Name: minimum burning pressures of water-based emulsion explosives
Uploaded: 2017-10-31T13:00:00
Description: Watch this Scientific Journal Video about Minimum Burning Pressures of Water-based Emulsion Explosives at JoVE.com

The development of the testing protocol reported in this publication results from a joint research project between Natural Resources Canada (CanmetCERL, Explosives R&#38;D Section) and Orica Mining Services. Permission of Orica Mining Services to publish non-proprietary information on this subject is fully acknowledged. The participation of CanmetCERL&#39;s Analytical Section to the physical characterization of the various AWEs prepared throughout the present work is also gratefully acknowledged.

NOTE: The materials and equipment used here are listed in the Table of Materials.
1. Preparation of Ignition Wire Assemblies
NOTE: Wearing nitrile gloves is recommended for this operation.
<ol>
	<li>Measure a pre-determined length of nichrome (NiCr) wire and cut using a wire cutter. Cut 85 mm lengths for 76.2 mm (3&#34;) long test cells.</li>
	<li>Using needle nose pliers, bend the NiCr wire to make a small loop at each end. With a proper crimping tool, splice eac...

<ol>
	<li>Bluhm, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonium+nitrate+emulsion+blasting+agent+and+method+of+preparing+same.">Ammonium nitrate emulsion blasting agent and method of preparing same.</a> US Patent. , (1969).</li><li>Persson, P. -. A., Holmberg, R., Lee, 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> Rock Blasting and Explosives Engineering. , 86 (1993).</li><li>Perlid, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pump+Safety+Tests+Regarding+Emulsion+Explosives.">Pump Safety Tests Regarding Emulsion Explosives.</a> Proceedings of the 22nd Annual Conference on Explosives and Blasting Techniques, International Society of Explosives Engineers. 2, 101-107 (1996).</li><li>Chan, S. K., Kirchnerova, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ignition+and+Combustion+Characteristics+of+Water-gel+Explosives.">Ignition and Combustion Characteristics of Water-gel Explosives.</a> Proceedings of the 18th Explosives Safety Seminar, U.S. DOD. , 193-200 (1978).</li><li>Guidelines for the Pumping of Water-Based Explosives. Natural Resources Canada, Explosives Regulatory Division, Minister of Public Works and Government Services Canada, Catalog no. M37-53/2003E Available from: <a target="_blank" href="https://miningandblasting.files.wordpress.com/2009/09/canadian-guidelines-for-pumping-of-water-based-explosives.pdf">https://miningandblasting.files.wordpress.com/2009/09/canadian-guidelines-for-pumping-of-water-based-explosives.pdf</a> (2016)</li><li>. Guidelines for the Pumping of Bulk, Water-Based Explosives Available from: <a target="_blank" href="https://miningandblasting.files.wordpress.com/2009/09/pumping-of-water-based-explosives-june-2010.pdf">https://miningandblasting.files.wordpress.com/2009/09/pumping-of-water-based-explosives-june-2010.pdf</a> (2010)</li><li>Wang, 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> Ignition and Combustion Characteristics of Emulsion Explosives under Pressure. , (1991).</li><li>Hirosaki, Y., Suzuki, S., Takahashi, Y., Kato, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burning+Characteristics+of+Emulsion+Explosives+(I)+–+Pressurized+Vessel+Test.">Burning Characteristics of Emulsion Explosives (I) – Pressurized Vessel Test.</a> Kayaku Gakkaishi. 61, 35-41 (2000).</li><li>Turcotte, R., Lightfoot, P. D., Badeen, C. M., Vachon, M., Jones, D. E. 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+Pressurized+Vessel+Test+to+Measure+the+Minimum+Burning+Pressure+of+Water-Based+Explosives.">A Pressurized Vessel Test to Measure the Minimum Burning Pressure of Water-Based Explosives.</a> Propellants, Explos., Pyrotech. 30, 118-126 (2005).</li><li>Turcotte, R., Goldthorp, S., Badeen, C., Chan, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hot-wire+Ignition+of+AN-based+Emulsions.">Hot-wire Ignition of AN-based Emulsions.</a> Propellants, Explos., Pyrotech. 33, 472-481 (2008).</li><li>Chan, S. K., Turcotte, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Onset+Temperatures+in+Hot-wire+Ignition+of+AN-Based+Emulsions.">Onset Temperatures in Hot-wire Ignition of AN-Based Emulsions.</a> Propellants, Explos., Pyrotech. 34, 41-49 (2009).</li><li>Goldthorp, S., Turcotte, R., Badeen, C. M., Chan, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimum+Pressure+for+Sustained+Combustion+in+AN-based+Emulsions.">Minimum Pressure for Sustained Combustion in AN-based Emulsions.</a> Proceedings of the 35th International Pyrotechnics Seminar. , 385-394 (2008).</li><li>Turcotte, R., Goldthorp, S., Badeen, C. M., Feng, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Physical+Characteristics+and+Ingredients+on+the+Minimum+Burning+Pressure+of+Ammonium+Nitrate+Emulsions.">Influence of Physical Characteristics and Ingredients on the Minimum Burning Pressure of Ammonium Nitrate Emulsions.</a> Propellants, Explos., Pyrotech. 35, 233-239 (2010).</li><li>Badeen, C. M., Goldthorp, S., Turcotte, R., Feng, H., Chan, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Formulation+Changes+on+the+Minimum+Burning+Pressure+of+Ammonium+Nitrate+Emulsions.">Effect of Formulation Changes on the Minimum Burning Pressure of Ammonium Nitrate Emulsions.</a> Proceedings of the "10i&#232;me Congr&#232;s International de Pyrotechnie", in conjunction with the 37th International Pyrotechnics Seminar (Europyro 2011) , Session S1a. , (2011).</li><li>Turcotte, R., Goldthorp, S., Badeen, C. M., Johnson, C., Feng, H., Chan, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Physical+Characteristics+and+Ingredients+on+the+Minimum+Burning+Pressure+of+Ammonium+Nitrate+Emulsions.">Influence of Physical Characteristics and Ingredients on the Minimum Burning Pressure of Ammonium Nitrate Emulsions.</a> , 197-206 (2009).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria. , 200-207 (2015).</li><li>The Minimum Burning Test for Ammonium Nitrate Emulsions. SAFEX Newsletter Available from: <a target="_blank" href="https://www.safex-international.org/safex/page-newsletter.html">https://www.safex-international.org/safex/page-newsletter.html</a> (2016)</li></ol>

Our work demonstrated that the linear hot-wire geometry with 0.5 mm diameter NiCr straight wire and 10 to 16 A ignition current was adequate to ignite AWEs with water contents up to 25 mass %. For high viscosity formulations (such as packaged emulsion products), horizontal and vertical configurations provide almost identical results 17. However, for low viscosity formulae (such as bulk emulsion products) gravity effects in vertical configuration induce emulsion flow which disturbs the ignition pro...

The ammonium nitrate water-based emulsion (AWE) explosive was invented in 1961. It consists of microscopic droplets of a liquid oxidizer solution surrounded by a continuous oil phase. The first stable and practically useful emulsion blasting explosive was developed by Harold F. Bluhm in the USA (1969) 1,2. However, the successful commercialization of this type of explosive did not really happen before the beginning of the 1980s.
With the large scale of modern mining operations and the advent of fast bulk explosive loading methodology, very large volumes of AWE explosives have to be manufactured and transported. One tanker load typically transports 20 tons of AWE and many such truck loads are usually necessary to load only one blast. Accidental initiation of such large quantities of explosives would be particularly disastrous and, therefore, a good knowledge of their hazardous properties is required to design corresponding safe handling systems. While it is well known that emulsions are relatively insensitive to mechanical events (i.e. impact and friction events), accidental explosions have still been reported 3 while handling this type of explosive, particularly in pumping applications.
It has been known since the 1970&#39;s 4 that a minimum ambient pressure is required for self-sustained combustion to take place into water-based explosives. This latter value has usually been termed the &#34;Minimum Burning Pressure&#34; (MBP). From a safety point of view, knowledge of this threshold could allow manufacturers to better estimate safe operating pressures for various handling equipment.
The Department of Natural Resources of the Government of Canada has published &#34;Guidelines for the Pumping of Water-Based explosives&#34; 5, which state that using pumping pressures well below the MBP of the emulsions or watergels is a good safety practice. It should be noticed that these guidelines were designed with the collaboration of most commercial manufacturers and that, in the USA, the Institute of Makers of Explosives (IME) has also published very similar guidelines 6. However, in these documents, there was no description or prescription on how the MBP should be measured.
In the last decades, only a few studies related to MBP measurements have been reported. Chan et al. 4 reported the results of MBP measurements for watergel explosives, which are also ammonium nitrate and water-based. They have concluded that the MBP can have a strong dependency on several formulation factors such as water content, presence of chemical sensitizers or metallic powders. In another study, Wang 7 described a 2.5 L pressure vessel pressurized with N2 and used a Bruceton up-and-down method to determine the MBP for basic AWEs. With this system, MBP values of the order of 15 MPa were measured for a basic emulsion having a water content of 16 mass %.
Using a similar pressurized vessel test, Hirosaki et al. 8 have reported the results of some MBP measurements for AWE explosives. They have noted that the nature (i.e. glass or resin) of the micro-spheres being used to sensitize the explosives also has a strong influence on the results. More recently, Turcotte et al. 9 have developed a system similar to that of Wang and Hirosaki et al. and have attempted to use it to measure the MBP of some AWEs. However, they have found many possible problems that may lead to erroneous MBP determinations. In particular, it was noted that the ignition source geometry (nichrome wire coil) had never been properly validated for AWEs. In 2008, Turcotte et al. 10 and Chan et al. 11, have developed both an apparatus based on a calibrated ignition wire system and an associated methodology to measure the MBP of AWEs. They have also used the facility to study the ignition characteristics of typical AWEs, measured the energy requirements to obtain reliable ignitions 12 and studied the influence of physical characteristics and ingredients on the MBP of a wide variety of AWE explosives 13,14. This MBP measurement technique is presently being proposed as a standard test within the United Nation Transport of Dangerous Goods (UN TDG) Tests and Criteria for the classification for transport of AWEs 15.

<table>
	<tbody>
		<tr>
			<td>Nitrile gloves (100/pk)</td>
			<td>Fisher Scientific</td>
			<td>19149863B</td>
			<td>https://www.fishersci.ca/shop/products/purple-nitrile-exam-gloves-6/19149863b?searchHijack=true&#38;searchTerm=19149863B&#38;searchType=RAPID&#38;matchedCatNo=19149863B</td>
		</tr>
		<tr>
			<td>NiCr60 wire 24 AWG (200 feet per roll)</td>
			<td>Omega Engineering</td>
			<td>NIC60-020-200</td>
			<td>http://www.omega.ca/pptst_eng/NI60.html</td>
		</tr>
		<tr>
			<td>Wire cutters: Mini Diagonal Cutting Pliers, 5 in.</td>
			<td>Canadian Tire</td>
			<td>Product #058-4736-0</td>
			<td>http://www.canadiantire.ca/en/pdp/mastercraft-mini-diagonal-cutting-pliers-0584736p.html#srp</td>
		</tr>
		<tr>
			<td>Mini needle nose pliers, 5 in.</td>
			<td>Canadian Tire</td>
			<td>Product #058-4731-0</td>
			<td>http://www.canadiantire.ca/en/pdp/mastercraft-mini-needle-nose-pliers-0584731p.html#srp</td>
		</tr>
		<tr>
			<td>Crimping tool, 8.5 in.</td>
			<td>Canadian Tire</td>
			<td>Product #058-4617-4</td>
			<td>http://www.canadiantire.ca/en/pdp/mastercraft-8-in-crimping-tool-0584617p.html#srp</td>
		</tr>
		<tr>
			<td>Bare copper wire (14AWG)</td>
			<td>Electronics Plus</td>
			<td>2000BC-14-5/5 lb roll</td>
			<td>Bare (uninsulated) copper wire</td>
		</tr>
		<tr>
			<td>Non-insulated butt-splice connectors (100 units)</td>
			<td>Electrosonic</td>
			<td>Panduit BS14-C</td>
			<td>http://www.alliedelec.com/panduit-bs14-c/70044299/?mkwid=si03ezhXY&#38;pcrid=64596948257&#38;pkw=panduit%20bs14-c&#38;pmt=b&#38;pdv=c&#38;gclid=CM_1jO-DsdMCFZKIswodMugASw</td>
		</tr>
		<tr>
			<td>Stainless Steel pipe nipples (10 - 20 units)</td>
			<td>Wolseley Inc.</td>
			<td>SSNKX3</td>
			<td>sample cells: 76.2 mm long x 12.7 mm od (3&#34; long x 0.5&#34; od) with 3 mm slit machined along the length of the cell, painted inside and out with two coats of non-conductive paint (e.g., high-heat barbeque Armor Coat or Krylon brands).</td>
		</tr>
		<tr>
			<td>High-temperature non-conductive paint</td>
			<td>Canadian Tire</td>
			<td>Product #048-0648-8</td>
			<td>http://www.canadiantire.ca/en/pdp/armor-coat-bbq-paint-0480648p.html#srp</td>
		</tr>
		<tr>
			<td>Solid green neoprene stoppers (size 0; 1 package of 68)</td>
			<td>Cole-Palmer</td>
			<td>OF-62991-04</td>
			<td>https://www.coleparmer.ca/i/cole-parmer-solid-green-neoprene-stoppers-standard-size-0-68-pk/6299104?searchterm=OF-62991-04</td>
		</tr>
		<tr>
			<td>Spatula, stainless steel</td>
			<td>Fisher Scientific</td>
			<td>14-375-10</td>
			<td>https://www.fishersci.ca/shop/products/fisherbrand-spoonula-lab-spoon/1437510?searchHijack=true&#38;searchTerm=1437510&#38;searchType=RAPID&#38;matchedCatNo=1437510</td>
		</tr>
		<tr>
			<td>7.5 L Pressure Vessel</td>
			<td>Autoclave Engineers</td>
			<td>40A-9104, 9122, 40C-1365, 2376</td>
			<td>minimum internal diameter of 127 mm; equipped with 20.7 MPa (3000 psi) rupture disc assembly; Solenoid&#38; air operated valve on the outlet; http://www.autoclaveengineers.com/products/pressure_vessels/PV_Bolted_Closure/index.html</td>
		</tr>
		<tr>
			<td>Electrodes (set of 2)</td>
			<td>Electo-meters</td>
			<td>Conax EG-375-A-SS-T, 25.4 cm (10&#34;) conductor</td>
			<td>with Teflon sealing glands; https://www.conaxtechnologies.com/wp-content/uploads/2016/03/5001D-80-105-Flanges-and-Accessories.pdf</td>
		</tr>
		<tr>
			<td>Rupture disc</td>
			<td>Oseco</td>
			<td>39859-3-1</td>
			<td>http://www.oseco.com/imgUL/files/STD_0515.pdf</td>
		</tr>
		<tr>
			<td>Universal safety head (rupture disc assembly)</td>
			<td>Autoclave Engineers</td>
			<td>SS-4600-1/2F</td>
			<td>http://www.autoclave.com/products/accessories/universal_safety_heads/index.html</td>
		</tr>
		<tr>
			<td>High-pressure valve (air-operated, fail-open)</td>
			<td>Autoclave Engineers</td>
			<td>1/2&#34; SW8XXX-CM</td>
			<td>http://www.autoclave.com/aefc_pdfs/OM_P1_Manual_Air_Valve.pdf?zoom_highlightsub=air+operated+valve#search=&#34;air operated valve&#34;</td>
		</tr>
		<tr>
			<td>Pressure transducer</td>
			<td>Omega Engineering</td>
			<td>PX176-3KS5V</td>
			<td>Amplified Voltage Output Transducer for Absolute; 0-20.7 Mpa (0-3000 psi) sealed gauge, 91 cm (36&#34;) cable http://www.omega.ca/pptst_eng/PX176.html</td>
		</tr>
		<tr>
			<td>Digital multimeter</td>
			<td>Amazon.com</td>
			<td>Fluke Model 110 Plus</td>
			<td>https://www.amazon.com/Fluke-110-Plus-essential-multimeter/dp/B01JX912I2</td>
		</tr>
		<tr>
			<td>Data acquisition Interface</td>
			<td>IOTECH</td>
			<td>Model Daqlab 2000 with DBK15 acquisition board</td>
			<td>http://www.mccdaq.com/products/daqlab2000s</td>
		</tr>
		<tr>
			<td>Personal Computer with monitor and National Instruments DASYLab Software (V13, basic) installed</td>
			<td>DELL</td>
			<td>CORETMi7 vProTM</td>
			<td>Computer must meet requirements for Dasylab 13: 1GHz + x86 compatible; Windows 7 or 8, 32-bit or 64-bit; 2 GB+ RAM</td>
		</tr>
		<tr>
			<td>oscilloscope</td>
			<td></td>
			<td></td>
			<td>Any storage oscilloscope with 2 input channels (0-10 V), 12k samples per channel and acquisition frequency of 10 ms/sample.</td>
		</tr>
		<tr>
			<td>Precision Shunt Resister</td>
			<td>Canadian Shunt Industries</td>
			<td>LA-20-100</td>
			<td>(20 A, 100 mV) Enclosed in custom box http://www.cshunt.com/pdf/la.pdf</td>
		</tr>
		<tr>
			<td>Constant Current Power Supply</td>
			<td>Agilent</td>
			<td>N6700B Low-Profile MPS Mainframe, 400W; N6754A DC Power Supply with High Speed Test Extensions option</td>
			<td>http://www.keysight.com/en/pd-1125217-pn-N6754A/high-performance-autoranging-dc-power-module-60v-20a-300w?cc=CA&#38;lc=eng</td>
		</tr>
		<tr>
			<td>Inlet valve</td>
			<td>Ottawa Valves and Fittings</td>
			<td>Swagelok SS-43GS4-PT</td>
			<td>https://www.swagelok.com/en/catalog/Product/Detail?part=SS-43GS4</td>
		</tr>
		<tr>
			<td>Full face mask</td>
			<td>Cooper Safety</td>
			<td>3M 7800 series</td>
			<td>http://www.coopersafety.com/product/3m-7800-series-full-face-respirator-1124.aspx</td>
		</tr>
		<tr>
			<td>General purpose cartridges</td>
			<td>Cooper Safety</td>
			<td>3M 60923</td>
			<td>http://www.coopersafety.com/product/3m-60923-organic-vapor-acid-gas-p100-cartridge-1533.aspx?sid=101950</td>
		</tr>
	</tbody>
</table>

minimum burning pressures of water-based emulsion explosives

This manuscript describes a protocol to measure the minimum pressure required for sustained burning of water-based emulsion explosives. Pumping water-based emulsion explosives for blasting applications can be very hazardous, as demonstrated by a number of pump accidents around the globe in the last decades, including some that resulted in fatalities. In Canada, the recognition of this hazard has led to the development of pumping guidelines that were endorsed by both the explosives industry and the Explosive Regulatory Division of the Canadian government. In these guidelines, it was noted that the minimum burning pressures (MBP) measured in a laboratory would provide a good guide to characterize the behaviour of these products in pumping systems. The same guidelines also call for the design of pump systems that prevent, whenever possible, pressures from exceeding the MBP of the product being pumped. At the time of publication of these guidelines, a methodology existed for measuring such MBP values but it had never been validated to measure the MBP of ammonium nitrate water-based emulsions (AWEs). AWEs are now used much more widely than any other water-based explosives and precursors in on-site bulk loading operations.
The Canadian Explosives Research Laboratory (CanmetCERL) has been conducting research over the last ten years to develop a validated testing protocol to measure and interpret representative MBP values for AWEs. The test, as it is performed today, will be described and the critical components will be justified by reference to recent published data. Results of MBP measurements, for a range of AWE products, will be presented. Inclusion of the MBP test in the test standards for the authorization of high explosives in Canada will also be discussed.

Typical raw signals from a test resulting in a fully propagated event (i.e. &#34;go&#34;) are shown in Figure 6. The ignition current (blue curve) is seen to come on at t0 = 0 and to stay on until the NiCr wire burns at tb = 19.1 s. The computed average ignition current (i.e. average of all data points between t0 and tb is Ihw = 10.59 A. On the pressure record (red curve), the first sign...

Watch this Scientific Journal Video about Minimum Burning Pressures of Water-based Emulsion Explosives at JoVE.com

Minimum Burning Pressures of Water-based Emulsion Explosives

We present an apparatus based on hot-wire ignition in a pressurized enclosure and an associated methodology to measure the minimum pressure required to induce sustained combustion in water-based emulsion explosives. This method improves product characterization to allow one to use them more safely during pumping and mixing operations.

This manuscript describes a protocol to measure the minimum pressure required for sustained burning of water-based emulsion explosives. Pumping ...

Research

JoVE Journal

Chemistry

Determination of the Gas-phase Acidities of Oligopeptides

Amino acid residues located at different positions in folded proteins often exhibit different degrees of acidities. For example, a cysteine residue ...

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

The procedures described in this article involve the synthesis and isolation of hypervalent iodonium alkynyl triflates (HIATs) and their subsequent ...

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass ...

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of FÃƒÆ’Ã‚Â¢Ãƒâ€¹Ã¢â‚¬Â '

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound ...

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Herein is presented a general strategy to perform reactions under mild to moderate CO2 pressures with dry ice. This technique obviates the need for ...

Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides

Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides

The age of a submarine hydrothermal sulfide is a significant index for estimating the size of hydrothermal ore deposits. Uranium and thorium isotopes in ...

Enzymatic Synthesis of Epoxidized Metabolites of Docosahexaenoic, Eicosapentaenoic, and Arachidonic Acids

The epoxidized metabolites of various polyunsaturated fatty acids (PUFAs), termed epoxy fatty acids, have a wide range of roles in human physiology. These ...

Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid ...