256 research outputs found
Coherent Structures in Nonlocal Dispersive Active-Dissipative Systems
We analyze coherent structures in non-local dispersive active-dissipative nonlinear systems, using as a prototype the Kuramoto-Sivashinsky (KS) equation with an additional non-local term that contains stabilizing/ destabilizing and dispersive parts. As for the local generalized Kuramoto-Sivashinsky (gKS) equation (see, e.g., T. Kawara and S. Toh, Phys. Fluids, 31, 2103, 1988), we show that sufficiently strong dispersion regularizes the chaotic dynamics of the KS equation and the solutions evolve into arrays of interacting pulses that can form bound states. We analyze the asymptotic characteristics of such pulses and show that their tails tend to zero algebraically but
not exponentially as for the local gKS equation. Since the Shilnikov-type approach is not applicable for analyzing bound states in non-local equations, we develop a weak-interaction theory and show that the standard first-neighbor approximation is not applicable anymore. It is then essential to take into account long-range interactions due to the
algebraic decay of the tails of the pulses. In addition, we find that the number of possible bound-states for fixed parameter values is always finite, and we determine when there is long-range attractive or repulsive force between the pulses. Finally, we explain the regularizing effect of dispersion by showing that, as dispersion is increased, the
pulses generally undergo a transition from absolute to convective instability. We also find find that for some nonlocal operators, increasing the strength of the stabilizing/destabilizing term can have a regularizing/de-regularizing effect on the dynamics
Grande Queimado numa Unidade de Cuidados Intensivos Pediátricos – Experiência de 20 Anos
Introdução: A abordagem inicial do grande queimado até à sua estabilização hemodinâmica e hidroeletrolÃtica é fundamental para diminuir a morbimortalidade.
Material e Métodos: Estudo retrospectivo, descritivo e analÃtico, de todos os internamentos por queimadura numa Unidade
de Cuidados Intensivos Pediátricos durante o perÃodo de 20 anos (Abril/1991 a Dezembro/2010). Avaliaram -se parâmetros nosodemográficos, agente causal, gravidade e extensão da queimadura, procedimentos, terapêutica, complicações e resultados.
Resultados: Ocorreram 137 internamentos por queimadura correspondentes a 123 doentes e a 1,8% do total de internamentos
na UCIP. A mediana de idade foi 3,6 anos e 62,4% era do sexo masculino. Verificou -se maior incidência em Agosto (13,0%). Foram agentes da queimadura: lÃquido fervente
(38,1%), fogo (38,1%) e eletricidade (23,9%). A mediana da superfÃcie
corporal queimada foi de 30% (0,5 -92,0%), com queimaduras do terceiro grau em 59,0% dos doentes. Necessitaram de ventilação mecânica 45,5% e de cateter venoso central 64,2% dos doentes. As complicações incluÃram: sépsis (29,2%), falência
respiratória (21,1%), falência cardiovascular (16,5%) e falência
multiorgânica (18,8%). Verificou -se melhoria em 88,6% dos casos e ocorreram 10 óbitos (8,1%), nove dos quais nos primeiros 10 anos do estudo e nove devido a causa infeciosa. No entanto, o score avaliador do risco de mortalidade (PRISM), Ãndice de intervenção terapêutica (TISS) e o risco de probabilidade de morte (RPM) foram mais elevados no segundo decénio.
Conclusões: Nos últimos anos do estudo, apesar do maior número de admissões e da sua maior gravidade, verificou -se
uma diminuição do número de mortes, o que poderá dever-se à melhoria dos cuidados prestados
Ethanol production from hydrolyzed kraft pulp by mono- and co-cultures of yeasts: the challenge of C6 and C5 sugars consumption
Second-generation bioethanol production’s main bottleneck is the need for a costly and
technically di cult pretreatment due to the recalcitrance of lignocellulosic biomass (LCB). Chemical
pulping can be considered as a LCB pretreatment since it removes lignin and targets hemicelluloses
to some extent. Chemical pulps could be used to produce ethanol. The present study aimed to
investigate the batch ethanol production from unbleached Kraft pulp of Eucalyptus globulus by
separate hydrolysis and fermentation (SHF). Enzymatic hydrolysis of the pulp resulted in a glucose
yield of 96.1 3.6% and a xylose yield of 94.0 7.1%. In an Erlenmeyer flask, fermentation of the
hydrolysate using Saccharomyces cerevisiae showed better results than Sche ersomyces stipitis. At both
the Erlenmeyer flask and bioreactor scale, co-cultures of S. cerevisiae and S. stipitis did not show
significant improvements in the fermentation performance. The best result was provided by S.
cerevisiae alone in a bioreactor, which fermented the Kraft pulp hydrolysate with an ethanol yield
of 0.433 g g1 and a volumetric ethanol productivity of 0.733 g L1 h1, and a maximum ethanol
concentration of 19.24 g L1 was attained. Bioethanol production using the SHF of unbleached Kraft
pulp of E. globulus provides a high yield and productivity.publishe
Getting Value from Pulp and Paper Industry Wastes: On the Way to Sustainability and Circular Economy
The pulp and paper industry is recognized as a well-established sector, which throughout its process, generates a vast amount of waste streams with the capacity to be valorized. Typically, these residues are burned for energy purposes, but their use as substrates for biological processes could be a more efficient and sustainable alternative. With this aim, it is essential to identify and characterize each type of waste to determine its biotechnological potential. In this context, this research highlights possible alternatives with lower environmental impact and higher revenues. The bio-based pathway should be a promising alternative for the valorization of pulp and paper industry wastes, in particular for bioproduct production such as bioethanol, polyhydroxyalkanoates (PHA), and biogas. This article focuses on state of the art regarding the identification and characterization of these wastes, their main applied deconstruction technologies and the valorization pathways reported for the production of the abovementioned bioproductspublishe
INITIAL HIGH ELECTRIC FIELD – VACUUM ARC BREAKDOWN TEST RESULTS FOR ADDITIVELY MANUFACTURED PURE COPPER ELECTRODES
Additive Manufacturing (AM) is already wellestablished for various manufacturing pplications,
providing many benefits such as design freedom, novel and complex cooling designs for the parts and different performance improvements, as well as significantly reducing the production time. With the mentioned characteristics, AM is also being considered as a
technology for manufacturing a Radio Frequency Quadrupole (RFQ) prototype. For this application, an important parameter is the voltage holding capability of the surfaces. Furthermore, the voltage holding capability of pure copper surfaces manufactured by AM is of interest for the accelerator community at large for prospective future developments. To characterize these properties, a series of high electric field tests were performed on pure copper electrodes produced by AM, using the CERN pulsed highvoltage DC system. The tests were carried out with AM produced electrodes with large surface roughness. During
the testing process, a high vacuum was maintained. The electric breakdown rate was also monitored to ensure not to exceed the breakdown limit of 10ିହ breakdowns per pulse. The achieved results provide the first, initial reference values for the performance of AM built pure
copper electrodes for vacuum arc breakdown testing. Initial results prove the capability of AM electrodes to hold a high electric field, while having low breakdown rates. These are crucial results for further AM technology usage for different AM pure-copper accelerator components
Composição corporal de frangos de corte alimentados com dietas fareladas e peletizadas contendo milheto grão ou moÃdo
Projeto/Plano de Ação: 16.00.30.00
Emprego do modelo da taxa de crescimento de frutos em programa de raleio de macieira "Fuji Suprema".
Apresenta a descrição de experimento de raleio quÃmico com benziladenina e um tratamento controle realizados para validar o modelo matemático da taxa de crescimento dos frutos com a cultivar 'Fuji Suprema'. O resultado indica que o modelo de taxa de crescimento de frutos foi efetivo na previsão do número de frutos por planta e permitiu uma avaliação antecipada da eficiência do raleio quÃmico, sendo que o tratamento com duas aplicações foi o mais indicado para o raleio de macieiras 'Fuji Suprema'.bitstream/item/215653/1/CircTec152.pd
A method for the reconstruction of unknown non-monotonic growth functions in the chemostat
We propose an adaptive control law that allows one to identify unstable
steady states of the open-loop system in the single-species chemostat model
without the knowledge of the growth function. We then show how one can use this
control law to trace out (reconstruct) the whole graph of the growth function.
The process of tracing out the graph can be performed either continuously or
step-wise. We present and compare both approaches. Even in the case of two
species in competition, which is not directly accessible with our approach due
to lack of controllability, feedback control improves identifiability of the
non-dominant growth rate.Comment: expansion of ideas from proceedings paper (17 pages, 8 figures),
proceedings paper is version v
CaracterÃsticas da carcaça de frangos alimentados com dietas fareladas e peletizadas contendo milheto grão e moÃdo.
Projeto/Plano de Ação: 16.00.30.00
Plasma Electronics
Contains research objectives and reports on six research objectives.National Science Foundation (Grant G-24073)Lincoln Laboratory, Purchase Order DDL BB-107U. S. Air Force under Contract AF 19(628)-50
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