The Experts below are selected from a list of 525 Experts worldwide ranked by ideXlab platform
Achim Stolle - One of the best experts on this subject based on the ideXlab platform.
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influence of reaction parameters on the depolymerization of h2so4 impregnated cellulose in planetary ball mills
Powder Technology, 2016Co-Authors: Robert Schmidt, Sindy Fuhrmann, Lothar Wondraczek, Achim StolleAbstract:Abstract The depolymerization of acid-impregnated cellulose in planetary ball mills was investigated under the perspective of the influence of reaction parameters. Several process, technological and chemical parameters were examined. It was found that with a higher rotation frequency νrot, smaller milling balls and a milling ball filling degree ΦMB of approximately 0.3, the highest solubility could be reached and the milling time could be reduced. The use of milling vessels with larger diameter was beneficial. Variation of the milling ball material showed huge influence and a linear correlation between solubility and density of the milling ball material was observed. Kinetic investigations indicate that the degradation of the impregnated cellulose follows a first order model.
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Influence of reaction parameters on the depolymerization of H 2 SO 4 -impregnated cellulose in planetary ball mills
Powder Technology, 2016Co-Authors: Robert Schmidt, Sindy Fuhrmann, Lothar Wondraczek, Achim StolleAbstract:Abstract The depolymerization of acid-impregnated cellulose in planetary ball mills was investigated under the perspective of the influence of reaction parameters. Several process, technological and chemical parameters were examined. It was found that with a higher rotation frequency νrot, smaller milling balls and a milling ball filling degree ΦMB of approximately 0.3, the highest solubility could be reached and the milling time could be reduced. The use of milling vessels with larger diameter was beneficial. Variation of the milling ball material showed huge influence and a linear correlation between solubility and density of the milling ball material was observed. Kinetic investigations indicate that the degradation of the impregnated cellulose follows a first order model.
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effect of reaction parameters on the synthesis of 5 arylidene barbituric acid derivatives in ball mills
Organic Process Research & Development, 2015Co-Authors: Robert Schmidt, Christine Friederike Burmeister, Matej Balaž, Arno Kwade, Achim StolleAbstract:The influence of crucial reaction parameters on Knoevenagel condensation in planetary ball mills was investigated. Rotation frequency (νrot), milling ball diameter (dMB), milling ball filling degree (ΦMB), and beaker size had obvious influences on yield. It was found that higher νrot, lower dMB, milling beakers with larger diameter, and a ΦMB of ∼0.3 are advantageous for the reaction. Furthermore, the influence of the type of mill was investigated, including reactions performed in different planetary and mixer ball mills, in a stirred media mill, and with a mortar mill. Comparisons with the other solvent-free synthetic routes showed that ball milling is an effective way of performing the reaction with low energy intensity.
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scale up of organic reactions in ball mills process intensification with regard to energy efficiency and economy of scale
Faraday Discussions, 2014Co-Authors: Achim Stolle, Robert Schmidt, Katharina JacobAbstract:The scale-up of the Knoevenagel-condensation between vanillin and barbituric acid carried out in planetary ball mills is investigated from an engineering perspective. Generally, the reaction proceeded in the solid state without intermediate melting and afforded selectively only one product. The reaction has been used as a model to analyze the influence and relationship of different parameters related to operation in planetary ball mills. From the viewpoint of technological parameters the milling ball diameter, dMB, the filling degree with respect to the milling balls' packing, ΦMB,packing, and the filling degree of the substrates with respect to the void volume of the milling balls' packing, ΦGS, have been investigated at different reaction scales. It was found that milling balls with small dMB lead to higher yields within shorter reaction time, treaction, or lower rotation frequency, rpm. Thus, the lower limit is set considering the technology which is available for the separation of the milling balls from the product after the reaction. Regarding ΦMB,packing, results indicate that the optimal value is roughly 50% of the total milling beakers' volume, VB,total, independent of the reaction scale or reaction conditions. Thus, 30% of VB,total are taken by the milling balls. Increase of the initial batch sizes changes ΦGS significantly. However, within the investigated parameter range no negative influence on the yield was observed. Up to 50% of VB,total can be taken over by the substrates in addition to 30% for the total milling ball volume. Scale-up factors of 15 and 11 were realized considering the amount of substrates and the reactor volume, respectively. Beside technological parameters, variables which influence the process itself, treaction and rpm, were investigated also. Variation of those allowed to fine-tune the reaction conditions in order to maximize the yield and minimize the energy intensity.
Shuchie Hsu - One of the best experts on this subject based on the ideXlab platform.
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comparative eco efficiency analysis on asphalt pavement rehabilitation alternatives hot in place recycling and milling and filling
Journal of Cleaner Production, 2019Co-Authors: Ruiju Cao, Zhe Leng, Shuchie HsuAbstract:Abstract With the ever-increasing road mileages worldwide, the focus of pavement construction has been shifted from new pavement construction to pavement maintenance and rehabilitation (M&R). The corresponding huge environmental burdens and capital consumptions posed big challenges in achieving the target of sustainable development. In this study, an eco-efficiency analysis (EEA) framework was developed and applied to compare two common asphalt pavement rehabilitation techniques: hot-in-place recycling (HIRP) and milling-and-filling (M&F), by integrating the life cycle assessment (LCA) and life cycle costing analysis (LCCA), which followed by a sensitivity analysis to investigate the eco-efficiency performances of the two alternatives under different life extension scenarios. The eco-efficiency portfolio positions of hot-in-place recycling and milling-and-filling provided by the eco-efficiency analysis clearly indicated that hot-in-place recycling was more eco-efficient than milling-and-filling under the same assumed service life (15 years) for the cases studied. Hot-in-place recycling could save 5% cost and reduce 16% overall environmental impacts than milling-and-filling, while milling-and-filling saved 7% energy consumption than hot-in-place recycling. When the life extension ratio of the two alternatives reaches 12/15 (HIPR/M&F), milling-and-filling starts to show its advantages in both environmental and economic aspects in the long-term perspective. These findings indicated that if the hot-in-place recycling technique could ensure its treatment effectiveness. Its wider adoption would be championed for more sustainable transportation infrastructure development. The method and results of this study were expected to serve as a reference for decision-makers to make well-informed project decisions on the optimum rehabilitation alternative from the view of eco-efficiency.
Ruiju Cao - One of the best experts on this subject based on the ideXlab platform.
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comparative eco efficiency analysis on asphalt pavement rehabilitation alternatives hot in place recycling and milling and filling
Journal of Cleaner Production, 2019Co-Authors: Ruiju Cao, Zhe Leng, Shuchie HsuAbstract:Abstract With the ever-increasing road mileages worldwide, the focus of pavement construction has been shifted from new pavement construction to pavement maintenance and rehabilitation (M&R). The corresponding huge environmental burdens and capital consumptions posed big challenges in achieving the target of sustainable development. In this study, an eco-efficiency analysis (EEA) framework was developed and applied to compare two common asphalt pavement rehabilitation techniques: hot-in-place recycling (HIRP) and milling-and-filling (M&F), by integrating the life cycle assessment (LCA) and life cycle costing analysis (LCCA), which followed by a sensitivity analysis to investigate the eco-efficiency performances of the two alternatives under different life extension scenarios. The eco-efficiency portfolio positions of hot-in-place recycling and milling-and-filling provided by the eco-efficiency analysis clearly indicated that hot-in-place recycling was more eco-efficient than milling-and-filling under the same assumed service life (15 years) for the cases studied. Hot-in-place recycling could save 5% cost and reduce 16% overall environmental impacts than milling-and-filling, while milling-and-filling saved 7% energy consumption than hot-in-place recycling. When the life extension ratio of the two alternatives reaches 12/15 (HIPR/M&F), milling-and-filling starts to show its advantages in both environmental and economic aspects in the long-term perspective. These findings indicated that if the hot-in-place recycling technique could ensure its treatment effectiveness. Its wider adoption would be championed for more sustainable transportation infrastructure development. The method and results of this study were expected to serve as a reference for decision-makers to make well-informed project decisions on the optimum rehabilitation alternative from the view of eco-efficiency.
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eco efficiency analysis on asphalt pavement rehabilitation alternatives hot in place recycling hipr and milling and filling m f
DEStech Transactions on Engineering and Technology Research, 2017Co-Authors: Ruiju Cao, Zhe Leng, Mark Shuchie HsuAbstract:With the ever-increasing road mileages worldwide, the focus of pavement construction has been shifted from new pavement to pavement maintenance and rehabilitation. A big challenge faced by achieving pavement construction sustainability is the huge consumption of capital, energy and non-renewable materials. In this study, an integrated eco-efficiency analysis (EEA) framework was developed and applied to compare two common asphalt pavement rehabilitation methods: hot-in-place recycling (HIRP) and milling-and-filling (M&F), for a real project. It was found that HIPR saved 5% cost and reduced 16% overall environmental impacts than M&F, while M&F saved 7% energy consumption than HIPR. The portfolio positions of HIPR and M&F provided by the EEA clearly indicate that HIPR is more eco-efficient than M&F for the studied project.
Lihui Zhou - One of the best experts on this subject based on the ideXlab platform.
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characterization of grain quality and starch fine structure of two japonica rice oryza sativa cultivars with good sensory properties at different temperatures during the filling stage
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Changquan Zhang, Lihui Zhou, Huwen Lu, Xingzhong Zhou, Yiting Qian, Qianfeng Li, Yan Lu, Minghong GuAbstract:Temperature during the growing season is a critical factor affecting grain quality. High temperatures at grain filling affect kernel development, resulting in reduced yield, increased chalkiness, reduced amylose content, and poor milling quality. Here, we investigated the grain quality and starch structure of two japonica rice cultivars with good sensory properties grown at different temperatures during the filling stage under natural field conditions. Compared to those grown under normal conditions, rice grains grown under hot conditions showed significantly reduced eating and cooking qualities, including a higher percentage of grains with chalkiness, lower protein and amylose contents, and higher pasting properties. Under hot conditions, rice starch contained reduced long-chain amylose (MW 107.1 to 107.4) and significantly fewer short-chain amylopectin (DP 5–12) but more intermediate- (DP 13–34) and long- (DP 45–60) chain amylopectin than under normal conditions, as well as higher crystallinity and gela...
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characterization of grain quality and starch fine structure of two japonica rice oryza sativa cultivars with good sensory properties at different temperatures during the filling stage
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Changquan Zhang, Lihui Zhou, Xingzhong Zhou, Yiting Qian, Zhengbin Zhu, Qiaoquan LiuAbstract:Temperature during the growing season is a critical factor affecting grain quality. High temperatures at grain filling affect kernel development, resulting in reduced yield, increased chalkiness, reduced amylose content, and poor milling quality. Here, we investigated the grain quality and starch structure of two japonica rice cultivars with good sensory properties grown at different temperatures during the filling stage under natural field conditions. Compared to those grown under normal conditions, rice grains grown under hot conditions showed significantly reduced eating and cooking qualities, including a higher percentage of grains with chalkiness, lower protein and amylose contents, and higher pasting properties. Under hot conditions, rice starch contained reduced long-chain amylose (MW 10(7.1) to 10(7.4)) and significantly fewer short-chain amylopectin (DP 5-12) but more intermediate- (DP 13-34) and long- (DP 45-60) chain amylopectin than under normal conditions, as well as higher crystallinity and gelatinization properties.
Shadrack O Nyawade - One of the best experts on this subject based on the ideXlab platform.
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effect of potato Hilling on soil temperature soil moisture distribution and sediment yield on a sloping terrain
Soil & Tillage Research, 2018Co-Authors: Shadrack O Nyawade, N K Karanja, Charles K K Gachene, Elmar Schultegeldermann, M ParkerAbstract:Abstract Soil erosion rates are exacerbated in sloping arable lands of Central Kenya due mainly to the high soil disturbance caused by potato Hilling. A field study was conducted in runoff plots to quantify the effect of potato Hilling on soil loss, soil moisture distribution and soil temperature. Three Hilling practices; Hilling performed at before crop emergence (pre-Hilling), one-pass Hilling (at 15 days after potato emergence), the conventional two-pass Hilling (at 15 and 30 days after potato emergence), and the control (non-Hilling) constituted the treatments. Root length density, vegetal cover, soil surface roughness and soil water infiltration capacity were quantified at different stages of potato growth and related with the sediment yield. Soil temperature and soil moisture contents were monitored using Onset HOBO sensor probes throughout the potato growth cycle. Compared to the conventional two-pass Hilling, pre-Hilling increased the soil moisture content by 6% and lowered the soil temperature by up to 3.4 °C at crop emergence, thus optimized tuber germination and growth. This ensured earlier canopy closure and reduced the cumulative sediment yield by 12 t/ha. The increased surface roughness resulting from pre-hilled ridges puddled the surface water and increased the soil water infiltration rate by 7 to 9 mm/hr compared to the non-hilled plots. Planting potatoes in pre-hilled plots has a potential to optimize the soil temperature and soil moisture conditions and can reduce the high soil erosion rates in sloping arable lands.