Pure Nitrogen Research Articles

Compressibility of Abnormal Pressure Gas Reservoirs and Its Effect on Reserves.

The compressibility of abnormal pressure gas reservoirs is hard to test, and the interpretation is confusing, leading to many misunderstandings in the current understanding of abnormal pressure gas reservoirs. In this research, a high-pressure experimental system was designed, and a series of high-pressure compressibility tests of pure water, nitrogen, and rocks under different water saturations were carried out. Then, the effective compressibility of gas reservoirs was calculated; the effect of water saturation on abnormal pressure gas reservoirs and the dynamic prediction was studied. The results show that the compressibilities of water and rock are effectively constant values over the range examined, while the compressibility of gas decreases exponentially with the increase in pressure. The effective compressibility of the stratum increases with the rise of water saturation. The theory of stress and strain of rock mechanics also shows that the rock compressibility is determined by Young’s modulus, Poisson’s ratio, and porosity and has no connection with the formation pressure. With the increase in water saturation, the swelling degree of the production indicator curve of the simulation experiment becomes larger and larger. After introducing the effective compressibility of the stratum into the gas–water material balance equation, the gas reserves predicted by the revised production indicator curve are the same as the original reserves. The research results have important guiding significance for the efficient development of gas reservoirs.

Experimental Study of the Effect of Precursor Composition on the Microstructure of Gallium Nitride Thin Films Grown by the MOCVD Process

Abstract Chemical vapor deposition (CVD) is a widely used manufacturing process for obtaining thin films of materials like silicon, silicon carbide, graphene, and gallium nitride that are employed in the fabrication of electronic and optical devices. Gallium nitride (GaN) thin films are attractive materials for manufacturing optoelectronic device applications due to their wide band gap and superb optoelectronic performance. The reliability and durability of the devices depend on the quality of the thin films. The metal-organic chemical vapor deposition (MOCVD) process, which uses compounds that contain metals and organic ligands as precursors in a CVD reactor, is a common technique used to fabricate high-quality GaN thin films. The deposition rate and uniformity of thin films are critical to a successful and useful process. These are determined by the thermal transport processes and chemical reactions occurring in the reactor, and are manipulated by controlling the operating conditions and the reactor geometrical configuration. In this study, the epitaxial growth of GaN thin films on sapphire (Al2O3) substrates is carried out in two commercial MOCVD systems: a vertical rotating disk MOCVD reactor and a close-coupled showerhead MOCVD reactor. The surface morphology and crystal quality of GaN thin films have been examined using atomic force microscopy (AFM) and scanning electron microscope (SEM). This paper focuses on the composition of the precursor and the carrier gases since earlier studies have shown the importance of precursor composition. The results show that the flow rate of trimethylgallium (TMG), which is the main ingredient in the process, has a significant effect on the deposition rate and uniformity of the films. Also, the carrier gas plays an important role in deposition rate and uniformity. Using hydrogen as a carrier gas enhances the quality of the thin film but a lower deposition rate occurs on the wafer surface. On the other hand, a high flow rate of pure nitrogen gas improves the growth rate of the film. However, it decreases the uniformity of the film and promotes carbon contamination on the wafer surface. Thus, the use of an appropriate mixture of hydrogen and nitrogen as the carrier gas can improve the deposition rate and quality of GaN thin films.

Determination of The Effect of Different Plant Densities and Nitrogen Doses on Agronomical Traits of Sweet Corn (Zea mays saccharata Sturt.) In Conditions of The Northern-East Transitional Region Conditions of Turkey

This study was carried out to determine the differences in yield and quality characteristics of different plant density and nitrogen doses in sweet corn (Zea mays L. saccharata Sturt) during 2017 and 2018 years. This research was conducted according to a split-plot design with three replications in the Bingol University Faculty of Agriculture Application and Research Farm. Vega sweet corn hybrid was measured with three intra-row spacing (15, 20, 25 cm) and five pure nitrogen doses (0, 80, 160, 240, 320 N kg ha-1) were grown. In the study, the increasing nitrogen dose showed a significant rise in number of ears per plant , number of kernels per ear, relative chlorophyll content, water-soluble solids content, and fresh ear yield . It was determined that plant density positievly effected fresh ear yield; but the number of kernels per ear, the number of ears per plant, relative chlorophyll content were decreased. The highest fresh ear yield was determined D15 (13106 kg ha-1) in terms of plant density and N3 (15905 kg ha-1) in terms of nitrogen dose according to the combined experiment years analysis. Considering the average of years, 240 N kg ha-1 (N3) and approximately 100000 plants per hectare (S15) for optimum the fresh ear yield fertilizer application are recommended.

Effects of a negative corona discharge on subsequent positive streamers

Positive streamers can be affected significantly by preceding discharges such as earlier streamers or a corona discharge. In this paper, we primarily discuss the effect of such a corona discharge on subsequent positive streamers with different intervals between them (0/500/990 ms) in air and pure nitrogen at 80 mbar with a repetition frequency of 1 Hz. We found that in air, when the interval time is 500 or 990 ms, a preceding discharge leads to shorter and weaker streamers or even prevents streamer inception altogether. This is likely due to negative ions which have converted to species that are harder to detach. The weaker streamers are also caused by more stable inception clouds which branch out later. When a corona discharge immediately precedes a streamer discharge in air, the streamers become longer, brighter while some branches develop from the side of the electrode instead of its tip. These effects are likely all related to plasma shielding caused by the corona discharge. In nitrogen, inception is primarily caused by electrons instead of negative ions. When the interval time is 500 or 990 ms in this gas, there is nearly no difference between streamers with and without a preceding corona discharge, because the inception time in nitrogen is the formative time that is not sensitive to the initial electron density. For near-zero intervals between corona and streamer discharges in nitrogen, streamers become smoother and thicker which can be attributed to a higher background ionization left by the corona discharge.

Understanding the impurity gettering effect of polysilicon/oxide passivating contact structures through experiment and simulation

Polysilicon/oxide (poly-Si/SiOx) passivating contacts are a promising technology for the next-generation of high-efficiency silicon solar cells. The structure can be realised by a range of fabrication techniques, which can induce very different impurity gettering effects during the formation process. Understanding the different gettering effects will enable tailored solutions to optimise the gettering efficiency in device fabrication. This paper demonstrates a method to separately quantify the impact of each component on the overall gettering effect of the poly-Si/SiOx passivating contact structures. These components consist of the heavily doped poly-Si layer, in terms of its gettering strength; the SiOx interlayer, regarding its potential blocking effect for slowing down the diffusion of impurities; and the dopant in-diffused surface regions of the silicon wafer bulk directly below the SiOx interlayer, which may have a small additional gettering effect due to heavy doping. Phosphorus in-situ doped poly-Si layers from plasma-enhanced chemical vapour deposition (PECVD), coupled with SiOx interlayers from different growth techniques, were used to demonstrate the method. The experimental and simulation results confirm that the heavily doped poly-Si layer acts as the main gettering sink and the presence of different SiOx interlayers determines the overall gettering rate. For the ultrathin SiOx interlayers studied in this work, which have a similar thickness but different stoichiometry, a standard thermally grown SiOx demonstrates the strongest blocking effect, followed by a chemically grown SiOx from hot nitric acid, and a thermal SiOx of a reduced stoichiometry (grown in a pure nitrogen ambient) demonstrates practically no blocking effect.

Effects of Biogas Slurry Combined With Chemical Fertilizer on Soil Bacterial and Fungal Community Composition in a Paddy Field.

The application of biogas slurry and chemical fertilizer in paddy fields can be a practical method to reduce the environmental risk and utilize the nutrients of biogas slurry. The responses of bacterial and fungal communities to the application of biogas slurry and chemical fertilizer are important reflections of the quality of the ecological environment. In this study, based on a 3-year field experiment with different ratios of biogas slurry and chemical fertilizer (applying the same pure nitrogen amount), the Illumina MiSeq platform was used to investigate the bacterial and fungal community diversity and composition in paddy soil. Our results revealed that compared with the observations under regular chemical fertilization, on the basis of stable paddy yield, the application of biogas slurry combined with chemical fertilizer significantly enhanced the soil nutrient availability and bacterial community diversity and reduced the fungal community diversity. Dissolved organic carbon (DOC), DOC/SOC (soil organic carbon), available nitrogen (AN) and available phosphorus (AP) were positively correlated with the bacterial community diversity, but no soil property was significantly associated with the fungal community. The bacterial community was primarily driven by the application of biogas slurry combined with chemical fertilizer (40.78%), while the fungal community was almost equally affected by the addition of pure biogas slurry, chemical fertilizer and biogas slurry combined with chemical fertilizer (25.65–28.72%). Biogas slurry combined with chemical fertilizer significantly enriched Proteobacteria, Acidobacteria, Planctomycetes, Rokubacteria, and Ascomycota and depleted Chloroflexi, Bacteroidetes, Crenarchaeota, Basidiomycota, and Glomeromycota. The observation of the alteration of some bacteria- and fungus-specific taxa provides insights for the proper application of biogas slurry combined with chemical fertilizer, which has the potential to promote crop growth and inhibit pathogens.

Investigation on Microstructure and Properties of Duplex Stainless Steel Welds by Underwater Laser Welding with Different Shielding Gas.

Taking S32101 duplex stainless steel as the research object, underwater laser wire filling welding technology was used for U-groove filling welding. The influence of different shielding gas compositions on the ferrite content, microstructure, mechanical properties and pitting corrosion resistance was studied by simulating a water depth of 15 m in the hyperbaric chamber. The results show that, under the same process parameters, the size and proportion of austenite in the weld when using pure nitrogen as the shielding gas are larger than those protected by other shielding gases. In a mixed shielding gas, the increase in nitrogen content has little effect on the strength and toughness of the weld. Regardless of the shielding gas used, the base metal was the weakest part of the weld. At the same time, intermetallic inclusions have an adverse effect on the impact toughness of the weld. The pitting corrosion resistance of the welds depends on the Cr2N content in the heat-affected zone. The precipitation and enrichment of Cr2N causes local chromium deficiency, which is the main factor for the weak pitting corrosion ability of the heat-affected zone. Pure nitrogen protection has a better corrosion resistance than other gas protection.

The influence of thermal stability on the properties of Cu3N layers synthesized by pulsed magnetron sputtering method

In this paper, samples of copper nitride, a thermally unstable semiconducting material, were synthesized as layers, using the pulsed magnetron sputtering method. Synthesis was performed under different pure nitrogen pressure points, which aimed at obtaining layers differentiated in terms of their structure. The deposited layers have been subjected to heat treatment to achieve a better understanding of the thermal evolution of the structure of the material. A series of treatments were carried out in different temperatures starting from within studied one phase materials stability range (T∼230°C), through the intermediate range of a two-phase structure: Cu3N, Cu (∼230°C<T<330°C) up to the point of complete thermal decomposition (T∼400°C), enabling to better describe stoichiometry contributions of copper nitride to the thermal stability of the material. Crystalline phase and lattice constants of the deposited layers were characterized with X-ray diffraction measurements for samples from each temperature point. The phase composition was confirmed by Raman spectroscopy. Optical studies were performed by spectroscopic ellipsometry and resistivity by the Kelvin measurement method. Studies were evaluated and plotted as a function of annealing temperature. Deposited samples exhibited an anti-ReO3 polycrystalline structure with its lattice constant corresponding with literature data. The results showed changes in the structure of copper nitride layers induced by temperature. Higher temperatures caused visible structural changes. Depending on the stoichiometry of copper nitride layers, the thermal stability of the material was different. The reported changes were discussed and attributed to the stoichiometry of the material layers.

Does nitrogen application rate affect the moisture content of corn grains?

Nitrogen fertilizer application is an important measure to obtain high and stable corn yield, and the moisture content of corn grains is an important factor affecting the quality of mechanical grain harvesting. In this study, four different nitrogen fertilizer treatments from 0 to 450 kg ha–1 pure nitrogen were set for a planting density of 12.0×104 plants ha–1 in 2017 and 2018, and 18 different nitrogen fertilizer treatments from 0 to 765 kg ha–1 pure nitrogen were set for planting densities of 7.5×104 and 12.0×104 plants ha–1 in 2019, to investigate the effect of nitrogen application rate on the moisture content of corn grains. Under each treatment, the growth of corn, leaf area index (LAI) of green leaves, grain moisture content, and grain dehydration rate were measured. The results showed that, as nitrogen application increased from 0 to 765 kg ha–1, the silking stage was delayed by about 1 day, the maturity stage was delayed by about 1–2 days, and the number of physiologically mature green leaves and LAI increased. At and after physiological maturity, the extreme difference in grain moisture content between different nitrogen application rates was 1.9–4.0%. As the amount of nitrogen application increased, the corn grain dehydration rate after physiological maturity decreased, but it did not reach statistical significance between nitrogen application rate and grain dehydration rate. No significant correlation was observed between LAI at physiological maturity and grain dehydration rate after physiological maturity. In short, nitrogen application affected the grain moisture content of corn at and after physiological maturity, however, the difference in grain moisture content among different nitrogen application rates was small. These results suggest that the effect of nitrogen application on the moisture content of corn grains should not be considered in agricultural production.

Extended channel Hall thruster for air-breathing electric propulsion

Air-breathing electric propulsion is a promising concept that may allow sustained access to very low earth orbit by guaranteeing continuous drag compensation through in situ harvesting of propellant. For earth observation, such low orbits benefit image resolution and reduce signal latency and transmission power requirements, easing link budgets. Moreover, not having to carry typical electrostatic thruster propellants such as xenon and tanks positively impact overall mission costs. However, the low molecular mass and high first ionization energies of principal atmospheric constituents hinder efficient thruster operation and result in strongly degraded performance. In this study, we examine the performance of an extended channel Hall thruster design for air-breathing operations. An extended channel compensates for the reduced residence times of lighter neutrals. The longer channel, coupled with an extended radial magnetic field region, allows for an increased length of the ionization zone, enhancing molecular ionization probability. Here, we present direct thrust measurements of this thruster operating with a pure nitrogen flow. Analysis of the results show performance in the 500–800 W anode power range, with thrust, specific impulse, and total thrust efficiency ranging from 17 to 22 mN, 1000 to 1100 s, and 14% to 18%, respectively, with a constant 2 mg/s pure molecular nitrogen propellant flow. Performance tends to degrade with increased voltage, suggesting increased contributions of electron-molecule kinetics to performance losses, contrary to what is typically seen in the Hall thrusters operating with propellants such as xenon.

The microstructures and mechanical properties of martensite Ti and TiN phases in a Ti6Al4V laser-assisted nitriding layer

A fiber laser assisted the preparation of a nitride layer on the Ti6Al4V surface in a pure nitrogen atmosphere. Through SEM, XRD, and XPS analyses, the nitride layer is found to be mainly composed of dendritic TiN phase and an interdendritic α′-Ti phase. Not only the true crystal structure of the two main phases (TiN and α′-Ti) were directly characterized using TEM, but also the mechanical properties were tested by micro-indentation and nano-indentation methods for the first time.It is found that the nano-hardness of the TiN phase is 2609 HV, and the elastic modulus is 208 GPa. During the TiN dendritic fracture process, the primary dendrites undergo near ductile fracture along the growth direction of the secondary dendrites, and microcracks, bifurcations, deflection, etc. occur to form a crack-toughening mechanism. The nano-hardness of α′-Ti is 632 HV, and the elastic modulus is 142.8 GPa. The entanglement of two sets of parallel dislocations in α′-Ti crystals forms subgrain boundaries, which exert a positive influence on work hardening and fine-grain strengthening. • A large number of parallel dislocation groups in the generated TiN. • TiN dendrites not only have near ductile fracture, but also have crack toughening; • A large number of parallel dislocation groups and subgrain boundaries in the α′-Ti.

The Effect of Grazing Intensity on Vegetation Coverage and Nitrogen Mineralization Kinetics of Steppe Rangelands of Iran (Case Study: Nodoushan Rangelands, Yazd, Iran)

Livestock grazing can affect the cycling of nutritional elements in soil by making changes to the vegetation coverage. This study aimed to investigate the effect of rangeland exploitation on vegetation coverage and nitrogen kinetics. To this end, three experimental sites of light, moderate, and heavy grazing in Nodoushan rangelands of Yazd province were selected. The vegetation properties were then measured through systematic random sampling method and three to five bases along the transect were sampled from the current year growth of the dominant plants in the region. The soil samples were collected from 0–15 cm depth in five replications and mixed together to obtain a single composite soil sample on each site. In the first stage, nitrogen (N), carbon (C), C/N, cellulose, hemicellulose, and lignin of the sampled plant as well as nitrogen, carbon, lime, soil texture, saturation moisture percentage, pH, and electrical conductivity (EC) of the soil were measured. As the soil properties did not differ for light and moderate grazing soils, different treatments were conducted on the dominant species of light and heavy grazing sites with 1% organic carbon added to the rangeland soil. Nitrogen mineralization treatments were selected based on vegetation changes that, with increasing livestock grazing intensity, changed the predominance of plant composition from Artemisia sieberi and steppe to percentage Artemisia sieberi and Peganum harmala. The treatments included control, 100% Artemisia sieberi, 75% Artemisia sieberi and 25% Peganum harmala, 50% Artemisia sieberi and 50% Peganum harmala, 25% Artemisia sieberi and 75% Peganum harmala, and 100% Peganum harmala. The soil samples were incubated for pure nitrogen mineralization in three replications of 3 months. The results of nitrogen mineralization revealed that the immobilization of the treated soil with higher Artemisia sieberi and lower Peganum harmala was done at a more rapid rate during the first week. The immobilization was slowly reduced by the third week and then followed a growing rate. Overall, the results show that an increase in grazing intensity was associated with a change in vegetation coverage toward Peganum harmala species, the biochemical characteristics of which elevated the levels of pure nitrogen mineralization in soil.

Rapid Secondary Recrystallization of the Goss Texture in Fe81Ga19 Sheets Using Nanosized NbC Particles.

Herein, a simple and efficient method is proposed for fabricating Fe81Ga19 alloy thin sheets with a high magnetostriction coefficient. Sharp Goss texture ({110}<001>) was successfully produced in the sheets by rapid secondary recrystallization induced by nanosized NbC particles at low temperatures. Numerous NbC precipitates (size ~90 nm) were obtained after hot rolling, intermediate annealing, and primary recrystallization annealing. The relatively higher quantity of nanosized NbC precipitates with 0.22 mol% resulted in finer and uniform grains (~10 μm) through thickness after primary recrystallization annealing. There was a slow coarsening of the NbC precipitates, from 104 nm to 130 nm, as the temperature rose from 850 °C to 900 °C in a pure nitrogen atmosphere, as well as a primary recrystallization textured by strong γ fibers with a peak at {111} <112> favoring the development of secondary recrystallization of Goss texture at a temperature of 850 °C. Matching of the appropriate inhibitor characteristics and primary recrystallization texture guaranteed rapid secondary recrystallization at temperatures lower than 950 °C. A high magnetostriction coefficient of 304 ppm was achieved for the Fe81Ga19 sheet after rapid secondary recrystallization.

Numerical investigations of nanosecond surface streamers at elevated pressure

Single-pulse nanosecond surface dielectric barrier discharges operated in synthetic air and pure nitrogen at elevated pressure (6 bar) have been numerically studied by the classical fluid method. The aim of this work is to provide the necessary basis for analyzing the surface streamer-to-filament transition phenomenon. The electrical parameters, discharge morphology and propagation dynamics, as well as the possible influence of photoionization, kinetics and gas heating on the surface streamer stage at elevated pressure are discussed in a combined numerical-analytical way. A good agreement between measurement, numerical simulation and analytical estimation is achieved. The streamer thickness is derived to be inversely proportional to the pressure, the average reduced electric field in the streamer channel ranges from 75–150 Td, and the average electron density in the channel is ∼1022 m−3 for both polarities. The characteristic time of electron decay in the positive streamer channel is only on the order of ∼1 ns due to high charge exchange and electron-ion recombination rates. Photoionization provides an ionization source of 1027–1028 m−3 s−1 in front of the streamer head for both gases. Stepwise ionization/dissociation significantly affects the discharge dynamics of negative polarity SDBD, while for positive polarity this influence is negligible. The fast gas heating could lead to ±0.15 cm change of the positive streamer length. The secondary surface ionization wave is numerically observed, providing a time duration 0.25–0.5 ns of high electric field (230 Td), making it possible for streamer-to-filament transition kinetics to take place.

Energy characterization of an innovative non-equilibrium plasma ignition system based on the dielectric barrier discharge via pressure-rise calorimetry

A dielectric barrier discharge igniter (BDI) ensures engine stable combustion at lean and/or diluted conditions by the generation of non-equilibrium low-temperature plasma (LTP), strong promoter of the ignition, in a wide mixture volume.Beside this, a substantial amount of thermal energy is also released in the medium to enhance the chemical reactions of fuel oxidation. Therefore, the measurement of thermal energy is crucial to characterize the igniter capability to guarantee a robust combustion onset and it can be performed only in controlled environments.In this work, a Radio-Frequency BDI was tested via pressure-based calorimetry by evaluating the thermal energy released during the discharge in a controlled environment represented by a constant volume vessel. The corresponding thermal efficiency was evaluated as well. Pure nitrogen and air were exploited at engine-relevant pressure levels by varying the discharge features as its time duration and intensity (the latter by peak electrode voltage variation), to fully characterize the igniter behavior.Both media showed similar trends of absorbed and released energy but differences up to 50% were found for the latter. This trend was found to be linear, unexpectedly in contrast to the quadratic one showed by the LTP corona streamer-type igniter (CSI). Furthermore, the thermal energy dependence from pressure showed a change up to complete independence at a specific electrode value. To provide an explanation for such different behaviors, a comparative analysis between the diverse discharges of the two igniters was carried out. Moreover, by varying voltage and duration, the device was found to be able to release up to 60 mJ in the tested point with very low dispersion, essential to guarantee stable combustion ignition at challenging operating conditions for next-generation internal combustion engines.

BLEND OF METAL OXIDES AND POLYANILINE ON PLATINUM ELECTRODES FOR DISSOLVED OXYGEN SENSORS

In this study, we report the detection of dissolve oxygen (DO) by using a blend of Ruthenium oxide and polyaniline (PANI) coated on platinum electrodes. Optical properties of the PANI were characterized by using Ultraviolet - Visible (UV-Vis) and Fourier-transform infrared (FTIR) spectroscopy. In order to study the sensitivity of the thin films of the PANI and PANI: Ruthenium oxide blend, cyclic voltammetry (CV) measurements was performed with the platinum electrodes coated with the thin films of PANI: Ruthenium oxide. The electrolyte solutions were prepared from the phosphate buffer and had the salinity of 20‰ and pH 7.3. The CV measurements were carried out when the electrodes were put in the electrolyte solutions which had various DO concentrations by purging pure nitrogen and oxygen gases. The DO concentrations in the experiments were measured by a commercial dissolved oxygen probe. The correlation between the current in the CV measurements and DO concentrations was determined. The effect of the blending ratio of the metal oxide and PANI on the electrochemical signal was also specified. The results showed that the platinum electrodes with PANI: Ruthenium oxide blend coating exhibited a high possibility as electrochemical sensor for detection of low levels of DO in aqueous phase.

Experimental Validation of a Novel Generator of Gas Mixtures Based on Axial Gas Pulses Coupled to a Micromixer.

In this work, a novel generator of gas mixtures previously numerically investigated and based on axial gas pulses coupled to a micromixer has been conceived, manufactured, and validated. Standard gaseous pollutant mixtures and pure nitrogen or pure air were introduced in a microdevice designed to generate alternating axial gas pulses which were downstream homogenized by means of a multi-stage modular micromixer. The dilution, and therefore the final pollutant concentration, was controlled by two parameters: the ratio between the times of each of the two gas pulses and the partial pressure of the pollutant(s) mixture added to the device. The gas mixture generator was coupled to an analyzer to monitor the concentration of aromatic pollutants. The response time was optimized to be lower than 2 min in accordance with the analytical instrument. The quantity of pollutants measured at the micromixer’s outlet increased linearly with the expected gas concentration of 3.7–100 ppb generated by this novel microfluidic generator and fitted perfectly with those obtained by a reference gas dilution bench. At 5 ppb, the precision on the concentration generated is close to that obtained with the conventional gas mixing bench, i.e., around 10%.

Modeling of fast ionization waves in pure nitrogen at moderate pressure

The fast ionization wave (FIW) discharges in pure nitrogen in a capillary tube at 27 mbar, initiated by positive polarity, high-voltage nanosecond pulses, are numerically studied by coupled two-dimensional plasma fluid modeling. The 2D fluid code based on local mean energy approximation is validated and used, an extended three-exponential Helmholtz photoionization model is proposed for pure nitrogen. The development and structure of the nitrogen FIW is analyzed, the electric field and current are calculated compared with experimental measurements. The evolution of radial distribution of electrons and N2(C 3Π u ) during the FIW development stage and in the afterglow are analyzed, the radial profiles of electron density show a ‘hollow’ structure in the FIW development stage, the temporal-spatial evolution of N2(C 3Π u ) is dominated by the competition between the pooling reaction of and the quenching by electrons. The role of photoionization on the nitrogen FIW radial morphology is discussed, the equivalent background electron density of photoionization in nitrogen discharge is suggested to be (4–6) × 1013 m−3. Spatial distribution of specific energy deposition (SED), fast gas heating (FGH) energy and temperature rise are obtained, heating efficiency varies with electric field E/N and SED and tends to be 10% at high SED. The dominating reactions responsible for FGH and their fractional contribution in space and time are analyzed, in the near axis region, pooling reactions of and N2(B 3Π g ) contribute up to 80% FGH energy, electron impact dissociation of molecular nitrogen contributes about 10%, while e- recombination and quenching of N(2 D) atoms by N2 molecules contribute rest.

Effects of Combined Application of Chemical Fertilizer and Microbial Fertilizer on the Chemical Components Contents of Flue-Cured Tobacco Leaves

[Objective] To determine the effect of microbial fertilizer combined with compound fertilizer on the chemical composition content of flue-cured tobacco leaves. [Method] Before planting the flue-cured tobacco, the local conventional fertilizer varieties and microbial fertilizer were applied to tobacco pond annular hole according to the conventional dosage. The experiment has four groups with different treatments, namely T1: without any fertilization; T2: 4 kg of pure nitrogen per mu, applying humic acid organic-inorganic compound fertilizer with 50 g/plant when planting tobacco; T3: reducing the total amount of conventional fertilization by 50%, and applying 80 g/plant of microbial fertilizer; T4: applying only 80 g/plant of microbial fertilizer. The trial adopted a randomized block design, with 3 replicates for each treatment. After the tobacco leaves were harvested and cured at the maturity stage, 5 kg of the lower (X2F), middle (C3F) and upper (B2F) first-cured samples were taken for chemical composition determination and analysis. [Results] The results show that T3 treatment can effectively increase the total sugar, reducing sugar, total nitrogen, nicotine, potassium, and chlorine content in X2F, C3F, and B2F grade tobacco leaves, which ratios are between 20.10% ∼ 21.03% and 18.90% ∼ 19.90%, 2.68% ∼ 3.26%, 2.28% ∼ 3.15%, 2.21% ∼ 2.50%, 0.56% ∼ 0.72%, meeting the production standards of high-quality tobacco. Secondly, T4 treatment can significantly improve the sugar-alkali ratio, nitrogen-alkali ratio, and potassium-chloride ratio of X2F grade tobacco leaves, and it can improve the sugar-nitrogen ratio of C3F and B2F grade tobacco leaves, but the effect is not significant; T3 treatment has a significant effect on B2F grade tobacco. The nitrogen-nitrogen ratio of tobacco leaves has a significant effect on improving the sugar-nine ratio, potassium-chloride ratio and the sugar-nitrogen ratio of X2F ∼ B2F grade tobacco leaves, but the effect has not reached a significant level. [Conclusion] Microbial fertilizer combined with compound fertilizer can improve the content of chemical components in flue-cured tobacco. On the whole, the application effect of T3 treatment is better, that is, the application effect of 80 g/plant microbial fertilizer and 50% reduction of conventional chemical fertilizer is more ideal.

Experimental Study of Absorbent Hygiene Product Devolatilization in a Bubbling Fluidized Bed

This paper aims to investigate the usage of waste from Absorbent Hygienic Products (AHP) as a fuel for gasification or pyrolysis, two attractive routes to obtain valuable products and dispose of this kind of waste. The study experimentally investigated the devolatilization of coarsely shredded materials from diapers, in a laboratory-scale bubbling fluidized bed made of sand, as a representative preparatory step of the above-mentioned thermochemical conversions. Two versions of shredded materials were considered: as-manufactured diapers (AHPam, as a reference), and the cellulosic fraction of sterilized used diapers (AHPus). Results were presented, obtained from physical-chemical characterization of AHPam and AHPus (TGA, CHNS/O, proximate and ultimate analyses, XRF, ICP-AES, SEM-EDS), as well as from their devolatilizations at 500–600–700–800 °C under two different atmospheres (air plus nitrogen, or pure nitrogen as a reference). Generally, temperature influenced syngas composition the most, with better performances under pure nitrogen. At 700–800 °C under pure nitrogen, the highest syngas quality and yield were obtained. For AHPam and AHPus, respectively: (i) H2 equaled 29.5 vol% and 23.7 vol%, while hydrocarbons equaled 14.8 vol% and 7.4 vol% on dry, dilution-free basis; (ii) 53.7 Nl and 46.0 Nl of syngas were produced, per 100 g of fuel. Overall, AHP emerged as an interesting fuel for thermochemical conversions.