Assessment of indoor HONO formation mechanisms based on in situ measurements and modeling

The photolysis of HONO has been found to be the oxidation driver through OH formation in the indoor air measurement campaign SURFin, an extensive campaign carried out in July 2012 in a classroom in Marseille. In this study, the INCA‐Indoor model is used to evaluate different HONO formation mechanisms that have been used previously in indoor air quality models. In order to avoid biases in the results due to the uncertainty in rate constants, those parameters were adjusted to fit one representative day of the SURFin campaign. Then, the mechanisms have been tested with the optimized parameters against other experiments carried out during the SURFin campaign. Based on the observations and these findings, we propose a new mechanism incorporating sorption of NO₂ onto surfaces with possible saturation of these surfaces. This mechanism is able to better reproduce the experimental profiles over a large range of conditions.     

The effect of polyvinyl alcohol addition on the physicochemical properties of ZnO synthesized by ethylene glycol-hydrothermal method

The effect of the addition of very small amount of polyvinyl alcohol (PVA) on the resulting physicochemical properties of ZnO synthesized by ethylene glycol-hydrothermal method was studied. Significant change in particle size distribution and specific surface area can be observed even only 0.02% PVA (w/w) was added into the ethylene glycol (EG) solution, in which the median particle size distribution increased from 5 to 8 nm and at the same time the specific surface area is also increased to nearly 50%. Further addition of PVA resulted in the decrease of the specific surface area due to the formation of agglomeration and aggregation of particles as observed by FESEM study. This study shows that the presence of minute amount of polymer, PVA plays very crucial role in determining the resulting properties of the synthesized ZnO by EG-hydrothermal method.     

Key technologies for IMT-advanced mobile communication systems

WINNER is an ambitious research project aiming at identification, development, and assessment of key technologies for IMTAdvanced mobile communication systems. WINNER has devised an OFDMA-based system concept with excellent system-level performance for flexible deployments in a wide variety of operating conditions. The WINNER system provides a significant step forward from current 3G systems. Key innovations integrated into the system concept include flexible spectrum usage and relaying, adaptive advanced antenna schemes and pilot design, close to optimal link adaptation, hierarchical control signaling, and a highly flexible multiple access scheme. The end-to-end performance assessment results demonstrate that the WINNER concept meets the IMTAdvanced requirements.     

Diffusion of One‐ and Two‐Component Fluids into Polymeric Membranes

The starting point of this paper is a model of the non‐Fickian diffusion of a simple fluid into a polymeric medium that has been introduced in El Afif and Grmela (2002). The model is extended to a mixture consisting of two simple fluids and one polymeric medium. The effects of the polymeric medium on diffusion are included in the formulations through the use of relative momenta playing the role of internal variables. In ternary mixtures, new phenomena arise due to cross‐coupling effects. As a consequence, the single diffusion Deborah number in binary mixtures becomes a 2 × 2 matrix in ternary mixtures. Two specific examples for which experimental data are available are investigated in detail.     

First and second law analysis of a new power and refrigeration thermodynamic cycle using a solar heat source

The first and second laws of thermodynamics were used to analyze a novel thermodynamic cycle proposed by Goswami in 1995 that uses an ammonia–water binary mixture as the working fluid, while producing both power and refrigeration simultaneously. The thermodynamic performance of the cycle was optimized for maximum second law efficiency using a commercially available optimization program. A maximum second law efficiency of 65.8% was obtained at a heat source temperature of 420 K. An exergy analysis was performed to study losses in different components of the cycle. It is seen that the largest contribution to cycle irreversibility comes from the absorber, with the rectifier and solution heat exchanger also contributing significantly. Irreversibility generation in the boiler is high at very low heat source temperatures, but drops at higher temperatures.     

System Performance of Transmit Diversity Methods and a Two Fixed-Beam System in WCDMA

Downlink transmit diversity modes for WCDMA together with a two fixed-beam antenna array system are compared relative to the single antenna sectorized system in a radio network simulator. The transmit diversity methods investigated are: space-time transmit diversity and closed-loop mode I transmit diversity. Frequency selective (COST 259) and flat fading channels are considered and their impact to speech-only and data-only services is evaluated. A third service, which highlights the system performance of the various advanced antennas, is also investigated.The results in this investigation point out that the diversity gain in flat fading channels is substantial. In frequency-selective fading, the benefits of fixed beam systems is encouraging, whereas transmit diversity methods (especially Space-Time Transmit Diversity) is unsatisfactory.     

Investigating the current distribution of parallel-configured quantum point contacts under quantum Hall conditions

Journal of Computational Electronics - Electric-field-controlled charge transport is a crucial concept of modern computers, embodied, namely in field-effect transistors. The metallic gate voltage...     

The effect of the embedded interface dynamics on mass transport in immiscible polymer blends

Mass transport of solvents into immiscible blends may exhibit a non-Fickian behavior due to the deformation of the embedded interface that couples with diffusion. We introduce an interface area covariant tensor N as a structural state variable and derive a set of thermodynamically-consistent PDEs and ODEs transport equations for the bulk and time-dependent boundaries. The proposed model, which is a reformulation of that derived by El Afif (2008) and El Afif et al. (2003), improves both mathematically and numerically the investigation of the diffusion-interface coupling and provides reasonable predictions of the sorption-permeation one dimensional treatment affording good agreement with experimental data. The tensor N englobes, into a single morphological quantity, all information regarding diffusion-induced changes in the size and shape anisotropy of the interface area. Predicted results include concentration, components of N , residual stresses, mass-uptake, and swelling. Scaling leads to three relevant dimensionless parameters: a mixing-interface coupling constant and bulk and boundary diffusion Deborah numbers.