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DEM analysis of the influence of stirrer design on die filling with forced powder feeding

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Particuology 2024年第5期88卷 107-115页

作者： Chao Zheng Edward Yost ariel R.Muliadi Nicolin Govender Ling Zhang Chuan-Yu Wu School of Chemistry and Chemical Engineering University of SurreyGuildfordGU2 7XHUnited Kingdom Small Molecule Pharmaceutics GenentechInc.One DNA WaySouth San FranciscoCA94080USA

Die filling is a critical stage during powder compaction,which can significantly affect the product quality and *** this paper,a forced feeder is introduced attempting to improve the filling performance of a lab-scale die filling *** die filling process is analysed with a graphics processing units(GPU)enhanced discrete element method(DEM).Various stirrer designs are assessed for a wide range of process settings(i.e.,stirrer speed,filling speed)to explore their influence on the die filling performance of free-flowing *** results show that die filing with the novel helical-ribbon(i.e.,type D)stirrer design exhibits the highest filling ratio,implying that it is the most robust stirrer design for the feeder configuration ***,die filling performance with the type D stirrer design is a function of the stirrer speed and the filling speed.A positive variation of filling ratio(ηf>0%)can be ensured over the whole range of filling speed by adjusting the stirrer speed(i.e.,increasing the stirrer speed).The approach used in this study can not only help understand how the stirrer design affects the die filling performance but also guide the optimization of feeder system and process settings.

关键词： Discrete element method Die filling Forced feeding Stirrer design GPU computing

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岩石变形记忆效应:应用、试验与理论

岩土工程学报 2018年第9期40卷 1571-1583页

作者：王海军汤雷任旭华钟凌伟司富安 hsieh ariel 南京水利科学研究院水文水资源与水利工程国家重点试验室江苏南京210029 河海大学江苏南京210098 水利部水利水电规划设计总院北京100120 TheUniversityofWesternAustralia Perth6009Australia

基于岩石变形记忆效应DME＆DRA法,为准确便捷测量初始地应力提供了全新的思路,国际上及中国台湾的一系列实践应用证明了其巨大的潜力。但是,岩石变形记忆效应的研究和工程应用在中国（除中国台湾外）刚起步,同时,试验及理论的系统性研... 详细信息

基于岩石变形记忆效应DME＆DRA法,为准确便捷测量初始地应力提供了全新的思路,国际上及中国台湾的一系列实践应用证明了其巨大的潜力。但是,岩石变形记忆效应的研究和工程应用在中国（除中国台湾外）刚起步,同时,试验及理论的系统性研究整体上落后于工程应用,成为制约DME＆DRA法成熟和普及的瓶颈问题。因此,开展岩石变形记忆效应的应用、试验、理论的研究进展综述具有重要意义。首先给出岩石DME＆DRA法的基本概念,然后给出在国际上的应用实践现状;从7个方面的内容对试验研究进展进行系统性评述：（1）岩石变形记忆DRA曲线特征;（2）岩石变形记忆效应的失忆性;（3）人工记忆与地应力记忆;（4）初始加载保持时间;（5）初始加载重复次数;（6）记忆存在应力区域;（7）三维应力记忆特征;详细探讨各方面成果及不足;探讨了岩石变形记忆效应形成机理的两种认识及相应的理论模型,深入剖析现有研究结论与进展揭示存在的挑战,最终给出研究方向与建议。为推动国内开始开展岩石变形记忆效应的研究与应用提供基础。

关键词：初始地应力岩石变形记忆效应(DME) 变形率分析法(DRA法) 岩石力学研究进展

保持加载下岩石变形记忆效应时效特征规律研究

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岩石力学与工程学报 2020年第2期39卷 228-238页

作者：钟凌伟王海军任旭华汤雷 ariel hsieh 尹健民李永松河海大学水安全与水科学协同创新中心江苏南京210098 南京水利科学研究院水文水资源与水利工程国家重点试验室江苏南京210029 西澳大学澳大利亚珀斯6009 长江科学研究院湖北武汉430010

作为岩石基本属性的变形记忆效应(deformation memory effect,DME)具有时效特性,加载保持时间(Tc)对岩石DME的影响是其时效特性之一。选用砂岩及2种花岗岩材料,开展不同Tc下的物理试验,对记忆信息形成精度及应变差幅值等进行分析,并基... 详细信息

作为岩石基本属性的变形记忆效应(deformation memory effect,DME)具有时效特性,加载保持时间(Tc)对岩石DME的影响是其时效特性之一。选用砂岩及2种花岗岩材料,开展不同Tc下的物理试验,对记忆信息形成精度及应变差幅值等进行分析,并基于岩石内部多微结构面间的黏弹性摩擦滑动理论,采用岩石三元件构建基本记忆单元理论模型,进行不同Tc下DME力学理论研究,结果表明:(1)随Tc增加,2种花岗岩和砂岩的记忆信息形成精度明显提高,应变差幅值逐渐减小;(2)记忆理论模型的记忆信息形成精度和应变差幅值的变化规律和物理试验保持一致,即基于多微结构面的记忆理论模型能够描述不同Tc下的岩石DME宏观行为;(3)Tc增加到一定幅度时,记忆信息形成精度和应变差幅值趋于不变,并提出当应变差幅值稳定时,此时为最佳Tc。结论给出了保持加载下岩石DME时效特性变化规律,为岩石DME时效性研究提供了试验及理论基础。

关键词：岩石力学岩石变形记忆效应变形率变化法时效性加载保持时间多微结构面摩擦滑动

Elements of Electromagnetic Matter

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Journal of Modern Physics 2024年第3期15卷 250-270页

作者： Viktor ariel Independent Researcher Modiin Israel

Originally, Maxwell attempted to express his electromagnetic theory using four-dimensional mathematics of quaternions. Maxwell’s equations were later re-written in a three-dimensional real vector form, which is how the theory is presented today. Thus, an interesting question remains whether we can derive electromagnetic equations analytically from the basic mathematical principles of quaternion algebra and calculus, resulting in general and analytic matter equations. This question seems highly intriguing. Previously, we developed a mathematical theory of time using a normed division algebra of real quaternions [1]. In this study, we extend the theory of time by presenting a new analytical derivation of electromagnetic matter equations using the calculus of real quaternions, as originally intended by Maxwell. Therefore, we propose a novel mathematical definition of the quaternion path derivative using the properties of quaternion division. We then apply the quaternion derivative to an external electromagnetic potential and assume that the first quaternion derivative represents the quaternion electromagnetic force. Next, we assume that the second derivative, or quaternion Laplacian operator, applied to an external electromagnetic potential leads to the quaternion electromagnetic current density. The new analytical expressions are similar to the original empirical Maxwell equations, except for an additional scalar electric field, which allows for a novel formulation of Ohm’s conductivity law. We demonstrate that the resulting analytical equations can be written equivalently using either electromagnetic potentials or fields. Finally, we summarize the key postulates and equations of the new electromagnetic matter theory, which were based on normed division algebra and the calculus of quaternions. The resulting theory appears to be a useful analytical enhancement of the original Maxwell equations, and therefore, seems highly comprehensive, logical, and compelling.

关键词： Maxwell’s Equations Relativistic Electrodynamics Quaternion Calculus

Extreme drought triggers parallel shifts in wood anatomical and physiological traits in upper treeline of the Mediterranean Andes

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Ecological Processes 2024年第1期13卷 132-143页

作者： Luiz Santini Jr. Dylan Craven Daigard Ricardo Ortega Rodriguez Manolo Trindade Quintilhan Stephanie Gibson-Carpintero Cristina Aravena Torres Fidel A.Roig ariel A.Mu?oz Alejandro Venegas-Gonzalez Hémera Centro de Observación de la Tierra Universidad Mayor GEMA Center for Genomics Ecology and Environment Universidad Mayor Data Observatory Foundation ANID Technology Center Depart-ment of Forest Sciences ESALQ-University of Sao Paulo Department of Plant Biology Institute of Biology University of Campinas Instituto de Geografía Universidad Nacional Autónoma de México (UNAM) Argentine Institute of Nivology Glaciology and Environmental Sciences(IANIGLA CONICET ) Institute of Geography Pontificia Universidad Católica de Valparaíso Instituto de Ciencias Agroalimentarias Animales y Ambientales (ICA3) Universidad de O'Higgins

Background Treeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts. Even though the effect of droughts on forest dynamics has been widely documented, knowledge is relatively scarce of how extreme climate episodes affect the hydraulic structure and, therefore, the phys-iology of woody plants. The Mediterranean Andes have experienced an uninterrupted period of drought since 2010, including an extremely dry year in 2019 with approximately 80% rainfall deficit. Here, we investigated shifts in wood anatomical and physiological traits of Kageneckia angustifolia, an endemic treeline species, in response to this drought *** We evaluated the xylem plasticity of three K. angustifolia populations across their natural distribution(31–35° SL) based on anatomical(vessel structure and distribution) and physiological(intrinsic water-use efficiency) variables in the tree rings. We focused on the period 2000–2020 that corresponds to before the megadrought(2000–2007),(ii) megadrought(2008–2018) and(iii) hyperdrought(2019–2020). The variables were annualized and analyzed by linear mixed-effects *** Our results provide insights to the anatomical and physiological mechanisms underlying the resilience of treeline forests to persistent droughts in central Chile. We found that the extreme drought in 2019–2020 triggered shifts in vessel size and frequency that increased hydraulic safety. These significant shifts in vessel traits occurred in parallel with a decrease in pit aperture area and an increase in water-use efficiency, further increasing the resilience of K. angustifolia to extreme drought *** Our results revealed coordinated shifts in vessel size and frequency and water-use efficiency in response to the megadrought, thereby reducing vulnerability to hydraulic failure. The apparent resilience of K. angustifolia to extreme droughts suggests that this adaptation to drought stress may incre

关键词： Dendro-anatomy Kageneckia angustifolia Xylem vulnerability Drought Climate change

Sex-dependent resilience to extreme drought events: implications for climate change adaptation of a South American endangered tree species

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Ecological Processes 2024年第2期 48-60页

作者： Sergio Piraino Martín ariel Hadad Yanina Antonia Ribas-Fernández Fidel Alejandro Roig Laboratorio de Dendrocronología e Historia Ambiental (IANIGLA CONICET ) Facultad de Ciencias Agrarias Universidad Nacional de Cuyo Laboratorio de Dendrocronología de Zonas áridas (CIGEOBIO CONICET ) Gabinete de Geología Ambiental (INGEO UNSJ) Hémera Centro de Observación de la Tierra Facultad de Ciencias Universidad Mayor

Background Recent changes in climatic trends are resulting in an increased frequency and intensity of extreme events, with unknown effect on ecosystem dynamics in the near future. Extreme drought episodes are recognized as disturbance factors capable of modifying forest dynamics and tree growth. Within this context, dioecious tree species may be impacted by climatic extremes, affecting male/female proportions and, consequently, reproductive processes and species persistence. Therefore, there is an urgent need for species-specific assessments of growth tolerance to extreme dry spells in dioecious tree species, to establish effective conservation strategies for these particular natural resources. Araucaria araucana(araucaria), an endangered dioecious Patagonian tree species, has recently undergone decay and mortality episodes in response to increasing dry climatic conditions. While sex-dependent tolerance to extreme drought episodes has been assessed in the species' humid distribution range, there is still a lack of information on the gender-based resilience of trees growing in the drier environments of the species' *** We reconstructed, through dendrochronological methods, the sex-dependent response of 105 araucaria individuals(55 female and 50 male trees) to five regional extreme dry spells employing a set of different indices. Resistance, recovery period, and average growth reduction of standardized tree-ring growth were examined, analysing the effect of biotic(sex, pre-drought stem tree growth) and abiotic(local climatic conditions before, during, and after extreme climatic episodes) factors on tree *** Sex influences only the species resistance to climatic disturbance, with male individuals showing lower tolerance to extreme drought events. Pre-drought radial growth rates and local meteorological conditions preceding, during, and following extreme dry spells strongly modulated araucaria radial growth resilience regardless of tree s

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Comparative Analysis of Statistical Thickness Models for the Determination of the External Specific Surface and the Surface of the Micropores of Materials: The Case of a Clay Concrete Stabilized Using Sugar Cane Molasses

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Geomaterials 2024年第2期14卷 13-28页

作者： Nice Mfoutou Ngouallat Narcisse Malanda Christ ariel Ceti Malanda Kris Berjovie Maniongui Erman Eloge Nzaba Madila Paul Louzolo-Kimbembe Mechanics Energy and Engineering Laboratory Higher National Polytechnic School Marien Ngouabi University Brazzaville Republic of the Congo National Institute for Research in Engineering Sciences Innovation and Technology (INRSIIT) Brazzaville Republic of the Congo Higher Institute of Architecture Building Planning and Public Works Denis SASSOU N&#8217GUESSO University Kint&#233l&#233 Republic of the Congo Hydrogen Research Institute University of Quebec in Trois Rivieres Quebec Canada Superior Normal School (ENS) Marien Ngouabi University Brazzaville Republic of the Congo

In this work, four empirical models of statistical thickness, namely the models of Harkins and Jura, Hasley, Carbon Black and Jaroniec, were compared in order to determine the textural properties (external surface and surface of micropores) of a clay concrete without molasses and clay concretes stabilized with 8%, 12% and 16% molasses. The results obtained show that Hasley’s model can be used to obtain the external surfaces. However, it does not allow the surface of the micropores to be obtained, and is not suitable for the case of simple clay concrete (without molasses) and for clay concretes stabilized with molasses. The Carbon Black, Jaroniec and Harkins and Jura models can be used for clay concrete and stabilized clay concrete. However, the Carbon Black model is the most relevant for clay concrete and the Harkins and Jura model is for molasses-stabilized clay concrete. These last two models augur well for future research.

关键词： Statistical Thickness Model External Specific Surface Microporous Surface Clay Concrete Molasses

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通用汽车想为车载系统另起炉灶

商业周刊（中文版） 2024年第7期 56-61页

作者： AUSTIN CARR DAVID WELCH ariel DAVIS(图) 汪泽(译) 不详

2024款雪佛兰开拓者EV(Chevrolet Blazer EV)是迈克尔·沃尔德伦(Michael Waldron)拥有过的最漂亮的座驾。他去年11月购买了这辆6.2万美元的电动SUV,深深地迷上了它的“炫红”色彩,丝滑流畅的加速以及豪华的内饰,简洁的显示屏排列在仪... 详细信息

2024款雪佛兰开拓者EV(Chevrolet Blazer EV)是迈克尔·沃尔德伦(Michael Waldron)拥有过的最漂亮的座驾。他去年11月购买了这辆6.2万美元的电动SUV,深深地迷上了它的“炫红”色彩,丝滑流畅的加速以及豪华的内饰,简洁的显示屏排列在仪表盘上。只是少了一样重要事物:苹果公司(Apple)的CarPlay。

关键词：车载系统仪表盘座驾通用汽车内饰 SUV 苹果公司沃尔德

Endoscopic ultrasound-guided gastroenterostomy for gastric outlet obstruction in Mexico

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World Journal of Surgical Procedures 2024年第3期14卷 15-20页

作者： Massiel Madelin Rosario-Morel Rodrigo Soto-Solis Katia Picazo-Ferrera Miriam Idalia Torres-Ruiz JoséAlberto Estradas-Trujillo Mario Alberto Gallardo-Ramírez Gerardo Akram Darwich-del Moral Luis ariel Waller-González Department of Endoscopy Centro Médico Nacional“20 de Noviembre”ISSSTEMexico City 03229Mexico Department of Gastroenterology HospitalÁngeles PedregalMexico City 10700Mexico Department of Endoscopy Centro Médico ABCMexico City 01120Mexico Department of Endoscopy Hospital General de México“Dr.Eduardo Liceaga”Mexico City 06720Mexico

BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)has recently emerged as an alternative treatment for gastric outlet obstruction(GOO)in selected *** To report the initial experience of EUS-GE in patients with *** This study was a retrospective,observational,multicenter study in which the data from 10 patients who underwent EUS-GE due to GOO between September 2021 and May 2023 were *** analyzed technical success,clinical success,adverse events,and *** success was defined as adequate positioning and deployment of the *** success was defined as the patient’s ability to tolerate oral intake without vomiting 7 d after the *** adverse events were *** Eleven procedures in 10 patients with GOO were *** mean age of the patients was 67.5 years(range:56-77 years).Malignant GOO was present in 9 *** success was achieved in 9/11 procedures(82%).Among them,clinical success was achieved in 9 patients(100%).Adverse events occurred in 1 patient(9%).The median survival was 3 months(n=7;range:1-8 months).CONCLUSION EUS-GE is a feasible therapeutic option in the treatment of GOO.

关键词： Endoscopic ultrasound-guided gastroenterostomy Gastric outlet obstruction Lumen apposing metal stent Interventional endoscopic ultrasound Gastrojejunostomy Duodenal stenting