scholarly journals Changes in wood properties of chestnut wood structural elements with natural aging

2021 ◽  
Vol 23 ◽  
Author(s):  
Elif Topaloglu ◽  
Derya Ustaomer ◽  
Murat Ozturk ◽  
Emrah Pesman
Keyword(s):  
Natural Aging ◽  
Wood Properties ◽  
Structural Elements ◽  
Chestnut Wood

scholarly journals Single-Coil Eddy Current Sensors and Their Application for Monitoring the Dangerous States of Gas-Turbine Engines

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2107 ◽  
Author(s):  
Sergey Borovik ◽  
Yuriy Sekisov
Keyword(s):  
Gas Turbine ◽  
Eddy Current ◽  
Natural Aging ◽  
Turbine Engines ◽  
Radial Clearance ◽  
Gas Turbine Engines ◽  
Structural Elements ◽  
Single Coil ◽  
The Impact ◽  
Blade Tips

The creation and exploitation of gas turbine engines (GTE) often involve two mutually exclusive tasks related to ensuring the highest reliability while achieving a good economic and environmental performance of the power plant. The value of the radial clearance between the blade tips of the compressor or turbine and the stator is a parameter that has a significant impact on the efficiency and safety of the GTE. However, the radial displacements that form tip clearances are only one of the components of the displacements made by GTE elements due to the action of power loads and thermal deformations during engines’ operation. The impact of loads in conjunction with natural aging is also the reason for the wear of the GTE’s structural elements (for example, bearing assemblies) and the loss of their mechanical strength. The article provides an overview of the methods and tools for monitoring the dangerous states of the GTE (blade tips clearances, impellers and shafts displacements, debris detecting in lubrication system) based on the single-coil eddy current sensor, which remains operational at the temperatures above 1200 °C. The examples of practical application of the systems with such sensors in bench tests of the GTE are given.

scholarly journals Relationship Between Growth Stress, Mechanical-Physical Properties and Proportion of Fibre with Gelatinous Layer in Chestnut (Castanea Sativa Mill.)

Holzforschung ◽  
2003 ◽  
Vol 57 (2) ◽  
pp. 189-195 ◽  
Author(s):  
B. Clair ◽  
J. Ruelle ◽  
B. Thibaut
Keyword(s):  
Physical Properties ◽  
Castanea Sativa ◽  
Wood Properties ◽  
Growth Stress ◽  
Gelatinous Layer ◽  
Basic Model ◽  
Mechanical And Physical Properties ◽  
Castanea Sativa Mill ◽  
Chestnut Wood

Summary A range of mechanical and physical properties were determined for 96 specimens of chestnut wood and for wood types ranging from compression to tension wood; tests included (1) growth stress, (2) longitudinal Young's modulus in green and air-dried states (3) shrinkage in longitudinal and tangential directions. Anatomical observations permitted determination of the proportion of fibres with a gelatinous layer. The influence of these atypical fibres on macroscopic wood properties is examined and discussed. A basic model is proposed to determine their properties in theoretically isolated conditions.

Restoration of Structural Timber Elements Using Epoxy Resin: Analysis of Mechanical Properties

2013 ◽  
Vol 778 ◽  
pp. 582-587 ◽  
Author(s):  
Marília da Silva Bertolini ◽  
Laurenn Borges de Macedo ◽  
Diego Henrique de Almeida ◽  
Felipe Hideyoshi Icimoto ◽  
Francisco Antonio Rocco Lahr
Keyword(s):  
Cultural Heritage ◽  
Epoxy Resin ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Structural Characteristics ◽  
Conservation Status ◽  
Wood Properties ◽  
Structural Timber ◽  
Structural Elements ◽  
Structural Shocks

Brazil cultural heritage is composed by numerous constructions that describe the various historical periods lived by country. Constructions arent in good conservation status, showing systematically some deterioration level of their structural elements, among them those of wood. Restoration process aims to preserve the identity of original cultural heritage. It is essential maintain structural characteristics related to mechanical loads response which are closely dependent on wood properties avoiding possible structural shocks. Wood deterioration can be characterized by fungi decay or termite attack. Depending on level and position of the deteriorated area in structural set, local interventions are enough to maintain structural integrity. Polymeric resins are material options that can be used when removed these deteriorated regions, requiring compatibility with wood to maintain structural elements properties. This paper aims use of a technical for restoring structural timber from historic buildings, based on removal of decayed regions and filling them with epoxy resin. To analyze restoration effectiveness, properties in static bending, according to Brazilian standard, were determined. Samples were produced containing one and three restorations along the specimens (105 cm in length and nominal square cross section of 4.5 cm side), on the same side. Samples of Pinus taeda with gaps generated in the specimens with dimensions of 1.10 cm in depth and 8 cm in length were tested, with restorations placed in central region. For grafting of these gaps bicomponent epoxy resin was employed, prepared by mixing components in 1:1.5 proportions. Resin was injected into splices and its cure occurred in a seven days period, using methodology restoration to simulate a situation in which these structural elements have been used. Samples were requested in static bending to obtaining the product of inertia, analyzing the amendment under the aspect of tractioned and as well under compressed edge. It is observed the viability of restoration using filling epoxy resin in timber samples, considering the mechanical performance and practicality of the methodology for local keeping.

Effect of Severe Plastic Deformation on the Structure and Properties of the Aluminum Alloy System Al-Cu-Mg

2019 ◽  
Vol 822 ◽  
pp. 94-100
Author(s):  
Olga V. Paitova ◽  
Elena V. Bobruk ◽  
Svetlana Shasherina ◽  
Bu Fan Zhang
Keyword(s):  
Room Temperature ◽  
High Pressure Torsion ◽  
Natural Aging ◽  
Alloy System ◽  
Coarse Grained ◽  
Structural Elements ◽  
Structure And Properties ◽  
Transmission Electron ◽  
Temperature Standard ◽  
Local Shift

The structure and properties of discs from cast coarse-grained D16 alloy have been investigated with the help of optical metallography and transmission electron microscopy, after the traditional heat treatment (HT) modes or subjected to high pressure torsion (HPT) under pressure in 6 GPa at room temperature. Standard HT modes included: Т4 (hardening 495°С + natural aging at room temperature for 5 days) and Т6 (hardening 495°С + artificial aging at 185°С for 10 hours). It is shown that after HT of alloy D16 according to modes T6 and Т4, the sizes of the structural elements, compared with the original, decreased by about 4,8 times and the microhardness increased by 1,6 times. It is shown that after one or ten rotates of HPT in D16 alloy the sizes of structural elements, in comparison with initial, decreased by 393 and 899 times, and microhardness increased by 2,4 and 2,9 times, respectively. Detection of hardening hard, brittle and high-alloy copper γ2- phases (Cu9Al4) indicates the passage in the HPT process of the decomposition of a supersaturated solid solution (dynamic aging) in the planes of a local shift.

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

Designing TIMP (tissue inhibitor of metalloproteinases) variants that are selective metalloproteinase inhibitors

2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew
Keyword(s):  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Structural Basis ◽  
Structural Elements ◽  
Ridge Structure ◽  
Extracellular Matrix Components ◽  
Metalloproteinase Inhibitors ◽  
The Matrix ◽  
A Disintegrin And Metalloproteinase

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.

Formation Of An Estimate For A State Contract With A Firm Price In The Construction Sector

2020 ◽  
pp. 47-57
Keyword(s):  
Construction Projects ◽  
Cost Of Capital ◽  
Federal Budget ◽  
The State ◽  
Structural Elements ◽  
Construction Sector ◽  
Construction Process ◽  
Practical Application ◽  
Stage Of Development ◽  
Capital Construction

The issues of determining the estimated cost of capital construction projects with the involvement of Federal budget funds at the stage of development of project documentation, during verification of the accuracy of determining the estimated cost and the initial (maximum) contract price are considered. On the basis of the assessment of amendments to urban planning legislation for the purpose of implementing a state contract by the contractor ( based on the results of competitive procedures or without competitive procedures by decision of state authorities), the procedure for forming the estimate as part of a state (municipal) contract, the price of which is firm, is presented. For the purpose of mutual settlements between the customer and the contractor for the work performed, the formation of primary accounting documentation, as well as for checking the work performed by regulatory authorities, an example of drawing up an estimate of the state (municipal) contract on the basis of grouping costs according to structural elements and complexes of work is given. The result of the research conducted was the development of regulations and the formation of criteria for their practical application by state bodies, institutions, organizations and other participants in the investment-construction process, as well as recipients of budget funds, who perform the functions of the state (municipal) customer, developer and technical customer.

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