Piston dynamics analysis considering skirt-liner dynamic clearance

2019 ◽  
Vol 233 (13) ◽  
pp. 3538-3553 ◽  
Author(s):  
Jingyi Tian ◽  
Huihua Feng ◽  
Yuanjie Feng ◽  
Zhengwei Yang ◽  
Chengjun Zhu ◽  
...  
Keyword(s):  
Simulation Model ◽  
High Frequency ◽  
Thermal Deformation ◽  
Structural Parameters ◽  
Accurate Determination ◽  
Low Noise ◽  
Dynamics Analysis ◽  
Piston Skirt ◽  
The Impact

Piston slap force is one of the main sources of mechanical engine noise. To obtain a more accurate determination of the piston slap force and minimize piston slap noise, a new simulation model that considers dynamic clearance of the piston skirt and liner has been established in this study. The skirt-liner dynamic clearance is caused mainly by the elastic deformation and thermal deformation of the piston. Comparing three different models, it was found that the impact of dynamic clearance on the piston slap force is reflected mainly in the medium-high frequency, which is the sensitive frequency of the slap noise. Therefore, it is necessary to consider dynamic clearance in the simulation model. In addition, the mechanisms behind the dynamic clearance effect on fluid lubrication, piston dynamics, and piston slap noise were observed. In particular, three typical structural parameters in piston dynamics (the piston pin offset, piston-liner clearance, and piston skirt profile) were studied. The analyses provide guidance for the design of low-noise engines.

scholarly journals Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Vol 12 (10) ◽  
pp. 5503-5517 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Sulfur Dioxide ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Layer Height ◽  
Learning Machine ◽  
The Impact ◽  
First Time ◽  
Better Than

Abstract. The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI.

scholarly journals Simulating pollutant transport over complex terrain: the hydrological component

2012 ◽  
Vol 10 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Constantina Mita ◽  
Nicolaos Catsaros
Keyword(s):  
Channel Flow ◽  
Accurate Determination ◽  
Ground Surface ◽  
Pollutant Transport ◽  
Surface Flow ◽  
Valuable Insight ◽  
Distributed Hydrological Model ◽  
Channel Network ◽  
The Impact

AbstractThe accurate determination of surface water flow pathways is of primary importance when assessing the impact of pollutant transport and watershed physical characteristics on overland and channel water quality. The mathematical description of hydrological processes over natural watersheds, requires a detailed representation of the topography, on which the accurate determination of overland and channel flow trajectories often poses difficulties. The hydrological component of the DELTA code aims to provide valuable insight into this direction by using the semi-irregular triangulated (semi-TIN) topography model DELTA/HYDRO for establishing surface flow paths that can represent reliably the natural characteristics of a watershed, addressing several major physical hydrodynamic processes. The validity of the generated paths is tested via the integration of a conventional distributed hydrological model by routing excess rainfall over ground surface and through a channel network to the watershed outlet, for a series of storm episodes on a small, but relatively complex watershed. The encouraging results obtained demonstrate the promising application potential of the model, which can be additionally complemented with a pollutant transport component to address the interactions of soluble chemicals between soil surface and overland/channel flow, in the context of a fully integrated model.

Determining FAC Degradation From NDE Data

2009 ◽  
Author(s):  
Harold M. Crockett ◽  
Jeffrey S. Horowitz
Keyword(s):  
Error Propagation ◽  
Power Plants ◽  
Degradation Mechanism ◽  
Accurate Determination ◽  
Wear Rates ◽  
Flow Acceleration ◽  
Inspection Data ◽  
Evaluation Approaches ◽  
The Impact

Flow-acceleration corrosion (FAC) is a degradation mechanism that impacts carbon steel piping components and equipment under conditions often found in both nuclear and fossil power plants. To deal with this type of degradation, many utilities have instituted inspection programs designed to discover dangerous situations well before failures occur. Inspections to determine FAC damage are normally done using the Ultrasonic Technique (UT) although other methods are also used. For large bore components, the most commonly used inspection approach is gridded UT measurements. Experience has shown that the amount of degradation that typically occurs between inspections is comparable to the uncertainty of the UT measurements. Thus, the accurate determination of the actual wear rates is difficult as the measurement uncertainties tend to cause over-stating the actual degradation. To deal with this problem, EPRI has developed a number of evaluation approaches for interpreting data from one inspection, from two sets of inspections and from more than two sets of inspections. The application of these methods to inspection data will be discussed demonstrating the performance of the different approaches. The impact of the error propagation on the accuracy of these methods and recommendations for different circumstances will be presented.

Improving quality of care and reducing costs with angiogenesis-specific imaging tests in metastatic breast cancer.

2012 ◽  
Vol 30 (34_suppl) ◽  
pp. 150-150
Author(s):  
Carolyn Bodnar ◽  
L. Clark Paramore ◽  
Kevin B. Knopf
Keyword(s):  
Breast Cancer ◽  
Quality Of Care ◽  
Metastatic Breast Cancer ◽  
Accurate Determination ◽  
Metastatic Breast ◽  
Base Case ◽  
Test Results ◽  
The Impact

150 Background: Anti-angiogenesis (AA) drugs (e.g., bevacizumab) are expensive and their clinical benefit in metastatic breast cancer (MBC) has been challenged. Healthcare reform and financial pressures prioritize programs which improve patient quality of care and reduce costs of unnecessary care. Angiogenesis-specific imaging tests (A-IT) under development have potential to offer earlier, accurate determination of response. For A-IT-identified responders, AA treatment would be continued. For patients identified as non-responders, futile AA treatment and associated toxicities can be avoided and alternative therapies initiated. Methods: A decision-tree model was developed to estimate the impact of A-IT from determination of AA therapy eligibility through to disease progression. Key decision nodes were presence/absence of A-IT (assessing change in biomarker expression across 2 PET/CT scans: at AA eligibility, then after one cycle of AA), A-IT sensitivity/specificity (SE/SP) and clinician adherence to test results (tied to belief that results are valid enough to stop AA therapy). Key model inputs (and base case values): 1) median time to progression (TTP) for current MBC patients on AA therapies (9.5 months); 2) median TTP for A-IT identified responders (13 months); 3) costs of bevacizumab, one cycle ($5,200); 4) percentage of AA patients with hemorrhage (4%); 5) costs of hemorrhaging, per event ($14,694); 6) per patient costs for A-IT ($6,000); 7) estimated SE/SP of A-IT – 95%/75%; and 8) clinician adherence to test results (75%). Results: Based on a cohort of 100 MBC patients, use of A-IT results in 29 patients avoiding futile AA therapy with a saving of $460,000, versus a scenario where A-IT was not used. One-way threshold sensitivity analysis shows A-IT is cost-saving if SP >62% or when clinician adherence is ≥63%; results are not sensitive to AA hemorrhage rate. Conclusions: Use of A-IT could improve quality of care by optimizing AA therapy, i.e., by identifying responders who will experience survival benefit and non-responders who can avoid futile therapy and toxicity risks. Significant cost savings may be possible as a result of early determination of response to AA drugs.

Defect concentration and Δn change in light- and elevated temperature- induced degradation

2021 ◽  
Author(s):  
Moonyong Kim ◽  
Matthew Wright ◽  
Daniel Chen ◽  
Catherine Chan ◽  
Alison Ciesla ◽  
...  
Keyword(s):  
Surface Passivation ◽  
Defect Density ◽  
Accurate Determination ◽  
Defect Concentration ◽  
Doping Density ◽  
Lifetime Analysis ◽  
Materials Used ◽  
New Formulation ◽  
The Impact

Abstract The wide variety of silicon materials used by various groups to investigate LeTID make it difficult to directly compare the defect concentrations (Nt) using the typical normalised defect density (NDD) metric. Here, we propose a new formulation for a relative defect concentration (β) as a correction for NDD that allows flexibility to perform lifetime analysis at arbitrary injection levels (Δn), away from the required ratio between Δn and the background doping density (Ndop) for NDD of Δn/N dop = 0.1. As such, β allows for a meaningful comparison of the maximum degradation extent between different samples in different studies and also gives a more accurate representative value to estimate the defect concentration. It also allows an extraction at the cross-over point in the undesirable presence of iron, or flexibility to reduce the impact of modulation in surface passivation. Although the accurate determination of β at a given Δn requires knowledge of the capture cross-section ratio (k), the injection-independent property of the β formulation allows a self-consistent determination of k. Experimental verification is also demonstrated for boron-oxygen related defects and LeTID defects, yielding k-values of 10.6 ± 3.2 and 30.7 ± 4.0, respectively, which are within the ranges reported in the literature. With this, when extracting the defect density at different Δn ranging between 1014 /cm3 to 1015 /cm3 with Ndop = 9.1 ×1015 /cm3, the error is less than 12% using β, allowing for a greatly improved understanding of the defect concentration in a material.

Determination of Propagation Rate Coefficients for Methyl and 2-Ethylhexyl Acrylate via High Frequency PLP−SEC under Consideration of the Impact of Chain Branching

2010 ◽  
Vol 43 (24) ◽  
pp. 10427-10434 ◽  
Author(s):  
Tanja Junkers ◽  
Maria Schneider-Baumann ◽  
Sandy S. P. Koo ◽  
Patrice Castignolles ◽  
Christopher Barner-Kowollik
Keyword(s):  
High Frequency ◽  
Propagation Rate ◽  
Rate Coefficients ◽  
Chain Branching ◽  
The Impact

Effect of PP-g-MAH on Properties of ABS/PP Blends

2015 ◽  
Vol 727-728 ◽  
pp. 313-317
Author(s):  
Hai Ling Li ◽  
Lai Xiang Zhang ◽  
Xiao Ling Ding
Keyword(s):  
Process Parameters ◽  
Deformation Temperature ◽  
Thermal Deformation ◽  
Performance Test ◽  
Process Performance ◽  
Mixed Design ◽  
Performance Impact ◽  
Pp Blends ◽  
The Impact

Research of ABS and PP were mixed design, preparation and formulation of gold for the production process, performance test. Discussed in PP - g - MAH as computerize of cases, in the process of ABS blended with PP, ABS/PP blend formulas and the determination of process parameters is analyzed. Through performance test and analysis different composition ratio of computerize on the ABS/PP alloy performance impact. Finally concluded that, in the ABS/PP/PP blend - g - MAH, when PP-g-MAH is 4, 16 for PP, the impact of the blend with good performance, thermal deformation temperature is increased.

scholarly journals Simulation of Intermittent Turning Processes

1991 ◽  
Vol 113 (3) ◽  
pp. 458-466 ◽  
Author(s):  
G. M. Zhang ◽  
S. Yerramareddy ◽  
S. M. Lee ◽  
S. C.-Y. Lu
Keyword(s):  
Simulation Model ◽  
Initial Value ◽  
Principle Of Superposition ◽  
Practical Applications ◽  
Vibratory Motion ◽  
Intermittent Turning ◽  
Experimental Findings ◽  
The Impact ◽  
Chip Load

A simulation model is developed to study the dynamic characteristics of intermittent turning operations. Factors such as chip load, free-vibration of the toolpost structure, and nonhomogeneous hardness distribution in the material being cut are incorporated in the model. The principle of superposition is used in the formulation of the simulation algorithm. The impact between the cutting tool and the workpiece at the start of every cutting period during machining is treated as an initial value problem. The simulation model provides a quantitative evaluation of the tool vibratory motion during the intermittent turning process. Study of the cutting dynamics based on the simulation results not only confirms the experimental findings, but also indicates that increasing the static stiffness of the toolpost structure is an effective approach to control the tool vibratory motion. The determination of probability of tool breakage under various spindle speed settings is presented as an example to demonstrate the practical applications of the simulation model developed in this work.

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