scholarly journals Determination of distribution of heat-conducting material concentration in protective layer of thermal protection system panel

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1025-1034
Author(s):  
Lukasz Brodzik ◽  
Andrzej Frackowiak
Keyword(s):  
Thermal Protection ◽  
Protective Layer ◽  
Heat Conducting ◽  
Conducting Material ◽  
Protective Properties ◽  
Conductive Material ◽  
Time Extension ◽  
Heating Up ◽  
Dope Concentration

Paper presents the problem of heating the damaged insulation of an orbiter. Changes of the insulation?s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. An iterative algorithm determining a variable of dope concentration in the material was developed. Insulating material LI900 was used for calculations. Determination of distribution of conductive material concentration was made for materials which, after verification, demonstrated the most beneficial effect on protective properties of the modified insulation layer. Change of properties was to enable time extension of the LI900 insulation tile heating up to the maximal temperature and, additionally, to lowering this temperature.

Optimization of the heat flow by solving inverse problem in the protective layer of the TPS panel

2019 ◽  
Vol 30 (6) ◽  
pp. 2989-3003 ◽  
Author(s):  
Łukasz Brodzik ◽  
Andrzej Frąckowiak
Keyword(s):  
Protective Layer ◽  
Inverse Heat Conduction ◽  
Insulation Layer ◽  
Protective Properties ◽  
Content Type ◽  
Conductive Material ◽  
Time Extension ◽  
Inverse Heat Conduction Problems ◽  
Heating Up

Purpose This paper aims to present the problem of heating the damaged insulation of an orbiter. Design/methodology/approach Changes of the insulation’s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. An iterative algorithm determining a variable of dope concentration in the material was developed. Findings Determination of distribution of conductive material concentration was made for materials which, after verification, demonstrated the most beneficial effect on protective properties of the modified insulation layer. The problem of determining the distribution of metal filings concentration in the insulation layer of the coating belongs to inverse heat conduction problems. Originality/value Change of properties was to enable time extension of the LI900 insulation tile heating up to the maximal temperature and, additionally, to lowering this temperature.

scholarly journals Determination of distribution of heat-conducting material concentration in protective layer of TPS panel

2018 ◽  
Vol 240 ◽  
pp. 01007
Author(s):  
Łukasz Brodzik ◽  
Andrzej Frąckowiak
Keyword(s):  
Volume Fraction ◽  
Protective Layer ◽  
Aluminum Surface ◽  
Heat Conducting ◽  
Conducting Material ◽  
Insulating Material ◽  
Conductive Material ◽  
Percentage Volume ◽  
Constant Percentage

Paper presents the problem of heating the damaged insulation of an orbiter. Changes of the insulation’s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. The analysis was made using insulating material LI900 and beryllium dope. In the paper was investigated the effect of the dopant’s share on the temperature distribution on the aluminum surface. This influence was depended on the size of the damage, defined by parameter D, as well as a constant percentage volume fraction.

scholarly journals ASSESSMENT OF THE DEPTH AND RATE OF CORROSION IN STEEL REINFORCEMENT OF REINFORCED CONCRETE CULVERTS

2020 ◽  
Author(s):  
Alexandr Vasiliev ◽  
Svetlana Daškevič
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Damage ◽  
Steel Reinforcement ◽  
Operating Conditions ◽  
Protective Properties ◽  
Open Atmosphere ◽  
Concrete Elements ◽  
Corrosion State

Based on the results of many research years on concrete carbonisation: both immediately after manufacture (using heat-moisture treatment) and in reinforced concrete elements operated for the periods of various length (in an open atmosphere); the effect of carbonisation on the change in the protective properties of concrete in relation to steel reinforcement; for determination of the dependence of the corrosion state of steel reinforcement on the degree of concrete carbonisation in the area of steel reinforcement; the obtained regression dependences of the change (by time in the cross section) of the degree of concrete carbonisation of various classes in strength, – the analysis of the time of the onset of the boundary values of the degrees of concrete carbonisation (strength classes C12/15–C30/37) for the operating conditions of the open atmosphere was performed. Based on it, the regression dependences of the time variation of the depth of corrosion damage of steel reinforcement were construed (for fixed thicknesses of the concrete protective layer). The obtained nature of dependences made it possible to offer, in a general form, the regression dependences of the depth of corrosion damage and corrosion rate of steel reinforcement for concretes (strength classes C12/15–C30/37) for operating conditions in open atmosphere.

scholarly journals Thermal Modernization of the Panel Buildings External Walls

2018 ◽  
Vol 7 (3.2) ◽  
pp. 116
Author(s):  
Olena Filonenko ◽  
Oleg Yurin ◽  
Olga Kodak
Keyword(s):  
Heat Transfer ◽  
Thermal Protection ◽  
Residential Buildings ◽  
Outer Wall ◽  
Temperature Fields ◽  
Heat Conducting ◽  
Protection Level ◽  
Protective Properties ◽  
Wall Panels ◽  
Before And After

The thermal protection level of the first mass series panel buildings (series 111-94) is the lowest among residential buildings in Poltava. The problems of these buildings’ thermal modernization, is consideration of heat-conducting inclusions effect on the reduced resistance to heat transfer. In the studies such heat-conducting inclusions as the panel joints’ design, the window slope and the external wall geometry (the external corner) were taken into account. Studies were performed for the four pattern sections of the outer wall. Panels of two thickness variants with two joint designs were under consideration.To analyze the thermal protection level, the results of the two-dimensional temperature fields’ calculations were used. The analysis of the wall panels’ thermal protection level before the thermal modernization was performed. The magnitude of the heat conducting inclusions effect on reduced resistance of the walling to the heat transfer before and after the thermal modernization is determined. Possible ways of improving the wall panels’ heat-protective properties to the level of the standards in Ukraine are considered. The optimal variant of insulation for each pattern was chosen.  

The determination of thermal stresses in dissimilar media

1981 ◽  
Vol 89 (3) ◽  
pp. 533-542 ◽  
Author(s):  
K. Aderogba
Keyword(s):  
Half Space ◽  
Thermal Stresses ◽  
Practical Importance ◽  
Invariant Form ◽  
Heat Conducting ◽  
Conducting Material ◽  
Image Position ◽  
Quantity Of Heat

AbstractIt is shown that if, in an infinite homogeneous unbounded elastic heat-conducting solid, we are given the thermal stresses which arise when any arbitrarily shaped subregion of the upper half-space z > 0 is emitting any quantity of heat into the surrounding, then on introducing a different heat-conducting material into the half-space z < 0, the new thermal stresses in z >0 and in z < 0 are explicitly expressible in an invariant form in terms of the known thermal stresses in the homogeneous infinite solid. Specialization of the derived dependence shows that the physically interesting interfacial discontinuities inherent in the problem admit the representationwhile the traction transmitted across the interface takes the formwhere αi and βi are constants. An application is then made to the case when the region emitting heat into the surrounding is ellipsoidal, since this is a fundamental shape of practical importance. Applications can however be made to any shape of the region emitting heat, provided that the corresponding harmonic and biharmonic potentials are available.The paper may be considered to have its origin in the half-space theorem of Lorentz in hydrodynamics.

Locating complex eigenvalues for analytical eddy-current models used to detect flaws

2019 ◽  
Vol 38 (6) ◽  
pp. 1800-1809
Author(s):  
Grzegorz Tytko ◽  
Łukasz Dawidowski
Keyword(s):  
Eddy Current ◽  
Design Methodology ◽  
Complex Function ◽  
Precise Determination ◽  
Argument Principle ◽  
Content Type ◽  
Conductive Material ◽  
Complex Roots ◽  
Complex Eigenvalues

Purpose Discrete eigenvalues occur in eddy current problems in which the solution domain was truncated on its edge. In case of conductive material with a hole, the eigenvalues are complex numbers. Their computation consists of finding complex roots of a complex function that satisfies the electromagnetic interface conditions. The purpose of this paper is to present a method of computing complex eigenvalues that are roots of such a function. Design/methodology/approach The proposed approach involves precise determination of regions in which the roots are found and applying sets of initial points, as well as the Cauchy argument principle to calculate them. Findings The elaborated algorithm was implemented in Matlab and the obtained results were verified using Newton’s method and the fsolve procedure. Both in the case of magnetic and nonmagnetic materials, such a solution was the only one that did not skip any of the eigenvalues, obtaining the results in the shortest time. Originality/value The paper presents a new effective method of locating complex eigenvalues for analytical solutions of eddy current problems containing a conductive material with a hole.

scholarly journals Manjing : Proses Regenerasi Pengrajin Marmer

2020 ◽  
Vol 4 (1) ◽  
pp. 1-10
Author(s):  
Adin Ariyanti Dewi ◽  
Umi Dayati ◽  
Ach Rasyad
Keyword(s):  
Qualitative Research ◽  
Data Analysis ◽  
Informal Education ◽  
Cultural Inheritance ◽  
Data Display ◽  
Small Step ◽  
Time Extension ◽  
Technological Developments ◽  
Three Stages

AbstrakPewarisan budaya menjadi langkah kecil untuk dapat terus melestarikan budaya di suatu daerah. Namun, perkembangan teknologi terkadang mampu menggeser upaya pewarisan budaya tersebut. Penelitian ini bertujuan untuk mendeskripsikan proses pewarisan budaya keterampilan dalam pembuatan kerajinan marmer melalui kegiatan “manjing”. Penelitian ini menggunakan metode penelitian kualitatif melalui studi fenomenologi. Pengumpulan data dilakukan melalui teknik observasi, wawancara, dan dokumentasi. Analisis data dilakukan dengan menggunakan tiga tahap yakni (1) reduksi data, (2) display data, dan (3) penarikan kesimpulan. Penentuan keabsahan data dengan menggunakan teknik perpanjangan waktu penelitian dan triangulasi. Hasil penelitian menunjukkan bahwa kegiatan manjing dilakukan secara rutin. Proses pewarisan dilakukan oleh pengrajin marmer junior mulai dari upaya mengamati, menirukan, dan mempraktekkan hal-hal apa saja yang dilakukan oleh pengrajin marmer senior. Proses pewarisan budaya difokuskan pada kreativitas pembuatan kerajinan marmer. Upaya ini terdapat unsur pembelajaran di dalamnya, dalam konsep pendidikan kemudian proses ini termasuk dalam ranah pendidikan informal.AbstractCultural inheritance is a small step to be able to continue to preserve culture in an area. However, technological developments are sometimes able to shift the effort of cultural inheritance. This study aims to describe the process of cultural inheritance of skills in making marble crafts through "manjing" activities. This research uses qualitative research methods through phenomenology studies. Data collection is done through observation, interview, and documentation techniques. Data analysis was performed using three stages namely (1) data reduction, (2) data display, and (3) conclusion drawing. Determination of the validity of the data by using research time extension and triangulation techniques. The results showed that the Manjing activities were carried out routinely. The process of inheritance is carried out by junior marble craftsmen from the effort of observing, imitating, and practicing what things are done by senior marble craftsmen. The process of cultural inheritance is focused on the creativity of making marble handicrafts. This effort has an element of learning in it, in the concept of education then this process is included in the realm of informal education.

scholarly journals Determination of crystallization enthalpies of some organic peroxides by a differential isothermal calorimeter

2021 ◽  
pp. 90-94
Keyword(s):  
Supercooled Liquids ◽  
Sublimation Enthalpy ◽  
Residual Pressure ◽  
Heat Conducting ◽  
Dicumyl Peroxide ◽  
Organic Substances ◽  
Fusion Temperature ◽  
The Difference ◽  
Isothermal Calorimeter

We developed a method for determination of the crystallization enthalpy of organic substances in a heat-conducting calorimeter at a temperature close to 298 K. Crystallization was conducted in the MID-200 calorimeter using an ampoule technique. The volume of ampoules, which contain the supercooled liquids, was approximately 0.2 cm3. The residual pressure was 650 Pa to lessen the heat loss. A few crystals of the material under investigation were employed as the crystallization centers. Based on the results of the experiment, the crystallization enthalpies of dicumyl peroxide, peroxyoctanoic acid and di-tert-butylperoxy isophthalate were determined. The vaporization and sublimation enthalpies of peroxyoctanoic acid were assessed using an ampoule method in the calorimeter. It was established that dicumyl peroxide which was supercooled 14 K below the fusion temperature exhibited a 20% increase in crystallization enthalpy as compared with that calculated from the difference between vaporization and sublimation enthalpy. At the same time, the crystallization enthalpy of peroxyoctanoic acid supercooled by 5 K was equal to that calculated from the difference between vaporization and sublimation enthalpy within the limiting experimental error. The received data show that the proposed method is promising for determining the heat of crystallization of liquids that are able to exist in a supercooled state during some time.

scholarly journals Features of the Surface and Subsurface Waves Application for Ultrasonic Evaluation of Physicomechanical Properties of Solids. Part 1. Influence of the Geometrical Parameters

2018 ◽  
Vol 9 (4) ◽  
pp. 325-326
Author(s):  
A. R. Baev ◽  
A. L. Mayorov ◽  
M. V. Asadchaya ◽  
V. N. Levkovich ◽  
K. G. Zhavoronkov
Keyword(s):  
Protective Coating ◽  
Layer Structure ◽  
Base Material ◽  
Protective Layer ◽  
Body Waves ◽  
Measuring System ◽  
Geometrical Parameters ◽  
Small Aperture ◽  
Ultrasonic Evaluation

Application of surface and subsurface waves for control of objects with a double-layer structure allows to extend possibilities of diagnostics of their physico-mechanical properties. The purpose of work was to determine conditions and offer recommendations providing measuring of ultrasonic velocity and amplitude of the former modes in protective layers and in basis of object at one-sided access to its surface.The analysis of an acoustic path of a measuring system in relation to ultrasonic evaluation of the objects having the restricted sizes and the protective coating according to velocity data of the surface and subsurface waves propagation is made. On the basis of representations of beam acoustics the dependences connecting a wavelength of the excited surface and subsurface modes, thickness and width of a controlled object, acoustic base of a sounding are defined. There are to provide a condition leveling of the influence of an acoustical noise created by the reflected and accompanying waves on parameters of acoustic signal with the given quantity of oscillations in an impulse.The principle opportunity is shown and conditions for determination of velocity of subsurface body waves in the base material which is under a protective coating layer are established. For these purposes on the basis of use of the block of ultrasonic probes the optimum scheme of a sounding is offered and the analytical expression for calculation of required velocity considering varying of thickness of a covering is received.The method of acoustical measuring realized by a direct and reverse sounding of the objects with small aperture and angle probes was analysed and formulas for determination of speed of subsurface wave under protective layer of the wedge form have been got. An ultrasonic device is suggested for the excitationreception of subsurface waves with different speed in objects (on 20–35 %) using for the acoustic concordance of environments of metallic sound duct as a wedge. Possibility of leveling of interference in a protective layer to control efects in basis of material by a volume wave by creation of supporting echo-signal of longitudinal wave of the set frequency and entered normally to the surface of object was studied.

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