scholarly journals ONE- AND TWO-NODE HYBRID LEAKAGE-CORRECTED 3-D CMFD ALGORITHM FOR FAST AND ACCURATE PIN-WISE PWR ANALYSIS

2021 ◽  
Vol 247 ◽  
pp. 02022
Author(s):  
Jaeha Kim ◽  
Hwanyeal Yu ◽  
Yonghee Kim
Keyword(s):  
Parallel Computing ◽  
Iterative Scheme ◽  
Flux Ratio ◽  
Correction Method ◽  
Core Analysis ◽  
Coarse Mesh ◽  
Benchmark Problem ◽  
Sph Method ◽  
Step Procedure ◽  
The One

The HCMFD (Hybrid Coarse-Mesh Finite Difference) with GPS (GET Plus SPH) method and its 3-D application are investigated in this paper. In the HCMFD algorithm, a parallel computing for a pin-by-pin core calculation can be performed very effectively with a non-linear local-global iterative scheme. For an effective parallel computing, the one-node CMFD is used to solve a global eigenvalue problem. The conventional two-node CMFD is used for solving local fixed source problems with incoming current boundary conditions. The GPS method is a leakage correction method to correct the pin-wise XSs of the conventional GET-based two-step procedure. In the GPS method, the XS-dependent SPH factors are parameterized as a function of the pin-wise albedo information, current-to-flux ratio (CFR). With updated XS-wise SPH factors, the pin-wise XSs are corrected in order to improve the accuracy of the conventional two-step core analysis. The GPS method is implemented to an in-house pin-by-pin diffusion solver with the HCMFD algorithm to keep their strong points together. In this paper, several 3-D variant cores of KAIST-1A benchmark problem were chosen to demonstrate the combination of HCMFD and GPS (HCMFD-GPS) method.

scholarly journals A procedure for the introduction of leanness into a company

2021 ◽  
Author(s):  
Davorin Cimermančič ◽  
Janez Kušar ◽  
Tomaž Berlec
Keyword(s):  
Negative Impact ◽  
General Procedure ◽  
Portfolio Analysis ◽  
The Other ◽  
Business Operations ◽  
Step Procedure ◽  
The One ◽  
A Company

AbstractChanging a traditional company into a lean one is a very complex and time-consuming process that needs to be addressed in an appropriate way, otherwise the project of introduction of leanness into a company may fail on the one hand and even have a negative impact on business operations of the company on the other. When introducing a change, a step-by-step procedure leading to a progress may be of great help. The paper outlines a general procedure of leanness, an important part of which is a lean agent. A portfolio analysis is also used as a measure of leanness or as an indicator of the desired direction. The applied working methods were mainly active workshops and interviews with employees. The procedure has been tested on an example of a Slovene company; first, the existing situation is outlined, then the leanness steps taken according to the procedure and the final result after the first transition of the procedure.

scholarly journals Progress in the Smoothed Particle Hydrodynamics Method to Simulate and Post-process Numerical Simulations of Annular Airblast Atomizers

2020 ◽  
Vol 105 (4) ◽  
pp. 1119-1147
Author(s):  
G. Chaussonnet ◽  
T. Dauch ◽  
M. Keller ◽  
M. Okraschevski ◽  
C. Ates ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Flux Ratio ◽  
Liquid Sheet ◽  
Sph Method ◽  
Post Process ◽  
Finite Time Lyapunov Exponent ◽  
Fragmentation Spectrum ◽  
Particle Hydrodynamics ◽  
Primary Breakup ◽  
Smoothed Particle

AbstractThis paper illustrates recent progresses in the development of the smoothed particle hydrodynamics (SPH) method to simulate and post-process liquid spray generation. The simulation of a generic annular airblast atomizer is presented, in which a liquid sheet is fragmented by two concentric counter swirling air streams. The accent is put on how the SPH method can bridge the gap between the CAD geometry of a nozzle and its characterization, in terms of spray characteristics and dynamics. In addition, the Lagrangian nature of the SPH method allows to extract additional data to give further insight in the spraying process. First, the sequential breakup events can be tracked from one large liquid blob to very fine stable droplets. This is herein called the tree of fragmentation. From this tree of fragmentation, abstract quantities can be drawn such as the breakup activity and the fragmentation spectrum. Second, the Lagrangian coherent structures in the turbulent flow can be determined easily with the finite-time Lyapunov exponent (FTLE). The extraction of the FTLE is particularly feasible in the SPH framework. Finally, it is pointed out that there is no universal and ultimate non-dimensional number that can characterize airblast primary breakup. Depending on the field of interest, a non-dimensional number (e.g. Weber number) might be more appropriate than another one (e.g. momentum flux ratio) to characterize the regime, and vice versa.

scholarly journals Conditional Variance Forecasts for Long-Term Stock Returns

Risks ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 113 ◽  
Author(s):  
Enno Mammen ◽  
Jens Perch Nielsen ◽  
Michael Scholz ◽  
Stefan Sperlich
Keyword(s):  
Stock Returns ◽  
Conditional Variance ◽  
Price Ratio ◽  
Prediction Errors ◽  
Step Procedure ◽  
Short And Long Term ◽  
Smoothing Parameters ◽  
One Year ◽  
The One

In this paper, we apply machine learning to forecast the conditional variance of long-term stock returns measured in excess of different benchmarks, considering the short- and long-term interest rate, the earnings-by-price ratio, and the inflation rate. In particular, we apply in a two-step procedure a fully nonparametric local-linear smoother and choose the set of covariates as well as the smoothing parameters via cross-validation. We find that volatility forecastability is much less important at longer horizons regardless of the chosen model and that the homoscedastic historical average of the squared return prediction errors gives an adequate approximation of the unobserved realised conditional variance for both the one-year and five-year horizon.

scholarly journals A WCSPH Particle Shifting Strategy for Simulating Violent Free Surface Flows

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3189
Author(s):  
Abdelkader Krimi ◽  
Mojtaba Jandaghian ◽  
Ahmad Shakibaeinia
Keyword(s):  
Free Surface ◽  
Surface Region ◽  
Free Surface Flows ◽  
Sph Method ◽  
Surface Flows ◽  
Weakly Compressible ◽  
Shifting Strategy ◽  
Long Time ◽  
The One ◽  
Stability And Consistency

In this work, we develop an enhanced particle shifting strategy in the framework of weakly compressible δ+-SPH method. This technique can be considered as an extension of the so-called improved particle shifting technology (IPST) proposed by Wang et al. (2019). We introduce a new parameter named “ϕ” to the particle shifting formulation, on the one hand to reduce the effect of truncated kernel support on the formulation near the free surface region, on the other hand, to deal with the problem of poor estimation of free surface particles. We define a simple criterion based on the estimation of particle concentration to limit the error’s accumulation in time caused by the shifting in order to achieve a long time violent free surface flows simulation. We propose also an efficient and simple concept for free surface particles detection. A validation of accuracy, stability and consistency of the presented model was shown via several challenging benchmarks.

Femtosecond laser-processed staining microchip for one-step preparation of fluorescent DNA sample without loss of DNAs

2019 ◽  
Author(s):  
Yeongseok Jang ◽  
Hojun Shin ◽  
Jinmu Jung ◽  
Jonghyun Oh
Keyword(s):  
Femtosecond Laser ◽  
Performance Test ◽  
Staining Method ◽  
Laser System ◽  
Molecular Transport ◽  
Main Channel ◽  
Step Procedure ◽  
One Step ◽  
On Chip ◽  
The One

In this study, we propose a microchip that is sequentially capable of fluorescently staining and washing DNAs. The main advantage of this microchip is that it allows for one-step preparation of small amounts of solution without degrading microscopic bio-objects such as the DNAs, cells, and biomolecules to be stained. The microchip consists of two inlets, the main channel, staining zone, washing zone, and one outlet, and was processed using a femtosecond laser system. High molecular transport of rhodamine B to deionized water was observed in the performance test of the microchip. Results revealed that the one-step procedure of on-chip DNA staining and washing was excellent compared to the conventional staining method. The one-step preparation of stained and washed DNAs through the microchip will be useful for preparing small volumes of experimental samples.

scholarly journals Fourth-Order Deferred Correction Scheme for Solving Heat Conduction Problem

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
D. Yambangwai ◽  
N. P. Moshkin
Keyword(s):  
Fourth Order ◽  
Heat Conduction Problem ◽  
Correction Method ◽  
Dirichlet Boundary Conditions ◽  
Heat Conducting ◽  
One Dimensional ◽  
Deferred Correction ◽  
The Stability ◽  
The One ◽  
Nicolson Scheme

A deferred correction method is utilized to increase the order of spatial accuracy of the Crank-Nicolson scheme for the numerical solution of the one-dimensional heat equation. The fourth-order methods proposed are the easier development and can be solved by using Thomas algorithms. The stability analysis and numerical experiments have been limited to one-dimensional heat-conducting problems with Dirichlet boundary conditions and initial data.

scholarly journals Immediate Free Jejunum Transfer for Salvage Surgery of Gastric Tube Necrosis

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Hiroki Umezawa ◽  
Takeshi Matsutani ◽  
Rei Ogawa ◽  
Hiko Hyakusoku
Keyword(s):  
Gastric Tube ◽  
Salvage Surgery ◽  
Present Report ◽  
Cervical Esophageal Cancer ◽  
Two Stage ◽  
Immediate Reconstruction ◽  
Recipient Vessel ◽  
Primary Surgery ◽  
Step Procedure ◽  
The One

Gastric tube necrosis after esophagus cancer surgery is a rare but critical situation. Salvage reconstruction of the esophagus remains a challenging procedure for head and neck surgeons. Historically, surgeons have employed a two-stage salvage surgery consisting of debridement followed by reconstruction. While this procedure generates good results, the time to restart oral alimentation is long. The present report describes the case of a 62-year-old male who developed gastric tube necrosis 3 days after undergoing surgery for thoracic-cervical esophageal cancer and immediate reconstruction with the retrosternal gastric pullup technique. He was treated with debridement and simultaneous free jejunum transfer 4 days after the primary surgery. He was able to restart oral alimentation 10 days after the salvage surgery. This rapid return to oral alimentation is a major advantage of the one-stage immediate esophagus salvage reconstruction. Another advantage is the ease of the reconstructive procedure: the absence of scarring and prolonged inflammation, which are disadvantages of the two-stage procedure, meant that recipient vessel selection and anastomosis were uncomplicated. The one-step procedure may be particularly useful in cases where the inflammation is discovered early.

A heterogeneous coarse mesh solution for the 2-D NEA C5G7 mox benchmark problem

2004 ◽  
Vol 45 (2-4) ◽  
pp. 233-254 ◽  
Author(s):  
Benoit Forget ◽  
Farzad Rahnema ◽  
Scott W. Mosher
Keyword(s):  
Coarse Mesh ◽  
Benchmark Problem
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