Differential-Evolution-Based Optimization of the Dynamic Response for Parallel Operation of Inverters With No Controller Interconnection

In this paper, the use of differential evolution ( DE), a global search technique inspired by evolutionary theory, to find the parameters that are required to achieve optimum dynamic response of parallel operation of inverters with no interconnection among the controllers is proposed. Basically, in order to reach such a goal, the system is modeled in a certain way that the slopes of P-omega and Q-V curves are the parameters to be tuned. Such parameters, when properly tuned, result in system's eigenvalues located in positions that assure the system's stability and oscillation-free dynamic response with minimum settling time. This paper describes the modeling approach and provides an overview of the motivation for the optimization and a description of the DE technique. Simulation and experimental results are also presented, and they show the viability of the proposed method.

On the dynamic behaviour of a mass supported by a parallel combination of a spring and an elastically connected damper

This paper presents a consistent and concise analysis of the free and forced vibration of a mass supported by a parallel combination of a spring and an elastically supported damper (a Zener model). The results are presented in a compact form and the physical behaviour of the system is emphasised. This system is very similar to the conventional single-degree-of freedom system (sdof)-(Voigt model), but the dynamics can be quite different depending on the system parameters. The usefulness of the additional spring in series with the damper is investigated, and optimum damping values for the system subject to different types of excitation are determined and compared.There are three roots to the characteristic equation for the Zener model; two are complex conjugates and the third is purely real. It is shown that it is not possible to achieve critical damping of the complex roots unless the additional stiffness is at least eight times that of the main spring. For a harmonically excited system, there are some possible advantages in using the additional spring when the transmitted force to the base is of interest, but when the displacement response of the system is of interest then the benefits are marginal. It is shown that the additional spring affords no advantages when the system is excited by white noise. (c) 2007 Elsevier Ltd. All rights reserved.

FIR laser lines from CH3OD: A review

The methanol isotopic species CH3OD has also proved to be an efficient and powerful medium to generate radiation in the far infrared (FIR) region. After the critical review of 1994, six papers have been published dealing with new FIR laser lines from this molecule. As a consequence of the use of wide tunability waveguide CO2 lasers as well as a new pulsed CO2 laser operating at hot and sequential bands, as of optical pumping sources, the total number of the FIR laser lines increased from 122 in 1994 to 227 today. In this communication we present an updated and complete catalogue of FIR laser lines generated from CH3OD. Information on wavelength, offset, relative polarization, intensity, and optimum operation pressure is generally available.

New far-infrared laser lines from CH3OD methanol deuterated isotope

We report on a study of the CH3OD molecule in a search for new far-infrared (FIR) laser lines. For optical pumping of large offset vibrational absorption transitions, a continuous-wave waveguide CO2 laser with 300 MHz tunability around each line was used for the first time. As a consequence, 17. new far-infrared laser emissions were observed. For these lines, we also present data on wavelength, intensity, offset, relative polarization, and optimum operation pressure.

New laser lines from CHD2OH methanol deuterated isotope

Through the optical pump technique we have reinvestigated the CHD2OH molecule as a source of far-infrared (FIR) laser lines using for the first time a CO2 laser lasing on regular, hot, and sequence bands. As a consequence, we present here spectroscopic data of 16 now FIR laser transitions from this molecule. Furthermore, we also present a catalogue of all FIR laser lines generated from CHD2OH.

DCOOD optically pumped by a (CO2)-C-13 laser: new terahertz laser lines

In this work we report on new optically pumped THz laser lines from deuterated formic acid (DCOOD). An isotopic (CO2)-C-13 laser was used for the first time as a pump source for this molecule, and a Fabry-Perot cavity was used as a THz laser resonator. Optoacoustic absorption spectra were used as a guide to search for new THz laser lines. We could observe six new laser lines in the range from 303.8 mu m (0.987 THz) to 725.1 mu m (0.413 THz). The lines were characterized according to wavelength, relative polarization, relative intensity, and optimum working pressure. The transferred lamb-dip technique was used to measure the frequency absorption transition for both of these laser lines. Furthermore, we also present a catalogue of all THz laser lines generated from DCOOD.

New Terahertz Laser Lines From (13)CD(3)OH Pumped by Regular and Hot Bands CO(2) Laser

We have used our new pulsed CO(2) laser, operating both on regular and hot bands, to excite the (13)CD(3)OH methanol isotopomer. This has lead to the observation of 13 new high-threshold far-infrared laser emissions (also identified as terahertz laser lines), with frequencies in the range between 24.11 and 102.56 cm(-1) (0.72-3.07 THz). The absorption transitions leading to these new FIR laser emissions have been located by observing the optoacoustic absorption spectra around the CO(2) emissions. Here, we present these new far-infrared laser lines, characterized in wavelength, polarization, offset relative to the center of the pumping CO(2) laser transition, relative intensity, and optimum operation pressure.

Human breast tumor slices as an alternative approach to cell lines to individualize research for each patient

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ethyl Carbamate Analysis in German Fruit Spirits and Brazilian Sugarcane Spirits (Cachaca): Improved Sample Cleanup with Automated Parallel Evaporation

The analysis of alcoholic beverages for the important carcinogenic contaminant ethyl carbamate is very time-consuming and expensive. Due to possible matrix interferences, sample cleanup using diatomaceous earth (Extrelut) column is required prior to gas chromatographic and mass spectrometric measurement. A limiting step in this process is the rotary evaporation of the eluate containing the analyte in organic solvents, which is currently conducted manually and requires approximately 20-30 min per sample. This paper introduces the use of a parallel evaporation device for ethyl carbamate analysis, which allows for the simultaneous evaporation of 12 samples to a specified residual volume without manual intervention. A more efficient and, less expensive analysis is therefore possible. The method validation showed no differences between the fully-automated parallel evaporation and the manual operation. The applicability was proven by analyzing authentic spirit samples from Germany, Canada and Brazil. It is interesting to note that Brazilian cachacas had a relatively high incidence for ethyl carbamate contamination (55% of all samples were above 0.15 mg/l), which may be of public health relevance and requires further evaluation.

Toxicogenomic activity of gemcitabine in two TP53-mutated bladder cancer cell lines: special focus on cell cycle-related genes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cell cycle arrest and apoptosis in TP53 subtypes of bladder carcinoma cell lines treated with cisplatin and gemcitabine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Trans-enamel and trans-dentinal cytotoxic effects of a 35% H2O2 bleaching gel on cultured odontoblast cell lines after consecutive applications

To evaluate the trans-enamel and trans-dentinal cytotoxic effects of a 35% H2O2 bleaching gel on an odontoblast-like cell lines (MDPC-23) after consecutive applications.Fifteen enamel/dentine discs were obtained from bovine central incisor teeth and placed individually in artificial pulp chambers. Three groups (n = 5 discs) were formed according to the following enamel treatments: G1: 35% H2O2 bleaching gel (15 min); G2: 35% H2O2 bleaching gel (15 min) + halogen light (20 s); G3: control (no treatment). After repeating the treatments three consecutive times, the extracts (culture medium + gel components that had diffused through enamel/dentine discs) in contact with the dentine were collected and applied to previously cultured MDPC-23 cells (50 000 cells cm(-2)) for 24 h. Cell metabolism was evaluated by the MTT assay and data were analysed statistically (alpha = 5%; Kruskal-Wallis and Mann-Whitney U-test). Cell morphology was analysed by scanning electron microscopy.Cell metabolism decreased by 92.03% and 82.47% in G1 and G2 respectively. G1 and G2 differed significantly (P < 0.05) from G3. Regardless of halogen light activation, the application of the bleaching gel on the cultured odontoblast-like cells caused significantly more severe cytotoxic effects than those observed in the nontreated control group. In addition, significant morphological cell alterations were observed in G1 and G2.After three consecutive applications of a 35% H2O2 bleaching agent, the diffusion of the gel components through enamel and dentine caused severe toxic effects to cultured pulp cells.

Postoperative periodontal pain prevention using two dexamethasone medication protocols: A double-blind, parallel-group, placebo-controlled randomized clinical trial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)