Pelletization Quality Simulation for Operation Uncertainty of Die-Plate Based on Liquid-Solid-Liquid Coupling Model

2012 ◽  
Vol 557-559 ◽  
pp. 2266-2273 ◽  
Author(s):  
Xiao Feng Liu ◽  
Fu Qiao Liu ◽  
Bao Hai Yu ◽  
Chao Bi ◽  
Bing Zhang
Keyword(s):  
Large Scale ◽  
Flow Distribution ◽  
Coupling Model ◽  
Evaluation Framework ◽  
Mechanism Analysis ◽  
Operation Condition ◽  
Fem Method ◽  
Simulation And Evaluation ◽  
Solid Liquid ◽  
The Impact

As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization quality. Flow fluctuation of extruder and die-hole blocking can be summarized as two uncertainties for pelletization quality problem. A Liquid-Solid-Liquid coupling FEM method is presented to simulate factors of temperature distribution, flow distribution and flow rate control. Based on the calculations and mechanism analysis, pelletization quality degree and assessment framework are designed and calculated to analyze the impact of operation uncertainties to final product. With the simulation and evaluation framework, control methods for pelletization quality are discussed for Die-plate design and operation condition settings.

Constraining the model representation of the aerosol life cycle in relation to sources and sinks.

2020 ◽  
Author(s):  
Paul Kim ◽  
Daniel Partridge ◽  
James Haywood
Keyword(s):  
Climate Change ◽  
Life Cycle ◽  
Large Scale ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Evaluation Framework ◽  
Microphysical Properties ◽  
The Impact ◽  
Source And Sink

<p>Global climate model (GCM) ensembles still produce a significant spread of estimates for the future of climate change which hinders our ability to influence policymakers. The range of these estimates can only partly be explained by structural differences and varying choice of parameterisation schemes between GCMs. GCM representation of cloud and aerosol processes, more specifically aerosol microphysical properties, remain a key source of uncertainty contributing to the wide spread of climate change estimates. The radiative effect of aerosol is directly linked to the microphysical properties and these are in turn controlled by aerosol source and sink processes during transport as well as meteorological conditions.</p><p>A Lagrangian, trajectory-based GCM evaluation framework, using spatially and temporally collocated aerosol diagnostics, has been applied to over a dozen GCMs via the AeroCom initiative. This framework is designed to isolate the source and sink processes that occur during the aerosol life cycle in order to improve the understanding of the impact of these processes on the simulated aerosol burden. Measurement station observations linked to reanalysis trajectories are then used to evaluate each GCM with respect to a quasi-observational standard to assess GCM skill. The AeroCom trajectory experiment specifies strict guidelines for modelling groups; all simulations have wind fields nudged to ERA-Interim reanalysis and all simulations use emissions from the same inventories. This ensures that the discrepancies between GCM parameterisations are emphasised and differences due to large scale transport patterns, emissions and other external factors are minimised.</p><p>Preliminary results from the AeroCom trajectory experiment will be presented and discussed, some of which are summarised now. A comparison of GCM aerosol particle number size distributions against observations made by measurement stations in different environments will be shown, highlighting the difficulties that GCMs have at reproducing observed aerosol concentrations across all size ranges in pristine environments. The impact of precipitation during transport on aerosol microphysical properties in each GCM will be shown and the implications this has on resulting aerosol forcing estimates will be discussed. Results demonstrating the trajectory collocation framework will highlight its ability to give more accurate estimates of the key aerosol sources in GCMs and the importance of these sources in influencing modelled aerosol-cloud effects. In summary, it will be shown that this analysis approach enables us to better understand the drivers behind inter-model and model-observation discrepancies.</p>

scholarly journals A Large-Scale Pseudoword-Based Evaluation Framework for State-of-the-Art Word Sense Disambiguation

2014 ◽  
Vol 40 (4) ◽  
pp. 837-881 ◽  
Author(s):  
Mohammad Taher Pilehvar ◽  
Roberto Navigli
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Word Sense Disambiguation ◽  
Evaluation Framework ◽  
Small Scale ◽  
Word Sense ◽  
Knowledge Based ◽  
Depth Analysis ◽  
Sense Disambiguation ◽  
The Impact

The evaluation of several tasks in lexical semantics is often limited by the lack of large amounts of manual annotations, not only for training purposes, but also for testing purposes. Word Sense Disambiguation (WSD) is a case in point, as hand-labeled datasets are particularly hard and time-consuming to create. Consequently, evaluations tend to be performed on a small scale, which does not allow for in-depth analysis of the factors that determine a systems' performance. In this paper we address this issue by means of a realistic simulation of large-scale evaluation for the WSD task. We do this by providing two main contributions: First, we put forward two novel approaches to the wide-coverage generation of semantically aware pseudowords (i.e., artificial words capable of modeling real polysemous words); second, we leverage the most suitable type of pseudoword to create large pseudosense-annotated corpora, which enable a large-scale experimental framework for the comparison of state-of-the-art supervised and knowledge-based algorithms. Using this framework, we study the impact of supervision and knowledge on the two major disambiguation paradigms and perform an in-depth analysis of the factors which affect their performance.

scholarly journals Dynamic Response Analysis of Retaining Dam under the Impact of Solid-Liquid Two-Phase Debris Flow Based on the Coupled SPH-DEM-FEM Method

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Bailong Li ◽  
Changming Wang ◽  
Yanying Li ◽  
Yiao Liu ◽  
Nan Jiang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Debris Flow ◽  
Impact Force ◽  
Time History ◽  
Impact Behavior ◽  
Response Analysis ◽  
Two Phase ◽  
Fem Method ◽  
Solid Liquid ◽  
The Impact

Based on the coupled SPH-DEM-FEM numerical method, this paper analyzes the dynamic interaction of solid debris flow particle-liquid debris flow slurry-retaining dam in order to explore the dynamic response of retaining dam under the impact of the solid-liquid two-phase debris flow and delves into the process of the debris flow impact on the dam, the impact force of debris flow, and the elastic-plastic time-history characteristics of the dam under different slopes of trapezoidal grooves. The calculation results show that the coupled SPH-DEM-FEM method can vividly simulate the impact behavior of the solid-liquid two-phase debris flow on the dam, reproduce the impact, climbing, and siltation in the process of the debris flow impact; the dynamic time-history curve of the retaining dam is consistent with the law of the literature, and the result of the debris flow impact force obtained is close to that of the empirical formula. Moreover, this paper studies the impact force distribution of the debris flow impact process. The results have a certain reference value for the study of the dynamic response of the retaining dam under the impact of the solid-liquid two-phase debris flow and the engineering design of the debris flow-retaining dam.

scholarly journals The Influence of Decentralized Wind Power on the Characteristics of Distribution Network

2021 ◽  
Vol 261 ◽  
pp. 01037
Author(s):  
Ruomeng Jiang
Keyword(s):  
Wind Power ◽  
Power Flow ◽  
Large Scale ◽  
Power Grid ◽  
Distribution Network ◽  
Flow Distribution ◽  
Voltage Level ◽  
Negative Impacts ◽  
The Impact ◽  
Planning And Operation

This paper expounds the influence of decentralized wind power on the characteristics of distribution network. Through analysis, it can be concluded that after installing an appropriate amount of decentralized wind power, the voltage level of load bus can be improved. The power flow distribution will be changed, and the network loss of the power grid will be reduced. The decentralized wind power has also brought about negative impacts, such as voltage flicker and harmonics, the impact on the scope and direction of protection of relay protection, and greater uncertainty in the planning and operation of regional power grid. The analysis above provides some theoretical guidance for the large-scale development of decentralized wind power in the future.

Fault Mechanism Analysis and Characteristic Extraction for Multi-Disc Clutch

2014 ◽  
Vol 526 ◽  
pp. 155-163
Author(s):  
Man Chen ◽  
He Yan Li ◽  
Biao Ma
Keyword(s):  
High Frequency ◽  
Initial Phase ◽  
Friction Pair ◽  
Vibration Signal ◽  
Coupling Model ◽  
Dynamics Simulation ◽  
Mechanism Analysis ◽  
The Difference ◽  
Vibration Signal Analysis ◽  
The Impact

The thermo-elastic coupling model of clutch friction pair is established by the thermoelastic instability theory to acquire the basic process of friction disc warp due to hot agglomeration; according to this process, thought of reflecting initial phase clutch fault by observing the partial deformation generated by hot spots is proposed in this paper. And based on this thought, the multi-disc clutch dynamics simulation model is established to acquire the dynamic characteristics existing on the friction pair when tiny deformation happens; according to vibration characteristics of this characteristics and the feature that the interference noise of the high frequency section of the transmission system is comparatively light, and based on the analysis on the difference of frequency spectrum of the high frequency section before and after shifting gears, a new kind of initial phase multi-disc clutch fault diagnosing method based on vibration signal analysis is proposed. The test results further prove that, this method can be used to extract the impact vibration generated by tiny deformation happened on the friction pair, and is hopeful to be used in the practical engineering of initial phase multi-disc clutch fault diagnosing.

Using rapid evaluation methods to assess service delivery changes: Lessons learned for evaluation practice during the COVID-19 pandemic

2022 ◽  
pp. 1035719X2110576
Author(s):  
Milbert Gawaya ◽  
Desiree Terrill ◽  
Eleanor Williams
Keyword(s):  
Service Delivery ◽  
Large Scale ◽  
Evaluation Method ◽  
Evaluation Methods ◽  
Lessons Learned ◽  
Evaluation Framework ◽  
Rapid Evaluation ◽  
Evaluation Approach ◽  
Response Planning ◽  
The Impact

The COVID-19 pandemic required large-scale service delivery changes for government, and provided the opportunity for evaluators to step up and support decision makers to understand the impact of these changes. Rapid evaluation methods (REM) provide a pragmatic approach for generating timely information for evidence-based policy and decision-making. Grounded in developmental and utilisation-focused evaluation theory, REM incorporates a team-based, mixed methods design, executed over a 6–8-week period. Customised rubrics were used to rigorously assess effectiveness and scalability of practice changes to inform COVID-19 response planning. REM is an alternative approach to full-scale evaluation models frequently implemented to assess policies and programs. Adapted use of REM suggests that meaningful insights can be gained through use of smaller scale evaluations. This article shares lessons learned from a novel rapid evaluation method applied in the context of the COVID-19 pandemic. The rapid evaluation approach was implemented to provide real-time insights and evaluative conclusions for 15 program and practice adaptations across Victorian health and human service settings. The article shares insights about the practical applicability of balancing rigour and timeliness when implementing a rapid evaluation, and strengths and limitations of working within a fast-paced evaluation framework. Findings can inform evaluative practice in resource and time-limited settings.

Advances in airlift reactors: modified design and optimization of operation conditions

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
Tao Zhang ◽  
Chaohai We ◽  
Yuan Ren ◽  
Chunhua Feng ◽  
Haizhen Wu
Keyword(s):  
Large Scale ◽  
Performance Enhancement ◽  
Scale Up ◽  
Elevated Pressure ◽  
Industrial Applications ◽  
Operation Condition ◽  
Design And Optimization ◽  
Operation Conditions ◽  
Condition Optimization ◽  
The Impact

AbstractAirlift reactor (ALR) is a promising multiphase reactor for industrial applications. Abundant reports about modifications of the conventional ALR and optimization of their operation conditions for the purpose of performance enhancement have been accumulated in literatures, demanding a review paper to summarize the reactor design modifications and operation condition optimization of the ALR. In this review, the published research findings and results have been summarized. The basic concepts including the ALRs’ conventional design, classification, principles of operation, and characteristic parameters have been analyzed and systematically organized. The updated advances in the ALR design modifications have been reported. In particular, the concepts of the “groveled ALR” solving the scaling up problem in wastewater treatment, large-scale application, and the ALR with the cross-shaped geometry modifier stabilizing and strengthening the reactor were considered. Also, new operation modes and optimal conditions for enhancing the performance of the ALR have also been summed up. Except for conventional gas-driven methods, new driven methods for the ALR, such as mixture emission of the gas and the liquid and gas-inducing impeller, have been introduced. Optimization of operation conditions for the ALR includes varying position of the gas spargers, utilizing elevated pressure reactor, and exploring the impact of operation parameters, such as superficial gas velocity, static liquid level, and fluid properties. Comparisons between conventional ALRs and the modified systems are carried out paying attention to analogies, similarities, and differences. Most of the documented research results are obtained for various reactor designs at a laboratory scale; studies at pilot and full scale are still insufficient, which indicates that universal scale up design rules permitting the ALR design with a high confidence are required.

scholarly journals Can the New Subway Line Openings Mitigate PM10 Concentration? Evidence from Chinese Cities Based on the PSM-DID Method

2020 ◽  
Vol 17 (13) ◽  
pp. 4638
Author(s):  
Ying Wang ◽  
Jing Tao ◽  
Rong Wang ◽  
Chuanmin Mi
Keyword(s):  
Air Quality ◽  
Treatment Effect ◽  
Large Scale ◽  
Time Windows ◽  
Pm10 Concentration ◽  
Mechanism Analysis ◽  
Short Term ◽  
Concentration Data ◽  
Short Term Treatment ◽  
The Impact

The large-scale construction of subway systems, which is viewed as one of the potential measures to mitigate traffic congestion and its resulting air pollution and health impact, is taking place in major cities throughout China. However, the literature on the impact of the new subway line openings on particulate matter with a diameter less than 10 µm (PM10) at the city level is scarce. Employing the Propensity Score Matching–Difference-in-differences method, this paper examines the effect of the new subway line openings on air quality in terms of PM10 in China, using the daily PM10 concentration data from January 2014 to December 2017. Our finding shows that the short-term treatment effect on PM10 is more controversial. Furthermore, for different time windows, the result confirms an increase in PM10 pollution during the short term, while the subway line openings improve air quality in the longer term. In addition, we find that the treatment effect results in high PM10 pollution for cities with 1–2 million people, while it improves air quality for cities with over 2 million people. Moreover, for cities with varying levels of GDP, there is evidence of a reduction in PM10 after the subway line openings. Mechanism analysis supports the conclusion that the PM10 reduction originated from substituting the subway for driving.

Impact of COVID-19 on Nuclear Medicine in Germany, Austria and Switzerland: An International Survey in April 2020

2020 ◽  
Vol 59 (04) ◽  
pp. 294-299 ◽  
Author(s):  
Lutz S. Freudenberg ◽  
Ulf Dittmer ◽  
Ken Herrmann
Keyword(s):  
Nuclear Medicine ◽  
Health Systems ◽  
Personal Protective Equipment ◽  
Large Scale ◽  
Diagnostic Procedures ◽  
Protective Equipment ◽  
Current Crisis ◽  
Web Based ◽  
Public Versus Private ◽  
The Impact

Abstract Introduction Preparations of health systems to accommodate large number of severely ill COVID-19 patients in March/April 2020 has a significant impact on nuclear medicine departments. Materials and Methods A web-based questionnaire was designed to differentiate the impact of the pandemic on inpatient and outpatient nuclear medicine operations and on public versus private health systems, respectively. Questions were addressing the following issues: impact on nuclear medicine diagnostics and therapy, use of recommendations, personal protective equipment, and organizational adaptations. The survey was available for 6 days and closed on April 20, 2020. Results 113 complete responses were recorded. Nearly all participants (97 %) report a decline of nuclear medicine diagnostic procedures. The mean reduction in the last three weeks for PET/CT, scintigraphies of bone, myocardium, lung thyroid, sentinel lymph-node are –14.4 %, –47.2 %, –47.5 %, –40.7 %, –58.4 %, and –25.2 % respectively. Furthermore, 76 % of the participants report a reduction in therapies especially for benign thyroid disease (-41.8 %) and radiosynoviorthesis (–53.8 %) while tumor therapies remained mainly stable. 48 % of the participants report a shortage of personal protective equipment. Conclusions Nuclear medicine services are notably reduced 3 weeks after the SARS-CoV-2 pandemic reached Germany, Austria and Switzerland on a large scale. We must be aware that the current crisis will also have a significant economic impact on the healthcare system. As the survey cannot adapt to daily dynamic changes in priorities, it serves as a first snapshot requiring follow-up studies and comparisons with other countries and regions.

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