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1
Wu, Kun, Jiyao Xu, Xinan Yue, Chao Xiong, Wenbin Wang, Wei Yuan, Chi Wang, Yajun Zhu, and Ji Luo. "Equatorial plasma bubbles developing around sunrise observed by an all-sky imager and global navigation satellite system network during storm time." Annales Geophysicae 38, no. 1 (February 5, 2020): 163–77. http://dx.doi.org/10.5194/angeo-38-163-2020.
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Abstract. A large number of studies have shown that equatorial plasma bubbles (EPBs) occur mainly after sunset, and they usually drift eastward. However, in this paper, an unusual EPB event was simultaneously observed by an all-sky imager and the global navigation satellite system (GNSS) network in southern China, during the recovery phase of a geomagnetic storm that happened on 6–8 November 2015. Observations from both techniques show that the EPBs appeared near dawn. Interestingly, the observational results show that the EPBs continued to develop after sunrise, and they disappeared about 1 h after sunrise. The development stage of EPBs lasted for at least about 3 h. To our knowledge, this is the first time that the evolution of EPBs developing around sunrise was observed by an all-sky imager and the GNSS network. Our observation showed that the EPBs drifted westward, which was different from the usual eastward drifts of post-sunset EPBs. The simulation from the Thermosphere–Ionosphere–Electrodynamics General Circulation Model (TIE-GCM) suggest that the westward drift of EPBs should be related to the enhanced westward winds at storm time. Besides this, bifurcation and merging processes of EPBs were observed by the all-sky imager in the event. Associated with the development of EPBs, an increase in the peak height of the ionospheric F region was also observed near sunrise, and we suggest the enhanced upward vertical plasma drift during the geomagnetic storm plays a major role in triggering the EPBs near sunrise.
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Bhattacharyya, Archana. "Equatorial Plasma Bubbles: A Review." Atmosphere 13, no. 10 (October 8, 2022): 1637. http://dx.doi.org/10.3390/atmos13101637.
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The equatorial plasma bubble (EPB) phenomenon is an important component of space weather as the ionospheric irregularities that develop within EPBs can have major detrimental effects on the operation of satellite-based communication and navigation systems. Although the name suggests that EPBs occur in the equatorial ionosphere, the nature of the plasma instability that gives rise to EPBs is such that the bubbles may extend over a large part of the global ionosphere between geomagnetic latitudes of approximately ±15°. The scientific challenge continues to be to understand the day-to-day variability in the occurrence and characteristics of EPBs, such as their latitudinal extent and the development of irregularities within EPBs. In this paper, basic theoretical aspects of the plasma processes involved in the generation of EPBs, associated ionospheric irregularities, and observations of their characteristics using different techniques will be reviewed. Special focus will be given to observations of scintillations produced by the scattering of VHF and higher frequency radio waves while they propagate through ionospheric irregularities associated with EPBs, as these observations have revealed new information about the non-linear development of Rayleigh–Taylor instability in equatorial ionospheric plasma, which is the genesis of EPBs.
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Zhang, Xuehua, Leonard Ortolano, and Zhongmei Lü. "Agency Empowerment through the Administrative Litigation Law: Court Enforcement of Pollution Levies in Hubei Province." China Quarterly 202 (June 2010): 307–26. http://dx.doi.org/10.1017/s0305741010000251.
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AbstractThe existing literature on China's 1989 Administrative Litigation Law (ALL) has rarely discussed a minor provision that permits administrative agencies to enlist court assistance in enforcing administrative decisions. Focusing on court enforcement of pollution levies, this study examines how and why ALL has been employed so extensively by administrative agencies, environmental protection bureaus (EPBs) in this context. The study is based on interviews with judges, EPB officials and polluters involved in court actions as well as court statistical data from 1992 to 2005 for Hubei province. EPBs' heavy reliance on court enforcement for collecting pollution levies and fines resulted from incentives that encouraged the formation of mutually beneficial relationships between courts and EPBs in the 1990s. Court involvement has enhanced EPBs' enforcement powers, but the courts' engagement in enforcement has neither curtailed EPBs' arbitrary exercise of discretionary power nor induced polluters to reduce waste discharges.
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Tang, Long, Osei-Poku Louis, Wu Chen, and Mingli Chen. "A ROTI-Aided Equatorial Plasma Bubbles Detection Method." Remote Sensing 13, no. 21 (October 29, 2021): 4356. http://dx.doi.org/10.3390/rs13214356.
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In this study, we present a Rate of Total Electron Content Index (ROTI)-aided equatorial plasma bubbles (EPBs) detection method based on a Global Navigation Satellite System (GNSS) ionospheric Total Electron Content (TEC). This technique seeks the EPBs occurrence time according to the ROTI values and then extracts the detrended ionospheric TEC series, which include EPBs signals using a low-order, partial polynomial fitting strategy. The EPBs over the Hong Kong area during the year of 2014 were detected using this technique. The results show that the temporal distribution and occurrence of EPBs over the Hong Kong area are consistent with that of previous reports, and most of the TEC depletion error is smaller than 1.5 TECU (average is 0.63 TECU), suggesting that the detection method is feasible and highly accurate. Furthermore, this technique can extract the TEC depletion series more effectively, especially for those with a long duration, compared to previous method.
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Kim, Na Young, Chakrabhavi Dhananjaya Mohan, Arunachalam Chinnathambi, Sulaiman Ali Alharbi, Gautam Sethi, Kanchugarakoppal S. Rangappa, and Kwang Seok Ahn. "Euphorbiasteroid Abrogates EGFR and Wnt/β-Catenin Signaling in Non-Small-Cell Lung Cancer Cells to Impart Anticancer Activity." Molecules 27, no. 12 (June 14, 2022): 3824. http://dx.doi.org/10.3390/molecules27123824.
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EGFR and Wnt/β-catenin signaling pathways play a prominent role in tumor progression in various human cancers including non-small-cell lung carcinoma (NSCLC). Transactivation and crosstalk between the EGFR and Wnt/β-catenin pathways may contribute to the aggressiveness of cancers. Targeting these oncogenic pathways with small molecules is an attractive approach to counteract various types of cancers. In this study, we demonstrate the effect of euphorbiasteroid (EPBS) on the EGFR and Wnt/β-catenin pathways in NSCLC cells. EPBS induced preferential cytotoxicity toward A549 (wildtype EGFR-expressing) cells over PC-9 (mutant EGFR-expressing) cells. EPBS suppressed the expression of EGFR, Wnt3a, β-catenin, and FZD-1, and the reduction in β-catenin levels was found to be mediated through the activation of GSK-3β. EPBS reduced the phosphorylation of GSK-3βS9 with a parallel increase in β-TrCP and phosphorylation of GSK-3βY216. Lithium chloride treatment increased the phosphorylation of GSK-3βS9 and nuclear localization of β-catenin, whereas EPBS reverted these effects. Forced expression or depletion of EGFR in NSCLC cells increased or decreased the levels of Wnt3a, β-catenin, and FZD-1, respectively. Overall, EPBS abrogates EGFR and Wnt/β-catenin pathways to impart its anticancer activity in NSCLC cells.
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Blanch, Estefania, David Altadill, Jose Miguel Juan, Adriano Camps, José Barbosa, Guillermo González-Casado, Jaume Riba, Jaume Sanz, Gregori Vazquez, and Raúl Orús-Pérez. "Improved characterization and modeling of equatorial plasma depletions." Journal of Space Weather and Space Climate 8 (2018): A38. http://dx.doi.org/10.1051/swsc/2018026.
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This manuscript presents a method to identify the occurrence of Equatorial Plasma Bubbles (EPBs) with data gathered from receivers of Global Navigation Satellite System (GNSS). This method adapts a previously existing technique to detect Medium Scale Travelling Ionospheric Disturbances (MSTIDs), which focus on the 2nd time derivatives of total electron content estimated from GNSS signals (2DTEC). Results from this tool made possible to develop a comprehensive analysis of the characteristics of EPBs. Analyses of the probability of occurrence, effective time duration, depth of the depletion and total disturbance of the EPBs show their dependence on local time and season of the year at global scale within the latitude belt from 35°N to 35°S for the descending phase of solar cycle 23 and ascending phase of solar cycle 24, 2002–2014. These results made possible to build an EPBs model, bounded with the Solar Flux index, that simulates the probability of the number of EPBs and their characteristics expected for a representative day at given season and local time (LT). The model results provided insight into different important aspects: the maximum occurrence of bubbles take place near the equatorial anomaly crests, asymmetry between hemispheres and preferred longitudes with enhanced EPBs activity. Model output comparisons with independent observations confirmed its soundness.
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Khamdan, Siti Syukriah, Tajul Ariffin Musa, and Suhaila M. Buhari. "DETECTION OF EQUATORIAL PLASMA BUBBLES USING GPS IONOSPHERIC TOMOGRAPHY OVER PENINSULAR MALAYSIA." Journal of Information System and Technology Management 6, no. 24 (December 1, 2021): 152–60. http://dx.doi.org/10.35631/jistm.624016.
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This paper presents the detection of the equatorial plasma bubbles (EPB) using the Global Positioning System (GPS) ionospheric tomography method over Peninsular Malaysia. This paper aims to investigate the capability of the GPS ionospheric tomography method in detecting the variations of the EPB over the study area. In doing so, a previous case study during post-sunset 5th April 2011 has been selected as a reference for the detection of the EPBs over the study area. It has been observed that at least three structures of the EPBs have been captured based on the rate of change total electron content (TEC) index (ROTI) from 12 UT until 19 UT. Therefore, the three-dimensional ionospheric profiles have been reconstructed over Peninsular Malaysia using the tomography method during the study period in order to capture the signature of the EPBs. In this study, the detection of the EPBs using the tomography method is based on the rate of change of electron density (ROTNe). The results from three-dimensional ionospheric tomography show only two structures of EPBs are detected during the study period. It has been observed that the ROTNe depleted up to ~-12x109el/cm. Overall, the results in this study show that the GPS ionospheric tomography capable to be utilized in detecting the variations of EPBs in support of ionospheric studies and monitoring in the Malaysian region.
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Ma, Xin, Mengjie Wu, Peng Guo, and Jing Xu. "Airglow Observation and Statistical Analysis of Plasma Bubbles over China." Atmosphere 14, no. 2 (February 8, 2023): 341. http://dx.doi.org/10.3390/atmos14020341.
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Airglow observation is a very effective method to investigate plasma bubbles, and can obtain their horizontal structure. In this study, the image processing method was used to process airglow data, including image enhancement, azimuth correction, and image projection, and the clear image products of equatorial plasma bubbles (EPBs) were obtained. Based on the optical data of the airglow imager in Hainan, we investigated the main optical features of EPBs, and statistically analyzed the occurrence of EPBs from September 2014 to August 2015. The observation results show that EPB exhibits plume-shaped structures, usually tilting westward, and EPB extends to a long distance along the geomagnetic field lines. It is found that the west wall of EPB is relatively stable, while there are some bifurcations on the east wall of EPB, and the bifurcation of EPB becomes more pronounced with time. Moreover, the spatial scale of EPB gradually increases with time, which is about several hundred kilometers, and the drift velocity of EPB is in the range of 40–130 m/s (+/−20 m/s). The statistical results show that EPBs mainly occur in the months of September to November and February to April, with a higher occurrence rate. In terms of seasonal occurrence, EPBs tend to appear more frequently in spring and autumn, and the occurrence rate of EPBs is relatively low in winter and summer.
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Barros, Diego, Hisao Takahashi, Cristiano M. Wrasse, and Cosme Alexandre O. B. Figueiredo. "Characteristics of equatorial plasma bubbles observed by TEC map based on ground-based GNSS receivers over South America." Annales Geophysicae 36, no. 1 (January 23, 2018): 91–100. http://dx.doi.org/10.5194/angeo-36-91-2018.
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Abstract. A ground-based network of GNSS receivers has been used to monitor equatorial plasma bubbles (EPBs) by mapping the total electron content (TEC map). The large coverage of the TEC map allowed us to monitor several EPBs simultaneously and get characteristics of the dynamics, extension and longitudinal distributions of the EPBs from the onset time until their disappearance. These characteristics were obtained by using TEC map analysis and the keogram technique. TEC map databases analyzed were for the period between November 2012 and January 2016. The zonal drift velocities of the EPBs showed a clear latitudinal gradient varying from 123 m s−1 at the Equator to 65 m s−1 for 35∘ S latitude. Consequently, observed EPBs are inclined against the geomagnetic field lines. Both zonal drift velocity and the inclination of the EPBs were compared to the thermospheric neutral wind, which showed good agreement. Moreover, the large two-dimensional coverage of TEC maps allowed us to study periodic EPBs with a wide longitudinal distance. The averaged values observed for the inter-bubble distances also presented a clear latitudinal gradient varying from 920 km at the Equator to 640 km at 30∘ S. The latitudinal gradient in the inter-bubble distances seems to be related to the difference in the zonal drift velocity of the EPB from the Equator to middle latitudes and to the difference in the westward movement of the terminator. On several occasions, the distances reached more than 2000 km. Inter-bubble distances greater than 1000 km have not been reported in the literature. Keywords. Ionosphere (equatorial ionosphere; ionospheric irregularities) – meteorology and atmospheric dynamics (thermospheric dynamics)
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Park, J., H. Lühr, C. Stolle, M. Rother, K. W. Min, and I. Michaelis. "The characteristics of field-aligned currents associated with equatorial plasma bubbles as observed by the CHAMP satellite." Annales Geophysicae 27, no. 7 (July 7, 2009): 2685–97. http://dx.doi.org/10.5194/angeo-27-2685-2009.
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Abstract. Field-aligned currents (FACs) generate magnetic deflections perpendicular to the ambient Earth magnetic field. We investigate the characteristics of FACs associated with equatorial plasma bubbles (EPBs) as deduced from magnetic field measurements by the CHAMP satellite. Meridional magnetic deflections inside EPBs show a clear hemispheric anti-symmetry for events observed before 21:00 LT: inward in the Northern Hemisphere and outward in the Southern Hemisphere. When an eastward electric field is assumed the magnetic signature signifies a Poynting flux directed downward along the magnetic field lines. This means that FACs are driven by a high-altitude equatorial source. Such a scheme cannot be drawn as strictly from our observations after 22:00 LT, possibly because of a westward turning of the electric field inside EPBs and/or a decay of EPBs later at night. The perpendicular magnetic deflection is tilted by 40° from the magnetic meridional plane in westward direction, which implies that the depleted volume of EPBs, as well as the FAC structure, is tilted westward by 40° above the magnetic equator. The peak-to-peak amplitude of the FAC density is found to range typically between 0.1–0.5 μA/m2. The field-aligned sheet current density and the diamagnetic current strength show no correlation.
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Padma, Tatiparti, Swapna Raghunath, and Usha Kumari Chintalapati. "Equatorial Plasma Bubbles Identification with Single Frequency GNSS Receiver Data." F1000Research 12 (January 11, 2023): 44. http://dx.doi.org/10.12688/f1000research.127244.1.
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Ionosphere is the highest contributor of positional error in Global Navigation Satellite System (GNSS) owing to the trans-ionospheric signal delay, distortion and possible outage. Equatorial and Low latitudinal ionosphere experiences frequent perturbations in plasma density most of which is due to the presence of Equatorial Plasma Bubbles (EPBs). In order to improve positional and navigational precision of GNSS signals, EPBs must be identified and corrected. EPBs begin to manifest post-sunset and continue to thrive past midnight. This paper proposes a Rate of TEC Index (ROTI) based EPB identifier using single frequency GNSS receiver data. GNSS data has been collected from the archives of Scripps Orbit and Permanent Array Center (SOPAC). The raw data has been downloaded from the global continuous network station, IISC, located at Bangalore (13.0219°N, 77.5671°E) in Receiver Independent Exchange (RINEX) format. Analysis of EPB occurrence has been carried out for six consecutive years in the second half of the 24th solar cycle (2014-2019). The results show a clear surge in the number of EPBs identified in the course of equinoxes.
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Ma, Guanyi, Klemens Hocke, Jinghua Li, Qingtao Wan, Weijun Lu, and Weizheng Fu. "GNSS Ionosphere Sounding of Equatorial Plasma Bubbles." Atmosphere 10, no. 11 (November 2, 2019): 676. http://dx.doi.org/10.3390/atmos10110676.
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Ground- and space-based Global Navigation Satellite System (GNSS) receivers can provide three-dimensional (3D) information about the occurrence of equatorial plasma bubbles (EPBs). For this study, we selected March 2014 data (during solar maximum of cycle 24) for the analysis. The timing and the latitudinal dependence of the EPBs occurrence rate are derived by means of the rate of the total electron content (TEC) index (ROTI) data from GNSS receivers in China, whereas vertical profiles of the scintillation index S4 are provided by COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate). The GNSS receivers of the low Earth orbit satellites give information about the occurrence of amplitude scintillations in limb sounding geometry where the focus is on magnetic latitudes from 20° S to 20° N. The occurrence rates of the observed EPB-induced scintillations are generally smaller than those of the EPB-induced ROTI variations. The timing and the latitude dependence of the EPBs occurrence rate agree between the ground-based and spaceborne GNSS data. We find that EPBs occur at 19:00 LT and they are mainly situated above the F2 peak layer which descended from 450 km at 20:00 LT to 300 km at 24:00 LT in the equatorial ionosphere. At the same time, the spaceborne GNSS data also show, for the first time, a high occurrence rate of post-sunset scintillations at 100 km altitude, indicating the coexistence of equatorial sporadic E with EPBs.
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Wiens, R. H., B. M. Ledvina, P. M. Kintner, M. Afewerki, and Z. Mulugheta. "Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed." Annales Geophysicae 24, no. 5 (July 3, 2006): 1443–53. http://dx.doi.org/10.5194/angeo-24-1443-2006.
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Abstract. An all-sky imager was installed in Asmara, Eritrea (15.4° N, 38.9° E, 7° N dip) and used to monitor the OI 630-nm nightglow. Nine months of data were studied between September 2001 and May 2002, a time including the recent maximum in the solar activity cycle. Equatorial plasma bubbles (EPBs) were recorded on 63% of nights with adequate viewing conditions. The station location within view of the equatorial ionization anomaly and with a magnetic declination near zero makes it an excellent test case for comparison with satellite studies of the seasonal variation of EPBs with longitude. The imager was accompanied by two Cornell GPS scintillation monitors, and the amplitude scintillation data are compared to the all-sky data. GPS scintillations indicate the beginning of EPBs, but die out sooner in the post-midnight period than the larger scale EPBs. Both phenomena exhibit clear occurrence maxima around the equinoxes. Ionospheric zonal drift speeds have been deduced from EPB and GPS scintillation pattern movement. Average near-midnight EPB drift speeds are between 100 and 120 m/s most months, with the GPS scintillation speeds being about the same. A winter drift speed maximum is evident in both EPB and GPS scintillation monthly means.
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Alotaibi, Saqer S., Hadeer Darwish, Madiha Zaynab, Sarah Alharthi, Akram Alghamdi, Amal Al-Barty, Mohd Asif, Rania H. Wahdan, Alaa Baazeem, and Ahmed Noureldeen. "Isolation, Identification, and Biocontrol Potential of Entomopathogenic Nematodes and Associated Bacteria against Virachola livia (Lepidoptera: Lycaenidae) and Ectomyelois ceratoniae (Lepidoptera: Pyralidae)." Biology 11, no. 2 (February 11, 2022): 295. http://dx.doi.org/10.3390/biology11020295.
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Virachola livia (Lepidoptera: Lycaenidae) and Ectomyelois ceratoniae (Lepidoptera: Pyralidae) are the key pests of pomegranates in Saudi Arabia that are managed mainly using broad-spectrum pesticides. Interactions between the entomopathogenic nematodes (EPNs) Steinernematids, and Heterorhabditids, and their entomopathogenic bacterial symbionts (EPBs) have long been considered monoxenic 2-partner associations responsible for killing insects and, therefore, are widely used in insect pest biocontrol. However, there are limited reports identifying such organisms in Taif, Saudi Arabia. The current study aimed to identify the EPNs and their associated bacteria isolated from Taif, Saudi Arabia, and evaluate their biocontrol potential on third instar larvae of V. livia and E. ceratoniae under laboratory conditions. A total of 35 EPN isolates belonging to Steinernema (20) and Heterorhabditis (15) were recovered from 320 soil samples. Twenty-six isolates of symbiotic or associated bacteria were isolated from EPNs and molecularly identified as Xenorhabdus (6 isolates), Photorhabdus (4 isolates), Pseudomonas (7), or Stenotrophomonas (9). A pathogenicity assay revealed that Steinernema spp. were more virulent than Heterorhabditis spp. against the two pomegranate insects, with LC50 values of 18.5 and 13.6 infective juveniles (IJs)/larva of V. livia for Steinernema spp. and 52 and 32.4 IJs/larva of V. livia for Heterorhabditis spp. at 48 and 72 h post-treatment, respectively. Moreover, LC50 values of 9 and 6.6 IJs/larva (Steinernema spp.) and 34.4 and 26.6 IJs/larva (Heterorhabditis spp.) were recorded for E. ceratoniae larvae at 48 and 72 h post-treatment. In addition, the EPB Stenotrophomonas maltophilia CQ1, isolated from Steinernema spp., surpassed Pseudomonas mosselii SJ10, associated with Heterorhabditis spp., in their ability to kill V. livia or E. ceratoniae larvae within 6 h post-application, resulting in 100% mortality in both insects after 24 and 48 h of exposure. We conclude that either application of EPNs’ IJs or their associated EPBs could serve as potential biocontrol agents for V. livia and E. ceratoniae.
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Kil, Hyosub. "The Occurrence Climatology of Equatorial Plasma Bubbles: A Review." Journal of Astronomy and Space Sciences 39, no. 2 (June 2022): 23–33. http://dx.doi.org/10.5140/jass.2022.39.2.23.
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Electron density irregularities in the equatorial ionosphere at night are understood in terms of plasma bubbles, which are produced by the transport of low-density plasma from the bottomside of the F region to the topside. Equatorial plasma bubbles (EPBs) have been detected by various techniques on the ground and from space. One of the distinguishing characteristics of EPBs identified from long-term observations is the systematic seasonal and longitudinal variation of the EPB activity. Several hypotheses have been developed to explain the systematic EPB behavior, and now we have good knowledge about the key factors that determine the behavior. However, gaps in our understanding of the EPB climatology still remain primarily because we do not yet have the capability to observe seed perturbations and their growth simultaneously and globally. This paper reviews the occurrence climatology of EPBs identified from observations and the current understanding of its driving mechanisms.
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Llanque Chayña, Edwin. "MODELACION HIDROLÓGICA CON PRECIPITACIONES OBTENIDAS POR SATÉLITE EN LA CUENCA DEL RÍO RAMIS PERÚ." Revista de Investigaciones 11, no. 4 (December 30, 2022): 214–26. http://dx.doi.org/10.26788/ri.v11i4.3918.
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En los últimos años, muchos investigadores han orientado sus estudios a aprovechar los beneficios que se pueden obtener a través de las Estimaciones de Precipitación Basadas en Satélite (EPB), en escalas de tiempo diarias, mensuales y anuales. El uso de EPBs es una de las alternativas para solucionar el problema de las cuencas con poco o ningún instrumento. El objetivo de la investigación es evaluar estimaciones de precipitación basadas en satélites, utilizando modelación hidrológica en la cuenca del río Ramis, Perú. La evaluación se llevó a cabo durante 16 años (2003 - 2019), utilizando EPBs, Tropical Rainfall Measurement Mission (TRMM-3B42) y Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks- Climate Data Record (PERSIANN-CDR). Los resultados de la comparación con estaciones meteorológicas indican que PERSIANN-CDR es mejor que TRMM-3B42 con r = 0,50 y 0,38 respectivamente. Sin embargo, el uso de las EPBS como datos de entrada en el modelo hidrológico, Herramienta de Evaluación de Suelos y Aguas (SWAT), los resultados obtenidos calibrados para TRMM-3B42 son insatisfactorios, con r = 0,77, NSE = -0,24 y el porcentaje de sesgo PBIAS = 56,50 %, para PERSIANN-CDR con r = 0,63, NSE = -0,01 y PBIAS = 62,30 %. Obteniendo un buen resultado r = 0,86 y NSE = 0,73 al utilizar las medidas de las estaciones meteorológicas. La evaluación de los datos de entrada en el modelo hidrológico muestra la magnitud del error de los EPBs, cuyos datos de entrada deben ser corregidos antes de ser utilizados
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Wang, Gui He, and Yu You Yang. "Study on Soil Improvement Technology of EPBS Tunnel." Advanced Materials Research 378-379 (October 2011): 484–88. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.484.
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The tunnel construction often encounters the problem of adaptability of sand-gravel formation and earth pressure balance shield (EPBS) construction, which has brought new technical problems and challenges to those who are participating in the construction project. In order to ensure the normal operation of shield construction, the soil must have ideal plasticity and liquidity, and low permeability to intercept groundwater. Therefore, we must adopt the soil improvement techniques ,namely, to inject the modified materials (mud, foam, polymer, etc.) into excavation face and earth pressure tank(if necessary, to the screw conveyor) to ensure the stability of excavation face, achieve EPBS driving, and help to reduce mechanical load, reduce land subsidence, and increase driving speed at the same time. The ground improvement technique is an important part of the EPBS method. The quality of the application of soil improvement technology is very important to maintain the stability of excavation face and the screw dump device’s dumping smoothly. It also has a significant impact on the shield machine’s functioning safely,economically and efficiently.
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Paznukhov, V. V., C. S. Carrano, P. H. Doherty, K. M. Groves, R. G. Caton, C. E. Valladares, G. K. Seemala, et al. "Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum." Annales Geophysicae 30, no. 4 (April 16, 2012): 675–82. http://dx.doi.org/10.5194/angeo-30-675-2012.
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Abstract. We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements. Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985, 2010a). While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.
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Park, J., H. Lühr, C. Stolle, M. Rother, K. W. Min, and I. Michaelis. "Field-aligned current associated with low-latitude plasma blobs as observed by the CHAMP satellite." Annales Geophysicae 28, no. 3 (March 2, 2010): 697–703. http://dx.doi.org/10.5194/angeo-28-697-2010.
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Abstract. Here we give two examples of low-latitude plasma blobs accompanied by linearly polarized perpendicular magnetic deflections which imply that associated field-aligned currents (FACs) have a 2-D sheet structure located at the blob walls. The estimated FAC density is of the order of 0.1 μA/m2. The direction of magnetic deflections points westward of the magnetic meridian and there is a linear correlation between perpendicular and parallel variations. All these properties are similar to those of equatorial plasma bubbles (EPBs). According to CHAMP observations from August 2000 to July 2004, blobs show except for these two good examples no clear signatures of 2-D FAC sheets at the walls. Generally, perpendicular magnetic deflections inside blobs are weaker than inside EPBs on average. Our results are consistent with existing theories: if a blob exists, (1) a significant part of EPB FAC will be closed through it, exhibiting similar perpendicular magnetic deflection inside EPBs and blobs, (2) the FAC closure through blobs leads to smaller perpendicular magnetic deflection at its poleward/downward side, and (3) superposition of different FAC elements might result in a complex magnetic signature around blobs.
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Huang, Xue Gang, Yu You Yang, and Gui He Wang. "Three-Dimensional Face Stability Analysis of EPBS Tunnels." Advanced Materials Research 378-379 (October 2011): 449–52. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.449.
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A three-dimensional (3D) failure mechanism, based on the framework of the kinematical approach of limit analysis theory, is applied to calculate the face supporting pressure of a circular tunnel driven by the Earth Pressure Balance Shield (EPBS). The geometry of the mechanisms considered is composed of a sequence of truncated rigid cones. The numerical results obtained are presented.
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Wei, Yingjie, Duli Wang, Jianguang Li, and Yuxin Jie. "Effects of Soil Conditioning on Characteristics of a Clay-Sand-Gravel Mixed Soil Based on Laboratory Test." Applied Sciences 10, no. 9 (May 9, 2020): 3300. http://dx.doi.org/10.3390/app10093300.
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Soil conditioning is of great significance for tunneling in soft ground with earth pressure balance shield (EPBS) machines, which leads to safe, highly efficient, and high-quality tunneling. To study the effects of soil conditioning on properties of a clay-sand-gravel mixed soil encountered in an EPBS tunneling project in Beijing, a series of geotechnical test methods was carried out based on laboratory test in this paper. The decay behaviors of foam particles generated by the Waring-Blender method were studied first using the image particle analysis system, and then the feasibility of soil conditioning on the mixed soil was qualitatively and quantitatively assessed through the mixing test, slump test, and friction coefficient test. The preliminary test results indicate that drainage of water in liquid film plays an important role in the decay of foam microstructure. The viscosity and flowability of the conditioned soil were modified dramatically by using various amount of water and foam, and a suitable state meeting the requirement of EPBS machines was obtained. The net power and mixing time, which reflects the interaction between the blending rods and tested soils, as well as the slump value, providing the overall indication for liquidity of the conditioned soils, and friction coefficient, reflecting the friction between steel and tested soils, were used to provide insight into the variation in viscosity and flowability of the tested soils.
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Joshi, Lalit Mohan, Lung-Chih Tsai, Shin-Yi Su, and Abhijit Dey. "Variability of Equatorial Ionospheric Bubbles over Planetary Scale: Assessment of Terrestrial Drivers." Atmosphere 13, no. 9 (September 17, 2022): 1517. http://dx.doi.org/10.3390/atmos13091517.
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Nighttime F-region field-aligned irregularities (FAIs) associated with equatorial plasma bubbles (EPBs) are impacted by terrestrial factors, such as solar irradiance and geomagnetic activity. This paper examines the impact of the planetary-scale periodic variability of terrestrial processes on EPB activity. Continual observations of the Equatorial Atmosphere Radar (EAR) have been utilized to derive the intra-seasonal variability of nighttime F-region FAIs in the context of the terrestrial factors mentioned above. A periodicity analysis using wavelet and Lomb–Scargle (LS) spectral analysis indicated significant amplitudes of the long-period planetary-scale variability in the F-region FAI signal-to-noise ratio (SNR), 10.7 cm flux, and geomagnetic indices, as well as a shorter period of variability. Interestingly, a careful inspection of the time series indicated the planetary-scale variability of F-region FAIs to be reasonably out of phase with the periodic geomagnetic variability. EPB occurrence and the FAI signal-to-noise ratio presented a systematic decrease with an increase in the level of geomagnetic activity. Non-transient quiet-time geomagnetic activity has been found to suppress both the occurrence as well as the strength of F-region FAIs. The impacts of planetary-scale geomagnetic activity appear to be non-identical in the summer and equinoctial EPBs. The results highlight the importance of periodic terrestrial processes in driving the planetary-scale variability of EPBs.
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Park, J., H. Lühr, and M. Noja. "Three-dimensional morphology of equatorial plasma bubbles deduced from measurements onboard CHAMP." Annales Geophysicae 33, no. 1 (January 28, 2015): 129–35. http://dx.doi.org/10.5194/angeo-33-129-2015.
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Abstract. Total electron content (TEC) between Low-Earth-Orbit (LEO) satellites and the Global Navigation Satellite System (GNSS) satellites can be used to constrain the three-dimensional morphology of equatorial plasma bubbles (EPBs). In this study we investigate TEC measured onboard the Challenging Minisatellite Payload (CHAMP) from 2001 to 2005. We only use TEC data obtained when CHAMP passed through EPBs: that is, when in situ plasma density measurements at CHAMP altitude also show EPB signatures. The observed TEC gradient along the CHAMP track is strongest when the corresponding GNSS satellite is located equatorward and westward of CHAMP with elevation angles of about 40–60°. These elevation and azimuth angles are in agreement with the angles expected from the morphology of the plasma depletion shell proposed by Kil et al.(2009).
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Xiong, C., H. Lühr, S. Y. Ma, C. Stolle, and B. G. Fejer. "Features of highly structured equatorial plasma irregularities deduced from CHAMP observations." Annales Geophysicae 30, no. 8 (August 24, 2012): 1259–69. http://dx.doi.org/10.5194/angeo-30-1259-2012.
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Abstract. In this study five years of CHAMP (Challenging Mini-satellite Payload) fluxgate magnetometer (FGM) data is used to investigate the characteristics of Equatorial Plasma Bubbles (EPBs). We filtered the FGM data by using band-passes with four different cut-off periods to get the EPBs with different maximum spatial scale sizes in the meridional plane ranging from 76–608 km. Associated with the EPB observations at about 400 km, the typical altitude of CHAMP during the year 2000–2005, we also investigate the post-sunset equatorial vertical plasma drift data from ROCSAT-1 (Republic of China Satellite 1). Since the height of the F-layer is highly correlated with the vertical plasma drift and solar flux, we sorted the ROCSAT-1 data into different groups by F10.7. From the integrated vertical drift we have estimated the post-sunset uplift of the ionosphere. By comparing the properties of EPB occurrence for different scale sizes with the global distribution of plasma vertical uplift, we have found that EPBs reaching higher altitudes are more structured than those which are sampled by CHAMP near the top side of the depleted fluxtube. Such a result is in accord with 3-D model simulations (Aveiro and Hysell, 2010). Small-scale EPB structures are observed by CHAMP when the irregularities reach apex heights of 800 km and more. Such events are encountered primarily in the Brazilian sector during the months around November, when the post-sunset vertical plasma drift is high.
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Chapagain, Narayan P. "Electrodynamics of the Low-latitude Thermosphere by Comparison of Zonal Neutral Winds and Equatorial Plasma Bubble Velocity." Journal of Institute of Science and Technology 20, no. 2 (November 26, 2015): 84–89. http://dx.doi.org/10.3126/jist.v20i2.13955.
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The coincident observations of nighttime thermospheric zonal neutral winds and equatorial plasma bubble (EPB) drift velocities over Brazil during the October–December,2009 and 2010 are used to examine the coupling relationship between the thermosphere and ionosphere. The EPB zonal drift velocities are estimated using the airglow images recorded by optical imaging system, while the neutral winds are measured by using a bi-static Fabry–Perot interferometer (FPI) experiment deployed at two stations from Brazil. The results reveal the similar pattern in the EPB drift velocities and zonal neutral winds motion during the nighttime and night-to-night thereby illustrating a fully developed F-region dynamo. However, background natural winds also exceed EPBs velocities especially during the development phase of EPBs illustrating that F-region dynamo is not fully activated.Journal of Institute of Science and Technology, 2015, 20(2): 84-89
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Lin, Xin, Xiong Zhou, and Yuyou Yang. "A New Soil Conditioner for Highly Permeable Sandy Gravel Stratum in EPBs." Applied Sciences 11, no. 5 (February 27, 2021): 2109. http://dx.doi.org/10.3390/app11052109.
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Full-face water-rich gravel stratum is a large challenge during tunnel excavation with earth pressure balance shields (EPBs) because of accidents such as water spewing from the screw conveyor and ground collapse. Slurry and polymer have been used as conditioning agents to avoid such problems and thus ensure a successful tunneling. However, limited improvement of sandy gravel was achieved when traditional soil conditioner were applied. This study proposes a new conditioner (modified slurry) consisting of bentonite slurry, viscosity modifier, sodium silicate and polymer, which will enhance the properties of sand gravel stratum. Low reaction time, high apparent viscosity, good plastic behavior and low permeability were employed for investigating the optimum ratio of the ingredients. The proposed modified slurry has a good performance in conditioning sandy gravel soils and can be the reference for EPBs’ excavation in highly permeable, non-adhesive coarse-grained soil stratum.
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Xiong, C., J. Park, H. Lühr, C. Stolle, and S. Y. Ma. "Comparing plasma bubble occurrence rates at CHAMP and GRACE altitudes during high and low solar activity." Annales Geophysicae 28, no. 9 (September 6, 2010): 1647–58. http://dx.doi.org/10.5194/angeo-28-1647-2010.
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Abstract. Based on the multi-year data base (2001–2009) of CHAMP Planar Langmuir Probe (PLP) data and GRACE K-Band Ranging (KBR1B) data, typical features of ionospheric plasma irregularities are studied at the altitudes of CHAMP (300–400 km) and GRACE (~500 km). The phenomena we are focusing on are the equatorial plasma bubbles (EPBs). Similar seasonal/longitudinal (S/L) distributions of EPB have been found at both CHAMP and GRACE altitudes during solar active and quiet years. Peak EPB occurrence rates, defined as number of events within an S/L bin divided by the number of passes over that bin, decrease from the high and moderate solar flux period (2001–2005) to the low solar flux period (2005–2009) from 80% to 60% and 60% to 40% at CHAMP and GRACE altitudes, respectively. On average the occurrence rate increases linearly with solar flux at about the same rate at CHAMP and GRACE. For high flux levels (P10.7>200) non-linear increases are observed at GRACE. The occurrence rate increases rapidly after 19:00 local time (LT) during high solar flux periods. Around solar minimum rates increase more gently and peak around 22:00 LT. The highest occurrence rates are encountered at latitudes around 10° north and south of the dip equator. Results from the two altitudes support the notion that EPBs form regions of depleted plasma along geomagnetic fluxtubes. It is shown for the first time that in regions of high occurrence rates EPBs are associated with fluxtubes reaching greater apex heights than those in regions of low rates.
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Burke, W. J., C. Y. Huang, and R. D. Sharma. "Stormtime dynamics of the global thermosphere and equatorial ionosphere." Annales Geophysicae 27, no. 5 (May 5, 2009): 2035–44. http://dx.doi.org/10.5194/angeo-27-2035-2009.
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Abstract. During magnetic storms the development of equatorial plasma bubbles (EPBs) and distributions of thermospheric densities are strongly influenced by the histories of imposed magnetospheric electric (εM) fields. Periods of intense EPB activity driven by penetration εM fields in the main phase are followed by their worldwide absence during recovery. A new method is applied to estimate global thermospheric energy (Eth) budgets from orbit-averaged densities measured by accelerometers on polar-orbiting satellites. During the main phase of storms Eth increases as long as the stormtime εM operates, then exponentially decays toward quiet-time values during early recovery. Some fraction of the energy deposited at high magnetic latitudes during the main phase propagates into the subauroral ionosphere-thermosphere where it affects chemical and azimuthal-wind dynamics well into recovery. We suggest a scenario wherein fossils of main phase activity inhibit full restoration of quiet-time dayside dynamos and pre-reversal enhancements of upward plasma drifts near dusk denying bottomside irregularities sufficient time to grow into EPBs.
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Kherani, Esfhan A., and Eurico R. de Paula. "Observations of Quasi-Periodic Electric Field Disturbances in the E Region before and during the Equatorial Plasma Bubble." Atmosphere 12, no. 9 (August 27, 2021): 1106. http://dx.doi.org/10.3390/atmos12091106.
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Wave-like electric field disturbances in the ionosphere before the Equatorial Plasma Bubble (EPB) are the subject of numerous recent studies that address the issue of possible short-term forecasting of EPB. We report the observations of the Equatorial Quasi-Periodic-Electric field Disturbances (QP-EDs) of the Field-aligned Irregularities (FAI) in the E region before the EPB occurrence in the F region. They are observed from 30 MHz coherent scatter radar during the SpreadFEx campaign 2005 carried out in Brasil. The presently reported QP-EDs at the equatorial E region below an altitude of 110 km are undescribed so far. Though QP-EDs characteristics vary on a day-to-day basis, consistent features are their intensification before the EPB, and their simultaneous occurrence with EPBs. This study highlights the monitoring of QP-EDs in the short-term forecasting of EPBs and further reveals the robust energetics of vertical coupling between E and F regions.
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Chapagain, Narayan P. "Dynamics Ionospheric Plasma Bubbles Measured by Optical Imaging System." Journal of Institute of Science and Technology 20, no. 1 (November 25, 2015): 20–27. http://dx.doi.org/10.3126/jist.v20i1.13906.
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Deep plasma depletions during the nighttime period in the equatorial ionosphere (referred to as equatorial plasma bubbles –EPBs) can significantly affect communications and navigation systems. In this study, we present the image measurements of plasma bubble from Christmas Island (2.1°N, 157.4°W, dip latitude 2.8°N) in the central Pacific Ocean. These observations were made during September-October 1995 using a Utah State University (USU) CCD imaging system measured at ~280 km altitude. Well-defined magnetic field-aligned plasma depletions were observed for 18 nights, including strong post-midnight fossilized structures, enabling detailed measurements of their morphology and dynamics. We also estimate zonal velocity of the plasma bubbles from available images. The zonal drift velocity of the EPBs is a very important parameter for the understanding and modeling of the electrodynamics of the equatorial ionosphere and for the predictions of ionospheric irregularities. The eastward zonal drift velocities were around 90-100 m/s prior to local midnight, and decreases during the post-midnight period that persisted until dawn.Journal of Institute of Science and Technology, 2015, 20(1): 20-27
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Lim, Meng Hee, and M. S. Leong. "Reconstruction of Vital Blade Signal from Unsteady Casing Vibration." Advances in Mechanical Engineering 6 (January 1, 2014): 146983. http://dx.doi.org/10.1155/2014/146983.
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Some important information pertaining to blade fault is thought to be concealed in highly unsteady casing vibration. This paper explores suitable methods to best reconstruct blade related signals from raw casing vibration, which could be used for diagnosis of blade fault. The feasibility of translation invariant wavelet transform and cycle spinning (TIWT-CS) technique in reconstruction of these signals is investigated in this paper. Subsequently, a new parameter for blade fault diagnosis, namely, the energy profile of blade signal (EPBS), is formulated. Experimental results show that TIWT-CS method effectively retained blade related signals, while other unwanted signals such as system noises and aerodynamic induced vibration are reasonably suppressed. EPBS provides an indication of the condition of blade faults in rotor system, whereby the exact position and the quantity of faulty blades, as well as the root cause of blade fault, can be identified. In comparison, the energy profile plots using unfiltered casing vibration were found to be highly unstable and therefore provides inconsistent results for diagnosis of blade fault.
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Nyongesa, Edward, Ndinya Boniface, and Omondi George. "Occurrence characteristics of equatorial plasma bubbles over Kisumu, Kenya during Solar maximum of Solar Cycle 24." International Journal of Advanced Astronomy 9, no. 1 (January 13, 2021): 1. http://dx.doi.org/10.14419/ijaa.v9i1.31262.
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Equatorial Plasma Bubbles (EPBs) are irregular plasma density depletions in the ambient electron density in the equatorial F-region ionosphere generated after sunset. EPBs are known to bring disruptions to telecommunication and navigation systems. This paper investigates the occurrence of EPBs over Kisumu, Kenya (Geomagnetic coordinates: 9.64o S, 108.59o E; Geographic coordinates: 0.02o S, 34.6o E) for a few selected quiet and storm days between 1st January 2013 and 31st December 2014 which was a high Solar activity period for Solar Cycle 24. The study brings out EPB occurrence pattern over Kisumu, Kenya for the selected quiet and storm days of 2013 and 2014. The Receiver Independent Exchange (RINEX) data was retrieved from the Kisumu high data-rate NovAtel GSV4004B SCINDA-GPS receiver. The data was unzipped and processed to obtain Vertical Total Electron Content (VTEC), amplitude scintillation (S4) and Universal Time (UT) which were then fed into MATLAB to generate VTEC and S4 plots against UT for each selected quiet and storm day within the years 2013 and 2014. The Total Electron Content (TEC) depletion depths and S4 index values between 16:00 and 20:00 UT for each selected quiet and storm day were extracted from the VTEC and S4 plots and used to plot TEC depletion depths and S4 plots. The Rate of Change of TEC (ROT) and Rate of Change of TEC Index (ROTI) between 16:00 and 20:00 UT were generated from VTEC and used to plot ROT and the corresponding ROTI plots against UT. TEC depletion depths and ROTI values for each selected quiet and storm day between 16:00 and 20:00 UT were extracted and used to plot TEC depletion depths and ROTI plots and S4 index and ROTI plots. In this study, the enhancement of S4 index corresponded well with TEC depletions, increased fluctuation of ROT and higher ROTI values between 16:00UT and 20:00UT for most days. This correspondence was used in inferring the occurrence of EPBs during the selected quiet and storm days of the years 2013 and 2014. The obtained results showed that the highest EPB occurrence was during March equinox with 33.33% occurrence in the year 2013 and 30.76% occurrence in the year 2014, followed by the September equinox which had 20.38% occurrence in 2013 and 17.26% occurrence in 2014. The seasonal variation of EPB occurrence was attributed to the variation in the daytime E x B drift velocities. Larger E x B drift velocities resulted in increased EPB occurrence in the equinoctial period (March, April, August and September) and November solstice period (November and December) while lower E x B drift velocities resulted in reduced EPB occurrence in the June solstice period (June and July). The percentage EPB occurrence in the year 2013 was 6.49% while in the year 2014 was 4.32%. The storm period had percentage EPB occurrence of 21.42% in the year 2013 and 21.88% in the year 2014 while the quiet period had percentage EPB occurrence of 18.75% in the year 2013 and 7.89% in the year 2014. These results clearly showed that the percentage EPB occurrence was higher during the storm period than in the quiet period. Hence the development of EPBs was enhanced by geomagnetic activity through several competing dynamics such as Prompt Penetration Electric Field (PPEF), Disturbance Dynamo Electric Field (DDEF) and reduction in electron density due to increased recombination rates.
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Viardot, Eric. "Branding in B2B: the value of consumer goods brands in industrial markets." Journal of Business & Industrial Marketing 32, no. 3 (April 3, 2017): 337–46. http://dx.doi.org/10.1108/jbim-11-2014-0225.
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Purpose This paper aims to explore whether consumer goods brands (CGBs) have more brand equity than exclusively professional brands (EPBs) do in the context of the industrial detergents market. Design/methodology/approach The author conducted direct customer interviews at the outlets of two large wholesale distribution retail chains. The sample included 211 respondents. Findings The study shows that CGBs do have brand equity in business-to-business (B2B) market. First, they enjoy a greater top-of-mind awareness than do EPBs. Second, they have a distinctive brand image, as they are perceived as being more efficient and more expensive than are EPBs. Research limitations/implications There are three main limitations. First, the results may reflect industry-specific factors that are not representative of all professional markets. Second, the products studied are relatively low in price compared to other categories of professional products. Third, the sample market is a mature market characterized by a modest growth rate and limited development in related markets. However, these limitations do not discredit the results of the study. Conversely, they invite further research on the subject of CGBs extending into professional markets. Future research could examine other product categories as well as the use of an experimental approach to validate and generalize the primary results. Practical implications This research has implications for business-to-consumer marketing professionals looking to leverage the equity of their CGBs in the B2B space. In addition, this work can help B2B marketing professionals better defend their market share in the face of well-known CGB entering their market. Originality/value This study represents an exploratory analysis, as the author has not any found prior work on this topic. In addition to these original results, the paper contributes to a better understanding of the concept of brand equity in B2B for academics and provides new insights for industrial marketers regarding branding in B2B.
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Gentile, L. C., W. J. Burke, and F. J. Rich. "A global climatology for equatorial plasma bubbles in the topside ionosphere." Annales Geophysicae 24, no. 1 (March 7, 2006): 163–72. http://dx.doi.org/10.5194/angeo-24-163-2006.
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Abstract. We have developed a global climatology of equatorial plasma bubble (EPB) occurrence based on evening sector plasma density measurements from polar-orbiting Defense Meteorological Satellite Program (DMSP) spacecraft during 1989-2004. EPBs are irregular plasma density depletions in the post-sunset ionosphere that degrade communication and navigation signals. More than 14400 EPBs were identified in ~134000 DMSP orbits. DMSP observations basically agree with Tsunoda's (1985) hypothesis that EPB rates peak when the terminator is aligned with the Earth's magnetic field, but there are also unpredicted offsets in many longitude sectors. We present an updated climatology for the full database from 1989-2004 along with new plots for specific phases of the solar cycle: maximum 1989-1992 and 1999-2002, minimum 1994-1997, and transition years 1993, 1998, and 2003. As expected, there are significant differences between the climatologies for solar maximum and minimum and between the two solar maximum phases as well. We also compare DMSP F12, F14, F15, and F16 observations at slightly different local times during 2000-2004 to examine local time effects on EPB rates. The global climatologies developed using the DMSP EPB database provide an environmental context for the long-range prediction tools under development for the Communication/Navigation Outage Forecasting System (C/NOFS) mission.
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Li, Qiang, Yanbo Zhu, Kun Fang, and Jisi Fang. "Statistical Study of the Seasonal Variations in TEC Depletion and the ROTI during 2013–2019 over Hong Kong." Sensors 20, no. 21 (October 30, 2020): 6200. http://dx.doi.org/10.3390/s20216200.
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Equatorial plasma bubbles (EPBs) can cause large total electron content (TEC) gradient magnitudes and significant density irregularities. In this paper, depletions and irregularities due to EPBs are identified by using the Global Positioning System (GPS)-TEC time series extracted from nine Global Navigation Satellite System (GNSS) stations over Hong Kong near the equatorial ionization anomaly (EIA) crest region from 2013 to 2019. The correlation analyses between the daily variation in the rate of TEC change index (ROTI) and that of the EPB occurrence rate, depth, and duration are presented. The monthly EPB occurrence rate, depth, duration, and ROTI show strong seasonal variations, with maxima during equinoctial seasons, especially during the moderate-to-high solar activity years of 2013–2016. Furthermore, two seasonal asymmetries can be clearly seen for these parameters from 2013 to 2016. The EPB occurrences rate, depth, and duration vary annually with the solar radio flux at 10.7 cm (F10.7) index. The correlation analyses of the EPB occurrence rate, depth, and duration are found to be much more strongly correlated with the F10.7 index on an annual basis than on a monthly basis. The correlation analysis of monthly variations shows the impacts of solar activity on EPB occurrence, depth, and duration are seasonally dependent, which is significantly greater in the equinoctial seasons and summer than in winter.
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Tilt, Bryan. "The Political Ecology of Pollution Enforcement in China: A Case from Sichuan's Rural Industrial Sector." China Quarterly 192 (December 2007): 915–32. http://dx.doi.org/10.1017/s0305741007002093.
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AbstractThis article uses a case study approach to examine the processes and consequences of pollution enforcement in an industrial township in rural Sichuan. China's national pollution emissions standards are relatively strict, but enforcement is the responsibility of some 2,500 Environmental Protection Bureaus (EPBs) within municipal and county governments. EPB officials exercise considerable discretion in prioritizing and carrying out enforcement activities, but exactly what factors influence regulatory behaviour within EPBs is poorly understood. Data for the article are drawn from interviews with EBP officials, township government officials, industrial managers and local residents, as well as a review of township and district financial records and pollution enforcement records. In this case study, EPB enforcement priorities and actions were guided by State Council directives and State Environmental Protection Administration policy, but citizen complaints and media exposure regarding polluting factories also played a key role, and action culminated in the forced closure of township factories. The article uses political ecology as an analytical framework for understanding how pollution enforcement is shaped by the competing values, goals and priorities within the EPB and the administrative unit in which it operates. This is crucial in China, where the decentralized nature of environmental oversight requires an examination of both policy formulation and implementation. The implications of pollution enforcement on rural enterprises for ecological health, fiscal revenue and rural development are also discussed.
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Sarudin, I., N. S. A. Hamid, M. Abdullah, and S. M. Buhari. "Investigation of zonal velocity of equatorial plasma bubbles (EPBs) by using GPS data." Journal of Physics: Conference Series 852 (May 2017): 012014. http://dx.doi.org/10.1088/1742-6596/852/1/012014.
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Martinelli, Daniele, C. Todaro, A. Luciani, and D. Peila. "Use of a large triaxial cell for testing conditioned soil for EPBS tunnelling." Tunnelling and Underground Space Technology 94 (December 2019): 103126. http://dx.doi.org/10.1016/j.tust.2019.103126.
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Moeinossadat, Sayed Rahim, Kaveh Ahangari, and Kourosh Shahriar. "Control of Ground Settlements Caused by EPBS Tunneling Using an Intelligent Predictive Model." Indian Geotechnical Journal 48, no. 3 (July 19, 2017): 420–29. http://dx.doi.org/10.1007/s40098-017-0253-7.
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Yu, Jun, Jingfan Zheng, Dongkai Li, Zhen He, and Zhizhong Zhang. "Analytical study on the seepage field of EPBS and preliminary discrimination of spewing." Tunnelling and Underground Space Technology 140 (October 2023): 105241. http://dx.doi.org/10.1016/j.tust.2023.105241.
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Berthoz, Nicolas, Denis Branque, Henry Wong, and Didier Subrin. "TBM soft ground interaction: Experimental study on a 1 g reduced-scale EPBS model." Tunnelling and Underground Space Technology 72 (February 2018): 189–209. http://dx.doi.org/10.1016/j.tust.2017.11.022.
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Wang, Shimin, Xixi Lu, Xianming Wang, Chuan He, Xin Xia, Lei Ruan, and Yunqi Jian. "Soil Improvement of EPBS Construction in High Water Pressure and High Permeability Sand Stratum." Advances in Civil Engineering 2019 (May 29, 2019): 1–9. http://dx.doi.org/10.1155/2019/4503219.
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A mud-water balance shield is the preferred method for the high permeability and high water pressure stratum, but when restricted by construction and environmental conditions, the shield must be constructed with the earth pressure balance shield (EPBS). The risk of slag spraying is extremely high during construction, and this often results in great hidden dangers that threaten workers’ safety during the construction of the tunnel. Slag improvement is an effective measure to prevent slag spraying, and the relevant research is bringing more and more attention to this activity. Based on the background for the tunnel project of Shangteng-Dadao Section of the No. 1 line for Fuzhou Rail Transit, ratio method is proposed for the combined application of sodium bentonite-carboxymethyl cellulose-polyacrylamide adopted by laboratory test focusing on the challenge of residual soil spraying for earth pressure balance shield under the stratum with high water pressure and high permeability; consequently, the best improvement program is suggested for the construction using earth pressure balance shield on this typical kind of stratum, which can be briefly described as the respective mixing of 2.5% and 0.5% accounting for the sand volume by swelling soil with a concentration of 10%, sodium bentonite-CMC mixed mud with a concentration of 5%, and polyacrylamide solution with a concentration ranging from 3% to 4%; furthermore, the results for the field application are random inspected.
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Burton, Mark. "Economy and planet: a blind spot for community psychology?" Universitas Psychologica 14, no. 4 (January 19, 2016): 1339. http://dx.doi.org/10.11144/javeriana.upsy14-4.epbs.
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Conventional economics shares a number of characteristics with mainstream psychology: individualism, acontextualism, and both social and ecological irrelevance. Community psychology has been one response to the shortcomings of mainstream psychology, but has not typically engaged with criticisms of the conventional economics with which it shares assumptions, nor with the economic dimension of community. I reflect on experience promoting alternatives to the dominant economic growth / global competitiveness policy paradigm in the region of Manchester, England, and on the community psychological nature of this project. Community psychology can help articulate an alternative set of values and provide conceptual and practical tools for counter-hegemonic social movements, but the path from community psychology praxis to social movement praxis is not obvious
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Mohamad, Wassim, Emmanuel Bourgeois, Alain Le Kouby, Fabien Szymkiewicz, Agathe Michalski, Denis Branque, Nicolas Berthoz, Laurent Soyez, and Charles Kreziak. "Full scale study of pile response to EPBS tunnelling on a Grand Paris Express site." Tunnelling and Underground Space Technology 124 (June 2022): 104492. http://dx.doi.org/10.1016/j.tust.2022.104492.
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Chen, Ren-Peng, Xing-Tao Lin, Xin Kang, Zhi-Quan Zhong, Yuan Liu, Pin Zhang, and Huai-Na Wu. "Deformation and stress characteristics of existing twin tunnels induced by close-distance EPBS under-crossing." Tunnelling and Underground Space Technology 82 (December 2018): 468–81. http://dx.doi.org/10.1016/j.tust.2018.08.059.
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Carrieri, Giampiero, Enrico Fornari, Vittorio Guglielmetti, and Roberto Crova. "Torino metro line 1: Use of three TBM-EPBs in very coarse grained soil conditions." Tunnelling and Underground Space Technology 21, no. 3-4 (May 2006): 274–75. http://dx.doi.org/10.1016/j.tust.2005.12.134.
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Zheng, Gang, Tianqi Zhang, and Yu Diao. "Mechanism and countermeasures of preceding tunnel distortion induced by succeeding EPBS tunnelling in close proximity." Computers and Geotechnics 66 (May 2015): 53–65. http://dx.doi.org/10.1016/j.compgeo.2015.01.008.
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Berthoz, Nicolas, Denis Branque, Henry Wong, and Didier Subrin. "Stress measurement in partially saturated soils and its application to physical modeling of tunnel excavation." Canadian Geotechnical Journal 50, no. 10 (October 2013): 1077–87. http://dx.doi.org/10.1139/cgj-2013-0154.
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The capacity of a commercially available miniature pressure sensor for measuring stress evolutions in a partially saturated soil under quasi-static loads is studied, in view of its later application in laboratory-scale physical models. An extensive calibration program is first performed on a triaxial cell under isotropic loadings. These calibration tests provide useful data for assessing the uncertainty in stress measurements, especially in the case of partially saturated granular materials. Notably, influences of soil density, water content, and average grain size on stress measurements are quantified. Following these tests, an example of stress measurements on an original reduced-scale model of “earth pressure balance shield” (EPBS) is presented, which involves three-dimensional arching effects developing around the shield during excavation.
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Athwart, Davis Odhiambo, Boniface Ndinya, and Paul Baki. "Effects of 15th January 2010 Annular Solar Eclipse on Traveling Ionospheric Disturbances and Equatorial Plasma Bubbles over Low Latitude Regions of East Africa." Advances in Astronomy 2022 (September 21, 2022): 1–18. http://dx.doi.org/10.1155/2022/5263997.
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The influence of the 15th January 2010 annular solar eclipse on traveling ionospheric disturbances (TIDs) and equatorial plasma bubbles (EPBs) is studied using data from six global navigation and satellite system (GNSS) receivers spread across the path of annularity over the low latitude region of East Africa. The GNSS receivers are stationed at Nairobi (RCMN), Malindi (MAL2), and Eldoret (MOIU) in Kenya; Mbarara (MBAR) in Uganda; Kigali (NURK) in Rwanda; and Mtwara (MTWA) in Tanzania. The study period ranges from 12th to 18th January 2010, three days before and after the 15th January 2010 annular solar eclipse. The year 2010 marked the beginning phase of solar cycle 24, evidently observed in low total electron content (TEC) values and the disturbed storm time index (Dst). The eclipse started at 7 : 06 LT and ended at 10 : 14 LT, with MOIU and RCMN experiencing eclipse magnitudes of 0.946 and 0.93, respectively. The maximum obscuration occurred between 8 : 21 LT and 8 : 34 LT across most of the stations. A detrending on vertical TEC (VTEC) derived from GNSS receivers across or close to the path of totality revealed a reduction of ∼2-3 TECU during the maximum phase of the eclipse. The level of reduction was highly close to the totality path and decreased smoothly away from the totality path. Using a background polynomial fitting technique on diurnal TEC, we analyzed TIDs along NURK-MBAR-MOIU and MOIU-RCMN-MAL2 GPS arrays. The results revealed a wavelike perturbation with a virtual horizontal velocity of 830m/s and ∼1 TECU amplitude propagating eastward along the MOIU-RCMN-MAL2 GPS array. The study reports a moderate scintillation activity of 0.5 ≤ ROTI ≤ 0.9 values, demonstrating the presence of few EPBs over the region. The results show a latitudinal variation in GPS-TEC scintillation activities and suggest a possible influence of the eclipse on the observed increase in average scintillation levels across East Africa.
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Wang, Xin, Yingda Zhang, Wen Zhao, Zhaopeng Wang, Zhiguo Wang, and Ying Wang. "Research on optimizing performance of new slurries for EPBS soil conditioning based on response surface method." Construction and Building Materials 375 (April 2023): 130818. http://dx.doi.org/10.1016/j.conbuildmat.2023.130818.
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