Towards SoC Validation Through Prototyping: A Systematic Approach Based on Reconfigurable Platform

Hardware/software covalidation is becoming one of the most critical issues in current System-on-Chip (SoC) design. Nowadays, covalidation is usually performed by cosimulation which is slow and lacks accuracy. The other alternative is to build a hardware prototype specific to the application. However, this alternative is expensive in terms of time, man-power, and cost. As SoCs increase in complexity, validation becomes more and more difficult, time consuming and error prone. Thus, a new approach for covalidation is inescapable. In this paper, we present a novel efficient prototyping approach for complex SoC covalidation. The proposed approach enables systematic prototyping of embedded applications on a reconfigurable platform. The process starts from the RT level model of the application. The application and the reconfigurable platform have to be adapted to obtain the prototype. We decompose the prototyping process into four steps, in order to match the application and the platform. Besides, we propose adapted solutions to deal with constraints typically encountered in existing reconfigurable platforms. The main advantages of this method are: fast and accurate validation, systematic prototyping flow, and large application field. Prototyping of a subset of VDSL using the ARM Integrator platform illustrates the effectiveness of our approach.     

Electrochemical stability of core–shell structure electrode for high voltage cycling as positive electrode for lithium ion batteries

The core–shell type cathode material Li[(Ni_0.8Co_0.1Mn_0.1)_0.8(Ni_0.5Mn_0.5)_0.2]O₂ (CS) for Li-ion battery was synthesized via co-precipitation method. The electrochemical and thermal properties of the core–shell structured Li[(Ni_0.8Co_0.1Mn_0.1)_0.8(Ni_0.5Mn_0.5)_0.2]O₂ were compared with those of the average composition of core–shell Li[Ni_0.74Co_0.08Mn_0.18]O₂ (ACCS) and the mixture of the core Li[Ni_0.8Co_0.1Mn_0.1]O₂ and the shell Li[Ni_0.5Mn_0.5]O₂ material (MCS). The CS shows the enhanced electrochemical properties in a high voltage range (4.5 V and 4.6 V) as well as the typical cut-off voltage range (4.3 V). The capacity retentions of CS, core, and ACCS material were 94.2% (176.9 mAh g⁻¹), 86.6% (172 mAh g⁻¹), and 88.4% (169.3 mAh g⁻¹) after 120 cycles, respectively.     

Design modeling of lithium-ion battery performance

A computer design modeling technique has been developed for lithium-ion batteries to assist in setting goals for cell components, assessing materials requirements, and evaluating thermal management strategies. In this study, the input data for the model included design criteria from Quallion, LLC for Gen-2 18650 cells, which were used to test the accuracy of the dimensional modeling. Performance measurements on these cells were done at the electrochemical analysis and diagnostics laboratory (EADL) at Argonne National Laboratory. The impedance and capacity related criteria were calculated from the EADL measurements. Five batteries were designed for which the number of windings around the cell core was increased for each succeeding battery to study the effect of this variable upon the dimensions, weight, and performance of the batteries. The lumped-parameter battery model values were calculated for these batteries from the laboratory results, with adjustments for the current collection resistance calculated for the individual batteries.     

Performances of the Barra–Costantini passive heating system under Algerian climate conditions

The present work studies the Barra–Costantini passive solar heating system, with particular emphasis on the aspect of economics. The system which is studied is developed by Barra and Constantini. This system seems to be well adapted to the climatic and economic conditions in Algeria. In the first part of this work, an ideal model representing the thermal behavior of a room provided with the heating device is elaborated. The results of this model are compared with the results of an experimental study carried out on an Italian site. Initially, the model was used to determine the temperature variation for the different elements of a room with the Barra–Costantini (B-C) system. The model is then used for conditions corresponding to several Algerian sites. This study makes it possible to quantify the energy savings obtained by the addition of the B-C system to a traditional gas heating system. The introduction of a ratio between the cost of energy and the cost of equipment makes it possible to conclude that only the intervention of the authorities can make the passive solar system economically viable.     

Effect of depithing on pulps from egyptian bagasse

Egyptian bagasse was pulped by the prehydrolysis-soda process followed by multi-state bleaching. Raising the concentration of sodium hydroxide used in the second step of bleaching improved the chemical characteristics of the pulp. Depithing had to be applied to improve the degree of pulping and to reduce the ash content. The minimum ash content (0.07%) was arrived at either by carrying out depithing before prehydrolysis to the extent of 2%, or after prehydrolysis to the extent of 10%. Depithing before prehydrolysis was superior as it resulted in a better yield, higher alpha cellulose, and higher degree of whiteness.     

Conduction degradation by fretting corrosion phenomena for contact samples made of high-copper alloys

The main cause of electrical contact resistance degradation by corrosion is the vibration of contact interfaces. The purpose of this paper is to analyse the change of contact resistance by means of a vibration test for uncoated sphere/plane contact made of new high-copper alloys.The influence of electrical and mechanical properties of materials, and mainly hardness, on contact resistance has been studied in this work. During the fretting test, a contact point was submitted to 16,000 vibration cycles under fretting amplitude of 50 μm and 1 Hz frequency. The sphere part was fixed, while the plane part was submitted to relative motion. At the end of the test, the fretted surfaces and the wear debris were analyzed by scanning electron microscope and energy dispersive X-ray spectroscopy to evaluate damage, oxidation and elemental composition present in the wear surfaces. In addition, the measurement of the wear track profile using a 3D surface scanning system was introduced. Increases in contact resistance and contact temperature were examined during the fretting test.The results showed that the contact resistance for the harder alloy was higher than that obtained for the other materials. In addition, topographic measurements showed that the small wear track corresponds to the harder material.     

Modeling of coupled mass and heat transfer through venting membranes for automotive applications

Experimental and theoretical approaches based on a mathematical model, have been developed to study the evolution of environmental parameters (temperature, total pressure, relative humidity, and water vapor partial pressure) inside a housing of an electronic device with a window containing a macroporous membrane. The model was based on the coupling of mass and heat transfer taking into account the effects of polarization of concentration in boundary layers. Membranes have been characterized by mercury porosimetry, liquid entry pressure measurements, scanning electron microscopy, and gas permeation. Once the model was experimentally validated, it was applied to investigate the influence of membranes on heat and mass transfer and to study the impact of the boundary layers on the global mass transport. The results demonstrated the importance of the membrane choice and dimensions to get the best temperature regulation and avoid water condensation inside an automotive electronic control unit (ECU). © 2008 American Institute of Chemical Engineers AIChE J, 2009     

Redox shuttles for safer lithium-ion batteries

Overcharge protection is not only critical for preventing the thermal runaway of lithium-ion batteries during operation, but also important for automatic capacity balancing during battery manufacturing and repair. A redox shuttle is an electrolyte additive that can be used as intrinsic overcharge protection mechanism to enhance the safety characteristics of lithium-ion batteries. The advances on stable redox shuttles are briefly reviewed. Fundamental studies for designing stable redox shuttles are also discussed.