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This study investigates a novel isometric method utilizing an external focus instruction technique with a soft paper balloon. By emphasizing control to avoid crushing the balloon, this method promotes co-contraction of muscles without exerting pressure on the object. We aim to evaluate differences in muscle activation patterns during isometric hip abduction exercises between the paper balloon task and tasks using external resistance (hard plastic, non-elastic, and elastic bands), and further determine their influence on the contralateral side. Thirteen healthy adult males aged 20–28 years were recruited. Six trunk muscles (transversus abdominis [TrA], internal oblique [IO], external oblique, rectus abdominis, multifidus [MF], and lumbar erector spinae) and five lower-extremity muscles (gluteus maximus [GMax], gluteus medius [GMed], adductor longus, rectus femoris [RF], and biceps femoris [BF]) were measured using surface and fine-wire electrodes to compare the different isometric hip abduction exercises. The muscle activity did not differ between the abduction sides except for GMax and GMed with the elastic band and RF and BF with the hard plastic (p > 0.05). The trunk muscles (TrA, IO, and MF) were similarly activated with the paper balloon and external loading tasks; however, the paper balloon task activated trunk muscles without bearing weight, potentially avoiding pressure on the spine, knee, or hip joints. Moreover, all tasks showed muscle activation on the opposite side of the body. [ABSTRACT FROM AUTHOR]

The crisis of obtaining drinking water and electrical energy from clean sources has been the primary focus of researchers seeking ecologically acceptable and cost‐effective alternatives. The microbial desalination cell (MDC) has shown to be one of the most cost‐effective and promising ways for creating electricity, cleaning sewage water, and naturally desalinating water. In this work, the AEM (Anion Exchange Membrane) was used in the anodic chamber, and potassium ferricyanide in the cathodic chamber as catholyte solution. Meanwhile, SEM (Scanning electron microscopy) analyses was used to define the resulting surface morphologies. This study gave an optimization model by Central Composite Design model, where all the variables affecting the microbial desalination cell (the initial concentration of COD (Chemical Oxygen Demand), the initial concentration of TDS (Total dissolved solids) and the operating time of the cell) were entered to obtain an equation for each response (electrical energy productivity, COD removal efficiency and water desalination efficiency) in addition to study the ANOVA (Analysis of variance) for each response and study the interactions of the variables with each other that affect the response. The variables were determined for the initial concentration of (COD) from (300‐1200 mg/L) and the initial concentration of (TDS) from (15–35 g/L) and the duration of the operating time was from (4–24 h) the maximum productivity was obtained. The power was 2.2 mW, and the maximum water desalination gave 42 %, and the optimum COD removal was 35 %. In addition to diagnosing the active sludge employed and defining the kind of bacteria controlling it, this research looked at the breakdown of the yield of ion exchange membranes, which had a negative impact on the desalination process and the productivity of electrical energy. [ABSTRACT FROM AUTHOR]

The Russian war against Ukraine in February 2022, unleashed an unprecedented wave of non-governmental, external resistance directed against Russia. In many ways, previous literature on war and resistance does not capture the characteristics of this phenomenon. Besides noting the presence of civilian war protests outside of the warzone, most research has focused on internal resistance during war. In this article, we draw on a wider array of resistance literature and present an analytical framework that allows us to capture the broad elements of non-governmental, external resistance during war – including the power-resistance nexus at work. The analytical framework sorts the various kinds of resisters, it categorises the form of resistance and the targets pursued. The usefulness of the analytical framework is demonstrated through an exploration of empirical examples and illustrations drawn from media reports gathered during the first 10 days of the war in Ukraine. It is concluded that new analytical tools are necessary in order to capture non-governmental, external resistance during war as it is waged in Europe in the 2020s. [ABSTRACT FROM AUTHOR]

Dual-chamber microbial fuel cells (DC-MFC) are devices that can be used to generate electricity through the degradation of substrates. In this study, the performance of DC-MFC with novel electrode materials is evaluated under different external resistance using a hydrochloric acid solution as catholyte. Hydrophilic-treated graphene was used as the electrode material, DuPontTM Nafion 117 was used as the proton exchange membrane and domestic wastewater served as the substrate. The maximum power density achieved was 32.05 mW⋅m−2, obtained by degrading 69.8% of organic matter when an external resistance of 100 Ω was used as electrical load. This power density was 32 times higher than the power density obtained in the control (1.01 mW⋅m−2). This result obtained was similar to those reported in the literature for small-scale DC-MFC systems. And, contrary to the reported trend that as the scale of MFCs increase, the efficiency decreases. It can be stipulated with these results that is possible to scale up DC-MFC to medium-scale systems without loss performance quality by selecting the appropriate external resistance, catholyte and electrode materials.

BACKGROUND: Microbial desalination cell (MDC) is a new technology in the use of electrical energy for water desalination and wastewater treatment. RESULTS: Open circuit (OC) and closed circuit (CC) modes were successfully simulated with initial TDS concentrations of 10 g/L and 10–15 g/L, respectively (an external resistance of only 150 Ω was applied for CC). After 160 h of operation, the maximum OC voltage, desalination efficiency and COD removal efficiency were 809 mV, 32.2% and 79.2%, respectively. The maximum voltage was also obtained when the external resistances were 150 Ω (423.4 and 438 mV) for the initial NaCl concentrations (10 and 15 g/L) in the central chamber, respectively. Moreover, the maximal desalting and COD removal efficiencies after 24 h run‐time were (30% and 28%) and (24% and 25%) for initial NaCl concentrations (10 or 15 g/L) in the central chamber, respectively. Maintaining pH (8.61, 7.01) to (7.85, 7.8) in anode and cathode chambers was studied. This research accurately depicted microbial desalination's efficiency in generating OC voltages and CC electrical energy via Box–Behnken Design Distribution (BBD). Investigated factors' interactions (initial salt/COD concentrations, time) on CC system's energy efficiency. Resulted in peak productivity at (1.85 mW), OC reaching (1100 mV). CONCLUSION: Finally, the research paper gave exciting results in improving the efficiency of the microbial desalination cell to increase the ability to produce electrical energy and desalinate water. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

To address the calculating difficulty of external resistance of vertical tube in the widely used indirect evaporative coolers, this paper experimentally investigates the influencing factors of the tube external resistance and develops calculation formula for tube external resistance. An experimental setup was constructed to test the external resistance of different numbers of tube rows at wind speeds of 1 m/s, 1.5 m/s, 2 m/s, 2.5 m/s, and 3 m/s. A specific vertical tube indirect evaporative cooler with a tube diameter of 25 mm, tube-to-tube center distance of 35 mm, and row-to-row center distance of 30 mm was studied. It was found that the tube external resistance of the studied cases is mainly affected by the face wind speed and the number of tube rows. Based on the response surface method (RSM), a formula for calculating the tube external resistance was fitted using the measured data, which provides guidance for engineering applications of vertical tube type indirect evaporative coolers.

The increase in the population and rapid industrialization generates a significant amount of wastewater which should be treated economically. Microbial desalination cell (MDC) is a kind of technology that can treat wastewater and generate power simultaneously. It was observed that many experimental studies were lacking in findings of the variation of basic input conditions on the MDC efficiencies. The aim of the present study was to explore the impact of external resistance, electrolyte solutions and substrate concentration on power generation in an MDC system. The experimental study was conducted by using medium to high strength wastewater from distillery and brewery industry in batch-wise operation. The analysis of which resulted in medium to high-strength wastewater. The data was collected based on the experimental setup conditions. Application of different resistances on the MDC, best resulted in 82% COD removal and 57% TDS removal with 500 O external resistance. A COD and TDS removal efficiency of 83% and 61% was identified with an electrolyte concentration of 35,000 mg/L. The variation of substrate concentration reported a maximum COD removal of 86%, TDS removal of 62%, and current, and voltage of 1.872 mA and 628 mV with 1,500 and 8,000 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Electroactive biofilms (EABs) have aroused wide concern in waste treatment due to their unique capability of extracellular electron transfer with solid materials. The combined effect of different operating conditions on the formation, microbial architecture, composition, and metabolic activity of EABs is still unknown. In this study, the impact of three different factors (anode electrode, substrate concentration, and resistance) on the acclimation and performance of EABs was investigated. The results showed that the shortest start-up time of 127.3 h and highest power density of 0.84 W m−2 were obtained with carbon brush as electrode, low concentration of substrate (1.0 g L−1), and 1000 Ω external resistance (denoted as N1). The EABs under N1 condition also represented strongest redox capacity, lowest internal resistance, and close arrangement of bacteria. Moreover, the EABs cultured under different conditions both showed similar results, with direct electron transfer (DET) dominated from EABs to anode. Microbial community compositions indicated that EABs under N1 condition have lowest diversity and highest abundance of electroactive bacteria (46.68%). Higher substrate concentration (3.0 g L−1) promoted the proliferation of some other bacteria without electroactivity, which was adverse to EABs. The metabolic analysis showed the difference of genes related to electron transfer (cytochrome C and pili) and biofilm formation (xap) of EABs under different conditions, which further demonstrated the higher electroactivity of EABs under N1. These results provided a comprehensive understanding of the effect of different operating conditions on EABs including biofilm formation and electrochemical activity. [ABSTRACT FROM AUTHOR]

Energy can be harvested from various energy sources within a building. In this study, a thermoelectric generator-assisted energy harvesting block was proposed, aiming to utilize the waste heat source of the exterior wall of the building. The energy harvesting block comprises a thermoelectric generator and phase change material for converting waste heat from the building envelope and heat flux from the outside into electricity. Multiple energy harvesting blocks are required to construct an energy harvesting block wall. Thus, the electrical arrangements of multiple energy harvesting blocks and their effects on external resistance were analyzed. The arrangements consisted of a series array, parallel array, and combination array. Experiments were performed with a total of nine cases by connecting 1.6 Ω, 15 Ω, and 60 Ω with the same external resistance as the internal resistance of each array. The temperature and closed-circuit voltage were measured based on the sol-air temperature profile in December. The voltage and current were more affected by the connected external resistance than by the type of array. The maximum generated energy was 0.837 Wh/day when 60 Ω was connected to the series arrangement. In terms of the generated energy, the series arrangement was the most advantageous. [ABSTRACT FROM AUTHOR]

The enhancement of up-flow constructed wetland-microbial fuel cell (UFCW-MFC) performance in energy retrieval from caffeine containing wastewater has been explored via various operating conditions (hydraulic retention time (HRT), multianode (MA), multicathode current collector (MC), external resistance). The anaerobic decaffeination and COD removal improved by 37 and 12% as the HRT extended from 1 to 5 d. The increment in contact time between the microbes and organic substrates promoted the degradation and contributed to higher power output (3.4-fold), CE (eightfold), and NER (14–16-fold). The MA and MC connections facilitated the electron transfer rate and the degradation rate of organic substrates in the multiple anodic zones, which enhanced the removal efficiency in the anaerobic compartment (Caffeine: 4.2%; COD: 7.4%) and led to higher electricity generation (Power: 4.7-fold) and energy recovery (CE: 1.4-fold; NER: 2.3–2.5-fold) compared to SA. The lower external resistance favored the growth of electrogens and induced higher electron flux, where the best treatment performance and electricity production was obtained when the external resistance approached the internal resistance. Overall, it was noteworthy that the optimum operating conditions were achieved with 5 d HRT, MA, and MC connection along with external resistance of 200 Ω, which significantly outperformed the initial conditions (1 d HRT, SA connection, and 1000 Ω) by 43.7 and 29.8% of caffeine and COD removal in the anaerobic compartment, respectively as well as 14-fold of power generation. [ABSTRACT FROM AUTHOR]

AbstractIn this study the influence of the external circuit resistance on the metabolic behaviour of anodic biofilm in Microbial fuel cell (MFC) was studied. The results obtained demonstrated that extremely low and extremely high circuit loads could deteriorate the bio-electrochemistry of anodic respiration by shifting the microbial metabolism towards typical fermentation of the substrates. The best conditions for respiration and efficient substrate mineralisation of nearly 70% were found in the MFC reactor with 0.1 kΩ resistance in the anode and cathode connecting circuit. Two species of electrochemically active bacteria were isolated from the anodic community and were taxonomically affiliated to Pseudomonas and Bacillus genera based on 16 s rRNA genes amplification and sequencing.

Cathode in photocatalytic fuel cell (PFC) plays a crucial role in degradation of organic contaminants. In this study, synthesized copper oxide (CuO) was loaded on carbon plate and used as photocathode in PFC for degradation of synthetic azo dye Reactive Black 5 (RB5) and real textile wastewater. Morphology and structural phase of the synthesized CuO were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Several operating parameters had been investigated such as light irradiation, initial dye concentration, and pH of azo dye solution within 6 h of irradiation time. The lowest initial concentration of RB5 (10 mg L−1) achieved 100% color removal compared to the highest initial concentration (40 mg L−1) which only achieved 77.1% color removal within 6 h of irradiation time. The influence of external resistance was significant in electricity generation but trivial in dye degradation efficiency. The external resistance of 6000 Ω yielded highest maximum power density, with Pmax of 0.2631 μW cm−2, followed by 1000 Ω (0.2196 μW cm−2) and 8000 Ω (0.1587 μW cm−2), respectively. The real textile wastewater with dilution ratio (DR) 1:6 yielded the highest energy conversion efficiency, η (3.62%), followed by DR 1:4 (3.19%) and DR 1:2 (1.96%), respectively. [ABSTRACT FROM AUTHOR]

In this study, the effects of an external resistance, new electrode material, and non-conventional catholyte on the energy generation and performance of a dual-chamber MFC were evaluated. Ten different resistances (15 Ω–220 kΩ), hydrophilically-treated graphene and graphite electrodes, and a 0.1 M HCl solution as a catholyte were assessed. The results showed that greater energy generation and power density were achieved at an external resistance of 2 kΩ and internal resistance between 2 and 5 kΩ on average; meanwhile, the greatest coulombic efficiency was obtained at the lowest external resistance evaluated (15 Ω). Therefore, it is recommended to operate the MFCs at the external resistance between 2 and 5 kΩ to ensure the maximum power generation of the dual chamber MFCs. Regarding the two electrode materials evaluated as an anode and cathode, hydrophilically-treated graphene was found to be a much better material to enhance the energy production and performance of the MFC system; therefore, its use is suggested in experimental and practical applications. On the other hand, the use of HCl as a catholyte enhanced the performance of MFC (constant and steady potential and greater coulombic efficiency) in most cases. [ABSTRACT FROM AUTHOR]

In this paper, the application of magnetite-nanoparticles and a microbial fuel cell (MFC) was studied on the anaerobic digestion (AD) of sewage sludge. The experimental set-up included six 1 L biochemical methane potential (BMP) tests with different external resistors: (a) 100 Ω, (b) 300 Ω, (c) 500 Ω, (d) 800 Ω, (e) 1000 Ω, and (f) a control with no external resistor. The BMP tests were carried out using digesters with a working volume of 0.8 L fed with 0.5 L substrate, 0.3 L inoculum, and 0.53 g magnetite-nanoparticles. The results suggested that the ultimate biogas generation reached 692.7 mL/g VSfed in the 500 Ω digester, which was substantially greater than the 102.6 mL/g VSfed of the control. The electrochemical efficiency analysis also demonstrated higher coulombic efficiency (81.2%) and maximum power density (30.17 mW/ m2) for the 500 Ω digester. The digester also revealed a higher maximum voltage generation of 0.431 V, which was approximately 12.7 times the 0.034 V of the lowest-performing MFC (100 Ω digester). In terms of contaminants removed, the best-performing digester was the digester with 500 Ω, which reduced contaminants by more than 89% on COD, TS, VS, TSS and color. In terms of cost-benefit analysis, this digester produced the highest annual energy profit (48.22 ZAR/kWh or 3.45 USD/kWh). This infers the application of magnetite-nanoparticles and MFC on the AD of sewage sludge is very promising for biogas production. The digester with an external resistor of 500 Ω showed a high potential for use in bioelectrochemical biogas generation and contaminant removal for sewage sludge. [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimal bioelectro-Fenton (BEF) resistance and NaCl values were obtained by RSM. • Optimized BEF system increased H 2 O 2 generation and removed 99.4% of bisphenol A. • Optimized BEF was stabilized to remove 70% of BPA after five operation cycles. • Optimized BEF enhanced the number of electricity-producing bacteria in the anode. This study is the first to investigate the effects of external resistance and electrolyte concentration on the performance of a bioelectro-Fenton (BEF) system, involving measurements of power density, H 2 O 2 generation, and bisphenol A (BPA) removal efficiency. With optimized operating conditions (external resistance of 1.12 kΩ and cathodic NaCl concentration of 1,657 mg/L), the BEF system achieved a maximum power density of 38.59 mW/m2, which is about 3.5 times higher than with 1 kΩ external resistance and no NaCl. This system featured a 71.7 % reduction in total internal resistance. The optimized BEF also accelerated the oxygen reduction reaction rate, increasing H 2 O 2 generation by 4.4 times compared to the unoptimized system. Moreover, it exhibited superior BPA degradation performance, removing over 99 % of BPA within 14 hs, representing a 1.1 to 3.3-fold improvement over the unoptimized BEF. By the fifth cycle (70 h), the optimized BEF still removed 70 % of BPA. Optimizing the operating conditions significantly increased the abundance of electrochemically active bacteria (Pseudomonadaceae) from 2.2 % to 20 %, facilitating rapid acclimation. The study demonstrates the strong potential of an optimized BEF system for removing persistent pollutants. [ABSTRACT FROM AUTHOR]

This paper presents an extended mathematical model for a microbial desalination cell (MDC), integrating Haldane kinetics for substrate inhibition and proton translocation theory for substrate dissociation under dynamic flow. The model is capable of predicting exoelectrogenic and methanogenic biomass dynamics, acetate removal efficiencies, salt concentration changes, and current production. Notably, it can be used to explore the influence of operational parameters such as dilution rates, temperatures, and external resistances. Our simulations reveal the optimal conditions for maximizing exoelectrogen concentration (500 mg/L) with minimal methanogen presence (50 mg/L) in the anode chamber at an anolyte dilution rate of 0.5 d−1, a temperature of 20 °C, and an influent acetate concentration of 1500 mg/L. The model accurately predicts the salt reduction in the middle chamber (from 0.2 to 0.09 mol/L) with a salt dilution rate of 0.5 d−1 and an external resistance of 20 Ohm. The model predicts a peak power output of 2.5 mW at external resistances between 20 and 50 Ohm. The model was validated against a suite of experimental literature data, including our previously published lab-scale studies, verifying its accuracy in predicting organic and salt removal rates, current production, and desalination efficiency. This extended model is a valuable tool for understanding the complex interactions between factors that influence MDC performance and can guide the optimization of MDC design for wastewater treatment and desalination. [Display omitted] • The extended MDC model can stimulate oxidizied mediator and substrate inhibition concentrations. • Exoelectrogens and methanogens concentrations are predicted at different anolyte dilution rates. • Hydrolysis of soluble organic substrate indicates the pH effect on MDC performance. • Acetate and salt removal can be efficiently detected using an extended model. • Cell power and Coulombic efficiency can be optimized at MDC external resistance. [ABSTRACT FROM AUTHOR]

The green and cost-effective nature of the microbial desalination cell (MDC) make it a promising alternative for future sustainable desalination. However, MDC suffers from a low desalination rate that inhibits it being commercialized. External resistance (Rext) is one of the factors that significantly affect the desalination rate in MDCs, which is still under debate. This research, for the first time, investigated the impact of Rext on MDCs with different internal resistance (Rint) of the system to discover the optimal range of Rext for efficient MDC performance. The results showed that the effect of Rext on desalination rate (2.52 mg/h) was quite low when the Rint of MDC was high (200 Ω). However, operating the MDC with a low Rint (67 Ω) significantly improved the desalination rate (9.85 mg/h) and current generation. When MDC was operated with a low Rint the effect of variable Rext on desalination and current generation was noticeable. Therefore, low Rint (67 Ω) MDC was used to select the optimum Rext when the optimal range was found to be Rext ≪ Rint, Rext < Rint, Rext ≈ Rint (ranging from 1–69 Ω) to achieve the highest desalination rates (10.41–8.59 mg/h). The results showed the superior effect of Rint on desalination rate before selecting the optimal range of Rext in the outer circuit. HIGHLIGHTS Low desalination rate in MDCs involves both Rext and Rint.; Impact of Rext and Rint was collectively investigated in MDCs.; Effect of Rext was insignificant when internal resistance was high.; Optimum range of Rext was explored for MDC with low Rint.; Rext ≪ Rint, Rext < Rint, Rext ≈ Rint were the optimum Rext for high desalination rate.;

External resistance is important for the anode and cell performance. However, little attentions were paid on the effect of external resistance on the variation of biofilm structure. Here, we used external resistance ranged from 4000 to 500 Ω for anodic acclimation to investigate the correlation between anode performance and biofilm structure. With the reduce of external resistance, the maximum current density of anode increased from 1.0 to 3.4 A/m2, which was resulted from a comprehensive effect of reduced charge transfer resistance and increased diffusion resistance. Biological analysis showed that with the reduce of external resistance, biomass and extracellular polymeric substances content increased by 109 and 286%, cell viability increased by 22.7%, which contributed to the reduced charge transfer resistance. But the porosity of anodic biofilm decreased by 27.8%, which led to an increased diffusion resistance of H+. This work provided a clear correlation between the electrochemical performance and biofilm structure. [ABSTRACT FROM AUTHOR]

In this study the influence of the external circuit resistance on the metabolic behaviour of anodic biofilm in Microbial fuel cell (MFC) was studied. The results obtained demonstrated that extremely low and extremely high circuit loads could deteriorate the bio-electrochemistry of anodic respiration by shifting the microbial metabolism towards typical fermentation of the substrates. The best conditions for respiration and efficient substrate mineralisation of nearly 70% were found in the MFC reactor with 0.1 kΩ resistance in the anode and cathode connecting circuit. Two species of electrochemically active bacteria were isolated from the anodic community and were taxonomically affiliated to Pseudomonas and Bacillus genera based on 16 s rRNA genes amplification and sequencing. [ABSTRACT FROM AUTHOR]

In previous studies, a microbial fuel cell (MFC) was developed as a potential sensor that detects iron in water. However, to realize such an application in practice, the electrical signal generation of the MFC must be improved. Therefore, in this study, we investigated several measures to optimize the electrical signals of the MFC including (i) changing the anode spacing, (ii) testing different oxygen supply rates, (iii) testing different external resistances, and (iv) testing a new electrode material. An anode spacing of 2 cm was found to be optimal as the MFC generated a current that was at least 2-fold higher than any other anode spacing investigated. To limit oxygen diffusion from the cathode to the anode, an optimal cathode air flow rate of 1.8 ml min-1 was found, which corresponds to an oxygen supply rate of 0.286 mg min-1. By a polarization experiment, a 60-Ω external resistance ensured the most stable MFC-generated current , which is compulsory for the use of the device as a biosensor. Finally, activated carbon was shown to be an excellent material to improve electrical signal generation by 2-fold in comparison with graphite felt and graphite granules. These reported results will be the basis of further development of the MFC toward a practical biosensor.

In this study, the effects of an external resistance, new electrode material, and non-conventional catholyte on the energy generation and performance of a dual-chamber MFC were evaluated. Ten different resistances (15 Ω–220 kΩ), hydrophilically-treated graphene and graphite electrodes, and a 0.1 M HCl solution as a catholyte were assessed. The results showed that greater energy generation and power density were achieved at an external resistance of 2 kΩ and internal resistance between 2 and 5 kΩ on average; meanwhile, the greatest coulombic efficiency was obtained at the lowest external resistance evaluated (15 Ω). Therefore, it is recommended to operate the MFCs at the external resistance between 2 and 5 kΩ to ensure the maximum power generation of the dual chamber MFCs. Regarding the two electrode materials evaluated as an anode and cathode, hydrophilically-treated graphene was found to be a much better material to enhance the energy production and performance of the MFC system; therefore, its use is suggested in experimental and practical applications. On the other hand, the use of HCl as a catholyte enhanced the performance of MFC (constant and steady potential and greater coulombic efficiency) in most cases.

In this paper, the application of magnetite-nanoparticles and a microbial fuel cell (MFC) was studied on the anaerobic digestion (AD) of sewage sludge. The experimental set-up included six 1 L biochemical methane potential (BMP) tests with different external resistors: (a) 100 Ω, (b) 300 Ω, (c) 500 Ω, (d) 800 Ω, (e) 1000 Ω, and (f) a control with no external resistor. The BMP tests were carried out using digesters with a working volume of 0.8 L fed with 0.5 L substrate, 0.3 L inoculum, and 0.53 g magnetite-nanoparticles. The results suggested that the ultimate biogas generation reached 692.7 mL/g VSfed in the 500 Ω digester, which was substantially greater than the 102.6 mL/g VSfed of the control. The electrochemical efficiency analysis also demonstrated higher coulombic efficiency (81.2%) and maximum power density (30.17 mW/ m2) for the 500 Ω digester. The digester also revealed a higher maximum voltage generation of 0.431 V, which was approximately 12.7 times the 0.034 V of the lowest-performing MFC (100 Ω digester). In terms of contaminants removed, the best-performing digester was the digester with 500 Ω, which reduced contaminants by more than 89% on COD, TS, VS, TSS and color. In terms of cost-benefit analysis, this digester produced the highest annual energy profit (48.22 ZAR/kWh or 3.45 USD/kWh). This infers the application of magnetite-nanoparticles and MFC on the AD of sewage sludge is very promising for biogas production. The digester with an external resistor of 500 Ω showed a high potential for use in bioelectrochemical biogas generation and contaminant removal for sewage sludge.

Dual-chamber microbial fuel cells (DC-MFC) are devices that can be used to generate electricity through the degradation of substrates. In this study, the performance of DC-MFC with novel electrode materials is evaluated under different external resistance using a hydrochloric acid solution as catholyte. Hydrophilic-treated graphene was used as the electrode material, DuPont TM Nafion 117 was used as the proton exchange membrane and domestic wastewater served as the substrate. The maximum power density achieved was 32.05 m W ⋅ m - 2 , obtained by degrading 69.8% of organic matter when an external resistance of 100 Ω was used as electrical load. This power density was 32 times higher than the power density obtained in the control (1.01 m W ⋅ m - 2 ). This result obtained was similar to those reported in the literature for small-scale DC-MFC systems. And, contrary to the reported trend that as the scale of MFCs increase, the efficiency decreases. It can be stipulated with these results that is possible to scale up DC-MFC to medium-scale systems without loss performance quality by selecting the appropriate external resistance, catholyte and electrode materials., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Resistance of sugarcane (Saccharum officinarum L.) to smut disease (caused by Sporisorium scitamineum) is driven by two separate mechanisms, external and internal resistance. Two progenies generated from an introgression cross, with contrasting responses to smut infection were used to investigate this interaction. Histopathological screening at different stages of the plant growth was used to determine the extent of mycelium growth within sugarcane tissues. Ten disease resistance-related genes were selected, and the relative expression determined using quantitative real-time reverse transcription PCR (real-time RT-qPCR). The results revealed that PR10, HCT1 and ScChi were down-regulated in the susceptible progeny and up-regulated in the resistant progeny early infection process. This may reflect an early attempt to halt pathogen development by increasing the lignin deposition at the infection site. At 8 weeks postinoculation, they were highly up-regulated in the susceptible progeny coincided with whip development. This reveals a major role for these genes to whip development in the susceptible progeny and indicates that while PR10 is involved in the resistance mechanism of resistant progeny early infection process it also has a role in susceptibility. These results on genetically related progeny with different responses to smut infection reveal a complex interaction of genes and gene networks being induced in response to fungal invasion. [ABSTRACT FROM AUTHOR]

Air‐cathode microbial fuel cells (AC‐MFC) use a gas‐diffusion‐layer (GDL) coating based on polytetrafluoroethylene applied to the cathode to prevent electrolyte leakage. However, this type of GDL can also lead to a decrease in MFC performance due to electron‐transfer limitation, mass‐transfer limitation or catalyst availability. This study provides a comprehensive understanding of the significance of the GDL coating, demonstrating the interaction between the number of GDL coatings and the external resistance (Rext) used. An experimental design in 28 mL AC‐MFCs was prepared and conducted using two different Rext (10 and 249 Ω) and four different GDL coatings (1 to 4 layers). The coating effect was not significant when operating with a high Rext, where the electron transfer was the limiting process. However, when the Rext was low, the amount of polytetrafluoroethylene limited the cathode performance due to a significant decrease in the Pt availability on the catalytic surface. Thus, GDL‐1 with 10 Ω as Rext reached 0.96 mA/cm2, 3‐fold higher than that obtained with 249 Ω as Rext (ca. 0.30 mA/cm2). Besides, the current density did not vary noticeably in the other cathodes with 249 Ω as Rext. Contrarily, the current density with 10 Ω as Rext decreased as the number of GDL increased (0.74, 0.57 and 0.37 for GDL‐2, GDL‐3 and GDL‐4 respectively). These values agreed with those of the polarization curve. Furthermore, limitations were also observed in electrochemical impedance spectroscopy measurements: the charge resistance increased with the number of GDL, related to the ease of electron flow. These values were18 Ω, 22 Ω, 53 Ω and 58 Ω for GDL‐1, GDL‐2, GDL‐3 and GDL‐4, respectively, for both 10 and 249 Ω cathodes. [ABSTRACT FROM AUTHOR]

• Constructed a highly sensitive MFC sensor for low concentration BOM detection. • The influence mechanism on the sensitivity of MFC sensors was revealed. • The variation of the anode biofilms characteristics was explored. The relatively low sensitivity is an important reason for restricting the microbial fuel cell (MFC) sensors' application in low concentration biodegradable organic matter (BOM) detection. The startup parameters, including substrate concentration, anode area and external resistance, were regulated to enhance the sensitivity of MFC sensors. The results demonstrated that both the substrate concentration and anode area were positively correlated with the sensitivity of MFC sensors, and an external resistance of 210 Ω was found to be optimal in terms of sensitivity of MFC sensors. Optimized MFC sensors had lower detection limit (1 mg/L) and higher sensitivity (Slope value of the linear regression curve was 1.02), which effectively overcome the limitation of low concentration BOM detection. The essential reason is that optimized MFC sensors had higher coulombic efficiency, which was beneficial to improve the sensitivity of MFC sensors. The main impact of the substrate concentration and anode area was to regulate the proportion between electrogens and nonelectrogens, biomass and living cells of the anode biofilm. The external resistance mainly affected the morphology structure and the proportion of living cells of the anode. This study demonstrated an effective way to improve the sensitivity of MFC sensors for low concentration BOM detection. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The effect of electricity, induced by external resistance, on microbial community performance is investigated in Microbial Fuel Cells (MFCs) involved in simultaneous biotransformation of sulfide and nitrate. In the experiment, three MFCs were operated under different external resistances (100 Ω, 1000 Ω and 10,000 Ω), while one MFC was operated with open circuit as control. All MFCs demonstrate good capacity for simultaneous sulfide and nitrate biotransformation regardless of external resistance. MFCs present similar voltage profile; however, the output voltage has positive relationship with external resistance, and the MFC1 with lowest external resistance (100 Ω) generated highest power density. High-throughput sequencing confirms that taxonomic distribution of suspended sludge in anode chamber encompass phylum level to genus level, while the results of principal component analysis (PCA) suggest that microbial communities are varied with external resistance, which external resistance caused the change of electricity generation and substrate removal at the same, and then leads to the change of microbial communities. However, based on Pearson correlation analyses, no strong correlation is evident between community diversity indices (ACE index, Chao index, Shannon index and Simpson index) and the electricity (final voltage and current density). It is inferred that the performance of electricity did not significantly affect the diversity of microbial communities in MFCs biotransforming sulfide and nitrate simultaneously. [ABSTRACT FROM AUTHOR]

The large‐scale wind energy conversion systems (WECSs) based on doubly‐fed induction generators (DFIGs) are very popular in recent years due to the numerous technical and economic benefits. With the increasing penetration level of wind energy, the latest grid codes require the DFIG‐based WECSs to remain connected to the grid under grid fault scenarios and deliver the required reactive power into the grid. However, the direct connection of the stator of the DFIG to the grid makes it prone to grid disturbances, especially to voltage sag. This study proposes a modified demagnetisation control strategy to enhance the low‐voltage ride‐through (LVRT) capability of the DFIG under grid faults. The proposed control strategy is implemented in a coordinated approach by using the existing demagnetisation control and the addition of an external resistance in the stator side of the DFIG. The demagnetisation control damps the direct current component of the stator flux and the external resistance accelerates the damping of the transient flux by decreasing the time constant and hence, enhancing the LVRT capability of DFIG. The effectiveness of the proposed control strategy is demonstrated under both symmetrical and asymmetrical grid faults simulated system through MATLAB/Simulink®. The comparative results justify the merits of the proposed methodology. [ABSTRACT FROM AUTHOR]

In this study, we investigated differences in electromyographic activity in the biceps femoris long head (BFl), semitendinosus, and semimembranosus muscles during 45° hip extension with different knee angles during eccentric, concentric, and isometric hip 0°, and isometric hip 45° conditions with non-external resistance and 5-kg load. Twenty-two male volunteers performed 45° hip extension with knee flexion angles of 0°, 45° and 90° with nonexternal resistance and 5-kg load eccentric, concentric, isometric hip 0°, and isometric hip 45° conditions. The electromyographic data obtained during each condition were normalized with the values collected during maximal voluntary isometric contraction of each muscle. A multivariate analysis of variance with repeated measures using syntax was used to compare the normalized electromyography of each muscle across different knee joint angles in each weight condition. Electromyographic activities of the BFl, semitendinosus, and semimembranosus at 45° and 90° knee flexion angles were significantly greater than at 0° in the eccentric, concentric, isometric hip 0°, and in isometric hip 45° conditions with both non-external resistance and 5-kg load (p<0.05), except for that of the BFl and semitendinosus in isometric hip 45° with 5-kg load. The electromyographic activity of the BFl was significantly higher than that of the semimembranosus at 90° knee flexion in all conditions (p < 0.05), except during eccentric with nonexternal resistance. There was no significant difference in electromyographic activity in the hamstring muscles among different knee angles and muscular contraction conditions. This study showed that 45° hip extension with 45° and 90° knee flexion might be better in terms of the recruiting hamstring activity compared to 0° knee flexion, regardless of the training intensity. We recommend 45° hip extension exercises with knee flexion angles of 45° and 90° to activate the BFl, in preventing hamstring strain. [ABSTRACT FROM AUTHOR]

Water pollution and energy production are major issues in the context of climate change, urbanization and industrialization. There is need for cost-effective and sustainable processes for wastewater treatment. Here we designed a novel system made of a stack of 12 vertically-arranged constructed wetlands coupled with microbial fuel cells. Performance was evaluated in terms of chemical oxygen demand (COD) removal, NH4+–N, NO3−–N, and PO4−3 removal efficiency, and electricity generation. The results reveal that the efficiency of COD removal increased gradually with decreasing external resistance, reaching 98.5% at 0.08 kΩ. The maximum removal efficiency was 90.4% for NH4+–N at 15 kΩ and 86.9% for NO3–N at 0.08 kΩ. The maximum power density reached 30.85 mW/m3 at 15 kΩ. [ABSTRACT FROM AUTHOR]

The effect of external resistance on substrate removal and electricity generation was explored in microbial fuel cells (MFCs) simultaneously treating sulfide and nitrate. The MFCs were operated under three different conditions keeping open-circuit MFC as control. In batch mode, all the MFCs showed good capacity of simultaneously removing sulfide and nitrate regardless of external resistance. The voltage profile could be divided into rapid descent zone, bulge zone, and stability zone, which represents typical polarization behavior. Taking open circuit as control, low external resistance promoted the production of sulfate and nitrogen gas, while a strong link between product production and external resistance was evident based on Pearson correlation analyses. In addition, low external resistance improved the amount of transferred electrons, while the peak electronic quantity was noticed when the external resistance was equivalent to internal resistance. Moreover, the mechanism of substrate removal and electricity generation was hypothesized for the MFCs simultaneously treating sulfide and nitrate which explained the results well. [ABSTRACT FROM AUTHOR]

The performance of microbial desalination cells was investigated concurrently under different substrate strengths and variable external resistances. When the external resistance was fixed at 1,000 Ω, the maximum voltage was 710, 694 and 650 mV at substrate COD concentrations of 500, 1500 and 3000 mg/l respectively. The average COD removal efficiencies were 90.0 ± 5.2, 92.3 ± 4.3 and 53.4 ± 7.2% at substrate concentrations of 500, 1500 and 3000 mg/l respectively. The cell operated at high substrate strength achieved the lowest voltage generation and highest internal resistance. Columbic Efficiencies (CEs) increased with decreased COD loading rates. The cell operated at medium substrate strength achieved the best desalination efficiency due to substrate availability and the lowermost internal resistance. Further investigation was made at different external resistances of 10 to 10,000 Ω which were found to have a significant effect on COD removal and CEs. The high desalination efficiencies were accompanied by higher current densities. Scanning Electron Microscopy (SEM) analyses were conducted for the anode electrode to investigate the biofilm morphology. This study demonstrated interesting results regarding the operation modes that could contribute to the microbial desalination cells scale up. • Substrate strength and its inhibition effect on MDC performance was studied. • Influence of varying external loads on desalination efficiency was investigated. • Recommendation for preferable operation modes was reported. • Biofilm morphology at anodes surface was analyzed at different substrate strengths. [ABSTRACT FROM AUTHOR]

Abstract Microbial fuel cells (MFCs) were incorporated into constructed wetlands (CWs) in recent years aiming to enhance the wastewater treatment of CWs while simultaneously produce electricity. However, currently no information is available about the greenhouse gas (GHG) emissions from integrated CW–MFC systems during wastewater treatment. Therefore, this study investigated the influence of incorporating MFCs on GHG (especially CH 4 and N 2 O) emissions from CWs under different external resistances, influent organic loadings and seasons. Results showed that incorporating the MFC significantly reduced the GHG emissions (by 5.9%–32.4% CO 2 equivalents) from CWs by reducing 17.9%–36.9% CH 4 and 7.2%–38.7% N 2 O emissions. The CH 4 and N 2 O emissions from CW–MFCs significantly increased with increasing external resistance (above 500 Ω), while the CO 2 emission showed the opposite trend. However, the CH 4 and N 2 O emissions at external resistances below 500 Ω did not differ significantly. There was a significant positive correlation between the CO 2 and CH 4 emissions and influent organic loadings in CW–MFCs, but a significant negative correlation between the N 2 O emission and influent organic loadings. Influent chemical oxygen demand/total nitrogen (COD/TN) = 3 could result in a TN removal of ≥90% as well as the minimum CO 2 equivalents emission in CW-MFCs. The GHG emissions from CW–MFCs showed significant seasonal variations. Graphical abstract Integrated constructed wetland–microbial fuel cell (CW–MFC) system: 1. Incorporating the MFC significantly reduced the GHG emissions (by 5.9%–32.4% CO 2 equivalents) from CWs by reducing 17.9%–36.9% CH 4 and 7.2%–38.7% N 2 O emissions. 2. CH 4 and N 2 O emissions from CW–MFCs significantly increased with increasing external resistance (above 500 Ω), while the CO 2 emission showed the opposite trend. 3. CO 2 and CH 4 emissions from CW–MFCs were positively related to organic loadings. 4. N 2 O emission from CW–MFCs was negatively related to organic loadings. 5. Greenhouse gas emissions from CW–MFCs showed significant seasonal variations. Unlabelled Image Highlights • Incorporating the MFC significantly reduced the CH 4 and N 2 O emissions from CWs. • CH 4 and N 2 O emissions from CW–MFCs increased as external resistance increased. • CO 2 and CH 4 emissions from CW–MFCs were positively related to organic loadings. • N 2 O emission from CW–MFCs was negatively related to organic loadings. • Greenhouse gas emissions from CW–MFCs showed significant seasonal variations. [ABSTRACT FROM AUTHOR]

Abstract The relatively poor sensitivity is the main bottleneck restricting the application of microbial fuel cell biosensor (MFC-biosensor) for toxicity monitoring. Previous studies have shown that external resistance (R ext) had an obvious effect on sensor sensitivity. However, these studies reported different results and the reason of this discrepancy was not clear. The objective of this research was to observe the effect of R ext on sensor sensitivity when detecting different types of pollutants and reveal its microbiological mechanism. Results demonstrated that the optimal R ext of MFC-biosensor varied with the type of pollutants. The optimal values for detecting avermectins, tetracyclines and heavy metals were 100 Ω, 330 Ω and 680 Ω, respectively. This discrepancy was mainly due to the visible differences in anodic microbial communities at different R ext settings. Both Azospirillum and Acinetobacter were susceptible to Cd and Pb, occuping 19.20% of the anodic microbial population in 680 Ω MFC-biosensor. Pseudomonas accounted for 10.73% in 330 Ω MFC-biosensor and possessed the sensitivity to tetracyclines. As for 100 Ω MFC-biosensor, the avermectin-intolerant Ocillibacter made up 2.55% of the anodic microbial community. This study indicated that the R ext of MFC-biosensor should be optimized according to the potential pollutants. Graphical abstract Unlabelled Image Highlights • Optimal external resistance of MFC-biosensor varies with the type of pollutants. • The optimal external resistance for detecting heavy metals is 680 Ω. • The optimal value for avermectins is 100 Ω while 330 Ω for tetracyclines. • The discrepancy is attributed to the differences in anodic microbial communities. [ABSTRACT FROM AUTHOR]

The contribution of external resistance to mass transfer during pasta drying was quantified for a range of pasta properties, extrusion conditions, and drying temperatures. Comparison of drying models showed that neglecting external resistance to mass transfer significantly decreases the accuracy of models during the early stages of drying. A nonlinear uncertainty analysis revealed that failing to consider external resistance to mass transfer results in an underestimation of the effective diffusion coefficient. The Akaike information criterion confirms that external resistance to mass transfer should not be neglected for small pasta or pasta dried at high drying temperatures. [ABSTRACT FROM AUTHOR]

This article explores the case of the French cultural institute in London which found itself at the nexus of Gaullist as well as anti-Gaullist networks during the Second World War. By analysing the support that the institute's director, Denis Saurat, brought to Charles de Gaulle in the early days of Free France, the article contributes to our understanding of the formation of Free French political thought. This study analyses Saurat's shifting position in the movement, from being Gaullist to becoming an active partisan of anti-Gaullism. The examination of Saurat's networks and politics helps to re-appraise further trends of anti-Gaullism caused by leftist views not least regarding the lack of democratic principles that characterized Free France in 1940–2. Finally, Saurat's anti-Gaullism was also prompted by his refusal to put the French cultural institute in London at the service of de Gaulle and support Free French propagandist, cultural and academic ambitions in the world. Overall this article argues for a reassessment of London-based leftist anti-Gaullism understood not just through issues of personalities and democracy but also through the prism of cultural diplomacy and propaganda. [ABSTRACT FROM AUTHOR]

In this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the current, experienced when increasing the external resistance, was maintained even in the reverse scan when the external resistance was step-wise decreased. Regarding the power exerted, when the external resistance was increased below the value of the internal resistance, an enhancement in the power exerted was observed. However, when operating near the value of the internal resistance, a stable power exerted of about 1.6 µW was reached. These current and power responses can be explained by the change in population distribution, which shifts to a more fermentative than electrogenic culture, as was confirmed by the population analyses. Regarding the pollutant removal, the effluent chemical oxygen demand (COD) decreased when the external resistance increased up to the internal resistance value. However, the effluent COD increased when the external resistance was higher than the internal resistance. This behavior was maintained in the reverse scan, which confirmed the modification in the microbial population of the MFC.

Abstract Appropriate inoculation and maturation may be crucial for shortening the startup time and maximising power output of Microbial Fuel Cells (MFCs), whilst ensuring stable operation. In this study we explore the relationship between electrochemical parameters of MFCs matured under different external resistance (R ext) values (50 Ω - 10 kΩ) using non-synthetic fuel (human urine). Maturing the biofilm under the lower selected R ext results in improved power performance and lowest internal resistance (R int), whereas using higher R ext results in increased ohmic losses and inferior performance. When the optimal load is applied to the MFCs following maturity, dependence of microbial activity on original R ext values does not change, suggesting an irreversible effect on the biofilm, within the timeframe of the reported experiments. Biofilm microarchitecture is affected by R ext and plays an important role in MFC efficiency. Presence of water channels, EPS and precipitated salts is distinctive for higher R ext and open circuit MFCs. Correlation analysis reveals that the biofilm changes most dynamically in the first 5 weeks of operation and that fixed R ext lefts an electrochemical effect on biofilm performance. Therefore, the initial conditions of the biofilm development can affect its long-term structure, properties and activity. Graphical abstract Image 1 Highlights • Dynamic changes of biofilm matured under different external loads are investigated. • Most dynamic changes are observed in the first 3 weeks of operation. • External resistance lower than internal resistance improves maturing of the biofilm. • Internal resistance is dependent on external resistance applied in maturing phase. • External resistance irreversibly affects the biofilm properties and performance. [ABSTRACT FROM AUTHOR]

Extraction and analysis of external resistance (${R}_{\textsf {ext}}$) have become increasingly important in modern CMOS technology research. We show that with certain assumptions, the well-known shift-and-ratio method can be extended and still be useful for ${R}_{\textsf {ext}}$ extraction in short-channel devices. Its application to advanced FinFET devices in both simulation and hardware is presented. [ABSTRACT FROM AUTHOR]

The denitrifying sulfide removal microbial fuel cell (MFC) provided an approach for treatment of wastewater containing both sulfide and nitrogenous compounds, but the production of sulfate and nitrite need to be prevented. The interactive effect of electrode potential on sulfide and nitrate conversion was investigated using potentiostatic three-chamber MFC. Both abiotic and biotic processes involved in anodic sulfate formation. Rising anode potential led to an increase of sulfide removal rate and a decrease of sulfur formation percent. The suitable anode potential favoring both sulfide removal and sulfur recovery ranged from −188 mV to −146 mV. The nitrate removal rate and gaseous nitrogen formation percent showed an increase followed by a decrease along with the rise of cathode potential. The suitable cathode potential favoring both nitrate removal and gaseous nitrogen formation ranged from −181 mV to −125 mV. Regulating cathode potential through varying the external resistance was feasible, achieving the optimal sulfur formation percent (32.4 ± 1.9%) and gaseous nitrogen formation percent (92.5 ± 0.3%) at a cathode potential of −139 ± 37 mV. The potentiostatic three-chamber MFC is a suitable configuration for investigating the effect of electrode potential on pollutant conversion because its uncontrolled electrode could simulate the electron driving force situation occurring in a MFC. [ABSTRACT FROM AUTHOR]