Features of processes in a microwave discharge in water vapor

A zero-dimensional steady-state simulation of microwave discharge in water vapor at atmos-pheric and reduced pressures and a constant gas temperature has been carried out. A model of a continuous stirring reactor is used. A joint solution of the balance equations for neutral and charged plasma components, the Boltzmann equation for plasma electrons, and the equation for the stationary distribution of the microwave field in a volume filled with plasma is carried out. The dependences of various parameters of thedischarge (the magnitude of the microwave field, the concentrations of all components) on the input specific power WVare obtained. It is shown that at reduced pressure the magnitude of the microwave field in the plasma is signifi-cantly lower, and the electron concentration is higher than at atmospheric pressure at the same applied specific power. At atmospheric pressure the water plasma is electronegative, and quasi-neutrality is maintained by the negative OH-ion in the range of the considered WV values. Transition from electronegative to electropositive plasma occurs at pressure of 30 Torr and ap-plied specific power of 60–70 kW/cm3

THE INFLUENCE OF PRESSURE AND TEMPERATURE ON THE COMPRESSIBILITY FACTOR

The natural gas compressibility factor indicates the compression and expansion characteristics of natural gas under different conditions. It is a thermodynamic property used to take into account the deviation of the behaviour of real natural gases from that of an ideal gas. Compressibility factor, Z, values of natural gases are necessary for most petroleum gas engineering calculations. In this study, a comparison between five different calculation methods is presented to determine this critical parameter for the same natural gas at different conditions (pressure and temperature), using Canadian Association of Petroleum Producers, Azizi, Behbahani and Isazadeh, Dranchuk- Purvis- Robinson, Dranchuk-Abu-Kassem and Standing- Katz methods. The correlations are based on the equation of state are often implicit because they require iteration. Many correlations have been derived to enhance simplicity; however, no correlation has been developed for the entire range of pseudo-reduced pressures and temperatures. Azizi, Behbahani and Isazadeh’s method was found to have the biggest error as a result obtained for T=20° C, and p=20 bar is no longer in the field of applicability.

К 125-летию со дня рождения лауреата Нобелевской премии академика Николая Николаевича Семенова Цепной механизм воздействия добавок дихлордифторметана на горение водорода и метана в кислороде и воздухе

The effect of difluorodichloromethane additives on spark initiated combustion of hydrogen and methane in air and oxygen at atmospheric and reduced pressures was investigated. It has been found that the ignition concentration limit of the premixed hydrogen-air mixture in the presence of difluorodichloromethane at 1 atm exceeds 10%, while it has been shown for the first time that the ignition limit of the premixed methane-air mixture is 1% of difluorodichloromethane, which is thereby the most effective methane combustion inhibitor. This also means that the active combustion centers of hydrogen and methane, which determine the development of combustion, have a different chemical nature. Thus, the reaction including a difluorodichloromethane molecule resulting in the formation of HF (v = 2.3) during methane combustion should include a step involving the active methane combustion intermediate. Using hyperspectrometers of the visible and near-infrared ranges in the products of the oxidation reactions of hydrogen and methane in the presence of difluorodichloromethane, vibrationally excited HF molecules (v = 2.3) were first discovered. For the first time, it was found that HF molecules (v = 3) during methane combustion are formed at the moment when the maximum rate of chemical conversion is achieved, that is, reactions involving inhibitor molecules compete with the process of development of reaction chains. Keywords: chain burning, inhibition, methane, hydrogen, dichlorodifluoromethane, hyperspectrometer, high-speed color filming, radicals, excited particles.

PHYSICAL MODEL INVESTIGATION OF PARCEL SCALE MANGROVE EFFECTS ON FLOW HYDRODYNAMICS AND PRESSURES AND LOADS IN THE BUILT ENVIRONMENT

Rising seas, tropical cyclones, and tsunamis threaten increasingly populated coastal areas, leaving coastal communities searching for sustainable, resilient adaptation solutions to mitigate the impacts of chronic and acute coastal flood hazards. This work specifically investigates parcel-scale effects of the Rhizophora mangle (red mangrove) species during extreme wave and/or storm surge conditions. We constructed 100 physical models of the Rhizophora species' trunk-prop root system on a 1:16 scale, and conducted tests in Oregon State University's Directional Wave Basin to measure the effects of mangroves of varying cross-shore thickness on water surface elevation, water velocities, and load reduction on idealized inland structural elements. The presence of mangroves affected hydrodynamic conditions near the mangroves and reduced pressures and forces on inland structures.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/XjtCmHYvgVQ