cheonan presentation2

8/3/2019 Cheonan presentation2

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Chemistry ofChemistry of absorbatesabsorbates foundfound

from the salvaged ROK navy shipfrom the salvaged ROK navy shipCheonanCheonan and torpedo fragmentsand torpedo fragments

Panseok YangPanseok Yang

Department of Geological SciencesDepartment of Geological SciencesUniversity of ManitobaUniversity of Manitoba


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Overview of underwater explosionOverview of underwater explosion

Summary ofSummary of JIGJIGss investigation of theinvestigation of theadsorbatesadsorbates

YangYangs results and interpretations results and interpretationSeismic evidenceSeismic evidence

A possible cause of the sinking ofA possible cause of the sinking ofCheonanCheonan

Outlines of the talkOutlines of the talk


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Underwater explosion and shock wavesUnderwater explosion and shock waves

water

Detonation wave

Explosive material/

water boundary

Gases

Unreacted material

Torpedo fragments Dense superheated gaseousproducts, 2-4 million PSI (138-

276 kbar) pressure and a fewthousands degree temperature

Chemical explosions withindetonation wave which travelsat a supersonic speed followedby physical explosions byshock waves and bubble pulses

Can the torpedo fragmentswithstand shockwaves andremain within the expandingbubble?


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Bubble pulses and water jetBubble pulses and water jet

Water surface orShip-water boundary


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A torpedo test on Australian navy shipA torpedo test on Australian navy ship

Shock wave Water jet

Gases + Al oxide

Al oxide and diesel oilin the water but notmuch unreactedexplosives

Unknown source

Fractured keel

StationedAmmunitions and fuelswere most likely removed

Aftermath of an UNDEXStrong smell of oilNo smell of explosives


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Settling speed of AlSettling speed of Al22OO

33particlesparticles

40 m

1 m dia. Al2O3

Current: 5.7 km/hr

Torpedo propeller

2)(92 gRv fps

s: settling speed

p

: density of Al2

O3

f: density of seawater: dynamic viscosity of seawaterg: gravitational accelerationR: particle radius

Sea floor

Water surface

Assuming no current, it takes 7.2 hrto reach the sea floor located 40 m below.Under the current speed of 5.7 km/hr,aluminum oxide particles with 1 mdiameter would have drifted 41 km awayfrom the origin.


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Diesel fuelDiesel fuel--clay mineral/Alclay mineral/Al22OO33 interactionsinteractions

Forms oil-seawater-clay mineral/Al2O3flocculated emulsionSubject tobiodegradationPositively buoyant


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Bubble oscillationsBubble oscillations

Water jet of Cheonan ~1.1 sec

Webster, 2007

300 lb TNT (136 kg)


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High explosivesHigh explosives: C: C--HH--OO--NN--Al systemAl system

Solid residues: Al2O3, nano-diamond and/or graphite, and

unreacted explosive materials including Al powder

2N(g) + 2Al(s) = 2AlN(s)

JIG

JIG: amorphous Al2O3 by rapid quenching by seawaterSulfur is not in the system


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SongSongs heat transfer models heat transfer model

Did not take account of Al explosions

Aluminum is added to prolong and to increase bubble size


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Solid explosion productsSolid explosion products

S. D. Gilev and V. F. Anisichkin, 2006Combustion, Explosion, and Shock Waves,Vol. 42, No. 1, pp. 107115

Round, a few tens micronsaluminum oxide balls and

sub micron or lessdiamond

Unreacted Al cores(appear as voids afteracid treatment) coatedwith aluminum oxide

Close-up of aluminum oxide coatings


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Aluminum oxide: AlAluminum oxide: Al

22OO

33

Corundum

Ruby

Sapphire

Alumina

AluminaAl2O3

BoehemiteAlO(OH)

Aluminum hydroxide

Al(OH)3

T

(Dehydration)

crystalline crystalline

crystalline amorphous

Used as gemstone, abrasive, andcatalyst because of physical-chemical resistance


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Carbon polymorphsCarbon polymorphs

Cheonan carbon: hydro carbon (CH, CH2, CH3 etc) as in petroleum products


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The occurrence ofThe occurrence of adsorbatesadsorbates

Under the deck

Abundant in stagnant areas and

commonly associated with Alalloys

JIG

unknown unknown

Absorbates under themetal cover?


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ContinuedContinued

JIG

Underwater explosion experiment

Holding the key but was

not available (limitedquantity)

Not analyzed


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Explosive residuesExplosive residues

Found even in sand but not from the torpedo fragments

JIG

graphite


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JIGJIGss EDS resultsEDS results

JIG interpreted it as a mixture of four different compounds (aluminum oxide, elemental carbon and sulfur, and water)

= =


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JIGJIGss TGA/DTATGA/DTA results and conclusionsresults and conclusions

Continuous decreases in oxygen

Sulfur remains constant up to 600 CThermal decomposition of aluminum sulfate (Al2(SO4)3)occurs at 760 C

Going through phase changes

JIGs conclusion:

Ship = Torpedo fragmentsDid not discuss the meaning of variations


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EDS simulationsEDS simulations

Aluminum hydroxideAl(OH)3

BoehmiteAlO(OH)

Aluminum oxideAl2O3

BasaluminiteAl4(SO4)OH10 5H2O

OAl

S

O

Al

O

Al O Al

AlxOy = Al2O3

X-ray energy (keV)

X-rayintensities(cps)

JIG


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EDS spectrum ofEDS spectrum of wetwet AlAl22OO

33

JIG

O

Al

50 nm alumina


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Nature News,Nature News, volvol 466 July 2010466 July 2010


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SamplingSampling

J. Roh


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Corroded and then adsorbed?Corroded and then adsorbed?Corroded fishing boat propellerCheonan torpedo propeller

White materials below the paint

adsorbates

absorbates

corrosion?

corrosion?Unknown source

Corrosion products underseawater: aluminum hydroxide[Al(OH)3]

This warrants chemical

analyses on the white materialsbelow the paint


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Precipitation vs. adsorptionPrecipitation vs. adsorption

JIG

Stagnant water

clean

clean

Smokestack

unknown

water jet


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SEM, BSE, and TEMSEM, BSE, and TEM

K. Jeong

K. JeongJIG

These textures point to precipitation


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XX--ray mappingray mapping

Detrital Al-silicate

Gypsum


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Quantitative analyses usingQuantitative analyses using

an electron microprobean electron microprobe

Matches with the molecular

formula of basaluminiteAl4(SO4)(Cl0.5OH9.5) 5H2O


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MMicroicro--RamanRaman and FTand FT--IRIR


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Carbon isotopesCarbon isotopesCarbons from diesel fuels of Cheonan


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Natural occurrence ofNatural occurrence of basaluminitebasaluminite

Rio Tinto Mine, Brazil

Sulfide oxidation of pyrite (FeS2)Sulfates and sulfuric acidDissolution of Al from adjacent rocksPrecipitation of basaluminite

Natural basaluminite

Inside the smokestack Propeller


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Precipitation conditions of amorphousPrecipitation conditions of amorphous basaluminitebasaluminite

Amonette et al, 2003

basaluminite

alunogen

Aluminumhydroxide

gibbsite

pH ranges of seawater

Basaluminitecannot be formed

under seawater,requiring moreacidicenvironments


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Ingredients ofIngredients of basaluminitebasaluminite formationformation

JIG p. 61

JIG p. 106

Diesel fuel (bacteria food)Water (seeding bacteria)

Acids (byproducts of dieselbiodegradation)Clay suspensions (Al sources)


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Biodegradation of diesel fuelBiodegradation of diesel fuel

Massive micro-biological populationsCorrosion products (e.g. H2S) by sulfate reducing bacteriaDeterioration of fuel quality

Organic acid accumulationSludge formation


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Dissolution of clay mineralsDissolution of clay minerals


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Evidence of corrosion by dieselEvidence of corrosion by diesel

biodegradation?biodegradation?

unknown

JIG JIG

Water within the vesselenriched in dissolvedmetals

Enhance corrosion in the dotted areas?


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Conclusions and suggestionsConclusions and suggestions

Evidences of underwater explosion such as AlEvidences of underwater explosion such as Al22OO33 andandnanonano--diamond/graphite were not found from the torpedodiamond/graphite were not found from the torpedo

fragments and the ship.fragments and the ship.The white substance is amorphousThe white substance is amorphous basaluminitebasaluminiteprecipitated under more acidic environments thanprecipitated under more acidic environments thanseawater.seawater.

Localized acidic environments can be formed by theLocalized acidic environments can be formed by thebiodegradation of the diesel fuels within the fuel tanks.biodegradation of the diesel fuels within the fuel tanks.

The white substance should not be presented as anThe white substance should not be presented as anevidence of underwater torpedo explosion.evidence of underwater torpedo explosion.

Redo underwater explosion experimentsRedo underwater explosion experiments

Oxygen isotope studyOxygen isotope study


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Seismology and explosionSeismology and explosion

Rogers and Kopper


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KIGAM seismic and sound wave dataKIGAM seismic and sound wave data

Lee, H.

Seismic waves, magnitude = 1.5

Sound wavesTwo peaks with a 1.1 sec intervalFirst peak = shock waveSecond peak = water jet

The interval was used to estimateexplosive power


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CheonanCheonan signalssignals

Hong, 2011


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Kursk signalsKursk signals

Russian Nuclear submarinesank in August, 2000

Rogers and Kopper


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Bubble pulse frequencyBubble pulse frequency

Spacing: function of yield and depth of detonationKursk: 1.45 Hz = 5,000 Kg TNT at 90 meterJIG: 0.91 Hz (1.1 sec) from sound wave = 250-300

Kg TNT at 10 meter

Hong (2011): fundamental frequency of 8.5 Hz andmultiples representing reverberation of watercolumn at 44 meter. No second period of

bubble oscillation.

Detonation depth and yield are questionable.

Kursk

Cheonan

9.1 8.3 8.6

8.5 17.726

34.6

Rogers and Kopper

1.45

KurskHong, 2011 Cheonanham


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My speculation on the sinking ofMy speculation on the sinking of CheonanCheonan

Human torpedo

Illustration from Joongang-Ilbo

= Russian investigators conclusions

Damages similar to a torpedo explosionConsistent with no sonar activities detected beforeand after the explosion

Collision with objects


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AcknowledgementsAcknowledgements

CongresswomenCongresswomen JeongJeong--HeeHee Lee, providingLee, providing CheonanCheonansamplessamples

ReporterReporter JongJong--MyunMyun RohRoh, arranging the investigation, arranging the investigationand presenting the preliminary results at the Nationaland presenting the preliminary results at the NationalAssembly of KoreaAssembly of Korea

Dr.Dr. RavinderRavinder Sidhu, Electron microprobe, EDS and SEMSidhu, Electron microprobe, EDS and SEM

Dr.Dr. YassirYassir Abdu, FTAbdu, FT--IR and Raman SpectroscopyIR and Raman SpectroscopyDr. S.Dr. S. ChaerunChaerun, biodegradation and clay minerals, biodegradation and clay minerals

Neil Ball, XRD analysesNeil Ball, XRD analyses

Misuk Yun, carbon isotope analysesMisuk Yun, carbon isotope analysesDrs.Drs. SeunghunSeunghun Lee and JaeLee and Jae--JungJung SuhSuh, constructive, constructivediscussionsdiscussions

Members of BRIC, critical and valuable discussions overMembers of BRIC, critical and valuable discussions over

many sleepless nightsmany sleepless nights

cheonan presentation2

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