Untitled

Singh, Ashok K.; Narayan, Deo; Singh, R. P.

doi:10.1023/a:1022420426950

“…Later the technology passed across regions and cultures like Greeks, Romans, old world Africans, Mexicans and was also evident in Peru (TRMIC 1991;Dogan et al 2008). According to Zohary and Hopf (1994), dye yielding plants have been cultivated in southwest Asia since ancient times and earliest persisting indication of textile dyeing comes from an over 5,000-year-old piece of cloth dyed with natural madder (Rubia cordifolia) discovered at Mohenjo-Daro (Singh 2002;Mahanta and Tiwari 2005;Das and Mondol 2012). Natural dyes are colorants derived from plants, invertebrates or minerals, while majority of natural dyes are extracted from vegetable or plant sources like roots, berries, bark, leaves, wood and other biological sources such as fungi and lichens.…”

Section: Introductionmentioning

confidence: 99%

“…The use of natural dyes has been declining since the discovery of synthetic dyes (Singh 2002). However, many studies have found that synthetic dyes are harmful to human health as well as environment (Kwok et al 1999;Singh and Singh 2002;Cristea et al 2003;Mahanta and Tiwari 2005;Seker et al 2006). Natural dyes are environment and skin friendly; for example, turmeric, the brightest of naturally occurring yellow dye is a powerful antiseptic and revitalizes the skin, while indigo yields a cooling sensation.…”

Section: Introductionmentioning

confidence: 99%

Traditional dye yielding plants of Tripura, Northeast India

Sutradhar

¹

,

Deb

²

,

Majumdar

³

et al. 2015

View full text Add to dashboard Cite

Sutradhar B, Deb D, Majumdar K, Datta BK. 2015. Traditional dye yielding plants of Tripura,. This present paper deals with the survey of traditional dye yielding plants, their ethnobotanical usage and cultural practices by the different ethnic communities of Tripura. Field investigation was carried out in different villages and adjacent forest pockets in South and West district of the State. The ethnobotanical information was collected based on semi-structured questioner, personal interviews and group discussion among the major ethnic communities of Tripura. The study reports a checklist of 39 species of dye yielding plants belonging to 35 genera and 26 families documented along with their vernacular name, habit, parts use. The active coloring agents were also listed for each plant based on earlier reports. Natural dye yielding plants have immense significance in the socio-economic and socio-cultural life of indigenous ethnic people and if we promote these products in a managed way then efforts towards preservation of traditional knowledge and local biodiversity will be more fruitfully achieved.

show abstract

“…Starting with one of the first works [Ginzburg, 1963], the magnetoionic theory has generally been applied to dispersion properties of ionospheric plasma in ion gyrofrequencies. These are the socalled problems of crossover and ion whistlers (see, e.g., [Singh et al, 2002;Vavilov, Shklyar, 2016]). In some papers, the multicomponent plasma model has been considered in connection with particular issues.…”

Section: Introductionmentioning

confidence: 99%

Peculiarities of ULF wave characteristics in a multicomponent ionospheric plasma

Kotik

¹

,

Orlova²,

Yashnov³

2022

Solar-Terrestrial Physics

1

0

View full text Add to dashboard Cite

We have examined the properties of low-frequency electromagnetic waves in multicomponent ionospheric plasma in the 1–30 Hz band, using the magnetoionic theory. Complex permittivity tensor components and refractive indices of normal waves (ordinary and extraordinary) were calculated at altitudes from 80 to 750 km. The calculations show that the refractive indices are highly dependent on frequency and height. Polarization of ordinary and extraordinary waves is elliptical over the entire range of the frequencies investigated. The refractive index and the polarization of normal waves are demonstrated to tend to magnetohydrodynamic (MHD) values only at frequencies lower than 1 Hz. The group velocity vector of an extraordinary wave is not directed along the magnetic field, as follows from the MHD approximation, but it lies inside a cone within ±(5–10) degrees, depending on frequency. The group velocity vector of an ordinary wave is practically independent of the angle with the geomagnetic field as in the MHD approximation. The proposed method for calculating the characteristics of normal waves in the ionosphere can be used to study ULF wave propagation from both natural and artificial ionospheric sources, which arise under the action of powerful HF radio waves in the lower and upper ionosphere.

show abstract

“…Традиционно, начиная с одной из первых работ [Гинцбург, 1963], магнитоионная теория применяется при исследовании дисперсионных свойств ионосферной плазмы в области гирочастот ионов. Это так называемые проблемы кроссовера и ионных свистов (см., например, [Singh et al, 2002;Vavilov, Shklyar, 2016]). В некоторых работах модель многокомпонентной плазмы рассматривалась в связи с частными вопросами.…”

Section: Introductionunclassified

Peculiarities of ULF wave characteristics in a multicomponent ionospheric plasma

Kotik

¹

,

Orlova²,

Yashnov³

2022

Solnechno-Zemnaya Fizika

0

View full text Add to dashboard Cite

We have examined the properties of low-frequency electromagnetic waves in multicomponent ionospheric plasma in the 1–30 Hz band, using the magnetoionic theory. Complex permittivity tensor components and refractive indices of normal waves (ordinary and extraordinary) were calculated at altitudes from 80 to 750 km. The calculations show that the refractive indices are highly dependent on frequency and height. Polarization of ordinary and extraordinary waves is elliptical over the entire range of the frequencies investigated. The refractive index and the polarization of normal waves are demonstrated to tend to magnetohydrodynamic (MHD) values only at frequencies lower than 1 Hz. The group velocity vector of an extraordinary wave is not directed along the magnetic field, as follows from the MHD approximation, but it lies inside a cone within ±(5–10) degrees, depending on frequency. The group velocity vector of an ordinary wave is practically independent of the angle with the geomagnetic field as in the MHD approximation. The proposed method for calculating the characteristics of normal waves in the ionosphere can be used to study ULF wave propagation from both natural and artificial ionospheric sources, which arise under the action of powerful HF radio waves in the lower and upper ionosphere.

show abstract

Untitled

Cited by 4 publications

References 17 publications

Traditional dye yielding plants of Tripura, Northeast India

Traditional dye yielding plants of Tripura, Northeast India

Peculiarities of ULF wave characteristics in a multicomponent ionospheric plasma

Peculiarities of ULF wave characteristics in a multicomponent ionospheric plasma

Contact Info

Product

Resources

About