Results Of Field Measurements Research Articles

DEVELOPMENT OF AN AFFORDABLE METHOD FOR IMPROVING THERMAL INSULATION PERFORMANCE OF MONGOLIAN TRADITIONAL MOBILE HOUSING

This paper presents an insulation retrofitting method developed for nomadic mobile housing called ger, which is used by urban residents in Ulaanbaatar, Mongolia, to promote the shift from coal stoves to electric heating devices to reduce air pollution. Field surveys of current gers were conducted to ensure that the design and materials chosen were affordable with high market availability. The developed system was installed in a typical urban ger in winter to obtain feedback from residents and local stakeholders. The results of field measurements of indoor thermal conditions of a ger with and without retrofitting are reported.

Computation of Time of Concentration Based on Two-Dimensional Hydraulic Simulation

Time of concentration (TC) is a parameter in runoff estimation, used to study and design different types of projects in watersheds. Any error in TC calculation leads to an inaccurate estimation of the design flow, which can lead to over-sizing or under-sizing of designed facilities that can have great economic and environmental consequences. Therefore, choosing the correct method to estimate TC is of great importance. Due to the diversity of estimation methods in the literature, the obtained TC values are different. This study aims to present a new method to calculate TC, based on its main concept, i.e., the time required for a water parcel to reach its outlet from the farthest hydrological point of a watershed. A two-dimensional hydraulic simulation was used to model the water parcel travel. A watershed was selected as a case study, and its time of concentration was determined by salt solution tracing. The field measurement results were used for calibration of the numerical simulation model. Meanwhile, 31 empirical relations in the literature were reviewed to determine the most accurate ones. Estimated TC values were compared with the measured ones, and the relative error percentage was used to evaluate the accuracy of the result. In the empirical TC methods, the maximum error was above 300%, and the minimum error was 6.7% for the field studied area. The relative errors of hydraulic simulation outputs were between 3 and 27%. The results showed that only three empirical methods, namely Simas and Hawkins, SCSlag, and Yen and Chow, had the least errors respectively equal to 6.7%, 8.660%, and 13.5%, which can be recommended for the studied area and those with similar hydrological characteristics. On the other hand, hydraulic simulation is also introduced as an efficient method to determine TC which can be used in any desired watershed.

A revised Scruton number on rain-wind-induced vibration of stay cables

Rain-wind-induced vibration (RWIV) is a typical large-amplitude vibration for stay cables. Due to the complex influencing factors and unclear mechanism, a Scruton number criterion Sc is usually adopted for RWIV-resistant design. However, this criterion has proved to be too conservative. The original Sc number characterized independently by mass and damping can not accurately reflect RWIVs' characteristics, and it is still difficult to compare test results with field measurement using the traditional Sc number. In this work, cable vibrations were studied through wind tunnel experiments and field measurements, and it is concluded that aerodynamic damping varies with mass also influences cables’ responses. The variation law of aerodynamic damping is analyzed by wind tunnel experiments, while the total damping of an actual cable of the Jintang Bridge has been identified by an empirical mode decomposition (EMD) method and the random decrement technique (RDT). A revised Sc* number with clear physical meaning considering aerodynamic damping is proposed. The aerodynamic damping for lighter models can be up 10 times that of prototypes, which makes the Sc* numbers the same order of magnitude. The results of different wind tunnel experiments and field measurements show that most large-amplitude vibrations occur at Sc* = 1–2.5. And, it is necessary to consider aerodynamic damping for more comparable work and more accurate prediction.

Study of the impact of recultivated granite stone quarry dumps on the environment and agricultural land in the Leningrad region

The environmental condition of the granite stone quarry dumps and the adjacent areas of Kuznechnoye village in the Leningrad Region of the Russian Federation was evaluated based on the results of field measurements of dust concentrations in the air (fraction size 1-10 microns) and analytical determination of chemical element contents in soil samples by spectral emission analysis and X-ray spectrometry methods. It has been established that dusting of unreclaimed dumps under conditions of humid climate, which is observed most of the year, and high pH values of soils leads to the formation of polyelement technogenic geochemical anomalies of Pb, Zn, Cu, Ba and Sr. The data obtained can be used in the selection of the most effective method of reclamation of dumps.

A step-by-step approach to creating and tuning PVT-models of reservoir hydrocarbon systems based on the state equation

The article is considering a new effective step-by-step approach to creating and tuning PVT-models of reservoir oil and reservoir gas condensate mixtures. The method is based on the reproducing of the results of field measurements and basic laboratory studies of representative samples in thermodynamic modeling using cubic three parameters equation of state. Tuning PVT-model is used for reliable modeling of PVT properties of reservoir fluids (reservoir oil and reservoir gas) in the design and monitoring of field development, calculation of multiphase flow in wells and field pipelines, as well as in basin modeling. Proposed approach makes possible to tune the PVT model with high accuracy of both reservoir oil and reservoir gas condensate system to experimental data using a step-by-step procedure, where at each step, by changing one of the parameters of the equation of state, one of the PVT properties of the hydrocarbon system is tuned. Algorithmization and automated application of this approach in specialized software products is possible. Proposed approach allows tune reservoir oil PVT-models on the main PVT-properties such as saturation pressure, FVF, STO density, gas-oil ratio of reservoir oil and dependencies of dynamic viscosity and compressibility on pressure at reservoir temperature as well as STO density. The tuned gas-condensate PVT-model precisely reproduces the key properties such as dew point pressure, initial condensate content in the reservoir gas, z-factor of the reservoir gas, gas-oil ratio, stable condensate density, drop down curve by the result of CVD-test. PVT-models created on the base of the proposed method, provide reliable information on the properties of a reservoir fluid in development of flow simulation both using a reservoir simulation compositional models and using pseudo models “black oil”. The method is illustrated by the example of creation of the adequate PVT-models of various regions of Russia reservoir oil and reservoir gas condensate mixtures.

Magnetic field measurement system in vertical status for superconducting undulator cooled in Dewar

Superconducting undulators (SCUs) for advanced light sources are being developed rapidly to emit light with higher brightness and flux. The SCU consists of two superconducting magnets with a small gap, each with alternating poles. The SCU is invisible when operating in a Dewar or cryostat, so measuring the magnetic field in the narrow magnetic gap is a challenge in the development of the SCU. This paper presents a measurement system in vertical status for scanning the magnetic field of the SCU along the z-axis. The SCU is immersed vertically in 4.2 K liquid helium in a Dewar and the scanning is powered by a servo motor at room temperature. The measurement system overcomes the temperature difference of 300 K to drive the Hall probes to scan the magnetic field in the narrow magnetic gap of the SCU. In order to make the scanning area of the Hall probes coincide with the trajectory of the electron beam, a lot of detailed work on mechanical aspects has been done, such as controlling the positional accuracy of the Hall probes as they move, high precision machining and limiting the direction of movement. Unlike the currently reported magnetic field scans in the vertical status which are only available for SCU mock-ups of few periods, this system supports magnetic field measurements for SCUs up to 1.5 m long. The measurement system was validated on a 20-period SCU prototype, and after modification, the magnetic field of a liquid helium-cooled 30.5-period SCU was scanned. When the excitation current of the SCU with a magnetic gap of 7 mm is 450 A, the system measured a field distribution with a peak magnetic field of 1 T. The measurement system completed a full stroke trial run of 1750 mm before the 1.5 m SCU was machined. The results of magnetic field measurement from scanning in vertical status can be used as a reference for local shimming and correction of the magnetic poles of the SCU. This work establishes the SCU's ability to operate in cryostat horizontally.

Results of Magnetic Field Measurements with the 6-m BTA Telescope. VIII. Observations in 2014

Results of Magnetic Field Measurements with the 6-m BTA Telescope. VIII. Observations in 2014

On electric field measurements based on intensity ratio of 1 − and 2 + systems of nitrogen in discharges with high specific deposited energy

Analysis of optical emission spectroscopy (OES) in application to the measurements of the electric field has been performed for the nanosecond capillary discharge in molecular nitrogen at moderate gas pressure at high specific energy deposition. Significant discrepancy between results of electric field measurements by OES technique and capacitive probe measurements is demonstrated. Decay rates of excited species as well as rotation structure of corresponding optical transitions are used to identify possible population/depopulation channels of the () and N2(C3Π u ) states. Kinetic calculations taking into account additional quenching of the () and N2(C3Π u ) states by electrons, additional population of () by electron impact from the ground state of the molecular ion and by a reaction of excited N2() with the ground state of describes adequately behavior of experimentally measured emission of both considered systems.

Numerical and Experimental Study of Polymers Microwaves Heating

Heating polymers by microwaves is not common. In order to quantify the ability of micro-wives to heat different type of polymers, a bench measuring the dielectrics characteristics of polymers is built, and a numerical modeling of the waves-polymers interaction is achieved. Finite elements method is introduced to solve the Maxwell equations [6-8] and the energy equation. A series of numerical simulations test are performed: convergence tests are realized and the heating power distribution in the sample is obtained. Using the power distribution, we studied a transient heating process of a polymer (CAPA) sample by microwave. In order to validate the numerical approach, we set-up an experimental bench to heat the sample by microwave and measure temperature distribution, using optical fiber and pyrometers. A vector analyzer (VNA). [6, 9-12] is used to check the quality of the microwave cavity The results of the numerical simulations of the wave propagation are presented and the amplitude of the electric field is compared to the experimental measurement: good agreement is observed. In terms of polymer heating, numerical results of temperature field and experimental measurements are also compared: an efficient heating is observed.

Method for Estimating the Tripartite Array Back-Azimuth Error Caused by the Far-Field Approximation

Abstract In recent decades, tripartite arrays (i.e., three-element array) have become an important tool for various seismoacoustic applications, mainly due to their superior back-azimuth estimation. However, the back azimuth is estimated assuming the far-field approximation. Lately, tripartite arrays have been used to monitor microseismicity and aftershocks at distances comparable with the size of the array in which the far-field assumption might not hold. In this work, we determined the validity of the far-field assumption by analyzing the plane-wave errors, that is, the errors of the back azimuth and slowness computations caused by the plane-wave assumption. Computational formulas for estimating the absolute errors, due to the plane-wave assumption, were developed. Several case studies demonstrated that the plane-wave errors are not theoretical issues only and taking them into account can improve the results of field measurements. Proposed practical methods to account for plane-wave errors can improve the performance of arrays aimed to measure low magnitude events such as in induced microseismicity monitoring or on-site inspection.

Voltage-sag source detection: Developing supervised methods and proposing a new unsupervised learning

Recognition and analysis of voltage sags (dips) allow network operators to predict and prevent problems in real-life applications. Clearing the voltage sag source by direction detection methods is the most effective way to solve and improve the voltage sags and their related problems. However, the existing analytical methods use single or two input features as phasor-based (PB) or instantaneous-based (IB) values. Hence, their limited maximum accuracy is given at 93% and 84% when using PB features for noiseless and high-level noise signals, respectively. To increase the detection accuracy, the main contributions of this research by proposing machine learning (ML) methods include: (a) Developing nine supervised methods including support vector machine (SVM)-based, tree-based, others, and an ensemble learning of said methods, and providing a comparative analysis (b) Employing a set of PB, IB, and both PB and IB input features as noiseless and noisy; (c) Finding the best developed supervised methods by highest possible accuracy under subsets said in (b); (d) Proposing a new unsupervised method fed by both PB and IB features using a sparse principal component analysis (SPCA) applied to a k-means clustering with an internal SPCA approach. The proposed unsupervised schema does not use the upstream/downstream labels in developed supervised methods. Extensive simulations of voltage sags due to fault and transformer energizing on a Brazilian regional network show that regardless of the sag sources, input feature subset, and noise levels, the random forest (RF) models yield the best performance so that noiseless-RF (99.84%) using both PB and IB features is the most effective one. The proposed unsupervised method outcomes an overall accuracy of 99.17%-noiseless and about 90% for high-level noises. This performance is higher than analytical methods, very close to SVM-based supervised methods, and uses no predefined labels. Moreover, the results of Slovenian field measurements confirm the effectiveness of the best-developed supervised methods and the proposed unsupervised learning.

SCCU—Compact Variable-Gap Undulator with hydraulic-assist driver and enhanced magnetic field

We developed, prototyped, built, and tested a compact variable-gap undulator with hydraulic-assist driver and innovative hybrid magnetic structure. The hydraulic system provides compensation of magnetic forces and ensures compactness of the design. Owing to innovative magnetic structure, this undulator demonstrated magnetic peak field ∼15% stronger compared to conventional hybrid-structure undulators.The undulator is 1.5 m long, 0.38 m high, 0.21 m wide and weighs ∼180 kg. Magnetic structure has 28.4 mm period and 6.5 mm minimal gap. The gap can be varied from 6.5 mm to 45 mm. At minimal (6.5 mm) gap, the undulator demonstrated 1.34 T peak magnetic field. Magnetic field measurements indicated satisfactory uniformity of the field and acceptable field integrals through the entire gap range. High reliability of undulator mechanics and the control system was confirmed by extensive, varied and prolonged testing.In this paper we discuss mechanical and magnetic design of the device, present results of magnetic field measurements and describe the control system (CS) algorithm and CS operation. At the end we summarize advantages of the new undulator and discuss possible applications of the developed techniques.

The use of deflection bowl parameters to evaluate the structural condition of the North Coast Corridor of Java Island

Monitoring the structural condition of the pavement is a very important process to be carried out periodically because it can estimate the damage that occurs as early as possible. However, this process is still constrained due to the limited non-destructive pavement response measuring instrument available and the lack of expertise in analyzing the structural condition of the road from the results of field measurements. Currently, the deflection bowl parameter method is one of the methods developed in research in South Africa to provide a more user-friendly method in determining the indication of the bearing capacity of the pavement layers. The use of this method in Indonesia is still limited, so this study aimed to evaluate the suitability of its use on roads in Indonesia. For this purpose, deflection data was collected from several arterial roads on the North Coast of Java Island. The study resulted that the deflection bowl parameter method generally can be applied to roads in Indonesia. However, the method has to be used with caution because of the complexity of the pavement structure layers on the North Coast Road of Java Island, especially for the layers that have undergone major repairs. In addition, the benchmarking process for the deflection bowl parameter criteria also only applied to roads with medium traffic load repetitions (up to 50 million ESAL), so upgrading the limit of the traffic load of the parameters was required so that the parameters could be used for roads with very high traffic load repetition as the one at the North Coast corridor.

Оценка технического состояния оснований, фундаментов и железобетонных колонн каркасного здания

The paper presents the results of assessing the technical condition of foundations, foundations and reinforced concrete columns, which are elements of building structures of a multi-storey frame public building. The results of the survey of foundation structures and the characteristics of the soil base are given. The physical and mechanical characteristics of soils were determined using samples taken from the pits during the survey. The results of visual examination and field measurements of foundations in control pits are given. The results of calculating the strength of concrete foundations and columns are given. The construction and correction of the calibration dependence of the indirect non-destructive testing method was carried out on the object using the method of separation with shearing. The results of verification calculations of foundations are considered. Defects and damages of foundations were revealed. The category of technical condition of bases and foundations is substantiated. Recommendations for the repair of foundations have been developed. The design and reinforcement of columns are considered. Identified defects and damage to the columns. the results of verification calculations of columns are given. The category of the technical condition of the columns is determined. Recommendations for the repair of columns have been developed. Defects and damages of reinforced concrete columns recorded in the list of defects and damages are investigated. The main conclusions are made based on the results of a survey of foundations and reinforced concrete columns of a multi-storey frame building.

Research on dynamic response and fatigue life of tunnel bottom structure under coupled action of train load and groundwater

In this paper, based on a heavy-duty railway tunnel, the vibration characteristics and fatigue life of tunnel basement structure under the coupled action of train load and groundwater were studied by field tests and numerical simulation. The results showed that the field measurement and numerical simulation results were in good agreement, and the vertical dynamic stresses of the grade-IV and -V surrounding rock were attenuated significantly along the tunnel base. The attenuation rate to the bottom of the inverted arch were 88.6% and 87.0%, respectively. Thus, the inverted arch and the filling layer were the main carriers of the train dynamic load. When water damage occurred in the basement, the vertical displacement and vertical acceleration of the basement structure decreased due to the pore water pressure, but the principal stress increased significantly. Under conditions where the surrounding rocks of grade-IV and -V have water compared with no water, the lifespan of the inverted arch decreases by 21.07% and 29.28%, respectively. The worse the quality of the surrounding rock was, the greater the dynamic response and the shorter the life of the basement structure became.

Analysis of the frequency deviation in off-grid power system of oil field

The paper represents the results of field measurements in the off-grid power system of oil field including diesel power plant, which supplies drilling rig system BU-4500/270 EK-BM. The data has been processed using the instantaneous power theory by Hirofumi Akagi. The active power load diagram of diesel power plant and power system frequency schedule have been obtained for hole drilling technological process of drilling rig. Abrupt load changes during drilling lead to large frequency deviations, which do not allow using gas piston generators in power system of oil field without revision of number and rated power of generators or using electrical energy storage system.

Study on Sunshine Stress Effect of Long-Span and Wide Concrete Box Girder

In order to further clarify the sunshine stress effect of long-span and wide concrete box girder, the study selected a concrete box girder with 4 × 42 m span and 33.5 m width, formed the temperature field load through a field test and numerical simulation, established a numerical analysis model by using the finite element program of ANSYS, and comprehensively analyzed the longitudinal temperature stress distribution of a long-span and wide concrete box girder under sunshine. The midspan section of the first span of the box girder is selected for field stress measure, and the field measure results and numerical analysis results are compared and analyzed. The research shows that the results of field measurement and numerical simulation are basically consistent. Sunshine temperature has a great influence on long-span and wide concrete box girder, which should be paid enough attention.

Wetting circumstances, expected moisture content, and drying performance of CLT end-grain edges based on field measurements and laboratory analysis

The moisture safety of cross-laminated timber (CLT) has gained attention as a result of feedback from construction sites and efforts have been made to protect CLT panel surfaces from wetting. However, the end-grain water absorption of CLT has often been overlooked. This study presents data from six CLT buildings where systematic moisture content (MC) measurements were made from when the CLT panels were installed until the commissioning of the buildings. Field measurement results were verified in a laboratory test where moisture uptake and moisture dry-out were monitored. On-site measurements showed that the wetting of CLT end-grain edges was common. Moisture absorption was detected in the end-grain edges in all the studied buildings and often MC > 25% persisted for many months until specific heating or drying was applied. Critical MC occurred after single rain events which suggests that a fast construction process is not always enough to avoid moisture ingress. Protection foils or membranes on the CLT panel faces did not help avoid end-grain wetting in the CLT joints. Protruding details such as floor panels or rubber bands under wall panels facilitated water intrusion. Areas with the CLT end grain exposed to ambient air experienced delamination post wetting. Laboratory test results confirmed very limited moisture dry-out in a typical CLT wall to floor joint but a potential to dry-out if the end-grain edges were exposed to dry and warm air. Specific methods to block water absorption into CLT end-grain edges should be used and joint detailing is crucial.

Rooftop rainwater harvesting and artificial roundwater recharge - a case study: Thanh Xuan district in south of Hanoi

Groundwater over-exploitation in the south of Hanoi has formed depression cones and accelerated land subsidence. Thanh Xuan district is one of the most suffered areas in the south of Hanoi. Artificial groundwater recharge (AGR) is an effective solution to mitigate those negative impacts. This study aims to evaluate the potential of rooftop rainwater harvesting (RRH) for AGR in the Thanh Xuan district. The prospect of RRH for the study area is estimated based on the average annual rainfall for the period 2008-2018 and the total rooftop area of selected buildings. The rooftop area is determined by analyzing satellite images and using the built-in tool in Google Earth. Field site investigation and measurements confirmed this estimation. Rainwater samples were taken for quality assessment. This assessment was conducted by measuring pH, EC, TDS, turbidity of rainwater in the field and analyzing NO3-, NO2-, PO43-, SO42- and Cl- contents in the laboratory. Moreover, to propose an effective AGR system, the maximum harvested rainwater and the recharge capacity of an injection well were estimated for the Golden Land building. The results show that 397 selected buildings can be used to collect rainwater. The total rooftop area of these 397 buildings is 262,645.8 m2, and that can contain 385,930.5 m3 of rainwater a year. The field measurement and analysis results indicate that rainwater quality meets the current standards appropriate for AGR. The AGR using rooftop rainwater will contribute to increasing groundwater level, reducing land subsidence, and mitigating urban flooding for Thanh Xuan and similar areas.

Coherent Structures at the Interface between Water Masses of Confluent Rivers

The paper presents the results of field measurements and numerical modeling of the influence of various factors on the formation of coherent structures in the confluence zone of the Sylva and Chusovaya rivers, which are dammed by the Kamskaya Hydroelectric Power Station (HPS). A characteristic feature of the measured parameters in the zone under study is that they experience both seasonal fluctuations and fluctuations of much higher frequency associated with intraday regulation of the HPS operation. These intraday fluctuations give rise to coherent structures with periodicity T~2–10 min, which manifest themselves in the fluctuations of the specific electrical conductivity of water. The flow velocity also experiences significant fluctuations with a sufficiently wide frequency spectrum, although the characteristic period of its fluctuations is less than the period of electrical conductivity fluctuations and is equal to ~1 min. In order to study the features of the formation of such structures, numerical simulation was carried out within the framework of the three-dimensional approach. Calculations were performed for a 300-meter-long stretch of the Chusovaya River, which is located downstream of the confluence of Chusovaya and Sylva rivers and is the site of the Chusovskoy water intake of Perm city. It was found that the intraday irregularity of HPS operation gives rise to the occurrence of vortex structures in this layer, leading to the temporal variation of concentration at a given point of space and the formation of the wave structure of the concentration field at different moments of time. Time period and spatial scale of such vortex structures depend on the ratio of velocities of water masses and difference in their mineralization and, accordingly, in densities. Moreover, the period of fluctuations is proportional to the ratio of flow velocities. These estimations are of fundamental importance for the implementation of stable selective intake of water with required consumer properties under conditions of intraday irregularity of hydroelectric power station operation.