Characterization of new cellulosic fiber from the stem of Sida rhombifolia

Natural fibers play a vital role in the field of composites mainly due to their environmental friendliness, the nature of their disposal, and low energy requirement for processing. Recently, research ideas have focused on exploration of promising natural fibers with superior mechanical properties. Sida rhombifolia is one such perennial shrub from which high stiffness natural fibers can be extracted. The physico-chemical properties of Sida rhombifolia fibers (SRFs), crystallinity index (56.6%), higher cellulose (75.09 wt.%) content, and lower density (1320.7 kg/m³) were revealed and compared to those properties of other natural fibers.     

A coarse-grained explicit solvent simulation of rheology of colloidal suspensions

We use a simple extension of the dissipative particle dynamics (DPD) model to address the dynamical properties of macrosolutes immersed in complex fluid solvents. In this approach, the solvent particles are still represented as DPD particles, thereby retaining the time and length scale advantages offered by the DPD approach. In contrast, the solute particles are represented as hard particles of the appropriate size. We examine the applicability of this simulation approach to reproduce the correct hydrodynamical characteristics of the mixture. Our results focus on the equilibrium dynamics and the steady-state shear rheological behaviors for a range of volume fractions of the suspension, and demonstrate excellent agreement with many published experimental and theoretical results. Moreover, we are also able to track the glass transition of our suspension and the associated dynamical signatures in both the diffusivities and the rheological properties of our suspension. Our results suggest that the simulation approach can be used as a one-parameter model to examine quantitatively the rheological properties of colloidal suspensions in complex fluid solvents such as polymeric melts and solutions, as well as allied dynamical phenomena such as phase ordering in mixtures of block copolymers and particles.     

Fourier transform Infrared characterization of melanin free ink from selected cephalopods for identification of active functional groups responsible for antioxidant activity

The present investigation aims to explore the active functional groups that are responsible for the antioxidant property in MFI from three cephalopods such as Sepia pharaonis (CMFI), Sepioteuthis lessioniana (SMFI) and Amphioctopus aegina (OMFI) using Fourier Transform Infrared (FTIR) spectroscopy. Highest DPPH scavenging activity of 28.29 ± 0.41% and metal chelating activity of 47.62 ± 0.48% were shown by MFI from A. aegina (OMFI) at a concentration of 0.045 mg/ml and 0.04 mg/ml, respectively. Though the invitro antioxidant values of MFI were low, when added with sardine fish mince, it retarded the lipid oxidation during the entire storage period and it was very clear with the lower TBARS values compared to the control. FTIR analysis of CMFI, SMFI and OMFI revealed the presence of characteristic strong band at 3361.92 cm^?1, 3364.54 cm^?1 and 3373.96 cm^?1 and at 1642.20 cm^?1, 1636.21 cm^?1and 1635.53 cm^?1,respectively. The O–H and N–H stretching vibrations and alkenyl c = c stretch corresponding to the two vibrations in all the three spectra can be accountable for its antioxidant activities leading to its wide new applications as a natural antioxidant from marine resources.     

Antimony(III) Halide-Assisted Stereospecific Coordination of Thione

The antimony halide-aided stereospecific coordination of a cyclic thiourea-type of ligand is observed for the first time. The antimony(III) imidazole thione complexes syn-[( L¹ )SbCl₃] ( syn- 1 ) and anti-[( L¹ )SbBr₃] ( anti- 2 ) have been synthesized in very good yield by the reaction between the spatially defined steric impact ligand [(IPaul)S] ( L¹ ) ([(IPaul)S]=1,3-bis(2,4-methyl-6-diphenyl phenyl)imidazole thione) and corresponding antimony halide. The stereoselective formation of complexes syn- 1 and anti- 2 has been confirmed by both NMR and single-crystal X-ray diffraction studies. Interestingly the stereospecific nature of syn- 1 and anti- 2 remains intact in solution. Furthermore, the thermal stability of antimony(III) imidazole thione complexes were examined by TGA analysis.     

Mixing in Hypervelocity Flows

This study considers analysis of data obtained from tests witha generic combustor model at the pulse facility T5 located in theGraduate Aeronautical Laboratories at California Institute of Technology(GALCIT). Comparisons were made between the flow predictions usingBaldwin–Lomas and k–epsilon turbulence models. Computedpredictions of mixing efficiency, wall pressure signatures, eddyviscosity distributions, etc., obtained from both the turbulence modelswere similar. Computed wall pressure distributions agreed with thosefrom experiments. Spatial uniformity of the injectant-test gas mixturewas considered. Based on the results obtained, use of the Baldwin–Lomaxturbulence model can be considered to be sufficient for the conditionsconsidered, as it yields adequate predictions with significant savingsin computational costs.     

Dense energetic compounds of carbon,hydrogen, nitrogen,and oxygen atoms. V. 1,2,7,8-bisfuroxano-3,4,9,10-tetranitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]benzotriazole (BTBB)

A reaction between 2, 8-dichloro-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]-benzotriazole 8 and sodium azide in dimethyl sulfoxide produced 3, 9-diazido-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo [2, 1-a]benzotriazole 10 rather than the 2.8-diazido isomer 9 expected by direct displacement. Thermolytic elimination of nitrogen (2 moles) converted the dinitro diazide 10 to 3,4,9,10-bisfuroxano-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]benzotriazole 11 that was subsequently nitrated to give the 2,8-dinitro derivative 12 . Similar nitration converted the dinitro diazide 9 to the trinitro 15 and tetranitro 14 derivatives: thermolysis of the latter gave 1,2,7,8-bisfuroxano-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]-benzotriazole 16 . Nitration (100% HNO₃, CF₃SO₃H) converted compound 16 to the 3,4,10-trinitro derivative 17 , whereas a similar nitration (100% HNO₃, FSO₃H) gave the title compound BTBB, an insensitive high-energy, high-density (d 2.03 g/cc) molecule. © 1995 John Wiley & Sons, Inc.     

Pressure Dependence of the Electromechanical and Vibrational Properties of Pentaerythritol

The elastic, piezoelectric and dielectric constants of pentaerythritol, C (CH₂OH)₄, (PET) have been computed as a function of pressure employing the structural data of KATRUSIAK and the lattice dynamical model of RAMAMOORTHY and KRISHNAMURTHY. Using these electromechanical constants, the Young's modulus, the linear compressibility, the bulk modulus and the acoustic wave velocities are computed for various high pressures. The pressure dependence of the vibration spectrum of PET using rigid and non‐rigid lattice models is also obtained. The anomalous variation of these electromechanical and other physical quantities predict the most probable pressure for phase transition in PET to be around 280 MPa. The mechanism of the transition and the variation in the physical behaviour accompanying the transition are discussed.