Generation Of Nitrogen Oxides Research Articles

EFFECT OF TURNING THE FLOW OF SECONDARY AIR IN THE BOILER'S BURNER SYSTEM ON THE THERMAL AND GAS DYNAMICS OF THE BOILER FIRING SPACE AND THE PROCESS OF FORMATION OF NITROGEN OXIDES IN THE ACTIVE COMBUSTION ZONE

The aim of the work is computer simulation of the formation of nitrogen oxides in the combustion zone of the boiler of the CCI 312 with different twists of secondary air in the boiler burners. The organization of the vortex flow allows to reduce the generation of nitrogen oxides due to the formation of a return flow, which ballasts the combustion zone by oxidation products. The limitation of this technique is to reduce the combustion temperature, which can lead to underburning.
 The objective of the study is to determine the formation of nitrogen oxides based on computer simulation of the thermogas dynamics of the firing space of the boiler Chamber of Commerce and Industry 312 DTEK Ladyzhinskaya TPP when burning gas coal using spinning blades in the secondary air channels of the burners.
 The following variants of the secondary air flow in the burners were investigated: 1) without twisting the flow, both in the outer annular channels and in the internal channels of the burners (the variant is taken as the baseline for comparison); 2) 8 blades in the outer annular channels in their absence in the internal channels; 3) 24 blades in the outer annular channels in their absence in the internal channels; 4) 8 blades each, both in the outer annular canals and in the internal canals; 5) 24 blades, both in the outer annular canals, and in the internal canals.
 With an increase in the number of blades, the pressure drop increased, which was necessary to overcome their resistance. The greatest effectiveness of the use of turbulent blades is observed in the range of their total number from 8 to 16.
 The expression for the relative change of the amount of nitrogen oxide emissions and the fan power required to overcome the resistance of turbine blades was obtained.

The combustion and NOx emission characteristics of the ultra-low volatile fuel using the novel pulverized coal self-sustained preheating combustion technology

The pyrolysis semi-char and gasification fly ash, as the by-product of coal pyrolysis and gasification technology, have difficulties in combustion application due to its ultra-low volatile content. As a potential combustion technology, the novel pulverized coal self-sustained preheating combustion technology for the fuel with the ultra-low volatile was developed. The 16 MW novel self-sustained preheating combustion pilot plant was constructed and used for the study. The operation characteristics of the novel internal fluidized bed combustor (IFBC) for pulverized coal preheating and the effects of the secondary air on combustion and nitrogen oxides (NOx) emissions were investigated. The results showed that the fuel could be preheated up to 900 °C continuously and steadily by the IFBC and then fed into the furnace to burn stably. The combustion efficiency was higher than 96% with the lowest NOx emission of 110.0 mg/m3 (@6% O2). The flame images exhibited most areas were red while the marginal area was blue. With the decrease of the secondary air ratio, the flame length and the ignition delay distance decreased, and the flame profile became blurred. Meanwhile, the NOx emissions firstly decreased and then increased with the lowest value at the secondary air ratio of 0.39. The decrease of the momentum ratio of inside secondary air to outside secondary air had a certain effect on inhibiting NOx generation until the ratio dropped to less than 0.6.

Study on combustion and nitrogen oxide emissions of gas boiler

In order to reduce the emission of nitrogen oxides in gas-fired boilers, the effects of excess air ratio and flue gas recirculation on nitrogen oxide emissions during natural gas combustion are studied by numerical calculation. By adding flue gas recirculation, the generation of nitrogen oxides is significantly reduced. When the flue gas recycling rate is 20%, the emission of nitrogen oxides is minimized to about 40 mg/m3.

The Generation and Suppression of NOx and N2O Emissions in the Oxy-Fuel Combustion Process with Recycled CO2 (an Overview)

It is shown that combustion of solid fuels in an oxygen atmosphere with recycled flue gases is an efficient method for capture of CO2. The use of the circulating fluidized bed (CFB) technology in the oxy-fuel combustion process reduces the CO2 capture costs and nitrogen oxide emissions compared with flare combustion. The mechanisms of generation and suppression of nitrogen and nitrous oxides during CFB combustion of solid fuels are considered. The basic reactions that occur during the exit and burning of volatiles and combustion of char resulting in generation of NO, N2O, and N2 are indicated. The effect of the secondary air delivery on nitrogen oxide emissions is studied. It is shown that the degree of converting fuel nitrogen into N2O is reduced when the degree of converting nitrogen into NOx is increased. Comparative analysis that the effect of flue gas recycling and other process factors has on generation of NO and N2O during combustion in air, oxygen, and CO2 has been made. It is shown that, owing to recycling, the fractions of NOx and N2O generated from fuel nitrogen during oxy-fuel combustion are significantly lower than those during combustion in air. Mathematical simulation of various complicated processes related to generation and suppression of hazardous pollutant emissions has recently become a generally accepted method that allows the prediction at relatively low costs of such processes during the combustion of various fuels. However, as applied to new technologies for combustion of various biomass types and cofiring of coal and biomass, these methods have not yet been properly developed. The most preferable mathematical models for calculating nitrogen oxide emissions are provided, and the predicted results are compared with experimental data. The lines of further research, predominantly in the simulation of cofiring of coal and biomass, are outlined. It is shown that comprehensive investigations of generation and suppression of hazardous pollutant emissions during cofiring of coals and biomass of various kinds, in particular, during oxy-fuel combustion with recycled CO2 are of topical interest.

Optimization and control of NOx in coke oven vertical flue under flue gas recirculation

The orthogonal experimental design with CFD simulation was carried out to simulate combustion in the coke oven vertical flue at external flue gas recirculation. The control of nitrogen oxides (NOx) generation was analysed by different factors such as air excess coefficient, oxidant preheating temperature, flue gas recirculation and oxidizer inlet cross-sectional area ratio. The simulation results showed that the the orthogonal experimental design with CFD had a significant effect on the combustion process. The flue gas recirculation ratio effectively improved the temperature distribution uniformity in the vertical flue, and had a significant effect on NOx production in the vertical flue. Within the parameters of the orthogonal design, when the air excess coefficient was 1.1, the oxidant preheating temperature was 1200 K, the flue gas recirculation ratio was 30%, and the oxidant inlet cross-sectional area ratio was 0.5, the NOx production in the coke oven vertical flue was the smallest, lower than the industry emission standard.

SLOW-UP GENERATION OF NITROGEN OXIDES BY TURNING THE PRIMARY AIR FLOW IN THE SWIRL BURNER OF THE BOILER TPP 312

The aim of the work is computer simulation of the formation of nitrogen oxides in the furnace of the boiler TPP 312 with the swirl of the primary air in the boiler burners. The organization of the vortex flow allows reducing the generation of nitrogen oxides due to the formation of a return flow, which ballasts the combustion zone by oxidation products. The limitation of this technique is the reduction of the combustion temperature which can lead to underburning.
 The objective of the study is to determine the formation of nitrogen oxides based on computer simulation of the gas dynamics of the firing space of the boiler TPP 312 DTEK Ladyzhyn TES when swirling streams of air are used in the burner channels.
 Efficient combustion of fuel, in particular solid, is ensured by three factors: mixing of the fuel and the oxidizing agent, residence time in the temperature zone necessary for the combustion of fuel particles and temperature. The selection of the parameter is under pressure from requirements operating in opposite directions. On the one hand, a higher temperature contributes to better fuel burning, but, on the other hand, the formation of nitrogen oxides increases at a higher temperature.
 Analysis of the data on the quality of coal that comes to the station made it possible to derive the averaged characteristics of coal that were used to improve the combustion model of the software package.
 Conclusions
 In the presence of swirling flow, the maximum temperature is 108 K lower than in the case of a direct-flow burner, which causes a 5% reduction in the generation of nitrogen oxides. Centrifugal flows created a rarefaction zone at the burner axis and the reaction products begin to heat the fuel mixture in the burner itself. The surface area of ​​the beginning of combustion during the application of twisting reduces by 30%.
 The results of the study showed that the twisting of the primary air does not lead to a significant reduction of nitrogen oxides.

Driving force analysis of the nitrogen oxides intensity related to electricity sector in China based on the LMDI method

Abstract In China, as a kind of important precursors to cause PM2.5 and O3 pollution, nitrogen oxides (NOX) have attracted a large attention. From the perspective of electricity-related NOx generation, the aggregate nitrogen oxides generation intensity (ANI) is decomposed temporally and spatially based on the LMDI method. At the country level, ANI in China dropped significantly from 2.90 g NOX/kWh to 2.15 g NOX/kWh from 2000 to 2016. The temporal and spatial decomposition results showed that the major driving forces are the clean energy penetration (Ucp) and thermal power generation efficiency (Uint), which decreased ANI by 10.5% and 7.74% during the study period, respectively. Ucp in the southwestern, central and northwestern regions were the main contributors for ANI reduction. Uint in the eastern region was the main contributor in reducing ANI. Based on our findings, it is suggested to provide different NOX emission reduction policies for different provinces. Thus, these approaches will improve initiatives of reducing NOX emission from source.

Spatially differentiated effects of socioeconomic factors on China's NOx generation from energy consumption: implications for mitigation policy

Nitrogen oxides (NOx) has become the priority of China's air pollution control, but the regional socio-economic factors responsible for NOx generation are embedded with spatial disparities, which leads to different effects of air quality policy at the local level. This study applied a geographically weighted regression (GWR) model to investigate the drivers of NOx generation from energy consumption (NGEC) in China's 30 provinces, to explore nonstationary spatial effects of NGEC. The results showed that population size has always been the dominant factor in spatial NGEC across all regions of China, although there is a minor north-south difference. However, the effect of per capita GDP and energy intensity leads to a significant north-south difference when they are influencing NGEC, which shows a minor west-east difference from thermal power generation (TE). We also found that in Northern and Northeast China, the transition towards cleaner energy structure based on natural gas has started correlating significantly with NOx generation through a weakly negative effect in 2015. Our findings show alternative strategies on NOx reduction, which include the spatially differentiated effect of regional socioeconomic factors on energy consumption.

Kinetics of the nitrogen oxides reaction with coke carbon in a low-temperature swirl furnace process

The work is devoted to the increase of ecological parameters of organic fuel burning process in power boilers combustion chambers. The technological method of nitrogen oxides decomposition on the surface of carbon particles with the formation of environmentally safe carbon dioxide and molecular nitrogen in low-temperature swirl combustion is considered. A methodology, a mathematical model and a program for calculating the process of a fuel combustion under conditions of multiple circulation, with periodic return of fuel particles to zones with the initial concentration of oxygen, are developed. It is shown that the stepwise supply of the oxidizer to the flare leads to a decrease in the generation of toxic nitrogen oxides, the formation of reducing zones, and the decomposition of the formed nitrogen oxides on the surface of burning coke particles. It has been established that the amount of decomposed nitrogen oxides depends on the surface area of the reacting fuel particles, as well as the time of their stay in the swirl zone of the low-temperature swirl furnace. With the use of calculated results, emissions of nitrogen oxides of reconstructed boilers are reliably predicted.

Numerical Investigation on Co-firing Characteristics of Semi-Coke and Lean Coal in a 600 MW Supercritical Wall-Fired Boiler

Semi-coke is one of the principal by-products of coal pyrolysis and gasification, which features the disadvantages of ignition difficulty, low burnout rate, and high nitrogen oxides (NOx) emission during combustion process. Co-firing semi-coke with coal is a potential approach to achieve clean and efficient utilization of such low-volatile fuel. In this paper, the co-firing performance of semi-coke and lean coal in a 600 MW supercritical wall-fired boiler was numerically investigated which has been seldom done previously. The influences of semi-coke blending ratio, injection position of semi-coke, excess air ratio in the main combustion zone, the co-firing method, and over fire air (OFA) arrangement on the combustion efficiency and NOx generation characteristics of the utility boiler were extensively analyzed. The simulation results indicated that as the blending ratio of semi-coke increased, the NOx emission at furnace outlet decreased. The blending methods (in-furnace versus out-furnace) had certain impacts on the NOx emission and carbon content in fly ash, while the in-furnace blending method showed more flexibility in co-firing adjustment. The injection of semi-coke from the upper burners could significantly abate NOx emission at the furnace outlet, but also brought about the rise of carbon content in fly ash and the increase of outlet temperature. Compared with the condition that semi-coke and lean coal were injected from different burners, the burnout ratio of the blend premixed outside the furnace was higher at the same blending ratio of semi-coke. With the excess air ratio in the main combustion zone increased, NOx concentration at the furnace outlet was increased. The excess air ratio of 0.75 in the main combustion zone was recommended for co-firing 45% semi-coke with lean coal. The operational performance of the boiler co-firing semi-coke was greatly affected by the arrangement of OFA as well. The amount of NOx generated from the supercritical wall-fired boiler could be reduced with an increase of the OFA height.

Hydrothermal processing of β-glucan from Aureobasidium pullulans produces a low molecular weight reagent that regulates inflammatory responses induced by TLR ligands

The Kururu no β-glu® (KBG) is a commercial hydrothermal-treated Aureobasidium pullulans β-glucan produced by a unique hydrothermal process that results in high solubility of the β-glucan. In this study, we examined the biological activities of this reagent. RAW264.7 cells do not express Dictin-1 on the cell surface, but cells still respond to various pathogen molecular patterns. Lipopolysaccharide (LPS) induced nitrogen oxide (NO) synthesis and TNF−α production in RAW264.7 cells, and those were suppressed by KBG in a dose-dependent manner. The major signaling cell surface receptor respond to LPS is the TLR4/MD-2 complex. The UT12 antibody against to the TLR4/MD-2 complex mimics LPS function and induces cell responses. NO generation and TNF-α production were similarly induced in cells by stimulation with the antibody, but those were not suppressed by KBG. Cell responses induced by other TLR ligands, such as CPG (TLR9 ligand) and Pam3CSK4 (TLR1/TLR2 ligand), were also suppressed by KBG. Therefore, the target molecule for KBG is different from TLR receptors and Dictin-1. Although we also examined the suppressive activities of several other β-glucan products, comparable activities were not detected with other reagents. A unique hydrothermal process may produce the active reagent. Reprocessing KBG increased low molecular weight fractions, and suppressive activities were markedly enhanced. Therefore, low molecular weight fractions obtained by hydrothermal processing of KBG may result in potential reagents that control inflammation induced by various pathogens.

ДОСЛІДЖЕННЯ РІВНІВ ФІЗИЧНИХ ФАКТОРІВ У ПРИМІЩЕННЯХ ДИСПЕТЧЕРСЬКИХ СЛУЖБ АЕРОПОРТІВ ЦИВІЛЬНОЇ АВІАЦІЇ

Предметом представленої роботи є процеси формування комплексу фізичних факторів у приміщеннях диспетчерських служб аеродромів цивільної авіації. Мета дослідження – натурні вимірювання кількісних значень найбільш критичних фізичних факторів та надання науково обґрунтованих рекомендацій з їх нормалізації та підтримання на нормативному рівні. Для досягнення поставленої мети визначені наступні задачі: вимірювання напруженостей магнітного та електричного полів промислової частоти, індукції стаціонарного магнітного поля, густини потоків енергії електричних полів, радіочастот, напруженостей електростатичних полів та концентрації аероіонів обох знаків у повітрі робочої зони. На основі отриманих даних розроблені рекомендації з управління та підтримки стандартного рівня виміряних фізичних факторів. Методами досліджень є інструментальні вимірювання рівнів фізичних факторів, розрахунковий та графоаналітичний методи. У результаті вимірювань рівнів фізичних факторів у диспетчерських вежах аеропортів встановлено наступне. Напруженості магнітного та електричного полів промислової частоти, густини потоків енергії електромагнітних випромінювань радіочастот, стаціонарних магнітних полів перебувають на нормативному рівні та не потребують коригування. Повітря робочої зони є повністю деіонізованим. Це обумовлене наявністю ненормативних рівнів електризації полімерних поверхонь. Цей висновок зроблено на основі виконаного моделювання відповідних процесів та підтверджено експериментально. Для нормалізації аероіонного складу повітря рекомендовано використовувати спеціально розроблений ультразвуковий іонізатор повітря. Його перевагою є відсутність генерації озону та оксидів азоту у процесах коронних розрядів. Досліджено ефективність розробленого іонізатора повітря. Показано, що зона впливу іонізатора задовільна, при цьому відбувається підвищення відносної вологості. Це сприяє зниженню електризації поверхонь. Зроблено висновки про фактичний стан рівнів фізичних факторів. У приміщеннях диспетчерських служб аеропортів доведено необхідність нормалізації аероіонного складу повітря і надано спосіб її реалізації.

Numerical simulation on combustion process of a hydrogen direct-injection stratified gasoline Wankel engine by synchronous and asynchronous ignition modes

A Wankel engine with hydrogen direct-injection enrichment is recognized as an attractive method to enhance combustion efficiency. In this paper, on the basis of the chemical kinetic mechanisms, a three-dimensional simulation model was established and validated by the measured results. The ignition and combustion processes in a gasoline Wankel engine with hydrogen direct-injection enrichment were implemented for numerical simulation. The influence of twin-spark timing was firstly analyzed by synchronous ignition. Further investigation was then conducted to simulate how to effect the combustion by asynchronous ignition based on the favorable synchronous ignition timing. Results showed that, the average flow velocities were 18.8, 20.7, 23.6, and 25.4 m/s for the spark timings (ST) of 45, 35, 25, and 15°CA BTDC respectively. With retarded ST, the rich equivalence ratio approached to twin-spark plug continually. For synchronous ignition, at a larger advance of ST, the duration between the timing of the vortex dissipation and ST was longer, and the ignition delay was more prolonged. As the ST advanced, the combustion rate was enhanced with the increment in chamber temperature, the reactants (C8H18, C7H16, and H2) consumption and intermediates (H2O2, OH, and CH2O) generation were accelerated, the maximum H2O2 and CH2O decreased whereas the maximum OH increased, and nitrogen oxides (NOx) and carbon monoxide (CO) increased sequentially. For asynchronous ignition, the accelerated flame front was in accordance with the rotating direction of the rotor while the opposite direction was inhibited during the combustion process. An earlier ignition of leading-spark plug (L-plug) or trailing-spark plug (T-plug) provided the higher flame speed and faster H2 consumption, which contributed to the higher in-cylinder pressure, combustion temperature, and NOx and CO production. The preferable ignition and combustion characteristics was realized when the L-plug angle was 25°CA BTDC, and the T-plug angle was 35°CA BTDC. Compared with the favorable synchronous ignition timing, the flame propagation and H2 consumption were expedited, the peak pressure increased by 2.8%, the corresponding crank position advanced by 3°CA and there was no increase in NOx and CO generation. Therefore, it was recommended in engineering applications that the ST of T-plug advanced appropriately while the ST of L-plug remained constant.

Molecular mechanisms of oxidation damage andlivercell dysfunction in patients withmetastatic colorectal cancer.

Interaction between tumor cells and tumor microenvironment is critical for homeostasis of normal cells and tumor growth. Tumor cell- stroma interaction represents the potent factor able to initiate cancer and affect tumor progression and disease outcome. The tumors vary by their origin and microenvironment (proportion of stromal cells, their composition and activation state). The surgical stress and tumor microenvironment may potentiate acute hepatic failure in the patients with metastatic colorectal cancer(mCRC). Pathological effect of ischemia-reperfusion (I/R) consists in the increased generation of superoxide radicals(SR) and nitrogen oxide(NO) affecting the postresectional regeneration of liver tissue. Redox state of hepatic tissue in I/R setting upon resection of metastases may trigger the aggressiveness of residual cancer cells and regeneration or degradation of hepatic tissue. The aim of the study was to analyze redox state of hepatic tissue following surgery with Pringle maneuver(PM) in the patients with mCRC. mCRC samples from 145patients treated at National Cancer Institute, Ministry of Health of Ukraine, were analyzed. The patients obtained chemotherapy according to the approved international and national standards as well as clinical protocols. Two groups of patients were delineated according to the duration of the interruption of blood inflow due to PM, namely ≤45min and >45min. The activity of FeS proteins in the electron transport chain (ETC) in mitochondria and lactoferrin (LF) level in the tissues were assessed by EPR (77К). The rates of SR and NO generation were determined with spin traps. The activity of matrix metalloproteinase(MMP)-2 and -9was measured by gelatin zymography using SDS-polyacrylamide gel electrophoresis. In tissue of liver resected in the setting of > 45min ischemia, ETC function in mitochondria was impaired (decreased activity of FeS protein of N-2 ETC complex I due to interaction with NO). This results in the hypoxia state and glycolysis with uncontrolled SR generation. In addition, the efficiency of detoxification system in hepatocytes is reduced substantially with increase in semiquinone and LF levels as well as MMP-2and-9 activity as compared with liver without metastatic lesions that was not affected by I/R. The ischemic injury of liver in the setting of metastasis resection results from cell response to interruption of blood flow followed by reperfusion. The key factor in the genesis of reperfusion damage is uncontrolled increase of the levels of SR and their metabolites- reactive oxygen species as well as the increased MMP activity. Also, liver tissue affected by I/R contains high levels of xanthine oxidase metabolizing hypoxanthine and monoamine oxidase deaminizing biogenic amines. Both processes are the sources of SR.

OXIDATIVE AND MUTAGENIC EFFECTS OF LOW INTENSITY GSM 1800 MHz MICROWAVE RADIATION

Despite a significant number of epidemiological studies on potential carcinogenicity of microwave radiation (MWR) from wireless devices and a bulk of experimental studies on oxidative and mutagenic effects of low intensity MWR, the discussion on potential carcinogenicity of low intensity MWR is going on. This study aims to assess oxidative and mutagenic effects of low intensity MWR from a typical commercial model of a modern smartphone. The model of developing quail embryos has been used for the assessment of oxidative and mutagenic effects of Global System for Mobile communication (GSM) 1800MHz MWR from a commercial model of smartphone. The embryos were exposed in ovo to 0.32µW/cm2, discontinuously- 48s- On, 12s- Off, during 5days before and 14days through the incubation period. The exposure of quail embryos before and during the incubation period to low intensity GSM 1800MHz has resulted in expressive statistically significant oxidative effects in embryonic cells, including a 2-fold increase in superoxide generation rate and 85% increase in nitrogen oxide generation rate, damages of DNA integrity and oxidative damages of DNA (up to twice increased levels of 8-oxo-dG in cells of 1-day old chicks from the exposed embryos). Finally, the exposure resulted in a significant, almost twice, increase of embryo mortality. The exposure of model biological system to low intensity GSM 1800MHz MWR resulted in significant oxidative and mutagenic effects in exposed cells, and thus should be recognized as a significant risk factor for living cells.

Theoretical study of the effect of hydrogen radicals on the formation of HCN from pyrrole pyrolysis

As a typical fossil fuel, coal is a major contributor to nitrogen oxide (NOx) pollution. The detailed mechanism of NOx generation from coal pyrolysis need to be clarified. Within this research, we used density functional theory (DFT) to investigate the formation mechanism of HCN as a NOx precursor during pyrolysis of pyrrole in the presence of hydrogen (H) radicals. Firstly, three different reaction positions for hydrogen radical attacking were compared. It was identified that hydrogen radical initially reacts with pyrrole at the location adjacent to N through a single elementary reaction step with an activation energy of 77.12 kJ/mol. Additionally, to examine the role of hydrogen radical in the pyrrole pyrolysis to form HCN, 12 subsequent reaction pathways were theoretically investigated. It was found that one of the pathway (Pathway a-4) involving hydrogen transfer followed by carbon-carbon cleavage processes is the route with the lowest energy barrier of all of the mechanisms reported, thus it plays an important role in the formation of HCN from the pyrrolic components of coal. These results further indicated that the hydrogen radicals significantly reduce the energy barrier of the pyrrole pyrolysis.

Studying and substantiation of the method for normalization of air­ionic regime at industrial premises at the ultrasonic ionization of air

We report results of investigations on normalization of the air-ionic mode at premises with ultrasonic ionization of humidified air. We substantiated an increase in the concentration of negative air-ions with complex influence of the balloelectric effect and ultrasonic cavitation. We established that the concentration of negative air-ions increases almost in six times at the use of distilled water as a source of air-ions under the action of an ultrasonic generator with a power of 10 W at a distance of 0.5 m. At the same time, there is no generation of ozone and nitrogen oxides due to the combined influence of ultrasonic cavitation in a surface layer of water and the balloelectric effect. We proved that the concentrations of negative and positive air-ions increase due to changes in physical-and-chemical properties of water and the emerging mechanical-and-chemical phenomena with a decrease in the degree of water mineralization of water. We proposed a mechanism for formation of air-ions in the humidified air of industrial premises under the combined action of the balloelectric effect and ultrasound. We substantiated that improvement in the quality of the air-ionic composition of air in industrial premises takes place at a temperature of demineralized water of 20‒25 °C and a directed airflow of 6 m/s towards a working zone, with the combined action of the balloelectric effect and ultrasound, which improves sanitary and hygienic working conditions. We proposed a structure of an automated control system for the air-ionic mode of a working area of industrial premises under artificial air-ionization with a use of an air-ions generator and a ventilation system. It will make possible monitoring and processing of information on technological, electrical and microclimatic parameters, adjusting, coordination of work and joint managing of devices of a ventilation system and an ultrasonic generator of air-ions

Acoustic waves effect on the generation of nitrogen oxides by corona discharge in air

We studied the interaction of acoustic waves with negative corona discharge in air at atmospheric pressure. The application of acoustic waves on the discharge causes a mixing of ambient air with the gas between the electrodes, which results in cooling of the gas in the inter-electrode gap. As a rough indirect indicator of the discharge cooling, we used a concentration of nitrogen oxides generated by the discharge. We chose these oxides because they exhibit antibacterial properties. We showed that for a particular discharge power with increasing amplitudes of acoustic displacements, the concentration of generated nitrogen mono/dioxide decreases, and that this decrease could be attributed mainly to the temperature. We also found that application of acoustic waves on the discharge for a particular power substantially decreases transient spark frequency, increases the magnitude of the streamer onset voltage, and increases the difference between the streamer and spark onset voltage.

NH3 sensing properties and mechanism of Ru-loaded WO3 nanosheets

In this paper, WO3 nanosheets were prepared by an acidification method and Ru catalyst was loaded on the surface of nanosheets through a conventional impregnation process. NH3 gas sensors based on the neat and Ru-loaded WO3 nanosheets were fabricated by the scree-printing technique and their sensing properties to NH3 were investigated. The morphologies and surface structures of neat and Ru-loaded WO3 nanosheets were analyzed. It is revealed that WO3 nanosheets have an irregular flake shape and Ru catalyst is found on the surface of nanosheets with an oxided state. It is also found that the sensor response of WO3 is greatly improved by the loading of Ru. Based on the power-law response of oxygen and TPR results, the sensitization mechanism of Ru is explained. It is proposed that the introduction of Ru promotes the catalytic activity of WO3 and in turn modulates the reaction route of NH3 with oxygen adsorbates on the surface, which inhibit the generation of nitrogen oxides and consequently reduces the competitive adsorption with oxygen during the sensor responses.

The nitrate-nitrite-NO pathway in health and disease

Inorganic nitrate and nitrite from endogenous and dietary sources have emerged as substrates for NO-synthase independent generation of NO and other bioactive nitrogen oxides. Bioactivation of nitrate requires the presence of nitrate reducing bacteria to generate the more reactive nitrite anion. This reaction takes place in the oral cavity where nitrate is actively secreted. Nitrite generates a multitude of nitrogen oxides in the acidic stomach and systemically after absorption. I will here cover the latest development in the field including mechanisms of activation, signaling pathways affected and physiological and therapeutic effects with a focus on the cardiovascular and metabolic systems. This story has an intriguing nutritional aspect considering that nitrate is abundant in our everyday diet.