scholarly journals Impact of temperature on short- and long-term aging of asphalt binders

2016 ◽  
Vol 1 ◽  
pp. 6 ◽  
Author(s):  
Lily D. Poulikakos ◽  
Bernhard Hofko ◽  
Laurent Porot ◽  
Xiaohu Lu ◽  
Hartmut Fischer ◽  
...  
Keyword(s):  
Softening Point ◽  
Mechanical Characterization ◽  
Chemical Characterization ◽  
Effect Of Temperature ◽  
Specimen Preparation ◽  
Structural Level ◽  
Short Term ◽  
Needle Penetration ◽  
Reduced Temperature

Properties of asphalt concrete after aging are important parameters in determining the long-term performance of these materials. With the popularity of reduced temperature mixtures the question remains how this reduced temperature in short-term aging affects the long-term properties. This paper focuses on developing a robust and fundamental understanding of the effect of temperature on aging by connecting the chemistry of bitumen to its mechanics. To this end, round robin experiments are being currently conducted within 8 laboratories using four binders of the same grade 70/100 pen from different crude sources. In developing chemo-mechanical characterization techniques at the nano- and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature needs to be taken into consideration. Furthermore, the development of uniform specimen preparation procedures for these bituminous materials at the nano- and micro-structural level is the focus. The chemical characterization is performed using Fourier transform infrared spectroscopy (FTIR). For the mechanical characterization rheological data is used using the dynamic shear rheometer (DSR) as well as conventional tests, e.g. needle penetration and softening point using the ring and ball method. It is shown that the short-term aging temperature affects the increase in softening point, while the consequent effect on long term aging is less pronounced.

scholarly journals Impact of temperature on short- and long-term aging of asphalt binders

2016 ◽  
Vol 1 ◽  
pp. 6
Author(s):  
Lily D. Poulikakos ◽  
Bernhard Hofko ◽  
Laurent Porot ◽  
Xiaohu Lu ◽  
Hartmut Fischer ◽  
...  
Keyword(s):  
Softening Point ◽  
Mechanical Characterization ◽  
Chemical Characterization ◽  
Effect Of Temperature ◽  
Specimen Preparation ◽  
Structural Level ◽  
Short Term ◽  
Needle Penetration ◽  
Reduced Temperature

Properties of asphalt concrete after aging are important parameters in determining the long-term performance of these materials. With the popularity of reduced temperature mixtures the question remains how this reduced temperature in short-term aging affects the long-term properties. This paper focuses on developing a robust and fundamental understanding of the effect of temperature on aging by connecting the chemistry of bitumen to its mechanics. To this end, round robin experiments are being currently conducted within 8 laboratories using four binders of the same grade 70/100 pen from different crude sources. In developing chemo-mechanical characterization techniques at the nano- and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature needs to be taken into consideration. Furthermore, the development of uniform specimen preparation procedures for these bituminous materials at the nano- and micro-structural level is the focus. The chemical characterization is performed using Fourier transform infrared spectroscopy (FTIR). For the mechanical characterization rheological data is used using the dynamic shear rheometer (DSR) as well as conventional tests, e.g. needle penetration and softening point using the ring and ball method. It is shown that the short-term aging temperature affects the increase in softening point, while the consequent effect on long term aging is less pronounced.

Influence of temperature on the activity of anammox granular biomass

2016 ◽  
Vol 73 (10) ◽  
pp. 2518-2525 ◽  
Author(s):  
D. Sobotka ◽  
K. Czerwionka ◽  
J. Makinia
Keyword(s):  
Removal Rate ◽  
Batch Reactor ◽  
Effect Of Temperature ◽  
Short Term ◽  
Temperature Range ◽  
Batch Tests ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Granular Biomass

The aim of this study was to determine a short-term and long-term effect of temperature on the anammox rate and determination of temperature coefficients in the Arrhenius and Ratkowsky equations. The short-term effects of temperature on the anammox granular biomass were investigated in batch tests at ten different temperatures in the range of 10–55 °C. The maximum overall nitrogen removal rate of 1.3 gN gVSS−1·d−1 was observed at 40 °C (VSS: volatile suspended solids). The minimum rate, close to 0 gN gVSS−1·d−1, was observed for the limits of the analyzed temperature range (10 and 55 °C). The activity tests carried out at 55 °C showed an irreversible loss of the activity due to the observed biomass lysis. Subsequently to the batch tests, a sequencing batch reactor (SBR) was operated at different temperatures (from 30 to 11 °C) to determine the long-term effects of temperature. The system was successfully operated at 15 °C, but when temperature was decreased to 11 °C, nitrite started to accumulate and the system lost its stability. The temperature coefficient (θ) was 1.07 for the batch tests carried out in the temperature range of 10–40 °C. In contrast, during the long-term SBR operation, substantially different θ had to be estimated for two temperature ranges, 1.07 (T = 15–30 °C) and 1.65 (T = 11–15 °C).

Nitrification with Biofilms on Small Suspended Particles in Airlift Reactors

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2207-2211 ◽  
Author(s):  
L. Tijhuis ◽  
M. C. M. van Loosdrecht ◽  
J. J. Heijnen
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Term Effect ◽  
Effect Of Temperature ◽  
Nitrification Rate ◽  
Activated Sludge Process ◽  
Short Term ◽  
Long Term Effect ◽  
N Loading

The development of nitrifying biofilms and short and long term influences on the nitrification process were studied in a Biofilm-Airlift-Suspension-reactor. The studied changes are (i) startup of nitrification reactor at different dilution rates, (ii) the effect of temperature on N-oxidation capacity, (iii) the short term effect of N-loading rate on conversion to determine the nitrification overcapacity and (iv) long term effect of N-loading rate on conversion to determine the maximum nitrification capacity in this reactor system. It is shown that the specific nitrification capacity during start-up is constant, 1 g N/(gorg.mat. d), which is high compared to the activated sludge process. The influence of the temperature on the nitrification rate is much less than can be expected from pure culture experiments. On a short term there is only a small nitrification overcapacity in the reactor. The maximum nitrification rate during these experiments was 6 kg N/(m3 d), which is very high compared to the activated sludge process.

scholarly journals The Effect of Addition of Antioxidant 1,2-dihydro-2,2,4-trimethyl-quinoline on Characteristics of Crepe Rubber Modified Asphalt in Short Term Aging and Long Term Aging Conditions

2020 ◽  
Vol 10 (20) ◽  
pp. 7236
Author(s):  
Bahruddin Ibrahim ◽  
Arya Wiranata ◽  
Alfian Malik
Keyword(s):  
Weight Loss ◽  
Natural Rubber ◽  
Softening Point ◽  
Total Sample ◽  
Short Term ◽  
Modified Asphalt ◽  
Before And After ◽  
Aging Conditions ◽  
Asphalt Performance

The use of natural rubber to resist bitumen is usually prone to degradation and aging. One method to overcome this problem is the addition of antioxidants. This study aims to determine the effect of the addition of antioxidants 1,2-dihydro-2,2,4-trimethyl-quinoline (TMQ) on natural rubber modified asphalt crepe rubber and its performance in short-term and long-term aging conditions. The modified rubber asphalt mixture’s manufacture begins by melting the crepe rubber at 200 °C before being mixed in asphalt at 165 °C. Addition of antioxidant TMQ during the stirring process of the mixture of asphalt and melted rubber. The crepe rubber content was 8, 10, and 12% w/w, while the TMQ content was 1, 2, and 3% w/w of the total sample weight. The modified asphalt samples’ characterization included penetration, softening point, weight loss after a rolling thin film oven test (RTFOT), penetration after RTFOT, and Marshall test. Review of the performance of asphalt under short-term aging conditions using a dynamic shear rheometer (DSR). Evaluation of asphalt performance under long-term aging conditions using Fourier-transform infrared spectroscopy (FTIR). The results showed that the fact that the best-modified asphalt product was the addition of 10% crepe rubber and 2% TMQ. The best-modified asphalt characteristics have penetration 68.70 dmm, softening point 55.45 °C, weight loss only 0.0579%, penetration after RTFOT 59.60, Marshall stability 1403.96 kg with optimum asphalt content of 5.50%, and rutting factor (G*/Sinδ) 6.91 kPa and 16.1 kPa before and after RTFOT. Overall, the modified crepe rubber asphalt can improve the performance of the asphalt in terms of durability. Simultaneously, the antioxidant TMQ works very well in increasing the resistance of bitumen to aging in the conditions of short-term aging and long-term aging.

scholarly journals Putative Silicon Transporters and Effect of Temperature Stresses and Silicon Supplementation on Their Expressions and Tissue Silicon Content in Poinsettia

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 569
Author(s):  
Jiangtao Hu ◽  
Yali Li ◽  
Byoung Ryong Jeong
Keyword(s):  
Expression Patterns ◽  
Dry Weight ◽  
Effect Of Temperature ◽  
Uptake Capacity ◽  
Short Term ◽  
Temperature Stresses ◽  
Citrate Transporter ◽  
Transporter Family ◽  
Si Content

Silicon (Si) is a beneficial element for plants. To understand Si uptake and accumulation in poinsettia, the Si transporters and their expression patterns were investigated. Nodulin 26-like intrinsic membrane proteins (NIPs) act as transporters of water and small solutes, including silicic acid. In this study, one NIP member, designated EpLsi1, was identified. Additionally, a protein from the citrate transporter family, designated EpLsi2, was identified. Sequence analyses indicated that EpLsi1 belonged to the NIP-I subgroup, which has a low Si uptake capacity. Consistently, the measured tissue Si content in the poinsettia was less than 1.73 ± 0.17 mg·g−1 dry weight, which was very low when compared to that in high Si accumulators. The expressions of EpLsi1 and EpLsi2 in poinsettia cuttings treated with 0 mg·L−1 Si decreased under temperature stresses. A short-term Si supplementation decreased the expressions of both EpLsi1 and EpLsi2 in the roots and leaves, while a long-term Si supplementation increased the expression of EpLsi1 in the leaves, bracts, and cyathia, and increased the expression of EpLsi2 in the roots and leaves. Tissue Si content increased in the roots of cuttings treated with 75 mg·L−1 Si at both 4 and 40 °C, indicating that the transport activities of the EpLsi1 were enhanced under temperature stresses. A long-term Si supplementation increased the tissue Si content in the roots of poinsettia treated with 75 mg·L−1 Si. Overall, poinsettia was a low Si accumulator, the expressions of Si transporters were down-regulated, and the tissue Si content increased with temperature stresses and Si supplementation. These results may help the breeding and commercial production of poinsettia.

scholarly journals Adding Structure to Statistics: A Study on COVID-19 Dynamics in India

2020 ◽  
Author(s):  
Arundhati Dixit ◽  
Sarthak Vishnoi ◽  
Sourabh Bikas Paul
Keyword(s):  
Fixed Effects ◽  
Policy Implications ◽  
Effect Of Temperature ◽  
Structural Vector Autoregression ◽  
Fixed Effects Model ◽  
Impulse Responses ◽  
Short Term ◽  
Compartmental Modelling ◽  
Structural Vector

This study pertains to COVID-19 in India, and begins by uncovering the statistical relationship between three time series-number of cases, number of deaths, and number of tests each day, using structural vector autoregression. Further, impulse responses of the before-mentioned series are studied. Effect of temperature and humidity on number of cases is analysed using the fixed effects model on city-level panel data. The next model utilises exponential smoothing for forecasting and conjecture for identifying peak specific to this data is presented. Lastly, multiple iterations of compartmental modelling, possible scenarios, and effect of underlying assumptions is analysed. The models are used to forecast number of cases (regression for short term and epidemiological for long term). In the end, policy implications of different modelling exercises and ways to check the implication for policy planning are discussed.

On the Effect of Temperature on Tightening Characteristics of Gaskets

2002 ◽  
Author(s):  
Jaroslav Bartonicek ◽  
Manfred Schaaf ◽  
Friedrich Schoeckle
Keyword(s):  
Room Temperature ◽  
Sheet Material ◽  
Leak Rate ◽  
Effect Of Temperature ◽  
Short Term ◽  
Hydraulic Test ◽  
Aging Period ◽  
Heating Device ◽  
Temperature Exposure

To study the effect of temperature on the tightening characteristics of gaskets, leak rate tests were performed using a servo-hydraulic test equipment (short term temperature exposure). According to the tests the tightening behaviour of gaskets made of fibre based sheet material improved with temperature due to additional deformation of the gaskets during the test. In tests with camprofile gaskets with graphite layers there was no significant additional deformation of the gasket thus the leak rates showed no difference between room temperature and elevated temperature. Regarding long term exposure to temperature it is expected that with a lot of gasket materials the leak rates increase after a certain aging period. It is too expensive to study these effects with complex servo-hydraulic test rigs. Therefore a more simple test rig was developed that can be loaded in hydraulic test rigs (to determine leak rate vs. gasket stress curves) and that can be exposed to temperature in an oven or by a special heating device.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Comparison of Auditory, Language, Memory, and Attention Abilities in Children With and Without Listening Difficulties

2020 ◽  
Vol 29 (4) ◽  
pp. 710-727
Author(s):  
Beula M. Magimairaj ◽  
Naveen K. Nagaraj ◽  
Alexander V. Sergeev ◽  
Natalie J. Benafield
Keyword(s):  
Auditory Processing ◽  
Short Term Memory ◽  
Group Differences ◽  
Long Term Memory ◽  
Short Term ◽  
Significant Group ◽  
Term Memory ◽  
Memory And Attention ◽  
Speed And Accuracy

Objectives School-age children with and without parent-reported listening difficulties (LiD) were compared on auditory processing, language, memory, and attention abilities. The objective was to extend what is known so far in the literature about children with LiD by using multiple measures and selective novel measures across the above areas. Design Twenty-six children who were reported by their parents as having LiD and 26 age-matched typically developing children completed clinical tests of auditory processing and multiple measures of language, attention, and memory. All children had normal-range pure-tone hearing thresholds bilaterally. Group differences were examined. Results In addition to significantly poorer speech-perception-in-noise scores, children with LiD had reduced speed and accuracy of word retrieval from long-term memory, poorer short-term memory, sentence recall, and inferencing ability. Statistically significant group differences were of moderate effect size; however, standard test scores of children with LiD were not clinically poor. No statistically significant group differences were observed in attention, working memory capacity, vocabulary, and nonverbal IQ. Conclusions Mild signal-to-noise ratio loss, as reflected by the group mean of children with LiD, supported the children's functional listening problems. In addition, children's relative weakness in select areas of language performance, short-term memory, and long-term memory lexical retrieval speed and accuracy added to previous research on evidence-based areas that need to be evaluated in children with LiD who almost always have heterogenous profiles. Importantly, the functional difficulties faced by children with LiD in relation to their test results indicated, to some extent, that commonly used assessments may not be adequately capturing the children's listening challenges. Supplemental Material https://doi.org/10.23641/asha.12808607

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