Performance comparison of illumination methods for finger-vein imaging and liveness detection

Microsystem Technologies - Four laser illumination methods based on a diffuser, concave lens, quasi-static microelectromechanical system (MEMS) scanner, and resonant MEMS scanner, were evaluated...     

Flash spray characteristics of a coal-liquid carbon dioxide slurry

Liquid carbon dioxide (LCO₂) could potentially be utilized in coal gasification plants for effectively transporting coal particles, replacing conventional carriers such as water (H₂O), particularly in wet-fed gasifiers. However, it is essential to understand the atomization behavior of LCO₂ leaving an injector nozzle under both coal-free and coalfed conditions. We examined the atomization behavior of a coal-LCO₂ slurry during the throttling process. The injector nozzle was mounted downstream of a high-pressure spray system. The effect of upstream pressure on flash atomization and devolatilization behavior was presented. Compared with the coal-LCO₂ mixture, the spray pattern of the coal-water mixture was significantly different, since it evidenced a Rayleigh-type breakup mode. This difference indicates that the coal-water slurry did not transport the coal as effectively as the coal-LCO₂ slurry.     

Biodiesel combustion,emissions and emission control

The use of biodiesel is rapidly expanding around the world, making it imperative to fully understand the impacts of biodiesel on the diesel combustion process, pollutant formation and exhaust aftertreatment. Because its physical properties and chemical composition are distinctly different from conventional diesel fuel, biodiesel can alter the fuel injection and ignition processes whether neat or in blends. As a consequence, the emissions of NO_x and the amount, character and composition of particulate emissions are significantly affected. In this paper, we survey observations from a spectrum of our earlier studies on the impact of biodiesel on diesel combustion, emissions and emission control to provide a summary of the challenges and opportunities that biodiesel can provide.     

Functionalized Carbon Dots on Graphene as Outstanding Non‐Metal Bifunctional Oxygen Electrocatalyst

Carbon‐based bifunctional electrocatalysts for both oxygen reduction and evolution reactions are potentially cost‐effective to replace noble metals in energy devices such as fuel cells, metal–air batteries, and photoelectrochemical converters, but enrichment of active sites holds the key to efficiency. Here, graphene frameworks with heteroatom‐doped carbon dots (CDs) are developed via a hydrothermal route followed by pyrolysis. The CDs are rationally prepared with careful selection of heteroatoms, embedded on the substrate to provide enriched active sites. Structural characterizations (e.g., transmission electron microscopy and X‐ray photoelectron spectroscopy) reveal the successful addition of CDs with nitrogen and sulfur species. Especially, a heat‐treated N,S codoped sample, NS‐CD@gf_a900, exhibits the optimum oxygen electrocatalysis, even closer to noble‐metal counterparts, as a result of the effect of active sites of the CDs and the synergistic behavior of N and S. Considering the importance of size and dopants of the material, this approach not only suggests a straightforward preparation route of nanocarbons, but also appoints the utilization of a new class of non‐metal species as efficient oxygen electrocatalysts.     

Label-free electrochemical impedance spectroscopy using a micro interdigitated electrode inside a PCR chip for real-time monitoring

Conventional real-time PCR using fluorescence detection requires expensive optical detection systems with fluorescence labeling. To simplify this PCR system, we proposed an electrochemical impedance spectroscopy (EIS) using an interdigitated electrode integrated inside the PCR chip. The electrode makes a direct contact with the PCR sample and does not require any labeling or immobilization pretreatment. The input AC voltage for EIS showed the lowest noise at 100 mV. Electrical impedances in a frequency domain were measured during 30 cycles in the PCR of Escherichia coli genomic DNA region (of length 180 bp, 10 ng/μl). From the analysis of EIS data, the magnitude of imaginary value steadily increased with an increase in the PCR cycles and showed the greatest change rate at 186 Hz. For comparing the quantitative performance with previous researches, the figure of merit (FM) was defined as the ratio of normalized sensitivity (NS) to the normalized root mean square error (NRMSE). The performance of the proposed EIS method is similar to that reported in other studies, and the damage of the sample monitored through electrophoresis by EIS measurement was confirmed to be negligible.

     

A novel quantitative measure of breast curvature based on catenary

Quantitative, objective measurements of breast curvature computed from clinical photographs could be used to investigate factors that impact reconstruction and facilitate surgical planning. This paper introduces a novel quantitative measure of breast curvature based on catenary. A catenary curve is used to approximate the overall curvature of the breast contour, and the curvature measure is extracted from the catenary curve. The catenary curve was verified by comparing its length, the area enclosed by the curve, and the curvature measure from the catenary curve to those from manual tracings of the breast contour. The evaluation of the proposed analysis employed untreated and postoperative clinical photographs of women who were undergoing tissue expander/implant (TE/Implant) reconstruction. Logistic regression models were developed to distinguish between the curvature of breasts undergoing TE/Implant reconstruction and that of untreated breasts based on the curvature measure and patient variables (age and body mass index). The relationships between the curvature measures of untreated breasts and patient variables were also investigated. The catenary curve approximates breast curvature reliably. The curvature measure contains useful information for quantifying the curvature differences between breasts undergoing TE/Implant reconstruction and untreated breasts, and identifying the effect of patient variables on the breast shape.     

An analysis method to detect the presence of DNA using electrochemical impedance spectroscopy (EIS) for real-time PCR

Microsystem Technologies - This paper reports a technique for detecting the presence of DNA in real-time PCR using label-free electrochemical impedance spectroscopy. The change in the real and...     

Evaluation of bubble suspension behavior in electrolyte melts

The viscosity of a molten electrolyte mixture commonly used in direct coal fuel cells (DCFCs) was evaluated. The measurements were obtained from near the melting temperature to a high temperature at which a considerably bubbly flow was induced by decomposition. A gravity-driven capillary viscometer was employed to obtain the viscosity data under low Reynolds flow conditions, using a modified Poiseuille flow relationship. The importance of carbon dioxide addition in measuring the intrinsic viscosity was clearly observed. In addition, the effect of the bubble suspension on the viscosity was quantified in terms of the volume fraction and capillary number. The results showed that the increase in viscosity was best explained only by the difference in the volume fraction of spherical bubbles in the electrolyte melt.     

Examination of the oxidation behavior of biodiesel soot

In this work, we expand upon past work relating the nanostructure and oxidative reactivity of soot. This work shows that the initial structure alone does not dictate the reactivity of diesel soot and rather the initial oxygen groups have a strong influence on the oxidation rate. A comparison of the complete oxidation behavior and burning mode was made to address the mechanism by which biodiesel soot enhances oxidation. Diesel soot derived from neat biodiesel (B100) is far more reactive during oxidation than soot from neat Fischer-Tropsch diesel fuel (FT100). B100 soot undergoes a unique oxidation process leading to capsule-type oxidation and eventual formation of graphene ribbon structures. The results presented here demonstrate the importance of initial properties of the soot, which lead to differences in burning mode. Incorporation of greater surface oxygen functionality in the B100 soot provides the means for more rapid oxidation and drastic structural transformation during the oxidation process.