Temperature Control Planning Tool for Multi-Lift Resurfacing of Airport Pavements

2019 ◽  
Vol 2673 (7) ◽  
pp. 380-389 ◽  
Author(s):  
Longjia Chu ◽  
Baihe Zhu ◽  
T. F. Fwa
Keyword(s):  
Simulation Model ◽  
Temperature Control ◽  
Time Variation ◽  
Time Window ◽  
Asphalt Mixture ◽  
Time Lapse ◽  
Planning Tool ◽  
Time Duration ◽  
Deformation And Failure ◽  
Temperature Time

Overnight repairs and resurfacing of runway or taxiway pavements are common in busy airports. The time window available for such repair and resurfacing works is often limited. A common problem encountered is to ensure that the newly compacted asphalt mixture has cooled down sufficiently before receiving aircraft loadings, so as to avoid premature deformation and failure of the asphalt mixture. In this regard, a simulation model that provides a prediction of the temperature–time variation trend of each compacted pavement lift in a multi-lift asphalt course laying would be a valuable planning tool for temperature control. Information on the temperature cooling trend of an asphalt layer helps to estimate the time duration available for effective compaction during laying, as well as the time lapse needed before the pavement is sufficiently stable to receive traffic. A finite element simulation model is presented in this study to predict the temperature–time variation trends of successive asphalt lifts in a multi-lift asphalt mixture laying operation. The numerical model was developed based on the theory of thermodynamics taking into account the heat transfer effects of solar radiation, convection, and conduction. The model was calibrated and validated using data from a field trial involving a two-lift and a three-lift laying of asphalt mixtures. Illustrative examples are presented to demonstrate the applications of the simulation model as a temperature control planning tool for repair and resurfacing operations of airport pavements.

scholarly journals Hippocampal neurons with stable excitatory connectivity become part of neuronal representations

PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000928 ◽  
Author(s):  
Tim P. Castello-Waldow ◽  
Ghabiba Weston ◽  
Alessandro F. Ulivi ◽  
Alireza Chenani ◽  
Yonatan Loewenstein ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Pyramidal Neurons ◽  
Time Window ◽  
Structural Connectivity ◽  
Time Lapse ◽  
Early Gene ◽  
Synaptic Connectivity ◽  
Time Duration ◽  
Hippocampal Ca1 ◽  
Cornu Ammonis

Experiences are represented in the brain by patterns of neuronal activity. Ensembles of neurons representing experience undergo activity-dependent plasticity and are important for learning and recall. They are thus considered cellular engrams of memory. Yet, the cellular events that bias neurons to become part of a neuronal representation are largely unknown. In rodents, turnover of structural connectivity has been proposed to underlie the turnover of neuronal representations and also to be a cellular mechanism defining the time duration for which memories are stored in the hippocampus. If these hypotheses are true, structural dynamics of connectivity should be involved in the formation of neuronal representations and concurrently important for learning and recall. To tackle these questions, we used deep-brain 2-photon (2P) time-lapse imaging in transgenic mice in which neurons expressing the Immediate Early Gene (IEG) Arc (activity-regulated cytoskeleton-associated protein) could be permanently labeled during a specific time window. This enabled us to investigate the dynamics of excitatory synaptic connectivity—using dendritic spines as proxies—of hippocampal CA1 (cornu ammonis 1) pyramidal neurons (PNs) becoming part of neuronal representations exploiting Arc as an indicator of being part of neuronal representations. We discovered that neurons that will prospectively express Arc have slower turnover of synaptic connectivity, thus suggesting that synaptic stability prior to experience can bias neurons to become part of representations or possibly engrams. We also found a negative correlation between stability of structural synaptic connectivity and the ability to recall features of a hippocampal-dependent memory, which suggests that faster structural turnover in hippocampal CA1 might be functional for memory.

scholarly journals Guidelines to Calibrate a Multi-Residential Building Simulation Model Addressing Overheating Evaluation and Residents’ Influence

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 242
Author(s):  
Christoph Schünemann ◽  
David Schiela ◽  
Regine Ortlepp
Keyword(s):  
Simulation Model ◽  
Time Window ◽  
Residential Building ◽  
Simulation Models ◽  
Building Simulation ◽  
Night Time ◽  
Building Performance Simulation ◽  
Starting Point ◽  
3D Simulation Model ◽  
Building Physics

Can building performance simulation reproduce measured summertime indoor conditions of a multi-residential building in good conformity? This question is answered by calibrating simulated to monitored room temperatures of several rooms of a multi-residential building for an entire summer in two process steps. First, we did a calibration for several days without the residents being present to validate the building physics of the 3D simulation model. Second, the simulations were calibrated for the entire summer period, including the residents’ impact on evolving room temperature and overheating. As a result, a high degree of conformity between simulation and measurement could be achieved for all monitored rooms. The credibility of our results was secured by a detailed sensitivity analysis under varying meteorological conditions, shading situations, and window ventilation or room use in the simulation model. For top floor dwellings, a high overheating intensity was evoked by a combination of insufficient use of night-time window ventilation and non-heat-adapted residential behavior in combination with high solar gains and low heat storage capacities. Finally, the overall findings were merged into a process guideline to describe how a step-by-step calibration of residential building simulation models can be done. This guideline is intended to be a starting point for future discussions about the validity of the simplified boundary conditions which are often used in present-day standard overheating assessment.

Heating Performance Research in the Running-In Process of Wet Friction Clutch

2014 ◽  
Vol 614 ◽  
pp. 12-15
Author(s):  
Yu Fei Liu ◽  
Xiu Chao Bai ◽  
Xin Li ◽  
Yong Liang Lei
Keyword(s):  
Simulation Model ◽  
Temperature Control ◽  
Temperature Rise ◽  
Analysis Model ◽  
Heating Performance ◽  
Wet Friction ◽  
Friction Clutch ◽  
Simulation Results ◽  
Model Of Friction ◽  
Performance Research

The heating in the running-in process of wet friction clutch is the key to research in this kind of products. In this paper, based on the shifting clutch composed of metal and paper-based friction liner, using MATLAB/SIMULINK software, the simulation model of friction clutch and the analysis model of conducting heat were established. Thus, the corresponding relationships were obtained, which were the total friction power and clutch temperature variation with the time during the running-in process. According to the simulation results, the main influencing factors on temperature control of wet friction clutch were analyzed during running-in process, and the results could provide reference for reasonable temperature rise control for the clutch.

scholarly journals The Margin for Error When Releasing the Asymmetric Bars for Dismounts

2005 ◽  
Vol 21 (3) ◽  
pp. 223-235 ◽  
Author(s):  
Michael J. Hiley ◽  
Maurice R. Yeadon
Keyword(s):  
Simulation Model ◽  
Rotation Angle ◽  
Time Window ◽  
Model Parameters ◽  
Mass Center ◽  
Close Match ◽  
Traditional Technique ◽  
Margin For Error ◽  
Female Gymnasts ◽  
Actual Point

It has previously been shown that male gymnasts using the “scooped” giant circling technique were able to flatten the path followed by their mass center, resulting in a larger margin for error when releasing the high bar (Hiley & Yeadon, 2003a). The circling technique prior to performing double layout somersault dismounts from the asymmetric bars in women's artistic gymnastics appears to be similar to the “traditional” technique used by some male gymnasts on the high bar. It was speculated that as a result the female gymnasts would have margins for error similar to those of male gymnasts who use the traditional technique. However, it is unclear how the technique of the female gymnasts is affected by the need to avoid the lower bar. A 4-segment planar simulation model of the gymnast and upper bar was used to determine the margins for error when releasing the bar for 9 double layout somersault dismounts at the Sydney 2000 Olympics. The elastic properties of the gymnast and bar were modeled using damped linear springs. Model parameters, primarily the inertia and spring parameters, were optimized to obtain a close match between simulated and actual performances in terms of rotation angle (1.2°), bar displacement (0.011 m), and release velocities (<1%). Each matching simulation was used to determine the time window around the actual point of release for which the model had appropriate release parameters to complete the dismount successfully. The margins for error of the 9 female gymnasts (release window 43–102 ms) were comparable to those of the 3 male gymnasts using the traditional technique (release window 79–84 ms).

scholarly journals Long-term in vivo time-lapse imaging of synapse development and plasticity in the cerebellum

2014 ◽  
Vol 111 (1) ◽  
pp. 208-216 ◽  
Author(s):  
Naoko Nishiyama ◽  
Jeremy Colonna ◽  
Elise Shen ◽  
Jennifer Carrillo ◽  
Hiroshi Nishiyama
Keyword(s):  
In Vivo Imaging ◽  
Time Window ◽  
Time Lapse ◽  
Mammalian Brain ◽  
Cerebellar Neurons ◽  
Brain Functions ◽  
Time Lapse Imaging ◽  
Synaptic Circuitry

Synapses are continuously formed and eliminated throughout life in the mammalian brain, and emerging evidence suggests that this structural plasticity underlies experience-dependent changes of brain functions such as learning and long-term memory formation. However, it is generally difficult to understand how the rewiring of synaptic circuitry observed in vivo eventually relates to changes in animal's behavior. This is because afferent/efferent connections and local synaptic circuitries are very complicated in most brain regions, hence it is largely unclear how sensorimotor information is conveyed, integrated, and processed through a brain region that is imaged. The cerebellar cortex provides a particularly useful model to challenge this problem because of its simple and well-defined synaptic circuitry. However, owing to the technical difficulty of chronic in vivo imaging in the cerebellum, it remains unclear how cerebellar neurons dynamically change their structures over a long period of time. Here, we showed that the commonly used method for neocortical in vivo imaging was not ideal for long-term imaging of cerebellar neurons, but simple optimization of the procedure significantly improved the success rate and the maximum time window of chronic imaging. The optimized method can be used in both neonatal and adult mice and allows time-lapse imaging of cerebellar neurons for more than 5 mo in ∼80% of animals. This method allows vital observation of dynamic cellular processes such as developmental refinement of synaptic circuitry as well as long-term changes of neuronal structures in adult cerebellum under longitudinal behavioral manipulations.

scholarly journals Estimation of depth-resolved profiles of soil thermal diffusivity from temperature time series and uncertainty quantification

2021 ◽  
Author(s):  
Carlotta Brunetti ◽  
John Lamb ◽  
Stijn Wielandt ◽  
Sebastian Uhlemann ◽  
Ian Shirley ◽  
...  
Keyword(s):  
Time Series ◽  
Thermal Diffusivity ◽  
Physical Properties ◽  
Environmental Conditions ◽  
Temperature Sensor ◽  
Time Window ◽  
Temperature Time Series ◽  
Soil Thermal Diffusivity ◽  
Temperature Time ◽  
Over Time

Abstract. Improving the quantification of soil thermal and physical properties is key to achieving a better understanding and prediction of soil hydro-biogeochemical processes and their responses to changes in atmospheric forcing. Obtaining such information at numerous locations and/or over time with conventional soil sampling is challenging. The increasing availability of low-cost, vertically resolved temperature sensor arrays offers promise for improving the estimation of soil thermal properties from temperature time series, and the possible indirect estimation of physical properties. Still, the reliability and limitations of such an approach needs to be assessed. In the present study, we develop a parameter estimation approach based on a combination of thermal modeling, sliding time-windows, Bayesian inference, and Markov chain Monte Carlo simulation to estimate thermal diffusivity and its uncertainty over time, at numerous locations and at an unprecedented vertical spatial resolution (i.e., down to 5 to 10 cm vertical resolution) from soil temperature time series. We provide the necessary framework to assess under which environmental conditions (soil temperature gradient, fluctuations, and trend), temperature sensor characteristics (bias and level of noise) and deployment geometries (sensor number and position) soil thermal diffusivity can be reliably inferred. We validate the method with synthetic experiments and field studies. The synthetic experiments show that in the presence of median diurnal fluctuations ≥ 1.5 °C at 5 cm below the ground surface, temperature gradients > 2 °C m−1, and a sliding time-window of at least 4 days, the proposed method provides reliable depth-resolved thermal diffusivity estimates with percentage errors ≤ 10 % and posterior relative standard deviations ≤ 5 % up to 1 m depth. Reliable thermal diffusivity under such environmental conditions also requires temperature sensors spaced precisely (with few-millimeter accuracy), with a level of noise ≤ 0.02 °C, and with a bias defined by a standard deviation ≤ 0.01 °C. Finally, the application of the developed approach to field data indicates significant repeatability in results and similarity with independent measurements, as well as promise in using a sliding time-window to estimate temporal changes in soil thermal diffusivity, as needed to potentially capture changes in carbon or water content.

scholarly journals Effect of Controlled Temperature-Time Variation during the Chilled Storage of Beef on Tenderness Characteristics

2018 ◽  
Vol 2 (2) ◽  
pp. 84-84
Author(s):  
A. K. Kilgannon ◽  
B. Holman ◽  
A. J. Mawson ◽  
M. Campbell ◽  
D. Collins ◽  
...  
Keyword(s):  
Time Variation ◽  
Chilled Storage ◽  
Temperature Time

scholarly journals Fast detection technique for voltage unbalance in three-phase power system

2021 ◽  
Vol 12 (4) ◽  
pp. 2230
Author(s):  
Ibrahim I. Al-Naimi ◽  
Jasim A. Ghaeb ◽  
Mohammed J. Baniyounis ◽  
Mustafa Al-Khawaldeh
Keyword(s):  
Power Systems ◽  
Power System ◽  
Simulation Model ◽  
Cycle Time ◽  
Detection Technique ◽  
Detection Methods ◽  
Time Duration ◽  
Voltage Unbalance ◽  
Fast Detection ◽  
Three Phase

In this paper, the problem of voltage unbalance in the three-phase power systems is examined. A fast detection technique (FDT) is proposed to detect the voltage unbalance precisely and speedily. The well-known detection methods require more than one cycle time to detect the unbalanced voltages, whereas the proposed technique detects the unbalanced situations speedily in a discrete manner. Reducing the time duration required to detect the unbalanced voltages will enhance the dynamic response of the control system used to balance these voltages. The FDT acquires the instantaneous values of the three load voltages, calculates the sum and the space vector for these voltages at each sample, and utilizes these parameters to detect the voltage unbalance accurately within a quarter of the cycle time. A proof-of-concept simulation model for a real power system has been built. The parameters of the aqaba-qatrana-south amman (AQSA) Jordanian power system are considered in the simulation model. Also, several test cases have been conducted to test and validate the capabilities of the proposed technique.

Sign in / Sign up

Export Citation Format

Share Document