Intensity fluctuations are frequently observed in different regions and structures of the solar corona.These fluctuations may be caused by magneto-hydrodynamic(MHD)waves in coronal plasma.MHD waves are prime candidate...Intensity fluctuations are frequently observed in different regions and structures of the solar corona.These fluctuations may be caused by magneto-hydrodynamic(MHD)waves in coronal plasma.MHD waves are prime candidates for the dynamics,energy transfer,and anomalous temperature of the solar corona.In this paper,analysis is conducted on intensity and temperature fluctuations along the active region coronal loop(NOAA AR 13599)near solar flares.The intensity and temperature as functions of time and distance along the loop are extracted using images captured by the Atmospheric Imaging Assembly(AIA)instrument onboard the Solar Dynamics Observatory(SDO)space telescope.To observe and comprehend the causes of intensity and temperature fluctuations,after conducting initial processing,and applying spatial and temporal frequency filters to data,enhanced distance-time maps of these variables are drawn.The space-time maps of intensities show standing oscillations at wavelengths of 171,193,and 211A with greater precision and clarity than earlier findings.The amplitude of these standing oscillations(waves)decreases and increases over time.The average values of the oscillation period,damping time,damping quality,projected wavelength,and projected phase speed of standing intensity oscillations are in the range of 15-18 minutes,24-31 minutes,1.46″-2″,132″-134″,and 81-100 km s^(-1),respectively.Also,the differential emission measure peak temperature values along the loop are found in the range of 0.51-3.98 MK,using six AIA passbands,including 94,131,171,193,211,and 335?.Based on the values of oscillation periods,phase speeds,damping time,and damping quality,it is inferred that the fluctuations in intensity are related to standing slow magneto-acoustic waves with weak damping.展开更多
Gas flaring is one of the major problems in the world. It consumes useful natural resources and produces harmful wastes, which have negative impacts on the society. It is one of the most tedious energy and environment...Gas flaring is one of the major problems in the world. It consumes useful natural resources and produces harmful wastes, which have negative impacts on the society. It is one of the most tedious energy and environmental problems facing the world today. It is a multi-billion dollar waste, a local environmental catastrophe and environmental problem which has persisted for decades. From the year 1996-2010, in Nigeria, 12,602,480.25 million ft3 of natural gas was flared (NNPC). This is equivalent to losing about 12,967.952 × 1012 Btu of energy that would have been used to generate power or converted to other forms of energy. In 2015, the World Bank estimated that 140 billion cubic meters of natural gas produced with oil is flared annually, mostly in developing countries without gas processing infrastructures, or other means of utilizing the produced gas. It is widely known that flaring or even, venting of gas contributes significantly to greenhouse gas emissions, with negative impacts on the environment. Thus, alternative solutions to reduce or utilize the quantity of gas flared are crucial issues. Therefore, the need to study and provide detailed understanding of these alternative solutions to gas flaring is important. This paperoutlined the harmful effects of gas flaring and the different possible alternatives to gas flaring. The proposed alternative solutions are gas for secondary oil recovery, feedstock for petrochemical plants, domestic uses, LNG & CNG, as well as energy conservation by storing as gas hydrate for future use or other purposes. Gas hydrate is stable above the freezing point of water and sufficiently high pressure. It is relatively stable under its saturation temperature and pressure and also much denser than normal ice. This property of gas hydrate can be experimentally investigated and capitalized on, to effectively store natural gas as hydrate for energy conservation instead of flaring the gas wastefully. The alternative solutions will convincingly reduce and in the nearest future stop gas flaring globally.展开更多
This work deals with the multi-faceted impact of gas flaring on a global scale and the different approach employed by researchers to measure gas flared and its resulting emissions. It gives an overview of methods empl...This work deals with the multi-faceted impact of gas flaring on a global scale and the different approach employed by researchers to measure gas flared and its resulting emissions. It gives an overview of methods employed by these researchers in the oil and gas industry, academia and governments in attempt to determine ways of measuring and reducing gas flaring and its emission drastically. This approach so far includes analytical studies, numerical studies, modeling, computer simulations, etc. the goal behind each study being to mitigate the effects of gas flaring. The outcome indicates that there is a seemingly absence of a single global method, emission factor and estimation procedure used in the oil and gas industry all over the world to determine the volume of gas flared and its emissions be it from complete or incomplete combustion, sweet or sulphur present hydrocarbons and this poses a continuous problem in determining the actual impact of gas flaring and its emissions on human and its role in environmental degradation both at a local and global level. An attempt has also being made to cover up-to-date trends in gas flaring and current developments in some of the most flared countries.展开更多
This study investigated the effects of gaseous emissions from crude storage tank and gas flaring on air and rainwater quality in Bonny Industrial Island. Ambient air quality parameters, rainwater and weather parameter...This study investigated the effects of gaseous emissions from crude storage tank and gas flaring on air and rainwater quality in Bonny Industrial Island. Ambient air quality parameters, rainwater and weather parameters were collected at 60 m, 80 m, 100 m, 200 m and control plot for 4 weeks at the Bonny. Rainwater parameters were investigated using standard laboratory tests. Data analyses were done using Analysis of variance, pairwise t-test and Pearson’s correlation statistical tools. Results show that emission rates, volatile organic compound (VOC) noise and flare temperature decreased with increasing distance from flare points and crude oil storage tanks. Findings further revealed the emission rates varied significantly with distance away from the gas flaring point (F = 6.196;p = 0.004). The mean concentration of pollutants between gas flare site and crude oil storage tank showed that CO (0.02 ± 0.001 - 0.002 ±0.001), SPM (0.011 ± 0.001 - 0.01 ± 0.001), VOC (0.005 ± 0.001 - 0.01 ± 0.001) and NO<sub>2</sub> (0.04 ± 0.001 - 0.005 ± 0.000) had significant variations (p > 0.05) with CO, O<sub>3</sub> and NO<sub>2</sub> having higher concentrations at the gas flare site while SPM, and VOC were higher around the crude oil storage tank site. Wind turbulence was higher around the gas flaring point (4.93 TKE) than the crude oil storage tank (4.55 TKE). Similarly, there was significant variation in the sun radiation, precipitation, and wind speed caused by gas flaring (1582.25 w/m<sup>2</sup>, 436.25 mm, 0.53 m/s) and crude oil storage tank (1536.25 w/m<sup>2</sup>, 3.91.41 mm, 0.51 m/s). There were also significant variations in flared temperature (F = 22.144;p = 0.001);NO<sub>2</sub> (F = 8.250;p = 0.001), CO (F = 6.000;p = 0.004) and VOC (F = 5.574;p = 0.006) with distance from the gas flaring point. The variation in the rainwater parameters with distance from the gas flaring indicated significant variations in pH (F = 5.594;p = 0.006). The study showed that the concentration of VOC and particulates were high in the supposedly control area which is perceived to be safe for human habitation. Significant variations exist in emission rate (p = 0.015), flare temperature (p = 0.001), NO<sub>2</sub> (p = 0.003), VOC (p = 0.001), noise (p = 0.041), hydrogen carbonate (p = 0.037) and chromium (p = 0.032) between the gas flaring and crude oil storage tank. Regular monitoring is advocated to mitigate the harmful effects of the pollutants.展开更多
This paper discusses the thermodynamic and environmental assessment of flared gases in an oil field. The oil field for the case study is located in the Niger Delta region of Nigeria. The data required for this report ...This paper discusses the thermodynamic and environmental assessment of flared gases in an oil field. The oil field for the case study is located in the Niger Delta region of Nigeria. The data required for this report were obtained during a nine-year period (2008-2016), which revealed production volumes, flared volumes, operating temperatures and pressures, gas compositions, gas density, and flow rates. With the data and the aid of fundamental thermodynamic equations and MATLAB program codes, analysis was carried out on combustion to ascertain the amount of flue gases. Analyses revealed that a total of 1.99175 × 1011 standard cubic feet of gas was flared during the said period, generating anthropogenics estimated at 582,319,618.1825 m3 (≈1.046 Mt) of CO2, 1,077,510,054.31 m3 (≈2.0 Mt) of water vapour, 14,960,560.91 m3 of methane emitted and contaminated the atmosphere creating serious environmental concerns. Further analyses also showed that the approximate adiabatic flame temperature is about 1965°C for the field under investigation. Exergy analyses carried out also revealed that a total of 3.6099 × 1013 kJ (36.099 TJ) of exergy was available which would have translated to 1.0189 × 1010 kWh of electrical energy for the period under investigation. Conclusively, some measures that can be taken to prevent gas flaring are that every new project on oil and gas should incorporate technical details of gas gathering and utilization plan at the conceptual and design phases of projects for gas commercialization, establishment of more gas-to-power project for gas utilization. Also Carbon capture technology should be enhanced, although the best option is flaring out based on the astronomical amount of carbon (IV) oxide and other greenhouse gases depicted by the results. The entire work and results showed that gas flaring is undesired and pernicious because it has thermal, environmental and economic consequences.展开更多
Oil spills and gas flaring are major environmental problems and pose major source of adverse health outcomes to communities hosting oil wells and natural gas. As oil is spilt and gas is flared;air, soil and water in a...Oil spills and gas flaring are major environmental problems and pose major source of adverse health outcomes to communities hosting oil wells and natural gas. As oil is spilt and gas is flared;air, soil and water in affected communities are polluted. Due to this, members of these communities are exposed to higher health risks. One vulnerable group that is usually affected in this regard is pregnant women. This systematic review identified and reviewed past studies on oil pollution and different types of pregnancy outcomes within a twenty-year gap, which is between 1999 and 2019. The review also discussed the exposure pathways of oil pollution. From a literature search on scientific databases conducted in August 2019 for articles relating to the objectives of the review, data were extracted from articles which met the inclusion criteria and contents were systematically analyzed based on types of pregnancy outcomes. This review showed that oil spill and gas flaring may put pregnant women at high risk of hypertensive disorders of pregnancy, gestational diabetes mellitus, maternal depression, miscarriages via three pathways. This review may be of some use in making policy in this area.展开更多
The threat to human, fauna and flora life posed by pollution due to gas flaring cannot be over-emphasized. Gas flared often resulted in some environmental degradation, one of such influence is soil pollution and poor ...The threat to human, fauna and flora life posed by pollution due to gas flaring cannot be over-emphasized. Gas flared often resulted in some environmental degradation, one of such influence is soil pollution and poor crop yield. This study examined the effect of gas flaring on soil and cassava productivity in Ebedei, Ukwuani LGA, Delta State. For the purpose of data collection, five (5) experimental sites were systematically selected around the flare site in Ebedei and a control site at Obiaruku. Soil samples were collected at surface 0 - 10 cm and 10 - 20 cm at distance of 50 m, 100 m, 150 m, 200 m and 250 m apart respectively away from the bund wall of the flare. The data generated were analysed using multiple regression and paired t-test analyses. The study revealed that the soils found in Ebedei have high composition of sand and soil temperature and are acidic. The soil electrical conductivity, Phosphorous, Nitrogen, Potassium and Sodium were very low. More so, the yield of cassava increases with a corresponding increase in distances from flare site. The first hypothesis revealed that there is significant variation in soil nutrients as distance increases from gas flare sites. This is evident from F value of 234.99 which is greater than the critical table value of 4.39. Furthermore, as flare distance increases, so also the organic carbon, electrical conductivity and Nitrogen increase. The second hypothesis revealed that there is a significant difference in cassava yield at gas-flared area and the non-flared area which is evident at t (6.032) is greater than the critical table (1.895) at P 0.05. It is therefore recommended that Government and FEPA should enact environmental Policies and revisit and review existing environmental and oil drilling laws in Nigeria with a view of updating them to international and environmental friendly standards.展开更多
The extent to which a country develops is anchored around its resources;and this is evidenced in how the revenue derived from natural resources (especially the oil and gas industries) has influenced national developme...The extent to which a country develops is anchored around its resources;and this is evidenced in how the revenue derived from natural resources (especially the oil and gas industries) has influenced national development strategies. This notwithstanding, the existence of natural resources does not always translate to development, as these often times lead to complacency and mismanagement;Nigeria may have suffered from this. This paper establishes the impact of gas production, utilization, and flaring on the estimated monetary value of the goods and services produced in Nigeria (GDP), using multiple linear regression analysis. The result shows that while gas utilization has a positive impact on the nation’s GDP, gas production and flaring are negatively associated with GDP. The paper concludes that for these to positively stimulate economic growth, there is need to invest more in infrastructure in the industry, and review the regulatory framework guiding operations of the oil and gas industry.展开更多
Since the discovery of oil and gas in Nigeria in 1956, much gas has been flared because the operators pay little or no concern to its utilization, and as such, trillions of dollars have been lost. In this paper, a mod...Since the discovery of oil and gas in Nigeria in 1956, much gas has been flared because the operators pay little or no concern to its utilization, and as such, trillions of dollars have been lost. In this paper, a model is proposed using Time Series Regression Model (TSRM) and Time Series Neural Network (TSNN) to model the production, utilization and flaring of natural gas in Nigeria with the ultimate aim of observing the trend of each activity. The results show that TSNN has better predictive and forecasting capabilities compared to TSRN. It is also observed that the higher the hidden neurons, the lower the error generated by the TSNN.展开更多
This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average m...This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average mean precipitation data sourced from CHRS at the University of Arizona and carbon dioxide emissions data from NASA’s AIRS in Giovanni,spanning from July 2002 to November 2011.To carry out the analysis,ArcGIS 5.0 and SPSS 25,employing Inverse Distance Weighting(IDW),were employed to assess CO_(2) emissions and rainfall for both November and July during the period from 2002 to 2011.Over the course of this study,it was observed that CO_(2) emission exhibited an upward trend,increasing from 327.5226 parts per million(ppm)in July 2002 to 390.0077 ppm in November 2011.Simultaneously,the rainfall demonstrated an increase,rising from 56.66 millimeters to 390.78 millimeters for both July and November from 2002 to 2011.Noteworthy findings emerged from the correlation analysis conducted.Specifically,from July 2000 to 2011,there was a weak positive correlation(0.3858)observed between CO_(2) emissions and minimum rainfall,while a strong negative correlation(–0.7998)was identified for maximum rainfall values.In November,both minimum and maximum CO_(2) emissions displayed strong negative correlations with rainfall,with coefficients of–0.8255 and–0.7415,respectively.These findings hold significant implications for comprehending the environmental dynamics within the Niger Delta.Policymakers and stakeholders can leverage this knowledge to formulate targeted strategies aimed at mitigating CO_(2) emissions and addressing potential climate change-induced alterations in rainfall patterns.展开更多
Here,we study the temperature structure of flaring and non-flaring coronal loops,using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Obse...Here,we study the temperature structure of flaring and non-flaring coronal loops,using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Observatory.We use data for loops of an X2.1-class-flaring active region(AR 11283)during 22:10 UT until 23:00 UT,on 2011 September 6;and a non-flaring active region(AR 12194)during 08:00:00 UT until 09:00:00 UT on2014 October 26.By using the spatially synthesized Gaussian differential emission measure(DEM)forward-fitting method,we calculate the peak temperatures for each strip of the loops.We apply the Lomb–Scargle method to compute the oscillation periods for the temperature series of each strip.The periods of the temperature oscillations for the flaring loops ranged from 7 to 28.4 minutes.These temperature oscillations show very close behavior to the slow-mode oscillation.We observe that the temperature oscillations in the flaring loops started at least around10 minutes before the transverse oscillations and continue for a long time duration even after the transverse oscillations ended.The temperature amplitudes increased during the flaring time(20 minutes)in the flaring loops.The periods of the temperatures obtained for the non-flaring loops ranged from 8.5 to 30 minutes,but their significances are less(below 0.5)in comparison with the flaring ones(near to one).Hence the detected temperature periods for the non-flaring loops’strips are less probable in comparison with the flaring ones,and maybe they are just fluctuations.Based on our confined observations,it seems that the flaring loops’periods show more diversity and their temperatures have wider ranges of variation than the non-flaring ones.More accurate commentary in this respect requires more extensive statistical research and broader observations.展开更多
We have studied the spectral behavior of theⅡPeg binary system in the ultraviolet band by using International Ultraviolet Explorer(IUE)observations over the period 1979-1993.The ultraviolet observations reveal indica...We have studied the spectral behavior of theⅡPeg binary system in the ultraviolet band by using International Ultraviolet Explorer(IUE)observations over the period 1979-1993.The ultraviolet observations reveal indication of flare activity in both chromosphere and transition region with their enhanced emission lines.Before and after the flare activity the ultraviolet emission lines show low,intermediate and high flux.The spectral behavior is compared with previous studies.We detect prominent flare activity in 1989,1990 and 1992.Before and after this period there is a gradual clear decrease in the level of activity.The reddening ofⅡPeg was determined from a 2200?absorption feature to be E(B-V)=0.10±0.02.We ascertained the average mass loss rate to be≈1×10^(-8)M_(☉)yr^(-1),and an average ultraviolet luminosity to be≈6×10^(29)erg s^(-1).We attributed the spectral variations to a cyclic behavior of the underlying magnetic dynamo and the prominent activity can be interpreted by the model of a two-ribbon flare.展开更多
During the lifetime of AR 12673,its magnetic field evolved drastically and produced numerous large flares.In this study,using full maps of the Sun observed by the Solar Dynamics Observatory and the Solar Terrestrial R...During the lifetime of AR 12673,its magnetic field evolved drastically and produced numerous large flares.In this study,using full maps of the Sun observed by the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory,we identified that AR 12673 emerged in decayed AR 12665,which had survived for two solar rotations.Although both ARs emerged at the same location,they possessed different characteristics and different flare productivities.Therefore,it is important to study the long-term magnetic evolution of both ARs to identify the distinguishing characteristics of an AR that can produce large solar flares.We used the Space-weather Helioseismic and Magnetic Imager Active Region Patch data to investigate the evolution of the photospheric magnetic field and other physical properties of the recurring ARs during five Carrington rotations.All these investigated parameters dynamically evolved through a series of solar rotations.We compared the long-term evolution of AR 12665 and AR 12673 to understand the differences in their flare-producing properties.We also studied the relation of the long-term evolution of these ARs with the presence of active longitude.We found that the magnetic flux and complexity of AR12673 developed much faster than those of AR 12665.Our results confirmed that a strong emerging flux that emerged in the pre-existing AR near the active longitude created a very strong and complex AR that produced large flares.展开更多
Craniometaphyseal dysplasia(CMD),a rare craniotubular disorder,occurs in an autosomal dominant(AD)or autosomal recessive(AR)form.CMD is characterized by hyperostosis of craniofacial bones and metaphyseal flaring of lo...Craniometaphyseal dysplasia(CMD),a rare craniotubular disorder,occurs in an autosomal dominant(AD)or autosomal recessive(AR)form.CMD is characterized by hyperostosis of craniofacial bones and metaphyseal flaring of long bones.Many patients with CMD suffer from neurological symptoms.The pathogenesis of CMD is not fully understood.展开更多
The experimental studies of the flaring gate pier applied on the surface spillway in a high-arch dam show that a shock-wave will appear when the pattern of the flow is kept as super-critical. Meanwhile, the water dept...The experimental studies of the flaring gate pier applied on the surface spillway in a high-arch dam show that a shock-wave will appear when the pattern of the flow is kept as super-critical. Meanwhile, the water depth at the outlet increases significantly, the flow moves downward in different directions, and the plunging jet is in a narrow and long shape, with a full longitudinal diffusion. In addition, the variation of the flaring gate pier design parameters affects little the discharge capacity of the surface spillway, these parameters including the contraction ratio fl, the contraction angle c~ and the spillway chute angle O. The pressure on the bottom of the spillway increases along the way and reaches the maximum before the outlet, and then decreases rapidly. Due to the flow impacting, the pressure on both sidewalls increases abruptly at the turning line of the flaring gate pier. To see the characteristics of the flow in the flaring gate pier, a simple calculation method is suggested based on the conversation of energy and mass, and the calculation methods for the jet trajectory and the horizontal length in air are also proposed. The results are found in good agreement with experimental data.展开更多
The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aer...The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aerated cavity occured behind piers. The interaction of the weir head, the elevation difference between crest and chamber outlet, the first step height, the slopes of weir end and step, and the size of cavity, was investigated, the expression was derived to characterize their relationship, and the corresponding curves were plotted. The comparison of the calculated and simulated results with the measured data was performed. When the slopes of step and weir end are equivalent, the relative height difference between the first and second steps becomes the main factor influencing the aerated cavity. These findings may be useful in practical applications.展开更多
A new-style flood discharging dam, which consolidates the flaring gate pier and the stepped spillway for discharging the flood through the dam surface, had been applied in China. The theoretical study on it is in a be...A new-style flood discharging dam, which consolidates the flaring gate pier and the stepped spillway for discharging the flood through the dam surface, had been applied in China. The theoretical study on it is in a beginning stage at present. The three-dimensional numerical simulation has not been reported. In this paper, the 3D numerical calculation on the two-phase flow of water and air with discharge per unit width 195m~ 3 /s· m is presented . The results indicate that there is negative pressure on the juncture of the spillway surface and the first step. There forms obvious longitudinal and transverse eddies on the steps and the velocity decreases obviously compared with the smooth spillway. The figures of the velocity distributions and the water-air two-phase flows are plotted. The results calculated on the pressure are in agreement with the experimental data. Based on the position of the negative pressure obtained from calculation, measurement points of pressure are arranged in physical model. The experimental results validate the existence of the negative pressure. Being an applied and trial study, the results obtained are of theoretical and practical significance.展开更多
Using the new soft X-ray data from the Macao Science Satellite-1,we studied a solar flare that occurred on 22 June 2023.We found that the centroids of the Ca(around 3.9 keV)and Fe(around 6.7 keV)line features exhibit ...Using the new soft X-ray data from the Macao Science Satellite-1,we studied a solar flare that occurred on 22 June 2023.We found that the centroids of the Ca(around 3.9 keV)and Fe(around 6.7 keV)line features exhibit a rapid shift toward higher energy channels during the flare's rising phase,followed by a gradual decrease during the decay phase.Through precise energy calibration,the centroids are determined with high accuracy.Temperature and velocity are then self-consistently derived by comparing the centroids with those calculated from the synthesized line features using the latest CHIANTI atomic database(ver.10.1).The calculated maximum velocity reaches up to 710±60 km s-1,which significantly exceeds the previously reported values.Our results suggest that the entire shift of soft X-ray lines may occur during the process of chromospheric evaporation.展开更多
The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatia...The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatial resolution than expected.In this paper,we developed the SDI point-spread function(PSF)and Image Bivariate Optimization Algorithm(SPIBOA)to improve the quality of SDI images.The bivariate optimization method smartly combines deep learning with optical system modeling.Despite the lack of information about the real image taken by SDI and the optical system function,this algorithm effectively estimates the PSF of the SDI imaging system directly from a large sample of observational data.We use the estimated PSF to conduct deconvolution correction to observed SDI images,and the resulting images show that the spatial resolution after correction has increased by a factor of more than three with respect to the observed ones.Meanwhile,our method also significantly reduces the inherent noise in the observed SDI images.The SPIBOA has now been successfully integrated into the routine SDI data processing,providing important support for the scientific studies based on the data.The development and application of SPIBOA also paves new ways to identify astronomical telescope systems and enhance observational image quality.Some essential factors and precautions in applying the SPIBOA method are also discussed.展开更多
This paper outlines the scientific goals and observational strategies of the Mini-SiTian Array.Mounted at Xinglong Observatory,the Mini-SiTian Array consists of three 30 cm telescopes and has been in operation since 2...This paper outlines the scientific goals and observational strategies of the Mini-SiTian Array.Mounted at Xinglong Observatory,the Mini-SiTian Array consists of three 30 cm telescopes and has been in operation since 2022.The large field of view,combined with the capability for multi-band photometric observations,enables the Mini-SiTian Array to perform rapid follow-up observations to identify optical counterparts of gravitational waves,capture the early light curves of tidal disruption events and supernovae,and monitor stellar flares,Be star outbursts,and cataclysmic variable stars,although its limiting magnitude is not very deep.By collaborating with the Xinglong2.16 m telescope and leveraging a real-time image processing pipeline,simultaneous photometric and spectroscopic observations could be performed to reveal their underlying physical mechanisms.The observational and research experience provides critical guidance for the implementation of the full-scale SiTian project in the future.展开更多
文摘Intensity fluctuations are frequently observed in different regions and structures of the solar corona.These fluctuations may be caused by magneto-hydrodynamic(MHD)waves in coronal plasma.MHD waves are prime candidates for the dynamics,energy transfer,and anomalous temperature of the solar corona.In this paper,analysis is conducted on intensity and temperature fluctuations along the active region coronal loop(NOAA AR 13599)near solar flares.The intensity and temperature as functions of time and distance along the loop are extracted using images captured by the Atmospheric Imaging Assembly(AIA)instrument onboard the Solar Dynamics Observatory(SDO)space telescope.To observe and comprehend the causes of intensity and temperature fluctuations,after conducting initial processing,and applying spatial and temporal frequency filters to data,enhanced distance-time maps of these variables are drawn.The space-time maps of intensities show standing oscillations at wavelengths of 171,193,and 211A with greater precision and clarity than earlier findings.The amplitude of these standing oscillations(waves)decreases and increases over time.The average values of the oscillation period,damping time,damping quality,projected wavelength,and projected phase speed of standing intensity oscillations are in the range of 15-18 minutes,24-31 minutes,1.46″-2″,132″-134″,and 81-100 km s^(-1),respectively.Also,the differential emission measure peak temperature values along the loop are found in the range of 0.51-3.98 MK,using six AIA passbands,including 94,131,171,193,211,and 335?.Based on the values of oscillation periods,phase speeds,damping time,and damping quality,it is inferred that the fluctuations in intensity are related to standing slow magneto-acoustic waves with weak damping.
文摘Gas flaring is one of the major problems in the world. It consumes useful natural resources and produces harmful wastes, which have negative impacts on the society. It is one of the most tedious energy and environmental problems facing the world today. It is a multi-billion dollar waste, a local environmental catastrophe and environmental problem which has persisted for decades. From the year 1996-2010, in Nigeria, 12,602,480.25 million ft3 of natural gas was flared (NNPC). This is equivalent to losing about 12,967.952 × 1012 Btu of energy that would have been used to generate power or converted to other forms of energy. In 2015, the World Bank estimated that 140 billion cubic meters of natural gas produced with oil is flared annually, mostly in developing countries without gas processing infrastructures, or other means of utilizing the produced gas. It is widely known that flaring or even, venting of gas contributes significantly to greenhouse gas emissions, with negative impacts on the environment. Thus, alternative solutions to reduce or utilize the quantity of gas flared are crucial issues. Therefore, the need to study and provide detailed understanding of these alternative solutions to gas flaring is important. This paperoutlined the harmful effects of gas flaring and the different possible alternatives to gas flaring. The proposed alternative solutions are gas for secondary oil recovery, feedstock for petrochemical plants, domestic uses, LNG & CNG, as well as energy conservation by storing as gas hydrate for future use or other purposes. Gas hydrate is stable above the freezing point of water and sufficiently high pressure. It is relatively stable under its saturation temperature and pressure and also much denser than normal ice. This property of gas hydrate can be experimentally investigated and capitalized on, to effectively store natural gas as hydrate for energy conservation instead of flaring the gas wastefully. The alternative solutions will convincingly reduce and in the nearest future stop gas flaring globally.
文摘This work deals with the multi-faceted impact of gas flaring on a global scale and the different approach employed by researchers to measure gas flared and its resulting emissions. It gives an overview of methods employed by these researchers in the oil and gas industry, academia and governments in attempt to determine ways of measuring and reducing gas flaring and its emission drastically. This approach so far includes analytical studies, numerical studies, modeling, computer simulations, etc. the goal behind each study being to mitigate the effects of gas flaring. The outcome indicates that there is a seemingly absence of a single global method, emission factor and estimation procedure used in the oil and gas industry all over the world to determine the volume of gas flared and its emissions be it from complete or incomplete combustion, sweet or sulphur present hydrocarbons and this poses a continuous problem in determining the actual impact of gas flaring and its emissions on human and its role in environmental degradation both at a local and global level. An attempt has also being made to cover up-to-date trends in gas flaring and current developments in some of the most flared countries.
文摘This study investigated the effects of gaseous emissions from crude storage tank and gas flaring on air and rainwater quality in Bonny Industrial Island. Ambient air quality parameters, rainwater and weather parameters were collected at 60 m, 80 m, 100 m, 200 m and control plot for 4 weeks at the Bonny. Rainwater parameters were investigated using standard laboratory tests. Data analyses were done using Analysis of variance, pairwise t-test and Pearson’s correlation statistical tools. Results show that emission rates, volatile organic compound (VOC) noise and flare temperature decreased with increasing distance from flare points and crude oil storage tanks. Findings further revealed the emission rates varied significantly with distance away from the gas flaring point (F = 6.196;p = 0.004). The mean concentration of pollutants between gas flare site and crude oil storage tank showed that CO (0.02 ± 0.001 - 0.002 ±0.001), SPM (0.011 ± 0.001 - 0.01 ± 0.001), VOC (0.005 ± 0.001 - 0.01 ± 0.001) and NO<sub>2</sub> (0.04 ± 0.001 - 0.005 ± 0.000) had significant variations (p > 0.05) with CO, O<sub>3</sub> and NO<sub>2</sub> having higher concentrations at the gas flare site while SPM, and VOC were higher around the crude oil storage tank site. Wind turbulence was higher around the gas flaring point (4.93 TKE) than the crude oil storage tank (4.55 TKE). Similarly, there was significant variation in the sun radiation, precipitation, and wind speed caused by gas flaring (1582.25 w/m<sup>2</sup>, 436.25 mm, 0.53 m/s) and crude oil storage tank (1536.25 w/m<sup>2</sup>, 3.91.41 mm, 0.51 m/s). There were also significant variations in flared temperature (F = 22.144;p = 0.001);NO<sub>2</sub> (F = 8.250;p = 0.001), CO (F = 6.000;p = 0.004) and VOC (F = 5.574;p = 0.006) with distance from the gas flaring point. The variation in the rainwater parameters with distance from the gas flaring indicated significant variations in pH (F = 5.594;p = 0.006). The study showed that the concentration of VOC and particulates were high in the supposedly control area which is perceived to be safe for human habitation. Significant variations exist in emission rate (p = 0.015), flare temperature (p = 0.001), NO<sub>2</sub> (p = 0.003), VOC (p = 0.001), noise (p = 0.041), hydrogen carbonate (p = 0.037) and chromium (p = 0.032) between the gas flaring and crude oil storage tank. Regular monitoring is advocated to mitigate the harmful effects of the pollutants.
文摘This paper discusses the thermodynamic and environmental assessment of flared gases in an oil field. The oil field for the case study is located in the Niger Delta region of Nigeria. The data required for this report were obtained during a nine-year period (2008-2016), which revealed production volumes, flared volumes, operating temperatures and pressures, gas compositions, gas density, and flow rates. With the data and the aid of fundamental thermodynamic equations and MATLAB program codes, analysis was carried out on combustion to ascertain the amount of flue gases. Analyses revealed that a total of 1.99175 × 1011 standard cubic feet of gas was flared during the said period, generating anthropogenics estimated at 582,319,618.1825 m3 (≈1.046 Mt) of CO2, 1,077,510,054.31 m3 (≈2.0 Mt) of water vapour, 14,960,560.91 m3 of methane emitted and contaminated the atmosphere creating serious environmental concerns. Further analyses also showed that the approximate adiabatic flame temperature is about 1965°C for the field under investigation. Exergy analyses carried out also revealed that a total of 3.6099 × 1013 kJ (36.099 TJ) of exergy was available which would have translated to 1.0189 × 1010 kWh of electrical energy for the period under investigation. Conclusively, some measures that can be taken to prevent gas flaring are that every new project on oil and gas should incorporate technical details of gas gathering and utilization plan at the conceptual and design phases of projects for gas commercialization, establishment of more gas-to-power project for gas utilization. Also Carbon capture technology should be enhanced, although the best option is flaring out based on the astronomical amount of carbon (IV) oxide and other greenhouse gases depicted by the results. The entire work and results showed that gas flaring is undesired and pernicious because it has thermal, environmental and economic consequences.
文摘Oil spills and gas flaring are major environmental problems and pose major source of adverse health outcomes to communities hosting oil wells and natural gas. As oil is spilt and gas is flared;air, soil and water in affected communities are polluted. Due to this, members of these communities are exposed to higher health risks. One vulnerable group that is usually affected in this regard is pregnant women. This systematic review identified and reviewed past studies on oil pollution and different types of pregnancy outcomes within a twenty-year gap, which is between 1999 and 2019. The review also discussed the exposure pathways of oil pollution. From a literature search on scientific databases conducted in August 2019 for articles relating to the objectives of the review, data were extracted from articles which met the inclusion criteria and contents were systematically analyzed based on types of pregnancy outcomes. This review showed that oil spill and gas flaring may put pregnant women at high risk of hypertensive disorders of pregnancy, gestational diabetes mellitus, maternal depression, miscarriages via three pathways. This review may be of some use in making policy in this area.
文摘The threat to human, fauna and flora life posed by pollution due to gas flaring cannot be over-emphasized. Gas flared often resulted in some environmental degradation, one of such influence is soil pollution and poor crop yield. This study examined the effect of gas flaring on soil and cassava productivity in Ebedei, Ukwuani LGA, Delta State. For the purpose of data collection, five (5) experimental sites were systematically selected around the flare site in Ebedei and a control site at Obiaruku. Soil samples were collected at surface 0 - 10 cm and 10 - 20 cm at distance of 50 m, 100 m, 150 m, 200 m and 250 m apart respectively away from the bund wall of the flare. The data generated were analysed using multiple regression and paired t-test analyses. The study revealed that the soils found in Ebedei have high composition of sand and soil temperature and are acidic. The soil electrical conductivity, Phosphorous, Nitrogen, Potassium and Sodium were very low. More so, the yield of cassava increases with a corresponding increase in distances from flare site. The first hypothesis revealed that there is significant variation in soil nutrients as distance increases from gas flare sites. This is evident from F value of 234.99 which is greater than the critical table value of 4.39. Furthermore, as flare distance increases, so also the organic carbon, electrical conductivity and Nitrogen increase. The second hypothesis revealed that there is a significant difference in cassava yield at gas-flared area and the non-flared area which is evident at t (6.032) is greater than the critical table (1.895) at P 0.05. It is therefore recommended that Government and FEPA should enact environmental Policies and revisit and review existing environmental and oil drilling laws in Nigeria with a view of updating them to international and environmental friendly standards.
文摘The extent to which a country develops is anchored around its resources;and this is evidenced in how the revenue derived from natural resources (especially the oil and gas industries) has influenced national development strategies. This notwithstanding, the existence of natural resources does not always translate to development, as these often times lead to complacency and mismanagement;Nigeria may have suffered from this. This paper establishes the impact of gas production, utilization, and flaring on the estimated monetary value of the goods and services produced in Nigeria (GDP), using multiple linear regression analysis. The result shows that while gas utilization has a positive impact on the nation’s GDP, gas production and flaring are negatively associated with GDP. The paper concludes that for these to positively stimulate economic growth, there is need to invest more in infrastructure in the industry, and review the regulatory framework guiding operations of the oil and gas industry.
文摘Since the discovery of oil and gas in Nigeria in 1956, much gas has been flared because the operators pay little or no concern to its utilization, and as such, trillions of dollars have been lost. In this paper, a model is proposed using Time Series Regression Model (TSRM) and Time Series Neural Network (TSNN) to model the production, utilization and flaring of natural gas in Nigeria with the ultimate aim of observing the trend of each activity. The results show that TSNN has better predictive and forecasting capabilities compared to TSRN. It is also observed that the higher the hidden neurons, the lower the error generated by the TSNN.
文摘This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average mean precipitation data sourced from CHRS at the University of Arizona and carbon dioxide emissions data from NASA’s AIRS in Giovanni,spanning from July 2002 to November 2011.To carry out the analysis,ArcGIS 5.0 and SPSS 25,employing Inverse Distance Weighting(IDW),were employed to assess CO_(2) emissions and rainfall for both November and July during the period from 2002 to 2011.Over the course of this study,it was observed that CO_(2) emission exhibited an upward trend,increasing from 327.5226 parts per million(ppm)in July 2002 to 390.0077 ppm in November 2011.Simultaneously,the rainfall demonstrated an increase,rising from 56.66 millimeters to 390.78 millimeters for both July and November from 2002 to 2011.Noteworthy findings emerged from the correlation analysis conducted.Specifically,from July 2000 to 2011,there was a weak positive correlation(0.3858)observed between CO_(2) emissions and minimum rainfall,while a strong negative correlation(–0.7998)was identified for maximum rainfall values.In November,both minimum and maximum CO_(2) emissions displayed strong negative correlations with rainfall,with coefficients of–0.8255 and–0.7415,respectively.These findings hold significant implications for comprehending the environmental dynamics within the Niger Delta.Policymakers and stakeholders can leverage this knowledge to formulate targeted strategies aimed at mitigating CO_(2) emissions and addressing potential climate change-induced alterations in rainfall patterns.
文摘Here,we study the temperature structure of flaring and non-flaring coronal loops,using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Observatory.We use data for loops of an X2.1-class-flaring active region(AR 11283)during 22:10 UT until 23:00 UT,on 2011 September 6;and a non-flaring active region(AR 12194)during 08:00:00 UT until 09:00:00 UT on2014 October 26.By using the spatially synthesized Gaussian differential emission measure(DEM)forward-fitting method,we calculate the peak temperatures for each strip of the loops.We apply the Lomb–Scargle method to compute the oscillation periods for the temperature series of each strip.The periods of the temperature oscillations for the flaring loops ranged from 7 to 28.4 minutes.These temperature oscillations show very close behavior to the slow-mode oscillation.We observe that the temperature oscillations in the flaring loops started at least around10 minutes before the transverse oscillations and continue for a long time duration even after the transverse oscillations ended.The temperature amplitudes increased during the flaring time(20 minutes)in the flaring loops.The periods of the temperatures obtained for the non-flaring loops ranged from 8.5 to 30 minutes,but their significances are less(below 0.5)in comparison with the flaring ones(near to one).Hence the detected temperature periods for the non-flaring loops’strips are less probable in comparison with the flaring ones,and maybe they are just fluctuations.Based on our confined observations,it seems that the flaring loops’periods show more diversity and their temperatures have wider ranges of variation than the non-flaring ones.More accurate commentary in this respect requires more extensive statistical research and broader observations.
文摘We have studied the spectral behavior of theⅡPeg binary system in the ultraviolet band by using International Ultraviolet Explorer(IUE)observations over the period 1979-1993.The ultraviolet observations reveal indication of flare activity in both chromosphere and transition region with their enhanced emission lines.Before and after the flare activity the ultraviolet emission lines show low,intermediate and high flux.The spectral behavior is compared with previous studies.We detect prominent flare activity in 1989,1990 and 1992.Before and after this period there is a gradual clear decrease in the level of activity.The reddening ofⅡPeg was determined from a 2200?absorption feature to be E(B-V)=0.10±0.02.We ascertained the average mass loss rate to be≈1×10^(-8)M_(☉)yr^(-1),and an average ultraviolet luminosity to be≈6×10^(29)erg s^(-1).We attributed the spectral variations to a cyclic behavior of the underlying magnetic dynamo and the prominent activity can be interpreted by the model of a two-ribbon flare.
文摘During the lifetime of AR 12673,its magnetic field evolved drastically and produced numerous large flares.In this study,using full maps of the Sun observed by the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory,we identified that AR 12673 emerged in decayed AR 12665,which had survived for two solar rotations.Although both ARs emerged at the same location,they possessed different characteristics and different flare productivities.Therefore,it is important to study the long-term magnetic evolution of both ARs to identify the distinguishing characteristics of an AR that can produce large solar flares.We used the Space-weather Helioseismic and Magnetic Imager Active Region Patch data to investigate the evolution of the photospheric magnetic field and other physical properties of the recurring ARs during five Carrington rotations.All these investigated parameters dynamically evolved through a series of solar rotations.We compared the long-term evolution of AR 12665 and AR 12673 to understand the differences in their flare-producing properties.We also studied the relation of the long-term evolution of these ARs with the presence of active longitude.We found that the magnetic flux and complexity of AR12673 developed much faster than those of AR 12665.Our results confirmed that a strong emerging flux that emerged in the pre-existing AR near the active longitude created a very strong and complex AR that produced large flares.
基金supported by NIH/NIDCR grant R01DE025664 to IPC.
文摘Craniometaphyseal dysplasia(CMD),a rare craniotubular disorder,occurs in an autosomal dominant(AD)or autosomal recessive(AR)form.CMD is characterized by hyperostosis of craniofacial bones and metaphyseal flaring of long bones.Many patients with CMD suffer from neurological symptoms.The pathogenesis of CMD is not fully understood.
基金the National Natural Science Foundation of China (Grant Nos. 50909067, 51009102)the Program for New Century Excellent Talents in University (Grant No. 2011SCU-NCET-10-0589)
文摘The experimental studies of the flaring gate pier applied on the surface spillway in a high-arch dam show that a shock-wave will appear when the pattern of the flow is kept as super-critical. Meanwhile, the water depth at the outlet increases significantly, the flow moves downward in different directions, and the plunging jet is in a narrow and long shape, with a full longitudinal diffusion. In addition, the variation of the flaring gate pier design parameters affects little the discharge capacity of the surface spillway, these parameters including the contraction ratio fl, the contraction angle c~ and the spillway chute angle O. The pressure on the bottom of the spillway increases along the way and reaches the maximum before the outlet, and then decreases rapidly. Due to the flow impacting, the pressure on both sidewalls increases abruptly at the turning line of the flaring gate pier. To see the characteristics of the flow in the flaring gate pier, a simple calculation method is suggested based on the conversation of energy and mass, and the calculation methods for the jet trajectory and the horizontal length in air are also proposed. The results are found in good agreement with experimental data.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50479061).
文摘The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aerated cavity occured behind piers. The interaction of the weir head, the elevation difference between crest and chamber outlet, the first step height, the slopes of weir end and step, and the size of cavity, was investigated, the expression was derived to characterize their relationship, and the corresponding curves were plotted. The comparison of the calculated and simulated results with the measured data was performed. When the slopes of step and weir end are equivalent, the relative height difference between the first and second steps becomes the main factor influencing the aerated cavity. These findings may be useful in practical applications.
文摘A new-style flood discharging dam, which consolidates the flaring gate pier and the stepped spillway for discharging the flood through the dam surface, had been applied in China. The theoretical study on it is in a beginning stage at present. The three-dimensional numerical simulation has not been reported. In this paper, the 3D numerical calculation on the two-phase flow of water and air with discharge per unit width 195m~ 3 /s· m is presented . The results indicate that there is negative pressure on the juncture of the spillway surface and the first step. There forms obvious longitudinal and transverse eddies on the steps and the velocity decreases obviously compared with the smooth spillway. The figures of the velocity distributions and the water-air two-phase flows are plotted. The results calculated on the pressure are in agreement with the experimental data. Based on the position of the negative pressure obtained from calculation, measurement points of pressure are arranged in physical model. The experimental results validate the existence of the negative pressure. Being an applied and trial study, the results obtained are of theoretical and practical significance.
文摘Using the new soft X-ray data from the Macao Science Satellite-1,we studied a solar flare that occurred on 22 June 2023.We found that the centroids of the Ca(around 3.9 keV)and Fe(around 6.7 keV)line features exhibit a rapid shift toward higher energy channels during the flare's rising phase,followed by a gradual decrease during the decay phase.Through precise energy calibration,the centroids are determined with high accuracy.Temperature and velocity are then self-consistently derived by comparing the centroids with those calculated from the synthesized line features using the latest CHIANTI atomic database(ver.10.1).The calculated maximum velocity reaches up to 710±60 km s-1,which significantly exceeds the previously reported values.Our results suggest that the entire shift of soft X-ray lines may occur during the process of chromospheric evaporation.
基金supported by the National Natural Science Foundation of China(NSFC)under grant No.12233012,the Strategic Priority Research Program of the Chinese Academy of Sciences,grant No.XDB0560102the National Key R&D Program of China 2022YFF0503003(2022YFF0503000)。
文摘The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatial resolution than expected.In this paper,we developed the SDI point-spread function(PSF)and Image Bivariate Optimization Algorithm(SPIBOA)to improve the quality of SDI images.The bivariate optimization method smartly combines deep learning with optical system modeling.Despite the lack of information about the real image taken by SDI and the optical system function,this algorithm effectively estimates the PSF of the SDI imaging system directly from a large sample of observational data.We use the estimated PSF to conduct deconvolution correction to observed SDI images,and the resulting images show that the spatial resolution after correction has increased by a factor of more than three with respect to the observed ones.Meanwhile,our method also significantly reduces the inherent noise in the observed SDI images.The SPIBOA has now been successfully integrated into the routine SDI data processing,providing important support for the scientific studies based on the data.The development and application of SPIBOA also paves new ways to identify astronomical telescope systems and enhance observational image quality.Some essential factors and precautions in applying the SPIBOA method are also discussed.
基金supported by the National Key Basic R&D Program of China via 2023YFA1608303the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0550103)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(grant Nos.XDB0550000,XDB0550100 and XDB0550102)supported from the Strategic Pioneer Program of the Astronomy Large-Scale Scientific Facility,Chinese Academy of Sciences and the Science and Education Integration Funding of University of Chinese Academy of Sciencessupported by the National Natural Science Foundation of China(NSFCgrant Nos.12090040,12090041,12090041,12422303,12261141690,and 12403022)。
文摘This paper outlines the scientific goals and observational strategies of the Mini-SiTian Array.Mounted at Xinglong Observatory,the Mini-SiTian Array consists of three 30 cm telescopes and has been in operation since 2022.The large field of view,combined with the capability for multi-band photometric observations,enables the Mini-SiTian Array to perform rapid follow-up observations to identify optical counterparts of gravitational waves,capture the early light curves of tidal disruption events and supernovae,and monitor stellar flares,Be star outbursts,and cataclysmic variable stars,although its limiting magnitude is not very deep.By collaborating with the Xinglong2.16 m telescope and leveraging a real-time image processing pipeline,simultaneous photometric and spectroscopic observations could be performed to reveal their underlying physical mechanisms.The observational and research experience provides critical guidance for the implementation of the full-scale SiTian project in the future.
