Analysing admittance of obstacles in evanescent waveguide using the Imaginary Smith Chart

We present a technique, using the Imaginary Smith Chart, for determining the admittance of obstacles introduced into evanescent waveguide. The admittance of an inductive iris, capacitive iris, capacitive post, variable width strip and length of evanescent waveuide are investigated. © 2012 IEEE.

Increased Bandwidth Evanescent Open-Ended Waveguide Antenna Design Using the Imaginary Smith Chart

We present a novel antenna matching technique that uses the Imaginary Smith Chart to permit wideband matching of an evanescent open-ended waveguide antenna using a dielectric sheet air-spaced from the aperture. The fabricated antenna design is demonstrated to have a measured bandwidth of 24%, from 2.13–2.7 GHz, for reflection coefficient $qquad{<} -!!10~{rm dB}$ , with 2.725 GHz waveguide cutoff. The antenna's maximum aperture dimension is ${< 0.5}lambda_{0}$ at the upper frequency in the bandwidth and so it is suitable for use in a wide angle scanning phased array

The census and women's work in Rangoon, 1872–1931

The colonial census was a bureaucratic device which provided an essential abstraction from social reality, a ‘statistical fix’ designed to map individual social groups in space. This paper considers the contradictions associated with colonial knowledge systems as reflected in the census grafted onto Burmese society in the nineteenth and early twentieth centuries. It attempts to chart the general adoption and adaptation, in the Burmese context, of a classificatory scheme which categorised labour as either productive or unproductive. Colonialism introduced new attitudes towards work and labour which reinforced patriarchal values which contrasted with more egalitarian Burmese socio-economic systems. The paper suggests that a simple classification of women workers as either productive or unproductive in the Burmese census between 1872 and 1931 resulted in the devaluation of their status as workers. This devaluation was a function of both real economic transformation taking place in the empire and changes in census classification, reflecting a gendering of occupations that undermined the cultural norms of Burmese society. The material result was that women became statistically less visible as economically productive workers. Such ascriptions of value to women workers were largely informed by moral considerations originating in England.

Fault reconstruction in linear dynamic systems using multivariate statistics

Treasure et al. (2004) recently proposed a new sub space-monitoring technique, based on the N4SID algorithm, within the multivariate statistical process control framework. This dynamic-monitoring method requires considerably fewer variables to be analysed when compared with dynamic principal component analysis (PCA). The contribution charts and variable reconstruction, traditionally employed for static PCA, are analysed in a dynamic context. The contribution charts and variable reconstruction may be affected by the ratio of the number of retained components to the total number of analysed variables. Particular problems arise if this ratio is large and a new reconstruction chart is introduced to overcome these. The utility of such a dynamic contribution chart and variable reconstruction is shown in a simulation and by application to industrial data from a distillation unit.

Double potential step chronoamperometry at microdisk electrodes: simulating the case of unequal diffusion coefficients

An efficient approach to the simulation of the double potential step chronoamperometry at a microdisk electrode based on an exponentially expanding time grid and conformal mapping of the space is presented. The dimensionless second potential step flux data are included as a function of the first potential step duration and the ratio of the diffusion coefficients of the reacting species allowing instant analysis of the experimental double potential step chronoamperograms without a need for simulation. The values of the diffusion coefficients are determined for several test systems and found to be in good agreement with existing literature data. (C) 2004 Elsevier B.V. All rights reserved.

Graphical determination of network limits for wind power integration

A graphical method is presented for determining the capability of individual system nodes to accommodate wind power generation. The method is based upon constructing a capability chart for each node at which a wind farm is to be connected. The capability chart defines the domain of allowable power injections at the candidate node, subject to constraints imposed by voltage limits, voltage stability and equipment capability limits being satisfied. The chart is first derived for a two-bus model, before being extended to a multi-node power system. The graphical method is employed to derive the chart for a two-node system, as well as its application to a multi-node power system, considering the IEEE 30-bus test system as a case study. Although the proposed method is derived with the intention of determining the wind farm capacity to be connected at a specific node, it can be used for the analysis of a PQ bus loading as well as generation.

Stroke presentation and hospital management: comparison of neighbouring healthcare systems with differing health policies.

Background: Acute stroke care is shaped by healthcare policies. Differing policies in similar populations allow for assessment of policy impact on health and healthcare outcomes. Aims: To compare stroke presentation and hospital care in two adjacent healthcare systems with differing healthcare policies. Methods: Interviews and chart review of consecutive acute stroke admissions in Northern Ireland (n=103) and the Republic of Ireland (n=100). Results: Marked regional contrasts were evident for key aspects of hospital care. Northern Ireland performed significantly better on 15 of 16 quality of care (Sentinel Audit) items. Delivery on standards was significantly better in Northern Ireland for early assessment (Northern Ireland 72%; Republic of Ireland 54%, p

Stability of dust lattice modes in the presence of charged dust grain polarization in plasmas

We discuss the effect of the attractive force associated with overlapping Debye spheres on the dispersion properties of the longitudinal and transverse dust lattice waves in strongly coupled dust crystals. The dust grain attraction is shown to contribute to a destabilization of the longitudinal dust lattice oscillations. The (optic-like) transverse mode dispersion law is shown to change. due to the Debye sphere dressing effect, from the known inverse-dispersive ("backward wave") form into a normal dispersive law (i.e. the group velocity changes sign). The stability of one-dimensionless bi-layers, consisting of (alternating) negatively and positively charged dust particles, is also discussed. The range of parameter values (mainly in terms of the lattice parameter kappa) where the above predictions are valid, are presented. (c) 2005 Elsevier B.V. All rights reserved.

Relativistically correct hole-boring and ion acceleration by circularly polarized laser pulses

The problem of the 'hole-boring' (HB)-type of radiation pressure acceleration of ions by circularly polarized laser pulses interacting with overdense plasmas is considered in the regime where the dimensionless scaling parameter I/rho c(3) becomes large. In this regime a non-relativistic treatment of the 'HB' problem is no longer adequate. A new set of fully relativistic formulae for the mean ion energy and 'HB' velocity is derived and validated against one-dimensional particle-in-cell simulations. It is also found that the finite acceleration time of the ions results in large energy spreads in the accelerated ion beam even under the highly idealized conditions of constant laser intensity and uniform mass density.

'Wee women no more': female partners of republican political prisoners in Belfast

Studies of the female partners of politically motivated prisoners have generally studied women via a caring paradigm. Less well observed are those women who privately transgressed and challenged masculine-centred renditions or political imprisonment. This lacuna in the research dedicated to such women has been constructed around stereotypical depictions of them as a barely visible support network. We argue that the relatively indiscernible appearance of women who challenged such typecasting is attached to a persistent process of gender blindness within which women remain peripheral to wider narratives of collectivity and ideological presentation. We chart how some women actively involved themselves in creating their own identity as active agents, especially when the effects of conflict entered the private sphere.

Vaginal temperature sensing using UHF radio telemetry

User induced errors are common when women repetitively employ conventional probe type thermometers to chart their basal body temperatures in an effort to indicate ovulation. An alternative technique employing a two-part telemetric thermometer is proposed, with low-power, SAWR-controlled UHF radio as the transmission medium. Worn overnight in the vagina, the 1 mu W erp telemetry transmitter sends pulse modulated data continuously to a microcontroller in a nearby receiver; a real time clock enables programmable sampling and storage of the subject's temperature to 0.1 degrees C resolution. Initial clinical results indicate an enhanced performance compared to oral and axillary temperature trends taken by a mercury-in-glass thermometer. Polar plots of both the isolated and body-worn telemetry transmitte are presented; body indced attenuations of up to 30 dB were measured.

Transmission characteristics of a vaginally-worn UHF radio telemeter

A vaginally-worn temperature telemeter may be used by women to chart their basal body temperature for ovulation detection. The telemeter uses a temperature to pulse width converter to key a Colpitts oscillator which is controlled in frequency by a 418 MHz SAW resonator. The circuit’s tank inductor acts as a compact, multi-turn loop antenna with a radiated power in isolation of around 1 uW. The transmission characteristics of the system are affected by the proximity of the human body, which acts as an electrically-large lossy dielectric. The RF link-budget must allow for the reduction in total emitted power, directional body-induced fading, and polarization effects. The polar power patterns of the telemeter were measured for both isolated and in-situ cases, using horizontal and vertical polarization. The power patterns were numerically integrated to determine relative emitted power, and a reference dipole used to determine the emitted power for the isolated device. In isolation the telemeter radiation is vertically polarized and isotropic in nature. With the telemeter in-situ, total body absorption was found to be over 20 dB, with directional fades of up to 40 dB; there was extensive cross-polarization, with up to 60% of radiated power horizontally polarized. With limited radiated power and directional fading, the operating range for the telemeter is limited to single room operation (less than 10m). The majority of RF radiation is absorbed by the body, but the radiation hazard is negligible due to the low power level of the device. The high level of cross-polarization suggests that either horizontal or vertically polarized base-station antennas may be used.

Hydrodynamics and mixer-induced bubble formation in micro bubble columns with single and multiple-channels

A hydrodynamic characterization of an industrially used gas-liquid contacting microchannel. device is discussed, viz. the micro bubble column of IMM. Furthermore, similar characterization of a gas-liquid flow microchip of TU/e, with two tailored mixer designs, is used to solve fundamental issues on hydrodynamics, and therefore, to achieve further design and operating optimization of that chip and the IMM device. Flow pattern maps are presented in a dimensionless fashion for further predictions on new fluidic systems for optimum single-channel multiphase operation. Bubble formation was investigated in the two types of mixers and pinch-off and hydrodynamic decay mechanisms are observed. The impact of these mechanisms on bubble size, bubble size distributions, and on the corresponding flow patterns, i.e., the type of mixer design, can be decisive for the flow pattern map and thus, may be used to alter flow pattern maps. The bubble sizes and their distribution were improved for the tailored designs, i.e., smaller and more regular bubbles were generated. Finally, the impact of multi-channel distribution for gas and liquid flow is demonstrated. Intermediate flow patterns such as slug-annular flow, also found for single-phase operation, and the simultaneous coexistence of flow regimes are presented, with the latter providing evidence of flow maldistribution.