237 research outputs found

    Assessing the Impact of Service Quality on Consumers Satisfaction: a Comparative Study of Commercial Vs Islamic Banks in Pakistan

    Full text link
    This study aims to show the path that Islamic banking follows of Sharia' h while on the other hand commercial banks obeys commercial regulations and rules for the purpose of banking. The main objective of the Islamic banking is to offer interest free services and products which obeys the path of Sharia' h and Islamic banking system makes transaction on the foundation of profit and loss, while on the other hand commercial banks are business oriented banks. The sampling method used in this research was convenience sampling with a sample size of 200 which were the customers of the banks and the research design of the questionnaire used was exploratory The questionnaire was distributed in 4 banks 2 commercial and 2 Islamic banks respectively. Dependent variables are ‘customer expectation and perception' while on the other hand independent variable that are used this research are ‘reliability, assurance, tangibles, empathy and responsiveness. The results which are derived from this research shows a negative or less impact of two service quality dimensions on both banks which are Assurance and Empathy. The highest perceived service dimension is “Reliability,” that refers to the reliability of their products and promise to provide the best service quality to their customers. While the lowest perceived service was observed towards “Empathy,” the other two dimension with highest value are tangibility and responsiveness which means that customers' of both commercial and Islamic banks like tangible service and the quick responsiveness towards providing them the best service

    Study of impact on helicopter blade

    Get PDF
    This article presents a study of damage in structures that are similar to helicopter blade sections, subjected to an impact. These complex composite structures were impacted by a steel ball of 125 g at impact speed ranging from 30 to 130 m/s. This led to properly highlight the kinematics of the impact and to define the sequence of the damage’s mechanisms. An explicit FE model is also presented. The damage modelling of the roving is performed through a scale change. It allows a good representation of observed experimental behaviour. As the mesh density is low, it can be used for the modelling of a real structure

    IMECE2002-33575 COHESIVE FINITE ELEMENT BASED MODELING OF DAMAGE IN COMPOSITE MATERIALS

    Get PDF
    ABSTRACT Damage in composite laminates affects its overall viscoelastic response. Constitutive equations have been developed for composite laminates considering a fixed damage state. A complete description, however, requires suitable damage evolution laws. This paper is focused on studying damage evolution in viscoelastic laminates using a cohesive finite element approach. A two dimensional, four nodded finite element is developed incorporating a rate-independent tractiondisplacement cohesive law. This element is used in conjunction with plane strain bulk elements behaving in a linear viscoelastic manner to simulate crack evolution between two existing transverse cracks in symmetric cross-ply laminates. The effects of loading strain-rate, ply constraint and initial crack density are studied. This study shows expected trends in the behavior and indicates the suitability of cohesive zone modeling to study damage evolution in viscoelastic composite materials

    An MFS Transporter-Like ORF from MDR Acinetobacter baumannii AIIMS 7 Is Associated with Adherence and Biofilm Formation on Biotic/Abiotic Surface

    Get PDF
    A major facilitator superfamily (MFS) transporter-like open reading frame (ORF) of 453 bp was identified in a pathogenic strain Acinetobacter baumannii AIIMS 7, and its association with adherence and biofilm formation was investigated. Reverse transcription PCR (RT-PCR) showed differential expression in surface-attached biofilm cells than nonadherent cells. In vitro translation showed synthesis of a ~17 kDa protein, further confirmed by cloning and heterologous expression in E. coli DH5α. Up to 2.1-, 3.1-, and 4.1- fold biofilm augmentation was observed on abiotic (polystyrene) and biotic (S. cerevisiae/HeLa) surface, respectively. Scanning electron microscopy (SEM) and gfp-tagged fluorescence microscopy revealed increased adherence to abiotic (glass) and biotic (S. cerevisiae) surface. Extracellular DNA(eDNA) was found significantly during active growth; due to probable involvement of the protein in DNA export, strong sequence homology with MFS transporter proteins, and presence of transmembrane helices. In summary, our findings show that the putative MFS transporter-like ORF (pmt) is associated with adherence, biofilm formation, and probable eDNA release in A. baumannii AIIMS 7

    A Thermodynamically-Based Mesh Objective Work Potential Theory for Predicting Intralaminar Progressive Damage and Failure in Fiber-Reinforced Laminates

    Get PDF
    A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Damage is considered to be the effect of any structural changes in a material that manifest as pre-peak non-linearity in the stress versus strain response. Conversely, failure is taken to be the effect of the evolution of any mechanisms that results in post-peak strain softening. It is assumed that matrix microdamage is the dominant damage mechanism in continuous fiber-reinforced polymer matrix laminates, and its evolution is controlled with a single ISV. Three additional ISVs are introduced to account for failure due to mode I transverse cracking, mode II transverse cracking, and mode I axial failure. Typically, failure evolution (i.e., post-peak strain softening) results in pathologically mesh dependent solutions within a finite element method (FEM) setting. Therefore, consistent character element lengths are introduced into the formulation of the evolution of the three failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs is derived. The theory is implemented into commercial FEM software. Objectivity of total energy dissipated during the failure process, with regards to refinements in the FEM mesh, is demonstrated. The model is also verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared to the experiments

    Computational Implementation of a Thermodynamically Based Work Potential Model For Progressive Microdamage and Transverse Cracking in Fiber-Reinforced Laminates

    Get PDF
    A continuum-level, dual internal state variable, thermodynamically based, work potential model, Schapery Theory, is used capture the effects of two matrix damage mechanisms in a fiber-reinforced laminated composite: microdamage and transverse cracking. Matrix microdamage accrues primarily in the form of shear microcracks between the fibers of the composite. Whereas, larger transverse matrix cracks typically span the thickness of a lamina and run parallel to the fibers. Schapery Theory uses the energy potential required to advance structural changes, associated with the damage mechanisms, to govern damage growth through a set of internal state variables. These state variables are used to quantify the stiffness degradation resulting from damage growth. The transverse and shear stiffness of the lamina are related to the internal state variables through a set of measurable damage functions. Additionally, the damage variables for a given strain state can be calculated from a set of evolution equations. These evolution equations and damage functions are implemented into the finite element method and used to govern the constitutive response of the material points in the model. Additionally, an axial failure criterion is included in the model. The response of a center-notched, buffer strip-stiffened panel subjected to uniaxial tension is investigated and results are compared to experiment

    On the fatigue response of a bonded repaired aerospace composite using thermography

    Get PDF
    Lock-in thermography was employed to investigate the repair efficiency of a bonded repaired aerospace composite subjected to step-wise cycling mechanical loading. The studied component (substrate) was artificially damaged with a 5 mm circular notch and subsequently repaired with a tapered bonded patch. Critical and sub-critical damage of the repaired component was monitored via thermography during 5 Hz tension–tension fatigue. The examination of the acquired thermographs enabled the identification of the patch debonding propagation as well as the quantification of the stress magnification at the patch ends and the locus of the circular notch. It was found that fatigue mechanical loading yields both thermoelastic and hysterestic phenomena with the latter being more prominent prior to the failure of the studied repaired component
    corecore