Results Of Field Measurements Research Articles

First field measurements of optical turbulence near the ground with a newly developed fine-wire thermometer

First results of optical turbulence field measurements collected with a newly developed fine-wire temperature sensing system are presented and discussed. The centerpiece of the sensing system is an array of fine-wire platinum resistance thermometers. The active fine wire in each sensor element has a diameter of 0.64 μm and a length between 0.5 and 1 mm. The sampling rate is 44.1 kHz, and the noise level is 1 mK for a bandwidth of 10 kHz. Data were recorded while the car onto which the sensors were mounted was traveling at a speed of about 40 mph, or 18 m s . Estimates of the temperature structure function are compared against the classical Obukhov-Corrsin theory, which predicts power-law asymptotes with in the viscous-diffusive range and in the inertial-convective range. For the pair of separations cm and cm, we observed . The frequency spectrum follows the theoretically predicted power law in the inertial-convective subrange. The ‘Hill bump’ in the transition regime between the inertial-convective and viscous-diffusive subranges is visible.

Determination of solutions for chorus excitation mechanism characteristic equation by means of Van Allen probe data analysis

In this paper, we focus on studying the quantitative characteristics of the excitation mechanism of chorus emissions closely related to the problem of relativistic electron flux formation in the radiation belts. The study is based on the processing of information accumulated by the Van Allen Probe spacecraft through the analysis of high-resolution data. We have chosen two typical examples of chorus emissions with spectral forms predominantly in the upper-frequency band (above half the electron cyclotron frequency) in the region of the local minimum of the magnetic field outside the plasmapause in the middle magnetosphere. We have developed and implemented a calculation algorithm that enables us to represent the results of wave field measurements in a high-resolution data channel in the form of a rectangular event matrix, each row of which corresponds to a cycle of the wave process. In the event matrix, we select the rows corresponding to fragments of chorus emissions that best characterize the natural source of short electromagnetic pulses. This method made it possible to determine the complex eigenvalues of the characteristic equation of the chorus emissions source. The proposed method for processing experimental information makes it possible to determine the main characteristics of the linear mechanism of chorus excitation. The results obtained in this way from observational data are in good agreement with relevant theory of chorus emissions excitation by amplifying noise electromagnetic pulses in a duct with a depleted density of a cold plasma.

The Investigation of Indoor Air Temperature Effects for Different Types of Window Dimensions Using CFD Simulation

Windows plays an important role in heat transfer and natural ventilation in buildings. In the field of building design, the challenge is to provide a thermally comfortable indoor environment that requires the least energy consumption to maintain. One of the energy reduction alternatives that can be incorporated into modern building design is the installation of efficient windows. The windows should allow thermally acceptable indoor air quality and have a pleasant design while being energy efficient. Good thermal conditions in school buildings, especially learning spaces, promote the educational process. Unfulfilling comfort levels can reduce the lecturers’ and students' physical and intellectual performance. One of the variables that affect the thermal comfort condition is indoor air temperature. The purpose of this study is to investigate the effect of window size on indoor air temperature by using Computational Fluid Dynamics (CFD) simulation. The selected classroom at Universiti Teknologi MARA (UiTM) Permatang Pauh, Pulau Pinang will be used as a case study. The field measurement result can be used to validate the simulation result. The simulation result will be compared to standard regulations set by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) Standard 55-2017. Three different sizes of windows have been chosen in this study which are double, triple, and quadruple-glazed windows. The validation result shows the percentage difference in indoor air temperature between the experimental and simulation is 1.04 %. The result found double and triple-glazed windows show the value of temperature under the range set by ASHRAE Standard 55-2017. The selection of triple-glazed windows is more suitable because the brightness of the classroom meets the criteria for the absence of direct solar radiation. In conclusion, the size of the window shows the performance in terms of heat transfer and indoor air temperature of the classroom.

Identification of Alteration Zones Based on Resistivity and Induced Polarization Geoelectric Survey

Air Putih, Lebong Regency's geothermal field, is near gold mining. The relationship between the two can be illustrated in the type of rock alteration. The study aims to identify the rock alteration zone caused by the Air Putih, Lebong Regency geothermal system. It was described by the correlation of rocks' resistivity and chargebility values based on geoelectric measurement. Two tracks spread along the Air Putih tour, with a track length of 240 meters, were used to see variations in resistivity and chargeability values and the depth of geothermal potential due to deeper current penetration to determine the alteration zone in the study area. The results of field measurements are in the form of 2D models processed with Res2DinvX64 software. According to analysis, the subsurface rock lithology in the research area is relatively the same because the location of the two measurement lines is still close together; namely, there are wet valley rocks and alterated rock layers. Pores cause rock layers found in conductive areas in the rock filled with fluid or water at high temperatures. It is evidenced by the detection of manifestations on the surface in the form of warm soil, warm rocks, steamy soil, and small holes containing water grains. The higher the temperature and pressure, the lower the value of rock-specific resistance. At the Air Putih tourist area of Lebong Regency, it is found that it is a zone of prophylitic alteration containing several minerals of andesite lava, breccia, tuff, and soil.

ExoMars-2022 Mission ODS Instrument: Modeling and Ground Field Measurements

The paper presents the results of modeling and ground-based field measurements of the ODS (Optical Depth Sensor) instrument, designed to study aerosol in the Martian atmosphere through daily measurements of illumination on the planet’s surface. The device was part of the meteo suite located on the landing platform of the ExoMars-2022 mission. The article presents the structure of the instrument, its optical design and the spectral characteristics of two channels. The main elements of the model for calculating the radiation flux measured by the instrument are described depending on the structure of the atmosphere, the aerosol suspended in it, and the daily motion of the Sun. The calculations were carried out in the approximation of a pseudospherical atmosphere, taking into account the multiple scattering of radiation. Using the created model adapted for the Earth’s atmosphere, the ODS signal was simulated for two series of ground-based field measurements at different latitudes. The measured daily dependences in comparison with the simulation results make it possible to determine the optical depth with an accuracy of 0.1.

Assessment of Motor Vehicle Noise Levels on the Territory of New Residential Complexes in Voronezh City

Introduction: Adverse human health effects of motor vehicle noise, which levels are the highest in urban areas, are considered in many foreign and domestic studies. Objective: To establish the zone of acoustic discomfort related to motor vehicle noise on the territory of new residential complexes in the city of Voronezh. Materials and methods: Using the “Assistant” sound level meter (accuracy class 1), we conducted 72 noise measurements at 36 monitoring points within the 20.5 hectare area of two residential complexes at distances of 7.5, 50, 100, 200, 300, 350, and 430 meters from the four-lane highway, the main local source of traffic noise. The measurements were taken in May 2023 on working days (Monday to Friday) in the daytime and at night. Results: We have established that modern urban planning technologies and solutions used in the construction of new residential complexes are unable to eliminate the zone of acoustic discomfort. According to the results of field measurements, the equivalent noise level along the highway in the daytime exceeds permissible levels by 17.8–19.7 dBA and at night – by 22.6–25.7 dBA. The noise limit is also exceeded in the inner yard (on the playground, in the recreation area). The significant area of the study object is almost completely affected by traffic noise at the distances of up to 100 m and 200 m in the daytime and at night, respectively, which creates an unfavorable acoustic environment that has a negative impact on the local residents. Conclusions: To reduce the area of the acoustic discomfort zone, it is recommended to take measures to reduce traffic intensity in the study area by developing the road network and public transport system, prohibiting motorcycle and freight traffic on this street, especially at nighttime, improving landscaping of the adjoining territory, and installing transparent noise barriers that will prevent noise transfer between houses to the inner territory of the residential complex and the lower floors of the buildings.

Geoelectrical model of the Earth’s crust along the Shu-Sarysu geotraverse according to magnetotelluric soundings

Purpose. To study and assess the possibility of effective application of electrical prospecting by magnetotelluric sounding (MT-sounding) and to determine the range of geological problems to be solved in the geoelectric conditions of the Shu-Sarysu geotraverse. Methodology. The issues of methodology of modern technologies of field observations, peculiarities of processing and interpretation of MT-sounding data are considered, which showed that modern instrumental and methodical electrical survey technologies of MT-sounding allow obtaining results of field measurements of increased reliability, due to their accuracy, productivity, mobility, noise immunity, level of automation. To identify the main features of the geoelectric structure of the Earth’s crust and the upper mantle, the modern technique of interpreting MT data allows for 1, 2D inversion of the effective curves of apparent resistivity and impedance phase. Findings. Based on MT-sounding data, a geoelectric section of the Shu-Sarysu geotraverse was constructed, characterizing the position and morphology of five geoelectric boundaries in the crustal section in the 0–40 km depth interval. The identified five geoelectric horizons show good coincidence with the conventional seismic horizons and confidently correlate with the geological references established by GIS data. Originality. On the basis of MT-sounding studies, the geological interpretation of the structure of suprasalt and subsalt structural-formation complexes is presented; the geological efficiency of MT-sounding electrical prospecting in revealing the complex structures in the conditions of the Shu-Sarysu geotraverse is shown. On the basis of model constructions of the geoelectric section, new data on the deep geological structure of the Shu-Sarysu geotraverse were obtained: new data on the structure of Mesozoic terrigenous-sedimentary rock complexes and the Paleozoic part of the section with the allocation of the supposed faults; on the basis of MT-sounding results, recommendations for further detailed geological exploration work were given. Practical value. A comprehensive interpretation is recommended of the obtained MT-sounding data together with the results of geological and geophysical research on the regional profile in order to establish search criteria for the discovery of mineral deposits and the prospects of gas content in the area.

Effect of ventilation on thermal and humidity environment of the underground utility tunnel in the plum rain season in southern China: Field measurement and CFD simulation

The underground utility tunnel (UUT) is one of the typical urban underground structures, which usually requires mechanical ventilation systems for forced ventilation. In addition to the ventilation scheme for accident scenarios, the normal operating ventilation scheme deserves equal attention as it has a great impact on the air quality as well as the thermal and humidity environment inside the UUT. In this study, a UUT located in southern China is taken as the research object, and the effect of ventilation on its internal thermal and humidity distribution is explored with a combined use of field measurements and numerical simulations. The results of field measurements show that the average temperature inside the closed UUT is 20.5 ℃ and the average humidity ratio is 14.1 g/kgdry; both are lower than those of the external environment. In the plum rain season, if the tunnel is ventilated without any treatment of the external airflows, surface condensation tends to occur near the air inlet while the region with high relative humidity would be distributed on both sides far from the air inlet. The study also discusses the effect of different temperatures and humidity ratios of the inflow air on the humidity inside the UUT, and on this basis, the humidity control strategy for UUT in the plum rain season is proposed.

Using a magnetic flux leakage method to estimate railway track bolted joint gaps

The periodic estimation of the rail joint gap values allows evaluating the reliability of the continuous welded railway track and preventing its temperature deformations. The purpose of this study is to search for a simple and reliable way to evaluate the rail joint gap, which allows you to determine the desired values during high-speed inspection in automatic mode in a wide range of temperatures. A brief overview of existing techniques for evaluating rail joint gaps based on different physical principles is given. In the proposed technique, a magnetic flux leakage (MFL) method with the placement of electromagnets on the wheel axes of a car bogie is used. Such magnetization systems are applied recently on flaw-detector cars and provide a stable magnetic flux in the tested rails. Using a three-dimensional model of the rail segment with a bolt joint, we studied the characteristics of the magnetic flux leakage fields when changing the size of the rail gap in the entire practical range. The characteristics are selected that are most sensitive to a change in the gap and by which its value can be determined. With small values of the gaps the amplitude of the magnetic sensor signal is proposed as a main informative parameter, and with large gaps the estimation based on the distance between the signal extremums is more preferred. The results of computer modeling of the influence of the joint gap on the parameters of the magnetic signal qualitatively coincide with the results of field measurements made at inspection speeds up to 60 km/h.

Coal dust dispersion with the moving conveyance in a high-rise building for the mine hoist system.

The present study investigates dust generated from the unloading process in a high-rise building for the mine hoist system and analyzes dust dispersion with the moving conveyance in the building. First, the gas-solid two-phase flow in the building was investigated based on the CFD-DPM method. In particular, the moving conveyance was considered in detail and treated via thedynamic mesh technology. Then, the airflow and dust distribution were investigated in the building. The airflow and the dust concentration at selected points show good agreement with the relative results of field measurements by ourselves. It is found that the descending conveyance significantly influences the surrounding flow field and the spatial and temporal distribution of dust. Dust concentration before the dust source (2 m × 2 m) is high, which extends downward with the conveyance. Dust concentration of the lower floors increases obviously when compared with that of the condition without the movement of the conveyance. The descending velocity of the conveyance also affects the amount of PM2.5 discharged from the return air outlet. The fitting functions are provided to predict PM2.5 emissions to the surrounding atmosphere. The research results are of great significance for the improvement of the dust control system for cleaner production technology.

Thermal energy simulation of PCM-based radiant floor cooling systems for naturally ventilated buildings in a hot and humid climate

This study investigated the applicability of a thermal energy simulation (TES) for a naturally ventilated building in which a phase change material (PCM)-based radiant floor cooling system was installed. The TES was conducted to determine influential factors to maximize the thermal storage effect of PCMs in the building throughout a year in a hot and humid climate. First, the thermal properties of a full-scale PCM product were measured using the heat flow method. This measurement clearly captured the hysteresis of the PCM depending on the heating and cooling rates; thus, the enthalpy–temperature curve under slow heating and cooling rates was determined for the TES. Based on the results of the PCM measurement, the EnergyPlus-based TES model was validated by comparing it with the results of field measurement at a full-scale experimental building with natural ventilation in Indonesia and a computational fluid dynamics (CFD) simulation coupled with the heat balance analysis. Good correlations (up to R2 = 0.99) were observed in the air and floor surface temperatures between the measurement and TES simulation. Additionally, the TES had a similar accuracy as the coupled CFD, which considers spatial wind and temperature distribution. The results of the annual simulation showed that the proposed PCM-based radiant floor cooling system with night ventilation achieved a thermal comfort period of up to 68.5% a year. Furthermore, a reasonable annual average utilization rate of approximately 70% can be determined to maintain a low floor surface temperature throughout a year.

Methane Emission from Lakes in the North of Western Siberia

The paper presents the results of field measurements of methane fluxes into the atmosphere from thermokarst lakes located on the Russian Federation territory on the three key sites: foothills of the Polar Urals, coast of the Kara Sea and the northwestern part of the Yamal Peninsula. A total of 13 lakes were studied and about 500 methane fluxes were measured by the floating chamber method. The results showed most of the fluxes does not exceed 8 mg CH4 m–2 h–1. For more significant values, a statistically significant correlation with the wind speed was revealed, which largely determines the intensity of gas exchange on the “water-atmosphere” boundary. The exceptions are measurements in zone of lake methane seeps. For most lakes, the greatest scatter of measured fluxes was observed in the shallow part. The diurnal dynamics of methane fluxes was approximated by a sinusoidal function. For the lakes presented in the work, the range of emission assessment is 0.23–775.38 g CH4 h–1. Obtained results are important material for estimating regional methane emission from the surface of thermokarst lakes in the tundra zone.

Flood Sedimentology for Future Floods Mitigation in North Luwu, Sulawesi, Indonesia

A sedimentological study after the flash floods that hit North Luwu on July 13, 2020, has been carried out on three affected rivers, namely the Masamba River, the Radda River, and the Binuang River. The study aims to determine the sedimentological impact of the 2020 flash flood disaster, including sedimentation rate, annual bedload sediment volume, and total sediments, which will be used as a reference for future mitigation consideration. The study is based on fieldwork for data collection and laboratory analysis. The results of field measurements and laboratory analysis are then processed by calculating the sedimentation rate at the annual discharge, the bedload sediment volume, and the total estimated sediment accumulated by the flash flood. Sedimentation rate analysis was performed using the Ackers-White formula, and flood delineation was processed using HEC-RAS software. The climatological data from the climatology station at Andi Djemma Airport were used to calculate the river discharge. It is estimated that the volume of bedload sediment in the Binuang River is 16,194,168 m3/year, that of the Masamba River is 7,852,061 m3/year, and that of the Radda River is 4,003,011 m3/year. The volume of sediment brought by flash flood sedimentation in the Radda River is 9,141,608.39 m3, while that in the Masamba River is 55,131,761.29 m3, and that in the Binuang River is 136,838,603.61 m3. The total estimated sedimentation generated by the flash flood on the three rivers on July 13, 2020, is 222,476,966 m3. Based on the study, zonation for vulnerability levels is designed for a future mitigation scheme. The zonation can be classified into three zones: 1) the highly affected zone; 2) the moderately affected zone; and 3) the least affected zone, with special purposes in each zone. It is strongly recommended that future disaster settlement and infrastructure reconstruction policies be based on this zone to reduce disaster risk. Doi: 10.28991/CEJ-2023-09-04-011 Full Text: PDF

Greenhouse gas emissions from natural ecosystems of the Norilsk Industrial District

This paper describes the results of field measurements of methane and carbon dioxide fluxes from natural and anthropogenic-modified ecosystems located on the Norilsk industrial district. Previously, such studies have not been conducted in the area. The study points are located in different landscape regions determined by various conditions of permafrost formation. Most of the study area is located within the zone of predominantly continuous permafrost distribution. Six landscape regions were identified. Methane and carbon dioxide fluxes were measured at selected key sites typical for each region. When selecting the study points, the variety of conditions affecting methane and carbon dioxide emissions was considered. First, these include soil type (mineral or peat) and local moisture conditions. Methane and carbon dioxide fluxes were measured by dart static chamber method. Measurements of greenhouse gas concentrations in the chamber were carried out by a portable gas analyzer Li-7810 (Li-COR, USA). The results obtained show significant variability in greenhouse gas emissions for different ecosystem types. Methane uptake by soils is recorded on mineral soils and dry parts of bog ecosystems. Positive methane emissions are typical for watered areas of bog ecosystems and lakes with maximum values in the hollows. Methane fluxes range from slightly negative in dry bog areas with a median of -0.026 mgCH4/m2/h to emissions of 0.802 mgCH4/m2/h as the median for watered areas of bog ecosystems. Carbon dioxide fluxes are inversely correlated with the ecosystem moisture content and have a range from 51.6 mgCO2/m2/h (median for lakes) to 576 mgCO2/m2/h (median for mineral soils). A medium strength correlation was found between surface air temperature and intensity of methane uptake by mineral soils was found. Probability density distributions of methane and carbon dioxide fluxes have different forms.

Determination of precipitation intensity based on data from dual polarisation radar

The paper presents the results of a preliminary study of cloudiness area with hail precipitationbased on data from a dual-polarisation electromagnetic wave radar operating in Rzeszów-Jasionkawhich is one of eight meteorological radars belonging to the POLRAD managed by the Institute ofMeteorology and Water Management – National Research Institute. Atmospheric dual-polarisationwave scanning provides a significant radar data that accurately describes detected meteorologicalobjects, including the sizes of cloud and precipitation particles. The conducted research enabled usa qualitative and quantitative description of cloudy zones with precipitation of variable intensity andvariable spatial and temporal distribution. Obtaining data on the structure of the cloud cover zonerequires the creation of new and non-standard imagery showing horizontal and vertical distributionsof radar reflectivity determined on the basis of measurements in the classic radar channel. Radar datawere processed using RAINBOW DART and RAPOK software. Completely new rainfall datasetswere generated for the selected region with consistency of location and observation date, in whichprecipitation intensity, phase state, and environmental factors were taken into account. Developedvertical cross-sections of the atmosphere along the set route provided information on the structureand activity of the studied storm cell and the precipitation core present. Precipitation intensity wasdetermined from the Marshall‒Palmer, Joss and Muchnik correlations, which used radar reflectivityat heights of 1 km, 1.5 km, and 2 km above the ground surface, taking into account the freezing level.The paper presents a comprehensive analysis of the hail situation based on synoptic data and imagesof hail intensity and hail probability. It was shown that, available in the meteorological data exchangenetwork, the standard images of precipitation intensity generated in each case based on the Marshall‒Palmer correlation for radar reflectivity at a height of 1 km above the ground surface may containerrors, which require changes in calculation algorithms to be minimised. At this stage of the research,other dependencies were used in the calculations, which took into account the type of precipitation.On the other hand, data on the structure of the studied storm cell allowed us calculations based on thevalues of radar reflectivity determined at different levels in the rain core. The analysis of the obtainedradar precipitation data was carried out on the basis of both syn-optic and climatic data for the studiedregion. In the next stage of research, the results of field meas-urements carried out in regions with anextensive network of direct precipitation measurements will be used. The results of these studies willallow us to recommend empirical relationships for determining precipitation intensity dependingon the type of precipitation, the structure of the precipitation cloud and environmental conditions.Keywords: civil engineering, geodesy and transport, remote sensing of the atmosphere, dual polarisationradar, radar reflectivity, rainfall intensity, hail

Evaluation of Surface Crack Development and Soil Damage Based on UAV Images of Coal Mining Areas

Coal mining is necessary for the development of society but at the same time causes ecological damage that must also be repaired based on science. In the arid and semi-arid regions of northwest China, surface cracks are one of the major geo-environmental problems caused by coal mining, and studies are urgently needed to determine how to effectively repair them in a scientific manner. The rapid development of unmanned aerial vehicle (UAV) remote sensing technology in recent years has resulted in a good source of data for acquiring feature information on surface cracks. Existing studies mainly focus on high-precision crack extraction methods, and there are few studies on the methods for evaluating cracks. However, clarifying the degree of cracks requiring repair and what repair measures are required through scientific and reasonable evaluation methods is necessary to formulate effective crack repair and land reclamation plans. Given these considerations, in this study, the degree of both crack development and soil damage were evaluated based on the crack extraction results of UAV images. Based on the results of indoor experiments and field measurements, the grading criteria for the degree of crack development and soil damage were constructed. Crack density was used as the evaluation index for the degree of crack development (slight: <0.4%, moderate: 0.4–2%, severe: >2%). The distance between soil and cracks was the basis of the evaluation index for the soil damage degree (severe damage area: <0.6 m; slight damage area: 0.6–1.2 m; no obvious damage area: >1.2 m). Through the results from evaluating the degree of both crack development and soil damage in the study area, it was found that the degree of crack development was mainly moderate and located in the northern crack zone of the study area, with the cracks and damaged soil showing a striped pattern in the east-west direction. Combining the evaluation results of crack development and soil damage, the ecological restoration model of “natural restoration + crack filling + water supplementing + vegetation planting” is proposed. We conclude that crack repair should be applied in areas where moderate and severe cracks have developed, whereas soil repair should target the soil within 1.2 m of the cracks in the above area. This study is the first attempt to construct and evaluate the classification criteria of crack development degree and soil damage degree from the perspective of cracks and soil, and the results are of guiding significance for land reclamation in mining areas.

Coevolution mechanism and branch of pillar‐overburden fissures in shallow coal seam mining

AbstractThe large‐scale mining of coal resources promotes the formation of section coal pillar groups between working faces. The overlying strata are supported by coal pillars, which leads to the formation of a unique fracture‐bearing structure in the key stratum, resulting in the evolution of fissures (cracks) and a generally high load on the supports. Studying the fracture‐bearing structure formed by coal pillars and overlying strata (fissures) is the basis for realizing rational mining of working faces. Here, the evolution characteristics of coal pillar‐overburden rock (fissures) in shallow coal seam mining and the working resistance of the support with stable fracture bearing structure of section coal pillar and overburden rock were studied in the No. 1‐2 coal mining of Longhua Coal Mine in Shenmu City, Northern Shaanxi. The fissure evolution characteristics on both sides of the coal pillar and the fracture‐bearing structure of the rock stratum were obtained by physical similarity simulation experiment. The mechanical calculation model of the coal pillar‐overburden rock (fissure) structure was established by theoretical derivation and calculation, and the working resistance of advanced support with a stable mechanical structure was studied. The research shows that the fracture evolution and rock fracture characteristics of a shallow coal seam mining face can be divided into three zones. Through the reanalysis of the mechanical structure of coal pillar‐overburden rock (fissure), the combined mechanical structure of the subkey stratum consisting of a lagging broken step rock beam structure and the main key stratum consisting of a hinged rock beam structure was obtained. Combined with the failure characteristics of the section coal pillar, a mechanical structure calculation method suitable for the bearing characteristics of section coal pillar support in shallow coal buried layers was obtained, and the field measurement results were verified.

Transient Electromagnetic Process in the Waters of the Sea Shelf with Axial and Equatorial Electric Installations and a Field Experiment

A change in the non-stationary electromagnetic (EM) signal over the conducting polarizable Earth covered by sea water on measuring lines located in the axial and equatorial regions of the source – a pulsed horizontal electric line (HEL) – is considered. When the HEL operates under pulsed conditions, it creates a galvanic and eddy current in the medium. If the medium affected by the HEL is heterogeneous, both influences lead to the separation of bound charges. After attenuating the impact of an artificial source, relaxation (depolarizing) processes of various nature appear in such a medium, manifesting themselves, in particular, in the form of an EM signal. As a result, the transient process recorded by the grounded line after the pulsed effect of the HEL is at least a superposition of three components: the transient electromagnetic (TEM) signals, galvanically induced polarization (GIP) and inductively induced polarization (IIP). As the contribution of the TEM field component to the overall signal decreases, the IP signal is manifested in the transient process by a change in the time response of the decay, to the point where the signal reverses polarity. As shown earlier by numerical simulations for the axial region of the HEL, the manifestation of the IIP signal at late transient process times, for most of the geoelectric conditions on land, is invisible against the GIP manifestation (Ageenkov et al., 2020). These calculations also show that in the axial region, the GIP signal manifests itself in the form of a deceleration of the transient process rate, and the IDP signal – an acceleration of the decay rate, to the point where the signal changes its sign. Field measurements performed by the aquatic differential-normalized method of electrical prospecting (ADNME), which uses axial electrical installations, record transient processes with a change in the time response of the decay: it becomes more delayed or, vice versa, runs faster and may be accompanied by a change in the polarity of the signal. In other words, measured signals of different forms are observed, which are presumably associated with the manifestation of the GIP or IIP signals. The relevance of the publication lies in the need to explain the results of field measurements performed offshore, to understand the relationship between the course of the transient process and the geoelectric conditions existing in the water area. And in general, to describe the formation of the transient response of the medium in the axial and equatorial region of the HEL for the conditions of aquatic geoelectrics. The calculated signal for axial and equatorial electrical installations with several spacings under the conditions of the sea shelf water area is studied when the installation is located on the surface of and inside the water layer, and on the seabed of the water area – on geological formations. For axial installations, calculations are made of the quantities used in the ADNME: the transient process ΔU(t), the finite difference of the transient process Δ2U(t) and the transformant P1(t) – the ratio of Δ2U(t) to ΔU(t). For equatorial installations, the signal ΔU(t). is calculated. The signals of a two-layered model of the medium with polarizable and non-polarizable bases are compared.

Estimasi Produksi Gas Metana Untuk Pemanfaatan Sebagai Sumber Energi Di TPA Talang Gulo, Jambi

Landfills (TPA) are a significant source of methane emissions into the atmosphere. In Indonesia, the estimation of methane gas production from a landfill has not been widely carried out. The purpose of this research is to measure production and measure the concentration of methane gas emitted into the atmosphere, assess methane gas emissions as an energy source, and analyze the potential costs and benefits of electrical energy that can be generated from methane gas emissions at the Talang Gulo TPA. The emission data obtained can be used as material for analysis to create a project for developing a gas processing system from a landfill. This estimation approach is carried out in three ways, namely prediction with LandGEM-v302 software, field measurements with methane flux and utilization of methane gas production as an energy source. The LandGEM-v302 simulation results obtained a total landfill gas of 29.96 Gg/year consisting of CH4 of 8.002 Gg/year, CO2 of 21.96 Gg/year and NMOC (non-methane organic compounds) of 0.344 Gg/year. The results of field measurements on the surface of the closed chamber TPA obtained CH4 emissions from TPA Talang Gulo of 4.75 Mg/year. The different characteristics of the landfill surface greatly affect the gas emissions released into the atmosphere. Moisture conditions or water content in the waste also affect the methane emission rate. The electricity potential from methane gas is 15.718 MW so that the cost benefit analysis shows an NPV of Rp. 6,028,622,852.18, B/C Ratio of 0.00196 and IRR of 2.445%.

Performance evaluation of a single-side windcatcher in the transitional seasons (case study: Khousf town, Southern Khorasan Province, Iran)

PurposeLife experience in hot and arid areas of Iran has proved that in the transitional seasons (spring and autumn) in which the climate is not too hot, passive cooling systems such as windcatchers (baadgir) have functioned well. This paper intends to investigate the efficiency of a single-side windcatcher as a passive cooling strategy; the case study is the Bina House windcatcher, located in Khousf town, near Birjand city, Iran.Design/methodology/approachTo achieve the aim, air temperature, relative humidity, wind data and mean radiant temperature were measured by the related tools over five days from September 23 to October 23. Then, the thermal performance of the windcatcher was examined by analyzing the effects of all these factors on human thermal comfort. Quantitative assessment of the indoor environment was estimated using DesignBuilder and its computational fluid dynamics (CFD) tool, a thermal comfort simulation method to compare the cooling potential of the windcatcher. Windcatcher performance was then compared with two other common cooling systems in the area: single-side window, and evaporative cooler.FindingsThe results showed that both windcatcher and evaporative cooler can provide thermal comfort for Khousf residents in the transitional seasons; but the difference is that an evaporative cooler needs to consume water and electricity power, while a windcatcher is a passive cooling system that uses clean energy of wind.Originality/valueThe present study, by quantitative study of single-side windcatchers in a desert region, measured the climatic factors of a historical house and compared it with thermal comfort criteria. Therefore, the results of field measurements were analyzed, and the efficiency of the windcatcher was compared with two other cooling systems, namely single-side ventilation and evaporative cooler, in the two seasons of summer and autumn (transition seasons).