Changes of Selected Structural and Mechanical Properties of the Strzelin Granites As Induced By Thermal Loads / Wpływ Obciążeń Termicznych Na Zmiany Niektórych Strukturalnych I Mechanicznych Właściwości Granitów Strzelińskich

2012 ◽  
Vol 57 (4) ◽  
pp. 951-974 ◽  
Author(s):  
Andrzej Nowakowski ◽  
Mariusz Młynarczuk
Keyword(s):  
Mechanical Properties ◽  
Nuclear Waste ◽  
Structural Changes ◽  
Structural Parameters ◽  
Total Porosity ◽  
Fracture Network ◽  
Qualitative Description ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Waste Repositories

Abstract Temperature is one of the basic factors influencing physical and structural properties of rocks. A quantitative and qualitative description of this influence becomes essential in underground construction and, in particular, in the construction of various underground storage facilities, including nuclear waste repositories. The present paper discusses the effects of temperature changes on selected mechanical and structural parameters of the Strzelin granites. Its authors focused on analyzing the changes of granite properties that accompany rapid temperature changes, for temperatures lower than 573ºC, which is the value at which the β - α phase transition in quartz occurs. Some of the criteria for selecting the temperature range were the results of measurements carried out at nuclear waste repositories. It was demonstrated that, as a result of the adopted procedure of heating and cooling of samples, the examined rock starts to reveal measurable structural changes, which, in turn, induces vital changes of its selected mechanical properties. In particular, it was shown that one of the quantities describing the structure of the rock - namely, the fracture network - grew significantly. As a consequence, vital changes could be observed in the following physical quantities characterizing the rock: primary wave velocity (vp), permeability coefficient (k), total porosity (n) and fracture porosity (η), limit of compressive strength (Rσ1) and the accompanying deformation (Rε1), Young’s modulus (E), and Poisson’s ratio (ν).

scholarly journals Modelling the change in structure and mechanical properties in dry-snow densification to ice

1998 ◽  
Vol 26 ◽  
pp. 45-50 ◽  
Author(s):  
Vladimir N. Golubev ◽  
Anatoly D. Frolov
Keyword(s):  
Mechanical Properties ◽  
Porous Media ◽  
Physical Properties ◽  
Coordination Number ◽  
Structural Changes ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Density Increase ◽  
Regular Packing ◽  
Good Agreement

The regular packing of spheres or polyhedrons of various shapes linked by rigid bonds is presented and discussed as a model of snow structure. Basic structural parameters of this model are: the coordination number and introduced dimensionless factors of friability and rigidity. The snow densification is described as successive changes of these parameters. Use of the model allows us to relate the density increase from ~130 to ~320, ~550, ~700, ~820 and 917 kg m−3, while the coordination number of the structure increases accordingly from 3 (friable hexagonal) to 4 (tetrahedral), 6 (cubic), 8, 10, 12 (dense hexagonal). These structural changes are in good agreement with the critical densities established in experimental studies of snow densification and the physical properties of snow. It is shown that the model presented allows us to estimate the mechanical properties of ice-porous media: Young’s modulus, Poisson’s ratio and strength.

scholarly journals The Role of Structure on Mechanical Properties of Nonwoven Fabrics

2001 ◽  
Vol os-10 (2) ◽  
pp. 1558925001OS-01 ◽  
Author(s):  
H.S. Kim ◽  
B. Pourdeyhimi
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Maximum Stress ◽  
Structural Parameters ◽  
Bonding Temperature ◽  
Tensile Modulus ◽  
Orientation Distribution ◽  
Nonwoven Fabrics ◽  
Fiber Orientation Distribution

The mechanical properties, namely, tensile modulus, maximum stress in tension and elongation at maximum stress of thermally point-bonded nonwoven fabrics with different bonding temperature have been evaluated. Image acquisition and analysis techniques have been used to quantify structural parameters such as fiber orientation distribution function, bond-region strain, and unit cell strain during controlled-deformation experiments and to identify failure mechanisms. We have shown that an in situ experimental visualization and measurement of the structural changes occurring during controlled-deformation experiments can help establish links between mechanical properties and the structure properties of nonwoven fabrics.

scholarly journals Modelling the change in structure and mechanical properties in dry-snow densification to ice

1998 ◽  
Vol 26 ◽  
pp. 45-50 ◽  
Author(s):  
Vladimir N. Golubev ◽  
Anatoly D. Frolov
Keyword(s):  
Mechanical Properties ◽  
Porous Media ◽  
Physical Properties ◽  
Coordination Number ◽  
Structural Changes ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Density Increase ◽  
Regular Packing ◽  
Good Agreement

The regular packing of spheres or polyhedrons of various shapes linked by rigid bonds is presented and discussed as a model of snow structure. Basic structural parameters of this model are: the coordination number and introduced dimensionless factors of friability and rigidity. The snow densification is described as successive changes of these parameters. Use of the model allows us to relate the density increase from ~130 to ~320, ~550, ~700, ~820 and 917 kg m−3, while the coordination number of the structure increases accordingly from 3 (friable hexagonal) to 4 (tetrahedral), 6 (cubic), 8, 10, 12 (dense hexagonal). These structural changes are in good agreement with the critical densities established in experimental studies of snow densification and the physical properties of snow. It is shown that the model presented allows us to estimate the mechanical properties of ice-porous media: Young’s modulus, Poisson’s ratio and strength.

Nuclear Waste Repositories in Crystalline Rock- an Overview of Flow and Nuclide Transport Mechanisms

1994 ◽  
Vol 353 ◽  
Author(s):  
Ivars Neretnieks
Keyword(s):  
Nuclear Waste ◽  
Field Experiments ◽  
Fracture Network ◽  
Crystalline Rock ◽  
Transport Mechanisms ◽  
The Matrix ◽  
Nuclide Transport ◽  
Waste Repositories ◽  
And Diffusion ◽  
Diffusion Properties

AbstractNuclides eventually escaping from nuclear waste repositories in crystalline rock will move with the seeping water in the fracture network. Most important nuclides interact physically or chemically with the rock and are expected to be considerably retarded allowing them to decay to insignificant concentrations. Velocity variations may allow some portions of the nuclides to move faster. Matrix diffusion and sorption on the surfaces of the rock are by far the most powerful retardation mechanisms and depend, in addition to the sorption and diffusion properties, directly on the magnitude of the “flow wetted surface”which is the contact surface between the mobile water carrying the nuclides and the fracture surfaces over which the nuclides diffuse into the matrix.A number of field experiments have been performed over the last 15 years to help validate the concepts and models and to obtain data. A number of such experiments are described and discussed in relation to the above issues.

INFLUENCE THE QUENCHING AND TEMPERING ON THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND SURFACE ROUGHNESS, OF MEDIUM CARBON STEEL

2018 ◽  
Vol 18 (1) ◽  
pp. 125-135
Author(s):  
Sattar H A Alfatlawi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Roughness ◽  
Carbon Steel ◽  
Cold Water ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Heating And Cooling ◽  
Treatment Processes ◽  
Quenching And Tempering

One of ways to improve properties of materials without changing the product shape toobtain the desired engineering applications is heating and cooling under effect of controlledsequence of heat treatment. The main aim of this study was to investigate the effect ofheating and cooling on the surface roughness, microstructure and some selected propertiessuch as the hardness and impact strength of Medium Carbon Steel which treated at differenttypes of heat treatment processes. Heat treatment achieved in this work was respectively,heating, quenching and tempering. The specimens were heated to 850°C and left for 45minutes inside the furnace as a holding time at that temperature, then quenching process wasperformed in four types of quenching media (still air, cold water (2°C), oil and polymersolution), respectively. Thereafter, the samples were tempered at 200°C, 400°C, and 600°Cwith one hour as a soaking time for each temperature, then were all cooled by still air. Whenthe heat treatment process was completed, the surface roughness, hardness, impact strengthand microstructure tests were performed. The results showed a change and clearimprovement of surface roughness, mechanical properties and microstructure afterquenching was achieved, as well as the change that took place due to the increasingtoughness and ductility by reducing of brittleness of samples.

POTOMAC

Alloy Digest ◽  
1975 ◽  
Vol 24 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Heat Treating ◽  
General Purpose ◽  
Low Carbon ◽  
Repeated Heating ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Temperature Performance ◽  
Heat Checking

Abstract POTOMAC is a general-purpose, low-carbon, chromium-molybdenum-tungsten hot-work steel. It has excellent resistance to shock and heat checking after repeated heating and cooling. Potomac is suitable for hot-work applications involving severe conditions of shock and sudden temperature changes. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-290. Producer or source: Allegheny Ludlum Corporation.

Quantitative relations between structure and antiinflammatory activity of aryloxoalkanoic acids

1988 ◽  
Vol 53 (8) ◽  
pp. 1862-1872 ◽  
Author(s):  
Miroslav Kuchař ◽  
Eva Maturová ◽  
Bohumila Brunová ◽  
Jaroslava Grimová ◽  
Hana Tomková ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Structural Changes ◽  
Antiinflammatory Activity ◽  
Structural Parameters ◽  
Considerable Effect ◽  
Antiinflammatory Effect ◽  
Prolonged Action ◽  
Preclinical Development ◽  
Indicator Variables ◽  
Inhibitory Activities

The antiinflammatory effect of a series of aryloxoalkanoic acids II and of their biphenyl derivatives III was examined by measuring the inhibition of the development of carageenan- and adjuvant-induced edemas. The quantitative relations between the antiinflammatory effect and physicochemical and structural parameters of the compounds tested were evaluated. The equations obtained by the method of regression analysis showed a significant linear dependence of both inhibitory activities on the lipophilicity of the compounds and a considerable effect of some structural changes as expressed by indicator variables. The antiinflammatory effect is especially enhanced in both tests by the presence of a cyclic substituent at the aromatic ring. The high antiinflammatory effect of biphenylyl derivatives III is paralleled by their prolonged action. The prolongation of the effect is most likely a result of a suitable biotransformation of acid III to an efficient metabolite. The structural requirements which resulted from both the regression analysis and from the hypothesis of biotransformation of acids III were utilized in the synthesis of suitably substituted biphenylyloxoalkanoic acids. By this approach derivatives IIIe-i were obtained some of which showed a high antiinflammatory and also protracted effect. 4-(2',4'-Difluorbiphenylyl)-4-oxo-2-methylbutanoic acid (VÚFB-16 066, Flobufen) was chosen for further preclinical development.

scholarly journals Damage Evolution of Granodiorite after Heating and Cooling Treatments

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 779
Author(s):  
Mohamed Gomah ◽  
Guichen Li ◽  
Salah Bader ◽  
Mohamed Elkarmoty ◽  
Mohamed Ismael
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Failure Mode ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Physical Parameters ◽  
Slow Cooling ◽  
Heating And Cooling ◽  
Natural Rock ◽  
The Impact

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

scholarly journals Needs of LMIC-based tobacco control advocates to counter tobacco industry policy interference: insights from semi-structured interviews

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e044710
Author(s):  
Britta Katharina Matthes ◽  
Lindsay Robertson ◽  
Anna B Gilmore
Keyword(s):  
Tobacco Control ◽  
Structural Changes ◽  
Tobacco Industry ◽  
Control Policy ◽  
Qualitative Description ◽  
Structured Interviews ◽  
Middle Income ◽  
Adoption And Implementation ◽  
National Coalition ◽  
Industry Policy

IntroductionAdvocacy is vital for advancing tobacco control and there has been considerable investment in this area. While much is known about tobacco industry interference (TII), there is little research on advocates’ efforts in countering TII and what they need to succeed. We sought to examine this and focused on low- and middle-income countries (LMICs) where adoption and implementation of the Framework Convention on Tobacco Control (FCTC) tend to remain slower and weaker.MethodWe interviewed 22 advocates from eight LMICs with recent progress in a tobacco control policy. We explored participants’ experiences in countering TII, including the activities they undertake, challenges they encounter and how their efforts could be enhanced. We used Qualitative Description to analyse transcripts and validated findings through participant feedback.ResultsWe identified four main areas of countering activities: (1) generating and compiling data and evidence, (2) accessing policymakers and restricting industry access, (3) working with media and (4) engaging in a national coalition. Each area was linked to challenges, including (1) lack of data, (2) no/weak implementation of FCTC Article 5.3, (3) industry ties with media professionals and (4) advocates’ limited capacity. To address these challenges, participants suggested initiatives, including access to country-specific data, building advocates’ skills in compiling and using such data in research and monitoring, and in coalition development; others aiming at training journalists to question and investigate TII; and finally, diverse interventions intended to advance a whole-of-government approach to tobacco control. Structural changes to tobacco control funding and coordination were suggested to facilitate the proposed measures.ConclusionThis research highlights that following years of investment in tobacco control in LMICs, there is growing confidence in addressing TII. We identify straightforward initiatives that could strengthen such efforts. This research also underscores that more structural changes to enhance tobacco control capacity building should be considered.

Sign in / Sign up

Export Citation Format

Share Document