In order to analyze the effect of cathode’s Pt loading side on the performance of single-chamber microbial fuel cells (MFCs), power generation of a bamboo charcoal membrane-less air-cathode MFC was ...examined. The maximum power outputs obtained were 0.144 and 1.16
mW, while the maximum voltage outputs were 0.400 and 0.500
V (external resistance was 500
Ω), respectively, when the Pt loading side facing to the air and to the anode chamber solution; after a long time of operation with the side of cathode loaded Pt facing to anode chamber solution, a biofilm was developed on the inner side of cathode. With the formation of this biofilm, the power outputs of MFC increased first, and then decreased to 0.8
mW; oxidation–reduction potentials (ORP) dropped first, and then achieved the level of stability. Coulombic efficiency (CE) increased at a certain extent. In addition, the impact of cathode-biofilm on the loss of water in anode chamber solution was determined.
With biocompatibility and biodegradability, self-healing hydrogels prepared from biopolymers show great advantages in bioengineering and bioscience as drug delivery carrier. In this research, the ...biodegradable hydrogel was constructed based on poly(amino acid) of poly(aspartic acid) (PAsp) and pectin for in vivo antitumor applications as DOX release carrier. The PAsp bearing hydrazide groups and isopropyl groups (PAPH) was synthesized by ring opening of polysuccinimide (PSI) by isopropylamine and hydrazine, and used to fabricate fully biodegradable hydrogel with oxidized pectin (OPec) through dynamic acylhydrazone bond cross-linking. The regulatable mechanical strength of the hydrogel could adapt its bioapplication, and the excellent biocompatibility ensured biosafety in biomedical areas. Furthermore, the pectin backbone and the PAsp endowed the hydrogel with biodegradability both by enzyme and in vivo. The PAPH/Opec hydrogel as DOX carrier inhibited the tumor growth with the tumor weight 80% lower than the control group and reduced the in vivo toxicity of the DOX. As a result, this biodegradable PAPH/Opec hydrogel could find show great potential as sustained drug delivery vehicle in biomedical areas.
This study focused on providing power for implantable medical devices (IMDs) using a microbial fuel cell (MFC) implanted in human transverse colon. Considering the condition of colonic environment, a ...continuous-flow single-chamber MFC without membrane was set up. The performance of the MFC was investigated. The power output of 1.6mW under the steady state was not rich enough for some high energy-consuming IMDs. Moreover, the parameters of the simulated colonic environment, such as pH and ORP value, varied along with the time. Hence, a new MFC configuration was developed. In this novel model, pH transducers were placed in cathodic and anodic areas, so as to regulate the reactor operation timely via external intervention. And two ORP transducers were inserted next to the pH transducers, for monitoring and adjusting the MFC operation efficiently. Besides, colonic haustra were designed in order to increase the difference between cathodic and anodic areas.
► Further investigate the feasibility of supplying power for IMDs using MFC. ► A new configuration of MFC was designed. ► It could simulate the colonic environment better. ► A real-time measurement system was constructed in the MFC.
In this paper, a new “convex” external magnetic pole structure is proposed. With this structure, two different configurations of the cathode inside and outside the magnetic separatrix can be realized ...by changing the position of the magnetic separatrix instead of changing the position of the cathode in the radial direction. Furthermore, the discharge plume, coupling voltage, and performance of the thruster under different configuration conditions are studied experimentally. The experimental results indicate that, when the cathode is located inside the magnetic separatrix, the effective acceleration voltage is higher, the coupling voltage between the cathode and the thruster is lower, and the thruster performance (including thrust, specific impulse, and efficiency) is higher. When the cathode is located outside the magnetic separatrix, the effective acceleration voltage is lower, the coupling voltage between the cathode and the thruster is higher, and the thruster performance is degraded. When the cathode is located inside the magnetic separatrix, the thrust and specific impulse can be increased up to 2.3%, and the efficiency—up to 4.6%. This study provides a new method for the design of the magnetic separatrix and is of great importance for the coupling-matching design of the cathode and thruster.
•A new “convex” external magnetic pole structure is proposed.•Discharge characteristic of Hall thrusters is studied under different configurations.•A method for coupling-matching design of the cathode and thruster is provided.
► We designed a new membraneless microbial fuel cell structure and operation model to lower the cost. ► Protons in this model transfer via electrolyte flow, which is more efficient than via ...membranes. ► The output of this MFC can reach 24.33mW/m3, and the internal resistance is about 5000Ω. ► COD removal efficiency after the treatment of this system is 90.45% at flow rate of 25mL/min. ► This model can be used in Anaerobic/Oxic or Anaerobic/Anoxic/Oxic wastewater treatment process.
Microbial fuel cell (MFC) is an emerging technology in the energy and environment field. Its application is limited due to its high cost caused by the utilization of membranes and noble metal catalysts. In this paper, a membraneless MFC, with separated electrode chambers, was designed. The two separated chambers are connected via a channel and the continuous electrolyte flow from anode to cathode drives proton transfer. The proton mass transfer coefficiency in this MFC is 0.9086cm/s, which is higher than reported MFCs with membranes, such as J-cloth and glass fiber. The maximum output voltage is 160.7mV, with 1000Ω resistor. Its peak power density is 24.33mW/m3. SCOD removal efficiency can reach 90.45% via this MFC. If the connection between the two electrode chambers is blocked, the performance of MFC will decrease severely. All the above results prove the feasibility and advantages of this special MFC model.
Using Microbial fuel cell (MFC) to convert organic and inorganic matter into electricity is of great interest for powering portable devices, which is now still limited by the output of MFC. In this ...study, a spiral wound MFC (SWMFC) with relatively large volume normalized surface area of separator (4.2cm2/ml) was fabricated to enhance power generation. Compared with double-membrane MFC (DMMFC) and conventional double chamber MFC (DCMFC), the power density of SWMFC increased by 42% and 99% resulted from its lower internal resistance. Besides larger separator area, the better performance of SWMFC benefited from its structure sandwiching the cathodes between two separators. This point was proved again by a comparison of another DCMFC and a triple chamber MFC (TCMFC) as well as a simulation using finite element method. Moreover, the feature of SWMFC was more convenient and compact to scale up. Therefore, SWMFC provides a promising configuration for high power output as a portable power source.
► The spiral wound microbial fuel cell (SWMFC) was firstly designed. ► Double power density was obtained compared with the conventional configuration. ► The improvement of power output benefited from its lower ohmic resistances. ► This structure could be scaled up conveniently.
Nickel-based activated carbon was prepared from coconut shell activated carbon by electroless plating with palladium-free activation. The materials were characterized by scanning electron microscopy ...(SEM), X-ray energy dispersion spectroscopy (EDS), vibrating sample magnetometry (VSM), and vector network analyzer, respectively. The results show that the surface of the activated carbon was covered by a Ni-P coating, which was uniform, compact, and continuous and had an obvious metallic sheen. The content of P and Ni was 2.73% and 97.27% in the coating. Compared with the untreated activated carbon, the real permeability μ′ and imaginary permeability μ″ of Ni-based activated carbon became greater, whereas the real permittivity ε′ and imaginary permittivity ε″ became smaller. Also, the plated activated carbon was magnetic, making it suitable for some special applications. In general, the method reported here might be a feasible procedure to coat activated carbon with other magnetic metals, which may find application in various areas.
This letter mainly considers the environmental clutter problem in distinguishing between stationary humans and animals through-wall circumstances. Focusing on the challenges of object identification ...in the time-frequency map, we propose a cross-scale feature aggregation (CSFA) network based on channel-spatial attention, which can improve the identification accuracy of stationary humans and animals. Specifically, life detection radar is utilized to collect data, and the time-frequency analysis method synchrosqueezing transform (SST) is used to suppress the signal noise and generate higher-resolution time-frequency maps. In order to make full use of the target information, we use a feature pyramid network (FPN) to obtain multilevel feature information maps from time-frequency maps. Then, the CSFA module is utilized to extract detailed micro-Doppler feature information from feature maps. And we use a deep convolutional neural network (CNN) to classify humans from animals. Experimental results show that the proposed model has a better performance in accuracy compared with the existing methods.
This letter considers the coherent integration problem for a maneuvering target in low signal-to-noise-ratio (SNR) circumstances. Focusing on the range migration (RM) and Doppler frequency migration ...(DFM) problems caused by the motion of the target, we propose a new method called Radon-general linear chirplet transform (RGLCT). Jointly motion parameters search is employed to obtain the trajectory of the maneuvering target and the coherent integration is achieved via general linear chirplet transform (GLCT). Because of the nonsensitive-to-noise feature of the GLCT, RGLCT can realize weak target coherent integration in very low SNR environments. Multitarget detection can be achieved successfully because the GLCT is not influenced by the cross-term components. Finally, simulations and real data experiments are performed to demonstrate the effectiveness of the method. The results show that the proposed method has superior detection ability than methods, including Radon-Fourier transform (RFT) and Radon-Lv's distribution (RLVD). Both theory and experiments have fully proved that the proposed method can effectively realize coherent integration in low SNR environments.
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•TP, OP, labile P and EHOP in the WLFZ soil decreased after frequent DRW.•Pmic, OM and Feox are key factors affecting the increase of labile P after DRW.•DRW changed the proportions ...of the various fractions of soil organic P.•Source proportions for the increased labile P after DRW were determined.
The water-level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China has been frequently subjected to drying and rewetting (DRW) since the construction of the Three Gorges Dam. The increased soil labile phosphorus (P) after DRW potentially increases the risk of the release of soil P from the WLFZ to the reservoir water. Our study explored the effects of DRW on the P status of WLFZ soils. In June 2018, surface soil (0–2 cm) samples were taken in the WLFZ at two altitudes of in a tributary (Pengxi River) of the TGR. The labile P and the soil properties were determined in both field-moist and air-dried soils, and the organic P fractions in the bicarbonate extracts were determined through enzymatic hydrolysis. In addition, the contributions of various sources to the increase of soil labile P after DRW were quantified by using the improved organic P fractions tracing method. The results showed that the contents of TP, OP, Olsen-TP, Olsen-IP, Olsen-OP and the proportion of bioavailable P in the field-moist soils at 145 m were significantly lower than those at 165 m. Inorganic P was the main contributor to the increase in P in the bicarbonate extractants following DRW. Pmic, OM and Feox were found to be the main factors influencing the increase in soil labile P after DRW. The organic P fractions, such as diester P, phytate-like P and unknown P, also increased significantly after DRW. The transformation of slowly cycling P contributed 78% and 51% to the increase in Olsen-TP at 145 m and 165 m, respectively, and the death of microorganisms contributed 16% and 18%. The proposed method to quantify the source of increased soil labile P after DRW potentially contributes to reduce the release risk of P from the continent to the receiving aquatic systems.
