Reliability assessment of 3D space frame structures applying stochastic finite element analysis

Throughout design development of satellite structure, stress engineer is usually challenged with randomness in applied loads and material properties. To overcome such problem, a risk-based design is applied which estimates satellite structure probability of failure under static and thermal loads. Determining probability of failure can help to update initially applied factors of safety that were used during structure preliminary design phase. These factors of safety are related to the satellite mission objective. Sensitivity-based analysis is to be implemented in the context of finite element analysis (probabilistic finite element method or stochastic finite element method (SFEM)) to determine the probability of failure for satellite structure or one of its components.     

Low-Temperature Processing of PZT Thick Film by Seeding and High-Energy Ball Milling and Studies on Electrical Properties

Lead zirconate titanate thick film with molecular formula PbZr_0.52Ti_0.42O₃ (PZT) was prepared by a modified conventional sol–gel method through seeding and high-energy ball milling, resulting in perovskite phase formation at lower temperatures. The ball-milling time was optimized by keeping the seed particle loading (5 wt.%) constant in the sol–gel solution. This methodology helped in reduction of the crystalline phase formation temperature to 300°C, which is much lower than that reported in the literature (450°C). The well-established perovskite phase was confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) of PZT films revealed uniform and crystalline microstructure. Film prepared by this methodology showed higher spontaneous polarization (2.22 μC/cm²), higher capacitance (1.17 nF), and low leakage current density (18 μA/cm²). The results obtained from ferroelectric characterization showed a strong correlation with the XRD and SEM results.     

Ultraviolet light effect on electrical properties of a flexible organic thin film transistor

We have fabricated pentacene-based transistors on a transparent and flexible substrate made of polyethylene-terephthalate. We have shown that using an optical excitation at a wavelength of 365 nm photoconductivity modifies the carrier density without changing the mobility. The performance of the flexible organic phototransistors is mostly due to high-photosensitivity in the off-state with a ratio of photocurrent to dark current of about 2 10⁴. Furthermore, the response times of the phototransistor are lower than 0.1 s. These results indicate that such transistors could be potentially used in photodetectors or amplifiers ordered by an optical gate. Moreover, we have noticed that there is no significant change in the mobility value when the transistor is bent in the direction of the current flow.     

Representation and extrapolation in multilayer perceptrons

To give an adequate explanation of cognition and perform certain practical tasks, connectionist systems must be able to extrapolate. This work explores the relationship between input representation and extrapolation, using simulations of multilayer perceptrons trained to model the identity function. It has been discovered that representation has a marked effect on extrapolation.     

Domain organization of the extracellular region of CD45

CD45 is a large, heavily glycosylated, transmembrane proteinphosphotyrosine phosphatase found on all nucleated cells ofhaematopoietic origin. In lymphocytes, the cytoplasmic phosphataseis necessary for efficient signalling through the antigen receptorbut in contrast little is known about the interactions of theextracellular region of the molecule. This consists of a mucin-likeregion, a novel cysteine-containing region and a region containingthree putative fibronectin type III domains. To confirm thisorganization and to identify parts potentially important forfunction, we have expressed fragments of the extracellular domainof rat CD45 as recombinant soluble proteins. Proteins correspondingto two, three and four domains of CD45 were expressed in secretedforms. Single domains and constructs for proteins with truncationsof the predicted domains were not expressed. This is consistentwith the proposed structural organization. Determination ofthe positions of the disulphide bonds in the N-terminal cysteine-containingregion and the first fibronectin type III domain identifiednovel disulphide bonds within the fibronectin type III domainand an unusual inter-domain disulphide linkage. Circular dichroismspectroscopy indicated that this region of rat CD45 has mainlyß-strand secondary structure and no -helical content.These studies support the proposed domain organization of CD45.     

Defining dimensions of distinctiveness: Group variability makes a difference to differentiation.

We tested the prediction, derived from an integration of social identity and self-categorization principles, that the relation between in-group distinctiveness and positive differentiation is curvilinear. Moderate distinctiveness is argued to provide the critical combination of intergroup difference (self-categorization theory) and intergroup similarity ( social identity theory ) to elicit intergroup differentiation. Intergroup distance (differences in group central tendencies) and group variability were manipulated orthogonally, resulting in different levels of intergroup distinctiveness (low, intermediate, and high). In line with predictions, in-group bias and positive differentiation were greatest, for both minimal and natural groups, when the combination of group variability and intergroup distance produced intermediate levels of group distinctiveness. The potential of this integrative model to account for disparate findings is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Optimization, simulation and multiple criteria in window design

Designing windows in buildings is a multicriteria, multivariable design problem with many constraints. This paper examines the different natures of the window design information that can be provided through mathematical simulation and optimization models and considers some approaches to choosing a solution.     

Facial dynamics as indicators of trustworthiness and cooperative behavior.

Detecting cooperative partners in situations that have financial stakes is crucial to successful social exchange. The authors tested whether humans are sensitive to subtle facial dynamics of counterparts when deciding whether to trust and cooperate. Participants played a 2-person trust game before which the facial dynamics of the other player were manipulated using brief (