Simultaneous Mass Research Articles

Soret and Dufour effects in two-phase boundary layer flow of non-Newtonian and Newtonian fluids with uniform shear strength ratio

BackgroundThis study numerically investigates heat and mass transfer in two-phase boundary layer shear flows, focusing on a non-Newtonian Casson fluid interacting with an adjacent Newtonian fluid under the influence of thermal radiation. By incorporating both Soret and Dufour effects, we examine how temperature gradients influence mass flux and how concentration differences affect energy flux. These coupled effects are essential for applications involving simultaneous heat and mass transport, such as chemical reactors, separation processes, and thermal management systems. MethodsThe analysis explores boundary layer convergence with varying shear intensities, utilizing the MATLAB solver “bvp4c” with appropriate similarity transformations for computational accuracy. The resulting numerical data are presented in graphical form to illustrate the impact of key parameters on flow characteristics. Additionally, variations in the Sherwood number, Nusselt number, and interfacial shear stress are depicted for each fluid across different parameter values. To evaluate the accuracy of our numerical method, we conducted a comparative analysis with the results reported by Weidman and Wang [4] and Wang [2]. This comparison demonstrated an excellent match, confirming the reliability of our approach, as shown in Table 1 and Fig. 2. Significant findingsThe results demonstrate that the fluid temperature increases with the Dufour number, while the concentration rises with the Soret number. Higher Casson parameter values lead to a reduction in interfacial shear stress in both fluids. Furthermore, the Nusselt and Sherwood numbers increase with an enhanced radiation parameter, highlighting the influence of thermal radiation on heat and mass transfer. These insights offer a valuable understanding of flow behavior in systems with coupled thermal and concentration gradients.

Arkenstone - II. A model for unresolved cool clouds entrained in galactic winds in cosmological simulations

Abstract Arkenstone is a new scheme that allows multiphase, stellar feedback-driven winds to be included in coarse resolution cosmological simulations. The evolution of galactic winds and their subsequent impact on the circumgalactic medium are altered by exchanges of mass, energy, momentum, and metals between their component phases. These exchanges are governed by complex, small-scale physical processes that cannot be resolved in cosmological simulations. In this second presentation paper, we describe Arkenstone’s novel cloud particle approach for modelling unresolvable cool clouds entrained in hot, fast winds. This general framework allows models of the cloud–wind interaction, derived from state-of-the-art high-resolution simulations, to be applied in a large-scale context. In this work, we adopt a cloud evolution model that captures simultaneous cloud mass loss to and gain from the ambient hot phase via turbulent mixing and radiative cooling, respectively. We demonstrate the scheme using non-cosmological idealized simulations of a galaxy with a realistic circumgalactic medium component, using the Arepo code. We show that the ability of a high-specific energy wind component to perform preventative feedback may be limited by heavy loading of cool clouds coupled into it. We demonstrate that the diverging evolution of clouds of initially differing masses leads to a complex velocity field for the cool phase and a cloud mass function that varies both spatially and temporally in a non-trivial manner. These latter two phenomena can manifest in the simulation because of our choice of a Lagrangian discretisation of the cloud population, in contrast to other proposed schemes.

Modeling of wood drying process based on machine learning

Drying is a complex process of simultaneous heat, mass, and momentum transport phenomena with continuous phase changes. Numerical modelling is one of the most effective tools to mechanistically express the different physics of drying processes for accurately predicting the drying kinetics and understanding the morphological changes during drying. However, the mathematical modelling of drying processes is complex and computationally very expensive due to multiphysics and the multiscale nature of heat and mass transfer during drying. Physics-informed machine learning (PIML)-based modelling has the potential to overcome these drawbacks and could be an exciting new addition to drying research for describing drying processes by embedding fundamental transport laws and constraints in machine learning models. Based on a comprehensive literature review, this paper presents two types of information: fundamental physics-based information about drying processes and data-driven modelling strategies to develop PIML-based models for drying applications. The current status of physics-based models and PIML-based models and their limitations are discussed. A sample PIML-based modelling framework for drying application is presented. Finally, the challenges of addressing simultaneous heat, mass, and momentum transport phenomena in PIML modelling for optimizing the drying process are presented at the end of this paper.

Defying the D2-law in fuel droplet combustion under gravity

We show both experimentally and theoretically for the first time that the widely used D2-law for describing the shrinking kinetics of a vaporizing droplet is not the true law for single burning droplets under the influence of gravity. Experimentally, the instantaneous diameter D for such a droplet is identified to obey a new kinetic law: Dn decreases linearly with time t, with the exponent n=2.53±0.30−2.69±0.14 for a variety of common liquid fuels such as alkanes and alcohols of low and high boiling hydrocarbons. Theoretically, we develop a phenomenological theory to show n=8/3≈2.67 well capturing the experimental values. The burning rate constant in this new D8/3-law no longer behaves like the thermal diffusivity α of the gas phase but turns into α3ℓ−7/3/g due to the additional inherent fluid-property-determined buoyancy length ℓ under the influence of the gravitational acceleration g. This non-square power law is purely transport determined. It is a consequence of simultaneous momentum, heat, and mass transfer resulted from buoyant convection setup by the blazing flame around the droplet, insensitive to combustion chemistry and detailed reaction kinetics. This study provides not only renewed insights into the multifaceted droplet combustion phenomenon but also possibly new paradigms for a better understanding or characterization of actual fuel droplet combustion processes in normal gravity environments.

Simultaneous energy and mass calibration of large-radius jets with the ATLAS detector using a deep neural network

Abstract The energy and mass measurements of jets are crucial tasks for the Large Hadron Collider experiments. This paper presents a new calibration method to simultaneously calibrate these quantities for large-radius jets measured with the ATLAS detector using a deep neural network (DNN). To address the specificities of the calibration problem, special loss functions and training procedures are employed, and a complex network architecture, which includes feature annotation and residual connection layers, is used. The DNN-based calibration is compared to the standard numerical approach in an extensive series of tests. The DNN approach is found to perform significantly better in almost all of the tests and over most of the relevant kinematic phase space. In particular, it consistently improves the energy and mass resolutions, with a 30% better energy resolution obtained for transverse momenta p T > 500 GeV.

The Analytical Theory of Water Activity in the Paddy Rice Drying Process

Drying involves the evaporation of moisture, accompanied by simultaneous heat transfer, mass transfer, and momentum transfer. While the diffusion law is considered an applicable model for explaining the drying phenomenon, the actual drying process cannot be accurately predicted using an analytical solution with a constant diffusion coefficient. Energy efficiency in the drying process is low due to an insufficient understanding of the mechanisms governing moisture migration from solids to air. The development of drying theory has stalled due to an unsolvable discrepancy between experimental results and analytical results. This study analyzes the effect of the binding energy of moisture in paddy rice on the diffusion coefficient. The theoretical relationship between water activity and drying rate in paddy rice was investigated, and the drying process was successfully explained by analyzing free energy transfer and transition theory. The mechanism of rice grain drying was described using a new theoretical solution for the drying process. These results provide new insights into the development of a scientific evaluation standard for assessing the efficiency of actual drying processes.

A Rare Case of Bilobed Zenker’s Diverticulum and Concurrent Thyroid Mass: A Report and Literature Review

Bilobed Zenker’s diverticulum is rare, with only 6 reported cases. Our patient was a 55-year-old male with bilobed Zenker’s diverticulum, surgically managed with open diverticulectomy with cricopharyngotomy. A thyroid mass found intraoperatively was removed via lobectomy. To our knowledge this is the first case of bilobed Zenker’s diverticulum with simultaneous thyroid mass. Ours is also the first to present successful treatment of this disorder with open diverticulectomy with cricopharyngotomy. A thyroid mass may be masked by a diverticulum, as in our case. It is necessary to weigh risks and benefits when deciding how to surgically treat bilobed Zenker’s diverticulum.

Unidirectional dispersal of blow fly larvae following decomposition fluids from a pig carcass

The decomposition of a body, and the associated gaseous and liquid discharges emanating from it, attract gravid female blow flies which lay their eggs in or on the body. After the eggs have hatched, the emerging larvae start feeding on the body. As decomposition progresses, the blow fly larvae often migrate away, typically in a random manner in search of favourable conditions for pupation. In this paper, we report on a rarely described phenomenon of unidirectional mass migration of blow fly larvae and postulate on the factors which may drive this process. A decomposition trial utilising a 60-kg pig carcass, deployed in the summer months in Table Mountain National Park, Cape Town, South Africa, was conducted in 2022. On the fifth day of the trial, simultaneous unidirectional mass dispersal of blow fly larvae was observed. The larvae moved downhill in a southeasterly direction, following the flow of decomposition fluids oozing out from the pig carcass. The ‘larval migration stream’ had a length of approximately 1.5 m with a width of 40 cm, tapering to 17 cm at the terminal point. The larval migration stream consisted of the larvae of Chrysomya albiceps and Chrysomya chloropyga. This study demonstrates the importance of understanding the timing and pattern of dispersal of post-feeding blow fly larvae in each geographical region. This is crucial as the minimum post-mortem interval can be miscalculated if older immature insects dispersing from the corpse are not considered and collected during crime scene investigations.

Neutron Skins: Weak Elastic Scattering and Neutron Stars

The recently completed PREX-2 campaign measured the density distribution of neutrons in the lead nucleus as a function of momentum transfer (the form factor), confirmed a relatively large extent of the neutrons beyond the protons in the nucleus (the neutron skin), and provided a precise determination of the density of protons and neutrons at the center of a heavy nucleus. In turn, the measured form factor can be related to various nuclear and neutron star properties. The NICER X-ray telescope has inferred the masses and radii of some X-ray pulsars (neutron stars), although complications arise when determining these quantities independently. Further improvements in NICER have enabled simultaneous mass–radius determinations that had not previously been possible. During the next decade, measurements in astrophysics, gravitational-wave astronomy, and nuclear physics are expected to provide a wealth of more precise data. In this review, we present an overview of the current state of neutron skin measurements and offer insights into prospects for the future.

Development and validation of a sensitive and simultaneous liquid chromatography tandem mass spectrometry method for the determination of eight phytocannabinoids in various CBD products

In this study, we developed and validated a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of eight phytocannabinoids in various cannabidiol (CBD) products from Japanese market. This method was combined with electrospray ionization in positive mode and sample preparation with QuEChERS. Three types of commercial products such as honey, chocolate, and gummies were used to perform accurate quantification with unified protocol of LC-MS/MS and QuEChERS. The limit of detection and quantification were 5–20 µg g−1 and 10–40 µg g−1, respectively. Reproducibility was ensured using matrices free of target foods, resulting in an accuracy within ±10 % and a precision with a relative standard deviation of less than 5 % for all targets. Finally, this analytical method was applied to 8 series of commercial samples from the Japanese market. This unified protocol will serve as a reference as an official method in Japan.

Simultaneous Native Mass Spectrometry Analysis of Single and Double Mutants To Probe Lipid Binding to Membrane Proteins.

Lipids are critical modulators of membrane protein structure and function. However, it is challenging to investigate the thermodynamics of protein-lipid interactions because lipids can simultaneously bind membrane proteins at different sites with different specificities. Here, we developed a native mass spectrometry (MS) approach using single and double mutants to measure the relative energetic contributions of specific residues on Aquaporin Z (AqpZ) toward cardiolipin (CL) binding. We first mutated potential lipid-binding residues on AqpZ, and mixed mutant and wild-type proteins together with CL. By using native MS to simultaneously resolve lipid binding to the mutant and wild-type proteins in a single spectrum, we directly determined the relative affinities of CL binding, thereby revealing the relative Gibbs free energy change for lipid binding caused by the mutation. Comparing different mutants revealed that W14 contributes to the tightest CL binding site, with R224 contributing to a lower affinity site. Using double mutant cycling, we investigated the synergy between W14 and R224 sites on CL binding. Overall, this novel native MS approach provides unique insights into the binding of lipids to specific sites on membrane proteins.

Membrane role in heat and mass transfer resistance distribution and performance of hollow fiber membrane contactor for SGMD desalination

Hollow fiber membrane contactor (HFMC) is the core device of heat mass exchange between seawater solution and sweeping air in sweeping gas membrane distillation (SGMD) desalination. In order to reveal the distribution of heat and mass transfer resistance on feed solution side, porous membrane side and sweeping air side, a mathematical model considering the simultaneous heat mass transfer and water vapor diffusion mechanism in the membrane pores was established for the cross-flow HFMC. The simulation results of the model were compared with experimental results and literature results. Comparison shows that the deviation of simulation results of the model is less than 13.4 %, which verifies the accuracy and reliability of the simulation results. Influences of the main structural characteristics of porous membrane on the resistance distribution of heat and mass transfer, efficiency and membrane flux were explored. Air side dominates the heat transfer process, while the membrane side accounts for less than 39 % of the total heat transfer resistance for the main range of membrane microstructure parameters investigated. The mass transfer is controlled by the porous membrane except for thin membrane with a thickness of less than 100 μm. Membranes with porosity above 0.8 and as thin as possible can achieve better mass transfer efficiency and freshwater flux. Increasing mean pore diameter has a strong promotion effect on the increase of membrane flux before it reaches 150 nm, and beyond this critical value, the water vapor diffusion mechanism changes from Knudsen collision to molecular collision. Effects of different operating parameters and membrane microstructure parameters on air temperature distribution and humidity distribution were also analyzed.

Simultaneous trace mass and quantity of airborne microplastics based on electromagnetic heating-pyrolysis-mass spectrometry, taking surgical face masks as an example

Microplastics (MPs) in the atmosphere have attracted global concern due to their potential threats to human health. However, the current rapid analytical method for airborne MPs is insufficient, which hinders a comprehensive understanding of their environmental risks. In recent years, the disposable face masks have emerged as a new source of airborne MPs. There are significant knowledge gaps regarding MPs from mask, including detection methods, formation mechanisms, and environmental abundance. This study presented a novel analytical approach for the rapid detection of airborne MPs using the electromagnetic heating-pyrolysis-mass spectrometry (Eh-Py-MS). To validate this method, surgical face masks were employed as an illustrative example. The mass-related quantification of MPs was realized based on the Eh-Py-MS. By employing a conversion model of mass, size, and density, simultaneous assessment of both mass and quantity of MPs was realized. The recovery rates were in the range of 86.6%–111.6% and the precision (RSD) was 8.4%, which was sufficient for rapid quantification. Results showed that the simultaneous tracing of mass and quantity of airborne microplastics could be successfully achieved through the developed method. Furthermore, the formation mechanism of MPs in surgical masks under UV exposure was also investigated to address the knowledge gap of masks MPs. Results indicated that surgical masks could be a neglected source of airborne microplastics in the environment. This study aims to provide valuable insights for the rapid assessment of airborne MPs in the environment.

Simultaneous detection of testosterone, nandrolone, and boldenone esters in dried blood spots for doping control in sports by liquid chromatography-tandem mass spectrometry.

Testosterone, nandrolone, and boldenone, which are listed as doping substances on the World Anti-Doping Agency Prohibited List, are mostly available commercially in esterified forms. Isotope ratio mass spectrometry (IRMS) represents a key tool for identifying these substances, as they are hydrolyzed and discharged in the urine as pseudo-endogenous substances. However, IRMS, which comprises a complicated process, cannot achieve the direct detection of steroid esters in blood samples. These substances can be detected using dried blood spots (DBSs), reducing the impact of esterase hydrolysis. Here, a simultaneous liquid chromatography-tandem mass spectrometry method for detecting 28 steroid (13 testosterone, nine nandrolone, and six boldenone) esters was developed using three DBS types of samples, including a cellulose paper and polymer. The substances were first derivatized with methyloxime to increase their sensitivities (the limits of detection were <0.1-0.4, <0.1-0.9, and <0.1-0.9ng/mL for the testosterone, nandrolone, and boldenone esters, respectively). Further, the DBS absorbents were verified since the effect of interferences depended on it. Next, a study involving seven participants was conducted to detect intramuscularly administered testosterone enanthate (100 mg). Polymer and cellulose papers were used to collect blood from their upper arms and fingertips, respectively, and testosterone enanthate was identified and detectable at both blood-collection sites for up to 144 and 216 h, respectively. Furthermore, testosterone enanthate was detectable in the DBS samples stored under refrigeration after 6 months, indicating the stable nature of DBS.

Simultaneous mass spectrometric quantification of trace amines, their precursors and metabolites

ObjectivesTrace amines are powerful neuromodulators influencing the release and reuptake of catecholamines. These low concentrated endogenous amines impact mood, cognition, and hormone regulation. Dysregulation of trace amines have been associated with a variety of diseases, such as schizophrenia, Parkinson’s disease, migraine, depression and more. Succesfull simultaneous quantification of trace amines, their precursors and metabolites would benefit both research and patient care. Since these compounds have various functional groups and are present in biological matrices with large concentration difference, their simultaneous quantification is an analytical challenge. Our goal was to develop a highly sensitive LC-MS/MS assay to simultaneously quantify trace amines, their precursors and metabolites in plasma. MethodsOur method is based on a simple two-step in-matrix derivatization protocol: propionic anhydride (PA) and 3-Ethyl-1-[3-(dimethylamino)propyl]carbodiimide (EDC) in combination with 2,2,2-trifluoroethylamine (TFEA) followed by online solid phase extraction combined with LC-MS/MS. Fifteen metabolites can be measured simultaneously, three precursors, eight trace amines and four metabolites. Validation of this method was performed according to international validation guidelines. The pre-analytical stability of trace amines was assessed. ResultsThis novel method was successful in quantifying trace amines, their precursors, and metabolites in plasma. Using just 50 µl human plasma, we were able to accomplish limit of quantification for 2-phenylethylamine and N-methyl-phenylethylamine of 0.2 nmol/L and 0.1 nmol/L for tyramine and n-methyltyramine. Inter-and intra-assay imprecision was < 15 % for all analytes. Stability assessment showed susceptibility of certain trace amines e.g. 2-phenylethylamine and N-methyl-phenylethylamine to enzymatic degradation in plasma. The addition of the monoamine oxidase inhibitor pargyline to plasma prevented this enzymatic degradation. ConclusionsWe developed a novel LC-MS/MS method that1) uses a new double derivatization technique, 2) is automated with online SPE, 3) uses far less sample volume then previous methods and 4) detects more components in the same sample (eight trace amines, three precursors, and four metabolites) with high specificity and selectivity. Furthermore, addition of MAO A/B inhibitor prevents degradation and guarantees more accurate quantification of trace amines.

Silver-Loaded Chabazite in Ethanol-to-Hydrocarbon Process-Operando FT-IR and UV-Vis Spectroscopic Studies.

The ethanol dehydration process is studied regarding protonic and Ag-loaded chabazite zeolite in advanced FT-IR and UV-vis operando spectroscopic studies with simultaneous mass spectroscopy and gas chromatography analyses of products. The spectroscopic investigation provides information on the species formed on the surface of catalysts, while mass spectrometry and gas chromatography methods identify the desorbed products. These studies are also supported by spectroscopic, chromatographic, and thermogravimetric analyses of coke species formed over the catalyst's surface during ethanol conversion. The Ag-chabazite catalyst shows higher selectivity for ethylene and propylene; the slower formation of coke species; and, thus, a longer lifetime.

Shrinkage properties of porous materials during drying: a review

The shrinkage characteristic of porous materials is an important consideration in the drying process, as it can significantly impact the texture of the dried product and energy utilization. This phenomenon is influenced by numerous factors, including the structure of the cells, drying conditions, and the glass transition temperature. To gain a deeper understanding of the drying process, it is necessary to develop theoretical models that account for the simultaneous heat and mass transfer processes at the cellular level, as well as simulation tools to analyze the associated changes in drying morphology. In this paper, we highlight several key factors affecting shrinkage during the drying of porous materials, and also outline drying modeling, morphological simulation, and drying technology design considerations to provide guidance for improving the drying quality of porous materials as well as energy conversion efficiency.

Integrating direct messaging with flood alerts and warnings: Insights into effectiveness from a registered public user population

AbstractDirect messaging involving simultaneous mass transmission of brief text or voice messages to large numbers of recipients has become a frontline method in flood hazard communications. Messages are intended to serve as cues, drawing recipients' attention to changing conditions, yet the actual effectiveness of direct messaging among recipient groups remains under‐examined. This article considers direct messaging within the Floodline public flood warning service in Scotland, implemented by the Scottish Environment Protection Agency (SEPA). Within Floodline, messaging is integrated with alerting and warning information, termed straightforwardly ‘Flood Alerts’ and ‘Flood Warnings’. Collaborating with SEPA, we conducted an online questionnaire survey of registered Floodline direct messaging recipients. In this article, our analysis focusses specifically on responses to three open‐ended questions included in this survey, with an iterative qualitative coding approach employed to interpret themes of meaning from the question responses. This analysis gives a clear indication that recipients value Floodline and direct messaging. However, there are also questions raised over the utility of Flood Alerts and related messaging, which we elaborate in the findings and discussion, along with the scope for adding content, linking to other information, and developing closer relationships. Changes being developed by SEPA align with several of these findings.

High-throughput assay to simultaneously evaluate activation of CYP3A and the direct and time-dependent inhibition of CYP3A, CYP2C9, and CYP2D6 using liquid chromatography-tandem mass spectrometry

In the early stages of drug discovery, adequate evaluation of the potential drug–drug interactions (DDIs) of drug candidates is important. Several CYP3A activators are known to lead to underestimation of DDIs. These compounds affect midazolam 1'-hydroxylation but not midazolam 4-hydroxylation. We used both metabolic reactions of midazolam to evaluate the activation and inhibition of CYP3A activators simultaneously. For our CYP inhibition assay using cocktail probe substrates, simultaneous liquid chromatography-tandem mass spectrometry monitoring of 1'-hydroxymidazolam and 4-hydroxymidazolam for CYP3A was established in addition to monitoring of 4-hydroxydiclofenac and 1'-hydroxybufuralol for CYP2C9 and CYP2D6. The results of our cocktail inhibition assay were well correlated with those of a single inhibition assay, as were the estimated inhibition parameters for typical CYP3A inhibitors. In our assay, a proprietary compound that activated midazolam 1'-hydroxylation and tended to inhibit 4-hydroxylation was evaluated along with known CYP3A activators. All compounds were well characterised by comparison of the results of midazolam 1'- and 4-hydroxylation. In conclusion, our CYP cocktail inhibition assay can detect CYP3A activation and assess the direct and time-dependent inhibition potentials for CYP3A, CYP2C9, and CYP2D6. This method is expected to be very efficient in the early stages of drug discovery.

Modeling of Triphenyl Phosphate Surfactant Enhanced Drying of Polystyrene/p-Xylene Coatings Using Artificial Neural Network

The drying process of polymeric coatings, particularly in the presence of surfactants, poses a complex challenge due to its intricate dynamics involving simultaneous heat and mass transfer. This study addresses the inherent complexity by employing Artificial Neural Networks (ANNs) to model the surfactant-enhanced drying of poly(styrene)-p-xylene coatings. A substantial dataset of 16,258 experimentally obtained samples forms the basis for training the ANN model, showcasing the suitability of this approach when ample training data is available. The chosen single-layer feed-forward network with backpropagation adeptly captures the non-linear relationships within the drying data, providing a predictive tool with exceptional accuracy. Our results demonstrate that the developed ANN model achieves a precision level exceeding 99% in predicting coating weight loss for specified input values of time, surfactant amount, and initial coating thickness. The model’s robust generalization capability eliminates the need for additional experiments, offering reliable predictions for both familiar and novel conditions. Comparative analysis reveals the superiority of the ANN over the regression tree, emphasizing its efficacy in handling the intricate dynamics of polymeric coating drying processes. In conclusion, this study contributes a valuable tool for optimizing polymeric coating processes, reducing production defects, and enhancing overall manufacturing quality and cost-effectiveness.