Quantitative evaluation of passenger terminal orientation

When passenger terminal layout is being decided, one of the important aspects to consider is how the passenger orients himself during his visit to the terminal and his movements through it, i.e. terminal orientation. Among other things, this terminal characteristic results from visibility, or the visual connectivity between elements and spaces. The paper proposes an amendment and modification to the known method for the quantitative evaluation of terminal orientation which uses an oriented network to describe the connectivity of elements (terminal orientation). The amendment and modification of the method consists of proposing that during evaluation only visual connections that have functional meaning should be considered, rather than all visual connections. A further modification is the introduction of different weights for different connections. The example presented in the paper considers an airport terminal building.     

Environmental changes in the western Black Sea related to anthropogenic and natural conditions

The Black Sea northwestern shelf (NWS) ecosystem has been subjected to the strongest anthropogenic pressure of the entire Black Sea as about 80% of the freshwater runoff is discharged there.This paper presents a review of the global environmental changes related mainly to increased eutrophication in the western Black Sea basin.A case study (CoMSBlack 92a cruise) attempts to highlight the interaction of some natural and anthropogenic factors responsible for specific chemical and biological features in the western Black Sea environment. The significance of processes located near the Danube river mouth, which, due to their relatively small space scale, have not been recognized before, is clarified. Hydrological processess of specific importance to the distribution and transformation of antropogenic inputs are river plume dynamics, coastal upwelling and mixing and downwelling over the shelf break and slope in this part of the basin. A layer of low hydrological variability (“conservative layer”) appears to be a natural feature of the area, hypothesized to precondition specific biological and chemical processes there.The results suggest that the interplay between the Danube anthropogenic nutrient load with the natural hydrological fronts and gradients provides opportunities for enhanced biological activity thus contributing to the global environmental changes in the Black Sea NWS.     

Discrete Adaptive Active Suspension for Hardware Implementation

This paper presents a discrete adaptive control approach for an active suspension. The study involves formulation of an active suspension as a digital controller problem involving the time delays. A nonlinear time varying (NTV), single input single output (SISO) suspension model is considered for the analysis. A discrete model reference adaptive control (DMRAC) approach with recursive least square (RLS) estimation is used to form the controller. The controller is designed to maintain the static equilibrium irrespective of dynamic load variations as a disturbance force on the model. Simulation results for deterministic and stochastic inputs are presented to substantiate the approach. Results indicate good performance of adaptive controller even for large dynamic variations of the model and has the potential for a successful hardware implementation.     

Preloading of independent leg units at locations with difficult seabed conditions

This paper, based on analyses of case histories, reviews soil conditions causing sudden uncontrolled leg penetrations, together with site data needed to plan safe installations of jack-up drilling units. Punch-through-like failure in uniform clay profile is analysed. Preloading procedures aimed at minimizing potential damage to the unit are suggested and discussed.     

On the kinematics and quantum dynamics of traffic flow

The hydrodynamic model of traffic flow is presented and interpreted. Traffic dimensions are defined for the dynamic entities of flow and the behaviour of congestive and dispersive flow is discussed dependent on the value of the local traffic transfer number, R. The wave equation is one example of dispersive flow, where quantum numbers define the condition of free flow at the endpoints of the link. The Schrödinger equation is defined and applied to the study of the cyclic work journey and the problem of traffic lights as an harmonic oscillator.     

Automatic control of clutches and simulations for parallel hybrid vehicles

This paper is a continuation of a previous paper titled ??Modeling and Model Predictive Control for Hybrid Vehicle?? published on IJAT/2011 describing a mathematical model and design for a model predictive controller for tracking speeds and simulations. The present paper further describes a fuzzy logic controller for the smooth and quick engagement of an automatic clutch. The described controller uses both fuzzy logic and slip control algorithms to enable automatic clutch engagement. Clutch engagement and comprehensive simulations for the hybrid vehicle are conducted in MATLAB R2009s. The research described herein offers theoretical solutions for how to better control clutch slip and engagement within realistic parameters used for hybrid vehicles. Algorithms and operations of this fuzzy logic controller can be implemented in electronic control units for automatic clutch engagements and gear-shifting processes.     

Mixing over the steep side of the Cycladic Plateau in the Aegean Sea

Intensive microstructure sampling over the southern slope of the Cycladic Plateau found very weak mixing in the pycnocline, centered on a thin minimum of diapycnal diffusivity with Kρ=1.5×¹⁰−6 m² s^− 1. Below the pycnocline, Kρ increased exponentially in the bottom 200 m, reaching 1 × 10^− 4 m² s^− 1 a few meters above the bottom. Near-bottom mixing was most intense where the bottom slope equaled the characteristic slope of the semi-diurnal internal tide. This suggests internal wave scattering and/or generation at the bottom, a conclusion supported by near-bottom dissipation rates increasing following rising winds and with intensifying internal waves. Several pinnacles on the slope were local mixing hotspots. Signatures included a vertical line of strong mixing in a pinnacle's wake, an hydraulic jump or lee wave over a downstream side of the summit, and a ‘beam’ sloping upward at the near-inertial characteristic slope. Because dissipation rate averages were dominated by strong turbulence, ?/νN² > 100, the effect on Kρ of alternate mixing efficiencies proposed for this range of turbulent intensity is explored.     

Mathematical model for optimising the sequence for clearing snow from the manoeuvring area during winter operations

This article considers the optimisation of the sequence for clearing snow from stretches of the manoeuvring area of an airport. This issue involves the optimisation of limited resources to remove snow from taxiways and runways thereby leaving them in an acceptable condition for operating aircraft. The airfield is divided into subsets of significant stretches for the purpose of operations and target times are established during which these are open to aircraft traffic. The document contains several mathematical models each with different functions, such as the end time of the process, the sum of the end times of each stretch and gap between the estimated and the real end times. During this process, we introduce different operating restrictions on partial fulfilment of the operational targets as applied to zones of special interest, or relating to the operation of the snow‐clearing machines. The problem is solved by optimisation based on linear programming. The article gives the results of the computational tests carried out on five distinct models of the manoeuvring area, which cover increasingly complex situations and larger areas. The mathematical model is particularised for the case of the manoeuvring area of Adolfo Suarez Madrid—Barajas Airport. Copyright © 2016 John Wiley & Sons, Ltd.

Highlights
• Optimal sequence for clearing snow from the manoeuvring area of an airport.
• Contains optimising algorithms solved using CPLEX LP‐based tree search.
• Restrictions on partial fulfilment of operational targets applied to subsets of significant stretches, used for planning the operation of snow‐clearing machines.
• Model applied to the case of the manoeuvring area of Adolfo Suárez Madrid Barajas Airport.
• Conclusions are given on the results of the computational tests carried out. There are five models of the manoeuvring area which cover increasingly complex situations and larger areas.

     

Numerical analysis of the dynamic interaction between wheel set and turnout crossing using the explicit finite element method

A three-dimensional (3-D) explicit dynamic finite element (FE) model is developed to simulate the impact of the wheel on the crossing nose. The model consists of a wheel set moving over the turnout crossing. Realistic wheel, wing rail and crossing geometries have been used in the model. Using this model the dynamic responses of the system such as the contact forces between the wheel and the crossing, crossing nose displacements and accelerations, stresses in rail material as well as in sleepers and ballast can be obtained. Detailed analysis of the wheel set and crossing interaction using the local contact stress state in the rail is possible as well, which provides a good basis for prediction of the long-term behaviour of the crossing (fatigue analysis). In order to tune and validate the FE model field measurements conducted on several turnouts in the railway network in the Netherlands are used here. The parametric study including variations of the crossing nose geometries performed here demonstrates the capabilities of the developed model. The results of the validation and parametric study are presented and discussed.