Shell Thickness Research Articles

Effect of dietary supplementation of wild leek (Allium tricoccum) and garlic (Allium sativum) leaves on production, egg quality, serum lipid profile, intestinal morphology and nutrient digestibility of laying quails.

In this study, the effects of adding dried wild leek and garlic leaves to the diet of laying quails on egg quality, production performance, intestinal histomorphology, nutrient digestibility, and serum biochemical traits were evaluated. 168- 30 weeks aged- laying quails were randomly arranged into 7 treatments (control group and three different levels (0.5%, 1%, and 1.5%) of wild leek or garlic leaves), 6 replicates, and 4 quails per pen. According to the study, the highest hen-day production was achieved by adding 0.5% garlic leaves, and the egg weight was higher with 1% garlic leaves and 0.5% wild leek compared to the control group (P < 0.05). In addition, adding garlic leaves decreased the average daily feed intake and increased high-density lipoprotein concentration. However, adding both herbs did not influence yolk height, albumin height, shell thickness, and Haugh unit (P > 0.05). All supplemented treatments significantly increased the formerly Roche Yolk Color Fan (DSM) index compared to the control. Quails fed with 1% garlic leaves declined serum cholesterol, very low-density lipoprotein, low-density lipoprotein, and uric acid. Moreover, three levels of garlic leaves decreased triglyceride concentration. Adding 0.5% and 1% garlic leaves to the diet could increase the jejunal, and ileal villus height-to-crypt depth ratio. Furthermore, 1% and 1.5% garlic leaves supplementation elevated organic matter, ash, and crude protein digestibility. In conclusion, supplementing 1% garlic leaves to the quail's diet could improve egg weight, intestinal morphology, and nutrient digestibility, improving lipid profiles and reducing uric acid concentration in the serum. However, both plants were rich pigment sources, increasing the DSM index.

Colossal Core/Shell CdSe/CdS Quantum Dot Emitters.

Single-photon sources are essential for advancing quantum technologies with scalable integration being a crucial requirement. To date, deterministic positioning of single-photon sources in large-scale photonic structures remains a challenge. In this context, colloidal quantum dots (QDs), particularly core/shell configurations, are attractive due to their solution processability. However, traditional QDs are typically small, about 3 to 6 nm, which restricts their deterministic placement and utility in large-scale photonic devices, particularly within optical cavities. The largest existing core/shell QDs are a family of giant CdSe/CdS QDs, with total diameters ranging from about 20 to 50 nm. Pushing beyond this size limit, we introduce a synthesis strategy for colossal CdSe/CdS QDs, with sizes ranging from 30 to 100 nm, using a stepwise high-temperature continuous injection method. Electron microscopy reveals a consistent hexagonal diamond morphology composed of 12 semipolar {101̅1} facets and one polar (0001) facet. We also identify conditions where shell growth is disrupted, leading to defects, islands, and mechanical instability, which suggest synthetic requirements for growing crystalline particles beyond 100 nm. The stepwise growth of thick CdS shells on CdSe cores enables the synthesis of emissive QDs with long photoluminescence lifetimes of a few microseconds and suppressed blinking at room temperature. Notably, QDs with 80 and 100 CdS monolayers exhibit high single-photon emission purity with second-order photon correlation g(2)(0) values below 0.2.

MORPHOTYPE MATTERS: AN EXPERIMENTAL ANALYSIS OF THE MORPHOLOGICAL FIDELITY OF GASTROPOD STEINKERNS

Abstract Gastropods are commonly preserved as steinkerns (internal casts), a mode of fossilization that leads to loss of external morphological features. This loss of information is problematic for taxonomic identification and ecological inference in evaluating assemblages where original shell material is not preserved. We seek to quantify how closely gastropod steinkerns represent the morphology of their original shells. We investigated this relationship experimentally by fabricating steinkerns in silicone from modern gastropod shells and comparing their geometry to that of the shells we used to create them. In addition to recording traces of ornamentation such as ribs and spines, we used a theoretical morphospace framework to evaluate the fidelity of shell-coiling parameters in steinkerns. Our results show that some morphotypes reflect their taxonomic identification more accurately than others, indicating that steinkern fidelity is highly variable. Experimental steinkerns consistently cluster less reliably by morphotype than their original shell counterparts. Additionally, we find that shell thickness is an important factor in determining steinkern fidelity. The fidelity of the high-spired Duplicaria duplicata, for example, is significantly lower than the average value for the morphotypes investigated whereas the fidelity of planispiral Haplotrema concavum and open-coiling Epitonium is significantly higher, a trend related to shell thickness. Thus, taxonomic identification and subsequent analyses, such as community composition, of steinkern assemblages must recognize this differential fidelity to counter preservational biases.

Experimental and numerical investigation on axial compression behaviour of prefabricated ECC shell–reinforced concrete column

To improve the mechanical behaviour of traditional reinforcement concrete (RC) column, a novel prefabricated engineered cementitious composite (ECC)–reinforced concrete composite (ECC shell–C) column was proposed in this study. Subsequently, five prefabricated ECC shell–C columns, as well as one cast–in–place (CIP) RC column and one CIP pure ECC column, were designed and manufactured. Then, axial compression tests were carried out to explore their mechanical behaviour with considering the effect of the ECC shell thickness t and stirrup ratio ρv. On this basis, a numerical analysis method for the composite column was developed and verified. And numerical parametric study was carried out to clarify the influence of the design parameters on the axial compression behaviour of the prefabricated ECC shell–RC columns, including the compressive strength of ECC (fc,ecc) and concrete (fc), as well as the longitudinal reinforcement ratio (ρs). The experimental and numerical results demonstrated that the ECC shell can improve cracking resistance, ductility capacity and energy dissipation capacity of the RC column. The accumulated energy dissipation and ductility coefficient of the prefabricated ECC shell–RC columns with different t was 2.13–2.46 times and 1.14–1.35 times greater than those of the RC column, respectively. The ρv had small influence on the bearing capacity of the prefabricated ECC shell–RC columns, which can be appropriately reduced in practical application. The numerical analysis method considering the confinement effect of ECC shell can provide reliable prediction for the axial compression behaviour of prefabricated ECC shell–RC columns. fc,ecc and fc have the positive influence on the bearing capacity of the prefabricated ECC shell–RC columns but have negative influence on the ductility; meanwhile a moderately lower ρs will not significantly reduce the ductility.

Role of Nannochloropsis Oculata supplement in improving performance, antioxidant status, blood metabolites, and egg quality of laying hens under hot environmental conditions

The increase in environmental temperature led to economic losses in the poultry industry, urging the use of feed supplements to mitigate the negative effects on chick's welfare and performance. Therefore, this study aimed to examine the effects of marine microalgae (Nannochloropsis Oculata, N. Oculata) additive on commercial Brown Lohmann laying hen's performance, blood metabolites, and antioxidant status under hot environmental conditions. One hundred and eighty birds (34 weeks old with an initial body weight of 1885 ± 23.5 g) were used till 47 weeks. The birds were divided into three equal groups (birds in each group were distributed into four equal replicates 15 hens/ replicate). The 1st group was the control (CON) and was fed the basal diet, while the 2nd (TR1) and 3rd (TR2) groups were fed the basal diet supplemented with 0.5 and 1.0% of N. Oculata, respectively. The results showed that total protein and globulin concentrations increased (P < 0.05) in treated groups compared with the control group, whereas, albumin concentration increased (P < 0.05) in TR2 compared to the control group. The concentration of ALT and AST decreased in hens fed N. Oculata. Supplementing with N. Oculata reduced serum cholesterol and creatinine concentrations, while glucose concentration increased (P < 0.05) in the treated groups compared to the control group. Serum calcium, total antioxidant capacity (TAC), Triiodothyronine (T3), and progesterone increased (P < 0.05) in hens fed N. Oculata. N. Oculata supplement improved production performance through a positive effect on egg number, egg weight, egg mass, feed conversion ratio, and mortality rate. In addition, the overall mean of shell thickness increased (P < 0.05) in hens fed N. Oculata. It can be concluded that the supplementation of 1.0% N. Oculata to the laying hens' diet enhanced productive performance, serum constituents, and antioxidant status under hot environmental conditions.

Simultaneous improvements in energy density and thermal conductivity of PAN polymer nanocomposites enabled by core-shell structure BZCT@BNNS nanofibers

If the heat generated by electronic devices in high-power applications cannot be dissipated in a timely manner, it will not only affect the use of the equipment but also reduce its service life. Therefore, there is an urgent need to develop thin films of dielectric nanocomposites with high thermal conductivity, high energy storage, and excellent flexibility and electrical insulation performance. In this study, we reported the successful preparation of BZCT nanofibers (BZCT NFs) and core-shell structures BZCT@BNNS nanofibers using electrospinning and coaxial electrospinning techniques, respectively, and there were used to composite with polyacrylonitrile (PAN) polymer matrix to prepare BZCT NFs/PAN and BZCT@BNNS/PAN dielectric nanocomposites thin film. Research has found that when the shell thickness of BNNS is 15 nm and BZCT@BNNS (15 nm) volume fraction is 20 vol%, the comprehensive performance of the dielectric nanocomposites is the best, with thermal conductivity and energy storage performance of 3.36 W m−1K−1 and 12.23 J/cm3, respectively. Therefore, the nanocomposites thin film can be used as a potential high-performance dielectric material for thermal management applications in high-power density electronic devices.

Rational synthesis of core/shell heterostructured quantum dots for improved self-powered photodetection performance enabled by energy band engineering

Colloidal quantum dots (CQDs), especially core-shell QDs, have attracted dramatic interests as emerging materials in optoelectronic devices due to their size tuneable band-gap, high absorption coefficient, facile and low-cost synthesis routing, etc. However, the precise design of core/shell band engineering along with charge carrier transfer efficiency are still challenging, inevitably impacting the performance of optoelectronic devices. Herein, three different types of CdSe/CdS core-shell heterostructured QDs have been obtained via a proposed synthesis strategy of adjusting the core size but fixing the shell thickness. The performance of the core-shell QDs based self-powered photodetectors can be efficiently regulated by the optimization of synthesis strategy with the design of energy band alignment. Compared to the quasi type-II and the type-I QDs devices, the Ilight/Idark ratio of type-II heterostructure based photodetector is increased by ∼2 and ∼5 orders of magnitude, respectively. The champion device exhibits extraordinary optoelectronic performance in terms of ultrahigh light-to-dark current ratio of 105, photoresponsivity of 10.64 mA/W, at bias of 0 V, respectively. The charge carrier dynamics and transfer mechanisms of the QDs were further investigated, revealing the improved carrier separation and transportation efficiency induced by a strong build-in electric field in type-II CdSe/CdS core-shell heterostructure. This work provides a new strategy for the next-generation self-powered QDs optoelectronics enabled by the proposed synthesis approach along with the design of energy band alignment.

Assembly of Gold Nanostar Cores Within Silica Shells and Its Impact on Solid-State SERS and Nonenzymatic Catalytic Sensing.

Metal core and dielectric shell nanoparticles (NPs) have garnered considerable attention for their multifaceted properties and extensive applications across diverse fields of nanoscience and nanotechnology. However, a literature gap exists regarding the impact of assembled metallic nanostar cores within a single shell, particularly concerning surface-enhanced Raman scattering (SERS) and electrochemical sensing. In this study, we have demonstrated the better performance of assemblies of gold nanostars (AuNSs) enclosed in single silica shell for SERS enhancement and electrocatalytic activity, particularly in the fields of ascorbic acid (AA) and glucose sensing. We have devised a method to isolate and passivate nanostar assemblies, ranging from 2 to 30 nanostars per assembly, with a functionalized silica (SiO2) shell, facilitating their preservation. The engineered thickness of the silica shell ensures unhindered optical measurements while elucidating the influence of multiple AuNS cores. Due to the formation of nanogaps and nanojunctions between AuNSs within assembly, we have achieved a maximum SERS enhancement factor (EF) of 1.416 × 1010 for the rhodamine 6G analyte. Utilizing assembled AuNS cores within a single silica shell, we have demonstrated AA (sensitivity of 5.278 × 10-5 μA μM-1 cm-2) and glucose (sensitivity of 7.519 × 10-4 μA μM-1 cm-2) sensing via a nonenzymatic electrochemical pathway.

The Melting Behavior of Hydrogen Direct Reduced Iron in Molten Steel and Slag: An Integrated Computational and Experimental Study

Direct reduced iron (DRI) and hot briquetted iron (HBI) are essential feedstocks for tramp element control in the electric arc furnace (EAF). Due to greenhouse gas (GHG) concerns related to CO2 emissions, hydrogen as a substitute for natural gas and a reductant in DRI production is being widely explored to reduce GHG emissions in ironmaking. This study examines the melting behavior of hydrogen DRI (H-DRI) pellets in the EAF containing low-carbon (0.1 wt.%) molten steel and molten slag. A computational heat transfer model was developed to predict the melting behavior of H-DRI pellets. To validate the model, a set of experimental laboratory simulations was conducted by immersing H-DRI in a molten steel bath and slag. The temperature history at the center of the pellet during melting and the shell thickness at different melting stages were utilized to validate the model. The simulation results agree with the experimental measurements of steel balls and H-DRI in different metallic molten steel and slag baths.

Dynamic Analysis of 2D FG Porous Thick Cylindrical Shells Under Thermal Shock

In this research, a thick hollow cylindrical shell made of bidirectional functionally graded open cell porous materials under internal thermal shock according to the classical theory of linear thermo-elasticity is examined for the first time. The cylinder is made of a porous cellular material and its porosity varies along both radial and axial directions continuously. The governing motion equations are obtained by using 2D-axisymmetric theory of linear thermo-elasticity rather than shell theories. This theory represents thickness stretching and gives more precise results. Graded finite element method is employed to model the problem. Applying this method rather than conventional FEM leads to more accurate results, especially for dynamic analyses. The cubic higher order element is used for dividing the solution domain. To obtain transient temperatures, Crank–Nicolson algorithm is used and then the Newmark procedure is used to derive time responses of displacement and stress components. The time history of displacements and stress components for different radial and axial power law exponents, porosity coefficient, boundary conditions, length-to-thickness ratio and two different porosity patterns are investigated in detail. The obtained results show that thermal-induced vibration is generally caused by hoop stress, and frequency and amplitude of vibrations and velocity of stress waves are considerably influenced by the porosity distribution, porosity coefficient and power law exponents in both directions.

Unity quantum yield of InP/ZnSe/ZnS quantum dots enabled by Zn halide-derived hybrid shelling approach

Environment-benign indium phosphide (InP) quantum dots (QDs) show great promise as visible emitters for next-generation display applications, where bright and narrow emissivity of QDs should be required toward high-efficiency, high-color reproducibility. The photoluminescence (PL) performance of InP QDs has been consistently, markedly improved, particularly owing to the exquisite synthetic control over core size homogeneity and core/shell heterostructural variation. To date, synthesis of most high-quality InP QDs has been implemented by using zinc (Zn) carboxylate as a shell precursor that unavoidably entails the formation of surface oxide on InP core. Herein, we demonstrate synthesis of superbly bright, color-pure green InP/ZnSe/ZnS QDs by exploring an innovative hybrid Zn shelling approach, where Zn halide (ZnX2, X = Cl, Br, I) and Zn oleate are co-used as shell precursors. In the hybrid Zn shelling process, the type of ZnX2 is found to affect the growth outcomes of ZnSe inner shell and consequent optical properties of the resulting heterostructured InP QDs. Enabled by not only the near-complete removal of the oxide layer on InP core surface through the hybrid Zn shelling process but the controlled growth rate of ZnSe inner shell, green InP/ZnSe/ZnS QDs achieve a record quantum yield (QY) up to unity along with a highly sharp linewidth of 32 nm upon growth of an optimal ZnSe shell thickness. This work affords an effective means to synthesize high-quality heterostructured InP QDs with superb emissive properties.

Wind buckling analysis of cylindrical shells with various geometric imperfections

This study addresses the complexity of buckling behavior in cylindrical shells subjected to non-uniform wind loading, emphasizing the significant impact of geometric parameters on buckling patterns. Cylinders with varying aspect ratios exhibit distinct linear and nonlinear buckling behaviors, complicating the determination of the most detrimental structural imperfections across different geometries. Notably, imperfections affecting stocky cylinders may be less impactful for slender ones. This paper introduced equations for calculating linear critical pressures under wind loading, followed by an extensive numerical analysis assessing the imperfection sensitivity in anchored cylindrical shells of uniform thickness with diverse aspect ratios. Two types of geometric imperfections were employed to assess their influence on the nonlinear buckling strength of cylinders with varying geometries. Results demonstrate that eigenmode imperfections predominantly compromise the buckling strength of stocky cylinders, whereas nonlinear incremental mode imperfections significantly influence the nonlinear critical pressures of intermediate-length and slender cylinders. Consequently, empirical expressions have been formulated to calculate the imperfection reduction factor, offering a precise evaluation of nonlinear buckling pressures in imperfect cylinders under wind loading.

A closer look at the effects of oxygen on the photoluminescence properties of CdSe/CdS quantum dots.

We present a detailed study on the effects of oxygen on the photoluminescence properties of CdSe/CdS quantum dots (QDs). We investigated the role of oxygen by performing confocal measurements on thin films as well as on single particles while rapidly exchanging the gaseous environment between oxygen and an inert gas atmosphere. We found that the deionization of negatively charged particles by oxygen depends on both the excitation power and the shell thickness of the QDs. For QDs with thin shells, which exhibit strong photoluminescence blinking, we observed that the presence of oxygen affects both band-edge carrier blinking and hot-carrier blinking.

Effects of β-Mannanase Supplementation and Soyhull Inclusion on Production Performance, Economics, Egg Quality, Blood Biochemicals, Nutrient Digestibility, and Intestinal Morphology in Golden Brown Hens (RIR × Fayoumi) during Late Peak Production.

This study investigated the effects of the β-mannanase enzyme and soyhulls on production performance, economics, egg quality, hematology and serum biochemistry, nutrient digestibility, gut morphology, digesta viscosity, and excreta consistency in laying hens during the late peak production phase (37 to 40 weeks of age). Golden brown hens (RIR × Fayoumi; n = 200) were fed a control diet (no soyhulls or enzymes) and diets containing four combinations, i.e., 3% soyhulls with 20 mg/kg β-mannanase (D1), 3% soyhulls with 30 mg/kg β-mannanase (D2), 9% soyhulls with 20 mg/kg β-mannanase (D3), and 9% soyhulls with 30 mg/kg β-mannanase (D4), for four weeks in four replicates of 10 birds each. Overall, a significantly higher (p < 0.05) feed intake, weight gain, feed conversion ratio, and water intake were calculated in the D2 group as compared to the control and remaining combinations of soyhulls and β-mannanase. No mortality was recorded during the entire experiment. Economically, the D1 and D2 groups showed the best results as compared to the D3 and D4 groups. Egg quality parameters like egg weight, shell weight and shell thickness, yolk weight, albumen weight and height, and the Haugh unit remained unchanged (p > 0.05). Similarly, the D2 group showed significantly lower total cholesterol, LDL, and VLDL levels and enhanced gut morphology with greater villus width, height, crypt depth, and surface area across intestinal segments. Crude protein (CP), crude fiber (CF), crude fat, and ash digestibility were higher (p < 0.05) in the D1 and D2 groups compared to the control. Digesta viscosity, excreta consistency, and other egg quality parameters remained unaffected. In conclusion, the dietary inclusion of a combination of 3% soyhulls and 30 mg/kg β-mannanase may have potential benefits for laying hens by improving some production performance and egg quality indicators and economics, lowering blood cholesterol, LDL, and VLDL levels, enhancing nutrient digestibility, and improving gut morphology without affecting egg quality.

Tailoring Quantum Dot Shell Thickness and Polyethylenimine Interlayers for Optimization of Inverted Quantum Dot Light-Emitting Diodes

Tailoring Quantum Dot Shell Thickness and Polyethylenimine Interlayers for Optimization of Inverted Quantum Dot Light-Emitting Diodes

Topology optimization of curved thick shells using level set method and non-conforming multi-patch isogeometric analysis

We present a novel framework for topological shape optimization of curved non-conforming multi-patch and trimmed thick-shells subjected to external loads. Our method integrates the level set method (LSM) with a diffuse interface, a Hadamard shape derivative, and multi-patch isogeometric analysis (IGA) into a gradient descent algorithm to systematically capture the evolution of the shape. This integration enables us to directly manipulate CAD-compatible geometries and analysis techniques and to obtain the results as a CAD surface. The novelty lies in the utilization of multi-patch IGA models based on NURBS functions, which allows us to simultaneously maximize the stiffness and minimize the volume of the shell by searching for an optimal material distribution within its middle surface. The material is modeled under a small strain assumption in linear elasticity using a Reissner–Mindlin kinematic shell model in plane stress. The effectiveness of our approach is demonstrated on several curved conforming and non-conforming multi-patch geometries in 3D.

Sub-micron colloidosomes with tuneable cargo release prepared using epoxy-functional diblock copolymer nanoparticles

HypothesisPickering emulsions stabilized using epoxy-functional block copolymer nanoparticles should enable the formation of sub-micron colloidosomes that are stable with respect to Ostwald ripening and allow tuneable small-molecule cargo release. ExperimentsEpoxy-functional diblock copolymer nanoparticles of 24 ± 4 nm were prepared via reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization of methyl methacrylate (MMA) in n-dodecane. Sub-micron water-in-n-dodecane Pickering emulsions were prepared by high-pressure microfluidization. The epoxy groups were then ring-opened using 3-aminopropyltriethoxysilane (APTES) to prepare cross-linked colloidosomes. The colloidosomes survived removal of the aqueous phase using excess solvent. The silica shell thickness could be adjusted from 11 to 23 nm by varying the APTES/GlyMA molar ratio. The long-term stability of the colloidosomes was compared to precursor Pickering emulsions. Finally, the permeability of the colloidosomes was examined by encapsulation and release of a small molecule. FindingsThe Pickering emulsion droplet diameter was reduced from 700 to 200 nm by increasing the salt concentration within the aqueous phase. In the absence of salt, emulsion droplets were unstable due to Ostwald ripening. However, emulsions prepared with 0.5 M NaCl are stable for at least one month. The cross-linked colloidosomes demonstrated much more stable than the precursor sub-micron emulsions prepared without salt. The precursor nanoemulsions exhibited complete release (>99 %) of an encapsulated dye, while higher APTES/GlyMA ratios resulted in much lower dye release, yielding nearly impermeable silica capsules that retained around 95 % of the dye.

Enhancing mechanical properties and density of WC-Co with pressureless sintering via shell structure binder jetting additive manufacturing

The binder jetting (BJT) additive manufacturing (AM) process is suitable for producing complex WC-Co cemented carbide parts. To achieve near-full-density in the final parts, the hot isostatic pressing (HIP) sintering process is typically employed to enhance densification. However, HIP sintering requires high equipment specifications and is relatively more costly compared to conventional pressureless sintering. To improve the density of WC-Co parts printed by BJT AM under the pressureless sintering environment, the shell structure printing method was used in this study. The shell structure printing only jets binder to the model's outer profile, creating a shell that encapsulates the central powder, mitigates binder pyrolysis and residual effects on particle densification, and enhances post-sintering density. In this work, the effect of shell thickness, binder type, and printing layer thickness on the density and mechanical properties of the WC-12Co parts under pressureless sintering conditions were investigated. The results show that the density and mechanical properties of the WC-12Co parts significantly improved with the decreasing shell thickness. Specifically, the WC-12Co printed using shell structure achieves a relative density of over 98% and a transverse rupture strength (TRS) of 1954 MPa after pressureless sintering, a result comparable to BJT printed samples treated with HIP sintering. Moreover, the results indicate using a binder with lower residual carbon content and smaller printing layer thickness has a more positive effect on improving density and mechanical strength when employing the shell structure printing method. Microstructure morphology and phase analysis results indicate that the shell structure printing method does not affect the growth of WC grains in the shell and center regions, nor does it influence its phase composition. The shell structure printing method offers a new approach to the manufacturing of near-full-dense WC-Co materials using the BJT process.

Evolution of microstructure and spectral characteristics of silver nanoparticles in photo-thermo-refractive glass

Photo-thermo-refractive (PTR) glass is widely used in volume holographic devices. After photo-thermo treatment, silver nanoparticles (Ag-NPs) and sodium fluoride (NaF) crystals can precipitate in the glass matrix to realize refractive index modulation (RIM). The Ag-NPs are the foundation for subsequent precipitation of NaF crystals and significantly affect the absorption and luminescence characteristics of PTR glass. Within the nucleation temperature range of 440 °C-480 °C, the Ag-NPs formed by photo-thermo-induced nucleation are within 5 nm. Increasing nucleation heat treatment time causes an increase in the average size of Ag-NPs and the thickness of AgBr shell. Increasing the UV exposure dose significantly increases the concentration of Ag-NPs. The long nucleation time and high UV exposure doses can both increase the content of luminescent silver molecular cluster [Agm]n+, while high nucleation temperatures over 500 °C cause fluorescence quenching of PTR glass due to the formation of large Ag-NPs over 10 nm and NaF crystals. The formation of Ag-NPs effectively reduces the crystallization temperature of PTR glass. The refractive index of PTR glass can be effectively controlled by adjusting the parameters of photo-thermo-induced nucleation. Under the condition of crystallization at 550 °C for 30 min, a maximum RIM value of 1500 ppm can be achieved.

Antibubble column: A mean to measure and enhance liquid–gas mass transfer through surfactant-laden interfaces

Antibubbles are ephemeral objects composed of a liquid core encapsulated by a thin gas shell immersed in a liquid bulk. The gas shell thickness evolves in time, driven by two contributions: gravitational drainage and gas–liquid mass transfer. The low density contrast between the antibubble and the bulk, as well as its weak deformability constitute advantages that are used to measure the mass transfer coefficient (MTC) in a so-called antibubble column, in a time-resolved fashion. Shells made with pure air give low data reproducibility. Consequently, perfluorohexane, a low-solubility gas, was mixed to air to enforce gas desorption from the bulk and obtain reliable data. MTC obtained with various surfactants and concentrations are found to deviate from the Frössling correlation built for fully rigid interfaces: higher MTC are consistent with partially rigid interfaces due to a partial coverage of surfactants along a so-called spherical cap, while lower MTC are consistent with an additional resistance to the transfer of mass due to the presence of surfactants forming a monolayer at high concentration. Finally, the advantages in terms of control and compactness of an antibubble column as compared to a bubble column for liquid–gas mass transfer are demonstrated. Specifically, an antibubble is shown to transfer dozens of times more mass than a bubble that would initially carry the same amount of gas. Antibubbles are therefore shown to provide a new, time-resolved, way to measure MTC, as well as promising route to enhance liquid–gas transfers in multiphase reactors.