Changes In Gas Concentrations Research Articles

Measuring the fast oxidation kinetics of a manganese oxygen carrier using microfluidized bed thermogravimetric analysis

Oxygen carriers play critical roles in chemical looping combustion. A key task in investigating the oxygen carrier reactivity is to measure the redox kinetics in the fluidization state. However, this is still a challenge because one must perform the redox kinetics measurement in a fluidizing environment in order to simulate the strong mass and heat transfer occurring in a practical fluidized bed reactor. Herein, we report a new method, called the microfluidized bed thermogravimetric analysis (MFB-TGA), to measure the kinetics of the redox reactions, specifically the fast oxidation reaction of a manganese ore oxygen carrier. MFB-TGA is based on a real-time mass measurement of a solid sample inside a fluidized bed. The experimental data measured by MFB-TGA are interpreted with a K-L two-phase fluidized bed model to incorporate the effect of the gas concentration change in the emulsion phase. We conclude that the oxidation kinetics of this manganese ore are much faster than those of other oxygen carriers in the published works. Based on the measured oxidation reaction kinetics, the reaction time required in the air reactor is only 2.3–4 s. Therefore, a new design concept for CLC where the air reactor is operated under a dilute-phase transport regime is put forward. The new design of the air reactor has the potential to reduce cost and avoid the hot pot problem, which is a promising choice for future CLC application. In brief, this MFB-TGA method can be applied to measure the fast gas–solid reaction kinetics of any type of oxygen carriers, and thus contributes to providing reliable redox kinetics for chemical looping combustion.

Spatiotemporal Distributions of the Temperature and Index Gases during the Dynamic Evolution of Coal Spontaneous Combustion

ABSTRACT To study the migration of the high-temperature region and the dynamic changes in the index gas concentration during spontaneous coal combustion and oxidation, we established spatiotemporal distributions of the temperature and index gases during the dynamic evolution of spontaneous coal combustion. The XK-VI coal spontaneous combustion experimental system was used to investigate the migration law of the high-temperature region of loose coal in an air leakage field environment, and gas was then collected and analyzed. The results indicated that the coal temperature showed a stepwise change during the whole heating process. The general trend of the migration changes of the high-temperature points in the test furnace was to move toward the air inlet side and move from the low-oxygen concentration area toward the high-oxygen concentration area. Before the critical temperature, the high-temperature points were approximately 65 cm away from the air inlet. After the critical temperature, the high-temperature points gradually appeared at a distance of 45 cm from the air inlet. When the coal temperature exceeded the dry cracking temperature, the high-temperature points moved down to approximately 8 cm from the air inlet and finally moved to the air supply surface. Through analysis of the gas concentration in the furnace, the gas content varied with the migration of the high-temperature points in the furnace. The oxygen consumption rate and CO and CO2 production rates increased slowly before the dry cracking temperature and increased rapidly after the dry cracking temperature. The gas ratios of CO/CO2, CH4/C2H6, and C2H4/C2H6 changed near the critical temperature, and CO/CO2 and CH4/C2H6 changed from decreasing to rapidly increasing, and C2H4/C2H6 sharply increased from zero.

ТЕРМОДИНАМІКА ТРАНСФОРМАЦІЇ КЕРОГЕНУ ІІ ТИПУ

The article reviews the chemical structure of type II kerogen. The changes that occur with the structure of type II kerogen as it passes through the stages of catagenesis from immature to post-mature are evaluated. Structural models of type II kerogen at different stages of catagenesis are presented: both obtained empirically after studying the structure by physical and chemical methods and the results of modelling by molecular dynamics method. Methods of equilibrium thermodynamics are used to calculate the composition of the kerogen–gas system for crust sections in the range of 1–20 km with a heat flux of 40 to 100 mW/m2. The composition of kerogen/fluid geochemical system is calculated using the E. T. Jaynes formalism. It boils down to determining the optimal distribution of 5 elements (C, H, O, N, S) among the 44 additive constituents of the solid phase (i. e., type II kerogen) and other individual components that are included in the system (CO2, H2O, H2S, NH3, CH4, C2H6, C3H8, i-C4H10, n-C4H10, i-C5H12, neo-C5H12, n-C5H12). Comparison with the experiments showed that the results of the calculations do not contradict the experiments, with study the structure and changes in type II kerogen with increasing degree of catagenesis. In the analysis of changes in the concentrations of water, carbon dioxide and hydrogen sulfide, it is founded that kerogen could be not only a donor of atoms for gas components, but also their acceptor in contact with a high-energy fluid stream. It is shown that the determination of sulfur-containing atomic groups of kerogen by thermodynamic modelling yields gives more reliable results than molecular dynamics methods. Established is that the concept of “methane-graphite death”, which takes place in the state of thermodynamic equilibrium in the transformation of organic matter, is erroneous. The calculation shows that the composition of the kerogen–gas system, in addition to methane and carbon, includes solid-phase heteroatom groups, various additive components of aromatic structures and gases, both organic and inorganic. The distribution of elements between the additive components of kerogen and gases in this system controls the pressure and temperature in a complex way. The nature of changes in hydrocarbon gas concentrations in equilibrium with type II kerogen indicates the presence of an “oil window” in low-warmed zones within 2–4 km depths.

Study on the Optimization of a Gas Drainage Borehole Drainage Horizon Based on the Evolution Characteristics of Mining Fracture

Gas disaster restricts the safety development of coal mine. The technology of high-level borehole gas drainage is an important means to reduce the gas concentration in goaf. In order to determine the best position of the end of gas drainage hole, in this paper, based on the geological conditions of Xinyuan coal mine 31009 working face, a series of numerical simulation is carried out; and through the field test, the dynamic change of gas concentration in different height of borehole is monitored. The results show that: When the working face advances to different distances, there are four characteristic distribution areas in the horizontal direction: the fracture area of the original rock stratum, fracture channel generation and development area, fracture channel mature area and fracture channel closure area. Although the drilling horizon is different, the change of gas concentration in drilling can be divided into four stages: gas stabilization stage, gas initial change stage, gas fluctuation stage and gas re-stabilization stage. The variation of borehole concentration can reflect the evolution characteristics of fracture area. The response time of gas change in different layers is also different. In the gas initial change stage and the gas re-stabilization stage, the low-level borehole first responds. The response of gas change in high-level drilling is a long process, so the effect of high-level drilling is better than that of low-level drilling. For 31009 working face, the best gas drainage layer is 32m, and the field gas drainage has achieved good practical results. This study can provide some guidance for the prevention and control of gas disaster in goaf.

Wi-Fi Enabled IoT Based Smart Greenhouse

In this present state-of-the-art, Internet of Things (IOT) is an emerging technology that is making our world smarter. WiFi enabled greenhouse monitoring is an intelligent system which is based on several sensors that monitor various changes in temperature, gas concentrations, light and soil moisture in the greenhouse. This comes with an added advantage or provision of linking all these sensors to your mobile phones or computers/laptops using Wi-Fi and internet services through the concept of Internet of Things (IoT), so that if there are any fluctuations, you will be notified immediately. This provides convenient control, through manual operations if necessary, of the greenhouse anytime and anywhere as long as the device is connected to the internet. In this an artificial environment is created so that the crops yield more crops per square meter compared to open field cultivation since the micro climatic parameters that determine crop yield are continuously examined and controlled to ensure that an optimum environment is created.

Gas Releasing Mechanism of LLM‐105 Using Two‐Dimensional Correlation Infrared Spectroscopy

AbstractIn this paper, a sealed in‐situ reaction system and infrared spectroscopy (IR) were used to study the gas releasing mechanism of 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) at different temperatures. Three characteristic stages of LLM‐105 during the heating process to 400 °C were detected by the moving‐window two‐dimensional correlation spectroscopy (MW2D). Two‐dimensional correlation infrared spectroscopy (2DCOS) was employed to examine changes of gas concentration in the sealed system at each stage. We found that in the first stage, LLM‐105 first released H2O and NH3. In the second stage, the decomposition is intensified, the explosive molecule first undergoes the decomposition reaction of releasing H2O, and CO2, subsequently chemical reaction producing several nitrogen gases, such as NO, N2O, HCN, NO2 and NH3. In the third stage, the decomposition process mainly releases CO2 and NH3, and the concentrations of HCN and NO2 decreased gradually. 2DCOS proven to be a very sensitive method for detecting thermal decomposition mechanisms and monitoring gas changes in sealed system.

Solving Optimization of a Mine Gas Sensor Layout Based on a Hybrid GA-DBPSO Algorithm

To expand the monitoring range of the coal mine gas monitoring subsystem and achieve the timely early-warning of the local gas transfinite accident, the covering model of sensor was established. It can realize the function of using the least number of gas sensors to monitor the change of gas concentration in the whole mine. The objective function and constraint conditions of the established model were determined. A hybrid GA-DBPSO algorithm combining the genetic algorithm with the discrete binary particle swarm optimization algorithm was proposed to solve the gas sensor location set covering model. This research result was applied to investigate the gas sensor layout of Baoxin Coal Mine in China, and gas sensor layout schemes were obtained under the condition of different gas sensor shortest alarm time. The relationship between the shortest alarm time and the number of additional gas sensor was given, which can provide guidance and reference for the enterprises managers to make decisions on layout scheme of gas sensors.

Modeling Analysis of Gas Reverse Strategy between Symmetric Solid Oxide Fuel Cell Electrodes

Symmetric solid oxide fuel cell (SSOFC) uses the same material as anode and cathode. The problem of electrode carbon deposition and sulfur poisoning can also be alleviated by the gas exchange between the anode and the cathode. The method of gas purging, switching to new gas species, and controlling the molar fraction of fuel and O2 is the main content of this study. In this study, the SSOFC model was established using the finite element method and corrected using experimental data. Through the simulation method, the gas composition and the pressure of the electrode inlet and outlet are changed. The control strategy of SSOFC cathode and anode gas exchange is given. In this paper, the transient process of electrical response and gas concentration change during the gas exchange operation is analyzed to reduce the operation time.

Mathematical Modeling and Programming in Science Education

Using mathematical models to represent aspects of physical reality is an essential activity in science and science education. This contribution discusses four approaches of using computer programming and mathematical models in classroom activities:1) Mathematical models, found in the textbook, are used as a basis for computer programs. Students, when creating useful interactive python programs calculating concentrations or pH-values, experience similar intellectual challenges as in solving traditional text book problems.2) Scratch-animations simulating physical or chemical systems simulation can be specifically designed to check the validity of given mathematical models.3) A computer-related challenge is to design a simulation (like gas diffusion in a closed system with two phases) that might be a basis for discovering a mathematical model (like Henry's law) or just an element of a mathematical model.4) Using sensor technology and a Raspberry Pi, students create a computer program that automatically visualizes the observed system behaviour (like changes in gas concentrations) in order to find a mathematical model.

Recent Decadal Changes in Heat Waves over China: Drivers and Mechanisms

AbstractObservational analysis indicates significant decadal changes in daytime, nighttime, and compound (both daytime and nighttime) heat waves (HWs) over China across the mid-1990s, featuring a rapid increase in frequency, intensity, and spatial extent. The variations of these observed decadal changes are assessed by the comparison between the present day (PD) of 1994–2011 and the early period (EP) of 1964–81. The compound HWs change most remarkably in all three aspects, with frequency averaged over China in the PD tripling that in the EP and intensity and spatial extent nearly doubling. The daytime and nighttime HWs also change significantly in all three aspects. A set of numerical experiments is used to investigate the drivers and physical processes responsible for the decadal changes of the HWs. Results indicate the predominant role of the anthropogenic forcing, including changes in greenhouse gas (GHG) concentrations and anthropogenic aerosol (AA) emissions in the HW decadal changes. The GHG changes have dominant impacts on the three types of HWs, while the AA changes make significant influences on daytime HWs. The GHG changes increase the frequency, intensity, and spatial extent of the three types of HWs over China both directly via the strengthened greenhouse effect and indirectly via land–atmosphere and circulation feedbacks in which GHG-change-induced warming in sea surface temperature plays an important role. The AA changes decrease the frequency and intensity of daytime HWs over Southeastern China through mainly aerosol–radiation interaction, but increase the frequency and intensity of daytime HWs over Northeastern China through AA-change-induced surface–atmosphere feedbacks and dynamical changes related to weakened East Asian summer monsoon.

Greenhouse Gas Concentration and Volcanic Eruptions Controlled the Variability of Terrestrial Carbon Uptake Over the Last Millennium.

The terrestrial net biome production (NBP) is considered as one of the major drivers of interannual variation in atmospheric CO2 levels. However, the determinants of variability in NBP under the background climate (i.e., preindustrial conditions) remain poorly understood, especially on decadal‐to‐centennial timescales. We analyzed 1,000‐year simulations spanning 850‐1,849 from the Community Earth System Model (CESM) and found that the variability in NBP and heterotrophic respiration (RH) were largely driven by fluctuations in the net primary production (NPP) and carbon turnover rates in response to climate variability. On interannual to multidecadal timescales, variability in NBP was dominated by variation in NPP, while variability in RH was driven by variation in turnover rates. However, on centennial timescales (100‐1,000 years), the RH variability became more tightly coupled to that of NPP. The NBP variability on centennial timescales was low, due to the near cancellation of NPP and NPP‐driven RH changes arising from climate internal variability and external forcings: preindustrial greenhouse gases, volcanic eruptions, land use changes, orbital change, and solar activity. Factorial experiments showed that globally on centennial timescales, the forcing of changes in greenhouse gas concentrations were the largest contributor (51%) to variations in both NPP and RH, followed by volcanic eruptions impacting NPP (25%) and RH (31%). Our analysis of the carbon‐cycle suggests that geoengineering solutions by injection of stratospheric aerosols might be ineffective on longer timescales.

Oxygen minimum zone-type biogeochemical cycling in the Cenomanian-Turonian Proto-North Atlantic across Oceanic Anoxic Event 2

Oceanic Anoxic Events (OAEs) in Earth's history are regarded as analogues for current and future ocean deoxygenation, potentially providing information on its pacing and internal dynamics. In order to predict the Earth system's response to changes in greenhouse gas concentrations and radiative forcing, a sound understanding of how biogeochemical cycling differs in modern and ancient marine environments is required. Here, we report proxy records for iron (Fe), sulfur and nitrogen cycling in the Tarfaya upwelling system in the Cretaceous Proto-North Atlantic before, during and after OAE2 (∼93 Ma). We apply a novel quantitative approach to sedimentary Fe speciation, which takes into account the influence of terrigenous weathering and sedimentation as well as authigenic Fe (non-terrigenous, precipitated onsite) rain rates on Fe-based paleo-redox proxies. Generally elevated ratios of reactive Fe (i.e., bound to oxide, carbonate and sulfide minerals) to total Fe (FeHR/FeT) throughout the 5 million year record are attributed to transport-limited chemical weathering under greenhouse climate conditions. Trace metal and nitrogen isotope systematics indicate a step-wise transition from oxic to nitrogenous to euxinic conditions over several million years prior to OAE2. Taking into consideration the low terrigenous sedimentation rates in the Tarfaya Basin, we demonstrate that highly elevated FeHR/FeT from the mid-Cenomanian through OAE2 were generated with a relatively small flux of additional authigenic Fe. Evaluation of mass accumulation rates of reactive Fe in conjunction with the extent of pyritization of reactive Fe reveals that authigenic Fe and sulfide precipitation rates in the Tarfaya Basin were similar to those in modern upwelling systems. Because of a smaller seawater nitrate inventory, however, chemolithoautotrophic sulfide oxidation with nitrate was less efficient in preventing hydrogen sulfide release into the water column. As terrigenous weathering and sediment flux determine how much authigenic Fe is required to generate an anoxic euxinic or ferruginous proxy signature, we emphasize that both have to be taken into account when interpreting Fe-based paleo-redox proxies.

Application of an Array of Metal-Oxide Semiconductor Gas Sensors in an Assistant Personal Robot for Early Gas Leak Detection

This paper proposes the application of a low-cost gas sensor array in an assistant personal robot (APR) in order to extend the capabilities of the mobile robot as an early gas leak detector for safety purposes. The gas sensor array is composed of 16 low-cost metal-oxide (MOX) gas sensors, which are continuously in operation. The mobile robot was modified to keep the gas sensor array always switched on, even in the case of battery recharge. The gas sensor array provides 16 individual gas measurements and one output that is a cumulative summary of all measurements, used as an overall indicator of a gas concentration change. The results of preliminary experiments were used to train a partial least squares discriminant analysis (PLS-DA) classifier with air, ethanol, and acetone as output classes. Then, the mobile robot gas leak detection capabilities were experimentally evaluated in a public facility, by forcing the evaporation of (1) ethanol, (2) acetone, and (3) ethanol and acetone at different locations. The positive results obtained in different operation conditions over the course of one month confirmed the early detection capabilities of the proposed mobile system. For example, the APR was able to detect a gas leak produced inside a closed room from the external corridor due to small leakages under the door induced by the forced ventilation system of the building.

What Formed the North-South Contrasting Pattern of Summer Rainfall Changes over Eastern China?

The south-flood-north-drought pattern of summer rainfall change over eastern China has been attributed to external forcing (greenhouse gas concentration and aerosol emission changes) and a coupled ocean-atmosphere mode (the Pacific Decadal Oscillation; PDO). Here, we investigate the possibility whether the north-south contrasting pattern of summer rainfall change may occur without external forcing and the PDO effect. Analysis of preindustrial and historical climate model simulations and climatological sea surface temperature–forced atmospheric model simulations identified the north-south pattern of summer rainfall changes under constant external forcing and without the PDO signal. This suggests a possible role of atmospheric internal variability. The decadal rainfall change pattern appears as a manifestation of change in the frequency of occurrence of rainfall anomaly distribution from one specific pattern to the other between two neighboring periods. The external forcing and the ocean-atmosphere coupled mode are not necessary conditions for the occurrence of the north-south pattern of summer rainfall changes over eastern China.

RADIOMEASURING GAS CONCENTRATION TRANSDUCER BASED ON TRANSISTOR STRUCTURE WITH NDR FOR THE DIAGNOSIS OF STRAINS OF THE BACTERIUM HELICOBACTER PYLORI

The article discusses a radiomeasuring gas concentration transducer for the diagnosis of strains of the bacterium Helicobacter pylori. One of the promising directions in the construction of gas concentration transducers for respiratory diagnostics is the use of gas concentration frequency transducers based on the reactive properties of transistor structures with negative differential resistance (NDR). This type of transducers allows you to solve the problem of using analog-to-digital converters, because it implements the method of converting "informative signal - frequency", which is one of the best for further processing on a computer. Theoretical and practical studies have shown that using the reactive properties of semiconductor devices and transistor structures in which there is a negative differential resistance, it is possible to significantly increase the sensitivity and accuracy of measuring gas concentration, in particular NH3. The authors proposed and studied a gas concentration measuring transducer, which is built on the basis of a transistor structure with negative differential resistance and a gas-sensitive element to NH3. With a change in gas concentration, the conductivity of the sensitive element changes, which adsorbs NH3 molecules, which in turn changes the active and reactive components of the impedance of the transistors structure. The reactive component of the impedance of the transistors structure is capacitive in nature. This capacitance is part of the total capacitance that occurs at the electrodes of the drain of a double-gate MOS transistor and collector of a bipolar transistor, which together with the inductance L form a resonant oscillatory circuit. A dynamic mathematical model of the frequency transducer of gas concentration by the method of variable states is developed. The dynamic model of the self-generating secondary transducer of gas concentration allows you to determine the value of the frequency of the output signal depending on the change in gas concentration at any time. Analytical expressions of the transformation function and sensitivity equations are obtained. The sensitivity of the developed device for the diagnosis of strains of the bacterium Helicobacter pylori ranges from 2.1 kHz/ppm to 3.4 kHz/ppm.

The Storm Tracks Response to Changes in Atmospheric Greenhouse Gas Concentration at the South of Brazil and Southwest Atlantic Ocean

Here we investigate the ocean-atmosphere coupling and the contribution of the Sea Surface Temperature (SST) variations in: 1) Brazil-Malvinas Confluence (BMC) region, 2) Southwest Atlantic Ocean and 3) Southern Brazil. Numerical simulations of the ECHAM5/MPI-OM coupled ocean-atmosphere model were used to analyze the changes in the seasonal trajectory of the extratropical cyclones, in terms of intensification of physical mechanisms and implications for future scenarios. The numerical experiment for the future scenario considered an atmospheric CO2 concentration of approximately 770 ppm, which represents an increment of more than 350 ppm over the current values recorded by the Mauna Loa reference station. For this scenario, the results indicated a Storm Tracks (ST) displacement of 5° latitude toward south and changes of the meridional transport of sensible heat, close to 50°S. The increase in SST induces ST intensification and consequently an increase in the occurrence of extratropical cyclones. Overall, in the BMC region, we found a change in the pattern of cyclogenetic activity occurrence, with less frequent, but more intense events. On the Southern Brazilian region, the results of this study indicate increases in rainfall during summer months, whereas, a decrease in frequency and an increase in intensity were found for wintertime. We suggest that these changes could impact the climate dynamic of the Brazilian South coast, with a magnitude yet unknown.

Changes in the Distribution of Temperature in a Coal Deposit and the Composition of Gases Emitted during Its Heating and Cooling

This article presents the results of tests conducted on a measuring system for monitoring changes in the distribution of temperature in a coal deposit during the heating and cooling phases, and their correlation with the analysis of the concentration of gases. The tests were conducted on five samples of hard coal collected in deposits mined in Poland. Measurements of the changes in temperature and changes in gas concentration were conducted from the temperature of 35 to 300 °C, for the heating phase, and from 300 to 35 °C, for the cooling phase. The percentage share of coal of given temperatures was calculated. When comparing the percentage share for the same temperature in the hot spot, for the heating and cooling phase, significant differences in the distribution of the given percentages were observed. Changes in gas concentrations during heating and cooling were analyzed and the dynamics of changes in gas concentrations were determined for the coals tested. Changes in the values of fire hazard indices were analyzed. There were significant differences in the concentration of gases and the values of fire hazard indices between the heating and the cooling phase. The application of different criteria to assess coal during heating and cooling was proposed.

Environmental record of layers of bubbles in natural pond ice

ABSTRACTAutonomous temperature data loggers were used to measure the temperature profile within a growing ice cover and in the water below. The ice formed under natural conditions over the pond. We observed the presence of distinct layers of gas bubbles throughout the ice thickness. Temperature measurements allowed us to determine growth rates (μm s−1) and cooling rates (°C s−1) of the ice and demonstrated that these bubble layers formed during the peak ice growth rates from 0.58 to 0.92 µm s−1. The growth rates, leading to the formation of layers of bubbles, were more than an order of magnitude lower than for bubbles produced in controlled laboratory conditions (from 3 to 80 µm s−1). This observation introduces the possibility that solid impurities play a role in natural waters and that they must lower the limit of growth rates required for bubble occurrence. Data revealed a decrease in ice growth rates while cooling rates increased. We interpret this observation as an effect of the heat flux from the water to the ice (8.34–34.11 W m−2), and of gas concentration changes in the water below. Calculations of the ice thickness using traditional methods showed the necessity to include the heat flux from the water to the ice and the effect of gas bubbles within the ice and near the ice–water interface.

A study on capillary actions of power-law fluids in porous fibrous materials via W-M function

The study of fluid diffusion is an important aspect of heat and mass transfer of the porous fibrous materials. This work established a fractal model for the diffusion of power-law fluids in porous fibrous materials by considering the pore size distribution and the tortuosity of the capillary. Adopting the Darcy’s law and the Hagen–Poiseuille’s law, the diffusion coefficient of power-law fluids is derived as a function of the tortuosity fractal dimension, the pore size fractal dimension and the flow behavior index, in which the phase transition and the adsorption effect of fiber as well as the influence of gas diffusion and temperature change are taken into consideration. And the Weierstrass–Mandelbrot (W-M) function is applied to manifest the detailed fractal characters of the pores. Focusing on an analytical expression of the diffusion of power-law fluids in porous fibrous materials, the changes of liquid volume fraction, gas concentration and temperature distribution subjected to the specification initial and boundary conditions are simulated numerically. The test of this approach on the height of fluids when the bottom of cotton fabrics is immersed in the water display the clear diffusion of fluid in fiber. Our preliminary results indicate the important roles that the porosity and flow behavior index play in the fluids transfer in the porous fibrous materials: the fluids with lower power law index rise higher heights and diffuse more rapidly, meanwhile, the height increases with the porosity.

Soft computing techniques in prediction gas sensor based 2D material

Abstract Two-dimensional materials may be the key to unlock the next technological advancement. There have been many other two-dimensional materials discovered after the discovery of graphene, all with their own unique and interesting properties. One type of two-dimensional materials that were discovered has attracted quite a bit of attention, Phosphorene. Phosphorene is a natural semiconductor with a variable band gap and similar structure to carbon-based graphene. The Field Effect Transistor (FET) structure is employed in this project, where phosphorene has been proposed as the channel material between drain and source. An analytical model is developed assuming that gate voltage variations are proportional to nitrogen dioxide (NO2) gas concentration changes. Furthermore, to obtain other models for the current-voltage(I V) characteristic, Artificial Neural Network (ANN) and Classification and Regression Trees (CART) algorithms have been employed. Finally, the developed models were compared with the data extracted from experimental work by A. Abbas, which show satisfactory agreement and validity of the proposed models.