Novel Core Structure and Iron‐Loss Modeling for Contactless Power Transfer System of Electric Vehicle

A contactless power transfer system for electric vehicles must have high efficiency, a large air gap, good tolerance to misalignment in the lateral direction, compactness, and light weight. In this paper, a new 1.5‐kW transformer has been developed using a novel H‐shaped core which is more efficient, more robust to misalignment, and lighter than previous rectangular cores, to satisfy these criteria, and its characteristics are described. An efficiency of 95% was achieved across a 70‐mm mechanical gap. Iron‐loss modeling of the equivalent circuit is also presented. The calculated efficiency using this model shows good agreement with experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(2): 61–70, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22377     

Stable organic thin-film transistors using full solution-processing and low-temperature sintering silver nanoparticle inks

We have fabricated electronically stable organic thin-film transistor (TFT) devices that are fully solution-processed and adopt printed electrodes using silver nanoparticles dispersed in organic solvents, whose sintering temperatures are 100 °C or less. The bottom-contact organic TFT devices showed good electrical characteristics, and exhibited threshold voltage shifts less than 2.0 V after applying a DC bias voltage stress for 10⁴ s, which is attributed to relatively low contact resistance. These results demonstrate the feasibility of producing stable organic TFTs that are fully solution-processed at relatively low temperatures, for use in large-area flexible electronics applications.     

Dual-Hop Non-regenerative OFDM Relay Systems with Chunk-Based Power Allocation

In this paper, we propose dual-hop non-regenerative Orthogonal Frequency Division Multiplexing (OFDM) relay systems without signal buffering and processing delay due to Fast Fourier Transform (FFT) and Inverse FFT (IFFT) at the Relay Node (RN). One scheme uses per subcarrier Power Allocation (PA) at Source Node (SN) and per chunk PA at RN to improve the achievable rate. Another scheme employs per chunk PA at both SN and RN. Numerical results in mobile communication environments show that both schemes improve the achievable rates compared to conventional simple amplify-and-forward relay systems with per subcarrier PA at RN. In particular, the latter scheme can obtain almost the same or slightly higher achievable rates by selecting an appropriate chunk size in severe frequency selective channel and by setting any chunk size in highly frequency-correlated channels. Therefore, chunk-based PA at both SN and RN can be found a beneficial PA for dual-hop OFDM relay systems in terms of competitive achievable rates and relatively small amount of required channel information to calculate allocated power.     

Fates of foodborne pathogens in raw hams manufactured rapidly using a new patented method

To manufacture raw ham in an efficient manner, we recently developed a new system in which presliced pork loin was used, and the processing time was reduced to 5% of the conventional method. This study aimed to examine whether this raw ham could be as safe as ham produced by the conventional method. Pork loin spiked with enterohemorrhagic Escherichia coli serotype O157:H7, Listeria monocytogenes serotype 1/2c, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus were processed using either the new or conventional method. The fate of the foodborne pathogens and behavior of hygiene indicator bacteria were examined. Whereas nitrite had disappeared during the conventional packaging process, the reduced processing time in the new system allowed for the ham to be vacuum packed with retention of the nitrite (6.9±1.2 ppm, P<0.01). This accounts for the prominent decrease in L. monocytogenes (2.3 log reduction in 35 days) and S. aureus (3.3 log reduction in 13 days) counts during storage. E. coli O157 and Salmonella Enteritidis were likely resistant to the nitrite in the ham. However, they were unable to multiply in the ham and decreased gradually as in the conventionally produced ham. The bacteriostatic nature of the raw ham was also indicated by the gradual decrease in coliforms (1.3 log reduction in 13 days) in nonspiked ham. In conclusion, the raw ham produced using presliced pork loin is practically as safe as conventionally produced raw ham. It is worth validating these results in a small-scale production setting.     

The Role of Leaky Gut in Nonalcoholic Fatty Liver Disease: A Novel Therapeutic Target

The liver directly accepts blood from the gut and is, therefore, exposed to intestinal bacteria. Recent studies have demonstrated a relationship between gut bacteria and nonalcoholic fatty liver disease (NAFLD). Approximately 10–20% of NAFLD patients develop nonalcoholic steatohepatitis (NASH), and endotoxins produced by Gram-negative bacilli may be involved in NAFLD pathogenesis. NAFLD hyperendotoxicemia has intestinal and hepatic factors. The intestinal factors include impaired intestinal barrier function (leaky gut syndrome) and dysbiosis due to increased abundance of ethanol-producing bacteria, which can change endogenous alcohol concentrations. The hepatic factors include hyperleptinemia, which is associated with an excessive response to endotoxins, leading to intrahepatic inflammation and fibrosis. Clinically, the relationship between gut bacteria and NAFLD has been targeted in some randomized controlled trials of probiotics and other agents, but the results have been inconsistent. A recent randomized, placebo-controlled study explored the utility of lubiprostone, a treatment for constipation, in restoring intestinal barrier function and improving the outcomes of NAFLD patients, marking a new phase in the development of novel therapies targeting the intestinal barrier. This review summarizes recent data from studies in animal models and randomized clinical trials on the role of the gut–liver axis in NAFLD pathogenesis and progression.     

Wetting and reaction between Si droplet and SiO<Subscript>2</Subscript> substrate

The wetting and reaction between Si melt and SiO₂ substrate were investigated as a function of the atmosphere, temperature, and degree of vacuum. The results revealed that below 2 Torr with an Ar flow, the wetting angle is finally 90°. The Si droplet was stationary at a wetting angle of 90°. Videos indicated that the droplets moved and vibrated; Above 20 Torr, the Si droplet vibrated up and down with a frequency of approximately 2 Hz, thereby changing the wetting angle. Further, the droplet remained stationary on a substrate on which grooves with a width of 100 μm and depth of 100 μm were etched with a pitch of 1 mm. The presence of grooves or dimples on the substrates facilitated the leakage of SiO gas; as a result, the Si droplet did not vibrate. A vibration model was proposed in which the SiO gas produced at the interface between the Si droplet and the substrate according to the reaction Si + SiO = 2SiO expands and leaks continuously.     

SiC SBDs selection method based on loss analysis of boost converter

Silicon carbide schottky barrier diodes (SiC SBDs) have much better characteristic than Si PiN diode in high voltage applications because SiC SBDs do not have recovery effect. However, simple replacing is not the most effective way. In a boost converter, the power loss caused by the SiC SBD can be divided into the conduction loss of the SiC SBD and the loss caused by the energy stored in the junction capacitance of the SiC SBD. Therefore analysis of not only the conduction loss but also the loss caused by the energy stored in the junction capacitance of the SiC SBD can realize the SiC SBD selection to improve the efficiency of the boost converter. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

3D-Printed Methane-Producing Electrodes for Microbial Fuel Cells Developed Using Biogel Ink Containing Live Methanogens and White Charcoal

Methanogens are used as catalysts for cathodes in microbial fuel cells, to reduce CO₂ to CH₄. However, the attachment of microbes to the electrodes via culturing is time-consuming, and inadequate biofilm formation can lead to lesser surface area coverage, resulting in reduced methane formation. This study aims to improve the production efficiency and performance of methanogen cathodes developed using 3D printing of bioink containing live methanogens. A progressive cavity pump is used for the 3D gel-printing of methanogens and micro-sized white charcoal particles into the desired structure. Despite the absence of anaerobic conditions during printing, the 3D-printed cathodes with higher concentrations of microbial inoculum in the bioink produce more methane gas. Even with an unconcentrated inoculum, the methanogens multiply 800-fold during incubation, resulting in increased methane gas production. The predominant methanogens in the electrodes included the hydrogenotrophic Methanobacterium spp. Therefore, the technique used in this study can be used to successfully develop 3D-printed biocathodes catalyzed by methanogenic microbes with verifiable practical applicability. This study is the first to report the growth of methanogens and their methanogenic activity in 3D-printed cathodes.     

Fluorophore-Decorated Mie Resonant Silicon Nanosphere for Scattering/Fluorescence Dual-Mode Imaging

Inorganic nanoparticles with multiple functions have been attracting attention as multimodal nanoprobes in bioimaging, biomolecule detection, and medical diagnosis and treatment. A drawback of conventional metallic nanoparticle-based nanoprobes is the Ohmic losses that lead to fluorescence quenching of attached molecules and local heating under light irradiation. Here, metal-free nanoprobes capable of scattering/fluorescence dual-mode imaging are developed. The nanoprobes are composed of a silicon nanosphere core having efficient Mie scattering in the visible to near infrared range and a fluorophore doped silica shell. The dark-field scattering and photoluminescence images/spectra for nanoprobes made from different size silicon nanospheres and different kinds of fluorophores are studied by single particle spectroscopy. The fluorescence spectra are strongly modified by the Mie modes of a silicon nanosphere core. By comparing scattering and fluorescence spectra and calculated Purcell factors, the fluorescence enhancement factor is quantitatively discussed. In vitro scattering/fluorescence imaging studies on human cancer cells demonstrate that the developed nanoparticles work as scattering/fluorescence dual-mode imaging nanoprobes.     

Strategic cost and sustainability analyses of injection molding and material extrusion additive manufacturing

Economic and environmental costs are assessed for four different plastics manufacturing processes, including cold and hot runner molding as well as stock and upgraded material extrusion three dimensional (3D) printers. A larger stock 3D printer was found to provide a melting capacity of 14.4 ml/h, while a smaller printer with an upgraded extruder had a melting capacity of 36 ml/h. 3D printing at these maximum melting capacities resulted in specific energy consumption (SEC) of 16.5 and 5.28 kWh/kg, respectively, with the latter value being less than 50% of the lowest values reported in the literature. Even so, analysis of these respective processes found them to be only 2.9% and 3.8% efficient relative to their theoretical minimum energy requirements. By comparison, cold and hot runner molding with an all-electric machine had SEC of 1.28 and 0.929 kWh/kg, respectively, with efficiencies of 9.9% and 13.6% relative to the theoretical minima. Breakeven analysis considering the cost and carbon footprint of mold tooling found injection molding was preferable at a production quantity of around 70,000 units. Parametric analysis of model inputs indicates that the breakeven quantities are robust with respect to carbon tax incentives but highly dependent on mold costs, labor costs, and part size. Dimensional and mechanical properties of the molded and 3D printed specimens are also characterized and discussed.