On a Possible Approximation of Changes in Elastic Properties of a Transversely Isotropic Material due to an Arbitrarily Oriented Crack

The present paper addresses an approximate analytical model for contribution of an arbitrarily oriented circular crack into effective elastic compliance of a transversely isotropic material. We numerically examine the bounds of applicability of the hypothesis that change in elastic potential due to an arbitrarily oriented circular crack in a transversely-isotropic material can be approximated by the change calculated for a certain isotropic environment. In particular, we obtained that the error of such an approximation is less than 20% if the extent of anisotropy is moderate – the ratio of Young’s moduli in transverse and in-plane directions is less than 1.87. The obtained result can be used for development of a simple model for microcracked transversely-isotropic materials with mild-to-moderate extent of anisotropy.     

On an Arbitrarily Oriented Crack in a Transversely-isotropic Medium

Transversely-isotropic material with an arbitrarily oriented penny-shaped crack is considered. We calculate fourth-rank compliance contribution tensor of the crack and second-rank crack opening displacement tensor and examine their dependence on crack orientation. It is shown that this dependence for the crack opening displacement tensor is negligible if transverse isotropy has elliptic character, i.e. if material symmetry can be described in terms of a certain second rank tensor.     

A social-interactional model of the development of depressive symptoms in adolescence.

This study used longitudinal, multimethod data to examine specific patterns of behavioral interaction with parents and peers that were hypothesized to predict increasing levels of depressive symptoms in early adolescence. Adolescents' struggles in establishing autonomy and relatedness in interactions with mothers, and a withdrawn, angry, or dependent pattern of behavior with a best friend, were assessed with observational and peer-report methods in a community sample of 143 adolescents, who were also assessed for levels of depressive symptoms at age 13 and with whom the authors followed up 1 year later. Study hypotheses were confirmed, with dysfunctional interaction patterns with parents and peers combining additively to account for substantial change variance in depressive symptoms over time. Results are interpreted as highlighting specific behavioral patterns that may be promising to address via psychosocial interventions targeting adolescent depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The mere exposure effect in patients with Alzheimer's disease.

The mere exposure effect was examined in patients with mild to moderate Alzheimer's disease (AD). Twenty patients and 20 elderly controls judged the physical characteristics of faces. Implicit memory was tested later by presenting pairs of faces (old and new) and asking participants which faces they liked better. Patients and controls exhibited above chance preference for previously exposed faces. Experiment 2 evaluated whether the preserved implicit memory of patients was mediated by explicit memory. Patients and controls again judged faces but then later chose which faces they had seen before. Patients exhibited impaired recognition memory compared to controls. These findings suggest that a mere exposure affect for unfamiliar faces is present in mild to moderate AD. The results are discussed in terms of perceptual and conceptual priming and relatively spared occipital lobe functioning in early AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of UV‐Radiation on the Packaging‐Related Properties of Whey Protein Isolate Based Films and Coatings

The high oxygen barrier properties of whey protein based films and coatings means these materials are of great interest to the food and packaging industry. However, these materials have poor mechanical properties such as the tensile strength, Young's modulus and elongation at break. Up until now, the influence of ultraviolet (UV) radiation on whey protein films has not been reported in the literature. This study thus investigates the influence of UV‐radiation on the properties of whey protein based films. UV‐irradiated films showed increased tensile strength and a yellowing that was dependent on the radiation time. After irradiation, the films showed no significant change in the barrier properties, Young's modulus or elongation at break. In addition, a protein solubility study was undertaken to characterize and quantify changes in structure‐property relationships. The significant decrease in protein solubility in buffer systems which break disulfide and non‐covalent bonds indicates that additional molecular interactions arise with increasing radiation dose. This study provides new data for researchers and material developers to tailor the characteristics of whey protein based films according to their intended application and processing. Copyright © 2015 John Wiley & Sons, Ltd.     

Substrate and Fe-doping effects on the hydrophilic properties of TiO2 thin films

Titanium dioxide films are known for their hydrophilic and photocatalytic characteristics. Increasing specific surface area and doping can enhance their photocatalytic activity and hydrophilicity. We report here results regarding the enhancement of the photocatalytic properties of titania by both controlling surface morphology and the anatase/rutile ratio. The samples were deposited on glass, indium tin oxide covered glass, and SrTiO₃ by sputtering and laser ablation techniques. Film structure and surface morphology were investigated by X-ray diffraction and atomic force microscopy. Film hydrophilicity was assessed from contact angle measurements during- and post-irradiation with UV light. The contact angle data are discussed in terms of the synergic effects of surface morphology, structure and composition of the films.     

A nonlinear inverse problem inspired by three‐dimensional diffuse tomography: Explicit formulas

We use time of flight information to obtain explicit inversion formulas for a simple model of optical tomography. This can be considered as an instance of a more general nonlinear inversion problem for multi‐terminal networks. In this case the network is nonplanar with lots of cycles but the underlying physical model yields a highly structured situation. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 198–203, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10031     

Autoclave-Free Formation of α-Hemihydrate Gypsum

Flue gas gypsum may be converted to α-hemihydrate by suspending the starting material in inorganic salt solutions of high concentration or in diluted sulfuric acid and maintaining the suspension at boiling, or near boiling temperature for a period of time. The crystal morphology of the produced α-hemihydrate gypsum and, thus, its quality depend significantly on the composition of the liquid phase. Additions of different carbonic acids may improve the quality of the product distinctly. Under optimal working conditions the quality of the formed α-hemihydrate gypsum is similar to that of a material produced in an autoclave.     

Behavioral effects of methylazoxymethanol-induced micrencephaly.

This study was prompted by reports of functionally normal humans with micrencephaly or cortical hypoplasia. Methylazoxymethanol acetate (MAM) treatment, which induces micrencephaly in rats, was administered by injection (20 mg/kg) on Gestational Day 14. Prior to weaning and into adulthood, offspring were assessed on many behavioral tests. There were 3 findings. First, MAM rats (forebrain weight less than two-thirds of controls) were not profoundly hyperactive. Increased activity was seen only on prolonged tests or after amphetamine administration. Second, MAM rats were hypoactive in some conditions. These rats were light shy and less likely to explore lighted areas. MAM rats appeared hyperreactive to environmental stimuli, but not hyperactive. Finally, no MAM effect on behavior was as large as that on brain weight. Thus, as with clinical findings, rat micrencephalics are more remarkable for functional sparing than for behavioral abnormalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)