Fuor observations III. FU Orionis during 1984?1990. A remarkable change in the brightness decrease rate

Astrophysics ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 257-266 ◽  
Author(s):  
M. A. Ibragimov
Keyword(s):  
Remarkable Change ◽  
Decrease Rate ◽  
Brightness Decrease

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

Continuity and Change in Patriarchal Structure: Recent Trends in Rural Bangladesh

2018 ◽  
Vol 4 (1) ◽  
pp. 117
Author(s):  
Main Ud-din
Keyword(s):  
Remarkable Change ◽  
Continuity And Change ◽  
Traditional Gender Roles ◽  
Structure And Agency ◽  
Patriarchal Ideology ◽  
Transnational Communication ◽  
To Come ◽  
Gender Based ◽  
Traditional Pattern ◽  
Village Life

This paper is about the transformation in the patriarchal structure of Rashidpur village in Munshiganj district, Bangladesh following overseas migration of men leaving their women in the village. In doing so, the study explores the continuity and changes in the discourse and practices of traditional gender roles in a patriarchal Muslim society considering the perspective of both men and women. The study pays especial attention to transnational communication of the villagers, the changes in their gender based mobility and its contribution to the changes in patriarchal ideology. The study is based on ethnographic fieldwork, which examines whether the changes are sustainable or temporal for a period when the husbands are abroad and what happens to the practices when the husbands permanently return. Though the findings of the study indicate the diversity and complexity of practices, migration of men increases the mobility of the left behind women. Again, the entrance of cell phone, TV and satellite channels and transnational communication of women have significantly changed their agency as individuals. Consequently, many young wives like to come out of the domination of their in-laws and live in separate households instead of previous joint arrangement. The overall findings of the study show a remarkable change in the traditional pattern of village life. The study contextualizes structure and agency to understand how patriarchal structure influences individuals and how individuals play a role to transform the structure in exchange through their mobility, activities and resistance when the migrants are abroad.

Effectiveness of Ayurvedic intervention in Primary Open Angle Glaucoma (Kaphaja Adhimantha) - A Case Study

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Dr. Ratheesh P. ◽  
Dr. Abhayadev A. ◽  
Dr. Varsha Sumedhan ◽  
Dr. Meghna P P. ◽  
Dr. Srinivasan M ◽  
...  
Keyword(s):  
Visual Field ◽  
Structural Changes ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Treatment Protocol ◽  
Clinical Findings ◽  
Field Analysis ◽  
Open Angle ◽  
Remarkable Change ◽  
Related Disorder

Glaucoma is a diverse group of disorders affecting the eye with a common characteristic potentially progressive optic neuropathy that is determined by both structural changes and functional deficit in which IOP is a key modifiable factor. In Primary Open Angle Glaucoma (POAG), IOP independent mechanisms of glaucomatous nerve damage and visual field loss with unobstructed angle of anterior chamber is observed. The patient has reported gradual diminution of peripheral aspect of visual field (Rt. eye - 6/12 and Lt. eye - 6/12 on Snellen’s distant vision chart) in both eyes for 2 years. There was marked peripheral field defect on both confrontation test and perimetry visual field analysis test. The disease shows clinical similarity with Kaphaja Adhimantha, a disease affecting the whole eye mentioned in Susruta Samhita and Ashtanga Hrudaya. It is a chronic disease comes under life style related disorder. Dukhena Roopam Pasyathi (distorted image or constricted visual field), Sirodukha (headache), Srava (watering), Kandu (itching), Pamsupoornatha (foreign body sensation), Aviladarsana (diminished vision) and Gourava (heaviness of eye and head) are the clinical findings explained in the context of Kaphaja Adhimantha. These clinical finding mentioned in classical literature shows resemblance with POAG. The meticulous deployment of kaphaja Abhisyandha- Adhimantha treatment protocol can be used to prevent the progression of ganglionic damage and preservation of eye sight. The logical interpretation on the basis of both subjective and objective clinical findings concluded the diagnosis as Kaphaja Adhimantha and treatment principle adopted was Apatharpana, Kaphahara, Abhisyandhahara and Srothovisodhana. After treatment his vision has improved as 6/6 (Rt. Eye) and 6/6 (Lt. Eye) and remarkable change in field analysis. The study discusses about the effectiveness of Ayurvedic management in POAG.

scholarly journals Study on the effect of Weber Number to heat transfer of multiple droplets on hot stainless steel surface

2018 ◽  
Vol 154 ◽  
pp. 01114 ◽  
Author(s):  
Aria Riswanda ◽  
Indro Pranoto ◽  
Deendarlianto ◽  
Indarto ◽  
Teguh Wibowo
Keyword(s):  
Stainless Steel ◽  
Surface Temperature ◽  
Weber Number ◽  
Steel Surface ◽  
Cooling System ◽  
Spray Cooling ◽  
Stainless Steel Surface ◽  
Temperature Decrease ◽  
Evaporation Time ◽  
Decrease Rate

Multiple droplets are drops of water that continuously dropped onto a surface. Spray cooling is an application of the use of droplet on a cooling system. Spray cooling is usually used in a cooling system of electronic devices, and material quenching. In this study, correlations between Weber number and surface temperature decrease rate during multiple droplets impingement are investigated and analyzed. Visualization process is used to help determine the evaporation time of droplets impingement by using high speed camera. Induction stove is used to maintain a stainless steel surface temperature at 120°C, 140°C, and 160°C. The Weber number was varied at 15, and 52.5 to simulate low and medium Weber number. The result of this study shows that increase in Weber number does not increase the temperature decrease rate noticeably. Whereas the Weber number decrease the time required for surface temperature to reach its lowest surface temperature. It was also found that for low and medium Weber number, Weber number affect the evaporation time of multiple droplets after impingement.

Studies the Properties of Polyaspartic Polyurea Coated Concrete under Coaction of Salt Fog and Freeze-Thaw

2012 ◽  
Vol 455-456 ◽  
pp. 781-785
Author(s):  
Ping Lu ◽  
Xin Mao Li ◽  
Xue Qiang Ma ◽  
Wei Bo Huang
Keyword(s):  
Elastic Modulus ◽  
Frost Resistance ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw ◽  
Decrease Rate ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Salt Fog

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.

scholarly journals On the Relationship between Low Latitude Scintillation Onset and Sunset Terminator over Africa

2021 ◽  
Vol 13 (11) ◽  
pp. 2087
Author(s):  
Mogese Wassaie Mersha ◽  
Elias Lewi ◽  
Norbert Jakowski ◽  
Volker Wilken ◽  
Jens Berdermann ◽  
...  
Keyword(s):  
Moving Boundary ◽  
Occurrence Rate ◽  
Scintillation Index ◽  
Small Scale ◽  
Bahir Dar ◽  
Remarkable Change ◽  
Equatorial Africa ◽  
Night Side ◽  
Solar Terminator ◽  
First Time

The solar terminator is a moving boundary between day-side and night-side regions on the Earth, which is a substantial source of perturbations in the ionosphere. In the vicinity of the solar terminator, essential parameters like S4 index measurements are widely analyzed in order to monitor and predict perturbations in the ionosphere. The utilization of the scintillation index S4 is a well-accepted approach to describe the amplitude/intensity fluctuation of a received signal, predominantly caused by small-scale irregularities of the ionospheric plasma. We report on the longitudinal daily and seasonal occurrence of GNSS signal scintillations, using the data derived from the GNSS stations in Bahir Dar, Ethiopia, Lomé, Togo and Dakar, Senegal. The observed seasonal climatology of GNSS signal scintillations in equatorial Africa is adequately explained by the alignment of the solar terminator and local geomagnetic declination line. It should be pointed out that the strongest scintillations are most frequently observed during the time when the solar terminator is best aligned with the geomagnetic declination line. At all three stations, the comparison of computational and observational results indicated that the scintillation activity culminated around equinoxes in the years 2014, 2015 and 2016. Comparatively, the western equatorial Africa sector has the most intense, longest-lasting, and highest scintillation occurrence rate in equinoctial seasons in all three years. For the first time, we show that the seasonal variation of the scintillation peaks changes systematically from west to east at equatorial GNSS stations over Africa. A detailed analysis of the solar day–night terminator azimuth at ionospheric heights including the time equation shows that the scintillation intensity has a maximum if the azimuth of the terminator coincides with the declination line of the geomagnetic field. Due to the remarkable change of the declination by about 10° at the considered GNSS stations, the distance between scintillation peaks increases by 46 days when moving westward from the Bahir Dar to the Dakar GNSS station. The observations agree quite well with the computational results, thus confirming Tsunoda’s theory.

scholarly journals Transparent silver and other metallic films

1908 ◽  
Vol 81 (548) ◽  
pp. 301-310 ◽  
Keyword(s):  
White Light ◽  
Electric Resistivity ◽  
Metallic Film ◽  
Moderate Temperature ◽  
Metallic Films ◽  
Remarkable Change ◽  
Simple Method ◽  
Glass Plates ◽  
Cold Gas

It is well known that when thin leaves of gold or silver are mounted upon glass and heated to a temperature which is well below a red heat, a remarkable change of properties takes place, whereby the continuity of the metallic film is destroyed. The result is that white light is now freely transmitted, reflection is correspondingly diminished, while the electric resistivity is enormously increased. A simple method of illustrating this extraordinary change is to mount a sheet of silver leaf between two clean lantern plates, clip them lightly together by means of wire paper fasteners or other suitable means, and then heat gradually to a temperature of not more than 500°C. This can be done con­veniently by placing the plates on a thin fire-brick in a cold gas muffle, and then raising the temperature to the desired point. The gas should now be turned off, and the glass plates allowed to cool slowly, so as to avoid cracking. They can then be bound with strips like an ordinary lantern plate, and a permanent example of transparent silver is obtained. It will be found that such a plate transmits the light of the electric lantern almost as readily as ordinary glass, and does not produce any change of colour. The great trans­parency of the film may be shown by placing the plate upon printing or writing, and photographing the characters through the plate. Every detail of the characters can be reproduced with remarkable clearness. At first sight it is perhaps difficult to conceive that so distinct an impression could be obtained through what was originally a perfectly opaque sheet of silver, and which has only been once heated to a moderate temperature.

Continuity and change in the vegetation of a Central European oakwood

The Holocene ◽  
2012 ◽  
Vol 23 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Eva Jamrichová ◽  
Péter Szabó ◽  
Radim Hédl ◽  
Petr Kuneš ◽  
Přemysl Bobek ◽  
...  
Keyword(s):  
18Th Century ◽  
Driving Forces ◽  
Multiple Use ◽  
Scotch Pine ◽  
Remarkable Change ◽  
14Th Century ◽  
Wood Pasture ◽  
Long Run ◽  
Human Management ◽  
Fire Disturbances

The issue of continuity in deciduous oakwood vegetation has been in the forefront of woodland ecological studies for many decades. The two basic questions that emerge from existing research are whether or not oakwoods can be characterized by long-term stability and what may be the driving forces of the observed stability or change. To answer these questions in a well-defined case study, we examined the history of a large subcontinental oakwood (Dúbrava) in the southeastern Czech Republic with interdisciplinary methods using palaeoecological and archival sources. Palaeoecology allowed us to reconstruct the vegetation composition and fire disturbances in Dúbrava in the past 2000 years, while written sources provided information about tree composition and management from the 14th century onwards. The pollen profiles show that the present oakwood was established in the mid-14th century with an abrupt change from shrubby, hazel-dominated vegetation to oak forest. This change was most probably caused by a ban on oak felling in ad 1350. From the 14th to the late 18th centuries Dúbrava had multiple uses, of which wood-pasture and hay-cutting kept the forest considerably open. The second remarkable change was dated to the late 18th century, when multiple-use management was abandoned and Dúbrava was divided into pasture-only and coppice-only parts. The last major shift occurred in the mid-19th century, when modern forestry and Scotch pine plantation became dominant. We conclude that Dúbrava Wood did not show stability in the long run and that its species composition has dramatically changed during the last two millennia. The most important driving force in the shaping and maintenance of the unique vegetation of Dúbrava was human management.

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