scholarly journals Functional grading of viscoelastic defined hot mix asphalt layers

2020 ◽  
Vol 19 (3) ◽  
pp. 258-271
Author(s):  
Murat Bostancıoğlu ◽  
Keyword(s):  
Surface Layer ◽  
Fatigue Strength ◽  
Hot Mix Asphalt ◽  
Flexible Pavements ◽  
Field Studies ◽  
Real Field ◽  
Surface Layers ◽  
Mechanical Responses ◽  
Study Results

In the design of layered flexible pavements with the mechanistic-empirical (M-A) method, the material characterization of layers is critical for the correct calculation of mechanical responses. The surface layers of flexible pavements produced as hot mix asphalt (HMA) behave as a visco-elastic material under real field conditions. In this study, in which the HMA surface layer was defined viscoelastic by creep-compliance method, functional grading was applied to the surface layer at the same time to increase the fatigue strength of the pavement. Functional grading application was performed in the form of 3, 5, 7, and 9 sub-layers with linear and exponential functions. The pavement life values due to the mechanical responses that occurred in the pavement were determined by the Asphalt Institute and Shell methods. The study results show that the fatigue strength of the viscoelastic surface layer increases significantly as a result of functional grading. Especially in sections with exponential grading, an improvement of more than 10% was achieved even when a small number of sub-layers used. These results show that functional grading can also be successfully applied in field studies, and even with three sub-layers, significant improvements can be provided

Characterization of nanocrystalline surface layer induced by shot peening and effect on their fatigue strength.

2004 ◽  
Vol 843 ◽  
Author(s):  
Hideo Mano ◽  
Kondo Satoru ◽  
Akihito Matsumuro ◽  
Toru Imura
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Fatigue Strength ◽  
Vickers Hardness ◽  
Shot Peening ◽  
White Layer ◽  
The Other ◽  
Fatigue Properties ◽  
Nanocrystalline Layer

ABSTRACTThe shot peening process is known to produce a hard layer, known as the white layer” on the surface of coil springs. However, little is known about the fatigue properties of this white-layer.In this study, coil springs with a white-layer were manufactured. The surface of these springs was then examined using micro Vickers hardness, FE-SEM etc. to test fatigue strength of the springs.From the results obtained, a microstructure of the white-layer with grain size of 50–100 nm was observed, with a Vickers hardness rating of 8–10 GPa.Tow category springs were manufactured utilizing a double-peening process. These springs had the same residual stress destruction and surface roughness. Only one difference was observed: one spring had a nanocrystalline layer on the surface, while the other did not. The results of the fatigue test realized an increase in the fatigue life of the nanocrystalline surface layer by 9%.

scholarly journals Theory and practice of fatigue strength technological support in machinery

2018 ◽  
Vol 2018 (10) ◽  
pp. 38-42 ◽  
Author(s):  
Анатолий Тотай ◽  
Anatoliy Totay
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Surface Layer ◽  
Fatigue Strength ◽  
Theory And Practice ◽  
Surface Layers ◽  
Technological Support ◽  
Dislocations Density ◽  
Temperature Factors

On a basis of the theory of metal plastic deformation there are determined analytical ties between speed, power and temperature factors of machining with parameters of machinery surface layers defining their resistance to fatigue destructions. The paper reports the technological assurance options for resistance to fatigue by means of the control of such surface layer state parameters of machinery as dislocations density and a grain size of structure material.

Immunochemical Characterization of Setaria cervi Microfilarial Antigens Using Novel Antibodies

2019 ◽  
Vol 19 (14) ◽  
pp. 1263-1274 ◽  
Author(s):  
Anuradha Kalani ◽  
Komal Kalani ◽  
Poonam Chaturvedi ◽  
Pankaj Chaturvedi
Keyword(s):  
Adult Worm ◽  
Diagnostic Tests ◽  
Protective Immunity ◽  
Complex Nature ◽  
Immune Recognition ◽  
Setaria Cervi ◽  
Crossed Immunoelectrophoresis ◽  
Study Results ◽  
Immune Rabbit

Background:Filariasis affects millions of people in tropical and subtropical regions of the world and is caused by nematode roundworm. In order to develop a vaccine and specific diagnostic tests, it is important to characterize different stages of the filarial worms. Microfilariae (Mf) stage of the roundworm is found in host’s blood or lymph vessels and can be important not only for developing better immunodiagnostics but also for understanding immune recognition and its relevance to immunepathogenesis and protective immunity.Objective:The present study aimed to immunocharacterize Mf and adult worm antigens that could be helpful in future diagnostic tests.Method:Four different immune sera against Setaria cervi intact live, intact live with adjuvant, intact glutaraldehyde fixed with adjuvant and total somatic Mf were prepared and used for the immunocharacterization of Mf antigens.Results:Our study results suggest that compared to fixed intact Mf, live intact Mf are more immunogenic, as the immune sera generated against intact live Mf showed high ELISA reactivity with Setaria cervi Mf and adult worm antigens. All the four immune sera IgG fractions had surface specificity as determined through considerable ELISA reactivity with S. cervi intact Mf. When tested under native conditions (immunoelectrophoresis and crossed immunoelectrophoresis), all the four immune rabbit sera were able to detect antigens of S. cervi Mf and adult stages.Conclusion:These results can be useful in detailed understanding of the complex nature of the Mf and adult antigens, which are prerequisites in the development of vaccine and more specific diagnostic tests.

scholarly journals Design and Characterization of Microscale Auxetic and Anisotropic Structures Fabricated by Multiphoton Lithography

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 446
Author(s):  
Ioannis Spanos ◽  
Zacharias Vangelatos ◽  
Costas Grigoropoulos ◽  
Maria Farsari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Mechanical Responses ◽  
Multiphoton Lithography ◽  
Anisotropic Structures ◽  
Scanning Electron

The need for control of the elastic properties of architected materials has been accentuated due to the advances in modelling and characterization. Among the plethora of unconventional mechanical responses, controlled anisotropy and auxeticity have been promulgated as a new avenue in bioengineering applications. This paper aims to delineate the mechanical performance of characteristic auxetic and anisotropic designs fabricated by multiphoton lithography. Through finite element analysis the distinct responses of representative topologies are conveyed. In addition, nanoindentation experiments observed in-situ through scanning electron microscopy enable the validation of the modeling and the observation of the anisotropic or auxetic phenomena. Our results herald how these categories of architected materials can be investigated at the microscale.

scholarly journals Chemical Durability of Glass Containing Srp Waste - Leachability Characteristics, Protective Layer Formation, and Repository System Interactions

1981 ◽  
Vol 11 ◽  
Author(s):  
George G. Wicks ◽  
Barbara M. Robnett ◽  
W. Duncan Rankin
Keyword(s):  
Protective Layer ◽  
Layer Formation ◽  
Surface Layers ◽  
Waste Products ◽  
Safety And Reliability ◽  
Experimental Findings ◽  
Nuclear Waste Forms ◽  
Leaching Models ◽  
Surface Layer Formation

Leachability is one of the most important properties of solidified nuclear waste forms because it provides information on the performance and the subsequent safety and reliability that the waste products will possess. One of the most important experimental findings in the leachability field has been the discovery and subsequent detailed characterization of protective surface layers that form on waste glass during leaching. These layers can have a beneficial effect on product performance while in storage by improving productdurability with time. As a result of surface layer formation and the effects on subsequent product leaching characteristics, new qualitative and quantitative leaching models have recently been proposed.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

Electrokinetics, Adsorption and Colloid Study of Simulated Nuclear Waste Glasses Leached in Aqueous Solutions

1984 ◽  
Vol 44 ◽  
Author(s):  
Cheng T. Lee ◽  
D. E. Clark
Keyword(s):  
Surface Layer ◽  
Nuclear Waste ◽  
Glass Surface ◽  
Charged Particles ◽  
Electrostatic Repulsion ◽  
Surface Layers ◽  
Short Term ◽  
Chloride Solutions ◽  
Zeta Potentials ◽  
Glass Surfaces

AbstractZeta potentials of SRL-131-29.8% TOS simulated nuclear waste glasses leached in D.I. water, Al, Ca, Mg, and Zn chloride solutions at 90°C were measured as a function of leaching time. For short term leaching, the adsorption of Ca, Mg, Zn and Al reverses the glass surface potential from negative to positive. Colloids were found to be stable in D.I. water and AICl3 solutions after leaching, presumably due to the electrostatic repulsion between the glass surface and similarly charged particles. Colloids were not found in Mg, Zn or Ca chloride solutions after leaching; instead, a relatively thick metasilicate surface layer was formed on glass surfaces leached in these solutions. The concentration of Si in solution is reduced by the formation of these surface layers.

scholarly journals Delineating shallow Neogene deformation structures in northeastern Pará State using Ground Penetrating Radar

2003 ◽  
Vol 75 (2) ◽  
pp. 235-248 ◽  
Author(s):  
Dilce F. Rossetti
Keyword(s):  
Ground Penetrating Radar ◽  
Structural Models ◽  
Field Studies ◽  
Strike Slip ◽  
Brittle Deformation ◽  
Shallow Subsurface ◽  
Deformation Structures ◽  
Ground Penetrating ◽  
Slip Motion

The geological characterization of shallow subsurface Neogene deposits in northeastern Pará State using Ground Penetrating Radar (GPR) revealed normal and reverse faults, as well as folds, not yet well documented by field studies. The faults are identified mostly by steeply-dipping reflections that sharply cut the nearby reflections causing bed offsets, drags and rollovers. The folds are recognized by reflections that are highly undulating, configuring broad concave and convex-up features that are up to 50 m wide and 80 to 90 ns deep. These deformation structures are mostly developed within deposits of Miocene age, though some of the faults might continue into younger deposits as well. Although the studied GPR sections show several diffractions caused by trees, differential degrees of moisture, and underground artifacts, the structures recorded here can not be explained by any of these ''noises''. The detailed analysis of the GPR sections reveals that they are attributed to bed distortion caused by brittle deformation and folding. The record of faults and folds are not widespread in the Neogene deposits of the Bragantina area. These GPR data are in agreement with structural models, which have proposed a complex evolution including strike-slip motion for this area from the Miocene to present.

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