A Game Theoretical Approach for Improving the Operational Efficiencies of Less-than-truckload Carriers Through Load Exchanges

Less-than-truckload (LTL) transportation offers fast, flexible and relatively low-cost transportation services to shippers. In order to cope with the effects of economic recessions, the LTL industry implemented ideas such as reducing excess capacity and increasing revenues through better yield management. In this paper, we extend these initiatives beyond the reach of individual carriers and propose a collaborative framework that facilitates load exchanges to reduce the operational costs. Even though collective solutions are proven to provide benefits to the participants by reducing the inefficiencies using a system-wide perspective, such solutions are often not attainable in real-life as the negotiating parties are seeking to maximize their individual profits rather than the overall profit and also they are unwilling to share confidential information. Therefore, a mechanism that enables collaboration among the carriers should account for the rationality of the individual participants and should require minimal information transfer between participants. Having this in mind, we propose a mechanism that facilities collaboration through a series of load exchange iterations and identifies an equilibrium among selfish carriers with limited information transfer among the participants. Our time-efficient mechanism can handle large instances with thousands of loads as well as provide significant benefits over the non-collaborative management of LTL networks.

     

On Saint-Venant’s problem for anisotropic, inhomogeneous, cylindrical Cosserat elastic shells

We investigate the static deformation of cylindrical elastic shells, using the theory of Cosserat surfaces. We consider anisotropic and inhomogeneous cylindrical shells with arbitrary (open or closed) cross-section. The constitutive coefficients are assumed to be independent of the axial coordinate. In the context of linearized theory, we determine a solution of the relaxed Saint-Venant’s problem. Finally, we apply the general results in the special cases of circular cylindrical shells and of Cosserat plates made from an orthotropic material.     

Randomly Distributed Vacancies Influence on Magnetic Properties of the Bilayer Thin Film

In this paper we are investigating the magnetic behavior of the double-layer thin film in the extended Heisenberg model, with long-range dipolar interaction, taking into account the influence of the randomly distributed vacancies on the magnetic properties of the system. We are studying the physical quantities of interest (magnetization, magnetic susceptibility and specific heat) via Monte Carlo technique, by applying the standard Metropolis algorithm. In this context, we investigate the critical temperature variation for different vacancies concentration levels, taking into account the uniform and the superficial distribution of the defects, respectively.      

Influence of Fiber Orientation and Fillers on Low Velocity Impact Response of the Fabric Reinforced Epoxy Composites

The low velocity impact response of the epoxy composite materials, which were reinforced with various hybrid contents, such as plain pure or hybrid fabrics (carbon, aramid and glass fibers and copper wires) and filler mixtures into the epoxy matrix (aramid powder, potatoes starch, barium ferrite and carbon black) was investigated using a drop weight impact machine. The aim of this study was to characterize and assess the effects of fiber orientation at various angles and filler mixtures into epoxy matrix on the impact response. All the tests were carried out at constant impact energy, namely 90.629 J. Results indicated that the fiber orientation at various angles has a positive effect on impact response, mainly in the case of aramid fabric reinforced composites. In terms of influence of fillers addition into matrix, it was obtained an improvement on the impact response of hybrid fabric reinforced composite as compared to the pure fabric reinforced composites.

     

Deformation analysis of functionally graded beams by the direct approach

In this paper we employ the direct approach to the theory of rods and beams, which is based on the deformable curve model with a triad of rotating directors attached to each point. We show that this model (also called directed curve) is an efficient approach for analyzing the deformation of elastic beams with a complex material structure. Thus, we consider non-homogeneous, composite and functionally graded beams made of isotropic or orthotropic materials and we determine the effective stiffness properties in terms of the three-dimensional elasticity constants. We present general analytical expressions of the effective stiffness coefficients, valid for beams of arbitrary cross-section shape. Finally, we apply this method for FGM beams made of metal foams and compare our analytical results with the numerical results obtained by a finite element analysis.     

Thermoelastic Deformations of Cylindrical Multi-Layered Shells Using a Direct Approach

In this article we study the deformation of thermo-elastic multi-layered shells, using a Cosserat model. By this direct approach, the shell-like bodies are modeled as deformable surfaces with a triad of rigidly rotating directors assigned to every point. The thermal effects are described with the help of two independent temperature fields. Concerning cylindrical orthotropic layered shells, we establish a general solution procedure for a class of thermal stresses problems. These analytical solutions are compared in some special cases with the corresponding three-dimensional solutions and thus, the thermo-elastic coupling coefficients for shells are identified in terms of the material/geometrical parameters of the layers. Finally, we present a comparison between our theoretical results and the numerical solutions obtained by a finite element analysis of a 3-layered cylindrical shell.     

Properties of Indium Oxide Semiconducting Sensors Deposited by Different Techniques

Semiconducting In₂O₃ gas sensors have been fabricated by two different deposition techniques, i.e., spin-coating and screen-printing. In both cases the same starting material – sol-gel-prepared cubic In₂O₃ – was used for the deposition in order to ensure a better comparability of the different sensing layers. The morphology of the layers has been characterized using scanning electron microscopy (SEM) technique. The layers deposited by different methods show similar grain size and porosity. Furthermore, Dc electrical tests have been performed to analyze the sensing properties of the different gas sensors. Reducing gases (CO and propanal) as well as oxidizing gases (NO₂ and ozone) were used as test gases in the background of dry and humidified synthetic air. All measurements were performed at several temperatures. It was found that the spin-coated and screen-printed layers show different sensing properties, i.e., screen-printed sensors showed higher sensor signals than spin-coated sensors for CO, propanal, and NO₂. The most striking differences appeared in the detection of ozone. In this case, spin-coated sensors showed a higher performance than screen-printed sensors. Higher ozone concentrations led to saturation effects for the latter.     

Aspects of hydatidosis in the adult population in Banat

An epidemiological study was performed on a lot of 505 adult subjects (over 20 years old) diagnosed with E.granulosus hydatidosis and operated in surgery units in hospitals from such towns as Timi?oara, Arad and Re?ita (1985-1992). The incidence of hydatid infection was almost uniformly distributed by sexes, being a little higher in rural areas (52.0%); the highest number of cases was reported in Timi? County (63.6%), followed by Cara?-Severin County (21.2%). Hydatidosis was most frequently found in liver (67.5%) and lungs (23.7%) and more rarely in kidneys (0.4%), brain (0.2%), pancreas (0.2%), ovary (0.2%). Secondary hydatidosis was reported on 12.7% of cases and multiple cyst forms in 12.7% of cases. The distribution of cases by age group was relatively balanced, a slightly increased incidence being found in the 20-29 years age group (23.2%), about 1/3 of pulmonary localizations being reported in the age group. Post-surgery complications were reported in 13.5% of the total hepatic localizations and in 30% of the pulmonary localizations. The average number of days in hospital was 29.5 days/case. The average morbidity in the adult population in Banat over an eight years time interval was 5.36%ooo, being higher in Timi? county-7.8%ooo where a peak (11%ooo) was reported in 1987.     

On decomposition and integral representation of solutions for affine control systems

A decomposition formula for the trajectories of an affine control system with noncommuting control vector fields is presented.     

Numerical Study on Magnetic Transitions in Double-Layer Spin Lattice Using Anisotropic Heisenberg Model

Monte Carlo simulations have been used to study the magnetic properties of double-layer thin film in Anisotropic Heisenberg Model with different anisotropy and direct exchange parameters, applying Metropolis algorithm. We investigate the antiferromagnetic ordering of the basal layer spins’ influence on the magnetic behavior of the superior layer. The magnetization, out-of-plane and in-plane magnetic susceptibilities, staggered magnetization and also the specific heat behaviors according to temperature are investigated in order to find out the potential magnetic ordered phases and the critical temperatures, for different parameter settings. Taking into account the balance between direct exchange and anisotropy interaction parameters we detect five different magnetic ordering states. These are: ferromagnetism, short-range ferromagnetism, antiferromagnetism, in-plane ordering and paramagnetism, which are characterized by specific properties; and we point also out some different magnetic phase transitions that can appear in the system.