A similarity criterion for forest growth curves

Comparison of forest growth curves has led many to the conclusion that there is a similarity between forest stands growing in different conditions. Here we treat the same subject from the viewpoint of similarity theory. Our goal is to form a dimensionless ratio of biophysical entities that could parameterize the diversity of forest growth curves. (Such ratios are called similarity criteria.) Pursuing this goal, we focus on the analogy between tree crown growth and atomic explosion. A blast wave is formed when the rate of energy release is much higher than the rate of energy dissipation. The difference between the rates of energy release and dissipation is the essence of this phenomenon. The essential feature of crown growth is the difference between the rates of non-structural carbohydrate supply and demand. Since the rate of supply is much higher than the rate of demand, the flow of non-structural carbohydrates achieves the tips of branches and enables the radial growth of crown. Proceeding from these ideas, we derived the similarity criterion which supposedly captures the “essence of growth” that emerges from the geometric similarity of tree crowns

Freedom of Navigation: Development of the Law of the Sea and Emerging Challenges

This keynote address was delivered at the Freedom of Navigation and the Law of the Sea workshop hosted by the Stockton Center for the Study of International Law at the U.S. Naval War College on May 18, 2017

Dynamics of automatic stations' descent in planetary atmospheres as means of measurement data control

Automatic stations descent in planetary atmospheres as means of measurement data contro

Random moves equation Kolmogorov-1934. A unified approach for description of statistical phenomena of nature

The paper by A.N. Kolmogorov 1934 "Random Moves", hereinafter ANK34, uses a Fokker-Planck-type equation for a 6-dimensional vector with a total rather than a partial derivative with respect to time, and with a Laplacian in the space of velocities. This equation is obtained by specifying the accelerations of the particles of the ensemble by Markov processes. The fundamental solution was used by A M Obukhov in 1958 to describe a turbulent flow in the inertial interval. Already recently it was noticed that the Fokker-Planck-type equation written by Kolmogorov contains a description of the statistics of other random natural processes, earthquakes, sea waves, and others. This theory, containing the results of 1941, paved the way for more complex random systems containing enough parameters to form an external similarity parameter. This leads to a change in the characteristics of a random process, for example, to a change in the slope of the time spectrum, as in the case of earthquakes and in a number of other processes (sea waves, cosmic ray energy spectrum, flood zones during floods, etc.). A review of specific random processes studied experimentally provides a methodology for how to proceed when comparing experimental data with the ANK34 theory. Thus, empirical data illustrate the validity of the fundamental laws of probability theory.Comment: 23 pages, 4 figure

Convection of viscous fluids: Energetics, self-similarity, experiments, geophysical applications and analogies

The main results were the formulas for the mean convection velocities, of a viscous fluid and for the mean temperature difference in the bulk of the convecting fluid. These were obtained: by scaling analysis of the Boussinesq equations, by analysis of the energetics of the process, and by using similarity and dimensional arguments. The last approach defines the criteria of similarity and allows the proposition of some self-similarity hypotheses. By several simple new ways, an expression for the efficiency coefficient gamma of the thermal convection was also obtained. An analogy is pointed out between non-turbulent convection of a viscous fluid and the structure of turbulence for scales less than Kolmogorov's internal viscous microscale of turbulence

Оброблення даних барометричного альтіметра

The paper deals with features of measurement of an altitude for unmanned aerial vehicles.Analysis of altitude sensors characteristics and the grounded choice of the low cost barometric altimeteris carried out. The procedure of data processing is developed. Filtration of data by means of theButterwort filter is carried out. Simulation results prove efficiency of the developed procedure of dataprocessingРассмотрены особенности измерения высоты на борту беспилотных летательных аппаратов. Выполнены анализ характеристик датчиков высоты и обоснованный вибор барометрического альтиметра низкой стоимости. Разработана процедура обработки информации. Выполнена фильтрация информации при помощи фильтра Баттерворта. Результаты моделирования подтверждают эффективность предложенной процедуры обработки информацииРозглянуто особливості вимірювання висоти на борту безпілотних літальних апаратів. Виконано аналіз характеристик датчиків висоти та обгрунтовано вибір низьковартісного барометричного альтиметра. Розроблено процедуру оброблення інформації. Виконано фільтраціію інформації за допомогою фильтра Баттерворта. Результати моделювання підтверджують ефективність запропонованої процедури оброблення інформаці

Reduced-mobility layers with high internal mobility in poly(ethylene oxide)-silica nanocomposites

© 2017 Author(s). A series of poly(ethylene oxide) nanocomposites with spherical silica was studied by proton NMR spectroscopy, identifying and characterizing reduced-mobility components arising from either room-temperature lateral adsorption or possibly end-group mediated high-temperature bonding to the silica surface. The study complements earlier neutron-scattering results for some of the samples. The estimated thickness of a layer characterized by significant internal mobility resembling backbone rotation ranges from 2 nm for longer (20 k) chains adsorbed on 42 nm diameter particles to 0.5 nm and below for shorter (2 k) chains on 13 nm particles. In the latter case, even lower adsorbed amounts are found when hydroxy endgroups are replaced by methyl endgroups. Both heating and water addition do not lead to significant changes of the observables, in contrast to other systems such as acrylate polymers adsorbed to silica, where temperature- and solvent-induced softening associated with a glass transition temperature gradient was evidenced. We highlight the actual agreement and complementarity of NMR and neutron scattering results, with the earlier ambiguities mainly arising from different sensitivities to the component fractions and the details of their mobility