Modeling the sequential switching shunt series regulator

This letter characterizes, in terms of the bandwidth and limit cycle frequency of its constituent subsystems, the sequential switching shunt series regulator -S/sup 4/R, a high-efficiency, low-mass and volume power cell devised to power the next generation of regulated power buses in telecommunication spacecrafts. Transconductance power source modeling is used to obtain linear and nonlinear models. These are used to establish a design control strategy which involves the dynamic response in large load requirements or at the end of the satellite life. Simulations and experimental results are also given to demonstrate the validity of the model.     

Dissipative particle dynamics simulations for fibre suspensions in newtonian and viscoelastic fluids

A versatile model of fibre suspensions in Newtonian and viscoelastic fluids has been developed using dissipative particle dynamics method. The viscoelastic fluid is modelled by linear chains with linear connector spring force (the Oldroyd-B model), which is known to be a reasonable model for the so-called Boger fluid (a dilute suspension of polymer in a highly viscous solvent). The numerical results are in excellent agreement with the analytical results of the Oldroyd-B model in simple shear flow. An effective meso-scale model of fibre in DPD is proposed and then incorporated with simple Newtonian fluid and our Boger fluid to enable entirely study rheological properties of fibre suspensions in both Newtonian and viscoelastic solvents. The numerical results are well compared with available experimental data and other numerical models.     

Iterative Regularization via Dual Diagonal Descent

In the context of linear inverse problems, we propose and study a general iterative regularization method allowing to consider large classes of data-fit terms and regularizers. The algorithm we propose is based on a primal-dual diagonal descent method. Our analysis establishes convergence as well as stability results. Theoretical findings are complemented with numerical experiments showing state-of-the-art performances.     

Real time estimation of photovoltaic modules characteristics and its application to maximum power point operation

In this paper, an approximate curve fitting method for photovoltaic modules is presented. The operation is based on solving a simple solar cell electrical model by a microcontroller in real time. Only four voltage and current coordinates are needed to obtain the solar module parameters and set its operation at maximum power in any conditions of illumination and temperature. Despite its simplicity, this method is suitable for low cost real time applications, as control loop reference generator in photovoltaic maximum power point circuits. The theory that supports the estimator together with simulations and experimental results are presented.     

Modulated optical properties in Ag and Au films

Modulation spectroscopy is a recent technique for investigating the optical properties of solids. Some results concerning piezo-reflectance, thermo-reflectance, electro-reflectance and electro-transmittance of Ag and Au films are given.     

Application of 13C nmr spectroscopy to the elucidation of the electrochemical oxidation mechanism of the l-ascorbic and d-araboascorbic acids

The previously proposed electrochemical oxidation mechanism of the l-ascorbic and d-araboascorbic acids in basic medium must be rejected because of the variation in the carbon chemical shifts and coupling constants with the pH, which shows that the supposed rupture of the furanose rings at pH ～ 9 does not occur. Electrolysis in basic medium yields the same products as those obtained when the pH of the products of the electrolysis in acid medium are raised to pH ～ 11. This suggests that the oxidation mechanisms in acid and basic media are similar. The assigned carbon chemical shifts of the oxidation products in acid medium $\text{3}$ (or $\text{4}$) and in basic medium $\text{5}$ (or $\text{6}$) and $\text{7}$ (or $\text{8}$) are reported.     

The benchmark framework and exploratory study to investigate the feasibility of 360-degree video-based virtual reality to induce a full body illusion

Virtual Reality - The feeling of ownership of a virtual body has been a topic of interest in recent years. In order to observe the mechanisms involved in the perception of the body illusion and its...     

Design of clay/cement mixtures for extruded building products

In this work, ternary mixes of sand, cement and kaolin are studied in order to design extruded building products with reduced environmental impact. Firstly, the amount of water required to reach the extrusion rheological criterion and the immersed mechanical strength are studied. Results lead to a compressive strength prediction tool (derived from Feret model) which provides the compressive strength of a given ternary mix. Then, the dimensional and immersion stabilities of ternary mixes are studied. It shows that for mixes containing more kaolin volume than cement volume, mechanical strength is largely influenced by the saturation state. Finally, collected data show that cement stabilized clay blocks and high content cement substitution concrete can be designed with clay/cement mixes.     

Rheological modeling of carbon nanotube suspensions with rod–rod interactions

To explain the shear‐thinning behavior of untreated carbon nanotube (CNT) suspensions in a Newtonian matrix, a new set of rheological equations is developed. The CNTs are modeled as rigid rods dispersed in a Newtonian matrix and the evolution of the system is controlled by hydrodynamic and rod–rod interactions. The particle–particle interactions is modeled by a nonlinear lubrication force, function of the relative velocity at the contact point, and weighted by the contact probability. The stress tensor is calculated from the known fourth‐order orientation tensor and a new fourth‐order interaction tensor. The Fokker‐Planck equation is numerically solved for steady simple shear flows using a finite volume method. The model predictions show a good agreement with the steady shear data of CNTs dispersed in a Newtonian epoxy matrix as well as for suspensions of glass fibers in polybutene,¹ demonstrating its ability to describe the behavior of micro‐ and nanoscale particle suspensions. © 2013 American Institute of Chemical Engineers AIChE J, 60: 1476–1487, 2014     

起直流稳压（流）电子负载核心作用的功率MOSFET

设计人员都用直流电子负载来测试电源．如太阳能阵列或电池．但商用直流电子负载很昂贵。你只要将功率MOSFET在其线性区内使用，就可制作出自己的直流电子负载(图1)。该负载采用两个简单的反馈回路。MOSFET用作一个稳流模式下的电流源或稳压模式下的电压源。设计师在描述电压源的特性时都使用稳流模式，因为在稳流模式下，电源必须提供电子负载中设定的电流值。