scholarly journals The Development of a Second-Generation of Controlled Diffusion Airfoils for Multistage Compressors

1985 ◽  
Author(s):  
R. F. Behlke
Keyword(s):  
Large Scale ◽  
First Generation ◽  
Second Generation ◽  
Flow Region ◽  
Operating Conditions ◽  
Design Model ◽  
Controlled Diffusion ◽  
Significant Performance ◽  
Multistage Compressors ◽  
High Mach

The evolution of Controlled Diffusion Airfoils is traced from inception of the theoretical design model to demonstration of significant performance gains at engine operating conditions in a multistage compressor rig. The proven aerodynamic benefits and versatility of first-generation Controlled Diffusion Airfoil blade elements are extended to the endwall flow region using an Integrated Core/Endwall Vortex design model to produce a new full span optimized second-generation Controlled Diffusion design. Highlighted are the essential roles of extensive cascade, low speed, large scale and high Mach number compressor rig testing in developing and substantiating the second generation Controlled Diffusion technology resulting in a 1.5% increase in efficiency and 30% increase in surge-free operation relative to first-generation Controlled Diffusion Airfoils.

The Development of a Second Generation of Controlled Diffusion Airfoils for Multistage Compressors

1986 ◽  
Vol 108 (1) ◽  
pp. 32-40 ◽  
Author(s):  
R. F. Behlke
Keyword(s):  
Large Scale ◽  
First Generation ◽  
Second Generation ◽  
Flow Region ◽  
Operating Conditions ◽  
Design Model ◽  
Controlled Diffusion ◽  
Percent Increase ◽  
Significant Performance ◽  
High Mach

The evolution of Controlled Diffusion Airfoils is traced from inception of the theoretical design model to demonstration of significant performance gains at engine operating conditions in a multistage compressor rig. The proven aerodynamic benefits and versatility of first-generation Controlled Diffusion Airfoil blade elements are extended to the endwall flow region using an Integrated Core/Endwall Vortex design model to produce a new full-span optimized second-generation Controlled Diffusion design. Highlighted are the essential roles of extensive cascade, low-speed, large-scale, and high Mach number compressor rig testing in developing and substantiating the second-generation Controlled Diffusion technology resulting in a 1.5 percent increase in efficiency and 30 percent increase in surge-free operation relative to first-generation Controlled Diffusion Airfoils.

Investigation of the Role of Droplet Transport in Mitigating Top of the Line Corrosion

CORROSION ◽  
10.5006/2764 ◽  
2018 ◽  
Vol 74 (8) ◽  
pp. 873-885
Author(s):  
Nicolas Jauseau ◽  
Fernando Farelas ◽  
Marc Singer ◽  
Srdjan Nešić
Keyword(s):  
Large Scale ◽  
Flow Region ◽  
Limited Range ◽  
Operating Conditions ◽  
Experimental Methodology ◽  
Liquid Droplets ◽  
Flow Loop ◽  
Droplet Entrainment ◽  
Droplet Transport ◽  
Large Scale Flow

The entrainment of liquid droplets, occurring in a limited range of gas and liquid flow conditions within the stratified flow region, could represent an effective way to transport a non-volatile liquid corrosion inhibitor through the gas phase and combat top of the line corrosion (TLC). However, such an approach is only viable if the inhibitor can reach the top of the pipe and deposit at a rate higher than the local rate of condensing water can dilute it. This work presents a combined modeling and experimental methodology to determine the onset of droplet entrainment from the bottom and deposition at the top of the line. A modeling approach predicting the droplet entrainment onset is proposed and validated against new multiphase flow data recorded in a large scale flow loop, at operating conditions similar to those encountered in gas-condensate production facilities. Additionally, TLC experiments were performed in the same flow loop under simulated water condensation conditions to measure the actual corrosion at different rates of inhibiting droplet deposition. The results confirm that the droplet entrainment/deposition can effectively mitigate TLC when operating parameters are accurately controlled.

A PERFORMANCE EVALUATION OF THE NEHALEM QUAD-CORE PROCESSOR FOR SCIENTIFIC COMPUTING

2008 ◽  
Vol 18 (04) ◽  
pp. 453-469 ◽  
Author(s):  
KEVIN J. BARKER ◽  
KEI DAVIS ◽  
ADOLFY HOISIE ◽  
DARREN J. KERBYSON ◽  
MIKE LANG ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Large Scale ◽  
Scientific Computing ◽  
First Generation ◽  
Second Generation ◽  
Building Blocks ◽  
Simultaneous Multithreading ◽  
Scientific Applications ◽  
Memory Controller ◽  
A Performance

In this work we present an initial performance evaluation of Intel's latest, second-generation quad-core processor, Nehalem, and provide a comparison to first-generation AMD and Intel quad-core processors Barcelona and Tigerton. Nehalem is the first Intel processor to implement a NUMA architecture incorporating QuickPath Interconnect for interconnecting processors within a node, and the first to incorporate an integrated memory controller. We evaluate the suitability of these processors in quad-socket compute nodes as building blocks for large-scale scientific computing clusters. Our analysis of intra-processor and intra-node scalability of microbenchmarks, and a range of large-scale scientific applications, indicates that quad-core processors can deliver an improvement in performance of up to 4x over a single core depending on the workload being processed. However, scalability can be less when considering a full node. We show that Nehalem outperforms Barcelona on memory-intensive codes by a factor of two for a Nehalem node with 8 cores and a Barcelona node containing 16 cores. Further optimizations are possible with Nehalem, including the use of Simultaneous Multithreading, which improves the performance of some applications by up to 50%.

scholarly journals Transitioning from a First Generation to Second Generation Large-Scale Agile Development Method: Towards Understanding Implications for Coordination

2020 ◽  
pp. 84-91
Author(s):  
Finn Olav Bjørnson ◽  
Torgeir Dingsøyr
Keyword(s):  
Large Scale ◽  
First Generation ◽  
Second Generation ◽  
Development Project ◽  
Agile Development ◽  
Public Organization ◽  
Longitudinal Case Study ◽  
Development Method ◽  
Development Methodology

Abstract This paper reports our initial findings from a longitudinal case study within a large development project in a public organization in Scandinavia. We focus on changes in coordination practices as the development project moved from a 1st to a 2nd generation large-scale agile development methodology. Building on four theories of coordination from different fields, we investigate how each theory illuminates our case and what insight they might provide. We find that two of the theories are well suited to characterizing each phase, providing answer to how coordination was done. While two other theories can provide answers to why these changes occurred.

Do remittances differ depending on migration pathway and length of stay?

2016 ◽  
Vol 1 (1) ◽  
pp. 105-118
Author(s):  
Anita Pugliese ◽  
Julie Ray ◽  
Neli Esipova
Keyword(s):  
Length Of Stay ◽  
First Generation ◽  
Second Generation ◽  
Global Analysis ◽  
Large Sample ◽  
Migration Pathway ◽  
First Generation Migrants ◽  
Second Generation Migrants

This paper reports the results from Gallup’s global analysis of the likelihood of first-generation migrants, second-generation migrants and the native-born to send financial help in the form of money or goods to others inside or outside their respective country of residence. The findings in this paper are based on more than 450,000 interviews conducted through Gallup’s World Poll in 157 countries in 2012, 2013 and 2014. The sample includes more than 26,000 first-generation migrants and more than 20,000 second-generation migrants. The large sample enables Gallup to analyze first-generation migrants by the duration of their stay in their adopted country and compare their remittance behaviors with second-generation migrants and the native-born.

Marcuse and Habermas's Political Ideas in English

2019 ◽  
pp. 215
Author(s):  
Asaad Abdullwahab AbdulKarim ◽  
Waleed Massaher Hamad ◽  
Salah Ibrahim Hamadi
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Frankfurt School ◽  
Western Thought ◽  
Political Ideas ◽  
Important Impact

Abstract     The Frankfurt School is characterized by its critical nature and it is the result of the Marxist socialist thought as it contributed to the development of the German thought in particular and the Western thought in general through important ideas put forward by a number of pioneers in the various generations of the school and most notably through the leading pioneer in the first generation, Marcuse, and the leading pioneer of the second  generation, Habermas, whose political ideas had an important impact on global thinking and later became the basis of the attic of many critical ideas. In spite of the belief of the school members in the idea of the criticism of power and community, each had his own ideas that distinguish him from the others.

Adsorption Isotherm Predictions for Multiple Molecules in MOFs Using the Same Deep Learning Model

2019 ◽  
Author(s):  
Ryther Anderson ◽  
Achay Biong ◽  
Diego Gómez-Gualdrón
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Molecular Simulation ◽  
Large Scale ◽  
Learning Model ◽  
Operating Conditions ◽  
Small Subset ◽  
Screening Methods ◽  
Large Set ◽  
Metal Organic

<div>Tailoring the structure and chemistry of metal-organic frameworks (MOFs) enables the manipulation of their adsorption properties to suit specific energy and environmental applications. As there are millions of possible MOFs (with tens of thousands already synthesized), molecular simulation, such as grand canonical Monte Carlo (GCMC), has frequently been used to rapidly evaluate the adsorption performance of a large set of MOFs. This allows subsequent experiments to focus only on a small subset of the most promising MOFs. In many instances, however, even molecular simulation becomes prohibitively time consuming, underscoring the need for alternative screening methods, such as machine learning, to precede molecular simulation efforts. In this study, as a proof of concept, we trained a neural network as the first example of a machine learning model capable of predicting full adsorption isotherms of different molecules not included in the training of the model. To achieve this, we trained our neural network only on alchemical species, represented only by their geometry and force field parameters, and used this neural network to predict the loadings of real adsorbates. We focused on predicting room temperature adsorption of small (one- and two-atom) molecules relevant to chemical separations. Namely, argon, krypton, xenon, methane, ethane, and nitrogen. However, we also observed surprisingly promising predictions for more complex molecules, whose properties are outside the range spanned by the alchemical adsorbates. Prediction accuracies suitable for large-scale screening were achieved using simple MOF (e.g. geometric properties and chemical moieties), and adsorbate (e.g. forcefield parameters and geometry) descriptors. Our results illustrate a new philosophy of training that opens the path towards development of machine learning models that can predict the adsorption loading of any new adsorbate at any new operating conditions in any new MOF.</div>

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