998 resultados para Vehicle Stability.


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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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A Knudsen flow reactor has been used to quantify functional groups on the surface of seven different types of combustion particle samples: 3 amorphous carbons (FS 101, Printex 60, FW 2), 2 flame soots (hexane soot generated from a rich and a lean diffusion flame), and 2 Diesel particles (SRM 2975, Diesel soot recovered from a Diesel particulate filter). The technique is based on a heterogeneous titration reaction between a probe gas and a specific functional group on the particle surface. Six probe gases have been selected for the quantification of important functional groups: N(CH3)3 for the titration of acidic sites, NH2OH for carbonyl functions of aldehydes and ketones, CF3COOH and HCl for basic sites of different strength, O3 and NO2 for oxidizable groups. The limit of detection was generally well below 1% of a formal monolayer of adsorbed probe gas. Results obtained with N(CH3)3 were higher for the FW 2 amorphous carbon (post-oxidized sample, according to the manufacturer) and the Diesel particles (between 5.2·10 13 and 5.8·10 13 molecule/cm2), indicating a higher state of oxidation than for the other samples (between 1.3·10 12 and 3.7·10 12 molecule/cm2). The ratio of uptakes of CF3COOH and HCl inferred the presence of basic oxides on the particle surface, owing to the larger stability of the acetate compared to the chloride counter ion in the resulting pyrylium salt. The reactivity of the FS 101 amorphous carbon (3.7·10 15 molecule/cm2) and the hexane flame soot (between 1.9·10 15 and 2.7·10 15 molecule/cm2) towards O3 was very high, indicating the presence of a huge amount of oxidizable or reduced groups on the surface of these samples. Besides the quantification of surface functional groups, the kinetics of reactions between particles and probe gases has also been studied. The uptake coefficient γ0 was roughly correlated with the amount of probe gas taken up by the samples. Indeed, the presence of a high density of functional groups led to fast uptake of the probe gas. These different findings indicate that the particle surface appeared multi-functional, with the simultaneous presence of antagonistic functional groups which do not undergo internal chemical reactions, such as acid-base neutralization. Results also point to important differences in the surface reactivity of the samples, depending on the combustion conditions. The relative distribution of the surface functional groups may be a useful indicator for the state of oxidation and the reactivity of the particle surface.

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BACKGROUND: Complex foot and ankle fractures, such as calcaneum fractures or Lisfranc dislocations, are often associated with a poor outcome, especially in terms of gait capacity. Indeed, degenerative changes often lead to chronic pain and chronic functional limitations. Prescription footwear represents an important therapeutic tool during the rehabilitation process. Local Dynamic Stability (LDS) is the ability of locomotor system to maintain continuous walking by accommodating small perturbations that occur naturally during walking. Because it reflects the degree of control over the gait, LDS has been advocated as a relevant indicator for evaluating different conditions and pathologies. The aim of this study was to analyze changes in LDS induced by orthopaedic shoes in patients with persistent foot and ankle injuries. We hypothesised that footwear adaptation might help patients to improve gait control, which could lead to higher LDS: METHODS: Twenty-five middle-aged inpatients (5 females, 20 males) participated in the study. They were treated for chronic post-traumatic disabilities following ankle and/or foot fractures in a Swiss rehabilitation clinic. During their stay, included inpatients received orthopaedic shoes with custom-made orthoses (insoles). They performed two 30s walking trials with standard shoes and two 30s trials with orthopaedic shoes. A triaxial motion sensor recorded 3D accelerations at the lower back level. LDS was assessed by computing divergence exponents in the acceleration signals (maximal Lyapunov exponents). Pain was evaluated with Visual Analogue Scale (VAS). LDS and pain differences between the trials with standard shoes and the trials with orthopaedic shoes were assessed. RESULTS: Orthopaedic shoes significantly improved LDS in the three axes (medio-lateral: 10% relative change, paired t-test p < 0.001; vertical: 9%, p = 0.03; antero-posterior: 7%, p = 0.04). A significant decrease in pain level (VAS score -29%) was observed. CONCLUSIONS: Footwear adaptation led to pain relief and to improved foot & ankle proprioception. It is likely that that enhancement allows patients to better control foot placement. As a result, higher dynamic stability has been observed. LDS seems therefore a valuable index that could be used in early evaluation of footwear outcome in clinical settings.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

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Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.