Validation of a Bitumen Oxidation Rate Model

2017 ◽  
Vol 2632 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Philip Herrington ◽  
Bryony James ◽  
Theuns F. P. Henning
Keyword(s):  
Product Formation ◽  
Practical Significance ◽  
Hydroxyl Group ◽  
Slow Reaction ◽  
Chip Seal ◽  
Asphalt Mix ◽  
Long Time ◽  
Short Time ◽  
Time Frames ◽  
Over Time

This paper reports on experiments aimed at validating a model for predicting the rate of oxidation of bitumen, in asphalt mix and chip seal road surfacings, over time periods of practical significance. Experiments were conducted in which bitumen films of varying thickness were oxidized in the field for 20 years and in the laboratory for up to 5.5 years. Bitumen oxidation in the laboratory was carried out at 50°C in air at atmospheric pressure and resulted in an extent of oxidation approximately equivalent to 11.5 years in the field. Oxidation of bitumen in the films was followed for changes in carbonyl, sulfoxide, and hydroxyl group concentrations measured by infrared spectroscopy, weight change, and viscosity. The data were fitted to an earlier derived rate equation based on a model in which the overall reaction was approximated as the sum of a fast and slow reaction. The model had been found to describe oxidation product formation very well over short time frames. The current work has shown that the model also applies over time frames (extents of oxidation) relevant to actual surfacing lives. A key assumption in the model that depletion of bitumen reactants in the slow reaction phase was negligible was also supported over long time frames. Both fast and slow phases of the reaction were found to be dependent on oxygen concentration, as assumed in the model. The oxygen dependence of the rate is discussed as a two-stage reaction mechanism previously described in the literature.

scholarly journals What Influences Customer Satisfaction When? Product and Service Over Time

2016 ◽  
Vol 8 (3) ◽  
pp. 45 ◽  
Author(s):  
Shueh-Chin Ting
Keyword(s):  
Customer Satisfaction ◽  
Service Performance ◽  
Customer Relationship ◽  
Long Time ◽  
Curvilinear Relationships ◽  
Short Time ◽  
Time Frames ◽  
Post Purchase ◽  
Product Weight ◽  
Over Time

<p>Though researchers have examined the changes in the effects of product and service performance on customer satisfaction, the short time frames of most studies prevents deeper understanding of this relationship. This study collects information from pre-purchase to 15 years post-purchase from 11,056 potential and existing automobile customers in the Taiwan market. The data is analyzed by a regression model. Results reveal that the importance of both product and service performance change over long time and the long-term trends of product and service performance weights are non-linear. In addition, from pre-purchase to the second year post-purchase, service weight is higher than product weight, but after the third year, product weight exceeds service weight. Product and service weight on customer satisfaction over time exhibit curvilinear relationships. Therefore, which one of product or service a company should stress depends on the stage in the customer relationship.</p>

A Linear Poroelastic Analysis of Time-Dependent Crack-Tip Fields in Polymer Gels

2018 ◽  
Vol 85 (11) ◽  
Author(s):  
Yalin Yu ◽  
Nikolaos Bouklas ◽  
Chad M. Landis ◽  
Rui Huang
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Tip ◽  
Polymer Gels ◽  
Time Limit ◽  
Time Limits ◽  
Long Time ◽  
Short Time ◽  
Over Time

Based on a linear poroelastic formulation, we present an asymptotic analysis of the transient crack-tip fields for stationary cracks in polymer gels under plane-strain conditions. A center crack model is studied in detail, comparing numerical results by a finite element method to the asymptotic analysis. The time evolution of the crack-tip parameters is determined as a result of solvent diffusion coupled with elastic deformation of the gel. The short-time and long-time limits are obtained for the stress intensity factor and the crack-tip energy release rate under different chemo-mechanical boundary conditions (immersed versus not-immersed, displacement versus load controlled). It is found that, under displacement-controlled loading, the crack-tip energy release rate increases monotonically over time for the not-immersed case, but for the immersed case, it increases first and then decreases, with a long-time limit lower than the short-time limit. Under load control, the energy release rate increases over time for both immersed and not-immersed cases, with different short-time limits but the same long-time limit. These results suggest that onset of crack growth may be delayed until the crack-tip energy release rate reaches a critical value if the applied displacement or traction is subcritical but greater than a threshold.

SCALE INVARIANCE IN SELECTIN-MEDIATED LEUKOCYTE ROLLING

Fractals ◽  
2004 ◽  
Vol 12 (02) ◽  
pp. 235-241 ◽  
Author(s):  
MICHAEL R. KING
Keyword(s):  
Time Series ◽  
Time Scales ◽  
Hurst Exponent ◽  
White Blood Cells ◽  
Spatial Arrangement ◽  
Range Analysis ◽  
Rescaled Range Analysis ◽  
Long Time ◽  
Short Time ◽  
Over Time

White blood cells slowly roll along the walls of blood vessels, due to the coordinated formation and breakage of chemical selectin-carbohydrate bonds. Using detailed computer simulations of cells rolling on a selectin surface under flow, we show the time series of the cell translational velocity to be fractal in nature over time scales ranging from 22–211 ms. A rescaled range analysis was performed to determine the Hurst exponent of the velocity time series, for simulations of cells rolling on either a uniform or punctate distribution of P-selectin molecules. The rolling behavior was found to exhibit two very distinct regimes, with a negative Hurst exponent ranging from -(1.2-0.6) over time scales of 23-27 ms, and a positive Hurst exponent of +0.47±0.03 over time scales of 27-211 ms. The short-time Hurst exponent was found to be a strong function of the molecular distribution and also a function of average molecular density, while the long-time Hurst exponent was unchanged over all conditions studied. The implication is that the short-time adhesive behavior of cells interacting with a reactive surface is sensitive to the spatial arrangement of molecules, and the total number of molecules on the surface.

Short-Time Tests for Long-Time Endurance

1923 ◽  
Vol 128 (4) ◽  
pp. 264-264
Author(s):  
J. W. Harsch
Keyword(s):  
Long Time ◽  
Short Time

Effect of Vial shaking on Loading Time of Epirubicin into Drug-Eluting Bead

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Kenji Ikeda ◽  
Yusuke Kawamura ◽  
Masahiro Kobayashi ◽  
Taito Fukushima ◽  
Yushi Sorin ◽  
...  
Keyword(s):  
Antitumor Agent ◽  
Loading Rates ◽  
Vortex Mixer ◽  
Long Time ◽  
Group A ◽  
Drug Eluting ◽  
Large Hepatocellular Carcinoma ◽  
Group B ◽  
Time Required ◽  
Short Time

Background: Although DC Bead has been useful in treatment of multiple and large hepatocellular carcinoma, loading time of doxorubicin into the DC Bead takes a long time of 30-120 minutes. Epirubicin is also used as an antitumor agent together with DC Bead, but its loading efficiency was not sufficiently elucidated. Methods: To shorten loading time of epirubicin into DC Bead (100-300µm, 300-500µm, 500-700µm), we examined the following three methods after mixing the drug: (a) let stand in room temperature, (b) agitated for 30 seconds with Vortex mixer, and (c) sonicated for 30 seconds with ultrasonic cleaner. After loading of epirubicin by each method, supernatant concentration for epirubicin was assayed at 5, 10, 30, 60, and 120 minutes. Results: Epirubicin loading rates for small bead (100-300µm) at 5 minutes were 82.9 % in group a, 93.8% in group b, and 79.9 % in group c. Similarly, medium bead (300-500µm), 40.1% in group a, 65.7% in group b and 45.5% in group c, respectively. In large-sized bead (500-700µm), loaded rates of epirubicin were 38.8% in group a, 59.0% in group b and 48.0% in group c. Agitation of mixture of epirubicin and DC Bead with Vortex mixer significantly shortened the loading time, but sonication did not affect the time required. Microscopic examination did not lead to any morphological change of microspheres in all the methods. Conclusions: Short time of agitation with Vortex mixer reduced the necessary time for loading of epirubicin in every standard of DC Bead.

Robust Test Method of TSOP PEMs for Space Application

2019 ◽  
Author(s):  
Yasunobu Iwai ◽  
Koichi Shinozaki ◽  
Daiki Tanaka
Keyword(s):  
Evaluation Method ◽  
Low Cost ◽  
Reliability Evaluation ◽  
Test Method ◽  
Thermal Shock Test ◽  
Space Application ◽  
Space Applications ◽  
Limit Test ◽  
Long Time ◽  
Short Time

Abstract Compared with space parts, consumer parts are highly functional, low cost, compact and lightweight. Therefore, their increased usage in space applications is expected. Prior testing and evaluation on space applicability are necessary because consumer parts do not have quality guarantees for space application [1]. However, in the conventional reliability evaluation method, the test takes a long time, and the problem is that the robustness of the target sample can’t be evaluated in a short time. In this report, we apply to the latest TSOP PEM (Thin Small Outline Package Plastic Encapsulated Microcircuit) an evaluation method that combines preconditioning and HALT (Highly Accelerated Limit Test), which is a test method that causes failures in a short time under very severe environmental conditions. We show that this method can evaluate the robustness of TSOP PEMs including solder connections in a short time. In addition, the validity of this evaluation method for TSOP PEM is shown by comparing with the evaluation results of thermal shock test and life test, which are conventional reliability evaluation methods.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

Team Communication Patterns in Critical Situations

2021 ◽  
pp. 155534342098665
Author(s):  
Floris van den Oever ◽  
Jan Maarten Schraagen
Keyword(s):  
Information Seeking ◽  
Communication Patterns ◽  
Team Communication ◽  
Communication Structures ◽  
Communication Processes ◽  
Event Model ◽  
Or Team ◽  
Short Time ◽  
Time Frames ◽  
Critical Situations

Teams operating in time-pressured, dynamic environments frequently need to cope with critical situations varying in complexity and hazard. To cope with critical situations, teams may have to adapt their communication processes. Adaptation of team communication processes has been studied mostly at short time frames (minutes). Literature on adapting communication at longer time frames is limited (hours, relative to minutes). We used the relational event model to compare team communication in critical and noncritical situations of pediatric cardiac surgeries and Apollo 13 flight director’s voice loops. Teams showed some flattening of communication structures in critical situations. Both teams maintained institutional roles and displayed closed-loop and information-seeking communication. Communication patterns may change further with increasing criticality. The exact way teams adapt to critical situations may differ depending on team, team size and situation. Findings may inform team training procedures or team structure development.

Alteration of intrapancreatic serotonin, homocysteine, TNF-α, and NGF levels as predisposing factors for diabetes following exposure to 900-MHz waves

2021 ◽  
pp. 074823372110226
Author(s):  
Gholamali Jelodar ◽  
Mansour Azimzadeh ◽  
Fatemeh Radmard ◽  
Narges Darvishhoo
Keyword(s):  
Cell Damage ◽  
Pancreatic Beta Cell ◽  
Predisposing Factors ◽  
Male Rats ◽  
Control Group ◽  
Predisposing Factor ◽  
Time Exposure ◽  
Tnf Α ◽  
Long Time ◽  
Short Time

Exposure to mobile phone radiation causes deleterious health effects on biological systems. The objects of this study were to investigate the effect of 900-MHz radiofrequency waves (RFW) emitted from base transceiver station antenna on intrapancreatic homocysteine (Hcy), tumor necrosis factor-α (TNF-α), and nerve growth factor (NGF) as predisposing factors involved in pancreatic beta cell damage. Thirty male rats (Sprague-Dawley, 200 ± 10 g) were randomly divided into the control (without any exposure) and exposed groups: short time (2 h/day), long time (4 h/day), and exposed to 900-MHz RFW for 30 consecutive days. On the last days of the experiment, animals were killed and pancreas tissue was dissected out for evaluation of serotonin, Hcy, TNF-α, and NGF. There was a significant decrease in the serotonin and NGF levels in the pancreatic tissue of exposed groups compared to the control group ( p < 0.05). Also, the levels of serotonin and NGF in the long-time exposure were significantly lower than the short-time exposure ( p < 0.05). However, levels of Hcy and TNF-α were significantly increased in the pancreas of exposed groups compared to the control groups ( p < 0.05). Exposure to 900-MHz RFW decreased pancreatic NGF and serotonin levels and increased the proinflammatory markers (Hcy and TNF-α), which can be a predisposing factor for type 2 diabetes.

scholarly journals Kinetic analysis and optimisation of 18F-rhPSMA-7.3 PET imaging of prostate cancer

2021 ◽  
Author(s):  
Simona Malaspina ◽  
Vesa Oikonen ◽  
Anna Kuisma ◽  
Otto Ettala ◽  
Kalle Mattila ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Metastatic Disease ◽  
Uptake Kinetics ◽  
Whole Body ◽  
Target Area ◽  
Post Injection ◽  
The Mean ◽  
Pet Radiopharmaceutical ◽  
Time Frames ◽  
Over Time

Abstract Purpose This phase 1 open-label study evaluated the uptake kinetics of a novel theranostic PET radiopharmaceutical, 18F-rhPSMA-7.3, to optimise its use for imaging of prostate cancer. Methods Nine men, three with high-risk localised prostate cancer, three with treatment-naïve hormone-sensitive metastatic disease and three with castration-resistant metastatic disease, underwent dynamic 45-min PET scanning of a target area immediately post-injection of 300 MBq 18F-rhPSMA-7.3, followed by two whole-body PET/CT scans acquired from 60 and 90 min post-injection. Volumes of interest (VoIs) corresponding to prostate cancer lesions and reference tissues were recorded. Standardised uptake values (SUV) and lesion-to-reference ratios were calculated for 3 time frames: 35–45, 60–88 and 90–118 min. Net influx rates (Ki) were calculated using Patlak plots. Results Altogether, 44 lesions from the target area were identified. Optimal visual lesion detection started 60 min post-injection. The 18F-rhPSMA-7.3 signal from prostate cancer lesions increased over time, while reference tissue signals remained stable or decreased. The mean (SD) SUV (g/mL) at the 3 time frames were 8.4 (5.6), 10.1 (7) and 10.6 (7.5), respectively, for prostate lesions, 11.2 (4.3), 13 (4.8) and 14 (5.2) for lymph node metastases, and 4.6 (2.6), 5.7 (3.1) and 6.4 (3.5) for bone metastases. The mean (SD) lesion-to-reference ratio increases from the earliest to the 2 later time frames were 40% (10) and 59% (9), respectively, for the prostate, 65% (27) and 125% (47) for metastatic lymph nodes and 25% (19) and 32% (30) for bone lesions. Patlak plots from lesion VoIs signified almost irreversible uptake kinetics. Ki, SUV and lesion-to-reference ratio estimates showed good agreement. Conclusion 18F-rhPSMA-7.3 uptake in prostate cancer lesions was high. Lesion-to-background ratios increased over time, with optimal visual detection starting from 60 min post-injection. Thus, 18F-rhPSMA-7.3 emerges as a very promising PET radiopharmaceutical for diagnostic imaging of prostate cancer. Trial Registration NCT03995888 (24 June 2019).

Sign in / Sign up

Export Citation Format

Share Document