112 research outputs found
Recent hydrothermal systems of Kamchatka
Study of the largest manifestations of the recent hydrothermal activity in Uzon-Semyachik, Pauzhetka-Kambalny and other regions in Kamchatka enable us to conclude: in the area of recent volcanism characterized by a general increase of conductive heat flow, some regions can be distinguished with an especially intense geothermal regime specified by an additional supply of heat by deep fluids. Within such anomalies the formation of hydrothermal systems can be observed. Recent hydrothermal systems of Kamchatka are natural hydrodynamic systems belonging to the type of small artesian basins and artesian slopes having porous-bedded, fissure-bedded and more seldom fissure-veined permeability and containing high-temperature underground waters. They are associated with volcano-tectonic grabens and circular depressions filled with a series of tufaceous material of mainly acid composition and two-membered structure. Localization of certain thermal manifestations within the systems is determined by disjunctive tectonics and outflows of thermal waters to the surface. The same factors are responsible for the position of the recharge areas of the systems with infiltration waters forming the main mass of their water reserves. Usual hydrodynamic methods can be used for a quantitative estimation of these reserves. Heat recharge of the systems is realized by the supply of an over-critical fluid. This is confirmed by hydrogeothermal data, similarity of the chemical composition of high temperature hydrothermal water and their thermo-physical parameters. Manifestations of hydrothermal activity do not reveal any connection with recent andesite-basaltic volcanism of Kamchatka; on the contrary, they are associated with the acid volcanism of the Middle and Upper Pleistocene stage of its geological history, testifying to their genetic similarity. Hydrothermal activity is one of the manifestations of the general geothermal activity of the interior. It is closely related, in time and space, to a certain stage of the volcano-plutonic process and tectonic evolution of mobile belts. The perspectives of obtaining heat and electric energy from hydrothermal systems are considered
Process Simulation and Control Optimization of a Blast Furnace Using Classical Thermodynamics Combined to a Direct Search Algorithm
Several numerical approaches have been proposed in the literature to simulate the behavior of modern blast furnaces: finite volume methods, data-mining models, heat and mass balance models, and classical thermodynamic simulations. Despite this, there is actually no efficient method for evaluating quickly optimal operating parameters of a blast furnace as a function of the iron ore composition, which takes into account all potential chemical reactions that could occur in the system. In the current study, we propose a global simulation strategy of a blast furnace, the 5-unit process simulation. It is based on classical thermodynamic calculations coupled to a direct search algorithm to optimize process parameters. These parameters include the minimum required metallurgical coke consumption as well as the optimal blast chemical composition and the total charge that simultaneously satisfy the overall heat and mass balances of the system. Moreover, a Gibbs free energy function for metallurgical coke is parameterized in the current study and used to fine-tune the simulation of the blast furnace. Optimal operating conditions and predicted output stream properties calculated by the proposed thermodynamic simulation strategy are compared with reference data found in the literature and have proven the validity and high precision of this simulation
Measurement of Leading Proton and Neutron Production in Deep Inelastic Scattering at HERA
Deep--inelastic scattering events with a leading baryon have been detected by
the H1 experiment at HERA using a forward proton spectrometer and a forward
neutron calorimeter. Semi--inclusive cross sections have been measured in the
kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T
<= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV,
or a neutron with energy E' >= 160 GeV. The measurements are used to test
production models and factorization hypotheses. A Regge model of leading baryon
production which consists of pion, pomeron and secondary reggeon exchanges
gives an acceptable description of both semi-inclusive cross sections in the
region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading
neutron data are used to estimate for the first time the structure function of
the pion at small Bjorken--x.Comment: 30 pages, 9 figures, 2 tables, submitted to Eur. Phys.
Formation of a Protective Oxide Coating on the Surface of Stainless Steel under Radiation-Oxidative Pretreatment with Gamma Quanta
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