165 research outputs found
Predicting Small Bank Failure
There are many studies of bank performance and bank failure in the literature. Most of these studies used banking ratios as variables in their models without giving consideration to their appropriateness, nor was much consideration given to the stability of those ratios through time and across asset size. Many studies also failed to recognize that bank structure may differ by asset size. This study evaluates a large number of banking variables in order to identify stable ratios. These ratios are then used in disaggregated logistic models to predict bank failure. The study finds that the disaggregated models with stable variables were better predictors of bank failure than aggregated models used in earlier studies
Discrete-Layer Piezoelectric Plate and Shell Models for Active Tip-Clearance Control
The objectives of this work were to develop computational tools for the analysis of active-sensory composite structures with added or embedded piezoelectric layers. The targeted application for this class of smart composite laminates and the analytical development is the accomplishment of active tip-clearance control in turbomachinery components. Two distinct theories and analytical models were developed and explored under this contract: (1) a discrete-layer plate theory and corresponding computational models, and (2) a three dimensional general discrete-layer element generated in curvilinear coordinates for modeling laminated composite piezoelectric shells. Both models were developed from the complete electromechanical constitutive relations of piezoelectric materials, and incorporate both displacements and potentials as state variables. This report describes the development and results of these models. The discrete-layer theories imply that the displacement field and electrostatic potential through-the-thickness of the laminate are described over an individual layer rather than as a smeared function over the thickness of the entire plate or shell thickness. This is especially crucial for composites with embedded piezoelectric layers, as the actuating and sensing elements within these layers are poorly represented by effective or smeared properties. Linear Lagrange interpolation polynomials were used to describe the through-thickness laminate behavior. Both analytic and finite element approximations were used in the plane or surface of the structure. In this context, theoretical developments are presented for the discrete-layer plate theory, the discrete-layer shell theory, and the formulation of an exact solution for simply-supported piezoelectric plates. Finally, evaluations and results from a number of separate examples are presented for the static and dynamic analysis of the plate geometry. Comparisons between the different approaches are provided when possible, and initial conclusions regarding the accuracy and limitations of these models are given
Capactitive probe array measurements and limitations
This paper reviews the use of electrostatic capacitive probes for detections and evaluations of dielectric material properties and flaws. Interest in using both inductive and capacitive arrays for proximity sensing, surface feature characterization, material properties evaluation, and flaw detecting has increased steadily since the mid-1980âs [1â7]. Two other papers [6,7] in this proceedings also discuss the present state of the art, particularly with regard to the measurement of lossy dielectrics (complex permittivity). In traditional dielectrometry measurements (as well as in eddy-current measurements of material properties evaluation) varying the probe frequency has long been used as a tool for extracting information about dispersion and loss mechanisms. Use of a spatially periodic array probe interrogates the material, or flaw, with a field that penetrates into the sample to a degree determined by the periodicity. This controllable penetration phenomenon (artificial-skin effect or zoom effect) has been successfully exploited by Melcher, Zaretsky [5], and Goldfine [6] in what they call imposed w-k magnetometry and dielectrometry, using interdigital probes of different periodicities. Details are given in these proceedings. Gammellâs paper [7] gives a progress report on complex permittivity measurements using probes of more conventional type
Vibration and lateral buckling optimisation of thin-walled laminated composite channel-section beams
This study presents vibration and lateral buckling optimisation of thin-walled laminated composite beams with channel sections. While flanges' width, web-height, and fibre orientation are simultaneously treated as design variables, the objective function involves maximising the fundamental frequency and critical buckling moment. Based on the classical beam theory, the beam element with seven degrees of freedom at each node is developed to solve the problem. Micro Genetic Algorithm (micro-GA) is then employed as an optimisation tool to obtain optimal results. A number of composite channel-section beams with different types of boundary conditions, span-to-height ratios, and lay-up schemes are investigated for the optimum design. The outcomes reveal that geometric parameters severely govern the optimal solution rather than the fibre orientation and it is considerably effective to use micro-GA compared with regular GA in term of optimal solution and convergence rate
Chloroquine-Resistant Haplotype Plasmodium falciparum Parasites, Haiti
Chloroquine resistance is now present in this country
Force-based higher-order beam element with flexural-shear-torsional interaction in 3D frames. Part II: Applications
Modeling and analysis of waves in a heat conducting thermo-elastic plate of elliptical shape
Understanding the potential in vitro modes of action of bis(ÎČâdiketonato) oxovanadium(IV) complexes
To understand the potential in vitro modes of action of bis(ÎČ-diketonato) oxovanadium(IV) complexes, nine compounds of varying functionality have been screened using a range of biological techniques. The antiproliferative activity against a range of cancerous and normal cell lines has been determined, and show these complexes are particularly sensitive against the lung carcinoma cell line, A549. Annexin V (apoptosis) and Caspase-3/7 assays were studied to confirm these complexes induce programmed cell death. While gel electrophoresis was used to determine DNA cleavage activity and production of reactive oxygen species (ROS), the Comet assay was used to determine induced genomic DNA damage. Additionally, Förster resonance energy transfer (FRET)-based DNA melting and fluorescent intercalation displacement assays have been used to determine the interaction of the complexes with double strand (DS) DNA and to establish preferential DNA base-pair binding (AT versus GC)
Force-based higher-order beam element with flexuralâshearâtorsional interaction in 3D frames. Part I: Theory
Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection
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