Air carriers shall not readily relinquish their held flight slots. In cases where the historical flight slot pool cannot be easily altered, a pressing need arises for an allocation method that can ...efficiently utilize the incremental resources of these time slots. This paper presents an integer planning model to address the efficient allocation of incremental airport time slot resources. The model considers the capacity of key resource nodes and flight waveforms as constraints to maximize the total incremental slots. Moreover, it considers the adaptation of strategic and tactical optimization. After conducting a case study using Beijing Capital International Airport for verification, the proposed model effectively reduces potential operational delays by 66.27% while adding 366 to 397-time slots. Notably, the model demonstrates remarkable delay reduction capabilities and can serve as a valuable decision-support tool for the incremental allocation of time slots.
In view of the common U-shaped apron structure of large- and medium-sized airports at home and abroad, this study considered the optimization design and performance evaluation of the U-shaped apron ...operation procedure. First, by analyzing the physical structure characteristics and traffic operation characteristics of the U-shaped area, exclusive, partition-shared, and global-shared operation procedures of the U-shaped area were designed, and differentiated apron-operation rules and traffic models were constructed for different types of operation procedures. Then, from the perspectives of safety, efficiency, and environmental protection, a multi-dimensional evaluation index system of U-shaped area operation performance is established, and a classification measurement and comprehensive evaluation method based on critique is proposed. Finally, a traffic simulation model was established based on airport network topology modeling. We used Monte Carlo methods for the simulation in Python 3.6, and the experimental results show that, in the scenario of high-density traffic operation, compared with exclusive and partition-shared procedures, the implementation effect of the global shared procedure is very significant, and the apron operation capacity increased by 14.8% and 5.0%, respectively. The probability of aircraft conflict decreased by 32.2% and 11.8%, respectively, and the time of single conflict relief decreased by 16.1 s and 10.6 s, respectively. The average resource utilization in each U-shaped area increased by 66% and 25%, respectively, while the average daily carbon emissions of a single aircraft were reduced by 16.7 kg and 11.0 kg and the average daily fuel consumption of a single aircraft were reduced by 3.6 kg and 2.4 kg, respectively. The proposed method is scientific and effective and can provide theoretical and methodological support for optimizing the configuration of the scene operation mode of complex airports and for improving flight operation efficiency.
Abstract
Considering similar air traffic control techniques for the present based on close historical dates is a good approach due to the unpredictability of weather and air traffic, as well as to ...increase controller efficiency. A K-prototype clustering technique and grey correlation analysis are proposed to discover similar days to address the problem of similar identification. Firstly, the weather and air traffic datasets are used to create a set of features broken down into numerical and categorical attributes. Secondly, the historical data are clustered using the K-prototype clustering, which is then paired with grey correlation analysis to identify days similar to the reference day and examine the traffic management initiatives employed on that day. Finally, the research uses actual weather information and aircraft schedules from Nanjing Lukou International Airport as examples. The outcomes demonstrate that the similar days picked by the model are representative and can serve as a foundation for airport controllers' decision-making.
Abstract
The update and iteration of the airport facilities completed in the runway operation system raise a request for more scientific control operation restrictions. In the old, optimized method ...of flight slot, no consideration was given to the runway operation strategy. As a result, the flight slot failed to meet the operation restriction and would incur unavoidable delays. This paper sets the research objective as the system composed of an apron, runway entrance and exit, and parallel runway. It focuses on matching the corresponding relationship between time and space of flights in the studied system. It establishes three flight slot optimization models to meet the requirements of isolated operation, semi-mixed operation, and mixed operation, respectively. On a practical level, the computer simulation software AirTOp is employed for simulation verification in the example of Wuhan Tianhe Airport. The results show that the delay in the isolation operation mode is reduced by about 59%, the semi-mixed operating mode reduces delays by about 48%, and mixed operating mode delays are reduced by approximately 52%. Therefore, it proves its feasibility of effective reduction in overall delay and its ability to provide decision support for the allocation of the flight time resource in parallel dual runway airports.
Limpets are marine mollusks that use mineralized teeth, one of the hardest and strongest biomaterials, to feed on algae on intertidal rocks. However, most of studies only focus on the ultrastructure ...and chemical composition of the teeth while the molecular information is largely unknown, limiting our understanding of this unique and fundamental biomineralization process. The study investigates the microstructure, proteomics, and crystallization in the teeth of limpet Cellana toreuma. It is found that the limpets formed alternatively tricuspid teeth and unicuspid teeth. Small nanoneedles are densely packed at the tips or leading regions of the cusps. In contrast, big nanoneedles resembling chemically synthesized goethite are loosely packed in the trailing regions of the cusps. Proteins extracted from the whole radula, such as ferritin, peroxiredoxin, arginine kinase, GTPase‐Rabs, and clathrin, are identified by proteomics. A goethite‐binding experiment coupled with proteomics and RNA‐seq highlights six chitin‐binding proteins (CtCBPs). Furthermore, the extracted proteins from the cusps of radula or the framework chitin induce packing of crystals and possibly affect crystal polymorphs in vitro. This study provides insight into the unique biomineralization process in the limpet teeth at the molecular levels, which may guide biomimetic strategies aimed at designing hard materials at room temperature.
DOI: 10.1002/pmic.201800194
Limpets are marine mollusks that use mineralized teeth, one of the hardest and strongest biomaterials, to feed on algae on intertidal rocks. In article number 1800194, ...Wang et al. study the microstructure and the proteomics of the limpet teeth to better understand how the hard iron based minerals are formed.
Store-operated Ca
2+
entry (SOCE) mediated by STIM1 and Orai1 is crucial for Ca
2+
signaling and homeostasis in most cell types. 2-Aminoethoxydiphenyl borate (2-APB) is a well-described SOCE ...inhibitor, but its mechanisms of action remain largely elusive. Here, we show that 2-APB does not affect the dimeric state of STIM1, but enhances the intramolecular coupling between the coiled-coil 1 (CC1) and STIM-Orai-activating region (SOAR) of STIM1, with subsequent reduction in the formation of STIM1 puncta in the absence of Orai1 overexpression. 2-APB also inhibits Orai1 channels, directly inhibiting Ca
2+
entry through the constitutively active, STIM1-independent Orai1 mutants, Orai1-P245T and Orai1-V102A. When unbound from STIM1, the constitutively active Orai1-V102C mutant is not inhibited by 2-APB. Thus, we used Orai1-V012C as a tool to examine whether 2-APB can also inhibit the coupling between STIM1 and Orai1. We reveal that the functional coupling between STIM1 and Orai1-V102C is inhibited by 2-APB. This inhibition on coupling is indirect, arising from 2-APB’s action on STIM1, and it is most likely mediated by functional channel residues in the Orai1
N
-terminus. Overall, our findings on this two-site inhibition mediated by 2-APB provide new understanding on Orai1-activation by STIM1, important to future drug design.
Calcium influx through store-operated Ca
entry (SOCE), mediated by STIM-operated Orai channels, is crucial for many cellular functions. To dissect the molecular mechanisms underlying the process of ...STIM-Orai activation and identify regulators that modify this process, ratiometric imaging of SOCE responses in HEK cells overexpressing STIM and Orai is a routinely used method. Here we describe one commonly used procedure of monitoring SOCE activity with a ratiometric membrane-permeable dye fura-2-AM. Other ratiometric indicators suitable for SOCE measurements are also discussed.
Three kinds of nozzles normally used in industrial production are numerically simulated, and the structure of nozzle with the best jetting performance out of the three nozzles is optimized. The R90 ...nozzle displays the most optimal jetting properties, including the smooth transition of the nozzle’s inner surface. Simulation results of all sample nozzles in this study show that the helix nozzle ultimately displays the best jetting performance. Jetting velocity magnitude along Y and Z coordinates is not symmetrical for the helix nozzle. Compared to simply changing the jetting angle, revolving the jet issued from the helix nozzle creates a grinding wheel on the cleaning surface, which makes not only an impact effect but also a shearing action on the cleaning object. This particular shearing action improves the cleaning process overall and forms a wider, effective cleaning range, thus obtaining a broader jet width.
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