Chemical sensor based on a novel capacitive microwave flexible transducer with polymer nanocomposite-carbon nanotube sensitive film

Microsystem Technologies - This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and...     

A novel multi-model neuro-fuzzy-based MPPT for three-phase grid-connected photovoltaic system

This paper presents a novel methodology for Maximum Power Point Tracking (MPPT) of a grid-connected 20 kW photovoltaic (PV) system using neuro-fuzzy network. The proposed method predicts the reference PV voltage guarantying optimal power transfer between the PV generator and the main utility grid. The neuro-fuzzy network is composed of a fuzzy rule-based classifier and three multi-layered feed forwarded Artificial Neural Networks (ANN). Inputs of the network (irradiance and temperature) are classified before they are fed into the appropriated ANN for either training or estimation process while the output is the reference voltage. The main advantage of the proposed methodology, comparing to a conventional single neural network-based approach, is the distinct generalization ability regarding to the nonlinear and dynamic behavior of a PV generator. In fact, the neuro-fuzzy network is a neural network based multi-model machine learning that defines a set of local models emulating the complex and nonlinear behavior of a PV generator under a wide range of operating conditions. Simulation results under several rapid irradiance variations proved that the proposed MPPT method fulfilled the highest efficiency comparing to a conventional single neural network and the Perturb and Observe (P&O) algorithm dispositive.     

Co-immobilization of chitosan and dermatan sulfate from Raja montagui skin on polyethylene terephthalate surfaces: Characterization and antibiofilm activity

In this work, polyethylene terephthalate (PET) was chemically modified by covalent co-immobilization of two separate layers of bioactive polymers composed of chitosan and a new dermatan sulfate isolated from Raja montagui skin. The new materials obtained were characterized by determination of carboxyl groups, ATR-FTIR spectroscopy, drop water contact angle, SEM, and TGA measurements. The different immobilizations modified the surface characteristics; especially when the first layer was dermatan sulfate (PET–DS–Chito) which presented the best surface wettability (71?±?3°). It also reduced the ability of Staphylococcus epidermidis to form biofilm on PET surfaces which could decrease the virulence of vascular prosthesis infections.     

Evaluating Experimental Measurements of the IEEE 802.11p Communication Using ARADA LocoMate OBU Device Compared to the Theoretical Simulation Results

Wireless Personal Communications - Research interest has been focused on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication systems, known as V2X technologies, namely in...     

Enhancement of micro-grid performance during islanding mode using storage batteries and new fuzzy logic pitch angle controller

Power system deregulation, shortage of transmission capacities and needing to reduce green house gas have led to increase interesting in distributed generations (DGs) especially renewable sources. This study developed a complete model able to analysis and simulates in details the transient dynamic performance of the Micro-Grid (MG) during and subsequent islanding process. Wind speed fluctuations cause high fluctuations in output power of wind turbine which lead to fluctuations of frequency and voltages of the MG during the islanding mode. In this paper a new fuzzy logic pitch angle controller is proposed to smooth the output power of wind turbine to reduce MG frequency and voltage fluctuations during the islanding mode. The proposed fuzzy logic pitch controller is compared with the conventional PI pitch angle controller which usually used for wind turbine power control. Results proved the effectiveness of the proposed fuzzy controller in improvement of the MG performance. Also, this paper proposed using storage batteries technique to reduce the frequency deviation and fluctuations originated from wind power solar power fluctuations. Results indicate that the storage batteries technique is superior than fuzzy logic pitch controller in reducing frequency deviation, but with more expensive than the fuzzy controller. All models and controllers are built using Matlab® Simulink® environment.     

Synthesis and in vitro evaluation of alpha-GalCer epimers

alpha-GalCer (also known as KRN7000) is an immunomodulatory glycolipid that is known to potently activate invariant natural killer T (NKT) cells upon CD1d-mediated stimulation. Because Th1 and Th2 cytokines, which are released after alpha-GalCer presentation, antagonize each other's effects, alpha-GalCer analogues that induce a biased Th1/Th2 response are highly awaited. In this context, we report the synthesis and in vitro evaluation of alpha-Gal-D-xylo-Cer and two alpha-Gal-L-lyxo-Cer analogues, one with the natural acyl chain, the other with a truncated chain.     

Performance Model of a WIMAX 2.0 All-IP 4G System

4G is promising a wireless broadband with data rates up to 1Gbps. The two candidate technologies for 4G are the Advanced Long Term Evolution (Advanced LTE) which is based on the 3GPP standards and the WiMAX 2.0 based on the IEEE 802.16 family of standards. The common feature of both technologies is that they will provide All-IP connectivity with flexible bit rates and quality of service guarantees for multiple classes of services including voice, mainly using voice over IP, data and video services. Most of the performance studies of 4G technologies use highly complex and sophisticated simulations due to the multiple complexity factors in investigating 4G technologies such as All-IP flexible bit rates, adaptive coding and modulation as well as the multi-services provided. These factors usually make any modelling attempt very difficult. This paper presents a numerical/analytical model for a 4G WiMAX cell based on a multi-dimensional Continuous-Time Markov Chain (CTMC) model. Performance measures were derived for the key performance indicators such as throughput and average bit rate per cell and per service class. By assuming minimum acceptable bit rates for certain quality of service guarantees, we derived measures for blocking probabilities. The model has been formulated and solved using MOSEL-2 (Modelling Specification and Evaluation Language) which captures the key features of a 4G system that affect services at session/call level. The resuls obtained from the model using sample parameters show that, the model can provide very useful insight to system behavior and can give good first indication to the performance of such a complex system.     

A physically based diode model for circuit simulation

A physically based power PiN diode model is presented. Eigen value internal approximation method is used to solve the ambipolar diffusion equation. This model is implemented in SIMPLORER circuit simulator using VHDL‐AMS language. The proposed model can be used in both circuit simulators and the optimization of a given power PiN diode. Good agreement is obtained by comparing the results of the suggested model with experimental data. Copyright © 2013 John Wiley & Sons, Ltd.