scholarly journals A STUDY ON UPLIFT PRESSURES OF TSUNAMI ACTING ON CEILINGS OF WATER CHANNELS

2017 ◽  
pp. 17
Author(s):  
Tomoyuki Takabatake ◽  
Yukinobu Oda ◽  
Kazunori Ito ◽  
Takahide Honda
Keyword(s):  
Numerical Simulations ◽  
Water Surface ◽  
Water Channel ◽  
Water Channels ◽  
Industrial Facility ◽  
Uplift Pressure ◽  
Trapped Air ◽  
Vertical Barrier ◽  
Predictive Methods ◽  
Impulsive Pressure

When tsunami enters a water channel of an industrial facility, the water surface inside the channel rises and uplift pressures act on the ceiling if it is reached by the water surface. In this study, magnitudes and characteristics of this uplift pressure are investigated both experimentally and numerically. The results show that (1) the uplift pressure comprises an initial impulsive pressure and a following more slowly varying pressure; (2) trapped air reduces the impulsive pressure, and thus attaching a vertical barrier to the ceiling could act as a countermeasure; and (3) the impulsive pressure can be evaluated approximately with conventional predictive methods and by appropriate numerical simulations.

scholarly journals Investigation of Water Leakage of Metro Segments Caused by Metro Underpass Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xiao Liang ◽  
Taiyue Qi ◽  
Zhiyi Jin ◽  
Pengtao Chen ◽  
Bo Lei ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Water Channel ◽  
Field Measurements ◽  
Water Channels ◽  
Underground Water ◽  
Confined Water ◽  
Field Investigations ◽  
On Line ◽  
Subway Stations ◽  
Technical Measures

Water leaking into metro segments is related directly to the presence of underground water. However, to date, the underground confined water channels formed by metro underpass reinforcement structures have not been considered as causes of the problem. In the present study, based on field investigations and geological data, confined water is identified as the source of segment leakage on Line 5 of Hangzhou Metro in China. It is then hypothesized that the problem stems from an underground confined water channel formed under the reinforced structure of the subway. Numerical simulations predict a settlement difference of 8–10 mm between the reinforcement area and the weak strata, and field monitoring data show this difference to be 8.62 mm. This consistency between the numerical simulations and the field measurements verifies the hypothesis. Finally, given the causes of underground confined water channels, corresponding technical measures such as piecewise secondary grouting are proposed to cut them off and avoid metro-segment leakage. The present research results contribute to the causes of and the laws governing the metro-segment leakage that occurs at subway stations and other reinforced structures.

Radio and Electrical Measurements on Glacial Streams

1987 ◽  
Vol 33 (114) ◽  
pp. 239-242
Author(s):  
M. E. R. Walford
Keyword(s):  
Electrical Conductivity ◽  
Water Channel ◽  
Water System ◽  
Low Frequency ◽  
Water Channels ◽  
Radiative Loss ◽  
Radio Waves ◽  
Electrical Measurements ◽  
Water Conductivity ◽  
Glacier Surface

AbstractWe discuss the suggestion that small underwater transmitters might be used to illuminate the interior of major englacial water channels with radio waves. Once launched, the radio waves would naturally tend to be guided along the channels until attenuated by absorption and by radiative loss. Receivers placed within the channels or at the glacier surface could be used to detect the signals. They would provide valuable information about the connectivity of the water system. The electrical conductivity of the water is of crucial importance. A surface stream on Storglaciären, in Sweden, was found, using a low-frequency technique, to have a conductivity of approximately 4 × 10−4 S m−1. Although this is several hundred times higher than the conductivity of the surrounding glacier ice, the contrast is not sufficient to permit us simply to use electrical conductivity measurements to establish the connectivity of englacial water channels. However, the water conductivity is sufficiently small that, under favourable circumstances, radio signals should be detectable after travelling as much as a few hundred metres along an englacial water channel. In a preliminary field experiment, we demonstrated semi quantitatively that radio waves do indeed propagate as expected, at least in surface streams. We conclude that under-water radio transmitters could be of real practical value in the study of the englacial water system, provided that sufficiently robust devices can be constructed. In a subglacial channel, however, we expect the radio range would be much smaller, the environment much harsher, and the technique of less practical value.

Water transport across mammalian cell membranes

1996 ◽  
Vol 270 (1) ◽  
pp. C12-C30 ◽  
Author(s):  
A. S. Verkman ◽  
A. N. van Hoek ◽  
T. Ma ◽  
A. Frigeri ◽  
W. R. Skach ◽  
...  
Keyword(s):  
Water Transport ◽  
Cell Membranes ◽  
Water Channel ◽  
Water Channels ◽  
Channel Structure ◽  
Level Information ◽  
Selective Channel ◽  
Transcriptional Units ◽  
Measurement Strategies

This review summarizes recent progress in water-transporting mechanisms across cell membranes. Modern biophysical concepts of water transport and new measurement strategies are evaluated. A family of water-transporting proteins (water channels, aquaporins) has been identified, consisting of small hydrophobic proteins expressed widely in epithelial and nonepithelial tissues. The functional properties, genetics, and cellular distributions of these proteins are summarized. The majority of molecular-level information about water-transporting mechanisms comes from studies on CHIP28, a 28-kDa glycoprotein that forms tetramers in membranes; each monomer contains six putative helical domains surrounding a central aqueous pathway and functions independently as a water-selective channel. Only mutations in the vasopressin-sensitive water channel have been shown to cause human disease (non-X-linked congenital nephrogenic diabetes insipidus); the physiological significance of other water channels remains unproven. One mercurial-insensitive water channel has been identified, which has the unique feature of multiple overlapping transcriptional units. Systems for expression of water channel proteins are described, including Xenopus oocytes, mammalian and insect cells, and bacteria. Further work should be directed at elucidation of the role of water channels in normal physiology and disease, molecular analysis of regulatory mechanisms, and water channel structure determination at atomic resolution.

Progesterone inhibition of water permeability in Bufo arenarum oocytes and urinary bladder

1996 ◽  
Vol 270 (5) ◽  
pp. F880-F885 ◽  
Author(s):  
P. Ford ◽  
G. Amodeo ◽  
C. Capurro ◽  
C. Ibarra ◽  
R. Dorr ◽  
...  
Keyword(s):  
Urinary Bladder ◽  
Xenopus Laevis ◽  
Water Permeability ◽  
Water Channel ◽  
Water Channels ◽  
Toad Urinary Bladder ◽  
Osmotic Permeability ◽  
Bufo Arenarum ◽  
Mrna Extraction

The ovarian oocytes from Bufo arenarum (BAO) but not those from Xenopus laevis (XLO) would have water channels (WC). We now report that the injection of the mRNA from BAO into the oocytes from XLO increased their water osmotic permeability (Pi) (reduced by 0.3 mM HgCl2 and reversed by 5 mM beta-mercaptoethanol). A 30-min challenge with progesterone induced, 18 h later, a reduction of the mercury-sensitive fraction of Pf in the BAO (but not in XLO). The mRNA from BAO pretreated with progesterone lost its capacity to induce WC in the XLO, but the hormone did not affect the expression of the WC in XLO previously injected with the mRNA from BAO. Pf was also measured in urinary bladders of BAO. Eighteen hours after a challenge with progesterone, a reduction in the hydrosmotic response to oxytocin was observed. Finally, the mRNA from the urinary bladder of BAO was injected into XLO. An increase in Pf was observed. This was not the case if, before the mRNA extraction, the bladders were treated with progesterone. We conclude that the BAO WC share progesterone sensitivity with the oxytocin-regulated water channel present in the toad urinary bladder.

Design Considerations for Artificial Water Channel–Based Membranes

2018 ◽  
Vol 48 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Woochul Song ◽  
Chao Lang ◽  
Yue-xiao Shen ◽  
Manish Kumar
Keyword(s):  
Historical Perspective ◽  
Water Channel ◽  
Water Channels ◽  
Structure And Properties ◽  
High Permeability ◽  
Functional Elements ◽  
Design Considerations ◽  
Biological Water ◽  
Naturally Occurring ◽  
Artificial Water

Aquaporins (AQPs) are naturally occurring water channel proteins. They can facilitate water molecule translocation across cellular membranes with exceptional selectivity and high permeability that are unmatched in synthetic membrane systems. These unique properties of AQPs have led to their use as functional elements in membranes in recent years. However, the intricate nature of AQPs and concerns regarding their stability and processability have encouraged researchers to develop synthetic channels that mimic the structure and properties of AQPs and other biological water-conducting channels. These channels have been termed artificial water channels. This article reviews current progress and provides a historical perspective as well as an outlook toward developing scalable membranes based on artificial water channels.

Conformational dynamics and interfacial interactions of peptide-appended pillar[5]arene water channels in biomimetic membranes

2019 ◽  
Vol 21 (41) ◽  
pp. 22711-22721 ◽  
Author(s):  
Yong Liu ◽  
Harish Vashisth
Keyword(s):  
Water Purification ◽  
Conformational Dynamics ◽  
Water Channel ◽  
Water Channels ◽  
Interfacial Interactions ◽  
Biomimetic Membranes ◽  
Channel Proteins ◽  
Significant Potential ◽  
Biological Water ◽  
Artificial Water

Peptide appended pillar[5]arene (PAP) is an artificial water channel resembling biological water channel proteins, which has shown a significant potential for designing bioinspired water purification systems.

Theoretical Modelling of Free Falling Wedges Entering the Water Surface: Part I — Wedge Motions

2013 ◽  
Author(s):  
Jingbo Wang
Keyword(s):  
Numerical Simulations ◽  
Froude Number ◽  
Penetration Depth ◽  
Water Surface ◽  
Theoretical Models ◽  
Theoretical Modelling ◽  
Rapid Variation ◽  
Drag Coefficients ◽  
Free Falling ◽  
Theoretical Results

As the first of two companion papers, theoretical models are proposed to describe the motions of free falling wedges vertically entering the water surface at Froude numbers: 1 ≤ Fn < 9 (Here, the Froude number is defined as Fn=V0/gc0). The time evolutions of the penetration depth, the velocity and the acceleration are analyzed and expressed explicitly The maximum and average accelerations are predicted. The drag (slamming) coefficients are extensively studied. It is found that for the light wedge the transient drag coefficients have slow variation in the first half stage and rapid variation in the last half stage, and for the heavy wedge the transient drag coefficients vary slowly during the whole stage and can be treated as constant. The theoretical results are compared with numerical simulations by nonlinear BEM (Wang & Faltinsen (2010, 2013)), and good agreements are obtained.

Quantitation and topography of membrane proteins in highly water-permeable vesicles from ADH-stimulated toad bladder

1991 ◽  
Vol 261 (1) ◽  
pp. C143-C153 ◽  
Author(s):  
H. W. Harris ◽  
M. L. Zeidel ◽  
C. Hosselet
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayer ◽  
Apical Membrane ◽  
Water Channel ◽  
Protein S ◽  
Water Channels ◽  
Toad Bladder ◽  
Western Blots ◽  
Vesicle Protein

Antidiuretic hormone (ADH) stimulation of toad bladder granular cells rapidly increases the osmotic water permeability (Pf) of their apical membranes by insertion of highly selective water channels. Before ADH stimulation, these water channels are stored in large cytoplasmic vesicles called aggrephores. ADH causes aggrephores to fuse with the apical membrane. Termination of ADH stimulation results in prompt endocytosis of water channel-containing membranes via retrieval of these specialized regions of apical membrane. Protein components of the ADH water channel contained within these retrieved vesicles would be expected to be integral membrane protein(s) that span the vesicle's lipid bilayer to create narrow aqueous channels. Our previous work has identified proteins of 55 (actually a 55/53-kDa doublet), 17, 15, and 7 kDa as candidate ADH water channel components. We now have investigated these candidate ADH water channel proteins in purified retrieved vesicles. These vesicles do not contain a functional proton pump as assayed by Western blots of purified vesicle protein probed with anti-H(+)-ATPase antisera. Approximately 60% of vesicle protein is accounted for by three protein bands of 55, 53, and 46 kDa. Smaller contributions to vesicle protein are made by the 17- and 15-kDa proteins. Triton X-114-partitioning analysis shows that the 55, 53, 46, and 17 kDa are integral membrane proteins. Vectorial labeling analysis with two membrane-impermeant reagents shows that the 55-, 53-, and 46-kDa protein species span the lipid bilayer of these vesicles. Thus the 55-, 53-, and 46-kDa proteins possess characteristics expected for ADH water channel components. These data show that the 55- and 53- and perhaps the 46-, 17-, and 15-kDa proteins are likely components of aqueous transmembrane pores that constitute ADH water channels contained within these vesicles.

Experimental Study of Very Low Aspect Ratio Wings in Slender Bodies

2012 ◽  
Author(s):  
M. A. Arevalo-Campillos ◽  
S. Tuling ◽  
L. Parras ◽  
C. del Pino ◽  
L. Dala
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Numerical Simulations ◽  
Water Channel ◽  
Vortex Sheet ◽  
The Body ◽  
Low Aspect Ratio ◽  
Moderate Reynolds Number ◽  
Slender Bodies ◽  
Low Aspect Ratio Wings

The dynamics of very low aspect ratio wings (or strakes) vortices in slender bodies are complex due to the interaction of the shed vortex sheet and the body vortex. For missiles at supersonic speeds these interactions are not easily predicted using engineering level tools. To shed some new light onto this problem, an experimental study in a water channel for moderate Reynolds number (Re = 1000) was performed for a 19D body and strake configuration with strakes having a span to body diameter ratio of 1.25. Comparisons to numerical simulations in supersonic flow are also performed. Flow visualisation has been carried out to characterize the vortex dynamics at different angles of attack; these being 11°, 16°, 22° and 27°. The comparison between a slender body without strakes and the body-strake configuration has given some key indicators in relation to the vortex position of the core. Furthermore, unsteady wing-body interference has been observed at angles of attack above 20° for both experimental and numerical simulations. Consequently, the average position of the vortex core is located at larger distances from the missile in comparison to the body without strakes. The numerical simulations show good correlation with the experimental tests even though the dynamic convective interactions between the body vortex and strake vortex sheet are not predicted.

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