Integrated Mobility and QoS Control in Cellular Wireless ATM Networks

This paper presents a traversed pathtracking-based technique for integrated mobility andquality-of-service (QoS) management of connections incellular wireless ATM networks. Simulation andanalytical results for probabilities of connectionBlocking, Dropping, and Unsuccessful Connections aredetermined. A distributed operating system-basedarchitecture for implementation of integrated mobilityand QoS control is then proposed. The objective is totreat mobility as a network impairment triggeredactivity which is to be handled via QoS management.Depending on the speed of the mobile unit and thecategory of service being used, the QoS of a connectionmay or may not vary continuously during a session. Theresults presented here consider coexistence of constantbit-rate and nonreal-time variable bitrate ATM connections over a single session.     

Design, manufacture and evaluation of a new and simple mechanism for transmission of power between intersecting shafts up to 135 degrees (Persian Joint)

This paper introduces a new mechanism which is designed for the transmission of power between two intersecting shafts. The mechanism consists of one drive shaft and one driven shaft, six guide arms, and three connecting arms. The intersecting angle between the input shaft and the output shaft can be varied up to 135° while the velocity ratio between the two shafts remains constant. The research also includes a kinematic analysis and a simulation using Visual NASTRAN, Autodesk Inventor Dynamic and COSMOS Motion. The softwares showed that this mechanism can transmit constant velocity ratios at all angles between two shafts. By comparing the graphs of analytical analysis and simulation analysis, validity of equations was proved. Finally, by fabrication and evaluation of the mechanism it was shown that this mechanism can transmit constant velocity practically.     

Predicting the spontaneous termination of atrial fibrillation based on poincare section in the electrocardiogram phase space

Atrial fibrillation (AF) is a commonly encountered cardiac arrhythmia. Predicting the conditions under which AF terminates spontaneously is an important task that would bring great benefit to both patients and clinicians. In this study, a new method was proposed to predict spontaneous AF termination by employing the points of section (POS) coordinates along a Poincare section in the electrocardiogram (ECG) phase space. The AF Termination Database provided by PhysioNet for the Computers in Cardiology Challenge 2004 was applied in the present study. It includes one training dataset and two testing datasets, A and B. The present investigation was initiated by producing a two-dimensional reconstructed phase space (RPS) of the ECG. Then, a Poincare line was drawn in a direction that included the maximum point distribution in the RPS and also passed through the origin of the RPS coordinate system. Afterward, the coordinates of the RPS trajectory intersections with this Poincare line were extracted to capture the local behavior related to the arrhythmia under investigation. The POS corresponding to atrial activity were selected with regard to the fact that similar ECG morphologies such as P waves, which are corresponding to atrial activity, distribute in a specific region of the RPS. Thirteen features were extracted from the selected intersection points to quantify their distributions. To select the best feature subset, a genetic algorithm (GA), in combination with a support vector machine (SVM), was applied to the training dataset. Based on the selected features and trained SVM, the performance of the proposed method was evaluated using the testing datasets. The results showed that 86.67% of dataset A and 80% of dataset B were correctly classified. This classification accuracy is in the same range as or higher than that of recent studies in this area. These results show that the proposed method, in which no complicated QRST cancelation algorithm was used, has the potential to predict AF termination.     

Features of the time evolution of localized quantum states in graphene

In the Heisenberg representation, the phenomena of the interference of quantum states of the conduction and valence bands of graphene, arising for localized electron wave packets are analyzed. The interference leads to temporal oscillations in the values of the average physical quantities.     

Cylindrical functionally graded shell model based on the first order shear deformation nonlocal strain gradient elasticity theory

Microsystem Technologies - In this article, a cylindrical functionally graded shell model is developed in the framework of nonlocal strain gradient theory for the first time. For this purpose, the...     

Hot Corrosion Behavior and Microstructural Change of Al-Gradient CoNiCrAlYSi Coatings, Produced by LVPS and Diffusional Processes

Conventional and gradient CoNiCrAlYSi coatings were produced by using low vacuum plasma spray and an additional step of diffusional over aluminizing (pack cementation) techniques on an Inconel-738 substrate. Hot corrosion of these coatings was investigated using Na₂SO₄–20wt%NaVO₃ molten salt at 880?°C for 800?h. Hot corrosion rate was determined by measuring the weight gain of the specimens at regular intervals for a duration of 20?h. X-ray diffraction, field emission scanning electron microscopy and electron probe micro analysis techniques were used to determine the nature of phases, investigation of the thermally grown oxide, examination of the surface attack and determination of the elemental distribution. The gradient coating showed better performance by re-healing alumina scale due to its possession of more β phase as Al reservoir. Results indicated that pack cementation process caused an increase in amount of aluminum-rich β phase and better hot corrosion properties of gradient coatings owing to the Al enrichment in the outer layer and rapid formation of protective oxide on the surface.     

Isogeometric level set topology optimization for elastoplastic plane stress problems

International Journal of Mechanics and Materials in Design - This article aims to utilize IsoGeometric analysis (IGA) and Level set method for topology optimization of elastoplastic plane stress...     

Simple,fast, and accurate parametric modeling of the coupling and external quality factor for microstrip filter design using active learning method

In the realization step of any microstrip filter according to the required electrical characteristics, coupling factors and external quality factor (Q_ext) are related to the physical parameters of the structure using time consuming full wave simulations. This paper presents a simple, fast, and accurate parametric model of the coupling between the coupled square open loop resonators (SOLRs) and Q_ext of these resonators versus physical parameters of the structure and substrate characteristics utilizing active learning method (ALM). In the modeling process the multi-dimensional functions of coupling factor and Q_ext are broken down into their simpler aspects, their behaviors are extracted and then final model will be constructed by combining these simpler aspects. ALM allows the overall model for coupling factor and Q_ext to be developed through the use of small number of initial data. Once the modeling process is completed it provides a fast and accurate prediction of the required physical parameters for a given coupling factor and Q_ext. Using the constructed model for a distinct SOLR, which its accuracy was validated by comparison with the full wave simulation results a filter was designed and fabricated. Good agreement between measured and simulated response confirms the accuracy of the modeling procedure.     

A review of CO2 sorbents for promoting hydrogen production in the sorption-enhanced steam reforming process

Sorption-enhanced-steam-reforming (SESR) is a thermochemical conversion technology that produces a high-purity hydrogen stream by utilizing in-situ removal of CO₂ with a sorbent. In this paper, the advantages and disadvantages of CaO based sorbents, alkali-metal based sorbents (Na₂ZrO₃, Li₂ZrO₃ and Li₄SiO₄), hydrotalcite based sorbents, bifunctional materials and sorbents prepared from wastes are briefly discussed, and the techniques to improve the sorption properties of these CO₂ sorbents are summarized. In the process of hydrogen production by sorption-enhanced-steam-reforming, the selection of suitable high-temperature CO₂ sorbent is the key to produce high purity hydrogen. Furthermore, the hydrogen-production performance of the above-mentioned sorbents in the SESR process is investigated and summarized. Finally, a future perspective and some suggestions regarding these five types of sorbents are put forward.     

Reducing CO2 emission from exhaust gases using molten carbonate fuel cells: a new approach

The aim of this study is to couple molten carbonate fuel cell (MCFC) stack with integrated gasification combined cycle fed by refinery residues, to remove CO₂ from gas turbine exhaust gases that have CO₂ emission rate of 14,200 ton/year. By applying multi-objective optimisation (MOO) using genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. The MOO of the MCFC system regarding two scenarios is performed. The first scenario is minimisation of cost of electricity (COE) and CO₂ emission rate. Objective functions of the second scenario are the same as in the first scenario while CO₂ tax is taken into account. Results show that the second scenario has 29.5% lower average optimal COE and 2.5% lower average emission rate in comparison with the first scenario. A sensitivity analysis is also performed to study the effect of fuel price and CO₂ tax variations on optimal solutions.