Questo lavoro è stato supportato dalla NASA concessione NNX11AC68G e Carnegie Institution di Washington. Ringrazio Chi Zhang per la sua assistenza con la raccolta dei dati. Ringrazio anche Anat Shahar e Valerie Hillgren per voti recensioni di questo manoscritto.

1. Preparare materiali di partenza e delle Camere di esempio <ol><li> Preparare due tipi di materiali di partenza, (1) una miscela di olivina silicato naturale e polvere di ferro metallico con 10% in peso di zolfo (metallo / rapporti silicato vanno da 4 a 30% in peso) per simulare percolazione di lega di ferro liquido in una matrice di silicato solido durante la formazione del nucleo iniziale di un piccolo corpo planetario, e (2) una miscela omogenea di ferro puro finemente a terra e solfuro di ferro per la determinazione del planetario nucleo di cristallizzazione interno. </li><li> Macinare i materiali di partenza per polvere fine mista sotto etanolo in un mortaio di agata per un&#39;ora ed essiccato a 100 ° C. </li><li> Caricare il materiale di partenza in un MgO sinterizzato o Al 2 O 3 capsula (tipicamente 1,5 mm di diametro e 1,5 di lunghezza), e poi riporla in un gruppo della cella di alta pressione per gli esperimenti multi-incudine. </li><li> Caricare il composto Fe-FeS in una piccola camera del campione (tipicamente 100 micron di diametro e 25 &amp; #181; m di spessore) forato in una guarnizione renio preindented per gli esperimenti laser-riscaldamento nella cella diamante-incudine. Panino la miscela di Fe-FeS tra gli strati di NaCl che fungono da isolanti termici. </li></ol> 2. Gli esperimenti ad alta pressione e ad alte temperature nell&#39;apparato Multi-incudine <ol><li> Il gruppo della cella di alta pressione multi-incudine consiste di un ottaedro MgO come mezzo di pressione, un manicotto ZrO 2 come isolante termico, e un renio cilindrica o riscaldatore grafite. La capsula campione si inserisce all&#39;interno del riscaldatore. Una termocoppia di tipo C viene inserito nella camera del campione per determinare la temperatura del campione. </li><li> Posizionare il gruppo ad alta pressione in un apparecchio ad alta pressione multi-incudine per la pressurizzazione. </li><li> L&#39;apparato multi-incudine è costituito da una pressa idraulica 1.500 ton e un modulo di pressione che contiene un anello di ritenuta con sei cunei di spinta rimovibili formando una cavità cubica al centro 15. Il cubo della cavità houses otto cubi in carburo di tungsteno con angoli troncati. I cubi troncati, che convergono sul gruppo cella ottaedro, vengono separati l&#39;uno dall&#39;altro da guarnizioni comprimibili. Il pistone idraulico trasmette la forza efficace sul gruppo campione da una configurazione a due stadi incudine. Figura 1 illustra la procedura sperimentale per l&#39;esperimento multi-incudine. </li><li> Pressurizzare il campione ad una pressione designata tra 2-27 GPa a temperatura ambiente basato su punto fisso curva di calibrazione di pressione 16, e poi riscaldare a temperature sperimentali fino a 2.300 ° C mediante riscaldamento a resistenza elettrica; mantenere l&#39;esperimento a temperatura costante per tutta la durata dell&#39;esperimento, e disattivare l&#39;alimentazione per spegnere il campione a temperatura ambiente al fine dell&#39;esperimento. </li><li> Rilasciare lentamente la pressione aprendo la valvola dell&#39;olio idraulico e recuperare la carica sperimentale. </li></ol> 3. Esperimenti laser di riscaldamento inDiamond-incudine cellulare <ol><li> Pressione in una cella di diamante incudine è generato tra due incudini di diamante gemma-qualità cristallo singolo (circa 0,25 carati ciascuno). Usiamo una cella di diamante-incudine simmetrica per guidare le incudini opposte perfettamente allineate con un sistema cilindro-pistone. La cella è in grado di generare pressioni corrispondenti alle condizioni di pressione del nucleo della Terra 17. Temperatura elevata viene ottenuta mediante riscaldamento laser nella cella diamante-incudine. Utilizziamo un sistema al Advance Photon Source (APS), che si basa su un laser tecnica biadesivo riscaldamento e consiste di due laser a fibra ottica, per riscaldare il campione da entrambi i lati, e due sistemi spettroradiometriche per misure di temperatura su entrambi i lati 18. Il sistema è progettato per generare una macchia riscaldamento grande (25 micron di diametro), minimizzare le gradienti di temperatura del campione sia radialmente che assialmente nella cella ad incudine di diamante, e massimizzare la stabilità riscaldamento. Figura 2 mostra schematicamentes della configurazione sperimentale per l&#39;esperimento laser-riscaldamento nella cella diamante-incudine con l&#39;immagine del punto laser-riscaldamento. </li><li> Allineare le incudini di diamante con 300 micron culets e preindent una guarnizione renio ad uno spessore di 30 micron da uno spessore iniziale di 250 micron. </li><li> Praticare un foro nella guarnizione preindented con un diametro di 120 micron al centro, e caricare il campione nel foro. </li><li> Pressurizzare il campione ad una pressione designata a temperatura ambiente, e poi riscaldare il campione aumentando la potenza del laser durante le misure di temperatura e in situ raggi X misure di diffrazione presso l&#39;impianto di sincrotrone. </li><li> Spegnere il laser per spegnere il campione quando la fusione parziale viene rilevata da un cambiamento di radiazione termica e dal modello di diffrazione. </li><li> Recuperare il campione riscaldato per la caratterizzazione ex situ. </li></ol> 4. Il recupero del campione e analisi <ol><li> Momentount il campione multi-incudine recuperato in resina epossidica e lucidare la superficie utilizzando una suite di polvere di graniglia diamante da 150 micron a 0,25 micron. </li><li> Carbon-rivestire la superficie del campione e caricarlo nell&#39;apposita camera di uno strumento trave Zeiss Auriga FIB / SEM (Figura 3A) per l&#39;analisi. </li><li> Allineare il campione nel punto coincidente della FIB e SEM a una distanza di lavoro di 5 mm (Figura 3B), e poi premill il campione per esporre un volume di 15 x 20 x 20 micron 3 (Figura 3C). </li><li> Prendere immagini SEM ad un intervallo di 25 nm, usando la fetta e funzione di visualizzazione sullo strumento Zeiss Auriga FIB / SEM (registrare automaticamente una serie di immagini dopo la fresatura fascio ionico con tipica risoluzione di immagine di circa 35 nm). </li><li> Inserire i file di dati immagine ad un software di visualizzazione e ricostruire immagini 3D per visualizzare la distribuzione di fusione e la connettività nel campione spento (Figura 3D). </li></ol>

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Nessun conflitto di interessi dichiarati.

Le tecniche per gli esperimenti multi-incudine sono ben stabiliti, generando pressione stabile e temperatura per un periodo di tempo di funzionamento prolungato e producendo relativamente grande volume di campione. Si tratta di un potente strumento per simulare i processi interni di pianeti, in particolare per gli esperimenti, come fusione di percolazione, che richiedono un certo volume di campione. La limitazione è la pressione massima raggiungibile, fino a 27 GPa con carburo di tungsteno (WC) incudini, raggiungendo l...

Pianeti terrestri, come la Terra, Venere, Marte e Mercurio sono corpi planetari differenziati costituiti da un mantello di silicati e di un nucleo metallico. Il moderno modello di formazione dei pianeti suggerisce che i pianeti terrestri sono formate da collisioni di embrioni planetari Luna-to-Mars-sized cresciute da chilometri di dimensioni o più grande planetesimi attraverso le interazioni gravitazionali 1-2. I planetesimi erano probabilmente già differenziati una volta che le leghe di ferro metalliche raggiunto temperatura di fusione a causa del riscaldamento da fonti come il decadimento radioattivo di isotopi a vita breve come 26 Al 60 Fe, impatto, e il rilascio di energia potenziale 3. È importante capire come il metallo liquido percolato attraverso una matrice di silicato durante la prima differenziazione. Pianeta differenziazione potrebbe procedere attraverso separazione liquido-liquido efficiente o per percolazione di metallo liquido in una matrice di silicato solido, a secondadelle dimensioni e della temperatura all&#39;interno degli organismi planetari. La percolazione di metallo liquido nella matrice di silicato solido è probabile un processo dominante nella differenziazione iniziale quando la temperatura non è sufficientemente elevata per fondere l&#39;intero corpo planetario. L&#39;efficienza di percolazione dipende dall&#39;angolo diedro, determinata dalle energie interfacciali delle interfacce solido-solido e solido-liquido. Possiamo simulare questo processo in laboratorio conducendo esperimenti ad alta pressione e ad alta temperatura su una miscela di lega di ferro e silicati. Recenti studi 4-7 hanno indagato la capacità bagnante di leghe di ferro liquido in una matrice di silicato solido ad alta pressione e temperatura. Hanno usato un metodo convenzionale per misurare la distribuzione di frequenza relativa di angoli diedri apparenti tra il metallo liquido da bonifica grani silicati sulle sezioni lucide per la determinazione del vero angolo diedro. Il metodo convenzionale produce relativamente grande uncertainties dell&#39;angolo diedro misurato e possibili distorsioni seconda delle statistiche di campionamento. Qui presentiamo una nuova tecnica di imaging per visualizzare la distribuzione del metallo liquido nella matrice di silicato in tre dimensioni (3D) mediante combinazione di fresatura FIB ed alta risoluzione emissione di campo dell&#39;imaging SEM. La nuova tecnica di imaging fornisce determinazione precisa dell&#39;angolo diedro e misura quantitativa della frazione volumetrica e la connettività della fase liquida. Il nucleo della Terra si è formata in un tempo relativamente breve (&lt;100.000 mila anni) 8, presumibilmente in uno stato liquido a sua storia antica. Marte e Mercurio hanno anche nuclei liquidi a base di deformazione di marea solare dai dati di rilevamento della radio Mars Global Surveyor 9 e modelli di radar speckle legati alla rotazione planetaria 10, rispettivamente. Modelli di evoluzione termica ed esperimenti di fusione ad alta pressione sulle materie fondamentali sostenere ulteriormente un nucleo marziano liquido11-12. Dati recenti Messenger veicoli spaziali forniscono ulteriori prove per un nucleo liquido di Mercurio 13. Anche la piccola Luna ha probabilmente un piccolo nucleo liquido a base di recente ri-analisi dei sismogrammi APPOLLO lunari 14. Nuclei planetari liquidi sono coerenti con alta energia di accrescimento nella fase iniziale della formazione dei pianeti. Successivo raffreddamento può portare alla formazione di nucleo interno solido per alcuni pianeti. Dati sismici hanno rivelato che la Terra è costituito da un nucleo esterno liquido e un solido interno. La formazione del nucleo interno ha importanti implicazioni per la dinamica del nucleo guidato da convezione termica e composizione e la generazione del campo magnetico del pianeta. Solidificazione del nucleo interno è controllata dalla temperatura di fusione dei materiali di base e l&#39;evoluzione termica del nucleo. Formazione del nucleo di pianeti terrestri condiviso percorsi di accrescimento simili e la composizione chimica dei nuclei è considerato abe dominato dal ferro con circa 10% in peso elementi leggeri quali zolfo (S), silicio (Si), ossigeno (O), carbonio (C) e idrogeno (H) 15. E &#39;essenziale avere conoscenza delle relazioni di fusione nei sistemi pertinenti al nucleo, come Fe-FeS, Fe-C, Fe-FeO, Fe-FEh e alta pressione-Fe FeSiat, al fine di comprendere la composizione i nuclei planetari. In questo studio, dimostreremo esperimenti condotti nel dispositivo multi-incudine e cella di diamante-incudine, simulando le condizioni dei nuclei planetari. Gli esperimenti forniscono informazioni sulla sequenza di cristallizzazione e elemento di partizionamento tra metallo solido e liquido, portando ad una migliore comprensione per le esigenze della cristallizzazione nucleo interno e la distribuzione degli elementi leggeri tra il nucleo interno cristallino e liquido fuori centro. Per estendere i rapporti di fusione a pressioni molto elevate, abbiamo sviluppato nuove tecniche per analizzare i campioni temprati recuperati da laser-riscaldato diamante-aesperimenti sulle cellule nvil. Con precisione FIB fresatura dello spot laser-riscaldamento, determiniamo fusione con criteri trama tempra ripreso con alta risoluzione di SEM e analisi chimica quantitativa con un rivelatore a deriva di silicio al submicron risoluzione spaziale. Qui delineare due serie di esperimenti per simulare la formazione di base planetaria da percolazione di metallica sciogliersi in matrice di silicato durante l&#39;accrescimento precoce e nucleo interno cristallizzazione successivo raffreddamento. La simulazione è volto a comprendere le due importanti processi durante l&#39;evoluzione del nucleo planetario.

<table><tbody><tr><td>Multi-anvil apparatus</td><td>Geophysical Lab</td><td>Home Builder</td><td> </td></tr><tr><td>Diamond-anvil cell</td><td>Geophysical Lab</td><td>Home Builder</td><td> </td></tr><tr><td>Laser-heating system</td><td>APS GSECARS</td><td>Designed by beamline staff</td><td> Public beamline</td></tr><tr><td>FIB/SEM Crossbeam</td><td>Carl Zeiss Ltd.</td><td>Auriga</td><td> </td></tr><tr><td>Avizo 3D software</td><td>VSG</td><td>Fire for materials science</td><td> </td></tr></tbody></table>

simulation of the planetary interior differentiation processes in the laboratory

Un interno planetario è in condizioni di alta pressione e ad alta temperatura ed ha una struttura a strati. Ci sono due importanti processi che hanno portato a tale struttura stratificata, (1) percolazione di metallo liquido in un solido matrice di silicato dalla differenziazione pianeta, e (2) cristallizzazione nucleo interno dalla successiva pianeta raffreddamento. Noi conduciamo esperimenti ad alta pressione e ad alta temperatura per simulare entrambi i processi in laboratorio. Formazione di percolativo nucleo planetario dipende dall&#39;efficienza di percolazione melt, che è controllata dal diedro (wetting) angolo. La simulazione percolazione comprende riscaldamento del campione ad alta pressione ad una temperatura obiettivo a cui lega di ferro-zolfo è fuso mentre il silicato rimane solido e quindi determinare il vero angolo diedro di valutare lo stile di migrazione liquido in una matrice cristallina da visualizzazione 3D. Il volume rendering 3D si ottiene tagliando il campione recuperato con un raggio di ioni focalizzati (FIB) e tare SEM immagine di ogni fetta con uno strumento trave FIB / SEM. La seconda serie di esperimenti è progettata per comprendere il nucleo di cristallizzazione e elemento distribuzione interna tra il nucleo esterno liquido e solido interno determinando la temperatura di fusione e elemento di partizionamento ad alta pressione. Gli esperimenti sono condotti in fusione dell&#39;apparato multi-incudine fino a 27 GPa ed estese a più alta pressione nella cella diamante-incudine con laser-riscaldamento. Abbiamo sviluppato tecniche per recuperare i piccoli campioni riscaldati con specificità FIB fresatura e ottenere immagini ad alta risoluzione dello spot laser-riscaldata che mostrano fusione struttura ad alta pressione. Analizzando la composizione chimica del liquido coesistenti e fasi solide, abbiamo appunto determinare la curva di liquidus, fornendo i dati necessari per comprendere il processo di cristallizzazione nucleo interno.

Abbiamo condotto una serie di esperimenti usando miscele di San Carlos olivina e lega metallica Fe-FeS con diversi rapporti metallo-silicati, come materiali di partenza. Il contenuto di S del metallo è del 10% in peso S. Qui vi mostriamo alcuni risultati rappresentativi da esperimenti ad alta pressione eseguiti a 6 GPa e 1.800 ° C, con ben calibrati gruppi multi-incudine 15. Nelle condizioni sperimentali, la lega metallica Fe-FeS è completamente fuso e il silicato (San Carlos olivina) rimane cristallina. L...

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Simulation of the Planetary Interior Differentiation Processes in the Laboratory

Gli esperimenti ad alta pressione e alta temperatura descritte qui imitano processi di differenziazione interni pianeta. I processi sono visualizzati e meglio compresi da alta risoluzione di immagini 3D e analisi chimica quantitativa.

Simulazione del Planetary Interior differenziazione processi in Laboratorio

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to ...

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Research

JoVE Journal

Engineering

11.5K Views.  Carnegie Institution of Washington.  Gli esperimenti ad alta pressione e alta temperatura descritte qui imitano processi di differenziazione interni pianeta. I processi sono visualizzati e meglio compresi da alta risoluzione di immagini 3D e analisi chimica quantitativa. 

Video: Simulation of the Planetary Interior Differentiation Processes in the Laboratory

Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

We present a technique to achieve low-velocity to intermediate-velocity collisions between fragile dust aggregates in the laboratory. For this purpose, two vacuum drop-tower setups have been developed that allow collision velocities between &#60;0.01 and ~10 m/sec. The collision events are recorded by high-speed imaging.

Laboratorio di goccia Torri per la simulazione sperimentale di collisioni Dust-aggregati nel sistema solare

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust ...

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Ingegneria

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

Simulazione Laboratorio di ferro (II) ricchi di Precambriano Marine Upwelling sistema per esplorare la crescita di batteri fotosintetici

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Ambiente

Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from their extraction to the core during terrestrial accretion. Experiments to investigate the partitioning of these elements between metal and silicate melts suggest that the PUM composition is best matched if metal-silicate equilibrium occurred at high pressures and temperatures, in a deep magma ocean environment. The behavior of the most highly siderophile elements (HSEs) during this process however, has remained enigmatic. Silicate run-products from HSE solubility experiments are commonly contaminated by dispersed metal inclusions that hinder the measurement of element concentrations in the melt. The resulting uncertainty over the true solubility and metal-silicate partitioning of these elements has made it difficult to predict their expected depletion in PUM. Recently, several studies have employed changes to the experimental design used for high pressure and temperature solubility experiments in order to suppress the formation of metal inclusions. The addition of Au (Re, Os, Ir, Ru experiments) or elemental Si (Pt experiments) to the sample acts to alter either the geometry or rate of sample reduction respectively, in order to avoid transient metal oversaturation of the silicate melt. This contribution outlines procedures for using the piston-cylinder and multi-anvil apparatus to conduct solubility and metal-silicate partitioning experiments respectively. A protocol is also described for the synthesis of uncontaminated run-products from HSE solubility experiments in which the oxygen fugacity is similar to that during terrestrial core-formation. Time-resolved LA-ICP-MS spectra are presented as evidence for the absence of metal-inclusions in run-products from earlier studies, and also confirm that the technique may be extended to investigate Ru. Examples are also given of how these data may be applied.

We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

Partizionamento metallo-silicato ad alta pressione e temperatura: metodi sperimentali e un protocollo per sopprimere altamente Siderophile Element Inclusioni

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from ...

Chimica

Chemical Gardens as Flow-through Reactors Simulating Natural Hydrothermal Systems

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment allows for testing of various proposed ocean / hydrothermal fluid chemistries that could have driven reactions toward the origin of life in environments on the early Earth, early Mars, or even other worlds such as the icy moons of the outer planets. We show experiments that include growth of chemical garden structures under anoxic conditions simulating the early Earth, inclusion of trace components of phosphates / organics in the injection solution to incorporate them into the structure, a switch of the injection solution to introduce a secondary precipitating anion, and the measurement of membrane potentials generated by chemical gardens. Using this method, self-assembling chemical garden structures were formed that mimic the natural chimneys precipitated at submarine hydrothermal springs, and these precipitates can be used successfully as flow-through reactors by feeding through multiple successive &#8220;hydrothermal&#8221; injections.

We describe chemical garden formation via injection experiments that allow for laboratory simulations of natural chemical garden systems that form at submarine hydrothermal vents.

Giardini chimici come flusso attraverso Reattori simulando naturali idrotermali Sistemi

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment ...

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

Earth-abundant minerals play important roles in the natural hydrothermal systems. Here, we describe a reliable and cost-effective method for the experimental investigation of organic-mineral interactions under hydrothermal conditions.

Un protocollo sperimentale per lo studio di minerali effetti sulle trasformazioni organiche idrotermale

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the ...

Atom Probe Tomography Analysis of Exsolved Mineral Phases

Element diffusion rates and temperature/pressure control a range of fundamental volcanic and metamorphic processes. Such processes are often recorded in lamellae exsolved from host mineral phases. Thus, the analysis of the orientation, size, morphology, composition and spacing of exsolution lamellae is an area of active research in the geosciences. The conventional study of these lamellae has been conducted by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and more recently with focused ion beam (FIB)-based nanotomography, yet with limited chemical information. Here, we explore the use of atom probe tomography (APT) for the nanoscale analysis of ilmenite exsolution lamellae in igneous titanomagnetite from ash deposits erupted from the active Soufri&#232;re Hills Volcano (Montserrat, British West Indies). APT allows the precise calculation of interlamellar spacings (14&#8211;29 &#177; 2 nm) and reveals smooth diffusion profiles with no sharp phase boundaries during the exchange of Fe and Ti/O between the exsolved lamellae and the host crystal. Our results suggest that this novel approach permits nanoscale measurements of lamellae composition and interlamellar spacing that may provide a means to estimate the lava dome temperatures necessary to model extrusion rates and lava dome failure, both of which play a key role in volcanic hazard mitigation efforts.

Analysis of the morphology, composition, and spacing of exsolution lamellae can provide essential information to understand geological processes related to volcanism and metamorphism. We present a novel application of APT for the characterization of such lamellae and compare this approach to the conventional use of electron microscopy and FIB-based nanotomography.

Analisi tomografia atomo sonda delle fasi minerali essolte

Element diffusion rates and temperature/pressure control a range of fundamental volcanic and metamorphic processes. Such processes are often recorded in ...

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 &#176;C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperature&#160;gradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.

The goal of this protocol is to form simulated hydrothermal chimneys via chemical garden injection experiments and introduce a thermal gradient across the inorganic precipitate membrane, using a 3D printable condenser that can be reproduced for educational purposes.

Simulazione di camini idrotermali della Terra primordiale in un ambiente a gradiente termico

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the ...

Simulating Temperature in a Soil Incubation Experiment

The study of warming impact on soils requires a realistic and accurate representation of temperature. In laboratory incubation studies, a widely adopted method has been to render constant temperatures in multiple chambers, and via comparisons of soil responses between low- and high-temperature chambers, to derive the warming impact on soil changes. However, this commonly used method failed to imitate both the magnitude and amplitude of actual temperatures as observed in field conditions, thus potentially undermining the validity of such studies. With sophisticated environmental chambers becoming increasingly available, it is imperative to examine alternative methods of temperature control for soil incubation research. This protocol will introduce a state-of-the-art environmental chamber and demonstrate both conventional and new methods of temperature control to improve the experimental design of soil incubation. The protocol mainly comprises four steps: temperature monitoring and programming, soil collection, laboratory incubation, and warming effect comparison. One example will be presented to demonstrate different methods of temperature control and the resultant contrasting warming scenarios; that is, a constant temperature design referred to as stepwise warming (SW) and simulated in situ temperature design as gradual warming (GW), as well as their effects on soil respiration, microbial biomass, and extracellular enzyme activities. In addition, we present a strategy to diversify temperature change scenarios to meet specific climate change research needs (e.g., extreme heat). The temperature control protocol and the recommended well-tailored and diversified temperature change scenarios will assist researchers in establishing reliable and realistic soil incubation experiments in the laboratory.

Laboratory soil warming experiments usually employ two or more constant temperatures in multiple chambers. By presenting a sophisticated environmental chamber, we provide an accurate temperature control method to imitate the magnitude and amplitude of in situ soil temperature and improve the experimental design of soil incubation studies.

Simulazione della temperatura in un esperimento di incubazione del suolo

The study of warming impact on soils requires a realistic and accurate representation of temperature. In laboratory incubation studies, a widely adopted ...

Measuring Electrical Conductivity to Study the Formation of Brines Under Martian Conditions

This paper describes a protocol to design experiments to study the formation of brines under Martian conditions and monitor the process with electrical conductivity measurements. We used the Engineering Qualification Model (EQM) of Habitability: Brines, Irradiation, and Temperature (HABIT)/ExoMars 2022 instrument for the experiment setup but we provide a brief account of constructing a simple and inexpensive electrical conductivity measurement setup. The protocol serves to calibrate the electrical conductivity measurements of the salt deliquescence into brine in a simulated Martian environment. The Martian conditions of temperature (-70 &#176;C to 20 &#176;C), relative humidity (0% to 100%) and pressure (7 - 8 mbar) with carbon-dioxide atmosphere were simulated in the SpaceQ Mars simulation chamber, a facility at the Lule&#229; University of Technology, Sweden. The hydrate form of the known amount of salt accommodated between a pair of electrodes and thus the electrical conductivity measured depends predominantly on its water content and the temperature and relative humidity of the system. Electrical conductivity measurements were carried out at 1 Hz while exposing salts to a continuously increasing relative humidity (to force transitioning through various hydrates) at different Martian temperatures. For demonstration, a day-night cycle at Oxia Planum, Mars (the landing site of ExoMars 2022 mission) was recreated.

The objective of the protocol is to monitor the hydration of salts and the brine formation process. Electrical conductivity is used as the measurement technique. The experiments are performed in a simulated Martian environment of temperature, relative humidity and carbon-dioxide atmosphere.

This paper describes a protocol to design experiments to study the formation of brines under Martian conditions and monitor the process with electrical ...

Surrogate Model Development for Digital Experiments in Welding

The manufacturing industry heavily relies on welding processes to join materials, forming integral components across various sectors. Many aspects will influence the quality of the weld and finally affect the structure integrity of the weldment. Welding-induced residual stress, a consequence of the thermal cycling inherent in these processes, significantly impacts the structural integrity and performance of fabricated components. Understanding and predicting this residual stress is crucial for enhancing the reliability and durability of welded structures. However, quickly assessing a welding setup in digital experiments presents significant challenges, as a traditional simulation may be time-consuming. This research outlines the application of a workflow to construct an artificial neural network-based surrogate model to predict welding-induced residual stress. The model is built using data automatically generated from finite element simulations through Python scripts based on macro functions. Unlike traditional methods that rely on manual preprocessing and finite element simulations, this approach significantly reduces the time and effort required for simulation setup and data extraction, enhancing overall efficiency. By ensuring that all simulation steps are performed consistently through macro functions, the method eliminates human-induced variability, leading to improved reproducibility. Furthermore, the automation of data generation makes it possible to create extensive datasets necessary for training machine learning models, overcoming the limitations of labor-intensive traditional techniques. The workflow contains four main steps: build a standard weld finite element simulation and validate the finite element simulation results against experimental data; develop scripts for large dataset generation using a macro function that records the preprocessing and postprocessing steps of the finite element simulation; use the scripts to generate the required data; develop surrogate models and test their performance. The artificial neural network demonstrated high accuracy in predicting stress levels, closely aligning with simulation results on the test dataset and a relative root mean square error of 0.0024.

This protocol outlines a general workflow for constructing an artificial neural network for welding simulation using datasets generated automatically through Python scripts with macro functions. The workflow is validated against a benchmark case involving single-pass, straight-line welding. The surrogate model's predictive accuracy shows a strong agreement with finite element simulations.

Sviluppo di modelli surrogati per esperimenti digitali nella saldatura

The manufacturing industry heavily relies on welding processes to join materials, forming integral components across various sectors. Many aspects will ...