scholarly journals Post COVID-19 precautions management in small-scale airports: Evaluation of check-in process in Erkilet airport by simulation

2020 ◽  
Vol 10 (2) ◽  
pp. 77
Author(s):  
Elif Bolat ◽  
Savaş S. Ateş
Keyword(s):  
Social Distance ◽  
Simulation Method ◽  
Simulation Program ◽  
Aviation Industry ◽  
Small Scale ◽  
Research Information ◽  
Density Peak ◽  
Airport Management ◽  
First Time ◽  
Management Issues

Purpose: The number of passengers, luggage, and cargo served at the airports increases at certain times due to flight density (peak hours). Due to the long queues at check-in desk during peak hours, there may be delays in flight operation processes. In addition, it is estimated that check-in queue times will increase even more in accordance with Covid-19 social distance rules.The aim of the study is to calculate the possible effects of Covid-19 measures on check-in queues at small-scale airports. For this purpose, the number of check-in desks that should be opened at peak hours was evaluated by simulation method at Erkilet airport.Design/methodology/approach: In the first part of the study, the effects of Covid-19 measures on the aviation industry and airport management issues are presented with the literature research. Information about Erkilet airport was collected by using qualitative research method and the intensity experienced during peak hours was simulated in the ARENA-TRIAL simulation program. Two 3D scenarios were prepared, including the pre and past COVID-19 social distance constraints.Findings: In the analysis section of the research, check-in queue times and staff productivity were calculated for both scenarios. In the calculations, comments were made regarding the problems that may occur during the peak hours of the airport within the scope of the check-in desk and COVID-19 social distance constraints. Based on the analysis outputs of the simulation program, recommendations were made for small-scale airports.Originality/value: The effect of COVID-19 on the check-in process in small-scale airports was examined for the first time with simulation method.

scholarly journals On the Relationship between Low Latitude Scintillation Onset and Sunset Terminator over Africa

2021 ◽  
Vol 13 (11) ◽  
pp. 2087
Author(s):  
Mogese Wassaie Mersha ◽  
Elias Lewi ◽  
Norbert Jakowski ◽  
Volker Wilken ◽  
Jens Berdermann ◽  
...  
Keyword(s):  
Moving Boundary ◽  
Occurrence Rate ◽  
Scintillation Index ◽  
Small Scale ◽  
Bahir Dar ◽  
Remarkable Change ◽  
Equatorial Africa ◽  
Night Side ◽  
Solar Terminator ◽  
First Time

The solar terminator is a moving boundary between day-side and night-side regions on the Earth, which is a substantial source of perturbations in the ionosphere. In the vicinity of the solar terminator, essential parameters like S4 index measurements are widely analyzed in order to monitor and predict perturbations in the ionosphere. The utilization of the scintillation index S4 is a well-accepted approach to describe the amplitude/intensity fluctuation of a received signal, predominantly caused by small-scale irregularities of the ionospheric plasma. We report on the longitudinal daily and seasonal occurrence of GNSS signal scintillations, using the data derived from the GNSS stations in Bahir Dar, Ethiopia, Lomé, Togo and Dakar, Senegal. The observed seasonal climatology of GNSS signal scintillations in equatorial Africa is adequately explained by the alignment of the solar terminator and local geomagnetic declination line. It should be pointed out that the strongest scintillations are most frequently observed during the time when the solar terminator is best aligned with the geomagnetic declination line. At all three stations, the comparison of computational and observational results indicated that the scintillation activity culminated around equinoxes in the years 2014, 2015 and 2016. Comparatively, the western equatorial Africa sector has the most intense, longest-lasting, and highest scintillation occurrence rate in equinoctial seasons in all three years. For the first time, we show that the seasonal variation of the scintillation peaks changes systematically from west to east at equatorial GNSS stations over Africa. A detailed analysis of the solar day–night terminator azimuth at ionospheric heights including the time equation shows that the scintillation intensity has a maximum if the azimuth of the terminator coincides with the declination line of the geomagnetic field. Due to the remarkable change of the declination by about 10° at the considered GNSS stations, the distance between scintillation peaks increases by 46 days when moving westward from the Bahir Dar to the Dakar GNSS station. The observations agree quite well with the computational results, thus confirming Tsunoda’s theory.

Corrosion Testing of Armour Wire in Simulated Annulus Environments of Flexible Pipelines: An Update

2003 ◽  
Author(s):  
Richard Clements ◽  
Andrew D. Ethridge
Keyword(s):  
Deionized Water ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Scale Test ◽  
Condensed Water ◽  
Test Cells ◽  
Sour Service ◽  
First Time ◽  
Permeation Models

This paper describes further investigations, utilising small scale test cells, into the general corrosion which can occur on wires within the inherent annulus space in a flexible pipe, particularly, and for the first time, in a sour service (H2S containing) environment. The work enhances data presented previously in 2002. Tests have been performed in cells specifically designed to simulate, as closely as possible, the environment and confines of a flexible pipe annulus, using solutions of both deionized water and seawater (to represent seawater flooding and condensed water). The systems were saturated with CO2 and H2S to simulate permeation of gases through the polymer pressure sheath (as predicted by validated permeation models). Weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated annulus environments and metallography was undertaken to characterise the corrosion and check for HIC/SOHIC.

scholarly journals “Audience exchange”: cultivating peer-to-peer dialogue at unfamiliar arts events

2017 ◽  
Vol 7 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Stephanie Pitts ◽  
Jonathan Gross
Keyword(s):  
Peer Learning ◽  
Peer To Peer ◽  
Small Scale ◽  
Exchange Method ◽  
Audience Engagement ◽  
Content Type ◽  
Peer Dialogue ◽  
Targeted Marketing ◽  
Audience Development ◽  
First Time

Purpose The purpose of this paper is to demonstrate the usefulness of the “audience exchange” approach for audience development and research, and to highlight the insights offered by peer-to-peer dialogue in understanding experiences of unfamiliar arts. Design/methodology/approach Using a case study with contemporary arts audiences, and setting this in the wider context of studies with other first-time attenders at a range of arts events, the paper explores the use of the “audience exchange” method, in which facilitated conversations after performance events allow newcomers to reflect upon and deepen their first-time encounters with live arts. Findings The study demonstrates the way in which conversations about arts events can enrich audience experience, and shows how participants use exploratory and emotional language to articulate their understanding of unfamiliar arts events. Peer-to-peer learning occurs through these conversations, in ways that could be further supported by arts organisations as a valuable tool for audience development. The audience exchange discussions also reveal the varieties of participation from “drifting” to full attention that are all part of audience engagement. Research limitations/implications This is a small-scale, qualitative study, and the method has potential to be tested in future studies with a greater variety of participants (e.g. younger or more ethnically diverse groups). Practical implications Use of the audience exchange for enriching experiences of first-time attendance could be adopted by arts organisations as a regular part of their audience engagement. Greater understanding of how new audience members draw on prior cultural experiences in finding the language to articulate their first impressions of an unfamiliar arts event could be valuable for targeted marketing and increasing accessibility. Originality/value The originality of this study lies in its elaboration of the audience exchange method, and its focus on the language and peer-to-peer learning evident in the facilitated post-performance discussions.

Experimental and Analytical Studies on Flexure Pivot Tilting Pad Gas Bearings With Dampers Applied to Radially Compliant Pads

2009 ◽  
Author(s):  
Daejong Kim ◽  
Aaron Rimpel
Keyword(s):  
Simulation Method ◽  
Analysis Tool ◽  
Primary Analysis ◽  
Successful Operation ◽  
Gas Bearings ◽  
Viscoelastic Dampers ◽  
Thermal Growth ◽  
Tilting Pad ◽  
Rotor Bearing ◽  
First Time

Hydrodynamic flexure pivot tilting pad gas bearings (FPTPGBs) can enable successful operation of oil-free microturbomachinery, and FPTPGBs with radially compliant pads (FPTPGB-Cs) permit rotor centrifugal and/or thermal growth to exceed original bearing clearances and achieve higher speeds. This work presents the experimental and analytical study of such bearings and the application of dampers behind the pad radial compliance structure. A time domain orbit simulation method was implemented as the primary analysis tool to predict rotor-bearing response to imbalance, the presence and location of critical speeds, etc., and compare with test results. Experiments demonstrate the stable hydrodynamic operation of FPTPGBs with a ∼28.6 mm, 0.8 kg rotor above 120 krpm for the first time. The rotor-bearing system was intentionally destabilized in tests by increasing bearing clearances, and viscoelastic dampers added behind the FPTPGB pads delayed the onset of subsynchronous vibrations (from 43 krpm without damper to above 50 krpm with damper). Midrange subsynchronous vibrations of the destabilized system initiated at ∼20 krpm were suppressed by ∼25 krpm due to the stabilizing effect of rotor centrifugal growth. The viscoelastic dampers had a negligible effect on suppressing these midrange subsynchronous vibrations in experiments, but this was not demonstrated in simulations, presumed to be due to much lower stiffness contribution of the damper at lower frequencies.

scholarly journals Transient brightenings in the quiet Sun detected by ALMA at 3 mm

2020 ◽  
Vol 638 ◽  
pp. A62 ◽  
Author(s):  
A. Nindos ◽  
C. E. Alissandrakis ◽  
S. Patsourakos ◽  
T. S. Bastian
Keyword(s):  
Solar Atmosphere ◽  
Power Law ◽  
Small Scale ◽  
Solar Chromosphere ◽  
Average Intensity ◽  
Quiet Sun ◽  
Brightness Temperatures ◽  
Weak Preference ◽  
Thermal Origin ◽  
First Time

Aims. We investigate transient brightenings, that is, weak, small-scale episodes of energy release, in the quiet solar chromosphere; these episodes can provide insights into the heating mechanism of the outer layers of the solar atmosphere. Methods. Using Atacama Large Millimeter/submillimeter Array (ALMA) observations, we performed the first systematic survey for quiet Sun transient brightenings at 3 mm. Our dataset included images of six 87″ × 87″ fields of view of the quiet Sun obtained with angular resolution of a few arcsec at a cadence of 2 s. The transient brightenings were detected as weak enhancements above the average intensity after we removed the effect of the p-mode oscillations. A similar analysis, over the same fields of view, was performed for simultaneous 304 and 1600 Å data obtained with the Atmospheric Imaging Assembly. Results. We detected 184 3 mm transient brightening events with brightness temperatures from 70 K to more than 500 K above backgrounds of ∼7200 − 7450 K. All events showed light curves with a gradual rise and fall, strongly suggesting a thermal origin. Their mean duration and maximum area were 51.1 s and 12.3 Mm2, respectively, with a weak preference of appearing at network boundaries rather than in cell interiors. Both parameters exhibited power-law behavior with indices of 2.35 and 2.71, respectively. Only a small fraction of ALMA events had either 304 or 1600 Å counterparts but the properties of these events were not significantly different from those of the general population except that they lacked their low-end energy values. The total thermal energies of the ALMA transient brightenings were between 1.5 × 1024 and 9.9 × 1025 erg and their frequency distribution versus energy was a power law with an index of 1.67 ± 0.05. We found that the power per unit area provided by the ALMA events could account for only 1% of the chromospheric radiative losses (10% of the coronal ones). Conclusions. We were able to detect, for the first time, a significant number of weak 3 mm quiet Sun transient brightenings. However, their energy budget falls short of meeting the requirements for the heating of the upper layers of the solar atmosphere and this conclusion does not change even if we use the least restrictive criteria possible for the detection of transient brightenings.

scholarly journals THE ADAPTED YAM MINISETT TECHNIQUE FOR PRODUCING CLEAN SEED YAMS (DIOSCOREA ROTUNDATA): AGRONOMIC PERFORMANCE AND VARIETAL DIFFERENCES UNDER FARMER-MANAGED CONDITIONS IN NIGERIA

2014 ◽  
Vol 51 (3) ◽  
pp. 467-482 ◽  
Author(s):  
STEPHEN MORSE ◽  
NORA McNAMARA
Keyword(s):  
Small Scale ◽  
Agronomic Performance ◽  
Economic Returns ◽  
Dioscorea Rotundata ◽  
Pesticide Treatment ◽  
Planting Material ◽  
Clean Seed ◽  
Small Scale Farmers ◽  
Major Factors ◽  
First Time

SUMMARYWhite yam (Dioscorea rotundata) is a major root crop grown throughout West Africa but one of the major factors that limits its production is the availability of good quality planting material. This paper described the results of farmer-managed demonstration plots established in 2012 and 2013 designed to promote the Adapted Yam Minisett Technique (AYMT) in Nigeria. The AYMT was developed between 2005 and 2008 to produce quality seed yam tubers at a cost that is viable for small-scale farmers. Since its development the agronomic performance of AYMT has not been explored across a large sample of farmers, and neither has there been any attempt to explore possible varietal effects although farmers have often alluded to this. This papers seeks to address these gaps in the literature and the results suggest that the AYMT does succeed in producing seed yams of the required size and the economic returns are also good. Results also suggest that there is a varietal affect with AYMT, including a significant interaction with pesticide treatment; the first time this has been demonstrated.

The Use of Computer Simulation of Merged Variation to Predict Rework Levels on Ship's Hull Blocks

1988 ◽  
Vol 4 (03) ◽  
pp. 155-168
Author(s):  
R.L. Storch ◽  
P.J. Giesy
Keyword(s):  
Computer Simulation ◽  
Probability Distribution ◽  
Subsequent Development ◽  
Simulation Method ◽  
Simulation Program ◽  
Modular Construction ◽  
Accuracy Control ◽  
Probability Curve ◽  
Productivity Losses ◽  
Computer Simulation Program

In the modular construction of ships, significant productivity losses can occur during the erection stage, when the modules, or hull blocks, are joined together. Frequently, adjacent blocks do not fit together properly, and rework of one or both of the mating block interfaces is necessary to correct the problem. The specific cause of rework is the variation of plate edges at the block interface, which is itself a cumulative product of numerous manufacturing variations inherent in hull block construction. Variation in manufacturing is unavoidable, but not uncontrollable. The application of accuracy control techniques in shipbuilding has proven that a statistical analysis of variation makes possible an accurate prediction of its effects. This paper presents an examination of block interface variation, and the subsequent development of a computer simulation method of predicting rework levels on those blocks. The complex interaction of all the edges' random variations at the block interface gives rise to a unique rework probability distribution. This probability distribution is evaluated by means of the computer simulation program, which provides estimates of the average rework anticipated, the shape of the probability curve, and other parameters. Similar predictions are also available for cost and labor of required rework. In addition to predicting rework levels, the simulation program can be a useful tool for reducing those levels.

scholarly journals Wobbly discs – corrugations seen in the dust lanes of edge-on galaxies

2020 ◽  
Vol 495 (4) ◽  
pp. 3705-3714
Author(s):  
Chaitra A Narayan ◽  
Ralf-Jürgen Dettmar ◽  
Kanak Saha
Keyword(s):  
Stability Analysis ◽  
Small Scale ◽  
Host Galaxies ◽  
Lower Mass ◽  
Limited Sample ◽  
Unsharp Masking ◽  
Bending Waves ◽  
First Time ◽  
Larger Sample ◽  
Disc Galaxies

ABSTRACT We report the detection of small-scale bending waves, also known as corrugations, in the dust lanes of five nearby edge-on disc galaxies. This phenomenon, where the disc mid-plane bends to become wavy, just as in warps but on a smaller scale, is seen here for the first time, in the dust lanes running across the discs. Because they are seen in absorption, this feature must be present in the dust disc in the outskirts of these galaxies. We enhance the visibility of these features using unsharp masking, trace the dust mid-plane across the disc, measure the corrugation amplitude by eye and the corrugation wavelength using Fourier analysis. The corrugation amplitude is found to be in the range of 70–300pc and the wavelengths lie between 1 and 5 kpc. In this limited sample, we find that the amplitude of the corrugations tends to be larger for lower mass galaxies, whereas the wavelength of corrugation does not seem to depend on the mass of host galaxies. Linear stability analysis is performed to find out the dynamical state of these dust discs. Based on WKB analysis, we find that the dust corrugations in about half of our sample are stable. Further analysis, on a larger sample would be useful to strengthen the above results.

scholarly journals Nearest-Neighbour-Induced Isolation Similarity and Its Impact on Density-Based Clustering

2019 ◽  
Vol 33 ◽  
pp. 4755-4762 ◽  
Author(s):  
Xiaoyu Qin ◽  
Kai Ming Ting ◽  
Ye Zhu ◽  
Vincent CS Lee
Keyword(s):  
Clustering Algorithm ◽  
Distance Measure ◽  
Nearest Neighbour ◽  
Density Peak ◽  
Density Based Clustering ◽  
New Type ◽  
Density Peak Clustering ◽  
The Impact ◽  
First Time ◽  
Tree Method

A recent proposal of data dependent similarity called Isolation Kernel/Similarity has enabled SVM to produce better classification accuracy. We identify shortcomings of using a tree method to implement Isolation Similarity; and propose a nearest neighbour method instead. We formally prove the characteristic of Isolation Similarity with the use of the proposed method. The impact of Isolation Similarity on densitybased clustering is studied here. We show for the first time that the clustering performance of the classic density-based clustering algorithm DBSCAN can be significantly uplifted to surpass that of the recent density-peak clustering algorithm DP. This is achieved by simply replacing the distance measure with the proposed nearest-neighbour-induced Isolation Similarity in DBSCAN, leaving the rest of the procedure unchanged. A new type of clusters called mass-connected clusters is formally defined. We show that DBSCAN, which detects density-connected clusters, becomes one which detects mass-connected clusters, when the distance measure is replaced with the proposed similarity. We also provide the condition under which mass-connected clusters can be detected, while density-connected clusters cannot.

scholarly journals Optimisation of confinement in a fusion reactor using a nonlinear turbulence model

2018 ◽  
Vol 84 (2) ◽  
Author(s):  
E. G. Highcock ◽  
N. R. Mandell ◽  
M. Barnes ◽  
W. Dorland
Keyword(s):  
First Principles ◽  
Figure Of Merit ◽  
Large Scale ◽  
Unit Volume ◽  
Fusion Reactor ◽  
Small Scale ◽  
Zonal Flows ◽  
Novel Approach ◽  
First Time ◽  
Turbulent Cascade

The confinement of heat in the core of a magnetic fusion reactor is optimised using a multidimensional optimisation algorithm. For the first time in such a study, the loss of heat due to turbulence is modelled at every stage using first-principles nonlinear simulations which accurately capture the turbulent cascade and large-scale zonal flows. The simulations utilise a novel approach, with gyrofluid treatment of the small-scale drift waves and gyrokinetic treatment of the large-scale zonal flows. A simple near-circular equilibrium with standard parameters is chosen as the initial condition. The figure of merit, fusion power per unit volume, is calculated, and then two control parameters, the elongation and triangularity of the outer flux surface, are varied, with the algorithm seeking to optimise the chosen figure of merit. A twofold increase in the plasma power per unit volume is achieved by moving to higher elongation and strongly negative triangularity.

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