scholarly journals Laboratory Investigation of Aging Resistance for Rubberized Bitumen Modified by Using Microwave Activation Crumb Rubber and Different Modifiers

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4230
Author(s):  
Ben Zhang ◽  
Huaxin Chen ◽  
Honggang Zhang ◽  
Yongchang Wu ◽  
Dongliang Kuang ◽  
...  
Keyword(s):  
Fracture Energy ◽  
Elastic Recovery ◽  
Maximum Load ◽  
Crumb Rubber ◽  
Engineering Properties ◽  
Aging Condition ◽  
Short Term ◽  
Aging Resistance ◽  
Before And After

Different modification methods, such as adding modifiers and pretreating crumb rubber, have been developed to achieve decent engineering properties and reduce the viscosity of rubberized bitumen. This study evaluated the influence of the modification methods on the aging resistance for rubberized bitumen. Two types of crumb rubber—a 40-mesh crumb rubber and a microwave-pretreated crumb rubber—and two kinds of modifiers—Sasobit and Trans-polyoctenamer—were selected to prepare rubberized bitumen. The samples were subjected to a Thin-Film Oven Test for the simulation of the short-term aging condition, while a Pressure-Aging-Vessel test was used to simulate the long-term aging condition. The indexes of rubberized bitumen, including softening point, elastic recovery ratio, maximum load, ductility, fracture energy, phase angle, and dynamic modulus, were tested before and after aging. The result showed that trans-polyoctenamer displayed the best resistance to short-term aging, while Sasobit significantly improved the fracture energy of rubberized bitumen after short-term aging. Microwave pretreated partially destroyed the internal structure of crumb rubber, leading to a decrease of short-term aging resistance for rubberized bitumen. Compared with short-term aging, the changing trends of various indexes were basically same, except the discrepancy of properties indexes was reduced after long-term aging.

UV Aging Performance of Asphalt Containing LDHs

2014 ◽  
Vol 599 ◽  
pp. 265-270 ◽  
Author(s):  
Pan Fei Liu ◽  
Jun Zheng ◽  
Shao Peng Wu
Keyword(s):  
Aging Process ◽  
Complex Modulus ◽  
Short Term ◽  
Uv Aging ◽  
Oven Test ◽  
Aging Properties ◽  
Aging Resistance ◽  
Before And After ◽  
Double Hydroxides

In this paper the effect of Layered double hydroxides (LDHs) on aging properties of asphalts was studied. The thin film oven test TFOT tests and ultraviolet (UV) aging process were used to simulate short-term and long-term aging of asphalts, respectively. After aging, the physical properties and dynamic shear rheological behaviors of LDHs modified asphalts were investigated. The viscosity of LDHs modified asphalts was measured by Brookfield viscometer before and after UV aging. After UV aging, with an increase of LDHs, softening point and viscosity value of modified asphalts decreased, while both of ductility and penetration increased, compared to base asphalts. Temperature sweep tests showed that the complex modulus of LDHs modified asphalts was lower than that of base asphalt, while phase angle was higher. The results showed that LDHs improved the UV aging resistance of the asphalt, and it could prevent asphalt from UV aging.

scholarly journals Feasibility and Enjoyment of Exercise Video Games in Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 559-559
Author(s):  
Sara Freed ◽  
Briana Sprague ◽  
Lesley Ross
Keyword(s):  
Older Adults ◽  
Video Games ◽  
Game Design ◽  
Long Term Effects ◽  
Short Term ◽  
Qualitative And Quantitative ◽  
Before And After ◽  
Xbox Kinect ◽  
Game Developers

Abstract Interventions using exercise video games, or exergames, have shown short-term cognitive and physical benefits to older adults, though long-term effects are less promising. Enjoyment of exergames may promote exergame use after the intervention period, though little work has examined older adults’ views of exergames before and after gameplay experience. We invited 20 older adults between 65 and 84 years of age (M=73.30, SD=5.95) to play two Xbox Kinect games, Just Dance and Kinect Sports Rivals, for twenty minutes. In our presentation, we will present qualitative and quantitative findings of this pilot study, including findings that older adults reported that they were not likely to play similar exergames in the future and that they did not find the exergames to be more fun compared to other ways of exercising. We will discuss implications for game design and research relevant to game developers, manufacturers, and researchers. Part of a symposium sponsored by Technology and Aging Interest Group.

scholarly journals Endoscopically controlled surgery with open hemilaminectomy for the treatment of intradural extramedullary tumors: an operative technique and short-term outcomes of 20 consecutive cases

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaorong Yan ◽  
Huiqing Wang ◽  
Cai Li ◽  
Yuanxiang Lin ◽  
Lin Lin ◽  
...  
Keyword(s):  
Surgical Technique ◽  
Spinal Deformity ◽  
Tumor Recurrence ◽  
Clinical Symptoms ◽  
Short Term ◽  
Before And After ◽  
Intradural Extramedullary ◽  
Controlled Surgery

Abstract Background To present a surgical technique for the treatment of intradural extramedullary (IDEM) tumors by using endoscopically controlled surgery with open hemilaminectomy technique. Methods In this study, 20 patients with 22 IDEM tumors were enrolled. An endoscopically controlled surgery with open hemilaminectomy was employed to remove the tumors. Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis. Results All the tumors in 20 patients were well removed. The clinical symptoms were significantly reduced in all the patients as well. The short-term follow-up data showed that there was no tumor recurrence or spinal deformity. Conclusion The endoscopically controlled surgery with open hemilaminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors. It may be an effective surgical method for treating IDEM tumors. Larger samples and longer follow-up data are needed to verify its long-term effectiveness.

MULTIFRACTAL FLUCTUATIONS OF JIUZHAIGOU TOURISTS BEFORE AND AFTER WENCHUAN EARTHQUAKE

Fractals ◽  
2013 ◽  
Vol 21 (01) ◽  
pp. 1350001 ◽  
Author(s):  
KAI SHI ◽  
WEN-YONG LI ◽  
CHUN-QIONG LIU ◽  
ZHENG-WEN HUANG
Keyword(s):  
Wenchuan Earthquake ◽  
Moving Average ◽  
Long Term Memory ◽  
Short Term ◽  
Dynamical Mechanism ◽  
Before And After ◽  
Previous State ◽  
Multifractal Behavior ◽  
Multifractal Nature

In this work, multifractal methods have been successfully used to characterize the temporal fluctuations of daily Jiuzhai Valley domestic and foreign tourists before and after Wenchuan earthquake in China. We used multifractal detrending moving average method (MF-DMA). It showed that Jiuzhai Valley tourism markets are characterized by long-term memory and multifractal nature in. Moreover, the major sources of multifractality are studied. Based on the concept of sliding window, the time evolutions of the multifractal behavior of domestic and foreign tourists were analyzed and the influence of Wenchuan earthquake on Jiuzhai Valley tourism system dynamics were evaluated quantitatively. The study indicates that the inherent dynamical mechanism of Jiuzhai Valley tourism system has not been fundamentally changed from long views, although Jiuzhai Valley tourism system was seriously affected by the Wenchuan earthquake. Jiuzhai Valley tourism system has the ability to restore to its previous state in the short term.

scholarly journals Endoscopically-controlled surgery with open hemi-laminectomy for the treatment of intradural extramedullary tumors: An operative technique and short-term outcomes of 20 consecutive cases

2020 ◽  
Author(s):  
Xiaorong Yan ◽  
Huiqing Wang ◽  
Cai Li ◽  
Yuanxiang Lin ◽  
Lin Lin ◽  
...  
Keyword(s):  
Surgical Technique ◽  
Spinal Deformity ◽  
Tumor Recurrence ◽  
Clinical Symptoms ◽  
Short Term ◽  
Before And After ◽  
Intradural Extramedullary ◽  
Controlled Surgery

Abstract Background To present a surgical technique for the treatment of intradural extramedullary (IDEM) tumors by using endoscopically-controlled surgery with open hemi-laminectomy technique. Methods In this study, 20 patients with 22 IDEM tumors were enrolled. An endoscopically-controlled surgery with open hemi-laminectomy was employed to remove the tumors. Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis. Results All the tumors in 20 patients were well removed. The clinical symptoms were significantly reduced in all the patients as well. The short term follow-up data showed that there was no tumor recurrence or spinal deformity. Conclusion The endoscopically-controlled surgery with open hemi-laminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors. It may be an effective surgical method for treating IDEM tumors. Larger samples and longer follow-up data are needed to verify its long-term effectiveness.

scholarly journals COMPARATIVE ANALYSIS OF LOW TEMPERATURE RESISTANCE FOR NANOCARBON AND OTHER BITUMENS

2020 ◽  
Vol 5 (443) ◽  
pp. 89-96
Author(s):  
Zhurinov M.Zh., ◽  
◽  
Teltayev B.B., ◽  
Kalybay A.A., ◽  
Rossi C.O., ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Low Temperature ◽  
Polyphosphoric Acid ◽  
Crumb Rubber ◽  
Petrochemical Plant ◽  
Short Term ◽  
Temperature Resistance ◽  
Coal Rock ◽  
Low Temperature Resistance

A comparative analysis of the low temperature resistance for a nanocarbon bitumen and other 30 neat and modified bitumens has been performed in the work. The stiffness at the temperatures of -24°С, -30°С and -36°С under technical system Superpave has been accepted as an indicator of low temperature resistance of the bitumens. The stiffness of the bitumens has been determined on a bending beam rheometer (standard ASTM D 6648-08). Before testing the bitumens have been subjected to the double artificial aging: short-term aging – under standard AASHTO Т 240-13 and long-term aging – under standard ASTM D 6521-08. The nanocarbon bitumen has been prepared in the laboratory of the Kazakhstan Highway Research Institute (KazdorNII) with the use of a road bitumen of the grade BND 70/100 produced by the Pavlodar petrochemical plant (PNHZ) and a nanocarbon powder (2% by weight) manufactured from a coal rock of the deposit “Saryadyr” “Corporation “ON-Olzha” LLP, Akmola region, Kazakhstan). The nanocarbon powder (150-200 nm) has been manufactured by three-stage size reduction of the coal rock: I – a mechanical dispergator (up to 2-3 mm), II – an aerodynamic mill (up to 20 mcm), III – a reactor with a rotating electromagnetic field. The neat bitumens of the grades BND 50/70, BND 70/100, BND 100/130 have been produced by the plants of Kazakhstan and Russia; they satisfy the requirements of the standard ST RK 1373-2013. The modified bitumens have been prepared in the laboratory of KazdorNII with the use of the neat bitumens, 7 types of the polymers, crumb rubber and polyphosphoric acid and they satisfy the requirements of the standard ST RK 2534-2014. It has been determined that the nanocarbon bitumen is one of the most resistant at the low temperatures: -24°С, -30°С and -36°С.

scholarly journals Predicting the cumulative medical load of COVID-19 outbreaks after the peak in daily fatalities

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0247272
Author(s):  
Claudius Gros ◽  
Roser Valenti ◽  
Lukas Schneider ◽  
Benedikt Gutsche ◽  
Dimitrije Marković
Keyword(s):  
Phase Space ◽  
Sir Model ◽  
Reaction Model ◽  
Space Representation ◽  
Cumulative Number ◽  
Short Term ◽  
Before And After ◽  
The Status ◽  
Short And Long Term

The distinct ways the COVID-19 pandemic has been unfolding in different countries and regions suggest that local societal and governmental structures play an important role not only for the baseline infection rate, but also for short and long-term reactions to the outbreak. We propose to investigate the question of how societies as a whole, and governments in particular, modulate the dynamics of a novel epidemic using a generalization of the SIR model, the reactive SIR (short-term and long-term reaction) model. We posit that containment measures are equivalent to a feedback between the status of the outbreak and the reproduction factor. Short-term reaction to an outbreak corresponds in this framework to the reaction of governments and individuals to daily cases and fatalities. The reaction to the cumulative number of cases or deaths, and not to daily numbers, is captured in contrast by long-term reaction. We present the exact phase space solution of the controlled SIR model and use it to quantify containment policies for a large number of countries in terms of short and long-term control parameters. We find increased contributions of long-term control for countries and regions in which the outbreak was suppressed substantially together with a strong correlation between the strength of societal and governmental policies and the time needed to contain COVID-19 outbreaks. Furthermore, for numerous countries and regions we identified a predictive relation between the number of fatalities within a fixed period before and after the peak of daily fatality counts, which allows to gauge the cumulative medical load of COVID-19 outbreaks that should be expected after the peak. These results suggest that the proposed model is applicable not only for understanding the outbreak dynamics, but also for predicting future cases and fatalities once the effectiveness of outbreak suppression policies is established with sufficient certainty. Finally, we provide a web app (https://itp.uni-frankfurt.de/covid-19/) with tools for visualising the phase space representation of real-world COVID-19 data and for exporting the preprocessed data for further analysis.

scholarly journals Duodenal Dysbiosis and Relation to the Efficacy of Proton Pump Inhibitors in Functional Dyspepsia

2021 ◽  
Vol 22 (24) ◽  
pp. 13609
Author(s):  
Lucas Wauters ◽  
Raúl Y. Tito ◽  
Matthias Ceulemans ◽  
Maarten Lambaerts ◽  
Alison Accarie ◽  
...  
Keyword(s):  
Functional Dyspepsia ◽  
Proton Pump Inhibitors ◽  
Proton Pump ◽  
Potential Role ◽  
Short Term ◽  
Beneficial Effects ◽  
Rrna Sequencing ◽  
Before And After

Proton pump inhibitors (PPI) may improve symptoms in functional dyspepsia (FD) through duodenal eosinophil-reducing effects. However, the contribution of the microbiome to FD symptoms and its interaction with PPI remains elusive. Aseptic duodenal brushings and biopsies were performed before and after PPI intake (4 weeks Pantoprazole 40 mg daily, FD-starters and controls) or withdrawal (2 months, FD-stoppers) for 16S-rRNA sequencing. Between- and within-group changes in genera or diversity and associations with symptoms or duodenal factors were analyzed. In total, 30 controls, 28 FD-starters and 19 FD-stoppers were followed. Mucus-associated Porphyromonas was lower in FD-starters vs. controls and correlated with symptoms in FD and duodenal eosinophils in both groups, while Streptococcus correlated with eosinophils in controls. Although clinical and eosinophil-reducing effects of PPI therapy were unrelated to microbiota changes in FD-starters, increased Streptococcus was associated with duodenal PPI effects in controls and remained higher despite withdrawal of long-term PPI therapy in FD-stoppers. Thus, duodenal microbiome analysis demonstrated differential mucus-associated genera, with a potential role of Porphyromonas in FD pathophysiology. While beneficial effects of short-term PPI therapy were not associated with microbial changes in FD-starters, increased Streptococcus and its association with PPIeffects in controls suggest a role for duodenal dysbiosis after long-term PPI therapy.

scholarly journals Disentangling niche theory and beta diversity change

2021 ◽  
Author(s):  
William Godsoe ◽  
Peter J Bellingham ◽  
Elena Moltchanova
Keyword(s):  
Beta Diversity ◽  
Price Equation ◽  
Short Term ◽  
Before And After ◽  
Environmental Requirements ◽  
Habitat Specialists ◽  
Montane Tropical Forest ◽  
Ecological Drift ◽  
Over Time

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favours habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e. its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

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