Axial wedge effect in tilted hydrodynamic journal bearings

Hydrodynamic journal bearings are susceptible to static angular misalignment, resulting from improper assemblage, elastic and thermal distortion of the shaft and bearing housing, and also manufacturing errors. Several previous works on the theme, both theoretical and experimental, focused on the determination of the static properties of angular misaligned bearings. Although some reports show agreement between theoretical and experimental results, the increasingly severe operating conditions of hydrodynamic bearings (heavy loads and high rotational speeds) require more reliable theoretical formulations for the evaluation of the journal performance during the design process. The consideration of the angular misalignment in the derivation of the Reynolds equation is presented here in detail, showing that properly conducted geometric and magnitude-order analyses lead to the inclusion of an axial wedge effect term that influences the velocity and pressure fields in the lubricant film. Numerical results evidence that this axial wedge effect more significantly affects the hydrodynamic forces and static operational properties of tilted short journal bearings.

Physical, physicochemical and chemical characterization of turf, sulphur mud and fango for cosmetic application

Focusing on the therapeutic and cosmetic potentials of the thermal water, several processes were developed to achieve a raw material known as fango which presents in its constitution water, clay and organic soil. This research work aimed at characterizing turf, sulphur mud and fango from Araxa, MG, Brazil, through physical, physicochemical, inorganic and organic assessments for cosmetic and topical product proposes. The characterization permitted the determination of relevant parameters to suggest the efficacy (presence, of ions) and safety (absence of toxic metals) of those raw materials for cosmetic and pharmaceutical utilization.

Continuous reproduction and recruitment in the narrowback mud crab Panopeus americanus (Brachyura, Panopeidae) in a remnant human-impacted mangrove area

The population structure, reproductive period, and juvenile recruitment of Panopeus americanus were studied in order to enhance knowledge of its life cycle and reproductive strategy and promote the maintenance of its natural stocks in an impacted region. Specimens were collected in the remnant human-impacted mangrove at Araca, state of Sao Paulo, Brazil, at two-month intervals from January to November 2005, at low tide, with a capture effort by three people. The crabs were measured (carapace width, CW) and sexed. The total catch was 275 animals, including 132 males (48.0%); 127 females (46.2%), of which 39 were ovigerous (14.2% of total catch); and 16 individuals whose sex could not be identified (5.8%). No correlation was observed between water temperature and the number of collected individuals; however, there was a significant, positive correlation with salinity. Males were significantly larger than females. The size-frequency distribution was bimodal, reflecting the occurrende of more than one recruitment pulse and the differential abundance of adults during the period of study. The overall sex ratio was 1:0.97 favoring males, and was not significantly different from the expected value, i.e., this population fits the anomalous pattern of sex occurrence in size classes. Ovigerous females were captured in all sampled months, which explain the continuous recruitment observed. Expected low levels of individuals of different size classes in the population were not confirmed. All population aspects found here allowed us to infer that this population of P. americanus is well established in the impacted mangrove by virtue of its reproductive strategy.

Microdistribution of juveniles and adults of the mud crab Panopeus americanus (Brachyura, Panopeidae) in a remnant mangrove area in the southwest Atlantic

The distribution and density of a population of the narrowback mud crab Panopeus americanus were evaluated, with emphasis on the different developmental stages (juveniles and adults) and sexes. Specimens were collected in a remnant human-impacted mangrove at Araca on the northern coast of Sao Paulo, Brazil, at two-month intervals from January through July 2006, using 1m x 1m sample plots randomly distributed in the intertidal zone. The population was abundant, with a mean density of 14.3 +/- 9.3 individuals/m(2). Larger individuals were more abundant in the upper and middle intertidal zones, whereas smaller crabs were predominant in the lower intertidal and thus remained submerged longer. Males and juveniles were homogeneously distributed. Females preferred regions farther from the waterline. A clustered distribution pattern suggested gregarious behaviour and settling of juveniles in the vicinity of the adults` habitats, in an adaptive process as a function of tidal rhythms.

Thermal Characteristics of the Mud Nests of the Social Wasp Polybia spinifex (Hymenoptera; Vespidae)

The thermal characteristics of mud nests of Polybia spinifex were investigated by measuring internal and surface temperatures of the nests. The nests had a layer of mud envelope and consisted of mud with fine sand particles. The envelope had a vertically long slit-like entrance hole. The mud nests had high thermal conductivities (0.51-0.67 W/(m degrees C)) comparable to brick, rather than insulation materials of wasps` nests such as paper and wood. It was revealed that the long entrance radiated more heat from the thereto-image. The rate of thermal radiation (emissivity) of the nest surface was 0.80, and the value was similar to that of sand. The internal temperatures of the nests were high from top (T(n1), temperature difference between ambient temperature (T(a)) was 10 degrees C) to bottom (T(n3), difference, 5 degrees C) at noon. On the other hand, the temperature distributions were reversed during the night. Temperature T(n1) was lower by 1 degrees C than T(a), possibly from nightly dew on the top surface, whereas, at the middle point (T(n2),) and T(n3), temperatures were higher by 1 degrees C compared to T(a). Temperature fluctuations (ranges between maximum and minimum temperature) at T(n2) and T(n3) were similar to that of T(a), whereas the values at T(n1) and T(s) were higher than that of T(a).

Effectiveness of medial-wedge insole treatment for valgus knee osteoarthritis

Objective. To assess the efficacy of medial-wedge insoles in valgus knee osteoarthritis (OA). Methods. Thirty consecutive women with valgus-deformity knee OA a:8 degrees were randomized into 2 groups: medial insole (insoles with B-mm medial elevation at the rearfoot [n = 161) and neutral insole (similar insole without elevation [n = 14]). Both groups also wore ankle supports. A blinded examiner assessed pain on movement, at rest, and at night with a visual analog scale (VAS), the Lequesne index., and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Femorotibial, talocalcaneal, and talar tilt angles were evaluated at baseline and after 8 weeks of insole use. Results. Significant reductions in the medial insole group were observed for pain on movement (mean +/- SD VAS pre- and postintervention 8.1 +/- 1.5 versus 1 4.2 +/- 2.4; P = 0.001), at rest (5.1 +/- 2.3 versus 2.7 +/- 2.4; P = 0.002), and at night (6.1 +/- 2.7 versus 3.1 +/- 2.1; P = 0.001). In addition, a decrease in Lequesne (14.7 +/- 3.4 versus 9.6 +/- 3.8; P = 0.001) and WOMAC scores (74.1 +/- 14.2 versus 56.1 +/- 14.9; P = 0.001) was observed for the medial insole group. In the neutral insole group, a significant reduction was observed only for night pain (mean SD VAS pre- and postintervention 5.8 +/- 2.4 versus 4.6 +/- 2.4; P = 0.019). An increase in femorotibial angle (169.0 +/- 3.4 versus 170.8 +/- 2.4; P = 0.019). An increase in femorotibial angle (169.0 +/- 3.4 versus 170.8 +/- 3.7; P = 0.001) occurred only in the medial 3.7; P = 0.001) occurred only in the medial insole group. Moreover, the difference in measured fernorotibial angles pre- and postintervention was 1.84 +/- 1.42 versus -0.18 +/- 0.67 (P < 0.001) for the medial and neutral insole groups. Conclusion. The use of medial-wedge insoles was highly effective in reducing pain at rest and on movement and promoted a functional improvement of valgus knee OA.

The suitability of different FEA models for studying root fractures caused by wedge effect

Finite element analysis (FEA) utilizing models with different levels of complexity are found in the literature to study the tendency to vertical root fracture caused by post intrusion (""wedge effect""). The objective of this investigation was to verify if some simplifications used in bi-dimensional FEA models are acceptable regarding the analysis of stresses caused by wedge effect. Three plane strain (PS) and two axisymmtric (Axi) models were studied. One PS model represented the apical third of the root entirely, in dentin (PS-nG). The other models included gutta-percha in the apical third, and differed regarding dentin-post relationship: bonded (PS-B and Axi-B) or nonbonded (PS-nB and Axi-nB). Mesh discretization and material properties were similar for all cases. Maximum principal stress (sigma(max)) was analyzed as a response to a 165 N longitudinal load. Stress magnitude and orientation varied widely (PS-nG: 10.3 MPa; PS-B: 0.8 MPa; PS-nB: 10.4 MPa; Axi-13: 0.2 MPa, Axi-nB: 10.8 MPa). Axi-nB was the only model where all (sigma(max) vectors at the apical third were perpendicular to the model plane. Therefore, it is adequate to demonstrate the tendency to vertical root fractures caused by wedge effect. Axi-13 showed only part of the (sigma(max) perpendicular to the model plane while PS models showed sigma(max) on the model plane. In these models, sigma(max) orientation did not represent a situation where vertical root fracture would occur due to wedge effect. Adhesion between post and dentin significantly reduced (c) 2007 Wiley Periodicals, Inc.

Avaliação radiográfica da cobertura acetabular à cabeça femoral, após osteotomia tripla e aplicação de cunha sacroilíaca, em pelve de cadáveres de cães

Na tentativa de evitar algumas das dificuldades associadas à osteotomia pélvica tripla (OPT), foi desenvolvido experimentalmente o método de aplicação de cunha na junção sacroilíaca para aumentar a ventroversão acetabular. O objetivo deste estudo foi aplicar as técnicas de cunha sacroilíaca e OPT em cadáveres e avaliar radiograficamente a eficácia da ventroversão acetabular. Para tal, foram utilizados 10 cadáveres de cães, adultos, com 15-25 kg. Em cada hemipelve direita foi realizada OPT com placas de 20° e 40°. Na hemipelve esquerda foram aplicadas cunhas nas articulações sacroilíacas de 20° e 40°. Avaliações radiográficas em projeções ventrodorsais foram realizadas para mensuração da cobertura acetabular à cabeça femoral nas duas técnicas. De acordo com os dados obtidos pode-se observar que não houve diferença entre a técnica de OPT e o uso de cunha sacroilíaca utilizando implantes de 20° e 40°, mas ocorreu diferença significativa (p<0,05) entre os cães antes e após a aplicação dos implantes de 20° e 40°, e também entre os que receberam implantes de 20° e os de 40°. A aplicação de cunha sacroilíaca produziu resultados semelhantes à OPT, e também se mostrou como de mais fácil aplicação.

Adsorção competitiva de inibidor de corrosão usado em poços de perfuração de petróleo sobre aço, esmectita e arenito

A commercial corrosion inhibitor used in petroleum production was characterized by means of infrared spectroscopy and energy dispersive spectroscopy (EDS). Predicting the adsorption behavior of corrosion inhibitor onto steel, sandstone and esmectite is the key to improve working conditions. In this study, the adsorption kinetics of inhibitor formulations in HCl 15% or in Mud Acid (HCl 13,5% and ammonium bifluoride) onto steel, sandstone and esmectite was determined by means of spectrophotometry. Kinetic parameters indicated that adsorption of inhibitor in the presence of bifluoride was favored. Moreover, the adsorption constant rate was the largest when the substrate was esmectite.

Morfologia dos órgãos genitais masculinos do Jurará Kinosternon scorpioides (Chelonia: Kinosternidae)

Kinosternon scorpioides é uma pequena tartaruga semi-aquática, típica de água doce, de distribuição geográfica bastante diversificada, encontrada no estado do Maranhão, onde é denominada de jurará ou muçuã. Sua carne é uma excelente fonte de proteína e a despeito da legislação vigente, é comercializado nas praias e feiras da cidade de São Luís e consumido nos restaurantes sob a forma de farofa servida em casquinha. Os órgãos genitais do macho foram estudados visando fornecer dados morfológicos da própria espécie, que poderão ser utilizados na biologia reprodutiva voltada para ações de preservação em cativeiro. Compõe-se a amostra de 10 machos adultos, obtidos mediante apreensões do IBAMA-MA (Proc. nº 020.12.002400/99-31, licença nº 002/01), os quais foram eutanaziados conforme normas do Comitê de Ética do Curso de Medicina Veterinária, Universidade Estadual do Maranhão. A cavidade celomática foi aberta e os órgãos fixados em solução aquosa de formaldeído 10%, e posteriormente dissecados. Os testículos possuem formato ovóide e coloração amarelo-ouro. Os epidídimos convolutos estavam aderidos dorsalmente à superfície medial dos testículos, terminando em um pequeno ducto deferente. Os ductos deferentes não forma-ram nenhuma ampola distinta, abrindo-se na cloaca. O pênis sulcado, localizado no assoalho da cloaca, estendeu-se até a cauda, composto de raíz, corpo e glande. A morfologia dos órgãos reprodutivos destes animais assemelha-se aos de outras tartarugas, sugerindo uma morfologia conservada entre as tartarugas.

Outflow occlusion for circulatory arrest in dogs

The purpose of this study was to evaluate the possibility of producing circulatory arrest by occlusion of the pulmonary trunk as an alternative to the venous inflow occlusion through the left hemithorax. Eight healthy mongrel dogs were divided in two groups. Group I underwent 4 minutes of outflow occlusion and Group II was submitted to 8 minutes of circulatory arrest. Outflow occlusion was performed through left thoracotomy and pericardiotomy by passing a Rumel tourniquet around the pulmonary trunk. Physical examination, electrocardiography, echocardiography, blood gas analyses, hemodynamic, and oxygen transport variables were obtained before and after the procedure. The dogs from Group I did not have any clinical, electrocardiographic, echocardiographic, or hemo-dynamic abnormalities after anesthetic recover. In the Group II, only one dog survived, which had no clinical, electrocardiographic, or echocardiographic abnormalities. In this last dog, just after releasing the occlusion, it was detected increases in the following parameters: heart rate (HR), systolic, diastolic and mean arterial blood pressure (SAP; DAP; MAP), pulmonary artery pressure (PAP), pulmonary wedge pressure (PWP), central venous pressure (CVP), cardiac output (CO), systolic index (SI), cardiac index (CI), left and right ventricular stroke work (LVSW; RVSW), oxygen delivery index (DO2), oxygen consumption index (VO2), and oxygen extraction (O2 ext). Moreover, the oxygen content of arterial and mixed venous blood (CaO2; CvO2), and the arterial and mixed venous partial pressure of oxygen (PaO2; PvO2) were decreased 5 minutes after circulatory arrest. Outflow occlusion is a feasible surgical procedure for period of 4 minutes of circulatory arrest.

Patterns of distribution of the hermit crab Loxopagurus loxochelis (Moreira, 1901) (Decapoda, Diogenidae) in two coastal areas of southern Brazil

The present study determined the distribution pattern of the hermit crab Loxopagurus loxochelis by a comparison of catch, depth and environmental factors at two separate bays (Caraguatatuba and Ubatuba) of Sao Paulo State, Brazil. The influence of these parameters on the distribution of males, non- ovigerous females and ovigerous females was also evaluated. Crabs were collected monthly, over a period of one year (from July/2002 to June/2003), in seven depths, from 5 to 35 m. Abiotic factors were monitored as follows: superficial and bottom salinity (psu), superficial and bottom temperature (C), organic matter content (%) and sediment composition (%). In total, 366 hermit crabs were sampled in Caraguatatuba and 126 in Ubatuba. The highest frequency of occurrence was verified at 20 m during winter (July) in Caraguatatuba and 25 m during summer (January) in Ubatuba. The highest occurrences were recorded in the regions with bottom salinities ranging from 34 to 36 psu, bottom temperatures from 18 to 24 C and, low percentages of organic matter, gravel and mud; and large proportion of sand in the substrate. There was no significant correlation between the total frequency of organisms and the environmental factors analyzed in both regions. This evidence suggests that other variables as biotic interactions can influence the pattern of distribution of L. loxochelis in the analyzed region, which is considered the limit of the northern distribution of this species.

Comparison of the effects of carbon dioxide and helium pneumoperitoneum on renal function

Background and Purpose: Carbon dioxide pneumoperitoneum is associated with significant hypercarbia and acidosis. The aim of this study is to evaluate the effects of carbon dioxide and helium pneumoperitoneum on renal function. Materials and Methods: Thirty adult dogs were put randomly into one of three groups ( n = 10 animals each): group A - pneumoperitoneum not performed; group B - CO2 pneumoperitoneum; and group C - helium pneumoperitoneum. The groups were analyzed with consideration given to body weight, hematologic values, hemodynamic parameters ( heart rate, mean arterial pressure, central venous pressure, cardiac output, stroke volume, systemic vascular resistance, pulmonary vascular resistance, left cardiac work index, cardiac index, mean pulmonary artery pressure, and pulmonary capillary wedge pressure), and renal function ( plasma renin activity, urinary output, creatinine clearance, and sodium excretory fraction). Results: An accentuated decrease in urinary output was observed during pneumoperitoneum in groups B and C compared to the control group. In groups B and C, creatinine clearance declined significantly during pneumoperitoneum in comparison to group A, but after deflation a faster recovery of glomerular filtration was noticed for group C, and a significant increase in sodium excretory fraction was seen for group B. On the other hand, in comparison to the control group, group B had a significant increase in plasma renin activity, with late recovery of glomerular function. Conclusion: Helium ameliorates renal alterations when used for pneumoperitoneum, and it might be used for patients with compromised renal function who have to undergo laparoscopic surgery.

Effects of drill cuttings discharge on meiofauna communities of a shelf break site in the southwest Atlantic

The present study investigates the effects of drill cutting discharges on the structure of meiofauna communities in an area of the shelf break at Campos Basin, Southeast Brazil. Drilling activities were operated, in a first phase, with water-based fluid and, in a second phase, with synthetic fluid paraffin-based (NAF-III). A total of 135 samples taken at a pre-drilling situation (MS1) and two post-drilling moments (MS2 and MS3-3 and 22 months post-drilling, respectively) were analyzed. Effects on meiofauna were dependent on two main factors: 1-the impact received during drilling operation, if water-based or synthetic/water-based drilling fluid and 2-the background state, if it already presented signs of previous drilling activities or not. Based on univariate and multivariate analysis, there were evidences that the most affected area after drilling was those under the influence of synthetic-based fluid and that already had signs of previous drillings activities. The region impacted only by water-based fluid was less affected and the only one that completely recovered after 22 months. Nematodes and copepods had different responses to the impact. While copepods flourish in the impacted area and recovered 22 months after drilling, nematodes were adversely affected shortly after drilling and the community structure only recovered where hydrocarbons had been depleted.