A Three-Phase Interleaved Floating Output Boost Converter

High step-up dc-dc converter is an essential part in several renewable energy systems. In this paper, a new topology of step-up dc-dc converter based on interleaved structure is proposed. The proposed converter uses three energy storing capacitors to achieve a high voltage gain. Besides the high voltage gain feature, the proposed converter also reduces the voltage stress across the semiconductor switches. This helps in using low rating switching devices which can reduce the overall size and cost of the converter. The operating principle of the proposed converter is discussed in detail and its principle waveforms are analyzed. An experiment is carried out on a 20 V input, 130 V output, and 21 W power prototype of the proposed converter in the laboratory to verify the performance of the proposed converter. An efficiency of 91.3% is achieved at the rated load

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Functionalized Bimetallic Hydroxides Derived from Metal–Organic Frameworks for High-Performance Hybrid Supercapacitor with Exceptional Cycling Stability

A hybrid supercapacitor consisting of a battery-type electrode and a capacitive electrode could exhibit dramatically enhanced energy density compared with a conventional electrical double-layer capacitor (EDLCs). However, advantages for EDLCs such as stable cycling performance will also be impaired with the introduction of transition metal-based species. Here, we introduce a facile hydrothermal procedure to prepare highly porous MOF-74-derived double hydroxide (denoted as MDH). The obtained 65%Ni-35%Co MDH (denoted as 65Ni-MDH) exhibited a high specific surface area of up to 299 m² g^–1. When tested in a three-electrode configuration, the 65Ni-MDH (875 C g^–1 at 1 A g^–1) exhibited excellent cycling stability (90.1% capacity retention after 5000 cycles at 20 A g^–1). After being fabricated as a hybrid supercapacitor with N-doped carbon as the negative electrode, the device could exhibit not only 81 W h kg^–1 at a power density of 1.9 kW kg^–1 and 42 W h kg^–1 even at elevated working power of 11.5 kW kg^–1, but also encouraging cycling stability with 95.5% capacitance retention after 5000 cycles and 91.3% after 10 000 cycles at 13.5 A g^–1. This enhanced cycling stability for MDH should be associated with the synergistic effect of hierarchical porous nature as well as the existence of interlayer functional groups in MDH (proved by Fourier transform infrared spectroscopy (FTIR) and in situ Raman spectroscopy). This work also provides a new MOF-as-sacrificial template strategy to synthesize transition metal-based hydroxides for practical energy storage applications