A novel formulation of the sodium lignin sulfonate (SLS) bio based branched chain lignin polymer modified with the sulfonic acid and the pomegranate rind extract (PRE), a wastage plant biomolecule, ...has been applied to the cellulosic cotton fabric to make it flame retardant. It was found that the control, 10% SLS and the PRE treated cotton fabric showed the limiting oxygen index (LOI) value of 18, 25, and 24, respectively and completely burnt within one to two minutes in the vertical flammability test. On the contrary, (PRE+ 10% SLS) treated cotton fabric showed 32% add-on and the LOI value of 32 with the specific char length of 40 mm after the completion of the vertical flammability test as per IS1871 method A. Extent of the afterglow duration and the char length, both have been decreased with increasing the percentage concentration of the SLS 5 to 10% (W/V) into the PRE mixture. Thermo-gravimetry (TG) analysis of the control, PRE and the 10% SLS treated cotton fabric showed only 10% remaining char mass at 450°C in air atmosphere whereas the (PRE+ 10% SLS) treated fabric showed much lower mass loss rate and 45% remaining char mass at the said temperature. Moreover, the char morphology of the (PRE+ 10% SLS) formulation treated fabric showed structural integrity (weave of the fabric) with the presence of the small bubbles after the completion of the combustion phenomena. Mechanism of the fire retardancy revealed the fact that during the treatment, nitrogen containing alkaloids, long chain carbon molecule, poly phenolic compounds (present in the PRE) and the sulfur containing sulfonate groups, polyphenolic compounds (present in the SLS) deposited on the cotton fabric surface, combinedly acted on the flame retardancy (to arrest the both flame and the afterglow) and the char formation of the underlying cellulose structure, during burning. Moreover, the detail color values of the control and the treated fabrics also have been elucidated in the present research context.
For the first time, a mixed formulation of the sodium tri-polyphosphate (STPP) and the pomegranate rind extract (PRE) has been imparted to the cotton fabric to make it flame-retardant. It was found ...that the control, 3% STPP and PRE-treated cotton fabric showed the limiting oxygen index (LOI) value of 18, 21 and 26%, respectively, and completely burnt within 80, 120 and 420 s, respectively, in the vertical flammability test. On the contrary, (PRE + 2% STPP)-treated cotton fabric showed the LOI value of 35% with a specific char length of 30 mm. Thermo-gravimetric analysis of the control, PRE- and the 3% STPP-treated cotton fabric showed only 1–2% remaining char mass at 550 °C, whereas the (PRE + 3% STPP)-treated fabric registered the char mass retention of more than 10% at the said temperature. Cone calorimetric data showed that the peak heat release rate for the treated fabric has been reduced dramatically compared to the heat release value of the control cotton fabric.
Graphical abstract
We estimate cosmic microwave background (CMB) polarization power spectra and temperature-polarization cross-spectra, from the 9-year data of the Wilkinson Microwave Anisotropy Probe (WMAP). ...Foreground cleaning is implemented using minimum variance linear combinations of the coefficients of needlet decompositions of sky maps for all WMAP channels, to produce maps for CMB temperature anisotropies (T-mode) and polarization (E and B-modes), for nine different years of observation. The final power spectra are computed from averages of all possible cross-year power spectra obtained using foreground-cleaned maps for the different years. Our analysis technique yields a measurement of the EE spectrum that is in excellent agreement with theoretical expectations from the current cosmological model. By comparison, the publicly available WMAP
EE power spectrum is higher on average (and significantly higher than the predicted EE spectrum from the current best fit) at scales larger than about a degree, an excess that is not confirmed by our analysis. Our TE and TB measurements are in good agreement overall with the WMAP ones and are compatible with the theoretical expectations, although a few data points are off by a few standard deviations, and yield a reduced χ2 somewhat above expectation. As predicted for a standard cosmological model with low tensor-to-scalar ratio, the EB and BB power spectra obtained in our analysis are compatible with zero.
•Tannin based flame retardancy occupying a major field in the field of sustainable flame retardancy of polymeric materials.•Tannin based polyphenols of different wastage plant extracts responsible ...for flame retardancy of natural and synthetic polymers.•Mechanism of flame retardancy exhibited condensed phase behavior of flame retardant action.•Thermo-gravimetric behavior of tannin treated polymers showed catalyzation of pyrolysis and high char retention.
Sustainable flame retardancy of polymeric materials is one of the thirsty, promising and challenging areas in today's fire safety world. Different researchers are trying to achieve that scientific beauty employing different research perspectives. Bio-based (bio-macromolecule) flame retardancy is one of the emerging and promising fields and continuously adding feathers in the crown of sustainable flame retardancy from the past decade. Bio-based flame retardants are sustainable. Tannin is an aromatic polyphenolic compound, one of the important and major active ingredients of most of the plant-based bio-macromolecules. As per reported documents, past few years have witnessed great flame retardancy potential of tannin and tannin based plant bio-macromolecules on textile, steel and other natural and synthetic polymeric materials. However, till date, no critical review has been registered on the compilation of the flame retardant performance of tannin and tannin based plant bio-macromolecule treated natural and synthetic textiles, polymeric substrates etc, This review report critically elucidates the thermal properties of tannic acid and in detail flame retardant performances of tannic acid (hydrolyzed and condensed), chemically modified tannic acid-treated textile, polymeric substrates. Besides, the review context also registers the mechanism involved behind the tannin based flame retardancy of different natural and synthetic polymeric substrates like cotton, wool, silk, epoxy resin, steel, polyester, nylon etc. Besides, some futuristic scientific suggestions and challenges also have been systematically discussed at the end part of this review manuscript.
•Degum liquor of ramie fibre, a purely wastage product has been explored for coating on the polyester fabric.•Treated fabric showed LOI value of 27 and also addressed the dangerous melt dripping ...phenomenon of the synthetic polymer.•Treated polyester fabric showed high char mass retention and lower rate of weight degradation.•Physical properties of the treated fabric also remain unchanged after completion of the treatment.•Pectin, lignin, hemicellulose, tannin present in the degum liquor responsible for flame retardancy action of polyester.
Decorticated ramie fibre has been degummed with alkali based formulation and the wastage degummed liquor has been applied on the polyester fabric at different concentrations by following padding technique. Degummed liquor has been characterized by using Liquid chromatography mass spectroscopy (LCMS), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo-gravimetry (TG) analysis to understand the major chemical groups present in it and its thermal behavior. Chromatography results revealed the presence of different polyphenols, pectin, tannin based compound in the degum liquor. TG curve of degum liquor reveals almost 50% mass retention at 500°C. Treated polyester fabric showed almost 40% more limiting oxygen index (LOI) as compared to the control fabric. In addition of it, melt dripping property of the treated polyester fabric also has been stopped with lower shrinkage during combustion. TG analysis of the said fabric showed 20–25% more char mass retention and lower rate of weight loss as compared to the control one. Char morphology of the control and the treated fabric was also examined and analyzed in detail. Besides, a mechanism lies behind the flame retardancy of the polyester fabric also has been postulated with the composition of the chemical compound present in the wastage liquor. It was found that high molecular weight phenolic components, pectin, natural coloring matter, tannin based polyphenols etc. present in the degum liquor playing a major role behind thermal stability. Lastly, tensile and physical properties of the treated fabric also have been measured and analytically compared with the untreated polyester.
Abstract
Uniaxial random field disorder induces a spontaneous transverse magnetization in the XY model. Adding a rotating driving field, we find a critical point attached to the number of driving ...cycles needed to complete a limit cycle, the first discovery of this phenomenon in a magnetic system. Near the critical drive, time crystal behavior emerges, in which the period of the limit cycles becomes an integer
n
> 1 multiple of the driving period. The period
n
can be engineered via specific disorder patterns. Because
n
generically increases with system size, the resulting period multiplication cascade is reminiscent of that occurring in amorphous solids subject to oscillatory shear near the onset of plastic deformation, and of the period bifurcation cascade near the onset of chaos in nonlinear systems, suggesting it is part of a larger class of phenomena in transitions of dynamical systems. Applications include magnets, electron nematics, and quantum gases.
Histone deacetylases (HDACs) are frequently overexpressed in broad range of cancer types, where they alter cellular epigenetic programming to promote cell proliferation and survival. However, the ...mechanism by which HDACs become overexpressed in human cancers remains somewhat of a mystery. In this study, we investigated the expression and functional significance of miR-449a in prostate cancer cells. Using real-time PCR, we found that miR-449a is downregulated in prostate cancer tissues relative to patient-matched control tissue. Introduction of miR-449a into PC-3 prostate cancer cells resulted in cell-cycle arrest, apoptosis and a senescent-like phenotype. In silico analysis of 3'-UTR regions identified a number of genes involved in cell-cycle regulation as putative targets of miR-449a. Using a luciferase 3'-UTR reporter system, we established that HDAC-1 (histone deacetylase 1), a gene that is frequently overexpressed in many types of cancer, is a direct target of miR-449a. Further, our data indicate that miR-449a regulates cell growth and viability in part by repressing the expression of HDAC-1 in prostate cancer cells. Our findings provide new insight into the function of miRNA in regulating HDAC expression in normal versus cancerous tissue.
We present a lattice calculation of the electromagnetic (EM) effects on the masses of light pseudoscalar mesons. The simulations employ 2+1 dynamical flavors of asqtad QCD quarks and quenched ...photons. Lattice spacings vary from ≈0.12 fm to ≈0.045 fm. We compute the quantity ε, which parametrizes the corrections to Dashen’s theorem for the K+–K0 EM mass splitting, as well as εK0, which parametrizes the EM contribution to the mass of the K0 itself. An extension of the nonperturbative EM renormalization scheme introduced by the BMW group is used in separating EM effects from isospin-violating quark mass effects. We correct for leading finite-volume effects in our realization of lattice electrodynamics in chiral perturbation theory, and remaining finite-volume errors are relatively small. While electroquenched effects are under control for ε, they are estimated only qualitatively for εK0 and constitute one of the largest sources of uncertainty for that quantity. We find ε=0.78(1)stat(+8−11)syst and εK0=0.035(3)stat(20)syst. We then use these results on 2+1+1 flavor pure QCD highly improved staggered quark (HISQ) ensembles and find mu/md=0.4529(48)stat(+150−67)syst.
A new mechano-chemical formulation is developed for making flame resistant sisal fibre rope with low chemical loading. Sisal yarn is treated with a different formulation of ammonium sulfamate (AS) ...(50 g/L and 100 g/L) by following dip-dry approach at room temperature. Limiting oxygen index (LOI) measures the minimum amount of oxygen required in the mixture of nitrogen and oxygen for burning of the sample. Treated sisal showed LOI values of 28–32 and self-extinguishment in vertical flammability test whereas control sisal yarn showed LOI value of 21 and burnt easily within a minute. Forced combustion results revealed that AS treated sisal yarn exhibited 50% lower peak heat release rate (PHRR) than the control sisal yarn. Sisal yarn based rope was prepared by following braiding technique with three single yarns, using different combinations of untreated and treated sisal yarn. Fire retardant sheath yarn is used to cover the untreated sisal yarn present in the core by twisting or braiding. Rope made from sisal yarn has shown LOI value 30–40. Besides, a new method of simultaneous dyeing and flame retardant finishing of sisal rope is also proposed. The physical properties of the ropes were measured and it was found that the extent of strength loss is statistically insignificant at 95% confidence level. The thermal stability of the AS-treated sisal yarn is measured by thermo-gravimetric analysis. Charring behaviour of the control and AS treated sisal fibre was examined using microscopic images and scanning electron microscopy. Besides, in detail mechanism behind flame retardancy is revealed in the context with the help of XRD and FTIR analysis techniques.
Graphical Abstract
We study interference patterns of a magnetically doped topological insulator Bi(2-x)Fe(x)Te(3+d) by using Fourier transform scanning tunneling spectroscopy and observe several new scattering ...channels. A comparison with angle-resolved photoemission spectroscopy allows us to unambiguously ascertain the momentum-space origin of distinct dispersing channels along high-symmetry directions and identify those originating from time-reversal symmetry breaking. Our analysis also reveals that the surface state survives far above the energy where angle-resolved photoemission spectroscopy finds the onset of continuum bulk bands.
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