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Alternativa de reciclagem de resíduos de espuma rígida de poliuretano com ABS
Bom, R.P.;
Matéria (Rio de Janeiro) , 2008, DOI: 10.1590/S1517-70762008000200018
Abstract: the main aim of this paper is to carry out abs/pur mixtures with different concentrations of pur. the pur residues originate from the manufacture of refrigerators and freezers. the use of this type of residue generates environment problems when discharging this material. the homogenization of each mixture was made with a single screw extruder. a part of the extruded and granulated material was used for the accomplishment of assays of melt flow index (mfi) and another part was used in the process of moulding specimens by injection, in order to determine the specific mass and also obtain some samples of technical parts. the results of the assays of fluidity index had been initially transformed into volumetric outflow. for this to happen, the values of determined specific mass for the respective mixtures had been used. later, by means of rheologic equations the the viscosity of the different mixtures was calculated at 220oc. a rheologic curve was interpolated on the points for each case. assays of traction had been carried out in the specimens injected with different concentrations, which determined that the modulus of elasticity increases linearly with the increase of the pur concentration and the maximum tension supported by the material decreases with the pur increment. it was determined that the increase of the viscosity of the mixtures provoked variations in the injection process, even though, it was possible to inject different lots of technical parts. considering the mechanical and rheological properties obtained for the mixtures it could be concluded that the manufacture of some types of components could be viable.
The control of deliberate waiting strategies in a stop-signal task
Sylwan, R.P.;
Brazilian Journal of Medical and Biological Research , 2004, DOI: 10.1590/S0100-879X2004000600011
Abstract: to inhibit an ongoing flow of thoughts or actions has been largely considered to be a crucial executive function, and the stop-signal paradigm makes inhibitory control measurable. stop-signal tasks usually combine two concurrent tasks, i.e., manual responses to a primary task (go-task) are occasionally countermanded by a stimulus which signals participants to inhibit their response in that trial (stop-task). participants are always instructed not to wait for the stop-signal, since waiting strategies cause the response times to be unstable, invalidating the data. the aim of the present study was to experimentally control the strategies of waiting deliberately for the stop-signal in a stop-task by means of an algorithm that measured the variation in the reaction times to go-stimuli on-line, and displayed a warning legend urging participants to be faster when their reaction times were more than two standard deviations of the mean. thirty-four university students performed a stop-task with go- and stop-stimuli, both of which were delivered in the visual modality and were lateralized within the visual field. the participants were divided into two groups (group a, without the algorithm, vs group b, with the algorithm). group b exhibited lower variability of reaction times to go-stimuli, whereas no significant between-group differences were found in any of the measures of inhibitory control, showing that the algorithm succeeded in controlling the deliberate waiting strategies. differences between deliberate and unintentional waiting strategies, and anxiety as a probable factor responsible for individual differences in deliberate waiting behavior, are discussed.
Flow Characteristics in a Rotating Circular Flume
R.P. Rudra
The Open Civil Engineering Journal , 2007, DOI: 10.2174/1874149500701010030]
Abstract: Increased construction activity and associated receiving water concerns in the Greater Toronto Area has prompted this study to advance our knowledge on cohesive sediment transport processes in rivers and lake environments. Flow characteristics in a rotating circular flume at the National Water Research Institute (NWRI), Burlington, Ontario were studied using a computational fluid dynamics (CFD) model. The objective of this study was to use a CFD model to predict the complex 3D turbulent flow characteristics, including the tangential flow velocity distribution, turbulent secondary flow circulation patterns, and the bed shear stress distributions. The numerical model was calibrated using experimental data collected using a Laser Doppler Anemometer for velocity profiles and measurements obtained by a Preston tube for bed shear stress distributions. Tangential velocity profiles and bed shear velocity distributions across the rotating circular flume were used to evaluate the accuracy of the model predictions. When compared with experimental smooth bed shear stress data, the model performed reasonably well for the range of flume speeds examined. The calibrated CFD model was then used for simulating a series of 210 scenarios using varying ring operating speeds over a range of flow depths and bed roughness heights. The numerical simulation results were then used to study the complex 3D turbulent flow conditions in the circular flume at NWRI, including velocity profiles, turbulence characteristics of flow and bed shear stress distributions.
Inventory model with different demand rate and different holding cost
R.P. Tripathi
International Journal of Industrial Engineering Computations , 2013, DOI: 10.5267/j.ijiec.2013.03.001
Abstract: This paper deals with the development of an inventory model for time varying demand and constant demand; and time dependent holding cost and constant holding cost for case 1 and case 2 respectively. Previous models incorporating that the holding cost is constant for the entire inventory cycle. Mathematical model has been developed for determining the optimal order quantity, the optimal cycle time and optimal total inventory cost for both cases. Differential calculus is used for finding optimal solution. Numerical examples are given for both cases to validate the proposed model. Sensitivity analysis is carried out to analyze the effect of changes in the optimal solution with respect to change in various parameters.
Magnitude of Subclinical Hypothyroidism
R.P. Kudyar
JK Science : Journal of Medical Education & Research , 2001,
Abstract: Not Available
Renal pathology in working dogs in the South African National Defence Force : research communication
R.P. Short
Journal of the South African Veterinary Association , 2012, DOI: 10.4102/jsava.v70i4.787
Abstract: Urine analysis, serumbiochemical profile and a cortical wedge biopsy for histopathological examination was performed on 42 South African National Defence Force (SANDF) dogs from around the country. The only significant finding on urine analysis and serum biochemistry was a relatively large number (16/42) of dogs with elevated serum inorganic phosphate levels. Histopathology revealed that only 9 of the animals had normal kidneys reflected in the wedge biopsy material, with over 50%of them showing signs of glomerular pathology (primarily mesangioproliferative glomerulonephritis). Other conditions detected histopathologically were haemosiderosis (47 % of animals), focal nephrosis (2.4 %), membranoproliferative glomerulonephritis (2.4 %), focal interstitial nephritis (4.7 %) and acute tubular nephrosis (4.7 %). The lesions observed were of limited distribution and extent; this histopathological finding may account for the absence of significant abnormalities on urine analysis or serum biochemistry profiles. It appears from these results that a large percentage of the SANDF population would be expected to have mild renal lesions, but that these lesions are not severe enough to lead to clinical signs. The findings of this study are similar to those of randomly selected populations of non-military dogs performed in other areas of the world, which also demonstrated an unexpectedly high incidence of histopathological renal pathology in dogs considered healthy. These lesions may well, however, play a role in later life, and it is recommended that military veterinarians maintain an index of suspicion for renal disease, particularly glomerular disease. The aetiology of the histopathological lesions is unknown.
J. van der Stock, Printing images in Antwerp. The introduction of printmaking in a city. Fifteenth century to 1585
R.P. Fagel
BMGN : Low Countries Historical Review , 2000,
Abstract:
W. Thomas, In de klauwen van de Inquisitie. Europese protestanten in Spanje, 1517-1648
R.P. Fagel
BMGN : Low Countries Historical Review , 2004,
Abstract:
W. Thomas, R.A. Verdonk, Encuentros en Flandes. Relaciones e intercambios hispanoflamencos a inicios de la Edad Moderna
R.P. Fagel
BMGN : Low Countries Historical Review , 2002,
Abstract:
The control of deliberate waiting strategies in a stop-signal task
Sylwan R.P.
Brazilian Journal of Medical and Biological Research , 2004,
Abstract: To inhibit an ongoing flow of thoughts or actions has been largely considered to be a crucial executive function, and the stop-signal paradigm makes inhibitory control measurable. Stop-signal tasks usually combine two concurrent tasks, i.e., manual responses to a primary task (go-task) are occasionally countermanded by a stimulus which signals participants to inhibit their response in that trial (stop-task). Participants are always instructed not to wait for the stop-signal, since waiting strategies cause the response times to be unstable, invalidating the data. The aim of the present study was to experimentally control the strategies of waiting deliberately for the stop-signal in a stop-task by means of an algorithm that measured the variation in the reaction times to go-stimuli on-line, and displayed a warning legend urging participants to be faster when their reaction times were more than two standard deviations of the mean. Thirty-four university students performed a stop-task with go- and stop-stimuli, both of which were delivered in the visual modality and were lateralized within the visual field. The participants were divided into two groups (group A, without the algorithm, vs group B, with the algorithm). Group B exhibited lower variability of reaction times to go-stimuli, whereas no significant between-group differences were found in any of the measures of inhibitory control, showing that the algorithm succeeded in controlling the deliberate waiting strategies. Differences between deliberate and unintentional waiting strategies, and anxiety as a probable factor responsible for individual differences in deliberate waiting behavior, are discussed.
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