Wind loads on attached canopies and their effect on the pressure distribution over arch-roof industrial buildings

Arch-roof industrial buildings are very wind sensitive. The current aerodynamic coefficients in wind codes do not contemplate the possibility of existence of canopies attached to the buildings. This paper presents the results of an investigation on the influence exerted by canopies on the static wind actions on arch-roof industrial buildings. Six scale models of these arch-roof buildings were tested, with five types of canopies attached. Three of these canopies were instrumented and the static wind pressures were measured. The tests were done at the boundary layer wind tunnel of the Universidade Federal do Rio Grande do Sul. The results show that the aerodynamic coefficients for the roof are not affected by the canopies, in the case of axial incidence. However, the influence on the pressure distribution is noticeable for wind incidence perpendicular to the main axis of the arch roofs and for other incidences as well. This influence is discussed in the paper. The aerodynamic coefficients for the design of the arch-roofs, with and without the attached canopies are given. Aerodynamic coefficients for design of the canopies are also suggested. Furthermore, the paper discusses the relation between the magnitude of the canopy design forces and the canopy width, as well as the relation between the canopy height location and the height of the building wall. The results were compared with design recommendations from previous work of Jancauskas and Holmes (in: US National Conference on Wind Engineering, Proceedings, Texas Tech University, Lubbock, 1985) and Jancauskas and Eddleston (in: International Conference on Wind Engineering, Fotodruck J. Mainz, Aachen, 1987).     

Evacuation of a Metro Train in an Underground Rail Transportation System: Flow Rate Capacity of Train Exits,Tunnel Walking Speeds and Exit Choice

Including in total 135 participants in the ages 19–69 years (recruited from the general public), an unannounced full-scale field evacuation experiment was performed in the Stockholm underground metro system on the night between October 17 and 18, 2014. The purpose was to collect data on the flow rate of people in train exits during the evacuation of a train in a tunnel and on the walking speed of people when moving long distances on an uneven surface in a tunnel, and to study exit choice and behaviour during an evacuation. Consequently, the experiment involved the evacuation of a rail car (a Bombardier C20 train) in a tunnel as well as the subsequent evacuation of the tunnel itself; the latter meant that the participants either could evacuate to the closest station (~400 m) or to an available emergency exit (~200 m). Among other things, the experiment demonstrated that the averaged flow rates of people in the train exits varied between 0.19 p/s and 0.22 p/s (0.14–0.16 p/m s when considering the train exit width of 1.4 m) and that the averaged walking speeds in the tunnel varied between 1.1 m/s and 1.2 m/s (no smoke present). Furthermore, all 135 participants found and used the available emergency exit, which had been equipped with a technical system consisting of a loudspeaker that broadcasted a combined alarm signal and a pre-recorded voice message.     

Charge transport in grain size tuned CuO nanocrystal films

Journal of Electroceramics - CuO nanocrystal (NC) films of different grain sizes were synthesized through the oxidation of Cu films deposited by controlling the supersaturation in the deposition...     

The Effect of Energy-Supply and Performance Indicators on the Performance of Traction-Resource Management Centers

Russian Electrical Engineering - This paper presents the results of a study of the effect of the characteristics of the traction power-supply system on the indicator of the energy supply of...     

Diagnostics of Multioperation Processes Using Basic Cells of Digital Homogeneous Structures

Russian Electrical Engineering - The cells of homogeneous digital structures designed for multioperation process diagnostics are considered in the form of graphic models. Digital circuits and...     

Development of a thermal scheme for a cogeneration combined-cycle unit with an SVBR-100 reactor

At present, the prospects for development of district heating that can increase the effectiveness of nuclear power stations (NPS), cut down their payback period, and improve protection of the environment against harmful emissions are being examined in the nuclear power industry of Russia. It is noted that the efficiency of nuclear cogeneration power stations (NCPS) is drastically affected by the expenses for heat networks and heat losses during transportation of a heat carrier through them, since NPSs are usually located far away from urban area boundaries as required for radiation safety of the population. The prospects for using cogeneration power units with small or medium power reactors at NPSs, including combined-cycle units and their performance indices, are described. The developed thermal scheme of a cogeneration combined-cycle unit (CCU) with an SBVR-100 nuclear reactor (NCCU) is presented. This NCCU should use a GE 6FA gasturbine unit (GTU) and a steam-turbine unit (STU) with a two-stage district heating plant. Saturated steam from the nuclear reactor is superheated in a heat-recovery steam generator (HRSG) to 560–580°C so that a separator–superheater can be excluded from the thermal cycle of the turbine unit. In addition, supplemental fuel firing in HRSG is examined. NCCU effectiveness indices are given as a function of the ambient air temperature. Results of calculations of the thermal cycle performance under condensing operating conditions indicate that the gross electric efficiency η _{el NCCU} ^gr of = 48% and N _{el NCCU} ^gr = 345 MW can be achieved. This efficiency is at maximum for NCCU with an SVBR-100 reactor. The conclusion is made that the cost of NCCU installed kW should be estimated, and the issue associated with NCCUs siting with reference to urban area boundaries must be solved.     

Simulation of one-sided heating of boiler unit membrane-type water walls

This study describes the results of simulation of the temperature field and the stress-strain state of membrane-type gastight water walls of boiler units using the finite element method. The methods of analytical and standard calculation of one-sided heating of fin-tube water walls by a radiative heat flux are analyzed. The methods and software for input data calculation in the finite-element simulation, including thermoelastic moments in welded panels that result from their one-sided heating, are proposed. The method and software modules are used for water wall simulation using ANSYS. The results of simulation of the temperature field, stress field, deformations and displacement of the membrane-type panel for the boiler furnace water wall using the finite-element method, as well as the results of calculation of the panel tube temperature, stresses and deformations using the known methods, are presented. The comparison of the known experimental results on heating and bending by given moments of membrane-type water walls and numerical simulations is performed. It is demonstrated that numerical results agree with high accuracy with the experimental data. The relative temperature difference does not exceed 1%. The relative difference of the experimental fin mutual turning angle caused by one-sided heating by radiative heat flux and the results obtained in the finite element simulation does not exceed 8.5% for nondisplaced fins and 7% for fins with displacement. The same difference for the theoretical results and the simulation using the finite-element method does not exceed 3% and 7.1%, respectively. The proposed method and software modules for simulation of the temperature field and stress-strain state of the water walls are verified and the feasibility of their application in practical design is proven.     

Test facility for investigation of heat transfer of promising coolants for the nuclear power industry

The results are presented of experimental investigations into liquid metal heat transfer performed by the joint research group consisting of specialist in heat transfer and hydrodynamics from NIU MPEI and JIHT RAS. The program of experiments has been prepared considering the concept of development of the nuclear power industry in Russia. This concept calls for, in addition to extensive application of water-cooled, water-moderated (VVER-type) power reactors and BN-type sodium cooled fast reactors, development of the new generation of BREST-type reactors, fusion power reactors, and thermonuclear neutron sources. The basic coolants for these nuclear power installations will be heavy liquid metals, such as lead and lithium-lead alloy. The team of specialists from NRU MPEI and JIHT RAS commissioned a new RK-3 mercury MHD-test facility. The major components of this test facility are a unique electrical magnet constructed at Budker Nuclear Physics Institute and a pressurized liquid metal circuit. The test facility is designed for investigating upward and downward liquid metal flows in channels of various cross-sections in a transverse magnetic field. A probe procedure will be used for experimental investigation into heat transfer and hydrodynamics as well as for measuring temperature, velocity, and flow parameter fluctuations. It is generally adopted that liquid metals are the best coolants for the Tokamak reactors. However, alternative coolants should be sought for. As an alternative to liquid metal coolants, molten salts, such as fluorides of lithium and beryllium (so-called FLiBes) or fluorides of alkali metals (so-called FLiNaK) doped with uranium fluoride, can be used. That is why the team of specialists from NRU MPEI and JIHT RAS, in parallel with development of a mercury MHD test facility, is designing a test facility for simulating molten salt heat transfer and hydrodynamics. Since development of this test facility requires numerical predictions and verification of numerical codes, all examined configurations of the MHD flow are also investigated numerically.     

Boosting the electrochemical performance of Li-garnet based all-solid-state batteries with Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> electrode: Routes to cheap and large scale ceramic processing

All-solid-state batteries based on fast Li⁺ conducting solid electrolytes such as Li₇La₃Zr₂O₁₂ (LLZO) give perspective on safe, non-inflammable, and temperature tolerant energy storage. Despite the promise, ceramic processing of whole battery assemblies reaching close to theoretical capacities and finding optimal strategies to process large-scale and low cost battery cells remains a challenge. Here, we tackle these issues and report on a solid-state battery cell composed of Li₄Ti₅O₁₂ / c-Li_6.25Al_0.25La₃Zr₂O₁₂ / metallic Li delivering capacities around 70–75 Ah/kg with reversible cycling at a rate of 8 A/kg (for 2.5–1.0 V, 95 °C). A key aspect towards the increase in capacity and Li⁺ transfer at the solid electrolyte-electrode interface is found to be the intimate embedding of grains and their connectivity, which can be implemented by the isostatic pressing of cells during their preparation. We suggest that simple adaption of ceramic processing, such as the applied pressure during processing, strongly alters the electrochemical performance by assuring good grain contacts at the electrolyte-electrode interface. Among the garnet-type all-solid-state ceramic battery assemblies in the field, considerably improved capacities and cycling properties are demonstrated for Li₄Ti₅O₁₂ / c-Li_6.25Al_0.25La₃Zr₂O₁₂ / metallic Li pressed cells, giving new perspectives on cheap ceramic processing and up-scalable garnet-based all-solid-state batteries.     

Peat swamps at Giral lignite field of Barmer basin,Rajasthan, Western India: understanding the evolution through petrological modelling

International Journal of Coal Science & Technology - The lignite samples collected from Giral lignite field of Barmer basin have been subjected to petrological investigation. The data generated...