Experimental Characterisation of GLass Aluminum REinforced (GLARE™) laminates

Fibre metal laminates such as GLARE™ have found promising application in the aerospace industry. These laminates were developed at the structures and materials laboratory of Delft University of Technology, Netherlands. GLARE™ is a material belonging to the family of Fibre Metal Laminates consisting of thin aluminum layers bonded with unidirectional S2-Glass fibres with an adhesive. Aluminum and S2-Glass when combined as a hybrid material can provide best features of the both metals and composites. These materials have excellent fatigue, impact and damage tolerance characteristics and a lower density compared to aluminum. GLARE™ has found major application in front and aft upper fuselage, leading edges of empennages of advanced civil aircrafts like A380. This document looks into the evaluation of two configuration of GLARE™ for its mechanical and impact characteristics. The mechanical characterisation was carried out for tensile, compression, Flexure, ILSS, Open Hole Tension, Open Hole Compression and Shear (Iosipescu). The impact behaviour were characterised based on a low velocity drop weight impact carried on these laminates. The study shows that the basic properties evaluated were more dictated by the property of the S2-Glass used. The studies show that GLARE™ laminates posses’ high impact damage resistance compared to other composite material. All the test datas generated for this study will be brought out in this document

Non-Destructive Evaluation—A Pivotal Technology for Qualification of Composite Aircraft Structures

Tremendous advances in composite materials and a deeper understanding of their behavior have been responsible for the increased use of composites in the development of advanced, new generation civil and military aircraft. Composites play an important role in any aircraft development programme and are strong contenders to their metal counterparts due to their significant contributions towards improving strength, stiffness, fatigue properties & weight reduction. As materials, structural design & processing have evolved, strong emphasis is placed on effective & reliable damage detection, durability and damage tolerance. As a consequence, Non-destructive Evaluation (NDE) has also undergone significant advances towards meeting the growing demands of quality assurance. Advanced Composites Division (ACD) of National Aerospace Laboratories (NAL), has been involved in the development of composite structures for both civil and military aircraft for over a decade and a half. Innovative composite processing methods like co-curing/co-bonding have been successfully employed to realize airworthy structures. The role of NDE in the development of these structures has been critical and not limited to damage detection alone. On several occasions, NDE has provided valuable inputs towards improving design and process parameters. In-spite of the complexity of the structures, stringent quality requirements and tight delivery schedules, NDE has been successful in certifying these composite structures for airworthiness. This paper discusses the implementation of key NDE techniques like ultrasonics, radiography, acoustic emission and thermography for reliable flaw detection, characterization and quality assurance of composite aircraft structures

Least squares kinetic upwind method on moving grids for unsteady Euler computations

The present paper describes the extension of least squares kinetic upwind method for moving grids (LSKUM-MG). LSKUM is a kinetic theory based upwind Euler solver. LSKUM is a node based solver and can operate on any type of mesh or even on an arbitrary distribution of points. LSKUM-MG also has the capability to work on arbitrary meshes with arbitrary grid velocities. Results are presented for a moving piston problem and flow past an airfoil oscillating in pitch

Cultural Rivalry in Bharati Mukherjee's Wife and Jasmine

Bharati Mukherjee Indian-born American novelist and short-story writer who represented in her writing the cultural changes and variance in the immigrant experience.Cultural conflict is the clash between two cultures. Culture is the prime identity of human life. They have disclosed the futility of Western glamorous life and baseless romantic views.Both novels Wife and Jasmine journeys of two young women to the US for different reasons, under variousplace. It manifests East-West encounter and cultural conflicts in various forms.In this paper analysis cultural identity of the conflict arise in the novels. The main theme of extends that the writer who have broad mind with cultural problem in society. It focuses on the various reasons of cultural differences and possible causes of cultural conflicts

Impact of Non-Linear Electronic Circuits and Switch of Chaotic Dynamics

Switch-mode power supply is an extremely non-linear system that can inevitably exhibit unpredictable behavior. These control laws may be insufficient for nonlinear systems because they are not robust when the requirements on the dynamic characteristics of the system are strict [10]. Control laws that are insensitive to parameter variations, disturbances, and nonlinearities must be used. In this paper, we have tested the method of the first harmonic, used to analyses servo controls with a nonlinear element, and to predict certain non-linear behaviors. It mainly allows predicting the limit cycles, but also the jump phenomena, the harmonics as well as the responses of non-linear systems to sinusoidal inputs. We apply this method for the prediction of limit cycles and the determination of their amplitude and frequency. We take as an example a Boost converter controlled by current [4]. This system is chaotic when the duty cycle is more significant than 0.5: we then eliminate the chaos by applying the slippery mode command (for the ripple of the output voltage, for the current ripple of the inductance and switching frequency) when the output is periodic (duty cycle less than or equal to 0.5). In this article, we assess that established approach provides the best outcomes: it appears that the preference between the classical mode and the sliding mode depends heavily on the variance domain of the parameters E, R, and Iref

Frustrated square lattice with spatial anisotropy: crystal structure and magnetic properties of PbZnVO(PO4)2

Crystal structure and magnetic properties of the layered vanadium phosphate PbZnVO(PO4)2 are studied using x-ray powder diffraction, magnetization and specific heat measurements, as well as band structure calculations. The compound resembles AA'VO(PO4)2 vanadium phosphates and fits to the extended frustrated square lattice model with the couplings J(1), J(1)' between nearest-neighbors and J(2), J(2)' between next-nearest-neighbors. The temperature dependence of the magnetization yields estimates of averaged nearest-neighbor and next-nearest-neighbor couplings, J(1) ~ -5.2 K and J(2) ~ 10.0 K, respectively. The effective frustration ratio alpha=J(2)/J(1) amounts to -1.9 and suggests columnar antiferromagnetic ordering in PbZnVO(PO4)2. Specific heat data support the estimates of J(1) and J(2) and indicate a likely magnetic ordering transition at 3.9 K. However, the averaged couplings underestimate the saturation field, thus pointing to the spatial anisotropy of the nearest-neighbor interactions. Band structure calculations confirm the identification of ferromagnetic J(1), J(1)' and antiferromagnetic J(2), J(2)' in PbZnVO(PO4)2 and yield J(1)'-J(1) ~ 1.1 K in excellent agreement with the experimental value of 1.1 K, deduced from the difference between the expected and experimentally measured saturation fields. Based on the comparison of layered vanadium phosphates with different metal cations, we show that a moderate spatial anisotropy of the frustrated square lattice has minor influence on the thermodynamic properties of the model. We discuss relevant geometrical parameters, controlling the exchange interactions in these compounds, and propose a new route towards strongly frustrated square lattice materials.Comment: 14 pages, 9 figures, 5 table

The Magnetohydrodynamics of Convection-Dominated Accretion Flows

Radiatively inefficient accretion flows onto black holes are unstable due to both an outwardly decreasing entropy (`convection') and an outwardly decreasing rotation rate (the `magnetorotational instability'; MRI). Using a linear magnetohydrodynamic stability analysis, we show that long-wavelength modes are primarily destabilized by the entropy gradient and that such `convective' modes transport angular momentum inwards. Moreover, the stability criteria for the convective modes are the standard Hoiland criteria of hydrodynamics. By contrast, shorter wavelength modes are primarily destabilized by magnetic tension and differential rotation. These `MRI' modes transport angular momentum outwards. The convection-dominated accretion flow (CDAF) model, which has been proposed for radiatively inefficient accretion onto a black hole, posits that inward angular momentum transport and outward energy transport by long-wavelength convective fluctuations are crucial for determining the structure of the accretion flow. Our analysis suggests that the CDAF model is applicable to a magnetohydrodynamic accretion flow provided the magnetic field saturates at a sufficiently sub-equipartition value (plasma beta >> 1), so that long-wavelength convective fluctuations can fit inside the accretion disk. Numerical magnetohydrodynamic simulations are required to determine whether such a sub-equipartition field is in fact obtained.Comment: 17 pages including 3 figures. Accepted for publication in ApJ. New appendix and figure were added; some changes of the text were made in response to the referee

LARVICIDAL AND ENZYME INHIBITORY EFFECTS OF ACALYPHA FRUTICOSA (F.) AND CATHARANTHUS ROSEUS L (G) DON. LEAF EXTRACTS AGAINST CULEX QUINQUEFASCIATUS (SAY.) (DIPTERA: CULICIDAE)

ABSTRACTObjective: The prime objective of this study is to evaluate the larvicidal and enzyme inhibitory effects of Acalypha fruticosa and Catharanthus roseusleaf extracts against Culex quinquefasciatus.Methods: Insecticidal susceptibility tests were carried out using the World Health Organization standard method, and the mortality was observedafter 24 hrs exposure.Results: The tested extracts showed a significant larvicidal activity depending on the dose of the plant extracts. However, maximum larval mortalitywas detected in ethyl acetate extract of A. fruticosa with a lethal concentration (LC50) value of 253.08 ppm and (LC90) value of 455.40 ppm followedby hexane extract of C. roseus with LC50 value of 645.33 ppm and LC90 value of 1452.88 ppm against the larvae of C. quinquefasciatus. In control, therewere five different fractions of α-carboxylesterases resolved in the gel with the mobilities ranging between 0.14 and 0.66. β-carboxylesterase isozymeprofile of larvae treated with hexane extract of A. fruticosa showed higher enzyme activities by way of intense staining of fractions both at 1/4 and1/10 LC50 value of 48 hrs treatments. A. fruticosa ethyl acetate extract, and C. roseus hexane extract exposed larvae indicated increased quantitiesof β-Est4/5 isozymes in the concentration of 1/4 and 1/10 of LC50 value of 24 hrs treatment when compared to control. The protein quantity in themajority of treatments decreased compared to control.Conclusion: The results revealed that the organic leaf extract of A. fruticosa and C. roseus had significant larvicidal and enzyme inhibitory effectsagainst C. quinquefasciatus.Keywords: Acalypha fruticosa, Catharanthus roseus leaves extract, β-carboxylesterase, Culex quinquefasciatus, Lethal concentration50