Low Liquid Research Articles

Exploring the Thermal Potential of Shape Stabilized Graphene Nano Platelets Enhanced Phase Change Material for Thermal Energy Storage

Low thermal conductivity and liquid phase leakage impede the widespread adoption of phase change materials (PCMs). To enhance PCM performance and practical viability, addressing these limitations is crucial. Current study addresses low thermal conductivity and leakage issues. Enhanced thermal conductivity in PCMs is achieved by adding graphene nanoplatelets (GnPs), while expanded graphite (EG) acts as a leak‐proof barrier. The composite PCM (ss‐NePCM) composite is developed by ultra‐sonication followed by vacuum impregnation process. The samples underwent comprehensive analysis: thermal conductivity (TEMPOs), chemical composition (FTIR), photo‐transmittance (UV–Vis), and thermal stability (TGA). The results show that the composite with 0.6 wt% GnP (NePCM3) has the highest thermal conductivity enhancement of ≈112% while adding 15 wt% EG (ss‐NePCM3) diminishes leakage problem. According to the optical performance assessment, the composite exhibits a notable increase in absorbance of 116% higher than that of the base PCM. However, due to the introduction of additives, the differential scanning calorimeter (DSC) detected a minor variation from 154 to 144.76 J g−1 in the latent heat. Furthermore, the composite demonstrates chemical stability and thermal reliability following 250 heating and cooling cycles. The ss‐NePCM holds promise for thermal systems, where leakage could jeopardize system integrity.

Gamma positioning and market quality

In this paper, we study the effect of the gamma positioning of dynamic hedgers on market quality through simulations. In our zero-intelligence model, the presence of dynamic hedgers enhances market liquidity under normal conditions. However, positive gamma helps sustain liquidity in stressed scenarios, while negative gamma depletes it. We find that an increase in the net gamma positioning of dynamic hedgers reduces volatility and increases market stability, whereas a negative gamma positioning increases volatility and makes the market more prone to failure. Price discovery typically worsens when dynamic hedgers become more prevalent, regardless of the sign of their positioning. Our findings imply that steering the net gamma position of dynamic hedgers can be considered a policy instrument to improve market quality, especially for instruments with low liquidity or low traded volume.

Ammonia – an assessment of potential environmental impacts including prevention and mitigation measures

Ammonia (chemical formula NH3) is one of the most widely produced chemicals for industrial and agricultural uses. Ammonia has gained attention as a potential hydrogen and energy carrier, and low carbon substitute fuel for rail and maritime transport. The potential of ammonia for new use cases may lead to an increased footprint of potential environmental impacts. The physical and chemical properties of ammonia offer significant benefits for transportation and storage, but challenges remain due to its highly toxic nature and uses outside of dedicated industrial precincts. Ammonia is typically liquefied to increase density for ready storage and transportation. Unplanned releases of liquid ammonia will result in immediate environmental impacts. Unplanned releases may adversely affect receptor species in aquatic and terrestrial environments, human health, as well as the reputation of the responsible organisation. Dispersion of ammonia into the environment depends on factors that include mixture density, temperature, humidity, wind and wave action, and release mode and direction. Understanding the fate of ammonia is fundamental to adoption of effective mitigation measures. Consequently, it is necessary to understand the behaviour of ammonia in the environment, how unplanned releases can be minimised, and how they can be combatted, in order to appraise its suitability as a low carbon liquid transport fuel. This paper assesses the risks posed by ammonia spills, its fate in aquatic environments, and the applicability of available spill models. It also addresses management measures for the prevention and mitigation of spills noting the highly soluble and toxic nature of the chemical.

Absorption characteristics and molecular mechanism of a low viscosity iron-based ionic liquid for removing H2S

Aiming at the problem of by-product salt and volatile solvent component in industrial liquid redox process of H2S removal. A new absorbent, a 1-butyl-3-methylpyridine iron-based ionic liquid (rFeCl3/[BMP]Cl) with three iron-pyridine ratios (r=0.6, 0.8, and 1.0), was synthesized. The physicochemical properties and H2S solubility of rFeCl3/[BMP]Cl were measured and modeled. The molecular mechanism of chemical absorption of H2S by iron-based ionic liquids was explained from the interaction energy, reduced density gradient (RDG) and atoms in molecules (AIM) topology analysis, and standard reaction equilibrium constant by quantum chemical calculation. It was found that rFeCl3/[BMP]Cl have low viscosity, high solubility, and good thermal stability. Its Bronsted acidity avoids by-product salts produced in the absorption of H2S. The hydrophobicity makes the ionic liquid not diluted by the generated water during the absorption. The results of quantum chemical calculations show that rFeCl3/[BMP]Cl-H2S has moderate intermolecular interaction and large reactivity, which is consistent with the experimental results of the Henry's coefficient and reaction equilibrium constant.

Low Temperature Dynamic Polaron Liquid in a Manganite Exhibiting Colossal Magnetoresistance.

Polarons-fermionic charge carriers bearing a strong companion lattice deformation-exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in insulators, how they evolve in transitions to metallic and superconducting states in quantum materials remains an open question. Here, we use resonant inelastic x-ray scattering to track the electron-lattice coupling in the colossal magneto-resistive bi-layer manganite La_{1.2}Sr_{1.8}Mn_{2}O_{7} across its metal-to-insulator transition. The response in the insulating high-temperature state features harmonic emissions of a dispersionless oxygen phonon at small energy transfer. Upon cooling into the metallic state, we observe a drastic redistribution of spectral weight from the region of these harmonic emissions to a broad high energy continuum. In concert with theoretical calculations, we show that this evolution implies a shift in electron-lattice coupling from static to dynamic lattice distortions that leads to a distinct polaronic ground state in the low temperature metallic phase-a dynamic polaron liquid.

Effect of fracture distribution on extraction efficiency in low-permeability NAPL-contaminated formations

Hydraulic fracturing offers an effective solution to the challenge of remediating low-permeability contaminated formations by improving substance transport rates. In this study, COMSOL Multiphysics, a large-scale multi-physics coupled simulation software, was employed to simulate enhanced extraction and remediation of low permeability non-aqueous phase liquid (NAPL)-contaminated formations using hydraulic fractures. The results obtained indicate that fracturing and enhanced extraction can effectively improve the NAPL removal rate. The NAPL removal rate increased with increasing depth of the extraction well screens, fracture length, and fracture spacing. Through a coupling analysis of multiple factors and working conditions, the extraction well screens are suggested to be buried within the lower one-third of the low-permeability contaminated formation, and the length of a single fracture should be within 50%–80% of the extraction radius. When the distance between the two fractures was greater than 1.75 m, the enhancement effect of the fracture length was further promoted. Consequently, a reasonable configuration of fracture length, quantity, and spacing can effectively broaden the influence radius of extraction wells.

Water adsorption on microporous chabazites as thermal energy storage materials

Thermochemical energy storage can reduce fossil fuel consumption, which is still dominant in heating of buildings. The efficiency of the sorption technology is determined by the performance of the adsorbent, which should have a high water adsorption capacity and, consequently, a high energy storage density, stability under humid conditions, and fast kinetics of adsorption and desorption. In this study we investigated the effect of different elemental compositions of the commercial and laboratory prepared microporous aluminophosphates, natural and synthetic zeolites with chabazite structure and their modifications in powder and granular form on water adsorption capacity. The highest water uptake among the aluminophosphates was found for APO-34-IL, which was prepared by green synthesis with the low cost ionic liquid, while the highest water uptake of all the samples analysed was found for the composites of the natural zeolite with CaCl2.

Rotating heat pipe model based on lumped parameter method

On the basis of many theoretical studies about rotating heat pipes, a simplified mathematical model is established based on the lumped parameter method, ignoring the temperature difference inside each section of the heat pipe is ignored, and comparing the calculated results with the experimental data. It is identified that this model has a good applicability at high speeds and low liquid filling rates, and effectively reduces the amount of calculation, which is of practical significance to the engineering application of rotating heat pipes.

Novel approach: Simultaneous application of ionic liquid doped polymer electrolyte in supercapacitor and dye-sensitized solar cells

The present study reports the synthesis, characterization, and application as energy devices of an ionic liquid blended polymer electrolyte film in which the host polymer polyvinyl alcohol (PVA) is mixed with low viscosity ionic liquid (IL) 1-ethyl-3-methylimidazolium thiocyanate. Various characterization tools have been used further to elaborate electrical, structural, and photoelectrochemical properties. X-ray diffraction (XRD) and polarized optical microscope (POM) affirm the reduction of crystallinity of polymer, while Fourier transform infrared spectroscopy (FTIR) shows complexation and composite nature. Electrochemical impedance spectroscopy shows an enhancement in ionic conductivity by IL doping, where the highest conductivity is achieved at 60 wt% of IL concentration with a conductivity value of 6.21 × 10⁻⁴ S/cm. The ionic transference number (tion) and electrochemical stability measurement show the film's predominantly ionic nature and a reasonable stability window. Using maximum conducting film sandwiched between electrodes, we have successfully fabricated two devices, i.e., an electrical double-layer capacitor (EDLC) and a dye-sensitized solar cell (DSSC). The fabricated EDLC capacitor shows a specific capacitance of 125 F/g, while DSSC shows an efficiency of 1.1 % at one sun condition.

DEVELOPMENT OF DOWNHOLE PUMP VALVE ASSEMBLY

The purpose of the work is modernization of the valve, in order to increase reliability, wear resistance, increase the pump flow and reduce the load on the rod string, as well as improve durability. The sucker rod pump is one of the most popular and extensively utilized artificial lift systems. It is a frequently chosen option for lifting oil because of its fundamental simplicity, low operating costs, and adaptability in power supply. In the long run of oil production history, sucker-rod pumping was the first option—and frequently the only option—when artificial lift was required. For this reason, the oldest and most popular method of producing oil wells worldwide is sucker-rod pumping. Since the steel used to make rods has limited strength, sucker-rod pumping is typically thought of as a way to raise moderate to low liquid production rates from shallow to medium well depths due to depth restrictions. Since the correct working of the standing and traveling valves is largely responsible for an efficient pumping operation, valves are regarded as the heart of the sucker-rod pump. The extremely high differential pressures across the valve during pumping necessitate a highly dependable sealing action between the ball and the seat. Small initial flaws in the sealing surfaces or subsequent corrosion- or abrasion-related problems result in greater liquid slipping and a quick decline in valve function because of fluid cutting. Subsurface pumps using traditional ball-and-seat valves suffer a number of basic operational issues: • Because of the greatly high number of pumping cycles per day, the sealing surfaces may sustain significant damage from the frequent collision of the two parts against one another. • In deviated wells, valve wear is uneven and can cause premature failure. • Typical cage constructions, meant to limit impact damage, typically restrict the flow area available through the valve and can be the source of pumping inefficiencies due to low fillage of the pump barrel. Keywords: sucker rod pumps, downhole pump, traveling valve, standing valve, valve assembly.

Palladium-catalyzed synthesis of low viscosity hyperbranched liquid polyethylene and its polar copolymers

In this investigation, we designed and synthesized a range of pyridine-imine Pd(II) complexes featuring 2-aryl and 6-diphenylmethyl substituents. These catalysts were specifically tailored for the preparation of hyperbranched polyethylene oils (HBPEOs) and polar-functionalized hyperbranched polyethylene oils (PFHBPEOs). The catalysts exhibited high activity in the synthesis of HBPEO, achieving rates as high as 2.97–17.67 × 104 g mol−1 h−1. The resulting products were characterized by low molecular weights ranging from 307 to 500 g/mol, high branching densities of 113–138/1000C, and correspondingly low viscosities. While demonstrating moderate activity in the range of 0.7–6.2 × 103 g mol−1 h−1 for the synthesis of PFHBPEO, the polar-functionalized hyperbranched polymers retained similar characteristics of low molecular weight (325–436 g/mol), high branching density (112–141/1000C), and low viscosity. Notably, the PFHBPEOs obtained through this process exhibited an exceptionally high insertion ratio (7.4–16.0 mol%) of MA, with the ester group positioned terminally on the long chain branching. NMR analysis further confirmed the presence of a diverse range of branching structures, with a significant proportion of hyperbranched motifs, in both HBPEO and PFHBPEO. Importantly, variations in the catalyst structure and polymerization conditions were found to significantly influence the activity, structural features, and properties of the resulting HBPEO and PFHBPEO.

Peptidoglycan modulation by Francisella tularensis

HAYDEN HESS, STUART CANTLAY, JOSEPH HORZEMPA, Department of Biomedical Sciences, West Liberty University, West Liberty, WV 26074 and MELANIE SAL, Department of Biology, West Virginia Wesleyan College, Buckhannon, WV 26201. Peptidoglycan modulation by Francisella tularensis. Peptidoglycan, a crucial component of bacterial cell walls, plays a fundamental role in maintaining cell shape, integrity, and resistance to osmotic pressure. Mycoplasmas are the only bacteria that do not produce peptidoglycan cell walls. Other peptidoglycan-producing bacteria are capable of transiently existing without a peptidoglycan as an “L-form”, but only on solid media. Preliminary observations made by our laboratory suggested that Francisella tularensis bacteria do not produce detectible levels of peptidoglycan while growing in liquid media. However, increasing salt concentration induces the production of peptidoglycan in all bacteria. In this study we confirmed and extended these observations by incubating bacteria with fluorescent D-alanine (which integrates into the peptidoglycan during synthesis). Fluorescence microscopy revealed that very few F. tularensis bacteria produce detectable peptidoglycan in low salt media, while seemingly all individual bacteria produce this layer in high salt media. Interestingly, the genome of F. tularensis encodes two distinct beta-lactamases. Here we show that both the wild-type F. tularensis LVS and beta-lactamase null mutant were both resistant to high levels of beta-lactam antibiotics in low salt liquid media. However, only the wild type and complemented mutant strains were resistant to beta-lactam antibiotics in high salt media while the beta lactamase null mutant was susceptible. These data further support the conclusion that F. tularensis does not produce, nor need, peptidoglycan in low salt liquid media. Future studies will investigate whether peptidoglycan modulation is required to avoid detection by the innate immune system.

Crack generation and propagation mechanism of Mo[sbnd]14Re alloy laser welding

This paper investigates the mechanism of crack generation and propagation in laser-welded joints of Mo14Re alloy plates. The study utilized optical microscopy (OM) and scanning electron microscopy (SEM) to examine the microstructure and morphology of the crack area in the Mo14Re laser-welded joint. Additionally, energy dispersive spectroscopy (EDS) was employed to characterize the elements at the crack defect, while electron backscatter diffraction (EBSD) was utilized to analyze the grain boundary and crystal orientation at the crack defect.The analysis of crack formation and propagation considered various factors, including grain boundary segregation, characteristics of grain boundaries and crystal orientation, and the Schmidt factor. The findings revealed that cracks formed in the weld area exhibited distinct characteristics of brittle fracture along the grain. Notably, these cracks displayed evident carbon and oxygen segregation attributed to the presence of a low melting point eutectic liquid film. The segregation, along with high-temperature compounds on the fracture surface, emerged as the primary factors contributing to crack formation.In the proximity of the crack, there exists a concentration of strain, inducing plastic deformation and thereby facilitating crack initiation. Cracks exhibit a tendency to originate along large-angle grain boundaries and deflect along these boundaries. Owing to the difference in atomic slip characteristics on both sides of the crack, the direction of crack propagation is more inclined to deflect towards grains with a smaller Schmidt factor.

Моделирование движения обвальной массы горной породы с использованием двухжидкостной математической модели

Introduction. Rock falls are considered to be very dangerous slope processes that can lead to serious consequences. In addition to real observations, numerical (mathematical) or experimental (physical) modeling methods are used to study slope processes. Mathematical modeling is used in the cases where experimental data is insufficient. There are quite a lot of models to describe slope processes. The choice of model to describe a particular slope process lies in the approach on which the model is based. In this work, the debris flow taking into account the fluidization of the collapse mass during its movement along the hillside was described. We used a two-fluid model based on the continuum approach and the kinetic theory of granular gas. The model takes into account the fluidization of the collapse mass, and its implementation does not require the use of powerful computing resources. Purpose of the study. Investigation of the collapse mass motion along a hillside using a two-fluid model based on continuum approach and kinetic theory of granular gas. Estimation of the maximum height of the collapse mass flow layer and the average flow velocity. Materials and methods. The two-fluid model based on the continuum approach and the kinetic theory of granular gas was used for theoretical study of the collapse mass flow. The motion of the collapse mass flow consisting of rock granules (average diameter 7.5 cm) along the hillside (slope angle of 30 degrees) was considered. The 3D simulation results obtained using the two-fluid model were compared with experimental data and calculated data obtained using the discrete element method. The results and discussion. Three-dimensional modeling was applied to study the motion of the collapse mass flow along the hillside using the two-fluid model. The obtained calculations of the maximum height of the flow layer and the average flow velocity are compared with experimental data and calculated data using the discrete element method. The comparison showed that the averaged value (obtained as the arithmetic mean) of the experimental data of the average flow velocity coincides with the result of calculations using the two-fluid model. And the average value of the calculated data using the discrete element method differs slightly from the calculated value using the two-fluid model. The paper proposes a method for calculating the maximum height of the flow layer using graphs of the distribution of the particles volume fraction along the normal to the inclined surface. Using this technique, the maximum value of the layer height was obtained. This value coincides with the maximum value obtained using the discrete element method and differs only slightly from the maximum value obtained in the experiments. Using the two-fluid model, additional calculations were carried out at different values of the slope angle in the range from 20 to 60 degrees. The calculation results of the maximum height of the flow layer and average flow velocity were compared with the calculated data obtained using a model based on the discrete element method. It was found that the calculation results obtained using two different models agree better with each other when the dependence of the average flow velocity on the slope angle is studied. Conclusion. In general, it can be concluded that the results of calculations of the maximum layer height and average flow velocity obtained using the two-fluid model are in fairly good agreement with experimental data and calculated data obtained using the discrete element method. It can also be concluded that the two-fluid model can be used to describe the motion of the flows of the collapse mass with a relatively low liquid content (up to 18 %) and fine inclusions (up to 27 %). Resume. The research results can be useful in estimating the maximum height of the flow layer of the collapse mass and the average flow velocity. The direction of future research is to improve the two-fluid model based on the continuum approach and the kinetic theory of granular gas for describing of real slope processes.

Effect of viscosity on bubble spreading on flat solid surfaces

The behavior and dynamics of bubble spreading has a great impact on interfacial contact area and time, which is significant for the heat/mass transfer or separation efficiency. In this work, the dynamical behavior of bubble spreading especially the three-phase contact line (TPL) on solid flat surfaces in low viscous liquids was investigated. The results show that the final length of TPL on homogeneous solid surfaces tend to decrease with the increasing liquid viscosity. For heterogenous solid surfaces, TPL motion on non-stick coal surface is basically the same as that on homogeneous solid surfaces, whereas that on anthracite surface shows an anomalous morphology. By applying the power-law model, the fast and slow spreading stages of bubble on homogeneous surfaces show the universal exponent of b = 1/2 and b = 1/10, respectively. While the exponent for bubble spreading on heterogeneous surface is complicated due to the special surface physico-chemical properties.

Three-dimensional simulation of binary alkane mixture flow in a ballistic cycle of a high-pressure direct fuel injector using a mass transfer cavitation model

A multi-species cavitation model is applied to a high-pressure injection cycle. Results of transient simulations with ballistic needle dynamics are presented. Species segregation in terms of local species demixing in the liquid phase is assessed. Therefore, the mass transfer cavitation model proposed by [101] is adopted and implemented in an incompressible large-eddy simulation flow solver. The model is based on the Rayleigh bubble dynamics equation, Raoult's and Dalton's law, vapor-liquid equilibrium, and mixing rules. It is initially tested on a hydrofoil test case and subsequently applied to a high-pressure injector. A heavier n-dodecane/n-heptane and a lighter n-octane/n-heptane mixture are considered. For both mixtures, essentially the same vortex and vapor structures are encountered. No distinct hysteresis between opening and closing phase of the cycle is present, which is related to a relatively low liquid density of both mixtures. Segregation correlates with the amount of vapor and is most pronounced for cloud cavitation at low needle lift levels and minor for string cavitation at high needle lift levels. It is considerably more pronounced for the heavier than the lighter mixture due to a wide spread of volatilities of n-dodecane and n-heptane. Even for the heavier mixture, segregation is much less pronounced than observed in the immediate environment of a single bubble. This observation is related to the homogeneous mixture approach, by which an averaged effect of segregation over the computational cell is assumed. An Euler-Lagrange approach is proposed for future studies, embedding details of mass transfer over the bubble interface into the CFD code.

JUNO high purity nitrogen plant

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kt low level radioactivity liquid scintillator detector in a laboratory 650 m underground. An excellent energy resolution and a large volume offer exciting opportunities for addressing many important topics in neutrino physics. High purity nitrogen is an important factor to ensure the low background of the JUNO detector. High Purity Nitrogen (HPN) is used for detector purging, pipe cleaning, and scintillator purification, among other things in JUNO. According to JUNO’s requirements, the radon concentration in HPN should be less than 10 μBq/m3. To meet this requirement, A high-purity nitrogen plant with 100 Nm3/h maximum rate was designed and constructed. Low-temperature adsorption technology is used to remove radioactive impurities in nitrogen. High purification efficiency was ensured by using an activated carbon column with high column height-to-diameter ratio. Electrostatic collection and low-temperature enrichment methods are combined to measure radon in nitrogen. After ten days of continuous operation at 50 Nm3/h flux rate, the plant can to reduce the radon concentration in nitrogen from 37.4±1.8μBq/m3 to less than 1.33 μBq/m3. After HPN with flow rate of 50 Nm3/h passing through low-background pipeline (About 1.3 km), the radon concentration of HPN is 5.6±0.6μBq/m3.

Understanding sustainable growth in the face of economic policy uncertainties

AbstractThis paper investigates the impact of economic policy uncertainty (EPU) in China, measured by a news-based index, on the sustainable growth of 2771 Chinese non-financial A-share firms (including 1674 SMEs and 1097 non-SMEs) from 2010 to 2022. We also analyze how green business practices moderate the impact of EPU on firms' sustainable growth. After implying various econometric models, this study finds that EPU has a significant negative effect on the sustainable growth of Chinese firms, which is more pronounced among non-SMEs. Heterogeneity analysis reveals that the negative impact of EPU on CSG is more pronounced in big firms, highly leveraged firms, firms with low liquidity and low financialization in China. We further reveal that this negative impact of EPU stems from trade policy uncertainties. Furthermore, findings reveal that green business activities positively moderate the association between EPU and sustainable growth, and that this moderating impact is more pronounced among SMEs. These findings are consistent with various robustness approaches. This paper provides useful insights for enterprises to improve their sustainable growth in the context of economic policy uncertainties by adjusting their number of employees, board of directors, average age of staffs, financialization level and debt flexibility.

Developing a [formula omitted]Bq/m3 level 226Ra concentration in water measurement system for the Jiangmen Underground Neutrino Observatory

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose low background Liquid Scintillator (LS) detector, was proposed primarily to determine the neutrino mass ordering. To suppress the radioactivity from the surrounding rocks and tag cosmic muons, the JUNO central detector is submerged in a Water Cherenkov Detector (WCD). In addition to being used in the WCD, ultrapure water is used in LS filling, for which the 226Ra concentration in water needs to be less than 50 μBq/m3. To precisely measure the 226Ra concentration in water, a 6.0 μBq/m3226Ra concentration in water measurement system has been developed. In this paper, the detail of the measurement system as well as the 226Ra concentration measurement result in regular EWII ultrapure water will be presented.

La reacción de los hogares ante el repunte de los precios en España y en la UEM

Rationale Faced with the recent inflationary episode, households have employed different strategies to adjust their consumption, saving and labour supply decisions in response to higher prices. This article discusses what those strategies have been and how they have varied based on household characteristics. Takeaways •The strategies most widely used by households to cope with the price increases, both in Spain and in the euro area, were shopping around for better alternatives (e.g. offers) and reducing their saving and spending levels. •Spanish households have resorted to credit and increased their labour supply (by taking a second job or working longer hours) to cushion the impact of higher prices on consumption more than their euro area counterparts. This is especially true among households with low liquidity buffers. •Young people, women, people with a lower educational level and those living in rented housing have showed a greater propensity to work more hours to cope with inflation.