Building Quality-of-Service Monitoring Systems for Traffic Engineering and Service Management

Deployment of quality-of-service (QoS) based value-added services in IP networks necessitates the use of traffic engineering. Traffic engineering allows service providers to use the network resources efficiently, according to the different quality levels associated with the range of services they offer. Traffic engineering relies typically on monitoring data for both offline proactive and dynamic reactive approaches. Monitoring data may be used for network provisioning, dynamic resource allocation, route management, and in-service performance verification for value-added IP services. A monitoring system should scale with the network size, the network speed, and the number of customers subscribed to use value-added IP services. This paper investigates the requirements of scalable monitoring system architectures, proposes principles for designing such systems and validates these principles through the design and implementation of a scalable monitoring system for traffic engineering and QoS delivery in IP Differentiated Services networks. Methods for assessing the relative merits of such monitoring systems are proposed. Experimental assessment results prove the scalability, accuracy, and also demonstrate the benefits of the proposed monitoring system.     

Partial oxidation of methane and the effect of sulfur on catalytic activity and selectivity

Partial oxidation of methane into syngas was conducted over fresh and sulfided catalysts at a temperature range of 450–750 °C. The temperature dependence of conversion, H₂/CO ratio, and the CO₂ concentration were measured for both fresh and sulfided catalysts. Regardless of metal type, metal loading, support type, and the methods of preparation it appears that all the fresh catalysts were very active and conversions of higher than 70% with H₂/CO ratio of about 2 were observed at 750 °C. Pulse sulfidation appears to be reversible for some of the catalysts but not for all. Under pulse sulfidation conditions, the Rh(0.5%)/Al₂O₃ and NiMg₂O_x-1100 °C (solid solution) catalysts were fully regenerated after reduction with hydrogen. Rh catalyst showed the best overall activity, less carbon deposition, both fresh and when it was exposed to pulses of H₂S. Sulfidation under steady-state conditions, flowing H₂S/Ar mixture over the catalysts, significantly reduce catalyst activity. The catalysts were characterized before and after reaction with H₂S using temperature-programmed oxidation (TPO) and reduction (TPR), X-ray diffraction, and XPS.     

Effects of nozzle arrangement angle on the performance of partially admitted turbines

Journal of Mechanical Science and Technology - This paper presents the experimental and numerical evaluations of the effects of a supersonic Nozzle arrangement angle (NAA) on the performance of an...     

Bio-oil production and upgrading research: A review

Biomass can be utilized to produce bio-oil, a promising alternative energy source for the limited crude oil. There are mainly two processes involved in the conversion of biomass to bio-oil: flash pyrolysis and hydrothermal liquefaction. The cost of bio-oil production from biomass is relatively high based on current technologies, and the main challenges are the low yield and poor bio-oil quality. Considerable research efforts have been made to improve the bio-oil production from biomass. Scientific and technical developments towards improving bio-oil yield and quality to date are reviewed, with an emphasis on bio-oil upgrading research. Furthermore, the article covers some major issues that associated with bio-oil from biomass, which includes bio-oil basics (e.g., characteristics, chemistry), application, environmental and economic assessment. It also points out barriers to achieving improvements in the future.     

Characterization of B site codoped LaFeO_3 nanoparticles prepared via co-precipitation route

LaFe_1-x-yCo_xPd_yO_3 [(x, y) =(0, 0),(0.40, 0),(0.38, 0.05)] nanoparticles were synthesized via a co-precipitation route using ammonium hydroxide, sodium hydroxide and ammonium carbonate as the precipitant and calcination at different temperatures to study the compositional driven structural changes in lanthanum ferrites.Analysis of X-ray diffraction(XRD) patterns confirms the formation of single-phase perovskite structure and existence of orthorhombic Pnma symmetry for calcined powders. Field emission scanning electron microscope(FESEM) observations show that Pd-doped powders yield finer particles along with narrower particle size distribution compared with LaFeO_3 and LaFe_0.6Co_0.4O_3. Moreover,using ammonia as the precipitant leads to a smaller mean particle size of powders compared to NaOH, as well as significant difference in morphology of the particles.Raman analysis reveals that both Co and Pd atoms substitute Fe site in perovskite structure with shifting of phonon modes. Comparing Raman spectra demonstrates the presence of more oxygen vacancies in Pd-doped perovskites. It can be concluded from the results that Pd is successfully incorporated into the perovskite structure by co-precipitation method.     

Interdomain routing through QoS-class planes [Quality-of-Service-Based Routing Algorithms for Heterogeneous Networks]

This article presents an approach to delivering qualitative end-to-end quality of service (QoS) guarantees across the multiprovider Internet. We propose that bilateral agreements between a number of autonomous systems (ASs) result in the establishment of QoS-class planes that potentially extend across the global Internet. The deployment of a QoS-enhanced border gateway protocol (BGP) with different QoS-based route selection policies in each of the planes allows a range of interdomain QoS capabilities to coexist on the same network infrastructure. The article presents simulation results showing the benefits of the approach and discusses aspects of the performance of QoS-enhanced BGP     

Effect of sintering parameters (time and temperature) upon the fabrication process of organic binder-based metallic hollow sphere

Metallic hollow spheres (MHSs) are developed to be used in structural applications in syntactic and metal foams. These foams are lightweight and energy-absorbing structures which also can be used for acoustic insulation. In this study, the fabrication process of MHSs with optimum mechanical properties has been investigated. To achieve this goal, polystyrene spheres were coated with iron powder and an organic binder. During the multi-stage heat treatment, the green spheres were sintered into MHSs. Sintering was done at various temperatures (1125, 1150, 1175 and 1200°C) at different durations (3:30, 4:30 and 5:30?h). The influence of the different sintering durations and temperatures on mechanical features, microstructure and density was studied as well. The obtained results indicate that samples that were sintered at the temperature of 1175°C for 4:30?h resulted in superior mechanical and physical properties.     

Effect of geometry of end of the fibre transport channel with slotted exit on rotor spun yarn quality

Geometry of end of the fibre transport channel (EFTC) at the entry to the rotor housing of rotor spinning system has an important effect on yarn properties. In this paper, effect of design of fibre exit edge (FEE) of the transport channel on yarn properties in a slotted model similar to R20 of Rieter was studied. Nine designs of FEE were examined for fibre path and the best one was selected for yarn production. Dimension and positioning of FEE were varied and yarn tensile properties, evenness, imperfections and extent were tested. It was concluded from the test results that the new design improves most of the yarn properties and is superior to the original design.