Justification of a certain algorithm for shape optimization in 3D elasticity

The trabecular bone adapts its form to mechanical loads and is able to form structures that are both lightweight but very stiff. In this sense, it is a problem (for the Nature or living entities) similar to the structural optimization, especially the topology optimization. The structural optimization system developed by the authors previously was based directly on the bio-mechanical models. The paper aims to clarify the approach of using the bio-mechanical models of the trabecular bone remodelling phenomenon as a base for the structural optimization. The justified algorithm for shape optimization mimics the natural phenomenon to satisfy the condition of constant value of the strain energy density on the structural surface, issuing from the considerations in the area of mechanics. The main body of the paper contains the analysis of the stiffness optimization problem in the framework of speed method approach to shape optimization. The given numerical example (cantilever beam in bending) includes the influence of the structural surface curvature on the optimization procedure. The presented in the paper approach can be used as a method of structural optimization unrelated already to trabecular bone remodelling phenomenon.     

Cyclostationary modelling of rotating machine vibration signals

This paper is dedicated to modelling rotating machine signals as cyclostationary processes, with strong emphasis on the peculiarities and pitfalls that this issue implies. The objective is to demonstrate that machine signals require specific processing that are much more subtle than for communication signals—from which the paradigm of cyclostationarity was originally issued from and developed for. First, different types of cyclostationarity embracing a multitude of rotating machine signals are distinguished. In particular, the importance of considering pure rather than impure cyclostationarity is stressed out. Next, the relationships between angle and time cyclostationarity are investigated and some useful results are derived. It is shown that vibration signals exhibit cyclostationarity if and only if the random speed fluctuation of the machine is periodic, stationary or cyclostationary. Finally, a comprehensive methodology is proposed for processing actual cyclostationary signals: three typical examples dealing with vibration signals of an IC engine, a gearbox and a rolling element bearing are presented, each of them being characterised by a different type of cyclostationarity. The methodology proposed in this paper is general enough and may serve as a guideline for modelling and analysing other types of rotating machine signals, such as pressure signals, electric signals, etc.     

IR Technique for Studies of Microwave Assisted Drying

This article examines the idea of using an infrared technique in obtaining temperature profiles in solid particles heated with microwaves. The geometry of a cylinder and a regular prism made from thermally and structurally different materials (potato and gypsum) were tested. A suitability of the IR photography for visualization and quantification of temperature distribution in heated samples has been confirmed. Symmetrical temperature profiles were detected in cylinders in contrast to non-symmetrical ones in prisms.     

Influence of ultrasound on mass transport during cheese brining

 The effect of ultrasound on mass transfer during cheese brining has been investigated. The rate of water removal and NaCl gain increased when ultrasound was applied in comparison with brining performed under static or dynamic conditions, suggesting that ultrasound improves both external and internal mass transfer. A simple diffusional model was developed to simulate mass transport during acoustic brining. Model parameters were estimated using experimental data from acoustic brining experiments carried out on cheese cylinders of 1.7×10^–2m radius and 3×10^–2 m height at different temperatures (5, 15 and 20  °C). Effective water (D _W) and NaCl (D _S) diffusivities estimated using the proposed model ranged from 5.0×10^–10m²/s and 8.0×10^–10 m²/s at 5  °C to 1.3×10^–9m²/s and 1.2×10^–9 m²/s at 20  °C. Both D _W and D _S varied with temperature according to the Arrhenius equation. Through the proposed model, water losses and NaCl gains of the experiments used in the parameter identification were accurately simulated (average %var=98.2%) and also of two additional acoustic experiments carried out under different conditions of temperature (10  °C) and sample size and geometry [parallelepiped of (6×2.5×1.25)×10^–2 m] to those used in the parameter identification (average %var=98.4%). Received: 22 September 1998 / Revised version: 20 November 1998     

Perceived Partner Reactions to Diagnosis and Treatment of Breast Cancer: Impact on Psychosocial and Psychosexual Adjustment.

Two studies examined breast cancer patients' perceptions of their partners' reactions to their diagnosis and treatment as influences on 3 aspects of patients' well-being: psychosexual adjustment, emotional distress, and marital satisfaction. Study 1, cross-sectional, indicated that partner initiation of sex, frequency of sex, a positive 1st sexual experience after treatment, and especially perception of the partner's emotional involvement in the relationship, were relevant to these outcomes. Study 2, longitudinal, confirmed many of these findings in prospective tests across 1 year of recovery after surgery. Partner involvement prospectively predicted all 3 outcomes. Partner initiation of sex predicted greater marital satisfaction; partner adverse reaction to the scar predicted less marital satisfaction. Rated quality of the 1st sexual experience after treatment predicted less distress. The pattern suggests that women's impressions of their partners' emotional involvement after surgery for breast cancer forecast their adjustment in sexual, marital, and emotional arenas over the following year. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A two-scale Weibull approach to the failure of porous ceramic structures made by robocasting: Possibilities and limits

This paper introduces our approach to modeling the mechanical behavior of cellular ceramics, through the example of calcium phosphate scaffolds made by robocasting for bone–tissue engineering. The Weibull theory is used to deal with the scaffolds’ constitutive rods statistical failure, and the Sanchez-Palencia theory of periodic homogenization is used to link the rod- and scaffold-scales. Uniaxial compression of scaffolds and three-point bending of rods were performed to calibrate and validate the model. If calibration based on rod-scale data leads to over-conservative predictions of scaffold's properties (as rods’ successive failures are not taken into account), we show that, for a given rod diameter, calibration based on scaffold-scale data leads to very satisfactory predictions for a wide range of rod spacing, i.e. of scaffold porosity, as well as for different loading conditions. This work establishes the proposed model as a reliable tool for understanding and optimizing cellular ceramics’ mechanical properties.     

Social Support, Positive States of Mind, and HIV Treatment Adherence in Men and Women Living With HIV/AIDS.

Numerous studies have linked social support to better medication adherence among illness groups, but few have examined potential mechanisms for this relationship. Relationships were examined between social support, depression, positive states of mind (PSOM), and medication adherence among HIV positive men who have sex with men (n = 61) and women (n = 29) on highly active antiretroviral therapy. Depression and PSOM were evaluated as potential mediators of the relationship between support and adherence. Cross-sectional data showed that greater social support and PSOM related to better adherence whereas higher depression scores related to nonadherence. PSOM partially mediated the relationship between social support and adherence. PSOM may be an important mechanism through which social support is related to better medication adherence in this population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Curvilinear associations between benefit finding and psychosocial adjustment to breast cancer.

Two previously studied cohorts of women with nonmetastatic breast cancer (Ns = 230 and 136) were reexamined. Participants were assessed during the year after surgery and 5-8 years later. Associations were examined between benefit finding (BF) and several indicators of psychosocial adjustment (e.g., perceived quality of life, positive affect, negative affect, social disruption, and intrusive thoughts). Significant curvilinear relations between BF and other outcomes were observed cross-sectionally during initial assessment and at long-term follow-up in both samples. Compared with the intermediate BF group, low and high BF groups had better psychosocial adjustment. Further analyses indicated that the high BF group reported higher optimism and more use of positive reframing and religious coping than the other BF groups. Discussion highlights the need to examine nonlinear as well as linear relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)