Study on Temperature Distribution Characteristic of Asphalt Mixtures of Bridge Deck

2010 ◽  
Vol 163-167 ◽  
pp. 1829-1832
Author(s):  
Qing Long You ◽  
Nan Xiang Zheng ◽  
Gang Lei Shi
Keyword(s):  
Temperature Distribution ◽  
Temperature Profile ◽  
Bridge Deck ◽  
Prediction Models ◽  
Asphalt Pavement ◽  
Highway Bridges ◽  
Temperature Prediction ◽  
Road Pavement ◽  
Load Carrying ◽  
The Difference

Flexible pavements comprise a majority part of highways in china. Many highway bridges are constructed in these highways. These primary highway bridges are subjected to the same heavy loading as the conventional asphalt pavement, but caused much more significant damage than the conventional asphalt pavement. As hot-mix asphalt (HMA) is a visco-elastic material and the all around environment is different between road pavement and bridge deck, the structural or load-carrying capacity of road pavement and bridge deck is different. Thus, to accurately determine in situ strength characteristics of flexible pavement, it is necessary to predict the temperature distribution within the HMA layers and find the difference between road pavement and bridge deck. The majority of previously published research concentrated on pavement temperature prediction. To confirm the bridge deck temperature profile, observing the temperature at bridge deck and road pavement for two months. Compared with the temperature profile of bridge deck and road pavement, find the difference between them. Then some daily temperature prediction models are analyzed and develop a modified double-sine model to simulate the surface temperature variation of bridge deck.

Study on Temperature Prediction Model of Asphalt Concrete Pavement

2011 ◽  
Vol 243-249 ◽  
pp. 506-509
Author(s):  
Yuan Xun Zheng ◽  
Ying Chun Cai ◽  
Ya Min Zhang
Keyword(s):  
Asphalt Concrete ◽  
Prediction Models ◽  
Asphalt Pavement ◽  
Temperature Data ◽  
Measured Temperature ◽  
Temperature Prediction ◽  
Distribution Laws ◽  
Pavement Temperature ◽  
Asphalt Concrete Pavement ◽  
Excellent Accuracy

This study presents a kind of new model correlates air and pavement temperatures in bituminous pavement. Based on abundant measured temperature data in Henan Province, China, distribution laws in asphalt conctete pavement temperature is studied detailed and the dependency between air and pavement temperature is discussed by the method of regression analysis and the prediction models of asphalt pavement temperature are established. Comparisons between measured and predicted asphalt pavement temperatures indicate that the models are equipped with comprehensive applicability and excellent accuracy.

scholarly journals Ripeness Prediction of Postharvest Kiwifruit Using a MOS E-Nose Combined with Chemometrics

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 419 ◽  
Author(s):  
Dongdong Du ◽  
Jun Wang ◽  
Bo Wang ◽  
Luyi Zhu ◽  
Xuezhen Hong
Keyword(s):  
Prediction Models ◽  
Extraction Methods ◽  
Oxide Semiconductor ◽  
Soluble Solids ◽  
Support Vector ◽  
Least Squares Regression ◽  
Accuracy Rate ◽  
Linear Discriminant ◽  
The Difference ◽  
Ripe Stage

Postharvest kiwifruit continues to ripen for a period until it reaches the optimal “eating ripe” stage. Without damaging the fruit, it is very difficult to identify the ripeness of postharvest kiwifruit by conventional means. In this study, an electronic nose (E-nose) with 10 metal oxide semiconductor (MOS) gas sensors was used to predict the ripeness of postharvest kiwifruit. Three different feature extraction methods (the max/min values, the difference values and the 70th s values) were employed to discriminate kiwifruit at different ripening times by linear discriminant analysis (LDA), and results showed that the 70th s values method had the best performance in discriminating kiwifruit at different ripening stages, obtaining a 100% original accuracy rate and a 99.4% cross-validation accuracy rate. Partial least squares regression (PLSR), support vector machine (SVM) and random forest (RF) were employed to build prediction models for overall ripeness, soluble solids content (SSC) and firmness. The regression results showed that the RF algorithm had the best performance in predicting the ripeness indexes of postharvest kiwifruit compared with PLSR and SVM, which illustrated that the E-nose data had high correlations with overall ripeness (training: R2 = 0.9928; testing: R2 = 0.9928), SSC (training: R2 = 0.9749; testing: R2 = 0.9143) and firmness (training: R2 = 0.9814; testing: R2 = 0.9290). This study demonstrated that E-nose could be a comprehensive approach to predict the ripeness of postharvest kiwifruit through aroma volatiles.

scholarly journals Seismic Damage Accumulation in Highway Bridges in Earthquake-Prone Regions

2015 ◽  
Vol 31 (1) ◽  
pp. 115-135 ◽  
Author(s):  
Jayadipta Ghosh ◽  
Jamie E. Padgett ◽  
Mauricio Sánchez-Silva
Keyword(s):  
Service Life ◽  
Damage Accumulation ◽  
Main Shock ◽  
Prediction Models ◽  
Time Window ◽  
Damage Index ◽  
Active Regions ◽  
Highway Bridges ◽  
Main Shocks ◽  
Aftershock Sequences

Civil infrastructures, such as highway bridges, located in seismically active regions are often subjected to multiple earthquakes, including multiple main shocks during their service life or main shock–aftershock sequences. Repeated seismic events result in reduced structural capacity and may lead to bridge collapse, causing disruption in the normal functioning of transportation networks. This study proposes a framework to predict damage accumulation in structures subjected to multiple shock scenarios after developing damage index prediction models and accounting for the probabilistic nature of the hazard. The versatility of the proposed framework is demonstrated on a case-study highway bridge located in California for two distinct hazard scenarios: (1) multiple main shocks during the service life and (2) multiple aftershock earthquake occurrences following a single main shock. Results reveal that in both cases there is a significant increase in damage index exceedance probabilities due to repeated shocks within the time window of interest.

scholarly journals A Method for Determining the Main Requirements of Outlet Gas Temperature Profile of Marine Gas Turbine Combustors

1982 ◽  
Author(s):  
Tang Chian-ti
Keyword(s):  
Temperature Distribution ◽  
Temperature Profile ◽  
Gas Turbine ◽  
Guide Vane ◽  
Safety Margin ◽  
Gas Temperature ◽  
Distribution Factor ◽  
Radial Temperature ◽  
Blade Height ◽  
Blade Cooling

Taking account of the marine gas turbine operation features, the author has chosen the hot corrosion peak temperature of materials as the guide vane material limiting temperature while evaluating the overall temperature distribution factor. Along with the blade cooling effectiveness a safety margin factor has been introduced during its evaluation. The gas temperature distribution along blade height is assumed to satisfy the condition that approximately equal safety factor in respect of strength prevails along blade height. Once the gas radial temperature profile becomes known, the radial temperature distribution factor can be readily determined.

The impact of London on a low-level jet

2021 ◽  
Author(s):  
Aristofanis Tsiringakis ◽  
Natalie Theeuwes ◽  
Janet Barlow ◽  
Gert-Jan Steeneveld
Keyword(s):  
Urban Area ◽  
Prediction Models ◽  
Weather Prediction ◽  
Vertical Mixing ◽  
Forecasting Model ◽  
Low Level ◽  
Low Level Jet ◽  
The Difference ◽  
The Impact ◽  
Numerical Weather Prediction Models

<p>The low-level jet (LLJ) is an important phenomenon that can affect (and is affected by) the turbulence in the nocturnal urban boundary layer (UBL). We investigate the interaction of a regional LLJ with the UBL during a 2-day period over London. Observations from two Doppler Lidars and two numerical weather prediction models (Weather Research & Forecasting model and UKV Met Office Unified Model) are used to compared the LLJ characteristics (height, speed and fall-off) between a urban (London) and a rural (Chilbolton) site. We find that LLJs are elevated (70m) over London, due to the deeper UBL, an effect of the increased vertical mixing over the urban area and the difference in the topography between the two sites. Wind speed and fall-off are slightly reduced with respect to the rural LLJ. The effects of the urban area and the surrounding topography on the LLJ characteristics over London are isolated through idealized sensitivity experiments. We find that topography strongly affects the LLJ characteristics (height, falloff, and speed), but there is still a substantial urban influence.</p>

Strengthening Paudèze bridges decks using UHPFRC struts

2019 ◽  
Author(s):  
Philippe Menétrey ◽  
Lionel Moreillon ◽  
Maléna Bastien-Masse
Keyword(s):  
High Performance ◽  
Bridge Deck ◽  
Experimental Tests ◽  
Highway Bridges ◽  
Fiber Reinforced Concrete ◽  
Bending Moments ◽  
Box Girder ◽  
High Performance Fiber ◽  
Over 40 Years ◽  
Deck Slab

<p>Paudèze bridges are two 400‐m long parallel highway bridges located in Switzerland and opened to traffic in 1974. After over 40 years of service life, both bridges must be completely rehabilitated and strengthened while constantly maintaining 2 traffic lanes in both directions.</p><p>The bridge deck slab was strengthened using UHPFRC (Ultra‐High Performance Fiber Reinforced Concrete) struts. These inclined struts connect the end of the deck slab cantilever and the box girder web, forming a Warren truss. They thus reduce the bending moments in the deck slab and the existing steel reinforcement could be kept.</p><p>The joint between the prefabricated UHPFRC struts and the existing concrete web is done through a cast in‐ place UHPFRC beam, without any mechanical connection. Forces go through the joint and into the web by a combination of friction and compression forces.</p><p>Various experimental tests and numerical simulations confirmed the feasibility of this solution. In particular, the UHPFRC‐concrete web connection, the UHPFRC‐UHPFRC connection and the global behavior of the strut were tested and modelled.</p><p>The strengthening of the bridges decks took place between 2017 and 2019. The developed solution, using UHPFRC struts, was shown to be very effective to strengthen the deck and creates a rhythm in the structure.</p>

Effect of Minimum Quantity Lubrication to Prediction of Cutting Temperature Distribution in Turning Material AISI-1045

2020 ◽  
Vol 902 ◽  
pp. 97-102
Author(s):  
Tran Trong Quyet ◽  
Pham Tuan Nghia ◽  
Nguyen Thanh Toan ◽  
Tran Duc Trong ◽  
Luong Hong Sam ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Shear Zone ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Chip Thickness ◽  
Minimum Quantity Lubrication ◽  
Minimum Quantity ◽  
The Difference ◽  
Secondary Shear Zone ◽  
Cutting Model

This paper presents a prediction of cutting temperature in turning process, using a continuous cutting model of Johnson-Cook (J-C). An method to predict the temperature distribution in orthogonal cutting is based on the constituent model of various material and the mechanics of their cutting process. In this method, the average temperature at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thicknes. The J-C model constants were taken from Hopkinson pressure bar tests. Cutting conditions, cutting forces and chip thickness were used to predict shear stress. Experimental cutting heat results with the same cutting parameters using the minimum lubrication method (MQL) were recorded through the Testo-871 thermal camera. The thermal distribution results between the two methods has a difference in value, as well as distribution. From the difference, we have analyzed some of the causes, finding the effect of the minimum quantity lubrication parameters on the difference.

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