Human exposure to pathogenic viruses in environmental waters results in a significant global disease burden. Current microbial water quality monitoring approaches, mainly based on fecal indicator bacteria, insufficiently capture human health impacts posed by pathogenic viruses in water. The emergence of the 'microbiome era' and high-throughput metagenome sequencing has led to the discovery of novel human-associated viruses, including both pathogenic and commensal viruses in the human microbiome. The discovery of novel human-associated viruses is often followed by their detection in wastewater, highlighting the great diversity of human-associated viruses potentially present in the water environment. Novel human-associated viruses provide a rich reservoir to develop viral water quality management tools with diverse applications, such as regulating wastewater reuse and monitoring agricultural and recreational waters. Here, we review the pathway from viral discovery to water quality monitoring tool, and highlight select human-associated viruses identified by metagenomics and subsequently detected in the water environment (namely Bocavirus, Cosavirus, CrAssphage, Klassevirus, and Pepper Mild Mottle Virus). We also discuss research needs to enable the application of recently discovered human-associated viruses in water quality monitoring, including investigating the geographic distribution, environmental fate, and viability of potential indicator viruses. Examples suggest that recently discovered human pathogens are likely to be less abundant in sewage, while other human-associated viruses (e.g., bacteriophages or viruses from food) are more abundant but less human-specific. The improved resolution of human-associated viral diversity enabled by metagenomic tools provides a significant opportunity for improved viral water quality management tools.
Abstract-In this paper, a novel power divider integrated with substrate integrated waveguide (SIW) and defected ground structures (DGS) techniques is proposed to provide both power dividing and filtering functions. The SIW technique holds advantages of low profile, low-lost, mass-production, easy fabrication and fully integration with planar circuits. By integrating with defected ground structures (DGS) technique, the size and cost of system can be effectively reduced as the proposed power divider has a function of filtering which leads to reduction of one filter. In order to verify the design approach, the proposed power divider with equal power divisions at the center frequency of 8.625 GHz is fabricated and measured. The measured results demonstrate that the insertion loss is less than 1.2 dB and the input return loss less than 16 dB across the bandwidth of 1.4 GHz (FBW is 16%). Moreover, the imbalances of the amplitude and phase are less than 0.3 dB and 0.5 degree, respectively.
Ultrasonic motor operation relies on high-frequency vibration of a piezoelectric vibrator and interface friction between the stator and rotor/slider, which can cause temperature rise of the motor under continuous operation, and can affect motor parameters and performance in turn. In this paper, an integral model is developed to study the thermal–mechanical–electric coupling dynamics in a typical standing wave ultrasonic motor. Stick–slip motion at the contact interface and the temperature dependence of material parameters of the stator are taken into account in this model. The elastic, piezoelectric and dielectric material coefficients of the piezoelectric ceramic, as a function of temperature, are determined experimentally using a resonance method. The critical parameters in the model are identified via measured results. The resulting model can be used to evaluate the variation in output characteristics of the motor caused by the thermal–mechanical–electric coupling effects. Furthermore, the dynamic temperature rise of the motor can be accurately predicted under different input parameters using the developed model, which will contribute to improving the reliable life of a motor for long-term running.
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