Physical Properties Of Liquid Research Articles

Anomalies and Local Structure of Liquid Water from Boiling to the Supercooled Regime as Predicted by the Many-Body MB-pol Model.

For the past 50 years, researchers have sought molecular models that can accurately reproduce water's microscopic structure and thermophysical properties across broad ranges of its complex phase diagram. Herein, molecular dynamics simulations with the many-body MB-pol model are performed to monitor the thermodynamic response functions and local structure of liquid water from the boiling point down to deeply supercooled temperatures at ambient pressure. The isothermal compressibility and isobaric heat capacity show maxima near 223 K, in excellent agreement with recent experiments, and the liquid density exhibits a minimum at ∼208 K. A local tetrahedral arrangement, where each water molecule accepts and donates two hydrogen bonds, is found to be the most probable hydrogen-bonding topology at all temperatures. This work suggests that MB-pol may provide predictive capability for studies of liquid water's physical properties across broad ranges of thermodynamic states, including the so-called water's "no man's land" which is difficult to probe experimentally.

Dynamics of electrified jets in electrohydrodynamic atomization

An electrified jet ejected from a meniscus (or Taylor cone) can further disintegrate into fine drops with different modes in electrohydrodynamic atomization (EHDA). This process has been applied into many fields because of controllable production of highly charged and monodispersed drops. However, both stable and unstable electrified jets are encountered in EHDA, usually depending on liquid physical properties and operating parameters. A series of electrified jets are visualized and the transient breakup dynamics are analyzed within an electric field. According to the geometry forms of drops or/and jets emitted from the end of a needle, periodic dripping, pulsating-jet, stable-jet, and unstable jet are clearly classified. The operating parameters versus spraying modes are also discussed, especially for propylene glycol and n-octanol. The initial velocity from the Taylor cone, jet breakup length, jet position, and the size separation effect are deeply studied. The jet velocity is significantly accelerated by electric stresses and good agreement with predicted value. The jet breakup length increases sharply as liquid flow rate increasing and slowly increases as electric potential increasing, except for small liquid flow rate where bullet cone occurs. The jet ejection point varies and gradually deflects off needle axis with an increase in electric potential. The ‘size separation effect’ can help improve the quality of printing by removed highly charged satellite drops.

Study on spilled liquid from a continuous leakage in sloped tunnels

The study focuses on the behaviors of spilled liquid from a continuously leaked tank in sloped tunnels. Spillage width and area, which impact the potential heat release rates in case of fire, are investigated under different tunnel slopes and leakage flow rates by numerical simulations using interFoam based on the VOF method in the OpenFOAM toolbox following the validation. The simulation results show that the spillage width initially decreases rapidly and then slowly as the tunnel slope increases. Other parameters, including road surface roughness, physical properties of liquid and leakage source height, are also considered. Empirical models for predicting the spillage width and area are established considering both tunnel slope and leakage flow rate. The results may provide guidance for tunnel safety design and drainage system design affiliated with a tank leakage inside a tunnel.

Medium-range atomic correlation in simple liquids. I. Distinction from short-range order.

Physical properties of liquids and glasses are controlled not only by the short-range order (SRO) in the nearest-neighbor atoms but also by the medium-range order (MRO) observed for atoms beyond the nearest neighbors. In this article the nature of the MRO as the descriptor of point-to-set atomic correlation is discussed focusing on simple liquids, such as metallic liquids. Through the results of x-ray diffraction and simulation with classical potentials we show that the third peak of the pair-distribution function, which describes the MRO, shows a distinct change in temperature dependence at the glass transition, whereas the first peak, which represents the SRO, changes smoothly through the glass transition. The result suggests that the glass transition is induced by the freezing of the MRO rather than that of the SRO, implying a major role of the MRO on the viscosity of supercooled liquid.

A modeling study of different kinds of sessile droplets on the horizontal surface with surface wettability and gravity effects considered

Droplet phase change is important for energy storage and saving technology. The initial profile of the droplet is extremely important for its vaporization or solidification on a horizontal surface. To understand the effect of liquid physical properties on droplet profile, a theoretical model was developed in this study, based on the Young-Laplace equation with gravity effect specially considered. After the model was experimentally validated by comparing the geometric shape of water droplets, it was further used for predicting droplet shapes of other materials, and thus analyzing the influence of different physical properties, such as temperature, pressure, surface wettability, etc. Results show that the results of this model agree well with the experimental data. The maximum and average deviations are less than 4.5% and 1.5%, respectively. For all kinds of droplets on the fixed surfaces, when the temperature increases, the droplet contact radius increases and height decreases. The droplets of nitrogen and carbon dioxide are more sensitive to temperature than ethanol and ethylene glycol droplets. For 20 μL droplets on the surface of contact angle 150°, when the temperature changes from 273.15 K to 293.15 K, the droplet contact radiuses increase by 30.6% for carbon dioxide, 1.2% for ethanol and 0.67% for ethylene glycol, and the droplet heights decrease by 42.9%, 2.5%, 1.1%, respectively. Results of this study are meaningful for predicting the phase change process of droplets on the horizontal surface by controlling their initial profiles.

Effect of Fluid Properties on Contact Angles in the Eagle Ford Shale Measured with Spontaneous Imbibition.

Models of fluid flow are used to improve the efficiency of oil and gas extraction and to estimate the storage and leakage of carbon dioxide in geologic reservoirs. Therefore, a quantitative understanding of key parameters of rock–fluid interactions, such as contact angles, wetting, and the rate of spontaneous imbibition, is necessary if these models are to predict reservoir behavior accurately. In this study, aqueous fluid imbibition rates were measured in fractures in samples of the Eagle Ford Shale using neutron imaging. Several liquids, including pure water and aqueous solutions containing sodium bicarbonate and sodium chloride, were used to determine the impact of solution chemistry on uptake rates. Uptake rate analysis provided dynamic contact angles for the Eagle Ford Shale that ranged from 51 to 90° using the Schwiebert–Leong equation, suggesting moderately hydrophilic mineralogy. When corrected for hydrostatic pressure, the average contact angle was calculated as 76 ± 7°, with higher values at the fracture inlet. Differences in imbibition arising from differing fracture widths, physical liquid properties, and wetting front height were investigated. For example, bicarbonate-contacted samples had average contact angles that varied between 62 ± 10° and ∼84 ± 6° as the fluid rose in the column, likely reflecting a convergence–divergence structure within the fracture. Secondary imbibitions into the same samples showed a much more rapid uptake for water and sodium chloride solutions that suggested alteration of the clay in contact with the solution producing a water-wet environment. The same effect was not observed for sodium bicarbonate, which suggested that the bicarbonate ion prevented shale hydration. This study demonstrates how the imbibition rate measured by neutron imaging can be used to determine contact angles for solutions in contact with shale or other materials and that wetting properties can vary on a relatively fine scale during imbibition, requiring detailed descriptions of wetting for accurate reservoir modeling.

Slow Pyrolysis of Flax Production Waste

The slow pyrolysis of flax shive and the cellulose residue of flax shive obtained by ethanolysis was studied in this work. Investigation of temperature effect on physical properties of pyrolysis products in the range of 500-750 o? on a laboratory slow pyrolysis unit was presented in this manuscript. The experimental obtained data of initial properties of investigation samples, thermal stability of samples, heat effects of pyrolysis process, chemical composition and physical properties of liquid and gaseous pyrolysis products are presented.

A Power Sequence Interaction Function for Liquid Phase Particles

In this manuscript, a function is derived that allows the interactions between the atoms/molecules in nanoparticles, nanodrops, and macroscopic liquid phases to be modeled. One goal of molecular theories is the development of expressions to predict specific physical properties of liquids for which no experimental data are available. A big limitation of reliable applications of known expressions is that they are based on the interactions between pairs of molecules. There is no reason to suppose that the energy of interaction of three or more molecules is the sum of the pairwise interaction energies alone. Here, an interaction function with the limit value w = e2π/e is presented, which allows for the derivation of the atomic mass unit and acts as a bridge between properties of elementary particles and emergent properties of macroscopic systems. The following properties of liquids are presented using the introduced interaction function: melting temperatures of n-alkanes, nanocrystals of polyethylene, melting temperatures of metal nanoparticles, solid–liquid phase transition temperatures for water in nanopores, critical temperatures and critical pressures of n-alkanes, vapor pressures in liquids and liquid droplets, self-diffusion coefficients of compounds in liquids, binary liquid diffusion coefficients, diffusion coefficients in liquids at infinite dilution, diffusion in polymers, and viscosities in liquids.

Preparation of microbubbles with the generation of Dean vortices in a porous membrane

A platform based on gas–liquid membrane dispersion with helical internals inserted is developed for microbubble generation. The effects of internals on microbubble size are investigated, including circular, helical, twisted, and polygonal geometries. Parametric studies are conducted by varying the liquid flow velocity, liquid physical properties, geometric shape, helical pitch and thickness. Compared with membranes developed with other internals inserted, the membrane with helical internals has the highest performance for microbubble generation. The size of microbubbles decreases with increasing helical pitch and decreasing helical thickness in different liquid phases. CFD simulation is used to reveal the flow field with internals inserted into the membrane, which indicates that Dean vortices are effectively generated by inserting helical internals. An empirical correlation describing the microbubble size in the metallic membrane is developed considering the contribution of the gas–liquid ratio, capillary force and Dean vortices, showing good agreement with experimental data.

Electrical and acoustic investigation of partial discharges in two types of nanofluids

Measurements of partial discharges in liquid dielectrics are important for prediction of a serious failure of electrical equipment. Recent research findings show that application of nanoparticles in dielectric liquids may increase their resistance to partial discharges. However, physical properties of a host liquid are expected to play a decisive role in the effective suppression of partial discharges by nanoparticles. In this paper, a transformer oil prepared by a gas-to-liquid technology and a standard naphthenic transformer oil are doped with an equal amount of iron oxide nanoparticles. Determination of basic physical properties of the oils and the nanofluids is followed by an experimental investigation of partial discharges under various alternating voltage levels. The detection of partial discharges is approached by two independent methods, electrically and acoustically. Both methods revealed occurrence of partial discharges in the gas-to-liquid oil at higher voltages, as compared with the naphthenic oil. Acoustic emission energy is found one order of magnitude greater in the gas-to-liquid oil than in the naphthenic oil. The acoustic wave propagation dependence on the physical properties of the liquid is considered in the qualitative explanation of the observed phenomenon. The presence of nanoparticles can suppress partial discharges in the naphthenic oil, but not in the gas-to-liquid oil.

Physical properties of (Mn1−xCox)Si at x≃0.060–0.100 : Quantum criticality

We have grown and characterized three samples of Co doped MnSi and studied their physical properties (magnetization and magnetic susceptibility, heat capacity and electrical resistance). All three samples show non-Fermi liquid physical properties. From literature data and current results follow that impurities (Co and Fe) eliminate the first order phase transition peaks and spread the fluctuation maxima in such a way that its low temperature part effectively reaches the zero temperature, where the fluctuations inevitably become quantum. The behavior of low temperature branches of the heat capacity of the samples suggests that a gradual transition from classical to quantum fluctuations can be described by a simple power function of temperature with the exponent less than one. The $d\rho/dT$ data generally support this suggestion. The values of the heat capacity exponents immediately lead to the diverging ratio $C_p/T$ and hence to the diverging effective electron mass. We found out that at large concentration of the dopant there are no distinct phase transition points. What we observe is a cloud of the helical fluctuations spreading over a significant range of concentrations and temperatures, which become quantum close to 0~K.

Investigating the effect of nonionic surfactant on the silica nanoparticles formation and morphology in a microfluidic reactor

The conventional sol-gel method used to synthesize monodispersed spherical silica nanoparticles produces particles with irregular shapes and low monodispersity. Microreactors show a promising new platform to synthesize nanomaterials due to their unique flow and mixing characteristics. In most known shear-based droplet generation microreactors, the effect of the flowing liquid’s physical properties on the reactor performance and product characteristics are not well investigated. Scaling-down the flow system was proven to change the flow behavior which will be dominated by the liquid apparent physical properties that are highly controllable. A new method to synthesize silica nanoparticles adapting the sol-gel approach in a microfluidic chip is proposed and experimentally tested in the present work. This work also analyzes changing the flowing reactants’ physical properties using nonionic surfactants with different concentrations on the reaction performance and nanoparticle size and properties. A custom-made microreactor, made from polydimethylsiloxane, was designed and then fabricated using a direct writing technique. The investigated surfactant concentration was within the range of 1 to 5 vol/vol%, respective to tetraethyl orthosilicate. A traditional bench-scale sole-gel method was also performed with the same reaction properties for comparison purposes. The obtained nanoparticles were characterized using transmission electron microscopy and EDX. The silica nanoparticles synthesized from a bench-scale system showed poor monodispersity and an irregular shape compared to the perfect spherical particles produced from the microflow system. The addition of surfactant reduced the coalescence of the droplet besides reducing the size of the droplets. Increasing the surfactant concentration reduces the silica nanoparticle size. The results showed that highly monodispersed silica nanoparticles with an average size of 5.76 ± 1.27 nm were synthesized using the microflow system comparing to silica nanoparticles with a mean size of 95 ± 4 nm produced from the bench-scale.

НЕКОТОРЫЕ ОСОБЕННОСТИ ИЗЛОЖЕНИЯ ВОПРОСА О СЖИМАЕМОСТИ ЖИДКОСТИ В КУРСАХ ГИДРАВЛИКИ ДЛЯ СТРОИТЕЛЬНЫХ И ПРИРОДООХРАННЫХ СПЕЦИАЛЬНОСТЕЙ

The article analyzes the features of taking into account the compressibility of a liquid in solving problems of hydraulics and the operation of hydraulic systems. Particular attention is paid to the completeness of the consideration of the physical properties of liquids in the study of the discipline "Hydraulics" in accordance with the formation of research competencies and the direction of professional training of bachelors.

Parametric study on stability and morphology of liquid cone in flow focusing

A parametric study on the stability and morphology of the liquid cone in a flow focusing process is carried out through experimental and numerical methods. For the numerical simulations, we solve the Navier-Stokes equations coupled with a diffuse interface method. A scaling analysis which considers the competition between the viscous shear stress and the interfacial tension force is proposed, showing the effect of flow rates, geometrical parameters and liquid physical properties on the cone instability. The experimental and numerical results validate the scaling law and further show the effects of parameters on the cone morphology. We study the flow fields inside the liquid cone, with emphatic focus on the recirculation flow pattern which occurs at relatively high viscosity ratio between the focusing and the focused liquids. The occurrence of recirculation flow is close related to the tangential velocity distribution at both sides of the cone interface, and the change of flow rates and geometrical parameters is found to significantly affect the size of the recirculation flow. This study is expected to give a guidance to the optimization of process parameters in flow focusing system, which would contribute to the formation of a stable cone-jet structure and the production of microdroplets with high throughput.

Digitonin concentration is determinant for mitochondrial supercomplexes analysis by BlueNative page

The BlueNative page (BNGE) gel has been the reference technique for studying the electron transport chain organization since it was established 20 years ago. Although the migration of supercomplexes has been demonstrated being real, there are still several concerns about its ability to reveal genuine interactions between respiratory complexes. Moreover, the use of different solubilization conditions generates conflicting interpretations. Here, we thoroughly compare the impact of different digitonin concentrations on the liquid dispersions' physical properties and correlate with the respiratory complexes' migration pattern and supercomplexes. Our results demonstrate that digitonin concentration generates liquid dispersions with specific size and variability critical to distinguish between a real association of complexes from being trapped in the same micelle.

Instability and interface coupling of coaxial liquid jets in a driving stream

The behavior of jet breakup and interface coupling in a co-flow focusing (CFF) process is studied theoretically. A physical model of coaxial liquid jets moving in an infinite annular driving stream is established, and the dimensionless dispersion relation for temporally axisymmetric perturbations is solved numerically. The effects of process parameters such as flow velocities, liquid physical properties, and radius ratio between the inner and outer jets on the jet instability are analyzed. The evolutions of interface perturbations are observed in CFF experiments, and the perturbation wavelengths under different liquid flow rates are measured in comparison with theoretical predictions. Moreover, the coupling of interface instabilities in CFF is studied through changing the radius ratio between the inner and outer liquid jets. In particular, two simplified single jet models under the assumption of minimum inner and outer liquid flow rates are proposed to reveal the transition from weak coupling to strong coupling of jet interfaces. This work provides great insight into the physical mechanism of interface instability in CFF advantageous for producing monodisperse microdroplets with fine robustness and high throughput.

Variation of gas phase combustion properties of complex fuels during vaporization: Comparison for distillation and droplet scenarios

Surrogate mixtures for modeling real fuels are formulated based on gaseous combustion property targets and liquid physical properties. A batch distillation model was developed to evaluate the vaporization characteristics of some existing surrogates for Jet-A. Chinese aviation fuel RP-3 was then used as a target to experimentally obtain distillation curves and variation of chemical functional groups. A 24-component surrogate was formulated mainly to capture the distillation behavior of RP-3. This surrogate was then used in two droplet vaporization models (Finite Thermal Conductivity/Finite Diffusivity (FTC/FD), Infinite Thermal Conductivity/Infinite Diffusivity (ITC/ID)) to investigate the effects of preferential vaporization on gaseous combustion properties of a complex real fuel. The results obtained from FTC/FD and ITC/ID provide regional bounds for droplets in a vaporizing spray. Four combustion property targets (Molecular Weight (MW), Hydrogen to Carbon ratio (H/C), Derived Cetane Number (DCN) and Threshold Sooting Index (TSI)) were employed as indicators of gas combustion properties. It was found that due to a wide distribution of compounds’ volatility, gaseous combustion properties vary significantly during droplet vaporization. The results suggest development of vaporization models that well capture preferential vaporization of a target real fuel for further spray modeling.

Properties of Thin Lithium Metal Electrodes in Carbonate Electrolytes with Realistic Parameters.

To understand the baseline performance of lithium (Li) anode in liquid electrolytes, the electrochemical and physical properties of the Li anode are studied with realistic parameters, including thin thickness (50 μm), practical areal capacity (1-4 mA h cm-2), practical areal current (0.5-2 mA cm-2), and low electrolyte/capacity ratio. Two different Li salts, lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI), are used to probe the effects of the electrolyte chemistry and concentration. The cycling of Li/Li symmetric cells, combined with the scanning electron microscopic investigation, demonstrates that the soft-short of Li/Li cells is induced by the continuous volume expansion of Li electrodes during cycling instead of dendrites. The volume change of a Li electrode is dictated by the depth of deposition and stripping (i.e., areal capacity) and the electrolyte/capacity ratio, with no strong correlation with the type of Li salt and concentration. On the other hand, the average Coulombic efficiency (CE) measurement demonstrates inherent correlation with the type of Li salt and its concentration in the electrolyte. Li electrode surface chemical analysis indicates that the fluoride-rich surface layer formed in the LiPF6 electrolyte can be detrimental to both CE and Li deposition-stripping overpotential.

Air entrainment and granular bubbles generated by a jet of grains entering water

HypothesisA water jet penetrating into a water pool produces air entrainment and bubbles that rise to the surface and disintegrate. A similar scenario can be expected when a granular jet enters into water. This phenomenon is common in natural and industrial processes but remains so far unexplored. ExperimentsA collimated jet of monodisperse silica beads was poured into water and the process was filmed with a high-speed camera. The grain size, jet impact velocity, and the liquid physical properties were systematically varied. FindingsFor grains of ~50–300μm in diameter, the granular jet deforms the air-water interface, penetrates the pool and produces air entrainment. Most of the entrained air is contained in the interstitial space of the jet, and its volume is linearly proportional to the volume of grains. The bubbles formed in this process are covered by a layer of grains attached to the bubble air-water interface due to capillary-induced cohesion. These “granular bubbles” are stable over time because the granular shell prevents coalescence and keeps the air encapsulated, either if the bubbles rise to the surface or sink to the bottom of the pool, which is determined by the competition of the buoyancy and the weight of the assembly.

ВТОРИЧНЫЕ КАРБОНАТЫ ЮРСКИХ ПЕСЧАНЫХ ОТЛОЖЕНИЙ КАК ПОКАЗАТЕЛИ ПРОДУКТИВНОСТИ ПАЛЕОЗОЯ

Работа основана на концепции глубинного генезиса флюидов с последующей субвертикальной миграцией (снизу вверх) по проницаемым зонам и разгрузкой в вышележащих коллекторах. Причем в зонах разгрузки и на путях миграции флюидов происходят геохимические преобразования аллотигенных минералов. Интенсивности процессов вторичного, наложено-эпигенетического образования минералов зависят от физико-химических свойств жидкости и скорости её течения. Целью статьи является иллюстрация связи интенсивности процессов вторичной карбонатизации юрских песчаных отложений с характером насыщения палеозойских пород. Методы. Интенсивность вторичной карбонатизации определялась по инновационной технологии статистической интерпретации материалов геофизических исследований скважин. Проводились сопоставления полученных статистических интенсивностей с результатами литолого-петрографических, минералогических исследований керна на предмет содержания карбонатов и с результатами испытаний палеозойских коллекторов. Актуальность работы обусловлена появившейся возможностью с высокой вероятностью выявлять зоны расположения нефтегазовых залежей в фундаменте по результатам статистической интерпретации данных геофизических исследований скважин юрских отложений, используя материалы старого фонда. Объектом исследования явились песчаные пласты юрского возраста Герасимовского месторождения (Томская область), а также карбонатные минералы, расположенные в песчаной породе. Выводы. Усреднённая интенсивность процесса вторичной карбонатизации в юрских песчаных отложениях является индикатором характера насыщения палеозойских пластов. С ростом интенсивности карбонатизации юрских пластов увеличивается вероятность обнаружения нефтенасыщенных залежей в фундаменте. С точки зрения выявления продуктивных залежей палеозоя наиболее информативным карбонатным минералом в юрских пластах является аутигенный сидерит.