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Tuning thermal release kinetics of soy oil from organic nanoparticles using variable synthesis conditions

1981年

作者： Kor van Werkum Ger van Stokkum robert Druce.

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Particuology 2016年第3期14卷 54-65页

作者： Pieter Samyn Dieter van Nieuwkerke Vibhore Rastogi Dirk Stanssens University of Freiburg Freiburg Research Institute for Advances Studies (FRIAS) Faculty for Environment and Natural Resources Chair of Bio-based Materials Engineering Werthmannstrasse 6 D-79085 Freiburg Germany Ghent University Department of Textiles Technologiepark 907 B-9052 Zwijnaarde Belgium Topehim N.K Nijverheidsstraat 98 B-2160 Wommelgem Belgium

The thermal release properties of soy oil from poly（styrene-co-maleimide） nanoparticles containing 50 wt% encapsulated oil have been quantified as a function of temperature and time. The effects of dif- ferent synthesis conditions on the thermal stability of the nanoparticles and their oil release have been evaluated, i.e., by gradually increasing the amount of ammonium hydroxide used for the imidization of poly（styrene-co-maleic anhydride）. First, the intrinsic thermal properties of the oil-filled nanoparti- cles were analysed by differential scanning calorimetry, which revealed an exothermal reaction related to the oil release and a suppression of the glass transition that may be masked owing to the complex structure of the hybrid nanoparticles. The isothermal scans showed different rates of oil release after a post-imidization reaction. The oil release was better followed by dynamic mechanical analysis, which illustrated changes in visco-elastic properties expressed by the maximum in the loss factor that related to the amount of released oil. Depending on the amount of ammonium hydroxide, the oil started to release below the glass transition temperature at various rates. Thermal release profiles of the oil we re quantified by infrared and Raman spectrocopy after heating for 2 min to 6 h at 125 to 250 ℃, based on variations in oil-related and imide-related absorption bands. The oil release increased below and above the glass transition temperature, following a parabolic trend, and progressively decreased at higher ammonium hydroxide concentrations, in parallel with higher imide content and changes in imide conformation. The kinetics and mechanism of the oil release can be described by the Korsmeyer-Peppas model, suggesting a dominating diffusion mechanism that is influenced by further imidization of the polymer matrix during heating.

关键词： Soy oil Nanoparticle Encapsulation Release

Forces and energetics of intermittent swimming

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Acta Mechanica Sinica 2017年第4期33卷 725-732页

作者： Daniel Floryan Tyler van Buren Alexander J.Smits Department of Mechanical and Aerospace Engineering Princeton University Princeton NJ 08544 USA

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry（PIV） flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

关键词： intermittent swimming maintained conclusion cycle thrust favorable producing aquatic circles

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迷宫奇案

2018年

作者： (荷)高罗佩(robert van Gulik)

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新西兰2016年凯库拉M_W7.8地震地表破裂带特征初析

2018年

作者： (荷)高罗佩(robert van Gulik)

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地震地质 2017年第4期39卷 675-688页

作者：韩竹军 Nicola Litchfield 冉洪流袁仁茂郭鹏 robert M Langridge Russ J van Dissen 中国地震局地质研究所北京100029 Institute of Geological and Nuclear Science Lower Hutt 5010New Zealand

新西兰2016年凯库拉M_W7.8地震地表破裂带分布在1个长约170km、宽35km的范围内,总体呈NE-SW走向,至少有12条断裂产生了m量级的地表位错,跨过了2个活动方式与活动强度存在明显差异的地震构造区。地震地表断裂大致可分为NE—NEE向和NNW—... 详细信息

新西兰2016年凯库拉M_W7.8地震地表破裂带分布在1个长约170km、宽35km的范围内,总体呈NE-SW走向,至少有12条断裂产生了m量级的地表位错,跨过了2个活动方式与活动强度存在明显差异的地震构造区。地震地表断裂大致可分为NE—NEE向和NNW—近SN向2组,NE—NEE向断裂之间的贯通性差,最大相隔距离为25~30km,即使首尾相连,走向上也有约30°的差异,运动性质以右旋走滑为主,最大位错量10~12m;NNW—近SN向断裂近于平行分布,相距可达40~50km,以逆断裂活动性质为主,最大垂直位错量5~6m。走滑类地表破裂带的组合特征非常复杂,主要表现为3种形式:雁列、分叉和平行分布。其中,雁列地表破裂(段)既可以表现为数m至数十m尺度上的张剪性破裂与鼓包、挤压剪切破裂组合,也可表现为百余m长的左阶斜列张剪性破裂组合;地表破裂段之间阶区规模差异明显,可以是数十m、数百m到数km不等。平行的地表破裂(段)可以相距数m、数十m至数km。凯库拉地震地表破裂带对已知活动断裂分布格局的突破也是1种比较显著的特点,既可以是在原先认为不活动的断裂上或没有活动断裂的位置上产生了地表破裂带,也可以是在走向或横向上突破了先前认识到的活动断裂分布范围。对凯库拉地震地表破裂带发育特征的初步分析结果,对于理解地表活动断裂与深部发震构造之间复杂的对应关系,以及跨活动断裂的抗震设防等问题具有一定的借鉴意义。

关键词：凯库拉MW7.8地震地表破裂带地震构造活动断裂避让带

Growing Season and Phenological Stages of Small Grain Crops in Response to Climate Change in Alaska

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American Journal of Climate Change 2021年第4期10卷 490-511页

作者： Mingyuan Cheng Mingchu Zhang robert Mark van Veldhuizen Charles Winsett Knight Agricultural and Forestry Experiment Station University of Alaska Fairbanks Fairbanks USA Division of Agriculture Alaska Department of Natural Resources Division of Agriculture Fairbanks USA

The climate change in Alaska has caused earlier spring snowmelt and the growing season expanded. However, the effect of climate change on crop phenological stages, heading (BBCH 55) and maturity (BBCH 85), is unknown. In this study, the trends of growing-season length (GSL), phenological stages of crops and climatic parameters, and the correlations between climatic parameters and the phenological stages were analyzed using the climate data and crop data over the period of 1978 to 2016. The longer GSL was found in Fairbanks (64.83˚N, 147.77˚W) and in Delta Junction (64.05˚N, 145.60˚W) but not in Palmer (61.60˚N, 149.11˚W). Sowing dates did not change significantly in three locations. The decreasing trends of heading and maturity of crops were observed but varied with location. Heading of barley and oat significantly advanced 3 and 3.1 d decade-1, respectively from 1989 to 2016 in Fairbanks while no change of heading was observed in Delta Junction and Palmer. Maturity of barley, oat and wheat significantly advanced 2.6, 3.8 and 3.9 d decade-1, respectively from 1978 to 2016 in Fairbanks (P < 0.05);maturi

关键词： Heading Maturity Climate Change Growing-Season Length Growing Degree Days

On the numerical analysis of bed-load transport of saltating grains

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International Journal of Sediment Research 2013年第3期28卷 413-420页

作者： robert J.BIALIK Wlodzimierz CZERNUSZENKO Emeritus Department of Hydrology and Hydrodynamics Institute of GeophysicsPolish Academy of SciencesKs.Janusza 6401-452 WarsawPoland

The focus of this paper is on the analysis of the influence of particles' velocity distribution and their concentration on the sediment transport rate in bed-load from the Lagrangian *** aims are addressed by use of the relevant Lagrangian model of spherical saltating particles in which turbulence plays a significant *** Monte Carlo approach is employed in the simulations to obtain the velocity and concentration of the saltating *** simulations using two saltating particle models:(1) with;and(2) without particle-particle collisions are carried *** on the numerical results,we address the hypothesis that instead of averaged characteristics,the distributions of particles' velocity and sediment concentration should be taken into account in the calculation of sediment transport ***,our results also show that the interaction between particles during their collisions is the key for better understanding of the physics of sediment *** results are compared with well-known experimental formulae ***-Peter and Muller and Fernandez Luque and van Beek.

关键词： Bed-load transport Lagrangian approach Inter-particle collisions Saltation Sediment concentration

A Novel Indirect Parabolic Solar Cooker

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Journal of Electrical Engineering 2017年第3期5卷 137-142页

作者： Omotoyosi O. Craig robert T. Dobson Wikus van Niekerk Solar Thermal Energy Research Group Stellenbosch University Stellenbosch 7602 South Africa Mechanical and Mechatronics Engineering Department Stellenbosch University Stellenbosch 7602 South Africa Centre for Renewable and Sustainable Energy Studies Stellenbosch University Stellenbosch 7602 South Africa

The continuous increase in global demand and cost of electricity are some of the reasons that solar cooking has received much attention recently. Another factor which has also contributed to the acceptance of solar cookers is global campaigns against actions that contribute to climate change. Various types of solar cookers are currently in existence, these are box, panel and parabolic cookers. Some solar cookers only function when the cooking section is placed under direct sunshine, while others have been modified to cook without directly exposing their cooking section to the sun. Most solar cookers face similar challenges, and these include, exposure of users to sun, inability to function at night or when there is no sunshine, low utilization efficiency and technical complexities. This report presents an indirect parabolic cooker that eliminates the identified solar cooker challenges. The cooker uses a parabolic reflector to focus the sun rays to a frustum shaped receiver that was placed at its focus. The cooker has an insulated cooking/heat storage tank which was separated from the dish and cavity receiver system. The heat transfer fluid was distributed through the system with the aid of high temperature flexible hoses. Several cooking tests including water boiling and pancake baking were done, an extensive analysis of cooking based on the international testing procedures for solar cookers was also carried out. This solar cooker had a utilization efficiency of 39%, an overall calculated exergy efficiency of 0.05% and an average characteristic boiling time of approximately 13 minutes/kg. The manufactured solar cooker in this study was used for family cooking.

关键词： Parabolic dish cavity receiver indoor cooking utilization efficiency.

Defective recovery of QT dispersion following transcatheter aortic valve implantation： frequency, predictors and prognosis

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Journal of Geriatric Cardiology 2015年第5期12卷 482-488页

作者： Rutger-Jan Nuis Gokhan Turgut robert M van der Boon Nicolas M van Mieghem Sjoerd T Nauta Patrick W Serruys Ron T van Domburg Giulio Zuchelli Luc Jordaens Peter P de Jaegere Department of Cardiology Erasmus University Medical Center Rotterdam the Netherlands Department of Electrophysiology Erasmus Thoraxcenter Rotterdam the Netherlands Department of Biostatistics Erasmus Thoraxeenter Rotterdam the Netherlands Division of Cardiovascular Diseases Azienda Ospedaliero-Universitaria Pisana Pisa Italy

Background Corrected QT dispersion （cQTD） has been correlated with non-uniform ventricular repolarisation and increased mortality. In patients with aortic stenosis, cQTD has been shown improved after surgical valve replacement, but the effects of transcatheter aortic valve implantation （TAVI） are unknown. Therefore, we sought to explore the frequency, predictors and prognostic effects of defective cQTD recovery at 6 months after TAVI. Methods A total of 222 patients underwent TAVI with the Medtronic-CoreValve System between November 2005 and January 2012. Patients who were on class Ⅰ or Ⅲ antiarrhythmics or on chronic haemodialysis or who developed atrial fibrillation, a new bundle branch block or became pacemaker dependent after TAVI were excluded. As a result, pre-, post- and follow-up ECG （median： 6 months） analysis was available in 45 eligible patients. Defective cQTD recovery was defined as any progression beyond the baseline cQTD at 6 months. Results In the 45 patients, the mean cQTD was 47 ± 23 ms at baseline, 45 ±17 ms immediately after TAVI and 40 ± 16 ms at 6 months （15% reduction, P = 0.049）. Compared to baseline, cQTD at 6 months was improved in 60% of the patients whereas defective cQTD recovery was present in 40%. cQTD increase immediately after TAVI was an independent predictor of defective cQTD recovery at 6 months （per 10 ms increase; OR： 1.89, 95% CI： 1.15-3.12）. By univariable analysis, defective cQTD recovery was associated with late mortality （HR： 1.52, 95% CI： 1.05-2.17）. Conclusions Despite a gradual reduction ofcQTD after TAVI, 40% of the patients had defective recovery at 6 months which was associated with late mortality. More detailed ECG analysis after TAVI may help to avoid late death.

关键词： Aortic stenosis Conduction abnormalities Left bundle branch block Predictors QT dispersion Transcatheter aortic valve implantation