Correlation analysis of three influencing factors and the dust production rate for a free-falling particle stream

Particuology ◽  
2017 ◽  
Vol 34 ◽  
pp. 126-133 ◽  
Author(s):  
Mengjie Duan ◽  
Yi Wang ◽  
Xiaofen Ren ◽  
Xinrui Qu ◽  
Yingxue Cao ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Production Rate ◽  
Influencing Factors ◽  
Dust Production ◽  
Particle Stream ◽  
Free Falling

Experimental Investigation of Dust Amount from Free Falling Particle Stream Effected by Deflector Curvature of Dust Suppression

2013 ◽  
Vol 864-867 ◽  
pp. 1789-1792 ◽  
Author(s):  
Ze Qin Liu ◽  
Zhen Jing Wu ◽  
Ze Peng Feng
Keyword(s):  
Experimental Investigation ◽  
Dust Control ◽  
Emissions Reduction ◽  
Fugitive Dust ◽  
Bulk Materials ◽  
Dust Suppression ◽  
Suppression Effect ◽  
Particle Stream ◽  
Free Falling ◽  
The Relationship

This paper focuses on the study of the curvatures of deflector installed on the below receiving device to effect the dust amount from the free falling particle stream. The deflector curvature was artificially controlled to limit the fugitive dust direction which was generated by the collision between the free falling bulk materials and the receiving device. This method was used to improve efficiency of the dust control system to exhaust fugitive dust, and to achieve the targets of energy conservation and emissions reduction. The experimental method was adopted to explore the relationship between the deflector curvature and the producing dust quantity. The experimental results indicated that, the dust suppression effect containing deflector contained a certain radian was more remarkable, when the height of the free falling of bulk materials was constant. The producing dust quantity decreased slightly with the deflector curvature increasing, and then increased rapidly. When the deflector curvature was 0.045 cm-1 or 0.060cm-1, the minimum of producing dust quantity could be obtained, and the dust removal effect might be significant.

scholarly journals 523676 (2013 UL10): the first active red centaur

2018 ◽  
Vol 620 ◽  
pp. A93 ◽  
Author(s):  
E. Mazzotta Epifani ◽  
E. Dotto ◽  
S. Ieva ◽  
D. Perna ◽  
P. Palumbo ◽  
...  
Keyword(s):  
Production Rate ◽  
Canary Islands ◽  
Colour Index ◽  
Nucleus Size ◽  
Dust Production ◽  
La Palma ◽  
Upper Limit ◽  
Nucleus Surface ◽  
Perihelion Passage

Aims. We present observations of 523676 (2013 UL10), a centaur orbiting between Jupiter and Uranus that is dynamically similar to the few tens of active centaurs that are currently known. Methods. We analysed visible BVR images of the centaur obtained at the Telescopio Nazionale Galileo (La Palma, Canary Islands, Spain) to investigate the weak comet-like activity and to derive information on the nucleus surface colours and size. Results. Centaur 523676 (2013 UL10) is the only centaur known so far that has both comet-like activity and red surface colours: its nucleus has a colour index [B – R] = 1.88 ± 0.11. The nucleus R magnitude (R = 20.93 ± 0.09) allowed us to derive an upper limit for its nucleus size of D ≤ 10 km. We estimated its dust production rate to be Qd ~ 10 kg s−1 at 6.2 au (just after its perihelion passage), resulting in a timescale for the surface blanketing process τB of approximately tens of years, which is very short with respect to typical dynamical lifetime inside the group. Future monitoring of 523676 (2013 UL10) is needed to further constrain the blanketing model for active centaurs and its timescale.

scholarly journals Narrow-band photometry of Long Period Comets with TRAPPIST telescopes in 2019-2020

2020 ◽  
Author(s):  
Youssef Moulane ◽  
Emmanuel Jehin ◽  
Francisco José Pozuelos ◽  
Jean Manfroid ◽  
Zouhair Benkhaldoun ◽  
...  
Keyword(s):  
Solar System ◽  
Production Rate ◽  
Heliocentric Distance ◽  
Narrow Band ◽  
Maximum Activity ◽  
The Sun ◽  
Water Production ◽  
Dust Production ◽  
Long Period ◽  
Water Production Rate

<p>Long Period Comets (LPCs) have orbital periods longer than 200 years, perturbed from their resting place in the Oort cloud. Such gravitational influences may send these icy bodies on a path towards the center of the Solar system in highly elliptical orbits. In this work, we present the activity and composition evolution of several LPCs observed with both TRAPPIST telescopes (TS and TN) during the period of 2019-2020. These comets include: C/2017 T2 (PANSTARRS), C/2018 Y1 (Iwamoto), C/2018 W2 (Africano), and disintegrated comet C/2019 Y4 (ATLAS). We monitored the OH, NH, CN, C<sub>2</sub> and C<sub>3</sub> production rates evolution and their chemical mixing ratios with respect to their distances to the Sun as well as the dust production rate proxy (A(0)fp) during the journey of these comets into the inner Solar system.</p> <p><strong>C/2017 T2 (PANSTARRS)</strong> is a very bright comet which was discovered on October 2, 2017 when it was 9.20 au from the Sun. We started observing this comet with TS at the beginning of August 2019 when it was at 3.70 au. The comet made the closest approach to the Earth on December 28, 2019 at a distance of 1.52 au and it passed the perihelion on May 4, 2020 at 1.61 au. The water production rate of the comet reached a maximum of (4,27±0,12)10<sup>28 </sup>molecules/s and its dust production rate (A(0)fp(RC)) also reached the peak of 5110±25 cm on January 26, 2020, when the comet was at 2.08 au from the Sun (-100 days pre-perihelion). At the time of writing, we still monitoring the activity of the comet with TN at heliocentric distance of 1.70 au. Our observations show that C/2017 T2 is a normal LPC.</p> <p><strong>C/2018 Y1 (Iwamoto)</strong> is a nearly parabolic comet with a retrograde orbit discovered on December 18, 2018 by Japanese amateur astronomer Masayuki Iwamoto. We monitored the activity and composition of Iwamoto with both TN and TS telescopes from January to March 2019. The comet reached its maximum activity on January 29, 2019 when it was at 1.29 au from the Sun (-8 days pre-perihelion) with Q(H<sub>2</sub>O)=(1,68±0,05)10<sup>28 </sup>molecules/s and A(0)fp(RC)= 92±5 cm. These measurements show that it was a dust-poor comet compared to the typical LPCs.</p> <p><strong>C/2018 W2 (Africano) </strong>was discovered on November 27, 2018 at Mount Lemmon Survey with a visual magnitude of 20. The comet reached its perihelion on September 6, 2019 when it was at 1.45 au from the Sun. We monitored the comet from July 2019 (r<sub>h</sub>=1.71 au) to January 2020 (r<sub>h</sub>=2.18 au) with both TN and TS telescopes. The comet reached its maximum activity on September 21, 15 days post-perihelion (r<sub>h</sub>=1.47 au) with Q(H<sub>2</sub>O)=(0,40±0,03)10<sup>28 </sup>molecules/s.</p> <p><strong>C/2019 Y4 (ATLAS)</strong> is a comet with a nearly parabolic orbit discovered on December 18, 2019 by the ATLAS survey. We started to follow its activity and composition with broad- and narrow-band filters with the TN telescope on February 22, 2019 when it was at 1.32 au from the Sun until May 3, 2020 when the comet was at a heliocentric distance of 0.90 au inbound. The comet activity reached a maximum on March 22 (r<sub>h</sub>=1.65 au) 70 days before perihelion. At that time, the water-production rate reached (1,53±0,04)10<sup>28 </sup>molecules/s and the A(0)fp reached (1096±14) cm in the red filter. After that, the comet began to fade and disintegrated into several fragments.</p>

scholarly journals Detection of a repeated transit signature in the light curve of the enigma star KIC 8462852: A possible 928-day period

2017 ◽  
Vol 608 ◽  
pp. A132 ◽  
Author(s):  
F. Kiefer ◽  
A. Lecavelier des Étangs ◽  
A. Vidal-Madjar ◽  
G. Hébrard ◽  
V. Bourrier ◽  
...  
Keyword(s):  
Light Curve ◽  
Production Rate ◽  
A Priori ◽  
Ring System ◽  
Striking Similarity ◽  
Dust Production ◽  
High Quality ◽  
Bad Weather ◽  
Absorption Features

As revealed by its peculiar Kepler light curve, the enigmatic star KIC 8462852 undergoes short and deep flux dimmings at a priori unrelated epochs. This star presents nonetheless all other characteristics of a quiet 1 Gyr old F3V star. These dimmings resemble the absorption features expected for the transit of dust cometary tails. The exocomet scenario is therefore most commonly advocated. We reanalysed the Kepler data and extracted a new high-quality light curve to allow for the search of shallow signatures of single or a few exocomets. We discovered that among the 22 flux dimming events that we identified, two events present a striking similarity. These events occurred 928.25 days apart and lasted for 4.4 days with a drop in the star brightness by 1000 ppm. We show that the light curve of these events is well explained by the occultation of the star by a giant ring system or by the transit of a string of half a dozen exocomets with a typical dust production rate of 105–106 kg s-1. Assuming that these two similar events are related to the transit of the same object, we derive a period of 928.25 days. The following transit was expected in March 2017 but bad weather prohibited us from detecting it from ground-based spectroscopy. We predict that the next event will occur between 3−8 October 2019.

Cognition differences and improvement countermeasures of non-technical medical services based on grey correlation analysis

2019 ◽  
Vol 9 (2) ◽  
pp. 155-163
Author(s):  
Hangyu Liu ◽  
Saina Liu ◽  
Lizhong Duan ◽  
Chongxu Zhang ◽  
Lili Yin ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Influencing Factors ◽  
Design Methodology ◽  
Doctoral Degree ◽  
Medical Services ◽  
Literature Analysis ◽  
Expert Interviews ◽  
Content Type ◽  
Grey Correlation ◽  
Grey Correlation Analysis

Purpose The purpose of this paper is to explore the rationality differences of cognition of non-technical medical services in different groups, and to provide countermeasures for improving non-technical medical services. Design/methodology/approach Literature analysis, expert interviews, questionnaire survey and frequency analysis were taken to reveal the influencing factors of non-technical medical services. Grey correlation methods were taken to compare the rationality differences of cognition of non-technical medical services by analysis influencing factors’ scores marked by different groups. Findings A total of 12 influencing factors of non-technical medical services were obtained, including “doctor’s working career”, “doctor’s strict implementation of medical treatment norms and medication guidelines”, “doctor’s service awareness”, etc. And rationality differences of cognition of non-technical medical services were confirmed as follows: the doctors’ cognition was more reasonable compared with patients; the women’s cognition was more reasonable compared with men; the lower aged groups’ cognition was more reasonable compared with higher aged groups; and people with doctoral degree had a less reasonable cognition compared with others. Originality/value The authors systematically discussed the cognition differences of non-technical medical services among different people, and provided some countermeasures reasonably.

scholarly journals Estimating the dust production rate of carbon stars in the Small Magellanic Cloud

2017 ◽  
Vol 473 (4) ◽  
pp. 5492-5513 ◽  
Author(s):  
Ambra Nanni ◽  
Paola Marigo ◽  
Léo Girardi ◽  
Stefano Rubele ◽  
Alessandro Bressan ◽  
...  
Keyword(s):  
Production Rate ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Carbon Stars ◽  
Dust Production

scholarly journals Investigation on the Stress of Chinese Pediatricians Under the Outbreak of COVID-19

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Lan Yang ◽  
Bingbing Zhang ◽  
Xiaoxing Kong ◽  
Weifang Zhou ◽  
Jianmei Tian ◽  
...  
Keyword(s):  
Linear Regression ◽  
Correlation Analysis ◽  
Sleep Quality ◽  
Multiple Linear Regression ◽  
Influencing Factors ◽  
Perceived Stress ◽  
Physical Condition ◽  
Work Experience ◽  
Mental Stress ◽  
Professional Title

Background: The Coronavirus disease 2019 (COVID-19) pandemic has posed a severe threat to international health and the economy. Clinicians, the main staff involved in fighting against the pandemic, are under great pressure. However, relevant mental stress studies are lacking at present. Objectives: This study aimed to explore the mental stress level and its influencing factors among Chinese pediatricians under the outbreak of COVID-19, aiming to provide a certain theoretical basis for relevant psychological intervention among medical staff. Methods: In this cross-sectional study, 352 in-service pediatricians were selected from nine hospitals in Jiangsu province, China, in February 2020. The online survey was performed to collect general information. Meanwhile, the Perceived Stress Scale (PSS-10), Self-rating Anxiety Scale (SAS), and Pittsburgh Sleep Quality Index (PSQI) scale were employed for assessment. Afterward, the stress level and influencing factors among pediatricians were analyzed through descriptive analysis, one-way analysis of variance (ANOVA), correlation analysis, and multiple linear regression analysis. Results: The mean score of PSS-10 showed moderate stress on the whole. Pediatricians from outpatient and emergency departments had significantly higher perceived stress than those from other departments. The perceived stress was significantly associated with age, educational level, professional title, work experience, and physical condition. Stepwise multiple linear regression showed that age, professional title, and physical condition had a linear relationship with the individual’s perceived stress. Besides, Pearson correlation analysis indicated that perceived stress was associated with anxiety level and sleep quality. Conclusions: Under the outbreak of COVID-19, pediatricians suffer from relatively high levels of mental stress. The influencing factors include education, age, professional title, work experience, and physical condition. Typically, the anxiety level and sleep quality are correlated with the mental stress among pediatricians.

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