The present study is to understand the impact of process conditions on the quality attributes of wheat oat, barley, and canola straw briquettes. Analysis of variance indicated that briquette moisture content and initial density immediately after compaction and final density after 2 weeks of storage are strong functions of feedstock moisture content and compression pressure, whereas durability rating is influenced by die temperature and feedstock moisture content. Briquettes produced at a low feedstock moisture content of 9 % (w.b.) yielded maximum densities >700 kg/m 3 for wheat, oat, canola, and barley straws. Lower feedstock moisture content of <10 % (w.b.) and higher die temperatures >110°C and compression pressure >10 MPa minimized the briquette moisture content and maximized densities and durability rating based on surface plots observations. Optimal process conditions indicated that a low feedstock moisture content of about 9 % (w.b.), high die temperature of 120-130°C, medium-to-large hammer mill screen sizes of about 24 to 31.75 mm, and low to high compression pressures of 7.5 to 12.5 MPa minimized briquette moisture content to <8 % (w.b.) and maximized density to >700 kg/m 3 . Durability rating >90 % is achievable at higher die temperatures of >123°C, lower to medium feedstock moisture contents of 9 to 12 % (w.b.), low to high compression pressures of 7.5 to 12.5 MPa, and large hammer mill screen size of 31.75 mm, except for canola where a lower compression pressure of 7.5 to 8.5 MPa and a smaller hammer mill screen size of 19 mm for oat maximized the durability rating values.
This study investigated the relationship between vegetation coverage, species richness, and environmental factors, and also analyzed the relationship between vegetation coverage, species richness, and dune stability in different terrains, in the southern part of Gurbantu¨nggu¨t Desert in China. The results showed that the order of vegetation coverage and species richness was greatest in middle areas, followed by the eastern areas, with the western areas being sparse. On a large scale, precipitation from April to June determined the amount of vegetation coverage. On a small scale, vegetation coverage was influenced by the type of terrain and the water and salt content in soils. Species richness of vegetation was determined by soil water and salt content on both the large and small scales. There were also remarkable differences in relative wind erosion among the different terrains and their order was: crest, slope, and inter-dune in descending order. The correlations between wind erosion and vegetation coverage and species richness were influenced by the type of terrain. Furthermore, there were significant correlations between wind erosion and vegetation coverage and species richness in dune slopes and crests. There was, however, no significant correlation between wind erosion and vegetation coverage and species richness in inter-dune sites. Vegetation coverage was the dominant factor influencing wind erosion in both slopes and crests. Species richness may have an impact on wind erosion through vegetation coverage in both slopes and crests. These results suggest that the effect of terrain type should be fully considered during the establishment of vegetation cover in the desert.
Hierarchical porous carbon spheres (PCSs) with a tunable pore structure were prepared from larch sawdust via spray pyrolysis and a soft-templating method. Decomposition of the soft template, i.e., Pluronic F127, in the carbonization step led to formation of a hierarchical porous structure with mesopores and macropores. Swelling of the core, presumably predominantly of the poly(propylene oxide) component, was induced by evaporation of water. This led to the generation of ultra-large mesopores and macropores. The surface morphology and pore structure of the carbon spheres were controlled by varying the F127 concentration. The PCSs morphologies changed from smooth to rough with increasing addition of F127, and the particle sizes became more uniform. When the content of F127 reached 0.075 (ratio of F127/ larch-based resin), the prepared PCSs (PCSs-0.075) had structural integrity, a high surface area (760.3 m 2 g −1 ), and a large pore volume (0.59 cm 3 g −1 ), and contained a combination of micropores, macropores, and mesopores. X-ray diffraction and Raman spectroscopy showed that addition of F127 had little effect on the graphitic degree of the samples. Because of its hierarchical pore structure and high surface area, the optimized sample, i.e., PCSs-0.075, gave an excellent electrochemical performance as an electrode material for supercapacitors, with a specific capacitance of 338.8 F g −1 at 0.2 A g −1 and a good rate capability (165.1 F g −1 at 5 A g −1 ) in 6 M KOH solution. These PCSs with mesopores and macropores, which facilitate penetration of ions into pores, are promising as efficient electrode materials for supercapacitors.
Pressed condensation is a key process before the reclamation of loose corn straws. In this study, the effects of stabilization time on the relaxation density and dimensional stability of corn straws were studied firstly, and then the stabilization time was determined to be 60 s by comprehensively considering the compression effect, energy consumption, efficiency and significance. On this basis, the effects of the water content (12%, 15%, 18%), ratio of pressure maintenance time to stabilization time (0, 0.5, 1), maximum compression stress (60.4, 120.8, 181.2 kPa) and feeding mass (2.5, 3, 3.5 kg) on the relaxation density, dimensional stability coefficient, and specific energy consumption of post-compression straw blocks were investigated by the Box–Behnken design. It was found that the water content, ratio of pressure maintenance time to stabilization time, maximum compression stress, and feeding mass all very significantly affected the relaxation density, dimensional stability coefficient and specific energy consumption. The interaction between water content and maximum compression stress significantly affected both relaxation density and specific energy consumption. The interaction between the ratio of pressure maintenance time to stabilization time and feeding mass significantly affected the dimensional stability coefficient. The factors and the indices were regressed by quadratic equations, with the coefficients of determination larger than 0.97 in all equations. The optimized process parameters were water content of 13.63%, pressure maintenance time of 22.8 s, strain maintenance time of 37.2 s, maximum compression stress of 109.58 kPa, and raw material feeding mass of 3.5 kg. Under these conditions, the relaxation density of cold-pressed straw blocks was 145.63 kg/m3, the dimensional stability coefficient was 86.89%, and specific energy consumption was 245.78 J/kg. The errors between test results and predicted results were less than 2%. The low calorific value of cold-pressed chopped corn straw blocks was 12.8 MJ/kg. Through the situational analysis method based on the internal and external competition environments and competition conditions (SWOT analysis method), the cold-pressed chopped corn straw blocks consumed the lowest forming energy consumption than other forming methods and, thus, are feasible for heating by farmers. Our findings may provide a reference for corn straw bundling, cold-press forming processes and straw bale re-compressing.
Large amount of water are required for petroleum refinery activity and consequently produced larger volumes of effluents. Wastewater treatment is an important process before discharge these water into drainage system. In this work, several advanced electrochemical petroleum refinery effluents treatment approaches including direct electrochemical oxidation, indirect electrochemical oxidation, electrophenton process and electrocoagulation, were studied by using different electrode materials. Phenol and COD removal were used for estimated the performance of each method. Study showed almost all method could be effectively used for petroleum refinery effluents treatment except the electrocoagulation.
An expert seller chooses an experiment to influence a client's purchasing decision, but may manipulate the experiment result for personal gain. When credibility surpasses a critical threshold, the expert chooses a fully-revealing experiment and, if possible, manipulates the unfavorable result. In this case, a higher credibility strictly benefits the expert, whereas the client never benefits from the expert's services. We also discuss policies regarding monitoring expert's disclosure and price regulation. When prices are imposed exogenously, monitoring disclosure does not affect the client's highest equilibrium value. A lower price may harm the client when it discourages the expert from disclosing information.
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