Nucleation Properties Research Articles

Radiation and thermal embrittlement of RPV steels: the links of embrittlement mechanisms, fracture modes and microcrack nucleation and propagation properties. Part 1. Strategy, program and methods of experimental and numerical studies

Further development of local approach models is considered from viewpoint of links of local brittle fracture properties with embrittlement mechanisms and fracture modes for RPV steels. Strategy and program of experimental and numerical investigations have been developed that allows one to find how various embrittlement mechanisms and fracture modes are connected with the conditions of nucleation and propagation of microcracks resulting in brittle fracture of RPV steels. The experimental and numerical investigations are performed for 2Cr-Ni-Mo-V steel and A533 steel used for RPVs of WWER and PWR types. RPV steels are studied in the following states: (1) initial (as-produced); (2) thermally embrittled by a hardening mechanism; (3) thermally embrittled by a non-hardening mechanism; 4) irradiated. Experimental studies include testing specimens of different geometry (smooth and notched round bars, and cracked compact tension specimens), which allows us to obtain characteristics of brittle fracture under various stress triaxialities. Numerical studies performed with the probabilistic brittle fracture model Prometey aim to obtain the brittle fracture properties on micro- and macroscales for all the investigated states of the materials.Part 1 of the paper presents information concerning the investigated materials, the used procedures and methods. Part 2 gives the test results of smooth round bars of the investigated materials in various states and the stress-strain curves determined over wide temperature range. The experimental results for various specimens from the investigated steels in various states are represented and compared with the results predicted with the Prometey model in Part 3.

Radiation and thermal embrittlement of RPV steels: the links of embrittlement mechanisms, fracture modes and microcrack nucleation and propagation properties. Part 3: Brittle fracture modelling and analysis of the link of microcrack nucleation and propagation properties and embrittlement mechanisms

Radiation and thermal embrittlement of RPV steels are studied from viewpoint of links of brittle fracture properties on micro- and macroscales. Brittle fracture properties on macroscale (such as fracture toughness and fracture stress) and the critical parameters controlling nucleation and propagation of microcracks are determined on the basis of the probabilistic brittle fracture model Prometey. The experimental and numerical investigations are performed for 2Cr–Ni–Mo-V steel and A533 steel used for RPVs of WWER and PWR types. RPV steels are studied in the following states: (1) the initial (as-produced) state; (2) the thermally-embrittled state modelling hardening mechanism of embrittlement; (3) the thermally-embrittled state modelling non-hardening mechanism of embrittlement; (4) the irradiated state. The test results of various specimens (smooth and notched round bars and cracked compact tension specimens) from the investigated steels in various states are represented over brittle fracture temperature range. Brittle fracture modelling is performed with the Prometey model for all the above specimens, and the experimental and numerical results are compared. On the basis of the obtained results the links between embrittlement mechanisms, fracture modes and microcrack nucleation and propagation properties are found.

Methane hydrate formation in amino acids / sodium montmorillonite systems

To understand the occurrence of natural gas hydrates in seabed sediments, it is crucial to examine the mechanisms of methane (CH4) hydrate formation in sodium montmorillonite (Na-Mt) systems in the presence of amino acid. Accordingly, this study employed kinetics experiments and molecular dynamics simulations to investigate CH4 hydrate nucleation and growth in an Na-Mt system containing alanine (Ala), leucine (Leu), and phenylalanine (Phe), respectively. Kinetics and Raman experiments showed that, compared with Ala, Leu and Phe enhanced hydrogen bonding between water molecules surrounding Na-Mt. This enhancement was due to the long carbon chain of Leu and the phenyl ring of Phe and facilitated CH4 hydrate formation. Moreover, in the Na-Mt system, Ala reduced CH4 consumption, whereas Leu and Phe increased CH4 consumption. Molecular dynamics simulations revealed that the strength of electrostatic interactions between the negatively charged Na-Mt surface and the functional groups of amino acids affected the distribution of amino acids, thereby altering CH4 aggregation and CH4 hydrate nucleation processes. The strong interaction between Na-Mt and Ala significantly disrupted interfacial interactions between Na-Mt and water molecules. In contrast, the weaker interactions between Na-Mt and Leu and Phe, respectively, meant that these amino acids affected CH4 hydrate nucleation in the bulk-like solution by influencing the arrangement of water molecules. These findings indicate that interfacial interactions between Na-Mt and amino acids play a crucial role in CH4 hydrate formation. Overall, this study generated insights into the formation kinetics and nucleation properties of CH4 hydrates in clay mineral–amino acid complexes that may increase understanding about the occurrence of natural gas hydrates in marine sediments.

Systematic First-Principles Investigations of the Nucleation, Growth, and Surface Properties of Al11RE3 Second-Phase Particles in Al-Based Alloys

At room temperature, Al alloys have excellent mechanical properties and are widely used in automotive, electronics, aerospace and other fields, but it is difficult to maintain this advantage in the middle and high temperature ranges. To address this issue, second-phase Al11RE3 (RE represents rare earth element) was introduced into a Al-Mg-RE alloy as its primary constituent. By incorporating RE elements as additives, this material exhibits exceptional mechanical and thermal properties at elevated temperatures. Based on first principles and quasi-harmonic approximation (QHA), the nucleation growth mechanism and surface properties of second-phase Al11RE3 were studied in this paper. The interfacial energy γα/β, strain energy ΔECS and chemical driving force ΔGV of Al11RE3 were obtained. Models1, 4, and 6 have better properties of para-site connections than inter-site connections. It is found that the resistances of particle nucleation, interface energy γα/β and strain energy ΔECS, first increase and then decrease with increased atomic number REs, but they are much smaller than the chemical driving force ΔGV. A reduced chemical driving force and a diminished nucleation radius R* are more favorable for the process of nucleation. The addition of Sc is the most unfavorable for nucleation, and La has the strongest nucleating ability, which gradually decreases as the atomic number of the lanthanide element increases. The nucleation ability of the Al11RE3 phase decreases with increasing temperature, which is consistent with the experiments. The nucleation radius R* also increases with increasing temperature, indicating that the nucleation ability decreases as the atomic number of the lanthanide elements increases. Since the smaller the nucleation radius R* the easier the nucleation, compared with model4 and 6, model1 has a smaller nucleation radius R* and the smallest increment. Thus, model1 is more prominent in the nucleation mechanism. In the particle growth study, the smaller the diffusion activation energy Q, the faster the diffusion rate in the Al matrix, and hence the higher the coiling rate, which promotes the growth of second-phase particles. The diffusion activation energy Q decreases sequentially from La to Ce and then increases with atomic number. The coarsening rate KLSW of the Al11RE3 phase in models1, 4, and 6 increased with increasing temperature, which promoted the growth of particles. This paper is intended to provide a solid theoretical basis for the production and application of aluminum alloy at high temperatures.

Diverse sources and aging change the mixing state and ice nucleation properties of aerosol particles over the western Pacific and Southern Ocean

Abstract. Atmospheric particles can impact cloud formation and play a critical role in regulating cloud properties. However, particle characteristics at the single-particle level and their ability to act as ice-nucleating particles (INPs) over the marine atmosphere are poorly understood. In this study, we present micro-spectroscopic characterizations and ice nucleation properties of particles collected during a cruise from South Korea to Antarctica in 2019. Most of the samples were dominated by fresh sea salt, aged sea salt, and sea salt mixed with sulfate particles, with total number percentages ranging from 48 % to 99 % over the western Pacific and the Southern Ocean. The mixing-state index of the particle population ranged from 50 % to 95 % over the Northern Hemisphere and Southern Hemisphere. Multiphase processes on sea salt particles resulted in chlorine deficiency. This selective aging process made the marine particle population more externally mixed. Ice nucleation onset conditions primarily for the deposition mode were measured and the investigated particles showed diverse ice nucleation abilities. The fresh sea salt particles with organic coatings exhibited the highest ice nucleation ability at a relative humidity with respect to ice as low as 121 %. The sea salt mixed sulfate particle was enriched in INPs by a factor of 1.9. Aging processes affected both the mixing state of the particles and their ice nucleation abilities. Our analysis shows that assuming an internally mixed particle population in the marine atmosphere can lead to errors of several orders of magnitude in predicting ice nucleation rates.

Aerosol‐Cloud Interactions From Aviation Soot Emissions

AbstractCurrent models estimate global aviation contributes approximately 5% to the total anthropogenic climate forcing, with aerosol‐cloud interactions having the greatest effect. However, radiative forcing estimates from aviation aerosol‐cloud interactions remain undetermined. There is an expected significant increase in aircraft emissions with aviation demand expected to rise by over 4% per year. Soot may play an important role in the ice nucleation of aircraft‐induced cirrus formation due to a high emission rate, but the ice nucleating properties are poorly constrained. Understanding the microphysical processes leading to atmospheric ice crystal formation is crucial for the reliable parameterization of aerosol‐cloud interactions in climate models due to their impact on precipitation and cloud radiative properties. Ice nucleation of aircraft‐emitted soot is potentially affected by particle morphology with condensation of supercooled water occurring in pores followed by ice nucleation. However, soot has heterogeneous properties and undergoes atmospheric aging and oxidation that could change surface properties and contribute to complex ice nucleation processes. This review synthesizes current knowledge of ice nucleation catalyzed by aviation in the cirrus regime and its effects on global radiative forcing. Further research is required to determine the ice nucleation and microphysical processes of cirrus cloud formation from aviation emissions in both controlled laboratory and field investigations to inform models for more accurate climate predictions and to provide efficient mitigation strategies.

Interfacial structures and properties of sulfide-Fe matrix in steel: A first principles study

Fine sulfides can promote the refinement of microstructure and improve the strength and toughness of materials. The interface properties between sulfides and steel matrix are associated with this phenomenon. The first principles calculation combined with two-dimensional lattice mismatch and two-step nucleation theory is adopted to calculate the interface properties of TiS/bcc-Fe, TiS/fcc-Fe and TiS/MnS at the atomic level. The results show that TiS has a weak ability to promote the transition of austenite to intragranular ferrite (IGF) due to the low adhesion work value. And TiS needs to overcome energy barriers to induce the formation of IGF because the higher interface energy of TiS/bcc-Fe than TiS/fcc-Fe. The heterogeneous nucleation ability of TiS(001)/MnS(111) is stronger than that of TiS(001)/MnS(110), indicating that TiS is beneficial for improving the deformation performance of MnS without affecting the ability of MnS (110) surface to induce IGF nucleation for grain refinement. Based on the two-step nucleation theory, the structures and properties of TiS clusters are analyzed. The formation pathway of TiS/Fe interface can be described as: Tiatom + Satom + Featom → core (TiSn)–shell (fcc-Fe(111)) → core (TiS(001))–shell (fcc-Fe(110) + bcc-Fe(100)).

Influence of Chemical Modifications of the Crystallophore on Protein Nucleating Properties and Supramolecular Interactions Network.

Crystallophores are lanthanide complexes that have demonstrated outstanding induction of crystallization for various proteins. This article explores the effect of tailored modifications of the crystallophore first generation and their impact on the nucleating properties and protein crystal structures. Through high-throughput crystallization experiments and dataset analysis, we evaluated the effectiveness of these variants, in comparison to the first crystallophore generation G1. In particular, the V1 variant, featuring a propanol pendant arm, demonstrated the ability to produce new crystallization conditions for the proteins tested (hen-egg white lysozyme, proteinase K and thaumatin). Structural analysis performed in the case of hen egg-white lysozyme along with Molecular Dynamics simulations, highlights V1's unique behavior, taking advantage of the flexibility of its propanol arm to explore different protein surfaces and form versatile supramolecular interactions.

THERMOPHYSICAL PROPERTIES OF HYPOEUTECTIC, EUTECTIC AND HYPEREUTECTIC Al-Si AUTOMOTIVE ALLOYS UNDER AGEING TREATMENT

Influence of different levels of silicon under a variety of thermal treatment is investigated on the thermophysical behaviour of Al-Si-Cu-Mg automotive alloys. Conventional cast alloys are subjected to T6 heat treatment for age hardening. Hardness values, thermal conductivity along with microstructural observation under different heat-treated conditions are well thought-out to comprehend the ageing performance and the precipitation behaviour of the alloys. From these investigational results it is indicated that two successive hardening peaks take place in the agedalloys. Ageing sequence consists of different phases like a supersaturated solid solution, GP zones, intermediate βʹʹ, intermetallic βʹ, equilibrium β and the Q phase but GP zones and the metastable phases are most likely responsible for these ageing peaks. Thermal conductivity decreases for these precipitates formation during ageing and increases for relieving the internal stress, dissolution of metastable phase and coarsening the precipitation of the alloys. Addingup of Si to the alloy showed earlier ageing peaks with higher intensities intended for its increasing properties of heterogeneous nucleation and diffusion kinetics. After ageing around at 200°C for four hours the alloys offer the height hardness. Microstructural study reveals that eutectic silicon makes the grain boundary coarsen and beyond the eutectic composition the star-shaped blocky primary Si is formed. Subsequent to ageing at 350oC for one hour the alloys reach completely recrystallized state.

Soot aerosols from commercial aviation engines are poor ice-nucleating particles at cirrus cloud temperatures

Abstract. Ice-nucleating particles catalyze ice formation in clouds, affecting climate through radiative forcing from aerosol–cloud interactions. Aviation directly emits particles into the upper troposphere where ice formation conditions are favorable. Previous studies have used proxies of aviation soot to estimate their ice nucleation activity; however, investigations with commercial aircraft soot from modern in-use aircraft engines have not been quantified. In this work, we sample aviation soot particles at ground level from different commercial aircraft engines to test their ice nucleation ability at temperatures ≤228 K as a function of engine thrust and soot particle size. Additionally, soot particles were catalytically stripped to reveal the impact of mixing state on their ice nucleation ability. Particle physical and chemical properties were further characterized and related to the ice nucleation properties. The results show that aviation soot nucleates ice at or above relative humidity conditions required for homogeneous freezing of solution droplets (RHhom). We attribute this to a mesopore paucity inhibiting pore condensation and the sulfur content which suppresses freezing. Only large soot aggregates (400 nm) emitted under 30 %–100 % thrust conditions for a subset of engines (2 out of 10) nucleate ice via pore condensation and freezing. For those specific engines, the presence of hydrophilic chemical groups facilitates the nucleation. Aviation soot emitted at thrust ≥ 100 % (sea level thrust) nucleates ice at or above RHhom. Overall, our results suggest that aviation soot will not contribute to natural cirrus formation and can be used in models to update impacts of soot–cirrus clouds.

On the Role of Starchy Grains in Ice Nucleation Processes.

Little is known about the role of starchy food on climate change processes like ice nucleation. Here, we investigate the ice nucleation efficiency (INE) of eight different starchy food materials, namely, corn (CO), potato (PO), barley (BA), brown rice (BR), white rice (WR), oats (OA), wheat (WH), and sweet potato (SP), in immersion freezing mode under mixed-phase cloud conditions. Notably, among all these food materials, PO and BA exhibit the highest ice nucleation efficiency with ice nucleation temperatures as high as -4.3 °C (T50 ∼ -7.0 ± 0.5 °C) and -6.5 °C (T50 ∼ -7.2 ± 0.2 °C), respectively. We also explore the effect of environmentally relevant physicochemical conditions on ice nucleation efficiency, including different pH, temperature, UV/O3/NOx exposure, and various cocontaminants. The change in shape, size, surface properties, hydrophobicity, and crystallinity of materials accounted for the altered INE. The increase in shape, size, and hydrophobicity of the sample generally reduces the INE, whereas an increase in crystallinity enhances the INE of the sample under our experimental conditions. The results suggest that environmentally relevant concentrations slightly alter INE, indicating their role as catalysts in environmental matrices. The outcome of studies on the ice nucleation properties of these food-containing aerosols might help in the physicochemical understanding of other biomolecule-induced ice nucleation, which is still an underdeveloped research area.

Clothing Textiles as Carriers of Biological Ice Nucleation Active Particles.

Microplastics have littered the globe, with synthetic fibers being the largest source of atmospheric microplastics. Many atmospheric particles can act as ice nucleators, thereby affecting the microphysical and radiative properties of clouds and, hence, the radiative balance of the Earth. The present study focused on the ice-nucleating ability of fibers from clothing textiles (CTs), which are commonly shed from the normal wear of apparel items. Results from immersion ice nucleation experiments showed that CTs were effective ice nucleators active from -6 to -12 °C, similar to common biological ice nucleators. However, subsequent lysozyme and hydrogen peroxide digestion stripped the ice nucleation properties of CTs, indicating that ice nucleation was biological in origin. Microscopy confirmed the presence of biofilms (i.e., microbial cells attached to a surface and enclosed in an extracellular polysaccharide matrix) on CTs. If present in sufficient quantities in the atmosphere, biological particles (biofilms) attached to fibrous materials could contribute significantly to atmospheric ice nucleation.

Manipulation of Crystallization Nucleation and Mechanical Properties of PBAT Films by Octadecylamine-Cellulose

Manipulation of Crystallization Nucleation and Mechanical Properties of PBAT Films by Octadecylamine-Cellulose

Impact of high-power impulse magnetron sputtering pulse width on the nucleation, crystallization, microstructure, and ferroelectric properties of hafnium oxide thin films

The impact of the high-power impulse magnetron sputtering (HiPIMS) pulse width on the crystallization, microstructure, and ferroelectric properties of undoped HfO2 films is investigated. HfO2 films were sputtered from a hafnium metal target in an Ar/O2 atmosphere, varying the instantaneous power density by changing the HiPIMS pulse width with fixed time-averaged power and pulse frequency. The pulse width is shown to affect the ion-to-neutral ratio in the depositing species with the shortest pulse durations leading to the highest ion fraction. In situ x-ray diffraction measurements during crystallization demonstrate that the HiPIMS pulse width impacts nucleation and phase formation, with an intermediate pulse width of 110 μs stabilizing the ferroelectric phase over the widest temperature range. Although the pulse width impacts the grain size with the lowest pulse width resulting in the largest grain size, the grain size does not strongly correlate with the phase content or ferroelectric behavior in these films. These results suggest that precise control over the energetics of the depositing species may be beneficial for forming the ferroelectric phase in this material.

Navigating the challenges of lipid nanoparticle formulation: the role of unpegylated lipid surfactants in enhancing drug loading and stability.

Lipid nanoparticles have proved an attractive approach for drug delivery; however, the challenges of optimising formulation stability and increasing drug loading have limited progression. In this work, we investigate the role of unpegylated lipid surfactants (helper lipids) in nanoparticle formation and the effect of blending helper lipids with pegylated lipid surfactants on the formation and stability of lipid-based nanoparticles by nanoprecipitation. Furthermore, blends of unpegylated/pegylated lipid surfactants were examined for ability to accommodate higher drug loading formulations by means of a higher weight percentage (wt%) of drug relative to total mass of formulation components (i.e. drug, surfactants and lipids). Characterisation included evaluation of particle diameter, size distribution, drug loading and nanoformulation stability. Our findings demonstrate that the addition of unpegylated lipid surfactant (Lipoid S100) to pegylated lipid surfactant (Brij S20) enhances stability, particularly at higher weight percentages of the core material. This blending approach enables drug loading capacities exceeding 10% in the lipid nanoparticles. Notably, Lipoid S100 exhibited nucleating properties that aided in the formation and stabilisation of the nanoparticles. Furthermore, we examined the incorporation of a model drug into the lipid nanoparticle formulations. Blending the model drug with the core material disrupted the crystallinity of the core, offering additional potential benefits in terms of drug release and stability. This comprehensive investigation provides valuable insights into the interplay between surfactant properties, core material composition, and nanoparticle behaviour. The study enhances our understanding of lipid materials and offers guidance for the design and optimisation of lipid nanoparticle formulations.

Anthropogenic Dust as a Significant Source of Ice‐Nucleating Particles in the Urban Environment

AbstractAnthropogenic dust is an important constituent of airborne particles in the urban environment but its ice nucleation activity remains poorly investigated. Here, we studied the sources and ice nucleating properties of size‐resolved particles in the urban atmosphere under mixed‐phase cloud conditions. The heat‐resistant ice nucleating particles (INPs) unexpectedly contributed ∼70% of the supermicron INPs at temperatures below −15°C. A detailed chemical composition analysis of size‐resolved particles revealed that these INPs were associated with anthropogenic dust, such as traffic‐influenced road dust. A parameterization based on supermicron particles was developed to predict the anthropogenic dust INP concentration, given their correlations on concentration and similarity in chemical compositions. Once integrated into global models, this parameterization holds the potential to assess the contribution of anthropogenic dust to INPs on a global scale. Given the considerable presence of anthropogenic dust in the atmosphere and its significant role as INPs, we suggest it may be an important aerosol source influencing cloud microphysics and warrant further investigations.

Effect of Acidity on Ice Nucleation by Inorganic-Organic Mixed Droplets.

Aerosol acidity significantly influences heterogeneous chemical reactions and human health. Additionally, acidity may play a role in cloud formation by modifying the ice nucleation properties of inorganic and organic aerosols. In this work, we combined our well-established ice nucleation technique with Raman microspectroscopy to study ice nucleation in representative inorganic and organic aerosols across a range of pH conditions (pH -0.1 to 5.5). Homogeneous nucleation was observed in systems containing ammonium sulfate, sulfuric acid, and sucrose. In contrast, droplets containing ammonium sulfate mixed with diethyl sebacate, poly(ethylene glycol) 400, and 1,2,6-hexanetriol were found to undergo liquid-liquid phase separation, exhibiting core-shell morphologies with observed initiation of heterogeneous freezing in the cores. Our experimental findings demonstrate that an increased acidity reduces the ice nucleation ability of droplets. Changes in the ratio of bisulfate to sulfate coincided with shifts in ice nucleation temperatures, suggesting that the presence of bisulfate may decrease the ice nucleation efficiency. We also report on how the morphology and viscosity impact ice nucleation properties. This study aims to enhance our fundamental understanding of acidity's effect on ice nucleation ability, providing context for the role of acidity in atmospheric ice cloud formation.

Thermal and Mechanical Properties of Biocomposites Based on Polylactide and Tall Wheatgrass.

Biocomposites based on polylactic acid (PLA), tall wheatgrass (TWG), and hemp (H) were made by injection molding. The article discusses the impact of the agrofiller content on the composite properties, including thermal (DSC, DMA, and TG) and mechanical characteristics (tensile modulus, tensile strength, and impact strength). Generally, the introduction of a plant filler into the polylactide matrix reduced the thermal resistance of the resulting composites. Plant fillers influenced primarily the cold crystallization process, probably due to their nucleating properties. The addition of fillers to the PLA matrix resulted in an increased storage modulus across all tested temperatures compared to pure PLA. In the case of a composite with 50% of plant fillers, it was almost 118%. The mechanical properties of the tested composites depended significantly on the amount of plant filler used. It was observed that adding 50% of plant filler to PLA led to a twofold increase in tensile modulus and a decrease in tensile strength and impact strength by an average of 23 and 70%, respectively. It was determined that composites incorporating tall wheatgrass (TWG) particles exhibited a slightly elevated tensile modulus while showcasing a marginally reduced strength and impact resistance in comparison to composites containing hemp (H) components.

Change in the structure and mechanical properties of Al–Mg–Si alloys caused by the addition of other elements: A comprehensive review

Understanding 6xxx AA (Al–Mg–Si alloys) relies heavily on structural analysis at the atomic level. Because the nanoscale precipitates that form during artificial ageing essentially strengthen the alloys, it is crucial to lessen the negative effects of Natural Ageing (NA) and enhance the age hardening of Al–Mg–Si alloys. Numerous studies have shown that when different elements are added to 6xxx AA, NA is suppressed. This work includes a thorough and numerical description of the various elements that are added to 6xxx AA. This article gives information on the additional elements Li, Cu, Zn, and Ag that will form new phases and occupy a preferred site in 6xxx AA at different weight percentages. However, between metastable phases, 6xxx AA exhibit different element segregation, which improved the mechanical properties like hardness reported in this review work. Additionally, research on the addition of various other elements, such as Ni, Co, Au, and Cd to 6xxx AA is reported in this review paper to summarise the influence of these elements on the evolution of microstructural features and their correlation with mechanical properties. This area has received very little research and may be used in the future to enhance the mechanical properties of 6xxx AA. By encouraging precipitate nucleation, morphology, and mechanical properties through the addition of foreign elements, the results of this review paper reveal a novel pathway for precipitation hardening.

Experimental investigation on the evolution of bubble behavior in subcooled flow boiling in narrow rectangular channel based on bubble tracking algorithm

The nucleate subcooled boiling is an efficient heat transfer form and plays an important role in many cooling applications. The size and distribution of bubbles in subcooled boiling have considerable influence on boiling heat transfer. In this paper, subcooled flow boiling experiment is carried out to investigate the nucleation point density and detachment frequency of bubbles under different system pressure, and the test section is full transparent. Since the whole body of the test section is composed of transparent materials, it can be observed from different directions to obtain high quality images. A bubble tracking algorithm has been developed, which can effectively determine the diameter and position of detached bubbles, thereby inferring the nucleation point density and detachment frequency of bubbles. Besides, the distinctive properties of bubble nucleation within narrow rectangular channel are verified by comparing bubble detachment diameters with existed models. Finally, models for bubble nucleation point and detachment frequency under different operating conditions were proposed and verified through experimental results.