Hydrodynamics in the Blade Region of a Self-Aspirating Disk Impeller

In studies of self-aspirating impellers found that gas bubbles are not broken down by the impeller blades. Break-up of bubbles is caused by the eddies generated by the blades. Therefore, to describe how the liquid flow near the blades is an important research issue for this type of impellers. Using the PIV method average velocity fields in the axial-radial plane between baffles in the stirred tank were defined for seven different positions of blades of a self-aspirating disk impeller in relation to that plane. It was found that in the small space in blade vicinity, big changes in fluid circulation were observed depending on the position of the blade relative to the baffle. In front of blade the liquid from bottom and from over impeller is directed radially towards the wall of tank and the average axial velocity is zero. Behind the blade the cavern (cavity) is formed, understood as a space of reduced pressure. Underpressure causes suction effect which directs the liquid inside the cavern. In just a few millimeters from the blade tip average axial and radial velocities are equal to zero. In this region the tangential component of velocity is dominant

Context-Dependent Arm Pointing Adaptation

We sought to determine the effectiveness of head posture as a contextual cue to facilitate adaptive transitions in manual control during visuomotor distortions. Subjects performed arm pointing movements by drawing on a digitizing tablet, with targets and movement trajectories displayed in real time on a computer monitor. Adaptation was induced by presenting the trajectories in an altered gain format on the monitor. The subjects were shown visual displays of their movements that corresponded to either 0.5 or 1.5 scaling of the movements made. Subjects were assigned to three groups: the head orientation group tilted the head towards the right shoulder when drawing under a 0.5 gain of display and towards the left shoulder when drawing under a 1.5 gain of display, the target orientation group had the home & target positions rotated counterclockwise when drawing under the 0.5 gain and clockwise for the 1.5 gain, the arm posture group changed the elbow angle of the arm they were not drawing with from full flexion to full extension with 0.5 and 1.5 gain display changes. To determine if contextual cues were associated with display alternations, the gain changes were returned to the standard (1.0) display. Aftereffects were assessed to determine the efficacy of the head orientation contextual cue. . compared to the two control cues. The head orientation cue was effectively associated with the multiple gains. The target orientation cue also demonstrated some effectiveness while the.arm posture cue did not. The results demonstrate that contextual cues can be used to switch between multiple adaptive states. These data provide support for the idea that static head orientation information is a crucial component to the arm adaptation process. These data further define the functional linkage between head posture and arm pointing movements

Interrelationship between serum and sputum inflammatory mediators in chronic obstructive pulmonary disease

Little is known about airway inflammatory markers in chronic obstructive pulmonary disease (COPD). The objective of the present study was to identify and try to correlate pulmonary and peripheral blood inflammatory markers in COPD. In a cross-sectional study on patients with stable COPD, induced sputum and blood samples were collected for the determination of C-reactive protein, eosinophilic cationic protein, serum amyloid A protein, a-1 antitrypsin (a-1AT), and neutrophil elastase. Twenty-two patients were divided into two groups according to post-bronchodilator forced expiratory volume in the first second (%FEV1): group 1 (N = 12, FEV1 <40%) and group 2 (N = 10, FEV1 ³40%). An increase in serum elastase, eosinophilic cationic protein and a-1AT was observed in serum markers in both groups. Cytology revealed the same total number of cells in groups 1 and 2. There was a significantly higher number of neutrophils in group 1 compared to group 2 (P < 0.05). No difference in eosinophils or macrophages was observed between groups. Serum elastase was positively correlated with serum a-1AT (group 1, r = 0.81, P < 0.002 and group 2, r = 0.83, P < 0.17) and negatively correlated with FEV1 (r = -0.85, P < 0.03 and -0.14, P < 0.85, respectively). The results indicate the presence of chronic and persistent pulmonary inflammation in stable patients with COPD. Induced sputum permitted the demonstration of the existence of a subpopulation of cells in which neutrophils predominated. The serum concentration of all inflammatory markers did not correlate with the pulmonary functional impairment

Effects of an aerobic physical training program on psychosocial characteristics, quality-of-life, symptoms and exhaled nitric oxide in individuals with moderate or severe persistent asthma

OBJETIVO: Avaliar o papel de um programa de condicionamento físico aeróbio nos aspectos psicossociais, qualidade de vida, sintomas e óxido nítrico exalado (NOe) de adultos com asma persistente moderada ou grave. MATERIAIS E MÉTODOS: Vinte pacientes foram divididos aleatoriamente em Grupo Controle (GC, n= 10; programa de educação e exercícios respiratórios) e Grupo Treinado (GT, n= 10; programa de educação e exercícios respiratórios mais condicionamento aeróbio, 70% potência máxima obtida). A intervenção aconteceu duas vezes por semana durante três meses. Antes e após, foram avaliados a capacidade aeróbia máxima, a função pulmonar, a dispnéia ao esforço, os níveis de ansiedade e depressão e a qualidade de vida. Mensalmente, eram avaliados o NOe em repouso e o número de dias livres de sintomas. RESULTADOS: Apenas o GT apresentou redução dos sintomas (GT 24,8 [IC95%= 23-27] versus GC 15,7 [IC95%= 9-21] dias livres de sintomas, p< 0,05), dos níveis de NOe (GT 25,8 [IC95%= 15,3-44] versus GC 44,3 [IC95%= 24-60] ppb, p< 0,05), da ansiedade (GT 39,3 [IC95%= 37-50] versus GC 40,9 [IC95%= 37-50] escore, p< 0,001) e da depressão (GT 6,6 [IC95%= 1-21] versus GC 9 [IC95%= 1-20] escore, p< 0,001), melhora da qualidade de vida (GT 42,8 [IC95%= 34,3-71,7] versus GC 69,7 [IC95%= 45,1-87,9] %, p< 0,001), e incremento da aptidão aeróbia (GT 25,7 [IC95%= 16,2-31,3] versus GC 20,5 [IC95%= 17,3-24,1] mL/kg/min, p< 0,001). CONCLUSÕES: Os resultados sugerem que o treinamento físico reduz o NOe, os sintomas e melhora a qualidade de vida e os aspectos psicossociais de adultos com asma persistente moderada ou grave.OBJECTIVE: To evaluate the role of an aerobic physical training program on psychosocial characteristics, quality of life, symptoms and exhaled nitric oxide of adults with moderate or severe persistent asthma. METHODS: Twenty patients were randomly assigned to a Control Group (CG, n= 10, education program and respiratory exercises) and a Trained Group (TG, n= 10, education program and respiratory exercises plus aerobic training at 70% of the maximum power obtained). The intervention took place twice a week for three months. Maximum aerobic capacity, pulmonary function, effort dyspnea, anxiety levels, depression levels and quality of life were assessed before and after the treatment. Exhaled nitric oxide at rest and the number of days without asthma symptoms were evaluated every month. RESULTS: The TG presented increased numbers of symptom-free days (TG 24.8 days [95%CI= 23-27] versus CG 15.7 days [95%CI= 9-21]; p< 0.05), decreased exhaled nitric oxide levels (TG 25.8 ppb [95%CI= 15.3-44.0] versus CG 44.3 ppb [95%CI= 24-60]; p< 0.05), decreased anxiety scores (TG 39.3 [95%CI= 37-50] versus CG 40.9 [95%CI= 37-50]; p< 0.001), decreased depression scores (TG 6.6 [95%CI= 1-21] versus CG 9 [95%CI= 1-20]; p< 0.001), improved quality of life (TG 42.8% [95%CI= 34.3-71.7] versus CG 69.6% [95%CI= 45.1-87.9]; p< 0.001) and improved aerobic aptitude (TG 25.7 mL/kg/min [95%CI= 6.2-31.3] versus CG 20.5 mL/kg/min [95%CI= 17.3-24.1]; p< 0.001). CONCLUSIONS: Our results suggest that physical training reduces exhaled nitric oxide and symptoms and improves the quality of life and psychosocial characteristics of adults with moderate or severe persistent asthma.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Pesquisa (CNPq

Quantum Stephani Universe in vicinity of the symmetry center

We study a class of spherically symmetric Stephani cosmological models in the presence of a self-interacting scalar field in both classical and quantum domains. We discuss the construction of `canonical' wave packets resulting from the solutions of a class of Wheeler-DeWitt equations in the Stephani Universe. We suggest appropriate initial conditions which result in wave packets containing some desirable properties, most importantly good classical and quantum correspondence. We also study the situation from de-Broglie Bohm interpretation of quantum mechanics to recover the notion of time and compare the classical and Bohmian results. We exhibit that the usage of the canonical prescription and appropriate choices of expansion coefficients result in the suppression of the quantum potential and coincidence between classical and Bohmian results. We show that, in some cases, contrary to Friedmann-Robertson-Walker case, the bound state solutions also exist for all positive values of the cosmological constant.Comment: 22 pages, 19 figures, to appear in JCA

Quantum Stephani exact cosmological solutions and the selection of time variable

We study perfect fluid Stephani quantum cosmological model. In the present work the Schutz's variational formalism which recovers the notion of time is applied. This gives rise to Wheeler-DeWitt equation for the scale factor. We use the eigenfunctions in order to construct wave packets for each case. We study the time-dependent behavior of the expectation value of the scale factor, using many-worlds and deBroglie-Bohm interpretations of quantum mechanics.Comment: 19 pages, 7 figure

Turbulent Energy Dissipation Rate and Turbulence Scales in the Blade Region of a Self-Aspirating Disk Impeller

Instantaneous radial and axial velocitieques of water in the tank with a self-aspirating disk impeller operating without gas dispersion were measured by the PIV method. A comparison of mean square velocity pulsations confirmed previous observations that the area in which turbulence is non-isotropic is small and extends about 3 mm above and under the impeller and radially 12,5 mm from the impeller blade tip. Based on velocity measurements, the distributions of energy dissipation rates were determined using the dimensional equation = C•u’3/D and Smagorinsky model. Adoption of the results of the dimensional equation as a reference value allowed us to determine the Smagorinsky constant value. This value appeared to be smaller than the values given in the literature. It has been shown that eddies in a small space near the impeller had sufficient energy to break up gas bubbles flowing out of the impeller. Based on the obtained energy dissipation rate distributions, appropriate turbulence scales were determined

Black Holes with Weyl Charge and Non-Riemannian Waves

A simple modification to Einstein's theory of gravity in terms of a non-Riemannian connection is examined. A new tensor-variational approach yields field equations that possess a covariance similar to the gauge covariance of electromagnetism. These equations are shown to possess solutions analogous to those found in the Einstein-Maxwell system. In particular one finds gravi-electric and gravi-magnetic charges contributing to a spherically symmetric static Reissner-Nordstr\"om metric. Such Weyl ``charges'' provide a source for the non-Riemannian torsion and metric gradient fields instead of the electromagnetic field. The theory suggests that matter may be endowed with gravitational charges that couple to gravity in a manner analogous to electromagnetic couplings in an electromagnetic field. The nature of gravitational coupling to spinor matter in this theory is also investigated and a solution exhibiting a plane-symmetric gravitational metric wave coupled via non-Riemannian waves to a propagating spinor field is presented.Comment: 18 pages Plain Tex (No Figures), Classical and Quantum Gravit