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Solids motion in bubbling gas fluidised beds

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Solids motion in bubbling gas fluidised beds

CCAST“颗粒物理”研讨会

作者： M.Stein Y.L.ding J.P.K.Seville d.J.parker School of Chemical Engineering. University of Birmingham. Edgbaston. Birmingham B15 2TT. UK School of Chemical Engineering. University of Birmingham. Edgbaston Birmingham B15 2TT. UK Positron Imaging Centre University of Birmingham. Edgbaston Birmingham B15 2TT. UK School of Chemical Engineering. University of Birmingham. Edgbaston Birmingham B15 2TT. UK Positron Imaging Centre University of Birmingham. Edgbaston Birmingham B15 2TT. UK Positron Imaging Centre University of Birmingham. Edgbaston. Birmingham B15 2TT. UK School of Physics. University of Birmingham Edgbaston. Birmingham B15 2TT. UK

＜正＞ Gas fluidised beds are widely employed in the chemical, petrochemical, metallurgical, and pharmaceutical industries. Solids mixing in such devices plays a central role in controlling product quality and productivity. This paper presents some observations of particle motion in 3-d gas fluidised beds operated in the bubbling mode and at atmospheric pressure. The non-invasive positron emission particle tracking（PEPT） technique was used to observe and quantify particle trajectory, solids How pattern,solids velocity, and solids circulation frequency. It is shown that for relatively-deep beds （cylindrical columns, group B particles）, particles move upward in the central region, and downward near the wall. The average upward particle velocity is - 50% of the bubble velocity under the conditions of this study. Theoretical models are proposed to correlate the overall particle upward velocity and average particle velocity in the drift to the bubble velocity, and to estimate the duration of particle residence in the drift. Model predictions show reasonable agreement with experiments. It is suggested that solids motion in gas fluidised beds can be characterised by ’jump’, ’idle’ and ’relaxation’ times. These times may also be linked to particle kinetic energy transfer in lluidised beds. 2000 Elsevier Science Ltd. All rights reserved.

关键词： Gas fluidised bed Bubbling bed Solids motion Particle velocity Mixing PEPT

Solids motion in rolling mode rotating drums operated at low to medium rotational speeds

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Solids motion in rolling mode rotating drums operated at low...

CCAST“颗粒物理”研讨会

作者： Y.L.ding J.P.K.Seville R.Forster d.J.parker School of Chemical Engineering . Positron Imaging Centre University of Birntingham Edgbaston Birmingham B15 2TT. UK School of Chemical Engineering . Positron Imaging Centre University of Birntingham Edgbaston Birmingham B15 2TT. UK School of Physics and Astronomy. Positron Imaging Centre. University of Birmingham. Edgbaston Birmingham B15 2TT UK School of Physics and Astronomy. Positron Imaging Centre. University of Birmingham. Edgbaston Birmingham B15 2TT UK

＜正＞ The industrial-scale rotating drums are usually operated in the rolling or slumping mode. For the rolling mode, the granular material bed can be divided into two regions, namely, a ’passive’ region where particles are carried up by the drum wall, and an ’active’ region where particles cascade down. As solids mixing mainly occurs in the active region, solids motion in this region and solids exchange between the active and passive regions are of prime importance for the overall performance of the drum. This paper reports some observations on particle motion in the transverse plane of a three-dimensional rotating drum operated at low and medium rotational speeds. The non-invasive PEPT （positron emission particle tracking） technique is used to follow particle trajectory and velocity. A mathematical model based on the thin-layer approximation is proposed to describe solids motion in the active layer. Reasonable agreement between the model predictions and experiments is obtained. A new parameter termed the ’solids exchange coefficient is proposed to characterise particle exchange between the passive and active regions. A theoretical expression for this parameter is also derived. This expression, upon application of the thin-layer approximation, is reduced to give an explicit relationship between the solids exchange coefficient and drum operating parameters such as rotational speed and fill percentage. as well as the bed material rheological properties. The solids exchange coefficient is also shown to give a possible scale-up rule for rotating drums operated in a rolling mode, 2001 Elsevier Science Ltd. All rights reserved.

关键词： Solids motion Solids mixing Rotating drums Rolling mode PEPT

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稳定的异氰酸甲酯组成

湖南化工 1981年第3期 54-58页

作者： d.H.parker 曾宪泽湖南化工研究所

异氰酸甲酯,特别是被氨基甲酰氯沾污了的异氰酸甲酯,可使其中溶解重量为0.005—0.40%的酸式焦磷酸二烷基酸使其稳定,0.02%的酸式焦磷酸二甲酯更好,可

关键词：异氰酸甲酯稳定剂焦磷酸甲基碳酰亚胺农药助剂二磷酸酸式二烷基链烷基

金属推型V-带无级变速箱损耗机理仿真部分1:带组摩擦造成的转矩损失

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传动技术 2006年第1期20卷 47-48页

作者： S Akenurst N d Vaughan dA parker d Simner department of Mechanical Engineering University of Bath Bath UK department of Automotive Mechanical and Structures Engineering Cranfield University Cranfield UK Engineering Systems department Cranfield University (RMCS Shrivenham) Swindon UK

以推型金属带为基体的无级变速箱(CVT)的动力传递效率低于有级变速箱,大家已往认识到采用CVT改进发动机/负荷匹配新取得的燃料经济性的好处有被取消的趋势。本组三篇论文详细阐述了发生在作为第一级用来取得效率改进的带传动中损耗机理... 详细信息

以推型金属带为基体的无级变速箱(CVT)的动力传递效率低于有级变速箱,大家已往认识到采用CVT改进发动机/负荷匹配新取得的燃料经济性的好处有被取消的趋势。本组三篇论文详细阐述了发生在作为第一级用来取得效率改进的带传动中损耗机理的研究。已经进行试验研究了涉及推型金属V-带CVT空载和低载的转矩损失。本第一篇论文述及发生在金属带CVT由于带推块和带间相对运动造成主要转矩损失的新分析方法。本研究考虑到其他研究中的新发现并改进了金属V-带的设计。本文中采用几种不同的试验方法提供的实验数据推荐了转矩损失的数字模型。本组第二篇论文阐述了由于带轮变形的许多附加转矩损失机理。在第三篇论文中阐述了根据本文的发现提出带滑动损失的分析。

关键词：无级变速箱机械效率推型带损耗分析

Using quality improvement methods to increase use of pain prevention strategies for childhood vaccination

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World Journal of Clinical Pediatrics 2017年第1期6卷 81-88页

作者： Jennifer Verrill Schurman Amanda d deacy Rebecca J Johnson Jolynn parker Kristi Williams dustin Wallace Mark Connelly Lynn Anson Kevin Mroczka division of developmental and Behavioral Sciences Children's Mercy Primary Care Clinic Children’s Mercy division of General Academic Pediatrics Children’s Mercy Comprehensive Pain Management Children’s Mercy department of Pediatrics Children’s Mercy

AIM To increase evidence-based pain prevention strategy use during routine vaccinations in a pediatric primary care clinic using quality improvement *** Specific intervention strategies(i.e.,comfort positioning,nonnutritive sucking and sucrose analgesia,distraction) were identified,selected and introduced in three waves,using a Plan-do-Study-Act ***-wide change was measured from baseline to post-intervention by:(1) percent of vaccination visits during which an evidence-based pain prevention strategy was reported as being used; and(2) caregiver satisfaction ratings following the ***,self-reported staff and caregiver attitudes and beliefs about pain prevention were measured at baseline and 1-year post-intervention to assess for possible long-term cultural *** Significant improvements were noted *** of at least one pain prevention strategy was documented at 99% of patient visits and 94% of caregivers were satisfied or very satisfied with the pain prevention care ***/caregivers reported greater satisfaction with the specific pain prevention strategy used [t(143) = 2.50,P ≤ 0.05],as well as greater agreement that the pain prevention strategies used helped their children's pain [t(180) = 2.17,P ≤ 0.05] and that they would be willing to use the same strategy again in the future [t(179) = 3.26,P ≤ 0.001] as compared to *** and caregivers also demonstrated a shift in attitudes from baseline to 1-year ***,staff reported greater agreement that the pain felt from vaccinations can result in harmful effects [2.47 vs 3.10; t(70) =-2.11,P ≤ 0.05],less agreement that pain from vaccinations is "just part of the process" [3.94 vs 3.23; t(70) = 2.61,P ≤ 0.05],and less agreement that parents expect their children to experience pain during vaccinations [4.81 vs 4.38; t(69) = 2.24,P ≤ 0.05].Parents/caregivers reported more favorable attitudes about pain prevention st

关键词： Pediatrics Quality improvement distraction Pain management Immunization Vaccination Sucrose analgesia Pain prevention Non-nutritive sucking Comfort positioning Primary care

Segregation of granular flow in the transverse plane of a rolling mode rotating drum

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Segregation of granular flow in the transverse plane of a ro...

CCAST“颗粒物理”研讨会

作者： Y.L.ding R.Forster J.P.K.Seville d.J.parker School of Chemical Engineering. University of Birmingham Edgbaston. Birmingham B15 2TT UK Positron Imaging Centre. University of Birmingham. Edgbaston Birmingham B15 2TT. UK School of Physics and Astronomy University of Birmingham. Edghaston. Birmingham B15 2TT UK Positron Imaging Centre. University of Birmingham Edgbuston. Birmingham B15 2TT. UK School of Chemical Engineering. University of Birmingham. Edgbaston. Birmingham B15 2TT UK Positron Imaging Centre University oj Birmingham Edgbaston Birmingham B15 2TT. UK School of Physics and Astronomy University of Birmingham. Eagbaston. Birmingham B15 2TT UK Positron Imaging Centre. University of Birmingham. Edgbaston. Birmingham B15 2TT. UK

＜正＞ This paper reports some observations on the behaviour of a segregated particle bed consisting of a mixture of small and large particles in the transverse plane of a rolling mode rotating drum. A non-invasive positron emission particle tracking （PERT） technique was used to follow the trajectories of different sized particles. A two-dimensional mathematical model based on the Eulerian approach and the thin layer approximation was developed to simulate solids motion and concentration distribution of different sized particles. It is shown that the bed structure for a binary mixture is similar to that for mono-sized particles, i.e. two-region structure consisting of a relatively thin ’active’ region and a ’passive’ region near the drum wall where particles move as a rigid body. At low rotational speeds, the velocity difference between small and large particles of a binary system is negligible in both the active and passive regions. At relatively high rotational speeds, the velocity difference is small in the active region and negligible in the passive region. Radial occupancy data suggest that small particles tend to concentrate in the core region, whereas large particles tend to occupy the shell region, in good agreement with model predictions. Axial occupancy data reveal that the axial particle mobility increases with drum rotational speed, and the mutual diffusivity of small particles is higher than that of large particles. It is also shown that the turnover time ratio of small to large particles is almost independent of concentrations of small particles under the conditions of this work. 2002 Elsevier Science Ltd. All rights reserved.

关键词： Particle segregation Solids motion Rotating drum Rolling mode Bed turnover time Mathematical modelling PEPT

Two-step machine learning enables optimized nanoparticle synthesis

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npj Computational Materials 2021年第1期7卷 498-507页

作者： Flore Mekki-Berrada Zekun Ren Tan Huang Wai Kuan Wong Fang Zheng Jiaxun Xie Isaac parker Siyu Tian Senthilnath Jayavelu Zackaria Mahfoud daniil Bash Kedar Hippalgaonkar Saif Khan Tonio Buonassisi Qianxiao Li Xiaonan Wang department of Chemical and Biomolecular Engineering National University of SingaporeSingaporeSingapore Singapore-MIT Alliance for Research and Technology SMART SingaporeSingapore Institute for Infocomm Research Agency for ScienceTechnology and Research(A*STAR)SingaporeSingapore Institute of Materials Research&Engineering SingaporeSingapore department of Materials Science and Engineering Nanyang Technological UniversitySingaporeSingapore Massachusetts Institute of Technology CambridgeMAUSA department of Mathematics National University of SingaporeSingaporeSingapore Institute of High Performance Computing SingaporeSingapore

In materials science,the discovery of recipes that yield nanomaterials with defined optical properties is costly and *** this study,we present a two-step framework for a machine learning-driven high-throughput microfluidic platform to rapidly produce silver nanoparticles with the desired absorbance *** a Gaussian process-based Bayesian optimization(BO)with a deep neural network(dNN),the algorithmic framework is able to converge towards the target spectrum after sampling 120 *** the dataset is large enough to train the dNN with sufficient accuracy in the region of the target spectrum,the dNN is used to predict the colour palette accessible with the reaction *** remaining interpretable by humans,the proposed framework efficiently optimizes the nanomaterial synthesis and can extract fundamental knowledge of the relationship between chemical composition and optical properties,such as the role of each reactant on the shape and amplitude of the absorbance spectrum.

关键词： spectrum synthesis. synthesis

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教学勇气

教学勇气

2020年

作者： (美)帕克·帕尔默(parker J. Palmer)

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气体运移速率的现场实例

国外油田工程 2002年第5期18卷 29-30,41页

作者： R.d.Grace jerald L.L.Shursen 刘雪芹谷玉堂大庆石油管理局钻井研究所

由 5个油田的现场实例说明 ,最近的研究向传统的气体流入 (气体侵入井内 )概念提出了挑战。以往现场人员一直使用“经验法则” ,即气体以 10 0 0ft h的速率运移。但现场实例表明 ,气体可能移动 ,也可能不移动 ,其运移速率受多种因素影响。

关键词：油田气体侵入运移速率现场实例