A Multidisciplinary Approach toward CMOS Capacitive Sensor Array for Droplet Analysis

This paper introduces an innovative method for the analysis of alcohol-water droplets on a CMOS capacitive sensor, leveraging the controlled thermal behavior of the droplets. Using this sensing method, the capacitive sensor measures the total time of evaporation (ToE), which can be influenced by the droplet volume, temperature, and chemical composition. We explored this sensing method by introducing binary mixtures of water and ethanol or methanol across a range of concentrations (0-100%, with 10% increments). The experimental results indicate that while the capacitive sensor is effective in measuring both the total ToE and dielectric properties, a higher dynamic range and resolution are observed in the former. Additionally, an array of sensing electrodes successfully monitors the droplet-sensor surface interaction. However practical considerations such as the creation of parasitic capacitance due to mismatch, arise from the large sensing area in the proposed capacitive sensors and other similar devices. In this paper, we discuss this non-ideality and propose a solution. Also, this paper showcases the benefits of utilizing a CMOS capacitive sensing method for accurately measuring ToE.

[Research advances in clinical biochemical analysis systems based on microfluidic driving and control technique]

Microfluidic techniques have the features of high throughput, low consumption, as well as ease of miniaturization, integration, and automation, thus emerging as a feasible solution to cost-effective clinical biochemical analysis. Various clinical biochemical analysis systems based on the microfluidic technique, with different driving and control methods, are introduced in this article, in addition to commercially available microfluidic biochemical analysis instruments. The characteristics of these systems are comprehensively reviewed.

Rotary and High-Pressure Nozzle Spray Plume Droplet Analysis For Aerially Applied Mosquito Adulticides: Laser Diffraction Characterization

The droplet spectrum of a mosquito adulticide spray plume determines its ability to drift through the target area, impinge on the mosquito, deliver a toxic dose, and the risk of environmental contamination. This paper provides data on droplet spectra produced from 6 nozzles in a high-pressure nozzle spray system and 5 rotary nozzle systems for common mosquito adulticides. Spray plume spectra were measured by laser diffraction. High-pressure nozzles were evaluated at pressures ranging from 500 psi to 6,000 psi. Rotary nozzles were evaluated at rotational speeds ranging from 500 rpm to 24,000 rpm. Measurements were made at wind speeds of 129 km/h (80 mph) to 225 km/h (140 mph). Adulticides included were Fyfanon^®, Aqua-Reslin^®, Dibrom^®, Duet^®, Permanone^®, and the inert mineral oil, Orchex^® 796. High-pressure nozzles produced spray plumes within the US Environmental Protection Agency (EPA) label requirements for all configurations tested except for one at a wind speed of 225 km/h, BETE^® MW125. Air speed had no significant effect on the spray plume volume median diameter (Dv_(0.5)) at the speeds tested with Fyfanon^®. The spray plume 90% drop volume diameter (Dv_(0.9)) significantly decreased, 13% at the higher wind speed of 225 km/h. Drop size was inversely related to pressure. Dilution of the product formulations increased the Dv_(0.5) of the spray plume but it did not exceed the label requirements. For the PJ15 nozzle, orientation of the nozzle into the wind of up to 135° showed a significant increase in Dv_(0.5) at 500 psi, 750 psi, and 1,500 psi. The Dv_(0.5) varied <5 μm over the 3 angles examined for any specific pressure. Rotary nozzles produced spray plumes within the EPA label requirements for all test configurations examined. Air speed had no significant effect on Dv_(0.5) or Dv_(0.9) of the plume at speeds tested with Fyfanon for the ASC A20 nozzle. The rotary AU5000 nozzle using Orchex 796 produced plumes of larger drops in all configurations than any of the rotary nozzles of similar configurations using active ingredient formulations and within EPA label requirements.

Monitoring the evaporation of fluids from fiber-optic micro-cell cavities

Fiber-optic sensors provide remote access, are readily embedded within structures, and can operate in harsh environments. Nevertheless, fiber-optic sensing of liquids has been largely restricted to measurements of refractive index and absorption spectroscopy. The temporal dynamics of fluid evaporation have potential applications in monitoring the quality of water, identification of fuel dilutions, mobile point-of-care diagnostics, climatography and more. In this work, the fiber-optic monitoring of fluids evaporation is proposed and demonstrated. Sub-nano-liter volumes of a liquid are applied to inline fiber-optic micro-cavities. As the liquid evaporates, light is refracted out of the cavity at the receding index boundary between the fluid and the ambient surroundings. A sharp transient attenuation in the transmission of light through the cavity, by as much as 50 dB and on a sub-second time scale, is observed. Numerical models for the transmission dynamics in terms of ray-tracing and wavefront propagation are provided. Experiments show that the temporal transmission profile can distinguish between different liquids.

X-ray speckle visibility spectroscopy in the single-photon limit

The technique of speckle visibility spectroscopy has been employed for the measurement of dynamics using coherent X-ray scattering. It is shown that the X-ray contrast within a single exposure can be related to the relaxation time of the intermediate scattering function, and this methodology is applied to the diffusion of 72 nm-radius latex spheres in glycerol. Data were collected with exposure times as short as 2 ms by employing a resonant shutter. The weak scattering present for short exposures necessitated an analysis formalism based on the spatial correlation function of individual photon charge droplets on an area detector, rather than the usual methods employed for intensity correlations. It is demonstrated that this method gives good agreement between theory and experiment and thus holds promise for extending area-detector-based coherent scattering methods to the study of faster dynamics than previously obtainable.