A novel planar substrate integrated waveguide cavity resonator technique for measurement of complex permittivity is described, which has applications for dielectric measurement systems in the ...pharmaceutical industry. The high- Q resonant structure is a modernization of well-known measurement cells where the dielectric constant is deduced by cavity perturbation from the shift in resonant frequency and the change in the Q factor. The method uses extremely small amounts of a broad range of materials for accurate characterization. The ease of fabrication, low cost, and potential for integration with many other components on the same substrate allows it to be used in a disposable manner.
With the reduction in access to polymerase chain reaction (PCR) testing and changes in testing guidelines in Australia, a reduced number of people are seeking testing for coronavirus disease ...(COVID-19), limiting the opportunity to monitor disease transmission. Knowledge of community transmission of COVID-19 and other respiratory viruses is essential to better predict subsequent surges in cases during the pandemic to alert health services, protect vulnerable populations and enhance public health measures. We describe a methodology for a testing-based sentinel surveillance program to monitor disease in the community for early signal detection of SARS-CoV-2 and other respiratory viruses.
A longitudinal active testing-based sentinel surveillance program for respiratory viruses (including SARS-CoV-2, influenza A, influenza B and Respiratory Syncytial Virus) will be implemented in some regions of Queensland. Adults will be eligible for enrolment if they are part of specific community groups at increased risk of exposure and have not had a COVID-19 infection in the last 13 weeks. Recruitment via workplaces will occur in-person, via email and through online advertisement. Asymptomatic participants will be tested via PCR for SARS-CoV-2 infection by weekly self-collected nasal swabs. In addition, symptomatic participants will be asked to seek SARS-CoV-2 and additional respiratory virus PCR testing at nominated COVID-19 testing sites. SARS-CoV-2 and respiratory virus prevalence data will be analysed weekly and at the end of the study period.
Once implemented, this surveillance program will determine the weekly prevalence of COVID-19 and other respiratory viruses in the broader community by testing a representative sample of adults, with an aim to detect early changes in the baseline positivity rate. This information is essential to define the epidemiology of SARS-CoV-2 in the community in near-real time to inform public health control measures and prepare health services and other stakeholders for a rise in service demand.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background With the reduction in access to polymerase chain reaction (PCR) testing and changes in testing guidelines in Australia, a reduced number of people are seeking testing for coronavirus ...disease (COVID-19), limiting the opportunity to monitor disease transmission. Knowledge of community transmission of COVID-19 and other respiratory viruses is essential to better predict subsequent surges in cases during the pandemic to alert health services, protect vulnerable populations and enhance public health measures. We describe a methodology for a testing-based sentinel surveillance program to monitor disease in the community for early signal detection of SARS-CoV-2 and other respiratory viruses. Methods/design A longitudinal active testing-based sentinel surveillance program for respiratory viruses (including SARS-CoV-2, influenza A, influenza B and Respiratory Syncytial Virus) will be implemented in some regions of Queensland. Adults will be eligible for enrolment if they are part of specific community groups at increased risk of exposure and have not had a COVID-19 infection in the last 13 weeks. Recruitment via workplaces will occur in-person, via email and through online advertisement. Asymptomatic participants will be tested via PCR for SARS-CoV-2 infection by weekly self-collected nasal swabs. In addition, symptomatic participants will be asked to seek SARS-CoV-2 and additional respiratory virus PCR testing at nominated COVID-19 testing sites. SARS-CoV-2 and respiratory virus prevalence data will be analysed weekly and at the end of the study period. Discussion Once implemented, this surveillance program will determine the weekly prevalence of COVID-19 and other respiratory viruses in the broader community by testing a representative sample of adults, with an aim to detect early changes in the baseline positivity rate. This information is essential to define the epidemiology of SARS-CoV-2 in the community in near-real time to inform public health control measures and prepare health services and other stakeholders for a rise in service demand.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The large-ion-accessible surface area of carbon nanotubes (CNTs) and graphene sheets formed as yarns, forests, and films enables miniature high-performance supercapacitors with power densities ...exceeding those of electrolytics while achieving energy densities equaling those of batteries. − Capacitance and energy density can be enhanced by depositing highly pseudocapacitive materials such as conductive polymers on them. ,− Yarns formed from carbon nanotubes are proposed for use in wearable supercapacitors. , In this work, we show that high power, energy density, and capacitance in yarn form are not unique to carbon materials, and we introduce niobium nanowires as an alternative. These yarns show higher capacitance and energy per volume and are stronger and 100 times more conductive than similarly spun carbon multiwalled nanotube (MWNT) and graphene yarns. ,− The long niobium nanowires, formed by repeated extrusion and drawing, achieve device volumetric peak power and energy densities of 55 MW·m–3 (55 W·cm–3) and 25 MJ·m–3 (7 mWh·cm–3), 2 and 5 times higher than that for state-of-the-art CNT yarns, respectively. The capacitance per volume of Nb nanowire yarn is lower than the 158 MF·m–3 (158 F·cm–3) reported for carbon-based materials such as reduced graphene oxide (RGO) and CNT wet-spun yarns, but the peak power and energy densities are 200 and 2 times higher, respectively. Achieving high power in long yarns is made possible by the high conductivity of the metal, and achievement of high energy density is possible thanks to the high internal surface area. No additional metal backing is needed, unlike for CNT yarns and supercapacitors in general, saving substantial space. As the yarn is infiltrated with pseudocapacitive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), the energy density is further increased to 10 MJ·m–3 (2.8 mWh·cm–3). Similar to CNT yarns, niobium nanowire yarns are highly flexible and show potential for weaving into textiles and use in wearable devices.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Design techniques for microwave bandpass filters using re-entrant resonators are presented. The key feature is that each re-entrant resonator in the filter generates a passband resonance and a finite ...frequency transmission zero above the passband. Thus, an N th degree filter can have N finite frequency transmission zeros with a simple physical realization. A physically symmetrical five-pole re-entrant bandpass filter prototype with five transmission zeros above the passband was designed and fabricated. Measured results showed good correspondence with theories.
The increasing understanding of the advantages offered by fish and insect-like locomotion is creating a demand for muscle-like materials capable of mimicking nature's mechanisms. Actuator materials ...that employ voltage, field, light, or temperature driven dimensional changes to produce forces and displacements are suggesting new approaches to propulsion and maneuverability. Fundamental properties of these new materials are presented, and examples of potential undersea applications are examined in order to assist those involved in device design and in actuator research to evaluate the current status and the developing potential of these artificial muscle technologies. Technologies described are based on newly explored materials developed over the past decade, and also on older materials whose properties are not widely known. The materials are dielectric elastomers, ferroelectric polymers, liquid crystal elastomers, thermal and ferroelectric shape memory alloys, ionic polymer/metal composites, conducting polymers, and carbon nanotubes. Relative merits and challenges associated with the artificial muscle technologies are elucidated in two case studies. A summary table provides a quick guide to all technologies that are discussed.
This work presents a new design technique for dual-mode dielectric-loaded resonator filter operating at 2.18 GHz by using T-shape coupling probe. A cylindrical dielectric puck is suspended in the ...middle of metallic cavity and short-circuited on the side walls. Four vertically etched-slots through the dielectric puck from the top to the base of the ceramic puck offer a high unloaded quality factor of 4300 at the fundamental ${\rm T}{\rm E}_{11\delta }$TE11δ mode and allows the T-shape coupling to be located close to the centre of the dielectric puck. The size reduction ratio in this resonator was 11% compared with air-filled coaxial resonator. Fourth-poles Chebyshev bandpass filter with planar configuration was designed and implemented by employing two dielectric-loaded cavities. The experimental results show that the spurious-free window of ∼820 MHz from the fundamental frequency of 2.18 GHz and the operational bandwidth of 77 MHz were achieved.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A four-port diplexer consisting of two back-to-back three-port diplexers combined with a 180° phase shifter in one branch is presented. The technique achieves high Tx/Rx isolation with relatively low ...degree filters. Two experimental diplexers are demonstrated, one with equal Q resonators in all filters and the other with dissimilar Q factors, enabling miniaturisation and cost reduction. Measured results of Tx/Rx diplexer devices at 2.13/1.73 GHz are presented and 40 dB Tx/Rx isolation is achieved with only second-order filters.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Volterra kernel stochastic system identification is a technique that can be used to capture and model nonlinear dynamics in biological systems, including the nonlinear properties of skin during ...indentation. A high bandwidth and high stroke Lorentz force linear actuator system was developed and used to test the mechanical properties of bulk skin and underlying tissue
in vivo
using a non-white input force and measuring an output position. These short tests (5 s) were conducted in an indentation configuration normal to the skin surface and in an extension configuration tangent to the skin surface. Volterra kernel solution methods were used including a fast least squares procedure and an orthogonalization solution method. The practical modifications, such as frequency domain filtering, necessary for working with low-pass filtered inputs are also described. A simple linear stochastic system identification technique had a variance accounted for (VAF) of less than 75%. Representations using the first and second Volterra kernels had a much higher VAF (90–97%) as well as a lower Akaike information criteria (AICc) indicating that the Volterra kernel models were more efficient. The experimental second Volterra kernel matches well with results from a dynamic-parameter nonlinearity model with fixed mass as a function of depth as well as stiffness and damping that increase with depth into the skin. A study with 16 subjects showed that the kernel peak values have mean coefficients of variation (CV) that ranged from 3 to 8% and showed that the kernel principal components were correlated with location on the body, subject mass, body mass index (BMI), and gender. These fast and robust methods for Volterra kernel stochastic system identification can be applied to the characterization of biological tissues, diagnosis of skin diseases, and determination of consumer product efficacy.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
New methods for the design of tunable combline bandpass and bandstop filters are presented. The first part of this paper presents a tunable bandstop filter designed using a dual-band circuit with ...wide passband and integrated narrow stopband. A prototype has been constructed and measured results shows that the bandwidth remained constant at 30 MHz as the filter was tuned from 3.22 GHz to 3.66 GHz. The second part of this paper presents a tunable bandpass filter designed using a dual-band circuit with both wide passband and stopband. The response corresponds to two narrow passbands, where the lower passband bandwidth and center frequency can be tuned. A prototype has been constructed and measured results demonstrate wide centre frequency tuning range and over 300% bandwidth tuning without the need for coupling adjustment.
PDF
