Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally i...Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally in practice and may not equal soil suction. The influences of suction and root moisture contents were investigated on Chrysopogon zizanioides(vetiver grass) root tensile strength. The root specimens were equilibrated with moist air in different suction conditions(0, 10, 20, and 50 kPa), prior to root tension tests. The root-water characteristic curve or relationship between root moisture and suction, was determined. The increase in suction resulted in decreased tensile strengths of the grass roots, particularly those with diameter of about 0.2 mm, which constituted 50.7% of all roots. For 1 mm roots, the tensile strength appeared to be unaffected by suction increase. The average root tensile strengths were used to estimate the root cohesion in slope stability analysis to find variation of safety factors of a bioengineered slope in different suction conditions. The analysis showed that the critical condition of slope with the lowest factor of safety would happen when the soil suction was zero and the root suction was high. Such condition may occur during a heavy rain period after a prolonged drought.展开更多
The purpose of this study is to select an appropriate commercial neutral cellulase enzyme for denim garments bio-polishing to achieve specific industrial goals. A full factorial experimental design was used to evaluat...The purpose of this study is to select an appropriate commercial neutral cellulase enzyme for denim garments bio-polishing to achieve specific industrial goals. A full factorial experimental design was used to evaluate the effect of factors considered in the optimization of the bio-polishing process (fabric ID: x1, treatment time: x2, treatment temperature: x3, enzyme concentration: x4, storage time: x5, inactivation step: x6 and enzyme type: x7). Experiments were conducted using laboratory washing machine. Subjective evaluation was performed at a pilot and at an industrial scale. Tear, tensile strength and subjective evaluation concerning hand feel, fabric color, indigo dye pocket back staining and fuzziness extent were evaluated. Results showed that x6 and x7 had significant effects on the fabric tear and tensile strength loss. In the optimization, the great dependence between observed and predicted tear strength and tensile strength loss, the correlation coefficient of the models (R<sup>2</sup> > 0.85) and the important value of F-ratio proved the validity of the models. Results showed that denim leg panels treated with the enzyme Lava-Cell NSZ presented a minimum loss of tear and tensile strength. A low-temperature and time enzymatic bio-polishing process was developed at industrial scale.展开更多
Bio-embankment is an important soil and water conservation measure in the purple hilly area in China,which can effectively improve the ability of cultivated soil layers to resist rainfall erosion and runoff scour.In c...Bio-embankment is an important soil and water conservation measure in the purple hilly area in China,which can effectively improve the ability of cultivated soil layers to resist rainfall erosion and runoff scour.In contrast,the ecological effect of bioembankment depends on the stability of the earth bank.Taking the natural grass bank as a control(CK),the root distribution,root tensile properties and shear resistance of root-soil composites for 3 typical soil and water conservation bio-embankments,namely,Morus alba Linn(Morns),Zanthoxylum bungeanum Maxim(Zanthoxylum)and Medicago sativa(Medicago)were analysed.The results included the following:(1)The root system of the bio-embankments generally decreased in extent with the soil depth;fine roots in the o-io cm depth were most prevalent and significantly higher than those at the other depths,and coarse roots were mainly distributed in the o-30cm layer.(2)The stress-strain curves of the roots of each bio-embankment were single-peak curves without clear strain softening phenomena.The smaller the root diameters were,the smoother the stress-strain curves,and the lower the capability of the earth bank to resist collapse.The larger the root diameters were,the lower the tensile strength.The average root tensile force was highest for Zanthoxylum(73.91 N),followed by Medicago(68.07N)and Morus(61.88 N),and the average root tensile strength showed the same trend,16.52 MPa for Zanthoxylum,16.08 MPa for Medicago and 13.02MPa for Morus.(3)The bio-embankment measures significantly improved the soil shear resistance,especially under vertical loads of 1oo kPa and 200kPa.The soil internal friction angle showed a significant log-positive correlation with root morphological parameters of root length density(RLD),root surface area density(RSAD) and rootweight density(RWD),while the soil cohesion force showed a positive linear correlation with these parameters.The results provide effective parameters supporting for the design of bio-embankments and promoting the use of soil reinforcement with suitable species selection in protective earth banks for stability in the purple hilly area.展开更多
Bacillus subtilis was selected as the suitable microorganism,which could produce alkaline phosphatase and constantly hydrolyzed phosphate monoester in the mixture solution of bacteria with substrate,and then the PO4^3...Bacillus subtilis was selected as the suitable microorganism,which could produce alkaline phosphatase and constantly hydrolyzed phosphate monoester in the mixture solution of bacteria with substrate,and then the PO4^3-was obtained.Bio-phosphate cement was prepared by alkaline earth element（Ba）ions reacting with PO4^3-in the mixture solution.Structure,size and thermal properties of the bio-phosphate cement were characterized by energy dispersive X-ray spectroscopy（EDS）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and particle size analysis.The average crystallite sizes of chem-BaHPO4 and bio-BaHPO4corresponded to 11.99 and 24.13μm,respectively.Chem-BaHPO4 and bio-BaHPO4 were then adopted to bind loose sand particles.The results indicated that loose sand particles can be well cemented by the bio-BaHPO4powder into a bio-sandstone with a certain mechanical properties,and the average compressive strength of the bio-sandstones can be up to 0.83 MPa when the curing time was 14 d.Along with the method in future studies,there will be multiple new opportunities for engineering applications,for instance,the treatment of sandy soil foundation,remediation of heavy metals in contaminated soil,and so on.展开更多
CaO-loaded solid base used in transesterification of rape oil was prepared by loading CaO on MgO. The base strength and content of the solid base at different preparation conditions were analyzed. The solid base belon...CaO-loaded solid base used in transesterification of rape oil was prepared by loading CaO on MgO. The base strength and content of the solid base at different preparation conditions were analyzed. The solid base belonged to superbase with the base strength of 27.0 < H- < 37.0. After dipped in 22.4% Ca(AC)2 for 1h and calcined at 700℃ for 24h, highest basic content of the solid base were achieved (H- >9.3, 25.68 mmol/g). The solid base exhibited high catalytic activity in transesterification of rape oil into bio-diesel, and the rape oil conversion reached 97.95%.展开更多
基金the financial supports from the Chaipattana FoundationKasetsart University Research and Development Institute(KURDI)the scholarship for his PhD studies provided by the Faculty of Engineering,Kasetsart University
文摘Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally in practice and may not equal soil suction. The influences of suction and root moisture contents were investigated on Chrysopogon zizanioides(vetiver grass) root tensile strength. The root specimens were equilibrated with moist air in different suction conditions(0, 10, 20, and 50 kPa), prior to root tension tests. The root-water characteristic curve or relationship between root moisture and suction, was determined. The increase in suction resulted in decreased tensile strengths of the grass roots, particularly those with diameter of about 0.2 mm, which constituted 50.7% of all roots. For 1 mm roots, the tensile strength appeared to be unaffected by suction increase. The average root tensile strengths were used to estimate the root cohesion in slope stability analysis to find variation of safety factors of a bioengineered slope in different suction conditions. The analysis showed that the critical condition of slope with the lowest factor of safety would happen when the soil suction was zero and the root suction was high. Such condition may occur during a heavy rain period after a prolonged drought.
文摘The purpose of this study is to select an appropriate commercial neutral cellulase enzyme for denim garments bio-polishing to achieve specific industrial goals. A full factorial experimental design was used to evaluate the effect of factors considered in the optimization of the bio-polishing process (fabric ID: x1, treatment time: x2, treatment temperature: x3, enzyme concentration: x4, storage time: x5, inactivation step: x6 and enzyme type: x7). Experiments were conducted using laboratory washing machine. Subjective evaluation was performed at a pilot and at an industrial scale. Tear, tensile strength and subjective evaluation concerning hand feel, fabric color, indigo dye pocket back staining and fuzziness extent were evaluated. Results showed that x6 and x7 had significant effects on the fabric tear and tensile strength loss. In the optimization, the great dependence between observed and predicted tear strength and tensile strength loss, the correlation coefficient of the models (R<sup>2</sup> > 0.85) and the important value of F-ratio proved the validity of the models. Results showed that denim leg panels treated with the enzyme Lava-Cell NSZ presented a minimum loss of tear and tensile strength. A low-temperature and time enzymatic bio-polishing process was developed at industrial scale.
基金funded by the Natural Science Foundation of China (Grants No. 41771310)the Public welfare industry (agriculture) special research project (Grants No. 201503119-01-01).
文摘Bio-embankment is an important soil and water conservation measure in the purple hilly area in China,which can effectively improve the ability of cultivated soil layers to resist rainfall erosion and runoff scour.In contrast,the ecological effect of bioembankment depends on the stability of the earth bank.Taking the natural grass bank as a control(CK),the root distribution,root tensile properties and shear resistance of root-soil composites for 3 typical soil and water conservation bio-embankments,namely,Morus alba Linn(Morns),Zanthoxylum bungeanum Maxim(Zanthoxylum)and Medicago sativa(Medicago)were analysed.The results included the following:(1)The root system of the bio-embankments generally decreased in extent with the soil depth;fine roots in the o-io cm depth were most prevalent and significantly higher than those at the other depths,and coarse roots were mainly distributed in the o-30cm layer.(2)The stress-strain curves of the roots of each bio-embankment were single-peak curves without clear strain softening phenomena.The smaller the root diameters were,the smoother the stress-strain curves,and the lower the capability of the earth bank to resist collapse.The larger the root diameters were,the lower the tensile strength.The average root tensile force was highest for Zanthoxylum(73.91 N),followed by Medicago(68.07N)and Morus(61.88 N),and the average root tensile strength showed the same trend,16.52 MPa for Zanthoxylum,16.08 MPa for Medicago and 13.02MPa for Morus.(3)The bio-embankment measures significantly improved the soil shear resistance,especially under vertical loads of 1oo kPa and 200kPa.The soil internal friction angle showed a significant log-positive correlation with root morphological parameters of root length density(RLD),root surface area density(RSAD) and rootweight density(RWD),while the soil cohesion force showed a positive linear correlation with these parameters.The results provide effective parameters supporting for the design of bio-embankments and promoting the use of soil reinforcement with suitable species selection in protective earth banks for stability in the purple hilly area.
基金Funded by the National Natural Science Foundation of China(No.51702238)
文摘Bacillus subtilis was selected as the suitable microorganism,which could produce alkaline phosphatase and constantly hydrolyzed phosphate monoester in the mixture solution of bacteria with substrate,and then the PO4^3-was obtained.Bio-phosphate cement was prepared by alkaline earth element（Ba）ions reacting with PO4^3-in the mixture solution.Structure,size and thermal properties of the bio-phosphate cement were characterized by energy dispersive X-ray spectroscopy（EDS）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and particle size analysis.The average crystallite sizes of chem-BaHPO4 and bio-BaHPO4corresponded to 11.99 and 24.13μm,respectively.Chem-BaHPO4 and bio-BaHPO4 were then adopted to bind loose sand particles.The results indicated that loose sand particles can be well cemented by the bio-BaHPO4powder into a bio-sandstone with a certain mechanical properties,and the average compressive strength of the bio-sandstones can be up to 0.83 MPa when the curing time was 14 d.Along with the method in future studies,there will be multiple new opportunities for engineering applications,for instance,the treatment of sandy soil foundation,remediation of heavy metals in contaminated soil,and so on.
文摘CaO-loaded solid base used in transesterification of rape oil was prepared by loading CaO on MgO. The base strength and content of the solid base at different preparation conditions were analyzed. The solid base belonged to superbase with the base strength of 27.0 < H- < 37.0. After dipped in 22.4% Ca(AC)2 for 1h and calcined at 700℃ for 24h, highest basic content of the solid base were achieved (H- >9.3, 25.68 mmol/g). The solid base exhibited high catalytic activity in transesterification of rape oil into bio-diesel, and the rape oil conversion reached 97.95%.
