A generic virtual reality interaction system and its extensions using the common object request broker architecture (CORBA)

The paper describes the design and implementation of an immersive Virtual Reality (VR) interaction system. The system aims to provide a flexible mechanism for programmers to implement interaction in their VR applications, making good use of all accepted practices in the field. The paper further describes how the system was extended to a multi-user system using the CORBA middleware layer.

A genre analysis of reprint request emails written by EFL and physics professionals

The present study aimed to analyze reprint request e-mail messages written by postgraduates (MA students) of two fields of study, namely Physics and EFL, to realize the differences and similarities between the two email types. The results showed that the two corpora were much alike at the level of move schemata while there were some differences concerning strategies and microstructural features. The results showed that the two corpora were much alike at the level of move schemata while there were some differences concerning strategies and microstructural features. The email writers within each discipline were affected by their previously learned texts and the physics group was affected by the conventions of Persian letter writing. The email writers within each discipline were affected by their previously learned texts and the physics group was affected by the conventions of Persian letter writing

The inhibition of hydrogen embrittlement in SAE 4340 steel in an aqueous environment with the rare earth compound lanthanum 4 hydroxy cinnamate

A preliminary study showed that the inhibitor lanthanum 4-hydroxy cinnamate ((La4OHcin)₃) at a concentration of 400 ppm prevented the hydrogen embrittlement (HE) of SAE 4340 steel tensile specimens when tested under slow strain rate conditions in a 0.01M NaCl. In the presence of the inhibitor, a complex film formed on the surface of specimens during the slow strain rate test (SSRT), and no corrosion pits were detected. Electrochemical polarization studies indicated that the La(4OHcin)₃ acted as an anodic inhibitor in the NaCl solution. This article also discusses the mechanism of HE inhibition by La(4OHcin)₃.

Semi-supervised and compound classification of network traffic

This paper presents a new semi-supervised method to effectively improve traffic classification performance when few supervised training data are available. Existing semi supervised methods label a large proportion of testing flows as unknown flows due to limited supervised information, which severely affects the classification performance. To address this problem, we propose to incorporate flow correlation into both training and testing stages. At the training stage, we make use of flow correlation to extend the supervised data set by automatically labeling unlabeled flows according to their correlation to the pre-labeled flows. Consequently, the traffic classifier has better performance due to the extended size and quality of the supervised data sets. At the testing stage, the correlated flows are identified and classified jointly by combining their individual predictions, so as to further boost the classification accuracy. The empirical study on the real-world network traffic shows that the proposed method outperforms the state-of-the-art flow statistical feature based classification methods.

Request mitigating devices in Australian English and Iraqi Arabic : a comparative study

Speech acts realization in everyday interaction is seen as an important field to explore the impact of linguistic and cultural variations on cross-cultural communication and second language acquisition. The reported study investigates the use of request mitigating devices in Australian English and Iraqi Arabic. It explores the internal and external devices that speakers of the two languages use to mitigate the imposition force of requests and the impact of the linguistic and cultural parameters on this use. Request samples were collected from 14 native speakers of Australian English and 14 native speakers of Iraqi Arabic by means of eight role-play interviews. The mitigating devices were identified and classified according to a modified categorization scheme based on Blum-Kulka et al. (1989). Additional categories of mitigating devices were added to this scheme to meet the requirements of data analysis. These include consultative device (Blum-Kulka & Olshtain, 1984), questions (Trosborg, 1995), apology (Economidou-Kogetsidis, 2008), alerter (Schauer, 2007), closing (Al-Ali & Alawneh, 2010), and new categories: wish/hope statement and verbal incentive. The results showed that internal mitigating devices were more frequent in Australian English requests than in Iraqi Arabic requests, while external mitigating devices were equally pervasive in both groups. The two groups also used different semantic formulae of some mitigating devices in specific situations. The pervasive occurrence of external mitigators in both groups‟ requests is discussed in terms of volubility as a politeness strategy. It is suggested that the divergence between the two groups in their utilization of request mitigations is related to linguistic and cultural variations between the Australian and Iraqi languages and cultures.

Request mitigating devices in Australian English and Iraqi Arabic : a comparative study

Significant issues, especially miscommunication in a cross-cultural setting and pragmatic failure in second language (L2) acquisition, stem from the linguistic and cultural differences between social groups. The investigation of speech acts realization in everyday situations is deemed as an important field to explore the impact of linguistic and cultural variations on cross-cultural communication and L2 acquisition. This paper examines the internal and external mitigating devices that Australian English native speakers (AENSs) and Iraqi Arabic native speakers (IANSs) use to soften the force of request speech acts in everyday situations. It aims to explore request mitigating devices employed in Australian English and Iraqi Arabic in terms of semantic formulae and frequencies in everyday interaction. Request samples were collected from native speakers of Australian English and Iraqi Arabic by means of role-play interviews. The mitigating devices found in requests were identified and classified. The results showed that internal mitigating devices were more frequent in AENSs’ requests than in IANSs’ requests, while external mitigating devices were pervasive in both groups. The two groups also used different semantic formulae of some mitigating devices in some situations. The pervasive occurrence of external mitigators in both groups’ requests is explained in terms of the notion of volubility as a politeness strategy. It is also suggested that the divergence between the two groups in their utilization of request mitigations is related to linguistic and cultural variations between the Australian and Iraqi cultures.

Large compound vesicles from amphiphilic block copolymer/rigid-rod conjugated polymer complexes

Morphology evolution in complexes of amphiphilic block copolymers poly(styrene)-b-poly(acrylic acid) (PS-b-PAA) and poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO) in the presence of polyaniline (PANI) in aqueous solution is reported. Transmission electron microscopy, atomic force microscopy, and dynamic light scattering techniques were used to study the morphologies at various PANI contents [aniline]/[acrylic acid] ([ANI]/[AA]) ranging from 0.1 to 0.7. The interpolyelectrolyte complex formed between PAA and PANI plays a key role in the morphology transformation. Spherical micelles formed from pure block copolymers were transformed into large compound vesicles upon increasing PANI concentration due to internal block copolymer segregation. In addition to varying PANI content, the kinetic pathway of nanoparticle formation was controlled through different water addition methods and was critical in the formation of multigeometry nanoparticles.

Finite element analysis of residual stresses in metallic coatings through a compound casting

Al and Mg alloys are widely used in industry as main lightweight alloys. They have excellent properties, such as low density, high ductility, and high specific strength, and so on. Generally speaking, Mg alloys are better than Al alloys. However the corrosion of Mg alloys is much more difficult to control compared Al alloys. Therefore to combine these two lightweight alloys, a composite-like structure is an ideal solution since Al alloys can be used as protective coatings for Mg alloys. Compound casting is a realistic technique to get this coating system. In the current study, we numerically study the compound casting using finite element method (FEM) to make these two alloys, a composite-like structure, satisfy requirements to resist corrosion required from industry, in which the aluminum layer is acting as a protective coating for the magnesium substrate. Several finite element models have been developed by using the birth and death element technique and we focus on compound casting-induced residual stresses in the compounded structure. The numerical results obtained from the proposed finite element models show the distribution profiles of thermal residual stresses. We found the major factors influencing the residual stresses are the temperature to pre-heating the Al substrate and the thickness of Mg deposits. © (2014) Trans Tech Publications, Switzerland.

Synthesis of Al-doped Mg2Si1-xSnx compound using magnesium alloy for thermoelectric application

Abstract Mg2Si1-xSnx thermoelectric compounds were synthesized through a solid-state reaction at 700 °C between chips of Mg2Sn-Mg eutectic alloy and silicon fine powders. The Al dopants were introduced by employing AZ31 magnesium alloy that contains aluminum. The as-synthesized Mg2Si1-xSnx powders were consolidated by spark plasma sintering at 650-700 °C. X-ray diffraction and scanning electron microscopy revealed that the Mg2Si1-xSnx bulk materials were comprised of Si-rich and Sn-rich phases. Due to the complex microstructures, the electrical conductivities of Mg2Si1-xSnx are lower than Mg2Si. As a result, the average power factor of Al0.05Mg2Si0.73Sn0.27 is about 1.5 × 10^-3 W/mK² from room temperature to 850 K, being less than 2.5 × 10^-3 W/mK² for Al0.05Mg2Si. However, the thermal conductivity of Mg2Si1-xSnx was reduced significantly as compared to Al0.05Mg2Si, which enabled the ZT of Al0.05Mg2Si0.73Sn0.27 to be superior to Al0.05Mg2Si. Lastly, the electric power generation from one leg of Al0.05Mg2Si and Al0.05Mg2Si0.73Sn0.27 were evaluated on a newly developed instrument, with the peak output power of 15-20 mW at 300 °C hot-side temperature.