Non-host resistance (NHR) confers plant species immunity against the majority of microbes. As an important crop, wheat can be damaged by several Puccinia species but is immune to all Uromyces ...species. Here, we studied the basis of NHR in wheat against the broad bean rust pathogen Uromyces fabae (Uf). In the wheat—Uf interaction, microscopic observations showed that urediospores germinated efficiently on wheat leaves. However, over 98% of the germ tubes failed to form appressoria over stomata. For the few that invaded through stomata, the majority of them failed to penetrate wheat mesophyll cells. At 96 hours after inoculation, less than 4% of the Uf infection units that had entered the mesophyll tissue formed haustoria. Attempted penetration by haustorium mother cells induced the thickening of cell wall and the formation of papillae in plant cells, which arrested the development or growth of Uf penetration pegs. For the Uf haustoria formed in wheat cells, they were encased in callose-like materials and did not elicit hypersensitive response. Localized accumulation of H2O2 were observed in plant cell walls, papillae and encasement of haustoria during the wheat—Uf interaction. Furthermore, quantitative RT-PCR analysis showed that several genes involved in basal resistance and oxidative stress responses were up-regulated during Uf infection. In conclusion, our study revealed the cytological and molecular bases of NHR in wheat against the non-adapted rust fungus Uf, and highlighted the significance of papilla production in the prehaustorial NHR.
In this study, a thermodynamic model of a hybrid system consisting of a proton-exchange membrane fuel cell (PEMFC) system and an organic Rankine cycle (ORC) system is established using Aspen Plus ...software. The optimal working fluid is selected by comparing the performance of pure working fluids and zeotropic mixtures of working fluids in an ORC system. The zeotropic working fluid consisting of R245fa/R123 with a mixing ratio of 0.6/0.4 shows the best performance. The effects of some key parameters, including the current density and operating temperature, on the performance of the PEMFC–ORC system with zeotropic mixing fluids are discussed. The results indicate that the power and efficiency of the PEMFC–ORC system with the zeotropic mixing fluid increase with increasing operating temperature. When the R245fa/R123 zeotropic working fluid with a mixing ratio of 0.6/0.4 is used, the net power and efficiency of the hybrid system reach optimum values under the studied boundaries, with improvements of 12.87% and 4.84%, respectively. The influence of the maximum allowable evaporation pressure and stack operating temperature on the selection of optimum working fluid for the hybrid system is discussed in addition.
•Using ORC as cooling system improves the PEM thermal efficiency.•Zeotropic fluid shows significant improvement of hydrogen fuel cell performance.•Power of ORC and PEMFC–ORC system increases as current density increases.•Working fluids have different optimal evaporation pressure and temperature.
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•Soot reactivity of diesel engine fueled with methanol-diesel blends was investigated.•Methanol addition leads to a higher oxidative reactivity of diesel soot.•Effects of methanol ...addition on soot structure and chemistry were assessed.•Methanol blend yields soot with less compactness and more disordered structure.•Methanol addition increases content of aliphatic C-H groups on diesel-soot surface.
This paper compared the soot reactivity and its primarily related factors including soot structure, graphitization degree and surface functional groups, when using mineral diesel fuel (DF) and methanol blended fuel (MBF) at two typical low and high engine loads. Results showed that the soot reactivity increases with increasing methanol concentration in the MBF. Additionally, with the constant methanol blend ratio of methanol, the reactivity of MBF soot degrades as the engine load increases. Correspondingly, the MBF soots had lower aggregate compactness, smaller primary particle size, more disordered structure and more active aliphatic C-H groups in comparison with the DF soot, providing higher concentration and accessibility of active sites for oxidation reactions. The addition of methanol creates variations in combustion kinetics and fuel formulation, which exerts reverse effects on the soot structure and chemistry. Therefore, the factors related to these properties show non-monotonic variations when alter the methanol blend ratio and engine operating mode. Especially, when the methanol blend ratio increases from 10% to 15%, the soot structure and chemistry transform onto the features that are reluctant for soot oxidation.
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•Engine load affects diesel soot restructuring in atmosphere.•The high-load soot decreases and then increases in primary particle diameter during restructuring.•The change in radius ...of gyration is more noticeable with the high-load soot during restructuring.•The boundary irregularities of soot diminishes during restructuring, especially the low-load soot.
This paper investigates the restructuring of soot particles from a diesel engine (operated at low and high (30% and 90%) loads of 1200 rpm) exhaust gas discharged into a simulated atmospheric environment. The morphological characteristics of soot particles during the aging times of 0 min, 30 min, 60 min, 120 min, and 180 min were observed by transmission electron microscopy (TEM) to analyze the changes of primary particle diameter (dp), the radius of gyration (Rg), aggregation parameters (aspect ratio, roundness, and root form factor) and fractal dimension (Df) of soot. The results indicate that the dp of the low-load soot tends to increase in the 0–30 min aging period and then it behaves smoothly till to 180 min, while the dp of the high-load soot tends to decrease and then increase, with the minimum value of dp occurring at 60 min of aging. In terms of Rg, the low-load soot appears to age more quickly than the high-load soot, owing to the shorter branch chains for the low-load soot than that for the high-load soot. The trends in the aspect ratio (AR), roundness (RN), and root form factor (RFF), of soot during aging indicate that soot is developing towards a more compact aggregation, especially for the low-load soot. In addition, the Df value tends to increase during the aging process for the low- and high-load soot, but compared to the high-load soot, the low-load soot shows a higher aging degree and faster aging speed during the aging process.
•Nanoparticle (NP) addition improves methanol-diesel fuel (MDF) ignition at <30% load.•Alumina and ceria nanoparticles cause stronger ignition improvement of MDF than silica.•NP addition in MDF ...increases peak cylinder pressure by ≤4.6% in 100 ppm dosage.•NP addition exerts negatively effects on reduction of CO, HC and smoke emissions for MDF.•Alumina and ceria nanoparticle cause higher NOx deterioration degrees than silica.
Methanol is widely used as a potential alternative source for diesel fuel and can reduce the CO, THC and smoke emissions of the CI engines. However, the lower cetane number and energy content of methanol hinder the high substitution of methanol over diesel fuel. Introducing nanoparticles as fuel-additive is an effective approach to cope with this issue. In the present work, the alumina, ceria and silica nanoparticles were separately mixed into methanol in mass proportions of 25, 50 and 100 ppm with the composite surfactant of sodium dodecyl benzene sulfonate and cetyl trimethyl ammonium bromide (1:1 mass fraction) to create the nanofluid. The nanofluid was then injected into the intake port to combust synergistically with the mineral diesel fuel injected by the other high-pressure injection system, generating the nanoparticle-assisted methanol-diesel fuel mode (NMF). The characteristics of combustion and pollutant emission of NMFs were investigated with 10%, 30% and 50% methanol substituted level (M10, M30 and M50, respectively), at 10–90% engine loads of a constant engine speed. The results showed that the substitution of methanol led to an extension in the ignition delay but a shortening of combustion duration than diesel fuel. The additional introduction of alumina and ceria nanoparticles in each dosage, and silica nanoparticles in 100 ppm dosage, into M10 slightly shortened the ignition delay at 10% load conditions. When dosed into M50 fuel, all the three nanoparticles in various dosages led to shortened ignition delay at 10–50% engine loads. Over the test conditions, the addition of nanoparticles all caused a distinct increase in the peak in-cylinder pressure for the methanol-diesel dual-fuel mode. However, the addition of nanoparticles exerted marginal influences on further reduction of CO, HC and smoke emissions, and even further elevated the NOx emissions for MDF mode by up to 40%. Moreover, the deterioration degrees of NOx emissions for alumina and ceria nanoparticle addition were higher than the silica nanoparticles, and elevated towards the higher nanoparticle dosage and lower engine load.
•Proposed a 1 MW off–grid photovoltaic hydrogen production system;•Auxiliary system powered by organic Rankine cycle with evacuated tube collectors;•Annual hydrogen production is 27.15 tons;•The ...photovoltaic plant retrofit project payback period is 12 years.
Water electrolysis technology is a potential approach for green hydrogen production and photovoltaic power consumption. However, due to the volatility and uncertainty of the solar energy, supplying photovoltaic power directly to the water electrolysis auxiliary system is instable. An innovative off–grid photovoltaic proton exchange membrane electrolytic cells hydrogen production system is proposed to address that issue. The system integrates an organic Rankine cycle system with evacuated tube collector modules to supply power for the auxiliary system. The electrical power generated by the photovoltaic module is directly supplied to the proton exchange membrane electrolytic cells. The matching of the organic Rankine cycle system output power and auxiliary system power demand has been conducted by comparing the temperature control methods and parameters. The thermodynamic and economic performances of the photovoltaic hydrogen production system have been investigated with the meteorological data of Nanjing. The results demonstrate the organic Rankine cycle system can completely satisfy the power demand of the auxiliary system operation. The annual hydrogen production of the system can reach 26.07 tons (316203.0 Nm3) and the hydrogen average electricity consumption is 4.75 kWh/Nm3. The system has a maximum energy and exergy efficiency of 8.8 % and 9.1 %, respectively. This system is suitable for retrofitting photovoltaic plants, the payback period of the retrofit project is 12 years, which shows higher profitability than that of grid-supplied hydrogen production.
•Ammonia storage characteristics on a Cu-based zeolite SCR catalyst were investigated experimentally.•The maximum ammonia storage decreases with the increase of exhaust temperature over 220 ℃.•The ...most extended duration of the ammonia storage process occurred at 220 ℃.•The maximum NOx conversion efficiency attains 80% at 180 ℃ and 100% at 220 ℃ or above.•The ammonia storage and the exhaust temperature are the main factors in NOx conversion performance in SCR catalysts.
The ammonia storage characteristics were studied experimentally in two stages before and after shutting off the urea injection on a full-size Cu-based zeolite SCR catalyst. The experiment was conducted under the engine operating conditions with exhaust temperatures of 180, 220, 260, 300, 340, and 380 ℃. The variations of the ammonia storage amount, NOx conversion efficiency, and ammonia slip were separately investigated within the period of ammonia storage and consumption process. The results indicate that the maximum ammonia storage is only 10 g at 180 ℃, but around 43 g at 220 ℃. The maximum ammonia storage decreases with the increase of exhaust temperature over 220 ℃, which drops from 35 g at 260 ℃ down to below 13 g at 380 ℃. The most extended duration of 8082 s on the ammonia storage process occurred at the exhaust temperature of 220 ℃, mainly due to the deposit formation. The time width of the ammonia storage process is shortened with the exhaust temperature increasing over 220 ℃. The maximum NOx conversion efficiency is 80% at the temperature of 180 ℃ and 100% when the temperature rises to 220 ℃ or above. The higher temperature can improve the catalyst activity to supply more activated ammonia reacting with NOx. However, it promotes further ammonia slip. The ammonia storage and exhaust temperature are the main factors in the NOx conversion performance in the SCR catalyst. When the temperature is below 220 ℃, the NOx conversion efficiency strongly depends on the ammonia storage and increases with its amount. With the temperature further rising to 220℃ and above, the impact of the exhaust temperature on NOx conversion efficiency gradually increases.
•Systematic study of the rising motion of oil droplets in natural waters.•Discovered that oil droplet properties affect the rising motion process.•Modeling the terminal velocity of oil droplets in ...natural waters.•Modeling the drag coefficient of oil droplets in natural waters.
This work focuses on investigating the dynamics of different types of oil droplets rising freely in water columns. Fifteen different types of oils were selected to cover most of the conventional oils. The particle size range of the study is 1.41∼13.58 mm, which can cover the largest oil droplet size that may occur in the real environment. Investigation results show that oil droplet characteristics greatly influence the dynamics process of oil droplet motion. The characteristics which play a dominant role will change as the oil droplet particle size increases. Meanwhile, a set of computational models applicable to the terminal velocity and drag coefficient of oil droplets in the range of 20 < Re < 1200 in a non-pure system are obtained by organizing the experimental data and comparing with the traditional correlation equation, respectively. The models involve dimensionless parameters such as Eo, Mo, and We numbers with fitting coefficients up to 0.984.
•Nano-Al2O3 addition increases HRRmax and CGPmax, especially at high engine load.•Al2O3 nanoparticles causes obvious ignition and combustion duration improvements.•Nano-Al2O3 nanoparticles results in ...the reduction of CO, HC and smoke emissions.•Nano-Al2O3 addition in methanol/diesel blend brings the most appear increment in NOX emission.
The study investigates the effects of the primary alcohol (methanol, ethanol, n-butanol) and aluminum (Al2O3) nano-additive on combustion and emission characteristics of a direct injection diesel engine at 30% (low) and 80% (high) engine loads of a constant engine speed. The alcohol/diesel nanofuels were made by adding Al2O3 nanoparticles (25, 100 ppm) into the alcohol/diesel blend (the same oxygen content level) with ultrasonic mixing and surfactant assistance. The results revealed that an extension in the ignition delay was induced by the substitution of primary alcohol fuel, among which methanol showed the most apparent regardless of engine load. Under high load, the addition of methanol in diesel aroused the most obvious promotion effects on peak heat release rate (HRRmax) and peak cylinder gas pressure (CGPmax), while under low load, the addition of n-butanol had the most obvious promotion effect. The addition of Al2O3 nanoparticles to the alcohol/diesel blend significantly improved the combustion process, with the results of decreased ignition delay, increased CGPmax and HRRmax, and shortened combustion duration, especially for the cases in high nanoparticles dosage (with a few exceptions). Under both loading conditions, the addition of methanol led to the least emissions of CO, NOX, and smoke opacity among the three alcohol fuels, while HC emissions presented just the opposite trends. Compared to pure diesel fuel, the engine powered by alcohol/diesel nanofuels emitted less CO, HC, and smoke emissions with a reduction amplitude of 36.2–77.8%, −8.8–10.7%, and 24.2–55.6%, respectively. However, Al2O3 nanoparticles addition brought more NOX emission with the increment of 6.2–17.5%, especially for the methanol/diesel nanofuels.
The seawater immersion test is an important indicator of the lithium ion batteries (LIBs) safety, and the fire behavior of LIBs is affected by immersion time tim. In this study, 3.5 wt% NaCl solution ...as surrogate seawater is used to perform LIBs immersion test. Several parameters are measured to evaluate the fire hazards of LIBs, such as ignition time tig, surface temperature, mass loss, heat release rate and total heat release. The fire hazards of batteries immersed under different tim is assessed by a conical calorimeter. The experimental results demonstrate that tig reaches a minimum value when tim is 3 h, and tig changes slightly with further increase of tim. The heat release rate reaches a maximum value when tim is 3 h for 100% stages of charge (SOC), and 2 h for 50% SOC. The ejection temperature Tej remains constant with the increase in tim, while the maximum temperature Tmax decreases with the increase in tim.
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•The burning behaviors of 18650 LIBs after different immersion times are investigated.•The safety valve can be damaged by the salt water after a long time immersion.•The battery ignition time is influenced seriously with the increase of the immersion time.•The total mass loss decreases with the increase in the immersion time.•There are peak values for total heat release and heat release rate with the immersion time of 3 h for 100% SOC.
