120 research outputs found
Investigation into the problem of characterization of the HF ionospheric fluctuating channel of propagation: construction of a physically based HF channel simulator
A wideband HF simulator has been constructed that is based on a detailed physical model. It can generate an output giving a time realization of the HF wideband channel for any HF carrier frequency and bandwidth and for any given transmitter receiver path, time of day, month and year and for any solar activity/geomagnetic conditions. To accomplish this, a comprehensive solution has been obtained to the problem of HF wave propagation for the most general case of a 3D inhomogeneous ionosphere with time-varying electron density fluctuations. The solution is based on the complex phase method (Rytov s method), which has been extended to the case of an inhomogeneous
medium and a point source of the field. Results of simulation obtained according to the technique developed have been presented, calculated for a single-hop path 1000 km long oriented to the south from St. Petersburg and including a horizontal electron density gradient present in the IRI model used as the basis of the ionosphere model. The fluctuations of the ionospheric electron density were characterized by an inverse power law anisotropic spatial spectrum. For this model, the random walk of the phasor at the receiver is determined and shown both for paths reflected in the E- and Fregions,
being significantly larger for the latter. The oblique sounding ionogram is constructed and reveals three propagation modes: the E-mode and low and high angle F-mode paths. The time-varying field due to each of these paths is then summed at the receiving location enabling the calculation
of the scattering function and also the time realization of the received signal shown as a function of both fast and slow time. This is performed both with and without the presence of the geomagnetic
field; in the former case the splitting of the F2-mode into both e- and o-modes is seen. It is also shown how the scattering function can be obtained from the time realization of the channel in a way
akin to experimental determination of the scattering function from channel measurements. Results from the simulations show the very significant effect of irregularities of even modest magnitude and
the comparative effects due to background ionosphere dispersion and the fluctuating irregularities as well as geomagnetic mode splitting. Since the simulator is based on a physical model, it should be possible by comparison of experimental results and simulation to identify the correspondence between physical parameters (e.g., the variance and anisotropy of the electron density fluctuations, orientation of the propagation path to the magnetic meridian, bulk ionosphere motions) with observed
channel parameters (e.g., Doppler spread and shift, time delay spread)
Scintillations effects on satellite to Earth links for telecommunication and navigation purposes
Radio wave scintillations are rapid fluctuations in both amplitude and phase of signals propagating through the atmosphere. GPS signals can be affected by these disturbances which can lead to a complete loss of lock when the electron density strongly fluctuates around the background ionization level at small spatial scales. This paper will present recent improvements to the theoretical Global Ionospheric Scintillation Model (GISM), particularly tailored for satellite based navigation systems such GPS coupled with Satellite Based Augmentation System (SBAS). This model has been improved in order to take into account GPS constellation, signals, and receiver response to ionospheric
scintillation environments. A new modelling technique, able to describe the scintillation derived modifications
of transionospheric propagating fields is shown. Results from GPS derived experimental
measurements performed at high and low magnetic latitudes will show preliminary assessments of the scintillation impact on real receivers and system operations. Nevertheless, comparisons between
theoretical scintillation models, such as WBMOD and GISM, with GPS derived experimental data will be shown
The efficiency of using the substrate technological module in the technology of growing potato mini-tubers
Known technologies and methods for obtaining virus-free potato mini-tubers of a required size fraction do not fully provide the highest multiplication factor, which occurs due to the insufficient productivity of an individual potato plant. On the basis of long-term experimental data (2012…2022), an assessment of the effectiveness of methods for growing potato mini-tubers in open and protected ground conditions is given. According to the number of tubers harvested from one plant, all growing methods can be divided into two large groups: traditional (3-12 potatoes per plant) and modified (more than 40 potatoes per plant). A highly efficient method has been developed for obtaining mini-tubers of potatoes harvested as they grow on soil substrates with an average annual productivity of at least 50 mini-tubers from one micro-tuber and 40 mini-tubers from one virus-free plant (with traditional substrate methods – from 3 to 10 mini-tubers). Based on this method, there has been created a substrate technological module of a new generation harvesting tubers as they grow which makes it possible to obtain an average of 40 to 55 mini-tubers from one virus-free plant over the years, that is almost 10 times more in comparison with traditional methods of growing with a single harvest at the end of vegetation. Harvesting mini-tubers as they grow up to a required size creates the possibility of obtaining tubers of one size fraction (10-25 g), which allows later, when laying the nursery of the first field reproduction, to apply mechanized planting in the field and obtain uniform seedlings
Scintillations effects on satellite to Earth links for telecommunication and navigation purposes
Radio wave scintillations are rapid fluctuations in both amplitude and phase of signals propagating through the atmosphere. GPS signals can be affected by these disturbances which can lead to a complete loss of lock when the electron density strongly fluctuates around the background ionization level at small spatial scales. This paper will present recent improvements to the theoretical Global Ionospheric Scintillation Model (GISM), particularly tailored for satellite based navigation systems such GPS coupled with Satellite Based Augmentation System (SBAS). This model has been improved in order to take into account GPS constellation, signals, and receiver response to ionospheric scintillation environments. A new modelling technique, able to describe the scintillation derived modifications of transionospheric propagating fields is shown. Results from GPS derived experimental measurements performed at high and low magnetic latitudes will show preliminary assessments of the scintillation impact on real receivers and system operations. Nevertheless, comparisons between theoretical scintillation models, such as WBMOD and GISM, with GPS derived experimental data will be shown
Обоснование конструктивных требований к автоматизированному посадочному агрегату мини-клубней картофеля
The authors showed that the transition to the technology of virus-free minitubers mass production changed the machines requirements for planting original seed potatoes.(Research purpose) To develop a technological scheme and substantiate the design parameters of the planting apparatus of an automatic planter of potato minitubers.(Materials and methods) The development was based on an elevator-type planting apparatus. The authors decided to create a spoon design with the ability to grip and move into the guide casing one minituber in each spoon, eliminating the minitubers jumping from one spoon to another or pinching them when moving along the guiding casing to the furrow bottom. The diameters of the lower guide and upper drive rollers were theoretically substantiated in order to exclude the influence of the planting tubers sizes difference on the uniformity of their submitting into the furrow.(Results and discussion) The authors determined the minimum permissible elevator belt speed, which depended on the distance between the spoons on the elevator belt and the planting unit speed. The size of the upper driving reel diameter was justified from the condition that the spoon unfolded 180 degrees in at least 1.5 seconds, which ensured a tuber smooth transition to the back side of the spoon.(Conclusions) The authors developed a technological scheme of an automatic planting elevator type device for planting potato minitubers with a working speed of 6-9 kilometers per hour. It was found that the upper driving reel diameter was not less than 44 centimeters, and the lower guide roller diameter was not more than 12 centimeters. They showed that the double-sided design of scooping spoons with the possibility of installing replaceable bowls in them would ensure a high-quality planting of not only minitubers, but also subsequent reproductions of seed and ware potatoes with a tuber mass of 5-80 grams.Показали, что переход на технологии массового получения безвирусных мини-клубней меняет требования к машинам для посадки оригинального семенного картофеля.(Цель исследования) Разработать технологическую схему и обосновать конструктивные параметры высаживающего аппарата автоматической сажалки мини-клубней картофеля.(Материалы и методы) За основу разработки взяли высаживающий аппарат элеваторного типа. Решили создать конструкцию ложечки с возможностью захвата и перемещения в направляющий кожух по одному мини-клубню в каждой ложечке, исключив перескакивание мини-клубней с одной ложечки на другую или защемление их при перемещении по направляющему кожуху на дно борозды. Теоретически обосновали диаметры нижнего направляющего и верхнего ведущего роликов, чтобы исключить влияние разницы в размерах посадочных клубней на равномерность подачи их в борозду.(Результаты и обсуждение) Определили минимально допустимую скорость ленты элеватора, которая зависит от расстояния между ложечками на ленте элеватора и скорости посадочного агрегата. Размер диаметра верхнего ведущего барабана обосновали из условия разворачивания ложечки на 180 градусов не менее чем за 1,5 секунды, что обеспечивает плавный переход клубня на обратную сторону ложечки.Выводы. Разработали технологическую схему автоматического высаживающего аппарата элеваторного типа для сажалки мини-клубней картофеля с рабочей скоростью 6-9 километров в час. Выявили, что диаметр верхнего ведущего барабана не меньше 44 сантиметров, нижнего направляющего ролика – не более 12 сантиметров. Показали, что двусторонняя конструкция вычерпывающих ложечек с возможностью установки в них сменных чаш обеспечит качественную посадку не только мини-клубней, но и последующих репродукций семенного, а также продовольственного картофеля при массе клубней 5-80 граммов
Historical and Cultural Project as a Tool of National-Ethnic Identification of Youth
В работе обосновывается необходимость реализации историко-культурного проекта «Бал Героев Отечества» как инструмента формирования образа героя у современной молодежи на основе традиционных этно-культурных представлений. Отмечается проблематика национально-этнической идентичности в условиях глобализации.The paper substantiates the need to implement the historical and cultural project “Ball of Heroes of the Fatherland” as a tool for shaping the image of a hero among modern youth based on traditional ethno-cultural ideas. The problems of nationalethnic identity in the context of globalization are noted
Ionospheric scintillation monitoring and modelling
This paper presents a review of the ionospheric scintillation monitoring and modelling by the European groups involved in COST 296. Several of these groups have organized scintillation measurement campaigns at low and high latitudes. Some characteristic results obtained from the measured data are presented. The paper also addresses the modeling activities: four models, based on phase screen techniques, with different options and application
domains are detailed. Finally some new trends for research topics are given. This includes the wavelet analysis, the high latitudes analysis, the construction of scintillation maps and the mitigation techniques
Механизация в технологиях семеноводства корнеплодов
Abstract. The sugar beet seed production is currently employing a non-planting-and-transplant technology with the use of steklings. Planting units of the machines available on the market feature a number of drawbacks: low productivity, possible injuring of root crops, and increased labor intensity of operators. (Research purpose) To develop a universal design and parameters of an increased-productivity unit for planting steklings of sugar beet and other root crops. (Materials and methods) The design scheme and type of a planting unit have been chosen according to the requirements of applicability and versatility. Its preferred design parameters have been calculated as well. A prototype machine with a universal planting unit in the form of a cellular disk has been developed and manufactured in test production. (Results and discussion) The conducted field experiments proved the versatility of a planting machine with a disc-type unit used for planting root crops, including dimensional characteristics corresponding to those of steklings. The authors have found that when replacing a disk with a different number of cells of different sizes, the machine is suitable for planting a number of similar crops. A removable disk with 12-16 cells has been installed, with its angular speed decreased to 0.393-1.180 radian per second, which is lower as compared to the existing machines. Satisfactory agrotechnical tolerances have been provided for carrot planting in the soil at a depth of 12 cm, a step of 30 cm, and a deviation from the vertical of 110. The intensity of root crop laying in the cells of a seeding disk has been increased to 1-3 pcs. per second. (Conclusions) It has been found that the machine and the planting unit can increase the working speed up to 1.0 meter per second and reduce the labor intensity of operators to the level of safety requirements. The use of universal machines in the breeding and seed production of root crops will reduce the range of the applied machines and operating costs of farm enterprises.Реферат. В семеноводстве сахарной свеклы набирает популярность эффективная безвысадочно-пересадочная технология с использованием штеклингов. Высаживающие аппараты, предлагаемые на рынке машин, имеют ряд недостатков: невысокую производительность, возможность травмирования корнеплодов, повышенную напряженность труда операторов. (Цель исследования) Разработать универсальную конструкцию и параметры аппарата повышенной производительности для высадки штеклингов сахарной свеклы и корнеплодов других культур. (Материалы и методы) По условиям применимости и универсальности выбрали конструктивную схему и тип высаживающего аппарата. Рассчитали его предпочтительные конструктивные параметры. Разработали и изготовили в опытном производстве макетный образец машины с универсальным высаживающим аппаратом в виде ячеистого диска. (Результаты и обсуждение) В полевых экспериментах подтвердили универсальность посадочной машины с высаживающим аппаратом дискового типа на высадке корнеплодов, в том числе с размерными характеристиками, соответствующими штеклингам. Выявили, что при замене диска с разным количеством ячеек различного размера машина пригодна для высадки целого ряда аналогичных культур. Установили сменный диск с 12-16 ячейками, снизив его угловую скорость до 0,393-1,180 радиан в секунду, что ниже по сравнению с параметрами высаживающего аппарата существующих машин. Обеспечили удовлетворительные агротехнические допуски по размещению корнеплодов моркови в почве на глубину 12 см при шаге посадки 30 см и отклонении от вертикали на 11 градусов. Повысили интенсивность укладки корнеплодов в ячейки высевающего диска до 1-3 штук в секунду. (Выводы) Установили, что машина и высаживающий аппарат позволят повысить рабочую скорость до 1 м в секунду и снизить напряженность труда операторов до уровня требований техники безопасности. Применение универсальных машин в селекции и семеноводстве корнеплодных культур снизит номенклатуру машин и эксплуатационные затраты хозяйств
Near-Earth space plasma modelling and forecasting
In the frame of the European COST 296 project (Mitigation of Ionospheric Effects on Radio Systems, MIERS)in the Working Package 1.3, new ionospheric models, prediction and forecasting methods and programs as well as ionospheric imaging techniques have been developed. They include (i) topside ionosphere and meso-scale irregularity models, (ii) improved forecasting methods for real time forecasting and for prediction of foF2,
M(3000)F2, MUF and TECs, including the use of new techniques such as Neurofuzzy, Nearest Neighbour, Cascade Modelling and Genetic Programming and (iii) improved dynamic high latitude ionosphere models through tomographic imaging and model validation. The success of the prediction algorithms and their improvement over
existing methods has been demonstrated by comparing predictions with later real data. The collaboration between different European partners (including interchange of data) has played a significant part in the development and validation of these new prediction and forecasting methods, programs and algorithms which can be applied to a variety of practical applications leading to improved mitigation of ionosphereic and space weather effects.Published255-2713.9. Fisica della magnetosfera, ionosfera e meteorologia spazialeJCR Journalope
Механизация в технологиях семеноводства корнеплодов
Abstract. The sugar beet seed production is currently employing a non-planting-and-transplant technology with the use of steklings. Planting units of the machines available on the market feature a number of drawbacks: low productivity, possible injuring of root crops, and increased labor intensity of operators. (Research purpose) To develop a universal design and parameters of an increased-productivity unit for planting steklings of sugar beet and other root crops. (Materials and methods) The design scheme and type of a planting unit have been chosen according to the requirements of applicability and versatility. Its preferred design parameters have been calculated as well. A prototype machine with a universal planting unit in the form of a cellular disk has been developed and manufactured in test production. (Results and discussion) The conducted field experiments proved the versatility of a planting machine with a disc-type unit used for planting root crops, including dimensional characteristics corresponding to those of steklings. The authors have found that when replacing a disk with a different number of cells of different sizes, the machine is suitable for planting a number of similar crops. A removable disk with 12-16 cells has been installed, with its angular speed decreased to 0.393-1.180 radian per second, which is lower as compared to the existing machines. Satisfactory agrotechnical tolerances have been provided for carrot planting in the soil at a depth of 12 cm, a step of 30 cm, and a deviation from the vertical of 110. The intensity of root crop laying in the cells of a seeding disk has been increased to 1-3 pcs. per second. (Conclusions) It has been found that the machine and the planting unit can increase the working speed up to 1.0 meter per second and reduce the labor intensity of operators to the level of safety requirements. The use of universal machines in the breeding and seed production of root crops will reduce the range of the applied machines and operating costs of farm enterprises.Реферат. В семеноводстве сахарной свеклы набирает популярность эффективная безвысадочно-пересадочная технология с использованием штеклингов. Высаживающие аппараты, предлагаемые на рынке машин, имеют ряд недостатков: невысокую производительность, возможность травмирования корнеплодов, повышенную напряженность труда операторов. (Цель исследования) Разработать универсальную конструкцию и параметры аппарата повышенной производительности для высадки штеклингов сахарной свеклы и корнеплодов других культур. (Материалы и методы) По условиям применимости и универсальности выбрали конструктивную схему и тип высаживающего аппарата. Рассчитали его предпочтительные конструктивные параметры. Разработали и изготовили в опытном производстве макетный образец машины с универсальным высаживающим аппаратом в виде ячеистого диска. (Результаты и обсуждение) В полевых экспериментах подтвердили универсальность посадочной машины с высаживающим аппаратом дискового типа на высадке корнеплодов, в том числе с размерными характеристиками, соответствующими штеклингам. Выявили, что при замене диска с разным количеством ячеек различного размера машина пригодна для высадки целого ряда аналогичных культур. Установили сменный диск с 12-16 ячейками, снизив его угловую скорость до 0,393-1,180 радиан в секунду, что ниже по сравнению с параметрами высаживающего аппарата существующих машин. Обеспечили удовлетворительные агротехнические допуски по размещению корнеплодов моркови в почве на глубину 12 см при шаге посадки 30 см и отклонении от вертикали на 11 градусов. Повысили интенсивность укладки корнеплодов в ячейки высевающего диска до 1-3 штук в секунду. (Выводы) Установили, что машина и высаживающий аппарат позволят повысить рабочую скорость до 1 м в секунду и снизить напряженность труда операторов до уровня требований техники безопасности. Применение универсальных машин в селекции и семеноводстве корнеплодных культур снизит номенклатуру машин и эксплуатационные затраты хозяйств
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