Entrenched compartmentalisation and students’ abilities and levels of interest in science

This article explores the notion that asking and exploring so-called ‘big questions’ could potentially increase the diversity and number of students who aspire to work in science and science-related careers. The focus is the premise that girls are more interested than boys in the relationships between science and other disciplines. The article also examines the view that the practice of entrenched compartmentalisation is squeezing students’ curiosity and channelling their thinking away from creative activities such as identifying good questions to ask and devising ways to address them. Based on their findings, the authors suggest that entrenched compartmentalisation could be a barrier in schools to students’ intellectual progression and to students’, particularly girls’, interest in science

Effects of a Smaller Unit Cell Planar EBG Structure on the Mutual Coupling of a Printed Dipole Array

A new smaller unit-cell planar electromagnetic bandgap (EBG) structure is proposed on low dielectric constant low-cost substrate (TMM: epsilon(r) = 4.5, thickness = 25 mils) that has a stopband frequency at around 4 GHz. The proposed structure when placed in between a two-element printed dipole array results in over 13-dB reduction in mutual coupling and a significant improvement in antenna return loss bandwidth and gain pattern

(In) Direct Effects of Customer-Defined Market Orientation on Brand Loyalty through Purchase Intention and Brand Image: A Parallel Mediation Approach

This study investigates the impact of market orientation on brand loyalty, primarily through variables pertaining to the purchase intention and brand image. In order to achieve this aim, this study have resorted to testing the relationships between customer-defined market orientation and purchase intention, and the brand image, leading to brand loyalty. In this regard, the study is quantitative in nature, and uses the cross-sectional design. For this purpose, the primary data were collected from gold jewelry customers (n = 413) from Karachi, Pakistan. Three key findings emerged from the structural model testing. The first finding revealed that the customer, competitor and interventional orientation are positively associated with the purchase intention, brand image and loyalty of gold jewelry customers. Secondly, in simple mediation, the purchase intentions and brand image tend to fully mediate the impact of customer orientation, and competitor orientation on the brand loyalty of gold jewelry customers, while partially mediating the association between the interfunctional coordination and brand loyalty. The third finding revealed that, in parallel to the mediation effect, the impact of customer, competitor and interfunctional orientation on brand loyalty is fully mediated by the purchase intention and brand image. This research is useful for gold jewelry businesses and business owners, since on a comparative level, less research has been conducted in the domestic industry of Pakistan

On the dynamics of high-risk fertility in Bangladesh

Our aim in this study is to explore the dynamics of age-pattern of childbearing and risk fertility among Bangladeshi women. By using age-specific fertility rates of 21 age schedules from 1986 to 2006 contribution of early, on time and delayed childbearing on total fertility rates are studied and time trend behavior of risk fertility is observed. Our study explored that the level of early childbearing seems to be stagnant over the years. The decrement of the high-risk fertility is due to the decrease of total fertility rates, however, the contribution of early childbearing to the total fertility rates is unchanged and contribution of early childbearing to the high-risk fertility is more influential than the delayed childbearing. The ratio of risk-birth is plateau at the same level even after twenty years. Possible policies to reduce the risk-birth are also discussed in this paper

Performance Dependences of Multiplication Layer Thickness for InP/InGaAs Avalanche Photodiodes Based on Time Domain Modeling

InP/InGaAs avalanche photodiodes (APDs) are being widely utilized in optical receivers for modern long haul and high bit-rate optical fiber communication systems. The separate absorption, grading, charge, and multiplication (SAGCM) structure is an important design consideration for APDs with high performance characteristics. Time domain modeling techniques have been previously developed to provide better understanding and optimize design issues by saving time and cost for the APD research and development. In this work, performance dependences on multiplication layer thickness have been investigated by time domain modeling. These performance characteristics include breakdown field and breakdown voltage, multiplication gain, excess noise factor, frequency response and bandwidth etc. The simulations are performed versus various multiplication layer thicknesses with certain fixed values for the areal charge sheet density whereas the values for the other structure and material parameters are kept unchanged. The frequency response is obtained from the impulse response by fast Fourier transformation. The modeling results are presented and discussed, and design considerations, especially for high speed operation at 10 Gbit/s, are further analyzed

Method and apparatus for evaluating multilayer objects for imperfections

A multilayer object where the layers are arranged in a stacking direction is evaluated for imperfections such as voids, delaminations, and microcracks. First, an acoustic wave is transmitted into the object in the stacking direction via an appropriate transducer/waveguide combination. The wave propagates through the multilayer object and is received by another transducer/waveguide combination preferably located on the same surface as the transmitting combination. The received acoustic wave is correlated with the presence or absence of imperfections by generating pulse echo signals indicative of the received acoustic wave, wherein the successive signals form distinct groups over time. The respective peak amplitudes of each group are sampled and fitted to an exponential curve, wherein a substantial fit of approximately 80-90 percent indicates the absence of imperfections. Alternatively, the time interval between distinct groups can be measured, wherein equal intervals indicate the absence of imperfections and unequal intervals indicate the presence of imperfections

All-optical high speed NOR gate based on two photon absorption in silicon wire waveguides

We demonstrate for the first time an all-optical logic NOR gate in submicron size silicon wire waveguides. High speed operation at equivalent 80Gbps data rate was achieved using pump induced non-degenerate two-photon absorption inside the waveguides. The device requires low pulse energy (few pJ) for logic gate operation. (C) 2005 Optical Society of America

Wideband Smaller Unit-Cell Planar EBG Structures and Their Application

A new low-cost smaller unit-cell planar electromagnetic bandgap (ERG) structure operating at the lower GHz frequencies (below 6 GHz) is proposed. ERG structures based on this new geometry are designed on a number of commonly available substrates. Characteristics of such structures, such as bandgap and reflection phase profile are analyzed. a simple empirical model is proposed to predict the surface wave stopband frequency of the proposed ERG structure. Finally, a low-profile dipole antenna is designed and tested for operation on the ERG structure

Disbond Detection Using Peak Amplitude of Pulse-Echo Signals for Various Thicknesses and Transducer Frequencies

The potential for flaws such as disbonds, corrosion, and microcracks in aircraft lap joints and reinforced doublers is a major problem in the aircraft industry today due to the increasing average age of existing aircraft. Several advanced nondestructive testing techniques are being developed for aircraft inspection, including ultrasonics, thermography, eddy currents, X-radiography, and shearography. The focus of this study is to establish a science base for a cost-effective, reliable, and portable ultrasonic system that can be used for nondestructive detection of disbonds in aircraft structure