This work was supported jointly by the Converging Research Center Program through the Ministry of Science, ICT and Future Planning, Korea (NRF-2014M3C1A8048817) and R&amp;D Convergence Program of NST (National Research Council of Science and Technology) of Republic of Korea (CAP-14-3-KRISS).

Caution: Please follow all appropriate safety practices while assembling the equipment and sample chambers. Please wear personal protective equipment (safety glasses, gloves, safety shoes, etc.).
1. Fabrication of a Sample Vacuum Chamber
<ol>
	<li>Design and fabrication of the vacuum chamber
	<ol>
		<li>Prepare and submit design drawings to a commercial vendor or an in-house machine shop for manufacturing the sample vacuum chamber. A representative example of the design drawing for a vacuum chamber made of S20C steel is shown in Figure 1. The chamber designed in this experiment is very basic and is commonly employed by vacuum companies. 
		NOTE: The manufacturer should have a basic knowledge of UHV systems.</li>
		<li>Inspect all dimensions to ensure compliance with the drawing.</li>
		<li>After shaping (machining) the vacuum chamber, cover the end CF flanges with plastic to prevent damage during transportation.</li>
	</ol>
	</li>
	<li>Cleaning 
	NOTE: Follow local environment, health, and safety regulations during chemical cleaning. Wear personal protective equipment. Handle the parts using vinyl gloves. Do not touch the parts with bare hands.
	<ol>
		<li>Clean the steel parts following the UHV cleaning procedure for steels. A typical cleaning procedure is described below.</li>
		<li>Degrease the parts using a solvent, such as acetone, at room temperature for 5 min.</li>
		<li>Clean the parts in an ultrasonic bath for 20 min using a BN cleaner (pH 13).</li>
		<li>Rinse the parts with tap water for 10 min, followed by a thorough rinse with deionized water for 20 min.</li>
		<li>Rinse thoroughly with alcohol and blow dry using dry nitrogen gas.</li>
		<li>Wrap the parts in clean, lint-free paper and allow the parts to air-dry for one day.</li>
	</ol>
	</li>
	<li>Welding 
	NOTE: Do not touch the parts with bare hands. The welder should be trained in UHV welding.
	<ol>
		<li>Place the parts on a welding bench.</li>
		<li>Preassemble the parts and align the parts as per the design drawing.</li>
		<li>Back-purge with argon gas (5 L/min) to prevent corrosion during welding.</li>
		<li>Tack weld the end flanges using the Tungsten inert gas (TIG) weld technique (argon flow rate: 8-9 L/min).15</li>
		<li>Weld the end flanges completely using the TIG technique and a turning jig. Allow the heat-affected zone to cool down to room temperature. Stop the argon gas flow.</li>
	</ol>
	</li>
	<li>Leak test
	<ol>
		<li>Seal one end of the chamber with a CF blank flange.</li>
		<li>Connect the other end to a helium leak detector (HLD).</li>
		<li>Pump down the sample vacuum chamber using the HLD.</li>
		<li>Place the heat-welded seam in a vinyl bag and fill the bag with helium gas.</li>
		<li>Measure any change in the helium level. Ensure that the chamber is leak-proof. The helium leak rate should be &#60;1 &#215; 10&#8722;11 Pa m3 sec&#8722;1 (1 &#215; 10&#8722;10 mbar L sec&#8722;1).</li>
		<li>If no leak is observed, vent the chamber. Otherwise, reweld the vacuum chamber after venting (repeat steps 1.3.3 through 1.4.5).</li>
	</ol>
	</li>
</ol>
2. Fabrication of the Oven
<ol>
	<li>Prepare and submit the design drawings to a vendor or an in-house machine shop for manufacturing the oven. Refer to the picture shown in Figure 2.</li>
	<li>Procure the required parts and equipment described in Temperature Control of List of Specific Materials/Equipment.</li>
	<li>Connect the cooling line.</li>
	<li>Supply cooling water to a chiller. Run the chiller and check for water leaks. Stop the chiller.</li>
</ol>
3. Experimental Setup for RoR Measurements
<ol>
	<li>Collect the required vacuum equipment/hardware specified in the List of Specific Materials/Equipment. The test setup primarily consists of a SRG, a residual gas analyzer (RGA), a turbomolecular pump (TMP) equipped with a roughing pump (RP), an all-metal angle valve (AVCh), a tee (CF35), and a reducer (CF35 to CF63). Additional items may include a helium leak detector and an UHV gauge, as listed in the List of Specific Materials/Equipment. The AVCh should have a rotatable flange on the seat (sealing) side to level off the SRG.</li>
	<li>Collect the wrenches (M6 and M8), copper gaskets (CF35 and CF63), and bolts/nuts (M6 and M8) required for the assembly.</li>
	<li>Use an industrial level meter to assemble the SRG.</li>
	<li>Handle the parts using vinyl gloves. Do not touch the surface that is exposed to vacuum with bare hands. Wear safety shoes.</li>
	<li>Assembly of the experimental apparatus
	<ol>
		<li>Assemble the vacuum components sequentially using copper gaskets from the pump side to the sample side, as shown in Figure 3. Always place the valve seat side facing the sample chamber. Tighten all flange joints face-to-face with a copper gasket (CF35) using a wrench (M6), except the joint between the sample chamber and the chamber isolation valve (AVCh).</li>
		<li>Adjust the SRG flange assembly and the sample chamber so that the axis of the SRG head is vertical using the level meter; within &#177;2&#176; (max) (Figure 4). Tighten the flange joint between the sample chamber and the AVCh, face-to-face, while maintaining the SRG flange&#39;s level. Refer to the SRG user&#39;s manual for detailed instructions.</li>
		<li>Connect the RP and the HLD with isolating valves (AVRo, AVHLD) to the clamp flange (KF) port of the exhaust end of the TMP. 
		Caution: Ensure that there is no mechanical shock to the SRG flange assembly or rotor.</li>
	</ol>
	</li>
	<li>Leak test
	<ol>
		<li>Turn on the HLD and wait until the detector is ready. Open the AVHLD and close the AVRo.</li>
		<li>Pump down the setup using the HLD. Refer to the HLD manual for the correct operating procedure. Wait for ~30 min to pump out the residual helium gas from the setup. Ensure that the helium level is within the minimum detectable limit of the HLD.</li>
		<li>Spray helium gas through the leak-test groove on the flanges.</li>
		<li>Measure any change in the helium level. Ensure that the chamber is leak tight. The helium leak rate should be &#60;1 &#215; 10&#8722;11 Pa m3 sec&#8722;1 (1 &#215; 10&#8722;10 mbar L sec&#8722;1).</li>
		<li>In case of leakage from the flanges, retorque the flanges.</li>
		<li>If no leaks are found, stop the leak testing and vent the vacuum system. Open the AVRo and close the AVHLD.</li>
	</ol>
	</li>
</ol>
4. Measurement of Outgassing Rates
<ol>
	<li>Pump down procedure
	<ol>
		<li>Pump down the vacuum system by switching on the TMP and the RP at the same time.</li>
		<li>While the pumping process is on, collect the necessary items for bakeout; electrical heater tapes, heater controllers, handheld multimeter, Al foil, and temperature sensors/cables.</li>
	</ol>
	</li>
	<li>Bakeout procedure
	<ol>
		<li>Remove the SRG head from the flange assembly. Wrap vacuum components (between the SRG flange assembly and the inlet flange of the TMP) in band heaters.</li>
		<li>Check and ensure that there is no electrical short circuit between the heaters and the vacuum parts using handheld multimeter.</li>
		<li>Connect the heaters to the respective controllers and wrap the chamber in Al foil.</li>
		<li>Raise the temperature to 150 &#176;C at a ramp rate of 1 &#176;C-2 &#176;C/min.</li>
		<li>Hold the chamber at 150 &#176;C for 24-48 hr using bakeout program controller. Maintain the temperature of the RGA electronics under 50 &#176;C using cooling fan.</li>
		<li>Degas each of the RGA filaments by electron bombardment for at least 5 min.</li>
		<li>Measure the RGA spectrum from 1 to 50 m/e to ensure that the H2O peak (m/e = 18) is less than one-half of the H2 peak (m/e = 2). If not, continue the bakeout.</li>
		<li>Allow the system to cool down to room temperature at a ramp rate of 1 &#176;C-2 &#176;C/min. Check for leaks referring to the RGA spectrum measured during the cool down.</li>
		<li>Analyze the residual gas in the sample chamber. Measure the RGA spectrum. Close the AVCh and measure the RGA spectrum again. The RGA spectrum of the sample chamber corresponds to the difference between the spectra acquired before and after closing the AVCh.</li>
		<li>Verify that the sum of all impurity gases, such as H2O, CO, and CO2, is below 5%; otherwise, repeat the bakeout again.</li>
	</ol>
	</li>
	<li>Operating the SRG 
	NOTE: Proper operation of the SRG is very important. Refer to the SRG operating manual for instructions.
	<ol>
		<li>Assemble the SRG head on the SRG flange assembly.</li>
		<li>Ensure that the axis of the SRG head is within &#177;2&#176; (max) (Figure 4). Use a level meter for reference.</li>
		<li>Start the SRG and wait for stabilization of the residual drag, a pressure-independent signal of the SRG, which usually takes a few hours.</li>
		<li>Enter the proper input parameters, such as gas (H2), temperature (24 &#176;C), and measurement interval (10 sec).</li>
	</ol>
	</li>
	<li>Procedure for initiating temperature control
	<ol>
		<li>While waiting for the signal to stabilize, stabilize the temperature of the sample. Switch on the chiller to run cooling water through the system. Set the fluid temperature to 15 &#176;C.</li>
		<li>Start the heater controller for the sample. Set the target temperature to 24 &#176;C. Wait for the temperature to stabilize within &#177;0.1 &#176;C after closing the door of the oven.</li>
	</ol>
	</li>
	<li>Procedure for acquiring the SRG signal
	<ol>
		<li>Verify that the variation of the offset value of the signal is within &#177;1 &#215; 10&#8722;9 Pa/sec; otherwise, disassemble the SRG from the system and change the rotor or flange assembly, then repeat 3.5-4.4. (If this is not possible, acquire the slope of the offset for 8-24 hr. This will be subtracted from the measured outgassing rate data.)</li>
		<li>Check the signal level provided by SRG controller; it should be at least &#8722;10 dB. Ideally, it should be between 0 and 6 dB. However, values of up to 12 dB are acceptable. If the signal is &#62;14 dB, stop the SRG operation. Detach the head and heat the thimble to 200 &#176;C. Repeat the entire operation starting from step 4.5.1.</li>
		<li>Check the damping level provided by SRG controller; the optimum value is between &#8722;35 and &#8722;60 dB, which is normally satisfied in the system using TMP and scroll pump which is laid on a rubber pad. Otherwise, stop all running equipment and remove sources of any mechanical vibration.</li>
	</ol>
	</li>
	<li>Acquiring the RoR data
	<ol>
		<li>Gently close the AV to start the pressure buildup. Be careful not to subject the SRG to a mechanical shock.</li>
		<li>Close the door of the oven and acquire pressure data for 8-24 hr using a computer.</li>
		<li>Precheck the measured data to verify that the variation in temperature is within &#177;0.1 &#176;C after stabilization and that the pressure rise is linear within 10% error. If these criteria are met, stop the measurement. Otherwise, continue to measure until the pressure rise becomes linear within 10% error for at least 16 hr.</li>
		<li>Turn off all equipment.</li>
	</ol>
	</li>
	<li>Calculation of the outgassing rate
	<ol>
		<li>Select the pressure set after the temperature stabilization.</li>
		<li>Fit the pressure rise data using linear least squares fitting and calculate the slope. The slope dP/dt is the measured rate of pressure rise after the valve is closed.</li>
		<li>Calculate the outgassing rate, q (H2 equivalent), using the equation 
		q = (V/A) (dP/dt) [Pa m3 sec&#8722;1 m&#8722;2], 
		where V is the volume of the sample chamber (m3) and A is the geometrical surface area of the chamber (m2).</li>
	</ol>
	</li>
</ol>

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The authors have no conflict of interest to declare.

Numerous methods for the measurement of outgassing rates have been reported in the literature. Experimental methods include the throughput, conductance modulation, two-path, RoR, and variations of these methods. However, no one method is ideal for obtaining the necessary outgassing data.10 The RoR method using SRG, however, became the method of choice for measurement of low outgassing materials.11-13 SRG17 is often used as a secondary standard in high vacuum systems without erroneous pump...

Steels are routinely used in construction because of their good mechanical properties. Certain steels (ferrous steels, in particular) are preferred materials for applications involving vacuum. Depending on the type and grade, these steels have sufficiently low outgassing rates essential for high vacuum (HV, 10&#8722;7 &#60; p &#60; 10&#8722;5 Pa) or ultrahigh vacuum (UHV, 10&#8722;10 &#60; p &#60; 10&#8722;7 Pa) systems. Further, extensive research has been conducted toward the development of special pretreatment procedures that reduce outgassing1-3. The pretreatment measures are designed to minimize the pumping investment or to improve the vacuum from HV to UHV or from UHV to extreme-high vacuum (p &#60; 10&#8722;10 Pa).
Although many practical methods have been proposed to reduce the outgassing rate of ferrous steels, recent methods are focused on reducing the time and temperature required to obtain a lower outgassing rate. Heat treatment at 350 &#176;C-450 &#176;C rather than vacuum firing at 800 &#176;C-950 &#176;C, is a good example of this approach.1,4,5 Furthermore, choosing the ideal material for a specific vacuum application is critical; for example, selecting a ferritic material with a very low outgassing rate for use in magnetic field shielding.6,7
During such investigations, precise measurement of the outgassing rate is a prerequisite for the screening of candidate materials or verifying the effectiveness of various pretreatment procedures.8,9 The most common experimental techniques used for the measurement of outgassing are the throughput and rate-of-pressure rise methods.10 Recently, various experiments have been conducted to measure the hydrogen outgassing rate based on the RoR method using spinning rotor gauge (SRG).1, 11-13 The RoR method using SRG is highly suitable for measuring very low hydrogen outgassing rates that often limit the lowest pressure achievable in a vacuum system made of steel. This is because the SRG has negligible pumping or outgassing action. Further, the SRG also has excellent accuracy and good linearity in high vacuum and ultra-high vacuum range.14
Given that the published literature on RoR experiments is limited, it is worthwhile to describe the experimental details to develop a deeper understanding of the method. In this video article, we describe in detail the process of setting up the experiment and provide detailed instructions to perform outgassing measurements using the RoR method. To demonstrate the efficacy of the method, the outgassing rates of two commonly used steels (stainless steel 304 and mild steel S20C) were measured before and after a preheat treatment to reduce the hydrogen outgassing rate. The pre- and post-treatment values were compared. Typical experimental results using a rather simple setup are presented to demonstrate the efficacy of the method optimized for evaluating low hydrogen degassing rates.

<table><tbody><tr><td>&lt;strong&gt;Sample chamber&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Stainless steel, 304</td><td>POSCO&lt;br /&gt;(www.posco.co.kr)</td><td></td><td></td></tr><tr><td>Mild steel, D3752</td><td>Xiangtan Iron&amp;amp;Steel co.,LTD (http://www.hnxg.com)</td><td></td><td></td></tr><tr><td>Mild steel, D3752</td><td>SeAh Besteel (www.seahbesteel.co.kr)</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Cleaning&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Cleaning bath</td><td>Samill IDS</td><td></td><td>Ultrasonic cleaning, heating, timer, concentration control&amp;nbsp;</td></tr><tr><td>Acetone</td><td>Samchun Chemical (www.samchun.com)</td><td>A1759</td><td>HPLC grade (99.7%)</td></tr><tr><td>Tekusolv</td><td>NCH Co.&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; (www.nch.com)</td><td>0368-0058J</td><td>Solvents</td></tr><tr><td>BN cleaner</td><td>Henkel surface technologies (na.henkel-adhesives.com)</td><td>6610263775</td><td>Alkaline, pH 13</td></tr><tr><td>Ethanol</td><td>Fisher Scientific (www.fishersci.com)</td><td>A995-4</td><td>HPLC Reagent (99.9%)</td></tr><tr><td>Deionized water (Electro deionizer SYSTEM)</td><td>A.T.A&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; (www.atagroup.co)</td><td>EDI SYSTEM</td><td></td></tr><tr><td>Liquid N&lt;sub&gt;2&lt;/sub&gt; gas</td><td>Hanyoung (www.gasmaster.co.kr)</td><td>B/T 176 L</td><td>LN&lt;sub&gt;2&lt;/sub&gt; dewar, purity 99.999%</td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Welding&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Tungsten Inert Gas wedling machine</td><td>Thermal Arc (www.victortechnologies.com/thermalarc)</td><td>400GTSW</td><td>Ar gas preflow and postflow 8 L/min, backflow 5 L/min</td></tr><tr><td>turning jig</td><td>Vactron&lt;br /&gt;(www.vactron.co.kr)</td><td>Made to order</td><td>Made to order</td></tr><tr><td>Ar gas</td><td>Lindekorea (www.lindekorea.com)</td><td></td><td>Purity 99.999%</td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Leak test&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Leak detector</td><td>Adixen&lt;br /&gt;(www.adixen.fr/en/)</td><td>ASM380</td><td>Pumping Speed (air): 9.7 L/sec</td></tr><tr><td>He gas</td><td>Lindekorea (www.lindekorea.com)</td><td></td><td>Purity 99.999%</td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Vacuum equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Spinning rotor gauge&amp;nbsp;</td><td>MKS Instruments (www.mks.com)</td><td>SRG-3</td><td>Controller, head, and thimble set</td></tr><tr><td>Oscilloscope</td><td>Tektronix&lt;br /&gt;(www.tek.com)</td><td>TDS2012B</td><td></td></tr><tr><td>Residulal gas analyser</td><td>Balzers</td><td>QMA200</td><td>m/e 0-100&amp;nbsp;</td></tr><tr><td>TMP (HiPace 80)</td><td>Pfeiffer Vacuum (www.pfeiffer-vacuum.com)</td><td>PMP03941</td><td>Pumping Speed (N&lt;sub&gt;2&lt;/sub&gt;): 67 L/sec</td></tr><tr><td>Scroll pump</td><td>Anest Iwata&lt;br /&gt;(www.anest-iwata.co.jp)</td><td>ISP 90</td><td>Pumping Speed (Air): 1.8 L/sec</td></tr><tr><td>All-metall easy close angle valve (CF35)</td><td>VAT Inc.&lt;br /&gt;(www.vatvalve.com)</td><td>54032-GE02-0002</td><td>Rotatable flange</td></tr><tr><td>Angle valve (KF25)</td><td>MDC Vacuum Inc. (www.mdcvacuum.com)</td><td>KAV-100</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Temperature control&amp;nbsp;&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Chiller</td><td>JEIO Tech&lt;br /&gt;(www.jeiotech.com)</td><td>RW-2025G</td><td></td></tr><tr><td>Cooling line</td><td>LS Metal&lt;br /&gt;(www.lsmetal.biz)</td><td>C1100</td><td>Level Wound Coil, Diameter 10 mm</td></tr><tr><td>Heater controllers</td><td>HMT</td><td>Made to order</td><td>Bakeout program controller</td></tr><tr><td>Electrical heater tapes</td><td>Brisk heat (www.briskheat.com)</td><td>BIH101080L</td><td></td></tr><tr><td>Thermocouple (K type)</td><td>miraesensor (www.miraesensor.com)</td><td>MR-2290</td><td></td></tr><tr><td>Handheld multimeter</td><td>Saehan&lt;br /&gt;(www.saehan.co.kr)</td><td>3234</td><td></td></tr><tr><td>Data recorder (Temp.)</td><td>Yokogawa (www.yokogawa.com)</td><td>GP10-1E1F-UC10</td><td></td></tr></tbody></table>

measurement of outgassing rates of steels

Steels are commonly used materials in the fabrication of vacuum systems because of their good mechanical, corrosion, and vacuum properties. A variety of steels meet the criterion of low outgassing required for high or ultrahigh vacuum applications. However, a given material can present different outgassing rates depending on its manufacturing process or the various pretreatment processes involved during the fabrication. Thus, the measurement of outgassing rates is highly desirable for a specific vacuum application. For this reason, the rate-of-pressure rise (RoR) method is often used to measure the outgassing of hydrogen after bakeout. In this article, a detailed description of the design and execution of the experimental protocol involved in the RoR method is provided. The RoR method uses a spinning rotor gauge to minimize errors that stem from outgassing or the pumping action of a vacuum gauge. The outgassing rates of two ordinary steels (stainless steel and mild steel) were measured. The measurements were made before and after the heat pretreatment of the steels. The heat pretreatment of steels was performed to reduce the outgassing. Extremely low rates of outgassing (on the order of 10&#8722;11 Pa m3 sec&#8722;1 m&#8722;2) can be routinely measured using relatively small samples.

As expected, the residual gas after the bakeout was mostly hydrogen.7 The pressure rise measured using the SRG was linear over a long period of time (Figure 5). Thus, the readsorption effect might be negligible and the intrinsic outgassing rate (q) for the steels tested in this study can be evaluated using the RoR method.10 The measured pressure rise data was analyzed using the linear least squares fitting method. The outgassing rates of the...

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Measurement of Outgassing Rates of Steels

A protocol for the measurement of outgassing rates of hydrogen from ordinary steel vacuum chambers using the rate-of-pressure rise method is presented.

Steels are commonly used materials in the fabrication of vacuum systems because of their good mechanical, corrosion, and vacuum properties. A variety of ...

measurement-of-outgassing-rates-of-steels

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11.5K Views.  POSTECH. A protocol for the measurement of outgassing rates of hydrogen from ordinary steel vacuum chambers using the rate-of-pressure rise method is presented.

Video: Measurement of Outgassing Rates of Steels

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

Environment

Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP)1. 
The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. 
The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments.

This article reports on a laboratory scale investigation of an existing field procedure and its adaptation for sealing of leaky wellbores. It consists of mechanical expansion of metal pipe, which results in an improved metal/cement bond, ultimate sealing of hydraulic pathways and prevention of gas leaks caused by the presence of a microannular channel.

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe ...

Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and potential mitigation treatments that can improve air quality in commercial deep-bedded mono-slope facilities. The model is dynamic and allows researchers to easily collect many chemical and physical measurements from the bedded pack. Weekly measurements, collected over the course of six to seven weeks, allows sufficient time to see changes in air quality measurements over time as the bedded pack matures. The data collected from the simulated bedded packs is within the range of concentrations previously measured in commercial deep-bedded mono-slope facilities. Past studies have demonstrated that 8 - 10 experimental units per treatment are sufficient to detect statistical differences among the simulated bedded packs. The bedded packs are easy to maintain, requiring less than 10 minutes of labor per bedded packs per week to add urine, feces, and bedding. Sample collection using the gas sampling system requires 20 - 30 minutes per bedded pack, depending on the measurements that are being collected. The use of lab-scaled bedded packs allows the researcher to control variables such as temperature, humidity, and bedding source that are difficult or impossible to control in a research or commercial facility. While not a perfect simulation of &#34;real-world&#34; conditions, the simulated bedded packs serve as a good model for researchers to use to examine treatment differences among bedded packs. Several lab-scale studies can be conducted to eliminate possible treatments before trying them in a research or commercial-sized facility.

A protocol has been developed to measure gases, odors, and nutrient composition in lab-scaled bedded manure packs, which can be used to study ways to improve air quality in commercial cattle facilities using deep-bedded manure packs.

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope ...

Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, prevent them and minimize the damages associated with them. One of the most important characteristics of corrosion processes is the corrosion rate. The measurement of corrosion rates is often very difficult or even impossible especially in less conductive, non-aqueous environments such as biofuels. Here, we present five different methods for the determination of corrosion rates and the efficiency of anti-corrosion protection in biofuels: (i) a static test, (ii) a dynamic test, (iii) a static test with a reflux cooler and electrochemical measurements (iv) in a two-electrode arrangement and (v) in a three-electrode arrangement. The static test is advantageous due to its low demands on material and instrumental equipment. The dynamic test allows for the testing of corrosion rates of metallic materials at more severe conditions. The static test with a reflux cooler allows for the testing in environments with higher viscosity (e.g., engine oils) at higher temperatures in the presence of oxidation or an inert atmosphere. The electrochemical measurements provide a more comprehensive view on corrosion processes. The presented cell geometries and arrangements (the two-electrode and three-electrode systems) make it possible to perform measurements in biofuel environments without base electrolytes that could have a negative impact on the results and load them with measurement errors. The presented methods make it possible to study the corrosion aggressiveness of an environment, the corrosion resistance of metallic materials, and the efficiency of corrosion inhibitors with representative and reproducible results. The results obtained using these methods can help to understand corrosion processes in more detail to minimize the damages caused by corrosion.

The testing of processes associated with material corrosion can often be difficult especially in non-aqueous environments. Here, we present different methods for short-term and long-term testing of corrosion behavior of non-aqueous environments such as biofuels, especially those containing bioethanol.

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, ...

Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas industry faces continued scrutiny for methane emissions from across the supply chain, due to methane&#39;s relatively high global warming potential (25-84x that of carbon dioxide, according to the Energy Information Administration). Currently, a variety of techniques of varied uncertainties exists to measure or estimate methane emissions from components or facilities. Currently, only one commercial system is available for quantification of component level emissions and recent reports have highlighted its weaknesses.
In order to improve accuracy and increase measurement flexibility, we have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases based on transportation emissions measurement principles. The FFS is a modular system that consists of an explosive-proof blower(s), mass airflow sensor(s) (MAF), thermocouple, sample probe, constant volume sampling pump, laser based greenhouse gas sensor, data acquisition device, and analysis software. Dependent upon the blower and hose configuration employed, the current FFS is able to achieve a flow rate ranging from 40 to 1,500 standard cubic feet per minute (SCFM). Utilization of laser-based sensors mitigates interference from higher hydrocarbons (C2+). Co-measurement of water vapor allows for humidity correction. The system is portable, with multiple configurations for a variety of applications ranging from being carried by a person to being mounted in a hand drawn cart, on-road vehicle bed, or from the bed of utility terrain vehicles (UTVs). The FFS is able to quantify methane emission rates with a relative uncertainty of &#177; 4.4%. The FFS has proven, real world operation for the quantification of methane emissions occurring in conventional and remote facilities.

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings. No significant change in surface micro-topography was detected using optical profilometry, however, statistically significant nanoscale changes to the surface were detected using atomic force microscopy. Analysis of the X-ray photoelectron spectroscopy and attenuated total reflection infrared micro-spectroscopy data revealed that degradation of the ester groups had occurred through exposure to ultraviolet light to form COO&#903;, -H2C&#903;, -O&#903;, -CO&#903; radicals. During the degradation process, CO and CO2 were also produced.

Two types of surfaces, polyester-coated steel and polyester coated with a layer of silica nanoparticles, were studied. Both surfaces were exposed to sunlight, which was found to cause substantial changes in the chemistry and nanoscale topography of the surface.

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, ...

Determining the Chemical Composition of Corrosion Inhibitor/Metal Interfaces with XPS: Minimizing Post Immersion Oxidation

An approach for acquiring more reliable X-ray photoelectron spectroscopy data from corrosion inhibitor/metal interfaces is described. More specifically, the focus is on metallic substrates immersed in acidic solutions containing organic corrosion inhibitors, as these systems can be particularly sensitive to oxidation following removal from solution. To minimize the likelihood of such degradation, samples are removed from solution within a glove box purged with inert gas, either N2 or Ar. The glove box is directly attached to the load-lock of the ultra-high vacuum X-ray photoelectron spectroscopy instrument, avoiding any exposure to the ambient laboratory atmosphere, and thus reducing the possibility of post immersion substrate oxidation. On this basis, one can be more certain that the X-ray photoelectron spectroscopy features observed are likely to be representative of the in situ submerged scenario, e.g. the oxidation state of the metal is not modified.

A protocol to avoid the oxidation of metallic substrates during sample transfer from an inhibited acidic solution to an X-ray photoelectron spectrometer is presented.

An approach for acquiring more reliable X-ray photoelectron spectroscopy data from corrosion inhibitor/metal interfaces is described. More specifically, ...

Chemistry

Applicability Analysis of Assessment Methods for Morphological Parameters of Corroded Steel Bars

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly dominate the safety and performance of an existing concrete structure. As a result, it is important to measure the geometry and amount of corrosion of a steel bar in a structure properly to assess the residual bearing capacity and service life of the structure. This paper introduces and compares five different methods for measuring the geometry and amount of corrosion of a steel bar. A single 500 mm long and 14 mm diameter steel bar is the specimen that is subjected to accelerated corrosion in this protocol. Its morphology and the amount of corrosion were carefully measured before and after using mass loss measurements, a Vernier caliper, drainage measurements, 3D scanning, and X-ray micro-computed tomography (XCT). The applicability and suitability of these different methods were then evaluated. The results show that the Vernier caliper is the best choice for measuring the morphology of a non-corroded bar, while 3D scanning is the most suitable for quantifying the morphology of a corroded bar.

This paper measures the geometry and the amount of corrosion of a steel bar using different methods: mass loss, calipers, drainage measurements, 3D scanning, and X-ray micro-computed tomography (XCT).

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly ...

Quantitative Analysis by Thermogravimetry-Mass Spectrum Analysis for Reactions with Evolved Gases

During energy conversion, material production, and metallurgy processes, reactions often have the features of unsteadiness, multistep, and multi-intermediates. Thermogravimetry-mass spectrum (TG-MS) is seen as a powerful tool to study reaction features. However, reaction details and reaction mechanics have not been effectively obtained directly from the ion current of TG-MS. Here, we provide a method of an equivalent characteristic spectrum analysis (ECSA) for analyzing the mass spectrum and giving the mass flow rate of reaction gases as precise as possible. The ECSA can effectively separate overlapping ion peaks and then eliminate the mass discrimination and temperature-dependent effect. Two example experiments are presented: (1) the decomposition of CaCO3 with evolved gas of CO2 and the decomposition of hydromagnesite with evolved gas of CO2 and H2O, to evaluate the ECSA on single-component system measurement and (2) the thermal pyrolysis of Zhundong coal with evolved gases of inorganic gases CO, H2, and CO2, and organic gases C2H4, C2H6, C3H8, C6H14, etc., to evaluate the ECSA on multi-component system measurement. Based on the successful calibration of the characteristic spectrum and relative sensitivity of specific gas and the ECSA on mass spectrum, we demonstrate that the ECSA accurately gives the mass flow rates of each evolved gas, including organic or inorganic gases, for not only single but multi-component reactions, which cannot be implemented by the traditional measurements.

Precise determination of the evolved gases&#39; flow rate is key to study the details of reactions. We provide a novel quantitative analysis method of equivalent characteristic spectrum analysis for thermogravimetry-mass spectrum analysis by establishing the calibration system of the characteristic spectrum and relative sensitivity, for obtaining the flow rate.

During energy conversion, material production, and metallurgy processes, reactions often have the features of unsteadiness, multistep, and ...

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of thermal runaway (TR), the exothermic decomposition reactions in anode and cathode were studied, using a Simultaneous Thermal Analysis (STA)/Gas Chromatography-Mass Spectrometry (GC-MS)/Fourier Transform Infrared (FTIR) spectrometer system. These techniques allowed the identification of the reaction mechanisms in each electrode, owing to the analysis of evolved gaseous species, the amount of heat released and mass loss. These results provided insight into the thermal events happening within a broader temperature range than covered in previously published models. This allowed the formulation of an improved thermal model to depict TR. The heat of reaction, activation energy, and frequency factor (thermal triplets) for each major exothermic process at material level were investigated in a Lithium Nickel-Manganese-Cobalt-Oxide (NMC (111))-Graphite battery cell. The results were analyzed, and their kinetics were derived. These data can be used to successfully simulate the experimental heat flow.

This work aims at determining the reaction kinetics of Li-ion battery cathode and anode materials undergoing thermal runaway (TR). Simultaneous Thermal Analysis (STA)/Fourier Transform Infrared (FTIR) spectrometer/Gas Chromatography Mass Spectrometry (GC-MS) were used to reveal thermal events and to detect evolved gases.

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of ...

Measurement of Outgassing Rates of Steels

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