conference 2007

8/2/2019 Conference 2007

1/27

ARC

Simulink Based Vehicle Cooling

System Simulation;

Series Hybrid Vehicle CoolingSystem Simulation

13th ARC Annual ConferenceMay 16, 2007

SungJin Park, Dohoy Jung, and Dennis N. Assanis

University of Michigan


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Outline

Introduction Motivation

Objectives

Simulation and Integration

Hybrid vehicle system modeling [VESIM]

Cooling system modeling

Configuration of HEV cooling system

Summary


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Vehicle thermal management andcooling system design

Motivation Additional heat sources

(generator, motor, power bus,battery)

Various requirements for differentcomponents

Objective Develop the HEV Cooling System

Simulation for the studies on thedesign and configuration ofcooling system

Optimize the design and theconfiguration of the HEV coolingsystem Conventional Cooling System

Radiator1

OilCooler

FAN

Thermostat

Pump

By-Pass

CAC2

Grille

A/C Condenser

HEV Cooling System


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Overview of Cooling System Simulation

Cooling system model use simulation data from thehybrid system model

Minimizes computational cost for optimization of designand configuration

Hybrid Propulsion System Model [VESIM] HEV Cooling System Model

0

10

20

30

40

50

60

0 200 400 600 800 1000 1200

1400

Velocity(MPH)

Time (s)

Driving schedule

-200

-100

0

100

200

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500

time(sec)

0

100

200

300

400

-100

0

100

200

300

400

500

600

700

0 100 200 300 400 500

time(sec)

-1500

-1000

-500

0

500

1000

1500

-200

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500

time(sec)

-1000

-500

0

500

1000

1500

2000

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500

time(sec)


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Hybrid propulsion systemconfiguration and VESIM

Engine

Generator

Vehicle

Motor

BatteryController

PowerBus

EngineGenerator

Power Bus

Battery

Motor

Wheel

Engine 400 HP(298 kW)

Motor2 x 200 HP(149 kW)

Generator

400 HP

(298 kW)

Battery

(lead-acid)

18Ah /

25 modules

Vehicle

20,000 kg

(44,090 lbs)

Maximumspeed

45 mph

(72 kmph)


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Hybrid vehicle power management

Discharging mode Charging mode Braking mode

Wheel

Motor

Generator

Motor

Power BusControllerEngine

Battery

Wheel

Wheel

Motor

Generator

Motor

Power BusController

Engine

Battery

Wheel

Battery is the primary powersource

When power demand exceedsbattery capacity, the engine isactivated to supplement powerdemand

Power Flow

Active ConditionallyActive

Inactive

Engine / generator is the primarypower source

When battery SOC is lower thanlimit, engine supplies additionalpower to charge the battery

Once the power demand is

determined, engine is operated atmost efficient point

Wheel

Motor

Generator

Motor

Power BusControllerEngine

Battery

Wheel

Regenerative braking is activatedto absorb braking power

When the braking power is largerthan motor or battery limits,friction braking is used

SOC High Limit

SOC Low Limit

Charge Discharge Charge

SOC

Engine Speed

EngineTorque

Efficiency ( engine + generator )


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0.55

0.6

0.65

0.7

0.75

0 100 200 300 400 500

time(sec)-1500

-1000

-500

0

500

1000

1500

-200

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500

time(sec)

-200

-100

0

100

200

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500

time(sec)

-1000

-500

0

500

1000

1500

2000

0

500

1000

1500

2000

2500

3000

0 100 200 300 400 500

time(sec)

Vehicle simulationVehicle driving cycle

Cycle simulation results ( engine / generator / motor / battery)

Vehicle simulation model [VESIM]

Engine Speed Generator Speed Motor Speed

Engine BMEP Generator Torque Motor Torque

0

10

20

30

40

50

60

0 100 200 300 400 500

vehicle speed (demand)vehicle speed (actual)

time(sec)

Battery SOC


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Cooling system modeling;Configurations

Configuration A

Motor(A/B)

Generator

PowerBusRadiator1

Engine

Radiator2

FAN

Thermostat

Pump

ElectricPump

By-

Pass

CAC1

Grille

Radiator1

OilCooler

FAN

Thermostat

Pump

By-Pass

CAC2

Grille

A/C Condenser

HEV Cooling System Model in Matlab Simulink

Cooling Circuit for Electric Parts

Cooling Circuit for Engine

Cooling Circuit Tower 2

cac spec

in le ra irve locity

inlet airtemperature

turbo charger

Ramass

thermodelP

coolant temp, K

inlet airvelocity, m/s

inlet airtemp, oC

Ramass1

Tcoolout

thermodelP1

RadelP, bar

to fan

outlet airtemp, K

radiator2

Ramass

thermodelP

coolant temp, K


inlet airtemp, oC

Ramass1

Tcoolout

thermodelP1

RadelP, bar

to fan

outlet airtemp, K

radiator1

coolant m(kg/s)

coolant density,kg/m3

f low coef f cac

f low coef f egn

coolant flow1

coolant flow2

coolant flow3

m_sum

dp(bar)

parallel coolant circuit2

coolant m(kg/s)

coolant density,kg/m3

coolant flow1

coolant flow2

coolant flow3

m_sum

dp

parallel coolant circuit1

coolant flowrate (kg/s)

coolant temp in (K)

coolant temp

mc temp

motor(A,B)/

controller


coolant temp in (K)

coolant temp

gc temp

generator/

control l er

0.2102

0.05466

0.1089

0.3737

0.003829

336.5

flowrate 1

flowrate 2

flowrate 3

fl owsum

dp

temp1

heat rejection, kW

cool mass1

coolant temp

Tcool_out

f low coef f a /b /c

engine block

heat rejection rate

pump speed

engine

pump speed

pressure rise, bar

coolant temp

coolant mass

pressure rise

cool mass, kg/s

coolant temp, K

coolant density, kg/m1

coolant pump2

pump speed

pressure rise, bar

coolant temp

coolant mass

pressure rise

cool mass, kg/s

coolant temp, K


coolant pump1

T_pb

T_gen

T_mot

motor_rpm

fan on/off

coolant pump motor /control l er

coolant temp1

coolant mass

delP

recirculate massradiatormass

coolant temp2Re delP

thermo delPdelP1

Remass

Recooltemp

RedelP

Ramass

Racooltemp

RadelP

enginedelP

thermodelP

coolant mass

coolant temp

pressure drop2

collector4

Remass

Recooltemp

RedelP

Ramass

Racooltemp

RadelP

enginedelP

thermodelP

coolant mass

coolant temp

pressure drop2

collector3

T1

T2

m1

m2

Tsum

collector1

T1

T2

T3

m1

m2

m3

Tsum

collector0

fan speed, rpm

vehicle speed, km/h

inlet airtemp, oC

radiator2 spec

radiator1 spec

radi out airT

inlet airvel 1, m/s

inlet airvel 2, m/s

inlet airtemp, oC

ai rs ide, fan

Teng

Telec

fan_rpm

V_speed

Ta

ai rs ide input

rad_air_temp

To Fi l e6

delp.mat

To Fi l e5

mass.mat

To Fi l e4

temp.mat

To Fi l e3

delp_e.mat

To File2

mass_e.mat

To Fi l e1

temp_e.mat

To Fi l e

Terminator2

Terminator

coolant temp1

coolant mass

delP

recirculate mass

radiatormass

coolant temp2

Re delP

thermo delP

T/S temp

delP1

T/S2

Load input data

C_m (kg/s)

C_Tin(K)

C_m(kg/s)

C_Tout(K)

Reservoir2

C_m (kg/s)

C_Tin(K)

C_m(kg/s)

C_Tout(K)

Reservoir1


coolant temp in (K)

coolant temp

pb temp

PowerBus

u(1)-273

K->oC

1800

Display3

371 .1

Display1

Clock

f(u)

C2K

cool_mass

coolant temp, K


inlet airtemp, oC


Tcoolout

f low coef f a /b /c

outlet airtemp, K

cac spec

1st charge ai rcooler

MotorGenerator PowerBus

Radiator1

Radiator2

T/S

ElectricPump

Engine

CAC1

ParallelCircuit

ParallelCircuit

Mech.Pump

EngineBlock

Fan

TurboCharger

Cooling Circuit Tower 1

*Run Tower2 firstcopy "to_cac2_t_T.mat"

cac spec

inlerairv elocity

inlet airtemperature

turbo charger

Ramass

thermodelP

coolant temp, K


inlet airtemp, oC


Ramass1

Tcoolout

thermodelP1

RadelP, bar

to fan

outlet airtemp, K

radiator

f(u)

oC->K

pump speed

heat rejection rate

engine

pump speed,

pressure rise, bar

coolant temp

coolant mass

pressure rise (bar)

cool mass, kg/s

coolant temp, K


coolant pump

Remass

Recooltemp

RedelP

Ramass

Racooltemp

RadelP

enginedelP

thermodelP

coolant mass

coolant temp

pressure drop2

collector1

fan speed, rpm

vehicle speed, km/h

inlet airtemp, oC

radiator2 spec

radiator1 spec

radi out airT

inlet airvel 1, m/s

inlet airvel 2, m/s

inlet airtemp, oC

airside, fan

Tcool out

fan_rpm

V_speed

Ta

airside input

rad_air_temp

To File

coolant temp1

coolant mass

delP1

delP2

recirculate mass

radiatormass

coolant temp2

Re delP

thermo delP

T/Stemp

delP_sum

T/S

Load input data

C_m (kg/s)

C_Tin(K)

C_m(kg/s)

C_Tout(K)

Reservoir1


coolant temp in (K)

heat rejection rate(kW)

coolant temp

cool mass

Oil coolerdp(bar)

Oil cooler1

f(u)

K->oC

0

Display4

0

Display3

0

Display20

Display11

0

Display1

Clock


inlet airtemp, oC

to fan

outlet airtemp, K

A/C

cool_mass

coolant temp, K


inlet airtemp, oC

coolant density kg/m3

cool_mass1

Tcoolout1

outlet airtemp, oC

cac spec

delP(bar)

2nd charge aircooler

Radiator

A/CCondenserT/S

CAC2

Mech.Pump

Fan

OilCooler


9/27

ARC

Guide Lines ofCooling system configuration

Criteria for system configuration Radiators for different heat

source components areallocated in two towers basedon operation group

The radiators are arranged inthe order of maximumoperating temperature

Electric pumps are used forelectric heat sources

The A/C condenser is placed inthe cooling tower where theheat load is relatively small

Battery is assumed to be cooledby the compartment A/Csystem due to its low operatingtemperature (Lead-acid: 45oC)

ComponentHeat

generation(kW) *

ControlTargetT (oC)

Operationgroup**

Engine 190 120 A

Motor /controller

27 95 B

Generator /

controller

65 95 A

Charge aircooler

13 - A

Oil cooler 40 125 A

Power bus(DC/DC

converter)

5.9 70 C

Battery*** 12 45 D

* Grade Load condition

** The heat sources that generate heat simultaneously duringdriving cycle are grouped together.

*** Maximum speed condition / Lead-acid


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ConfigurationsConfiguration B

Motor(A/B)

PowerBus

Radiator1

Radiator2

FAN

ElectricPump

Grille

ElectricPump

A/C Condenser

Generator

Radiator3

FAN

ElectricPump

Grille

Radiator2

CAC

Radiator1

OilCooler Thermostat

Pump

By-Pass

Engine

Pump

Generator

Radiator3

FAN

ElectricPump3

Grille

Radiator2

CAC

Radiator1OilCooler

Thermostat

Pump1

By-Pass

Engine

Pump2

Motor(A/B)

PowerBus

Radiator1

Radiator2

FAN

ElectricPump

Grille

ElectricPump

A/C Condenser

Configuration C

Po

werGeneration

VehiclePro

pulsion


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Modeling Approach

Component Approach Implementation

Heat Exchanger Thermal resistance concept 2-D FDM Fortran (S-Function)

Pump Performance data-based model Matlab/Simulink

Cooling fan Performance data-based model Fortran (S-Function)

Thermostat Modeled by a pair of valves Fortran (S-Function)

Engine Map-based performance model Matlab/Simulink

Engine block Lumped thermal mass model Matlab/Simulink

Generator Lumped thermal mass model Matlab/Simulink

Power bus Lumped thermal mass model Matlab/Simulink

Motor Lumped thermal mass model Matlab/Simulink

Oil cooler Heat exchanger model (NTU method) Matlab/Simulink

Turbocharger Map-based performance model Matlab/Simulink

Condenser Heat addition model Matlab/Simulink

Charge air cooler Thermal resistance concept 2-D FDM Fortran (S-Function)


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Heat Input and Exchange Model for

Engine Block and ElectricComponents Lumped thermal mass model

Heat transfer to cooling path (Qint) and toouter surface (Qext; radiation and naturalconvection)

Engine Map based engine performance model

Heat rejection rate as a function of speedand load is provided by map

Turbo Charger Map base turbo charger performance

model

The temperature and flow rate of thecharge air as functions of speed and loadare provided by map

Schematic of Heat Exchange Modelat Engine and Electric components

Coolant Flow

Q

Qint

Qext

Modeling Approach:Heat source

Engine heat rejection rate


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Modeling Approach:Heat sources (cont.)

Oil Cooling Circuit

Heat addition model : heat is directly added to the oil Heat rejection rate as a function of speed and load is provided by map

Condenser Heat addition model: heat is directly added to the cooling air

Constant value is used for heat rejection rate

Heat generation from generator is handled as 2-Dlookup table indexed by rotor speed and input torque

Map based Generator and Controller model

1_ TQ genm

Charge air coolers 2-D FDM-based model

In contrast to radiator, heattransfer occurs from air tocoolant

Generator Heat generation is calculated

using a 2D look-up table indexedby speed and input torque

Lumped thermal mass model


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Power Bus Model

mc

mcmc

copbgenpb

wTVIVIabsQ

)1(1_

Battery charging& Motor is working

Otherwise :Motor is working

Motor is generating

mc

mcmc

pbgenpb

wTQ

1_

mcmcmcpbgenpb wTQ 1_

Modeling Approach:Heat sources (cont.)

Motors Heat generation is calculated

using a 2D look-up tableindexed by speed and inputtorque

Lumped thermal mass model

Power bus Power bus regulates the power

from electric power sources andsupply the power to electricpower sink

Heat generation is determined

by battery and motor power Lumped thermal mass model

Heat generation from motor is handled as 2-D lookuptable indexed by rotor speed and output torque

Map based Motor and Controller model

1

1_

TQ genm

Motor

Battery

Power Bus

Motor

Battery

Power Bus

Motor

Battery

Power Bus


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Modeling Approach:Heat sinks

Heat exchanger (radiator)

Design variables Core size

Water tube : depth, height, thickness

Fin : depth, length, pitch, thickness

Louver : length, height, angle, pitch

Based on thermal resistance concept

2-D Finite Difference Method

05.028.068.023.029.014.027.0

49.0

90Re

l

f

l

t

l

l

l

t

l

f

l

f

PP

t

P

P

P

L

P

D

P

L

P

Pj

l

i=12 .

..

Ni

j=1

2

.

.

.

.

.

.

.

Nj

Staggered grid system for FDM

Design parameters of CHE core

Structure of a typical CHE

3/2

,

Prapaa

a

CV

hj

Empirical correlation for ha

(by Chang and Wang)


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Modeling Approach:Heat sinks(cont.)

Oil cooler

Finned concentric pipe heat exchanger modelfor Oil Cooler

Counter flow setup

NTU approach is used to calculate the exittemperature of two fluids

NTU MethodSchematic of Heat Exchange atEngine and Electric components


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Modeling Approach:Delivery media (Coolant)

Coolant Pumps

The coolant flow rate is calculatedwith calculated total pressure drop bycooling system components and thepump operating speed

Performance map is used to calculatethe coolant flow rate

The mechanical pump is driven byengine and electric pump is driven byelectric motor

by- pass

coolant pump

engine

passbyheatpump PPP

radiatorheat PP

by- passby- pass

coolant pump

Heat 1

thermostat

radiator

Coolant circuit(driven by engine)

passbypump PPP

radiatorPP

Heat 2

coolant pump

engine

pumpP radiatorheat PP

coolant pump

Heat 1

radiator

Coolant circuit(driven by motor)

pumpP radiatorPP

Heat 2

Performance Maps of Mechanical Pump

EfficiencyFlow rate

Performance Maps of Electric Pump

EfficiencyFlow rate


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Open

Close

Modeling Approach:Delivery media (Coolant)

radiatorvalveSTrapiperacircuit PPPP _/__

valveSTrepiperecircuit PPP _/__

22

22

reloss

re

re

rere

VK

V

D

Lf

QPV

K

V

D

L

f radiatorra

loss

ra

ra

ra

ra 22

22

P Pipe (radiator circuit)P radiatorP radiatorP

P Pipe (re-circulate circuit)PP T/S_ to_re-circulateP

P T/S_ to_radiatorP

To Pump

From

HeatSources

Valve lift curve of T/S

recircuitracircuit PP __ recircuitracircuit PP __

Coolant flow calculationbased on pressure drop

radiatorcerecirculatctotalc QQQ ___ radiatorcerecirculatctotalc QQQ ___

Thermostats

Two way valve with Hysteresis characteristics Coolant flow rate to re-circulate circuit and radiator are determined

by the pressure drops in each circuit

-2

0

2

4

6

8

10

12

14

365 370 375 380

Temperature (K)

Open

Close

T/S valve lift with hysteresis


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Modeling Approach:Delivery media (Oil/Air)

Oil Pump Map based gear pump model for Oil

Pump

Cooling fans Total pressure drop is calculated from

the air duct system model based on

system resistance concept Performance map is used to calculate

the air flow rate Map Based Gear Pump Model

Cooling air flow circuit

upstream

cooling air flow

Cooling air flow circuit

downstream

radiator2 grilleradiator1fan &shroud

Air duct system based on system resistance concept

condenser

Fan & Shroud

Radiator 1,2

Grille

Condenser


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Test conditions

Test condition for sizing components and evaluating coolingsystem configuration

The thermal management system should be capable ofremoving the waste heat generated by the hardware underextreme operating condition

Grade load condition is found to be most severe condition forcooling system

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0 200 400 600 800 1000

distance(m)

Road profile of off-road condition

Ambient Temperature 40 oC

45mi/h 30mi/h

30mi/h

7%

Grade Load Maximum Speed Off-Road

C fi i


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Configuration test;Grade Load (30 MPH, 7 %)

Max. SOC: 0.7Min. SOC: 0.6Initial SOC: 0.6

0 200 400 600 800 1000 1200 1400 1600 18000

200

400

600

800

1000

1200

1400

1600

1800

2000

time [sec]

speed[rpm]

Engine speed

0 200 400 600 800 1000 1200 1400 1600 18000

200

400

600

800

1000

1200

1400

1600

Engine BMEP

time [sec]

BMEP[kPa]

0 200 400 600 800 1000 1200 1400 1600 18000.5

0.55

0.6

0.65

0.7

0.75

0.8

time [sec]

SOC

Battery State of Charge

30mi/h

7%

Grade Load

Engine Speed Engine BMEP

Battery SOC


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Configuration A and B

Motor(A/B)

Generator

PowerBusRadiator1

Engine

Radiator2

FAN

Thermostat

Pump

ElectricPump

By-Pass

CAC1

Grille

Motor(A/B)

PowerBus

Radiator1

Radiator2

FAN

ElectricPump

Grille

ElectricPump

A/C Condenser

Generator

Radiator3

FAN

ElectricPump

Grille

Radiator2

CAC

Radiator1

OilCooler

Thermostat

Pump

By-Pass

Engine

Pump

Radiator1

OilCooler

FAN

Thermostat

Pump

By-Pass

CAC2

Grille

A/C C ondenser

Config. A could not meet the cooling

requirements of electric componentsConfiguration A Configuration B

Generator Generator

Motor

PowerBusPowerBus

Motor


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ARC

Configuration A and B

Motor(A/B)

Generator

PowerBusRadiator1

Engine

Radiator2

FAN

Thermostat

Pump

ElectricPump

By-Pass

CAC1

Grille

Motor(A/B)

PowerBus

Radiator1

Radiator2

F

ElectricPump

Grille

ElectricPump

A/C Condenser

Generator

Radiator3

FAN

ElectricPump

Grille

Radiator2

CAC

Radiator1

OilCooler

Thermostat

Pump

By-Pass

Engine

Pump

Radiator1

OilCooler

FAN

Thermostat

Pump

By-Pass

CAC2

Grille

A/C C ondenser

Performance of one CAC inConfig. B was better than that oftwo CAC in Config. A

Configuration A Configuration B

CAC1

CAC2

CAC


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ARC

Configuration B and C

Motor(A/B)

PowerBus

Radiator1

Radiator2

FAN

ElectricPump

Grille

ElectricPump

A/C C ondenser

Generator

Radiator3

FAN

ElectricPump

Grille

Radiator2

CAC

Radiator1

OilCooler

Thermostat

Pump

By-Pa

ss

Engine

Pump

Config. C is designed by addinga coolant by-pass line to OilCooler in Config. B

Power consumption of pump isreduced by 5% adding thebypass circuit

Generator

Radiator3

FAN

Electric

Pump3

Grille

Radiator2

CAC

Radiator1OilCooler

Thermostat

Pump1

By-Pas

s

Engine

Pump2

Motor(A/B)

PowerBus

Radiator1

Radiator2

FAN

Electric

Pump

Grille

Electric

Pump

A/C Condenser

Configuration B Configuration C

2.5

2.75

3

3.25

3.5

3.75

4

0 300 600 900 1200 1500 1800

no by-passmean (no by-pass)by-passmean (by-pass)

time (sec)


25/27

ARC

Summary

The HEV Cooling System Simulation is developed for the

studies of the cooling system design and configuration

The HEV cooling systems are configured using the simulation

In hybrid vehicle, the heat rejection from electric componentsis considerable compared with the heat from the engine ( GradeLoad : heat from electric components 98kW, heat from engine module 240kW)

Proper configuration of cooling system is important for hybridvehicle components, because the electric components workindependently and have different target operatingtemperatures

Parasitic power consumption by the cooling components can be

reduced by optimal configuration design Optimization study of cooling system is conducted using

developed model (Symposium II, Optimal design of electric-hybrid powertrain cooling system)


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ARC

Acknowledgement

General Dynamics, Land Systems (GDLS)


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ARC

Thank you!

conference 2007

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