Search results for "nimi"
showing 10 items of 596 documents
Stability of PEI–DNA and DOTAP–DNA complexes: effect of alkaline pH, heparin and serum
2001
Abstract DNA complexes formed with nonviral vectors such as polyethylenimine (PEI) or 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) are widely used in gene therapy. These complexes prevent the interaction of DNA with the fluorescent probes usually employed to quantify DNA. We thus studied the procedures for DNA quantification from DNA complexes as well as their stability in the presence of DNase or mouse, rat and human sera. Release of the DNA from its complexes was accomplished by increasing the pH of the medium (from 7.3 to 13.4) or by adding heparin. The stability against degradation was tested in vitro, by incubating the complexes at 37°C in the presence of DNase I and sera from the …
Experimental investigation on high efficiency real-time control algorithms for IPMSMs
2014
This paper describes an experimental investigation on the power losses variations occurring in an Interior Permanent Magnet Synchronous Motor (IPMSM) with respect to the direct axis current component. Such investigation can be useful to determine a mathematical model accounting for copper, iron and mechanical friction losses, and for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. In particular, a test bench has been set up in order to carry out all measurements and the final power loss identification. The test bed is composed by a IPMSM drive with a field oriented control (FOC) strategy, a power analyzer, a dynamometric brake a…
Genetic Algorithm Optimized Grid-based RF Fingerprint Positioning in Heterogeneous Small Cell Networks
2015
In this paper we propose a novel optimization algorithm for grid-based RF fingerprinting to improve user equipment (UE) positioning accuracy. For this purpose we have used Multi-objective Genetic Algorithm (MOGA) which enables autonomous calibration of gridcell layout (GCL) for better UE positioning as compared to that of the conventional fingerprinting approach. Performance evaluations were carried out using two different training data-sets consisting of Minimization of Drive Testing measurements obtained from a dynamic system simulation in a heterogeneous LTE small cell environment. The robustness of the proposed method has been tested analyzing positioning results from two different area…
Experimental study on efficiency enhancement in Interior Permanent Magnet Synchronous machines
2015
This paper presents an experimental study on the efficiency variation occurring in an IPMSM (Interior Permanent Magnet Synchronous Motor) with respect to the direct axis current component and for several working conditions. Such investigation is the starting point for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. More in detail, a test bench is set up to carry out the measurements needed for the final power loss identification. The experimental investigation is developed by performing tests at different speed, magnetization and load conditions. From the obtained results, it can be stated that the IPMSM efficiency can be maximi…
Optimum Performance of Permanent Magnet Synchronous Generators Coupled to Wind Turbines
2007
In this paper a control algorithm for the efficiency improvement of permanent magnet synchronous generators (PMSG) is presented. The proposed algorithm reduces the losses of the generator without affecting its performances. In details, after a description of a dynamic model of the PMSG, which has been purposely modified in order to take into account the iron losses, the basic equations and the constraints to obtain the loss minimization are presented and discussed. Some simulations of a specific PMSG employing the proposed algorithm are performed. The results of these simulations show that enhancement of the efficiency up to 3% can be reached in comparison to a PMSG using a traditional cont…
Efficiency Maximization of Permanent Magnet Synchronous Generators Coupled to Wind Turbines
2007
In this paper a control algorithm for the efficiency improvement of permanent magnet synchronous generators (PMSG), the relative simulations and their results are presented. The proposed algorithm reduces the losses of the generator without affecting its performances. In details, after a description of a dynamic model of the PMSG, which has been modified in order to take into account the iron losses, the basic methodologies to obtain the loss minimization are presented and discussed. Many simulations of a specific PMSG employing the proposed algorithm were carried out and are presented. The results of these simulations show that enhancement of the efficiency up to 3% and more can be reached…
Simultaneous zonation and calibration of pipe network parameters
2003
A procedure for simultaneously zoning and calibrating pipe network parameters is proposed and applied to the determination of pipe resistance coefficients. The methodology is aimed at grouping the parameters of all the pipes into a small number of zone parameters, constrained to keep the difference between the computed and the measured water heads below a given tolerance. It is shown that, in the case of nonlooped networks, the methodology leads to a linear minimization problem where the objective function is a measure of the heterogeneity of the estimated parameters. In the case of looped networks an iterative procedure, where the linear problem is coupled with a nonlinear problem having a…
Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurati…
2022
In the present research, insights about the mechanisms of excess sludge minimization occurring in an oxic-settling-anaerobic (OSA) were provided. The investigation involved two systems operating in parallel. In particular, a conventional activated sludge (CAS) system as control and a system implementing the OSA process both having a pre-denitrification scheme were considered. Five periods (P1-P5) were studied, during which several operating conditions and configurations were tested. Specifically, the hydraulic retention time (HRT) in the anaerobic reactor of the OSA system (P1 8 h, P2-P3 12 h, P4 8 h, P5 12 h) and the return sludge from the anaerobic to the anoxic (scheme A) (P1-P2) or aero…
Comparison between ozonation and the OSA process: analysis of excess sludge reduction and biomass activity in two different pilot plants
2012
The excess biomass produced during biological treatment of municipal wastewater represents a major issue worldwide, as its disposal implies environmental, economic and social impacts. Therefore, there has been a growing interest in developing technologies to reduce sludge production. The main proposed strategies can be categorized according to the place inside the wastewater treatment plant (WWTP) where the reduction takes place. In particular, sludge minimization can be achieved in the wastewater line as well as in the sludge line. This paper presents the results of two pilot scale systems, to evaluate their feasibility for sludge reduction and to understand their effect on biomass activit…
Novel Biocompatible Cationic Copolymers Based on Polyaspartylhydrazide Being Potent as Gene Vector on Tumor Cells
2007
Introduction. The reaction between !,"-poly(aspartylhydrazide) (PAHy), a water soluble synthetic polymer and 3-(carboxypropyl)trimethyl-ammonium chloride (CPTACl) produced copolymers bearing permanent positive charges (PAHy–CPTA) with molecular weight of 10 kDa and PAHy–CPTA copolymers differing in positive charge amount (18–58%) were chosen for biological investigations. Materials and methods. Biophysical properties of DNA/PAHy–CPTA polyplexes were evaluated in terms of DNA condensation, zeta potential and size distribution. Cytotoxicity studies on Neuro2A murine neuroblastoma cells evidenced absence of toxicity of these copolymers up to 300 2g/ml unlike linear polyethylenimine (LPEI) that…