This study is dedicated to the memory of Prof. Harry W. Green, without whom none of this would have been possible. We also thank J&#246;rg Renner and S&#233;bastien Sanchez for their implications in designing and implementing the apparatus, as well as Andreas K. Kronenberg, Caleb W. Holyoke III and three anonymous reviewers for their fruitful discussions and comments. We are grateful to Jan Tullis for teaching us and numerous students the basics and many useful tricks of solid-medium deformation experiments. This study has been funded by the ERC RHEOLITH (grant 290864), Labex Voltaire (ANR-10-LABX-100-01), Equipex PlaneX (ANR-11-EQPX-0036) and ANR DELF (ANR-12-JS06-0003).

<ol>
	<li>Le Pichon, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sea-Floor+Spreading+and+Continental+Drift.">Sea-Floor Spreading and Continental Drift.</a> J. Geophys. Res. 73 (12), 3661-3697 (1968).</li><li>Buck, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modes+of+continental+Lithospheric+Extension.">Modes of continental Lithospheric Extension.</a> J. Geophys. Res. 96 (B12), 20161-20178 (1991).</li><li>Bercovici, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+generation+of+plate+tectonics+from+mantle+convection.">The generation of plate tectonics from mantle convection.</a> EPSL. 205 (3-4), 107-121 (2003).</li><li>Frederiksen, S., Braun, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+modelling+of+strain+localisation+during+extension+of+the+continental+lithosphere.">Numerical modelling of strain localisation during extension of the continental lithosphere.</a> EPSL. 188 (1-2), 241-251 (2001).</li><li>Gueydan, F., Morency, C., Brun, J. -. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continental+rifting+as+a+function+of+lithosphere+mantle+strength.">Continental rifting as a function of lithosphere mantle strength.</a> Tectonophysics. 460 (1-4), 83-93 (2008).</li><li>Burov, E. B., Watts, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+long-term+strength+of+the+continental+lithosphere:+"Jelly+sandwich"+or+"cr&#232;me+br&#251;l&#233;e".">The long-term strength of the continental lithosphere: "Jelly sandwich" or "cr&#232;me br&#251;l&#233;e".</a> GSA today. 16 (1), 4-10 (2006).</li><li>Tackey, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mantle+Convection+and+Plate+Tectonics:+Toward+an+Integrated+Physical+and+Chemical+Theory.">Mantle Convection and Plate Tectonics: Toward an Integrated Physical and Chemical Theory.</a> Science. 288 (5473), 2002-2007 (2000).</li><li>Paterson, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-pressure,+high-temperature+apparatus+for+rock+deformation.">A high-pressure, high-temperature apparatus for rock deformation.</a> Int. J. Rock Mec. Min. Sci. Geomec. Abs. 7 (5), 517-524 (1970).</li><li>Griggs, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrolytic+weakening+of+quartz+and+other+silicates.">Hydrolytic weakening of quartz and other silicates.</a> Geophys. J. Int. 14 (1-4), 19-31 (1967).</li><li>Tullis, T. E., Tullis, J., Hobbs, B. E., Heard, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Rock+Deformation+Techniques.">Experimental Rock Deformation Techniques.</a> Mineral and Rock Deformation: Laboratory Studies: The Paterson Volume. Geophys. Mono. Series. 36, 297-324 (1986).</li><li>Green, H. W., Borch, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+New+Molten+Salt+Cell+for+Precision+Stress+Measurements+at+High+Pressure.">A New Molten Salt Cell for Precision Stress Measurements at High Pressure.</a> Eur. J. Mineral. 1 (2), 213-219 (1989).</li><li>Wang, Y., Durham, W. B., Getting, I. C., Weidner, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+deformation-DIA:+A+new+apparatus+for+high+temperature+triaxial+deformation+to+pressures+up+to+15+GPa.">The deformation-DIA: A new apparatus for high temperature triaxial deformation to pressures up to 15 GPa.</a> Rev. Sci. Instrum. 74, 3002-3011 (2003).</li><li>Kawazoe, T., Ohuchi, T., Nishiyama, N., Nishihara, Y., Irifune, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preliminary+deformation+experiment+of+ringwoodite+at+20+GPa+and+1700+K+using+a+D-DIA+apparatus.">Preliminary deformation experiment of ringwoodite at 20 GPa and 1700 K using a D-DIA apparatus.</a> J. Earth. Sci. 21 (5), 517-522 (2010).</li><li>Nomura, R., Azuma, S., Uesugi, K., Nakashima, Y., Irifune, T., Shinmei, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-pressure+rotational+deformation+apparatus+to+135+GPa.">High-pressure rotational deformation apparatus to 135 GPa.</a> Rev. Sci. Instrum. 88 (4), 044501 (2017).</li><li>Holyoke, C. W., Kronenberg, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+differential+stress+measurement+using+the+molten+salt+cell+and+solid+salt+assemblies+in+the+Griggs+apparatus+with+applications+to+strength,+piezometers+and+rheology.">Accurate differential stress measurement using the molten salt cell and solid salt assemblies in the Griggs apparatus with applications to strength, piezometers and rheology.</a> Tectonophysics. 494 (1-2), 17-31 (2010).</li><li>Kido, M., Muto, J., Nagahama, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+correction+of+differential+stress+calculations+from+experiments+using+the+solid+salt+assembly+in+a+Griggs-type+deformation+apparatus.">Method for correction of differential stress calculations from experiments using the solid salt assembly in a Griggs-type deformation apparatus.</a> Tectonophysics. 672-673, 170-176 (2016).</li><li>Mei, S., Suzuki, A. M., Kohlstedt, D. L., Dixon, N. A., Durham, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+constraints+on+the+strength+of+the+lithospheric+mantle.">Experimental constraints on the strength of the lithospheric mantle.</a> J. Geophys. Res. 115, B08204 (2010).</li><li>Gleason, G. C., Tullis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+flow+law+for+dislocation+creep+of+quartz+aggregates+determined+with+the+molten+salt+cell.">A flow law for dislocation creep of quartz aggregates determined with the molten salt cell.</a> Tectonophysics. 247 (1-4), 1-23 (1995).</li><li>Rybacky, E., Renner, J., Konrad, K., Harbott, W., Rummel, F., St&#246;ckhert, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Servohydraulically-controlled+Deformation+Apparatus+for+Rock+Deformation+under+Conditions+of+Ultra-high+Pressure+Metamorphism.">A Servohydraulically-controlled Deformation Apparatus for Rock Deformation under Conditions of Ultra-high Pressure Metamorphism.</a> PAGEOPH. 152, 579-606 (1998).</li><li>Zhang, J., Green, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Investigation+of+Eclogite+Rheology+and+Its+Fabrics+at+High+Temperature+and+Pressure.">Experimental Investigation of Eclogite Rheology and Its Fabrics at High Temperature and Pressure.</a> J. Metam. Geol. 25 (2), 97-115 (2007).</li><li>Groenback, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+stripwound+tools+in+high+and+low+volume+cold-forging+production,+(7th+Int.+Cold+Forging+Congress,+Birmingham+1985).">Application of stripwound tools in high and low volume cold-forging production, (7th Int. Cold Forging Congress, Birmingham 1985).</a> Drahtwelt. 72, 10-11 (1985).</li><li>Li, Z., Li, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melting+curve+of+NaCl+to+20+GPa+from+electrical+measurements+of+capacitive+current.">Melting curve of NaCl to 20 GPa from electrical measurements of capacitive current.</a> Am. Min. 100 (8-9), 1892-1898 (2015).</li><li>Pr&#233;cigout, J., St&#252;nitz, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+of+phase+nucleation+during+olivine+diffusion+creep:+A+new+perspective+for+mantle+strain+localization.">Evidence of phase nucleation during olivine diffusion creep: A new perspective for mantle strain localization.</a> EPSL. 455, 94-105 (2016).</li><li>Heilbronner, R., Tullis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+c+axis+pole+Figures+and+grain+size+during+dynamic+recrystallization:+Results+from+experimentally+sheared+quartzite.">Evolution of c axis pole Figures and grain size during dynamic recrystallization: Results from experimentally sheared quartzite.</a> J. Geophys. Res. 111, B10202 (2006).</li><li>Blacic, J. D., Hagman, R. 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The authors have nothing to disclose.

Initially, the Griggs-type apparatus was designed to perform deformation experiments as slowly as possible to approach geological strain rates closer than other techniques, i.e., over weeks, months or even years9. Thus, Griggs-type experiments may run as long as the electrical supply and water cooling are functioning, particularly overnight when no operator is required. As mentioned before, the Griggs press can also explore most of the range of pressure and temperature encountered in the lithosphere. However, this technique presently is subjected to some limitations that may reduce the accuracy of the stress determination.
The success of a Griggs-type experiment relies on several critical points that mainly include the quality of the thermocouple sheath, the shape of packing rings, and the alignment of shear pistons (only for general shear experiments). Indeed, the thermocouple wires should be well insulated from each other and from the confining medium (NaCl). Otherwise, the temperature recording may be either modified through touching of the two wires outside of the sample chamber, leading to a dramatic increase of temperature (this could break the pressure vessel), or the thermocouple may break and the experiment fails. The top surface of each packing ring (&#963;1 and &#963;3) should be flat and large enough (around half a millimeter). This is required to avoid any lead leak during pressure increase. For general shear experiments, the top and bottom shear pistons should be perfectly aligned, so that no asymmetrical deformation occurs during experiment. If not, the sample may come into contact with the confining medium through a jacket leak, giving rise to possible contamination and sample failure. In addition, such a jacket leak will likely occur in a general shear experiment if the deformation piston is not stopped early enough. The capability of the platinum jacket in being deformed without any breaking may significantly vary from one experiment to another. Nevertheless, although shear deformation has been already achieved at more than gamma = 7 on samples of 2 mm thickness (an example is given in Heilbronner and Tullis24), a gamma = 5 is routinely applied with a good success rate and significantly higher shear strains can be achieved by reducing the sample thickness.
Nowadays, the Griggs press is subject to friction effects that reduce the accuracy of stress measurements, particularly when the &#34;hit point&#34; is defined by curve fitting. Most of the friction occurs while the deformation piston is advancing through the &#963;1 packing ring, lead piece and confining medium (NaCl). This can be seen from the stress-time curve during the &#34;run-in&#34; step of the deformation stage (Figure 9), but also during loading after the hit point. While elastic behavior is not dependent on the sample stiffness, the slope of the loading curve increases with the sample strength in the Griggs-type apparatus. This is mainly due to non-elastic sample strain while the &#963;1 piston pushes through the lead. Indeed, the slope of the load curve before yield stress conditions does not represent pure elastic loading of the sample, but a combination of different components that include friction and some sample deformation/compaction. Unfortunately, this type of behavior is hardly reproducible as it depends on the sample strength, which is low at high temperature, and the error induced by friction that strongly varies from 3 to 9%18. Some other weaker materials like Indium, Bismuth or Tin have been used instead of lead19, but they always give rise to some leak at pressures higher than 1 GPa. In addition, whereas km-scale objects and very slow strain rates (10-15-10-12 s-1) need to be considered for geological purposes, the Griggs-type apparatus - like any other deformation apparatus - is limited in terms of sample size (max. 8 mm diameter for the Griggs press) and strain rate (min. 10-8 s-1). These geological conditions require indeed unrealistic forces and impractical duration of experiment to be applied. Nevertheless, this inevitable gap between deformation experiments and geological circumstances may be partly substituted by numerical models, provided that lab-based mechanical laws are fully valid through extrapolations. This definitely requires developing high-pressure apparatuses with better accuracy, at least as good as the one of the gas-pressure-medium-type apparatus (i.e., &#177; 1 MPa).
At present, only the gas-medium apparatuses are accurate enough to perform rheological experiments, and most of the available mechanical laws come from the Paterson apparatus at confining pressure of 0.3 GPa. The high accuracy on stress measurements mainly relies on the presence of an internal load cell that undergoes the confining pressure, in contrast to an external one that only suffers room pressure, and its combination with a gas pressure vessel, which permitted to apply a specific design that cannot be transferred as-is into a solid-medium press. Today, the solid-medium apparatus only uses an external load cell &#8211; some of them do not even have any load cell &#8211; to measure the differential stress, giving rise to a poor resolution and substantial overestimation because of friction.
In the Griggs-type apparatus, the using of a molten salt assembly may significantly reduce the friction around the sample (by a factor of 3). But as mentioned before, it also gives rise to further issues and the accuracy of stress measurement remains 10 times lower than that in the Paterson apparatus. Another approach would consist in implementing an internal load cell, or something similar, to get rid of the friction effects in the Griggs press. Considering the size and capacities of &#34;regular&#34; load cells, such as found in the industry, it seems unrealistic to include some of them within the sample chamber of the pressure vessel. They could not sustain the confining pressure and a high-capacity load cell (max. 200 kN), such as required for high-pressure experiments in the Griggs-type apparatus, and they would be too large to be included in the sample chamber. However, one possibility would imply using the basal piston of the sample column as an internal load cell25, provided that its deformation can be precisely measured (Andreas K. Kronenberg, personal communications). This requires a room below the base plate to adapt a specific load cell, which has been anticipated in the new Griggs-type apparatus (Figure 1). But today, such an internal load cell in solid-medium deformation apparatus remains to be implemented.

Rock deformation is one of the most important geological processes. It strongly contributes to human-time-scale phenomena, like earthquakes or landslides, but also to the large-scale mass movements of the solid outer shell in telluric planets, including plate tectonics on Earth1. For instance, depending on the rheology of the shell-like lithosphere, which defines the strength of both the crust and sub-solidus mantle (<img alt="Equation" src="/files/ftp_upload/56841/56841eq1.jpg" /> 1200 &#176;C), the scheme of plate tectonics and related features may vary significantly2,3,4,5. On the one hand, the presence of a strong uppermost mantle and/or lower crust is required to sustain mountain belts or stabilize subduction zones6. But on the other hand, numerical models have also shown that plate boundaries cannot develop from mantle convection if the lithosphere is too strong, giving rise to a rigid lid behavior as observed on Venus7. Thus, the strength of the lithosphere as dictated by rock rheology has a direct control on the plate-like behavior of active planets.
For more than half a century, the rock rheology has been investigated at high temperatures (&#62; 300 &#176;C), giving rise to state-of-the-art techniques that mainly differ in the pressure range they can achieve. This includes the gas-medium Paterson-type apparatus8 at relatively low pressures (&#60;0.5 GPa), the solid-medium Griggs-type apparatus9,10,11 at intermediate to high pressures (0.5-5 GPa), and the deformation-Dia apparatus12,13 (DDia: up to ~20 GPa) or diamond anvil cell at very high pressures14 (up to more than 100 GPa). Thus, the pressures and temperatures encountered in the deep Earth can nowadays be achieved experimentally. However, rock deformation also relies on differential stress that needs to be measured with high accuracy and precision, so that constitutive relationships can be formulated. Thanks to its gas-confining medium, the Paterson apparatus is today the only technique able to perform stress measurements with an adequate accuracy (&#177; 1 MPa) to extrapolate the data over 6 orders of magnitude in strain rate, but it can only explore deformation processes at low pressures. Conversely, solid-medium apparatuses can deform rocks at high pressures, but with a lower accuracy of the stress measurements. While stress accuracy has been estimated at &#177; 30 MPa for the Griggs-type apparatus15,16, the synchrotron-based DDia produces mechanical laws with an error of more than &#177; 100 MPa17. In the Griggs-type apparatus, stress could also be overestimated by up to 36% with respect to stress measurements in the Paterson one15. Performing accurate and precise stress measurements at high pressures - and high temperatures - therefore remains a major challenge in Earth Sciences.
Excluding deep subduction slabs where pressures may exceed 5 GPa, the Griggs-type apparatus is presently the more appropriate technique to study deformation processes over the pressure (&#60; 4 GPa) and temperature (<img alt="Equation" src="/files/ftp_upload/56841/56841eq1.jpg" /> 1200 &#176;C) ranges in a large part of the lithosphere. On this basis, significant endeavors have been undertaken in the 1990&#39;s to improve stress measurements, particularly to reduce friction effects by using eutectic salt mixtures as a confining medium around the sample11,18. Such a molten salt assembly gave rise to a better accuracy of the stress measurement, reducing the error from &#177; 30 to &#177; 10 MPa15,19, but additional disadvantages have been encountered when applying this type of assembly. These have a much lower success rate, great difficulties to perform non-coaxial (shear) experiments, and a more complicated sample assembly. Moreover, the accuracy of stress measurements remains ten times lower than that of the low-pressure Paterson-type apparatus. These issues limit the quantification of rheological processes using the Griggs-type apparatus, which today is more commonly applied to explore the deformation processes and their related microstructures. A new approach will be therefore required to perform rheological quantification at high lithospheric pressures.
This paper gives detailed documentation of the &#34;conventional&#34; procedure to perform high-pressure deformation experiments using a newly designed solid-medium Griggs-type apparatus. In the framework of new &#34;Griggs&#34; laboratories implemented at the ISTO (Orl&#233;ans, France) and ENS (Paris, France), the main purpose is to properly illustrate each step of the protocol in details, so that scientists from all fields can decide whether the apparatus is appropriate or not to their aims of study. The critical steps and limitations of this state-of-the-art technique are also discussed, together with new approaches and possible future developments.
The new Griggs-type apparatus
Based on the piston-cylinder technology, the Griggs-type apparatus has been formerly designed by David T. Griggs in the 1960&#39;s9, and then modified by Harry W. Green in the 1980&#39;s11 (mainly to achieve higher pressures during deformation experiments). In both cases, the Griggs apparatus is characterized by a metal frame that includes: 1) three horizontal platens mounted on vertical columns, 2) a main hydraulic cylinder (confining pressure ram) suspended to the middle platen and 3) a deformation gear box and piston/actuator fixed on top of the upper platen (Figure 1). The &#34;confining&#34; ram and deformation actuator are each connected to independent pistons that transmit forces to the sample assembly within a pressure vessel. With such a vessel, deformation can be achieved at confining pressures of up to 2 or 5 GPa, depending on the apparatus and diameter of the sample assembly.
Thanks to a resistance furnace, the sample temperature is increased by Joule effect (up to &#8776;1300 &#176;C20), while the pressure vessel is water cooled on top and bottom. In Green&#39;s design, the Griggs apparatus also includes an end-load system that homogenizes the pre-stress in the pressure vessel (Figure 1). This permits to achieve deformation experiments at higher pressures (max. 5 GPa), particularly using a small bore in the pressure vessel. For further details about the Griggs press, the readers are referred to the excellent description of the modified Griggs apparatus design by Rybacky et al.19.
Arising from a close collaboration between the Institut des Sciences de la Terre d&#39;Orl&#233;ans (ISTO, France) and &#201;cole Normale Sup&#233;rieure de Paris (ENS Paris, France), the new generation Griggs-type apparatus is directly based on the design from H. W. Green11, but some improvements have been made to comply with European standards for safety of high-pressure experiments. In this new press, the confining and deformation actuators are driven by servo-controlled hydraulic syringe pumps, giving the possibility to perform either constant load or constant displacement experiments at high pressures (up to 5 GPa). The confining (isostatic) pressure, force, and displacement are respectively monitored using oil pressure sensors, a load cell (max. 200 kN) and displacement transducers (Figure 1). The pressure vessel is made of an inner tungsten-carbide (WC) core inserted into a 1&#176; conical steel ring and pre-stressed using the strip winding technique21. For transmitting forces, the pressure vessel and sample assembly lie between WC-removable pistons that include a deformation piston (&#963;1), confining piston (&#963;3), end-load piston and base plate (Figure 1). Together with regular cooling on top and bottom of the pressure vessel, water flows through the steel vessel around the tungsten-carbide core within 6 mm diameter holes for better cooling (Figure 1). The hydraulic cylinder for the confining pressure is also cooled by silicon oil flow. In addition, the deformation apparatus in Orl&#233;ans employs larger sample size up to 8 mm diameter, so that 1) microstructures can be better developed, and 2) the Griggs press and Paterson press share a common sample dimension for future comparisons. This requires an increased diameter of the WC bore in the pressure vessel (27 mm, instead of 1 inch, i.e., 25.4 mm), reducing the maximum attainable pressure to 3 GPa.
The present paper describes the procedure to perform an experiment with the new Griggs-type apparatus, which includes the description of all pieces that compose the conventional solid-salt sample assembly using alumina pistons (Figure 2A and 2B), as well as the successive steps to produce them and introduce them into the pressure vessel. This description follows in large parts the routine developed over many years by Prof. Jan Tullis and co-workers at Brown University (R.I., USA). The resulting sample assembly is fully appropriate to perform either co-axial (pure shear) or non-coaxial (general shear) deformation experiments over the whole range of pressures and temperatures of the Griggs-type apparatus. While a pure shear experiment typically requires a cored drill sample of a certain length (commonly &#8776;2 times the sample diameter), a general shear deformation is commonly applied to a zone cut at 45&#176; to the piston axis (Figure 2B). The sample material can either be a slice of a core sample or fine-grained powder of a chosen grain size. All pieces are wrapped into a metal foil and jacketed within a platinum tube welded (or folded flat) at both sides. The temperature is commonly monitored using either S-type (Pt90%Rd10% alloy) or K-type (Ni alloy) thermocouple, but only the preparation of an S-type thermocouple using a mullite 2-hole sheathing tube is here described (Figure 2C).

<table border="0" cellpadding="0" cellspacing="0" width="1347">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Griggs-type apparatus</td>
			<td style="width:237px;">Sanchez Technologies (Corelab)</td>
			<td style="width:236px;">TRI-X 6/1500 SD</td>
			<td style="width:659px;">Solid-medium Griggs-type deformation apparatus</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;"></td>
			<td style="width:237px;">Sanchez Technologies (Corelab)</td>
			<td style="width:236px;">Stigma pumps 1000/300 and 100/1500</td>
			<td>hydraulic syringe pumps to apply pressure</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Arbor press</td>
			<td style="width:237px;">Schiltz</td>
			<td style="width:236px;">PA.WZ.5000.530</td>
			<td>Arbor press required to insert the sample assembly into the pressure vessel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Low-speed saw</td>
			<td style="width:237px;">Presi</td>
			<td style="width:236px;">Mecatome T180</td>
			<td>Law-speed saw to cut alumina piston and mullite sheath</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Presi</td>
			<td style="width:236px;">LR02033</td>
			<td>Diamond saw blade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">40 tons hydraulic press</td>
			<td style="width:237px;">CompaC</td>
			<td style="width:236px;">APA 9040EH1-D</td>
			<td>40-ton hydraulic press to press salt/lead pieces and extract the sample</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pressure vessel (and pistons)</td>
			<td style="width:237px;">STRECON</td>
			<td>vessel A4071&#160;</td>
			<td>Inner tungsten-carbide core inserted into a 1&#176; conical steel ring and pre-stressed using the strip winding technique</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">STRECON</td>
			<td>Deformation piston</td>
			<td>Tungsten carbide piston to apply deformation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">STRECON</td>
			<td>Confining piston</td>
			<td>Tungsten carbide piston to apply confining pressure</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">STRECON</td>
			<td>End-load piston</td>
			<td>Tungsten carbide piston to pre-stress the pressure vessel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PUK U3</td>
			<td style="width:237px;">Lampert</td>
			<td style="width:236px;">PUK 5 welding microscope</td>
			<td>Fine welding system to weld the thermocouple and platinum jacket</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cooling system Ultracool</td>
			<td style="width:237px;">Lauda</td>
			<td style="width:236px;">UC 4 E1 PI5 SR BSP &#176;C</td>
			<td>Cooler for the pressure vessel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Lauda</td>
			<td style="width:236px;">Proline RP850</td>
			<td>Cooler for the confining/end-load ram</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Leath</td>
			<td style="width:237px;">Schneider electric</td>
			<td style="width:236px;">Eurotherm 2704</td>
			<td>Temperature controller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Milling machine</td>
			<td style="width:237px;">Enerpac</td>
			<td style="width:236px;">P-142</td>
			<td>Hand pump to lift up the confining/end-load ram</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM</td>
			<td style="width:236px;">1-P3TCP/2000 bar</td>
			<td style="width:659px;">Pressure transducer</td>
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			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM</td>
			<td style="width:236px;">1-P3TCP/500 bar</td>
			<td style="width:659px;">Pressure transducer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM</td>
			<td style="width:236px;">WA/10 mm</td>
			<td style="width:659px;">Displacement transducer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM</td>
			<td style="width:236px;">WA/50 mm</td>
			<td style="width:659px;">Displacement transducer</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM&#160;</td>
			<td style="width:236px;">1-C2/200 kN</td>
			<td>Load cell</td>
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			<td style="width:237px;">Geoscience instrument</td>
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			<td>Graphite furnace: graphite tube inserted between two pyrophyllite sleeves (custom-made)</td>
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			<td>MRD028330018858</td>
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			<td style="width:237px;">NSK</td>
			<td style="width:236px;">EM-255</td>
			<td>Diamond tool to parallelize alumina piston using the lathe</td>
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			<td style="width:237px;">Mecanelec</td>
			<td style="width:236px;">CDM &#8211; IP 1 &#8211; 5L/mn</td>
			<td>Flow meter for water cooling (pressure vessel)</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Hedland</td>
			<td style="width:236px;">H602A-0005-F1</td>
			<td>Flow meter for oil cooling (confining/end-load ram)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Legris</td>
			<td style="width:236px;">S&#233;rie 21</td>
			<td>double-self-sealing coupler for tube of the water cooling system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Corelab</td>
			<td style="width:236px;">Falcon</td>
			<td>Software to monitor the hydraulic syringe pumps</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">HBM</td>
			<td style="width:236px;">CatmanEasy-HP</td>
			<td>Software to record data</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Schneider electric</td>
			<td style="width:236px;">Eurotherm itools</td>
			<td>Software to set programs for the temperature controller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">VWR</td>
			<td style="width:236px;">410-0114</td>
			<td>Ceramic mortar</td>
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		<tr height="21">
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			<td style="width:237px;">VWR</td>
			<td style="width:236px;">231-2322</td>
			<td>Microspatule</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">VWR</td>
			<td style="width:236px;">459-0206</td>
			<td>Ceramic recipient</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">VWR</td>
			<td style="width:236px;">AnalaR NORMAPUR 27810.364</td>
			<td>Sodium Chloride 99.9% purity</td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;"></td>
			<td style="width:237px;">VWR</td>
			<td style="width:236px;">Barnstead/Thermoline 48000 furnace</td>
			<td>Benchtop Muffle furnace for melting lead</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">DP/Pr&#233;cision</td>
			<td style="width:236px;">Custom made</td>
			<td>Tools needed to produce the salt and lead pieces</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Cincinnati</td>
			<td style="width:236px;">TYPE PE-5</td>
			<td>Milling machine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Memmert</td>
			<td style="width:236px;">UNB 400</td>
			<td>Oven to stock salt powder and salt pieces</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Otelo</td>
			<td style="width:236px;">Otelo 65220023</td>
			<td>Tubing cutter for Platinum</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Otelo</td>
			<td style="width:236px;">BAITER 51600202</td>
			<td>File tool</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Otelo</td>
			<td style="width:236px;">VADIUM 65172600</td>
			<td>Diagional micro-cutter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Otelo</td>
			<td style="width:236px;">VADIUM 65172620</td>
			<td>Flat needle nose micro-pliers</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">SAM</td>
			<td style="width:236px;">EMP-13J</td>
			<td>Round screw hollow punch</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Professional Platic</td>
			<td style="width:236px;">Chemfluor MFA Tube</td>
			<td>Minitube for isolating thermocouple wires</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Radiospar</td>
			<td style="width:236px;">RS 370-6717</td>
			<td>S-type flat pin thermocouple connector</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">LEMER</td>
			<td style="width:236px;"></td>
			<td>Lead (bulk)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Goodfellow</td>
			<td style="width:236px;">FP301305</td>
			<td>Polyt&#233;trafluoro&#233;thyl&#232;ne - Film ; 0.15 mm thickness</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Heraeus</td>
			<td style="width:236px;">81128696</td>
			<td>Pure Platinum wire</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Heraeus</td>
			<td style="width:236px;">81128743</td>
			<td>Platinum90%/Rhodium10% wire</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Alfa Aesar</td>
			<td style="width:236px;">M11C056</td>
			<td>Nickel foil 0.025 thickness annealed 99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">DP/precision</td>
			<td style="width:236px;"></td>
			<td>Tools to produce the salt pieces and lead piece (custom-made)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:237px;">Polyco Bodyguards</td>
			<td style="width:236px;">GL890</td>
			<td>Blue Nitrile Medical Examination gloves</td>
		</tr>
	</tbody>
</table>

high-pressure, high-temperature deformation experiment using the new generation griggs-type apparatus

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature (&#62; 300 &#176;C). However, because of the low stress resolution of current solid-pressure-medium apparatuses, high-resolution measurements are today restricted to low-pressure deformation experiments in the gas-pressure-medium apparatus. A new generation of solid-medium piston-cylinder (&#34;Griggs-type&#34;) apparatus is here described. Able to perform high-pressure deformation experiments up to 5 GPa and designed to adapt an internal load cell, such a new apparatus offers the potential to establish a technological basis for high-pressure rheology. This paper provides video-based detailed documentation of the procedure (using the &#34;conventional&#34; solid-salt assembly) to perform high-pressure, high-temperature experiments with the newly designed Griggs-type apparatus. A representative result of a Carrara marble sample deformed at 700 &#176;C, 1.5 GPa and 10-5 s-1 with the new press is also given. The related stress-time curve illustrates all steps of a Griggs-type experiment, from increasing pressure and temperature to sample quenching when deformation is stopped. Together with future developments, the critical steps and limitations of the Griggs apparatus are then discussed.

Figure 9 shows an example of a stress-time curve resulting from the new generation Griggs-type apparatus during pure shear (co-axial) deformation of Carrara marble (8-mm-long core sample) at a strain rate of 10-5 s-1, a temperature of 700 &#176;C and a confining pressure of 1.5 GPa. During such an experiment, both the pressure and temperature are first increased alternatingly, mainly to prevent the NaCl from melting. The molten NaCl is very corrosive for the sample and it may irreversibly damage the thermocouple. All along the successive steps of increasing pressure and temperature - here referred as the &#34;pumping stage&#34; (Figure 9) &#8211; the lead piece has the function of preventing the sample from becoming deformed by transferring stresses from &#963;1 to &#963;3 and conversely, maintaining a more or less isostatic stress state in the sample assembly.
When the target pressure and temperature are achieved, a period of &#34;hot-pressing&#34; may be applied. Although optional, this step &#8211; of commonly 24 h duration &#8211; may be required to sinter the sample powder before deformation, if applicable. The &#963;1 piston/actuator is then advanced to deform the sample, giving rise to the so-called &#34;deformation stage&#34;. This latter is first characterized by a steep-to-gentle increase of differential stress (&#963;1 - &#963;3), which is due to friction induced by 1) the packing rings and 2) the increasing surface of contact between the &#963;1 piston and lead piece while &#963;1 is moving through the lead. This &#34;run-in&#34; section should have a sufficient duration in order to determine the hit point (contact between the &#963;1 piston and top alumina piston) accurately by curve fitting (Figure 9). For this purpose, a significant thickness of lead (&#8805; 2 mm) between the &#963;1 piston and alumina piston is required before starting advancing &#963;1. When approaching the top alumina piston, lead is extruded faster as a thin sample thickness, causing strain hardening in the lead and promoting a progressive stress increase until the &#963;1 piston is pushing on the sample column. The stress curve then increases steeply up to yield stress conditions, which theoretically defines the transition from elastic to plastic behaviors (Figure 9). As required to define the differential stress, the hit point of the experiment is subsequently deduced from the intersection between the extensions of the &#34;elastic&#34; curve and &#34;run-in&#34; curve (Figure 9).
When deformation is finally stopped, the temperature is decreased very quickly (&#8776; 300 &#176;C/min) to preserve microstructures. A substantial drop of pressure necessarily occurs during the &#34;sample quenching&#34;, but following this drop, both the &#963;1 and &#963;3 pistons are moved back slowly by reducing the oil pressure in the hydraulic rams (&#8776; 5 MPa/min). This is required to limit the formation of unloading cracks, although some cracking is inevitable. After experiment, the stress-time curve is subsequently corrected to produce a stress-strain curve of the deformed sample up from the hit point (see inset in Figure 9). These corrections include 1) the stiffness/extension of the apparatus and 2) the friction induced by the packing rings and lead piece15,19. Figure 10 also shows two examples of the post-experiment sample assembly, one containing the core sample of Carrara marble (Figure 10A and 10B) and a second one of an olivine powder sintered, and then deformed in general shear at 900 &#176;C and 1.2 GPa using the former Griggs-type apparatus23 (Figure 10C and 10D).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56841/56841fig1.jpg" /> 
Figure 1: The new generation Griggs-type apparatus. Schematic drawings of the Griggs-type apparatus now available at the Institut des Sciences de la Terre d&#39;Orl&#233;ans (ISTO, France) and &#201;cole Normale Sup&#233;rieure de Paris (ENS Paris, France). While the sample assembly lies within the pressure vessel, high confining pressure and differential stress are applied by independent syringe pumps through hydraulic rams and pistons/actuators. The temperature is increased using a low-voltage/high-amperage electrical current injected from below the assembly (see side view) through a resistive graphite furnace. To preserve the tungsten carbide (WC) die, the pressure vessel is also cooled by water flow from bottom to top through the cooling plates/boxes and the vessel itself. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56841/56841fig2.jpg" /> 
Figure 2: Sample assembly. Detailed view of the pieces that compose the sample assembly. The &#963;1 piston, &#963;3 piston and base plate are also shown &#8211; part of them in transparency &#8211; to locate the position of each piece with respect to the Griggs-type apparatus. A) Sample assembly of a coaxial experiment. B) Exploded view of the sample assembly, either for a &#34;coaxial&#34; (white) or &#34;general shear&#34; sample (green). The lead piece and lower salt piece are shown in transparency. C) 3D view of a mullite 2-hole sheathing S-type thermocouple used to monitor the temperature during an experiment. WC = tungsten carbide. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56841/56841fig3.jpg" /> 
Figure 3: Tools required to cold press the outer and inner salt pieces from NaCl powder. A) 3D views during pressing (14 tons for 30 s) and extraction of the outer salt pieces (left), and scaled drawings of the related tool components (right). B) 3D views during pressing (6 tons for 30 s) and extraction of the inner salt piece (left), and scaled drawings of the related tool components (right). Some parts are shown in transparency. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56841/56841fig4v2.jpg" /> 
Figure 4: Tool required to drill the lower outer salt piece. A) 3D views before (top) and during (bottom) drilling. B) Scaled drawings (3D, top and side views) of the tool (only one part is shown). <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56841/56841fig5.jpg" /> 
Figure 5: Tools required to produce the platinum jacket. A) 3D view (left) and scaled drawings (right) of the tool needed to produce the platinum cups. By pushing on the 10-mm-diameter platinum disc, its outer part is bent up over 1 mm thickness into a cup-shape, so that it can fit into and be welded together with the 8-mm-diameter platinum jacket. B) 3D view (top) and scaled drawings (bottom) of the tool needed to weld a platinum cup to the platinum jacket (only half of the top piece is shown). <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56841/56841fig6.jpg" /> 
Figure 6: Tool required to produce the lead piece. A) 3D view during pressing (4 tons for 30 s) of the molten lead (50 g). The component #2 is shown in transparency. B) 3D view during extraction of the lead piece (the dimensions are shown in the top left inset). C) Scaled drawings of the tool components. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56841/56841fig7v2.jpg" /> 
Figure 7: Clamps to fix the basal piston to the pressure vessel. 3D view of the pressure vessel, basal piston and clamps (top), and scaled drawings of the top and bottom parts of one clamp, including a 3D view (bottom). <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56841/56841fig8.jpg" /> 
Figure 8: Hydraulics of the pumps and cooling systems. Scheme of the hydraulics &#8211; including valves (V), electro-valves (EV) and oil tank (T) &#8211; of the deformation pump (purple), confining pump (orange), cooling system of the pressure vessel (light blue) and cooling system of the confining/end-load ram (yellow). <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig8large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56841/56841fig9.jpg" /> 
Figure 9: Representative result. Example of a stress-time curve of a deformation experiment using the new generation Griggs-type apparatus. This experiment has been performed coaxially on a core sample (8 mm long) of Carrara marble at 700 &#176;C, 1.5 GPa and a strain rate of 10-5 s-1. This result illustrates the successive steps of a Griggs-type experiment, which includes 1) a &#34;pumping stage&#34; to increase pressure and temperature, 2) a &#34;hot-pressing stage&#34; to sinter the sample, if applicable, 3) a &#34;deformation stage&#34; to deform the sample, and 4) a &#34;quenching stage&#34; to decrease pressure and temperature. During deformation, the &#963;1 piston first advances through the lead (&#34;run-in&#34; step), and then pushes on the alumina piston to properly deform the sample (up from the hit point), giving rise to elastic-then-plastic behavior (see text). After correction of the stress-time curve from friction and stiffness/extension of the apparatus, a stress-strain curve is produced up from the hit point (inset). &#963;1 = stress applied by the &#963;1 piston; &#963;3 = stress applied by the &#963;3 piston; P = confining (isostatic) pressure; T = temperature. &#963;1-&#963;3 = differential stress. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig9large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/56841/56841fig10.jpg" /> 
Figure 10: Sample extraction. A) Lower part of the sample assembly extracted after the experiment described in Figure 9. B) Sample of Carrara marble (still wrapped into its platinum jacket) after pure shear deformation at 700 &#176;C and 1.5 GPa in the new Griggs-type apparatus. C) Lower part of a sample assembly containing a sample of olivine powder sintered, and then deformed in general shear at 900 &#176;C and 1.2 GPa with the former Griggs-type apparatus23. D) Olivine sample and alumina shear pistons (still wrapped into the platinum jacket) after extraction from the sample assembly. TC = Thermocouple. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56841/56841fig10large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus at JoVE.com

High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus

Rock deformation needs to be quantified at high pressure. A description of the procedure to perform deformation experiments in a newly designed solid-medium Griggs-type apparatus is here given. This provides technological basis for future rheological studies at pressures up to 5 GPa.

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature ...

high-pressure-high-temperature-deformation-experiment-using-new

Nanyang Technological University

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Unit 1

Deflection of Beams

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18.7K Views.  Université d’Orléans. Rock deformation needs to be quantified at high pressure. A description of the procedure to perform deformation experiments in a newly designed solid-medium Griggs-type apparatus is here given. This provides technological basis for future rheological studies at pressures up to 5 GPa.

Video: High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail millet. Recently, the 510 Mb genome of foxtail millet, S. italica, has been sequenced 1,2 and a 25x coverage genome sequence of the weedy relative S. viridis is in progress. S. viridis has a number of characteristics that make it a potentially excellent model genetic system including a rapid generation time, small stature, simple growth requirements, prolific seed production 3 and developed systems for both transient and stable transformation 4. However, the genetics of S. viridis is largely unexplored, in part, due to the lack of detailed methods for performing crosses. To date, no standard protocol has been adopted that will permit rapid production of seeds from controlled crosses.
The protocol presented here is optimized for performing genetic crosses in S. viridis, accession A10.1. We have employed a simple heat treatment with warm water for emasculation after pruning the panicle to retain 20-30 florets and labeling of flowers to eliminate seeds resulting from newly developed flowers after emasculation. After testing a series of heat treatments at permissive temperatures and varying the duration of dipping, we have established an optimum temperature and time range of 48 &deg;C for 3-6 min. By using this method, a minimum of 15 crosses can be performed by a single worker per day and an average of 3-5 outcross progeny per panicle can be recovered. Therefore, an average of 45-75 outcross progeny can be produced by one person in a single day. Broad implementation of this technique will facilitate the development of recombinant inbred line populations of S. viridis X S. viridis or S. viridis X S. italica, mapping mutations through bulk segregant analysis and creating higher order mutants for genetic analysis.

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

We have developed a methodology for performing crosses in Setaria viridis (S. viridis). The method involves pruning the panicle prior to a hot water treatment to kill viable pollen. Crosses are performed following a well-controlled growth regime and typically result in the recovery of 1 to 7 cross-pollinated seed/s per panicle.

Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail ...

A New Application of the Electrical Penetration Graph (EPG) for Acquiring and Measuring Electrical Signals in Phloem Sieve Elements

Electrophysiological properties of cells are often studied in vitro, after dissociating them from their native environments. However, the study of electrical transmission between distant cells in an organism requires in vivo, artifact-free recordings of cells embedded within their native environment. The transmission of electrical signals from wounded to unwounded areas in a plant has since long piqued the interest of botanists. The phloem, the living part of the plant vasculature that is spread throughout the plant, has been postulated as a major tissue in electrical transmission in plants. The lack of suitable electrophysiological methods poses many challenges for the study of the electrical properties of the phloem cells in vivo. Here we present a novel approach for intracellular electrophysiology of sieve elements (SEs) that uses living aphids, or other phloem-feeding hemipteran insects, integrated in the electrical penetration graph (EPG) circuit. The versatility, robustness, and accuracy of this method made it possible to record and study in detail the wound-induced electrical signals in SEs of central veins of the model plant Arabidopsis thaliana1. Here we show that EPG-electrodes can be easily implemented for intracellular electrophysiological recordings of SEs in marginal veins, as well as to study the capacity of SEs to respond with electrical signals to several external stimuli. The EPG approach applied to intracellular electrophysiology of SEs can be implemented to a wide variety of plant species, in a large number of plant/insect combinations, and for many research aims.

A New Application of the Electrical Penetration Graph EPG for Acquiring and Measuring Electrical Signals in Phloem Sieve Elements

Electrical Penetration Graph (EPG) is a well-established technique for studying the feeding behavior of stylet-bearing insects. Here we show a new application of EPG as a non-invasive tool for the acquisition of intracellular electrophysiology recordings of sieve elements (SEs), the cells that form the phloem vasculature in plants.

Electrophysiological properties of cells are often studied in vitro, after dissociating them from their native environments. However, the study of ...

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. Yet the in situ study of DOM is difficult as the molecular complexity of the DOM pool cannot be easily reproduced for experimental purposes. Nutrient additions to streams however, have been shown to repeatedly alter the in situ and ambient DOM pool. Here we demonstrate an easily replicable field-based method for manipulating the ambient pool of DOM at the ecosystem scale. During nutrient pulse experiments changes in the concentration of both dissolved organic carbon and dissolved organic nitrogen can be examined across a wide-range of nutrient concentrations. This method allows researchers to examine the controls on the DOM pool and make inferences regarding the role and function that certain fractions of the DOM pool play within ecosystems. We advocate the use of this method as a technique to help develop a deeper understanding of DOM biogeochemistry and how it interacts with nutrients. With further development this method may help elucidate the dynamics of DOM in other ecosystems.

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Dissolved organic matter provides an important source of energy and nutrients to stream ecosystems. Here we demonstrate a field-based method to manipulate the ambient pool of dissolved organic matter in situ through easily replicable nutrient pulses.

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. ...

Determination of Inorganic Arsenic in a Wide Range of Food Matrices using Hydride Generation - Atomic Absorption Spectrometry.

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to inorganic arsenic through diet, information about distribution of arsenic species in various food types must be generated. A method, previously validated in a collaborative trial, has been applied to determine inorganic arsenic in a wide variety of food matrices, covering grains, mushrooms and food of marine origin (31 samples in total). The method is based on detection by flow injection-hydride generation-atomic absorption spectrometry of the iAs selectively extracted into chloroform after digestion of the proteins with concentrated HCl. The method is characterized by a limit of quantification of 10 &#181;g/kg dry weight, which allowed quantification of inorganic arsenic in a large amount of food matrices. Information is provided about performance scores given to results obtained with this method and which were reported by different laboratories in several proficiency tests. The percentage of satisfactory results obtained with the discussed method is higher than that of the results obtained with other analytical approaches.

The usefulness of an analytical method to determine inorganic arsenic in a wide range of food matrices is demonstrated. The method consists of selective extraction of inorganic arsenic into chloroform with a final determination by hydride generation-atomic absorption spectrometry.

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to ...

Development of New Methods for Quantifying Fish Density Using Underwater Stereo-video Tools

The use of video camera systems in ecological studies of fish continues to gain traction as a viable, non-extractive method of measuring fish lengths and estimating fish abundance. We developed and implemented a rotating stereo-video camera tool that covers a full 360 degrees of sampling, which maximizes sampling effort compared to stationary camera tools. A variety of studies have detailed the ability of static, stereo-camera systems to obtain highly accurate and precise measurements of fish; the focus here was on the development of methodological approaches to quantify fish density using rotating camera systems. The first approach was to develop a modification of the metric MaxN, which typically is a conservative count of the minimum number of fish observed on a given camera survey. We redefine MaxN to be the maximum number of fish observed in any given rotation of the camera system. When precautions are taken to avoid double counting, this method for MaxN may more accurately reflect true abundance than that obtained from a fixed camera. Secondly, because stereo-video allows fish to be mapped in three-dimensional space, precise estimates of the distance-from-camera can be obtained for each fish. By using the 95% percentile of the observed distance from camera to establish species-specific areas surveyed, we account for differences in detectability among species while avoiding diluting density estimates by using the maximum distance a species was observed. Accounting for this range of detectability is critical to accurately estimate fish abundances. This methodology will facilitate the integration of rotating stereo-video tools in both applied science and management contexts.

We describe a new method for counting fishes, and estimating relative abundance (MaxN) and fish density using rotating stereo-video camera systems. We also demonstrate how to use distance from camera (Z distance) to estimate species-specific detectability.

The use of video camera systems in ecological studies of fish continues to gain traction as a viable, non-extractive method of measuring fish lengths and ...

An Ultra-clean Multilayer Apparatus for Collecting Size Fractionated Marine Plankton and Suspended Particles

The distributions of many trace elements in the ocean are strongly associated with the growth, death, and re-mineralization of marine plankton and those of suspended/sinking particles. Here, we present an all plastic (Polypropylene and Polycarbonate), multi-layer filtration system for collection of suspended particulate matter (SPM) at sea. This ultra-clean sampling device has been designed and developed specifically for trace element studies. Meticulous selection of all non-metallic materials and utilization of an in-line flow-through procedure minimizes any possible metal contamination during sampling. This system has been successfully tested and tweaked for determining trace metals (e.g., Fe, Al, Mn, Cd, Cu, Ni) on particles of varying size in coastal and open ocean waters. Results from the South China Sea at the South East Asia Time-Series (SEATS) station indicate that diurnal variations and spatial distribution of plankton in the euphotic zone can be easily resolved and recognized. Chemical analysis of size-fractionated particles in surface waters of the Taiwan Strait suggests that the larger particles (&#62;153 &#181;m) were mostly biologically derived, while the smaller particles (10 - 63 &#181;m) were mostly composed of inorganic matter. Apart from Cd, the concentrations of metals (Fe, Al, Mn, Cu, Ni) decreased with increasing size.

Plankton and suspended particles play a major role in the biogeochemical cycles in the ocean. Here, we provide an ultra-clean, low stress method for the collection of various sizes of particles and plankton at sea with the capability of handling large volumes of seawater.

The distributions of many trace elements in the ocean are strongly associated with the growth, death, and re-mineralization of marine plankton and those ...

A Novel Method for the Pentosan Analysis Present in Jute Biomass and Its Conversion into Sugar Monomers Using Acidic Ionic Liquid

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, lower vapor pressure, non-flammability, higher heat capacity, and tunable solubility and acidity. Here, we demonstrate a method for the synthesis of C5 sugars (xylose and arabinose) from the pentosan present in jute biomass in a one-pot process by utilizing a catalytic amount of Br&#248;nsted acidic 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate IL. The acidic IL is synthesized in the lab and characterized using NMR spectroscopic techniques for understanding its purity. The various properties of BAIL are measured such as acid strength, thermal and hydrothermal stability, which showed that the catalyst is stable at a higher temperature (250 &#176;C) and possesses very high acid strength (Ho 1.57). The acidic IL converts over 90% of pentosan into sugars and furfural. Hence, the presenting method in this study can also be employed for the evaluation of pentosan concentration in other kinds of lignocellulosic biomass.

We present a protocol for the synthesis of C5 sugars (xylose and arabinose) from a renewable non-edible lignocellulosic biomass (i.e., jute) with the presence of Br&#248;nsted acidic ionic liquids (BAILs) as the catalyst in water. The BAILs catalyst exhibited better catalytic performance than conventional mineral acid catalysts (H2SO4 and HCl).

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, ...

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

A flow-through device for using the biodeposition method to quantify filtration and feeding behavior of bivalve mollusks was modified for shipboard use. A two-dimensional gimbal table built around the device isolates the apparatus from boat motion, thereby allowing the accurate quantification of bivalve filtration variables at offshore shellfish aquaculture sites.

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves ...

An Optimized Rhizobox Protocol to Visualize Root Growth and Responsiveness to Localized Nutrients

Roots are notoriously difficult to study. Soil is both a visual and mechanical barrier, making it difficult to track roots in situ without destructive harvest or expensive equipment. We present a customizable and affordable rhizobox method that allows the non-destructive visualization of root growth over time and is particularly well-suited to studying root plasticity in response to localized resource patches. The method was validated by assessing maize genotypic variation in plasticity responses to patches containing 15N-labeled legume residue. Methods are described to obtain representative developmental measurements over time, measure root length density in resource-containing and control patches, calculate root growth rates, and determine 15N recovery by plant roots and shoots. Advantages, caveats, and potential future applications of the method are also discussed. Although care must be taken to ensure that experimental conditions do not bias root growth data, the rhizobox protocol presented here yields reliable results if carried out with sufficient attention to detail.

Visualizing and measuring root growth in situ is extremely challenging. We present a customizable rhizobox method to track root development and proliferation over time in response to nutrient enrichment. This method is used to analyze maize genotypic differences in root plasticity in response to an organic nitrogen source.

Roots are notoriously difficult to study. Soil is both a visual and mechanical barrier, making it difficult to track roots in situ without destructive ...

A New Portable In Vitro Exposure Cassette for Aerosol Sampling

This protocol introduces a new in vitro exposure system, capable of being worn, including its characterization and performance. Air-liquid interface (ALI) in vitro exposure systems are often large and bulky, making transport to the field and operation at the source of emission or within the breathing zone difficult. Through miniaturization of these systems, the lab can be brought to the field, expediting processing time and providing a more appropriate exposure method that does not alter the aerosol prior to contacting the cells. The Portable In vitro Exposure Cassette (PIVEC) adapts a 37 mm filter cassette to allow for in vitro toxicity testing outside of a traditional laboratory setting. The PIVEC was characterized using three sizes of copper nanoparticles to determine deposition efficiency based on gravimetric and particle number concentration analysis. Initial cytotoxicity experiments were performed with exposed lung cells to determine the ability of the system to deposit particles while maintaining cell viability. The PIVEC provides a similar or increased deposition efficiency when comparing to available perpendicular flow in vitro exposure devices. Despite the lower sample throughput, the small size gives some advantages to the current in vitro ALI exposure systems. These include the ability to be worn for personal monitoring, mobility from the laboratory to the source of emission, and the option to set-up multiple systems for spatial resolution while maintaining a lower user cost. The PIVEC is a system capable of collecting aerosols in the field and within the breathing zone onto an air-interfaced, in vitro model.

A New Portable In Vitro Exposure Cassette for Aerosol Sampling

Here, we present a protocol to perform portable cellular aerosol exposures and measure cellular response. The method uses cells, grown at the air-liquid interface, mimicking in vivo physiology. Cellular response to copper nanoparticle aerosols was observed as oxidative stress through reactive oxygen species generation and cytotoxicity as lactate dehydrogenase release.

This protocol introduces a new in vitro exposure system, capable of being worn, including its characterization and performance. Air-liquid interface (ALI) ...