Embodied greenhouse gas emissions from building China’s large-scale power transmission infrastructure

China has built the world’s largest power transmission infrastructure by consuming massive volumes of greenhouse gas- (GHG-) intensive products such as steel. A quantitative analysis of the carbon implications of expanding the transmission infrastructure would shed light on the trade-offs among three connected dimensions of sustainable development, namely, climate change mitigation, energy access and infrastructure development. By collecting a high-resolution inventory, we developed an assessment framework of, and analysed, the GHG emissions caused by China’s power transmission infrastructure construction during 1990–2017. We show that cumulative embodied GHG emissions have dramatically increased by more than 7.3 times those in 1990, reaching 0.89 GtCO -equivalent in 2017. Over the same period, the gaps between the well-developed eastern and less-developed western regions in China have gradually narrowed. Voltage class, transmission-line length and terrain were important factors that influenced embodied GHG emissions. We discuss measures for the mitigation of GHG emissions from power transmission development that can inform global low-carbon infrastructure transitions.

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

Comparative Investigation of Axial Bearing Performance and Mechanism of Continuous Flight Auger Pile in Weathered Granitic Soils

Axial bearing performance and mechanism of continuous flight auger (CFA) pile in weathered granitic soils, i.e., a widespread special soil in South China, were investigated by field test in this study. Load–settlement responses of four CFA piles were examined, and evolutions of shaft/base resistances were captured by ultra-weak fiber Bragg gratings (UWFBG) with a reflectivity ≤−40 dB. Performances of CFA piles were compared with those of a slurry displacement (SD) pile at the same site, thirteen pretensioned spun high-strength concrete (PHC) piles in the literature and empirical data in design code. Test results show that the ultimate bearing capacity of the CFA pile is highest among different pile types, and typically is twice that of the SD pile. Again, CFA pile produces the highest shaft resistances at 140 kPa and 153 kPa in two weathered granitic soils, while the base resistance of 3080 kPa is between those of the SD pile and the PHC pile. By field excavation, the superior mechanism of the CFA pile is suggested to avoid the formation of in-between bentonite layers and prevent preferential baseflow along fissures, both of which can weaken the soil–pile interface. Overall, this study provides fundamental data through UWFBG and explanations based on field observations which underpin the need for developing a design code specified for CFA piles in South China

Operando monitoring of dendrite formation in lithium metal batteries via ultrasensitive tilted fiber Bragg grating sensors

Abstract Lithium (Li) dendrite growth significantly deteriorates the performance and shortens the operation life of lithium metal batteries. Capturing the intricate dynamics of surface localized and rapid mass transport at the electrolyte–electrode interface of lithium metal is essential for the understanding of the dendrite growth process, and the evaluation of the solutions mitigating the dendrite growth issue. Here we demonstrate an approach based on an ultrasensitive tilted fiber Bragg grating (TFBG) sensor which is inserted close to the electrode surface in a working lithium metal battery, without disturbing its operation. Thanks to the superfine optical resonances of the TFBG, in situ and rapid monitoring of mass transport kinetics and lithium dendrite growth at the nanoscale interface of lithium anodes have been achieved. Reliable correlations between the performance of different natural/artificial solid electrolyte interphases (SEIs) and the time-resolved optical responses have been observed and quantified, enabling us to link the nanoscale ion and SEI behavior with the macroscopic battery performance. This new operando tool will provide additional capabilities for parametrization of the batteries’ electrochemistry and help identify the optimal interphases of lithium metal batteries to enhance battery performance and its safety

Evaluation of the ability of STD laboratories to detect Chlamydia trachomatis in Guangdong province

Objective To evaluate the ability of sexually transmitted disease (STD) laboratories in different medical institutions to detect Chlamydia trachomatis in Guangdong province. Methods The samples of Chlamydia trachomatis were prepared and distributed to all participants, without specified detection methods. The test results, methods and reagents were reported through the EQA online reporting system of provincial STD laboratory. If the results agreed with the expected results, a score of 2 would be achieved. Otherwise, the score was zero. The test results from different medical institutions, the types of STD laboratories and testing methods were compared. Results A total of 694 laboratories, including 388 secondary and higher-level medical institutions, 82 maternal and child health institutions, 79 chronic disease prevention institutions, and 145 primary or other medical institutions, participated in the evaluation of the inter-laboratory ability. Of the 694 laboratories, 537 were standardized STD laboratories and 157 were general laboratories. The overall conformity rate was 96.11%, with a qualification rate of 98.70%. Notably, the conformity rate of laboratories in chronic disease prevention institutions was the highest (98.23%). The standardized STD laboratories achieved significantly higher scores (Z=4.25) and qualification rates (χ2=22.87) than non-standardized laboratories (both P<0.001). Additionally, the nucleic acid testing method yielded a significantly higher score than the immunochromatographic method (Z=3.72, P<0.001). Conclusions The ability to detect Chlamydia trachomatis is high in the STD laboratories in Guangdong province. As the institutions dedicated to the prevention and treatment of STDs, skin venereal disease prevention and control institutions show a higher conformity rate. Moreover, standardized STD laboratories demonstrate higher detection ability than the non-standardized STD laboratories. Therefore, strengthening the standardization of STD laboratories can effectively improve the detection ability. Meanwhile, the nucleic acid testing method is recommended for Chlamydia trachomatis in clinical practice