PADRAM: Parametric Design and Rapid Meshing System for Complex Turbomachinery Configurations

2012 ◽  
Author(s):  
Andrea Milli ◽  
Shahrokh Shahpar
Keyword(s):  
Parametric Design ◽  
Numerical Models ◽  
Geometrical Features ◽  
Key Factor ◽  
Structured Meshes ◽  
Feature Based ◽  
Unstructured Meshing ◽  
Structured Approach ◽  
Meshing Process ◽  
Made In

This paper reports the progress made in a parametric design and rapid meshing system (PADRAM) developed under two recent UK national sponsored research programs. PADRAM is designed to parametrically change the blade geometry and rapidly generate body-conformal high-quality viscous meshes. This allows speeding up the CFD loop by making the meshing process fully automatic on the basis of pre-designed templates. The geometry parameterisation is done within the mesh generator, making its integration within the optimisation loop straightforward. The paper presents examples that demonstrate how incorporating real geometry features into PADRAM is fundamental to achieve numerical models closer to reality. This is key factor in trusting the CFD solution and making use of it to further improve current designs. It also shows that feature-based structured mesh is good for cases that need to be repeatable across sites and teams, where consistency of the mesh is crucial and quick answers required to cope with tight project deadlines. The incorporation of additional complex geometrical features limits the applicability of the template structured approach and can be sometimes at the expense of mesh quality. In this regard, novel unstructured meshing technologies have been developed and implemented into PADRAM in order to deal with non standard and complex configurations. Two of these methods are presented in this paper (i.e., Zipper Layer and Delaunay Cavity). The paper shows how these can be used to paste together various multi-block structured meshes, hence providing the most suitable meshing topology to be used for each component separately. This makes the PADRAM code a unique meshing tool, able to combine the advantages of the template-topology approach to the flexibility of fully unstructured meshes. A number of supportive examples is reported in the paper.

On modelling physical systems with stochastic models: diffusion versus Lévy processes

2008 ◽  
Vol 366 (1875) ◽  
pp. 2455-2474 ◽  
Author(s):  
Cécile Penland ◽  
Brian D Ewald
Keyword(s):  
Differential Equations ◽  
Stochastic Models ◽  
Lévy Processes ◽  
Numerical Models ◽  
Gaussian White Noise ◽  
Levy Processes ◽  
Physical Systems ◽  
Random Forcing ◽  
Weather And Climate ◽  
Made In

Stochastic descriptions of multiscale interactions are more and more frequently found in numerical models of weather and climate. These descriptions are often made in terms of differential equations with random forcing components. In this article, we review the basic properties of stochastic differential equations driven by classical Gaussian white noise and compare with systems described by stable Lévy processes. We also discuss aspects of numerically generating these processes.

scholarly journals Diagnosis and Therapeutic Management of Liver Fibrosis by microRNA

2021 ◽  
Vol 22 (15) ◽  
pp. 8139
Author(s):  
Tomoko Tadokoro ◽  
Asahiro Morishita ◽  
Tsutomu Masaki
Keyword(s):  
Liver Fibrosis ◽  
Viral Infections ◽  
Primary Biliary Cholangitis ◽  
Medical Need ◽  
Key Factor ◽  
Complications Of Cirrhosis ◽  
And Control ◽  
Functional Rnas ◽  
Remarkable Progress ◽  
Made In

Remarkable progress has been made in the treatment and control of hepatitis B and C viral infections. However, fundamental treatments for diseases in which liver fibrosis is a key factor, such as cirrhosis, alcoholic/nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis, are still under development and remain an unmet medical need. To solve this problem, it is essential to elucidate the pathogenesis of liver fibrosis in detail from a molecular and cellular perspective and to develop targeted therapeutic agents based on this information. Recently, microRNAs (miRNAs), functional RNAs of 22 nucleotides, have been shown to be involved in the pathogenesis of liver fibrosis. In addition, extracellular vesicles called “exosomes” have been attracting attention, and research is being conducted to establish noninvasive and extremely sensitive biomarkers using miRNAs in exosomes. In this review, we summarize miRNAs directly involved in liver fibrosis, miRNAs associated with diseases leading to liver fibrosis, and miRNAs related to complications of cirrhosis. We will also discuss the efficacy of each miRNA as a biomarker of liver fibrosis and pathology, and its potential application as a therapeutic agent.

Consistency Management in Feature-Based Parametric Design

1995 ◽  
Author(s):  
Ana Sofia Vieira
Keyword(s):  
Parametric Design ◽  
Automatic Generation ◽  
Fundamental Principle ◽  
Consistency Management ◽  
Semantic Constraints ◽  
Evaluation Time ◽  
Feature Based ◽  
Consistent Feature ◽  
Semantic Correctness ◽  
Definition Of

Abstract One of the main problems to be solved in design-by-features is to preserve the semantic correctness of feature-based models. Currently, feature-based parametric design (FbPD) is being used as one of the most powerful approaches for solving this problem. In this paper, a fundamental principle of this approach is introduced. Three aspects stated, are: FbPD deals with functional design primitives, it solves the automatic generation of model variations, and it offers the basis for the development of a mechanism to check the semantic correctness of feature-based models. Several concepts for the definition of semantic constraints are presented. They instigate the classification of semantic constraints in four different categories, based on the constraint evaluation-time, purpose, behaviour, and representation. Sinfonia, a system for feature-based parametric design, is presented as a testbed environment for design-by-features applications. One of its modules, the Consistency Handler, uses the constraint concepts introduced in order to preserve the semantic consistency of the models. Several examples illustrate the different types of constraints. In addition, an algorithm applied for the process of a consistent feature modification is presented.

In Implementing a Metal 3D AM Machine

2018 ◽  
Vol 786 ◽  
pp. 356-363
Author(s):  
Tero Jokelainen ◽  
Kimmo Mäkelä ◽  
Aappo Mustakangas ◽  
Jari Mäkelä ◽  
Kari Mäntyjärvi
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Dimensional Accuracy ◽  
Acceptance Test ◽  
Aisi 316L ◽  
Laser Melting ◽  
Geometrical Accuracy ◽  
Machine Performance ◽  
Geometrical Features ◽  
Made In

Additive Manufacturing (AM) does not yet have a standardized way to measure performance. Here a AM machines dimensional accuracy is measured trough acceptance test (AT) and AM machines capability is tested trough test parts. Test parts are created with specific geometrical features using a 3D AM machine. Performance of the machine is then evaluated trough accuracy of test parts geometry. AM machine here uses selective laser melting (SLM) process. This machine has done Factory acceptance test (FAT) to ascertain this machine ́s geometrical accuracy with material AISI 316L. Manufacturer promises accuracy of ±0.05 mm. These parts are used as comparison to AT parts made in this study. After installation two AT parts are manufactured with AM machine. One with AISI 316L and one AlSi10Mg. Dimensional accuracy of geometrical features on these parts are then compared to FAT part and to one another. Machines capability is measured trough two test parts done with material AlSi10Mg. Two of the test parts are done at the same time using same model as the FAT. Parts are printed without supports and with features facing same directions. Features of these parts were then evaluated. Another test to find out AM machines capability was to create part consisting of pipes doing 90˚ angle resulting in horizontal and vertical holes. Dimensional accuracy and circularity of holes was measured. Through these tests machines capability is benchmarked.

Feature Based Parametric Design of Piston Reliability

2014 ◽  
Vol 511-512 ◽  
pp. 573-577
Author(s):  
Feng Jun Wang
Keyword(s):  
Boundary Conditions ◽  
Detailed Analysis ◽  
Parametric Design ◽  
Parametric Methods ◽  
Feature Size ◽  
Thermal Boundary Conditions ◽  
Engine Piston ◽  
Feature Based ◽  
Reserve Strength

In this paper the characteristics of the piston features for classification and feature library; at the same time the feature size and the feature existence parametric methods are discussed in detail. In a detailed analysis of the engine piston load based on, forward piston mechanical,thermal boundary conditions, forward piston mechanical, thermal boundary conditions, the results show that the original piston has a larger reserve strength, this research provided probility for the further optimization.

scholarly journals Wave Climate at Shallow Waters along the Abu Dhabi Coast

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 985 ◽  
Author(s):  
Waleed Hamza ◽  
Letizia Lusito ◽  
Francesco Ligorio ◽  
Giuseppe Tomasicchio ◽  
Felice D’Alessandro
Keyword(s):  
Shallow Water ◽  
Numerical Models ◽  
Grid Point ◽  
Arabian Gulf ◽  
Acoustic Doppler Current Profiler ◽  
Wave Climate ◽  
Abu Dhabi ◽  
Water Conditions ◽  
Key Factor ◽  
Offshore Wave

High-resolution, reliable global atmospheric and oceanic numerical models can represent a key factor in designing a coastal intervention. At the present, two main centers have the capabilities to produce them: the National Oceanic and Atmospheric Administration (NOAA) in the U.S.A. and the European Centre for Medium-Range Weather Forecasts (ECMWF). The NOAA and ECMWF wave models are developed, in particular, for different water regions: deep, intermediate, and shallow water regions using different types of spatial and temporal grids. Recently, in the Arabian Gulf (also named Persian Gulf), the Abu Dhabi Municipality (ADM) installed an ADCP (Acoustic Doppler Current Profiler) to observe the atmospheric and oceanographic conditions (water level, significant wave height, peak wave period, water temperature, and wind speed and direction) at 6 m water depth, in the vicinity of the shoreline of the Saadiyat beach. Courtesy of Abu Dhabi Municipality, this observations dataset is available; the recorded data span the period from June 2015 to January 2018 (included), with a time resolution of 10 min and 30 min for the atmospheric and oceanographic variables, respectively. At the ADCP deployment location (ADMins), the wave climate has been determined using wave propagation of the NOAA offshore wave dataset by means of the Simulating WAves Nearshore (SWAN) numerical model, the NOAA and ECMWF wave datasets at the closest grid point in shallow water conditions, and the SPM ’84 hindcasting method with the NOAA wind dataset used as input. It is shown that the best agreement with the observed wave climate is obtained using the SPM ’84 hindcasting method for the shallow water conditions.

scholarly journals Doeltreffende keuringsonderhoude: Die taak van lynbestuur

1982 ◽  
Vol 13 (4) ◽  
pp. 197-204
Author(s):  
David Tromp
Keyword(s):  
Risky Decision ◽  
Selection Interview ◽  
Selection Interviews ◽  
Effective Selection ◽  
Negative Effect ◽  
Selection Decision ◽  
Main Components ◽  
Line Manager ◽  
Structured Approach ◽  
Made In

Effective selection interviews: The task of line management The selection interview still remains one of the most important and most commonly used selection techniques. During their formal training personnel officials are normally taught how to conduct selection interviews in a professional and effective way. However, the final responsibility for the selection decision still rests with the line manager but he often lacks the skills necessary to conduct a good selection interview. The result of this is that a highly intuitive and risky decision is taken. In this article the most important errors which interviewers make, are discussed. These errors relate in the first instance to the way in which selection interviews are conducted and the resulting shortcomings in communication which have a negative effect on the availability of the information required for decision-making. Secondly, errors are often made in respect of the interpretation and evaluation of this information. A procedure for eliminating these errors is proposed of which the main components are a semi-structured approach and the use of an interview appraisal form based on the prior identification of the required behavioural dimensions.

CONSERVATION AGRICULTURE IN THE INDOGANGETIC PLAINS OF INDIA: PAST, PRESENT AND FUTURE

2017 ◽  
Vol 55 (2) ◽  
pp. 339-357 ◽  
Author(s):  
PETER HOBBS ◽  
RAJ GUPTA ◽  
RAJ KUMAR JAT ◽  
R. K. MALIK
Keyword(s):  
Management Practices ◽  
New Technology ◽  
Conservation Agriculture ◽  
Gangetic Plains ◽  
Farmer Adoption ◽  
Key Factor ◽  
Complex Technology ◽  
Use Efficiency ◽  
On Farm ◽  
Made In

SUMMARYThis paper follows the progress made in India for research and farmer adoption of conservation agriculture (CA) since the publication of Erenstein (2012), who contested the idea that zero-till (ZT) establishment of wheat in rice–wheat systems could be further developed into full CA systems. Data presented in this paper show that research has successfully found solutions for both the wheat and rice phases of the rice–wheat systems of the Indo-Gangetic Plains (IGP) in the past 8 years. It shows that by finding solutions in both the rice and wheat phases, yields, water use efficiency and profits increased, while labour needs reduced. Indian scientists have also confirmed these benefits in participatory on-farm research in various locations, both east and west regions of the IGP. Farmers see for themselves through experimentation that they get higher yields with less cost and with more efficient use of inputs and water. A key factor has been the development of improved seed drills with the help of Indian private sector manufacturers of agricultural equipment. Indian scientists have also successfully conducted CA research on several other crops and in other regions besides the IGP. The paper shows that it is better to introduce parts of the CA management practices in a step-wise fashion first, rather than introducing the entire package at once since farmers first have to test and evaluate a new technology to understand how it benefits them personally before they will adopt it. The paper concludes that in the rice–wheat systems of South Asia, adoption of CA is indeed possible to achieve although it is still a work in progress. CA is a complex technology package and it takes time to overcome all of the contested issues mentioned in Erenstein (2012).

scholarly journals Plane trusses optimization by means of parametric design and genetic algorithms applying visual programming

2019 ◽  
Vol 20 (4) ◽  
pp. 1-10
Author(s):  
Hugo Félix Begliardo Olivero ◽  
Matías Bonelli Hernández
Keyword(s):  
Professional Practice ◽  
Computer Technology ◽  
Structural Engineering ◽  
Parametric Design ◽  
Visual Programming ◽  
Environmental Benefits ◽  
Engineering Practice ◽  
Additional Contribution ◽  
Structural Engineers ◽  
Made In

The optimization of structures is a wished goal, but it is not always achieved in engineering practice, due to either the large additional effort that it demands or the lack of necessary resources to carry it out. Structural engineers usually use batch procedures, consisting of utilizing the software, in which data are input, running the analysis and evaluating the results, along which it is decided whether the design is accepted or modifications must be made, in which case the process is repeated again. The consequence of this is that the final result, normally, will always be improvable. For that reason, the field of optimization has usually been reserved to the academia. The new currents of structural engineering seek optimization by means of parametric design and evolutionary computing. As an additional contribution to the use of these resources, the objective of this work is to present an algorithm developed through visual programming for sizing, shape and topology optimization of plane trusses of the classic Howe, Pratt or Warren typologies, and to highlight the advantages that the use of this resource provides for the professional work of structural engineers, since it allows them to develop their own algorithms without the need of previous knowledge of programming, and to achieve economic and environmental benefits from saving materials. All this configures a clear transfer of the advances of computer technology to professional practice, extending the frontiers of the academic sphere. As an example of application, a truss analyzed by traditional methods, without optimizing, and the same truss optimized with the aforementioned algorithm, are compared.

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