Assuming a series-type microbial fuel cell (MFC) that sequentially consumes organic acid components, the effects of the electrode material, external resistance, and temperature of MFC on the ...decomposition characteristics of acetate and propionate were investigated. As to electrode materials, propionate decomposition required less time in carbon cloth (CC) than that in carbon felt (CF), and maximum power was produced higher in CC than that in CF as well as acetate substrate. When the external resistance of 1000 Ω was replaced with 100 Ω or 10 Ω, both the decomposition rate and maximum power in propionate were lower than those in acetate, respectively. The time required for acetate decomposition at the temperature of 30 °C and 37 °C was 14.8 and 19.4 h, while 25.3 and 17.2 h in propionate at 30 °C and 37 °C, respectively. The microbial community changed significantly between 30 °C and 37 °C of the temperature.
•Electrode material and external resistance of MFC influenced the decomposition rate of propionate.•The change in reactor temperature was the most influential factor in the propionate decomposition.•The dominant species of δ-proteobacteria in the propionate at 37 °C was Desulfobulbus elongates.
The objective of this study was to manufacture of a granular biochar-ammonium phosphate (BAP) as an uncoated-slow release fertilizer by using the reaction among biochar (derived from rice husk), ...phosphoric acid and ammonia gas for fertilization of sandy soil. In this study we assessed the influence of two types of BAP {1.5 mol NH3+(0.76 molH3PO4+150 g biochar) BAP1and 1.5 mol NH3+(0.76 mol H3PO4+220 g biochar) BAP2} on nitrogen (N) use efficiency (NUE) and N losses in leachate water and compared them to a conventional mineral N fertilizer (ammonium phosphate, AP). Additionally the surface morphology of biochar, BAP1 and BAP2 was examined by scanning electron microscopy (SEM) and Fourier transfer infra-red (FT-IR). SEM and FT-IR confirmed the formation of ammonium phosphate inside the biochar's pores. Release of the available nitrogen (NH+4 -H and NO−3- H) from both BAP1 and BAP2 fertilizers was detected to be slow and low compared with AP fertilizer. pots treated with either BAP1 or BAP2 demonstrated fundamentally higher (p < 0.05) N content and vegetative improvement compared with AP, however no critical difference (p > 0.05) were found among BAP1 and BAP2 fertilizers. Correspondingly, the synthesis of this new fertilizer using this technology provided a unique organic matter in the manufacture of uncoated-slow release fertilizer. Subsequently, BAP could be used as an uncoated-slow release fertilizer to maximize the functions of the nitrogen fertilizer when added to a sandy soil and minimize its environmental impact.
Hydrogen is the promising ideal energy carrier with no emission but water on its combustible in the next generation. Hydrogen production using biological methods is greener than other methods using ...fossil fuel. One of the major factors affecting the operation of biohydrogen production is pH level in bioreactors. Restrain of declining pH is expected to increase hydrogen production. Pretreatment is one key factor in successful biohydrogen fermentation using mixed microbes. This study aims to investigate the natural buffer effect on biohydrogen using hot compressed water pretreatment. This batch fermentation experiment was operated in a 110 mL glass reactor with 3.75 g/L glucose as substrate. Mixed culture was obtained from cow dung compost treated with hot compressed water pretreatment at 150 ºC, 0.5 MPa for 40 minutes. Fine dried eggshell powder and calcinated eggshell were added with 1 g/L, 3 g/L, and 5 g/L concentrations as buffer agents. The result showed that the addition of 1 g/L eggshell obtained the highest hydrogen production rate of 0.92 mol H2/mol glucose. Butyric acid and acetic acid are recognized as an indicator of hydrogen production and the Butyric/Acetic molar ratio over 2.6 as efficient biohydrogen fermentation. The highest B/A ratio in this experiment was 4.62 on 3g/L addition of eggshell powder.
Air-assisted rice seeders were designed to perform sowing while ensuring the alignment and depth of seeds within the allowable standard range of 5–10 mm. Their performance varies on the basis of ...different specifications; thus, it is necessary to evaluate them to select the best one. Fuzzy set theory allows us to flexibly handle practical problems, especially applied problems in engineering. In this paper, a new similarity measure using fuzzy sets is proposed, and its advantages were tested using the technique for order preference by similarity to ideal solution (TOPSIS) method to select technical parameters for the sowing machines. The experiments allowed identifying the best results. The correlations between input attributes and decision variables were determined on the basis of their correlation coefficients with technical factors. The influence of technical factors on output results was also examined to determine the technical factors providing superior product quality.
Most hydrogen is derived from fossil fuels. Therefore, more environmentally friendly methods for hydrogen production have been investigated. The present report describes a hot compressed water (HCW) ...pretreatment to increase hydrogen production using sake lees, which is an industrial waste of sake production. The inoculum is obtained from treated biogas slurry. The temperatures of HCW are 130 (0.3 MPa), 150 (0.5 MPa), and 180 °C (0.8 MPa) for 15–120 min. Gas production was analyzed using gas chromatography; fermentation liquid analyses were performed using HPLC. The modified Gompertz model was used to determine hydrogen potential, lag time, and production rate. Results show an increase in the degradation of sake lees with longer holding time and higher temperature. Total sugar and organic acids also are influenced by HCW pretreatment. The maximum hydrogen yield was obtained at 130 °C for 60 min with the result 112.07 mL H2/g COD. The HCW pretreatment successfully decreased the lag phase of biohydrogen production and increased the degree of acidification. Clostridium butyricum, C. acetobutylicum, and other Clostridium sp. were identified in all samples, while Pantoea agglomerans was detected in two samples.
•The Hot Compressed water (HCW) treatment increase biohydrogen production.•The high HCW temperature and long holding time increase the degradation rate.•HCW treatment lessen the lag time of fermentation & increase the acidification degree.•P. agglomerans and Clostridium sp. synergize in the biohydrogen fermentation.
Recirculated two-phase anaerobic digestion (RTAD) is a recent technique to improve biogas production. Recirculating the effluent of two-phase anaerobic system has a methanogens invasion risk to dark ...fermentation. Hot compressed water is possible to reduce the methanogens invasion. The objectives of this study are identifying the effect of hot compressed water pretreatment on RTAD and evaluating the fermentation system during the change of hydraulic retention time and effluent recirculation ratio. The RTAD system was built and operated with 4 different conditions, those are hydraulic retention time 2-day (HRT 2d), HRT 3d, Effluent Ratio 1:5 (R1:5) and R2:5. The result shows that the shorter HRT increase the biogas production. The pH in the reactor is more stable after the recirculation process. In bioreactor performance, the hot compressed water treatment increased the COD removal at all conditions. The highest COD removal achieved at condition of HRT 2-day with removal up to 94.5%. The system that using hot compressed water treatment has the higher energy potential at HRT 2-day, R 1:5 and R 2:5 compared with no hot compressed water treatment.
•RTPAD using Hot Compressed water (HCW) treatment.•H2 and CH4 improvement using RTPAD system.•Bioreactor performance on RTPAD using HCW treatment.•Biohydrogen production on continuous fermentation system.
We evaluated an air-assisted strip seeder, developed by the Hokuriku research center, in farmers’ fields for four years. Plantings using the seeder had more panicles and a higher yield than those ...using a shooting hill-seeder. The early growth of planting using the air-assisted strip seeder was promoted by increasing the rate of seedling establishment because the seeding depth of plantings using the air-assisted strip seeder was shallower than that of plantings using the shooting hill-seeder. Tillering in this planting was also promoted, which boosted the yield, while simultaneous seeding with fertilizer application using the air-assisted strip seeder was also compared with conventional practice over two years in a field at the Hokuriku research center. During simultaneous seeding with fertilizer application, the rate of seedling establishment was equivalent to that in conventional practice. After seedling establishment, growth and yields in the simultaneous seeding with fertilizer application were equivalent to or exceeded those in conventional practice.
A long-term, sustainable solution to weed infestation is extremely desirable because weeds have the potential to reduce crop productivity and the aesthetic appeal of the environment. In this study, ...the impacts of mowing and varying degrees of trampling pressure on the suppression of weeds, alongside wound-induced changes in the allelopathic potential, of the rhizosphere soil and the root exudates of southern crabgrass (Digitaria ciliaris) and Asian flatsedge (Cyperus microiria) were evaluated under both field and greenhouse conditions. The field study results showed that all trampling treatments induced the relative suppression of weed growth. Grass weeds showed higher resistance to trampling than broad-leaved weeds. However, laboratory bioassays showed that light trampling caused a significant increase in the growth-inhibitory effects of southern crabgrass rhizosphere soil on lettuce. Moreover, mowing (9.11% of control) and trampling (16.4% of control) resulted in a marginal increase in the growth-inhibitory effects of root exudates released from southern crabgrass. Furthermore, the growth-inhibitory activities of the Asian flatsedge rhizosphere soil were significantly reduced after heavy trampling pressure. Moreover, mowing and trampling resulted in marginal reductions in the growth-inhibitory activities of root exudates released from Asian flatsedge against lettuce (i.e., 18.7% and 28.5%, respectively). In general, mowing and varying degrees of trampling induced contrasting and integrated impacts on weed suppression as well as the allelopathic potential of both southern crabgrass and Asian flatsedge.
A long-term, sustainable solution to weed infestation is extremely desirable because weeds have the potential to reduce crop productivity and the aesthetic appeal of the environment. In this study, ...the impacts of mowing and varying degrees of trampling pressure on the suppression of weeds, alongside wound-induced changes in the allelopathic potential, of the rhizosphere soil and the root exudates of southern crabgrass (Digitaria ciliaris) and Asian flatsedge (Cyperus microiria) were evaluated under both field and greenhouse conditions. The field study results showed that all trampling treatments induced the relative suppression of weed growth. Grass weeds showed higher resistance to trampling than broad-leaved weeds. However, laboratory bioassays showed that light trampling caused a significant increase in the growth-inhibitory effects of southern crabgrass rhizosphere soil on lettuce. Moreover, mowing (9.11% of control) and trampling (16.4% of control) resulted in a marginal increase in the growth-inhibitory effects of root exudates released from southern crabgrass. Furthermore, the growth-inhibitory activities of the Asian flatsedge rhizosphere soil were significantly reduced after heavy trampling pressure. Moreover, mowing and trampling resulted in marginal reductions in the growth-inhibitory activities of root exudates released from Asian flatsedge against lettuce (i.e., 18.7% and 28.5%, respectively). In general, mowing and varying degrees of trampling induced contrasting and integrated impacts on weed suppression as well as the allelopathic potential of both southern crabgrass and Asian flatsedge.
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