scholarly journals An equivalent method of jet impact loading from collapsing near-wall acoustic bubbles: A preliminary study

2021 ◽  
pp. 105760
Author(s):  
Xiang Lu ◽  
Chen Chen ◽  
Kai Dong ◽  
Zefa Li ◽  
Jiankang Chen
Author(s):  
Jaeha Lee ◽  
Goangseup Zi ◽  
Ilkeun Lee ◽  
Yoseok Jeong ◽  
Kyeongjin Kim ◽  
...  

Recently, there was a collision accident involving vehicle–concrete median barrier in South Korea, and unfortunately, passengers on the opposite direction road were killed by the flying broken pieces of concrete generated by the collision. Primarily after this accident, we felt the need for developing an improved concrete median barrier up to level of SB6 impact severity in order to minimize the amount of broken pieces of concrete and any possibility of traffic accident casualty under the impact loading of truck. Accordingly, in this study, several designs of concrete median barriers have been examined, and a preliminary study has been conducted for developing and verifying appropriate collision model. First, type of vehicle was selected based on impact analysis on rigid wall. Then, the effects of element size and other key parameters on the capacity of the concrete median barrier under impact were studied. It was found that the key parameters for controlling behaviors of the median barrier under impact loading were contact option, threshold value, and mesh and boundary conditions. Furthermore, as a parametric study, effect of geometry and amount of wire-mesh or steel rebar in concrete median barrier on impact resistances of median barrier for reducing the collision debris were investigated. The amount of volume loss after the collision of truck was compared for various reinforcement ratios.


2018 ◽  
Vol 12 (1) ◽  
pp. 112-123 ◽  
Author(s):  
Marina D’Antimo ◽  
Massimo Latour ◽  
Gianvittorio Rizzano ◽  
Jean-François Demonceau ◽  
Jean-Pierre Jaspart

Background:Recent catastrophic events have pointed out the need to ensure the integrity of structures under “exceptional” events. Since many years, the University of Liège is involved in different activities and projects related to the robustness assessment of structures. The robustness of a structure is the ability of the system to remain globally stable after events not directly accounted for in the design, like impact, fire or consequences of a human error, which should lead to a reasonable damage when compared to the original cause.Objective:The presented preliminary work reports the experimental campaign of different European projects (FREEDAM and ROBUSTIMPACT) carried out or currently ongoing, with the aim of understanding the behaviour of different joint typologies under impact loading protocol.Method:The experimental programmes have mainly regarded static and impact tests on steel joints by the means of a dropping mass using DIC (Digital Image Correlation) for the data acquisition.Conclusions:In the present paper, an overview on the design criteria adopted in the design of the experimental campaign, for the FREEDAM project, is given, and some earliest results are discussed.


Author(s):  
John H.L. Watson ◽  
John L. Swedo ◽  
R.W. Talley

A preliminary study of human mammary carcinoma on the ultrastructural level is reported for a metastatic, subcutaneous nodule, obtained as a surgical biopsy. The patient's tumor had responded favorably to a series of hormonal therapies, including androgens, estrogens, progestins, and corticoids for recurring nodules over eight years. The pertinent nodule was removed from the region of the gluteal maximus, two weeks following stilbestrol therapy. It was about 1.5 cms in diameter, and was located within the dermis. Pieces from it were fixed immediately in cold fixatives: phosphate buffered osmium tetroxide, glutaraldehyde, and paraformaldehyde. Embedment in each case was in Vestopal W. Contrasting was done with combinations of uranyl acetate and lead hydroxide.


Author(s):  
H.D. Geissinger ◽  
C.K. McDonald-Taylor

A new strain of mice, which had arisen by mutation from a dystrophic mouse colony was designated ‘mdx’, because the genetic defect, which manifests itself in brief periods of muscle destruction followed by episodes of muscle regeneration appears to be X-linked. Further studies of histopathological changes in muscle from ‘mdx’ mice at the light microscopic or electron microscopic levels have been published, but only one preliminary study has been on the tibialis anterior (TA) of ‘mdx’ mice less than four weeks old. Lesions in the ‘mdx’ mice vary between different muscles, and centronucleation of fibers in all muscles studied so far appears to be especially prominent in older mice. Lesions in young ‘mdx’ mice have not been studied extensively, and the results appear to be at variance with one another. The degenerative and regenerative aspects of the lesions in the TA of 23 to 26-day-old ‘mdx’ mice appear to vary quantitatively.


Author(s):  
J P Cassella ◽  
V Salih ◽  
T R Graham

Left ventricular assist systems are being developed for eventual long term or permanent implantation as an alternative to heart transplantation in patients unsuitable for or denied the transplant option. Evaluation of the effects of these devices upon normal physiology is required. A preliminary study was conducted to evaluate the morphology of aortic tissue from calves implanted with a pneumatic Left Ventricular Assist device-LVAD. Two 3 month old heifer calves (calf 1 and calf 2) were electively explanted after 128 days and 47 days respectively. Descending thoracic aortic tissue from both animals was removed immediately post mortem and placed into karnovsky’s fixative. The tissue was subsequently processed for transmission electron microscopy (TEM). Some aortic tissue was fixed in neutral buffered formalin and processed for routine light microscopy.


2021 ◽  
Author(s):  
Hicham Zaroual ◽  
El Mestafa El Hadrami ◽  
Romdhane Karoui

This study examines the feasibility of using front face fluorescence spectroscopy (FFFS) to authenticate 41 virgin olive oil (VOO) samples collected from 5 regions in Morocco during 2 consecutive crop seasons.


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