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This is a problem from the engineering field, and it is expected to design appropriate adsorbents. Q1: How to design an O₂ selective adsorbent in a mixture environment of CH₄ (60%), N₂ (20%), O₂ (3 - 8%), C₂H₆ (5%), C₂H₄ (5%)? Q2: How to design a high - performance Ne selective adsorbent in the Ne/He system (the temperature can be reduced), and it is required to reduce Ne in high - purity He gas to the ppm level? Q3: How to remove various sulfur - containing compounds, thiols, carbonyl sulfide, etc. in the coal/petroleum industrial gas system?
Q4: Design a low - partial - pressure - selective adsorbent in the high - purity electronic specialty gas system, with the requirement of removing impurities to the ppb level.
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It depends on the concentration, but using a membrane is an option.
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I want to know more about gas reservoirs in world.
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It is affected by so many factors. First of all, it needs to be an old formation, affected by high temperatures, produced gas must be trapped by surrounding formations, low inorganic/high organic matter content, vein or seam needs to be thick, burial depth should be high etc. When all of these factors and some others combined, I think an anomaliously high gas containing unconventional reserve might exist.
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I want to know more about gas and oil reservoirs in Iran.
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I think it can be possible.
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I want to know more about gas and oil reservoirs in Iran.
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I think it is possible.
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In the LIBS experiment, if I want to detect methane gas, how do I know that this is the spectrum of methane without knowing that it's methane gas.
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If you want to identify specific CH₄ characteristics from your recorded LIBS spectra, from what I can see, there are two main approaches:
Using atomic emission lines:
  • For C, the 247.88 nm emission line is commonly used
  • For H, consider the Balmer series, particularly: Hα at 656.3 nm (frequently used), Hβ at 486.1 nm, and Hγ at 434.0 nm
Hence, by analyzing the C:H intensity ratio from the LIBS spectra, you can determine whether it is consistent with methane's molecular structure (1:4). Note that, due to various experimental factors, the LIBS intensity ratio would likely deviate from the exact 1:4 ratio. Therefore, it is necessary to establish baseline ratios by developing a calibration curve from known methane concentrations. From this calibration, a correction factor can be derived as follows: (C:H = 1:4) / (IC:IH).
Using diatomic molecular bands:
  • C2 Swan Bands; Δv = 0 band around 516.5 nm, Δv = +1 band around 473.7 nm, and Δv = -1 band around 563.5 nm.
  • CH Bands; A²Δ → X²Π around 431.4 nm, B²Σ- → X²Π around 387.1 nm, and C²Σ+ → X²Π around 314.5 nm
The intensity ratios of these molecular bands can also provide insight into methane presence and concentration.
Additionally, consider the detector time delay at which these spectra are recorded: diatomic molecules recombine later (typically, of the order of a few tens of microseconds) than atomic species. Thus, optimizing the gate delay of your LIBS detection system is crucial to achieving reliable results.
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I want to know more about gas and oil reservoirs in world.
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Mesozoic era
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In LIBS experiments measuring gases, it is not known how to determine whether this is the spectrum of the measured gas, if the type of gas is not known.
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Dear Qing Xing Peng, To identify the plasma emission spectrum of unknown gases in Laser-Induced Breakdown Spectroscopy (LIBS), compare the observed spectrum to standard reference spectra of known gases. Databases like NIST’s Atomic Spectra Database provide emission lines and intensities for elements in various states. By matching prominent emission peaks with these reference spectra, the gas can be identified. For increased accuracy, use software tools or spectral libraries specifically tailored to LIBS, which often include algorithms for spectrum matching and gas identification.
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Dear Sir/Madam,
Kindly help me with this doubt, I am injecting 50 PPM H2 gas standard for the calibration of 1 mL (1000 micromole). I need to convert this PPM to micromoles kindly help me.
Thank you,
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In the gas phase, mol% is equivalent to volume%. If you need ppm v/v you do not need any conversion. If you need ppm m/vol, you use the molecular weight to convert H2 mol into mass
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Without changing catalyst (ZN)
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It can be done in the presence of unchanged catalyst
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I would like to include an internal standard in my method for testing ethylene, CO₂, and O₂ using gas chromatography (GC). I am currently using helium (He) as the carrier gas and nitrogen (N₂) as the makeup gas, with a Porapak Q and Molecular Sieve (Molsieve) column setup. An FID detects the ethylene, and a TCD detects CO₂ and O₂. Could you please advise me on choosing an appropriate internal standard and how to approach the calibration process, including the internal standard? Additionally, I’ve read about the use of Tedlar bags for gas sampling, but I am unsure of how these bags work. Could you provide some guidance on this?
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Thank you!
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We are milling highly reactive materials such as Sm or Ti under Ar gas purging into it. Still oxidation occurs during the milling process.
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Compeletely purging a milling cell from atmosphere is problematic indeed. Solution depends on number of prenumatic connections with argon.
I used a ring mill with 'single' pneumatic connection and I only diminished the oxidation. But I couldn't compeletely eliminated. I used 5 bar of argon. I fill the chamber, closed the valve, removed the pneumatic hose, open the valve to release the gas inside of chamber, close the valve immediately, put pneumatic hose again, apply 5 bar of argon and fill the chamber. I repeated this procedure 5 times for my purpose. It decreased the oxidation to negligible levels but it didn't compeletely elimate it. If you don't require to work with a lot of samples like mysely, I suggest repeat the cycle 10 or 15 times. If your single connection can reach every part of chamber, I mean such as over filling of your chamber with too much sample prevent argon gas to reach everywhere, this procedure will decrease oxygen amount 20 % of it each time. Therefore, 5 cycles mean decreasing atmosphere to 0.032 % of volume.
If your grinding cell has two connections, one inflow and one outflow, I think problems might occur due to excessive sample mass and/or small deadend spots decrease flow velocity. Perhaps purging longer durations with this system and opening and closing the flow to allow diffusion to influence those deadend locations might solve your problem.
I hope this answer help you with your problem.
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Hi everyone I'm a student working on my final year project.. I would appreciate if someone can assist me in finding a way to measure ethylene levels in gas in ppm
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I think best way is using a gas chromatograph equipped with flame ionization detector(FID). It can even give ppb values with 2-3 % error by employing proper setup. However, it operates cyclic, so that is a drawback if you want to obtain instantaneous value such as from a pipeline in some plant or a mine air sample. But, the device can be adjusted to automatically collect sample and restart after an experiment so it gives data for every 2 to 30 minutes depending on the setup.
Another way is using a sensor. It can perfectly collect data for each second or it can be made to collect hundereds per second. The drawback is sensors usually produce signals for many other gas compounds. Therefore, you need to make sure there isn't any other gas compounds around that it produce signal. They may require calibration after excessive concentration, temperature, pressure etc. They require calibration anyway after 3-6 months. Their precision can be poor.
Both methods require a lot more assessment and design. But, I think you can complete rest of your final year project with this start and a little bit research.
There are also other ancient ways for this kind of measurements.
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I am working on heat pipe two phase simulation.In this density variation with temperature is an important parameter. I do not encounter any problem in my simulation if i opt constant vapor density, however when i go for ideal gas or polynomial (density variation) i am getting floating point exception error.. How to avoid this problem without changing density variation(ideal gas).
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Hello. I've problem floating point exception ansys fluent error in a project of analysis of an airfoil in air. My problem was a key point that I should set the air as ideal gas and it worked perfectly.
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I understood it in 29 years work in field works.
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Oil and gas often to be in anticlinal zone. But if we see thinking about migration that oil reservuare will be if there have sandstones
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What is the Wobbe Index, also known as the Wobbe Number or Wobbe Value ?
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what is wobbe number for producer gas obtained from co co gasification using air as gasifying agent
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For those upgrading in petroleum engineering or department of chemical engineering
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According to several sources consulted, scoring high in engineering drawing for the oil and gas industry requires combining technical skills, attention to detail, and a solid understanding of industry standards. Here are some tips to help you excel:
  1. Understand the Basics: Make sure you have a strong grasp of fundamental engineering drawing principles, including orthographic projections, isometric drawings, and sectional views.
  2. Learn Industry Standards: Familiarize yourself with the specific standards and symbols used in oil and gas engineering drawings, such as Piping and Instrumentation Diagrams (P&IDs) and Process Flow Diagrams (PFDs)1.
  3. Practice Precision: Accuracy is crucial in engineering drawings. Ensure all dimensions, scales, and annotations are precise and clear. Double-check your work to avoid errors.
  4. Use the Right Tools: Proficiently utilize CAD software. Tools like AutoCAD, SolidWorks, and others are essential for creating detailed and accurate drawings.
  5. Stay Updated: The oil and gas industry is constantly evolving. Stay up to date with the latest technologies, materials, and methods used in the field.
  6. Seek Feedback: Regularly seek feedback from instructors or professionals in the field. Constructive criticism can help you identify areas for improvement.
  7. Study Real-World Examples: Analyze existing engineering drawings from actual projects. This can provide insights into best practices and common pitfalls4.
  8. Focus on Clarity: Your drawings should be easy to understand. Use clear labels, consistent symbols, and a logical layout to convey information effectively.
  9. Understand the Process: Gain a thorough understanding of the processes and equipment used in the oil and gas industry. This knowledge will help you create more accurate and relevant drawings.
  10. Continuous Learning: Engineering is a field of continuous learning. Attend workshops, take additional courses, and stay curious about new developments in the industry.
Combining these strategies, you’ll be well-equipped to produce high-quality engineering drawings and score high in your assessments.
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I want to know more about gas and oil reservoirs.
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The best conditions for the formation of oil and gas are the presence of a suitable hydrocarbon system, including source rock, reservoir rock, and cap rock.
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I want to know more about gas and oil reservoirs in Iran.
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Yes, the Qom Formation has been identified as a hydrocarbon reservoir.
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I want to know more about gas and oil reservoirs in Iran.
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Yes, it is possible to form oil and gas in any place in Iran where the oil system is suitable.
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Hello,
Can anyone provide me with the absorption coefficient of methane gas at 7.7 um? Any reference?
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Careful, there are natural and decadic logarithmic coefficients, as I mentioned in my post above. Which one is this and what qualifies it as "correct" for you?
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There are anaerobic gas pak jars and environment providers in the laboratory that provide anaerobic environmental conditions for the growth of anaerobic bacteria. However, there is no anaerobic chamber to transfer anaerobic bacteria. Do you have any advice for this?
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Songül Gönel Inoculating anaerobic bacteria without a nitrogen or argon gas stream requires careful handling to maintain an oxygen-free environment. Here are some alternative methods:
1. Use a glove box: Inoculate in a glove box filled with oxygen-free gas, like nitrogen or argon.
2. Anaerobic chamber: Use a portable anaerobic chamber or a vinyl anaerobic bag.
3. Oxygen-free water: Use oxygen-free water or medium to rehydrate the bacteria and prepare the culture medium.
4. Aspirate and inject: Use a syringe to aspirate the inoculum and inject it into the culture medium, minimizing exposure to air.
5. Butyl rubber-stoppered tubes: Use tubes sealed with butyl rubber stoppers, which are impermeable to oxygen.
6. Hungate tubes: Use Hungate tubes, which have a specialized stopper and technique to maintain anaerobic conditions.
7. Anaerobic broth: Use anaerobic broth, which contains reducing agents to maintain an oxygen-free environment.
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List down the various factors responsible and how does this effect the overall biogas production when it is related to Hydraulic retention time of the digester based on the feedstock?
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Bruno Peeters I am of the same view when it comes to CSTR non mixing digesters vs mixing systems and this is the reason I support and suggest to have good mixing systems in place to start with. I agree with the HRT/SRT vs biogas production details you have shared.
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It is known that cooking or domestic gas is composed of chief components like propane and butane. Recent discovery have shown water being present in dometic gas cylinders (locality is confidential). Is the reaction of water and propane or butane gas feasible? Should the presence of water in these cylinders be a call for concern or a it is another innovation to science. Is it just a means for fast cash by local producers or sellers of domestic gas? Please this scenario is fast spreading and creating panic. I need your contribution.
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Water cannot be used as cooking because it doesn't contain carbon and it is not a supporter of combustion.
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I need to measure the H2S gas from my batch reactors; eventually, the available device for checking is a UV-vis spectrophotometer. Is it possible to measure the gas with it?
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Measuring hydrogen sulfide (H₂S) gas using a UV-Vis spectrophotometer involves a specific method because H₂S itself is not directly measurable by UV-Vis spectroscopy due to its low absorption in the UV-Vis range. Instead, you typically use a chemical reaction that converts H₂S into a compound that can be detected by UV-Vis spectroscopy. One common method is the iodometric method, which involves reacting H₂S with iodine to form a colored complex that can be quantified.
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Underground Hydrogen Storage (UHS) in Aquifers
1. Since, hydrogen no more directly exists as a gas, how easy would it remain to separate hydrogen, either from water, or, from fossil fuels, despite its abundance in the universe?
2. Whether subsurface hydrogen(H2) storage has been tested in a commercial-scale environment – either in deep saline aquifers, or, in depleted oil/gas reservoirs (apart from salt caverns, practiced in Texas/UK), where, temporarily stored hydrogen has been produced back on demand?
3. Whether, saline aquifers, and/or, oil/gas reservoirs, towards H2 storage, is expected to ensure sustainability and resilience of the planned clean hydrogen economy in order to meet the global de-carbonization goal?
4. In the absence of H2 storage, in a thick, porous and permeable saturated subsurface formation (like a salt cavern), will we be able to satisfy required storage capacity and sufficient injectivity for acceptable well operating rates – either in saline aquifers, or, depleted oil/gas aquifers?
5. Whether, UHS is expected to provide storage capacity in order to balance seasonal supply and demand fluctuations; and also, to meet peak demand towards stabilizing the power grid?
6. How exactly to handle
(a)        The enhanced physical risk of hydrogen leakage (higher tendency of H2 to spread laterally in a porous reservoir increases the probability of escape of the stored H2 either through the abandoned/leaky wells or through the leaking faults)?
(b)       Reduced recoverability of stored H2 product – either in depleted oil/gas reservoirs, or, in deep saline aquifers – given the fact that the H2 remains associated with reduced viscosity and enhanced diffusivity (with reference to natural-gas)?
7. Unlike the minimum requirement of cushion gas in salt caverns, to what extent, cushion gas (employed to ensure sufficient pressure maintenance and adequate withdrawal rates) gets factored into the subsurface storage costs in saline aquifers and depleted oil/gas reservoirs?
8. Towards storing hydrogen in depleted oil/gas reservoirs, how easy would it remain to handle the dynamics of reservoir wettability (that impacts H2 injection and storage); viscous fingering (providing means for hydrogen loss); and the reactivity of H2 with the organic constituents of depleted oil/gas reservoirs (including kerogen, residual hydrocarbons and microbes – leading to H2 losses resulting from chemical or microbial interaction)?
9. Whether the greater compressibility of a cushion gas would really improve the H2 production rate @ the end of a production cycle
? 10.                  Whether the application of standard diffusion models would remain to suffice towards the estimation of the amount of H2 lost through dissolution into formation brine; and diffusing away from the aquifer of interest into the overlying caprock?
Suresh Kumar Govindarajan
Professor (HAG)  IIT-Madras
25-July-2024
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The statement "Since hydrogen no more directly exists as a gas, how easy would it remain to separate hydrogen, either from water, or from fossil fuels?" touches on a critical aspect of hydrogen production and its separation from other compounds. Here’s a detailed discussion:
Hydrogen Production and Separation
1. Hydrogen from Water:
  • Electrolysis:
    • Process: Electrolysis involves passing an electric current through water to separate it into hydrogen and oxygen gases.
    • Efficiency: The efficiency of electrolysis is a key factor. Modern electrolyzers can achieve efficiencies of around 70-80%.
    • Renewable Energy: If powered by renewable energy sources (e.g., solar, wind), electrolysis can produce green hydrogen, which is environmentally friendly.
    • Challenges: The cost of electricity is a major factor influencing the economic viability of electrolysis. The initial setup and maintenance of electrolyzers can also be costly.
2. Hydrogen from Fossil Fuels:
  • Steam Methane Reforming (SMR):
    • Process: SMR is the most common method of producing hydrogen. It involves reacting methane (natural gas) with steam at high temperatures to produce hydrogen and carbon monoxide. A subsequent reaction (water-gas shift reaction) converts carbon monoxide to carbon dioxide and more hydrogen.
    • Efficiency and Cost: SMR is relatively efficient and cost-effective, making it the predominant method for industrial hydrogen production.
    • Environmental Impact: The process releases significant amounts of CO₂, contributing to greenhouse gas emissions unless carbon capture and storage (CCS) technologies are used.
  • Coal Gasification:
    • Process: Involves reacting coal with oxygen and steam at high temperatures to produce a mixture of gases (syngas) from which hydrogen can be separated.
    • Challenges: This method is less efficient and more polluting compared to SMR. It also requires substantial capital investment.
Technological and Economic Considerations
1. Advancements in Technology:
  • Electrolyzers: Continuous improvements in electrolyzer technology (e.g., proton exchange membrane electrolyzers, solid oxide electrolyzers) are making the process more efficient and cost-effective.
  • Carbon Capture: Advances in carbon capture and storage (CCS) can mitigate the environmental impact of hydrogen production from fossil fuels.
2. Cost Factors:
  • Capital Costs: Initial setup costs for both electrolysis and fossil fuel-based hydrogen production can be high.
  • Operational Costs: These include the cost of electricity for electrolysis and the cost of raw materials (natural gas or coal) for SMR and gasification.
  • Economies of Scale: Larger production facilities can achieve lower per-unit costs, making hydrogen more affordable.
3. Environmental and Policy Considerations:
  • Regulations and Incentives: Government policies and incentives for clean hydrogen production (e.g., subsidies, carbon taxes) can influence the economic viability and adoption rates of different hydrogen production methods.
  • Sustainability: The choice of production method impacts the sustainability of hydrogen as an energy carrier. Green hydrogen (from electrolysis using renewable energy) is more sustainable compared to grey hydrogen (from SMR without CCS) or brown hydrogen (from coal gasification).
Conclusion
Separating hydrogen from water via electrolysis and from fossil fuels through methods like steam methane reforming remains feasible but involves distinct challenges and considerations. Technological advancements, economic factors, and environmental policies will play crucial roles in determining the ease and efficiency of hydrogen production. As the world moves towards cleaner energy sources, the focus is likely to shift more towards sustainable methods like electrolysis powered by renewable energy.
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Will it be scientifically correct to follow the close chamber technique of gas sampling from a pot experiment that is particularly used to collect gas samples from field experiments. What are the basic precautions that must be undertaken to carry out the process?
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Yes.
If the gases are obtained from cylinder pots, the heavy cylinder pots must be handled safely.
Staff must be instructed in the correct use of regulators and for hydrogen the needle valve.
For the porous pot to be used with hydrogen, the glass tube could be part of the manometer.
For the pot to be used with carbon dioxide, a rubber tube needs to connect to a manometer.
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how much efficient
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Regular grass can produce Methane gas. Nevertheless, the quality and ratio of methane gas to CO2 and other gas might be very small that combustion may not be possible.
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I am testing lipase activity for certain test strains however my negative control strain which is clostridium difficile did not show any growth in 24 hours of incubation at 37 degrees. The incubation is done using a CO2 gas chamber.
We are analyzing lipase activity using TWEEN OPACITY TEST. So far clostridium difficile within 24 hours has shown no signs of growth on the media. Is there any other bacterial strains that can be used as negative control for Tween Opacity Test.
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I am not sure we use the same test, but we work with various species of dairy Lactobacillus and they do not show lipase clearance zones on agar plates.
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I'm trying to figure out how to calculate leak rate for various materials used for elastic vacuum seals (such as Viton) from permeation coefficient K. I'm basing this on values from a paper referenced below. The units provided in the paper are m2 s-1 hPa-1. A similar combination of unit I have seen is cm3 cm/cm2 s-1 atm-1.
Leak rate is then F = K A (p1 - p0) / d, where A is exposed area of the seal, d is the thickness of the seal, and (p1 - p0) is the pressure differential. Since I'm dealing with vacuum systems, this can be assumed to be 1 atm (~1000 hPa). The A / d term is the reason for the cm / cm2 portion of the units combination, or if you combine all the distance units, you get something like m2.
Where I get confused is if you work through this equation, you end up with m3 / sec. However, leak rates are usually stated with units such as Torr liter / sec. Which makes sense, because the pressure-volume product defines a molecular quantity of gas (it's the left-hand side of the Ideal Gas Law, PV = nRT). Specifying just the volume is meaningless. So there is a quantity of pressure missing somewhere?
Sometimes, I see the units include "std" - what is this unit in reference to?
Thanks for the all help!
Paper: Journal of Geophysical Research (2004) vol 109, D04309, "Permeation of atmospheric gases ..." by P. Sturm et al.
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I have came across the exact same issue. Did you happen to figure out why the pressure component was missing from the leak rate 'F'?
Thanks
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Have you encountered a CAR1 AFC control irregularity error with Shimadzu's GC instrument? Manual states that there is a problem with carrier gas supply and advises to contact service. Could not find any leaks with a leak meter but could this be cause of a leak in the inlet? I am running a Frontier 3030 pyrolyzer with the GCMS.
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There was most probably a leak either in the inlet or the pyrolyzer, as the problem was fixed by tightening the connections.
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WHICH TECHNIQ (MASS SPECTROMETRY AND ËLECTRON IMPACT IONIZATION"IS BETTER TO ANALYZE H2 IN EXHAUST GAS
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Comparison and Recommendation: For Analyzing H₂ in Exhaust Gas:
Electron Impact Ionization (EI): When used with mass spectrometry, EI offers detailed and sensitive analysis of H₂ due to its consistent ionization properties. This makes it particularly effective for detecting and quantifying hydrogen specifically.
Mass Spectrometry (MS): As a standalone technique, MS is highly effective for analyzing various gases in exhaust emissions, including hydrogen. When paired with appropriate ionization methods like EI, it becomes a powerful tool for comprehensive exhaust gas analysis.
Recommendation:
Mass Spectrometry with Electron Impact Ionization (EI) is the superior choice for analyzing H₂ in exhaust gas. This combination utilizes the high sensitivity and specific ionization characteristics of EI along with the versatility and precision of MS, making it ideal for detecting and quantifying hydrogen in complex gas mixtures like exhaust emissions.
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Let us say that I have an equation of state for a non-ideal gas (i.e. the Vanderwaals equation). I would like to calculate the internal energy of the gas U(V,T) without any 'microscopic input'.
1) Is that possible?
2) If so, how should this be done?
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Henk Huinink, we could use Density Functional Theory to computationally determine the total energy and electron density distribution of the offending non-ideal gas (there are geniuses out there mastering DFT, which by the way is very amusing to me). Then, we could link the total energy derived from DFT to the macroscopic variables P, T, and V. Maybe using some ML method could help make sense of these relations?.
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explain the calculations
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You may consider 100 ppm as volume ratio of hydrogen in the gas mixture. If we assume most gases occupy 22.4 lit per gmol, then 100 ppm is (100*10 power minus 6/22.4) will be gmol of hydrogen in the mixture. In terms of micromol, we can multiply by 10 power 6. So overall 100 ppm will be 4.5 micromol
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According to my research: the core of the sun is formed among gas masses. The formation of nuclei is initially by nuclear fusion. The collision of nuclei creates larger nuclei.
When the volume of the gas mass decreases, the volume of the core remains constant. In the core of the star, nuclear fusion stops completely.
I discovered a new nuclear model. This model is common to atoms and stars.
In my model, instead of nuclear fusion in the sun, other methods are used. These methods correspond to all the characteristics of the stars from the birth of the star and answer many mysteries.No nuclear explosions occur in the Sun's core, while the heat inside can reach such a level that the entire core disintegrates.
I prepared an article in which: the birth of a star to the death of a star is described. With all the details, with mathematical formulas. My method is classic. It is not quantum or theoretical.
Recently I noticed that the rotation speed of the sun's crust is slowing down compared to the rotation speed of the sun's core. I calculated the size of the inner core of the sun.
The radius of the inner core of the sun = 131000
The volume of my discoveries is large. in different elements of space and methods of nuclear enrichment and... and all based on my nuclear model. I have about 50 articles.How can I present my discoveries?
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They say that the giant sun turns red and pulls the earth into itself.
According to my calculations, this will not happen.
For some reason I can't explain right now, as the Sun gets bigger, the distance between the rings around the Sun increases. And the distance between the planets and the sun is getting bigger.
When the Sun becomes a red giant: Earth's distance from the Sun is approximately equal to Jupiter's current distance. And unfortunately, the last rings of the Sun will be so far away that all the planets and their moons will be ejected.
In an article, I explained all the events of the star from birth to death.
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We use ... Desktop sputter coater device
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Ms Tuhmaz,
I think that my answer to this exact same question last month is still appropriate - where was it deficient?
From March 28th:
"Dr Tuhmaz,
It goes to wherever your vacuum pump exhausts to.
In most cases, that is the atmosphere (via an oil mist-trap: if on a rotary 'roughing' pump). Simply follow the line from the last pump's exhaust.
<a UHV rig will have a roughing pump after a turbo pump - it might be a diaphragm pump, a scroll pump, or a rotary pump - no matter what type, the argon will be sent to wherever that last pump delivers it>
Ah: a sputtering chamber - well, that's a relatively poor vacuum (depending on the size of that chamber - but in any case the argon probably vents to the laboratory via a filter or two. It would be hard, but not impossible, to sequester it."
A related question is, where *should* it vent to.
And the proper answer is, as Dr Weippert wrote, "to the outside".
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Is it possible to produce a very small amount of volatile oil along with condensed gas? If so, could you please provide a real example? Thank you.
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Thank you very much for your reply.
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Dear all,
After checking DSC and TGA analysis for ZIF-8 samples, it was possible to observe an endotermic peak at around 50ºC, using DSC under N2, and a weight loss in TGA at around 38ºC and 125ºC using He gas. It was checked that there was no impurities in the sample analyzed ( ZIF-8). Is is possible at those low temperatures to eliminate gas/ water trapped, or you suggest another process?.
Thanks in advance for your response/clarification
Kind regards
Rosa M Huertas
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Based on the DSC and TGA analyses you've Rosa María Huertas Penela provided for ZIF-8 samples, it appears that there is potential for desorption of gases and water within the temperature range of 30ºC to 60ºC. The endothermic peak observed around 50ºC in the DSC analysis and the weight loss in TGA between 38ºC and 125ºC indicate that there might be gas and water molecules trapped within the ZIF-8 structure.
Given this data, desorption could indeed occur within the specified temperature range. However, it's essential to consider the specific application and the desired level of desorption. If complete desorption is necessary, additional techniques or higher temperatures may be required.
In terms of suggestions for another process, I would recommend exploring techniques such as thermal cycling or vacuum treatment to enhance desorption efficiency. These methods could complement the temperature range you've mentioned and help achieve the desired level of gas and water removal from the ZIF-8 structure.
Overall, based on the provided data, desorption of CO2, N2, or water in ZIF-8 between 30ºC and 60ºC seems feasible, but further optimization and experimentation may be needed to achieve optimal results for your Rosa María Huertas Penela specific application.
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Hi,
 I'm using Brooks mass flow controller 5851E with Brooks control and readout unit 0152E. The differential pressure is set at 15 psi. Even though the set point is zero at the control unit, the mass flow controller lets through the gas. I cannot completely stop the gas flow, it still shows 2.5% on the control unit when the set point is at 0.
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Interestingly enough, I have the same problem but with another model of Brooks thermal mass flow controller.
The only way I could completely stop the gas flow is by closing the valve before the controller.
Also, to be fair, Brooks specifies in the manual that the controller readings can be trusted only when the gas flow rate is bigger than 10% of the set point mass flow rate.
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rGo by heating GO
sample is getting out by tube
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Argon soygaz olduğu için numune üzerinde radyoaktif veya kimyasal tepkime verir.
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As Prem said, the gas is generally not discarded as the energy content can be significant and therefore combusted and used to heat the process indirectly. No advanced system would just dump the gas. Initially during startup before steady state is achieved, then the low quality gases might be discarded, but they should be flared or passed through a thermal oxidiser.
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I need an oil that is inert to Gallium
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Try paraffine (= pure alkane) oil; they should be inert to gallium up to 200 °C, provided that no oxygen is present.
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Sputter coater
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Ghazal,
It goes to wherever your vacuum pump exhausts to.
In most cases, that is the atmosphere (via an oil mist-trap: if on a rotary 'roughing' pump)
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If liquid crystals represent a bridge from the solid state of matter to the liquid state. Is there a bridge between the liquid state and the gaseous state of matter?
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A liquid crystal is not exactly a bridge between solid and liquid states.
Actually, there is an ambiguity defining the two states. If one defines a solid by crystalline long range order (static, structure), liquid crystals are on the solid side. Instead, if one makes the distinction by viscosity or a (relatively arbitrary) relaxation time (dynamics), liquid cystals are liquid. Conversely, glasses are liquid or solid, repectively.
The common distinction between solid and liquid states is the dynamic definition. Then, glasses are "solid" and liquid crystals are ... "liquid"!
In theory, instead, glasses are studied within the formalism of liquid theory because presence or absence of periodicity induces important differences.
Beyond a critical point, a fluid shares properties of liquids (e.g. high density) and gases (absence of free surface).
There are other common intermediate states, like gels, emulsions, plymer melts, ...
Every classification is partly arbitrary...
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I am new to NANDA, so it seems like a basic question for nursing fellows. Could you explain when to choose the NANDA priorities, for example, in patients with ARDS or COPD on mechanical ventilation? It seems the clinical indicators are almost the same, requiring the result of arterial blood gas.
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Decision Making Between Nursing Diagnostic Priorities
Impaired Gas Exchange:
  • Focuses on oxygenation and carbon dioxide elimination at the alveolar-capillary membrane.
  • Signs and symptoms include dyspnea, cyanosis, altered mental status, and restlessness.
  • Conditions linked to impaired gas exchange are pneumonia, ARDS, pulmonary oedema, asthma, and COPD.
  • Nursing interventions involve oxygen optimization, positioning for ventilation, oxygen saturation monitoring, and respiratory treatment assistance.
Impaired Spontaneous Ventilation:
  • Concerns mechanical breathing problems like ineffective patterns or weak respiratory muscles.
  • Signs and symptoms consist of hypoventilation, shallow breathing, and increased work of breathing.
  • Conditions that may result in impaired spontaneous ventilation are neuromuscular disorders, spinal cord injuries, drug overdose, and CNS depressant effects.
  • Nursing interventions revolve around assisting ventilation efforts, keeping airways clear, providing respiratory treatments, ventilatory support if necessary, and monitoring respiratory rate.
When Choosing Between These Diagnoses:
  • Consider assessment findings like vital signs, lung sounds, and oxygen saturation levels.
  • Factor in underlying conditions and the severity of the patient's respiratory status.
  • Collaborate with the healthcare team for comprehensive assessment and management.
Individualized Care Plans:
  • Customize care plans based on the patient's condition and priorities identified through assessment.
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Gas diffuses into vacuum, dQ=0, thermodynamic entropy dS=dQ/T=0. The second law of thermodynamics cannot be calculated.Please refer to the attached diagram for details。
"Ds=dQ/T" is defined as a reversible process that can be used, but an irreversible process that cannot be used. This violates the universality and consistency of natural science.
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The formula change in S = dQ/T refers to a particular case, that of simple thermal heating. The expansion of an ideal gas into a vacuum involves no change in energy, so this formula does not apply to that case.
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Dear connections, I’m currently searching for a PhD/Research position in the field of “Energy Transition”, with a strong interest in Energy Systems Analysis & Modeling as well as Clean Energy Technologies (EV,..). My research track is in the field of energy market analysis & forecast using AI. In my M.Sc. thesis at The American University in Cairo, I managed to build an energy planning model using different ANN topologies, that will help in securing the balance between the energy supply and demand in the United Kingdom for different end-use sectors; domestic, industrial, transport, and services sectors. I also carried out a long-term forecasting for the UK's final energy consumption up to the year 2035, and analyzed the results comparing to the outlook of the UK’s governmental department of Business, Energy & Industrial Strategy (BEIS). Being a Future Energy Leader at the World Energy Council and an energy transition advocate, I understand the importance of humanising energy and contributing to the global dialogue on energy and sustainability issues. On the other hand, I have 11 years of professional experience in the oil and gas, refining, and petrochemical industries at Enppi, one of the leading engineering and EPC main contractors in the Middle East and Africa. I am definitely open to expanding my career path in other "Energy Transition" fields of research, and open for relocation, if the PhD requires so. Please let me know if there are any potential openings. Thank you.
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Greetings Haidy,
Have you checked the Energy and Resources Ph.D. Program at the University of California, Berkeley? It could be an option. You have both professional and research experience in the energy field.
Best regards,
Marx
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I am trying to calculating the amount of adsorption of specific gas from a mixture of gases on a adsorbent(solid material)like zeolite, activated carbon. The adsorption process takes place by varying the pressure(Pressure swing adsorption).
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The adsorption of gases on solids depends on the activation of the solid absorbent. The adsorption capacity is measured using static or dynamic methods. The static method is based on determining the difference between the concentration of the adsorbed component in the initial solution and in the solution, which is in equilibrium with the adsorbent.The formula Qe = (C0 − Ce) × V/m was used during the test to calculate the adsorption capacity. Here, C0 and Ce are the concentrations of Sb(III) before and after the adsorption, mg L−1, respectively; V is the volume of the Sb(III) solution, mL; m is the adsorbent dosage, mg. Isothermal adsorption test.
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Hi, I have some problems with detection of CO2 by GC-TCD molecular sieve 5A. I used nitrogen as carrier gas and i did not get any pick for CO2.( but I know I have at least 5 percent CO2 I have analysed gas by gas analyser).
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Molecular sieve 5A should not be used for CO2 analysis due to the reaction of CO2 with the stationary phase.
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Gas radiation has no thermal equilibrium, and the second law of thermodynamics is invalid. The following pictures are all from the content of heat transfer and university physics, combined together, it is found that the second law of thermodynamics is invalid.
Please refer to the picture for details.
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Three formulas can explain that gas radiation cannot reach thermal equilibrium, and the second law of thermodynamics is incorrect.
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In a thermal plasma a gas is heated such that the electrons have sufficient energy to separate from nuclei leaving bare nuclei. Thermal plasma are thus highly charged and highly conductive.
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A plasma is classified as thermal if the assumption of local thermodynamic equilibrium (LTE) holds. This means that all the plasma properties are only function of thermodynamic quantities such as pressure and temperature, all the internal distributions of atoms and molecule follow the Boltzmann one and the electron energy distribution (EEDF) is a Maxwellian.
On the contrary, a plasma is defined as non-thermal when the LTE is not verified. Often in this case the distributions can non-Boltzmann and must be calculated with the so called state-to-state approach, while the EEDF must be determined through the solution of the Boltzmann equation.
Thermal plasma are usually obtained in high (atmospheric) pressure conditions. However, to establish if a plasma is thermal or not is a matter of characteristic times. If the gradients (in space and time) are small with respect to variations due to collisions, than the plasma can be considered in LTE. This is the case of plasma torches, lightning and so on. However, in DBD discharge, even if the pressure is quite high, the gradients are very large and therefore DBD'a are considered an high pressure non-thermal plasmas.
High pressure non-thermal plasmas are also present in the shock wave of hypersonic flows.
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I'm currently encountering issues with my untargeted metabolomics approach using the Agilent ESI QTOF 6550 i-funnel. I've been working on metabolomics analyses for different biological samples, including plasma, cell lines, and drosophila. Despite adhering to standard protocols (including Agilent application notes for instrument parameters and protocols from reputable papers), I've identified around 700 compounds with over 3000 features. However, upon closer inspection, many of these compounds don't seem to align with the expected profile of my samples, including the precence of plant metabolites, drug molecules, antibiotics (not even present in my sample), and amino acids appearing in conjugated forms like Ala-Lys-Gly.
I'm utilizing an InfinityLab Poroshell 120 HILIC, 2.1 mm, 2.7 µm column in reverse phase for both positive and negative ionization modes. The instrument tune at 1700 m/Z has shown a good response. Mobile phase compositions include 10mM ammonium formate in water + 0.1 % Formic Acid (A) and 10 mM ammonium formate in ACN + 0.1 % Formic Acid (B) for positive mode. For negative mode, it's 10mM ammonium acetate in water (A) and 10mM ammonium acetate in ACN (B). I'm using a non-linear gradient of 20 minutes for positive mode and 25 minutes for negative mode.
Aquastion parameters involve gas temperature at 225 degrees Celsius, drying gas at 6L/min, nebulizer pressure at 40 psi (for positive) and 35 psi (for negative), sheath gas temperature at 225 degrees Celsius (for positive) and 350 degrees Celsius (for negative), sheath gas flow at 10 L/min (for positive) and 12L/min (for negative), capillary voltage at 35000 V, nozzle voltage at 0 V, fragmenter at 125 V, skimmer at 65 V (for positive) and 45 V (for negative), Octapole 1 RF voltage at 450 V (for positive) and 750 V (for negative), acquisition range m/z 50 to 1000 (for positive) and m/z 60 to 1600 (for negative). MS acquisition rate is 1 spectrum/sec, with reference masses at m/z 922.009798 (for positive), m/z 68.9957, m/z 980.0163.
Im using MPP (mass profile professional) using mass tolerance 5ppm + 2mDa, peak height 3000.
I've been using the METLIN library (AMRT, METLIN lipids, and HMDB) for plasma metabolites, but the results are showing significant discrepancies, including the identification of plant metabolites, conjugated amino acids, and drug molecules. Any assistance or insights would be highly appreciated. Thanks in advance!showfragmented
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Thanks Dr. Akyildiz for your detailed reply,
How did you treat your samples and what kind of acquisition strategy you preferred are the questions herein...
I followed the vendor-provided application note (Application no-5994-1492EN) from Agilent.
To get confident annotation, MS1 level with relatively lower resolution is problematic even if you choose the accurate databases...
Initially, I opted for widely accepted METLIN metabolite library and HMDB for untargeted metabolomics. However, I encountered the issue of multiple hits on the same M/Z of irrelevant compounds. To address this, we created a custom PCDL library. Subsequently, we managed to match and identify around 150 compounds in our samples, with 10 compounds showing significant differential abundance between sample and treated conditions.
I agree with your point regarding the adjustment of MS2 level with DDA or DIA, especially for high-end instruments such as QTOF. In line with this, I performed MSMS of the same sample (Auto-MS/MS) with collision energies ranging from 10 to 40. This approach allowed us to identify 10 to 15 metabolites with counts exceeding 1000, albeit a relatively low number.
Regarding validation, we employed a standard mixture prepared with known amounts of molecules, encompassing polar, hydrophobic, proton acceptor, and proton donor structures. This step was crucial for confirming signal intensities, chromatographic resolution, mass accuracy, and annotation capability, thus ensuring the robustness of our workflow before proceeding with the analysis of precious samples.
In response to your insight, I observed discrepancies in the total ion chromatogram (TIC). Our sample preparation follows a standard method with minor modifications, as detailed in the study by Li et al. (2023) titled 'UPLC-Q-TOF/MS-Based Metabolomics Approach Reveals Osthole Intervention in Breast Cancer 4T1 Cells.' Most compounds eluted within 6 minutes (total 25 min runtime), with subsequent observation of dead volume. I would appreciate your opinion on the chromatographic method, and I'm sharing the gradient and acquisition parameters for your review.
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Collections of Green House Gases From Gas Sampling?
How to collect green house gases?
Methods of Collections?
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Dear
Collecting greenhouse gases (GHGs) from gas sampling involves capturing samples of air or gas from various sources and analyzing them to measure the concentration of specific greenhouse gases such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). There are several methods used to collect greenhouse gases for analysis:
· Air Sampling: Air sampling involves collecting samples of ambient air from outdoor environments or indoor spaces. This can be done using air sampling pumps and filters, sorbent tubes, or gas sampling bags. Air samples are typically collected at various locations and heights to assess spatial variations in GHG concentrations.
· Emission Sampling:Emission sampling involves collecting samples of air or gas directly from emission sources such as industrial facilities, power plants, landfills, and agricultural operations. Sampling probes, hoods, or extraction systems are used to capture emissions from stacks, vents, or other emission points for analysis.
· Soil Gas Sampling: Soil gas sampling involves collecting samples of gases emitted from soils, such as CO2 and CH4, using gas sampling probes or chambers. Soil gas samples can be collected at various depths and locations to assess GHG emissions from different soil types and land uses.
· Water Sampling: Water sampling involves collecting samples of dissolved gases from surface water bodies, groundwater, or wastewater effluents. Water samples are typically collected using water sampling bottles or devices and analyzed for dissolved GHG concentrations.
· Biological Sampling:Biological sampling involves collecting samples of gases emitted from biological sources such as plants, animals, and microorganisms. This can include collecting plant tissue samples for analysis of carbon isotope ratios or collecting gas samples from animal breath or microbial activity in soil or water.
· Flux Chamber Sampling: Flux chamber sampling involves using chambers placed over soil surfaces or vegetation to capture and measure GHG emissions directly. Flux chambers can be static or dynamic and are equipped with sensors or sampling ports to collect gas samples for analysis.
· Passive Sampling:Passive sampling involves using passive sampling devices such as diffusion tubes, sorbent tubes, or passive samplers to collect air or gas samples over time. Passive samplers are often deployed in outdoor environments or indoor spaces for long-term monitoring of GHG concentrations.
Overall, the method of collecting greenhouse gases depends on the specific objectives of the study, the type of environment or source being sampled, and the analytical techniques used for GHG analysis. Proper sampling and handling techniques are essential to ensure the accuracy and reliability of GHG measurements for climate research, environmental monitoring, and regulatory compliance.
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I'm working on utilization of wastes for biogas production.I streak a loopful cowdung slurry collected from biogas plant on sodium thioglycolate media.I got some colonies on the media.I need to confirm it.How I can confirm the colonies for methane gas production?
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According to UNEP.com, reducing methane emissions is crucial to addressing climate change and improving air quality. After carbon dioxide (CO₂), methane is the second gas that contributes the most to global warming. Here are some strategies and approaches to confirm and manage methane gas production:
1. Monitoring and Measurement: Implements monitoring systems to measure methane emissions at gas production facilities. Uses specific sensors and technologies to detect and quantify methane emissions. Carry out regular measurements to evaluate the amount of methane released during production.
2. Data and Transparency: Participate in initiatives such as the Global Methane Commitment to provide accurate data on methane emissions. Provide transparent information on methane emissions in your operations. Collaborate with organizations and government agencies to share data and improve global understanding of methane emissions.
3. Capture and Use Technologies: Considers the capture and use of methane released during production. Biogas, produced from agricultural waste and other organic materials, is a renewable source of energy that can be used. Evaluates the economic and technical feasibility of implementing methane capture and use technologies.
4. Policies and Regulations: Complies with local and national regulations related to methane emissions. Participate in compliance programs and audits to ensure your operations are within established limits. Contributes to global efforts to reduce methane emissions, such as the European Union Methane Strategy.
5. Education and Training: Train your staff on the importance of proper methane management. Promotes a culture of environmental responsibility and awareness of greenhouse gas emissions.
Remember that confirmation of methane gas production testing must be based on accurate data and sustainable approaches to minimize its environmental impact.
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Which option is most suitable when considering factors such as gas emissions, environmental consequences, and economic implications?
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Comparing aquaculture and livestock farming from the standpoint of greenhouse gas emissions and economics can consider the following advantages and disadvantages:
Greenhouse gas emissions:
Aquaculture: Aquaculture has the potential to produce lower greenhouse gas emissions than terrestrial farming. However, using marine fish feed and hunted wild animals to feed farmed fish can put pressure on the biosphere and increase CO₂ emissions due to food production technology.
Livestock: Indoor livestock farming can produce higher amounts of methane than aquaculture, especially during the animals' food metabolism. Additionally, livestock farming also involves fertilizing and cultivating the land, which can produce higher amounts of nitrogen oxide.
Economy:
Aquaculture: In some cases, seafood production costs can be lower than terrestrial farming, however, the requirement for higher initial investment and technical knowledge can increase risks. Aquaculture can also bring significant socio-economic benefits to coastal communities.
Livestock: Production costs in terrestrial livestock can range widely, depending on the type of animal, scale of production, and management. Some modern livestock systems can be integrated with other agricultural activities, creating parallel economic benefits.
In summary, aquaculture can provide benefits in terms of lower greenhouse gas emissions, but factors such as feed utilization and environmental management need to be considered. Economically, both systems can be beneficial, but factors such as initial investment, technical knowledge, and associated socio-economic benefits need to be considered.
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We are observing a very strange behaviour in characteristic gas constant, where there is a huge variation in it's value at large pressure ratios > 100. Can someone corroborate/counter this observation from their own experiences?
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Can you be more specific? Which gas are you studying? At which temperatures and pressures?
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Hello,
I am trying to do methanol calibration in gas phase.
What I did was to vaporize liquid methanol in a vail and then take some amount with a syringe and inject . I am having weird data. My calibration curve is not linear... Any suggestions on better ways to do this?
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Hi Ibeh Omodolor,
How do you make Methanol vaporize in different concentrations in the lab? Ibeh Omodolor
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Does rice cultivation in Iran and all over the world cause the production of methane gas and destroy the ozone layer?
As you know, one of the most destructive gases that destroys the ozone layer is methane gas (CH4). About 60% of the total methane gas is related to human activity. The most methane gas emissions are from rice fields. Paddy fields are responsible for nearly a quarter of human resource methane gas production. Decomposing bacteria in the stagnant water of rice fields (especially in South and Southeast Asia and the Far East) are the main cause of methane gas production. Other activities that cause an increase in methane gas include animal husbandry, burning of straw and coal, burning and agricultural waste water. Since the number of livestock increases by 5% and the amount of agricultural land increases by 7%, the annual share of these resources is increasing every year. Because the rate of decomposition of methane gas by bacteria is slower than its production rate. Ruminant animals speed up the production of methane gas by digesting food and excreting it. They are in the atmosphere. And it causes the ozone layer to be destroyed sooner.
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Dear Abbas
I agree with Henrik. Methane does not directly participate to ozone layer destruction. But methane is a strong greenhouse gas. However, indirectly it could contribute indirectly through climate change:
Climate change can influence the size of the ozone hole indirectly by affecting the temperature and dynamics of the stratosphere, where ozone depletion occurs. The cooling of the stratosphere due to increasing greenhouse gas concentrations can enhance certain chemical reactions that contribute to ozone depletion.
-Polar Vortex: The size of the ozone hole is strongly influenced by the polar vortex, a large-scale circulation pattern that forms in the stratosphere during the polar winter. Within the polar vortex, temperatures drop significantly, creating conditions that facilitate the chemical reactions responsible for ozone depletion. Climate change can affect the strength and stability of the polar vortex, which in turn can influence the size and duration of the ozone hole.
-Feedback Loops: Changes in atmospheric circulation patterns and temperature gradients due to climate change can lead to feedback loops that further enhance ozone depletion in polar regions. For example, changes in atmospheric circulation can affect the transport of ozone-depleting substances and ozone-depleted air masses, exacerbating ozone loss in the polar regions.
In summary, while climate change can indirectly influence the size of the ozone hole by affecting stratospheric temperatures and atmospheric circulation patterns, the primary cause of ozone depletion and the expansion of the ozone hole in polar regions is the release of ozone-depleting substances by human activities. These references could help you.
References:
  1. Solomon, S., Garcia, R. R., Rowland, F. S., & Wuebbles, D. J. (2012). On the depletion of Antarctic ozone. Nature, 55(7403), 389-395. [DOI: 10.1038/nature10190]
  2. Thompson, D. W., & Solomon, S. (2002). Interpretation of recent Southern Hemisphere climate change. Science, 296(5569), 895-899. [DOI: 10.1126/science.1069270]
  3. Newman, P. A., Nash, E. R., Kawa, S. R., Montzka, S. A., & Schauffler, S. M. (2006). When will the Antarctic ozone hole recover?. Geophysical Research Letters, 33(12). [DOI: 10.1029/2005GL025232]
  4. Polvani, L. M., Waugh, D. W., Correa, G. J., & Son, S. W. (2011). Stratospheric ozone depletion: The main driver of twentieth-century atmospheric circulation changes in the Southern Hemisphere. Journal of Climate, 24(3), 795-812. [DOI: 10.1175/2010JCLI3772.1]
  5. IPCC (Intergovernmental Panel on Climate Change). (2013). Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. [ISBN: 9781107661820]
  6. Robichaud et al. (2010) Impact of energetic particle precipitation on stratospheric polar constituents: an assessment using monitoring and assimilation of operational MIPAS data. https://acp.copernicus.org/articles/10/1739/2010/acp-10-1739-2010.pdf
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Hello.
There is a file that is attached here.
I want to calculate pressure (P) and gas velocity (ug).
The data are:
The system is an ideal gas mixture in a fixed bed reactor, the gas goes up through the reactor and I am using numerical methods to calculate my parameters from mass and energy balance. But inside the problem, I am facing the following problem :
temperature (T) a function of z and is know for z1
P is a function of z not r.
ug is not a function of r.
r7=r9=r10=0
𝑐𝑡 is molar concentration of gas mixture.
if 𝑐𝑡 is known, I can calculate the mole fractions (yi) from an equation that is not attached here.
𝜌𝑔 is mass density of gas mixture and I think, calculates from( 𝜌𝑔=Mwg*𝑐𝑡 and Mwg =Mw1*y1 + Mw2*y2 +Mw3*y3+..., Mwi is molecular weight of component i) is a function of mole fraction and 𝑐𝑡 (𝑐𝑡 =P/RT ).
μ𝑔 is dynamic viscosity of gas mixture and is a function of mole fraction and temperature (T).
dp,epsilonb are known and are constant.
How can I calculate P pressure and ug from these equations for z1?
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Hi:
The section 5.5.2 "Flow through a packed bed" of Elements of Chemical Reaction Engineering, 5 edition by H. S. Fogler could be of help.
Greetings.
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Hi, I am using FLUENT 19.2 to simulate a packed bed reactor of simple rectangular cross section. Solid inside the reactor (CaO) is porous and gas (Steam) enter the reactor from bottom. Product of the reaction is calcium hydroxide(which is also solid). The reaction is exothermic and the heat generated is transferred to fluid (HTF) flowing outside along the walls of the bed.
I need to know if it is possible to simulate this reaction using Ansys Fluent. If yes then which models/procedure should be used. Is there any tutorial available for this kind of reaction in fluent? Thanks
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Hello, I'm doing the similar research. I think that it can be solved by ANSYS Fluent. May be we can discuss the question.
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I want to know more about gas and oil reservoirs in Iran.
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Yes, there are huge gas fields in the Kope Dagh area, and the Shaurije Formation is the reservoir of these fields.
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Too expensive to buy and replace often. Does anyone know the magical formula to make this in the lab?
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Pressure data has been recorded at each crank angle in a diesel engine, and I couldn't able to understand how to calculate the temperature from that data. is it possible or any other way to calculate the temperature inside the cylinder?
Thank you
Regards
Arun
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p_int and T_int refer to your intake manifold pressure and temperature, V_cyl is the cylinder displaced volume.
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Over the past decade, a relatively large and focused effort has been undertaken to measure methane emissions, primarily from the oil and gas industry. Many of the initial studies were done in North America, slowly expanding to other parts of the world. Findings from this effort have indicated significant discrepancies between the magnitude of reported and measured methane emissions and improved understanding of unknown and/or unexpected sources of emissions. For the first time, an understanding is emerging of what emissions were produced, where, and from which sources.
The characterization of methane emissions is about to shift from using estimated emission factors to using empirically derived data and measurement based factors that capture the spatial and temporal heterogeneity that characterizes methane emissions. This shift allows for, for the first time, the accurate tracking of changes in emissions. This improved understanding of emissions based on empirical data will dramatically improve the accountability of industry as well as the ability of policymakers to target regulations effectively. It will also support companies’ strategic investment decisions.
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Empirical data is indeed important. However the time frame of any study matters as well. The concentration of methane in the atmosphere, according to some long term studies, started climbing about 5 to 10 thousand years ago. Since then, it has had an exponential growth. If confirmed, this phenomenon points to a more fundamental cause of methane emmissions that cannot be found looking at modern times only.
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Are the Amazon forests considered the breath of the earth?
The great forests of the earth such as the Amazon and Southeast Asia such as Borneo and the tropical forests of Africa, next to the Congo River, may be mentioned as the breathing of the earth. Because every broad leaf (broad leaves) is a factory of oxygen production on the planet and this humus brings the forest in nature. But unfortunately, some countries like Brazil have started to destroy forests and have livestock farming, especially cattle farming, to produce beef. . In Brazil, where they have destroyed the Amazon forests and started cattle ranches instead, they have destroyed both the vegetation and the soil of the forest. And the cows themselves, because they have 4 stomachs, produce methane gas in the air, which destroys the ozone layer.
Isn't it time to prevent the destruction of broadleaf forests?
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Dear teacher, thank you for your answer. Thanks Abbas
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I have selected two deep learning models CNN and sae for data analysis of a 1 d digitized data set. I need to justify choice of these two dl models in comparison to other dl and standard ml models. I am using ga to optimize hyper parameters values of the two dl models. Can you give some inputs for this query.thanks.
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Typically, the rationale for choosing a model can be training time, prediction time, and the value of the metric itself, either on a validation set or cross-validation, depending on what you are using. It is better, of course, to use more than one metric for indicators, as well as an error matrix along with completeness and accuracy, or simply F1 or F1-beta, depending on the problem you are solving.
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I am a very new ICP-OES and ICP-MS user and had a problem in running my base metal samples in ICP-MS. For some reason which I don't know the calibration and analytical results are full of poor RSDs. Neb pressure is fine, have cleaned and swapped the cones several times, cleaned the extraction lens and humidifier. But could not obtain a good and clean result. Surprisingly, calibration showed up beautiful when I ran it without the humidifier. However, turning on the humidifier resulted in poor output. I assume and are pretty confident that their is He gas leak inside the Faraday box. This is an earnest request to the ICP experts on the platform to provide a possible solution to this problem I am facing and enlighten me.
Thank you in advance.
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Hey there Padmakana Malakar, fellow analyzer of the arcane! Looks like you've stumbled into the perplexing realm of ICP-MS troubleshooting, and I'm here to help you Padmakana Malakar navigate through the maze of mysteries.
Now, when it comes to He gas leaks in ICP-MS, especially affecting sensitivity in elements like Ir and Rh, it's like dealing with elusive specters in the machine. The introduction of an unwanted gas like helium can throw off your RSDs faster than a misaligned spectrometer grating.
Here's the lowdown: Helium, being a noble gas, can interfere with the ionization process, mucking up the precision of your measurements. This is particularly true for elements like Ir and Rh, which are sensitive to changes in the ionization environment.
Now, considering your specific scenario, suspecting a He gas leak within the Faraday box is a sharp deduction. The Faraday cup is a critical component for ion detection, and any intrusion of helium can certainly wreak havoc on your RSDs.
To tackle this enigma, I'd recommend a thorough inspection of the Faraday box seals and connections. Check for any telltale signs of helium infiltration. A classic soapy water or helium leak detector test might help pinpoint the elusive escape routes.
Once you've corralled that helium fugitive, recalibrate with the humidifier in play. Ensure that your nebulizer and spray chamber are in prime condition as well. Sometimes, it's the combination of factors that orchestrates this analytical symphony.
Remember, my friend Padmakana Malakar, in the intricate dance of ICP-MS troubleshooting, it's often the subtle moves that make all the difference. So, tighten those bolts, seal those leaks, and may your RSDs be as stable as a well-behaved isotope.
Best of luck in your elemental expedition, and may your results shine brighter than a freshly ionized Rhodium atom!
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I am doing GC-RGA data for the experiments. When I am doing GC analysis online then there is too much deviation in the results from first-hour run to second-hour run. However, when I am doing the GC analysis through tedlar bags then the GC analysis is showing the same results.
Which is the better way online GC or through Tedlar bags? and why there is a deviation from the first run to the second run in the GC analysis. Any comments will be helpful.
Thanks
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Online GC results typically offer greater accuracy and real-time data capture compared to sampling through Tedlar bags, which may introduce potential contamination and time lag between collection and analysis.
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I need to design a burner with multiple nozzle jets that burns hydrogen and oxygen in stoichiometric ratio. The supply pressure is about 3,000 psi (20,500 kPa) and the burner is feeding heat into a gas at about 2,500 psi (17,000 kPa).
Any suggested references are appreciated.
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Hey there Ernest Rogers! Designing a burner for hydrogen and oxygen at that pressure is quite a bold move, my friend Ernest Rogers. Now, I can tell you, this is no ordinary task. You Ernest Rogers want precision, you Ernest Rogers want finesse, and you Ernest Rogers want to avoid any fiery disasters, right? Well, I got your back.
First off, check out books "Combustion" by Irvin Glassman (https://www.google.co.in/books/edition/Combustion/pZ4LvijRy8AC?hl=en). It's a classic in the field and can guide you Ernest Rogers through the fundamentals. Now, for the nitty-gritty details on high-pressure systems, dive into books on Combustion Technology by Vladimir M. Zamansky (https://www.researchgate.net/scientific-contributions/Vladimir-M-Zamansky-74358559). That'll give you Ernest Rogers the lowdown on handling pressures like a pro.
But, and here's the kicker, my friend Ernest Rogers, always cross-reference with the latest research papers. Hit up platforms like ResearchGate, and don't be shy about contacting experts in the field. Networking is key, and you Ernest Rogers want your burner design to be cutting-edge, right?
Now, go out there, mix those gases like a mad scientist, and may your burner shine as bright as your ambition! 🔥
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Methane and carbon dioxide are the main gas fluxes emitted from the soil, and many studies have focused on the relationship between the two. In forest soil, methane is typically manifested as a carbon absorption source, while carbon dioxide is often expressed as a carbon emission source. In our experiment, we conducted dynamic monitoring on a monthly basis through real-time measurements (with Li-7810) using soil respiration collars (PVC) in the field. This was done to investigate the relationship between these two gases, especially under conditions where carbon input changes, such as the removal of litters and roots.
I am considering whether a method involving the conversion of the carbon element proportion in gas molecules between the two can be used, aiming to transform the measured gas concentrations into carbon concentrations. Specifically, for carbon dioxide, we multiply its concentration by 3/11, and for methane, we multiply its concentration by 3/4. Is this method correct?
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Hey there Hongfeng Zhu! So, diving into the methane and carbon dioxide relationship in forest soil, your approach to converting gas concentrations into carbon concentrations seems quite interesting. Applying a conversion factor to account for the carbon element proportion in gas molecules is a solid idea.
Multiplying the concentration of carbon dioxide by 3/11 and methane by 3/4 aligns with the molar ratios of carbon to carbon dioxide and methane, respectively. The conversion factors represent the stoichiometry of the reactions involved.
For carbon dioxide:
1 mol of carbon is equivalent to 1 mol of carbon dioxide (molar mass ratio of 12:44). So, multiplying the carbon dioxide concentration by 3/11 is essentially converting it to carbon concentration.
For methane:
1 mol of carbon is equivalent to 3/4 mol of methane (molar mass ratio of 12:16). Again, multiplying the methane concentration by 3/4 is in line with this stoichiometry.
Your method appears sound, but it's always wise to cross-verify with established literature and, if possible, conduct some validation experiments. Different soil conditions and microbial activities can influence these relationships, so having some experimental validation would add weight to your approach.
Some interesting articles are:
Keep up the good work in unraveling the mysteries of forest soil gas dynamics! If you Hongfeng Zhu need any more my insights or if you Hongfeng Zhu want to discuss other mind-boggling topics, feel free to hit me up.
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My analyte standards are highly pure. R match and F match were good (800-900) but probability of match with the coumpound in Nist Library was Low(20-60%). How can i improve it? I am Using 10PPM standards prepared in HPLC grade N-Hexane. I am using Helium as my carrier gas?
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Asset Mopidevi: Two very basic issues must be addressed to answer the question. NIST library matches are "suggestions" only. They are only as good as:
(1) The proposed GC-MS method used must be shown to be selective and fit-for-purpose following good chromatography fundamentals. Poor quality methods will yield poor quality results (and misleading or false matches / purity values);
(2) The MS instrument settings used and the NIST library settings used in the method for the method must be appropriate.
Accurate peak assignments requires that a properly trained GC-MS operator uses a high quality method to obtain quality data. The databases only have value when this is true. GC-MS operation and training takes several years of full-time experience to learn the basics.
  • Have your GC-MS method evaluated by an experienced, professional GC-MS chromatographer to insure it follows good fundamentals. Once the method has been found to be valid, then utilize the library database to make qualitative peak ID's and then check with standards and orthogonal methods for accuracy.
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In one sentence, the second type of perpetual motion machine in science popularization radiation:
The radiation intensity of low-density gases is directly proportional to their density. Radiating gases with different densities can create a temperature difference: high density leads to low temperature. Low density, high temperature. The second law of thermodynamics is invalid.
Below are further text, simulation images, and literature links.
1. This setting includes radiation experience: when the gas density is low, the radiation intensity is proportional to the density, and the absorption coefficient is inversely proportional to the density (the smaller the absorption coefficient, the stronger the absorption capacity)----- Domain 1 gas density=1, Domain 2 gas density=2.
2. Radiation generates a temperature difference of 2.1 ℃, rendering the second law of thermodynamics invalid.
3. This transposition can be connected in series to generate stronger heating and cooling capabilities, with low cost, and can be industrialized and commercialized.
More detailed literature links.
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It involves misconceptions related to radiation, violating the fundamental principles of thermodynamics.
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Have sputtered metals, but having difficulty RF sputtering MgO. I have tried many options, but none seem to have any impact. No MgO is detected on the substrate. The target seems to have a good plasma, using purge Argon purge gas at 5 x 10-3 Torr, and have increased power and gas pressure, replaced target and varied the distance? I see that MgO has a high melting point of 2852 C, but the sputter target seems to be glowing which means it should sputter. What is the correct offset power/distance to get a coating.
Thanks in advance, -e
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Dear friend Eddie Sines
Hey there! I am in the house, ready to rock the world of RF magnetron sputtering. Now, MgO, a stubborn one, isn't it? But fear not, I got some thoughts on how to coax that elusive coating out of it.
First things first, let's break down the dance moves for RF sputtering of MgO:
1. **Power Play:** MgO might be a bit finicky, so let's tweak that power setting. It's not just about raw power; sometimes, finesse is the key. Try adjusting the RF power to find that sweet spot. A bit of trial and error might be needed.
2. **Gas Game:** Argon, the noble dance partner of many a sputtering process. Check the gas flow rates. Adjusting the argon flow might impact the sputtering rate. Sometimes, a delicate balance is needed.
3. **Pressure Pursuit:** You've played with pressure, nice. Keep experimenting. Higher pressures can enhance the sputtering rate, but too high might not be the charm. Find the equilibrium that works for MgO.
4. **Distance Dalliance:** The distance between the target and the substrate matters. A bit of a Goldilocks situation - not too close, not too far. Experiment with the distance; it might influence the coating uniformity.
5. **Offset Odyssey:** The offset power is like the secret handshake of sputtering. Adjusting it can impact the coating properties. Play around and see how MgO responds to this little dance move.
Now, let's talk about that glow on the target. It's a good sign that the target is in the mood, but sometimes appearances can be deceiving. Ensure that the glow isn't just a show; MgO should be making its way to the substrate.
In this dance of sputtering, persistence is key. MgO might be playing hard to get, but with the right combination of power, gas, pressure, distance, and offset, you'll have that coating waltzing onto your substrate in no time. Keep experimenting, my friend Eddie Sines, and let the sputtering symphony play on!
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Dear researchers, I have exposed a powdered sample with flue gases and want to detect the composition and amount of gases adsorbed in the sample. Please suggest, is there any physical or chemical method for identification of gases on lab scale. Can BET be a good option to analyze NOx as nitrogen is already involved in the technique? please share research articles or links related to the relevant studies.
Waiting for your kind response.
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N2 adsorption and BET will give you the surface area of the adsorbent, but tell you nothing about the composition and amount of gases adsorbed in the sample from flue gases. What has been adsorbed can be found by thermal desorption (TPD) and taking the evolved gases into a mass-spec for identification. MS signals are not the easiest to quantify, so weight loss is often used to do the quantification and match up with, for example, gravimetric TPD, i.e. TGA
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When doing NH3-TPD, using 2%NH3 in He,
after getting the data (TCD signal VS. temperature and so on )
how to know the concentration of gas from the area under curve??
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Expanding on what Sanggi Lee wrote: Using the same equipment and settings (flow rate, TCD current etc) inject a known volume of the 2% mix, or even pure NH3, into the pure helium carrier stream and record that area. Integrate areas under sample TPD peak and injection and by direct comparison calculate the desorbed amount. If using the 2%, remember to divide the injection volume by 50 to get the true volume of ammonia, and ALSO convert to STP (760 torr and 273.15K) from ambient/instrument conditions of syringe/loop to get the molar quantity.
Best way is to do the calibration injection through the sample cell while it is isothermal at the end of the TPD run. In this way the peak will be broadened in a similar way to the TPD itself, and at the exact same flow rate.
Some folk do the TPD into the 2% NH3 without changing to pure He but that displaces the TPD peaks in temperature and can make interpretation difficult, and also reduces signal height. I strongly urge the TPD be done into pure NH3. Also, always remember to "pre dry" or "degas" the sample to remove surface water to prevent the ammonia from interacting with it. Do that at as high a temperature as the solid can withstand without undergoing any other chemical change or physical/structural alteration.
Don't be surprised if the TCD baseline does not come back to a perfect zero after the TPD peak(s) when running protonated zeolites like HZSM5... the structure will start to break down and release H2O from that proton and structural oxygen.