scholarly journals CHANGE IN THE HYGROSCOPICITY OF PINE CORE WOOD IN A TREE TRUNK DAMAGED BY FIRE

2021 ◽  
Author(s):  
Aleksey Platonov ◽  
A. Popov ◽  
Svetlana Snegireva ◽  
Ekaterina Kantieva
Keyword(s):  
High Temperature ◽  
Practical Interest ◽  
Physical And Mechanical Properties ◽  
Middle Part ◽  
Hydroxyl Groups ◽  
Tree Trunk ◽  
Voronezh Region ◽  
Great Practical Interest ◽  
Partial Blocking ◽  
High Level

Fires have a significant impact on the structure and physical and mechanical properties of wood. The degree of this effect depends on the type of fire, its intensity and the duration of exposure to high temperature. The greatest impact on the wood occurs with a strong grassroots and general top fire. Gorenje fire is characterized by a high intensity of burning of forest floor and undergrowth, as well as the crown of trees. The effect of the high temperature of the fire on the tree trunk is different. As a result of the destruction of wood, there is a partial blocking of hydroxyl groups in the cellulose molecules and leads to a decrease in the hygroscopicity limit of wood. Of great practical interest is the change in the hygroscopicity of wood damaged by fire. The aim of this study is to determine the changes in the hygroscopicity of the core wood of Scots pine (Pinus sylvestris L.)after damage by a strong grassroots and general high-level fire. The studies were carried out on wood growing on the territory of the UOL in the Voronezh region, on samples of pine core wood cut from the clump, middle and apex parts of the trunk. It was experimentally established that the greatest decrease in the hygroscopicity of pine core wood occurred in the left part of the trunk, and the smallest in the middle part, after fire damage.

NIROSTA 4002

Alloy Digest ◽  
2002 ◽  
Vol 51 (6) ◽  
Keyword(s):  
Hydrogen Sulfide ◽  
High Temperature ◽  
Physical Properties ◽  
Structural Steel ◽  
Oil Industry ◽  
Heat Treating ◽  
Mineral Oil ◽  
Chromium Steel ◽  
Temperature Performance ◽  
High Level

Abstract NIROSTA 4002 is an apparatus structural steel with 13% Cr. It is used for crack-resistant installations in the mineral oil industry because it has a high level of resistance against hydrogen and hydrogen sulfide. This chromium steel requires a smoothened surface free from residues in order to achieve optimal resistance to corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SS-856. Producer or source: ThyssenKrupp Nirosta GmbH.

AL 4565 ALLOY

Alloy Digest ◽  
2004 ◽  
Vol 53 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
High Resistance ◽  
Flue Gas ◽  
Heat Treating ◽  
Flue Gas Desulfurization ◽  
High Nitrogen ◽  
Temperature Performance ◽  
High Level

Abstract AL 4565 alloy has a high level of austenitizers, which provides the microstructure with a high resistance to sigma formation during welding. The high nitrogen also gives the alloy superior strength among the austenitics. Applications include flue gas desulfurization and handling seawater. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating and joining. Filing Code: SS-906. Producer or source: Allegheny Ludlum Corporation.

Cyclic Methylsiloxanes as Working Fluids for Space Power Cycles

1993 ◽  
Vol 115 (3) ◽  
pp. 130-137 ◽  
Author(s):  
G. Angelino ◽  
C. Invernizzi
Keyword(s):  
High Temperature ◽  
Full Potential ◽  
Working Fluids ◽  
Power Cycles ◽  
Thermodynamic Performance ◽  
High Level ◽  
Organic Fluids ◽  
Large Wheel ◽  
Turbine Exhaust ◽  
Fast Rotating

The potential merits of cyclic polymethylsiloxanes, particularly those conventionally denominated D4 and D5, as working fluids for space power cycles are discussed. The attractive technical characteristics of these substances which are fully nontoxic, moderately flammable, and stable at high temperature are presented. Some experimental results on vapor pressure and on thermal stability are reported. A maximum operating temperature of about 400°C appears achievable. A comprehensive thermodynamic analysis comparing siloxanes with other classes of high temperature fluids is performed. The peculiar characters of siloxane cycles are found to be: a good overall efficiency achieved through a massive regeneration, a moderate expansion work, and an abundant volume flow at turbine exhaust. A number of two-stage turbines for two power levels (i.e., 30 and 5 kW) were designed using an appropriate optimization program. The resulting main features of such expanders were a satisfactory efficiency, a low rotating and peripheral speed, and a comparatively large wheel diameter. These characteristics seem of particular interest for low capacity systems where, with other fluids, turbines tend to be impractically small and fast rotating and where a high level of regeneration becomes more acceptable. In considering for the sake of comparison the thermodynamic performance of many classes of organic fluids, it becomes apparent that the full potential of organic power cycles in view of the variety of future needs has not yet been thoroughly investigated.

Effect of High-Temperature Defibration on the Chemical Structure of Hardwood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 51-59 ◽  
Author(s):  
P. Widsten ◽  
J.E. Laine ◽  
P. Qvintus-Leino ◽  
S. Tuominen
Keyword(s):  
High Temperature ◽  
Lignin Content ◽  
Bulk Composition ◽  
Chemical Properties ◽  
Water Extract ◽  
Fiber Surface ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Surface Chemical ◽  
Alkyl Aryl

Summary The present paper aims at elucidating the effect of high-temperature defibration at different temperatures on the bulk and surface chemical properties of defibrated birch, aspen and eucalypt. The results indicate that defibration of these hardwoods results in partial depolymerization of fiber lignin via (homolytic) cleavage of interunit alkyl-aryl (β-O-4) ether bonds. This increases the phenolic hydroxyl content and produces relatively stable (phenoxy) radicals. Syringyl-type lignin is more extensively depolymerized than guaiacyl-type lignin. Defibration generates water-extractable material, which is enriched in hemicellulose-derived carbohydrates and has a substantial content of aromatic compounds rich in phenolic hydroxyl groups. The amount of water-extract and the extent of lignin interunit ether bond cleavage increase with an increase in defibration temperature. The differences between various hardwood species in this respect are small. The surface chemical composition of the fibers differs considerably from their bulk composition, but is not significantly influenced by variations in defibration temperature. Lipophilic extractives cover a large portion of the fiber surface, while the lignin content of lipophilic extractives-free fiber surfaces is 2–3 times as high as the bulk lignin content of the fibers.

Intermetallics of Aluminum

2019 ◽  
Author(s):  
Georg Frommeyer ◽  
Sven Knippscheer
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Temperature ◽  
Physical Properties ◽  
Intermetallic Compounds ◽  
Oxidation Behavior ◽  
Physical And Mechanical Properties ◽  
Structural Materials

Aluminum-rich intermetallic compounds of the Al3X-type with transmission metals (X = Ti. Zr, Nb, V) of Groups IVb and Vb are of interest in the development of novel high-temperature and lightweight structural materials. This article describes the important physical and mechanical properties of trialuminides with DO22 structure and their L12 variations. Topical coverage includes: crystal structure and selected physical properties, plastic deformation, oxidation behavior, and applications.

scholarly journals Bryoflora of botanic gardens, arboreta and dendrological parks in Voronezh Region

2020 ◽  
Vol 19 (1) ◽  
pp. 156-161
Author(s):  
N. N. Popova
Keyword(s):  
Botanic Gardens ◽  
Satisfactory Condition ◽  
Floral Diversity ◽  
Voronezh Region ◽  
High Level

The brioflora of Botanic gardens and dendrological parks of Voronezh Region (2018) includes 66 speciesand is characterized by a fairly high level of structural and floral diversity; it includes 3 species listed in the regional Redbook; the nemoral epiphytic complex is fully represented; measures are needed for cataloguing all components of thebiota, carefully reconstruct them and maintain them in a satisfactory condition to increase the environmental role of thestudied objects.

A MODEL HIERARCHY FOR IONOSPHERIC PLASMA MODELING

2004 ◽  
Vol 14 (03) ◽  
pp. 393-415 ◽  
Author(s):  
CHRISTOPHE BESSE ◽  
PIERRE DEGOND ◽  
FABRICE DELUZET ◽  
JEAN CLAUDEL ◽  
GÉRARD GALLICE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Plasma Density ◽  
Maxwell Equations ◽  
Ionospheric Plasma ◽  
Practical Interest ◽  
Plasma Modeling ◽  
Model Hierarchy ◽  
Great Practical Interest ◽  
Two Fluid ◽  
Insight Into

This paper deals with the modeling of the ionospheric plasma. Starting from the two-fluid Euler–Maxwell equations, we present two hierarchies of models. The MHD hierarchy deals with large plasma density situations while the dynamo hierarchy is adapted to lower density situations. Most of the models encompassed by the dynamo hierarchy are classical ones, but we shall give a unified presentation of them which brings a new insight into their interrelations. By contrast, the MHD hierarchy involves a new (at least to the authors) model, the massless-MHD model. This is a diffusion system for the density and magnetic field which could be of great practical interest. Both hierarchies terminate with the "classical" Striation model, which we shall investigate in detail.

Seismic anisotropy

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 40-41 ◽  
Author(s):  
Leon Thomsen
Keyword(s):  
Future Development ◽  
Seismic Data ◽  
Seismic Anisotropy ◽  
Practical Interest ◽  
Exploration And Exploitation ◽  
Principal Reason ◽  
The Past ◽  
High Level ◽  
Effective Use

The topic of seismic anisotropy in exploration and exploitation has seen a great deal of progress in the past decade‐and‐a‐half. The principal reason for this is the increased (and increasing) quality of seismic data, of the processing done to it, and of the interpretation expected from it. No longer an academic subject of little practical interest, it is now often viewed as one of the crucial factors which, if not taken into account, severely hampers our effective use of the data. The following brief overview is not intended to be exhaustive, since any such attempt would surely be incomplete. However, it does provide a high‐level survey of the advances seen (at the end of this period) to be important by one who was closely involved, and it directly extrapolates this history to predict the future development of the topic.

scholarly journals Sticky Thermals: Evidence for a Dominant Balance between Buoyancy and Drag in Cloud Updrafts

2015 ◽  
Vol 72 (8) ◽  
pp. 2890-2901 ◽  
Author(s):  
David M. Romps ◽  
Alexander B. Charn
Keyword(s):  
Large Eddy Simulation ◽  
Practical Interest ◽  
Momentum Equation ◽  
Severe Weather ◽  
Convective Clouds ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Great Practical Interest ◽  
Natural Boundaries ◽  
Drag Law

Abstract The vertical velocities of convective clouds are of great practical interest because of their influence on many phenomena, including severe weather and stratospheric moistening. However, the magnitudes of forces giving rise to these vertical velocities are poorly understood, and the dominant balance is in dispute. Here, an algorithm is used to extract thousands of cloud thermals from a large-eddy simulation of deep and tropical maritime convection. Using a streamfunction to define natural boundaries for these thermals, the dominant balance in the vertical momentum equation is revealed. Cloud thermals rise with a nearly constant speed determined by their buoyancy and the standard drag law with a drag coefficient of 0.6. Contrary to suggestions that cloud thermals might be slippery, with a dominant balance between buoyancy and acceleration, cloud thermals are found here to be sticky, with a dominant balance between buoyancy and drag.

Giant condiloma of Bushke-Levenstein of anal canal and perianal skin. Clinical case

2021 ◽  
pp. 25-35
Author(s):  
Anton Ivanovich Grechin ◽  
Grigory Vladimirovich Rodoman ◽  
Evgeny Konstantinovich Naumov ◽  
Leonid Vladimirovich Kornev ◽  
Evgeny Mikhailovich Fominykh
Keyword(s):  
High Temperature ◽  
Literature Review ◽  
Clinical Case ◽  
Practical Interest ◽  
Perianal Skin ◽  
Evidence Based ◽  
Perianal Region ◽  
Healing Wound ◽  
Staged Treatment

The article is devoted to a rare disease of the perianal region — Buschke-Levenshtein tumor. A clinical case and a literature review on the etiology, pathogenesis and experience of treating such tumors are presented. Evidence based sources show that currently there is no generally accepted tactics of managing patients with this pathology. In this regard, each case of treatment of such patients is of not only scientific but also practical interest. In this case, the tactics of staged treatment with the use of high-temperature dissectors and immunocorrection was chosen, which made it possible to achieve a good clinical result without the formation of extensive and long-term non-healing wound defects in the perianal region.

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