A simplified analytical method for predicting the critical velocity of vehicle impact on steel columns

2014 ◽  
Vol 92 ◽  
pp. 136-149 ◽  
Author(s):  
Haitham Al-Thairy ◽  
Y.C. Wang
2014 ◽  
Vol 566 ◽  
pp. 193-198
Author(s):  
Haitham A.B. Al-Thairy ◽  
Y.C. Wang

The main objective of this study is to develop a simplified analytical approach to predict the critical velocity of vehicle impact on steel columns. This method utilizes the energy balance principle with a quasi-static approximation of the steel column response. Results of ABAQUS numerical simulations of the dynamic impact response of axially loaded steel columns under vehicle impact are used to validate the proposed method. To account for the effect of vehicle impact, a simplified numerical vehicle model has been adopted using a spring-mass system with a bilinear spring load-deformation relationship. The validation results show good agreement between the analytical method results and the numerical results with the analytical results tending to be on the safe side.


1993 ◽  
Author(s):  
Douglas M. Ries ◽  
James A. Kirk ◽  
David P. Plant

Author(s):  
John A. Trotter

Hemoglobin is the specific protein of red blood cells. Those cells in which hemoglobin synthesis is initiated are the earliest cells that can presently be considered to be committed to erythropoiesis. In order to identify such early cells electron microscopically, we have made use of the peroxidatic activity of hemoglobin by reacting the marrow of erythropoietically stimulated guinea pigs with diaminobenzidine (DAB). The reaction product appeared as a diffuse and amorphous electron opacity throughout the cytoplasm of reactive cells. The detection of small density increases of such a diffuse nature required an analytical method more sensitive and reliable than the visual examination of micrographs. A procedure was therefore devised for the evaluation of micrographs (negatives) with a densitometer (Weston Photographic Analyzer).


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
K Miyagi ◽  
T Fujise ◽  
N Koga ◽  
K Wada ◽  
M Yano ◽  
...  

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