scholarly journals Diagnostics of Nitrogen-methane Atmospheric Glow Discharge Used for a Mimic of Prebiotic Atmosphere

2017 ◽  
Vol 4 (1) ◽  
pp. 83-86
Author(s):  
V. Mazánková ◽  
L. Töröková ◽  
D. Trunec ◽  
F. Krčma ◽  
S. Matejčík ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Previous Investigation ◽  
Chemical Processes ◽  
Planetary Atmosphere ◽  
Gas Mixture ◽  
Prebiotic Atmosphere ◽  
Infra Red ◽  
Complex Chemistry ◽  
Life On Earth

The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Titan. The complex chemistry revealed in such atmospheres leading to the synthesis of bigger molecules is providing new insights into our understanding of how life on Earth developed. This work extends our previous investigation of nitrogen-methane (N<sub>2</sub>-CH<sub>4</sub>) atmospheric glow discharge for simulation chemical processes in prebiotic atmospheres. In presented experiments 2 % of water vapor were addet to nitrogen-methane gas mixture. Exhaust products of discharge in this gas mixture were in-situ analysed by Fourier Transform Infra Red spectroscopy (FTIR). The major products identified in spectra were: hydrogen cyanide, acetylene and acetonitrile.

scholarly journals The Influence of CO2 Admixtures on Process in Titan's Atmospheric Chemistry

2016 ◽  
Vol 3 (3) ◽  
pp. 163-167
Author(s):  
L. Torokova ◽  
V. Mazankova ◽  
N. J. Mason ◽  
F. Krcma ◽  
G. Morgan ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Atmospheric Chemistry ◽  
Hydrogen Cyanide ◽  
Planetary Atmosphere ◽  
Atmospheric Processes ◽  
Chemical Complexity ◽  
Discharge Gas ◽  
Complex Chemistry ◽  
Life On Earth

The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Titan. The complex chemistry revealed in such atmospheres leading to the synthesis of bigger molecules is providing new insights into our understanding of how life on Earth developed. In our experiments Titan's atmosphere is simulated in a glow discharge formed from a mixture of N<sub>2</sub>:CH<sub>4</sub>:CO<sub>2</sub> gas. Samples of the discharge gas were analysed by GC-MS and FTIR. The major products identified in spectra were: hydrogen cyanide, acetylene and acetonitrile. The same compounds were detected in the FTIR: hydrogen cyanide, acetylene and ammonia. Whilst many of these compounds have been predicted and/or observed in the Titan atmosphere, the present plasma experiments provide evidence of both the chemical complexity of Titan atmospheric processes and the mechanisms by which larger species grow prior to form the dust that should cover much of the Titan's surface.

scholarly journals GC-MS and GC-FID Analysis of Products from Glow Discharge in N2 + CH4 Mixture

2018 ◽  
Vol 5 (3) ◽  
pp. 103-106
Author(s):  
V. Mazankova ◽  
I. Manduchová ◽  
F. Krcma ◽  
L. Prokes ◽  
D. Trunec
Keyword(s):  
Gas Chromatography ◽  
Glow Discharge ◽  
Hydrogen Cyanide ◽  
Previous Investigation ◽  
Chemical Processes ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Surface Areas ◽  
Different Shapes

This work extends our previous investigation of nitrogen-methane atmospheric glow discharge for the simulation of chemical processes in prebiotic atmospheres. Also reactions on surfaces of solid state bodies can be important. So in presented experiments the electrodes with different shapes and different surface areas were used. Exhaust products of discharge in this gas mixture were analyzed by Gas Chromatography - Mass Spectrometry (GC-MS) and Gas Chromatography - Flame Ionization Detector (GC-FID). The major products identified in chromatograms were hydrogen cyanide and acetylene.

scholarly journals Influence of Casting Solvents on CO2/CH4 Separation Using Polysulfone Membranes

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 286
Author(s):  
Roba M. Almuhtaseb ◽  
Ahmed Awadallah-F ◽  
Shaheen A. Al-Muhtaseb ◽  
Majeda Khraisheh
Keyword(s):  
High Efficiency ◽  
In Situ Synthesis ◽  
Separation Process ◽  
Polymeric Membranes ◽  
Gas Mixture ◽  
Manufacturing Cost ◽  
Binary Gas Mixture ◽  
Maximum Permeability ◽  
Polysulfone Membranes

Polysulfone membranes exhibit resistance to high temperature with low manufacturing cost and high efficiency in the separation process. The composition of gases is an important step that estimates the efficiency of separation in membranes. As membrane types are currently becoming in demand for CO2/CH4 segregation, polysulfone will be an advantageous alternative to have in further studies. Therefore, research is undertaken in this study to evaluate two solvents: chloroform (CF) and tetrahydrofuran (THF). These solvents are tested for casting polymeric membranes from polysulfone (PSF) to separate every single component from a binary gas mixture of CO2/CH4. In addition, the effect of gas pressure was conducted from 1 to 10 bar on the behavior of the permeability and selectivity. The results refer to the fact that the maximum permeability of CO2 and CH4 for THF is 62.32 and 2.06 barrer at 1 and 2 bars, respectively. Further, the maximum permeability of CF is 57.59 and 2.12 barrer at 1 and 2 bars, respectively. The outcome selectivity values are 48 and 36 for THF and CF at 1 bar, accordingly. Furthermore, the study declares that with the increase in pressure, the permeability and selectivity values drop for CF and THF. The performance for polysulfone (PSF) membrane that is manufactured with THF is superior to that of CF relative to the Robeson upper bound. Therefore, through the results, it can be deduced that the solvent during in-situ synthesis has a significant influence on the gas separation of a binary mixture of CO2/CH4.

Grand challenges in the nitrogen cycle

2021 ◽  
Author(s):  
Nicolai Lehnert ◽  
Bradley W. Musselman ◽  
Lance C. Seefeldt
Keyword(s):  
Nitrogen Cycle ◽  
Chemical Processes ◽  
Current Understanding ◽  
Anthropogenic Effects ◽  
Grand Challenges ◽  
Complex Chemistry

In this Viewpoint, we address limitations within our current understanding of the complex chemistry of the enzymes in the Nitrogen Cycle. Understanding of these chemical processes plays a key role in limiting anthropogenic effects on our environment.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

A Comparison of Mos Devices with In-Situ Boron Doped Polysilicon and Poly Sige Gates Deposited in an Rtcvd System Using S12H6 and B2H6 Gas Mixture

1998 ◽  
Vol 525 ◽  
Author(s):  
M. R. Mirabedini ◽  
V. Z-Q Li ◽  
A. R. Acker ◽  
R. T. Kuehn ◽  
D. Venables ◽  
...  
Keyword(s):  
Flat Band ◽  
Gas Mixture ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Boron Doped ◽  
Depletion Effect ◽  
Polysilicon Films ◽  
Sims Analysis ◽  
Boron Penetration

ABSTRACTIn this work, in-situ doped polysilicon and poly-SiGe films have been used as the gate material for the fabrication of MOS devices to evaluate their respective performances. These films were deposited in an RTCVD system using a Si2H6 and GeH4 gas mixture. MOS capacitors with 45 Å thick gate oxides and polysilicon/poly-SiGe gates were subjected to different anneals to study boron penetration. SIMS analysis and flat band voltage measurements showed much lower boron penetration for devices with poly-SiGe gates than for devices with polysilicon gates. In addition, C-V measurements showed no poly depletion effects for poly-SiGe gates while polysilicon gates had a depletion effect of about 8%. A comparison of resistivities of these films showed a low resistivity of 1 mΩ-cm for poly-SiGe films versus 3 mΩ-cm for polysilicon films after an anneal at 950 °C for 30 seconds.

In-situ quantification of NO synthesis in a warm air glow discharge by WMS-based Mid-IR QCL absorption spectroscopy

2022 ◽  
Author(s):  
Chuanqi Wang ◽  
Junjie Qiao ◽  
Yijia Song ◽  
Qi Yang ◽  
Dazhi Wang ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Glow Discharge ◽  
Absorption Spectroscopy ◽  
Energy Cost ◽  
High Energy ◽  
Cathode Region ◽  
Synthesis Rate ◽  
No Production ◽  
Airflow Rate

Abstract Nitric oxide (NO) is one of the most crucial products in the plasma-based nitrogen fixation process. In this work, in-situ measurements were performed for quantifying the NO synthesis spatially in a warm air glow discharge, through the method of Mid-infrared quantum cascade laser absorption spectroscopy (QCL-AS). Two ro-vibrational transitions at 1900.076 cm-1 and 1900.517 cm-1 of the ground-state NO(X) were probed sensitively by the help of the wavelength modulation spectroscopy (WMS) approach to increase the signal/noise (S/N) level. The results show a decline trend of NO synthesis rate along the discharge channel from the cathode to the anode. However, from the point of energy efficiency, the cathode region is of significantly low energy efficiency of NO production. Severe disproportionality was found for the high energy consumption but low NO production in the region of cathode area, compared to that in the positive column zone. Further analysis demonstrates the high energy cost of NO production in the cathode region, is ascribed to the extremely high reduced electric field E/N therein not selectively preferable for the processes of vibrational excitation or dissociation of N2 and O2 molecules. This drags down the overall energy efficiency of NO synthesis by this typical warm air glow discharge, particularly for the ones with short electrode gaps. Limitations of further improving the energy cost of NO synthesis by variations of the discharge operation conditions, such as discharge current or airflow rate, imply other effective manners able to tune the energy delivery selectively to the NO formation process, are sorely needed.

Low-Temperature Epitaxial Growth of IN-Situ HeavilY B-Doped Si1-xGex, Films Using Ultraclean LPCVD

1998 ◽  
Vol 533 ◽  
Author(s):  
A. Morrya ◽  
M. Sakuraba ◽  
T. Matsuura ◽  
J. Murota ◽  
I. Kawashima ◽  
...  
Keyword(s):  
Low Temperature ◽  
Partial Pressure ◽  
Epitaxial Growth ◽  
Lattice Constant ◽  
Deposition Rate ◽  
Epitaxial Films ◽  
Similar Degree ◽  
Gas Mixture ◽  
Heavy Doping

AbstractIn-situ heavy doping of B into Si1-xGex epitaxial films on the Si(100) substrate have been investigated at 550°C in a SiH4(6.0Pa)-GeH4(0.1−6.0Pa)-B2H6(1.25 ×10−5−3.75 × 10−2Pa)-H2(17–24Pa) gas mixture by using an ultraclean hot-wall low-pressure CVD system. The deposition rate increased with increasing GeH4 partial pressure, and it decreased with increasing B2H6 partial pressure only at the higher GeH4 partial pressure. As the B2H6 partial pressure increased, the Ge fraction scarcely changed although the lattice constant of the film decreased. These characteristics can be explained by the suppression of both the SiH4 and GeH4 adsorption/reactions in a similar degree due to B2H6 adsorption on the Si-Ge and/or Ge-Ge bond sites. The B concentration in the film increased proportionally up to 1022cm3 with increasing B2H6 partial pressure.

scholarly journals Biphenyl Hydrogenation with Syngas for Hydrogen Purification and Transportation: Performance of Dispersed Catalytic Systems Based on Transition Metal Sulfides

2021 ◽  
Vol 61 (10) ◽  
pp. 1131-1137
Author(s):  
I. G. Baigildin ◽  
E. A. Karakhanov ◽  
A. L. Maximov ◽  
A. V. Vutolkina
Keyword(s):  
Hydrogen Uptake ◽  
Gas Mixture ◽  
Hydrogen Purification ◽  
Catalytic Systems ◽  
Dispersed Catalysts ◽  
Substrate Conversion ◽  
Hydrogen Carrier ◽  
Shift Reaction ◽  
Water Gas

Abstract The feasibility of biphenyl hydrogenation with syngas for hydrogen purification and binding with the aim of its transportation was demonstrated. Specific features of the hydrogenation of biphenyl as a promising organic hydrogen carrier using unsupported Ni–Mo sulfide catalysts were studied. In particular, the influence of temperature, reaction time, presence of water in the system, and Н2/СО gas mixture composition on the substrate conversion and selectivity with respect to products was examined. The highest conversion and the maximal hydrogen uptake are reached at 380°С in 6–8 h. The dispersed catalysts are active in biphenyl hydrogenation at the CO concentration in the Н2/СО gas mixture of up to 50 vol %, and H2O can act in this case as an in situ hydrogen source owing to the occurrence of the water-gas shift reaction.

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