Analysis of impact energy absorption of kevlar and polyester composite impregnated with corn starch shear thickening fluid

Kevlar and polyester (PET) composite structures have been developed through layering by impregnation with optimizedcorn starch shear thickening fluid (CS−STF), prepared using corn starch (CS) and polyethylene glycol (PEG). Corn starchhas been characterized for particle size and distribution through dynamic light scattering. The CS and PEG ratio (40:60,46:54, 52:48 and 58:42) has been studied through fluidity and shear thickening measurements using in-house funnelcollector and electro-mechanical shearing stirrer through ampere measurement studies respectively. Based on the establishedimpact energy calibration curve and energy calculations, the impact energy absorption of CS−STF impregnated fibrecomposites have been studied. The order of layering of the STF in impregnated textile structures has been systematicallystudied for effective impact energy absorption. Shearing studies reveal that at and above shearing time of 3000 μs, shearthickening is found to be prominent for the optimum CS: PEG ratio of 52: 48. Similar trend is also observed in the impactenergy absorption studies of textile structures impregnated with the CS−STF. One layer of kevlar woven fabric followed byone or more layers of PET nonwovens with CS−STF show good performance in impact energy absorption. Similar trend isalso observed in 6, 5 and 4 kevlar layering. It is observed that the presence of more than one layer of kevlar on the top of thenonwovens in the composite does not contribute; rather it decreases the energy absorption. The treated structures show100 % antimicrobial activity by AATCC 100 method and they do not develop smell, while the untreated samples developmicrobes with intense smell

Analysis of impact energy absorption of kevlar and polyester composite impregnated with corn starch shear thickening fluid

80-89Kevlar and polyester (PET) composite structures have been developed through layering by impregnation with optimized corn starch shear thickening fluid (CS−STF), prepared using corn starch (CS) and polyethylene glycol (PEG). Corn starch has been characterized for particle size and distribution through dynamic light scattering. The CS and PEG ratio (40:60, 46:54, 52:48 and 58:42) has been studied through fluidity and shear thickening measurements using in-house funnel collector and electro-mechanical shearing stirrer through ampere measurement studies respectively. Based on the established impact energy calibration curve and energy calculations, the impact energy absorption of CS−STF impregnated fibre composites have been studied. The order of layering of the STF in impregnated textile structures has been systematically studied for effective impact energy absorption. Shearing studies reveal that at and above shearing time of 3000 µs, shear thickening is found to be prominent for the optimum CS: PEG ratio of 52: 48. Similar trend is also observed in the impact energy absorption studies of textile structures impregnated with the CS−STF. One layer of kevlar woven fabric followed by one or more layers of PET nonwovens with CS−STF show good performance in impact energy absorption. Similar trend is also observed in 6, 5 and 4 kevlar layering. It is observed that the presence of more than one layer of kevlar on the top of the nonwovens in the composite does not contribute; rather it decreases the energy absorption. The treated structures show 100 % antimicrobial activity by AATCC 100 method and they do not develop smell, while the untreated samples develop microbes with intense smell

Analysis of block vibrations induced by combustion chamber pressure in a diesel engine

The paper describes an experimental methodology devised to study engine block displacement of internal combustion engine in the radial direction due to combustion force. This force produced in the cylinder varies with the chamber profile since flow parameters are influenced by the combustion chamber profile. Combustion effectiveness fluctuates depending upon flow parameters. To correlate between combustion and injection and to detect faults in the injection system it is necessary to supervise the combustion in the individual cylinders. This can be accomplished by evaluating the crankshaft speed at the flywheel. Speed is directly related to combustion by means of indicated pressure and torque. Different combustion chamber profiles were taken for the analysis along with speed and load as the design variables. The displacement and time-domain frequency for all the profiles were compared. The results provide displacement induced by the combustion pressure, uncertainty in combustion processes and nonlinear vibration of the engine block. This new approach in engine parameter design gives insight on the vibrational processes in the case of different chamber profiles as well as sources of noise in the diesel engine

Structure models for the hydrated and dehydrated nitrate-intercalated layered double hydroxide of Li and Al

Imbibition of LiNO3 into gibbsite results in the formation of a single phase layered double hydroxide of the composition LiAl2(OH)6(NO3)·1.2H2O. This phase undergoes reversible dehydration along with the compression of the basal spacing accompanied by the reorientation of the nitrate in the interlayer gallery. The hydrated phase is a solid solution of two lattices: (i) a hexagonal lattice defining the ordering of atoms within the metal hydroxide layer, and (ii) a lattice of orthorhombic symmetry defining the ordering of atoms within the interlayer. DFT calculations of the hydration behaviour show that there is no registry between the two sublattices. In the dehydrated phase, the nitrate ion is intercalated with its molecular plane parallel to the metal hydroxide layer and the crystal adopts a structure of hexagonal symmetry

Density functional theoretical studies on photoswitching and charge migration dynamics of thio and selenoureidopeptides

Density functional theoretical calculations have been performed to investigate the changes in electronic structure at ground and excited states of ureidopeptides on substitution with higher chalcogens like sulphur and selenium for oxygen. This replacement results in a reduced preference towards the intramolecular hydrogen bonding interaction, thus linear conformers are found to be stable at both states. Nevertheless, conformational switching observed during this process is mainly due to n to �* transition that leads to the dihedral angle � change from trans to cis with a rotational barrier of 10 to 17 kcal mol-1. The computed barrier is lesser than that reported for oxopeptides (20 kcal mol-1). And, the hole migration dynamics after immediate ionization illustrates that the hole originated at ureido end evolves in time (2�4 fs) while the hole generated at the carboxylate end will not evolve as reported for ureidopeptides. The usage of these candidates as photoswitches has also been explored. Copyright © 2017 John Wiley & Sons, Ltd

Isolation and characterization of anticoagulant compound from marine mollusc Donax faba (Gmelin, 1791) from Thazhanguda, Southeast Coast of India

Glycosaminoglycans (GAGs) are linear polysaccharides found in the extracellular matrix and biological fluids of animals where they interact with hundreds of proteins and perform a variety of critical roles. There are five classes of animal GAGs: heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), keratan sulfate (KS) and hyaluronan (HA). Many biological functions can be monitored directly by their impact on GAG quantity. In the present study, glycosaminoglycans were isolated from marine bivalve Donax faba. The amount of crude GAG was estimated as 12 gm/kg and of tissue in D. faba. After purification using gel  chromatography, the yield was found to be 0.83 mg/kg. The bivalve showed the anticoagulant activity of the crude and purified samples 58 and 114 USP units/mg correspondingly in D. faba. The structural characterization of anticoagulant GAG was analyzed by Fourier transform infrared spectroscopy. Among the marine bivalve, D. faba purified showed more anticoagulant activity than that of crude sample. The results of this study suggest that the GAG from D. faba could be an alternative source of heparin.Keywords: Donax faba, GAGs crude and purified, anticoagulant activity, Fourier transform- infra red (FTIR).African Journal of Biotechnology Vol. 12(40), pp. 5968-597

Association between schizophrenia polygenic risk and neural correlates of emotion perception.

The neural correlates of emotion perception have been shown to be significantly altered in schizophrenia (SCZ) patients as well as their healthy relatives, possibly reflecting genetic susceptibility to the disease. The aim of the study was to investigate the association between SCZ polygenic risk and brain activity whilst testing perception of multisensory, dynamic emotional stimuli. We created SCZ polygenic risk scores (PRS) for a sample of twenty-eight healthy individuals. The PRS was based on data from the Psychiatric Genomics Consortium and was used as a regressor score in the neuroimaging analysis. The results of a multivariate brain-behaviour analysis show that higher SCZ PRS are related to increased activity in brain regions critical for emotion during the perception of threatening (angry) emotions. These results suggest that individuals with higher SCZ PRS over-activate the neural correlates underlying emotion during perception of threat, perhaps due to an increased experience of fear or neural inefficiency in emotion-regulation areas. Moreover, over-recruitment of emotion regulation regions might function as a compensation to maintain normal emotion regulation during threat perception. If replicated in larger studies, these findings may have important implications for understanding the neurophysiological biomarkers relevant in SCZ

DIELECTRIC RELAXATION STUDIES OF AMIDES WITH 2-METHOXYETHANOL AND 2- BUTOXYETHANOL USING TIME DOMAIN REFLECTOMETRY TECHNIQUE

ABSTRACT Complex dielectric permittivity measurements of amides like Formamide (FA), N-methylformamide (NMF) and N,N-dimethylformamide (DMF) with alcohols such as 2-methoxyethanol (2-ME) and 2-butoxyethanol (2-BE) has been carried out at different concentration in the frequency range of 10MHz to 30GHz using Time Domain Reflectometry (TDR). The least squares fit method has been used to obtain the static dielectric constant (ε 0 ), relaxation time (τ) and Bruggeman factor (f B ) for binary mixtures. The Bruggeman plot shows a deviation from linearity. This deviation was attributed to some sort of molecular interaction which may take place between the unlike molecules. The effective Kirkwood correlation factor (g eff ) and corrective Kirkwood correlation factor (g f ) of the mixtures have been determined and discussed to yield information on the structure and dynamics of the mixtures and it confirms the structural formation due to intermolecular interaction between amides with 2-ME and 2-BE. The relaxation time is increasing with increasing chain length of alcohols and is decreasing with increasing amide concentration. The excess static dielectric constant (ε E ) and excess inverse relaxation time (1/τ) E values are indicates that is a form of hydrogen bonding interaction between the 2-ME and 2-BE with amides systems, for all the mixtures dipoles are slowly rotated. The free energy of activation for relaxation time (ΔF τ ) is greater for initial concentration in all the system studied

Association of fibroblast growth factor 21 with oxidative stress and lipid profile in type 2 diabetes

Background: Cardiovascular disease is the most prevalent cause of morbidity and mortality in diabetic patients. Fibroblast growth factor 21 (FBG 21) is an endocrine factor that regulates glucose and lipid metabolism, insulin resistance, and obesity. Blood levels of FGF21 are elevated in patients with atherosclerosis, macrovascular, and microvascular complications of diabetes, possibly due to a compensatory up regulation. Studies reported that FGF21 is an important regulator of mitochondrial and oxidative stress. The role of FGF21 in chronic diseases and the diminished oxidative stress observed with anti-diabetic therapy has been the target of new studies. Current study aimed to evaluate serum FGF21 levels and its association with oxidative stress and lipid profile levels in type 2 diabetic patients.Methods: 100 controls and 100 diabetic patients on oral hypoglycemic drugs between 35-55 years of age without any cardiac, renal, liver, and thyroid dysfunction were selected for this study. Oxidative stress (MDA), total antioxidant status (FRAP), and FGF21 were measured. FGF21 was analyzed by ELISA methods. Serum MDA was assessed by the method of Yagi  serum total antioxidant status was measured by the method of Benzie et al.Results: FGF21 level was increased in diabetic patients compared with controls. There was a significant positive correlation of FGF21 with MDA (r=0.875, p<0.01) and negative correlation with FRAP observed (r= -0.867 p<0.01). There was also positive correlation of FGF21 with total cholesterol (r=0.499, p<0.01), triglycerides (r=0.648, p<0.01), LDL-cholesterol (r=0.337, p<0.01) and negative correlation with HDL-cholesterol (r= -0.172, p<0.05) were observed.Conclusions: Increased oxidative stress and decreased antioxidant status were observed in diabetics. This could be due to dyslipidemia and increased generation of free radicals. High levels of FGF21 observed in our study might represent its resistant state and the compensatory response to maintain metabolic homeostasis. Further studies are needed to explore the role of FGF21 as a novel marker in predicting cardiovascular risk in diabetic patients