Results Of Field Measurements Research Articles

Underwater Holographic Sensor for Plankton Studies In Situ including Accompanying Measurements.

The paper presents an underwater holographic sensor to study marine particles—a miniDHC digital holographic camera, which may be used as part of a hydrobiological probe for accompanying (background) measurements. The results of field measurements of plankton are given and interpreted, their verification is performed. Errors of measurements and classification of plankton particles are estimated. MiniDHC allows measurement of the following set of background data, which is confirmed by field tests: plankton concentration, average size and size dispersion of individuals, particle size distribution, including on major taxa, as well as water turbidity and suspension statistics. Version of constructing measuring systems based on modern carriers of operational oceanography for the purpose of ecological diagnostics of the world ocean using autochthonous plankton are discussed. The results of field measurements of plankton using miniDHC as part of a hydrobiological probe are presented and interpreted, and their verification is carried out. The results of comparing the data on the concentration of individual taxa obtained using miniDHC with the data obtained by the traditional method using plankton catching with a net showed a difference of no more than 23%. The article also contains recommendations for expanding the potential of miniDHC, its purpose indicators, and improving metrological characteristics.

Development of a high precision small aperture quadrupole magnet with copper plate coils

Using the conventional coil manufacturing method, the iron core of a small aperture quadrupole magnet needs to be divided into four or more segments to install the excitation coils, which brings assembly errors and generates high-order magnetic field harmonics. In this paper, the development of a high-precision small-aperture quadrupole magnet named HQ22 using copper plate coils is described. The magnet has a bore aperture of 22 mm, a gradient of 90 T/m, and an effective length of 0.36 m. Its coil is mainly composed of a number of U-shaped copper plates, electrical connection sheets, and insulating sheets, which are directly assembled and connected on the pole. Outside the coil, water box with cooling water channel inside is installed to provide indirect cooling to the coil. Using copper plate coil, one-piece or two-piece structure can be adopted for the iron core, so the assembly error is reduced and magnetic field quality can be improved. The research provides an attractive technical scheme for small aperture quadrupole magnets in future light sources. The detailed magnet design, magnetic field calculation and measurement results of HQ22 are presented, and the application prospect of copper plate coil is discussed.

Site Measurements and Calculations of Electrostatic and Electromagnetic Fields of a 220-KV Overhead Transmission Line.(Dept.E)

Field measurements, whenever possible, still constitute the most direct method of obtaining quantitative as well as qualitative results concerning the values of both electrostatic and electromagnetic fields, provided adequate arrangements are used. It is also the usual practice to compare the results obtained by measurements with those obtained by calculations, The paper presents the results of electrostatic and electromagnetic field measurements produced under a 220-kV overhead transmission line. Two different sites along the line are selected for field tests, Simp lified measuring technique is used and the measurements are p erformed at different heights ranging from 1 m to 3 m above ground surface, with transverse distances up to 25 m around the centre of the transmission line. Using image theory and the quasi-static app roximation, corresponding results are calculated and compared with the test results. The comparison shows that the results obtained by field tests are in good agreement with those obtained by calculations. This concludes the adequacy of the simp lified measuring technique used in this investigation.

STUDY ON AXIAL FORCE TRANSFER FROM CFT COLUMN TO PILE OF HIGH-RISE BUILDING BY FIELD MEASUREMENT AND FEM ANALYSIS

Axial force of CFT column and steel column embedded into cast-in-place concrete pile were measured in top-down construction method. In addition, measurement results were accurately simulated by FEM analysis. Axial force transfer mechanism from CFT column to pile is analyzed according to field measurement and FEM analysis results. At the pile head, axial force of concrete transferred from steel column is increasing and becomes stable due to slipping between steel column and concrete. Besides, it was found that shear strength of stud connectors at the pile head are 60% of design shear strength.

Scanning laser wave recorder with registration of “instantaneous” sea surface profiles

AbstractA direct optical method for measuring the “instantaneous” profile of the sea surface with an accuracy of 1 mm and a spatial resolution of 3 mm is described. Surface profile measurements can be carried out on spatial scales from units of millimeters to units of meters with an averaging time of 10−4 s. The method is based on the synchronization of the beginning of scanning a laser beam over the sea surface and the beginning of recording the radiation scattered on the surface onto the video camera matrix. The heights of all points of the profile are brought to a single point in time, which makes it possible to obtain “instantaneous” profiles of the sea surface with the frequency of video recording. The measurement technique and data processing algorithm are described. The errors of the method are substantiated. The results of field measurements of the parameters of sea waves are presented: amplitude spectra, distribution of slopes at various spatial averaging scales. The applied version of the wave recorder did not allow recording capillary oscillations, but with some modernization it will be possible. The method is completely remote, does not distort the properties of the surface, is not affected by wind, waves and sea currents, it allows you to measure the proportion of foam on the surface. The possibility of applying the proposed method at any time of the day and in a wide range of weather conditions has been experimentally proved.

Energy efficiency assessment of electric shovel operating in opencast mine

Electric shovels are used for loading in opencast mines. Energy efficiency assessment of electric shovel is important to minimise its electrical energy usage. Specific power consumption (SPC) has been used as performance indicator to assess energy efficiency of shovel. A modelling framework is developed for estimating SPC of electric shovel from operating time and power measured for each process. The model is illustrated with a case study of 42 cu. m. P & H shovel operating in a large opencast mine of India. The SPC of shovel is optimized for actual operating cycle time components (idle time and digging time). Results of field measurements show that digging operation consumes maximum power in comparison to other operations of electric shovel in a cycle. The model has been used to assess the energy saving potential of electric shovel by using the real time operational data. The minimum SPC of electric shovel is 0.12 kWh/cum for zero idle time and the energy saving potential is 13.45%. The optimization of SPC has also been done for different digging conditions. The model developed can help to set a target for energy consumption of electric shovel operating in a mine.

Mechanism of steel pipe reinforcement grouting based on tunnel field measurement results

Mechanism of steel pipe reinforcement grouting based on tunnel field measurement results

ЧИСЛЕННОЕ ИМИТАЦИОННОЕ МОДЕЛИРОВАНИЕ РАСПРОСТРАНЕНИЯ ТЕМПЕРАТУРЫ ПРИ САМОНАГРЕВАНИИ УГЛЯ В ВЫРАБОТАННОМ ПРОСТРАНСТВЕ

Researches of thermodynamic processes of oxidation, self-heating and self-ignition of coal are necessary for studying of dependence of terminal parameters on a set of the influencing factors. In practice of coal mining by the underground method cases of coal self-ignition in the mined-out spaces of production units (lavas) are frequent. In this case one of the tasks consists in determination of temperature in arbitrary point of the nubbly-porous medium of the mined-out space. Need of the solution of this difficult task is caused by the probability of emergency situations in places with the explosive concentration of methane. It is possible that for each seam and grade of coal it is necessary to develop, substantiate and accept an individual indicator for assessing the state of fire hazard. It is proposed to systematize and methodically process the results of field measurements and observations on the analyzed and investigated cases of endogenous fires in problem areas of mines in order to create basin databases for subse- quent operational decisions in emergency situations.

Empirical numerical model of tornadic flow fields and load effects

Tornadoes are the most devastating meteorological natural hazards. Many empirical and theoretical numerical models of tornado vortex have been proposed, because it is difficult to carry out direct measurements of tornado velocity components. However, most of existing numerical models fail to explain the physical structure of tornado vortices. The present paper proposes a new empirical numerical model for a tornado vortex, and its load effects on a low-rise and a tall building are calculated and compared with those for existing numerical models. The velocity components of the proposed model show clear variations with radius and height, showing good agreement with the results of field measurements, wind tunnel experiments and computational fluid dynamics. Normal stresses in the columns of a low-rise building obtained from the proposed model show intermediate values when compared with those obtained from existing numerical models. Local forces on a tall building show clear variation with height and the largest local forces show similar values to most existing numerical models. Local forces increase with increasing turbulence intensity and are found to depend mainly on reference velocity Uref and moving velocity Umov. However, they collapse to one curve for the same normalized velocity Uref / Umov. The effects of reference radius and reference height are found to be small. Resultant fluctuating force of generalized forces obtained from the modified Rankine model is considered to be larger than those obtained from the proposed model. Fluctuating force increases as the integral length scale increases for the modified Rankine model, while they remain almost constant regardless of the integral length scale for the proposed model.

A New Earth Reinforcement by “Panel and Nail” for Slope Protection in Cold Region

Newly developed earth reinforcement for slope protection was applied in cold region. The reinforcement by this method is making use of precast concrete panels with insulation and anchor nails. The precast concrete panel is economical, of high quality, durable for weathering, earthquake-resistant and of good appearance, which contribute shortening construction period and less life cycle cost. We can construct for nearly vertical slope by placing panels downward from top of slope at the same time of slope cutting, and for reinforcing of existing retaining wall by simply covering and nailing as well. Practical case of design and construction is explained, and measurement results of temperatures, forces at anchor head during cold season are shown to ensure the protection. Especially concrete panels are designed with insulation for low temperature, and the result of thermal analysis and field measurement shows the insulation works well to stop freezing front going into ground.

Formation Mechanism and the Height of the Water-Conducting Fractured Zone Induced by Middle Deep Coal Seam Mining in a Sandy Region: A Case Study from the Xiaobaodang Coal Mine

The height of the water-conducting fractured zone (WCFZ) is a basic parameter related to water protection in coal mines and is also crucial for aquifer protection and mine safety. In order to accurately detect the height and shape and reveal the formation mechanism of the WCFZ, which is caused by middle-deep coal seam mining in a sandy region, the 112201 coalface at the 1# coal mine of Xiaobaodang was taken as a case study. Filed measurements including fluid leakage, borehole TV, and similar simulation were adopted to analyze the regularity of the WCFZ in this area. The detection results of field measurements showed that the maximum height of the WCFZ was 177.07 m in a borehole near the open-off cut, and the ratio of the height of the water-conducting fractured zone divided by the mining thickness was 30.53. The WCFZ acquired an inward-convergent saddle shape, which was inclined to the goaf. The saddle bridge was located at the boundary of the goaf, and the saddle ridge was located at the center of the goaf. Also, through analyzing the results of similar simulations, we found that, in the process of mining, separation cracks and the beam structure were the main forms of overburden disturbance transmitting upward and ahead of mining, respectively. The main cause of the increase in height of the WCFZ was the connection of the separation cracks and vertical cracks caused by fractures of beam structures. The development of the WCFZ was divided into five stages: incubation stage, development stage, rapidly increasing stage, slowly increasing stage, and stable stage. Moreover, the duration of each stage was related to the lithology and mining technology. This research can provide significant theoretical insights for the prediction of the WCFZ, enabling the prevention of water hazards on mine roofs and assisting with water resources protection.

Noise Sources of Combined Heat and Power Plants and Methods for Noise Estimation in Adjacent Urban Areas

Combined heat and power plants (CHP) are permanently operating enterprises for the production of electrical and thermal energy. They are located, as a rule, in cities and in large settlements, create significant noise pollution for the buildings adjacent to them. Protection from the noise of the territories adjacent to the heat and power plants, especially residential buildings, is a topical scientific and practical problem. Based on the results of field measurements, the article identifies and shows the main external sources of noise that determine the noise impact of the heat and power plants on the environment of the metropolis. Such sources include large-sized ground and above-ground equipment: air intake of blower fans and chimneys, transformers, gas distribution unites, gas pipelines, cooling towers. Reliable basic data on their acoustic power and the required amount of noise reduction have a special role for the development of optimal protection from the point of view of acoustics and economics from the noise of such sources. They can only be determined by calculation for a number of equipment sources of combined heat and power plants. The article presents new, computational methods that allow you to determine the desired data and, accordingly, to qualitatively design the necessary acoustic building noise reduction tools based on the methods of shielding, sound insulation and sound absorption.

A Magnetic Field In-Situ Measurement Method of the Heating Film in Atomic Sensors

For the magnetically sensitive atomic sensors, heating the vapor cell without introducing magnetic field is required. In order to evaluate the heating film magnetic field suppression effect, independent magnetometer is usually employed. However, in this method the accuracy of magnetic field measurement result is greatly affected by the distance between the magnetometer and the tested heating film, as magnetic field is inversely proportional to the distance. In order to overcome this issue, an in-situ magnetic field measurement method is proposed. The measurement principle is based on the Larmor precession of the spin polarized noble gases. The magnetic field of the heating film assembled into the atomic sensor can be measured by the atomic sensor itself. The measurement results directly reflect the influence of the heating film on the atomic sensor. So, the distance error existed in the independent magnetometer-based method can be avoided in principle. Owing to the in-situ measurement method, the measurement results can be used to evaluate the magnetic field suppression effect more accurately. Finally, it can be used for further improve the heating film performance.

Investigations on the Performance of Various Horizontal Ground Electrodes

Experimental work on grounding systems has shown that the characteristics of grounding systems under high impulse conditions are different than those obtained at steady-state conditions. Investigations on the grounding systems under high impulse conditions make it evident that ionization process could occur in soil, due to field enhancement in air voids in the soil. This process can lead to an ionization zone that reduces the impulse resistance of grounding systems (due to an enlargement of a virtually increased cross-sectional area) from its steady state. There have been many studies pointing towards the effect of various soils and the ground electrode’s arrangement on the reduction of impulse resistance from its steady state, and its decrease with increasing currents. It was, however, noted that very few studies on the effect of the configurations of horizontal ground electrodes have been performed by field measurements before. This work presents the experimental and simulated work of various configurations of ground electrodes, with spikes which are thought to enhance the ionization process in soil. In this paper, field measurement was set up, and the results of field measurements were applied with finite element method (FEM) to obtain the electric field values. It was demonstrated that with the addition of spike on the electrodes, a high electric field was computed. The time to peak current, discharged time and impulse impedance were also analyzed for various horizontal ground electrodes.

Repeated triggered ruptures on a distributed secondary fault system: an example from the 2016 Kumamoto earthquake, southwest Japan

The Mw7.0 2016 Kumamoto earthquake occurred on the previously mapped Futagawa–Hinagu fault causing significant strong ground motions. A ~ 30-km-long dextral surface rupture appeared on the major fault zone and dextral slip was up to 2–3 m. However, the surface ruptures were also broadly and remotely distributed approximately 10 km away from the primary rupture zone. These numerous distributed secondary surface slips with vertical displacement of less than a few tens of centimeters were detected by the interferometric synthetic aperture radar (InSAR) technology in previous studies. Such displacements occurred not only on previously mapped faults but also on unknown traces. Here, we addressed the following fundamental issues: whether the broadly distributed faults were involved in the past major earthquakes in the neighborhood, and how the fault topography of such secondary faults develops, seismically or aseismically. To find clues for understanding these issues, we show the results of field measurements of surface slips and paleoseismic trenching on distributed secondary faults called the Miyaji faults inside the Aso caldera, 10 km away from the eastern end of the primary rupture zone. Field observations revealed small but well-defined dextral slip surface ruptures that were consistent with vertical and dextral offsets derived from InSAR. On the trench walls, the penultimate event with vertical displacements almost similar to the 2016 event was identified. The timing of the penultimate event was around 2 ka, which was consistent with that of the primary fault and archeological information of the caldera. Considering the paleo-slip event and fault models of the Miyaji faults, they were presumed not to be source faults, and slip on these faults have been triggered by large earthquakes along major adjacent active faults. The results provide important insights into the seismic hazard assessment of low-slip-rate active faults and fault topography development due to triggered displacement along secondary faults.

Electric Mode Excitation in the Atmosphere by Magnetospheric Impulses and ULF Waves

Variations of vertical atmospheric electric field Ez have been attributed mainly to meteorological processes. On the other hand, the theory of electromagnetic waves in the atmosphere, between the bottom ionosphere and earth’s surface, predicts two modes, magnetic H (TE) and electric E (TH) modes, where the E-mode has a vertical electric field component, Ez. Past attempts to find signatures of ULF (periods from fractions to tens of minutes) disturbances in Ez gave contradictory results. Recently, study of ULF disturbances of atmospheric electric field became feasible thanks to project GLOCAEM, which united stations with 1 sec measurements of potential gradient. These data enable us to address the long-standing problem of the coupling between atmospheric electricity and space weather disturbances at ULF time scales. Also, we have reexamined results of earlier balloon-born electric field and ground magnetic field measurements in Antarctica. Transmission of storm sudden commencement (SSC) impulses to lower latitudes was often interpreted as excitation of the electric TH0 mode, instantly propagating along the ionosphere–ground waveguide. According to this theoretical estimate, even a weak magnetic signature of the E-mode ∼1 nT must be accompanied by a burst of Ez well exceeding the atmospheric potential gradient. We have examined simultaneous records of magnetometers and electric field-mills during >50 SSC events in 2007–2019 in search for signatures of E-mode. However, the observed Ez disturbance never exceeded background fluctuations ∼10 V/m, much less than expected for the TH0 mode. We constructed a model of the electromagnetic ULF response to an oscillating magnetospheric field-aligned current incident onto the realistic ionosphere and atmosphere. The model is based on numerical solution of the full-wave equations in the atmospheric-ionospheric collisional plasma, using parameters that were reconstructed using the IRI model. We have calculated the vertical and horizontal distributions of magnetic and electric fields of both H- and E-modes excited by magnetospheric field-aligned currents. The model predicts that the excitation rate of the E-mode by magnetospheric disturbances is low, so only a weak Ez response with a magnitude of ∼several V/m will be produced by ∼100 nT geomagnetic disturbance. However, at balloon heights (∼30 km), electric field of the E-mode becomes dominating. Predicted amplitudes of horizontal electric field in the atmosphere induced by Pc5 pulsations and travelling convection vortices, about tens of mV/m, are in good agreement with balloon electric field and ground magnetometer observations.

Dynamic Line Rating—An Effective Method to Increase the Safety of Power Lines

Exceeding the electric field’s limit value is not allowed in the vicinity of high-voltage power lines because of both legal and safety aspects. The design parameters of the line must be chosen so that such cases do not occur. However, analysis of several operating power lines in Europe found that the electric field strength in many cases exceeds the legally prescribed limit for the general public. To illustrate this issue and its importance, field measurement and finite element simulation results of the low-frequency electric field are presented for an active 400 kV power line. The purpose of this paper is to offer a new, economical expert system based on dynamic line rating (DLR) that utilizes the potential of real-time power line monitoring methods. The article describes the expert system’s strengths and benefits from both technical and financial points of view, highlighting DLR’s potential for application. With our proposed expert system, it is possible to increase a power line’s safety and security by ensuring that the electric field does not exceed its limit value. In this way, the authors demonstrate that DLR has other potential applications in addition to its capacity-increasing effect in the high voltage grid.

МЕТОДИКА ОЦЕНКИ ДЕФОРМАЦИЙ ВОДОПОДПОРНЫХ ПЛОТИН

Monitoring of the condition of water-supporting hydraulic structures (dams) is carried out in ac-cordance with GOST R 22.1.11–2002, which determines the list of main load indicators including hy-drostatic pressure exerted on the dam. The article gives the list of the main indicators of the condition of water-supporting hydraulic structures and the development of hazardous processes in soil massifs, which provides for the assessment of vertical (precipitation) and horizontal movements of structures and their bases. Thus, monitoring is carried out in two areas of research: the first is geotechnical; the second is geodetic. As a rule, surveyors develop an observation system, and geotechnicians, taking into account these data, determine the state of the dam. The article provides a methodology for ge-otechnical dam condition that combines these two areas. Accounting for hydrostatic pressure is possi-ble due to geodetic control of the water surface level and calculation of water reserves and, according-ly, the pressure on the dam. These data, together with the results of field measurements, make it possi-ble to identify critical and permissible water levels, which allow us to regulate the observation order depending on the water level. The article also considers an important issue about the scheme of de-formation marks location on the dam. Regular distance location is not always appropriate. A more ef-fective way is to locate them in accordance with the stress-strain state. On the basis of pre-calculation there was carried out irregular location of the deformation marks on the dam as well as the design and accuracy assessment of deformation network. The afore-mentioned approach is implemented on a specific example of the Dukan Dam in Iraq.

Results of full-scale and laboratory studies of the spillway of HPP No. 2

In the article, based on the results of field measurements and calculations, recommendations are given for determining the roughness coefficient of the channel of the spillway. Based on the analysis of the literature and field research data, it was recommended to take the roughness coefficient of the channel of the spillway (canal) equal to n = 0.02 - for areas with steep slopes and without sediment deposits, and in areas with the worst condition of concrete surfaces and sediment deposits, take n = 0.0225. According to the results of field surveys of the canal, it was found that the hydraulic regime at the turning section No. 2 in the plan is characterized by an uneven distribution of depths in its cross-sections. This is due to the curvilinearity of the turning section of the channel, which has an unacceptably small radius of curvature in the plan causing centrifugal forces and rising levels along the concave wall, which led to an overflow of water over the top of the channel walls. As a result of the conducted experimental - laboratory studies of the turning section of the outflow tract (channel), recommendations are given for reducing the water incursion on the banks, the height of the walls.

Vector Overhauser magnetometer POS-4: experience and prospects of application

The results of practical use of a POS-4 vector magnetometer, developed by the Research Laboratory of Quantum Magnetometry, UrFU (Yekaterinburg) and based on POS Overhauser sensors, are presented. Continuous measurements by POS-4 have been carried out at the Paratunka observatory (IKIR FEB RAS, Kamchatka) since 2015, were done at the Saint Petersburg observatory (GC RAS / IZMIRAN SPb Branch, Leningrad Region) in 2017-2018 and have been performed at the Arti observatory (Institute of Geophysics, UB RAS, Sverdlovsk Region) since 2020. On the new high-latitude observatory White Sea (IAGA code WSE, GC RAS / MSU, Nikolai Pertsov White Sea Biological Station , Karelia), POS-4 is used as a main variometer for magnetic measurements. In April 2019, the magnetometer was successfully used for field measurements on ice during the TRANSARCTIC expedition in the Barents Sea (AARI, Roshydromet). At the beginning of 2021 IZMIRAN started testing two POS-4 magnetometers at the Moskow observatory. According to the results of field and observatory measurements it was possible to identify the advantages and disadvantages of the magnetometer and provide the information for its developers for further modernization in order to improve its efficiency and reliability. Many years of experience in POS-4 application determine the areas where its scientific and applied usage will provide important results, for example, for magnetic measurements in the Arctic regions or for monitoring of active zones around volcanoes.