Determining polarization dependent diffraction coefficients from building edges using FDTD method

Electromagnetic waves in suburban environment encounter multiple obstructions that shadow the signal. These waves are scattered and random in polarization. They take multiple paths that add as vectors at the portable device. Buildings have vertical and horizontal edges. Diffraction from edges has polarization dependent characteristics. In practical case, a signal transmitted from a vertically polarized high antenna will result in a significant fraction of total power in the horizontal polarization at the street level. Signal reception can be improved whenever there is a probability of receiving the signal in at least two independent ways or branches. The Finite-Difference Time-Domain (FDTD) method was applied to obtain the two and three-dimensional dyadic diffraction coefficients (soft and hard) of right-angle perfect electric conductor (PEC) wedges illuminated by a plane wave. The FDTD results were in good agreement with the asymptotic solutions obtained using Uniform Theory of Diffraction (UTD). Further, a material wedge replaced the PEC wedge and the dyadic diffraction coefficient for the same was obtained.

Effect of processing parameters on the magnetic properties and macrotexture of a Nd13.5Fe73.8Co6.7B5.6Ga0.4 alloy processed by equal channel angular pressing with back pressure

Equal channel angular pressing (ECAP) is a well-established thermo-mechanical processing technique, which could induce the c-axis texture of Nd2Fe14B in a melt-spun Nd13.5Fe73.8Co6.7B5.6Ga0.4 alloy. However, the effects of ECAP processing parameters, such as temperature, back pressure (BP), and multiple-pass ECAP routes, remain unknown for this alloy. In this paper, we have investigated the effects of these processing parameters on the c-axis texture formation. It is found by X-ray diffraction macrotexture analysis that the maximum intensity of (001) pole figures for the tetragonal-Nd2Fe14B phase (Imax) shows an increase from 2.7 to 4.1 m.r.d. (multiples of random distribution) by increasing the ECAP temperature from 723 to 823 K, while the difference in remanent magnetization between easy and hard directions (Δ Mr) rises from 24.0 to 41.5 Am2/kg. When the BP was increased from 0.25 to 0.5 GPa at 823 K, Imax showed an increase from 2.8 to 4.1 m.r.d. However, Imax saturated for BPs above 0.5 GPa, suggesting that BP has limited effect on the texture formation, although it is necessary for the compaction of the alloy powders. Two multiple-pass ECAP routes conventionally known as routes A and C were employed for two-pass ECAP at 823 K. It is found that route A processing is effective in enhancing the texture formation, while the texture is lost by a subsequent pressing when adopting route C. Therefore, the compaction of Nd13.5Fe73.8Co6.7B5.6Ga0.4 alloy powder using route A ECAP passes with 0.5 GPa BP at 823 K results in pronounced texture, which is beneficial for anisotropic hard magnetic properties.

In-situ X-ray diffraction studies of slip and twinning in the presence of precipitates in AZ91 alloy

The effect of basal plate precipitates on the hardening of basal slip and {101¯2} twinning modes was investigated for a non-aged and aged AZ91 alloy in the twin dominated strain paths. Exploiting in-situ synchrotron and laboratory based X-ray diffraction methodologies, we quantified the critical resolved shear stress (CRSS) for basal slip and twinning modes. The twin volume fraction changes were quantified from the intensity changes with applied load. We observed that the twin volume fraction changes with plastic strain is sensitive to the initial texture, while the relative hardening of different deformation modes are considered as a secondary effect. We also found that the twin interior stresses were significantly smaller and consistent with the high twin back stresses in the presence of precipitates. We propose, based on a simple analytical equation, that the leading edge of the propagating twin have a Burgers vector equivalent to 100 twinning dislocations and when the propagating twin is blocked by a precipitate, relatively high resolved stress is required for bowing the twin dislocation and hence the propagation of the twin occurs by the dissociation of the leading edge of the twinning dislocation.

Advertising education in Australia: Looking back to the future

In Australia, advertising is a $13 billion industry which needs a supply of suitably skilled employees. Over the years, advertising education has developed from vocational based courses to degree courses across the country. This paper uses diffusion theory and various secondary sources and interviews to observe the development of advertising education in Australia from its early past, to its current day tertiary offerings, to discussing the issues that are arising in the near future. Six critical issues are identified, along with observations about the challenges and opportunities within Australia advertising education. By looking back to the future, it is hoped that this historical review provides lessons for other countries of similar educational structure or background, or even other marketing communication disciplines on a similar evolutionary path.

Wrong way, go back! Negotiating success in industry-based research

Literature addressing methodological issues in organisational research is extensive and multidisciplinary, encompassing debates about methodological choices, data-collection techniques, epistemological approaches and statistical procedures. However, little scholarship has tackled an important aspect of organisational research that precedes decisions about data collection and analysis – access to the organisations themselves, including the people, processes and documents within them. This chapter looks at organisational access through the experiences of three research fellows in the course of their work with their respective industry partners. In doing so, it reveals many of the challenges and changing opportunities associated with access to organisations, which are rarely explicitly addressed, but often assumed, in traditional methods texts and journal publications. Although the level of access granted varied somewhat across the projects at different points in time and according to different organisational contexts, we shared a number of core and consistent experiences in attempting to collect data and implement strategies.

Prevalence and correlates of low back pain among occupational therapy students in Northern Queensland

Background: Although low back pain (LBP) is an important issue for the health profession, few studies have examined LBP among occupational therapy students. Purpose. To investigate the prevalence and distribution of LBP, its adverse sequelae; and to identify potential risk factors.----------- Methods: In 2005, a self-reported questionnaire was administered to occupational therapy students in Northern Queensland.----------- Findings: The 12-month period-prevalence of LBP was 64.6%. Nearly half (46.9%) had experienced pain for over 2 days, 38.8% suffered LBP that affected their daily lives, and 24.5% had sought medical treatment. The prevalence of LBP ranged from 45.5 to 77.1% (p=0.004), while the prevalence of LBP symptoms persisting longer than two days was 34.1 to 62.5% (p=0.020). Logistic regression analysis indicated that year of study and weekly computer usage were statistically-significant LBP risk factors.----------- Implications: The occupational therapy profession will need to further investigate the high prevalence of student LBP identified in this study.

¡Latin jazz! : a syncretic journey from Spain, Cuba, the United States and back

The creative work, ¡Latin Jazz! is a 50 minute radio documentary to be broadcast on ABC Classic FM. It looks at the evolution of Latin jazz from Spain, Cuba and the United States. It examines the social effects on the style and specifically on the syncretic movement between the countries. The documentary traces my travel to Madrid, Spain and looks at Latin jazz through a deconstruction of the style, musical examples and interviews with prominent artists. Artists interviewed were Chano Domínguez, a Spanish flamenco jazz pianist, Bobby Martínez an American saxophonist, Alain Pérez a Cuban bassist and Pepe Rivero a Cuban pianist. The exegesis supports the radio documentary by examining the style in more depth, and is broken into three main sections. First it traces the historical relationship that occurred through the Ida y Vuelta (To and Fro), the similarities and influences through the habanera, the decíma and the religion of Santería. This is followed by specific musical elements within Latin jazz such as instrumentation, clave, harmony and improvisation, whilst the third section looks at the influences of the new syncretic movement back to Spain.