Investigation of Perovskite Oxide SrCo _0.8Cu _0.1Nb _0.1O _3–δ as a Cathode Material for Room Temperature Direct Ammonia Fuel Cells

Single‐phase perovskite oxide SrCo0.8Cu0.1Nb0.1O3–δ was synthesized using a Pechini method. X‐ray diffraction (XRD) analysis indicated a cubic structure with a=3.8806(7) Å. The oxide material was combined with active carbon, forming a composite electrode to be used as the cathode in a room temperature ammonia fuel cell based on an anion membrane electrolyte and NiCu/C anode. An open circuit voltage (OCV) of 0.19 V was observed with dilute 0.02 m (340 ppm) ammonia solution as the fuel. The power density and OCV were improved upon the addition of 1 m NaOH to the fuel, suggesting that the addition of NaOH, which could be achieved through the introduction of alkaline waste to the fuel stream, could improve performance when wastewater is used as the fuel. It was found that the SrCo0.8Cu0.1Nb0.1O3−δ cathode was converted from irregular shape into shuttle‐shape during the fuel cell measurements. As the key catalysts for electrode materials for this fuel cell are all inexpensive, after further development, this could be a promising technology for removal of ammonia from wastewater

Effects of Influent Organic Loading Rates and Electrode Locations on the Electrogenesis Capacity of Constructed Wetland-Microbial Fuel Cell Systems

Three novel constructed wetland-microbial fuel cells (CW-MFCs), based on electrode location, were developed for wastewater treatment and sustainable electricity production by embedding a MFC into a CW system. In the three CW-MFCs, electrodes were placed in different locations, including bottom anode-rhizosphere cathode CW-MFC (BA-RC-CW-MFC), rhizosphere anode-air cathode CW-MFC (RA-AC-CW-MFC), and bottom anode-air cathode CW-MFC (BA-AC-CW-MFC), to investigate the combined effects of organic loading rates (OLRs) and reactor configurations on the electrogenesis capacity of the hybrid system. All the systems operated continuously to treat five types of synthetic wastewater with increasing OLRs: 9.2, 18.4, 27.6, 55.2, and 92.0 g chemical oxygen demand (COD) m(-2) d(-1). The BA-RC-CW-MFC failed to produce electricity at any OLR, whereas the maximum power densities of 0.79 +/- 0.01 and 10.77 +/- 0.52 mW m(-2) were achieved in the RA-AC-CW-MFC with 18.4 g COD m(-2) d(-1) influent OLR and in the BA-AC-CW-MFC with 27.6 g COD m(-2) d(-1) influent OLR, respectively. The coulombic efficiencies of the RA-AC-CW-MFC and BA-AC-CW-MFC decreased gradually with the increase in influent OLRs. (C) 2016 American Institute of Chemical Engineers Environ Prog, 36: 435-441, 2017</p

Testing and Data Reduction of the Chinese Small Telescope Array (CSTAR) for Dome A, Antarctica

The Chinese Small Telescope ARray (hereinafter CSTAR) is the first Chinese astronomical instrument on the Antarctic ice cap. The low temperature and low pressure testing of the data acquisition system was carried out in a laboratory refrigerator and on the 4500m Pamirs high plateau, respectively. The results from the final four nights of test observations demonstrated that CSTAR was ready for operation at Dome A, Antarctica. In this paper we present a description of CSTAR and the performance derived from the test observations.Comment: Accepted Research in Astronomy and Astrophysics (RAA) 1 Latex file and 20 figure

Drought stress had a predominant effect over heat stress on three tomato cultivars subjected to combined stress

BACKGROUND: Abiotic stresses due to environmental factors could adversely affect the growth and development of crops. Among the abiotic stresses, drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. Considering global climate change, incidence of combined drought and heat stress is likely to increase. The aim of this study was to shed light on plant growth performance and leaf physiology of three tomatoes cultivars (‘Arvento’, ‘LA1994’ and ‘LA2093’) under control, drought, heat and combined stress. RESULTS: Shoot fresh and dry weight, leaf area and relative water content of all cultivars significantly decreased under drought and combined stress as compared to control. The net photosynthesis and starch content were significantly lower under drought and combined stress than control in the three cultivars. Stomata and pore length of the three cultivars significantly decreased under drought and combined stress as compared to control. The tomato ‘Arvento’ was more affected by heat stress than ‘LA1994’ and ‘LA2093’ due to significant decreases in shoot dry weight, chlorophyll a and carotenoid content, starch content and NPQ (non-photochemical quenching) only in ‘Arvento’ under heat treatment. By comparison, the two heat-tolerant tomatoes were more affected by drought stress compared to ‘Arvento’ as shown by small stomatal and pore area, decreased sucrose content, Φ(PSII) (quantum yield of photosystem II), ETR (electron transport rate) and q(L) (fraction of open PSII centers) in ‘LA1994’ and ‘LA2093’. The three cultivars showed similar response when subjected to the combination of drought and heat stress as shown by most physiological parameters, even though only ‘LA1994’ and ‘LA2093’ showed decreased F(v)/F(m) (maximum potential quantum efficiency of photosystem II), Φ(PSII), ETR and q(L) under combined stress. CONCLUSIONS: The cultivars differing in heat sensitivity did not show difference in the combined stress sensitivity, indicating that selection for tomatoes with combined stress tolerance might not be correlated with the single stress tolerance. In this study, drought stress had a predominant effect on tomato over heat stress, which explained why simultaneous application of heat and drought revealed similar physiological responses to the drought stress. These results will uncover the difference and linkage between the physiological response of tomatoes to drought, heat and combined stress and be important for the selection and breeding of tolerant tomato cultivars under single and combine stress

Isolation of deoxynivalenol-transforming bacteria from the chicken intestines using the approach of PCR-DGGE guided microbial selection

<p>Abstract</p> <p>Background</p> <p>Contamination of grains with trichothecene mycotoxins, especially deoxynivalenol (DON), has been an ongoing problem for Canada and many other countries. Mycotoxin contamination creates food safety risks, reduces grain market values, threatens livestock industries, and limits agricultural produce exports. DON is a secondary metabolite produced by some <it>Fusarium </it>species of fungi. To date, there is a lack of effective and economical methods to significantly reduce the levels of trichothecene mycotoxins in food and feed, including the efforts to breed <it>Fusarium </it>pathogen-resistant crops and chemical/physical treatments to remove the mycotoxins. Biological approaches, such as the use of microorganisms to convert the toxins to non- or less toxic compounds, have become a preferred choice recently due to their high specificity, efficacy, and environmental soundness. However, such approaches are often limited by the availability of microbial agents with the ability to detoxify the mycotoxins. In the present study, an approach with PCR-DGGE guided microbial selection was developed and used to isolate DON -transforming bacteria from chicken intestines, which resulted in the successful isolation of several bacterial isolates that demonstrated the function to transform DON to its de-epoxy form, deepoxy-4-deoxynivalenol (DOM-1), a product much less toxic than DON.</p> <p>Results</p> <p>The use of conventional microbiological selection strategies guided by PCR-DGGE (denaturing gradient gel electrophoresis) bacterial profiles for isolating DON-transforming bacteria has significantly increased the efficiency of the bacterial selection. Ten isolates were identified and isolated from chicken intestines. They were all able to transform DON to DOM-1. Most isolates were potent in transforming DON and the activity was stable during subculturing. Sequence data of partial 16S rRNA genes indicate that the ten isolates belong to four different bacterial groups, Clostridiales, <it>Anaerofilum</it>, <it>Collinsella</it>, and <it>Bacillus</it>.</p> <p>Conclusions</p> <p>The approach with PCR-DGGE guided microbial selection was effective in isolating DON-transforming bacteria and the obtained bacterial isolates were able to transform DON.</p