Effects of Vertical and Horizontal Configurations of Different Numbers of Brush Anodes on Performance and Electrochemistry of Microbial Fuel Cells

( Huong V. H. Tran ),( Sokhee P. Jung ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

To maximize wastewater treatment and energy production by microbial fuel cells (MFCs), it is important to design the optimal anode arrangement. In this study, four brushes were tested horizontally or vertically to the cathode as the number of the anodes increased from one to four. In the horizontal configuration, adding the anodes greatly reduce electrode resistance and enhanced cell performance, showing four anodes (H4) was the best. In the vertical configuration, two anodes (V2) showed greatest performance and greatest decrease in anode resistance. Compared with one anode, maximum power increased by 59% in H4 and by 18% in V2; anode polarization resistance decreased by 95% in H4 and by 74% in V2; anode impedance decreased by 91% in H2 and by 73% in V2. Cathode resistance was relatively constant, showing adding anodes had negligible effect on it. Because diffusion resistance increases with increasing distance between an anode and a cathode, the vertical anodes should have different diffusion resistance and performances. In this study, adding more anodes vertically decreased cell performance in V3 and V4. However, in a cyclic voltammetry test, current production was substantially increased when the third and the fourth brush anodes were introduced in the both arrangements. Compared with one anode, current production increased by 200% in H4 and by 205% in V4. It shows that the external electrical input relieved diffusion resistance and increased current generation and that installing anodes away from the cathode is a good strategy to increase current production in a system with external power supply such as microbial electrolysis cell. Based on the results, we suggest the following strategy: i) install multiple anodes horizontally along the cathode; ii) install multiple anodes in the second row horizontally along the cathode; iii) install multiple anodes both horizontally and vertically if there is an external power supply.

Fast response of sprayed vanadium pentoxide (V₂O₅) nanorods towards nitrogen dioxide (NO₂) gas detection

Mane, A.A.,Suryawanshi, M.P.,Kim, J.H.,Moholkar, A.V. Elsevier BV * North-Holland 2017 Applied Surface Science Vol.403 No.-

<P><B>Abstract</B></P> <P>The V<SUB>2</SUB>O<SUB>5</SUB> nanorods have been successfully spray deposited at optimized substrate temperature of 400°C onto the glass substrates using vanadium trichloride (VCl<SUB>3</SUB>) solution of different concentrations. The effect of solution concentration on the physicochemical and NO<SUB>2</SUB> gas sensing properties of sprayed V<SUB>2</SUB>O<SUB>5</SUB> nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V<SUB>2</SUB>O<SUB>5</SUB> having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V<SUB>2</SUB>O<SUB>5</SUB>. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45eV to 2.42eV. The nanorods deposited with 30mM solution concentration shows the maximum response of 24.2% for 100ppm NO<SUB>2</SUB> gas concentration at an operating temperature of 200°C with response and recovery times of 13s and 140s, respectively. Finally, the chemisorption mechanism of NO<SUB>2</SUB> gas on the V<SUB>2</SUB>O<SUB>5</SUB> nanorods is discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of solution concentration on physicochemical properties of sprayed V<SUB>2</SUB>O<SUB>5</SUB> nanorods is studied. </LI> <LI> Good re­sponse and short re­sponse- re­covery times of V<SUB>2</SUB>O<SUB>5</SUB> nanorods towards NO<SUB>2</SUB> gas show it is potential material for fab­ri­ca­tion of NO<SUB>2</SUB> sensor. </LI> <LI> The chemisorption mechanism of NO<SUB>2</SUB> gas on the V<SUB>2</SUB>O<SUB>5</SUB> nanorods is discussed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The evolutionary dynamics of highly pathogenic avian influenza H5N1 in south-central Vietnam reveals multiple clades evolving from Chinese and Cambodian viruses

Nguyen, T.H.,Than, V.T.,Thanh, H.D.,Nguyen, V.Q.,Nguyen, K.H.,Nguyen, D.T.,Park, J.H.,Chung, I.S.,Jeong, D.G.,Chang, K.T.,Oh, T.K.,Kim, W. Pergamon Press 2015 Comparative immunology, microbiology and infectiou Vol.42 No.-

In Vietnam, highly pathogenic avian influenza (HPAI), such as that caused by H5N1 viruses, is the most highly contagious infectious disease that has been affecting domestic poultry in recent years. Vietnam might be an evolutionary hotspot and a potential source of globally pandemic strains. However, few studies have reported viruses circulating in the south-central region of Vietnam. In the present study, 47 H5N1-positive samples were collected from both vaccinated and unvaccinated poultry farms in the South Central Coast region of Vietnam during 2013-2014, and their genetic diversity was analyzed. A common sequence motif for HPAI virus was identified at HA-cleavage sites in all samples: either RERRRKR/G (clades 2.3.2.1c and 2.3.2.1a) or REGRRKKR/G (clade 1.1.2). Phylogenetic analysis of HA genes identified three clades of HPAI H5N1: 1.1.2 (n=1), 2.3.2.1a (n=1), and 2.3.2.1c (n=45). The phylogenetic analysis indicated that these Vietnamese clades may have evolved from Chinese and Cambodian virus clades isolated in 2012-2013 but are less closely related to the clades detected from the Tyva Republic, Bulgaria, Mongolia, Japan, and Korea in 2009-2011. Detection of the coexistence of virus clades 2.3.2.1 and the very virulent 1.1.2 in the south-central regions suggests their local importance and highlights concerns regarding their spread, both northwards and southwards, as well as the potential for reassortment. The obtained data highlight the importance of regular identification of viral evolution and the development and use of region-specific vaccines.

The Histone Modification Domain of Paf1 Complex Subunit Rtf1 Directly Stimulates H2B Ubiquitylation through an Interaction with Rad6

Van Oss, S. Branden,Shirra, Margaret K.,Bataille, Alain R.,Wier, Adam D.,Yen, Kuangyu,Vinayachandran, Vinesh,Byeon, In-Ja L.,Cucinotta, Christine E.,Hé,roux, Annie,Jeon, Jongcheol,Kim, Jaehoon,V Elsevier 2016 Molecular cell Vol.64 No.4

<P><B>Summary</B></P> <P>The five-subunit yeast Paf1 complex (Paf1C) regulates all stages of transcription and is critical for the monoubiquitylation of histone H2B (H2Bub), a modification that broadly influences chromatin structure and eukaryotic transcription. Here, we show that the histone modification domain (HMD) of Paf1C subunit Rtf1 directly interacts with the ubiquitin conjugase Rad6 and stimulates H2Bub independently of transcription. We present the crystal structure of the Rtf1 HMD and use site-specific, in vivo crosslinking to identify a conserved Rad6 interaction surface. Utilizing ChIP-exo analysis, we define the localization patterns of the H2Bub machinery at high resolution and demonstrate the importance of Paf1C in targeting the Rtf1 HMD, and thereby H2Bub, to its appropriate genomic locations. Finally, we observe HMD-dependent stimulation of H2Bub in a transcription-free, reconstituted in vitro system. Taken together, our results argue for an active role for Paf1C in promoting H2Bub and ensuring its proper localization in vivo.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Histone modification domain (HMD) of Rtf1 directly contacts Rad6 in vivo </LI> <LI> HMD structure and in vivo crosslinking identify a conserved Rad6 interaction surface </LI> <LI> Paf1C regulates global H2B ubiquitylation (ub) patterns by linking HMD to Pol II </LI> <LI> HMD stimulates Bre1-dependent H2Bub in a transcription-free, reconstituted assay </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Search for lepton flavor and lepton number violating <i>τ</i> decays into a lepton and two charged mesons

Miyazaki, Y.,Aihara, H.,Arinstein, K.,Aulchenko, V.,Aushev, T.,Bakich, A.M.,Balagura, V.,Barberio, E.,Bay, A.,Belous, K.,Bhardwaj, V.,Bischofberger, M.,Bondar, A.,Brač,ko, M.,Browder, T.E.,Chang, North-Holland Pub. Co 2010 Physics letters. Section B Vol.682 No.4

<P><B>Abstract</B></P><P>We search for lepton flavor and lepton number violating <I>τ</I> decays into a lepton (ℓ=electron or muon) and two charged mesons (h,<SUP>h′</SUP>=<SUP>π±</SUP> or <SUP>K±</SUP>), <SUP>τ−</SUP>→<SUP>ℓ−</SUP><SUP>h+</SUP><SUP>h′−</SUP> and <SUP>τ−</SUP>→<SUP>ℓ+</SUP><SUP>h−</SUP><SUP>h′−</SUP>, using 671 fb<SUP>−1</SUP> of data collected with the Belle detector at the KEKB asymmetric-energy <SUP>e+</SUP><SUP>e−</SUP> collider. We obtain 90% C.L. upper limits on the branching fractions in the range (4.4–8.8)×<SUP>10−8</SUP> for τ→eh<SUP>h′</SUP>, and (3.3–16)×<SUP>10−8</SUP> for τ→μh<SUP>h′</SUP> processes. These results improve upon previously published upper limits by factors between 1.6 to 8.8.</P>

Decomposition of hydrogen sulfide (H₂S) on Ni(100) and Ni₃Al(100) surfaces from first-principles

Hernandez, J.M.,Lim, D.H.,Nguyen, H.V.P.,Yoon, S.P.,Han, J.,Nam, S.W.,Yoon, C.W.,Kim, S.K.,Ham, H.C. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.23

Spin-polarized density functional theory studies of hydrogen sulfide (H<SUB>2</SUB>S) adsorption and decomposition on Ni(100) and Ni<SUB>3</SUB>Al(100) surfaces were conducted to understand the aluminum (Al) alloying effect on H<SUB>2</SUB>S dissociation. For such purpose, we first determined the near surface structure of fully ordered Ni<SUB>3</SUB>Al alloy along the [100] direction by calculating the Al segregation energy to the surface and then examined the adsorption energies of the adsorbates (H<SUB>2</SUB>S, HS, S, and H) and the activation barriers for the H<SUB>2</SUB>S and HS decomposition by using Climbing Image-Nudged Elastic Band method. We found that regardless of the way to terminate the surface, Al atom in bimetallic Ni<SUB>3</SUB>Al(100) tends to exist in the first surface layer, rather than in the second or third layer, and the Ni<SUB>3</SUB>Al(100) surface can substantially retard the H<SUB>2</SUB>S decomposition by reducing the adsorption energy of sulfur compounds compared to the pure Ni(100) case. Finally, we presented how the Al in Ni<SUB>3</SUB>Al modifies the activity of surface Ni atoms toward the sulfur compounds by calculating the local density of states and charge distribution in alloying components. This work hints the importance of knowing how to properly tailor the reactivity of Ni based materials to enhance the resistance for sulfur poisoning.

Deep hole traps in undoped n-GaN films grown by hydride vapor phase epitaxy

Lee, In-Hwan,Polyakov, A. Y.,Smirnov, N. B.,Govorkov, A. V.,Usikov, A. S.,Helava, H.,Makarov, Yu. N.,Pearton, S. J. American Institute of Physics 2014 JOURNAL OF APPLIED PHYSICS - Vol.115 No.22

Deep hole traps were studied in bulk free-standing GaN crystals and in thinner (10-20 mu m) GaN films prepared by hydride vapor phase epitaxy (HVPE) on sapphire. Six hole traps in different combinations were detected in these crystals, H1 (activation energy 0.92-0.94 eV), H2 (0.55 eV), H3 (0.65-0.7 eV), H4 (0.85-0.9 eV), H5 (1.1-1.2 eV), and H6 (0.95-1.05 eV). The dominant traps in all samples were the H5 and H6 traps that were attributed, respectively, to gallium vacancy complexes with oxygen (V-Ga-O) and substitutional carbon related centers. We associate the H5 hole traps with the red luminescence bands, the H4 hole traps with the green luminescence bands, and the H6 hole traps with the yellow luminescence bands often observed in HVPE GaN. These attributions are based on the low energy thresholds of the deep traps optical excitation spectra and the depth of the respective trap levels. (C) 2014 AIP Publishing LLC.

Prevalence of Haplorchis taichui among humans and fish in Luang Prabang Province, Lao PDR

Sohn, W.M.,Yong, T.S.,Eom, K.S.,Min, D.Y.,Lee, D.,Jung, B.K.,Banouvong, V.,Insisiengmay, B.,Phommasack, B.,Rim, H.J.,Chai, J.Y. Verlag für Recht und Gesellschaft ; Elsevier 2014 Acta tropica Vol.136 No.-

This study confirmed the prevalence of the intestinal fluke Haplorchis taichui (Trematoda: Heterophyidae) among people and fish in Luang Prabang Province, Lao PDR. Fecal specimens were collected from 559 riparian people (229 males and 330 females), residing in 4 Districts (Luang Prabang, Xieng Ngeun, Pak Ou, and Nam Bak) and were examined by the Kato-Katz fecal smear technique. The overall helminth egg positive rate was 64.9%. The positive rate for small trematode eggs (STE), which may include H. taichui and other heterophyids, Opisthorchis viverrini, and lecithodendriids, was 15.2%. For recovery of adult helminths, 10 STE-positive people were treated with 40mg/kg praziquantel and 15mg/kg pyrantel pamoate, and then purged. Mixed infections with 3 Haplorchis species (H. taichui, H. pumilio, and H. yokogawai), a species of cestode (Taenia saginata), and several species of nematodes including Enterobius vermicularis and hookworms were found. The worm load for trematodes was exclusively high for H. taichui with an average of 7691 specimens per infected person, followed by H. yokogawai (8.3 specimens) and H. pumilio (4.1 specimens). Out of 207 freshwater fish (17 species) purchased in a market in Luang Prabang District, 138 (67%) harboured H. taichui metacercariae (metacercarial burden per fish; 520). Lower prevalence of fish and lower metacercarial density were observed for H. yokogawai (52% and 50 per fish, respectively) and H. pumilio (18% and 3 per fish, respectively). STE found in the surveyed population of Luang Prabang Province were verified to be those of intestinal fukes, particularly H. taichui.

Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pentoxide nanorods for detection of nitrogen dioxide gas

Mane, A.A.,Suryawanshi, M.P.,Kim, J.H.,Moholkar, A.V. Academic Press 2017 Journal of Colloid and Interface Science Vol. No.

<P><B>Abstract</B></P> <P>Vanadium pentoxide (V<SUB>2</SUB>O<SUB>5</SUB>) nanorods have been deposited onto the glass substrates by spraying 75ml of 30mM vanadium trichloride (VCl<SUB>3</SUB>) solution at optimized substrate temperature of 400°C. The XRD study confirms the formation of orthorhombic crystal structure of V<SUB>2</SUB>O<SUB>5</SUB> nanorods. The FE-SEM micrograph shows the nanorods-like morphology of V<SUB>2</SUB>O<SUB>5</SUB>. The presence of palladium (Pd) in the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> nanorods is confirmed using EDAX study. The gas sensing measurements show that the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> sensing material is an outstanding candidate for nitrogen dioxide (NO<SUB>2</SUB>) gas detection. Obtained results demonstrate that the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> nanorods show the superior selectivity for NO<SUB>2</SUB> gas in comparison with other gases such as NH<SUB>3</SUB>, H<SUB>2</SUB>S, CO, CO<SUB>2</SUB> and SO<SUB>2</SUB> at an operating temperature of 200°C. It shows the 75% response for 100ppm NO<SUB>2</SUB> gas concentration with response and recovery times of 22s and 126s, respectively. Finally, the gas sensing mechanism based on chemisorption process is proposed to illustrate how Pd nanoparticles affect the gas sensing characteristics (response and response-recovery times).</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

MCFC fed with biogas: Experimental investigation of sulphur poisoning using impedance spectroscopy

Cigolotti, V.,McPhail, S.,Moreno, A.,Yoon, S.P.,Han, J.H.,Nam, S.W.,Lim, T.H. Pergamon Press ; Elsevier Science Ltd 2011 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.36 No.16

The combination of biogas from anaerobic digestion and molten carbonate fuel cell (MCFC) enables highly efficient utilisation of a renewable energy source, maximizing the energetic yield from alternative fuels and minimizing environmental impact in terms of polluting emissions. However, the contaminant levels in the biogas are often unacceptable for performing and durable operation of an MCFC; it is thus desirable to establish and improve the tolerance level of the fuel cell to these contaminants. In this work, the effect of hydrogen sulphide (H<SUB>2</SUB>S) in the fuel gas is investigated on the electrochemical performance and the regenerative capacities of a single MCFC. Different concentrations of H<SUB>2</SUB>S (1, 3, 5, 8 ppm) were added to the anode gas composition during cell operation and the respective effects are investigated. Electrochemical impedance measurements are carried out to identify the processes which take place in the anode. Experimental results will be presented, showing the effects and implications of cell poisoning with H<SUB>2</SUB>S, the most common contaminant from biogas produced by anaerobic digestion, harmful to both the MCFC anode and the reforming catalyst. This investigation is required in order to identify the tolerance limits of current MCFC materials, especially as regards different concentrations of H<SUB>2</SUB>S that can occur due to composition variations of the produced biogas.