scholarly journals ANALYSIS OF THE FIRE‐PROTECTION IMPREGNATION INFLUENCE ON WOOD STRENGTH

2007 ◽  
Vol 13 (2) ◽  
pp. 79-85 ◽  
Author(s):  
Zoja Bednarek ◽  
Agnieszka Kaliszuk-Wietecka
Keyword(s):  
Impact Strength ◽  
Fire Protection ◽  
Elevated Temperatures ◽  
Pressure Method ◽  
Dynamic Bending ◽  
Result Analysis ◽  
Wood Strength

The paper presents the description, results and result analysis for the effect of fire‐protection impregnation with a salt‐containing agent, made by a vacuum‐and‐pressure method, on wood strength. A significant effect of this impregnation type was proven for the strength types as follows: static bending, tension, lengthwise compression (ie along fibres), crosswise compression (ie across fibres), as well as for dynamic bending and impact strength in normal and elevated temperatures.

scholarly journals Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

2017 ◽  
Vol 17 (3) ◽  
pp. 73-78 ◽  
Author(s):  
A. Kurzawa ◽  
J.W. Kaczmar
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Elevated Temperatures ◽  
Al Alloy ◽  
Pressure Infiltration ◽  
Reinforcing Particles ◽  
Strength Based ◽  
Crack Mechanics ◽  
The Matrix ◽  
Microscopic Studies

AbstractThe paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3particles of 3-6μm with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by volume) at an ambient of 23°C and at elevated temperatures to a maximum of 300°C. The results of this study were referred to the unreinforced matrix EN AC-44200 and to its hardness and tensile strength. Based on microscopic studies, an analysis and description of crack mechanics of the tested materials were performed. Structural analysis of a fracture surface, material structures under the crack surfaces of the matrix and cracking of the reinforcing particles were performed.

scholarly journals Toughness and Impact Strength in Dynamic Bending of Wood as a Function of the Modulus of Elasticity and the Strength in Compression to the Grain

2017 ◽  
Vol 7 (4) ◽  
pp. 61-67 ◽  
Author(s):  
Aline Pinto Moreira ◽  
Emily da Silveira ◽  
Diego Henrique de Almeida ◽  
Tiago Hendrigo de Almeida ◽  
Tulio Hallak Panzera ◽  
...  
Keyword(s):  
Impact Strength ◽  
Modulus Of Elasticity ◽  
Strength In Compression ◽  
Dynamic Bending

Buna for Hard Rubber Linings

1941 ◽  
Vol 14 (4) ◽  
pp. 899-913 ◽  
Author(s):  
E. Gartner
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Natural Rubber ◽  
Narrow Range ◽  
Brinell Hardness ◽  
Good Material ◽  
Shock Resistance ◽  
Dynamic Bending

Abstract On the basis of the investigations described in the present paper, certain rules or directions for obtaining the most desirable properties with the various types of artificial rubbers can be laid down. Brinell hardness.—The higher the proportion of vinyl component in a mixed butadiene polymer, the harder is the resulting vulcanizate within the relatively narrow range of percentages of sulfur which were tested. In this respect, acrylonitrile has a greater effect than does styrene. Mechanical properties.—As far as mechanical properties are concerned, Perbunan-Extra is an extraordinarily good material for, in addition to giving high Brinell hardness and tensile strength, it also shows good shock resistance and impact strength. Buna-SS and Perbunan-Extra give, within the range of hardnesses tested, high Martens values. Compared with natural rubber, their resistances to dynamic bending are particularly good.

scholarly journals The Experimental Study of Performance Impairment of Big Data Processing in Dynamic and Opportunistic Environments

2020 ◽  
pp. 776-789
Author(s):  
Wei Li ◽  
◽  
William W. Guo
Keyword(s):  
Big Data ◽  
Impact Strength ◽  
Data Processing ◽  
Impact Factors ◽  
Distributed Environments ◽  
Distributed Environment ◽  
Big Data Processing ◽  
Performance Impairment ◽  
Result Analysis ◽  
The Impact

In contrast to HPC clusters, when big data is processing in a distributed, particularly dynamic and opportunistic environment, the overall performance must be impaired and even bottlenecked by the dynamics of overlay and the opportunism of computing nodes. The dynamics and opportunism are caused by churn and unreliability of a generic distributed environment, and they cannot be ignored or avoided. Understanding impact factors, their impact strength and the relevance between these impacts is the foundation of potential optimization. This paper derives the research background, methodology and results by reasoning the necessity of distributed environments for big data processing, scrutinizing the dynamics and opportunism of distributed environments, classifying impact factors, proposing evaluation metrics and carrying out a series of intensive experiments. The result analysis of this paper provides important insights to the impact strength of the factors and the relevance of impact across the factors. The production of the results aims at paving a way to future optimization or avoidance of potential bottlenecks for big data processing in distributed environments.

scholarly journals An Application Review of Fiber-Reinforced Geopolymer Composite

Fibers ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 23
Author(s):  
Sneha Samal ◽  
Ignazio Blanco
Keyword(s):  
Impact Strength ◽  
Energy Absorption ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Fiber Reinforced ◽  
Damage Area ◽  
Structural Applications ◽  
Extra Step ◽  
Geopolymer Composites

Fiber-reinforced geopolymer composites (FRGCs) were considered in terms of application in various areas, and a review is presented in this article. FRGCs are emerging as environmentally friendly materials, replacing cement in the construction industry. An alternative inorganic binder such as a geopolymer matrix promotes environmental awareness on releasing less CO2. The inorganic matrix geopolymer is considered a greener cement for FRGCs. Various types of fiber reinforcements and their role toward the improvement of tensile, flexural, impact strength, fracture toughness, and energy absorption in overall mechanical performance in FRGCs were discussed. FRGCs and their properties in mechanical response, with correlation toward microstructure evolution at room and elevated temperatures, were also discussed. Simultaneously, the durability and impact strength of FRGCs and damage area as a function of the energy absorption were presented with 3D reconstruction images. Moreover, 3D images will cover the internal volume of the FRGCs with internal porosity and fiber orientation. Hybrid fiber reinforcement adds an extra step for the application of geopolymer composites for structural applications.

scholarly journals Residual Repeated Impact Strength of Concrete Exposed to Elevated Temperatures

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 941
Author(s):  
Raad A. Al-Ameri ◽  
Sallal R. Abid ◽  
G. Murali ◽  
Sajjad H. Ali ◽  
Mustafa Özakça
Keyword(s):  
High Temperature ◽  
Impact Strength ◽  
Elevated Temperatures ◽  
Impact Resistance ◽  
Test Results ◽  
Repeated Impact ◽  
High Temperature Exposure ◽  
Compressive And Flexural Strengths ◽  
Temperature Exposure ◽  
The Impact

Portland cement concrete is known to have good fire resistance; however, its strength would be degraded after exposure to the temperatures of fire. Repeated low-velocity impacts are a type of probable accidental load in many types of structures. Although there is a rich body of literature on the residual mechanical properties of concrete after high temperature exposure, the residual repeated impact performance of concrete has still not been well explored. For this purpose, an experimental study was conducted in this work to evaluate the effect of high temperatures on the repeated impact strength of normal strength concrete. Seven identical concrete patches with six disc specimens each were cast and tested using the ACI 544-2R repeated impact setup at ambient temperature and after exposure to 100, 200, 300, 400, 500 and 500 °C. Similarly, six cubes and six prisms from each patch were used to evaluate the residual compressive and flexural strengths at the same conditions. Additionally, the scattering of the impact strength results was examined using three methods of the Weibull distribution, and the results are presented in terms of reliability. The test results show that the cracking and failure impact numbers of specimens heated to 100 °C reduced slightly by only 2.4 and 3.5%, respectively, while heating to higher temperatures deteriorated the impact resistance much faster than the compressive and flexural strengths. The percentage reduction in impact resistance at 600 °C was generally higher than 96%. It was also found that the deduction trend of the impact strength with temperature is more related to that of the flexural strength than the compressive strength. The test results also show that, within the limits of the adopted concrete type and conducted tests, the strength reduction after high temperature exposure is related to the percentage weight loss.

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

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