Extension of AUSM-type fluxes: from single-phase gas dynamics to multi-phase cryogenic flows at all speeds

Shock Waves ◽  
2019 ◽  
Vol 29 (5) ◽  
pp. 735-753
Author(s):  
H. Kim ◽  
C. Kim
Keyword(s):  
Gas Dynamics ◽  
Single Phase ◽  
All Speeds ◽  
Multi Phase ◽  
Cryogenic Flows

The Work Hardening of Single Phase and Multi-Phase Aluminium Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 71-78 ◽  
Author(s):  
J. David Embury ◽  
Warren J. Poole ◽  
David J. Lloyd
Keyword(s):  
Work Hardening ◽  
Aluminium Alloys ◽  
Single Phase ◽  
Dynamic Recovery ◽  
Uniform Elongation ◽  
Strengthening Mechanisms ◽  
Plastic Response ◽  
Spring Back ◽  
Hardening Process ◽  
Multi Phase

The process of work hardening in aluminum alloys is important from the viewpoint of formability and the prediction of the properties of highly deformed products. However the complexity of the strengthening mechanisms in these materials means that one must carefully consider the interaction of dislocations with the detailed elements of the microstructure and the related influence of the elements on dislocation accumulation and dynamic recovery. In addition, it is necessary to consider the influence of the work hardening process at various levels of plastic strain. This permits the possibility of designing microstructure for tailored plastic response, e.g. not simply designed for yield strength but also considering uniform elongation, spring-back, ductility etc. This presentation will explore the concept of identifying the various interactions which govern the evolution of the work hardening and their possible role in alloy design.

Abstract 77: Ongoing Leakage Revealed by Second Phase Spot Sign Volume Expansion in Multi-Phase Computed Tomography Angiography Strongly Predicts Intracranial Hemorrhage Growth

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Abdulaziz Al Sultan ◽  
Ericka Teleg ◽  
MacKenzie Horn ◽  
Piyush Ojha ◽  
Linda Kasickova ◽  
...  
Keyword(s):  
Volume Expansion ◽  
Single Phase ◽  
Meta Analysis ◽  
Hematoma Expansion ◽  
Second Phase ◽  
Hematoma Volume ◽  
Spot Sign ◽  
Time Resolved ◽  
Multi Phase

Background: CTA spot sign is a predictor of intracerebral hemorrhage (ICH) expansion. This sign can fluctuate in appearance, volume, and timing. Multiphase CTA (mCTA) can identify spot sign through 3 time-resolved images. We sought to identify a novel predictor of follow up total hematoma expansion using mCTA. Methods: This cohort study included patients with ICH between 2012-2019. Quantomo software was used to measure total hematoma volume (ml) from baseline CT & follow-up CT/MRI blinded to spot sign in 3 mCTA phases. Spot sign expansion was calculated by subtracting 1 st phase spot sign volume from 2 nd phase spot sign volume measured in microliters. Results: 199 patients [63% male, mean age 69 years, median NIHSS 11, IQR 6-20] were included. Median baseline ICH volume was 16.1 ml (IQR 5-29.9 ml). Amongst all three mCTA phases, spot sign was best detected on the 2nd phase (23% vs 17.5% 1 st phase vs 22% 3 rd phase). In multivariable regression, spot sign expansion was significantly associated with follow up total hematoma expansion (OR: 1.03 per microliter of spot sign expansion, p=0.01). Figure 1 shows the predicted total hematoma expansion by spot sign expansion. mCTA spot sign had a higher sensitivity for predicting total hematoma volume expansion than single-phase CTA (reported in meta-analysis of 14 studies), 86% vs 53%, respectively, while both having similar specificity, 87% vs 88%, respectively. Conclusion: Spot sign expansion on mCTA is a novel predictor of total hematoma expansion and could be used to select patients for immediate therapeutic intervention in future clinical trials. Using mCTA improves sensitivity while preserving specificity over single-phase CTA.

scholarly journals Outcome Prediction Using Perfusion Parameters and Collateral Scores of Multi-Phase and Single-Phase CT Angiography in Acute Stroke: Need for One, Two, Three, or Thirty Scans?

2018 ◽  
Vol 20 (3) ◽  
pp. 362-372 ◽  
Author(s):  
Katharina Schregel ◽  
Ioannis Tsogkas ◽  
Carolin Peter ◽  
Antonia Zapf ◽  
Daniel Behme ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Ct Angiography ◽  
Single Phase ◽  
Outcome Prediction ◽  
Multi Phase

Eco-driving control of electric vehicle with battery dynamic model and multiple traffic signals

2021 ◽  
pp. 095440702110374
Author(s):  
Hafiz Muhammad Yasir Naeem ◽  
Aamer Iqbal Bhatti ◽  
Yasir Awais Butt ◽  
Qadeer Ahmed
Keyword(s):  
Life Cycle ◽  
Boundary Value Problem ◽  
Single Phase ◽  
Boundary Value ◽  
Optimization Technique ◽  
Traffic Signals ◽  
Multiple Shooting ◽  
Point Boundary ◽  
Phase Problem ◽  
Multi Phase

Limited capacity and short life cycle of a battery are the major impediments in development of practical Electric Vehicles (EVs). Eco-driving is an optimization technique through which a velocity trajectory that consumes minimum energy is advised to the driver. However, presence of traffic signals to control large traffic network degrades the performance of eco-driving; as applying brakes to stop and then maximum re-acceleration to restart a trip consumes lot of energy. Eco-driving problem with multiple traffic signals and static model of battery has been proposed as Two Point Boundary Value Problem (TPBVP). TPBVP fails to solve multi-phase problem as a single phase due to discontinuity of the co-states at the junction, that is, start of a new phase. This paper investigates an optimal solution with both EV and battery dynamics in the presence of multiple traffic signals as Multi Point Boundary Value Problem (MPBVP) using multiple shooting technique. Traffic signals come at some intermediate points of a trip. MPBVP ensures continuity at the junction to solve the multi-phase problem as a single phase through inter dependencies between each phases. Goal of this work is not only to solve constrained eco-driving problem with traffic signals but also include charging and discharging limits on battery that indirectly improves battery’s life cycle. Results indicate that EV has crossed all the traffic signals during their green duration without applying brakes with also satisfying all the other constraints and continuity condition. Moreover, it can be seen that energy consumption using MPBVP is also marginally lesser as compared to TPBVP.

Analytical Electrical Conductivity Models for Single-Phase and Multi-Phase Fractal Porous Media

Fractals ◽  
2021 ◽  
Author(s):  
Wenhui Song ◽  
Masa Prodanovic ◽  
Jun Yao ◽  
Kai Zhang ◽  
Qiqi Wang
Keyword(s):  
Electrical Conductivity ◽  
Porous Media ◽  
Single Phase ◽  
Multi Phase ◽  
Conductivity Models

High-Temperature Mechanical Behavior of B2 Type IrAl Doped With Ni

1996 ◽  
Vol 460 ◽  
Author(s):  
A. Chiba ◽  
T. Ono ◽  
X. G. Li ◽  
S. Takahashi
Keyword(s):  
Steady State ◽  
Mechanical Behavior ◽  
Constant Velocity ◽  
Single Phase ◽  
Elevated Temperatures ◽  
Constant Load ◽  
Secondary Creep ◽  
Compression Tests ◽  
Order Of Magnitude ◽  
Multi Phase

ABSTRACTConstant-velocity and constant-load compression tests have been conducted to examine the mechanical behavior of polycrystalline IrAl and Ir1-xNixAl at ambient and elevated temperatures. Although IrAl exhibits brittle fracture before or immediately after yielding below 1073K, steady-state deformation takes place at temperatures higher than 1273K. Ductility of Ir1-xNixAl is improved with increasing x. On the contrary, strength decreases with increasing x. IrAl exhibits the 0.2% flow stress of 1200MPa at 1073K and 350MPa at 1473K, about an order of magnitude higher than NiAl. Secondary creep of IrAl and Ir0.2Ni0.8Al(i.e., modified NiAl) exhibits class II and class I behavior respectively. Creep strength of binary IrAl and modified NiAl with Ir is about a magnitude of 4 higher than that of single-phase and multi-phase NiAl at a given applied stress.

Cavitation in Hydraulic Machines: Measurement, Numerical Simulation and Damage Patterns

2020 ◽  
Author(s):  
Helmut Benigni
Keyword(s):  
Single Phase ◽  
Rapid Assessment ◽  
Vapor Bubbles ◽  
Test Rig ◽  
Liquid Media ◽  
Histogram Method ◽  
Pressure Drops ◽  
Physical Limit ◽  
Hydraulic Machines ◽  
Multi Phase

Abstract Cavitation is a phenomenon that occurs in liquid media when the pressure drops below the vapor pressure. Cavitation is accompanied by damage when the imploding vapor bubbles implode in the vicinity of components. Cavitation is known in all hydraulic machines, be it a pump or a turbine, and it can occur within all components that are flowed through and have a low-pressure side or area. In the last 100 years, a lot has been done to understand the damage caused by cavitation, and cavitation has been classified within the entire range of component-damaging mechanisms. Nevertheless, users are now interested in the behavior of different machine types and different specific speeds and need information for a particular installation situation, while hydraulic developers are interested in a methodology for the rapid assessment of CFD results. This paper presents examples of damage to all kinds of hydraulic machines as well as numerical simulations of cavitation. Cross-comparisons between single-phase numerical calculations are realized with the histogram method, and multi-phase calculations are carried out and then compared with test rig investigations. Often, it is not possible or economically feasible to completely avoid cavitation. With the help of dimensionless values and the assumption of complete cavitation, a generally valid physical limit curve can be specified for turbines.

Identification and Prioritization of Generic Nuclear Safety Problems Requiring CFD Analysis

2009 ◽  
Author(s):  
Brian L. Smith
Keyword(s):  
Single Phase ◽  
Safety Issues ◽  
Group A ◽  
Computational Fluid Dynamics Cfd ◽  
Specific Safety ◽  
Multi Phase ◽  
High Cycle Thermal Fatigue ◽  
Specific Concern ◽  
Country Specific

Within the framework of the activities and responsibilities of the OECD/NEA/WGAMA group, a modest PIRT-type exercise was initiated to identify and prioritize country-specific safety issues for which it was considered that analysis using Computational Fluid Dynamics (CFD) could bring real benefits in regard to improved safety. Conventional PIRT procedures were followed as far as possible: the problem scope and objectives of the exercise were first defined, and then a panel of experts was assembled to identify and prioritize the safety items of specific concern to the country represented. Collating the information received, it was possible to identify those safety issues which were clearly country-specific in origin, and those which were of generic interest for which a common approach to benchmarking would be justified. Separate lists were compiled for single-phase and multi-phase phenomena. The paper summarizes the procedures undertaken, lists and prioritizes the safety topics identified in the study, and presents the final ranking in terms of generic importance. Also described are perspectives for a first follow-up activity: the promotion of a new validation benchmark activity based on the problem of high-cycle thermal fatigue in mixing tees.

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