scholarly journals Development of a laboratory monitoring system for elastic waves transmitted through sand under dry and nearly saturated conditions

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Masayuki Nakayama ◽  
Hironori Kawakata ◽  
Shiro Hirano ◽  
Issei Doi
Keyword(s):  
Elastic Waves ◽  
Laboratory Experiments ◽  
Water Saturation ◽  
Spectral Amplitude ◽  
Wave Source ◽  
Content Change ◽  
Transmitted Waves ◽  
The Difference ◽  
Seismic Measurements ◽  
Water Content Change

AbstractLaboratory experiments with seismic measurements have the potential to be highly useful for understanding the physical process of water-induced landslides, and fundamental experiments are helpful for the appropriate interpretation of recorded seismograms. We developed a laboratory measurement system to investigate the relationships between wave propagation and water saturation in sand. We considered that the wavelength should be comparable to or sufficiently shorter than the sensing intervals. Furthermore, we embedded a wave source that can repeatedly emit an arbitrary and identical signal in an octave frequency band under both dry and nearly saturated conditions. We measured the transmitted waves by embedded accelerometers over 24 h under dry and nearly saturated conditions. The difference in the slowness between the two conditions was one-thousand-fold larger than the fluctuations in slowness over 24 h for each condition. Also, the difference in amplitude between the two conditions was about double the fluctuations in amplitude over 24 h for each condition. These results suggested that our system can monitor the water content change in sand via the change in spectral amplitude and phase slowness.

Observation and Experimentation

2018 ◽  
Author(s):  
Massimiliano Di Ventra
Keyword(s):  
Laboratory Experiments ◽  
The Difference

This chapter expands on the previous one on the role of experiments in Science. It explains the difference between observations of phenomena and controlled laboratory experiments.

Male-biased sex ratio in Argulus canadensis Wilson, 1916 (Crustacea: Branchiura) ectoparasitic on sticklebacks

1989 ◽  
Vol 67 (8) ◽  
pp. 2078-2080 ◽  
Author(s):  
Robert Poulin ◽  
Gerard J. FitzGerald
Keyword(s):  
Salt Marsh ◽  
Sex Ratio ◽  
Laboratory Experiments ◽  
Fish Predation ◽  
Reproductive Behaviour ◽  
Egg Deposition ◽  
Alternative Hypotheses ◽  
Biased Sex Ratio ◽  
The Difference ◽  
Fish Hosts

Females of the ectoparasitic crustacean Argulus canadensis must leave their fish hosts at least temporarily to deposit their eggs on the substrate. To test the hypothesis that this difference in reproductive behaviour between the two sexes could result in male-biased sex ratios on their stickleback hosts, we sampled sticklebacks in tide pools of a Quebec salt marsh from early July to early September 1986. During this period, fish harboured significantly more male than female A. canadensis. Laboratory experiments were done to test two alternative hypotheses offered to explain this biased sex ratio. The first hypothesis was that male A. canadensis were more successful than females in attacking their stickleback hosts; however, we found no differences in attack success on their hosts between the two parasite sexes. The second hypothesis was that sticklebacks ate more female than male A. canadensis. Although males were less vulnerable to fish predation than females, the difference was not significant. We conclude that sexual differences in reproductive behaviour, i.e., egg deposition behaviour of females, can account for the male-biased sex ratio of A. canadensis on sticklebacks.

scholarly journals Observed Long-term Water Content Change in Concrete Track Roadbed by Rainfall

2015 ◽  
Vol 14 (4) ◽  
pp. 35-43
Author(s):  
Chanyong Choi ◽  
Hunki Kim ◽  
Sangbeom Yang ◽  
KiYoung Eum
Keyword(s):  
Water Content ◽  
Content Change ◽  
Water Content Change

scholarly journals Liquid-liquid phase separation in particles containing secondary organic material free of inorganic salts

2017 ◽  
Author(s):  
Mijung Song ◽  
Pengfei Liu ◽  
Scot T. Martin ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Organic Material ◽  
Water Saturation ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Photo Oxidation ◽  
Condensation Nucleation ◽  
The Difference ◽  
Liquid Liquid Phase Separation

Abstract. Particles containing secondary organic material (SOM) are ubiquitous in the atmosphere and play a role in climate and air quality. Recently, research has shown that liquid-liquid phase separation (LLPS) occurs at high relative humidities (RH) (greater than ~ 95 %) in α-pinene-derived SOM particles free of inorganic salts while LLPS does not occur in isoprene-derived SOM particles free of inorganic salts. We expand on these findings by investigating LLPS in SOM particles free of inorganic salts produced from ozonolysis of β-caryophyllene, ozonolysis of limonene, and photo-oxidation of toluene. LLPS was observed at greater than ~ 95 % RH in the biogenic SOM particles derived from β-caryophyllene and limonene while LLPS was not observed in the anthropogenic SOM particles derived from toluene at 290 ± 1 K. This work combined with the earlier work on LLPS in SOM particles free of inorganic salts suggests that the occurrence of LLPS in SOM particles free of inorganic salts is related to the average oxygen-to-carbon elemental ratio (O : C) of the organic material. When the average O : C is between 0.25 and 0.60, LLPS was observed, but when the average O : C was between 0.52 and 1.3, LLPS was not observed. These results help explain the difference between the hygroscopic parameter k of SOM particles measured above and below water saturation in the laboratory and field, and have implications for predicting the cloud condensation nucleation properties of SOM particles.

scholarly journals The Formation of Brine Drainage Features in Young Sea Ice

1975 ◽  
Vol 14 (70) ◽  
pp. 137-154 ◽  
Author(s):  
Lars Ingolf Eide ◽  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Salt Water ◽  
Pressure Head ◽  
Drainage Channels ◽  
The Difference ◽  
Thin Plastic ◽  
Ice Water ◽  
Brine Channel

Laboratory experiments on the growth of sea ice in a very thin plastic tank filled with salt water, cooled from above and insulated with thermopane, clearly show the formation and development of brine drainage channels. The sea-water freezing cell is 0.3 cm thick by 35 cm wide by 50 cm deep; the thermopane insulation permits the ice interior to be photographed. Experimentally, we observe that vertical channels with diameters of 1 to 3 mm and associated smaller feeder channels extend throughout the ice sheet. Close examination of the brine channels show that their diameter at the ice-water interface is much narrower than higher up in the ice, so that the channel has a “neck” at the interface. Further, oscillations occur in the brine channels, in that brine flows out of the channel followed by a flow of sea-water up into the channel. Theoretically, a qualitative theory based on the difference in pressure head between the brine inside the ice and the sea-water provides a consistent explanation for the formation of the channels, and the onset of a convective instability explains the existence of the neck. Finally, an analysis based on the presence of the brine-channel neck provides an explanation for the observed oscillations.

scholarly journals Study on the Impacts of Capillary Number and Initial Water Saturation on the Residual Gas Distribution by NMR

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2714
Author(s):  
Tao Li ◽  
Ying Wang ◽  
Min Li ◽  
Jiahao Ji ◽  
Lin Chang ◽  
...  
Keyword(s):  
Capillary Number ◽  
Water Saturation ◽  
Transverse Relaxation Time ◽  
Spontaneous Imbibition ◽  
Trapping Efficiency ◽  
Gas Distribution ◽  
Initial Water ◽  
Capillary Trapping ◽  
Residual Gas ◽  
The Difference

The determination of microscopic residual gas distribution is beneficial for exploiting reservoirs to their maximum potential. In this work, both forced and spontaneous imbibition (waterflooding) experiments were performed on a high-pressure displacement experimental setup, which was integrated with nuclear magnetic resonance (NMR) to reveal the impacts of capillary number (Ca) and initial water saturation (Swi) on the residual gas distribution over four magnitudes of injection rates (Q = 0.001, 0.01, 0.1 and 1 mL/min), expressed as Ca (logCa = −8.68, −7.68, −6.68 and −5.68), and three different Swi (Swi = 0%, 39.34% and 62.98%). The NMR amplitude is dependent on pore volumes while the NMR transverse relaxation time (T2) spectrum reflects the characteristics of pore size distribution, which is determined based on a mercury injection (MI) experiment. Using this method, the residual gas distribution was quantified by comparing the T2 spectrum of the sample measured after imbibition with the sample fully saturated by brine before imbibition. The results showed that capillary trapping efficiency increased with increasing Swi, and above 90% of residual gas existed in pores larger than 1 μm in the spontaneous imbibition experiments. The residual gas was trapped in pores by different capillary trapping mechanisms under different Ca, leading to the difference of residual gas distribution. The flow channels were mainly composed of micropores (pore radius, r < 1 μm) and mesopores (r = 1–10 μm) at logCa = −8.68 and −7.68, while of mesopores and macropores (r > 10 μm) at logCa = −5.68. At both Swi= 0% and 39.34%, residual gas distribution in macropores significantly decreased while that in micropores slightly increased with logCa increasing to −6.68 and −5.68, respectively.

scholarly journals On the dynamics of starting plumes

2017 ◽  
Vol 833 ◽  
Author(s):  
N. Bhamidipati ◽  
Andrew W. Woods
Keyword(s):  
Laboratory Experiments ◽  
Added Mass ◽  
Rate Of Change ◽  
Small Scale ◽  
Maximum Height ◽  
Ambient Fluid ◽  
A Value ◽  
Proposed Model ◽  
The Difference ◽  
Reasonable Description

We explore the dynamics of starting plumes by analysis of a series of new small-scale laboratory experiments combined with a theoretical model for mass, momentum, and buoyancy conservation. We find that the head of the plume ascends with a speed which is approximately 0.6 times the characteristic speed of the fluid in the following steady plume, in accord with Turner (J. Fluid Mech., vol. 13 (03), 1962, pp. 356–368), and so the fluid released from the source eventually catches the head of the flow. On reaching the top of the plume it recirculates and mixes in the plume head. We estimate that approximately $0.61\pm 0.04$ of the total buoyancy released from the source accumulates in the plume head, with the remainder in the following steady plume. Using measurements of the volume of the head, we estimate that a fraction $0.16\pm 0.08$ of the volume of the head is entrained directly from the ambient, with the remainder of the fluid in the head being supplied by the following steady plume. These results imply that the buoyancy force exerted on the plume head plus the momentum flux supplied by the following plume exceeds the rate of change of momentum of the plume head even including the added mass of the plume head. We propose that the difference is associated with a drag force resulting from the displacement of ambient fluid around the plume head. Using our experimental data, we estimate that the drag coefficient $C_{d}$ has a value $4.2\pm 1.4$, with the range in values associated with the uncertainty in our estimate of entrainment of fluid directly into the plume head. As a test, the proposed model is shown to provide a reasonable description of a starting plume rising through a stratified environment in the region below the maximum height of rise of the associated steady plume, although, above this point, the shape of the plume head changes and the model breaks down.

scholarly journals The Formation of Brine Drainage Features in Young Sea Ice

1975 ◽  
Vol 14 (70) ◽  
pp. 137-154 ◽  
Author(s):  
Lars Ingolf Eide ◽  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Salt Water ◽  
Pressure Head ◽  
Drainage Channels ◽  
The Difference ◽  
Thin Plastic ◽  
Ice Water ◽  
Brine Channel

Laboratory experiments on the growth of sea ice in a very thin plastic tank filled with salt water, cooled from above and insulated with thermopane, clearly show the formation and development of brine drainage channels. The sea-water freezing cell is 0.3 cm thick by 35 cm wide by 50 cm deep; the thermopane insulation permits the ice interior to be photographed. Experimentally, we observe that vertical channels with diameters of 1 to 3 mm and associated smaller feeder channels extend throughout the ice sheet. Close examination of the brine channels show that their diameter at the ice-water interface is much narrower than higher up in the ice, so that the channel has a “neck” at the interface. Further, oscillations occur in the brine channels, in that brine flows out of the channel followed by a flow of sea-water up into the channel. Theoretically, a qualitative theory based on the difference in pressure head between the brine inside the ice and the sea-water provides a consistent explanation for the formation of the channels, and the onset of a convective instability explains the existence of the neck. Finally, an analysis based on the presence of the brine-channel neck provides an explanation for the observed oscillations.

scholarly journals Improved water saturation estimation in shaly sandstone through variable cementation factor

2021 ◽  
Author(s):  
Wan Zairani Wan Bakar ◽  
Ismail Mohd Saaid ◽  
Mohd Riduan Ahmad ◽  
Zulhelmi Amir ◽  
Nur Shuhadah Japperi ◽  
...  
Keyword(s):  
Water Saturation ◽  
Percentage Error ◽  
Saturation Model ◽  
Formation Factor ◽  
Archie’S Law ◽  
Straight Line ◽  
The Difference ◽  
Shaly Sandstone ◽  
Cementation Factor ◽  
Surface Conduction

AbstractEstimation of water saturation, Sw, in shaly sandstone is an intricate process. The surface conduction of clay minerals adds up to the electrolyte conduction in the pore spaces, thus generating high formation conductivity that overshadows the hydrocarbon effect. In each resistivity-based water saturation model, the key parameter is formation factor, F, which is typically derived from Archie’s Law. Referring to a log–log plot between formation factor and porosity, cementation factor reflects the slope of the straight line abiding Archie’s Law. In the case of shaly sandstone, derivation based on Archie’s Law in combination with Waxman–Smits equation leads to higher cementation factor, m*. In the shaly parts of the reservoir, high m* is counterbalanced by clay conductivity. Nonetheless, high m* used in clean parts increases Sw estimation. In this study, the variable cementation factor equation is introduced into the standard correlation of Sw versus Resistivity Index, RI, to develop a water saturation model with shaly sandstone parameters. Data retrieved from two fields that yielded mean arctangent absolute percentage error (MAAPE) were analysed to determine the difference between calculated and measured data within the 0.01–0.15 range for variable cementation factor method. The conventional method yielded maximum MAAPE at 0.46.

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