Condensate Fraction Research Articles

Management of de-oiled coffee beans biomass through pyrolysis process: Towards a circular bioeconomy

In this work, we proposed the pyrolysis process for the valorization of de-oiled defective coffee beans (DCB) residual biomass provided by the pressurized fluid extraction (PFE) process after the recovery of coffee oil. The proposal to subsequent thermoconversion of the de-oiled biomasses focuses in an integrated biorefinery concept to obtain value-added products, what fits into the circular bioeconomy strategy. DCB biomasses showed the highest coffee oil recovery yields (∼10%) from the PFE processes and presented yields of the pyrolysis condensate fraction (bio-oil + aqueous fraction) in the range between 53.7% and 59.4%. On the other hand, the yields of biochar and pyrolysis gas increased, with values from 23.6% to 27.3%, and from 17.0% to 19.5%, respectively, when compared to the yields from pyrolysis of the raw DCB. The biochars showed very similar compositions, with HHV between 24.7 and 25.3 MJ kg−1. Overall, the bio-oils showed same constituents with variation in the concentrations of some species detected by GC/MS. Among them, the main classes with such alterations were phenolic compounds and carboxylic acids, in which the relative contents ranged from 19.7% to 39.0% and 11.3–46.1%, respectively. The findings demonstrated the potential of using pyrolysis as a sequential step to add value to the de-oiled DCB biomass remaining after the extraction of coffee oil, which could contribute to a sustainable circular economy with zero waste generation.

Bose–Einstein condensation of two-dimensional spin-1 Cooper pairs in a uniform magnetic field

Bose–Einstein condensation of two-dimensional spin-1 Cooper pairs in a uniform magnetic field is investigated within the framework of quantum statistical mechanics. We derive an exact analytical solution of two-dimensional spin-1 Cooper pairs in a uniform magnetic field, which involves a q-digamma function in mathematics. In two dimensions, it is found that the critical temperature and condensate fraction are monotonically increasing functions of magnetic field B, Landé factor g, and number density σ. Our investigation in two dimensions provides an example of the magnetic-field-tuned insulator-superconductor quantum phase transition.

Time-dependent condensation of bosonic potassium

We calculate the time-dependent formation of Bose–Einstein condensates (BECs) in potassium vapours based on a previously derived exactly solvable nonlinear boson diffusion equation (NBDE). Thermalization following a sudden energy quench from an initial temperature T_mathrm {i} to a final temperature T_mathrm {f} below the critical value and BEC formation are accounted for using closed-form analytical solutions of the NBDE. The time-dependent condensate fraction is compared with available ^{39}K data for various scattering lengths.Graphic

Downstream Torrefaction of Wood Pellets in a Rotary Kiln Reactor—Impact on Solid Biofuel Properties and Torr-Gas Quality

Solid biofuels produced from torrefaction have improved coal-like properties in comparison to raw biofuels, yet ensuring uniform product quality is still a challenge. In this study, downstream torrefaction of wood pellets was performed at temperatures between 200 and 270 °C in a rotary kiln reactor to understand the effect of torrefaction temperature on product quality. The torrefied solid biofuel was compared with dedicated fuel properties defined in ISO/TS 17225-8:2016-12. Based on the results, the optimal temperature for downstream torrefaction was found at temperatures of 230 and 250 °C. Above this temperature, the effect of bulk density superimposes not only the increased net calorific value but also values for mechanical durability, amount of fines, and bulk density of the solid biofuel, which were below the thresholds of the fuel standard. Moreover, increasing process temperatures caused higher heavy metal concentrations in torrefied pellets. The composition of condensable and non-condensable fractions of the torr-gas substantially increased between temperatures of 230 and 250 °C and remained on a similar level at higher temperatures. Thus, the utilization of torr-gas for energy recovery purposes and as a precursor for the recovery of valuable chemicals should be balanced with the quality of the solid biofuel in the aforementioned range of torrefaction temperatures to enable the utilization of torrefaction products at further steps.

Observation of Bose-Einstein condensates of excitons in a bulk semiconductor

An unambiguous observation of the Bose-Einstein condensation (BEC) of excitons in a photoexcited bulk semiconductor and elucidation of its inherent nature have been longstanding problems in condensed matter physics. Here, we observe the quantum phase transition and a Bose-Einstein condensate appearing in a trapped gas of 1s paraexcitons in bulk Cu2O below 400 mK, by directly visualizing the exciton cloud in real space using mid-infrared induced absorption imaging that we realized in a dilution refrigerator. Our study shows that the paraexciton condensate is undetectable by conventional luminescence spectroscopy. We find an unconventionally small condensate fraction of 0.016 with the spatial profile of the condensate well described by mean-field theory. Our discovery of this new type of BEC in the purely matter-like exciton system interacting with a cold phonon bath could pave the way for the classification of its long-range order, and for essential understanding of quantum statistical mechanics of non-equilibrium open systems.

Inlet hydrogenation gas chromatography to predict mass % linear paraffin content

The light condensate fraction obtained from the low temperature Fischer-Tropsch (LT-FT) process is very complex and it is processed further by hydrotreating to produce hydrocarbon products that can be sold as final products. The mass% linear paraffins in some of the final paraffin products is listed as a required specification. Usually gas chromatography equipped with a flame ionisation detector (GC-FID) is used for the analysis of the condensate feeds to estimate the mass% linear paraffins that can be expected in the final products after commercial hydrogenation. This is an important parameter used in the blending of suitable condensate feeds. Due to the complexity of the condensate feeds, significant peak overlap occurs in the GC-FID analysis, making it difficult to accurately estimate the mass% linear paraffin content that will be obtained in the hydrogenated products. Inlet hydrogenation GC-FID analysis simplifies the prediction of the mass% linear content that can be expected in the paraffin product fractions from the analysis of a plant feed since the feed is hydrogenated in the GC inlet before GC-FID analysis. The results from this study showed that sufficient hydrogenation without significant peak tailing can be obtained in the GC inlet when using the appropriate mass and particle size Pd/Al2O3 catalyst with the optimum bed height. Inlet hydrogenation GC-FID analysis simplifies the prediction of the mass% linear content that can be expected in the paraffin product fractions. The method can be implemented on routine GC-FID instrumentation by simply installing an inlet liner containing an appropriate catalyst, that could be re-used at least 20 times, and avoids the purchasing of additional instrumentation and complex data processing and is suitable for commercial process control.

Sulfur containing mixed wastes in anaerobic processing by new immobilized synthetic consortia

Methanogenic biotransformation of unusual substrates (sulfur (S)-containing wastes: non-purified vacuum gas oil, straight-run gasoline fraction (Naphtha), gas condensate, and straight-run diesel fraction) coming from oil industry after their oxidative desulfurization was investigated. Nitrogen-containing wastes (hydrolysates of chicken manure and Chlorella vulgaris biomass) were added as co-substrates to mixture with oil industry wastes. The 100 % conversion of S-organic compounds to inorganic sulfide accumulated in the reaction liquid medium was achieved with simultaneous production of biogas containing high methane percent (greater than 70 %). Polishing of effluents from methane tank was carried out by denitrifying oxidation of ammonium (DEAMOX). The high process efficiency was due to use of original immobilized artificial consortia at the stage of methanogenesis and DEAMOX. This study reveals the real potential in the processing of very complex mixtures of large-scale wastes, usually inhibiting methanogenesis, by developing biocatalysts based on synthetic biology approaches.

Understanding Controlling Factors of Extratropical Humidity and Clouds with an Idealized General Circulation Model

Abstract This paper examines the physical controls of extratropical humidity and clouds by isolating the effects of cloud physics factors in an idealized model. The Held–Suarez dynamical core is used with the addition of passive water vapor and cloud tracers, allowing cloud processes to be explored cleanly. Separate saturation adjustment and full cloud scheme controls are used to consider the strength of advection–condensation theory. Three sets of perturbations to the cloud scheme are designed to test the model’s sensitivity to the physics of condensation, sedimentation, and precipitation formation. The condensation and sedimentation perturbations isolate two key differences between the control cases. First, the sub-grid-scale relative humidity distribution assumed for the cloud macrophysics influences the location and magnitude of the extratropical cloud maxima, which interrupt the isentropic transport of moisture to the polar troposphere. Second, within the model’s explicit treatment of cloud microphysics, re-evaporation of hydrometeors moistens and increases clouds in the lower troposphere. In contrast, microphysical processes of precipitation formation (specifically, the ratio of accretion to autoconversion) have negligible effects on humidity, cloudiness, and precipitation apart from the strength of the large-scale condensation and formation cycle. In addition, counterintuitive relationships—such as cloud condensate and cloud fraction responding in opposing directions—emphasize the need for careful dissection of physical mechanisms. In keeping with advection–condensation theory, circulation sets the patterns of humidity, clouds, and precipitation to first order, with factors explored herein providing secondary controls. The results substantiate the utility of such idealized modeling and highlight key cloud processes to constrain.

Two-site anyonic Josephson junction

Anyons are particles with intermediate quantum statistics whose wavefunction acquires a phase $e^{i\theta}$ by particle exchange. Inspired by proposals of simulating anyons using ultracold atoms trapped in optical lattices, we study a two-site anyonic Josephson junction, i.e. anyons confined in a one-dimensional double-well potential. We show, analytically and numerically, that many properties of anyonic Josephson junctions, such as Josephson frequency, imbalanced solutions, macroscopic quantum self-trapping, coherence visibility, and condensate fraction, crucially depend on the anyonic angle $\theta$. Our theoretical predictions are a solid benchmark for near future experimental quantum simulations of anyonic matter in double-well potentials.

Universal quantum effect of two-body correlation in a weakly interacting Bose gas

Based on the Cornwall-Jackiw-Tomboulis (CJT) effective action approach and the requirement to preserve the Goldstone theorem within two-loop approximation, we study the universal quantum effect, which is related to the two-body correlation, in a homogeneous weakly interacting Bose gas at zero temperature. We find the state equations that provide the condensate fraction, energy density, chemical potential, and sound speed. They are the series expansions of the gas parameter.

Manipulating polariton condensates by Rashba-Dresselhaus coupling at room temperature

Spin-orbit coupling plays an important role in the spin Hall effect and topological insulators. Bose-Einstein condensates with spin-orbit coupling show remarkable quantum phase transition. In this work we control an exciton polariton condensate – a macroscopically coherent state of hybrid light and matter excitations – by virtue of the Rashba-Dresselhaus (RD) spin-orbit coupling. This is achieved in a liquid-crystal filled microcavity where CsPbBr3 perovskite microplates act as the gain material at room temperature. Specifically, we realize an artificial gauge field acting on the CsPbBr3 exciton polariton condensate, splitting the condensate fractions with opposite spins in both momentum and real space. Besides the ground states, higher-order discrete polariton modes can also be split by the RD effect. Our work paves the way to manipulate exciton polariton condensates with a synthetic gauge field based on the RD spin-orbit coupling at room temperature.

Magic Gap Ratio for Optimally Robust Fermionic Condensation and Its Implications for High-T_{c} Superconductivity.

Bardeen-Schrieffer-Cooper (BCS) and Bose-Einstein condensation (BEC) occur at opposite limits of a continuum of pairing interaction strength between fermions. A crossover between these limits is readily observed in a cold atomic Fermi gas. Whether it occurs in other systems such as the high temperature superconducting cuprates has remained an open question. We uncover here unambiguous evidence for a BCS-BEC crossover in the cuprates by identifying a universal magic gap ratio 2Δ/k_{B}T_{c}≈6.5 (where Δ is the pairing gap and T_{c} is the transition temperature) at which paired fermion condensates become optimally robust. At this gap ratio, corresponding to the unitary point in a cold atomic Fermi gas, the measured condensate fraction N_{0} and the height of the jump δγ(T_{c}) in the coefficient γ of the fermionic specific heat at T_{c} are strongly peaked. In the cuprates, δγ(T_{c}) is peaked at this gap ratio when Δ corresponds to the antinodal spectroscopic gap, thus reinforcing its interpretation as the pairing gap. We find the peak in δγ(T_{c}) also to coincide with a normal state maximum in γ, which is indicative of a pairing fluctuation pseudogap above T_{c}.

Dynamics of phase defects trapped in optically imprinted orbits in dissipative binary polariton condensates

We study the dynamics of phase defects trapped in a finite optically imprinted ring lattice in binary polariton condensates, under the influence of the cross interaction (CI) between the condensate fractions in different spin components and the spin-orbit interaction (SOI). In this configuration, we find that a vortex circulates unidirectionally in optically induced orbits because of the Magnus force acting in the polariton fluid and the vortex' angular velocity is influenced by the SOI and CI. Interestingly, in our system, these two interactions can also lead to elongated and frozen phase defects, forming a frozen dark solution with similarity to a dark soliton but with finite size in both spin components. When the dark solution is stretched further to occupy the entire orbit of a condensate ring, the phase defect triggers a snake instability and induces the decay of the dark ring solution. The circulation direction of a single vortex is determined by the Magnus force. This situation is more complex for the group motion of multiple vortices because of significant vortex-antivortex interaction. The collective motion of such vortex constellations, however, is determined by the SOI.

Nonequilibrium phase transition in a driven-dissipative quantum antiferromagnet

A deeper theoretical understanding of driven-dissipative interacting systems and their nonequilibrium phase transitions is essential both to advance our fundamental physics understanding and to harness technological opportunities arising from optically controlled quantum many-body states. This paper provides a numerical study of dynamical phases and the transitions between them in the nonequilibrium steady state of the prototypical two-dimensional Heisenberg antiferromagnet with drive and dissipation. We demonstrate a nonthermal transition that is characterized by a qualitative change in the magnon distribution, from subthermal at low drive to a generalized Bose-Einstein form including a nonvanishing condensate fraction at high drive. A finite-size analysis reveals static and dynamical critical scaling at the transition, with a discontinuous slope of the magnon number versus driving field strength and critical slowing down at the transition point. Implications for experiments on quantum materials and polariton condensates are discussed.

Absence of Heating in a Uniform Fermi Gas Created by Periodic Driving

Ultracold atomic gas provides a useful tool to explore many-body physics. One of the recent additions to this experimental toolbox is the Floquet engineering, where periodic modulation of the Hamiltonian allows the creation of effective potentials that do not exist otherwise. When subject to external modulations, however, generic interacting many-body systems absorb energy, thus posing a heating problem that may impair the usefulness of this method. For discrete systems with bounded local energy, an exponentially suppressed heating rate with the driving frequency has been observed previously, leaving the system in a prethermal state for exceedingly long durations. But for systems in continuous space, the situation remains unclear. Here we show that Floquet engineering can be employed to a strongly interacting degenerate Fermi gas held in a flat box-like potential without inducing excessive heating on experimentally relevant timescales. The driving eliminates the effect of a spin-dependent potential originating from a simultaneous magnetic levitation of two different spin states. We calculate the heating rate and obtain a power-law suppression with the drive frequency. To further test the many-body behavior of the driven gas, we measure both the pair-condensation fraction at unitarity and the contact parameter across the BEC-BCS crossover. At low driving frequencies, the condensate fraction is reduced by the time-dependent force, but at higher frequencies, it revives and attains an even higher value than without driving. Our results are promising for future exploration of exotic many-body phases of a bulk strongly-interacting Fermi gas with dynamically engineered Hamiltonians.

Analytical theory of enhanced Bose–Einstein condensation in thin films

We present an analytically solvable theory of Bose–Einstein condensation (BEC) in thin film geometries. Analytical closed-form expressions for the critical temperature are obtained in both the low-to-moderate confinement regime (where the film thickness L is in the order of microns) as well as in the strong confinement regime where the thickness is in the order of few nanometers or lower. The possibility of high-temperature BEC is predicted in the strong confinement limit, with a square-root divergence of the critical temperature T c ∼ L −1/2. For cold Bose gases, this implies an enhancement up to two orders of magnitude in T c for films on the nanometer scale. Analytical predictions are also obtained for the heat capacity and the condensate fraction. A new law for the heat capacity of the condensate, i.e. C ∼ T 2, is predicted for nano-scale films, which implies a different λ-point behavior with respect to bulk systems, while the condensate fraction is predicted to follow a law.

Thermodynamic modeling of aqueous polyelectrolyte solutions with mixed-valent counterions

Thermodynamic modeling of aqueous polyelectrolyte solutions with salts is of significant interest for many industrial applications. This study applies the polyelectrolyte Nonrandom Two-liquid activity coefficient model to aqueous polyelectrolyte solutions with mixed-valent counterions. A modified Delocalized Binding Theory was proposed to determine the polyion condensation fractions of the mixed counterions. This modified theory accounts for the electrostatic binding of the counterions on the polyion, the dissociation entropy of the counterions, and the electrostatic interactions between the uncondensed ionic species. Given the polyion condensation fractions, the critical value of Manning’s parameter ξ and the amounts of uncondensed polyions and counterions can be calculated along with the activity coefficients of mobile ions. The model successfully correlates experimental data for various aqueous polyelectrolyte systems with mixed-valent counterions.

Improvement of the method of removing asphalt-resin-paraffin deposits to ensure the safety of technological processes

The article deals with the problems of removing asphalt-resin-paraffin deposits in oil wells. Improvement of the method of removing deposits with a solvent is proposed. The parameters of safe operation of oil wells due to the content of asphalt-resin-paraffin deposits were calculated in the framework of the established synergistic effect of the interaction of cavitation factors and non-polar chemical compounds, characterized by the fact that their combined action significantly increases the dissolving and washing ability of the solvent. A method for obtaining a solvent from a fraction of gas condensate with a high content of naphthenic hydrocarbons has been proposed and scientifically substantiated, the use of which ensures an increase in industrial safety during the operation of oil wells. By calculation, a decrease in the value of industrial risk at an oil well after the use of an asphalt-resin-paraffin deposits solvent obtained experimentally is shown.

Efficient neutralization of core ionized species in an aqueous environment.

Core ionization dynamics of argon-water heteroclusters ArM[H2O]N are investigated using a site and process selective experimental scheme combining 3 keV electron irradiation with Auger electron-ion-ion multi-coincidence detection. The formation of Ar 2p-1 vacancies followed by non-radiative decay to intermediate one-site doubly ionized states Ar2+(3p-2)-ArM-1[H2O]N and subsequent redistribution of charge to the cluster environment are monitored. At low argon concentrations the emission of an [H2O]n'H+/[H2O]n''H+ ion pair is the dominant outcome, implying on high efficiency of charge transfer to the water network. Increasing the condensation fraction of argon in the mixed clusters and/or to pure argon clusters is reflected as a growing yield of Arm'+/Arm''+ ion pairs, providing a fingerprint of the precursor heterocluster beam composition. The coincident Auger electron spectra, resolved with better than 1 eV resolution, show only subtle differences and thereby reflect the local nature of the initial Auger decay step. The results lead to better understanding of inner shell ionization processes in heterogeneous clusters and in aqueous environments in general.

A novel approach to analyze pion femtoscopy for particle emitting sources with Bose–Einstein condensation

Quantum correlations at higher-order were measured in lead–lead collisions at the world largest collider, and a substantial suppression was reported while measuring the three and four pions interferences. The fraction of coherence owing to pion generation in collisions of heavy ions at extreme energies can be investigated along with this suppression. We show and examine pions excretion from a dispersion grouping of droplets using Bose–Einstein condensation which influences the multi-pion correlations to study the structure of the sources as well as the peculiarities of the coherence fraction in collisions at higher energy. We surmised that pions appear to be the preeminent contender for coherence fractions in the following sequence and the correlation functions resulted in the creation of a composite phase of partons–hadronic matter. The main contribution of this research is that we explore the sequences of three and four particles correlations as well as the genuine correlations carried out to probe the fraction of pions condensation during the collisions of heavy nuclei employing a granular structured source. We perceived the considerable difference in the normalized correlations functions between two sources at various droplets number and coherence fractions with this unique technique. We also compared our model results to the scientific results and obtained the coherent fraction which is consistent with the experimental data.