976 resultados para Contoured Moving Barrier-to-Vehicle Impact Tests.


Relevância:

100.00% 100.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Washington, D.C.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Federal Highway Administration, Safety Design Division, McLean, Va.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Federal Highway Administration, Office of Research, Development, and Technology, Washington, D.C.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Federal Highway Administration, Office of Safety and Traffic Operations Research and Development, McLean, Va.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Federal Highway Administration, Office of Safety and Traffic Operations Research and Development, McLean, Va.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Federal Highway Administration, Office of Research, Washington, D.C.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Washington, D.C.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Washington, D.C.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Gene-based tests of association are frequently applied to common SNPs (MAF>5%) as an alternative to single-marker tests. In this analysis we conduct a variety of simulation studies applied to five popular gene-based tests investigating general trends related to their performance in realistic situations. In particular, we focus on the impact of non-causal SNPs and a variety of LD structures on the behavior of these tests. Ultimately, we find that non-causal SNPs can significantly impact the power of all gene-based tests. On average, we find that the “noise” from 6–12 non-causal SNPs will cancel out the “signal” of one causal SNP across five popular gene-based tests. Furthermore, we find complex and differing behavior of the methods in the presence of LD within and between non-causal and causal SNPs. Ultimately, better approaches for a priori prioritization of potentially causal SNPs (e.g., predicting functionality of non-synonymous SNPs), application of these methods to sequenced or fully imputed datasets, and limited use of window-based methods for assigning inter-genic SNPs to genes will improve power. However, significant power loss from non-causal SNPs may remain unless alternative statistical approaches robust to the inclusion of non-causal SNPs are developed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The dynamic interaction of vehicles and bridges results in live loads being induced into bridges that are greater than the vehicle’s static weight. To limit this dynamic effect, the Iowa Department of Transportation (DOT) currently requires that permitted trucks slow to five miles per hour and span the roadway centerline when crossing bridges. However, this practice has other negative consequences such as the potential for crashes, impracticality for bridges with high traffic volumes, and higher fuel consumption. The main objective of this work was to provide information and guidance on the allowable speeds for permitted vehicles and loads on bridges .A field test program was implemented on five bridges (i.e., two steel girder bridges, two pre-stressed concrete girder bridges, and one concrete slab bridge) to investigate the dynamic response of bridges due to vehicle loadings. The important factors taken into account during the field tests included vehicle speed, entrance conditions, vehicle characteristics (i.e., empty dump truck, full dump truck, and semi-truck), and bridge geometric characteristics (i.e., long span and short span). Three entrance conditions were used: As-is and also Level 1 and Level 2, which simulated rough entrance conditions with a fabricated ramp placed 10 feet from the joint between the bridge end and approach slab and directly next to the joint, respectively. The researchers analyzed and utilized the field data to derive the dynamic impact factors (DIFs) for all gauges installed on each bridge under the different loading scenarios.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

An overview of the design and performance of geosynthetics in composite barrier systems for biopiles used to remediate hydrocarbon-contaminated soil at Casey Station, Antarctica, is presented. Seven instrumented biopiles were constructed over three field seasons. To minimize the risk of hydrocarbon migration to groundwater, composite barrier systems were used (each using different combinations of geosynthetic clay liners (GCLs), high density polyethylene (HDPE) geomembranes (GMB), and geotextiles (GTXs)). One biopile used a co-extruded geomembrane (HDPE with an ethylene vinyl alcohol (EVOH) core). The liner system was subject to a combination of coupled phenomena that could interact and affect the GMB-GCL composite barrier performance. The exposure conditions involved potential freeze-thaw cycling, hydration-desiccation cycles, cation exchange, direct and diffusive exposure to hydrocarbons. The effect of these phenomena was investigated by monitoring GCL and GMB sacrificial coupons. GCL coupons were placed between the main GCL component and the main geomembrane component of the composite liner and GMB coupons placed between the main GMB sheet and the GTX protection layer. Coupons were exhumed from the biopiles each year. The exhumed GCL field moisture content values ranged from 162% to 22%. After three (3) years in the field, GCL coupons that had undergone at least one hydration/desiccation cycle showed no significant change in swell index values or fluid loss values. The measured hydraulic conductivity of exhumed GCL coupons from Biopiles 1 and 2 (3 × 10-11 m s-1) was within the expected range and not significantly different from the values for virgin GCL. GMB coupons exhumed after three years from Biopiles 1 and 2 showed no significant change in oxidative induction time (OIT), melt flow index or tensile properties. Diffusion tests were performed as an index test for establishing the performance of the GMBs as a diffusive barrier to hydrocarbons, with permeation parameters for BTEX contaminants ranging from P g = 0.9-9.2 × 10-13 m2 s-1 for the exhumed GMB (with values depending on the contaminant and GMB). These values were similar to the parameters obtained for virgin GMBs and there was no significant change with field exposure, with GMBs appearing to be performing well.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper presents a detailed description of the influence of critical parameters that govern the vulnerability of columns under lateral impact loads. Numerical simulations are conducted by using the Finite Element program LS-DYNA, incorporating steel reinforcement, material models and strain rate effects. A simplified method based on impact pulse generated from full scale impact tests is used for impact reconstruction and effects of the various pulse loading parameters are investigated under low to medium velocity impacts. A constitutive material model which can simulate failures under tri-axial state of stresses is used for concrete. Confinement effects are also introduced to the numerical simulation and columns of Grade 30 to 50 concrete under pure axial loading are analysed in detail. This research confirmed that the vulnerability of the axially loaded columns can be mitigated by reducing the slenderness ratio and concrete grade, and by choosing the design option with a minimal amount of longitudinal steel. Additionally, it is evident that approximately a 50% increase in impact capacity can be gained for columns in medium rise buildings by enhancing the confinement effects alone. Results also indicated that the ductility as well as the mode of failure under impact can be changed with the volumetric ratio of lateral steel. Moreover, to increase the impact capacity of the vulnerable columns, a higher confining stress is required. The general provisions of current design codes do not sufficiently cover this aspect and hence this research will provide additional guidelines to overcome the inadequacies of code provisions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

International research has found that domestic violence is a significant barrier to accessing and sustaining work (Lloyd and Taluc 1999, 385; Browne et al. 1999, 398). In the Australian context, the Bureau of Crime Statistics and Research reports that between 6 and 9 per cent of Australian women aged 18 and over are physically assaulted each year and that more than half of all women in Australia experience sexual or physical violence across their adult lifetime. Such behaviour has been estimated to cost $8.1 billion, of which $4.4 billion is estimated to be borne by the victims themselves, $1.2 billion by the general community and smaller amounts by friends and family and various levels of government (Access Economics 2004). This assessment underestimates the costs of domestic violence in terms of the inability of those who have experienced domestic violence to move into and secure sustainable employment options. Despite these statistics there is a dearth of Australian research focussing on the link between domestic violence and its impact on long-term sustainable employment for those who have been subjected to such violence. This paper explores the issue of domestic violence and access to work opportunities. In so doing, it links the work of Gianakos (1999) and her Career Development theory with that of Bandura‘s (1989) Social Cognitive Career Theory to develop a framework which would provide a pathway to enable those who have suffered domestic violence to achieve sustainable employment and economic independence.