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This paper presents BubbleID, a sophisticated deep learning architecture designed to comprehensively identify both static and dynamic attributes of bubbles within sequences of boiling images. By amalgamating segmentation powered by Mask R-CNN with SORT-based tracking techniques, the framework is capable of analyzing each bubble's location, dimensions, interface shape, and velocity over its lifetime and capturing dynamic events such as bubble departure. BubbleID is trained and tested on boiling images across diverse heater surfaces and operational settings. This paper also offers a comparative analysis of bubble interface dynamics prior to and post-critical heat flux conditions. [ABSTRACT FROM AUTHOR]

The liquid-to-vapor transition can occur under unexpected conditions in nanopores, opening the door to fundamental questions and new technologies. The physics of boiling in confinement is progressively introduced, starting from classical nucleation theory, passing through nanoscale effects, and terminating with the material and external parameters that affect the boiling conditions. The relevance of boiling in specific nanoconfined systems is discussed, focusing on heterogeneous lyophobic systems, chromatographic columns, and ion channels. The current level of control of boiling in nanopores enabled by microporous materials such as metal organic frameworks and biological nanopores paves the way to thrilling theoretical challenges and to new technological opportunities in the fields of energy, neuromorphic computing, and sensing. [ABSTRACT FROM AUTHOR]

The production of methane in coastal sediments and its release to the water column is intensified by anthropogenic eutrophication and bottom water hypoxia, and it is still uncertain whether methane emissions to the atmosphere will be enhanced. Here, we assess seasonal variations in methane dynamics in a eutrophic, seasonally euxinic coastal basin (Scharendijke, Lake Grevelingen). In-situ benthic chamber incubations reveal high rates of methane release from the sediment to the water column (74–163 mmol m−2 d−1) during monthly measurements between March and October 2021. Comparison of these in-situ total benthic methane fluxes and calculated diffusive fluxes point towards a major role for ebullition. In spring and fall, when the water column was oxic, microbial removal of dissolved methane occurred aerobically in the bottom water. In summer, in contrast, dissolved methane accumulated to concentrations of up to 67 μmol L−1 below the oxycline. Shifts in δ 13C–CH 4 and δ D-CH 4 towards higher values and the abundant presence of methane oxidizing bacteria point towards removal of methane around the oxycline, likely through both aerobic and anaerobic pathways, with the latter possibly linked to iron oxide reduction. Shifts in δ 13C–CH 4 and δ D-CH 4 to lower values above the oxycline indicate that bubble dissolution contributed to dissolved methane. Methane emissions to the atmosphere were observed in all seasons with the highest, in-situ measured diffusive fluxes (1.2 mmol m−2 d−1) upon the onset of water column mixing at the end of summer. Methane release events during the measurement of in-situ water-air fluxes and model calculations point towards a flux of methane to the atmosphere in the form of bubbles, which bypass the microbial methane filter. The model calculations suggest a potential year-round ebullitive methane flux between 30 and 120 mmol m−2 d−1. We conclude that methane emissions from eutrophic coastal systems may be much higher than previously thought because of ebullition. [ABSTRACT FROM AUTHOR]

• New data of jet impingement boiling on surface modified metal foam were obtained. • Effects of metal foam wettability on boiling heat transfer were analyzed. • Influence on bubble dynamics behavior was analyzed. • New heat transfer coefficient correlation considering wettability was developed. Wettability may have significant influence on jet impingement boiling on metal foam, but the effect mechanism of metal foam wettability remains unclear. In this study, the boiling heat transfer characteristics of distributed jet array impingement on hydrophobic and hydrophilic metal foam covers were experimentally researched and compared with those on uncoated metal foam covers to analyze the influence of wettability. The experimental conditions cover contact angles of 14.0–158.7°, pore densities of 20–40 PPI, porosities of 92 %-97 %, thicknesses of 3.0–5.0 mm, and jet velocities of 0.5–4.0 m·s−1. The results show that, the obtained maximum heat flux and maximum heat transfer coefficient are up to 538.1 W cm−2 and 57.9 Kw m−2 K−1, respectively; the hydrophobic metal foam cover has a 4.8 K lower surface superheated degree at the onset of nucleate boiling, but a 7.5 % lower maximum heat transfer coefficient compared with the uncoated one; the hydrophilic metal foam cover shows a less deterioration after the departure from nucleate boiling but a 5.3 K higher surface superheated degree at the onset of nucleate boiling than those of the uncoated one. A new correlation for boiling heat transfer coefficients was developed with a mean relative error of 9.75 %. [ABSTRACT FROM AUTHOR]

Nanofluid was frequent technique which solved microscale heat and mass transport problems to intensify pool boiling heat transfer. This paper had investigated the effect of nanofluid, ultrasonic field and ribs surfaces on cooperative heat transfer enhancement in pool boiling. A two-step method was applied to prepare Al2O3 nanofluids of different kinds of concentrations and diameters. Group experiments were examined the influences of nanofluid concentration and diameter, ultrasonic power and distance and rib surface type on heat transfer characteristics, respectively. The heat flux and convection heat transfer coefficient were used the performance parameters. The results showed that the concentration and diameter of the Al2O3 nanofluid effected the heat transfer performance on the pool boiling. The Al2O3 nanofluid with an average diameter of 80 nm had the most significant enhancement effect on the pool boiling heat transfer performance, but the Al2O3 with a diameter of 30 nm had the weakest enhancement effect, when the concentration of Al2O3 nanofluid was 0.01 wt%. Meanwhile, the generated acoustic streaming effect and cavitation effect by ultrasonic field can promote the energy accumulation, rupture and regeneration of the bubbles at low superheat stage on nanofluid pool boiling. The heat transfer coefficient (HTC) gradually enhances as the ultrasonic field changes. At an ultrasonic power of 528 W and a distance of 50 mm, the nanofluid pool boiling increased by 44.34% compared to no ultrasonic field HTC. Compared with No rib, the boiling point of the Al2O3 nanofluidic pool boiling of Rib II was reduced by 2°C under the ultrasonic field. The nanofluid pool boiling with ultrasonic field of p = 528 W and Rib II had the best heat transfer effect, and HTC improved more than 50%. This is due to the addition of more nucleation points for bubbles on the heated surface of the Rib II. [ABSTRACT FROM AUTHOR]

Compared with the traditional mechanical knitting needle, the tubular magnetic suspension knitting needle has the advantages of no friction and flexible control. But the highspeed reciprocating motion of the needle needs to consume a lot of power. The winding temperature is difficult to suppress. The heat dissipation performance becomes the main obstacle restricting the power improvement. In this paper, an integral tubular electric knitting needle is proposed and studied. The heat dissipation area of the needle is increased by the annular thermosyphon in the motor housing. The heat dissipation performance is carefully studied by experiments, and the results show that the heat dissipation performance is obviously improved compared with the original design. Under the power of 17 W, after the annulus thermosyphon is started, the maximum temperature of the winding can be suppressed at about 107 °C. Boiling occurs only at certain points on the surface of the winding, which is related to the structural asymmetry in the winding manufacturing and epoxy injection processes. The heat dissipation performance is best when the winding is located at the bottom of the motor. The axial temperature difference is within 15 °C while the circumferential temperature difference is within 4 °C. [ABSTRACT FROM AUTHOR]

The article analyses the degree of water superheating with respect to the liquid-vapour equilibrium line in experiments on the micro-explosion of a composite droplet comprised of two immiscible liquids. The analyses were carried out for water-in-fuel drops under conditions of high-power heating. This degree is compared with the mechanical effect of droplet decay, involving the formation of daughter droplets. Our attention was drawn to the smallness of the degree of superheating preceding the decay. A model of the boiling up of such a droplet is constructed taking into account the sources of premature boiling up of water inherent in micro-explosive experiments. The dependencies of the boiling up temperature of water on the heating rate obtained in the model turned out to be in accordance with the experimental data across a wide range of heating rates. A hypothesis about the local superheating of the transition layer, which is not detected in the experiment, is formulated. Thus, a step has been taken to clarify the essence of the mismatch of the degree of superheating of water recorded by macroscopic equipment along with a completely satisfactory generation of daughter droplets serving as the basis for advanced fuel technology. [ABSTRACT FROM AUTHOR]

ABSTRACT Roasted peanuts (OPs) are more often used in daily life than boiled peanuts (BPs); the main reason may be related to the pleasurable flavor in OPs. This study comparatively investigated the effects of boiling and roasting on nutritional components contents, taste, and aroma to reveal the advantages of roasting in terms of the nutrition and flavor of peanuts. Results showed that boiling increased fat content to 54.47% of peanuts, diluted or reduced sugar content to an undetectable level, noticeably changed the contents of poly/monounsaturated fatty acids, and significantly decreased the content of free amino acid (FAA, 1.05 mg/g peanuts) in peanuts. Roasting simply decreased the contents of sugar and FAA to 2.78 and 1.82 mg/g peanuts, respectively. Compared with roasting, boiling had more discernible effects on fatty acids and FAAs. Both BPs and OPs have good dietary lipid quality. In terms of flavor, OPs had more FAAs (2 types) that contributed remarkably to the taste of peanuts than BPs (0 types), more volatile substances (40 types) than BPs (12 types), and a higher number of key volatile aroma components (8 types) than BPs (3 types). That is, roasting induced a relatively small effect on nutritional components and gave peanuts a richer taste and stronger aroma than boiling; therefore, roasting is an ideal peanut processing method. This study proved the different changes in peanuts caused by boiling and roasting on a material basis and corroborated the irreplaceability of roasting in peanut processing. [ABSTRACT FROM AUTHOR]

The heat transfer limit of heat pipes is investigated by pool boiling experiments in a standard apparatus with a capillary layer placed on a copper tube. The capillary layer is a hollow cylinder made of bronze with a wall thickness of 2 mm and the test fluids are methanol and n‐pentane. The setting is comparable to high‐flux tubes already investigated in the literature. In dependence on the heat flux, three to four sections with different characteristics are identified. Compared to plain copper tubes, the heat transfer is partially increased by a factor of 12 until the limit is reached at around 70 kW m−2. [ABSTRACT FROM AUTHOR]

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This paper presents a model-based PID tuning method for a reactor used in microwave-assisted chemistry. The reactor is equipped with a solid-state source of microwaves and a PID controller capable of increasing or decreasing the delivered microwave power to maintain the reacting substances at the desired temperature. The model has the form of an algorithm applied in numerical simulations of two simultaneous processes: heating a substance by absorbing microwave radiation and cooling it by dissipating heat to the surroundings. It has proven its suitability for tuning the PID controller in a time-efficient manner. Despite some noticeable inaccuracies, the presented approach easily finds PID coefficients that result in stable and repeatable controller operation. In this way, significant time savings can be achieved, as well as minimizing the risks associated with, for example, boiling liquid spills. The article demonstrates that a carefully designed, but still relatively simple, model can yield significant benefits in tuning PID controllers. [ABSTRACT FROM AUTHOR]

ABSTRACT The oxidation of 5,5′‐(methylene)bis(6‐hydroxy‐1,3‐dimethylpyrimidine‐2,4(1H,3H)‐dione) monopiperidinium salts with Mn(OAc)3•2H2O was carried out in boiling MeCN, producing 2,4,9,11‐tetramethyl‐2,4,9,11‐tetraazadispiro[5.0.57.16]tridecane‐1,3,5,8,10,12‐hexaones in high yields. A similar reaction using 4,4′‐(methylene)bis(1,2‐diphenylpyrazolidine‐3,5‐dione)s gave 2,3,8,9‐tetraphenyl‐2,3,8,9‐tetraazadispiro[4.0.46.15]undecane‐1,4,7,10‐tetraones in good yields. The structure determination and the reaction mechanism for the formation of the unique tetraazadispiro(cyclopropane)s are discussed. [ABSTRACT FROM AUTHOR]

Reservoirs are an important source of methane (CH4) emissions, but the relative contribution of CH4 ebullition and diffusion fluxes to total fluxes has received little attention in the past. In this study, we systematically monitored the CH4 fluxes of nine cascade reservoirs (Dahejia, Jishixia, Huangfeng, Suzhi, Kangyang, Zhiganglaka, Lijiaxia, Nina, and Longyangxia) in the upper reaches of the Yellow River in the dry (May 2023) and wet seasons (August 2023) using the static chamber gas chromatography and headspace equilibrium methods. We also simultaneously measured environmental physicochemical properties as well as the abundance of methanogens and methanotrophs in sediments. The results showed the following: (1) All reservoirs were sources of CH4 emissions, with an average diffusion flux of 0.08 ± 0.05 mg m−2 h−1 and ebullition flux of 0.38 ± 0.41 mg m−2 h−1. Ebullition flux accounted for 78.01 ± 7.85% of total flux. (2) Spatially, both CH4 diffusion and ebullition fluxes increased from upstream to downstream. Temporally, CH4 diffusion flux in the wet season (0.09 ± 0.06 mg m−2 h−1) was slightly higher than that in the dry season (0.08 ± 0.04 mg m−2 h−1), but CH4 ebullition flux in the dry season (0.38 ± 0.48 mg m−2 h−1) was higher than that in the wet season (0.32 ± 0.2 mg m−2 h−1). (3) qPCR showed that methanogens (mcrA gene) were more abundant in the wet season (5.43 ± 3.94 × 105 copies g−1) than that in the dry season (3.74 ± 1.34 × 105 copies g−1). Methanotrophs (pmoA gene) also showed a similar trend with more abundance found in the wet season (7 ± 2.61 × 105 copies g−1) than in the dry season (1.47 ± 0.92 × 105 copies g−1. (4) Structural equation modeling revealed that the ratio of mcrA/pmoA genes, water N/P, and reservoir age were key factors affecting CH4 ebullition flux. Variation partitioning further indicated that the ratio of mcrA/pmoA genes was the main factor causing the spatial variation in CH4 ebullition flux, explaining 35.69% of its variation. This study not only reveals the characteristics and influencing factors of CH4 emissions from cascade reservoirs on the Qinghai Plateau but also provides a scientific basis for calculating fluxes and developing global CH4 reduction strategies for reservoirs. [ABSTRACT FROM AUTHOR]

Heat exchange on a heat-stressed surface and the critical heat flow from it in the process of cooling this surface by a system of distributed impact submerged microjets of a dielectric liquid, depending on the velocity of these jets, were investigated experimentally for the case where the initial subcooling of the liquid in the jets to the saturation temperature comprises 40 ± 2°C. The experiments were conducted for 36 jets of the HFE-7100 dielectric liquid with an initial diameter of 174 μm, outflowing from the nozzles positioned at a distance of 1 mm from a cooling surface. It was established that the heat transfer coefficients of this surface and the critical heat flow from it are determined by the velocity of the jets, acting on the surface, and the initial subcooling of the cooling liquid, and that they are much larger than those in the case of pool boiling of the cooling liquid on the surface and in the case of its cooling by a single jet of a liquid with a small subcooling to the saturation temperature. [ABSTRACT FROM AUTHOR]

The upcoming energy scarcity problem has driven research toward developing energy-efficient two-phase heat exchangers essential for various cooling applications. This research is rooted in the principles of pool boiling, essential for effective heat transfer in various heat exchangers. A well-known reported problem in heat exchangers is the dry-out phenomena of heated surfaces due to bubble coalescence. To tackle this undesirable problem, an innovative technique has been introduced in this study, which involves the shearing of bubbles through liquid jet impingement over the heated surface. The study has been carried out in a two-dimensional domain numerically, in the wall superheat range of 9–16 K. To study the underlying physics involved in this pool boiling phenomenon, the bubble dynamics parameters such as departure frequency, bubble diameter, cold spot (bubble base) temperature, and vapor volume fraction have been analyzed. The results show that with the jet shearing effect, a maximum enhancement of 25% in heat transfer rate is observed at higher wall superheat. The investigation also highlights that the liquid jet enhances vapor volume fraction, indicating enhanced steam generation, particularly an enhancement of 27% observed at elevated wall superheat. An early onset necking effect is also observed with the shearing effect, which leads to the formation of smaller bubbles with higher departure frequencies. This study is a benchmark to the fundamental physics of enhancing two-phase heat transfer through bubble shearing, offering promising insights for energy conservation in two-phase heat exchanger design, particularly within the context of pool boiling. [ABSTRACT FROM AUTHOR]

A deeper understanding of the post-impact phenomenology of droplets on cold surfaces is crucial for comprehending and developing anti-icing surfaces for various applications. In the present study, a systematic experimental investigation has been done in a controlled environment with a wide range of subcooled surface temperatures ( T s ∼ 1 ° C − 25 ° C), slightly over the freezing point of water. The inertia force dominates during the spreading phase, and the time for maximal spreading is independent of the surface temperature. However, surface temperature has a major impact on the recoiling phase and governs the post-impact outcome. During the receding phase, the dynamic receding angle varies drastically and is also found to be strongly dependent on surface temperature. It is proposed that the micro-cavity condensation induced water bridge formation and viscous dissipation critically influences the receding dynamics. The retraction becomes partial retraction and finally pins at low temperatures with an enhanced retraction time, thus aiding the proposed mechanism. An empirical relationship is found for the average receding contact angle as a function of surface temperature. A scaling relation for retraction time is proposed that takes into account both the transient and surface temperature dependent variation of receding contact angle variation and the changes in thermophysical properties of the fluid. A theoretical framework has been proposed to predict the pinning to bouncing regimes for drop impact over subcooled superhydrophobic surfaces. The postulated scaling relation and prediction models are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Subcooled nucleate flow boiling encompasses intricate simultaneous condensation and evaporation processes. It involves thin liquid microlayers trapped beneath growing bubbles, enabling high heat and mass transfer with fluxes exceeding 1 MW/m2. Understanding microlayer contribution to bubble growth is pivotal for developing reliable boiling models. Unlike previous studies, we account for condensation effects, important in the context of subcooled boiling regime, in estimating microlayer contribution by simultaneously obtaining microlayer dynamics from thin-film interferometry and whole-field temperature from rainbow schlieren deflectometry. We establish that the microlayer evaporation significantly influences bubble growth in flow boiling, contributing up to 60% (in growth phase) in the present study. [ABSTRACT FROM AUTHOR]

The effect of biphilic surfaces on subcooled flow boiling in a horizontal rectangular duct was investigated. Biphilic surfaces were created on an aluminum alloy substrate in the form of juxtaposed Hydrophobic (HPo) and Hydrophilic (HPi) transverse strips. In this regard, two different testing samples with strip widths of 10 and 18 mm were prepared, named pattern I and pattern II, respectively. Using Deionized Water (DIW), the experiments were performed with the two mentioned biphilic patterns and a plain surface. Finally, different cases were compared, and the results were interpreted. The results showed that the biphilic surfaces improve the Heat Transfer Coefficient (HTC) and cause boiling to be initiated at a lower wall temperature. In this regard, pattern I and pattern II represent 22 and 40% improvement in HTC, and boiling initiates 31 and 33.5 °C sooner compared to the plain surface, respectively. In addition, the experiments were also conducted with an Ethylene Glycol/Water mixture (EG/W) in the same manner. The results revealed that EG/W represents smaller HTC values for all cases and shifts the boiling points to higher wall temperatures compared to DIW. It is worth mentioning that the major amount of this HTC reduction is occurred in the single-phase area, in lower wall temperatures. [ABSTRACT FROM AUTHOR]

The precise design of heat exchangers in automobile air conditioning systems for more sustainable electric vehicles requires an enhanced assessment of CFD mechanistic models for the subcooled boiling flow of pure eco-friendly refrigerant. Computational Multiphase Flow Dynamics (CMFDs) relies on two-phase closure models to accurately depict the complex physical phenomena involved in flow boiling. This paper thoroughly examines two-phase CMFD flow boiling, incorporating sensitivity analyses of critical parameters such as boiling closures, momentum closures, and population balance models. Three datasets from the DEBORA experiment, involving vertical pipes with subcooled boiling flow of refrigerant at three different pressures and varying levels of inlet liquid subcooling, are used for comparison with CFD simulations. This study integrates nucleate site density and bubble departure diameter models to enhance wall boiling model accuracy. It aims to investigate various interfacial forces and examines the S-Gamma and Adaptive Multiple Size-Group (A-MuSiG) size distribution methods for their roles in bubble break up and coalescence. These proposed approaches demonstrate their efficacy, contributing to a deeper understanding of flow boiling phenomena and the development of more accurate models. This investigation offers valuable insights into selecting the most appropriate sub-closure models for both boiling closure and momentum closure in simulating boiling flows. [ABSTRACT FROM AUTHOR]

This study introduces a Bayesian spatiotemporal modeling approach to solve inverse heat conduction problems (IHCPs), employing penalized splines within a spatiotemporal forward model. The complexity and ill-posed nature of IHCPs, characterized by potential nonexistence, nonuniqueness, or instability of solutions, pose significant challenges for traditional methods. Addressing this, our study presents a spatiotemporal forward model that incorporates spatial, temporal, and interaction terms, accurately capturing the intricate dynamics inherent in IHCPs and using this information as a leverage to solve the inverse problem. We adopted a Bayesian inference framework for the subsequent parameter estimation problem and developed a Gibbs sampling algorithm to sample from the posterior distribution of the model's parameters, enhancing the estimation process. Through case studies on a one-dimensional (1D) heat simulation and a pool boiling experiment using multisensor thermocouple data for heat flux reconstruction, we demonstrate the model's superiority over traditional methods. The inclusion of the spatiotemporal interaction term significantly enhances model performance, indicating its potential for broader application in solving IHCPs. The application of this method in both simulated and real-world scenarios highlights its effectiveness in capturing the spatiotemporal complexities of IHCPs. This work contributes to the field by offering a robust methodology for addressing the spatial and temporal complexities inherent in IHCPs, supported by a comprehensive Bayesian inference framework and the use of a Gibbs sampling algorithm for parameter estimation. [ABSTRACT FROM AUTHOR]

• Boiling coefficient increased with nozzle inlet pressure and specific enthalpy. • Boiling coefficient ranged from 300 to 4000 in the investigated trans-critical region. • Modified HNB showed an accuracy of 3 % in predicting the nozzle flow rates. • Proposed method for determining saturation pressure was superior to constant value. A modified homogeneous non-equilibrium boiling approach (HNB) was proposed for high-fidelity modelling of the trans-critical flashing process in two-phase R744 ejector nozzles. In the modified approach, the method of determining the metastable liquid saturation pressure was improved by integrating the metastable liquid enthalpy. Experimental tests were conducted on two different nozzles to calibrate the lumped accommodation coefficient in the modified HNB. The calibration dataset consisted of 30 trans-critical test points, with the motive inlet pressure ranging from 7.5 MPa to 11.5 MPa and temperature varying from 21 °C to 45 °C. It was demonstrated that the boiling coefficient was strongly related to nozzle inlet pressure and specific enthalpy. The coefficient was therefore fitted as a function of the operating condition. The modified HNB with the fitted function was then validated against another set of test data composed of 29 test points. The results demonstrated that the relative errors of the nozzle mass-flow rates were within 3 %. Finally, the modified HNB with the improved metastable liquid saturation pressure was compared and discussed with the existing HNB approach in the literature. [ABSTRACT FROM AUTHOR]

The present investigation aims to study the comparative analysis of CNT, GO, and CNT + GO nanoparticle coatings on copper surfaces under a pool boiling situation. Coating on copper surfaces is performed using the dip coating method. Pool boiling experiments are conducted for all the coated surfaces at atmospheric pressure. Water is used as a working fluid. A comparison was made based on the coated surface characteristics and pool boiling behavior of the samples. The results show that CNT + GO coating on copper surfaces is better in terms of critical heat flux (CHF) and boiling heat transfer coefficient (BHTC). It is also observed that CHF and BHTC of the CNT + GO‐coated surface are 129.19% and 194.75% higher, respectively, compared to the bare copper surface. Bubble dynamics studies were also performed for all the samples. [ABSTRACT FROM AUTHOR]

A kettle reboiler uses the latent heat from the condensation of high-temperature and high-pressure steam in the tube to produce low-pressure saturated steam in the outer shell. The deposition of particles on the tube may change the boiling heat transfer mode from nucleate boiling to natural convection, thereby deteriorating the heat transfer performance of the kettle reboiler. Therefore, it is very important to explore the deposition characteristics of particles in the kettle reboiler. In this study, the RPI boiling model based on the Euler–Euler method is used to analyze the water boiling process on the surface of the tube bundle. The DRW model and critical adhesion velocity model based on the Euler–Lagrangian method are used to calculate the motion of particles during the boiling process and the deposition (rebound) behavior. The results show that the boiling of liquid water enhances the local flow velocity of the fluid, so that the maximum flow velocity appears around the near-wall region. The local high-speed flow disperses the particles in the wake flow of the tube bundle, which inhibits the impact of particles on the wall. As the particle size increases, the wall adhesion and fluid drag on the particles are weakened, and the gravity effect gradually becomes dominant, increasing the residence time of the particles in the tube bundle and the frequency of particle impact on the wall. The particle deposition ratio first decreases and then increases. Ultimately, most particles will be deposited in the low-speed area at the end of the tube bundle. [ABSTRACT FROM AUTHOR]

The Mn(III)-based oxidation of 1,3-indanedione (1) with 1,1-diarylethenes 2a–c effectively proceeded in boiling AcOH to produce 2,2-bis(vinyl)indanediones 5a–c and 1,2'-spirobi[indene]-1',3'-diones 6a–c via the formation of 2,2-bis(2-acetoxyethyl)indanedione 3 and acetoxyindeno[1,2-b]furan-4-one 4 intermediates. On the other hand, the Mn(III)-based aerobic oxidation of 1a with 2a at room temperature resulted in bis(endoperoxide) 8a and endoperoxypropellane 9a via the production of mono(endoperoxide) 7a. The plausible reaction pathways were also discussed. [ABSTRACT FROM AUTHOR]

Ebullition transports large amounts of the potent greenhouse gas methane (CH 4 ) from aquatic sediments to the atmosphere. River beds are a main source of biogenic CH 4 , but emission estimates and the relative contribution of ebullition as a transport pathway are poorly constrained. This study meets a need for more direct measurements with a whole-year data set on CH 4 ebullition from a small stream in southern Germany. Four gas traps were installed in a cross section in a river bend, representing different bed substrates between undercut and slip-off slope. For a comparison, diffusive fluxes were estimated from concentration gradients in the sediment and from measurements of dissolved CH 4 in the surface water. The data revealed highest activity with gas fluxes above 1000 ml m - 2 d - 1 in the center of the stream, sustained ebullition during winter, and a larger contribution of ebullitive compared to diffusive CH 4 fluxes. Increased gas fluxes from the center of the river may be connected to greater exchange with the surface water, thus increased carbon and nutrient supply, and a higher sediment permeability for gas bubbles. By using stable isotope fractionation, we estimated that 12-44% of the CH 4 transported diffusively was oxidized. Predictors like temperature, air pressure drop, discharge, or precipitation could not or only poorly explain temporal variations of ebullitive CH 4 fluxes. [ABSTRACT FROM AUTHOR]

A microwave discharge inside of a methane bubble in boiling water is modeled in a 0D approximation taking into account the change in the size of the plasma bubble. The process of quenching the reaction products after the bubble detaches from the electrode surface is also simulated. The working pressure is 1 atm. It is shown that the main reaction products are H2, CO2, and CO. The ratio of CO2 and CO concentrations depends on the ratio of the initial flows of water vapor and methane. The calculated concentrations of the main decomposition products of methane and water are in good agreement with experimental data. [ABSTRACT FROM AUTHOR]

The hypervapotron structure was considered to be a feasible configuration to meet the high heat-dissipating requirement of divertors in nuclear fusion devices. In this work, symmetric CuCrZr-based transverse microchannels (TMHC) and longitudinal microchannels (LMHC) with an integrated hypervapotron channel were proposed and manufactured, and subcooled flow boiling experiments were conducted using deionized water at an inlet temperature of 20 °C with a traditional flat-type hypervapotron channel (FHC) for comparison. The LMHC and TMHC obtained lower wall temperatures than the FHC for all conditions, and the TMHC yielded the lowest temperatures. The heat transfer coefficients of the LMHC and TMHC outperformed the FHC due to the enlarged heat transfer area, and the TMHC had the greatest heat transfer coefficient (maximumly increased by 132% compared to the FHC) because the transverse-arranged microchannels were conductive, promoting the convection and liquid replenishment ability by introducing branch flow between fins; however, the microchannels of the LMHC were insensible to flow velocities due to the block effect of longitudinal microchannels. The LMHC obtained the largest pressure drop, and the pressure drop for the FHC and TMHC were comparable since the transverse-placed microchannels had little effect on frictional pressure loss. The TMHC attained the greatest comprehensive thermohydraulic performance which might bring significant insight to the structural design of hypervapotron devices. [ABSTRACT FROM AUTHOR]

As an alternative to surgical excision and magnetic resonance-guided thermal high-intensity focused ultrasound ablation of uterine leiomyoma, this work was aimed at pilot feasibility demonstration of use of ultrasound-guided boiling histotripsy for non-invasive non-thermal fractionation of human uterine leiomyoma ex vivo. A custom-made sector ultrasound transducer of 1.5-MHz operating frequency and nominal f -number F # = 0.75 was used to produce a volumetric lesion (two layers of 5 × 5 foci with a 1 mm step) in surgically resected human leiomyoma ex vivo. A sequence of 10 ms pulses (P +/ P –/ A s = 157/–25/170 MPa in situ) with 1% duty cycle was delivered N = 30 times per focus under B-mode guidance. The treatment outcome was evaluated via B-mode imaging and histologically with hematoxylin and eosin and Masson's trichrome staining. The treatment was successfully performed in less than 30 min and resulted in formation of a rectangular lesion visualized on B-mode images during the sonication as an echogenic region, which sustained for about 10 min post-treatment. Histology revealed loss of cellular structure, necrotic debris and globules of degenerated collagen in the target volume surrounded by injured smooth muscle cells. The pilot experiment described here indicates that boiling histotripsy is feasible for non-invasive mechanical disintegration of human uterine leiomyoma ex vivo under B-mode guidance, encouraging further investigation and optimization of this potential clinical application of boiling histotripsy. [ABSTRACT FROM AUTHOR]

Nucleate pool boiling is known for its exceptional heat transfer coefficients, with the use of cavities further improving bubble nucleation and heat transfer rate. To promote this heat transfer enhancement technique, a thorough understanding of the influence of cavity geometry on single bubble dynamics is required. The influence of depth and radius of cylindrical and conical cavities on the bubble dynamics of nucleate pool boiling of R1234yf were numerically investigated. The cavity radius was varied between 50 and 400 μm and the cavity depth between 100 and 1000 μm at a fixed heat flux of 28 kW/m2. It was found that the maximum equivalent diameter prior to departure was constant for cavities with radii smaller than 120 μm, while it increased linearly when increasing the cavity radius further. Cylindrical cavities exhibited high stability regardless of cavity radius or depth whereas conical cavities showed a decrease in vapor retention with increasing cavity angle. During the necking phase, the bubble interface became pinned at the cavity edge, depending on conical cavity angle, implying that smaller radii allowed for enhanced surface rewetting. Conical cavities could be considered as cylindrical cavities when the cavity angle was less than a quarter of the interface contact angle. When translating the single cavity findings to cavity array design, cylindrical cavities were recommended as they allowed for stable bubble behavior. For increased nucleation zones and rewetting, a sub-critical radius was recommended. Wider cavities were recommended for high superheat conditions as larger bubbles could enhance bubble growth. [ABSTRACT FROM AUTHOR]

Tempeh is a fermented soybean food with high nutritional value, culinary versatility, and palatability. Its popularity is rising because it aligns with the trend towards sustainable and healthy plant-based diets. However, consumers have exhibited a strong preference for local ingredients over soy. Faba bean is a promising raw material in Scandinavia due to its high protein, dietary fiber, and phytochemical content. In this study, we evaluated the effects of soaking media (vinegar, water and sodium bicarbonate with or without lactic acid bacteria (LAB)) on boiling time and physicochemical properties of faba bean-based tempeh. We demonstrated that sodium bicarbonate, with and without LAB, significantly reduces the boiling time of faba beans (7–8 min), while beans soaked in vinegar and water with and without LAB require longer boiling times for tempeh production (>16 min). Texture analysis has revealed notable variations among the samples, with statistically significant differences (p < 0.05) observed across the majority of the measured attributes. Our study has demonstrated that faba beans are suitable for tempeh production and expand the sources of possible raw materials. However, further studies are needed to investigate consumers' preferences and expectations towards faba bean-based tempeh. [ABSTRACT FROM AUTHOR]

Flow boiling with dielectric coolant is not only a highly desirable approach for effective electronic cooling but is also notorious for its poor scalability. Most current flow boiling enhancement strategies are based on silicon substrates with footprint areas less than 1 cm2, which greatly limits their applications to large-size electronics. This study developed a scalable channel configuration to facilitate efficient flow boiling on large copper substrates (∼10 cm2), in which the channel walls are formed by porous pin-fin arrays. This type of hybrid capillary wall makes up for the limitation of conventional machining in creating intricate features, making it scalable and feasible for developing large-size, two-phase cold plates. Moreover, effective two-phase separation and sustainable film evaporation have been realized in the current work. As a result, the proposed structure achieved a 512% increase in heat dissipation when the heating area scales up 480% from the silicon microchannels with micro-pin-fin arrays. Experiments showed a base heat flux of 106.1 W/cm2 was dissipated over a heating area of 9.6 cm2 using the dielectric fluid HFE-7100 at a mass flux of 247 kg/m2 s. It outperformed most existing metallic flow boiling heat sinks using the same coolant at a similarly high coefficient of performance as small-size enhanced silicon microchannels. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a hallmark of chronic liver disease which could lead to liver cirrhosis or liver cancer. However, there is currently lack of a direct treatment for liver fibrosis. Boiling histotripsy (BH) is an emerging non-invasive high-intensity focused ultrasound technique that can be employed to mechanically destruct solid tumour at the focus via acoustic cavitation without significant adverse effect on surrounding tissue. Here, we investigated whether BH can mechanically fractionate liver fibrotic tissue thereby exhibiting an anti-fibrotic effect in an animal model of liver fibrosis. BH-treated penumbra and its identical lobe showed reduced liver fibrosis, accompanied by increased hepatocyte specific marker expression, compared to the BH-untreated lobe. Furthermore, BH treatment improved serological liver function markers without notable adverse effects. The ability of BH to reduce fibrosis and promote liver regeneration in liver fibrotic tissue suggests that BH could potentially be an effective and reliable therapeutic approach against liver fibrosis. [ABSTRACT FROM AUTHOR]

VOF model and user-defined function were applied to simulate the flow boiling process of water in microchannel with V-cavities. The effects of V-cavity asymmetry (ε) and distribution on the bubble growth and detachment and the transition of gas-liquid two-phase flow in microchannel were analyzed. The results show that the magnitude of the V-cavity asymmetry can change the bubble detachment diameter and detachment time. The bubble detachment diameter of the V-cavity with asymmetry ε of 1.0 is 0.063 mm and 0.025 mm smaller than that of the V-cavity with ε of 0 and ε of 0.5, and the bubble detachment time is shortened by 5.20 ms and 2.40 ms, respectively. The transition of gas-liquid two-phase flow from bubbly flow to confined bubble flow is 2.7 mm backward along the flow direction, and the occupied area of the segment annular flow in microchannel is reduced slightly. When the V-cavity with ε of 1.0 has different distribution along the flow direction, the gas-liquid two-phase flow in microchannel presents different characteristics. The V-cavity with increasingly dense distribution can better inhibit the coalescence of bubbles in microchannel without segment annular flow, which can ensure the existence of liquid film near the wall to avoid the local drying for improving the stability and reliability of flow boiling heat transfer in microchannel. [ABSTRACT FROM AUTHOR]

This work conducts a numerical investigation of water jet impingement cooling during the steel quenching process. Although much of the simulation work in the literature relies on two-dimensional analyses, this study developed a three-dimensional CFD simulation model using Ansys-Fluent. The Eulerian mixture formulation with the volume of fluid (VOF) method was employed. It is shown that the developed model accurately simulates the boiling behavior in impingement cooling using circular water jets. The main parameters used in the simulation were: initial surface temperature of 700 °C, and jet velocity of 0.4 m / s impinging from a nozzle at 8 m m height from the heated surface. The 3D mesh has been refined in a way to maintain a y + value of 1 at the heated surface to capture the physics on the surface and to ensure that the viscous boundary layer is captured. Results such as temperature drop, boiling curve, and bubble frequency were presented and verified with the available experimental work in the literature. The developed mixture simulation using Ansys-Fluent has demonstrated its capability to numerically simulate the temperature history and boiling curves in the impingement process. This advancement will facilitate the study of numerous industrial parameters that are challenging to investigate experimentally. [ABSTRACT FROM AUTHOR]

This publication presents the first Ukrainian translation of the fourteenth chapter of the first section of the fundamental Sanskrit treatise on Ayurveda (traditional Indian medicine) Charaka Samhita. (For previous chapters, see 2017 issues of The World of the Orient and No. 2 for this year.) As it exists today, this text is thought to have arisen in the 1st century CE. The translation is of great importance for acquaintance of the Ukrainian readers with medical conceptions and life of Ancient India. The fourteenth chapter is devoted to such an Ayurvedic procedure as fomentation (svedana, from Sanskrit sveda or sweat), which means various types of therapeutic warming: warming the whole body or its individual parts; dry heat, steam heat, hot tub; warming up with or without preliminary anointing а patient's body with oil. At the beginning of the chapter, the usefulness of fomentation is justified by an analogy "Even dry poles bend by means of oleation and fomentation, then how living human beings [can not be benefited]?" The chapter insists on coordinating a power of fomentation with a season and a patient's condition. Indications and contraindications for fomentation are listed. Instructions on behavior before, during, and after a fomentation are given. A list of medicine added to the boiling water (to generate steam) is provided. [ABSTRACT FROM AUTHOR]

Entropy generation analysis is a useful method for studying the relationship between heat transfer and pressure drop in flow boiling. The flow boiling process in an actual refrigeration system is inevitably affected by oil. Therefore, the effect of oil on entropy generation needs to be investigated. A new non-azeotropic ternary refrigerant mixture, R447A, was selected as working fluid. Subsequently, flow boiling entropy generation models of R447A with and without oil were established. The effects of individual parameters on entropy generation were investigated. The entropy generation per unit tube length under different conditions was proposed as the benchmark for comparison. The results show that there is an optimal mass flux corresponding to minimum entropy generation per unit tube length at a specific oil concentration, and optimal mass flux decreases with increasing oil concentration. The tube diameter also affects the optimal mass flux of the fluid with oil, which increases with decreasing tube diameter and is smaller than that without oil for the same diameter tube. When the oil concentration is 0–4.95%, the total entropy generation exhibits a decreasing trend. Therefore, within the scope of this research, the addition of oil is beneficial for reducing the entropy generation of heat exchangers. [ABSTRACT FROM AUTHOR]

In this study, the effects of different processing ways such as roasting, soaking and boiling on heavy metal, macro and micro element contents of chickpea grains were investigated. P and K amounts of raw (control) and processed chickpea seeds were measured between 59.20 (Boiled chickpea) and 4238.69 mg/kg (control) to 600.77 (Boiled chickpea water) and 7883.69 mg/kg (Dry roasted chickpea), respectively. Fe and Mn amounts of raw (control) and processed chickpea seeds were recorded between 0.59 (Soaked chickpea water) and 58.87 mg/kg (Dry roasted chickpea) to 0.63 (Boiled chickpea water) and 27.04 mg/kg (Dry roasted chickpea), respectively. Al ve As contents of raw and processed chickpea seeds were measured between 0.75 µg/g (Boiled chickpea water) and 17.81 (control) to 3.93 (Boiled chickpea) and 9.50 µg/g (Dry roasted chickpea), respectively. In addition, Pb amounts of chickpea seeds were determined between 0.188 (Boiled chickpea) and 0.928 µg/g (Dry roasted chickpea). [ABSTRACT FROM AUTHOR]

AbstractThis paper is on 3D numerical study on nucleate boiling at high wall superheat of 13.5 K, over an oscillating base plate, using a sharp interface dual-grid level set method (SI-DGLSM)-based in-house code. These studies are performed for two nucleation sites, with two configurations of the computational domain. A micro-layer evaporation model has been used to enable 3D simulations on a coarser grid and higher wall superheats. The size of the computational domain is chosen based on the nucleation site density, reported in experiments, and the present numerical results compare well with the published experimental results; for a stationary horizontal plate under atmospheric pressure. For nucleate boiling on an oscillating plate, bubbles departing from both the nucleation sites synchronize and lock-on with the plate oscillation. Enhancement in heat transfer coefficient is observed in presence of base plate oscillations, which is attributed to increase in rate of phase change as compared to increase in rate of convective heat transfer. Non-uniform distribution of nucleation sites on the base plate leads to formation of local convergence zones on the plate, which in turn affects the motion of bubbles as they rise within the computational domain. The present work is significant as it presents 3D simulations for nucleate boiling under the effect of base plate oscillations—as a promising technique for heat transfer enhancement. [ABSTRACT FROM AUTHOR]

Both experimental and theoretical studies of fast and microscale physical phenomena occurring during the growth of vapour bubbles in nucleate pool boiling are reported. The focus is on the liquid film of micrometric thickness (a 'microlayer') that can form between the heater and the liquid–vapour interface of a bubble. The microlayer strongly affects the macroscale heat transfer and is thus important to be understood. The microlayer appears as a result of the inertial forces that cause the hemispherical bubble shape. It is shown that the microlayer can be seen as the Landau–Levich film deposited by the bubble foot edge during its receding. Paradoxically, the deposition is controlled by viscosity and surface tension. The microlayer profile measured with white-light interferometry, the temperature distribution over the heater, and the bubble shape are observed with synchronised high-speed cameras. According to the numerical simulations, the microlayer consists of two regions: a dewetting ridge near the contact line, and a longer and flatter bumped part. It is shown that the ridge cannot be measured by interferometry because of its intrinsic limitation on the interface slope. The ridge growth is linked to the contact line receding. The simulated dynamics of both the bumped part and the contact line agrees with the experiment. The physical origin of the bump in the flatter part of microlayer is explained. [ABSTRACT FROM AUTHOR]

AbstractAccurately determining the spatiotemporal distribution of boiling heat flux in a single-bubble pool is crucial for understanding the pool’s heat transfer mechanism. However, direct measurement is challenging. Utilizing an inverse heat transfer approach, where part of the temperature measurement information of the boiling wall is employed, offers an effective solution to this issue. This study explores the application of the double decentralized fuzzy inference (DDFI) method to identify the distribution of single-bubble boiling heat flux in three-dimensional heat conduction systems. Through simulation experiments, we estimate the boiling heat flux distribution of single-bubble boiling and validate the DDFI method’s effectiveness through comparative analysis. Furthermore, the measured temperature data of the single-bubble boiling process is utilized to identify the heat flux distribution on the boiling surface using the DDFI method. We reconstruct the transient temperature field of the heating wall using inversion results, and verify the reliability of the reconstruction results. [ABSTRACT FROM AUTHOR]

Pool boiling is essential in many industrial manufacturing applications. In addition, it can become critical in the journey towards improving energy generation efficiency and accomplishing the goal of net-zero carbon emissions by 2050 via new or traditional power generation applications. The effectiveness of boiling is governed by the bubble cycle. The chemistry and topographical features of the surface being heated have been found to highly impact the boiling performance, such as in the case of pool boiling enhancement when employing hydrophilic and hydrophobic surfaces via nano/micro heater surface modification. Nevertheless, it is questionable how feasible it is to create these surfaces for large-scale applications due to their manufacturing and maintenance cost and complexity. The current work assesses whether the use of nanoparticles in traditional coolants could potentially unlock the mass production of optimised heating surface modification through a metadata literature review analysis. It was discovered that self-assembled layers created as a result of the deposition of nanoparticles in coolants undergoing pool boiling seem to behave most similarly to manufactured hydrophilic surfaces. The creation of enhanced patterned-heat transfer surfaces is shown to be possible via the use of a combination of different nanoparticle suspensions in coolants. [ABSTRACT FROM AUTHOR]

BACKGROUND: Consumers of boiled cassava in Africa, Latin America and Asia use specific preference criteria to evaluate its cooking quality, in terms of texture, colour and taste. To improve adoption rates of improved cassava varieties intended for consumption after boiling, these preference criteria need to be determined, quantified and integrated as post‐harvest quality traits in the target product profile of boiled cassava, so that breeding programs may screen candidate varieties based on both agronomic traits and consumer preference traits. RESULTS: Surveys of various end‐user groups identified seven priority quality attributes of boiled cassava covering root preparation, visual aspect, taste and texture. Three populations of contrasted cassava genotypes, from good‐cooking to bad‐cooking, in three countries (Uganda, Benin, Colombia) were then characterized according to these quality attributes by sensory quantitative descriptive analysis (QDA) and by standard instrumental methods. Consumers' preferences of the texture attributes mealiness and hardness were also determined. By analysis of correlations, the consumers' preferences scores were translated into thresholds of acceptability in terms of QDA scores, then in terms of instrumental measurements (water absorption during boiling and texture analysis). The thresholds of acceptability were used to identify among the Colombian and Benin populations promising genotypes for boiled cassava quality. CONCLUSION: This work demonstrates the steps of determining priority quality attributes for boiled cassava and establishing their corresponding quantitative thresholds of acceptability. The information can then be included in boiled cassava target product profiles used by cassava breeders, for better selection and adoption rates of new varieties. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

High heat flux devices necessitate efficient heat dissipation systems, with pool boiling emerging as a promising method. Leveraging advancements in nanoscience, this study investigates the enhancement of heater surface characteristics for pool boiling through experimental means. Three bare copper surfaces are coated with a hybrid nanofluid comprising copper-based carboxylic functionalized multi-walled carbon nanotubes and distilled water at concentrations of 0.3, 0.6, and 1.0 mass% using the spin coating technique. Contact angle measurements reveal superhydrophilicity across all surfaces, ranging from 14° to 7°. The 1.0 mass% coated surface exhibits significant improvements in boiling heat transfer coefficient and critical heat flux, reaching 143 W m−2 K−1 and 2206 W m−2 K−1, respectively, representing increments of 324% and 204%. Visualization of bubble dynamics demonstrates enhanced surface roughness and active nucleation sites, leading to early bubble detachment under low heat flux conditions. Bubble sizes ranging from 0.6 to 1.6 mm indicate smaller diameters compared to bare copper surfaces, facilitating rapid heat dissipation due to more nucleation sites and proper nanofluid adhesion. The microporous surfaces prepared exhibit exceptional performance, offering potential applications in boilers, heat pipes, and various heat transfer systems. [ABSTRACT FROM AUTHOR]

This study investigates the vapor chemical composition, during the melting step of an electron beam powder bed fusion process using Ti–6Al–4V powder. A phenomenological model is proposed to analyze and discuss the vapor composition. The model focus on the heat dissipation of the molten powder. Vapor stream from the molten powder is compounded by vapor saturation pressure and rapid boiling (ebullition) of the molten pool. The model is based on post mortem results of condensed vapor (thin film), which were analyzed by X-ray photoelectron spectroscopy and glow discharge optical emission spectrometry, providing quantitative and in-depth profile data. It was found that the ratio of [Al] to [Ti] in the vapor stream is influenced by the melting conditions. As the e-beam current increases, the heat dissipation reaches the ebullition domains, and the [Al]/[Ti] ratio tends to the molar ratio of the precursor powder (Ti–6Al–4V), indicating the complete overheating of all the alloy elements. [ABSTRACT FROM AUTHOR]

Moringa oleifera is a plant native to India that is well adapted to warm climates with a high yield and low agronomic requirements. Pods are one of the edible parts of this plant and are commonly consumed in some places, (India, Morocco, etc.) when in an early vegetative state. However, both production and consumption of this plant are scarce and seasonal in Europe and treatments to extend its shelf life are required. Therefore, the aim of this study has been to evaluate the variation in the physicochemical properties of Moringa oleifera pods at two stages of maturity, tender and mature, in terms of mass variation, optical and mechanical properties, protein content, total antioxidant capacity and phenolic profile, after boiling them in tap water at 100 °C for different lengths of time (0, 2, 5, 8, 12, 16, and 20 min). The mass of the tender pods increased by 15% during cooking, while the mature pods gradually lost weight. The protein content was approximately 4% with no significant change brought about by cooking. Ferulic, trans-cinnamic, p-coumaric, and ellagic acids were found in the fresh pods. During cooking, these phenols disappeared, and others appeared, including epicatechin and quercetin 3-glucoside, especially in the tender pods. In conclusion, boiling could contribute to an improvement in the organoleptic properties of moringa pods and to an extension of their storage and to wider availability on the market. [ABSTRACT FROM AUTHOR]

In this study, pool boiling experiments were conducted using carbon nanotubes (CNTs)-Cu nanoparticle-coated porous surfaces. Applying a layer of CNTs-Cu nanoparticles on boiling surfaces resulted in the formation of porous structures, which led to a rise in the quantity of active nucleation sites. We fabricated three coated boiling test sections, namely 0.1CNTs-99.9Cu, 0.2CNTs-99.8Cu, and 0.3CNTs-99.7Cu in weight percentages. A bare copper surface and a surface coated only with Cu particles were tested as benchmarks. Distilled water was used in the pool boiling experiments. To investigate the bubble dynamics, a high-speed camera was employed, while scanning electron microscopy was utilized to analyze the morphologies of the surfaces that were coated. The objective of this research was to elucidate the impact of varying CNTs content on boiling inversion and pool boiling efficiency. Findings indicated that an increased content of CNTs improved the boiling heat transfer coefficient, with boiling inversions observed on the porous coated surfaces. [ABSTRACT FROM AUTHOR]

The aim of this article is to introduce a novel approach to identifying flow regimes and void fractions in microchannel flow boiling, which is based on binary image segmentation using digital image processing and deep learning. The proposed image processing pipeline uses adaptive thresholding, blurring, gamma correction, contour detection, and histogram comparison to separate vapor from liquid areas, while the deep learning method uses a customized version of a convolutional neural network (CNN) called U-net to extract meaningful features from video frames. Both approaches enabled the automatic detection of flow boiling conditions, such as bubbly, slug, and annular flow, as well as automatic void fraction calculation. Especially CNN demonstrated its ability to deliver fast and dependable results, presenting an appealing substitute to manual feature extraction. The U-net-based CNN was able to segment flow boiling images with a Dice score of 99.1% and classify the above flow regimes with an overall classification accuracy of 91%. In addition, the neural network was able to predict resistance sensor readings from image data and assign them to a flow state with a mean squared error (MSE) < 10−6. [ABSTRACT FROM AUTHOR]

• Heat transfer coefficient of R32 is 50 % higher than that of R410A in 1 mm chevron depth. • Heat transfer coefficient of R410A increases monotonically with mass flux, while that of R32 doesn't. • At low mass flux pressure drop of R32 exceeds that of R410A; the opposite applies at high mass flux. • Some correlations work well with R32 and R410A condensation in small gap plate heat exchangers. Compact brazed plate heat exchangers (BPHEs) with low chevron depths are widely used in new heat pumps and air-conditioners for reducing inventory and improving efficiency. This study analyses the complete condensation of R410A and R32 inside BPHEs with a chevron depth of 1 mm. The effects of the mass flux and chevron patterns (V-shaped and W-shaped) on the heat transfer coefficient (HTC) and frictional pressure drop are investigated. The HTC of R32 is 30–50 % higher than that of R410A, which has a 10–20 % higher friction factor at high mass fluxes and vice versa at low mass fluxes. The HTC of R410A monotonically increases with the mass flux, whereas that of R32 does not. The W-shaped pattern results in 30 % and 15 % higher pressure drops compared with the V-shaped pattern for R410A and R32, respectively. The friction factor of R32 decreases more sharply than that of R410A as the mass flux increases, particularly at low mass fluxes. The correlations developed by Longo et al. and Zhang et al. show the best agreement with the experimental data for the HTCs of R32 and R410A, respectively, with mean absolute percentage deviations (MAPDs) of 15 %. The friction factor correlation of Zhang et al. accurately predicts the pressure drop of R32 for the W-shaped and V-shaped patterns. In addition, it accurately predicts the pressure drop of R410A for the W-shaped pattern, with an MAPD of less than 10 %, but over-estimates it by 37 % for the V-shaped pattern. [ABSTRACT FROM AUTHOR]

Summary: In this study, the effects of germination, roasting and boiling processes on bioactive substances, mineral profiles, fatty acid composition and phenolic profiles present in soybean seeds and soybean oil extracted from soybean were investigated. While the acidity value of the crude and roasted soybean seed oils are 0.89% and 1.09%, the acidity values of the germinted and boiled soybean oils were 1.58% and 1.21%, respectively. The free fatty acid value of the germination sample group was established to be higher than the other treatment groups. The amounts of total phenolic substance were reported between 10.22 and 33.78 mgGAE/100 g. Linoleic acid amounts of soybean oil varied between 55.72% and 56.14%. The total carotenoid and flavonoid amounts of seeds were measured to be between 0.53 (control) and 2.83 μg g−1 (germination) to 43.60 mgCE kg−1 (boiled) to 126.60 mgCE kg−1 (roasting), respectively. Protein results of the seeds were established between 43.94% (control) and 46.94% (germination). The amount of K ranged from 10 883 (boiled) to 13 994 mg kg−1 (roasting), while the amount of P range from 5340.8 (control) to 5695.9 mg kg−1 germination. The amount of Ca of the samples varied between 4606.1 (control) and 5216.1 (boiled). While linoleic acid is determined at the highest rate in soybean oil obtained from crude soybean, linoleic acid amount was determined as highest in oil obtained after roasting, germination and boiling processes applied to soybean rutin contents of soybean seed samples were determined between 3.52 and 7.81 mg kg−1. Boiling and germination increased the routine value in soybean seed samples and was determined as 7.62 and 7.81 mg kg−1, respectively. Roasting, germination and boiling processes reduced the cinnamic acid values of soybeans. [ABSTRACT FROM AUTHOR]