Constraints on light Dark Matter fermions from relic density consideration and Tsallis statistics

The cold dark matter fermions with mass MeV scale, pair produced inside the supernova SN1987A core, can freely stream away from the supernovae and hence contributes to its energy loss rate. Similar type of DM fermions(having similar kind of coupling to the standard model photon), produced from some other sources earlier, could have contributed to the relic density of the Universe. Working in a theory with an effective dark matter-photon coupling (inversely proportional to the scale $\Lambda$) in the formalism of Tsallis statistics, we find the dark matter contribution to the relic density and obtain a upper bound on $\Lambda$ using the experimental bound on the relic density for cold non-baryonic matter i.e. $\Omega h^2 = 0.1186 \pm 0.0020$. The upper bound obtained from the relic density is shown with the lower bound obtained from the Raffelt's criterion on the emissibity rate of the supernovae SN1987A energy loss $\dot{\varepsilon}(e^+ e^- \to \chi \overline{\chi}) \le 10^{19}~\rm{erg~g^{-1}s^{-1}}$ and the optical depth criteria on the free streaming of the dark matter fermion (produced inside the supernovae core). As the deformation parameter $q$ changes from $1.0$ (undeformed scenario) to $1.1$(deformed scenario), the relic density bound on $\Lambda$ is found to vary from $\sim 4.9 \times 10^7$ TeV to $1.6 \times 10^8$ TeV for a fermion dark matter($\chi$) of mass $m_\chi = 30~\rm{MeV}$, which is almost $10$ times more than the lower bound obtained from the SN1987A energy loss rate and the optical depth criteria. \noindent {{\bf Keywords}: Dark matter, Relic density, Supernova cooling, Tsallis statistics, free-streaming, } }Comment: 18 Pages, 10 figure

Bio-based composites from bagasse using carbohydrate enriched cross-bonding mechanism: A formaldehyde-free approach

In this study, cross-bonded self-binding and bone glue-bonded particleboards were manufactured from sugarcane (Saccharum officinarum L.) bagasse with different pre-treatments of particles. Six types of panels were manufactured from bagasse particles with and without bone glue. The physical, mechanical, and thermal properties of the panels were examined according to the standards. Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TG) were performed to investigate the changes in the chemical bonds and thermal stability of the fabricated composites, respectively. It was found that cross-bonded bagasse self-binding (TC) and bone glue-bonded (T3) panels fabricated from non-boiled bagasse particles showed higher physical and mechanical properties compared to the other types of panels. Non-boiled bagasse particles with bone glue panels showed the highest mechanical properties, i.e., modulus of rupture (MOR = 26.22 MPa), modulus of elasticity (MOE = 4302 MPa), tensile strength = 8.35 MPa, and hardness = 1.72 MPa. TC and T3 panels also showed higher thermal stability compared to the other types of panels. A new peak at 3331-3334 cm-1 for the N-H stretching vibration in the FTIR analysis represents the presence of bone glue in the cross-bonded particleboards. Thus, this research advances the production of formaldehyde-free bagasse particleboard, introducing the cross-bonding technique and sustainable bone glue

Scientometric study of books authored by Nobel laureate Amartya Sen

The paper presents the scientometric portrait of Bharat Ratna Amartya Sen, also a Nobel laureate in Economic Sciences, based on the books published by him. During the period 1960-2015, Sen produced 43 books either singly or collaboratively. Jean Dreze is Sen’s most prominent collaborator. The highest number of books (27.92%) was published during 2000-2009. Although most of his books were published in English, a number of his books have been translated into several Indian and foreign languages. Most of his books (20.94%) are on social problems, followed by politics and government (13.95%) and financial economics (11.63%)