Bifurcations and Chaos in Time Delayed Piecewise Linear Dynamical Systems

We reinvestigate the dynamical behavior of a first order scalar nonlinear delay differential equation with piecewise linearity and identify several interesting features in the nature of bifurcations and chaos associated with it as a function of the delay time and external forcing parameters. In particular, we point out that the fixed point solution exhibits a stability island in the two parameter space of time delay and strength of nonlinearity. Significant role played by transients in attaining steady state solutions is pointed out. Various routes to chaos and existence of hyperchaos even for low values of time delay which is evidenced by multiple positive Lyapunov exponents are brought out. The study is extended to the case of two coupled systems, one with delay and the other one without delay.Comment: 34 Pages, 14 Figure

Characterization of Natural Fiber Extracted from Sesbania rostrata: An Alternative Potential for Synthetic Fibers

Enriching natural materials is essential for developing eco-friendly composites in structural and automotive applications. The aim of this work is to extensively characterize new natural cellulosic fiber extracted from Sesbania rostrata stem.       S. rostrata fibers (SRFs) show cellulose content of 64.36 % with a range of tensile strength from 156 to 460 MPa and have a low density of 1.365 g/cm3. SRFs has crystallinity index of 58.41%, which is comparable with that of other common natural fibers. Furthermore, SRFs can resist the degradation of cellulose up to 246°C, which is revealed by thermogravimetric analysis.Â

Effect of Potent Ethyl Acetate Fraction of Stereospermum suaveolens Extract in Streptozotocin-Induced Diabetic Rats

To evaluate the antihyperglycemic effect of ethyl acetate fraction of ethanol extract of Stereospermum suaveolens in streptozotocin-(STZ-) induced diabetic rats by acute and subacute models. In this paper, various fractions of ethanol extract of Stereospermum suaveolens were prepared and their effects on blood glucose levels in STZ-induced diabetic rats were studied after a single oral administration (200 mg/kg). Administration of the ethyl acetate fraction at 200 mg/kg once daily for 14 days to STZ-induced diabetic rats was also carried out. The parameters such as the fasting blood glucose, hepatic glycogen content, and pancreatic antioxidant levels were monitored. In the acute study, the ethyl acetate fraction is the most potent in reducing the fasting serum glucose levels of the STZ-induced diabetic rats. The 14-day repeated oral administration of the ethyl acetate fraction significantly reduced the fasting blood glucose and pancreatic TBARS level and significantly increased the liver glycogen, pancreatic superoxide dismutase, and catalase activities as well as reduced glutathione levels. The histopathological studies during the subacute treatment have been shown to ameliorate the STZ-induced histological damage of pancreas. This paper concludes that the ethyl acetate fraction from ethanol extract of Stereospermum suaveolens possesses potent antihyperglycemic and antioxidant properties, thereby substantiating the use of plant in the indigenous system of medicine

Molecular identification of scale insect (Eulecanium giganteum) in Hibiscus rosa-sinensis

Hibiscus rosa-sinensis is a widely grown evergreen valuable medicinal, ornamental species planted in India. Scale insects are small herbivorous insects found on all continents and they are serious sap sucking pests of many ornamental plants. These scale insects are undetectable due to their tiny size, basic morphology, and polyphagous feeding nature. Hence, the management of these tiny insects become a serious concern across the globe. To afford a prospective solution to the problem, an accurate, simple, and developmental-stage-independent identification method is required, hence this study attempted the molecular identification of scale insect in Hibiscus rosa-sinensis using mitochondrial gene Cytochrome Oxidase Subunit I (mtCOI) sequencing. The experiment was carried out by isolating insect DNA using a modified CTAB method. Through two or three rounds of error-prone PCR followed by a steady procedure to amplify a mtCOI region. This region of mtCOI has been used as a standard DNA barcode for a diverse array of taxa. The confirmation has been done by sequencing of mtCOI which suggest the highest similarities with Eulecanium giganteum. This study addresses the questions of biodiversity and molecular characterization of scale insects. Further, the information obtained in this study provides baseline data for future crop improvement programs and integrated pest management strategies

Scaling and synchronization in a ring of diffusively coupled nonlinear oscillators

Chaos synchronization in a ring of diffusively coupled nonlinear oscillators driven by an external identical oscillator is studied. Based on numerical simulations we show that by introducing additional couplings at $(mN_c+1)$-th oscillators in the ring, where $m$ is an integer and $N_c$ is the maximum number of synchronized oscillators in the ring with a single coupling, the maximum number of oscillators that can be synchronized can be increased considerably beyond the limit restricted by size instability. We also demonstrate that there exists an exponential relation between the number of oscillators that can support stable synchronization in the ring with the external drive and the critical coupling strength $\epsilon_c$ with a scaling exponent $\gamma$. The critical coupling strength is calculated by numerically estimating the synchronization error and is also confirmed from the conditional Lyapunov exponents (CLEs) of the coupled systems. We find that the same scaling relation exists for $m$ couplings between the drive and the ring. Further, we have examined the robustness of the synchronous states against Gaussian white noise and found that the synchronization error exhibits a power-law decay as a function of the noise intensity indicating the existence of both noise-enhanced and noise-induced synchronizations depending on the value of the coupling strength $\epsilon$. In addition, we have found that $\epsilon_c$ shows an exponential decay as a function of the number of additional couplings. These results are demonstrated using the paradigmatic models of R\"ossler and Lorenz oscillators.Comment: Accepted for Publication in Physical Review

Make in India – Challenges and Opportunities

Make in India is new national initiative program by government aimed at transforming India into a global manufacturing hub. It includes a slew of proposals aimed at inviting both domestic and foreign companies to invest in India and help it become a manufacturing powerhouse. “ZERO DEFECT AND ZERO EFFECT”slogan was defined by our prime minister Narendera Modi, as part of Make in India programme which handle innovative processes materials, enhance skill development,technologies and the manufacturing mechanism is guided to make the goods that are defect free and have no negative environmental or ecological effects. Main mission of this project is to make the production India and sell the products all over the world. The primary focus of "Make in India" project is to enhance the annual growth rate of 25 sectors from 12-14 % to improve GDP rate and to create 100 million job opportunities within 2022. The purpose of this study is to explain the concept of Make in India campaign, its importance, schemes,and its impact on Indian economy. This paper also proposes to identify the challenges and opportunities as well as recommended possible solutions to deal with the same

Dyeing of cotton with reactive dyes using pre-treated sea water

The present study explores the use of sea water as dyeing medium for cotton textiles with reactive dyes. Sea water has been pre-treated with calcium oxide/sodium carbonate to remove calcium and magnesium ions. The findings show that the addition of 20 g/L of sodium chloride is required to increase the exhaustion of dye in pre-treated sea water instead of 60 g/L of sodium chloride as required in conventional dyeing method. SEM , KESF and EDAX analyses show no significant difference on the surface of pre-treated sea water dyed and conventional dyed fabrics. It is also found that there is no significant difference in the wash and light fastness properties between pre-treated sea water dyed fabrics and conventional dyed fabrics. The developed process is in the direction of addressing sustainability issues of textile processing industries.

Dyeing of cotton with reactive dyes using pre-treated sea water

319-325The present study explores the use of sea water as dyeing medium for cotton textiles with reactive dyes. Sea water has been pre-treated with calcium oxide/sodium carbonate to remove calcium and magnesium ions. The findings show that the addition of 20 g/L of sodium chloride is required to increase the exhaustion of dye in pre-treated sea water instead of 60 g/L of sodium chloride as required in conventional dyeing method. SEM , KESF and EDAX analyses show no significant difference on the surface of pre-treated sea water dyed and conventional dyed fabrics. It is also found that there is no significant difference in the wash and light fastness properties between pre-treated sea water dyed fabrics and conventional dyed fabrics. The developed process is in the direction of addressing sustainability issues of textile processing industries

Cotton based bioactive wound dressing material with high absorbency and antibacterial activity

63-68Cotton gauze fabrics with improved absorbency through yarn twist optimization and antimicrobial property using nanosilver have been prepared. The absorbency, mass loss (%), dehydration rate, wicking rate, surface morphology, surface chemical nature and antibacterial activity of cotton gauze fabrics have been evaluated. The gauze fabric with low twisted yarn shows better absorbency and vertical wicking rate as compared to that with higher twisted yarn. The cotton gauze fabric with optimized twist multiplier (3.0 TM) is then treated with silver nitrate precursor to form in-situ nanosilver on the surface of cotton by applying elevated pressure and temperature. The surface morphology has been studied by SEM and chemical nature by FTIR. The in-situ technique produces an average nanosilver particle size of 120 ± 48 nm and shows 100% reduction for Klebsiella pneumoniae (Gram-negative bacterium) and 99.99% for Staphylococcus aureus (Gram-positive bacterium)

Cotton based bioactive wound dressing material with high absorbency and antibacterial activity

Cotton gauze fabrics with improved absorbency through yarn twist optimization and antimicrobial property using nanosilver have been prepared. The absorbency, mass loss (%), dehydration rate, wicking rate, surface morphology, surface chemical nature and antibacterial activity of cotton gauze fabrics have been evaluated. The gauze fabric with low twisted yarn shows better absorbency and vertical wicking rate as compared to that with higher twisted yarn. The cotton gauze fabric with optimized twist multiplier (3.0 TM) is then treated with silver nitrate precursor to form in-situ nanosilver on the surface of cotton by applying elevated pressure and temperature. The surface morphology has been studied by SEM and chemical nature by FTIR. The in-situ technique produces an average nanosilver particle size of 120 ± 48 nm and shows 100% reduction for Klebsiella pneumoniae (Gram-negative bacterium) and 99.99% for Staphylococcus aureus (Gram-positive bacterium