Form Of Flat Plate Research Articles

Impact of Jet Fires on Steel Structures: Application of Passive Fire Protection Materials

Jet fires are the second most common fire scenario after spill fires. This type of fire is characteristic of gas and gas–oil fires occurring on oil platforms and gas production and processing plants. The consequences of such fires are characterized by high material damage; this is associated with extensive networks of technological communications, since there is a high density of technological facilities and installations in the territory where these fires occur. At such facilities, there is a large number of steel structures, which under the action of high temperature quickly lose their strength and deform. To protect steel structures in the oil and gas industry, fire protection is used, which consists of different types: boards in the form of flat plates, plasters, and epoxy paints. This paper compares three types of fire protection materials for steel structures under jet fire: board fireproofing, plaster composition, and epoxy coating. When comparing the efficiency in jet fire, cement boards were found to be the best. However, despite the better fire protection efficiency, their low application is expected due to their massiveness and the high cost of such protection and the difficulty of installation. Nevertheless, the development of fire depends on the place of its origin, the size of the initial fire zone, and the stability and massiveness of the metal elements of the vessel structure or the structure of the boards on which the equipment can be placed. Therefore, it is necessary to take these factors into account when selecting fire protection and to apply it depending on the required fire resistance limits of structures, which should be determined depending on the fire development scenarios.

Lnvestigation of the Effect of a Mechanical Stress Concentrator on the Processes of Occurrence and Development of Cracks in Structural Elements of Aviation Equipment

The purpose of the research is investigation of the patterns of crack development in structural elements of aviation equipment from a stress concentrator under the influence of a force stretching along the main axis, symmetrical alternating loads (vibrations) and combined effects in order to determine the criticality of operation of aircraft products with crack-type defects, substantiation or refutation of the need for research and operation of the processes of development of stress-strain states preceding the occurrence of a crack, in systems and complexes of periodic, preflight and operational control of the technical condition of aircraft products.Methods. Еxperimental study of the patterns of crack development from a stress concentrator in structural elements of two form factors: a cylindrical sample (GOSТ 25347-82) simulating a stringer or a load-bearing structural beam, and a plate sample (GOSТ 1497-84), simulating an aircraft skin element. Cylindrical samples were subjected to deformation caused by the kinetics of rotation, plate samples were subjected to uniaxial tensile stress and the effects of alternating loads (vibrations) individually and in combination.Results. Тhe patterns of near-surface and deep crack development, their relationship with the frequency of application of symmetric alternating loads, have been studied. Еxpressions are established for the approximate engineering calculation of the material endurance limit, fracture surface area and constant endurance with an approximation accuracy Proceedings of the Southwest State University. Series: Control, Computer Engineering, of about 0.8. For samples in the form of flat plates, a stress-strain diagram is constructed, clearly illustrating the decrease in the endurance of the material to the effects of combined loads in relation to the effects of static tensile stresses only. Тhe approximate number of residual cycles before the structural element is destroyed is estimated, taking into account the amplitude-frequency parameters of the acting vibration in the presence of a crack in the sample. Тhe estimation method using the load intensity coefficient and mathematical expressions for its calculation is given.Conclusion. /t is concluded that it is necessary to analyze the dynamics of the development of stress-strain states (fatigue) of the material as states preceding the appearance of cracks in order to carry out sufficient control of the technical condition of structural elements of aircraft products.

Acoustical Efficiency and Physico-Mechanical Characteristics Study for New Composite Material: Ethylene Vinyl Acetate and Wood Sawdust

Developing neoteric composite materials (CM) that improve the acoustic efficiency and mechanical properties become the target of many scientists in the last decade. This paper presents research on developing new CMs using Ethylene Vinyl Acetate (EVA) and sawdust (SD) of different weight concentrations which can be help to improve the acoustic and mechanical properties of the EVA polymer materials. Prototypes of EVA composite in form of flat plates with different weight concentrations of sawdust namely; 0, 2.5, 5, 10, 20 and 30% were produced. One of the interesting applications of this new CMs is to use it as a floor covering in buildings and manufactures. The acoustic efficiency parameters namely, impact noise reduction and sound absorption are experimentally studied. The obtained results articulate that covering floors with the designed composite material of EVA/SD as filler can decrease ISR up to 14 dB. Also, it gives peak sound absorption coefficient about 0.6 for 30 % of SD at mid-frequency band. The greatest proportion of SD aggregate EVA does not entail a higher acoustic performance. The tensile strength of the composite increases to 15.5% when the SD content is 5% and the tensile strength drops with increase the SD content up to 30%. Therefore, SD may be utilized as filler and consolidation in the EVA matrix, which will save expenses and assist the environment.

Experimental determination of fragment dynamics of refractory non-metallic silicate material under high-velocity impact

The individual velocity of rupture fragments after impact is necessary to evaluate how dangerous they are after dispersion. The aim of the study is to experimentally determine the velocity of rupture fragments upon impact on a refractory non-metallic silicate material (potassium fluorophlogopite). The targets made from potassium fluorophlogopite were shaped in the form of flat plates with a size of 280x160x15 mm. A steel ball with a diameter of 23 mm was used as a projectile. Four impact experiments were performed with the following parameters: ball speed of 230 m/s and collision angle of 90°; ball speed of 120 m/s and collision angle of 90°; ball speed of 230 m/s and collision angle of 30°; ball speed of 120 m/s and collision angle of 30°. The velocity of the rupture fragments was determined through video recording obtained using a high-speed Photron Fastcam SA5 camera. The video was processed by analyzing frame-by-frame images using the ImageJ-FiJi. The velocities of individual rupture fragments upon impact on a refractory non-metallic silicate material are experimentally determined using the example of potassium fluorophlogopite. It is established that the nature of the change in the fragment velocity relative to time corresponds to a hyperbolic function and depends on the kinetic energy of the fragments. A coefficient for calculating the change in the velocity of rupture fragments of potassium fluorophlogopite relative to time is proposed.

The Redescription of Eumicrotremus brashnikowi with Remarks on Validity of E. phrynoides (Cyclopteridae, Cottoidei)

The second specimen of Eumicrotremus brashnikowi was found in collection materials of ZIN RAS. The species was placed in the genus Eumicrotremus on the basis of the following diagnostic characters: bone plaques spread all over head and body, including caudal peduncle; two pores in the infraorbital canal of the seismosensory system; pores of the seismosensory system are situated on the ends of long skin tubules on the chin and the lower part of a gill cover. The validity of E. brashnikowi is confirmed by the presence of bone plaques in the form of flat plates covered with very thin and short bone spines forming the rosette. The similar structure of bone plaques was not revealed in juveniles and adult specimens of other species of the genus Eumicrotremus. The redescription of E. brashnikowi is carried out. The considerable similarity of the external skeleton structure of E. brashnikowi and E. phrynoidesis is confirmed. The synonymy of E. phrynoidesis and E. asperrimus is not supported.

Experimental studies into the dependences of the axial lead coolant pump performance on the impeller cascade parameters

The paper presents results of experimental studies into the dependences of the axial lead coolant pump performance (delivery, head, efficiency) on the impeller cascade parameters, including the number of blades, the cascade blade angle and the cascade solidity. The studies were conducted as applied to conditions of small and medium sized plants based on lead cooled fast neutron reactors with horizontal steam generators. The designs of such plants are now in the process of elaboration at Nizhny Novgorod State Technical University (NNSTU). The studies were conducted at NNSTU's FT-4 test facility at a lead coolant temperature of 440–500°C. In the process of investigations, the number of blades in the form of flat plates was 3, 4, 6 and 8, the cascade blade angle was in a range of 9–43°, and the cascade solidity (0.6–1.2) was changed by changing the blade section chord length. The shaft speed of the NNSTU's NSO-01 pump, onto which changeable impellers were installed, was changed in steps of 100 rev/min in an interval of 600–1100 rev/min. The blade diameter was about 200mm, and the maximum lead coolant flow rate in the course of the tests reached ∼2000t/h. The performance of 27 impellers was investigated. It is recommended that the investigation results should be used in design of axial HLMC pumps.

Reference Materials for Fluorescence Based on Inorganic Glass

Reference materials (RM) for relative spectral correction of emission spectra and day-to-day sensitivity monitoring of spectrofluorimeters were developed. The 2 kinds of inorganic glass were used as RM material – custom developed Cu+ –ion doped phosphate glass and colored optical glass SZS-17 (blue-green). RM can be either cuvette-shaped or in the form of flat plate and installed in sample compartment of the instrument. Flat plate geometry allows to minimize the dependency of RM fluorescence intensity from the characteristics of instrument's optical circuit due to inner filter effect.

Coupling between friction physical mechanisms and transient thermal phenomena involved in pad–disc contact during railway braking

During railway braking, friction dissipates high energy, leading to transient and localized thermal phenomena such as hot bands and hot spots. These thermal phenomena interact with third-body flows and friction mechanisms activated in the contact. To provide information on the transient character of these physical mechanisms, severe stop-braking conditions are reproduced on a specially designed braking tribometer. Thermal phenomena observed by infrared thermography on the disc-track are characterised and correlated to the evolution of the friction coefficient. In view to studying the coupling between thermal phenomena and friction mechanisms, rubbing surfaces are observed and analysed at typical stages of braking in correlation with the corresponding disc-track thermograms. The results show how third-body flows, resulting from the waviness distortion of the disc, feed the contact and lead to the formation of the third-body in the form of flat plates that stabilize the friction coefficient.

Advances of thin shell finite elements and some applications—version I

A first attempt is made to review the advances of the formulations for thin shell finite elements in the form of flat plates, axisymmetrical shells and curved shells. The Discrete Kirchhoff Theory shell elements and the degenerated shell elements are discussed. Experiences in shear and membrane lockings are elaborated. The survey is further illustrated with some extensions and applications to cases such as static and dynamic responses, static and dynamic bucklings, laminated composites, random loadings and random structural and material properties. In all cases, studies of the effects of geometric and material nonlinearities are discussed.

Intergranular corrosion of welds in type 405 stainless steel

A low chromium ferritic stainless steel (Type 405) with different heat treatments and weld configurations, has been investigated for susceptibility to intergranular corrosion by chemical and electrochemical potentiodynamic reactivation (EPR) tests, and the results were evaluated by weight losses, dye penetration, metallographic techniques, and the ratio of the reactivating and activating currents. Welds are susceptible to attack, particularly in the heat-affected zone. Applied stress in a U-bend increases significantly the attack on welds, and annealing eliminates the effects of stress. Results on the susceptibility of unwelded specimens in the form of flat plates and U-bends after various heat treatments are also presented and discussed.

Crystallization of one of the chicken pepinogens and its derived pepsin.

Dodecahedral crystals of chicken pepsinogen have been prepared, one perfect cystal having the dimensions 0.090mm x 0.086mm x 0.009mm. The derived pepsin crystakkized in the form of flat plates, often with one rounded end. The dimensions of one such crystal wer 0.076mm x 0.043mm. Both types of protein crystals showed full enzymic or potential enzymic activity.

A laser scan technique for electronic materials surface evaluation

A technique utilizing a scanning laser beam has been implemented to examine the surfaces of materials that are used in the form of flat plates or thin deposited films in the field of microelectronics. Unwanted holes in opaque films deposited onto transparent substrates can be detected by sensing the light transmitted through the holes or defects on a reflective surface can be detected by virtue of their light scattering properties.

Anomalous Skin Effect in Tin and Indium

The normal-state reactive and resistive skin depths of very pure polycrystalline tin and indium have been measured as a function of frequency for frequencies between 7 and 20 000 cps. Measurements were made at liquid-helium temperatures, using specimens in the form of flat plates with a thickness of 1 mm. The free-electron anomalous-skin-effect theory of Reuter and Sondheimer was used to extrapolate the data to infinite frequency, and thus to obtain skin depths appropriate to the extreme anomalous limit. Analysis of the data based on the free-electron model and assuming diffuse electron scattering at the metal surfaces yields the values ${(\frac{\ensuremath{\sigma}}{l})}_{\mathrm{Sn}}=(6.9\ifmmode\pm\else\textpm\fi{}1.5)\ifmmode\times\else\texttimes\fi{}{10}^{10}$ ${\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ and ${(\frac{\ensuremath{\sigma}}{l})}_{\mathrm{In}}=(9.0\ifmmode\pm\else\textpm\fi{}1.6)\ifmmode\times\else\texttimes\fi{}{10}^{10}$ ${\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}$ ${\mathrm{cm}}^{\ensuremath{-}2}$. The skin depths are estimated to deviate from their anomalous limits by approximately 2% at a frequency of 1 Mc/sec.

Kinetics of the aluminum‐chlorine reaction

AbstractThe reaction between aluminum, in the form of flat plates, and chlorine was investigated in a flow system at temperatures from 500° to 650°F. Gaseous aluminum chloride was the reaction product at these temperatures. At 500°F. the reaction proceeded by pitting, and the rate appeared to be chemically controlled. The reaction mechanism changed at higher temperatures to give a smooth reacted surface, and the reaction rate was found to be dependent upon both mass transport and kinetic parameters. The method proposed by Rosner for calculating mass transport‐dependent reaction rates was found to correlate both average and local rate data and was used to obtain estimates of the kinetic parameters for the heterogeneous surface reaction.

The dependence of nuclear magnetic resonance absorption in metals on specimen shape and size

Calculations have been made of the effective distorsion and shift of nuclear resonance lines in metals and alloys due to eddy currents. Expressions have been obtained appropriate to specimens in the form of flat plates, cylinders and spheres, and covering the whole range of the relevant parameters.

VIII. Note on the Artificial Formation of Pyrolusite

In a paper read before the Chemical Society I gave a detailed account of a curious reaction of Manganese salts, and showed that Manganese dioxide resembling pyrolusite could be obtained by the reaction. I have since made many samples, and have obtained nodules so like the natural mineral, that I thought that an account of the method might have some interest for mineralogists. When manganous nitrate is dissolved in strong nitric acid and warmed, and a few chips of potassic chlorate added, there is precipitated in the liquid black oxide of manganese in the form of flat plates which, when very thin, are of a beautiful purple, but when thicker are of a red colour. The whole of the manganese is precipitated in this form, but when the strength of the acid and the temperature are made to vary, the distribution of the plates may be changed.