Energy efficiency for edge multimedia elastic applications

With the rise of edge computing paradigms, multimedia applications will have to tackle unprecedented management issues, pursuing an optimal balance between performance, Quality of Service (QoS), and power consumption. In this paper, we investigate a novel paradigm to deploy multimedia elastic applications at the edge in a very energy-efficient manner. Our approach is based on pre-provisioning virtual resources that remain “frozen” until the application scales out. Frozen resources are treated in a special way by the infrastructure, leveraging aggressive power-saving mechanisms that keep negligible their impact on energy consumption and performance. We report extensive measurements on QoS and power consumption that we carried out in a real testbed, which is the first working implementation of the proposed paradigm. Our work shows how resource utilization and performance can be increased by leveraging SDN technologies and conscious setting of cloud parameters. We investigate the trade-off between performance and power consumption (i.e., energy efficiency), in relation to different consolidation strategies. Finally, we measure power consumption and estimate energy saving for an elastic video transcoding application deployed at the network edge.

     

Development of polymer blend morphology during compounding in a twin-screw extruder. Part III: Experimental procedure and preliminary results

Currently, selection of screw configurations as well as the operating conditions for compounding polymer blends with desired morphology in a co-rotating twinscrew extruder is an art based on experience. In this paper a quenching section of a twin-screw extruder is described. The section may replace any segment of the extruder barrel. It allows, on the one hand, a regular operation of the machine, and on the other, a rapid quenching and removal of blend specimens for morphology analysis from any place along the extruder barrel and at any time of the blending. The experimental observation of development during compounding of polymer blends enables verification and improvement of the theoretical model, aimed at predicting and controlling the size and polydispersity of the minor phase. Development of the predictive model for blend morphology will provide a valuable guide to the polymer processing industry. The preliminary data were collected using polystyrene/high density polyethylene (PS/HDPE) blends at low concentration of the dispersed phase, 5 wt% of either PS or HDPE. It was observed that the viscosity ratio, blend composition, screw configuration, temperature, throughput, and screw speed significantly influence the blend morphology.     

Cutting the energy bills of Internet Service Providers and telecoms through power management: An impact analysis

The energy consumption of the Information and Communication Technology (ICT) sector has been increasing recently; this sector is estimated to account for 2% of the total energy consumption. An even more aggressively increasing trend is the volume of Internet traffic and the number of connected devices. Thus, reducing the energy needs of the Internet is recognised as one of the main challenges that the ICT sector will have to face in the near future to reduce its overall energy footprint. Introducing energy-efficient techniques, both at the device level and the network level, is required.The main goal of this work is to quantitatively evaluate the potential energy savings from applying energy-efficient techniques, while examining the trade-off between network performance and the achieved energy savings.We introduce a categorisation of the energy-aware design space, focusing on the existing techniques in the device data plane, and contribute an analytical framework to represent the impact of energy-aware technologies and solutions for network devices. Our energy profile model represents the diverse energy-aware states of the network devices and is applied over two reference scenarios, one of a large-scale Telco (Telecom Italia) and one of a medium size Internet Service Provider (GRNET), to evaluate the impact of each energy-aware technology and the energy savings potential at the Home, Access, Metro/Transport and Core parts of each network.The results show the estimates of energy savings exceed 60% in many cases, while maintaining the same quality of service as in the energy-agnostic case.     

X-Ray and Infrared Investigation of the Supramolecular Structure of PVC

Two types of crystalline morphology seem to be present in commercial PVC powder, both related to syndiotactic sequences in Natta orthorhombic cell: (1) ribbon-like crystats formed during the second stage of the mass-process and in suspension or by annealing PVC samples above T_g. (2) high melting fringed-micelles are the main crystalline feature of emulsion type powder and of low-conversion mass PVC. A second less ordered phase, which does not fit the Natta cell is found also in emulsion powder and in highly strained samples (like fibres). Ribbon-like crystals and fringed-micelles influence the i.r. absorption at 604 and 638 cm^?1 respectively. 685cm^?1 might be related to the low-order phase, the X-ray spacing of which is 3.8--4.0 Å along the chain.     

Processing of poly(amide imides) as matrices for high-performance composites

Poly(amide imide) (PAI) has proven to be an excellent engineering thermoplastic. Injection and compression molding processes are currently used to produce poly(amide imide) parts when superior toughness, solvent resistance, and high-temperature heat performance are required. The objective of this work was to determine the essential features necessary to use these systems as matrices for carbon-fiber-reinforced composites. The principal steps utilized were: impregnation of the carbon fibers with a PAI solution, drying the solvent from the individual plies, stacking the plies for final consolidation, and a postcure. A processing cycle was developed applicable to resins with different solvent concentration and molecular weight, giving special attention to the solvent evaporation step. A model capable of predicting the rate of evaporation as a function of temperature was developed using the principle of time–temperature superposition. A viscosity model similar to that for a curing thermoset was developed by combining Arrhenius expressions for the temperature and concentration effects. Collectively, this work then provided insight for matrix requirements in the formulation of PAI composites by solvent impregnation.