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Search Results: 1 - 10 of 445623 matches for " J. D. Rodrigues "
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Satellite rings and normal modes in rotating clouds of ultra cold atoms
J. D. Rodrigues,J. T. Mendon?a,J. A. Rodrigues
Physics , 2014,
Abstract: The multiple scattering of light in a gas of ultra cold atoms is responsible for many exciting features observed in magneto-optical traps including the collective behavior forced by a Coulomb like potential. This field also induces plasma like phenomena in the cloud which allows the treatment of the system as a one component trapped plasma. With a fluid description and casting the thermodynamical behavior in the form of a polytropic equation of state we investigate the equilibrium profiles of rotating clouds and its dependence on the experiment characteristics. Numerical solutions predict the formation of stable orbital modes both in rotating and non rotating clouds. We also investigate the normal modes on such rotating systems.
Enraizamento de estacas de lichia (Litchi chinensis Sonn.)
Leonel, S.;Rodrigues, J. D.;Rodrigues, S. D.;
Scientia Agricola , 1995, DOI: 10.1590/S0103-90161995000200022
Abstract: the effects of exogen auxins and boric add were studied on lychee (litchi chinensis sonn.) cuttings. cuttings were standardized to twenty-five cm length, with four leaves, cut in half. the bases of the cuttings were dipped of 2,5 cm in water solutions, resulting in the following treatments: h2o; boron 150 μg/ml; iba 5,000 ppm; iba 2,000 ppm; iba 5,000 ppm plus boron 150 μg/ml; iba 2,000 ppm plus boron 150 μg/ml; naa 3,000 ppm; naa 1,500 ppm; naa 3,000 ppm plus boron 150 μg/ml; naa 1,500 ppm plus boron 150 μg/ml. cutting was performed in september (southern hemisphere) and the cuttings were place in styrofoam trays, using vermiculite as substratum and kept under intermittent mist it was concluded that 5,000 ppm iba for one minute was the best treatment to improve rooting (83,33%), while the control (h2o) showed only 16,67% of rooted cuttings.
The Min System and Nucleoid Occlusion Are Not Required for Identifying the Division Site in Bacillus subtilis but Ensure Its Efficient Utilization
Christopher D. A. Rodrigues,Elizabeth J. Harry
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002561
Abstract: Precise temporal and spatial control of cell division is essential for progeny survival. The current general view is that precise positioning of the division site at midcell in rod-shaped bacteria is a result of the combined action of the Min system and nucleoid (chromosome) occlusion. Both systems prevent assembly of the cytokinetic Z ring at inappropriate places in the cell, restricting Z rings to the correct site at midcell. Here we show that in the bacterium Bacillus subtilis Z rings are positioned precisely at midcell in the complete absence of both these systems, revealing the existence of a mechanism independent of Min and nucleoid occlusion that identifies midcell in this organism. We further show that Z ring assembly at midcell is delayed in the absence of Min and Noc proteins, while at the same time FtsZ accumulates at other potential division sites. This suggests that a major role for Min and Noc is to ensure efficient utilization of the midcell division site by preventing Z ring assembly at potential division sites, including the cell poles. Our data lead us to propose a model in which spatial regulation of division in B. subtilis involves identification of the division site at midcell that requires Min and nucleoid occlusion to ensure efficient Z ring assembly there and only there, at the right time in the cell cycle.
ANALYSIS OF THE PREDICTIVE DMC CONTROLLER PERFORMANCE APPLIED TO A FEED-BATCH BIOREACTOR
RODRIGUES, J. A. D.;MACIEL FILHO, R.;
Brazilian Journal of Chemical Engineering , 1997, DOI: 10.1590/S0104-66321997000400009
Abstract: two control algorithms were implemented in the stabilization of the dissolved oxygen concentration of the penicillin process production phase. a deterministic and nonstructured mathematical model was used, where were considered the balances of cell, substrate, dissolved oxygen and product formation as well as kinetic of the growth, respiration, product inhibition due to excess of substrate, penicillin hydrolyze, yield factors among cell growth, substrate consumption and dissolved oxygen consumption. the bioreactor was operated in a feed-batch way using an optimal strategy for the operational policy. the agitation speed was used as manipulated variable in order to achieve the dissolved oxygen control because it was found to be the most sensitive one. two types of control configurations were implemented. first, the pid feedback control with the parameters estimated through modified simplex optimization method using the iae index, and second, the dmc predictive control that had as control parameters the model, prediction and control horizons as well as suppression factor and the trajectory parameter. a sensitivity analysis of these two control algorithms was performed using the sample time and dead time as the index to make stability evaluation. both configurations showed stable performance, however, the predictive one was found to be more robust in relation to the sample time, as well as the dead time variations. this is a very important characteristic to be considered for the implementation of control scheme in real fermentative process
Efeito da época de estaquia, fitorreguladores e ácido bórico no enraizamento de estacas de porta-enxertos de videira
Leonel, S.;Rodrigues, J.D.;
Scientia Agricola , 1993, DOI: 10.1590/S0103-90161993000100005
Abstract: the effects of indolebutyric, naphtalen acetic and boric acids were studied on rooting of grape rootstock cuttings. the cuttings were 25 cm long with two buds and were taken in three different times (january, april and july). rooting was carried out in styrofoam trays with vermiculite as substratum and under intermittent mist. cuttings were imersed up to 2.5 cm from the base in solutions for one minute. the treatments were: 1,000; 2,000 and 5,000 ppm of iba; 1,500 and 3,000 ppm of naa; 150 micrograms/ml h3bo3; iba 1,000; 2,000 and 5,000 ppm plus h3bo3150 niicrograins/ml and h2o. rooting percentage, average number of roots per cutting and average length of roots (mm) were evaluated 90 days after planting, in july. iba at 2,000 ppm was the best treatment with 88.8% of rooted cuttings. the best time for rooting was july (winter).
Efeitos da aplica??o de reguladores vegetais e do ácido bórico, em estacas de lichieira (Litchi chinensis Sonn.)
Leonel, S.;Rodrigues, J.D.;
Scientia Agricola , 1993, DOI: 10.1590/S0103-90161993000100006
Abstract: interactions between indolebutyric, naphtalen acetic and boric acids were studied on "callus" development and survival in lychee (litchi chinensis sonn.) cuttings. the cuttings were twenty five cm long with four leaves cut in half and taken in two different periods (january and april) styrofoam trays, with vermiculite as substratum kept under intermittent mist were used as rooting media. cuttings were imersed up to 2.5 cm from the base in water solutions, for one minute. the treatments were: 5,000 and 2,000 ppm of iba; 3,000 and 1,500 ppm of naa; 150 micrograms/ml h3bo3; iba 5,000 and 2,000 ppm plus h3bo3 150 micrograms/ml; naa 3,000 and 1,500 ppm plus boron 150 micrograms/ml and ii2o. "callus" formation and cutting survival were evaluated 120 days after planting. it was concluded that no treatments were effective on root formation, however, "callus" formation was observed. the best period for taking the cuttings was april.
EFEITOS DE GIBERELINAS, CITOCININAS E DO NITRATO DE POTáSSIO NO CRESCIMENTO E DESENVOLVIMENTO DO PORTA-ENXERTO DE LIMOEIRO `CRAVO'
LEONEL, S.;RODRIGUES, J.D.;
Scientia Agricola , 1996, DOI: 10.1590/S0103-90161996000200012
Abstract: the effects of gibberellins, cytokinins and potassium nitrate on the development of `rangpur'lime (citrus limonia osbeck) rootstocks were studied. seeds from ripe fruits were washed, dried and stored at 4 - 5o c for 60 days. they were planted in nursery plots in may/1993 and when the seedlings had 10 - 20 cm height, they were transplanted to a second nursery stage. the seedlings were sprayed at 15-day intervals, with plant regulators and potassium nitrate, after reaching the age of 8 months. from january to march/1993, the seedlings were sprayed with: 25, 50 and 75 ppm of ga3; 25, 50 and 75 ppm of ga4+7 + phenylmethyl-aminepurine; 20 ppm of phenylmethylpyranil-aminepurine; 0.2% of kno3. the seedlings planted in may/1993 did not reach earlier suitable size for budding when compared to the control. the treatments with kno3 0.2% showed a tendency to inhibit the seedling growth.
EFEITOS DE GIBERELINAS, CITOCININAS E DO NITRATO DE POTáSSIO NO CRESCIMENTO E DESENVOLVIMENTO DO PORTA-ENXERTO DE LIMOEIRO `CRAVO'
LEONEL S.,RODRIGUES J.D.
Scientia Agricola , 1996,
Abstract: Os efeitos de reguladores vegetais do grupo das giberelinas e citocininas, bem como do nitrato de potássio, foram estudados no crescimento e desenvolvimento do porta-enxerto de limoeiro `Cravo' (Citrus limonia Osbeck). As sementes foram extraídas de frutos maduros, lavadas, secas à sombra e armazenadas em camara fria (4 - 5oC) durante sessenta dias, até o mês de maio/1993, quando foram semeadas nos canteiros de semeadura. As pulveriza es com os fitorreguladores foram realizadas no viveiro e tiveram início com as plantas aos 8 meses de idade, contados a partir da semeadura, sendo efetuadas um total de 4 pulveriza es, realizadas a intervalos quinzenais. Os tratamentos corresponderam a: 25, 50 e 75 ppm de GA3; 25, 50 e 75 ppm de GA4+GA7+fenilmetil-aminopurina; 20 ppm de fenilmetilpiranil-aminopurina; 0,2% de KNO3 e testemunha (sem pulveriza o). Os resultados obtidos permitiram concluir que as pulveriza es com os reguladores vegetais e com o nitrato de potássio, realizadas no período de janeiro a mar o (ver o), n o tiveram efeito na diminui o do tempo de forma o das plantas jovens de limoeiro `Cravo', tendo inclusive, o tratamento com KNO3 0,2%, exercido efeito depressivo no desenvolvimento das mesmas.
ANALYSIS OF THE PREDICTIVE DMC CONTROLLER PERFORMANCE APPLIED TO A FEED-BATCH BIOREACTOR
RODRIGUES J. A. D.,MACIEL FILHO R.
Brazilian Journal of Chemical Engineering , 1997,
Abstract: Two control algorithms were implemented in the stabilization of the dissolved oxygen concentration of the penicillin process production phase. A deterministic and nonstructured mathematical model was used, where were considered the balances of cell, substrate, dissolved oxygen and product formation as well as kinetic of the growth, respiration, product inhibition due to excess of substrate, penicillin hydrolyze, yield factors among cell growth, substrate consumption and dissolved oxygen consumption. The bioreactor was operated in a feed-batch way using an optimal strategy for the operational policy. The agitation speed was used as manipulated variable in order to achieve the dissolved oxygen control because it was found to be the most sensitive one. Two types of control configurations were implemented. First, the PID feedback control with the parameters estimated through Modified Simplex optimization method using the IAE index, and second, the DMC predictive control that had as control parameters the model, prediction and control horizons as well as suppression factor and the trajectory parameter. A sensitivity analysis of these two control algorithms was performed using the sample time and dead time as the index to make stability evaluation. Both configurations showed stable performance, however, the predictive one was found to be more robust in relation to the sample time, as well as the dead time variations. This is a very important characteristic to be considered for the implementation of control scheme in real fermentative process
Noise in an SSET-resonator driven by an external field
D. A. Rodrigues,G. J. Milburn
Physics , 2008, DOI: 10.1103/PhysRevB.78.104302
Abstract: We investigate the noise properties of a superconducting single electron transistor (SSET) coupled to an harmonically driven resonator. Using a Langevin equation approach, we calculate the frequency spectrum of the SSET charge and calculate its effect on the resonator field. We find that the heights of the peaks in the frequency spectra depend sensitively on the amplitude of the resonator oscillation and hence suggest that the heights of these peaks could act as a sensitive signal for detecting the small changes in the amplitude of the drive. The previously known results for the effective amplitude-dependent damping and temperature provided by the SSET for the case of a low frequency resonator are generalized for all resonator frequencies.
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