Integer programming based solution approaches for the train dispatching problem

Railroads face the challenge of competing with the trucking industry in a fastpaced environment. In this respect, they are working toward running freight trains on schedule and reducing travel times. The planned train schedules consist of departure and arrival times at main stations on the rail network. A detailed timetable, on the other hand, consists of the departure and arrival times of each train in each track section of its route. The train dispatching problem aims to determine detailed timetables over a rail network in order to minimize deviations from the planned schedule. We provide a new integer programming formulation for this problem based on a spacetime network; we propose heuristic algorithms to solve it and present computational results of these algorithms. Our approach includes some realistic constraints that have not been previously considered as well as all the assumptions and practical issues considered by the earlier works

Determination of Chemisorption Probabilities of Hydrogen Molecules on a Nickel Surface by Artificial Neural Network

Dissociative chemisorption probabilities for H2(v, j) + Ni(100) collision systems have been estimated by using Artificial Neural Network (ANN). For training, previously determined probability values via molecular dynamics simulations have been used. Performance of the ANN, for predicting any quantities in the molecule-surface interaction, has been investigated. Effects of the surface sites and the rovibrational states of the molecule on the process are analyzed. The results are in good agreement with the related previous studies

Structural and energetic properties of nickel clusters: 2≤N≤1502 \le N \le 150

The four most stable structures of Ni$_N$ clusters with $N$ from 2 to 150 have been determined using a combination of the embedded-atom method in the version of Daw, Baskes and Foiles, the {\it variable metric/quasi-Newton} method, and our own {\it Aufbau/Abbau} method. A systematic study of energetics, structure, growth, and stability of also larger clusters has been carried through without more or less severe assumptions on the initial geometries in the structure optimization, on the symmetry, or on bond lengths. It is shown that cluster growth is predominantly icosahedral with $islands$ of {\it fcc}, {\it tetrahedral} and {\it decahedral} growth. For the first time in unbiased computations it is found that Ni$_{147}$ is the multilayer (third Mackay) icosahedron. Further, we point to an enhanced ability of {\it fcc} clusters to compete with the icosahedral and decahedral structures in the vicinity of N=79. In addition, it is shown that conversion from the {\it hcp}/anti-Mackay kind of icosahedral growth to the {\it fcc}/Mackay one occurs within a transition layer including several cluster sizes. Moreover, we present and apply different analytical tools in studying structural and energetic properties of such a large class of clusters. These include means for identifying the overall shape, the occurrence of atomic shells, the similarity of the clusters with, e.g., fragments of the {\it fcc} crystal or of a large icosahedral cluster, and a way of analysing whether the $N$-atom cluster can be considered constructed from the $(N-1)$-atom one by adding an extra atom. In addition, we compare in detail with results from chemical-probe experiment. Maybe the most central result is that first for clusters with $N$ above 80 general trends can be identified.Comment: 37 pages, 11 figure

Distributive politics and regional development: assessing the territorial distribution of Turkey’s public investment

Turkey is often perceived as a country with low bureaucratic capacity and prone to political manipulation and ‘pork-barrel’. This article tests whether this is the case, by analysing the extent to which politics, rather than equity and efficiency criteria, have determined the geographical allocation of public investment across the 81 provinces of Turkey between 2005 and 2012. The results show that although the Turkish government has indeed channelled public expenditures to reward its core constituencies, socioeconomic factors remained the most relevant predictors of investment. Moreover, in contrast to official regional development policy principles, we uncover the concentration of public investment in areas with comparatively higher levels of development. We interpret this as the state bureaucracy’s intentional strategy of focussing on efficiency by concentrating resources on ‘the better off among the most in need’

Architecture and Gender : Lessons from Building Archaeology in Africa

Peer reviewe

Smooth muscle cell function and organization of the resistance artery wall

Remodeling of the vascular wall occurs in several cardiovascular pathologies. A structural change in diameter necessarily involves reorganization in both cellular and extracellular matrix components. The significance of matrix remodeling in vascular pathologies is well appreciated, while plasticity of vascular smooth muscle cells (SMC) received less attention. Such contractile plasticity is defined as a change of the diameter-dependent capacity for active force generation. The aim of this thesis is to investigate how small arteries maintain their stability and functionality, from a biomechanical perspective, during physiological and pathological remodeling. We propose that vascular SMC plasticity is an important process in inward remodeling of small arteries. The most important findings were; the contractile properties of SMCs in resistance vessels are subject to rapid changes. Such contractile plasticity is influenced by externally imposed vasoconstriction and strain. Vasoconstrictors and specifically ET-1 induced inward SMC plasticity in small arteries while chronic strain results a shift of tension generating capacity to larger diameters. This process may maintain optimal matching of SMC and matrix biomechanics during growth and remodeling. The work contributes to a better understanding of vascular wall biomechanics and adaptation, and may lead to new options for diagnosis and treatment of cardiovascular diseases

Sickle cell anemia patient with sarcoidosis-associated inguinal lymph node and lung infiltration

PubMedID: 16035582Sarcoidosis is a chronic, systemic inflammatory disease of unknown etiology, characterized by noncaseating granulomatous infiltration of any organ. Sickle cell anemia (SCA) is the homozygoid form of sickle cell disease (SCD), which includes a group of genetic disorders characterized by production of an abnormal hemoglobin S (HbS). There are a few case reports with coexistence of sarcoidosis and SCA. We reported a 47-year-old female with SCA and sarcoidosis

Effects of Molecular Rovibrational States and Surface Topologies for Molecule-Surface Interaction: Chemisorption Dynamics of D 2 Collision with Rigid Ni Surfaces

A quasiclassical and micro-canonical molecular dynamic simulation techniques have been applied for D 2 (v, j) + Ni-surface collision systems. Dissociative adsorptions of a D 2 molecule on the rigid low index (100)

Global minima for free Pt

Using molecular dynamics and thermal quenching simulation techniques, and the basin-hopping Monte Carlo algorithm we have studied the global minima and energetics of free PtN clusters in the size range of $N=22{-}56$. The clusters have been described by the Voter and Chen version of an embedded-atom model, which is derived by fitting to experimental data of both the diatomic molecule and bulk platinum simultaneously. A comparison between the two search techniques has been performed and it is found that the basin-hopping algorithm is more efficient than a molecular dynamics minimization approach in the investigation of the global minima. The results show that the global minima of the Pt clusters have structures based on either octahedral, decahedral or icosahedral packing. Some of the icosahedral global minima do not have a central atom. The 54-atom icosahedron without a central atom is found to be more stable than the 55-atom complete icosahedron. The resulting structures have been compared with the previous theoretical calculations