ARTICLE | doi:10.20944/preprints201909.0106.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: slot allocation; characteristics of slot wave; capacity setting; data feeding methods; linear integer programming
Online: 10 September 2019 (07:52:51 CEST)
Management of demand and capacity for airport operation is important. The effect of capacity setting on slot adjustment, maximum adjustment and flight delay has been extensively investigated and discussed in previous slot adjustment models. But its effect on characteristics of flight waves has not been studied deeply. At present, in order to resolve the problem that Linear Integer Programming (LIP) is limited in slot allocation due to its fast dimension growth and large memory consumption, the general practice is to optimize the slot application according to data-splitting technology. However, the relationship among data splitting method, capacity setting and characteristics of slot wave has not been investigated in detail, which limits the application of LIP in slot allocation. Through the detailed analysis and testing, we found that the waveform and amplitude of slot wave can be controlled and designed by appropriate virtual capacity settings, while the number of capacity constraints and the computing time is reduced by adopting appropriate data feeding method. Our research also provides clues for further research on the construction of the flight waves for airlines operating at specific airports in order to establish direct or indirect connectivity, and increase hit rate by using our approaches.
Subject: Mathematics & Computer Science, Numerical Analysis & Optimization Keywords: Slot Allocation, Performance Comparing, Implementation Difficulty, Linear Integer Programming
Online: 7 May 2019 (10:29:00 CEST)
The purpose of this study is to ascertain whether implementation difficulty can be used in slot allocation model as a new mechanism for slightly weakening grandfather right. According to which, a linear integer programming model is designed to compare and analyze displacement, implementation difficulty and priority with different weights. Test results show that the implementation difficulty can be significantly reduced without causing excessive displacement and disruption of existing priorities, by weight setting while declared capacity is cleared. In addition to this, whether the movements are listed in order of descending priority or not have great impact on displacement and implementation difficulty within slot allocation model. Capacity is surely a key factor affecting displacement and implementation difficulties. This study contributes to propose a new mechanism for slightly weakening grandfather right, which can help decision makers to upgrade slot allocation policies.
ARTICLE | doi:10.20944/preprints201910.0199.v1
Subject: Physical Sciences, Optics Keywords: microring resonator; inner-wall grating; slot waveguide; label-free; bulk sensing
Online: 17 October 2019 (12:40:03 CEST)
In this paper, we present and analyze a compact inner-wall grating slot microring resonator (IG-SMRR) with the footprint of less than 13 μm × 13 μm on the SOI platform for label-free sensing, which comprises a slot microring resonator (SMRR) and inner-wall grating (IG). Its detection range is significantly enhanced without the limitation of the free spectral region (FSR) owing to the combination of SMRR and IG. Structural parameters of IG and SMRR are investigated and optimized for favorable transmission properties. The simulation results shows that the IG-SMRR has an ultra-large quasi-FSR of 84.6 nm, and the concentration sensitivities of sodium chloride solutions and D-glucose solutions are up to 960.61 pm/% and 933.06 pm/%, respectively. The investigation on the combination of SMRR and IG is a valuable exploration of label-free sensing application for ultra-large detection range and ultra-high sensitivity in future.
ARTICLE | doi:10.20944/preprints202011.0525.v1
Subject: Engineering, Automotive Engineering Keywords: flexible functional device; thin film coating; slot-die; surface tension; coating gap
Online: 20 November 2020 (07:08:12 CET)
Slot-die coatings are advantageous when used for coating large-area flexible devices; in particular, the coating width can be controlled, and simultaneous multi-layer coatings can be processed. Till date, the effects of ink widening and coating gap on the coating thickness have only been considered in a few studies. To this end, we developed two mathematical models to accurately estimate the coating width and thickness considering these two effects. We used root mean square deviation (RMSD) to experimentally verify the developed method. The coating width was seen to increase and the coating thickness was seen to decrease when the coating gap was increased. Experimental results showed that the estimation performances of the coating width and thickness models were as high as 98.46 % and 95.8 %, respectively. We believe that the developed models can be useful for determining the coating conditions according to the ink properties to coat a functional layer with user-defined widths and thicknesses in both lab- and industrial-scale roll-to-roll slot-die coating processes.
ARTICLE | doi:10.20944/preprints202002.0344.v1
Subject: Engineering, Civil Engineering Keywords: flow regime transition; finite volume methods; numerical oscillations; numerical viscosity; Preissmann slot model
Online: 24 February 2020 (03:38:08 CET)
Transition between free-surface and pressurized flows is an crucial phenomenon in many hydraulic systems, including water distribution systems, urban drainage systems, etc. During the transition, the force exerted on the structures changes drastically, thus it is meaningful to simulate this process. However, severe numerical oscillations are widely observed behind filling-bores, causing unphysical pressure variations and even computation failure. In this paper, some oscillation-suppressing approaches are reviewed and evaluated on a benchmark model. Then a new oscillation-suppressing approach is proposed to admit numerical viscosity when the water surface is at proximity of conduct roof which has first order accuracy. This approach adds numerical viscosity when water surface is at the proximity of conduct roof. It can sufficiently suppress numerical oscillations under an acoustic wave speed of 1000m/s and is simple to apply. In comparison with two experiments, the simulation results of this method show good agreement and little numerical oscillations. The results in this paper can help readers to choose an appropriate oscillation-suppressing method to improve the robustness and accuracy of flow regime transition simulations.
ARTICLE | doi:10.20944/preprints202001.0165.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electrical motors; Slot Filling factor; Optimization Algorithm; Windings; Magnetic Wire; Filling Factor Optimization
Online: 16 January 2020 (10:54:48 CET)
The continuous development in the field of industrial automation and electric mobility has led to the need for more efficient electrical machines with high power density. The improvement of electrical machines slot filling factors is one of the measures to satisfy these requirements. In recent years, this topic has aroused greater interest in the industrial sector, since the evolution of the winding technological manufacturing processes allows an economically sustainable realization of ordered winding arrangements, rather than random ones. Moreover, the manufacture of electrical machines windings must be preceded by an accurate design phase in which it is possible to evaluate the maximum slot filling factor obtainable for a given wire shape and for its dimensions. For this purpose, this paper presents an algorithmic approach for the evaluation of maximum slot filling factors in electrical machines under ideal geometric premise. In particular, this algorithm has a greater degree of flexibility with respect to the algorithm approaches found in the literature, since the study has been extended to round, rectangular and hexagonal wire sections. Furthermore, the slot filling factor calculation was carried out both for standard and non-standard slots. The algorithmic approach proposed can be considered as an additional useful tool for the fast design of electrical machine windings.
ARTICLE | doi:10.20944/preprints201703.0113.v1
Subject: Engineering, Automotive Engineering Keywords: automotive applications; concentrated windings; eddy current losses; fractional-slot windings; interior permanent-magnet motors
Online: 16 March 2017 (09:02:53 CET)
This paper analyzes and compares models for predicting average magnet losses in interior permanent-magnet motors with fractional-slot concentrated windings due to harmonics in the armature reaction (assuming sinusoidal phase currents). Particularly, loss models adopting different formulations and solutions to the Helmholtz equation to solve for the eddy currents are compared to a simpler model relying on an assumed eddy-current distribution. Boundaries in terms of magnet dimensions and angular frequency are identified (numerically and using an identified approximate analytical expression) to aid the machine designer whether the more simple loss model is applicable or not. The assumption of a uniform flux-density variation (used in the loss models) is also investigated for the case of V-shaped and straight interior permanent magnets. Finally, predicted volumetric loss densities are exemplified for combinations of slot and pole numbers common in automotive applications.
ARTICLE | doi:10.20944/preprints202011.0465.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: coating defect; electrolyte layer; temperature; thermal deformation; roll-to-roll slot-die coating systems; wrinkle
Online: 18 November 2020 (10:43:39 CET)
In roll-to-roll (R2R) processing, uniformity of the web is a crucial factor that can guarantee high coating quality. To understand web defects due to thermal deformation, we analyzed the effects of web unevenness on the coating quality of an yttria-stabilized zirconia (YSZ) layer, a brittle electrolyte of solid oxide fuel cells (SOFCs). We used finite element analysis to analyze the thermal and mechanical deformations at different drying temperatures. A YSZ layer was also coated using R2R slot-die coating to observe effects of web unevenness on the coating quality. It was seen that web unevenness was generated by thermal deformation due the conduction and convection heat from the dryer. Owing to varying web unevenness with time, the YSZ layer developed cracks. At higher drying temperatures, more coating defects having larger widths were generated. Results indicated that web unevenness at the coating section led to coating defects, which could damage the SOFC and decrease its yield in the R2R process. From this study, we suggest that coating defects, generated by the web unevenness owing to the convection and conduction heat, should be considered for the high-volume production of brittle electrolytes using the R2R process.
COMMUNICATION | doi:10.20944/preprints201904.0220.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: array antenna Microstrip Patch Antenna (MPA); slot antenna; metamaterial; Multiple-Output Multiple-Input (MIMO); radar; RFID systems; millimetre-wave band
Online: 19 April 2019 (11:36:12 CEST)
A novel configuration for a super-wide impedance planar antenna is presented based on a 2 × 2 microstrip patch antenna (MPA). The antenna comprises a symmetrical arrangement of four-square patches that are interconnected to each other with cross-shaped high impedance microstrip lines. The antenna array is exciting through a single feedline connected to one of the patches. The proposed antenna array configuration overcomes the main drawback of conventional MPA of narrow bandwidth that is typically <5%. The antenna exhibits a super-wide frequency bandwidth from 20 GHz to 120 GHz for S11<−15 dB, which corresponds to a fractional bandwidth of 142.85%. The antenna’s performance of bandwidth, impedance match, and radiation gain were enhanced by etching slots on the patches. The slotted microstrip patch essentially acts like a left-handed capacitance to exhibit metamaterial properties over a given frequency range. With the inclusion of the slot the maximum radiation gain and efficiency of the MPA have increased to 15.11 dBi and 85.79% at 80 GHz, which show an improvement of 2.58 dBi and 12.54%, respectively. The dimension of each patch antenna is 30 × 30 mm2. The results show that the proposed MPA is useful for various communications existing and emerging systems such as ultra-wideband (UWB) communications, RFID systems, massive multiple-output multiple-input (MIMO) for 5G, and radar systems.