Journal articles: 'Line emission study'

1

Hang, Hengrong, and Jianping Xia. "Recent study of emission line star 3G71." Chinese Science Bulletin 43, no. 6 (March 1998): 470–73. http://dx.doi.org/10.1007/bf02883811.

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Nepal, Sangeet, Parth Mahapatra, Sagar Adhikari, Sujan Shrestha, Prakash Sharma, Kundan Shrestha, Bidya Pradhan, and Siva Puppala. "A Comparative Study of Stack Emissions from Straight-Line and Zigzag Brick Kilns in Nepal." Atmosphere 10, no. 3 (March 1, 2019): 107. http://dx.doi.org/10.3390/atmos10030107.

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Nepal has approximately 1000 operational brick kilns, which contribute significantly to ambient air pollution. They also account for 1.81% of the total bricks produced in the South Asian region. Little is known about their emissions, which are consequently not represented in regional/global emission inventories. This study compared emissions from seven brick kilns. Four were Fixed Chimney Bull’s Trench Kilns (FCBTKs) and three were Induced-Draught Zigzag Kilns (IDZKs). The concentrations of carbon dioxide (CO2), sulfur dioxide (SO2), black carbon (BC), and particulate matter (PM) with a diameter less than 2.5 µm (PM2.5) were measured. The respective emission factors (EFs) were estimated using the carbon mass balance method. The average fuel-based EF for CO2, SO2, PM2.5, and BC were estimated as 1633 ± 134, 22 ± 22, 3.8 ± 2.6 and 0.6 ± 0.2 g per kg, respectively, for all FCBTKs. Those for IDZKs were 1981 ± 232, 24 ± 22, 3.1 ± 1, and 0.4 ± 0.2 g per kg, respectively. Overall, the study found that converting the technology from straight-line kilns to zigzag kilns can reduce PM2.5 emissions by ~20% and BC emissions by ~30%, based on emission factor estimates of per kilogram of fuel. While considering per kilogram of fired brick, emission reductions were approximately 40% for PM2.5 and 55% for BC, but this definitely depends on proper stacking and firing procedures.

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Ballereau, D., J. Chauville, A. Garcia, and J. Zorec. "Study of the HeI λ4471 line-profile of Be stars." Symposium - International Astronomical Union 162 (1994): 259–60. http://dx.doi.org/10.1017/s0074180900214988.

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In this paper we study the veiling effect and the strength of an extra emission-like component filling partially the HeI λ4471 line of Be stars. It is shown that this component is roughly correlated with the emission in the continuum and in the Hγ line.

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Amaro, Nuno, João Saragoça, Ricardo Cartaxo, Wei Yang, and Ren Yi. "IEEE 1901.1 Power Line Communication electromagnetic emission study." Journal of Physics: Conference Series 1983, no. 1 (July 1, 2021): 012059. http://dx.doi.org/10.1088/1742-6596/1983/1/012059.

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Alonso-Herrero, Almudena. "A Near-Infrared Study of Emission-Line Galaxies." Publications of the Astronomical Society of the Pacific 109 (January 1997): 69. http://dx.doi.org/10.1086/133860.

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Xiao, Hubing, Junhui Fan, Zhihao Ouyang, Liangjun Hu, Guohai Chen, Liping Fu, and Shaohua Zhang. "An Extensive Study of Blazar Broad Emission Line: Changing-look Blazars and the Baldwin Effect." Astrophysical Journal 936, no. 2 (September 1, 2022): 146. http://dx.doi.org/10.3847/1538-4357/ac887f.

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Abstract It is known that the blazar jet emissions are dominated by nonthermal radiation, while the accretion disk jets are normally dominated by thermal emission. In this work, our aim is to study the connection between the two types of emission by investigating the correlation between the blazar emission-line intensity property, which embodies the nature of an accretion disk, and the γ-ray flux property, which is the representative of jet emission. We compiled a sample of 656 blazars with available emission-line equivalent widths (EWs), the GeV γ-ray flux, and the spectral energy distribution (SED) information from the literature. In this work, we found 55 previous blazar candidates of uncertain types (BCUs) that are now identified as flat-spectrum radio quasars (FSRQs), and found 52 “changing-look” blazars based on their EWs, 45 of which are newly confirmed. These changing-look blazars have a larger accretion ratio ( M ̇ / M ̇ Edd ) than BL Lacertae (BL Lac) objects. In addition, we suggest that the lower synchrotron peak blazars (LSPs) could be the source of changing-look blazars because 90.7% of the changing-look blazars in this work are confirmed as LSPs. An anticorrelation between EW and continuum intensity, the so-called global “Baldwin effect” (BEff), has been confirmed. We suggest that the steeper global BEff observed for the blazar than for radio-quiet active galactic nuclei (RQ-AGNs) is caused by the inverse Compton scattering of broad-emission-line photons. This interpretation is further supported by the positive correlation between the emission-line EW and intrinsic inverse Compton luminosity.

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Zhang, Yan, and Chang Wang. "Study on the Relationship between the Energy Carbon Emission and Economic Growth in Hebei Province." Applied Mechanics and Materials 623 (August 2014): 310–16. http://dx.doi.org/10.4028/www.scientific.net/amm.623.310.

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This article simply reviewed the carbon emission situation in Hebei province from 1996 to 2011, and tried to use environmental Kuznets curve to analysis the impact of the economic growth of CO2 emissions on the energy consumption. The regression results show that CO2 emissions and economic growth in line with the environmental Kuznets curve inverted U-shaped, but it is in the left hemisphere of the curve, namely, as the growth of the economy, the CO2 emissions will continue to increase, so the carbon emission reduction work in Hebei province is still very heavy, we should change the energy consumption situation actively in the environment, adjust the industrial structure, develop new technology vigorously, and promote the innovation of emission reduction.

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Tomberlin, Kristen E., Richard Venditti, and Yuan Yao. "Life cycle carbon footprint analysis of pulp and paper grades in the United States using production-line-based data and integration." BioResources 15, no. 2 (April 7, 2020): 3899–914. http://dx.doi.org/10.15376/biores.15.2.3899-3914.

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Greenhouse gas (GHG) emission levels are causing concern as climate change risks are growing, emphasizing the importance of GHG research for better understanding of emission sources. Previous studies on GHG emissions for the pulp and paper industry have ranged in scope from global to regional to site-specific. This study addresses the present knowledge gap of how GHG emissions vary among paper grades in the US. A cradle-to-gate life cycle carbon analysis for 252 mills in the US was performed by integrating large datasets at the production line level. The results indicated that one metric ton of paper product created a production weighted average of 942 kg of carbon dioxide equivalent (kg CO2eq) of GHG emissions. Greenhouse gas emissions varied by pulp and paper grade, from 608 kg CO2eq per metric ton of product to 1978 kg CO2eq per metric ton of product. Overall, fuels were the greatest contributor to the GHG emissions and should be the focus of emission reduction strategies across pulp and paper grades.

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Fogel, Jeffrey, Orsola De Marco, and George Jacoby. "The Weak Emission Line Stars." Symposium - International Astronomical Union 209 (2003): 235–36. http://dx.doi.org/10.1017/s0074180900208589.

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In this paper, we study the evolution of the weak emission line central stars of planetary nebula (WELS), which are similar to the H-deficient Wolf-Rayet central stars except for systematically weaker emission lines. Our attempts at finding an evolutionary sequence for the WELS similar to what was established for Wolf-Rayet central stars, were unsuccessful. No correlation was found between any of the analysed quantities: emission and absorption line fluxes or stellar and nebular parameters from the literature. It does appear, however, that WELS have intermediate stellar temperatures (30–80 kK), and do not reside in the middle of Type I planetary nebulae, possibly indicating lower mass precursors.

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Xia, Lifang, Sangeeta Malhotra, James Rhoads, Norbert Pirzkal, Zhenya Zheng, Gerhardt Meurer, Amber Straughn, Norman Grogin, and David Floyd. "SPECTROSCOPIC STUDY OF THEHST/ACS PEARS EMISSION-LINE GALAXIES." Astronomical Journal 141, no. 2 (January 13, 2011): 64. http://dx.doi.org/10.1088/0004-6256/141/2/64.

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Bacalja, Bruna, Maja Krčum, and Merica Slišković. "A Line Ship Emissions while Manoeuvring and Hotelling—A Case Study of Port Split." Journal of Marine Science and Engineering 8, no. 11 (November 23, 2020): 953. http://dx.doi.org/10.3390/jmse8110953.

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Strategically, the Republic of Croatia, with its economy focused on tourism, is directly connected to the sea and coastal area, and integrated management of this area contributes to the sustainable development strategy. Worldwide, the problem of atmospheric pollution from maritime traffic is a poorly researched area, especially when this type of traffic is continuously growing. On the example of Port Split, the paper aims to present the following emission, carbon dioxide (CO2), nitrogen oxides (NOX), carbon monoxide (CO), volatile organic compounds (VOC), sulphur dioxide (SO2), particulate matter (PM) and black carbon, of line vessels during manoeuvring and hotelling phase for 2017, 2018 and 2019. Furthermore, the statistical analysis and appropriate conclusions have been performed on CO2 since all other emissions are linearly dependent. From the analyses in the hotelling and manoeuvring phase of line ships, it can be concluded that during 2019 there was a slight increase in emissions, but overall there was no significant increase in the number of line vessels and increased traffic. The obtained results of case study of port Split provide recommendations leading to further reduction of harmful gas emission, monitoring them, and integrating it into management of urban ports.

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Liu, Y. J., J. R. Fang, Y. W. Kang, L. Wang, and X. P. An. "Study on the assessment and reduction technology of carbon dioxide from cementing material manufacturing sector." Journal of Physics: Conference Series 2045, no. 1 (October 1, 2021): 012031. http://dx.doi.org/10.1088/1742-6596/2045/1/012031.

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Abstract For the purposes of simplifying the calculation task, adjusting production processes in time and solving the inconsistent requirements for carbon emissions, this paper investigates the calculation methods of carbon dioxide emissions from cement production, for example IPCC, WBCSD-CSI, MEE-CBMA, CNIS and BNU. Then a simplification and intuitive method is proposed. Based on the intuitive method, CO2 emission of 21 cement plants in China are calculated and analyzed, of which the error between the calculation results and those obtained by HJ 2519-2012 is less than 0.5%. About the carbon reduction technology in cement industry, there is limited reduction space that rely on energy efficiency improvements and clinker substitution. The technology of alternative fuels still needs to be further expanded. China has operated the first demonstration production line of CCUS technology at the Anhui Baimashan Conch cement plant with a capacity of 20,000 tons/year of industrial-grade liquid CO2 products and 30,000 tons/year of food-grade liquid CO2 products. Alternative raw material technology may be one developing direction to cut carbon emission; only 6.18% of steel slag was added to the raw meal at a 2500t/d production line, CO2 emission from process emissions were reduced by nearly 10%.

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Chhatkuli, D. N., S. Paudel, and B. Aryal. "A Detailed Morphological and Spectroscopic Study of Merging Dwarf Galaxy PGC 030133." Journal of Nepal Physical Society 7, no. 4 (December 31, 2021): 28–35. http://dx.doi.org/10.3126/jnphyssoc.v7i4.42928.

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We present a detailed morphology and spectroscopic study of a merging dwarf galaxy PGC 030133. Using the publicly available fiber spectroscopic data from the Sloan Digital Sky Survey (SDSS), we analyzed nine-strong emission lines of wavelength range 4336 Å to 6739 Å. We find that the strongest emission line is OIII5007, with an intensity of 146.32 × 10-17 erg/s/cm2 /Å. The observed emission lines are well fitted with a Gaussian profile with a coefficient of regression greater than 96%, and the derived full-width half maximum (FWHM) is less than 4.2Å. The Balmer decrement, characterized by the line ratio between Hα and Hβ is 3.07, suggesting a presence of dust at the center of PGC 030133. We derived the star-formation rate and emission line metallicity of PGC 030133 using extinction corrected emission line fluxes. SFR derived from Hα emission line flux is 0.0033 Mʘyear-1 and emission line metallicity derived from flux ratio between NII and Hα is 8.13 dex. Using the SDSS, g, and z-band imaging data, we derived morphological parameters. PGC 030133 has a half-light radius of 3.38 arc second and 3.05 arc second in g-band and z-band respectively and observed one-dimensional light profile is well fitted with a Sersic function with near exponential Sersic index ~ 0.9.

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Daelman, M. R. J., E. M. van Voorthuizen, L. G. J. M. van Dongen, E. I. P. Volcke, and M. C. M. van Loosdrecht. "Methane and nitrous oxide emissions from municipal wastewater treatment – results from a long-term study." Water Science and Technology 67, no. 10 (May 1, 2013): 2350–55. http://dx.doi.org/10.2166/wst.2013.109.

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Methane and nitrous oxide emissions from a fully covered municipal wastewater treatment plant were measured on-line during 16 months. At the plant under study, nitrous oxide contributed three-quarters to the plant's carbon footprint, while the methane emission was slightly larger than the indirect carbon dioxide emission related to the plant's electricity and natural gas consumption. This contrasted with two other wastewater treatment plants, where more than 80% of the carbon footprint came from the indirect carbon dioxide emission. The nitrous oxide emission exhibited a seasonal dynamic, of which the cause remains unclear. Three types of air filter were investigated with regard to their effectiveness to remove methane from the off-gas.

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Pradeep, Chaitanya Jasti. "Estimation of CO2 Emission Savings from a Metro Rail System Using Different Methodologies: A Case Study of Mumbai, India." European Transport/Trasporti Europei 81, ET.2021 (March 2021): 1–14. http://dx.doi.org/10.48295/et.2021.81.2.

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Estimating ‘CO2 emission savings’ of a mass rapid transit system (MRTS) project shall give an opportunity to earn carbon credits under clean development mechanism (CDM) of Kyoto protocol for ‘Non-Annex I’ countries like India. In this study, two methodologies for estimating ‘CO2 emission savings’ were demonstrated with a case study of Mumbai ‘metro line 1’. One considers actual reduction in vehicular traffic and the other considers the commuter shift to metro from other modes estimating the savings as 38.02 t/day and 27.63 t/day, respectively. Subsequently, sensitivity analysis was conducted to identify the optimal scenario for ‘CO2 emission savings’ supported by both the methods. Further, a breakeven scenario for ‘annual net CO2 emission savings’ after considering the indirect emissions due to electricity consumption by the metro system was also analysed as 1,008 t/year by the end 2019. These savings are analysed to further reach 32,537 t/year by 2025.

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Chun, M. S., E. C. Sung, H. K. Moon, and Y. I. Byun. "Spectroscopic Studies of Emission Line Galaxies." Symposium - International Astronomical Union 159 (1994): 442–43. http://dx.doi.org/10.1017/s0074180900176247.

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Spectroscopic Observations were made to study 42 emission line objects. The analysis of these long slit spectra shows that 15 out of 42 galaxies are blue compact galaxies (BCGs). 21 of them are starforming or HII galaxies and 3 were found to be normal galaxies.

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Bratus’, V., I. Indutnyi, P. Shepeliavyi, and T. Torchynska. "EPR and emission study of silicon suboxide nanopillars." MRS Proceedings 1617 (2013): 51–56. http://dx.doi.org/10.1557/opl.2013.1163.

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ABSTRACTThe results of correlated electron paramagnetic resonance (EPR) and photoluminescence (PL) study of obliquely deposited porous SiOxfilms after step-by-step 15 min annealing within 105 min in vacuum at 950°C are presented. The low intensity symmetrical and featureless EPR line with a g-value g=2.0044 and a linewidth of 0.77 mT has been detected in as-sputtered films and attributed to dangling bonds (DB) of silicon atoms in amorphous SiOxdomains withx=0.8. Successive annealing results in decreasing this line and the appearance of an intense EPR line with g=2.0025, linewidth of 0.11 mT and a hyperfine doublet with 1.6 mT splitting. According to the parameters this spectrum has been attributed to theEXcenter, a hole delocalized over four non-bridging oxygen atoms grouped around a Si vacancy in SiO2. The impact of chemical treatment before annealing and duration of anneals on the defect system, and a correlation of the PL intensity with decreasing of theDBEPR signal are discussed.

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Steele, A. W., and G. M. Hieftje. "A Detailed Study of Noise Sources in Selective Line Modulation Atomic Spectrometry." Applied Spectroscopy 40, no. 8 (November 1986): 1117–26. http://dx.doi.org/10.1366/0003702864507594.

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A detailed theoretical study is presented of the noise sources present in selective spectral line modulation (SLM) atomic emission spectrometry. Shot and flicker noise terms associated with the signal and background radiation, the modulating-reservoir transmission, the modulating-reservoir atom emission, the modulating-atom absorption, and the readout system are considered and compared. The results of the study reveal that shot noise never limits the precision of an SLM experiment. Instead, precision at high signal levels is limited by flicker noise associated with the modulating-atom reservoir transmission, the modulating-atom absorption, and the primary emission signal. In contrast, precision near the detection limit is limited by flicker noise associated with the modulating-atom emission and the background emission from the source and modulating-atom reservoir. The relative magnitudes of these noise sources were found to vary considerably with experimental conditions. Experimental data on four elements (Bi, Mg, Cu, Ag) are presented and compared. General trends of the noise magnitudes with experimental conditions are discussed and findings are extended to other elements that can be determined by the SLM method.

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Muratorio, G., and M. Friedjung. "Evidence for disks around certain luminous Magellanic cloud stars from the study of FeII." Symposium - International Astronomical Union 122 (1987): 443–44. http://dx.doi.org/10.1017/s0074180900156931.

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Study of FeII emission lines in emission and absorption using both emission line self absorption curves and ultraviolet spectral synthetis, shows that line emission is produced in the case of certain luminous Magellanic Cloud stars, in a region not in front of the photosphere. This region is most easily understood as being a disk. Absorption lines of FeII are either produced by a wind, or if the disk inclination is small with respect to the line of sight, in layers associated with the disk. The presence of disks also helps one to explain the form of the continuous energy distribution.

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Acker, Agnès, Sławomir K. Górny, and Björn Stenholm. "An extensive study of planetary nebulae with emission-line nuclei." Astrophysics and Space Science 238, no. 1 (April 1996): 63–66. http://dx.doi.org/10.1007/bf00645493.

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Jarad, M. M., R. W. Hilditch, and Ian Skillen. "A radial-velocity study of 18 emission-line B stars." Monthly Notices of the Royal Astronomical Society 238, no. 4 (June 1989): 1085–106. http://dx.doi.org/10.1093/mnras/238.4.1085.

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Sulaiman, Maisarah, Nor Azam Ramli, Wan Hashim Wan Ibrahim, Nur Baitul Izati Rasli, Mohd Rodzi Ismail, and Syabiha Shith. "Traffic Emissions due to Changes in Road Layout in Developing Township Related to Double Track Rail Project Constructions." Current World Environment 17, no. 3 (December 30, 2022): 557–75. http://dx.doi.org/10.12944/cwe.17.3.5.

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Traffic emissions in developing townships are less studied compared to major townships and cities. The Electrified Double-Track Project (EDTP) rail line is a linear project traversing from south to north of peninsular Malaysia. Construction of this line has somewhat affected the traffic flow in terms of delay and congestion, affecting traffic-related emissions. A study on the emission fluctuations due to traffic flow changes during the electrified double-track rail line construction was carried out in Parit Buntar, a developing township north of Peninsular Malaysia. Currently, not many primary study reports furnish insights into the effect of the project’s construction phase. Sidra 6.1 were used to estimate the traffic flow delay and level of service (LOS) at signalised intersections from traffic surveys of six intersections. These inputs were also used to estimate the fuel consumption and cost of fuel consumption for all three stages of emission contribution, namely before construction, during construction, and after construction (commissioning phase). The respective fuel consumption (L/hr.) before the construction, during construction, and post-construction were (437, 174, and 198) at J1, (-, 1650, and 264) at J2, (475, 2429, and 2384) at J3, (332, 336, and 261) at J4, and (206, 13996, and 452) at J5. This study found that a proper signal phasing post construction has improved delay time and traffic emission. The findings should be relevant for researchers interested in the emissions within the developing townships, especially in enhancing road layouts for the sustainability of life and well-being in the local and broader contexts.

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Zhang, Kerong, Liangyu Jiang, Yanzhi Jin, and Wuyi Liu. "The Carbon Emission Characteristics and Reduction Potential in Developing Areas: Case Study from Anhui Province, China." International Journal of Environmental Research and Public Health 19, no. 24 (December 7, 2022): 16424. http://dx.doi.org/10.3390/ijerph192416424.

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Global warming and world-wide climate change caused by increasing carbon emissions have attracted a widespread public attention, while anthropogenic activities account for most of these problems generated in the social economy. In order to comprehensively measure the levels of carbon emissions and carbon sinks in Anhui Province, the study adopted some specific carbon accounting methods to analyze and explore datasets from the following suggested five carbon emission sources of energy consumption, food consumption, cultivated land, ruminants and waste, and three carbon sink sources of forest, grassland and crops to compile the carbon emission inventory in Anhui Province. Based on the compiled carbon emission inventory, carbon emissions and carbon sink capacity were calculated from 2000 to 2019 in Anhui Province, China. Combined with ridge regression and scenario analysis, the STIRPAT model was used to evaluate and predict the regional carbon emission from 2020 to 2040 to explore the provincial low-carbon development pathways, and carbon emissions of various industrial sectors were systematically compared and analyzed. Results showed that carbon emissions increased rapidly from 2000 to 2019 and regional energy consumption was the primary source of carbon emissions in Anhui Province. There were significant differences found in the increasing carbon emissions among various industries. The consumption proportion of coal in the provincial energy consumption continued to decline, while the consumption of oil and electricity proceeded to increase. Furthermore, there were significant differences among different urban and rural energy structures, and the carbon emissions from waste incineration were increasing. Additionally, there is an inverted “U”-shape curve of correlation between carbon emission and economic development in line with the environmental Kuznets curve, whereas it indicated a “positive U”-shaped curve of correlation between carbon emission and urbanization rate. The local government should strengthen environmental governance, actively promote industrial transformation, and increase the proportion of clean energy in the energy production and consumption structures in Anhui Province. These also suggested a great potential of emission reduction with carbon sink in Anhui Province.

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Liu, Hongjiang, Fengying Yan, and Hua Tian. "A Vector Map of Carbon Emission Based on Point-Line-Area Carbon Emission Classified Allocation Method." Sustainability 12, no. 23 (December 2, 2020): 10058. http://dx.doi.org/10.3390/su122310058.

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An explicit spatial carbon emission map is of great significance for reducing carbon emissions through urban planning. Previous studies have proved that, at the city scale, the vector carbon emission maps can provide more accurate spatial carbon emission estimates than gridded maps. To draw a vector carbon emission map, the spatial allocation of greenhouse gas (GHG) inventory is crucial. However, the previous methods did not consider different carbon sources and their influencing factors. This study proposes a point-line-area (P-L-A) classified allocation method for drawing a vector carbon emission map. The method has been applied in Changxing, a representative small city in China. The results show that the carbon emission map can help identify the key carbon reduction regions. The emission map of Changxing shows that high-intensity areas are concentrated in four industrial towns (accounting for about 80%) and the central city. The results also reflect the different carbon emission intensity of detailed land-use types. By comparison with other research methods, the accuracy of this method was proved. The method establishes the relationship between the GHG inventory and the basic spatial objects to conduct a vector carbon emission map, which can better serve the government to formulate carbon reduction strategies and provide support for low-carbon planning.

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Chhatkuli, Daya Nidhi, Sanjaya Paudel, and Binil Aryal. "A spectroscopic study of the low redshift dwarf galaxy SDSS J134326.99+431118.7 to calculate star formation rate." BIBECHANA 18, no. 1 (January 1, 2021): 100–107. http://dx.doi.org/10.3126/bibechana.v18i1.29466.

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We present a spectroscopic study of an interacting emission-line dwarf galaxy SDSS J134326.99+431118.7. We analyzed eight-strong emission lines of wavelength in a range of 3902.1Å to 6619.1Å. Among them, the strongest emission line is OIII, with an intensity of 1043.6 x 10-17 erg/s/cm2/Å. These characteristic lines show a perfect Gaussian fit with a coefficient of regression greater than 98%, where the derived full width half maximum (FWHM) is less than 3.8 Å. The line ratio between Ha and Hb, (Ha/ Hb), is 2.73. This suggests that the galaxy is a starburst galaxy. Star Formation Rate (SFR) of the galaxy derived from Ha emission line flux is 0.019 and emission line metallicity derived from flux ratio between NII and Ha is 7.85 dex. These morphological and physical properties of SDSSJ134326.99+431118.7 are very similar to those of a typical Blue Compact Dwarf (BCD) galaxy. We conclude that we have presented another evidence of forming a BCD-type galaxy through a merger. BIBECHANA 18 (2021) 100-107

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Stirpe, Giovanna M., Andrew Robinson, and David J. Axon. "The Diversity of Broad Emission-Line Profiles." International Astronomical Union Colloquium 159 (1997): 197–98. http://dx.doi.org/10.1017/s0252921100040008.

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AbstractWe present preliminary results from a study of broad-line profiles in active galaxies. A simple model in which the emissivity is a broken power-law function of radius, and the BLR clouds emit anisotropically, yields very good fits to almost all the Ha profiles in our data base.

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Pauna, H., A. Tuomela, M. Aula, P. Turunen, V. Pankratov, M. Huttula, and T. Fabritius. "Toward On-Line Slag Composition Analysis: Optical Emissions from Laboratory Electric Arc." Metallurgical and Materials Transactions B 53, no. 1 (December 7, 2021): 454–65. http://dx.doi.org/10.1007/s11663-021-02382-5.

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AbstractElectric arc furnaces and ladle furnaces have an important role in the future of steelmaking where $$\hbox {CO}_2$$ CO 2 emissions have to be mitigated to an acceptable level. One way to address this goal is to optimize and improve the current practices by adjusting the chemistry and reactions with material additions or gas injections. These procedures would greatly benefit from on-line slag composition analysis. Since the electric arcs radiate throughout the melting, optical emission spectroscopy is a potential method for such analysis. In this study, optical emissions from the electric arc are measured in a laboratory environment. Dozens of atomic emission lines were correlated with $$\hbox {Cr}_2\hbox {O}_3$$ Cr 2 O 3 , $$\hbox {Fe}_2\hbox {O}_3$$ Fe 2 O 3 , $$\hbox {Al}_2\hbox {O}_3$$ Al 2 O 3 , $$\hbox {SiO}_2$$ SiO 2 , MnO, MgO, CaO, $$\hbox {CaF}_2$$ CaF 2 , $$\hbox {V}_2\hbox {O}_5$$ V 2 O 5 , and Ni content of the slag together with correlation between $$\hbox {CaF}_2$$ CaF 2 and molecular optical emission bands of CaF. Optimal spectral resolution for industrial applications was deducted to be between 0.022 and 0.179 nm.

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Zhang, Xujing, and Yan Chen. "Carbon Emission Evaluation Based on Multi-Objective Balance of Sewing Assembly Line in Apparel Industry." Energies 12, no. 14 (July 19, 2019): 2783. http://dx.doi.org/10.3390/en12142783.

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Apparel manufacturing is an industry with high energy consumption and carbon emissions. With the development of the low-carbon economy, low-carbon production in the apparel manufacturing industry become more and more imperative. The apparel industry is encountering great challenges in reducing carbon emissions. Garment sewing comprises a large number of processes, machines and operators. However, the existing studies lack quantitative analysis of carbon sources in the sewing process. This study analyzed the carbon emission characteristics in garment sewing production. Evaluation models of carbon emission were established for the sewing process in this research and the factors of fabrics, accessories, sewing machines and operators were included in the models. The results showed that fabrics and accessories were the main sources of carbon emissions in garment sewing production. The second largest carbon emission source was sewing machines, followed by operators. According to the evaluation models, the number of machines, operators and the utilization rate of the machines were related to the balance of the assembly line. A multi-objective optimization model aimed at minimizing the time loss rate and smoothness index of the assembly line was established, and a fast and elitist multi-objective genetic algorithm was used to obtain the solution for carbon emission reduction. The men’s shirt assembly lines, based on three types of workstation layouts (the order of processes, the type of machines and the components of the garment), were applied to verify the effectiveness of the model and algorithm. The results indicated that the total carbon emissions of the three assembly lines based on balance optimization were less than that of the normal assembly line. The assembly line of the workstations arranged in the order of processes was the best assembly line since it had the highest efficiency and the lowest carbon emissions.

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Saha, Shantanu, Yu-Chen Chang, Tilo Hongwei Yang, Anthony Rice, Arnob Ghosh, Weicheng You, Mary Crawford, Ting-Hua Lu, Yann-Wen Lan, and Shamsul Arafin. "Sub-bandgap photoluminescence properties of multilayer h-BN-on-sapphire." Nanotechnology 33, no. 21 (February 28, 2022): 215702. http://dx.doi.org/10.1088/1361-6528/ac5283.

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Abstract Two-dimensional hexagonal boron nitride (h-BN) materials have garnered increasing attention due to its ability of hosting intrinsic quantum point defects. This paper presents a photoluminescence (PL) mapping study related to sub-bandgap-level emission in bulk-like multilayer h-BN films. Spatial PL intensity distributions were carefully analyzed with 500 nm spatial resolution in terms of zero phonon line (ZPL) and phonon sideband (PSB) emission-peaks and their linewidths, thereby identifying the potential quantum point defects within the films. Two types of ZPL and PSB emissions were confirmed from the point defects located at the non-edge and edge of the films. Our statistical PL data from the non-edge- and edge-areas of the sample consistently reveal broad and narrow emissions, respectively. The measured optical properties of these defects and the associated ZPL peak shift and line broadening as a function of temperature between 77° and 300° K are qualitatively and quantitatively explained. Moreover, an enhancement of the photostable PL emission by at least a factor of ×3 is observed when our pristine h-BN was irradiated with a 532 nm laser.

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García Plaza, Eustaquio, Pedro Jose Núñez López, and A. R. Martin. "Evaluation of On-Line Signals for Roundness Monitoring." Advanced Materials Research 498 (April 2012): 85–90. http://dx.doi.org/10.4028/www.scientific.net/amr.498.85.

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The cutting forces, mechanical vibration and acoustic emission signals obtained using dynamometer, accelerometer, and acoustic emissions sensors have been extensively used to monitor several aspects of the cutting processes in automated machining operations. This study assesses the significance of these on-line signals for the real-time monitoring and diagnosis of the roundness error in automated cylindrical turning processes. The system developed is based on predictive models obtained by regression techniques employing the orthogonal components of the cutting forces, mechanical vibration and acoustic emissions, and combines all three types of sensors into one system. This monitoring system enables the on-line monitoring and diagnosis of roundness error by registering, visualizing, and characterizing the signals obtained during the machining process.

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Li, Teng, and Eryu Zhu. "Quantifying Carbon Emissions Generated by Monorail Transits: A Life Cycle Assessment Approach." Computational Intelligence and Neuroscience 2022 (March 24, 2022): 1–15. http://dx.doi.org/10.1155/2022/3872069.

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The use of rail transits results in the generation of a large amount of carbon emissions. Throughout the life cycle of a rail transit system, huge amounts of carbon are emitted, which contributes to the threat posed by carbon emission on the city ecosystem. Despite the many methods previously proposed to quantify carbon emissions from rail transit systems, a method that can be applied to measure carbon emissions of monorail systems is yet to be developed. We have used the life cycle assessment (LCA) method to propose a method that can be used to quantify carbon emissions from monorail transits. The life cycle of a monorail transit system was divided into four stages (production, construction, use, and end-of-life). A monorail transit line segment in Chongqing, China, was selected for a case study. The results show that the “use” stage of the monorail transit line system significantly increases (93.2%) carbon emissions, while the “end-of-life” stage does not contribute significantly to the total carbon emitted. The processes of generation of steal, concrete, and cement are the three leading processes that contribute to the emission of carbon dioxide. The percentages of carbon emitted during these processes are 32%, 29.6%, and 13.3%, respectively. Prestressed concrete activity accounts for the largest proportion (91.1%) of the total carbon emissions. The results presented herein can potentially help in realizing sustainable development and developing green transportation.

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KOO, BON-CHUL, JI-HYUN KANG, and N. M. MCCLURE-GRIFFITHS. "HI 21 CM EMISSION LINE STUDY OF SOUTHERN GALACTIC SUPERNOVA REMNANTS." Journal of The Korean Astronomical Society 37, no. 2 (June 1, 2004): 61–77. http://dx.doi.org/10.5303/jkas.2004.37.2.061.

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Hunter, Deidre A., and John S. Gallagher III. "An Emission‐Line Study of Supergiant Ionized Filaments in Irregular Galaxies." Astrophysical Journal 475, no. 1 (January 20, 1997): 65–82. http://dx.doi.org/10.1086/303520.

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Gallego Maestro, Jesus. "Study of a Complete Sample of H-alpha Emission-Line Galaxies." Publications of the Astronomical Society of the Pacific 107 (July 1995): 708. http://dx.doi.org/10.1086/133612.

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Kumar, P., H. Chand, R. Srianand, C. S. Stalin, P. Petitjean, and Gopal-Krishna. "Polarimetric and spectroscopic study of radio-quiet weak emission line quasars." Monthly Notices of the Royal Astronomical Society 479, no. 4 (July 9, 2018): 5075–82. http://dx.doi.org/10.1093/mnras/sty1802.

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Wright, D. J., P. L. Cottrell, A. E. Lynas-Gray, D. Kilkenny, and R. Shobbrook. "A Multi-Site Study of The Extreme Helium Star V2076 Oph." International Astronomical Union Colloquium 193 (2004): 539–42. http://dx.doi.org/10.1017/s0252921100011295.

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AbstractResults from a three-site photometric and spectroscopic campaign of the hottest known extreme helium star V2076 Oph are presented. V2076 Oph shows complex multiple periods ranging from 0.3 to 3 d. However for the two campaigns in 1982 and 2000, no definitive single period can be identified in both datasets. Some of the extracted periods appear to be one-day aliases of others. The two most convincing periods are 0.52 d (22.28 mHz) and 2.75 d (4.21 mHz). The spectral lines identified in V2076 Oph were He I, He II, C II (emission), C III (both emission and absorption), C IV and N III. These lines showed profile variations that could not be linked to the photometric variations. Individual line velocities vary by species and ionisation level. The spectral lines vary in phase with an amplitude of ~25 kms−1 – the exception is the strong C III emission line at 5696 Å which shows different behaviour and has the lowest observed average velocity. This indicates that this emission line originates in the stellar wind rather than the photosphere.

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Fursyak, M. I., and O. V. Kozlova. "A study of many-year spectral variability of the Ae Herbig star HD 36112." Acta Astrophysica Taurica 2, no. 1 (November 19, 2021): 21–25. http://dx.doi.org/10.31059/aat.vol2.iss1.pp21-25.

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We present the results of long-term high-dispersion spectral observations (R = 20000) of the Ae Herbig star HD 36112 in the regions of the Ha emission line and the NaI D resonance doublet lines. They show that parameters of the Ha emission line demonstrate complicated variability on several time scales: 1) variability from night to night caused by inhomogeneity of the circumstellar envelope; 2) variability on a time scale of about 1200d characterized by a variation of the equivalent width, intensity, and other emission parameters; 3) variability on a time scale of more than 4000d observed as a many-year trend in variations of parameters of the Ha emission line. We associate these results with variability of physical and kinematic conditions in the inner regions of the accretion disk and wind. The most probable mechanism of this variability is a process of planet formation in the circumstellar disk.

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Natalia, Frida Christin, Andewi Rokhmawati, and Yulia Efni. "Factors Influencing the Greenhouse Gas Emissions Disclosure at Manufacture Company in the Indonesia Stock Exchange." INTERNATIONAL JOURNAL OF ECONOMICS, BUSINESS AND APPLICATIONS 5, no. 2 (December 20, 2020): 1. http://dx.doi.org/10.31258/ijeba.5.2.1-14.

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This study aims to examine empirically the factors that influence greenhouse gas emission disclosure. Factors examined in this research are a type of industry, firm size, profitability, and leverage. In this study, the researcher adopted the checklist issued by the Carbon Disclosure Project (CDP) to measure the extensive disclosure of greenhouse gas emissions. To examine the factors, the researcher utilized multiple regression. The population of this study was all manufacturing companies listed on the Indonesian Stock Exchange in 2018. This research applied the purposive sampling method to obtain 131 listed manufacturing in 2018. The result implies that firm size has a positive and significant correlation with greenhouse gas emission disclosure. Meanwhile, type of industry, profitability, and leverage had no significant correlation with greenhouse gas emission disclosure. Manufacturing companies, especially greenhouse gas-intensive companies, must participate in protecting the environment and help reduce greenhouse gas emissions as stipulated in Presidential Regulation No. 61 of 2011 concerning the National Action Plan for Reducing Greenhouse Gas Emissions. In line with the concept of performance measurement of "Triple Bottom Line," the company does not only pay attention to profit (profit) and people (social), the company must also pay attention to the planet (environment). So the company can compete with other companies. The results highlighted that the much resources of the company, the better the company is conducting a greenhouse-gas-emission reduction strategy. It makes it easier for the company to do the disclosure of greenhouse gas emissions.

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Wei, Jing Zi, and Ran Zhang. "Study and Analysis of On-Line Detection and Fault Diagnosis System of Rolling Bearing." Applied Mechanics and Materials 443 (October 2013): 218–22. http://dx.doi.org/10.4028/www.scientific.net/amm.443.218.

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This paper first of all gives an introduction to the structure of rolling bearing, development stage of fault and the main fault types; then, it makes an analysis of the common detection methods and the technologies involved in rolling bearing fault; at last, based on the emphasis on the rolling bearing on-line detection and fault diagnosis system of acoustic emission technology, it elaborates the basic principles of acoustic emission, rolling bearing fault detection and diagnosis system experiment setting. Meanwhile, it introduces modern signal processing technology into acoustic emission information feature extraction and state recognition, such as wavelet analysis and wavelet packet analysis.

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Cid Fernandes, Roberto, Grażyna Stasińska, Natalia Vale Asari, Abílio Mateus, Marielli S. Schlickmann, and William Schoenell. "Emission-Line Taxonomy and the Nature of AGN-Looking Galaxies in the SDSS." Proceedings of the International Astronomical Union 5, S267 (August 2009): 65–72. http://dx.doi.org/10.1017/s1743921310005582.

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AbstractMassive spectroscopic surveys like the SDSS have revolutionized the way we study AGN and their relations to the galaxies they live in. A first step in any such study is to define samples of different types of AGN on the basis of emission-line ratios. This deceivingly simple step involves decisions on which classification scheme to use and data quality censorship. Galaxies with weak emission lines are often left aside or dealt with separetely because one cannot fully classify them onto the standard star-forming, Seyfert, or LINER categories. This contribution summarizes alternative classification schemes which include this very numerous population. We then study how star-formation histories and physical properties of the hosts vary from class to class, and present compelling evidence that the emission lines in the majority of LINER-like systems in the SDSS are not powered by black-hole accretion. The data are fully consistent with them being galaxies whose old stars provide all the ionizing power needed to explain their line ratios and luminosities. Such retired galaxies deserve a place in the emission-line taxonomy.

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Wasowski, Marek, Tomasz Sikorski, Grzegorz Wisniewski, Pawel Kostyla, Jaroslaw Szymanda, Marcin Habrych, Lukasz Gornicki, Jaroslaw Sokol, and Mariusz Jurczyk. "The Impact of Supply Voltage Waveform Distortion on Non-Intentional Emission in the Frequency Range 2–150 kHz: An Experimental Study with Power-Line Communication and Selected End-User Equipment." Energies 14, no. 3 (February 2, 2021): 777. http://dx.doi.org/10.3390/en14030777.

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Knowledge of the conducted emissions in the frequency range 2–150 kHz contains some gaps related to the impact of the harmonics in the supply voltage on the nature of these emissions. It can be noticed that the conducted emissions from non-sinusoidal power supplies have not been studied sufficiently, and that the impact of this distortion may be greater than the generally known results of emission tests carried out under standardized test conditions. This paper is aimed at investigating experimental cases of the influence of supply voltage waveform distortion on non-intentional emission in the range 2–150 kHz and the efficiency of power line communication based on selected PRIME (PoweRline Intelligent Metering Evolution) power line communication (PLC) technology. A series of experimental laboratory studies were investigated, representing the operation of the investigated PLC system with different types of end-user equipment (LED—Light Emitting Diode, CFL—Compact Fluorescent Lamp, induction motor with frequency converter) working under a distorted supply voltage condition obtained by the programmable power supply for different scenarios of the admissible harmonics contribution in the range 0–2 kHz. The scenarios included limits defined in standards EN 50160 and IEC 61000-4-13. The researchers used spectral analysis with a notation to emission limits, compatibility levels, and mains signalling, as well as statistics of the PLC communication. The obtained results provide important conclusions, which may be applied both in the development of the design of the appliances in question and the higher frequency emission testing methods.

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Gautam, S. P., A. Silwal, N. Lamichhane, A. K. Jha, and B. Aryal. "Study of star formation rate and metallicity of the low redshift (z < 0.02) dwarf galaxies." BIBECHANA 18, no. 2 (February 23, 2021): 43–49. http://dx.doi.org/10.3126/bibechana.v18i2.34067.

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In this paper, we have presented an analysis of emission lines from two dwarf galaxies. We analyzed the strongest emission lines of wavelength ranging from 4100 Å to 6700 Å. Among these emission lines, Hα and OIII have the highest intensities with 113.09×10-17 erg/s/cm2/Å and 142.12×10-17 erg/s/cm2/Å in the galaxies SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3, respectively. The Gaussian fit carried out in these emission lines showed the perfect fits with regression coefficient greater than 98 %, and full width half maximum (FWHM) of less than 4 Å. The line ratios calculated between Hα and Hβ for SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3 were 2.78 and 2.85, respectively, suggesting that the galaxies are starburst galaxies. The measurement of the Hα line from both galaxies was then used to assess the rate of star formation. The star formation rate of the galaxies SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3 was found to be 0.010 M☉year-1 and 0.016 M☉year-1, respectively, indicating a low rate of star formation, and the emission line metallicity was derived using the Hα and NII line, which were measured to be 8.23 dex and 8.70 dex, respectively. BIBECHANA 18 (2) (2021) 43-49

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Chhatkuli, Daya Nidhi, Sanjaya Paudel, and Binil Aryal. "Study of Star Formation Rate and Metallicity of an Interacting Dwarf Galaxy NGC 2604." Journal of Institute of Science and Technology 25, no. 2 (December 25, 2020): 55–60. http://dx.doi.org/10.3126/jist.v25i2.33736.

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We present a study of the Sloan Digital all Sky Survey Data Release 12 (SDSS DR12) optical spectra of an interacting dwarf galaxy NGC 2604 that has redshift 0.0069. Thirteen characteristic emission lines were identified in the wavelength range of 3885 Å to 6742 Å, the strongest line was due to Hα emission with a value of emission-line flux 1538.8 erg/s/cm2/Å. The other twelve emission lines were observed because of OI doublet, Hβ, Hγ, Hδ, OIII doublet, HeI, SII doublet and NII doublet transitions. Eleven characteristic lines agreed perfectly with the Gaussian distribution with greater than 99.9 % coefficient of regression. However, full-width half maximum (FWHM) was found to be less than 5 Å. No absorption metallic lines were observed in the spectra which indicates that the galaxy was either newly formed. The line metallicity of the galaxy was found to be 8.4 dex and the extinction coefficient was 0.2134. The star formation rate due to Hα emission after extinction correction was found to be 0.0927 Mʘ year -1 which is almost double of the value (0.057 Mʘ year -1) before correction.

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Bhattacharya, Debbijoy, Krishna Mohana A, Subir Bhattacharyya, Nilay Bhatt, and C. S. Stalin. "Multiwavelength study of different flaring and low-activity states of blazar 4C+21.35." Monthly Notices of the Royal Astronomical Society 500, no. 1 (September 26, 2020): 1127–38. http://dx.doi.org/10.1093/mnras/staa2958.

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ABSTRACT Blazars, a class of active galactic nuclei, emit over the entire accessible electromagnetic spectrum and modelling of their broad-band spectral energy distribution (SED) is the key to constrain the underlying emission mechanisms. Here we report the results on the one-zone leptonic emission modelling carried out on the blazar 4C+21.35 using multiwavelength data spanning over the period 2008–2018. Broad-band SED modelling using γ-ray data from Fermi-Large Area Telescope, X-ray data from Swift-XRT and AstroSat, and UV–optical data from Swift-UVOT, AstroSat, and Catalina Real-Time Transient Survey was carried out at seven different epochs, including three γ-ray flaring episodes and four quiescent periods (three long-term averaged ones and one during AstroSat observing period). Our SED modelling suggests that two compact emission regions originating at a different time outside the broad-line region and moving away from the core with variation primarily in the jet electron spectra can explain the emission from the high-, moderate-, and low-activity periods. The emissions from high- and first low-activity states are likely to have originated in the first region. The moderate- and second low-activity states are likely due to the second emission region with fresh particle acceleration/injection at a later time.

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Walsh, J. R., and R. E. S. Clegg. "Polarized Line Profiles in Planetary Nebulae." Symposium - International Astronomical Union 155 (1993): 231. http://dx.doi.org/10.1017/s0074180900170937.

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There is much direct and indirect evidence for the presence of dust in Planetary Nebulae (PN): variations in extinction across the face of the nebulae; IR emission with strong 25 and 60μm fluxes; broad near-IR emission lines of Silicate, SiC and PAH grains; optically thick lines, such as [C IV]1550Å, have lower strength on account of the increased path length due to dust scattering; a centro-symmetric pattern of polarization vectors in a few PN (Leroy et al., A&A, 160, 171, 1986). An observational programme has begun to study the polarization profiles of bright emission lines in PN arising from dust scattering within the nebulae. The first results are discussed.

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RAI, VIRENDRA N., JAGDISH P. SINGH, FANG Y. YUEH, and ROBERT L. COOK. "Study of optical emission from laser-produced plasma expanding across an external magnetic field." Laser and Particle Beams 21, no. 1 (January 2003): 65–71. http://dx.doi.org/10.1017/s0263034603211137.

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The laser-induced plasma obtained from the liquid target and expanding across a steady magnetic field has been studied using atomic emission spectroscopy. The line emission from the plasma was enhanced (>1.5 times) in the presence of a magnetic field, whereas background emission decreases. Enhancement in line intensity was found to be mainly a function of plasma beta (β). An increased rate of three-body recombination in plasma particles due to the cooling of the plasma during its expansion and an increase in effective plasma density as a result of its confinement seems to be the reason behind this enhancement.

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Espey, Brian R., David A. Turnshek, Lincoln Lee, Jacqueline Bergeron, Alec Boksenberg, George F. Hartig, Buell T. Jannuzi, et al. "The HST quasar absorption line key project. 9: an emission-line study of PG 2251+113." Astrophysical Journal 434 (October 1994): 484. http://dx.doi.org/10.1086/174749.

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Todt, Helga, Miriam Peña, Julia Zühlke, Lida Oskinova, Wolf-Rainer Hamann, and Götz Gräfener. "Weak emission line central stars of planetary nebulae." Proceedings of the International Astronomical Union 7, S283 (July 2011): 510–11. http://dx.doi.org/10.1017/s1743921312012173.

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AbstractTo understand the evolution and morphology of planetary nebulae, a detailed knowledge of their central stars is required. Central stars that exhibit emission lines in their spectra, indicating stellar mass-loss allow to study the evolution of planetary nebulae in action. Emission line central stars constitute about 10 % of all central stars. Half of them are practically hydrogen-free Wolf-Rayet type central stars of the carbon sequence, [WC], that show strong emission lines of carbon and oxygen in their spectra. In this contribution we address the weak emission-lines central stars (wels). These stars are poorly analyzed and their hydrogen content is mostly unknown. We obtained optical spectra, that include the important Balmer lines of hydrogen, for four weak emission line central stars. We present the results of our analysis, provide spectral classification and discuss possible explanations for their formation and evolution.

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Cid Fernandes, R., M. S. Carvalho, S. F. Sánchez, A. de Amorim, and D. Ruschel-Dutra. "Detection of supernova remnants in NGC 4030." Monthly Notices of the Royal Astronomical Society 502, no. 1 (January 11, 2021): 1386–400. http://dx.doi.org/10.1093/mnras/stab059.

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ABSTRACT MUSE-based emission-line maps of the spiral galaxy NGC 4030 reveal the existence of unresolved sources with forbidden line emission enhanced with respect to those seen in its own H ii regions. This study reports our efforts to detect and isolate these objects and identify their nature. Candidates are first detected as unresolved sources on an image of the second principal component of the H β, [O iii] 5007, H α, [N ii] 6584, [S ii] 6716, 6731 emission-line data cube, where they stand out clearly against both the dominant H ii region population and the widespread diffuse emission. The intrinsic emission is then extracted accounting for the highly inhomogeneous emission-line ‘background’ throughout the field of view. Collisional to recombination line ratios like [S ii]/H α, [N ii]/H α, and [O i]/H α tend to increase when the background emission is corrected for. We find that many (but not all) sources detected with the principal component analysis have properties compatible with supernova remnants (SNRs). Applying a combined [S ii]/H α and [N ii]/H α classification criterion leads to a list of 59 sources with SNR-like emission lines. Many of them exhibit conspicuous spectral signatures of SNRs around 7300 Å, and a stacking analysis shows that these features are also present, except weaker, in other cases. At nearly 30 Mpc, these are the most distant SNRs detected by optical means to date. We further report the serendipitous discovery of a luminous (MV ∼ −12.5), blue, and variable source, possibly associated with a supernova impostor.

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Li, Qing, Qi Yin Shi, Zhi Yu Jin, Fan Yang, and Bao Bing Liu. "Study on Self Judgment of Location Lave Speed of Acoustic Emission on Concrete Members." Applied Mechanics and Materials 578-579 (July 2014): 1118–24. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.1118.

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The wave speed of acoustic emission in the medium is uncertain, which is influenced by the source characteristics and the relative position between the acoustic emission source and the sensors. Due to this difference, the results of TDOA location method determination of wave speed in advance are very discrete. As to liner location ,the more farther the distance between two acoustic emission source sensor are, the more serious the discrete error are. Any of the two sensors, a location line can be obtained by setting the wave speed as a horizontal coordinate and the location as the vertical coordinate. The horizontal coordinate of location line of the different sensors is the real wave speed of acoustic emission events. This method has lower computational complexity, which can overcome the influence on acoustic emission location which wave speed setting error brings, having some practical value in Engineering.

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Journal articles on the topic 'Line emission study'

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