Template assisted synthesis of europium sulfide nanotubes

We report the template assisted synthesis of europium sulfide (EuS) nanotubes. These structures were fabricated by thermolysis of a single source precursor that was infused into porous alumina membranes. TEM and STEM analysis confirmed the formation of EuS nanotubes, while X-ray diffraction and selected area electron diffraction analysis probed their crystallinity. Room temperature optical spectroscopy identified an energy-band blue-shift in the absorption spectra into the UV, compared to bulk EuS. Interestingly, no such shift was observed in the photoluminescence. We attribute these changes to quantum confinement effects on the photoexcited charge carriers within the nanotubes' walls and strain-induced lattice deformations.     

Firefly Algorithm for Joint Estimation of Frequency Offsets and Channel in OFDMA Uplink

This paper addresses the problem of joint maximum-likelihood estimation of carrier frequency offsets, and channel responses in an orthogonal frequency division multiple access (OFDMA) uplink, which is a computationally-intensive, multiparameter, multidimensional problem. We propose to apply a recently-developed meta-heuristic algorithm called the firefly algorithm (FA) for the estimation of required parameters. We also introduce a new initialization procedure for the FA algorithm based on the separability of cost functions, which drastically reduces its computational complexity. A separate pilot OFDMA symbol is transmitted prior to the data symbols to estimate the parameters. The proposed technique is shown to achieve excellent performance at reduced computational complexity, especially at low signal-to-noise ratio. Also, it can be applied to OFDMA systems with any type of carrier assignment schemes. The significant features of the proposed estimation method are substantiated through extensive computer simulation studies and are compared with an important classical estimation technique available for the problem, to highlight its superiority.     

Sorptive storage of natural gas onto dry and wet phillipsite: Study of dynamics,storage and delivery

In this work, storage of methane on phillipsite, a naturally occurring zeolite, was studied on wet and dry basis. The temperature and pressure dynamics were investigated. The temperature gradient due to the adsorption of methane on phillipsite was less than 1 °C indicating higher thermal conductivity of this material. A decreased in temperature resulted in higher adsorption capacity. Storage of methane onto phillipsite can be enhanced by wetting the bed and thus hydrate formation. The time needed to reach equilibrium depends strongly on the water content of the adsorbent. The results revealed that the total delivery capacities for dry and wet phillipsite were 32.5 V/V and 74.13 V/V, respectively. A maximum delivery capacity of 138 V/V was reached using wet phillipsite with 350 g water content. The volumetric delivery capacity results indicated that the steady state delivery is more realistic for adsorptive natural gas (ANG) systems.     

Changes in adolescent online social networking behaviors from 2006 to 2009

As online social networking has become an immersive and pervasive phenomenon, traditional considerations and expectations of personal privacy have been drastically altered. This paradigmatic change has led to adolescents possibly making themselves vulnerable to embarrassment, censure, damage to one’s name or reputation, or even victimization by others because of unwise postings or revelations online. The current study sought to determine the extent to which adolescent information disclosure on MySpace.com has changed between 2006 and 2009. We found significant changes in the nature of personal content made publicly available across the two time points and a trend in which teens are being increasingly more selective and discrete when it comes to what they share and with whom they share it.     

Dehydration of potato slices following brief dipping in osmotic solutions: Effect of conditions and understanding the mechanism of water loss

A novel variant of osmotic dehydration, named here as postdipping dehydration—where a material is dipped in a salt or sugar solution for a very short time followed by simple exposure to ambient conditions was explored with the aim of lowering water content of potato slices but at the same time not gain a high level of sugar/salt. The rate of water loss, which was rapid initially, was found to approach equilibrium. This article also explored whether the water loss process could subsequently be kick started once again, by employing a multistage process, where each stage consisted of osmotic solution dipping followed by ambient holding of the potato slices that had reached equilibrium in the earlier stage. Water loss values comparable to conventional osmotic dehydration could be achieved thus, but with significantly lower overall solid gain (<50%)—which can potentially yield a significantly healthy product option.     

Technology in Engineering Education: What Do the Faculty Know and Want?

There currently exists a great interest in integrating technology into the engineering curriculum. The Southeastern University and College Coalition for Engineering Education (SUCCEED) has identified this topic to be one of four “focus areas” for the coalition, and is committed to supporting the effective use of technology in enhancing the learning and teaching environment. We report here the results of a survey of engineering faculty at the coalition universities to identify the training needs and present levels of experience with various technologies. The most surprising finding is that, despite the wide differences in the Coalition's colleges of engineering, the survey results are similar for all campuses. This implies that the results may be widely applicable to other universities. Generally, we found that the faculty's interest in receiving training in a specific technology is highly correlated with a low skill level for that topic, as expected. Of the ten potential workshop topics, those in highest demand include:

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Interactive publication: The document as a research tool

The increasing prevalence of multimedia and research data generated by scientific work affords an opportunity to reformulate the idea of a scientific article from the traditional static document, or even one with links to supplemental material in remote databases, to a self-contained, multimedia-rich interactive publication. This paper describes our concept of such a document, and the design of tools for authoring (Forge) and visualization/analysis (Panorama). They are platform-independent applications written in Java, and developed in Eclipse¹ using its Rich Client Platform (RCP) framework. Both applications operate on PDF files with links to XML files that define the media type, location, and action to be performed. We also briefly cite the challenges posed by the potentially large size of interactive publications, the need for evaluating their value to improved comprehension and learning, and the need for their long-term preservation by the National Library of Medicine and other libraries.