open question is: do long-lived electronic quantum
coherences exist in complex molecules? Here, we use x-rays to create and
monitor electronic wave packets in the amino acid glycine. The outgoing
photoelectron wave leaves behind a positive charge formed by a superposition of
quantum mechanical eigenstates. Delayed x-ray pulses track the induced
electronic coherence through the photoelectron emission from the sequential
double photoionization processes. The observed sinusoidal modulation of the
detected electron yield as a function of time clearly demonstrates that
electronic quantum coherence is preserved for at least 25 femtoseconds in this
molecule of biological relevance. The surviving coherence is detected via the
dominant sequential double ionization channel, which is found to exhibit a
phase shift as a function of the photoelectron energy. The experimental results
agree with advanced ab-initio simulations.Comment: 54 pages, 11 figure
Resonance-Enhanced Multiphoton Ionization in the X-Ray Regime
Here, we report on the nonlinear ionization of argon atoms in the short wavelength regime using ultraintense x rays from the European XFEL. After sequential multiphoton ionization, high charge states are obtained. For photon energies that are insufficient to directly ionize a 1s electron, a different mechanism is required to obtain ionization to Ar17+. We propose this occurs through a two-color process where the second harmonic of the FEL pulse resonantly excites the system via a 1s -> 2p transition followed by ionization by the fundamental FEL pulse, which is a type of x-ray resonance-enhanced multiphoton ionization (REMPI). This resonant phenomenon occurs not only for Ar16+, but also through lower charge states, where multiple ionization competes with decay lifetimes, making x-ray REMPI distinctive from conventional REMPI. With the aid of state-of-the-art theoretical calculations, we explain the effects of x-ray REMPI on the relevant ion yields and spectral profile
Interferometry on small quantum systems at short wavelength
The present work concentrates on prototypical studies of light-induced correlated manybodydynamics in complex systems. In its course a reflective split-and-delay unit (SDU)for phase-resolved one-color pump-probe experiments with gas phase samples using VUV–XUV laser pulses was built. The collinear propagation of pump and probe pulses is ensuredby the special geometry of the SDU and allows to perform phase-resolved (coherent)autocorrelation measurements. The control of the pump-probe delay with attosecondprecision is established by a specially developed diagnostic tool based on an in-vacuumwhite light interferometer that allows to monitor the relative displacement of the SDU reflectorswith nanometer resolution. Phase-resolved (interferometric) pump-probe experimentswith developed SDU require spatially-resolved imaging of the ionization volume.For this an electron–ion coincidence spectrometer was built. The spectrometer enablescoincident detection of photoionization products using velocity map imaging (VMI) techniquefor electrons and VMI or spatial imaging for ions. In first experiments using thedeveloped SDU and the spectrometer in the ion spatial-imaging mode linear field autocorrelationof free-electron laser pulses at the central wavelength of 38 nm was recorded.A further focus of the work were energy- and time-resolved resonant two-photonionization experiments using short tunable UV laser pulses on C60 fullerene. The experimentsdemonstrated that dipole-selective excitation on a timescale faster than thecharacteristic intramolecular energy dissipation limits the number of accessible excitationpathways and thus results in a narrow resonance. Time-dependent one-color pumpprobestudy showed that nonadiabatic (vibron) coupling is the dominant energy dissipationmechanism for high-lying electronic excited states in C60
Public-private partnerships as a promising tool to implement integration development strategy (on the example of tourism and resorts)
In scientific work analyzed the development of tourism Ukraine (travel and hotel services, spa facilities). The content of public-private partnerships. Public-private partnership deals in the system integration strategy implementation tools. The state of public-private partnership in tourism and resorts investigated. Suggestions on improving public policies to support the development of tourism market. Subject of research - theoretical and methodological and scientific and practical basis of public-private partnerships in the context of integration development strategy. The purpose of the article - submit proposals on organization of state support of tourism, hotel service and spa management capabilities using a public-private partnership as a tool for implementing integration strategies of enterprises. The study used general scientific and specific methods and techniques of research - induction and deduction, analysis and synthesis, abstraction scientific, economic modeling, method of expert evaluations, formal method (analysis of texts of regulations). A key result of the study is theoretical and methodological generalizations modern approaches to building public-private partnership in tourism as a tool for implementing an integration strategy. Field of application - State regulation of tourism, tourism economics, business economics, strategic planning, investment management activities. Key conclusions. Public-private partnerships should be considered as a special tool for the implementation of the integration strategy. It is necessary to develop a methodology (methodical approach) of public-private partnership in tourism, especially in the area of concession, which will ensure greater involvement in the process of local government. It is advisable to provide for a mechanism that allows the subjects of public-private partnership to get local resources on concessional terms (for example, when paying water or electricity). You should also provide that the guarantees for concession agreements may provide state represented by the Government of Ukraine or other specially authorized executive body that will increase the interest of potential investors. For subjects of public-private partnership should provide a number of preferences, especially tax benefits. Public-private partnership in the tourism sector can solve many encountered problems at the moment. The implementation of this partnership can be solved by building comprehensive tourism centers based on historical, cultural, archaeological and natural attractions
Оцінювання безвідмовності металевих водопровідних труб
Calculation of reliability of water supply facilities cannot be performed if data on the reliability of separate elements are missing. One of the ways to obtain data on the reliability of elements is an analysis of statistical data on failures. In order to establish quantitative indicators of reliability of water supply networks, we analyzed statistical data on damage to water pipes in the city of Kremenchuk, Poltava region (Ukraine). The time coverage of data analyzed on the failures of the cast-iron and steel pipes with diameter of 50...300 mm was 7 years. We found the main causes of failures: for the cast-iron pipes – cement outlet from bell joints (68 %); for the steel pipes – transverse fistulas (71 %). The mean value of specific failure rate parameter and its interval estimates are calculated. The weighted average value of specific failure rate parameter, regardless of the diameter is: 1/year·km (cast iron pipes) and 1/year·km (steel pipes). Based on analysis of the received results, we built dependence graphs of specific failure rate parameter on the diameter of a pipeline. They demonstrated that with an increase in the diameter, specific failure rate parameter decreases. The obtained dependences allow us to calculate reliability indicators for other assortments of diameters of pipes. The data recieved might be useful for calculating the failure free operation of water supply systems, which determine reliability of water supply to consumers.Исследованы причины отказов и значения удельного параметра потока отказов металлических водопроводных труб. Анализ статистических данных об отказах позволил построить зависимости удельного параметра потока отказов от диаметра трубопровода. Выполнен сравнительный анализ полученных данных и разработаны соответствующие выводы и предложения. Полученные данные полезны для расчетов надежности систем водоснабженияДосліджено причини відмов та значення питомого параметра потоку відмов металевих водопровідних труб. Аналіз статистичних даних щодо відмов дозволив побудовати залежності питомого параметра потоку відмов від діаметра трубопровода. Виконано порівняльний аналіз отриманих даних та розроблені відповідні висновки та пропозиції. Отримані дані корисні для розрахунків надійності систем водопостачанн
Influence of single physical loads of different intensity on the secretory activity of athletes blood neutrophils and monocytes
The article studies the impact of one-time physical activity of varying intensity on the secretory activity of neutrophils and monocytes in the blood of athletes of different sports specialization. Found that a single physical load average and peak levels experienced by athletes involved in aerobics, football and ran middle distance, cause a similar decrease in the expression of the secretory activity of neutrophils and monocytes in the blood, which is a decrease in the secretion of IL-1β, IL-6, IL-8, TNF-α and αIFN. Single physical loads threshold adverse effect on the functional activity of neutrophils and monocytes in athletes of different specialization do not have