Quantitative Field Evaluation and Effectiveness of Fine Mix Under Hot-Mix Asphalt Base in Flexible Pavements

2003 ◽  
Vol 1823 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Imad L. Al-Qadi ◽  
Amara Loulizi ◽  
Samer Lahouar ◽  
Gerardo W. Flintsch ◽  
Thomas E. Freeman
Keyword(s):  
Compressive Stress ◽  
Hot Mix Asphalt ◽  
Flexible Pavements ◽  
Field Evaluation ◽  
Base Layer ◽  
Transverse Strain ◽  
Compressive Stresses ◽  
Different Temperatures ◽  
Transverse Strains

Testing was conducted with the main objective of predicting the effect of incorporating a fine hot-mix asphalt (HMA) layer under an HMA base on the long-term fatigue performance of flexible pavements. Testing at the Virginia Smart Road allowed the determination of the vertical compressive stress and horizontal transverse strain induced by a steering-axle tire of 25.8 kN (5,800 lb) under the HMA layer of two pavement designs, one of which included a fine surface mix below a base mix. Stresses and strains were measured for four different speeds [8, 24, 40, and 72 km/h (5, 15, 25, and 45 mph)], for three tire inflation pressures [552, 655, and 724 kPa (80, 95, and 105 psi)], and at different temperatures. Stresses were measured with pressure cells, while strains were measured with H-type strain gauges embedded in the HMA layers during construction. As expected, temperature was found to significantly affect the vertical compressive stresses and horizontal transverse strains measured under the HMA layer. Speed, on the other hand, did not affect the magnitude of the vertical compressive stress measured in any of the layers but did affect the loading time. However, speed was found to significantly affect the horizontal transverse strain measured under the HMA layer. The compressive stress and horizontal transverse strain measured at the bottom of the HMA layer at depths greater than 150 mm (6 in.) were found to be independent of tire inflation pressure ranges from 552 to 724 kPa (80 to 105 psi). It appears that incorporation of a fine HMA at the bottom of a HMA base layer would increase the fatigue lives of flexible pavements.

Closed-Form Solutions for Code Case 2286 Allowable Compressive Stresses Analogous to Vacuum Chart Method

2012 ◽  
Author(s):  
Harsh Kumar Baid ◽  
Donald LaBounty ◽  
Amiya Chatterjee
Keyword(s):  
Closed Form ◽  
Compressive Stress ◽  
Pressure Vessels ◽  
Closed Form Solutions ◽  
Compressive Stresses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
User Friendly

The allowable compressive stresses in pressure vessels can be calculated either from ASME Section VIII Division 1, Paragraph UG-28 vacuum chart method [2] or Code Case 2286 [1]. Code Case 2286 has been incorporated into ASME Section VIII Division 2, Part 5. For Division 1 vessels, the vacuum chart method is a user-friendly tool for determining allowable compressive stress. In this paper, the authors present the development of allowable compressive stress data based on closed-form solutions of Code Case 2286. These closed-form solutions yield exact allowable compressive stress values which are not influenced by any kind of sensitivity. The development presented in the paper is also user-friendly, similar to the vacuum chart, for the determination of allowable compressive stresses. These designs, based on Code Case 2286, are economical without any compromise in the safety of the pressure vessel. Examples are included to demonstrate the results.

scholarly journals New Aspects in the Mechanical Behavior of a Polycarbonate Found by an Experimental Study

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Alfredo Alán Rey Calderón ◽  
Alberto Díaz Díaz
Keyword(s):  
Mechanical Behavior ◽  
Axial Strain ◽  
Strain Curve ◽  
Uniaxial Tensile ◽  
Creep Recovery ◽  
Transverse Strain ◽  
Key Aspects ◽  
Transverse Strains ◽  
Compressive Tests

The aim of this paper was to analyze in detail the mechanical behavior of a polycarbonate by means of uniaxial tensile and compressive tests and to reveal new key aspects that must be taken into account in any predictive model. Uniaxial monotonic and creep-recovery tests were carried out at a variety of temperatures, stress levels, and load rates to get a complete description of the material response. Prior to mechanical testing, the material was subjected to a thermal rejuvenation in order to eliminate any previous aging and to obtain reliable and useful results. In every test, a complete determination of the strain state was assured by measuring axial and transverse strains with strain gauges. During the tests, significant asymmetry effects and viscous phenomena already reported by other authors were confirmed. The newest finding is that a nonlinear master transverse strain/axial strain curve matches perfectly with the experimental curves. This master curve is temperature- and rate-independent. Another originality of this paper is the disclosure of an instantaneous, hypoelastic-like behavior at high strain rates. The experimental observations presented in this study should be incorporated by a theoretical model whose aim is to accurately predict the mechanical behavior of polycarbonate subjected to any 3D stress state.

Quantitative Assessment of Soluble Fibrin in Plasma by Affinity Chromatography – A Comparative Study with desAA-Fibrin, desAABB-Fibrin and Fibrinogen

1985 ◽  
Vol 54 (02) ◽  
pp. 533-538 ◽  
Author(s):  
Wilfried Thiel ◽  
Ulrich Delvos ◽  
Gert Müller-Berghaus
Keyword(s):  
Affinity Chromatography ◽  
Calcium Ions ◽  
Quantitative Assessment ◽  
Fluid Phase ◽  
Soluble Fibrin ◽  
Binding Characteristics ◽  
Different Temperatures ◽  
Immobilized Proteins ◽  
Sepharose 4B

SummaryA quantitative determination of soluble fibrin in plasma was carried out by affinity chromatography. For this purpose, desAA-fibrin and fibrinogen immobilized on Sepharose 4B were used at the stationary side whereas batroxobin-induced 125I-desAA-fibrin or thrombin-induced 125I-desAABB-fibrin mixed with plasma containing 131I-fibrinogen represented the fluid phase. The binding characteristics of these mixtures to the immobilized proteins were compared at 20° C and 37° C. Complete binding of both types of fibrin to the immobilized desAA-fibrin was always seen at 20° C as well as at 37° C. However, binding of soluble fibrin was accompanied by substantial binding of fibrinogen that was more pronounced at 20° C. Striking differences depending on the temperature at which the affinity chromatography was carried out, were documented for the fibrinogen-fibrin interaction. At 20° C more than 90% of the applied desAA-fibrin was bound to the immobilized fibrinogen whereas at 37° C only a mean of 17% were retained at the fibrinogen-Sepharose column. An opposite finding with regard to the tested temperature was made with the desAABB-fibrin. Nearly complete binding to insolubilized fibrinogen was found at 37° C (95%) but only 58% of the desAABB-fibrin were bound at 20° C. The binding patterns did not change when the experiments were performed in the presence of calcium ions. The opposite behaviour of the two types of soluble fibrin to immobilized fibrinogen at the different temperatures, together with the substantial binding of fibrinogen in the presence of soluble fibrin to insolubilized fibrin in every setting tested, devaluates affinity chromatography as a tool in the quantitative assessment of soluble fibrin in patients’ plasma.

"New Donors" in Czochralski Grown Silicon Annealed at T≥ 600°C under Compressive Stress

2005 ◽  
Vol 108-109 ◽  
pp. 181-186 ◽  
Author(s):  
Valentin V. Emtsev ◽  
Boris A. Andreev ◽  
Gagik A. Oganesyan ◽  
D.I. Kryzhkov ◽  
Andrzej Misiuk ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Compressive Stress ◽  
Reference Temperature ◽  
Enhancement Effect ◽  
Shallow Acceptor ◽  
Thermal Donor ◽  
Compressive Stresses ◽  
Heat Treated ◽  
Donor Formation ◽  
New Donors

Effects of compressive stress on oxygen agglomeration processes in Czochralski grown silicon heat treated at T= 450OC, used as a reference temperature, and T= 600OC to 800OC are investigated in some detail. Compressive stresses of about P= 1 GPa lead to enhanced formation of Thermal Double Donors in materials annealed over a temperature range of T= 450OC – 600OC. It has been shown that the formation of thermal donors at T= 450OC under normal conditions and compressive stress is accompanied with loss of substitutional boron. In contrast, the concentration of the shallow acceptor states of substitutional boron in silicon annealed under stress at T≥ 600OC remains constant. An enhancement effect of thermal donor formation is gradually weakened at T≥ 700OC. The oxygen diffusivity sensitive to mechanical stress is believed to be responsible for the observed effects in heat-treated silicon.

scholarly journals Determination of Load-Carrying Capacity of C-Profile Glued Ti-Al Column under Temperature Environment

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3013
Author(s):  
Leszek Czechowski
Keyword(s):  
Carrying Capacity ◽  
Tensile Tests ◽  
Discrete Models ◽  
Image Correlation ◽  
Load Carrying Capacity ◽  
Lagrange Equations ◽  
Load Carrying ◽  
Different Temperatures ◽  
Influence Of Temperature On

The paper deals with an examination of the behaviour of glued Ti-Al column under compression at elevated temperature. The tests of compressed columns with initial load were performed at different temperatures to obtain their characteristics and the load-carrying capacity. The deformations of columns during tests were registered by employing non-contact Digital Image Correlation Aramis® System. The numerical computations based on finite element method by using two different discrete models were carried out to validate the empirical results. To solve the problems, true stress-logarithmic strain curves of one-directional tensile tests dependent on temperature both for considered metals and glue were implemented to software. Numerical estimations based on Green–Lagrange equations for large deflections and strains were conducted. The paper reveals the influence of temperature on the behaviour of compressed C-profile Ti-Al columns. It was verified how the load-carrying capacity of glued bi-metal column decreases with an increase in the temperature increment. The achieved maximum loads at temperature 200 °C dropped by 2.5 times related to maximum loads at ambient temperature.

Determination of geometric properties of SNOM tips by means of combined far-field and near-field evaluation

1999 ◽  
Author(s):  
Soenke Seebacher ◽  
Wolfgang Osten ◽  
Werner P. O. Jueptner ◽  
Vadim P. Veiko ◽  
Nikolay B. Voznesensky
Keyword(s):  
Near Field ◽  
Field Evaluation ◽  
Far Field ◽  
Geometric Properties

scholarly journals THE EFFECTS ON BIOLOGICAL MATERIALS OF FREEZING AND DRYING BY VACUUM SUBLIMATION

1954 ◽  
Vol 100 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Donald Greiff ◽  
Henry Pinkerton
Keyword(s):  
Influenza Virus ◽  
Biological Materials ◽  
Continuous Operation ◽  
Virus Suspension ◽  
Vacuum Sublimation ◽  
End Point ◽  
Different Temperatures ◽  
Time Required

A vacuum sublimation apparatus is described which will permit, (a) the removal of water from virus suspensions at temperatures ranging down to –80°C., (b) continuous operation with a minimum of attention from the investigator, (c) sealing off of samples at operating pressures (10–5 mm. Hg), (d) simultaneous lyophilization of aliquot samples at different temperatures, (e) isolation of a portion of the apparatus without disturbing the remainder of the system, and (f) determination of the end-point of sublimation without disturbing the samples. The time required for drying 0.1 ml. of influenza virus suspension was shown to increase markedly with decrease of temperature, 8 days being required for dehydration at –80°C. in contrast to 2 days at –30°C. and 1 day at 0°C.

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