Artificial Obstacles Research Articles

Показники виконання загальноконтрольної вправи на єдиній смузі перешкод курсантами під час проходження первинної підготовки

Purpose: to determine the level of the results of the exercise "obstacle course" students of the National Academy of the National Guard of Ukraine, identify common mistakes. Material and Methods: the study involved 46 students of the first year, which took basic training. We used the following methods: theoretical analysis and synthesis of scientific and instructional materials, teacher observation, testing, peer review, methods of mathematical statistics. Results: it was noted that the classes with students to overcome the single obstacle course aimed at the development and improvement of skills in overcoming the artificial and natural obstacles, throwing grenades and performing special moves and actions, development of speed and speed strength endurance, improving skills for collective action on the background strenuous exercise, nurturing self-confidence, courage and determination. The study revealed that the students specialty "Management of the actions of special forces" demonstrate better endurance than the students specialty "Automobiles and automobile industry." Compared with the regulations given in the Manual of physical training and sports of Interior Troops of Ukraine, the data correspond to the evaluation "below satisfactory". With the help of teacher observations and peer review were identified common mistakes that allow the cadets during the passage of the obstacle. Conclusions: the characteristics of the obstacle course: the time, the number of hitting the target and typical errors will improve the physical fitness of students in subsequent studies.

Experimental determination of the performance characteristics of an undulating submerged obstacle

This study reports physical experiments conducted with various combinations of undulating breakwaters under various wave conditions. The preliminary analysis consists of wave attenuation characteristics and efficiency of various combinations of sinusoidal breakwaters estimated by the transmittance, the variation in reflectance and loss coefficient, and the optimisations of a variety of sinusoidal breakwaters. The interaction of surface waves scattered by undulating ocean floor topography, such as sinusoidal bars, is of fundamental importance to sediment transportation. Thus, this study investigates the characteristics of multi-array impermeable sinusoidal submerged breakwaters experimentally. The interaction between waves and the obstacles are also investigated using the reflection coefficient, transmitted coefficient, and attenuation of wave energy. Most of the related investigations conducted theoretically and experimentally for the predictions of the propagation of water waves over the undulating ocean floor topography have focused on the problems of Bragg resonance. Specific parameters could be suitably chosen to control the resonance; composite artificial obstacles with specific parameters, which reduced the intensity of transmitted waves, may be used to protect beaches. Therefore, this study discusses the properties of the reflection coefficient of the sinusoidal breakwaters, the attenuation caused by the varying combinations of submerged obstacles, the effectiveness of wave attenuation, and the optimisation of the disposition of sinusoidal breakwaters.

INTELLECTUAL MIGRATION AS AN ISSUE OF CONTEMPORARY EDUCATION IN UKRAINE

This article discusses the causes and consequences of intellectual migration, brain drain, or the migration of Ukrainian scientists and educators from Ukraine. Causes for brain drain are: lack of reforms in education and science; low public spending on science and education; no conditions for work; the artificial obstacles for obtaining foreign grants and scholarships; no material and housing conditions; no moral or psychological freedom; no decent wages. Consequences of brain drain are: lack of reforms in the state; the significant lag in education, science, and in socio-economic and cultural areas; isolation from worldwide innovation and progress; political and socio-economic crisis; loss the status of the scientific country. Also this paper examines the dynamic of the reduction in the number of scientists from 1990-2012. The conclusions of the study are assumptions about the negative consequences of the current situation in the Ukrainian education and science system for Ukraine's future. We are sure that only real and consistent reforms of science and education can protect the Ukrainian system of education and science from irreversible processes. The country needs real reforms that could accumulate the human capital of Ukrainian scientists and educators through the creation of reasonable living and working conditions for them inside the country, not abroad. Otherwise, Ukraine could lose its status as a scientific state.

Proton-Coupled Electron Transfers: pH-Dependent Driving Forces? Fundamentals and Artifacts

Besides its own interest, tryptophan oxidation by photogenerated Ru complexes is one of the several examples where concerted proton-electron transfer (CPET) to water as proton acceptor endowed with a pH-dependent driving force has been invoked to explain the data. Since this notion is contrary to the very basic principles of chemical physics, it was interesting to attempt uncovering the source of this contradiction with an easily accessible substrate. Careful examination of the oxidation of the tryptophan (ethyl ester derivative) bearing a NH3(+)/NH2 group showed that there is no trace of such an unconventional H2O-CPET with a pH-dependent driving force. The reaction mechanism simply consists, with both the NH3(+) acid and NH2 basic forms of the tryptophan derivative, in a rate-determining electron-transfer step followed by deprotonation steps. The same is true with the ethyl ester-methyl amide derivative of tryptophan, whose behavior is even simpler since the molecule does not bear an acid-base group. No such unconventional H2O-CPET was found with phenol, another easily accessible substrate. It may thus be inferred that the same applies to less easily available systems in which electron transfer occurs intramolecularly. These observations help to rid the road of such artificial obstacles and improve present models of H2O-CPET reactions, a landmark towards the understanding of the role of water chains in natural systems.

OpenFOAM을 이용한 대규모 환경재현 시스템 내에서의 환경변수 제어 시뮬레이션

The feasibility of a unique greenhouse, named as Gradient Biome, is now being examined extensively in the University of Tokyo. It is a large chamber (length:200m, width:50m, height:40m) in which the weather, such as temperature and humidity, of the tropical zone through to that of the frigid zone on the earth is reproduced with continuous gradient. In the Gradient Biome, ecosystems (mainly plants) corresponding to each weather are introduced and the possible responses of this ecosystems to the expected global warming are to be observed. Since one of the expected responses is the shift of the ecosystem(s) toward the region of suitable environment, there should be no artificial obstacles, which can prevent the shift, inside the Biome. This requirement is not so easy to be satisfied since the environment tends to be homogeneous. This paper presents the results of the numerical studies conducted to find the ways of how the temperature and humidity in the Gradient Biome could be reproduced. One of the contributed solvers of OpenFOAM, which is an open source physics simulation code, was modified and used for the numerical simulations.

Do the visual conditions at the point of escape affect European sea bass escape behavior?

European sea bass (Dicentrarchus labrax), an important species for the Mediterranean aquaculture industry, has been reported to escape from sea cage installations. Fish escapes are caused mainly by operational and technical failures that eventually result into a creation of a tear. Escapees may interact with wild stocks through interbreeding, transfer of pathogens and competition for food. The aim of this study was to examine at which extent the presence of a visible obstacle close to a tear on the net have an influence on sea bass propensity to escape. Fish were initially confined into small sea cages, with a tear at one side. The escape behavior was tested under experimental conditions. It is clearly demonstrated that sea bass was able to locate a tear on the net pen, immediately after its appearance. Crossings occurred in all cages, in singles or in a series of up to seven individuals. The presence of an obstacle close to the net tear altered the escape behavior of D. labrax resulting in a delay that eventually reduced the escape rate. Concluding, it is highly recommended that sea bass cages should be kept internally the culture array. Furthermore, the placement of artificial obstacles close to the sea cages could be an efficient practice that mitigates the escape risk after severe environmental conditions.

Do the visual conditions at the point of escape affect European sea bass escape behavior?

European sea bass (Dicentrarchus labrax), an important species for the Mediterranean aquaculture industry, has been reported to escape from sea cage installations. Fish escapes are caused mainly by operational and technical failures that eventually result into a creation of a tear. Escapees may interact with wild stocks through interbreeding, transfer of pathogens and competition for food. The aim of this study was to examine at which extent the presence of a visible obstacle close to a tear on the net have an influence on sea bass propensity to escape. Fish were initially confined into small sea cages, with a tear at one side. The escape behavior was tested under experimental conditions. It is clearly demonstrated that sea bass was able to locate a tear on the net pen, immediately after its appearance. Crossings occurred in all cages, in singles or in a series of up to seven individuals. The presence of an obstacle close to the net tear altered the escape behavior of D. labrax resulting in a delay that eventually reduced the escape rate. Concluding, it is highly recommended that sea bass cages should be kept internally the culture array. Furthermore, the placement of artificial obstacles close to the sea cages could be an efficient practice that mitigates the escape risk after severe environmental conditions.

Performance assessment of GPS/GLONASS single point positioning in an urban environment

In signal-degraded environments such as urban canyons and mountainous area, many GNSS signals are either blocked or strongly degraded by natural and artificial obstacles. In such scenarios standalone GPS is often unable to guarantee a continuous and accurate positioning due to lack (or the poor quality) of signals. The combination of different GNSSs could be a suitable approach to fill this gap, because the multi-constellation system guarantees an improved satellite availability compared to standalone GPS, thus providing enhanced accuracy, continuity and integrity of the positioning. The present GNSSs are GPS, GLONASS, Galileo and Beidou, but the latter two are still in the development phase. In this work GPS/GLONASS systems are combined for single point positioning and their performance are assessed for different configurations. Using GPS/GLONASS multi-constellation implies the addition of an additional unknown, i.e. the intersystem time scale offset, which requires a sacrifice of one measurement. Since the intersystem offset is quasi-constant over a short period, a pseudo-measurement can be introduced to compensate the sacrifice. The benefit after adding a pseudo-measurement has been demonstrated in a vehicular test.

勾配方向の双対性とフラクタル次元を用いた細長い人工遮蔽物の検出

勾配方向の双対性とフラクタル次元を用いた細長い人工遮蔽物の検出

Field tests using radioactive matter 2

Results of field tests with explosive dispersal of a radioactive substance (RaS) are presented. The paper deals with tests exploiting artificial obstacles as a continuation and expansion of the tests used in this study performed in free area described previously. The essential goal of the tests was to estimate the distribution of the released RaS in the case of intentional abuse of radioactive sources and to get a set of data applicable to testing physical or mathematical models of propagation. Effects of different geometrical and meteorological conditions on the distribution of dispersed RaS were studied via the assessment of dose rate, surface and volume activities, aerosol mass and activity aerodynamic diameters. The principal results can be summarised as follows: the prevalent proportion of the activity of the radionuclide dispersed by an explosion (born by the blast wave and by air convection) is transferred to the detection system/collecting pads essentially within the first minute. Enhanced aerosol mass concentrations were also detected within the same period. The RaS carried by the blast wave passed through the polygon (50 m) within <1 s. An expected crucial impact of meteorological conditions at the moment of the explosion and shortly after was proved by the tests.

Brown Trout Spawning Migration in Fragmented Central European Headwaters: Effect of Isolation by Artificial Obstacles and the Moon Phase

AbstractThe spawning migrations of 123 brown troutSalmo truttawere studied in six highland streams in the Elbe River catchment area, Czech Republic, in central Europe. Trout were observed by using radiotelemetry from August to November in headwater stretches isolated by artificial obstacles without fish ladders. The length of isolated headwater stretches ranged between 5.7 and 16.1 km. Migration distance per day and total migration length over the study period (total migration) were analyzed. In total, 1,957 individual fish positions were recorded. In general, the brown trout spawning migration reflected the seasonality with respect to temperature. Migration distance per day was low in August, reached a maximum in October, and then decreased in November. In isolated headwaters, trout adapted their migrations to the length of available free migration stretches, as both migration descriptors (migration distance per day and total migration) increased according to this variable. Moon phase appeared to be the key factor that influenced the timing of brown trout migration activity on a daily basis. High migration distance per day occurred during the eclipse of the moon, whereas the lowest migration distance per day occurred during the full moon. Furthermore, migration distance per day decreased with increasing river slope. The other variables tested (sex and physicochemical parameters, such as flow, pH, conductivity, and dissolved oxygen) did not affect brown trout migration activity. The results indicated that despite the restrictions of upstream migrations by lateral obstacles without fish ladders, brown trout migration activity in artificially isolated headwaters with pristine morphology is preserved. Furthermore, the analyses revealed a significant impact of the moon phase on brown trout migration that has not been previously described for this species. Although the observed migration occurred over a short period of time, brown trout did not adopt sedentary behavior, as has been described in the river stretches upstream from natural obstacles, such as waterfalls.

Performance Evaluation of Homing Guidance Methods

A guided missile must be endowed with sufficient intelligence to acquire information for keeping it on course to the target, whether it was stationary or mobile. The guidance commands are generated to control the missile motion relative to target in accordance to the observed and estimated parameters for target motion. The necessity for guiding the missile motion is given by (1) the need to compensate for the non-standard conditions of the medium, technology, propulsion for the achievement of the desired accuracy, especially at greater ranges, (2) the need of reacting on the target maneuver during its flight, and (3) the need for conducting fire behind terrain undulations and artificial obstacles. According to the guidance and control philosophy utilized to control the missile motion and the location of the guidance computer, there are five types of guidance: Homing guidance, Autonomous guidance, Beam rider guidance, Command guidance and Combined guidance systems. The Homing Guidance may be active using onboard transceiver to provide the guidance signals, semi-active which combines an onboard receiver with external illuminator and passive which home on energy generated by the target. The performance of the guidance system is dependent upon the utilized guidance method which constraints the vehicles attitude during its flight. Therefore, this paper is devoted to evaluate the performance of homing guidance methods via the solution of the derived equations of c.g. motion in conjunction with ideal bond equations either numerically or analytically. The guidance performance is analyzed via flight path parameters obtained from the equations' solution. Note that the analytical solution can be very complex unless some simplifying assumptions are considered such as planer motion, constant speeds, etc. Then, the obtained equations are programmed as functions within the MATLAB environment (or any high level language) and the simulation is conducted using different engagements’ scenarios. The results justify the capabilities of each guidance method according to the engagement scenario and it will be of great value to young researchers and designers.

Animal Behavior

Many animals move great distances over the course of a year. This vast range of creatures and movements is highlighted in Ben Hoare's lovely book on animal migration. Hoare presents a fascinating diversity of land, water, and air migrants through text, photographs, maps, and diagrams.Animal Migration is organized into several sections. Initial pages address the basic definition of migration and reasons for migrations as animals search for food and mates. Questions of how animals navigate are presented (birds' use of star and sun compasses, sharks' use of magnetism, and whales' use of sound, to name a few), together with data and study techniques. The question of how animals time their migrations is addressed, as well as how animals prepare to survive their journeys (some whales double their body weight before embarking on their long fast of breeding and migration, and birds and butterflies reduce their reproductive organs to nonfunctional remnants in preparation for their flight). The origins of migration are discussed, with the very interesting suggestion that many migrants started with much shorter journeys that have grown as continents have moved and climate has changed. Several pages examine the sobering threats to migrations: the ““growing dangers”” of monoculture agriculture, artificial obstacles and broken landscapes, and, most significantly, the global danger of the effects of climate change. Most of the book is devoted to presenting the migrants themselves.Over fifty migrants are presented. Each two-page spread includes a small ““Migration Profile”” box (including the scientific name, a description of the migration route, the journey length, and suggested places and times to watch the migration), a map of the migration, and pictures of the animal, its movement, and its habitat. Well-written descriptions discuss in more detail related aspects of the migrations, including physiological adaptations and challenges. Many of the great well-known migrants are presented: Artic terns, wildebeests, whales, and albatrosses. The descriptions of the less-well-known migrations, and particularly the invertebrates, are part of what makes this book so fascinating: Christmas Island red crabs, monarch butterflies, and dragonflies, among others. Vivid presentations showcase the migrants and their gatherings; the book as a whole is a visual treat. The descriptions of the Australian giant cuttlefish gathering by the thousands to breed off the southern coast of Australia (5 feet in length and up to 30 pounds, flashing ““iridescent reddish-purple, yellow and greenish-blue””) made me want to drop everything and buy a ticket to Spencer Gulf for next September.Writing style, layout, photographs, and other visual presentations are excellent throughout. The only criticism of this book is probably a minor error of editing, although an alarming one, during the discussion of animals using a sun compass as a navigation tool, which confidently states that ““the sun is an ideal visual reference: every day it rises in the west and sets in the east?.”” No other errors were noted, and readers should not be deterred. A strong point particularly recommending this book is its emphasis not only on individual migrants, but on the place of each organism as a part of an ecological system. Overall, this is an excellent and beautiful book that would be a fine addition to any school or personal library, to be enjoyed by any student of science, zoology, or ecology.

Experimental study of the near-field impact of an oyster table on the flow

Oyster farming structures are artificial obstacles which disturb tidal flow and wave propagation. These effects can induce modifications of erosion and sedimentation patterns, turbidity changes, local silting up and can be threatening for the shellfish farming itself. The understanding of the impact of these structures in terms of hydrodynamics and sediment dynamics in the far-field, i.e. at the scale of a bay, is a very challenging task. In order to investigate the far-field impact, it is very important to understand in the first place all the changes which occur at a smaller scale, i.e. at the scale of a single table for a farm consisting of oyster tables made of metallic wire structures on which porous bags of oysters are laid. This work is carried out through the idealized representation of the in-situ flow in a free surface flume tank. The flow characteristics around the overall structure are determined from velocity measurements obtained by laser velocimetry. The results highlight an asymmetric development of the boundary layers which suggest the existence of preferential areas for silting up and suspended matter fragmentation under the table.

Ideals and Realities in Japanese Law Schools: Artificial Obstacles to the Development of Legal Education

This paper attempts to describe some problems of the new Japanese law school system. As a result of the conflict between the ideals and realities of law schools, many institutions are now facing crises in their existence. This conflict originates in the various tactics being employed to protect vested interests, for instance, in sustaining the existing Faculties of Law.

Great Britain and Her Efforts for the Establishment and Maintenance of the European Commission of the Danube (1855-1858)

The paper analyses the position of the British diplomats regarding the question of establishing a regime of free navigation on the maritime sector of the Danube. As the economic interests of English or French merchants, eager to conquer the grain commerce of the Romanian Principalities, were threatened at the Lower Danube by natural or artificial obstacles tolerated by the Russian authorities, the Sulina controversy was among the great international litigations that European diplomats wished to solve in the context of the Crimean War. During the Conference of Vienna (1855) and at the Congress of Paris (1856), debates around the international regime of the Danube were very complicated. The British representatives, acting in common with their French colleagues, fought for the establishment of a European Commission of the Danube, an international committee whose mission was to improve the conditions of navigation at the mouths of the river. The Eastern Empires, Russia and Austria, were opposing this initiative of the Maritime Powers, which endangered their own economic supremacy in the region. Thus, the initial success of establishing the European Commission had to followed by intensive efforts in order to make this body as solid and efficient as possible.

The Effects of Obstacles on the Dynamics of Ventricular Fibrillation

Background and Objectives:The effects of artificial obstacles on the dynamics of ventricular fibrillation have been extensively investigated with an electrical mapping system. This study was performed to assess the influence of transmural obstacles on the dynamics of wavefronts, and determine whether these can convert ventricular fibrillation to ventricular tachycardia by stabilizing the wavefronts in the fibrillating right ventricular tissues of pigs, using an optical mapping system. Materials and Methods:The right ventricles of pigs (n=15) were excised and placed in a tissue perfusion system, with the epicardium facing up. Holes, with increasing sizes, from 2 to 8 mm in diameter, were created using a skin biopsy punch. Another 8 mm sized hole was then made adjacent to the first, and the changes in the wavefront dynamics and cycle length of the optical action potential waves investigated. Results:In 14 of the 20 obstacles, in ten tissues, transient attachment of electrical activities along the rim of obstacles and transient rotation of the wavefronts were observed. During baseline ventricular fibrillation, the fibrillation cycle length was 118.5±24.7 msec, which was increased to 135.4± 30.2 msec after creation of the first hole, and to 159.4±47.7 msec after the second (p=0.01). There was a positive correlation between the obstacle size and cycle length (r=0.43, p=0.007). In three tissues, conversion to ventricular tachycardia from ventricular fibrillation was observed after creation of the two holes. Conclusion:Obstacles of an appropriate size had anti-fibrillatory effects in tissues with ventricular fibrillation, which was partly explained by the temporary attachment of wavefronts to the obstacles. (Korean Circulation J 2005;35:183-191)

Relationship between the Aerodynamic Roughness Length and the Roughness Density in Cases of Low Roughness Density

This paper presents measurements of roughness length performed in a wind tunnel for low roughness density. The experiments were performed with both compact and porous obstacles (clusters), in order to simulate the behavior of sparsely vegetated surfaces. The experimental results have been used to investigate the relationship between the ratio z0/h and the roughness density, and the influence of an obstacle's porosity on this relationship. The experiments performed for four configurations of compact obstacles provide measurements of roughness length z0 for roughness densities λ between 10−3 and 10−2 which are in good agreement with the only data set available until now for this range of low roughness densities. The results obtained with artificial porous obstacles suggests that the aerodynamic behavior of such roughness elements can be represented by the relationship established for compact obstacles, provided a porosity index has been used to determine the efficient roughness density (the fraction of the silhouette area actually sheltered by solid elements) rather than counting the porous object as solid. However, the experiments have been performed with relatively low porosity indices (maximum = 25%) for which the porosity has a negligible influence. In this range of porosity index, representing the aerodynamic behavior of porous obstacles using the relationship established for compact obstacles, should not lead to a significant error. However, the influence of the porosity may be important for porosity indices larger than 30%.

富士北麓地域における潜在風景と現況の対比による風景評価手法の開発

Keeping visibility toword broad landscape is one of the important function agricultural landuse. In purpose to clarify this function. we attached importance to the relationship between the actual physical from of local community and the landform as potential resource. In htis study we tried to compare them at 8 viewpoints in Fuji-Hokuroku (the northern foot of Mt. Fuji) area. To visualize the potential view from the ground level without artificial visual obstacles can provide, we simulated 3-D model using orthophotograph and DEM. Through the comparison between the actual photographs and this potential views at the railroad stations, we pointed out that the neighboring existence of paddy fields effectively preserves the visibility of Mt. Fuji.

Signal fading in land-mobile satellite communication systems: Statistical characteristics of data measured in Japan using ETS-VI

The space–earth links in land-mobile satellite communications are frequently cut off as a result of the shadowing and blockage, due to roadside trees, buildings, utility poles, and other artificial obstacles. Knowledge about the fade statistics is therefore important in designing cost-effective land-mobile satellite communication systems. Using a 15.5 dBi-gain satellite-tracking antenna, an S-band (2.1 GHz) unmodulated continuous-wave signal transmitted from the elliptically orbiting ETS-VI satellite was measured, while the vehicle the antenna was mounted on was driven around a city in Okinawa. The investigation reports on fade statistics and fade and nonfade-duration (interfade-duration) statistics for elevation angles ranging from 57.9° to 66.5° and for several thresholds of fade state (fade margins from 3 to 15 dB).