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

Three-Phase Saturated-Core Fault Current Limiter

The saturated-core fault current limiter (SFCL) is widely used to limit the fault current. However, in the conventional SFCL structure, alternating current (AC) and direct current (DC) coils are wound on different loosely coupled cores. Owing to the leakage inductance, the traditional structure demonstrates relatively large demand for DC excitation power and excessive impedance during saturation. In this study, a new structure for winding closely coupled DC and AC coils on the same core in three phases is proposed to reduce the influence of leakage reactance on the SFCL performance. The leakage magnetic flux generated by both structures is analyzed by performing finite element analysis simulations and utilizing a magnetic field division method. The impedance of the limiter is measured at different DC currents and air gaps to optimize its dynamic performance. A fabricated prototype of the proposed limiter exhibits smaller steady-state losses and high current-limiting capability

The business model of 5G base station energy storage participating in demand response

To achieve the goal of “carbon peak, carbon neutralization”, the proportion of renewable energy access will continue to increase, which will bring a severe test to the balance adjustment ability of the new power system, and the demand for flexible adjustment and real-time balance of the power system will continue to increase. However, pumped storage power stations and grid-side energy storage facilities, which are flexible peak-shaving resources, have relatively high investment and operation costs. 5G base station energy storage to participate in demand response can share the cost of energy storage system construction by power companies and communication operators to achieve a win-win situation between the communication system and the power system. Based on the analysis of the feasibility and incremental cost of 5G communication base station energy storage participating in demand response projects, combined with the interest interaction mechanism of all parties in the project, this paper proposes a business model for 5G energy storage to participate in the grid collaboration and interaction to improve the profit model of various market players, thereby promoting the penetration rate of the project