The paper is devoted to the main results of the development and application of a multilevel approach to mathematical and computer modeling of large-scale pipeline systems. The approach is intended to ...overcome the problems of dimension of such systems, as well as fragmentation of information and methodological support of modeling tasks that are dealt with at different departmental, regional, organizational and temporal levels of decision-making on the control of pipeline system expansion and operation. The principles and experience of the implementation of a computer platform for the automation of customization and use of multilevel information and computational models of pipeline systems of various purposes are characterized. Heating systems are used as an example to set forth the mechanisms for implementing the multilevel approach to calculate and analyze operating conditions in the design, operation and dispatch control. The formalization of the hydraulic planning task is presented as a discrete-continuous optimization problem of large dimension with multiple criteria. A new procedure for hierarchical optimization of hydraulic conditions and new methods to solve the problems of optimization of different hierarchical levels and coordination of solutions are presented. This approach could be useful in calculation of energy systems (heat, gas, water, electricity, etc.).
Aqueous Phase Reforming (APR) has during the recent years emerged as a potent, alternative means of processing raw materials of biological origin to component suitable as chemicals and fuel ...components. In contrary to e.g. steam reforming, aqueous phase reforming bares the promise of lower temperatures in processing which gives rise to potential of reduced energy consumption in the upgrading process itself.
Aqueous phase reforming was studied over Pt/Al2O3 at 225 °C. Stable catalyst performance and high selectivity was observed. Upon a comparison of two ‘bio-alcohols’, bio-ethanol and Sorbitol (a sugar alcohol), the latter one is a better feedstock from overall energy utilization viewpoint but the use of it results in a broad range of products. Interestingly, in the case of sorbitol–ethanol mixtures, an improvement in the hydrogen yield was observed.
The results of measuring the electron temperature and density spatial distributions in plasma of the Globus-M2 tokamak using the Thomson scattering diagnostics are presented. The diagnostics provides ...measurements throughout the entire tokamak discharge, starting from time of gas breakdown. The Thomson scattering data were analyzed in order to determine the positions of the last closed flux surface, the plasma magnetic axis, and the radius of inversion during the saw-tooth oscillations. The results of measurements performed during the internal reconnection of magnetic field lines are presents, as well as the dynamics of spatial distributions of electron temperature, density and pressure during the plasma transition to the H-mode. The results of measuring the electron temperature distribution in the scrape-off layer using the Thomson scattering diagnostics are also presented for distances up to 4 cm outside the last closed flux surface.
Abstract
The work presents the results of the energy confinement study carried out on the compact spherical tokamak Globus-M2 with a toroidal magnetic field as high as 0.8 T. A reproducible and ...stable discharge was obtained with the average plasma density (5–10) × 10
19
m
−3
. Despite the increase in the magnetic field, the neutral beam injection (NBI) led to clear and reproducible transition to the H-mode accompanied by a decrease in the turbulence level at the plasma edge. NBI allowed effectively heat the plasma: electron and ion temperatures in the plasma core exceeded 1 keV. Compared to the previous experiments carried out with a toroidal magnetic field as high as 0.4 T plasma total stored energy was increased by a factor of 4. The main reason or this phenomenon is a strong dependence of the energy confinement time on the toroidal magnetic field in the spherical tokamak. It was experimentally confirmed that such kind of dependence is valid for ST with magnetic field up to 0.8 T. It has also been shown that the enhancement of the energy confinement in Globus-M2 with collisionality decrease is associated with an improvement of both electron and ion thermal insulation.
Laser scanning methods for surface geometry reconstruction have become a common tool in many areas of application due to relative simplicity, high accuracy, and versatility. Nevertheless, scanning of ...glossy or translucent surfaces still poses a problem for these techniques. The present work aims at assessing the applicability of the laser line scanning method for evaluation of the height profile of a waste stream on a conveyor belt, taking into account that the waste stream may contain a large number of semi-transparent objects. In particular, preliminary results of height profile measurements with regard to the laser emission wavelength for polyethylene terephthalate (PET) bottles with various degrees of transparency, common in the municipal solid wastes, are reported in the paper.
Among the peripheral instabilities observed at the Globus-M2 tokamak, two types of edge localized modes (ELMs) are brought into focus: ELMs synchronized and desynchronized with the sawtooth ...oscillations. The desynchronized ELMs appear in regimes that are characterized by high values of pressure in the pedestal,
p
ped
≥ 3 kPa, and they are observed in discharges with the toroidal magnetic field
B
T
> 0.6 T and plasma current
I
P
> 0.3 MA. The desynchronized ELMs belong to the type-III/V with the dominating effect of the peeling mode. The synchronized ELMs were observed in a wider range of discharge parameters, including at
B
T
< 0.6 T and
I
P
< 0.3 MA. Calculations of the stability of the peeling-ballooning (PB) mode showed that at pedestal width ψ
norm
= 0.09 and
p
ped
> 3.5 kPa, destabilization of PB modes is possible without additional influence. Experimental data shows that the microtearing mode plays a dominant role in the pedestal. The microtearing mode does not allow the pedestal at Globus-M2 tokamak to reach the state of the unstable kinetic ballooning mode (KBM), which explains the low predictive power of the EPED model at this tokamak.
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•Urea was used as a template to create anion layers in ET-based charge transfer salts.•New salts ET5MCl4MCl3(u)(u)2, M = Co, Zn (1, 2) and ET2+(u)2H+ZnCl4 (3) formed.•Identical ...resistivity behavior of 1 and 2 suggests the absence of π-d coupling in 1.•Magnetic susceptibility of 1 is defined mainly by cobalt(II) anions, TWeiss = +0.6 K.•At 250-60 K, 1 shows one EPR signal attributed to ET. Co signals are superimposed below.
New compounds (ET)5MIICl4MIICl3(u)(u)2, MII = Co (1), Zn (2) and α-(ET)2(u)2(H)ZnCl4 (3) have been prepared and characterized. Urea (u) was used as a template for creating anionic layers in ET-based layered charge transfer salts, ET = bis(ethylenedithio)tetrathiafulvalene. In the anion layers of 1 and 2, urea molecules form chains, in the channels between which there are chains of tetrahedral anions MIICl42− and MIICl3(u)−, these chains being parallel to the ribbons of ET radical cations from cation layers. In the anion layers of 3, the ZnCl42− anions and the (u)2(H)+ cations alternate in a checkerboard pattern and form hydrogen-bonded chains parallel to the ET stacking direction in cation layers. Electrical transport studies reveals that 1 and 2 behave as metals down to 75 and 65 K, respectively, and 3 is a semiconductor with activation energy of 0.1 eV. Magnetic susceptibility of 1 defined mainly by cobalt(II) anions follows the Curie-Weiss law. The Weiss temperature value (+0.6 K in the 10–300 K range) indicates weak magnetic coupling between the cobalt(II) spins. In the EPR spectrum of 1, one signal attributed to the ET radical cation is detected down to 60 K, and wide signals from cobalt are superimposed below this temperature.
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