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Mechanical behavior of a woven graphite/PMR-15 composite at room and elevated temperatures determined from the ±45° tensile, and Iosipescu shear tests

Failure and stiffness properties of a woven 8 harness satin (8HS) graphite/PMR-15 composite have been investigated at room temperature and at 315°C by performing the ±45° tensile and Iosipescu tests. Acoustic emission has been monitored during testing. The critical loads for the initiation of damage in the composite have been determined. In particular, the specimen width effect has been investigat

The effect of sandblasting on the initiation of stress corrosion cracking in unidirectional E-glass/polymer composites used in high voltage composite (non-ceramic) insulators

The purpose of this research is to examine the effect of sandblasting on the initiation of stress corrosion cracking (SCC) in unidirectional E-glass/polymer composite materials with modified polyester, epoxy and vinyl ester resins. The composites with different amounts of surface damage due to sandblasting have been subjected to mechanical bending loads in the presence of nitric acid (pH=1.2). It

Analyses of composite insulators with crimped end-fittings : Part II - Suitable crimping conditions

In this research the mechanical behavior of composite suspension insulators with crimped end-fittings manufactured by NGK has been evaluated. Two issues have been addressed in this study. Insulators crimped with the standard, high, reversed and constant high stress conditions have been analyzed for their crimping deformations, and the two and three dimensional compression profiles for the four dif

Analyses of composite insulators with crimped end-fittings : Part I - Non linear finite element computations

The purpose of this research has been to design an advanced numerical model that can be used to evaluate the mechanical behavior of composite insulators with crimped end-fittings subjected to axial tensile loads. Two issues have been addressed in this study. First, examples of insulator failures due to improper crimping have been shown and discussed. Second, comprehensive nonlinear two- and three-

Comparison of the ± 45° tensile and iosipescu shear tests for woven fabric composite materials

The mechanical response of a woven eight-harness satin graphite/polyimide composite has been investigated by performing ± 45° tensile and Iosipescu shear tests at room temperature. Nonlinear finite element simulations of the tests have been conducted to determine internal stress distributions in the ±45° tensile and Iosipescu fabric specimens as a function of load. In the experimental part of this

Determination of interlaminar residual thermal stresses in a woven 8HS graphite/PMR-15 composite using X-ray diffraction measurements

This work is a continuation of the research recently presented in [1] and [2] on the determination of residual thermal stresses in graphite/polyimide composites with and without externally applied bending loads. In the previous work [1, 2] a combined experimental and numerical methodology for the determination of the residual stresses in unidirectional graphite/PMR-15 composites based on X-ray dif

Failure Analysis of ±45° Off-Axis Woven Fabric Composite Specimens

The purpose of this research is to evaluate the mechanical response of eight harness satin woven graphite/polyimide composite specimens using the ±45 ° test. A series of tensile tests have been conducted at room temperature to evaluate the effect of specimen width as well as monotonie, progressive, and multiple loadings on the response of the composite specimens. Acoustic emission techniques have

The use of X-ray diffraction measurements to determine the effect of bending loads on internal stresses in aluminum inclusions embedded in unidirectional graphite-fibre/PMR-15 composite

A testing methodology for the determination of residual thermal stresses in the polymer-matrix of unidirectional polymer-matrix composites has been proposed in Ref. [1] [Benedikt B, Kumosa M, Predecki PK, Kumosa L, Castelli MG, Sutter JK. An analysis of residual thermal stresses in a unidirectional graphite/PMR-15 composite based on the X-ray diffraction measurements. Composites Science and Techno

An analysis of residual thermal stresses in a unidirectional graphite/PMR-15 composite based on X-ray diffraction measurements

The purpose of this research is to determine residual thermal stresses in a unidirectional graphite-fiberT/PMR-15 polyimide composite by using crystalline inclusions. X-ray diffraction (XRD) measurements have been made to determine residual stresses in embedded aluminum and silver inclusions placed between the first and second plies of six-ply unidirectional graphite/PMR-15 composite specimens. In

An evaluation of the critical conditions for the initiation of stress corrosion cracking in unidirectional E-glass/polymer composites

The purpose of this work is to establish the critical surface conditions leading to the initiation of stress-corrosion cracks on the assupplied surfaces of three unidirectional E-glass/polymer composites with modified polyester, epoxy and vinyl ester resins subjected to a nitric acid solution without mechanical loads. The composite materials considered in this study are commonly used in composite

Initiation of stress-corrosion cracking in unidirectional glass/polymer composite materials

The purpose of this research is to determine the resistance to stress-corrosion cracking (SCC) of three unidirectional (pultruded) E-glass/polymer composites based on modified polyester, epoxy and vinyl ester resins. The composites have been subjected to a nitric acid solution of pH 1.2 in a newly designed four-point bend fixture. The stress-corrosion process was initiated on the as-supplied surfa

[18F]PSMA-1007 renal uptake parameters: Reproducibility and relationship to estimated glomerular filtration rate

BackgroundScintigraphy with technetium-99m-labelled dimercaptosuccinic acid ([99mTc]Tc-DMSA) is widely used for renal cortical imaging. Uptake of [99mTc]Tc-DMSA has been shown to correlate with glomerular filtration rate (GFR). Prostate-specific membrane antigen (PSMA) radiopharmaceuticals used for positron emission tomography (PET) show high renal uptake and are being investigated for renal imagi

Gray matter hypoperfusion is a late pathological event in the course of Alzheimer's disease

Several studies have shown decreased cerebral blood flow (CBF) in Alzheimer's disease (AD). However, the role of hypoperfusion in the disease pathogenesis remains unclear. Combining arterial spin labeling MRI, PET, and CSF biomarkers, we investigated the associations between gray matter (GM)-CBF and the key mechanisms in AD including amyloid-β (Aβ) and tau pathology, synaptic and axonal degenerati

ESTRO ACROP and SIOPE recommendations for myeloablative Total Body Irradiation in children

BACKGROUND AND PURPOSE: Myeloablative Total Body Irradiation (TBI) is an important modality in conditioning for allogeneic hematopoietic stem cell transplantation (HSCT), especially in children with high-risk acute lymphoblastic leukemia (ALL). TBI practices are heterogeneous and institution-specific. Since TBI is associated with multiple late adverse effects, recommendations may help to standardi

Set in Motion : Paradoxical narratives of becoming Swedish digital media influencers

This article analyzes how Swedish digital media influencers make sense of their careers in print media interviews and autobiographical books. I explore how influencers use meta-phors involving motion, speed and acceleration to describe, explain and legitimate the various circumstances and phases of their career development, and how these metaphors may be viewed in the wider context of social accel

Evolvability and constraint in the evolution of three-dimensional flower morphology

Premise: Flower phenotypes evolve to attract pollinators and to ensure efficient pollen transfer to and from the bodies of pollinators or, in self-compatible bisexual flowers, between anthers and stigmas. If functionally interacting traits are genetically correlated, response to selection may be subject to genetic constraints. Genetic constraints can be assessed by quantifying standing genetic var