High-Performance Macroporous Free-Standing Microbial Fuel Cell Anode Derived from Grape for Efficient Power Generation and Brewery Wastewater Treatment.

Microbial fuel cells (MFCs) have the potential to directly convert the chemical energy in organic matter into electrical energy, making them a promising technology for achieving sustainable energy production alongside wastewater treatment. However, the low extracellular electron transfer (EET) rates and limited bacteria loading capacity of MFCs anode materials present challenges in achieving high power output. In this study, three-dimensionally heteroatom-doped carbonized grape (CG) monoliths with a macroporous structure were successfully fabricated using a facile and low-cost route and employed as independent anodes in MFCs for treating brewery wastewater. The CG obtained at 900 °C (CG-900) exhibited excellent biocompatibility. When integrated into MFCs, these units initiated electricity generation a mere 1.8 days after inoculation and swiftly reached a peak output voltage of 658 mV, demonstrating an exceptional areal power density of 3.71 W m-2. The porous structure of the CG-900 anode facilitated efficient ion transport and microbial community succession, ensuring sustained operational excellence. Remarkably, even when nutrition was interrupted for 30 days, the voltage swiftly returned to its original level. Moreover, the CG-900 anode exhibited a superior capacity for accommodating electricigens, boasting a notably higher abundance of Geobacter spp. (87.1%) compared to carbon cloth (CC, 63.0%). Most notably, when treating brewery wastewater, the CG-900 anode achieved a maximum power density of 3.52 W m-2, accompanied by remarkable treatment efficiency, with a COD removal rate of 85.5%. This study provides a facile and low-cost synthesis technique for fabricating high-performance MFC anodes for use in microbial energy harvesting.

[Laboratory study of surface electromyography and electrocardiogram in assessing dynamic workload].

OBJECTIVE: To investigate the use of surface electromyography (sEMG) and electrocardiogram (ECG) in evaluation of dynamic workload. METHODS: Through controlling the speed and gradient, 8 subjects ran on the treadmill power machine to simulate the dynamic work. The sEMG signal of anterior tibial muscle (AT) and gastrocnemius muscle (GC) of right lower limb and ECG signal were recorded. The root mean square value (RMS), median frequency (MF), mean power frequency (MPF), heart rate (HR), standard deviation of all normal to normal intervals (SDNN) and Borg scores were analyzed. RESULTS: In the five sports, with the speed increasing, all the values of RMS increased in the AT and GC (P < 0.01). With the gradient increasing, the values of RMS increased in the GC (P < 0.01) while the values of RMS of AT had a trend of decrease (P > 0.05). In all five sports, both the values of MF and MPF in AT and GC were lowest in B sports. Compared to A sport, most of the values of MF and MPF increased in C, D, E sports (P < 0.01), with a highest value in the D sport. Compared with A sport, the HR of B, C, D, E sports significantly increased (P < 0.01), and the highest heart rate was found in B sport, however, the values of SDNN significantly decreased. With the increased speed and gradient, the scores of Borg scale significantly increased. CONCLUSION: In the evaluation of dynamic workload, RMS and HR appear to be good indexes. However, in terms of stress reaction to dynamic workload, MF and MPF are more sensitive.