Absolute Negative Pressures Research Articles

INACTIVATION EFFECTS OF NEGATIVE PRESSURES BY A METAL BERTHELOT TECHNIQUE ON BACTERIA SOLUTIONS

Bacterial solutions are anticipated to be inactivated under absolute liquid negative pressures much lower in magnitude than positive ones. The pressures, however, have been hard to be produced by experiments because liquids form cavities easily through heterogeneous nucleation. To investigate the anticipation, solutions including two kinds of bacteria, namely Bacillus subtilis and Escherichia coli, were exposed to negative pressures repeatedly by a metal Berthelot tube which was designed newly. Then, numbers of colonies in bacteria which were cultured by a paper strip method and an agar dilute plate one were counted. Numbers of colonies which underwent negative pressures were less than those for non-treatment, and reduction rates of colonies increased with numbers of repetition.

Inactivation Effects of Negative Pressures by A Metal Berthelot Technique on Bacteria Solutions

Bacterial solutions are anticipated to be inactivated under absolute liquid negative pressures much lower in magnitude than positive ones. The pressures, however, have been hard to be produced by experiments because liquids form cavities easily through heterogeneous nucleation. To investigate the anticipation, solutions including two kinds of bacteria, namely Bacillus subtilis and Escherichia coli, were exposed to negative pressures repeatedly by a metal Berthelot tube which was designed newly. Then, numbers of colonies in bacteria which were cultured by a paper strip method and an agar dilute plate one were counted. Numbers of colonies which underwent negative pressures were less than those for non-treatment, and reduction rates of colonies increased with numbers of repetition. It was thought that inactivation effects of negative pressure on bacteria were due to destabilization of kinds of protein constituting the bacteria. Inactivation effects of negative pressure on bacteria will contribute to development of apparatus using ultrasound radiation by considering not only cavitation but also negative pressures without no chemical compound.

Disjoining pressure driven transpiration of water in a simulated tree

HypothesisTranspiration occurs in 100 m tall redwood trees where water is passively pulled against gravity requiring the evaporating liquid meniscus in stomata pores to be under absolute negative pressures of −10 atm or higher. Disjoining pressure can significantly reduce pressure at meniscus in nanopores due to strong surface-liquid molecular interaction. Hence, disjoining pressure should be able to solely govern the transpiration process. SimulationsExpression of disjoining pressure in a water film is first developed from prior experimental findings. The expression is then implemented in a commercial CFD solver and validated against experimental data for water wicking in nanochannels of height varying from 59 nm to 1 µm. Following the implementation, the transpiration process is simulated in a 3D domain comprising of a nanopore connected to a tube with ground-based water tank, thus mimicking the stomata-xylem-soil pathway in a 100 m tall tree. FindingsDisjoining pressure is found to induce absolute negative pressures as high as –23.5 atm at the evaporating meniscus and can also sustain high evaporation fluxes in nanopore before the meniscus completely dewets. This is the first report to integrate disjoining pressure into continuum simulations and study the transpiration process in a 100 m tall tree using such simulations.

Unloading induced absolute negative pore pressures in a low permeable clay shale

The stability analysis of underground excavations constructed in low-permeable rocks requires a comprehensive understanding of the short- and long-term pore pressure response around the excavation. This paper presents the results of a novel in-situ experiment, which was conducted in Opalinus Clay at the Mont Terri Underground Rock Laboratory, Switzerland. The primary aim of the project was to understand unloading-induced pore pressure changes in Opalinus Clay with a focus on the possibility of the development of absolute negative pore pressures. In this experiment, the pore pressure response was initiated by overcoring a small diameter pilot borehole equipped with a pressure transducer and a full-range tensiometer. The results of the experiment showed that the stress relief was accompanied by a noticeable pore pressure drop in the core. An absolute negative pore pressure of −755 kPa was measured. To replicate the pore pressure evolution during the in-situ experiment, a 3D hydro-mechanical-coupled finite element model was developed. It is shown that the magnitude of the pore pressure drop cannot be explained by the classical poroelasticity theory for fully saturated Opalinus Clay samples. Good agreement between the experimental data and numerical results can only be achieved when unloading induced desaturation is considered. Rapid unloading may cause pore water cavitation and desaturation, which significantly increases the pore fluid compressibility. Our considerations based on the nucleation theory suggest that during unloading the required conditions for pore water cavitation in pores larger than a critical value were met.

Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems.

This work highlights unexpected, not so well known responses of ionic liquids and ionic liquid-containing systems, which are reported in a collective manner, as a short review. Examples include: (i) Minima in the temperature dependence of the isobaric thermal expansion coefficient of some ILs; (ii) Viscosity Minima in binary mixtures of IL + Molecular solvents; (iii) Anomalies in the surface tension within a family of ILs; (iv) The constancy among IL substitution of Cp/Vm at and around room temperature; (v) ILs as glass forming liquids; (vi) Alternate odd-even side alkyl chain length effects; (vii) Absolute negative pressures in ILs and IL-containing systems; (viii) Reversed-charged ionic liquid pairs; (ix) LCST immiscibility behavior in IL + solvent systems.

On the development of an ultra-high-capacity tensiometer capable of measuring water tensions to 7 MPa

Tensiometers are increasingly used in geotechnical engineering to monitor pore-water tension in the field and to study the hydro-mechanical behaviour of unsaturated soils in the laboratory. Early tensiometers exhibited a relatively small measuring range, typically limited to a tension of 0·1 MPa, due to the breakdown of water tension inside the sensing unit at absolute negative pressures. This limitation was subsequently overcome by the design of high-capacity tensiometers (HCTs), which enabled the measurement of considerably larger pore-water tensions. According to the literature, the highest value of water tension ever recorded by an HCT is 2·6 MPa. In the present work, this value is almost tripled by designing a novel ultra-high-capacity tensiometer (UHCT) capable of recording water tensions up to 7·3 MPa. This is achieved by replacing the traditional ceramic interface with a nanoporous glass (typically employed by physicists for the study of confined liquids), which has never been used before in the manufacture of tensiometers. The maximum attainable tension has been determined using tests where the UHCT measurement was progressively increased by vaporising water from the glass interface until the occurrence of tension breakdown (often referred to as ‘heterogeneous cavitation’ or ‘tensiometer cavitation’). The increased measuring range and the potentially larger measuring stability of the proposed UHCT will contribute to enhance laboratory testing of soils at high suctions and long-term monitoring of earth structures.

Negative Pressure Regimes in Ionic Liquids: Structure and Interactions in Stretched Liquids as Probed by NMR

Condensed matter - solids or liquids, but not gases - might be deeply, homogeneously stretched to absolute negative pressures (metastable regimes of isotropic tension). For instance, we were able to stretch macroscopically-sized liquid solutions down to p ~ - 35 MPa,[1] a value which still constitutes a world record for large volume liquid samples. Up to now, the absolute record for neat liquids is hold for liquid water in microscopic porous crevices of natural rocks, p ~ -140 MPa. There are several strategies to force a liquid entering into negative pressure regimes. The most common one is the Berthelot method.[2] Negative pressures can be either directly measured - via a highly elaborated Bourdon-Berthelot combination methodology[3,4] or safely, though approximately, estimated through the liquid’s isochoric thermal-pressure coefficient, g v = a p/k T. In this work, a broad pallete of macroscopically sized samples of ionic liquids was used, in which tensions of about -100 MPa were obtained before cavitation would occur. This value constitutes a new record for large samples. The underlying success for achieving such great absolute negative pressures in ionic liquids as compared to other liquids seems to be the best combination of (i) their negligible vapour pressure and (ii) their generally high viscosity. Good adhesion (wettability) to the container’s walls (in this case Pyrex glass) is a paramount, minimum requirement. For the first time, NMR studies have been performed on ionic liquids under homogeneous tension. Due to potential hazard issues related to the protection/safety of the NMR instrumentation, negative pressures beyond the value of – 20 MPa were avoided. Upon entering into these metastable regimes of negative pressure, it was possible to observe a sharp increase in the ions self-diffusion coefficients as compared to the equilibrium saturated liquid conditions at the same temperatures. MD simulations have been performed to gain insights into the ILs structure and interactions under these deep metastable conditions.

Negative Pressures and the First Water Siphon Taller than 10.33 Meters.

A siphon is a device that is used to drain a container, with water rising inside a hose in the form of an inverted U and then going down towards a discharge point placed below the initial water level. The siphon is the first of a number of inventions of the ancients documented about 2.000 years ago by Hero of Alexandria in his treatise Pneumatics, and although the explanation given by Hero was essentially correct, there is nowadays a controversy about the underlying mechanism that explains the working of this device. Discussions concerning the physics of a siphon usually refer to concepts like absolute negative pressures, the strength of liquid’s cohesion and the possibility of a siphon working in vacuum or in the presence of bubbles. Torricelli understood the working principle of the barometer and the impossibility of pumping water out of wells deeper than 10.33 m. Following Torricelli’s ideas it would also not be possible to build a siphon that drives pure water to ascend higher than 10.33 m. In this work, we report the first siphon that drives water (with surfactant) to ascend higher than the Torricellian limit. Motivated by the rising of sap in trees, we built a 15.4 m siphon that shows that absolute negative pressures are not prohibited, that cohesion plays an important role in transmitting forces through a fluid, and that surfactants can help to the transport of water in a metastable regime of negative pressures.

Negative pressure characteristics of an evaporating meniscus at nanoscale.

This study aims at understanding the characteristics of negative liquid pressures at the nanoscale using molecular dynamics simulation. A nano-meniscus is formed by placing liquid argon on a platinum wall between two nano-channels filled with the same liquid. Evaporation is simulated in the meniscus by increasing the temperature of the platinum wall for two different cases. Non-evaporating films are obtained at the center of the meniscus. The liquid film in the non-evaporating and adjacent regions is found to be under high absolute negative pressures. Cavitation cannot occur in these regions as the capillary height is smaller than the critical cavitation radius. Factors which determine the critical film thickness for rupture are discussed. Thus, high negative liquid pressures can be stable at the nanoscale, and utilized to create passive pumping devices as well as significantly enhance heat transfer rates.

The “Hidden” Phase Diagram of Water + 3-Methylpyridine at Large Absolute Negative Pressures

Liquid−liquid (L−L) phase splitting in mixtures of water (H/D) + 3-methylpyridine (3-MP) at the limit of pure H2O as solvent and under high tension are reported for the first time. The phase diagram is thus encountered at large absolute negative pressure regimes. To the best of the authors' knowledge, these studies constitute the first to report phase transitions in nonpolymeric fluid mixtures at negative pressures, and the values of tension achieved (≈−350 bar) constitute a record for macroscopically sized samples. The overall behavior of mixtures of water (H/D) + 3-MP is successfully interpreted by using a simple gE-model. It is clearly shown that there is an intimate relation between pressures and the isotopic content of the solvent, and, thus, the latter can act as a thermodynamic variable. At critical concentrations, while mixtures of D2O + 3-MP always present phase separation irrespective of the applied pressure, when the solvent is pure H2O a miscibility window with the size of 1600 bar emerges. Th...

Measuring the Properties of Liquids and Liquid Mixtures at Absolute Negative Pressures

AbstractFor Abstract see ChemInform Abstract in Full Text.

Correction to "Achieving Absolute Negative Pressures in Liquids: Precipitation Phenomena in Solution"

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTCorrection to "Achieving Absolute Negative Pressures in Liquids: Precipitation Phenomena in Solution"Cite this: J. Chem. Educ. 2002, 79, 10, 1203Publication Date (Web):October 1, 2002Publication History Received3 August 2009Published online1 October 2002Published inissue 1 October 2002https://doi.org/10.1021/ed079p1203RIGHTS & PERMISSIONSArticle Views65Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (292 KB) Get e-Alerts Get e-Alerts

Achieving Absolute Negative Pressures in Liquids: Precipitation Phenomena in Solution

A relatively simple and inexpensive experiment to achieve absolute negative pressures in liquids is reported. The liquid is a 1.80% (w/w) solution of polystyrene (Mw = 25,000) in acetone. A detailed description of the experiment is followed by photographs, one of which shows a phase transition occurring at negative pressure. By repeating the experiment at different initial volume ratios of liquid to gas, several phase transition points (cloud points) at distinct negative pressures are determined. For each run, the achieved negative pressure is estimated using the isochoric thermal pressure coefficient γV. To test the reliability of the experimental data, they are compared with data obtained in the positive-pressure region using a different, more precise technique. The two sets of points match reasonably well.

Metastable critical lines in (acetone + polystyrene) solutions and the continuity of solvent-quality states

Double critical behavior of two distinct types was found in (acetone+polystyrene) liquid solutions. A quasi-monodisperse polystyrene of Mw∼16600 in perprotio-acetone presented a T–p extremum in the critical locus at low-temperature and high-pressure and a metastable p–T one at a higher temperature and a lower (and negative) pressure. The first case corresponds to a pressure-double critical point (DCP), while the latter is a metastable temperature-DCP. At the p-DCP one expects a change in the sign of the excess volume as pressure is varied, and at the T-DCP neighboring region a change in the sign of the excess enthalpy should occur with temperature change. A Berthelot-type method was used to achieve experimental absolute negative pressures of the order of −60 bar. To the best of the authors' knowledge, this constitutes the first experimental observation of a polymer solution with two types of double critical points with one penetrating the metastable region of negative pressures. A review of the pertinent literature suggests that acetone changes by virtue of applied pressure from a “non-solvent” to a “poor-solvent” and finally to a “θ-solvent” for polystyrene.

Water and Gallium at Absolute Negative Pressures. Loci of Maximum Density and of Melting

Several physical properties of liquids as well as those of the coexistence between liquid and solid can be determined at absolute negative pressures. Examples for this include thermal pressure coefficients, loci of temperature of maximum density, melting lines, speed of propagation of low-intensity sound waves, and (p, T, x) conditions of occurrence of liquid/liquid phase separation. Three model temperature-pressure cycles, which allow for the measurement of temperature-pressure conditions of the occurrence of maxima of liquid density. negatively sloped fusion lines, and the upper critical solution temperature (UCST) of liquid solutions in these metastable regimes are described. A new apparatus for measuring negative pressures was developed. The temperature and pressure are determined within an uncertainty of ±0.05°C and ±5 bar, respectively. Water and heavy water have been used as testing systems with respect to the location of their temperatures of maximum density (TMD) loci. Empirical equations of state whose parameters have been fitted to experimental data located in the normal positive pressure region have proven to extrapolate well to the negative pressure regime. Furthermore, an attempt was made to use SAFT in order to provide a more theoretically founded framework. Preliminary results for gallium have shown that a TMD exists 45 K inside the supercooled regime, and that the continuation of its melting line down to -80 bar evolves with a slope of -515 ± 25 bar.K -1 .

Long-term xylem pressure measurements in the liana Tetrastigma voinierianum by means of the xylem pressure probe

Diurnal changes of xylem pressure in the liana Tetrastigma voinierianum have been measured under greenhouse conditions by means of the recently developed xylem pressure probe. During the early morning hours, tensions in the vessels developed more or less rapidly with time, depending on light intensity. On sunny days, absolute negative pressures down to about -0.4 MPa (atmospheric = 0.1 MPa) were recorded around noon in petiolar or stem xylem vessels, whereas on rainy or cloudy days the xylem pressure remained in the positive sub-atmospheric or slightly negative pressure range. Towards the evening the tension in the vessels always decreased, i.e. the xylem pressure shifted to about atmospheric, or even above-atmospheric, values during the night. Simultaneous xylem pressure recordings at heights of 1 and 5 m frequently yielded either no gradient in tension at all, or far less than expected from the Cohesion Theory. Occasionally, tension gradients were even opposite to those predicted by this theory. Stem-toleaves pressure gradients in accord with the Cohesion Theory were recorded only when tension had been developed during sunny days in the upper branches of the liana, because increases in tension were not immediately propagated to the xylem of the leaves at ground level, as would be expected from a strictly coupled hydraulic system. Parallel recordings of the “xylem tension” using the pressure chamber yielded rather variable values ranging from 0.1 to 1 MPa; diurnal pressure changes could not be detected at all. The data are discussed on the basis of the equation for the chemical activity of water. They strongly suggest that the xylem tension induced by transpiration is not the sole force for water ascent. Other forces, such as osmotic pressure or convectional and interfacial forces, which to a remarkable extent have already been postulated for decades, seem to be equally important.

Model Simulation of Oil Hydraulic Systems Controlled by PWM Using 3-Way Ball Valve.

Although suitable for microcomputer technology, PWM control applied to oil hydraulic systems has one defect-unavoidable pulsation. In order to achieve a satisfactory design for such systems, as well as pulsation-reducing devices, a theoretical tool which can properly simulate their performances is essential. The present paper offers an improved simulation method for an oil hydraulic system with a 3-way ball valve driven by PWM. The present theoretical model has the following features which are rarely found in previous models : (1) adequate estimation of the PWM valve characteristics based on measurement, (2) consideration of wave propagation in channels connecting elements, (3) an ordinary power source model consisting of a pump and a relief valve. Agreements between numerical predictions and experimental results are satisfactory. The simulation has also clarified that absolute negative pressures and consequent cavitation bubbles can emerge in control lines when the valve drain port is exposed to the atmosphere.

Research on wave phenomena in hydraulic lines. 17th Report. Column separation with tesnile waves.

The present report deals with an investigation of tensile stress waves in oil. Experimantally generated pressure pu1ses below absolute zero turn out to propagate through an oil column exactly as the ordinary wave theory predicts, which verifies the reality of tensile stress waves. Absolute negative pressures after the separation cavity collapses, which have been theoretically predicted under the assumption that gas is not released in an oil column during the separation, are also confirmed for the first time. However the measured pressure wave shapes do not agree with the theoretical predictions in this case. Considerations of these results lead to the hypothesis that oil loaded with a tensile stress wave ruptures, depending on the duration and amplitude of the absolute negative pressure and also on the defects in oil constitution.

Rupture of an oil column under sudden tensile stress.

In the previous paper' the study of pressure waves in oil column separation led to the idea that an oil column should rupture when it is exposed to sudden tensile stress. The present paper subsequently deals with clarifying the idea of 'rupture'. In order to give evidence to the hypothesis, oil behavior in an acrylic tube during column separation is observed with a video camera and a photosensor: cavities are confirmed to emerge and disappear immediately after the reunion of separated columns. Theoretical discussion is held on a minute bubble with surface tension to see if it can consistently explain the ruptures and absolute negative pressures an oil column exhibits. In conclusion, the picture of oil rupture and cavitation is as follows: oil continuum yields to an excessive tensile force as metal does, then splits and produces a vacuum chasm into which resolved gas spreads from surrounding oil, which results in cavitation bubbles.