Analysis of KATL Operation Simulated by TAAM

2015 ◽  
Vol 713-715 ◽  
pp. 1601-1604
Author(s):  
Xue Hua Zhang
Keyword(s):  
Baseline Model ◽  
Operating Condition ◽  
Flight Schedules ◽  
The Impact

This objective of this research is to use Jeppesen’s Total Airspace and Airport Modelersimulator of airport and airspace operations (TAAM). TAAM has the capability to create models of airspace and airports, which makes it easy to planning, analysis, and making a decision. TAAM can help researchers evaluating the impact of changes to infrastructure, operations and schedules, after mimicking the airspace or airport into model.The simulation of this paper is going to imitate the operation of KATL in two different layouts with three different flight schedules based on a valid baseline model. In this case, the study is based on VFR operating condition, and operating towards west.

scholarly journals A Quantitative Risk Assessment of Human Salmonellosis from Consumption of Walnuts in the United States

2018 ◽  
Vol 82 (1) ◽  
pp. 45-57 ◽  
Author(s):  
SOFIA M. SANTILLANA FARAKOS ◽  
RÉGIS POUILLOT ◽  
GORDON R. DAVIDSON ◽  
RHOMA JOHNSON ◽  
INSOOK SON ◽  
...  
Keyword(s):  
United States ◽  
Rare Event ◽  
The United States ◽  
Quantitative Risk Assessment ◽  
World Health ◽  
Baseline Model ◽  
Log Reduction ◽  
Human Salmonellosis ◽  
Health Organization ◽  
The Impact

ABSTRACT We assessed the risk of human salmonellosis from consumption of shelled walnuts in the United States and the impact of 0- to 5-log reduction treatments for Salmonella during processing. We established a baseline model with Salmonella contamination data from 2010 to 2013 surveys of walnuts from California operations to estimate baseline prevalence and levels of Salmonella during preshelling storage and typical walnut processing stages, considered U.S. consumption data, and applied an adapted dose-response model from the Food and Agriculture Organization and the World Health Organization to evaluate risk of illness per serving and per year. Our baseline model predicted 1 case of salmonellosis per 100 million servings (95% confidence interval [CI], 1 case per 3 million to 1 case per 2 billion servings) of walnuts untreated during processing and uncooked by consumers, resulting in an estimated 6 cases of salmonellosis per year (95% CI, <1 to 278 cases) in the United States. A minimum 3-log reduction treatment for Salmonella during processing of walnuts eaten alone or as an uncooked ingredient resulted in a mean risk of <1 case per year. We modeled the impact on risk per serving of three atypical situations in which the Salmonella levels were increased by 0.5 to 1.5 log CFU per unit pretreatment during processing at the float tank or during preshelling storage or posttreatment during partitioning into consumer packages. No change in risk was associated with the small increase in levels of Salmonella at the float tank, whereas an increase in risk was estimated for each of the other two atypical events. In a fourth scenario, we estimated the risk per serving associated with consumption of walnuts with Salmonella prevalence and levels from a 2014 to 2015 U.S. retail survey. Risk per serving estimates were two orders of magnitude larger than those of the baseline model without treatment. Further research is needed to determine whether this finding reflects variability in Salmonella contamination across the supply or a rare event affecting a portion of the supply.

Parametric Study on Ported Shroud Locations and Geometries for a Turbocharger Compressor

2019 ◽  
Author(s):  
Suheab Thamizullah ◽  
Abdul Nassar ◽  
Antonio Davis ◽  
Gaurav Giri ◽  
Leonid Moroz
Keyword(s):  
Centrifugal Compressor ◽  
Combustion Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Entire Study ◽  
Operating Condition ◽  
Baseline Design ◽  
Operating Range ◽  
Ported Shroud ◽  
The Impact

Abstract Turbochargers are commonly used in automotive engines to increase the internal combustion engine performance during off-design operating conditions. When used, the widest operating range for the turbocharger is desired, which is limited on the compressor side by the choke condition and the surge phenomenon. The ported shroud technology is used to extend the operable working range of the compressor, by permitting flow disturbances that block the blade passage to escape and stream back through the shroud cavity to the compressor inlet. The impact of this technology, on a speed-line, at near optimal operating condition, near choke operating condition and near surge operating condition is investigated. The ported shroud (PS) self-recirculating casing treatment is widely used to delay the onset of surge by enhancing the aerodynamic stability of the turbocharger compressor. While the ported shroud design delays surge, it usually comes with a small penalty in efficiency. This research involves designing a single-stage centrifugal compressor for the given specifications, considering the application of an automotive turbocharger. The ported shroud was then introduced in the centrifugal compressor. The performance characteristics were obtained, both at the design and at off-design conditions, both with and without the ported shroud. The performance was compared at various off-design operating speed lines. The entire study, from designing the compressor to optimizing the ported shroud configuration, was performed using the commercial AxSTREAM® software platform. Parametric studies were performed to study the effect of ported shroud axial location along the blade axial length on the operating range and performance. The baseline design, without the ported shroud (P0), and the final geometry with it for all PS inlet axial locations (P1 to P5) were analysed using a commercial CFD package and the results were compared with those from the streamline solver.

Operational safety of automated and human driving in mixed traffic environments: A perspective of car-following behavior

2021 ◽  
pp. 1748006X2110506
Author(s):  
Tao Li ◽  
Xu Han ◽  
Jiaqi Ma ◽  
Marilia Ramos ◽  
Changju Lee
Keyword(s):  
Traffic Safety ◽  
Risk Mitigation ◽  
Safety Evaluation ◽  
Mixed Traffic ◽  
Trajectory Data ◽  
Road Transportation ◽  
Baseline Model ◽  
Car Following ◽  
On The Road ◽  
The Impact

The advent of automated vehicles (AVs) will provide opportunities for safer, smoother, and smarter road transportation. During the transition from the current human-driven vehicle (HV) to a fully AV traffic environment, there will be a mixed traffic flow including both HVs and AVs. The impact of introducing AVs into existing traffic, however, has not yet been fully understood. In this paper, we advance this understanding by conducting mixed traffic safety evaluation from the perspective of car-following behavior using real-world AV operational data of mixed traffic. To understand how the AVs impact other vehicles on the road, we analyzed the operational behaviors of HV-following-HV, AV-following-HV, and HV-following-AV. A selected car-following model is calibrated, and results show that there are significant differences between the HV-following-HV and the other two groups, indicating safe AV behavior and changes in HV behavior (i.e. less aggressive, safer) after the introduction of AVs into the traffic. Additionally, to understand AV behavioral safety, we investigate behavior predictions (one of the most critical inputs for AVs to make car-following decisions) of AVs and their surrounding vehicles using a mature baseline model and a new Conditional Variational Autoencoder (CVAE) framework. The result shows potential risks of inaccurate predictions of the baseline model and the necessity to consider additional factors, such as vehicle interactions and driver behavior, into the prediction for risk mitigation. Arterial vehicle trajectory data from the Lyft Level 5 Dataset is applied to test the proposed methodological framework to understand the car-following safety risks of HVs and AVs in the mixed traffic stream.

scholarly journals Investigating Tourists’ Revisit Proxies: The Key Role of Destination Loyalty and Its Dimensions

2018 ◽  
Vol 58 (7) ◽  
pp. 1123-1145 ◽  
Author(s):  
Nikolaos Stylos ◽  
Victoria Bellou
Keyword(s):  
Place Attachment ◽  
Explanatory Power ◽  
Subjective Norms ◽  
Baseline Model ◽  
Destination Loyalty ◽  
Tourism Marketing ◽  
Main Components ◽  
The Impact ◽  
Intention To Revisit

Literature in tourism marketing has focused on understanding tourists’ revisit patterns, mostly through its proxies (i.e., destination loyalty, past visitation, intention to revisit). Interestingly, however, consensus has not been reached yet, regarding not only the distinctiveness of these proxies but also their interrelationships. This study hypothesizes the impact of past visitation, along with holistic image and subjective norms, on tourists’ intention to revisit directly, and via destination loyalty, expecting place attachment to serve as key moderator. Additionally, since research remains quite vague in terms of the destination loyalty components and their operationalization, this study tests other than the baseline model, a competing one, in which we replace destination loyalty construct with two of its main components, namely, destination commitment and intention to recommend. Evidence coming from 1,292 British tourists visiting Crete, Greece, verifies the distinctiveness of the three proxies and identifies the superior explanatory power of the competing model.

Dynamic Analysis of Planar Solid Oxide Fuel Cell Models With Different Assumptions of Temperature Layers

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Handa Xi ◽  
Jing Sun
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Model Performance ◽  
System Optimization ◽  
Solid Oxide ◽  
High Fidelity ◽  
Oxide Fuel ◽  
Baseline Model ◽  
Trade Off ◽  
The Impact

As solid oxide fuel cell (SOFC) technology is rapidly evolving, high-fidelity mathematical models based on physical principles have become essential tools for SOFC system design and analysis. While several SOFC models have been developed by different groups using different modeling assumptions, little analysis of the effects of these assumptions on model performance can be found in literature. Meanwhile, to support system optimization and control design activities, a trade-off often has to be made between high fidelity and low complexity. This trade-off can be influenced by the number of temperature layers assumed in the energy balance to represent the SOFC structure. In this paper, we investigate the impact of the temperature layer assumption on the performance of the dynamic planar SOFC model. Four models of co-flow planar SOFCs are derived using the finite volume discretization approach along with different assumptions in the number of temperature layers. The model with four temperature layers is used as the baseline model, and the other models aimed at reducing the complexity of the baseline model are developed and compared through simulations as well as linear analysis. We show that the model with as few as two temperature layers—the solid structure and air bulk flow—is able to capture the dynamics of SOFCs, while assuming only one temperature layer results in significantly large modeling error.

scholarly journals Effects of Most to Least Prompting Procedure on Teaching Exercise for Adults with Intellectual Disabilities

2018 ◽  
Vol 6 (9a) ◽  
pp. 1 ◽  
Author(s):  
Özgür Kurt ◽  
Selmin Çuhadar
Keyword(s):  
Intellectual Disabilities ◽  
Multiple Baseline ◽  
Single Subject ◽  
Baseline Model ◽  
Dynamic Stretching ◽  
Post Test ◽  
Adults With Intellectual Disabilities ◽  
Teachers And Parents ◽  
The Impact ◽  
Stretching Exercises

In this research, the effectiveness of the most to least prompting instruction method in teaching dynamic stretching exercises to adults with intellectual disabilities has been evaluated. At the same time, the impact of this instruction on flexibility and balance which are among physical fitness components has also been determined. A single subject multiple baseline model across behaviors with probe conditions was used. Participants in the study were four women, 34-37 years old. The single opportunity method was used while collecting the data of the study, and all sessions were completed at the end of a period of 16-week. The results obtained from the study indicated that the most to least prompting method was influential in all the participants' learning about dynamic stretching exercises. At the same time, result of the evaluation of the pre-test and post-test measures revealed increases in flexibility and balance of the participants in various ratios. The results of the study indicate that the most to least prompting method was an influential method in teaching dynamic stretching exercises to adults with intellectual disabilities, making these exercises maintenance and generalization them. The results of the interviews conducted with teachers and parents in the study showed that the views of teachers and parents towards the most to least prompting method were positive.

Optimal button arrangement of a percussion drill bit and its operating condition for improving drilling efficiency

2017 ◽  
Vol 232 (16) ◽  
pp. 2887-2898 ◽  
Author(s):  
Hoon Kang ◽  
Jin-Young Park ◽  
Jung-Woo Cho ◽  
Jin-Seok Jang ◽  
Kun-Woo Kim ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Rock Surface ◽  
Drill Bit ◽  
Operating Condition ◽  
Drilling Performance ◽  
Impact Area ◽  
Specific Operating Condition ◽  
The Impact

This paper proposes an optimal button arrangement of a percussion drill bit and its operating condition to improve drilling efficiency. A new evaluation method is introduced for the button arrangement that utilizes the superimposed impact area, blank area, and drilling deviation moment as the quantitative indices to evaluate the impact of buttons on the rock surface. To determine the optimal button arrangement and its operating conditions, a progressive metamodel-based design optimization was conducted using the new evaluation indices as the analysis response, and then the optimal solution was determined through iteration. Consequently, all the button evaluation indices were reduced significantly and the impact areas were distributed uniformly under a specific operating condition. Additionally, the drilling performances of the optimal button arrangement were investigated according to the operating conditions to obtain the maximum drilling performance in terms of the drilling machine operation.

Analysis and Comparison of Clean vs Inlet Distortion Flow Physics at Design Operating Condition Using Proper Orthogonal Decomposition

2015 ◽  
Author(s):  
Ronald A. Spencer ◽  
Steven E. Gorrell ◽  
Matthew R. Jones ◽  
Earl P. N. Duque
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Orthogonal Decomposition ◽  
Flow Distortion ◽  
Efficient Operation ◽  
Operating Condition ◽  
Shock Location ◽  
Stage Performance ◽  
Engineered Systems ◽  
Proper Orthogonal ◽  
The Impact

Assessing the impact of inlet flow distortion in turbomachinery is critical to the safe and efficient operation of many engineered systems. This paper introduces and validates the use of methods based on the Proper Orthogonal Decomposition (POD) to analyze clean and 1/rev static pressure distortion simulation results at design operating condition. The value of POD comes in its ability to efficiently extract both quantitative and qualitative information about dominant spatial flow structures as well as information about temporal fluctuations in flow properties. The analysis was used to quantify circumferential varying stage performance in terms of shock location and strength. Since the result of 1/rev total pressure distortion is circumferential varying stage performance, POD is a useful means to analyze and quantify such variation. Observation of the modes allowed qualitative identification of shockwaves as well as quantification of their location and range of motion. Modal coefficients revealed the location of the passage shock at a given angular location. Distortion amplification and attenuation between rotors was also identified.

scholarly journals Zračni promet i turizam Primorske Hrvatske

Geoadria ◽  
2011 ◽  
Vol 16 (2) ◽  
pp. 155
Author(s):  
Slaven Gašparović
Keyword(s):  
Low Cost ◽  
Air Transportation ◽  
General Aviation ◽  
Air Transport ◽  
Considerable Part ◽  
Flight Schedules ◽  
Littoral Region ◽  
Time Period ◽  
The Impact ◽  
Overnight Stays

The aim of this paper is to analyse and explain the impact of air transportation on the development of tourism in the Croatian littoral. The analysis was made by using the data collected from flight schedules and airport authorities. The data on frequency of lines and number of passengers were analysed in order to correlate the distribution of the number of passengers with the number of tourists during the year. In this case, the correlation between the number of passengers and the number of arrivals/number of overnight stays is observed. Data for the time period from 2008 till 2010 were analysed in more detail by dividing the passengers into four categories: full-service passengers, low-cost passengers, charter passengers and general aviation passengers. Major touristic markets are identified on the basis of the number of connections between European and Croatian littoral airports. The last part of the paper deals with the increasing impact of low-cost services on the development of tourism in the Croatian littoral region. This is due to the fact that low-cost carriers have accounted for a considerable part of air transport in the last few years.

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