As one of the oldest creatures on the earth, the tortoises have formed a nearly perfect shell structure after millions of years of evolution In this paper, Chinese tortoise shell is studied. Firstly, the scanni...As one of the oldest creatures on the earth, the tortoises have formed a nearly perfect shell structure after millions of years of evolution In this paper, Chinese tortoise shell is studied. Firstly, the scanning model of the tortoise shell is established by means of computer tomography （CT） scanning technology and MIMICS software. Secondly, the solid model of three-dimensional structure of the tortoise shell is constructed by using geomagic studio reverse engineering software. Afterwards, the compression numerical simulation of the tortoise shell structure under low strain rate is conducted with the help of finite element software LS-DYNA. Finally, load-bearing characteristics of the tortoise shell structure and dome-shaped structure are compared and analyzed. The results show that compared withthe dome-shaped structure with the same volume, tortoise shell structure has a higher structural rigidity and can withstand higher pressure. Therefore, tortoise shell structure provide some reference to the design of armored vehicles, sheltersand other types of thin shell structures.展开更多
It has been possible to pelletize wood Miscanthus mixtures （12.5%, 25% and 50%） without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has l...It has been possible to pelletize wood Miscanthus mixtures （12.5%, 25% and 50%） without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has led to unstable production, mainly explained by hammermill overfeeding. The unstable production has been identified as the main responsible factor of the low quality of pellets produced with pure Miscanthus for these trials. The produced pellets were tested in a 25 kW boiler and compared with agro-pellets of various origins： winter barley straw, rapeseed straw, reed, old hay, Miscanthus, and wood pellets. Results gained during these combustion trials allowed to describe combustion of these uncommon fuels and to characterize its emissions. The trials confirm general characteristics of agricultural fuel combustion： influence of the ash content on the gross calorific value, influence of the N content in the fuel on the NOx emissions, influence on the alkali content on the C12 emissions. But the influence of known parameter （S. alkali and earth alkali content） on SO2 emission might not be highlighted, while a relation with the fuel moisture content could be considered.展开更多
Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol ...Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.展开更多
文摘As one of the oldest creatures on the earth, the tortoises have formed a nearly perfect shell structure after millions of years of evolution In this paper, Chinese tortoise shell is studied. Firstly, the scanning model of the tortoise shell is established by means of computer tomography （CT） scanning technology and MIMICS software. Secondly, the solid model of three-dimensional structure of the tortoise shell is constructed by using geomagic studio reverse engineering software. Afterwards, the compression numerical simulation of the tortoise shell structure under low strain rate is conducted with the help of finite element software LS-DYNA. Finally, load-bearing characteristics of the tortoise shell structure and dome-shaped structure are compared and analyzed. The results show that compared withthe dome-shaped structure with the same volume, tortoise shell structure has a higher structural rigidity and can withstand higher pressure. Therefore, tortoise shell structure provide some reference to the design of armored vehicles, sheltersand other types of thin shell structures.
文摘It has been possible to pelletize wood Miscanthus mixtures （12.5%, 25% and 50%） without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has led to unstable production, mainly explained by hammermill overfeeding. The unstable production has been identified as the main responsible factor of the low quality of pellets produced with pure Miscanthus for these trials. The produced pellets were tested in a 25 kW boiler and compared with agro-pellets of various origins： winter barley straw, rapeseed straw, reed, old hay, Miscanthus, and wood pellets. Results gained during these combustion trials allowed to describe combustion of these uncommon fuels and to characterize its emissions. The trials confirm general characteristics of agricultural fuel combustion： influence of the ash content on the gross calorific value, influence of the N content in the fuel on the NOx emissions, influence on the alkali content on the C12 emissions. But the influence of known parameter （S. alkali and earth alkali content） on SO2 emission might not be highlighted, while a relation with the fuel moisture content could be considered.
文摘Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.
