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Laminated ZrB2–SiC ceramics with graphite and BN as the interface layers were fabricated by tape casting and consequent hot pressing. The influences of interface materials on the thermal shock resistance of the laminated ceramics were studied by both experimental and theoretical analyses. Experimental results show that the critical temperature differences of G/LZS (laminated ZrB2–SiC/G) and BN/LZS (laminated ZrB2–SiC/BN) were 237 and 99 °C, respectively. The stress gradients of G/LZS and BN/LZS calculated via finite element analysis were 709 and 809 MPa/mm, respectively. Thus, the thermal shock resistance of G/LZS was higher than that of BN/LZS. Such merits of G/LZS can be explained by the following two reasons: one is the thermal conductivity of the graphite interface layer was higher than that of the BN interface layer; the other is the difference of the thermal expansion coefficient for the graphite interface layer and the matrix layer was lower than that for the BN interface layer and the matrix layer.

In order to study the dehydrogenation reaction mechanism of ultra-low concentration methane in a thermal reverse-flow reactor, the effects of the cyclic period (120s–240s), the lean methane volume flow (90 Nm3/h to 180 Nm3/h), and the methane concentration (0.2 vol% to 0.8 vol%) on the dehydrogenation performance were studied systematically by using a thermal reverse-flow experimental system. When the methane concentration is 0.2 vol%, the reactor can achieve self-heat maintaining operation. With the increase in the methane concentration, the width of the high-temperature zone, the exhaust gas temperature, the methane conversion rate, and the maximum temperature of the heat-accumulator bed increase. With the increase in the lean methane volume flow, the width of the high-temperature zone, the distance between the center of the high-temperature zone and the center of the reactor, the maximum temperature, the exhaust gas temperature, and the methane conversion rate increase. With the increase in the cyclic period, the exhaust gas temperature and the deviation of the high-temperature zone increase, but the methane conversion rate and the maximum temperature decrease slightly.

Biomass and grain yield are key agronomic traits in sorghum (Sorghum bicolor); however, the molecular mechanisms that regulate these traits are not well understood. Here, we characterized the biomass yield 1 (by1) mutant, which displays a dramatically altered phenotype that includes reduced plant height, narrow stems, erect and narrow leaves, and abnormal floral organs. Histological analysis suggested that these phenotypic defects are mainly caused by inhibited cell elongation and abnormal floral organ development. Map-based cloning revealed that BY1 encodes a 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHPS) that catalyses the first step of the shikimate pathway. BY1 was localized in chloroplasts and was ubiquitously distributed in the organs examined, particularly in the roots, stems, leaves, and panicles, which was consistent with its role in biomass production and grain yield. Transcriptome analysis and metabolic profiling revealed that BY1 was involved in primary metabolism and that it affected the biosynthesis of various secondary metabolites, especially flavonoids. Taken together, these findings demonstrate that BY1 affects biomass and grain yield in sorghum by regulating primary and secondary metabolism via the shikimate pathway. Moreover, our results provide important insights into the relationship between plant development and metabolism.

A visible light responsive photocatalyst consisting Ag–AgCl composite dispersed over TiO 2 /palygorskite (Ag–AgCl–TiO 2 /palygorskite) was synthesized via a facile method. The as-obtained samples were characterized by X-ray diffraction (XRD), Raman spectra, nitrogen adsorption-desorption measurements, UV–visible diffused reflectance spectra (UV–vis DRS) and X-ray photoelectron spectroscopy (XPS). The results confirmed that the localized surface plasmon resonance of Ag nanoparticles in the Ag–AgCl–TiO 2 /palygorskite composite resulted in a plasmon resonance absorption band in the visible region. The photocatalytic activity of the composite was evaluated by degradation of Rhodamine B (RhB) and 4-nitrophenol (4-NP) under visible light irradiation. The results indicate that Ag–AgCl–TiO 2 /palygorskite catalyst exhibited stronger adsorption capacity and higher photocatalytic degradation efficiency for RhB dye than the well-known commercial P25 TiO 2 photocatalyst, the TiO 2 /palygorskite, the Ag–TiO 2 /palygorskite, the AgCl–TiO 2 /palygorskite and the Ag–AgCl composite. In addition, the photoactive radical species involved in the degradation reaction also have been investigated by quenching experiments.

The results of experimental investigations on catalytic oxidation of coal mine ventilation air methane in a preheat catalytic reaction reactor is presented in this paper. The experimental system was located in the Energy Research Institute of Shandong University of Technology, which has been applied to investigate the effects of startup conditions such as the startup flow coefficient (0.3–0.5) and the startup power (10 kW–20 kW) on the startup process within the preheat catalytic reaction reactor. The average temperature distribution of catalytic oxidation bed and the minimal startup power were measured and the effects of operating conditions such as the space velocity (2600 h−1 to 11,500 h−1) and the methane concentration (0.8%–1.2%) were experimentally investigated. Moreover, the methane conversion rate and the average temperature of the catalytic oxidation bed were discussed and the critical space velocity value and the critical methane concentration value were determined.

Inspired by detailed designs of industrial porous burners, the combustion of methane%air mixtures in a non-catalytic reverse-flow reactor was studied numerically. The governing equations are the unsteady state equations of conservation of mass and chemical species, with separate energy equations for the solid and gas phases. These equations were solved using the commercial CFD code Fluent. In order to reveal the actual thermal oxidation in porous media, the user defined function (UDF) is used to extend the ability of FLUENT. The model has been used to investigate the effects of operating conditions such as the mixture inlet approach velocity (0.15 to 0.8 m/s) and methane concentration (0.3 to 0.7%) on the oxidation of methane within non-catalytic reactors packed with ceramic monolith blocks under adiabatic conditions. The calculated values of methane conversion showed good agreement with the corresponding available experimental data. Moreover temperature distribution characteristics in the oxidation bed were studied in order to maintain the autothermicity of TFRR with a high enough temperature in the hot zone. Metan iz premogovnikov ni le toplogredni plin, neizkoriščen je tudi izgubljen vir energije. Zaradi zelo nizkih koncentracij CH4 se kot najobetavnejša rešitev kaže avtotermično zgorevanje v reaktorjih z izmenjevanjem smeri toka. Večina dosedanjih študij je bila posvečena katalitičnemu zgorevanju v katalitičnih reaktorjih z izmenjavanjem smeri toka (CFRR). Ekonomsko in tehnično najprimernejša rešitev za izkoriščanje toplotne energije pa so termični reaktorji z izmenjevanjem smeri toka (TFRR). Nekatalitična oksidacija v TFRR je zato pogosto privlačna alternativa. Tovrstni reaktorji so že dolgo v uporabi, npr. za homogeno kurjenje hlapnih organskih spojin (VOC). Med zgorevanjem VOC in oksidacijo metana iz prezračevalnih sistemov v reaktorjih z izmenjevanjem smeri toka obstajajo očitne razlike. Termično zgorevanje v TFRR mora potekati pri pogojih, ki ne sprožajo čezmernega nastajanja NOx, t.j. maksimalna temperatura v reaktorju je lahko največ 1300 °C. Uporaba TFRR za kurjenje revnih zmesi metana zato zahteva podrobno preučitev delovnih pogojev.

Results of simulation concerning a reverse flow reactor for thermal oxidation of lean methane are presented. The method termed outlet heat gas withdrawal is employed and analyzed. The method is direct withdrawal of heat from the outlet of the reactor. Simulations show that a relation exists between the outlet temperature of hot gas withdrawal and the methane concentration. The results reveal that outlet hot gas withdrawal guarantees symmetry of the semi-cycle temperature profiles of reverse flow and the cyclic steady state operation of the reactor can be easily obtained.

Thermal flow reversal reaction (TFRR) is a proper method to deal with lean methane. Heat recovery efficiency, peak temperature and switching time are key parameters of TFRR. Experiments were carried out to study these parameters. The results show that: the quality of heat energy loses in the process of heat transfer; the peak temperature could be controlled by changing of switching time; withdraw hot gas from the end of reactor is not proper for energy output.

A full dynamic one-dimensional model of a reverse flow reactor for thermal oxidation of lean methane and a code for its solution are employed. The simulation concerning starting up of the reverse flow reactor is carried out. An electric heater at the end of the reactor is employed during starting up of the reactor. The influence of heating operation of the heater and the hot region moving from the end to central part during starting up of the reactor has been investigated in detail. The results show that the initial temperature profiles on the central part of the reactor can be obtained in two steps.

Combustion of coal mine ventilation air methane (VAM) was investigated in a thermal reverse-flow reactor. Effects of CH 4 concentration, VAM flow and temperature were studied. The results show that combustion of coal mine ventilation air methane be achieved for methane concentration of 0.2%~0.8% in reactor. The conversion rates of CH 4 are all above 99%.Some heat could be recovered. With the increase of CH 4 concentration and VAM flow, the temperature of middle area increase, the volume of high temperature increase. It is to improve conversion rate of CH 4 . The lowest combustion temperature is 880degC.