42 resultados para aicraft propulsion


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this research study was quantify the power, force of vertical impulse, jumping height and the relation of the power output during the execution of the layup in basketball, by variables associated to anthropometric data. The study was carried with seven basketball players, university students, male, from the Universidade Estadual Paulista Julio Mesquita Filho (Unesp) basketball team, from Bauru City. The players were an age of 20,7 ± 2,4 years old, body weight of 77,1 ± 9,4 kg, body fat of 14,7 ± 3,6%, lean mass of 65,5 ± 6,2 kg and height of 180,0 ± 5,0 cm. Each player did the ability of the layup three times, with a previous time to adapt. The kinetic and kinematic values was obtained from the data of a system that consists of photocells and a contact carpet from a system called JumpSystemâ (CEFISE), using after that equations of UVRM and impulse. The photocells was dispose to capture the previous run-up, as well the speedy in the time of two steps of the layup, and it was also synchronized with the contact carpet in the last step, to preserve the exactly time of the propulsion of jump. In this way, the values and the kinetic variables found was vV (2,94 ± 0,3 m's-1), vH (11,3 ± 3,4 m's-1), vI (11,8 ± 3,2 m's-1), time of contact (0,214 ± 0,2 s), angle of jump (15,9 ± 6,26 graus) and H (44,3 ± 8,9 cm). The variables and the kinematic values found was FimpV (974,9 ± 119,03 N, PP (3112,9 ± 633,9 W) and PM (1556,4 ± 316,9 W). To better understand the ability of layup in basketball, as the kinetic variables, kinematic variables and anthropometrics that determine the performance, the study did correlations between dV (H) with vV, vH, vI, angle, FimpV, PP e PM; FimpV, PP e PM com with the kinetic variables of vV, vH, vI, angle, and anthropometric variables of PC and height, and correlations of PP e PM with %G and MM. So, significant results was found between the correlations of dV with FimpV (R2 = 0,81)...

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The increasing number of space debris in operating regions around the earth constitutes a real threat to space missions. The goal of the research is to establish appropriate scientific-technological conditions to prevent the destruction and/or impracticability of spacecraft in imminent collision in these regions. A definitive solution to this problem has not yet been reached with the degree of precision that the dynamics of spatial objects (vehicle and debris) requires mainly due to the fact that collisions occur in chains and fragmentation of these objects in the space environment. This fact threatens the space missions on time and with no prospects for a solution in the near future. We present an optimization process in finding the initial conditions (CIC) to collisions, considering the symmetry of the distributions of maximum relative positions between spatial objects with respect to the spherical angles. For this, we used the equations of the dynamics on the Clohessy-Witshire, representing a limit of validation that is highly computationally costly. We simulate different maximum relative positions values of the corresponding initial conditions given in terms of spherical angles. Our results showed that there are symmetries that significantly reduce operating costs, such that the search of the CIC is advantageously carried out up to 4 times the initial processing routine. Knowledge of CIC allows the propulsion system operating vehicle implement evasive maneuvers before impending collisions with space debris.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hair ingested by licking during cat grooming can eventually coalesce into solid masses in cat gastrointestinal tract. It is believed that dietary fibre might reduce formation of these trichobezoars (hairballs). The effects of two insoluble fibre sources added to kibble diets were evaluated with respect to trichobezoar faecal excretion. Thirty-two cats and four diets were used in a randomised block design: a control diet without additional fibre, 10 % added sugarcane fibre, 20 % added sugarcane fibre or 10 % added cellulose. Animals were fed for 42 d and during three separate periods (days 15-17, 25-27 and 40-42), the cats were housed individually in metabolic cages and their faeces were totally collected. The faeces were evaluated and the trichobezoars were isolated and classified into small (<1 cm), medium (1·1-2 cm) or large (>2·1 cm). Means were evaluated by repeated measures ANOVA and contrasts (P < 0·05). Cats fed sugarcane fibre shown a linear reduction of small and medium trichobezoar excretion (number per cat per day; P = 0·004) as well as a reduction in trichobezoar mass excretion (mg per cat per day; P < 0·01). The control group showed increased faecal excretion of large trichobezoars (P = 0·003), which were not present in the high sugarcane fibre group (P < 0·006). No effect of cellulose was observed for any evaluated trait. Therefore, long fibres (sugarcane fibre) may cause greater peristaltic stimulation, increasing the propulsion of hair through the gut, but further research is needed to validate this mechanism. In conclusion, sugarcane fibre reduced faecal hairball elimination in cats, which may have clinical applications for the prevention of health problems related to trichobezoars.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Física - FEG

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Mecânica - FEG

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Mecânica - FEB

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this paper is to present a benefit-cost ranking of 127 civil transport aircraft; this ranking was determined considering a new data envelopment analysis (DEA) approach, called triple index, which combines three assessment methods: 1) standard frontier, 2) inverted index; 3) cross-multiplicative index. The analysis used the following inputs: a) market price; b) direct operating costs; and as outputs: a) payload, b) cruise speed; c) maximum rate of climb with a single engine. To ensure the homogeneity of the units, the aircrafts were divided according to the propulsion system (jet and turboprop) and size (regional, narrow-body and wide-body); they were also evaluated according to different ranges in order to identify the aircraft with the best cost-benefit relationship for each option.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Currently there are two car models that use electricity in their propulsion systems, the electric vehicle and the hybrid electric vehicle. The electric vehicles are classified as vehicles that use electric motors in their propulsion system and batteries as a power source, on the other hand, the hybrid vehicles are classified as vehicles that use both electric motors and internal combustion engines in their propulsion system, using both batteries and líquid fuels as a power source. The main goal of this work is to analyze the characteristics of electric and hybrid electric vehicles and demonstrate the unfeasibility of the electric vehicle in the current economic, political, energetic and environmental brazilian scenario, for this purpose it was realized a study about the current brazilian situation regarding to electricity generation, current conservation status of road network, lack of electrical infrastructure for charging batteries, national lithium reserves, environmental characteristics, tax incentives, economic scenario, oil market and political positioning related to the implantation of electric or hybrid electric fleets in nacional territory. The operational characteristics analysis of electric and hybrid electric vehicles in this current scenario leads to the conclusion that currently a growth of electric vehicles fleets on a national scale is totally impractical in the Brazil, Thus, the introduction of green vehicles probably will occur primarily with hybrid electric models, motivated mainly due the bigger autonomy of this models compared to electric models, lower cost of hybrid electric models compared to electric models, factors related to the lack of recharging infrastructure and also factors related to political positioning