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The Kosciuszko Bridge carries a 1.8 km long segment of the Brooklyn–Queens Expressway over Newtown Creek between Brooklyn and Queens in New York City, USA. The roadway is a vital link in the region's transportation network, carrying over 170 000 vehicles/day. Owing to structural and operational deficiencies, the existing structure was replaced. The new bridge consists of two parallel structures, one eastbound and one westbound, with main spans mirroring one another. Each structure consists of a single-tower cable-stayed main span over Newtown Creek with unbalanced main and back spans. This was the first cable-stayed bridge to be constructed in New York City, joining the ranks of the city's most iconic bridges. Here, two main span structures are discussed, with the focus primarily on the design and construction of the westbound, phase 2 bridge. Some key design aspects are outlined, including outboard cable anchorages, a concrete-filled counterweight and other details intended to facilitate construction, maintenance and inspection. The eastbound, phase 1 bridge was constructed under a design–build contract, and the westbound, phase 2 bridge as a design–bid–build. The paper also touches on some of the design aspects that were refined during the second phase. [ABSTRACT FROM AUTHOR]

In this study, a novel frequency beam‐scanning (FBS) antenna based on composite substrate integrated waveguide/spoof surface plasmon polariton (SIW/SSPP) waveguide is proposed. The composite SIW/SSPP slow‐wave waveguide is designed by embedding a series of periodic subwavelength H‐shaped grooves on the top surface of the SIW. Its transmission characteristics own both the features from SIW and SSPP, and can be flexibly mansplained by tuning the key structural parameters. To convert the propagating composite slow‐wave mode into the radiation mode effectively, a new flexible digital modulation method with staggered metallic vias is proposed and used. The presented beam‐scanning antenna has a simple feeding structure, a single dielectric layer, and a compact volume of 0.75 × 8.55 × 0.015 λ03. A prototype of the antenna is fabricated and tested to verify its performance. The experimental results demonstrate that the proposed antenna can realise a continuous beam‐scanning angle of 49° in an operating bandwidth of 8.7–9.2 GHz with a high frequency‐scanning sensitivity (FSS) of 9.8 °/100 MHz−1. Moreover, the measured results indicate that the antenna has high peak gain with an average level of 12.7 dBi, high radiation efficiency with an average level of 87%, and stable unidirectional radiation pattern in the working band. [ABSTRACT FROM AUTHOR]

In this paper, we propose a newly developed impedance method to gauge the variations of multidirectional strain using a near-circular-patch based sensor. A novel three-dimensional (3D) feeding mechanism realized by a 90-deg bended microstrip line is devised for allowing strain detection along any direction in the azimuth plane of a metallic surface. The simulated results, verified by experimental results, demonstrate that there is a linear relationship between normalized impedance and multi-directional strain with high sensitivities of about 100 ppm/με. The relationship between sensitivity and sensor orientation is derived as a cosine function, which is a useful feature for estimating principal strain direction. [ABSTRACT FROM AUTHOR]

This article presents a novel decoupling technique for the circularly polarized multiple-inputmultiple-output (CP-MIMO) system composed of Guoshaped patch antennas. A comparative study has been conducted on antenna performance as a function of packing distance before and after applying the technique. A prototype of two-element Guo-shaped patch MIMO at a small inter-element spacing of 12.5 mm has devised aiming for the 5G new radio n38 (2.57-2.62 GHz) applications. Simulation reinforced with experimental results confirmed the effectiveness of the proposed technique, whereas the two Guo-shaped patch elements packed in such small spacing can be operated independently. Both the envelope correlation coefficient and diversity gain are approaching their ideal values. [ABSTRACT FROM AUTHOR]

Unknown dielectric properties of RF/microwave substrates cause headaches for microwave circuit and antenna designers. Most commercial reinforced dielectric substrates made from layers of woven‐glass and/or ceramic fillings lead to dielectric anisotropy. Often, re‐optimization and even re‐fabrication of designed prototypes are required when measuring results are found to be departed from the prediction. These are time consuming and costly. In order to determine the unknown complex permittivity of any substrates, this paper describes a hybrid approach composed of two measurement stages. The first stage is the coaxial‐probe method for predicting an initial complex permittivity of unknown dielectric substrates, which is known as the perpendicular permittivity. The second stage is the microstrip open‐circuit stub (OCS) method that regulates the complex permittivity of the dielectric laminate by mapping the input impedance curves of OCS via electromagnetic simulation and actual measurement. Three dielectric substrates without prior dielectric properties were selected to validate the proposed method. The equivalent dielectric constants, dissipation factors and dielectric anisotropies were determined and compared. The proposed method is found to be reliable for determining the unknown properties of dielectric substrates. [ABSTRACT FROM AUTHOR]

This paper presents a study into the parameter‐retrieval methods of metasurfaces composed of isolated metallic unit‐cells. The classical method based on the effective‐medium theory is revisited by aiming at the point of effective thickness in use. The second method based on the generalized sheet transition conditions is also investigated and the extracted results are mutually verified with the classical method when the unity thickness is used. It is found that these two sets of effective parameters, surface susceptibilities and unity effective parameters, are mutually equivalent if they are not equal. The retrieved values are justified by those results available in literature. [ABSTRACT FROM AUTHOR]

This research communication introduces a Chinese‐character artistic antenna, wherein a Guo‐shaped patch antenna is devised for circular‐polarization applications. The novelty is emphasized by Guo‐shaped patch printed in standard SimHei font at the antenna's front end. The artistic patch antenna is singly‐fed and cavity‐backed by a metallic‐box reflector to enhance the forward directivity (~7dBic) and the front‐to‐back radiation ratio (~20 dB). The Guo‐shaped patch exhibits an axial‐ratio bandwidth of 120 MHz that covers the 2.4 GHz band of wireless local‐area network (WLAN) IEEE 802.11b/g/n/ax. The proposed antenna owns an overall dimension of 1λo × 1λo × 0.11λo at 2.5 GHz. ©2018 Wiley Periodicals, Inc. Int J RF and Microwave. [ABSTRACT FROM AUTHOR]

In this article, we present a comparative study into the directional sensitivity of patch‐antenna‐based strain sensors. Two linearly‐polarized (LP) patch sensors vs a circularly‐polarized (CP) patch sensor with identical configurations are demonstrated. The strain occurred in real structures is commonly uncertain, the usefulness of LP‐patch sensor becomes limited. Like the conventional strain gauges, it can only be used if the strain direction is known beforehand. Therefore, a nearly‐square CP‐patch sensor for multi‐directional strain monitoring is proposed here. In order to obtain high sensitivity, three novel strain sensing methods are proposed for strain monitoring. Multi‐directional strain sensing is achieved by a proof‐of‐concept prototype. The simulated results verified by experimental results show that high sensitivities of these three methods were achieved. [ABSTRACT FROM AUTHOR]

This paper presents experimental investigation on the effect of specimen shapes of engineered cementitious composites (ECCs). In various types of cement concrete, cubic specimens have shown to have higher compressive strength than cylindrical specimens. However, no research has been conducted yet to study the effect of specimen shapes (cube or cylinder) on the compressive strength of new cementitious materials like ECC. In this study, cylinders and cubic specimens were prepared to study the effect on the compressive strength and elastic modulus of the ECCs. In addition, the effects of water-to-binder ratio (w / b) and polyvinyl alcohol (PVA) fiber on the compressive strength and the modulus of elasticity of ECC were investigated. Two categories of ECC were considered, with PVA fibers (PVA-ECC or shortly PE) and without PVA fibers (NO-PVA-ECC or simply NE). Three different w / b ratios were used for each material category. The results revealed that PVA fiber has a significant effect on ductility of ECCs but with minor effect on compressive strength for both the specimen shapes. As expected, the cubic specimens of ECC exhibit higher strengths than the cylindrical counterparts after 28 days. Based on the measurement data, new generalized correlation models were proposed via linear regression analysis showing the relation between the cylindrical and cubic shapes for ECC at 14 and 28 days of age. Another interesting models are proposed to establish the correlations between the compressive strength as well as the moduli of elasticity of ECCs with and without PVA fiber, for both specimen shapes. [ABSTRACT FROM AUTHOR]

This research article presents dual-frequency correlation models for predicting the growth of elasticity and flexural strength of engineered cementitious composites (ECCs) using microwave nondestructive inspection technique. Parallel measurements of microwave properties and mechanical properties of ECC specimens were firstly undertaken in the sense of cross-disciplinary experiments. Regression models were developed via means of nonlinear regression to the measured data. The purpose of the study is: (i) to monitor the flexural strength and elasticity growth; and (ii) to predict their mature values under the influence of different initial water contents, via microwave effective conductance at early ages. It has been demonstrated that both the modulus of rupture (MOR) and modulus of elasticity (MOE) can be accurately modeled and correlated by microwave conductance using exponential functions. The moduli developed as a function of conductance whereas the regression coefficient exhibited a linear relation with water-to-binder ratio. These findings have highlighted the effectiveness of the microwave non-destructive technique in inspecting the variation of liquid phase morphology of ECCs. The dual-frequency correlation can be used for structural health monitoring, which is not only for prediction but also provides a means of verification. [ABSTRACT FROM AUTHOR]

This paper analyzes major categories of renewable policy instruments in light of the framework of Transition Management. We leveraged the concept of levelized cost of electricity (LCOE) to unify the discussion of these instruments by elaborating the differing effects such instruments have on the formation of the socio-technological regime. Regimes are sets of grammer. logics and contexts which enable and constrain the interaction of actors associated with a physical technology. We compare these instruments by assuming the normative organization objective of a regime to be that of enhancing the cost-effectiveness of respective instruments. In other words, the socio-technological regime is to be organized and optimized to improve the LCOE of the energy technology. Our main contribution is to propose the rationalization of the regime objective and the implications to regime management and development strategy. This in turn would facilitate a much needed synthesis of normative and evolutionary deliberation in the framework of Transition Management. [ABSTRACT FROM AUTHOR]

ABSTRACT We propose a low-cost solution for performance enhancement and polarization rotation of a waveguide antenna by using an anisotropic metasurface. The antenna is being considered as reconfigurable, where its polarizations can be controlled by changing the alignment angle of striplines on the metasurface in order to fulfil the polarization diversity. Both simulation and experimental results verify that the metasurfaced waveguide antenna can operate in the lower GSM bandwidth from 698 to 960 MHz, with a gain that varies from 5.8 to 7.8 dBi. The waveguide antenna has a compact form size of 0.70λo × 0.39λo × 0.47λo at 698 MHz. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1084-1087, 2017 [ABSTRACT FROM AUTHOR]

A broadband circularly-polarized antenna array with unidirectional radiation has been proposed. The 2 × 2 array is considered as an artistic array composed of Chinese character – Wang-shaped patches, arranged in a rhombic lattice. The subarray exhibits broadband performance with a 3-dB axial-ratio bandwidth of 62%, 15-dB return-loss bandwidth of 57.6%, maximum gain of 12 dBic and a 9-dB gain bandwidth of 29.5%. The antenna array features a compact profile of 1.25λ o × 1.88λ o × 0.14λ o at 2.5 GHz. For the design of a broadband circularly polarized array, spacing between elements remains a crucial parameter that critically affects the array performance. However, method and justification in determining an optimized spacing are rarely reported in literature. As a new contribution, this paper presents a study in this aspect. [ABSTRACT FROM AUTHOR]

In this Letter, a novel miniaturisation technique for a 3-dB quadrature hybrid coupler is described. The revolutionary structure is composed of folded microstrip lines and folded coplanar waveguides that are printed on the top- and bottom-surfaces of a dielectric substrate, respectively. The two different planar lines are connected by copper vias to form the double-path composite microstrip-coplanar waveguide (CMCPW) line. To demonstrate the effectiveness of the technique, a simple yet miniaturised hybrid coupler is devised by introducing folded S-shaped CMCPW-lines, wherein their lengths are gradually changed to address the design goals. The simulated and measured results of the proposed coupler validate its good performance metrics in the amplitude responses of power splitting, return- and insertion-loss. Moreover, its isolation and quadrature phase between outputs have been examined. A very small footprint size of 0.0667λ0× 0.0667λ0 at 0.5 GHz has been realised. [ABSTRACT FROM AUTHOR]

In this Letter, a novel miniaturisation technique for a 3‐dB quadrature hybrid coupler is described. The revolutionary structure is composed of folded microstrip lines and folded coplanar waveguides that are printed on the top‐ and bottom‐surfaces of a dielectric substrate, respectively. The two different planar lines are connected by copper vias to form the double‐path composite microstrip‐coplanar waveguide (CMCPW) line. To demonstrate the effectiveness of the technique, a simple yet miniaturised hybrid coupler is devised by introducing folded S‐shaped CMCPW‐lines, wherein their lengths are gradually changed to address the design goals. The simulated and measured results of the proposed coupler validate its good performance metrics in the amplitude responses of power splitting, return‐ and insertion‐loss. Moreover, its isolation and quadrature phase between outputs have been examined. A very small footprint size of 0.0667λ0 × 0.0667λ0 at 0.5 GHz has been realised. [ABSTRACT FROM AUTHOR]

This study analyses the effect of replacing existing synchronous generators (SGs) equipped with power system stabilisers (PSS) by doubly fed induction generator (DFIG) based wind farms on the damping of power system oscillations in a multi-machine power system. A power system stabiliser was designed to enhance the capability of DFIG to damp power systems oscillations. The validity and effectiveness of the proposed controller are demonstrated on the widely used New England 10-machine 39-bus test system that combines conventional SGs and DFIG based wind farms using eigenvalue analysis and non-linear simulation. The non-linear simulation is used to demonstrate how the damping contribution of DFIG based wind farms is affected by different operating conditions within the same wind farm and stochastic wind speed behaviour. The results show that installing conventional fixed parameters PSS within reactive power control loop of DFIG rotor side converter has a positive damping contribution for a wide range of operating conditions. Furthermore, the results clearly show that DFIG based wind farms equipped with the proposed farm level PSS can damp power system oscillations more effectively than SGs PSS. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents an application of microwave near-field technique into the cement-based material, which is designated as engineered cementitious mortar in civil material engineering. Parallel measurements of microwave near-field probing and conventional compression test were undertaken. The objective of this interdisciplinary research is to develop correlations of compressive strengths with electrical properties at microwave frequencies. First-order exponential regressions were applied to the measurement data. Simple yet accurate correlation models have been developed for strength prediction. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2696-2699, 2016 [ABSTRACT FROM AUTHOR]

This study analyses the effect of replacing existing synchronous generators (SGs) equipped with power system stabilisers (PSS) by doubly fed induction generator (DFIG) based wind farms on the damping of power system oscillations in a multi‐machine power system. A power system stabiliser was designed to enhance the capability of DFIG to damp power systems oscillations. The validity and effectiveness of the proposed controller are demonstrated on the widely used New England 10‐machine 39‐bus test system that combines conventional SGs and DFIG based wind farms using eigenvalue analysis and non‐linear simulation. The non‐linear simulation is used to demonstrate how the damping contribution of DFIG based wind farms is affected by different operating conditions within the same wind farm and stochastic wind speed behaviour. The results show that installing conventional fixed parameters PSS within reactive power control loop of DFIG rotor side converter has a positive damping contribution for a wide range of operating conditions. Furthermore, the results clearly show that DFIG based wind farms equipped with the proposed farm level PSS can damp power system oscillations more effectively than SGs PSS. [ABSTRACT FROM AUTHOR]

Microwave noninvasive and evaluation techniques have shown to be promising for characterization of cement-based materials (CBMs). In the construction industry, the determination of initial water-to-cement (w/c) ratio and cure-state monitoring of early-age CBMs are still challenging tasks. In this paper, measurement results of monitoring of reflection coefficients, electrical conductance and susceptance of early-age concrete, and mortar specimens with different w/c ratios and constituent ratios are presented. The comparative measurements are conducted using a microwave near-field noninvasive testing technique at two frequency bands, namely, R-band (1.7 – 2.6 GHz) and X-band (8.2 – 12.4 GHz). Statistical analysis and exponential curve fitting have been performed on the temporal measurements of early-age (a few first days) CBMs. The results demonstrated that the dynamic ranges, the initial values, and the initial slopes of measurement curves can be used for cure-state monitoring, hydration rates prediction, and initial w/c ratio determination. [ABSTRACT FROM PUBLISHER]

In view of the known problems of parameter sensitivity, local optimum, and slow convergence in the ant colony optimization (ACO), we aim to improve the performance of the ACO. To solve the traveling salesman problem (TSP) quickly with accurate results, we propose a fully parallel ACO (FP-ACO). Based on the max–min ant system (MMAS), we initiate a compensation mechanism for pheromone to constrain its value, guarantee the correctness of results and avoid a local optimum, and further enhance the convergence ability of ACO. Moreover, based on the compute unified device architecture (CUDA), the ACO is implemented as a kernel function on a graphics processing unit (GPU), which shortens the running time of massive iterations. Combined with the roulette wheel selection mechanism, FP-ACO has powerful search capabilities and is committed to obtaining better solutions. The experimental results show that, compared with the effective strategies ACO (ESACO) that runs on CPU, the speed-up ratio of the proposed algorithm reaches 35, and the running time is less than that of the max–min ant system-roulette wheel method-bitmask tabu (MMAS-RWM-BT) that runs on GPU. Furthermore, our algorithm outperforms the other two algorithms in the speed-up ratio and less runtime, proving that the proposed FP-ACO is more suitable for solving TSP. [ABSTRACT FROM AUTHOR]

This communication presents a 2\,\times\,2 circularly polarized (CP) antenna array composed of H-shaped patches. The uniqueness of this CP array is its feeding network, where state-of-the-art metamaterial transmission lines (MMLs) are built to obtain the required quadrature phases. Experimental results show that the feed network has excellent power distribution and progressive phases over a wide bandwidth. As a consequence, the MML-based array exhibits excellent performance, viz. 85% impedance bandwidth (SWR\ \leq 2), 89% axial-ratio (3-dB) bandwidth, 80% efficiency at a center frequency of 2.5 GHz and 55% pattern bandwidth with a criterion of 8-dBic gain level. The axial-ratio bandwidth is validated with cross-polar discriminations obtained from radiation patterns. [ABSTRACT FROM PUBLISHER]

This article presents a metamaterial transmission-line-based triple-feed network, which is meant for wideband circularly polarized antennas. The feed network itself is capable of an octave bandwidth, from 1.6 to 3.2 GHz, for an amplitude error of ±0.5 dB and phase error of ±10°. Prototype of a triangular slot antenna was implemented to validate the proposed triple-feed network. The measurement results show that the entire antenna has an impedance bandwidth (standing-wave-ratio ≤ 2) of 73.4%, whereas the 3-dB axial-ratio bandwidth is obtained at 27%. Bidirectional beam patterns with opposed polarization senses have been observed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1419-1423, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26821 [ABSTRACT FROM AUTHOR]

Purpose: The prevalence of obesity has been increasing in the United States. We set out to investigate the use of pharmacologic and non-pharmacologic therapy for the treatment of obesity in recent years. Methods: We included 2630 men and 2702 women who took part in the National Health and Nutrition Examination Survey from 2007 to 2008. We analyzed their demographic and anthropometric data and their weight and drug history. Results: A total of 45.9% of men and 45.0% of women were candidates for treatment (body mass index ≥30 kg/m2, or ≥27 kg/m2 with risk factors). Among these participants, 85.1% considered themselves overweight, 90.1% would like to lose weight, 61.9% had dietary changes, 36.5% exercised, 3.7% took nonprescription drugs, and 2.2% took prescription drugs to control weight during the preceding year. During the preceding month, 0.5% and 0.1% of participants were taking phentermine and orlistat, respectively. There were no participants on sibutramine. Conclusions: Although obesity is highly prevalent, only a small percentage of obese Americans are on anti-obesity medication. The withdrawal of sibutramine would have minimal impact on the general population. There is a need for more lifestyle changes in the majority of obese individuals. [Copyright &y& Elsevier]

This article presents a metasurfaced patch antenna in which the metasurface acts as a superstrate/cover placed atop a 2.45-GHz patch antenna, at a small distance. The metasurface is a Mu-near-zero (MNZ) type, which gives a near-zero index of refraction. The MNZ metasurface consists of 4 × 4 double-closed-loop resonators printed on a thin FR4 dielectric slab. The proposed antenna is low-cost and low-profile, having overall dimensions of 0.86 λ × 0.86 λ × 0.07 λ. The simulation and experimental results confirm that the metasurfaced antenna not only has simultaneous enhancements on broadside gain and bandwidth, but also improves antenna efficiency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:529-532, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26574 [ABSTRACT FROM AUTHOR]

Disease activity 6 months before pregnancy of patients with systemic lupus erythematosus (SLE) associated with adverse maternal and fetal outcomes is not well studied. The aim of the study was to identify predictors of adverse maternal and fetal outcomes in pregnant SLE patients, based on patients’ background characteristics, clinical and laboratory data 6 months before pregnancy. Of 103 pregnancies, 55 pregnancies in 39 SLE patients were investigated. Clinical and laboratory data were recorded at regular intervals from 6 months before conception to 1 year after delivery. Primary outcomes included the predictors of combined adverse maternal and fetal outcomes. Potential explanatory variables included demographic, clinical and laboratory data 6 months before conception. Using logistic regression, history of nephritis (p = 0.001, odds ratio [OR] 13.3, 95% confidence interval [CI] 2.7–65.1) and a high SLE Disease Activity Index (SLEDAI) score 6 months before pregnancy (p = 0.015, OR 1.7, 95% CI 1.1–2.7) were associated with combined adverse maternal outcome, whereas flare during pregnancy (p = 0.003, OR 29.3, 95% CI 3.1–273.1) predicted combined adverse fetal outcome. The area under the curve for SLEDAI score of combined maternal outcome was 0.73 (95% CI 0.58–0.87). The optimal cut-off point according to the receiver operating characteristic curve was 4, with a sensitivity of 64% and a specificity of 75%. In conclusion, a history of nephritis or a SLEDAI score of 4 or more in SLE patients 6 months before conception predicts adverse maternal outcomes, while disease flare during pregnancy predicts adverse fetal outcomes. Pregnancies should be delayed until the disease has been in remission for 6 months. [ABSTRACT FROM AUTHOR]

A wideband H-shaped patch antenna for circular polarization is described. By incorporating a long probe inside a substantial high cavity (\sim 0.26\lambda), a circularly polarized (CP) antenna in broadside direction is achieved. The horizontal arm of the probe is implemented by means of a printed monopole that is diagonally coupled to a small H-shaped copper plate. The CP antenna features a wide operational bandwidth of 19.4%. The maximum gain and the efficiency of this small antenna are recorded as >5 dBic and >80%, respectively, across the bandwidth. The dimension of the H-shaped patch is 0.3\lambda\times 0.3\lambda whereas the ground plane size is 1.8\lambda\times 1.8\lambda. [ABSTRACT FROM PUBLISHER]

An application of particle swarm optimization (PSO) for wideband patch antenna design is presented in this article. A PSO kernel is built on a MATLAB-driven MoM-based EM simulator FEKO. The chosen antenna geometry in this study is the E-shaped patch but excited by an L-probe feed. Ten geometrical parameters are optimized simultaneously with the use of a single-objective: impedance bandwidth broadening. The desired center frequency of this ceiling mounted WLAN (IEEE 802.11a/n) antenna is set at 5.5 GHz with butterfly beam operation. E-shaped patch geometry of higher order mode is obtained from the PSO-EM optimizer. The simulated results are verified by the experimental results that a ∼3.5 dBi gain at the elevation angles of ±36° and a >50% of 10-dB return-loss bandwidth are obtained at the price of high cross-polarization levels. This suggests that a multiobjective particle swarm optimization should be used for the wideband antenna design in the future study. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 702–706, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25016 [ABSTRACT FROM AUTHOR]

With the advent of commercial image-guided radiotherapy, daily correction of the setup uncertainty is feasible. It is beneficial to understand the dependence of the probability density function (pdf) of the corrected setup variation on the action level, localization uncertainty and re-positioning uncertainty so that an appropriate action level is used. Also, that pdf can be used in treatment planning to incorporate setup variation directly in the planning process to generate treatment plans more robust to setup variations. We have found an analytical expression of the pdf of the corrected setup variation assuming normal distributions for the uncertainties. Using the second moment of that pdf as a metric, we have explored the dependence of the metric on the action level for the following cases: (1) the uncertainties in measurement and re-positioning are less than the initial setup uncertainty, (2) the uncertainties in measurement and re-positioning are on the order of the initial setup uncertainty, (3) the uncertainty in measurement is the least and (4) the uncertainty in re-positioning is the least. An optimal action level exists in case 3. We have also found that an action level of \sqrt {\vphantom{A^A}\smash{\hbox{$\mu _p ^2 + \sigma _p ^2 + \sigma _m ^2$}} } works well in practice where mp is the mean of the re-positioning uncertainty, sp is the standard deviation of the re-positioning uncertainty and sm is the standard deviation of the localization uncertainty. In typical clinical situations, the distribution of the corrected setup variation can be closely approximated by a normal distribution. [ABSTRACT FROM AUTHOR]

This article presents experimental investigation on the effect of layer displacements for an X-band circularly polarized patch antenna. Experimental results demonstrate that such antenna makes use of high-low-low dielectric materials combination has tolerant characteristics not just on the impedance bandwidth but also the CP bandwidth to withstand layer displacements. Based on the measured bandwidths, displacement limits are located as 0.067λo for the entire x-y plane. Also, gain variations are found to be insignificant. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2047–2050, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22562 [ABSTRACT FROM AUTHOR]

Orthokeratology attempts to reduce myopia by remoulding the corneal shape with contact lenses. A recent resurgence is predicated on new contact lens designs with a prefigured back contact surface and higher oxygen transmissibility. This Clinical Controversy presents an analysis of the risk factors associated with orthokeratology and its suitability for children, followed by commentaries from specialists who have an interest in the method. Some state that there is a lack of data on relative risks of corneal infection and that there is a need for large-scale randomized controlled studies; however, opinion is expressed by others that orthokeratology is a clinically safe procedure using modern lenses. It is noted that the physiological and biophysical bases of orthokeratology are virtually unknown, and further research on the human cornea is indicated to scientifically establish the safety of orthokeratology. Prospective patients, and their parents in the case of children, should be fully informed of the risks. [ABSTRACT FROM AUTHOR]

In this communication, we present a high-performance circularly polarized (CP) stacked electromagnetically coupled patch antenna and its subarray at X band. In addition to low boresight axial-ratios, the subarray has measured 10-dB impedance and 3-dB axial-ratio bandwidths of 25.6% and 23.5% respectively as compared to the measured 20.2% and 8.0% for a single element. The mutual coupling for this element is shown to be lower than other reported stacked patch antennas and obtained a gain (>10 dbic) bandwidth of 23.5%. The calculated antenna efficiency is 89% around center frequency for the single element whereas the subarray has an overall efficiency of > 71% (-1.5 dB) over 21% bandwidth. [ABSTRACT FROM AUTHOR]

Our aim was to examine secondary image formation in the anterior segment caused by peripheral light focusing (PLF) in the human cornea, and in particular the crystalline lens. Non-sequential ray-tracing (OptiCAD) was applied to an anatomically based human eye model, which incorporates a gradient index crystalline lens. For analysis of the limbal effect, we varied the incident angle from 100 to 122°, while for the crystalline lens effect, the incident angle was varied from 60 to 90°. The corneal shapes studied included central radii from 7.4 to 8.2 mm with a range of shape factors. In each case, we computed the peak and average intensities, and the area of exposure at the limbus or lens periphery. The computation was repeated with a previous model eye for comparison. For the limbal effect, a peak intensity gain of ×22.5 was found at an incident angle of 104° which compares well with previous results. The average intensity gain at this angle was ×7.5 over an area of 0.23 mm2. Steeper corneal curvature produced a greater PLF effect. For the crystalline lens effect, maximum UVA (365 nm) intensity gain peaked at ×8.6 at 84° with average intensity gain of ×2.3. The area of UVA exposure peaked at 4.7 mm2 at 70°. A relatively wide range (30°) of incident angles produced peak PLF gains of ×3 or more in the lens. Significant focusing of light is directed to the nasal limbus, and to a lesser extent to the crystalline lens over a broad range of incident angles. PLF in the nasal cornea is reduced by an order of magnitude when a UV-blocking soft contact lens is used. The concentration levels and intraocular sites of PLF action on UV and visible light suggest a new mechanism of phakic dysphotopsia and lens phototoxicity. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the effect of the offset patch and layer misalignments on the broadband characteristics of a two-layer, electromagnetically coupled, stacked patch antenna with airgap at the X-band. Linear and angular displacements of the parasitic patch on the dielectric layer are considered for the experimental study. The measured results show very robust impedance characteristics of the proposed antenna element against layer misalignment. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 345–348, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11056 [ABSTRACT FROM AUTHOR]

A broadband high-gain single-feed cross-aperture coupled patch antenna is presented in this paper. The measured results confirm that the antenna is capable of a 14.4% impedance bandwidth (VSWR ≤ 2), 3% of 3-dB axial-ratio bandwidth, and 17.4% of gain (>8 dBic) bandwidth with a mean gain level of 9.3 dBic. The techniques for obtaining high gain and broad impedance bandwidth as well as the effects on aperture size are discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 283–286, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10895 [ABSTRACT FROM AUTHOR]

An experimental study has been performed to determine the heat transfer characteristics of round and slot premixed butane/air flame jets, which were impinging upwards normally on a horizontal rectangular plate. Effect of the burner geometry on the heat transfer coefficient at the jet/plate interface, with the variation of Reynolds number and air/fuel equivalence ratio, has been examined. Round and slot burner nozzles with the same cross-sectional area were tested at a constant nozzle-to-plate distance of 2d. The Reynolds number was selected to range from 1,000 to 1,700, in order to produce a laminar flow. The air/fuel equivalence ratio was extended from 0.95 to 1.3 to produce fuel-lean, stoichiometric, and fuel-rich flames. When compared to the round jet, the slot jet provided more uniform heat flux on the impingement plate, but the peak heat flux was not so concentrated. The slot jet produced different heat flux distributions along the length and width of the impingement plate, and the average heat flux was higher along the direction of the slot width (i.e., the plate width) in the present study, especially when the Reynolds number or the equivalence ratio was increased. The present study provides more information and a comparison between the heat transfer characteristics of round and slot premixed impinging flame jets utilizing a butane/air mixture. Such reports have rarely been reported in the literature. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel frequency beam-scanning leaky-wave antenna (LWA) based on a composite half-mode substrate integrated waveguide/spoof surface plasmon polariton (HMSIW/SSPP) waveguide. The new composite HMSIW/SSPP waveguide is accomplished by embedding periodical symmetric subwavelength grooves on both copper surfaces of the HMSIW, which owns flexible transmission characteristics attributed to its features from both HMSIW and SSPP. The conversion of propagating slow-wave mode to radiation mode is devised by a double-sided symmetric sinusoidal modulation method with a π/2 displacement between the top- and bottom-surface. This double-sided modulation method not only offers a compact structure but also effectively eliminates the open stopband. A prototype of the proposed antenna is fabricated and measured to verify the predicted performance from simulation. Experimental results show that the proposed antenna achieves a continuous wide scanning range of 125° from backward to forward for lateral unidirectional radiation with an average peak gain level of 9.1 dBi from 6.3 to 9.7 GHz. And the compact antenna volume of 0.40 × 8.0 × 0.013 λ 0 3 offers a well scanning rate (36.8°/GHz) and a very high gain value per unit volume (219 dBi/ λ 0 3). [ABSTRACT FROM AUTHOR]

In this paper, we present a novel frequency beam-scanning leaky-wave antenna (LWA) based on a composite half-mode substrate integrated waveguide/spoof surface plasmon polariton (HMSIW/SSPP) waveguide. The new composite HMSIW/SSPP waveguide is accomplished by embedding periodical symmetric subwavelength grooves on both copper surfaces of the HMSIW, which owns flexible transmission characteristics attributed to its features from both HMSIW and SSPP. The conversion of propagating slow-wave mode to radiation mode is devised by a double-sided symmetric sinusoidal modulation method with a π/2 displacement between the top- and bottom-surface. This double-sided modulation method not only offers a compact structure but also effectively eliminates the open stopband. A prototype of the proposed antenna is fabricated and measured to verify the predicted performance from simulation. Experimental results show that the proposed antenna achieves a continuous wide scanning range of 125° from backward to forward for lateral unidirectional radiation with an average peak gain level of 9.1 dBi from 6.3 to 9.7 GHz. And the compact antenna volume of 0.40 × 8.0 × 0.013 λ 0 3 offers a well scanning rate (36.8°/GHz) and a very high gain value per unit volume (219 dBi/ λ 0 3). [ABSTRACT FROM AUTHOR]

A cost‐effective solution for the performance enhancement of circularly polarised array antennas by using a thin metasurface is proposed. The array is considered as reconfigurable, where an antenna engineer can arbitrarily add the metasurface onto the original array according to application requirements. Once added, the new array forms a subwavelength cavity having a compact form factor of 1.63λo × 1.63λo × 0.07λo at 2.45 GHz. The array antenna is demonstrated to have remarkable enhancement on its performance metrics including boresight gain (12.8 dBic), axial‐ratio bandwidth (46.5%) and 10 dBic gain bandwidth (24.4%). More interestingly, a sidelobe suppression level of 4.4 dB is achieved. [ABSTRACT FROM AUTHOR]

Viscous effects on the excitation of cross-waves in a semi-infinite box of finite depth and width are considered. A formalism using matched asymptotic expansions and an improved method of computing the solvability condition is used to derive the relative contributions of the freesurface, sidewall, bottom, and wavemaker viscous boundary layers. This analysis yields an expression for the damping coefficient previously incorporated on heuristic grounds. In addition, three new contributions are found: a viscous detuning of the resonant frequency, a slow spatial variation in the coupling to the progressive wave, and a viscous correction to the wavemaker boundary condition. The wavemaker boundary condition breaks the symmetry of the linear neutral stability curve at leading order for many geometries of experimental interest. [ABSTRACT FROM AUTHOR]

This article introduces an ultra-compact fourway quadrature power splitter (4W-QPS) based on a novel transmission-line compression technique called double-path zigzag microstrip line (DP-ZML). Detailed design techniques with modular approach are disclosed for the state-of-the-art 5G low-band applications. The theoretical predictions are verified with experimental results through a fabricated prototype that operates from 696.55 to 876.03 MHz with >15 dB return-losses and isolations, and 90°±4° quadrature phase between adjacent outputs. The compact size of this 4W-QPS is achieved at 0.21λgx0.21λg at a center frequency of 786 MHz. [ABSTRACT FROM AUTHOR]

This article reports a modification of two-strip monopole antenna, which was an undergraduate final year project. The modified antenna uses a thicker substrate when compared with the original design while maintaining the monopole radiation characteristics at the WiFi frequency bands of 2.4 and 5 GHz. One of the significant improvements of the antenna is the inclusion of the mobile WiMAX frequency band at 3.5 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2884–2886, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24801 [ABSTRACT FROM AUTHOR]

Here we present a novel linear circularly polarized (CP) antenna array using non-identical CP elements, where the Chinese character-shaped patches are employed to form a linear array. Namely, the single-feed CP Zhong-, Guo-, and Meng-shaped patch antennas have collected to form a three-element antenna array. A one-to-three power splitter with equal amplitudes but unequal phase-shifts at its output ports was deliberated as the feed network for the linear array. The challenge of this antenna array design is the appropriate phase excitation to the non-identical radiating elements so that the CP gain and operating bandwidth can meet the requirements of the application(s), in which we undertook an in-depth investigation. A proof-of-concept design example for 2.4 GHz wireless local area network (WLAN, IEEE 802.11b/g/n) has demonstrated the effectiveness of the combination technique on the non-identical CP antenna elements. The simulation, in combination with experimental validation, obtained an on-axis 3-dB axial-ratio bandwidth from 2.28 to 2.59 GHz (12.7%), whereas a broadside gain of 9 dBic at 2.5 GHz and an overall efficiency of 82% were recorded within the bandwidth. [ABSTRACT FROM AUTHOR]

This article presents a novel single-feed circularly polarized patch antenna for dual-band (2.6 and 3.4 GHz) applications. Details of the design procedure and design considerations of the proposed antenna are described. The novelties of the proposed antenna are counted by (i) a meaningful Jia -shaped patch used as the primary radiator; (ii) a 3D L -shaped feeding probe used to excite the stacked patches so that the near degenerate-modes are excited at the desired dual band; (iii) down-tilt beams achieved that are particularly suitable for wall-mount base-stations. The measured 3-dB axial-ratio bandwidths are 2.41–2.61 GHz and 3.25–3.42 GHz, where the maximum gains are recorded as 7.3 and 6.3 dBic, respectively. Methods for the adjustment of band ratio down to 1.18 are discussed. The overall antenna size is 100 × 100 × 12.8 mm3. [ABSTRACT FROM AUTHOR]

Junior researchers can be abused and bullied by unscrupulous senior collaborators. This article describes the profile of a type of serial abuser, the White Bull, who uses his academic seniority to distort authorship credit and who disguises his parasitism with carefully premeditated deception. Further research into the personality traits of such perpetrators is warranted. [ABSTRACT FROM AUTHOR]

Aim: To review the pattern and characteristics of snakebites in children in rural Hong Kong. Methods: A retrospective chart review was conducted. Results: Seven cases of snakebite in children were reported. Eighty-six percent of the victims were male, and the majority of bites (86%) occurred on the left extremities. Green pit vipers ( Trimeresurus albolabris ) accounted for most of the snakebites. Local symptomatology was common. Swelling, pain and fang marks were documented in all cases. A mildly deranged clotting profile was found in 70% of patients. There was no incidence of systemic symptoms, cardiopulmonary complications or compartment syndrome. Victims arrived at the hospital at a median (range) time of 40 (10-70) min since the snakebite. Only one child received antivenin owing to severe progressive local symptoms under intensive care monitoring. The median hospital stay of the patients was 4 d. The hands and feet of adolescent boys ( n = 6) seem to be particularly prone to being bitten. Conclusion: Children should be discouraged to play in areas where snakes may hide, especially in the evening in summer to autumn. They should wear protective footwear. [ABSTRACT FROM AUTHOR]

A dual-polarized wideband omnidirectional ceiling antenna with low gain variations (GVs) for 2G/3G/LTE/5G sub-6 GHz indoor applications is presented. The vertical-polarized (VP) antenna element that is arranged in the center is composed of a pair of orthogonal semicircular plates and a top-loaded circular brass disk, whereas the horizontal-polarized (HP) antenna element is comprised of four printed dipoles with truncated corners, four arc-shaped parasitic patches around the dipoles, and a 1-to-4 power divider feeding network on the bottom. The feeding network with the “hook”-shaped stubs cooperates with the slot between the adjacent printed dipoles to improve the isolation between the VP and HP antenna elements. Furthermore, the top-loaded circular brass disk, the four arc-shaped parasitic patches, and two pairs of extended strips printed along the ±45° direction are used to reduce the GVs but broaden the operating bandwidths. Experimental results demonstrate that a wide overlapped frequency bandwidth of 74.9% (1.66–3.65 GHz) with an excellent port isolation (≥40 dB) is achieved for the aforesaid application scenarios. [ABSTRACT FROM AUTHOR]

In this communication, a dual-polarized filtering magneto-electric dipole (FMED) antenna and arrays are proposed for 5G n258 (24.25–27.5 GHz) operations. The FMED antenna was devised to incorporate filtering mechanisms using a built-in substrate integrated waveguide (SIW)-based filter plus slot-and-notch etching on the dipole element. As such, lower and upper radiation cutoffs and nulls were produced and tuned, independently. To overcome the problem of “high selectivity” of a filtering antenna that has not been correctly quantified and thus has no comparison, a new skirt measure metric named as radiation suppression index is initiated here. Design steps of the FMED element and novel feeding techniques are elaborated, where the SIW-based series-parallel slot-coupled feeders and the slot-coupled differential power divider were conceived for large-size array, to combat with the insertion losses. A prototype of 4 $\times $ 4 FMED array was implemented and tested for experimental verification. A high gain of 16.8 dBi ± 1.4 dBi with a 3 dB gain bandwidth of 24–27.7 GHz and a radiation efficiency of 78% were accomplished. [ABSTRACT FROM AUTHOR]

A cost-effective solution for the performance enhancement of circularly polarised array antennas by using a thin metasurface is proposed. The array is considered as reconfigurable, where an antenna engineer can arbitrarily add the metasurface onto the original array according to application requirements. Once added, the new array forms a subwavelength cavity having a compact form factor of 1.63λo × 1.63λo × 0.07λo at 2.45 GHz. The array antenna is demonstrated to have remarkable enhancement on its performance metrics including boresight gain (12.8 dBic), axial-ratio bandwidth (46.5%) and 10 dBic gain bandwidth (24.4%). More interestingly, a sidelobe suppression level of 4.4 dB is achieved. [ABSTRACT FROM AUTHOR]

This article presents a miniaturized Wilkinson power divider (WPD) for dual‐band applications using a novel planar transmission line. The new planar line fully uses the substrate area and aims to take place of the quarter‐wave transformers of the traditional WPD. Namely, the copper foil on the both sides of the substrate were used to composite microstrip line (ML) and a coplanar waveguide (CPW) line. The transitions of the ML and CPW were achieved by a copper via. The WPD has realized a miniaturization at 0.9 and 2.9 GHz with a small footprint of 12.92 × 6.8 mm2.The simulated results are verified by measured results to show that the isolations within the dual band are both less than −20 dB, the reflection coefficients are both less than −10 dB, whereas the insertion loss are both less than 3.10 dB in 0.8 to 1.0 GHz and 2.8 to 3.0 GHz bands. [ABSTRACT FROM AUTHOR]