Characteristics of polar coronal hole jets

High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be $\approx$ 27 km s$^{-1}$. The average outward speed of the first jet is $\approx 171$ km s$^{-1}$, well below the escape speed, hence if simple ballistic motion is considered, the plasma will not escape the Sun. The second jet was observed in the south polar coronal hole with three XRT filters, namely, C$_{-}$poly, Al$_{-}$poly, and Al$_{-}$mesh filters. We observed that the second jet drifted at all altitudes along the jet with the same drift speed of $\simeq$ 7 km s$^{-1}$. The enhancement in the light curves of low-temperature EIS lines in the later phase of the jet lifetime and the shape of the jet's stack plots suggests that the jet material is falls back, and most likely cools down. To support this conclusion, the observed drifts were interpreted within a scenario where reconnection progressively shifts along a magnetic structure, leading to the sequential appearance of jets of about the same size and physical characteristics. On this basis, we also propose a simple qualitative model that mimics the observations.Comment: Accepted Astronomy and Astrophysic

Study of length of umbilical cord and fetal outcome: a study of 1000 deliveries

Background: Human embryo develops inside the body of the mother. One of the important part of the fetoplacental unit is the umbilical cord. The umbilical cord is the lifeline of the fetus. Objective of present study was to investigate the correlation of umbilical cord length with fetal parameters like APGAR score, sex, weight, and length, and its effect on labor.Methods: This prospective study conducted in the Department of OBG of VIMS, Bellary, from 1st February 2016 to 31st January 2017. The 1000 pregnant women of >37 weeks were studied following delivery for length of umbilical cord, any loop around neck, trunk, shoulder and number of loops of cord; knots of cord etc. Fetal parameters recorded were sex, weight, and length of the newborn and APGAR score at 1 and 5 min.Results: Cord length varied from 22 to 126 cm. The mean cord length was 66 cm (±10 cm). Maximum cases have cord length of 61and 70 cm. Lower 5th percentile and upper 5th percentile considered as short and long cord. Short-cord group was associated with significantly higher (p<0.05) incidence of LSCS cases. The incidence of all types of cord complications increases as the cord length increases (p<0.001). Nuchal cords had higher mean cord length and as the number of loops in a nuchal cord increases to two or more loops, the operative interference and fetal heart abnormalities increases. Fetal heart rate abnormalities and birth asphyxia increase with extremes of cord length (p<0.001).Conclusions: Short and long cords are associated with increased incidence of cord complications, operative interference, intrapartum complications, increased fetal heart rate abnormalities, and birth asphyxia. But cord length did not vary according to the weight, length, and sex of the baby

Sensitization of Colour Reactions of Lanthanides & Chrome Azurol S with Some Cationic Detergents

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Finite Element Development for Analytical of Smart Structure

In the present study, a numerical solution bas ed on the finite element method has been dev eloped to analyze the deformation, electr ic potentials of a piezoelectric smart structure s ubjected to external mechanical or electrical lo adings.The formulation of the finite element for st atic analysis has been presented based on isoparametric formulation. The element considered in the present study is eight noded hexahedral elements. A computer code based on the above formulation has been developed using MA TLAB software to solve the three dimensional structures integrated with piezoelements. The experiments have been conducted on the piezoelectric smart structures consisting carbon epoxy beam and the results obtain ed were used for validating the present finite element code developed and found to have good agreemen

Project ambidexterity: case of recovering schedule delay in a brownfield airport project in India

Planning deficiencies and consequent execution delays are likely to persist in infrastructure development projects. However, recovery of schedule delay is a less researched area. This case research, using a two-stage inquiry modeled on the grounded theory, studied the schedule delay recovery during the execution phase of a brownfield airport construction project. The analyses generated contextual evidence and ambidexterity was found to be the key underlying phenomenon for successful recovery measures. The empirical learning was validated with literature and can be used by practitioners looking to institute schedule recovery measures

Subsidence Movements and Structural Damage Related to an Abandoned Coal Mine

An area in southwestern Illinois has been experiencing surface and subsurface movements with associated damage to surface structures. The area is underlain by an abandoned, partially extracted room-and-pillar underground coal mine. Instrumentation included TDR (Time Domain Reflectometry), Inclinometers, Sondex, Tiltplates, and precision land surveys. This paper presents the results of a 16-month cooperative study between the Department of Mining Engineering at SIUC and a local coal company

Statistical Study of Plasmoids associated with post-CME Current Sheet

We investigate the properties of plasmoids observed in the current sheet formed after an X-8.3 flare followed by a fast CME eruption on September 10, 2017 using Extreme Ultraviolet (EUV) and white-light coronagraph images. The main aim is to understand the evolution of plasmoids at different spatio-temporal scales using existing ground- and space-based instruments. We identified the plasmoids in current sheet observed in the successive images of {\it Atmospheric Imaging Assembly} (AIA) and white-light coronagraphs, K-Cor and LASCO/C2. We found that the current sheet is accompanied by several plasmoids moving upwards and downwards. Our analysis showed that the downward and upward moving plasmoids have average width of 5.92 Mm and 5.65 Mm, respectively in the AIA field of view (FOV). However, upward moving plasmoids have average width of 64 Mm in the K-Cor which evolves to a mean width of 510 Mm in the LASCO/C2 FOV. Upon tracking the plasmoids in successive images, we observe that downward and upward moving plasmoids have average speeds of $\sim$272 km s$^{-1}$ and $\sim$191 km s$^{-1}$ respectively in the EUV passbands. We note that the plasmoids become super-Alfv\'enic when they reach at LASCO FOV. Furthermore, we estimate that the null-point of the current sheet at $\approx$ 1.15 R$_\odot$ where bidirectional plasmoid motion is observed. We study the width distribution of plasmoids formed and notice that it is governed by a power law with a power index of -1.12. Unlike previous studies there is no difference in trend for small and large scale plasmoids. The presence of accelerating plasmoids near the neutral point indicates a longer diffusion region as predicted by MHD models.Comment: Accepted for the publication in Astronomy & Astrophysics (A&A). 10 pages, 11 figures. Animations can be found at https://www.dropbox.com/sh/g0wjq2awxai1hy4/AAClkTHPFkTa5JU-Zulf9a75a?dl=