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In present manuscript, the flow field produced by oscillating foils in a duct were under investigation numerically. The flow field was considered as an incompressible laminar transient flow. In this paper, the oscillating frequencies were 2, 4 and 6 Hz; the span angles of the foil were 30˚, 60˚, 90˚, 120˚, and 150˚, respectively. The flow field produced by a particular oscillating pattern (fast forward slow backward, FFSB) has been made in comparison with that by the sinusoidal oscillating pattern. The flow field produced by dual oscillating foils was also analysed. Two foils oscillated in the same direction (in-phase) and in the opposite direction (counter-phase) were studied as well. Commercial software ANSYS-FLUENT was employed for the 2D numerical simulation. A moving grid technique was utilized in the analysis. Results present the flow average velocity increases as the oscillating frequency increases. It is also shown that the flow average velocity with span angle of 120˚ is the largest among these cases. In addition, the flow average velocity with dual foils is better than that with a single foil.

Summary: Bioaugmentation is considered a potential tool to boost the performance of microbial fuel cells (MFCs) by modifying electrodes with biopolymers. However, research on biopolymers in MFCs to treat real wastewater is very limited. Polylactic acid (PLA) is a biopolymer obtained from renewable feedstock, extensively being used in the form of nanofibers due to its biocompatible nature, while polyaniline (PANI) is a favorite candidate for electrode modification in MFC under its good electrical conductivity and stability. Interestingly, PANI‐based degradable nanofibers are known to support cell adhesion and proliferation. The current work is, therefore, aimed at finding a new environmentally benign composite material using electrospun PLA nanofiber decorated with in situ polymerized PANI. The resultant PANI/PLA electrode was tested for its efficacy as anode with domestic wastewater‐fed MFCs against conventional graphite felt. The flexible anode outperformed the flat graphite felt anode displaying a 92.32% decrement in charge transfer impedance and 8‐fold increase in maximum power density with excellent cell adherence under which simultaneous COD removal of 91.7% was also achieved. The present study has successfully added a new dimension to the design of sustainable anode material to enhance microbial binding and achieve high power output, revealing the enormous potential of biopolymer‐based MFCs in the future. By switching to the biopolymer flexible electrode that rivals its traditional polymers, the MFCs demonstrate promise to be a vital tool accessible in the remotest part of the world lacking electrical infrastructure for simultaneous clean water and electricity generation. Highlights: 8‐fold increase in power density in real wastewater‐fed MFCs using novel PANI/PLA anode.91.7% COD removal from domestic wastewater using mediator‐less MFCs.Pseudocapacitive nature displayed by the biopolymer‐based anode.Enhanced bio‐synergistic interaction between wastewater‐borne microbial biofilm and bioaugmented anode. [ABSTRACT FROM AUTHOR]

Summary: Microbial fuel cells (MFCs) are considered as power generation devices for sustainable energy. However, the power generated is insignificant compared to other energy production devices. In this study, a mini autonomous biosensor (MAB) based on MFCs has been designed for detecting hazardous hexavalent chromium in wastewater. Hexavalent chromium has been classified as a human carcinogen causing serious birth defects due to its mutagenic and teratogenic properties. The power generated by the MAB has been investigated to study the feasibility of providing power to itself. In addition, electrochemical analyses of conductive silver paste and carbon cloth as the anode were conducted in the MAB for detecting hexavalent chromium in the anode chamber. Results show that a maximum voltage of 518.17 mV and a power density of 1.075 mW/cm2 could be achieved using carbon cloth with an external resistance of 1000 Ω, while a higher limiting current density of 0.015 mA/cm2 could be achieved with conductive silver glue as the anode electrode. Besides, the voltage output of the MAB decreased rapidly with the addition of hexavalent chromium into the wastewater. Also, the recovery time for the MAB was much shorter than found in previous studies. The MAB demonstrated potential for simultaneous production of electricity and detection of hexavalent chromium, which would open up avenues for autosensing applications in the environment as well as smart powering devices. Results indicate that the MAB with conductive silver glue as anode electrode is feasible for detecting hexavalent chromium in wastewater. [ABSTRACT FROM AUTHOR]

In our previous studies, a plasma reformer system has been developed to produce syngas containing hydrogen to an electronic fuel injection motorcycle engine. In present investigation, the effect of ignition timing of the engine was considered with an improved spark plug reformer system. The spark plug reformer system included two spark plugs, three supersonic atomizers, a controlling device, and a storage tank. In the experiment, the vehicle under testing was a 1988 c.c. 4 cylinder Nissan Sentra with spark timing 16 BTDC (before top deadcenter). The emission test were tested with HAMA LPS 3000 dynamometer and MTG-5. The ignition timing are 12°, 14°, 16°, 18°, and 20° BTDC. Europe Emission standard cycle was run for the emission test. Results show that the emission of HC decreases and both NO x and CO increase with using the spark plug reforming system without changing the spark timing. The best spark timing of the engine was 14° BTDC, especially for the vehicle operated in high speed. In this operating condition, the HC and NO x decreased and CO 2 increased, however, CO also increased. [ABSTRACT FROM AUTHOR]

The effects of various reaction conditions on a methanol steam reforming (MSR) process were analyzed in this paper by adopting design of experiment (DOE) techniques. The control factors considered are the length and the temperature of the catalyst bed, the steam-to-carbon ratio and the space velocity of the feedstocks, and the catalyst loading within the MSR reactor. The performance indices (quality characteristics) to be analyzed are the methanol conversion, the hydrogen production rate, the CO concentration in the produced mixture, and the ratios of the hydrogen production rate to the methanol feed rate and the catalyst loading, respectively. The major objective of the study is to analyze the holistic influences and the individual significance of the aforementioned reaction conditions on the defined MSR performance indices. Results suggest that temperature is the most significant factor that positively correlates the defined performance indices. The performance of a MSR reactor can be enhanced by raising the reacting temperature. Nonetheless, the CO concentration in the produced mixture is also increased. According to the present work, the effects of the reaction conditions on a MSR process can be analyzed simultaneously meanwhile the optimal combination of the concerned control factors can be obtained. [ABSTRACT FROM AUTHOR]