Nucleation Under Shear Flow

We present a general formalism for calculating the nucleation rates of simply sheared systems [5-6]. We have derived an extension to the conventional Classical Nucleation Theory, explicitly embodying the shear rate. The framework can be used for moderate supercooling, at which temperatures brute-force methods are practically infeasible. We show how the theory can be used to identify shear regimes of ice nucleation behavior for the mW water model, unifying disparate trends reported in the literature [7]. [1] Tschauner, O et al., Science, 359, 1136-1139 (2018) [2] Goswami, A., Singh, J. K., Phys. Chem. Chem. Phys., (2020) [3] Goswami, A., Singh, J. K., J. Phys. Chem. C., in press (2020) [4] Goswami A, Singh JK, J. Chem. Phys. 154, 154502 (2021) [5] Goswami A and Singh JK, Phys. Phys. Chem. Phys. 23, 150402 (2021) [6] Goswami, A, Dalal IS, Singh JK, J. Chem. Phys, 153, 09502 (2021) [7] Goswami, A, Dalal IS, Singh JK, Phys. Rev. Letts, 126, 195702 (2021

Three-dimensional magnetic structure of a sunspot: comparison of the photosphere and upper chromosphere

We investigate the magnetic field of a sunspot in the upper chromosphere and compare it to the field's photospheric properties. We observed the main leading sunspot of the active region NOAA 11124 on two days with the Tenrife Infrared Polarimeter-2 (TIP-2) mounted at the German Vacuum Tower Telescope (VTT). Through inversion of Stokes spectra of the He I triplet at 1083.0 nm, we obtained the magnetic field vector of the upper chromosphere. For comparison with the photosphere we applied height-depended inversions of the Si I 1082.71 nm and Ca I 1083.34 nm lines. We found that the umbral magnetic field strength in the upper chromosphere is lower by a factor of 1.30-1.65 compared to the photosphere. The magnetic field strength of the umbra decreases from the photosphere towards the upper chromosphere by an average rate of 0.5-0.9 G km$^{-1}$. The difference in the magnetic field strength between both atmospheric layers steadily decreases from the sunspot center to the outer boundary of the sunspot, with the field (in particular its horizontal component) being stronger in the chromopshere outside the spot, suggestive of a magnetic canopy. The sunspot displays a twist that on average is similar in the two layers. However, the differential twist between photosphere and chromosphere increases rapidly towards the outer penumbral boundary. The magnetic field vector is more horizontal with respect to the solar surface by roughly 5-20$^\circ$ in the photosphere compared to the upper chromosphere. Above a lightbridge, the chromospheric magnetic field is equally strong as that in the umbra, whereas the lightbridge's field is weaker than its surroundings in the photosphere by roughly 1 kG. This suggests a cusp-like magnetic field structure above the lightbridge.Comment: 12 pages, 15 figures, accepted for publication in A&

Vertical magnetic field gradient in the photospheric layers of sunspots

We investigate the vertical gradient of the magnetic field of sunspots in the photospheric layer. Independent observations were obtained with the SOT/SP onboard the Hinode spacecraft and with the TIP-2 mounted at the VTT. We apply state-of-the-art inversion techniques to both data sets to retrieve the magnetic field and the corresponding vertical gradient. In the sunspot penumbrae we detected patches of negative vertical gradients of the magnetic field strength, i.e.,the magnetic field strength decreases with optical depth in the photosphere. The negative gradient patches are located in the inner and partly in the middle penumbrae in both data sets. From the SOT/SP observations, we found that the negative gradient patches are restricted mainly to the deep photospheric layers and are concentrated near the edges of the penumbral filaments. MHD simulations also show negative gradients in the inner penumbrae, also at the locations of filaments. Both in the observations and simulation negative gradients of the magnetic field vs. optical depth dominate at some radial distances in the penumbra. The negative gradient with respect to optical depth in the inner penumbrae persists even after averaging in the azimuthal direction, both in the observations and, to a lesser extent, also in MHD simulations. We interpret the observed localized presence of the negative vertical gradient of the magnetic field strength in the observations as a consequence of stronger field from spines expanding with height and closing above the weaker field inter-spines. The presence of the negative gradients with respect to optical depth after azimuthal averaging can be explained by two different mechanisms: the high corrugation of equal optical depth surfaces and the cancellation of polarized signal due to the presence of unresolved opposite polarity patches in the deeper layers of the penumbra.Comment: 17 pages, 25 figures, accepted for publication in A&

Social capital for disaster risk reduction and management with empirical evidences from Sundarbans of India

Social capital is a resource which is embedded in every community and it has been observed that it plays an important role in different stages of a disaster. Social capital can be crucial for a community to survive till outside help arrives, in event of a disaster, and many a time it is the only resource that the community can mobilize to respond and recover. This research paper reviewed the contribution of social capital with different empirical evidences from cases across the world and brought it into the perspective of the study area in Sundarbans, India. The study area is frequented by disasters like tropical cyclones and surges, it was observed that the network at the community level is crucial for survival of the community. It also was observed that social capital acts like an informal insurance in cases of small scale disasters. Social capital is more relevant in this remote study area as it compensates for the gaps in basic infrastructure and proper disaster management institutions. Thus, proper mobilization of social capital can really be an asset to communities living in remote hazardous area

Gender and Rural Poverty in Myanmar: A Micro Level Study in the Dry Zone

The study investigates the poverty incidence, access to resources, and the factors influencing income of both male and female-headed households in the dry zone of Myanmar. A household survey was conducted in six villages with a sample of 220 households in 2003. The Cost of Basic Needs (CBN) method was applied in constructing the absolute poverty line. By applying the absolute poverty line of 252 Kyats per person per day, the female-headed households are more likely to be poor than the male-headed households with or without household size adjustment. Results of the regression analysis revealed that average per capita income of rural households is significantly influenced by 8 independent variables. They are: gender of household head, household size, land holding size, degraded land size, cattle heads, labour force, sources of income, and irrigation water. Moreover, the separate regression analyses were run for male and female-headed households. In addition to the some common significant variables (land, labour, cattle, degraded land, and household size), female-headed households’ income is significantly influenced by training attendance and schooling years of household head. In male-headed households, age of household head, number of income sources and irrigation water are highly linked with the average per capita income. The gender focus rural development strategies should be adopted for promoting the welfare status of both male and femaleheaded households in the dry zone

Fabrication of Light Weight Farms Yoke With The Use of Composite Material

Natural fibers are subdivided based on their origins, coming from plants, animals or minerals. All plant fibers are composed of cellulose while animal fibers consist of proteins (hair, silk, and wool). Plant fibers include bask (or stem or soft sclerenchyma) fibers, leaf or hard fibers, seed, fruit, wood, cereal straw, and other grass fibers. Over the last few years, a number of researchers have been involved in investigating the exploitation of natural fibers as load bearing constituents in composite materials. The use of such materials in composites has increased due to their relative cheapness, ability to recycle and for the fact that they can compete well in terms of strength per weight of material. Natural fibers can be considered as naturally occurring composites consisting mainly of cellulose fibrils embedded in lignin matrix. The cellulose fibrils are aligned along the length of the fiber, which render maximum tensile and flexural strengths, in addition to providing rigidity. The reinforcing efficiency of natural fiber is related to the nature of cellulose and its crystallinity. The existing traditional yoke is made up of the wood of trees like Tun and Haldu which are not easily available in different parts of India. The life of a yoke is about 3 to 5 years, due to this 628 tons of wood is required at every 3-5 years in India that would create a burden to the presently available forests. To overcome these problems, there is a need to develop yoke from waste bio-materials. Keeping this in view, a yoke from composite material was designed and developed and relative comparison between traditional wooden and developed yoke has been done