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This study aims to investigate the potential of the decorated boron nitride nanocage (BNNc) with transition metals for capturing carbon monoxide (CO) as a toxic gas in the air.

BNNc was modeled in the presence of doping atoms of titanium (Ti), vanadium (V), chromium (Cr), cobalt (Co), copper (Cu) and zinc (Zn) which can increase the gas sensing ability of BNNc. In this research, the calculations have been accomplished by CAM–B3LYP–D3/EPR–3, LANL2DZ level of theory. The trapping of CO molecules by (Ti, V, Cr, Co, Cu, Zn)–BNNc has been successfully incorporated because of binding formation consisting of C → Ti, C → V, C → Cr, C → Co, C → Cu, C → Zn.

Nuclear quadrupole resonance data has indicated that Cu-doped or Co-doped on pristine BNNc has high fluctuations between Bader charge versus electric potential, which can be appropriate options with the highest tendency for electron accepting in the gas adsorption process. Furthermore, nuclear magnetic resonance spectroscopy has explored that the yield of electron accepting for doping atoms on the (Ti, V, Cr, Co, Cu, Zn)–BNNc in CO molecules adsorption can be ordered as follows: Cu > Co >> Cr > Zn ˜ V> Ti that exhibits the strength of the covalent bond between Ti, V, Cr, Co, Cu, Zn and CO. In fact, the adsorption of CO gas molecules can introduce spin polarization on the (Ti, V, Cr, Co, Cu, Zn)–BNNc which specifies that these surfaces may be used as magnetic-scavenging surface as a gas detector. Gibbs free energy based on IR spectroscopy for adsorption of CO molecules adsorption on the (Ti, V, Cr, Co, Cu, Zn)–BNNc have exhibited that for a given number of carbon donor sites in CO, the stabilities of complexes owing to doping atoms of Ti, V, Cr, Co, Cu, Zn can be considered as: CO →Cu–BNNc >> CO → Co–BNNc > CO → Cr–BNNc > CO → V–BNNc > CO → Zn–BNNc > CO → Ti–BNNc.

This study by using materials modeling approaches and decorating of nanomaterials with transition metals is supposed to introduce new efficient nanosensors in applications for selective sensing of carbon monoxide.

A domain‐adaptive technique which maps the unknown, time‐dependent, curvilinear geometry of annular liquid jets into a unit square is used to determine the steady state mass absorption rate and the collapse of annular liquid jets as functions of the Froude, Peclet and Weber numbers, nozzle exit angle, initial pressure and temperature of the gas enclosed by the liquid, gas concentration at the nozzle exit, ratio of solubilities at the inner and outer interfaces of the annular jet, pressure of the gas surrounding the liquid, and annular jet's thickness‐to‐radius ratio at the nozzle exit. The domain‐adaptive technique yields a system of non‐linearly coupled integrodifferential equations for the fluid dynamics of and the gas concentration in the annular jet, and an ordinary differential equation for the time‐dependent convergence length. An iterative, block‐bidiagonal technique is used to solve the fluid dynamics equations, while the gas concentration equation is solved by means of a line Gauss‐Seidel method. It is shown that the jet's collapse rate increases as the Weber number, nozzle exit angle, temperature of the gas enclosed by the annular jet, and pressure of the gas surrounding the jet are increased, but decreases as the Froude and Peclet numbers and annular jet's thickness‐to‐radius ratio at the nozzle exit are increased. It is also shown that, if the product of the inner‐to‐outer surface solubility ratio and the initial pressure ratio is smaller than one, mass is absorbed at the outer surface of the annular jet, and the mass and volume of the gas enclosed by the jet increase with time.

This paper aims to provide details of the major optical gas sensing techniques and their applications.

Following an introduction, this paper first identifies the major gas sensing technologies and provides an overview of optical sensing techniques. The sources and impact of the gases most frequently sensed by optical methods are listed. Three non-absorption-based and nine absorption-based methods and their main applications are then described in detail. Brief concluding comments are drawn.

All manner of optical gas sensing techniques have been commercialised and while the majority are absorption-based, several other methods also play a significant role. Some optical gas sensors offer advanced capabilities such as remote monitoring, the creation of 2D and 3D distribution maps, detection of parts per trillion levels and even the visualisation of gases in real time. They play a vital role in protecting workers from hazardous gases, controlling and minimising air pollution and monitoring the atmospheric environment, as well as being used in the food, medical, process, power generation and other industries.

This paper provides a detailed insight into optical gas sensing techniques and their uses.

Looks at models constructed for the gas industry domestic, central heating, cooling and industrial markets. Shows how these models can be used to permit the rapid assessment of marketing targets for appliance sales and price levels against gas supply constraints. Concludes that although these models do not provide instant solutions to the marketing problems of the gas industry they do help to organize available data in a more efficient way.

The purpose of this paper is to model the trend of natural gas supply and demand in China in different circumstances from 1990 to 2050.

The related factors were selected from references and classified into three categories such as endogenous, exogenous, and excluded factors. The three sub‐models of supply, demand and their interconnection were built and integrated. The impacts of natural gas resources, the investment of gas industry and the energy structure over natural gas supply and demand were analyzed based on scenario analysis.

The impact of energy structure in China is more evident compared to natural gas resources and the investment level.

Import and transportation of natural gas will have growing impacts on the supply and demand in China when the model is applied.

A very useful method to analyze the equilibrium of natural gas supply and demand.

The paper presents a new prediction model of natural gas supply and demand in system dynamics. The paper is aimed at the researchers and decision makers in energy industries, especially in the fields of energy prices.

This paper aims to evaluate nine types of electrical energy generation options with regard to seven criteria. The analytic hierarchy process (AHP) was used to perform the evaluation. The TOPSIS method was used to evaluate the best generation technology.

The options that were evaluated are the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine. The criteria used for the evaluation are CO₂ emissions, NOX emissions, efficiency, capital cost, operation and maintenance costs, service life and produced electricity cost.

The results drawn from the analysis in technology wise are as follows: natural gas fuelled solid oxide fuel cells>natural gas combined cycle>natural gas fuelled phosphoric acid fuel cells>natural gas internal combustion engine>hydrogen fuelled solid oxide fuel cells>hydrogen internal combustion engines>hydrogen combustion turbines>hydrogen fuelled phosphoric acid fuel cells> and natural gas turbine. It shows that the natural gas fuelled solid oxide fuel cells are the best technology available among all the available technology considering the seven criteria such as service life, electricity cost, O&M costs, capital cost, NOX emissions, CO₂ emissions and efficiency of the plant.

The most dominant electricity generation technology proved to be the natural gas fuelled solid oxide fuel cells which ranked in the first place among nine alternatives. The research is helpful to evaluate the different alternatives.

The research is helpful to evaluate the different alternatives and can be extended in all the spares of technologies.

The research was the original one. Nine energy generation options were evaluated with regard to seven criteria. The energy generation options were the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine. The criteria used for the evaluation were efficiency, CO₂ emissions, NOX emissions, capital cost, O&M costs, electricity cost and service life.

Summarizes some of the most commonly used gas sensors and describes how each one works. Covers solid state gas sensors; aqueous electrochemical gas sensors; paramagnetic gas sensors, photometric gas sensors; thermal conductivity gas sensors and fibre‐optic gas sensors.

The purpose of this paper is to develop the micro-electro-mechanical systems (MEMS) technology has created the conditions for the study of microfluidic technology. Microfluidic technology has become a very large branch in the MEMS field over the past decade. For aerostatic thrust bearing, the micro-fluidic gas flow in a small-scale gas film between two parallel plates is the subject of many studies. Because of the thin gas in the film, velocity slip occurs at the interface, which causes the gas flow pattern to change in the lubricating film. So, it is important to clarify the mechanism and pressure characteristics in thin firm gas flow.

First, a new assumption and corresponding models for the flow regime were established by theoretical analysis. Second, computational simulations about pressure distribution and velocity were given by a large-scale atomic/molecular massively parallel simulator (LAMMPS). Third, comparison of the results of LAMMPS simulation and direct simulation Monte Carlo calculation were made to verify the reliability of above results.

The gas flow mechanism and corresponding regulations are significantly different from traditional pneumo dynamics, which can be described by Navier–Stokes equations accurately. Combining theatrical study and computational results, the stratification theory of the gas film was verified. The research shows that when the gas flow rate increased, the pressure of the gas film decreased, the thickness of the continuous flow layer increased, the thickness of the thin layer decreased and the layered pressure in the gas film disappeared. In this case, velocity slippage could be ignored.

First, this paper established an analytical model of the gas film support and proposed a film stratification theory. The gas film was divided into the near wall layer, the thin layer and the continuous layer, which was proved by the calculation of LAMMPS flow simulation. The velocity slip boundary conditions theory is feasible. Second, the gas film size of the flat plate is at the micron level, which cannot be observed in its flow regimen, only determined by calculation and simulation. This paper proposes a new model and a new tool to analyze gas flow in gas films.

In this paper, we theoretically examine the optimal hedge strategy for a natural gas company. The use of natural gas derivatives to minimize consumers' per unit cost of natural gas consumed, or to minimize the upside risk associated with extreme bills would be the strategy being considered by local distribution companies (LDCs) and regulators. The objective is, therefore, to stabilize the summer and the winter months' natural gas prices as well as to improve the level of customers' welfare. In general, during the summer injection period, April through October, utility companies purchase a certain amount of natural gas and keep in storage facilities and, hence, during the winter withdrawal months, November through March, utility companies supply natural gas at a predetermined minimal fuel cost rate to residential and commercial customers. Therefore, to manage these conflicts of interests efficiently should natural gas companies be supported by accurate forecast of the natural gas price for the winter months. Otherwise, natural gas companies will trade natural gas derivatives in order to reduce costs charged to customers. The results show that customers benefit from the use of natural gas derivatives. If the natural gas market is deregulated, the typical risk-return trade off shows that natural gas derivatives would provide the most efficient tools for utility companies to minimize the natural gas price volatilities.

In the first part of the paper, which outlines the laboratory and field investigations on corrosion by flue gases from solid fuel combustion carried out by the British Coal Utilisation Research Association, the effects of different flue gas constituents on corrosion phenomena are discussed. Laboratory studies of the effects of fuel type and method of combustion on the sulphuric acid content of combustion gases are described. The second part presents the results of measurements of the condensation characteristics of flue gases from water‐tube boilers in power stations and from various industrial boilers and furnaces; investigations into the use of additives are described briefly. The final section is concerned with some theoretical considerations of effects of fuel type, burning rate, etc., on the amounts of sulphuric acid likely to be present in the combustion products from domestic appliances.