Time Estimation
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Author(s):  
D. Groetsch ◽  
K. Voelkel ◽  
H. Pflaum ◽  
K. Stahl

AbstractMany applications of wet multi-plate clutches are within safety-critical areas since malfunction or failure of the clutch is often equivalent to “loss of drive”.The main criterion for the estimation of damage and endurance of wet multi-plate clutches is the temperature on the friction interface. Owing to the thin, rotating geometry of the plates, determination of relevant temperatures in operation mode is almost impossible. State of the art is that there is no general applicable model for real-time estimation of clutch temperatures during operation.This contribution presents a validated parametric real-time temperature model that is applicable to various use cases and operating conditions. The model enables the calculation of the actual clutch temperature during operation and the prediction of temperature for future shifting operations.The model is validated by comparing temperature measurements from a component test rig and from the KUPSIM thermal clutch design tool with the developed real-time temperature calculation. The validity of the model for serial parts from industry and automotive applications under various load cases (clutch mode, continuous slip, non-steady slip) is demonstrated. The deviation between measurement and calculation are typically very small (< 5 K). The temperature prediction allows a highly accurate (deviations typically < 5 K) conservative prediction of the thermal load for future shifting operations.The model can thus contribute to the increase of operational safety of wet multi-plate clutches while at the same time facilitating optimal component design by reducing thermal over-dimensioning of clutches.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
De Chen ◽  
Peter A. Hosner ◽  
Donna L. Dittmann ◽  
John P. O’Neill ◽  
Sharon M. Birks ◽  
...  

Abstract Background Divergence time estimation is fundamental to understanding many aspects of the evolution of organisms, such as character evolution, diversification, and biogeography. With the development of sequence technology, improved analytical methods, and knowledge of fossils for calibration, it is possible to obtain robust molecular dating results. However, while phylogenomic datasets show great promise in phylogenetic estimation, the best ways to leverage the large amounts of data for divergence time estimation has not been well explored. A potential solution is to focus on a subset of data for divergence time estimation, which can significantly reduce the computational burdens and avoid problems with data heterogeneity that may bias results. Results In this study, we obtained thousands of ultraconserved elements (UCEs) from 130 extant galliform taxa, including representatives of all genera, to determine the divergence times throughout galliform history. We tested the effects of different “gene shopping” schemes on divergence time estimation using a carefully, and previously validated, set of fossils. Our results found commonly used clock-like schemes may not be suitable for UCE dating (or other data types) where some loci have little information. We suggest use of partitioning (e.g., PartitionFinder) and selection of tree-like partitions may be good strategies to select a subset of data for divergence time estimation from UCEs. Our galliform time tree is largely consistent with other molecular clock studies of mitochondrial and nuclear loci. With our increased taxon sampling, a well-resolved topology, carefully vetted fossil calibrations, and suitable molecular dating methods, we obtained a high quality galliform time tree. Conclusions We provide a robust galliform backbone time tree that can be combined with more fossil records to further facilitate our understanding of the evolution of Galliformes and can be used as a resource for comparative and biogeographic studies in this group.


2021 ◽  
Author(s):  
Sebastian Hoehna ◽  
Sarah E Lower ◽  
Pablo Duchen ◽  
Ana Catalan

Fireflies (Coleoptera: Lampyridae) consist of over 2,000 described extant species. A well-resolved phylogeny of fireflies is important for the study of their bioluminescence, evolution, and conservation. We used a recently published anchored hybrid enrichment dataset (AHE; 436 loci for 88 Lampyridae species and 10 outgroup species) and state-of-the-art statistical methods (the fossilized birth-death-range process implemented in a Bayesian framework) to estimate a time-calibrated phylogeny of Lampyridae. Unfortunately, estimating calibrated phylogenies using AHE and the latest and most robust time-calibration strategies is not possible because of computational constraints. As a solution, we subset the full dataset and applied three different strategies: using the most complete loci, the most homogeneous loci, and the loci with the highest accuracy to infer the well established Photinus clade. The estimated topology using the three data subsets agreed on almost all major clades and only showed minor discordance with less supported nodes. The estimated divergence times overlapped for all nodes that are shared between the topologies. Thus, divergence time estimation is robust as long as the topology inference is robust and any well selected data subset suffices. Additionally, we observed an unexpected amount of gene tree discordance between the 436 AHE loci. Our assessment of model adequacy showed that standard phylogenetic substitution models are not adequate for any of the 436 AHE loci which is likely to bias phylogenetic inferences. We performed a simulation study to explore the impact of (a) incomplete lineage sorting, (b) uniformly distributed and systematic missing data, and (c) systematic bias in the position of highly variable and conserved sites. For our simulated data, we observed less gene tree variation and hence the empirically observed amount of gene tree discordance for the AHE dataset is unexpected.


2021 ◽  
Vol 3 (1) ◽  
pp. C21A03-1-C21A03-4
Author(s):  
Moumouni Djibo ◽  
◽  
Wendyam Boris Serge Ouedraogo ◽  
Ali Doumounia ◽  
Serge Sanou ◽  
...  

Several factors can attenuate radio signal between transmitting and receiving antenna. One can cite: vegetation, atmospheric gases, fog, water vapor, transmission instruments, rain, temperature, etc... The sources of attenuation differ according to the climate and the relief of each continent or even each country. In this work we aim to show that there is link between microwave signal attenuation and weather visibility in the presence of dust. Weather visibility is a very important factor for the safety of road, sea, rail and air transportation. In the presence of dust, the visibility is strongly reduced and there is also a strong attenuation of the microwave signal propagating between two antennas. By performing a linear regression on the attenuation-visibility scatter plot, we propose a method for real-time estimation of the visibility knowing the microwave signals attenuation. A correlation measurement between the visibility estimated by our method from the real attenuation data of the mobile phone operator Telecel Faso SA (Burkina Faso) and the visibility measured by the National Meteorological Agency of Burkina Faso (ANAM) gave a correlation coefficient of 0.86.


2021 ◽  
Author(s):  
◽  
Julie Anne Séguin

<p>Activation and attention have opposite effects on time perception. Emotion can both increase physiological activation (which leads to overestimation of time) and attract attention (which leads to underestimation of time). Although the effect of emotion on time perception has received a growing amount of attention, the use of different time estimation tasks and stimuli makes it difficult to compare findings across studies. The effect of emotion on the temporal perception of complex stimuli (e.g. scenes) is particularly under-researched. This thesis presents a systematic assessment of the effect of two key emotional dimensions, arousal and valence, on time perception for visual stimuli. Studies were designed to control for factors that may modulate emotion effects, such as image repetition and carry over from one emotion to another. The stimuli were complex images standardized for arousal (high or low) and valence (positive or negative) as well as neutral images. The first study compared three time estimation tasks to determine which were sensitive to emotion effects. The selected task, temporal bisection, was used to test time perception in three duration ranges: short (400 to 1600ms), middle (1000 to 4000ms), and long (2000 to 6000ms). Results of bisection point analyses revealed that the duration of attention-capturing stimuli (e.g. high arousal or negative images) was underestimated compared to that of other stimuli (e.g. low arousal or neutral images). These findings are at odds with activational effects of emotion (overestimation of emotional stimuli), which are typically found in studies of time perception for facial expression. Better temporal sensitivity in the long range than in short and middle ranges suggests that participants used different timing strategies to perform the bisection task at longer stimulus durations. To test the effect of emotion on time perception using a discrete rather than dimensional classification of emotion, experiments were replicated using emotional facial expressions as stimuli. Time estimates in the short and middle ranges did not show attentional effects, but pointed to activational effects of emotion. Facial expression had no impact on time perception in the long duration range. Taken together, these experiments show that the effect of emotion on time perception varies according to both duration and stimulus type. Emotional facial expressions have short lived activational effects whereby the duration of arousing stimuli is overestimated, whereas complex emotional scenes have protracted attentional effects through which the duration of attention-capturing stimuli is underestimated.</p>


2021 ◽  
Author(s):  
◽  
Julie Anne Séguin

<p>Activation and attention have opposite effects on time perception. Emotion can both increase physiological activation (which leads to overestimation of time) and attract attention (which leads to underestimation of time). Although the effect of emotion on time perception has received a growing amount of attention, the use of different time estimation tasks and stimuli makes it difficult to compare findings across studies. The effect of emotion on the temporal perception of complex stimuli (e.g. scenes) is particularly under-researched. This thesis presents a systematic assessment of the effect of two key emotional dimensions, arousal and valence, on time perception for visual stimuli. Studies were designed to control for factors that may modulate emotion effects, such as image repetition and carry over from one emotion to another. The stimuli were complex images standardized for arousal (high or low) and valence (positive or negative) as well as neutral images. The first study compared three time estimation tasks to determine which were sensitive to emotion effects. The selected task, temporal bisection, was used to test time perception in three duration ranges: short (400 to 1600ms), middle (1000 to 4000ms), and long (2000 to 6000ms). Results of bisection point analyses revealed that the duration of attention-capturing stimuli (e.g. high arousal or negative images) was underestimated compared to that of other stimuli (e.g. low arousal or neutral images). These findings are at odds with activational effects of emotion (overestimation of emotional stimuli), which are typically found in studies of time perception for facial expression. Better temporal sensitivity in the long range than in short and middle ranges suggests that participants used different timing strategies to perform the bisection task at longer stimulus durations. To test the effect of emotion on time perception using a discrete rather than dimensional classification of emotion, experiments were replicated using emotional facial expressions as stimuli. Time estimates in the short and middle ranges did not show attentional effects, but pointed to activational effects of emotion. Facial expression had no impact on time perception in the long duration range. Taken together, these experiments show that the effect of emotion on time perception varies according to both duration and stimulus type. Emotional facial expressions have short lived activational effects whereby the duration of arousing stimuli is overestimated, whereas complex emotional scenes have protracted attentional effects through which the duration of attention-capturing stimuli is underestimated.</p>


Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2754
Author(s):  
Saul Jimenez ◽  
Ernesto Vázquez ◽  
Francisco Gonzalez-Longatt

This paper proposed a methodology of adaptive instantaneous overcurrent protection (AIOCP) setting that ensures that the protection coverage remains unchanged regardless of the operating condition of the electrical network. The methodology calculates the protection setting parameters based on the real-time estimation of the Thevenin equivalent circuit (TEC). The estimation algorithm uses the positive-sequence voltage and current values and a system of non-linear equations, which is solved iteratively by the Gauss–Newton method. The proposed methodology calculates the IOCP settings in real time by using the real-time estimation of the TEC; therefore, any change in the electric network conditions is represented in the TEC, and the calculated setting keeps the desired protection coverage constant. Simulation results demonstrate that the proposed AIOCP can keep constant the protection coverage overcoming the classical problems of classical IOCP: sub-allocation and over-coverage.


2021 ◽  
Author(s):  
Cecilia Polizzi ◽  
Serena Falcioni ◽  
Alberto Mannucci ◽  
Gualtiero Mori ◽  
Arianna Nardi ◽  
...  

Abstract Wastewater treatment plants (WWTP) are required to meet increasingly stringent effluent quality standards as well as to improve process sustainability in terms of energy efficiency, in line with the call for a paradigm shift towards the more sustainable concept of wastewater resource recorvery facility (WRRF). In this context, optimised Instrumentation, Control and Automation (ICA) systems as well as process and plant-wide modelling have become key tools for optimising economic and environmental costs. The present work reports on the succesfull integration of an innovative on-line continuous titrimeter and plant-wide modelling as a support tool for the optimisation of the nitritification unit in a large-scale industrial WWTP. The information gathered from the on-line titrimeter allowed for real-time estimation of the Ammonia Oxidation Rate of the activated sludge and, ultimately, of the nitrification residual capacity of the plant. Results on the titrimeter long-term operation and historical data modelling supported plant managing decisions, such as lowering the DO set-point of the oxidation unit, straightforwardly resulting in energy saving.


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