Hollow Bubbles Research Articles

Experimental and Theoretical Design of Reinforced Bubble Deck Concrete (RBDC) Slab: A Review

Slabs are vital for supporting loads and forming the foundation for structures' floors and roofs, classified as one-way or two-way based on deflection characteristics. A recent innovation in construction, the Reinforced Bubble Deck Concrete (RBDC) slab, integrates spherical or elliptical hollow bubbles within the slab for reinforcement, reducing concrete usage without compromising structural integrity. This unconventional approach diverges from traditional methods. The manuscript thoroughly reviews existing literature on the design and testing of Reinforced Bubble Deck Concrete slabs, aiming to explore their diverse characteristics as observed in international research studies. Findings demonstrate that these slabs offer a sustainable and cost-effective alternative to traditional floor slabs. Their capacity to reduce weight while maintaining strength suggests they could revolutionize construction practices, potentially replacing conventional floor slabs in various projects.

Hollow drop bubbles: A preliminary study of simplified prototype for improving copper(II) extraction with ACORGA® M5640 using coated bubble swarm

There are two well-defined processes for the types of copper ores. One for the processing of copper sulfides and another for the processing of the copper oxides. There are similarities between the two, particularly in the preparation stage of the run of mine (ROM) such as the crushing. However, significant differences exist in how to concentrate the elements of interest. Flotation is the most used concentration process to separate copper sulfide minerals from other minerals using air bubbles. For oxides, after the dissolution of copper, the solvent extraction (SX) process is the preferred path using two immiscible liquids to separate the copper.A line of investigation for solvent extraction is the use of a bubble coated with solvent to extract the metal of interest from the aqueous solution, some devices have been built and tested for this purpose using different principles to generate a coated bubble swarm. However, those equipments have been tested on laboratory and have not been scaled up to an industry level.The Hollow Drop (HD) concept was born from the idea of building a device to generate coated bubbles in a continuous swarm that could be scalable to an industry level. In this paper two columns were built and operated: a proof-of-concept column and a scale-up attempt for the extraction of Cu(II) fom an aqueous solution of 2.5 g L−1 using ACORGA® M5640 (25% v/v) in the Kerosene.The results show that we could generate a bubble swarm and conduct the solvent extraction process at a 97% recovery using our proposed coated bubble generator. However, in our scaled prototype test only a 70% recovery was achieved, which shows that our column is working but the scaling-up needs more investigation regarding the dimensions and flows of the process.

S and O doped porous carbon hollow bubble for Zn ion capacitors with enhanced energy density and long life

Zinc ion capacitors (ZICs) as a promising energy storage systems suffer low energy density and poor cyclic stability, leading to increasing attention to the development of porous carbons. Herein, S and O co-doped porous carbon hollow bubble (S-O-PC-HB) was prepared. The obtained S-O-PC-HB displays 3D porous framework structure to shorten the Zn2+ transport path. S and O dopants introduce more defects and then promote Zn2+ storage capability. The S-O-PC-HB as cathode for ZICs exhibits the largest energy density of 95.68 Wh kg−1 at 178 W kg−1. The assembled ZICs delivers a long cycling stability (92.4 % capacity retention after 20,000 cycles), which presents an alternative practice for high-performance ZICs.

A comparative review on bubble-voided reinforced concrete slab – An innovative concept for lightweight concreting

The bubble-voided reinforced concrete (RC) slab is a relatively new concept of light-weight concreting, introduced to the industry. In this concept, the consumption of unnecessary concrete between the tension zone and the neutral axis, inside a RC slab (one-way or two-way), can be avoided by the introduction of voids at that very zone in the form of hollow plastic bubbles. The bubble-voided slab is lightweight in comparison to the solid slab, and self-weight can effectively decrease upto 30% to 40%, through the application of spherical voided-formers. Although, the bubble-voided slab’s load capacity is slightly less, compared to the equivalent solid slab. But, unlike the hollow-core slab, bubble-voided slab performs well against bi-axial loading. As, the concrete consumption is less in bubble-voided slabs, so less amount of cement needs to be manufactured, and, this way, the bubble-voided concreting method can indirectly be beneficial in reducing the Carbon-Di-Oxide (CO2) emission in the atmosphere. The bubbles can be made of plastic waste, which is an innovative way to recycle that waste plastic to use in industry, and, also reduce plastic wastage from the nature. So, it can be understood that bubble-voided concreting is very much eco-friendly. The present authors have explored through the evolution in the researches on the bubble-voided concrete slab, and, discussed about the critical findings of previous researchers. A comparative discussion is also, presented in this study on various input parameters and load vs deflection curves presented in previous studies. The comparisons showcase that the depth of slab (DS), grade of concrete, and, percentage of void, are the key factors which influence the load vs deflection behaviour of bubble-voided RC slabs. Future scopes in this field of study are identified, such as, studies on the effect of thermal loading, impact loading, and, cyclic loading on the bubble-voided RC slabs.

Computational Analysis of Machining Induced Stress Distribution during Dry and Cryogenic Orthogonal Cutting of 7075 Aluminium Closed Cell Syntactic Foams.

The addition of hollow aluminium oxide bubbles to the 7075 aluminium matrix results in a lightweight syntactic foam with a reduced density and an increased peak compression strength. The presence of ceramic bubbles also aids in a reduced coefficient of thermal expansion and thermal conductivity in comparison to aluminium alloys. In spite of their enhanced material properties, the inclusion of hollow aluminium oxide bubbles presents the challenge of poor machinability. In order to elucidate the problem of poor surface machinability, an attempt has been made to develop a thermo-mechanical finite element machining model using AdvantEdgeTM software with which surface quality and machined syntactic foam material can be analyzed. If the novel model developed is combined with virtual reality technology, CNC technicians can observe the machining results to evaluate and optimize the machining program. The main novelty behind this software is that the material foam is assumed as a homogeneous material model for simplifying the material model as a complex heterogeneous material system. The input parameters used in this study are cutting speed, feed, average size and volume fraction of hollow aluminium oxide bubbles, and coolant. For the output parameters, the numerical analysis showed a 6.24% increase in peak tensile machining induced stress as well as a 51.49% increase in peak cutting temperature as cutting speed (25 m/min to 100 m/min) and uncut chip thickness (0.07 mm to 0.2 mm) were increased. The average size and volume fraction of hollow aluminium oxide bubbles showed a significant impact on the magnitude of cutting forces and the depth of tensile induced stress distribution. It was observed on the machined surface that, as the average size of hollow aluminium oxide bubbles became coarser, the peak machining induced tensile stress on the cut surface reduced by 4.47%. It was also noted that an increase in the volume fraction of hollow aluminium oxide bubbles led to an increase in both the peak machining induced tensile stress and the peak cutting temperature by 29.36% and 20.11%, respectively. This study also showed the influence of the ceramic hollow bubbles on plastic deformation behavior in 7075 aluminium matrix; the machining conditions for obtaining a favorable stress distribution in the machined surface and sub-surface of 7075 closed cell syntactic foam are also presented.

Insight into the effect of clay mineral structure on clay-derived N-doped carbon materials and their efficient electrocatalytic performance

This study aimed to use clay-organic pollutants complex as precursor to fabricate clay-derived N-doped carbon materials, which would reduce the environmental risk of the complex. Kaolinite, sepiolite, montmorillonite as well as iron-saturated montmorillonite were chosen as of the representative clay minerals source. And organic pollutant (tetracycline, TC) was chosen as carbon source. The results revealed the effect of the types of clay minerals and the interaction between TC and clay mineral on the structure and electrocatalytic performance of clay-derived N-doped carbon materials. With the template of layered structural montmorillonite and kaolinite, the obtained carbon materials (NC-MT and NC-KL) possess typically mesoporous structure. With the template of tunnel-like structural sepiolite, NC-SEP exhibited abundant hollow carbon bubbles and mesoporous structure features. Owing to the synergistic effect of iron oxide and montmorillonite in iron-saturated montmorillonite, NC-FEMT showed a graphene-like carbon nanosheet structure with abundant wrinkles and pores. TC might be more easily converted into N-doped clay-derived carbon material, which was partly intercalated into the interlayer of montmorillonite. Besides, the presence of Fe was good for the enhancement of graphitization degree and the generation of active nitrogen species. Moreover, the clay-derived N-doped carbon material presented good oxygen reduction reaction (ORR) electrocatalytic performance.

Mechanical and Physical Characteristics of Bubble Alumina Reinforced Aluminum Syntactic Foams Made Through Recyclable Pressure Infiltration Technique

Metal matrix syntactic foams (MMSFs) are advance hybrid materials which reflect synergetic combination of particle reinforced composites and close cell metal foams. Recently, MMSFs have become considerably popular for several industrial areas because of their low density, high compression strength, good ductility and perfect energy absorption ability. In this paper, Al 7075/bubble alumina syntactic foams were fabricated by recyclable pressure infiltration casting method. Macroscopic and microscopic investigations showed that almost flawless infiltration was obtained between 2 – 4 mm hollow bubble alumina spheres and total porosity values of fabricated foams varied between % 43.2 and % 45.6. As for mechanical analyses, all foam samples were subjected to quasi-static compression test (1 mm/min deformation rate) and their crucial properties such as compression strength, plateau strength, densification strain and energy absorption capacity were determined. Besides, aging heat treatment (T6) was applied to certain samples in order to explore probable effects of heat treatment on the mechanical responses. The outcomes indicated that there was a positive relationship between the aging treatment and compressive features. Under the compressive loading, even though T6 treated foams showed a tendency to brittle fracture, their as-cast variants exhibited ductile behavior.

Intercalation pseudocapacitance of hollow carbon bubbles with multilayered shells for boosting K-ion storage

A novel carbon skeleton constructed by hollow carbon boxes with a unique multilayered shell and an impressive large interlayer spacing of 0.76 nm, inducing the production of intercalation pseudocapacitance and high performance of K-ion storage.

Construction of electrocatalyst based on in-situ growth silver nanoparticles into hollow porous carbon spheres for hydrogen peroxide detection

Considering the natural characteristic and wide application of hydrogen peroxide (H2O2), it is great urgency to design superior electrocatalysts for high-performance determination of H2O2. Herein, silver nanoparticles (AgNPs) embedded into metal–organic frameworks derived hollow porous carbon spheres (HPCS) were successfully constructed and used as a highly sensitive electrochemical sensor. In this architecture, HPCS consisting of continuous hollow carbon bubbles show a highly ordered porous structure between the shells, which can not only provide a large surface area for embedding small size AgNPs and facilitating H2O2 penetration, but also process remarkable electronic conductivity to facilitate the electrochemical redox reaction. The constructed sensor offers a wide linear range of 5 orders magnitude from 0.004 to 17 mM with a detection limit of 0.188 µM and a sensitivity of 637 μA mM−1 cm−2 for H2O2, as well as good selectivity, excellent reproducibility and long-term stability due to a synergistic effect between HPCS and AgNPs, which guarantees the capability, accuracy and reliability of detection H2O2 in the real disinfectant sample. This work could provide an effective load matrix for encapsulating nanoparticles into hollow carbon bubbles, which examined as a superior electrocatalyst for hydrogen peroxide detection platform, showing a great potential for further application in various fields.

ATOMIUM: The astounding complexity of the near circumstellar environment of the M-type AGB star R Hydrae

Evolved low- to intermediate-mass stars are known to shed their gaseous envelope into a large, dusty, molecule-rich circumstellar nebula which typically develops a high degree of structural complexity. Most of the large-scale, spatially correlated structures in the nebula are thought to originate from the interaction of the stellar wind with a companion. As part of the ATOMIUMlarge programme, we observed the M-type asymptotic giant branch (AGB) star R Hydrae with the Atacama Large Millimeter/submillimeter Array. The morphology of the inner wind of R Hya, which has a known companion at ∼3500 au, was determined from maps of CO and SiO obtained at high angular resolution. A map of the CO emission reveals a multi-layered structure consisting of a large elliptical feature at an angular scale of ∼10″ that is oriented along the north–south axis. The wind morphology within the elliptical feature is dominated by two hollow bubbles. The bubbles are on opposite sides of the AGB star and lie along an axis with a position angle of ∼115°. Both bubbles are offset from the central star, and their appearance in the SiO channel maps indicates that they might be shock waves travelling through the AGB wind. An estimate of the dynamical age of the bubbles yields an age of the order of 100 yr, which is in agreement with the previously proposed elapsed time since the star last underwent a thermal pulse. When the CO and SiO emission is examined on subarcsecond angular scales, there is evidence for an inclined, differentially rotating equatorial density enhancement, strongly suggesting the presence of a second nearby companion. The position angle of the major axis of this disc is ∼70° in the plane of the sky. We tentatively estimate that a lower limit on the mass of the nearby companion is ∼0.65 M⊙on the basis of the highest measured speeds in the disc and the location of its inner rim at ∼6 au from the AGB star.

Strain-based tunable hollow-peanut-shaped optical microresonator

A mechanical strain tuning of whispering gallery mode (WGM) in a hollow-peanut-shaped optical microresonator (HPSOM) is demonstrated. The HPSOM is fabricated by fusion splicing two hollow bubbles. The central resonator is formed by the solid structure in the middle, and the near end (far end) resonator is formed by the hollow structure on both sides. The hollow microresonator can improve the strain response-ability compared with the solid micro resonant. The resonator structure and strain response characteristics of the HPSOM are researched theoretically and experimentally researched. It is worth noting that due to the elliptical effect of the central resonator during the manufacturing process, the central resonator cannot confine the light field to the equator and form the WGM. In the coupled spectrum, the WGMs of bilateral HPSOM with low Q-mode are easier to distinguish and monitor. Therefore, a low Q-mode is selected for strain measurement. The testing highest sensitivity is 6.96 pm/μɛ in the strain range 0–25 μɛ. Relative to the large-strain dynamic testing, low-strain testing has broad application prospects in geotechnical engineering testing, structural testing, and engineering geophysical prospecting. Being of general interest, our findings pave the way for improved perception of strain.

Tailoring polysulfide trapping and kinetics by engineering hollow carbon bubble nanoreactors for high-energy Li-S pouch cells

Despite great progress of lithium-sulfur (Li-S) battery performance at the laboratory-level, both key parameters and challenges at cell scales to achieve practical high energy density require high-sulfur-loading cathodes and lean electrolytes. Herein, a novel carbon foam integrated by hollow carbon bubble nanoreactors with ultrahigh pore volume of 6.9 cm3·g−1 is meticulously designed for ultrahigh sulfur content up to 96 wt.%. Tailoring polysulfide trapping and ion/electron transport kinetics during the charge-discharge process can be achieved by adjusting the wall thickness of hollow carbon bubbles. And a further in-depth understanding of electrochemical reaction mechanism for the cathode is impelled by the in-situ Raman spectroscopy. As a result, the as-prepared cathode delivers high specific capacitances of 1,269 and 695 mAh·g−1 at 0.1 and 5 C, respectively. Furthermore, Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm−2 yield exceptional practical energy density of 382 Wh·kg−1 under lean electrolyte of 3.5 µL·mg−1, which demonstrates the great potential for realistic high-energy Li-S batteries.

Bubble Deck Slab as an Innovative Biaxial Hollow Slab – A Review

Slab is the most important member in any building structure which consume large amount of concrete. The slab self-weight is large due to large consumption of concrete in producing slab. Therefore, bubble deck slab is an innovative and newly designed biaxial hollow slab system that had been introduced in order to overcome this problem. Bubble deck slab is a revolutionary method which was developed by Jorgen Bruenig from Denmark in the 1990s. The bubble deck slab had been designed and constructed with plastic hollow bubbles in the middle part of slab to eliminate the concrete which does not perform any structural function and at the same time reducing the slab self-weight. Thus, the self-weight of bubble deck slab can be reduced about 30-50% than conventional concrete slab; that can reduce the loads acting on columns, walls and foundations. Finally, the use of bubble deck slab can give many benefits as compared to conventional concrete slab such as improve the structural performance of slab, reduce the materials and cost, efficiency and faster construction time, and it is also a green product. The aim of this paper is to give some of the reviews from previous studies related to bubble deck slab.

Machining of novel AA7075 foams containing thin-walled ceramic bubbles

ABSTRACT Machining of novel light weight 7075 aluminum alloy reinforced with thin-walled hollow ceramic bubbles present a significant challenge to the manufacturing industry. The presence of hollow bubble phase causes poor surface finish and high machining cost. In this paper, an effort has been made to elucidate the mechanics of machining new grade AA7075 syntactic foams through an analytical force model which is the first of its kind for this material. Orthogonal cutting experiments carried out on different volume fraction and bubble size syntactic foams showed an increase in machining forces by up to 500 N with increasing feed (0.02 mm to 0.2 mm) and 200 N with decreasing cutting speed (100 m/min to 25 m/min). The hollow bubble size profoundly influences the plastic deformation behavior of the matrix. Decrease in average ceramic bubble size (0.6 mm to 0.3 mm) causes the machining forces to increase by margin of 65%. It is found that smaller the hollow bubble size and higher its volume fraction, higher will be the magnitude of machining forces. The causes of variation in machining forces is primary attributed to the characteristic bubble burst modes (Mode 1 and Mode 2) that alters the effective load transfer mechanism with 7075 matrix and its plasticity.

The Dynamic Evolution of Cavitation Vacuolar Cloud with High-Speed Camera

The dynamic model of a single cavitation bubble in the submerged cavitation water jet was established and solved by MATLAB to obtain its motion characteristics and pressure pulse change rules. Numerical simulation based on FLUENT to closer wall, empty bubble breaking form then influences the law of mechanics effect, with the increase in empty bubble, and the breaking time is reduced, but the maximum jet velocity and pressure increase gradually, on the mechanism of action of the solid wall by the fact that the combination of microfluidic and shock wave gradually plays a leading role, while plastic deformation and basic cavitation erosion are avoided. The maximum pressure and maximum jet velocity increase little, and the collapse time of cavitation is reduced. By comparing the grayscale images of the two combinations of jets, it can be found that the brightness of the vacuolar clouds in diameter (d) = 1.6 mm and pressure (P) = 15 MPa is slightly less than that in d = 1.2 mm and P = 30 MPa, indicating that the density of the vacuolar clouds and the dispersion is relatively high, while the increase in nozzle diameter leads to the increase in flow rate, which increases the shear layer of high-speed submerged jet in a static water. The pressure pulse generated by cavitating water jet hollow bubble failure is far greater than the linear superposition value of a single cavitation bubble. But the high-pressure shock wave value on the fixed wall and water hammer pressure are generated by microjet. The conclusion is also corresponding to the simulation results.

N-Doped 3D Interconnected Carbon Bubbles as Anode Materials for Lithium-Ion and Sodium-Ion Storage with Excellent Performance.

In this paper, we develop a novel N-doped 3D interconnected carbon bubbles (NCBs) by a facile method of nitric acid extraction precursor at room temperature for the lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The NCBs with hollow carbon bubbles having a size of ~100 nm interconnected to each other exhibits high specific surface area and abundant active sites, which ensures continuous diffusion paths for ions and electrons and keeps the electrode structure more stable, thus significantly enhancing the lithium-ion and sodium-ion storage capability. In lithium-ion batteries, the NCBs electrode shows a high reversible capacity of 1180 mA h g-1 after 380 cycles at a current density of 1 C. As the current density increased from 1 to 10 C, the capacity still retains 407.1 mA h g-1. While in sodium-ion batteries, the NCBs electrode provides a capacity of 222.5 mA h g-1 after 200 cycles at a current density of 50 mA g-1. And the capacity maintains at 107.5 mA h g-1 even the current density increased from 0.05 to 5 A g-1. The excellent cycling performance and high-rate capability should be attributed to the synergistic effect of the 3D interconnected hollow structure and the incorporation of nitrogen atoms.

Bioinspired Mineralization under Freezing Conditions: An Approach to Fabricate Porous Carbons with Complicated Architecture and Superior K+ Storage Performance.

Bioinspired mineralization is a powerful method for designing and preparing nanomaterials. In this work, we developed a bioinspired mineralization approach under freezing conditions and fabricated methyl cellulose (MC)/NaHCO3 flake precursors with a sophisticated hierarchical structure. Based on this, amazing wing-like porous carbon sheets (WPCSs) assembled by numerous interconnected hollow carbon bubbles were obtained after carbonization and removal of inorganic crystals, which are seldom obtained by other artificial methods. Benefiting from their open framework, large surface area, and enlarged interlayer spacing of graphitized nanocrystallites, the obtained WPCSs exhibited an obvious boost in potassium storage performance. As an anode of potassium-ion batteries, they showed high reversible capacities of 347 mAh g-1 at 50 mA g-1 and 122 mAh g-1 at 20 A g-1 and relatively stable cyclability for 3000 cycles. The assembled WPCS//WPCS potassium-ion hybrid supercapacitor delivered a high energy density of 108 Wh kg-1 at a power density of 280 W kg-1. Given the cost effectiveness and green process, the modified bioinspired mineralization under freezing conditions would provide a facile and green way for exploring porous carbons with controlled structures and rich multifunction.

A Facile Preparation Strategy for TiO2 Spheres by Direct Hydrolysis

AbstractWe have developed a convenient and environmentally benign method for the fabrication of sub‐micron‐sized TiO2 spheres through direct hydrolysis, with the assistance of hollow detergent bubbles as template. The samples obtained at elevated temperatures are firstly characterized by X‐ray diffraction (XRD) and the corresponding photocatalytic activities are evaluated by measuring the photocatalytic oxidation of methyl orange (MO). The results reveal that relative crystallinity and crystallite size have mutual influence on photocatalytic property. Then scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are carried out to investigate the morphology. It can be concluded that hollow templates transform into solid TiO2 products without auxiliary additives. This strategy is quite promising for the low cost, no waste effluent and high productivity, providing a wide range of applications in photocatalysis, catalysis, solar‐cell, separation, and purification processes.

Application of two-color pyrometer for studying of flying luminous particles: Products of alumina laser ablation.

The design of a two-color pyrometer is described, allowing not only measurement of the temperature of a single flying luminous particle with sizes from submicron to millimeters but also the 3D reconstruction of its flight trajectory, the determination of its real velocity, size, frequencies of oscillations of its radiation intensities, and the type of the particle. A distinctive feature of the pyrometer is that two photographs of the flying particle (each in its own spectral band) used for the measurement of particle temperature are made from two mutually perpendicular directions. This device was used to investigate individual condensed particles emitted from the crater by the pulsed laser ablation of alumina. It was found that among the particles the micron and submicron drops are observed as well as the hollow bubbles with diameters up to several millimeters; the drops formed from the boiling and supercooled melt of Al2O3 can be ejected practically at the same time during the laser pulse. The digital processing of the particle streaks has shown that the luminosity of most of the observed particles is isotropic, although the particles radiating nonisotropically are also observed. The radiation of both types of particles may be oscillating. Surprisingly, frequencies of oscillations of the radiation intensity of the flying particle may differ for two channels of the pyrometer registration. The obtained results can be useful to characterize the phase state, properties of alumina particles, and specific features of relaxation of overheated alumina melt. They are interesting both for basic and applied science.

Three-dimensional g-C3N4 aggregates of hollow bubbles with high photocatalytic degradation of tetracycline

A g-C3N4 three-dimensional aggregate composed of hollow bubbles was developed by hydrothermally treating a supramolecular precursor in the presence of a soft template, Pluronic P-123, followed by annealing the obtained intermediate. While, it is found that, without the addition of P123, the obtained g-C3N4 sample consists of sheets. It has been observed that, during the annealing of the intermediate, long balloons were first formed and then transformed into hollow bubbles. And at the P123 mass fraction of 3 wt%, the obtained aggregate is mainly composed of broken hollow bubbles. It has been shown that the three-dimensional hollow bubbles, which was obtained from the intermediate prepared with 2 wt% P123, exhibits large specific surface area and pore volume, enhanced visible-light absorption region, reduced charge recombination, and increased photocurrent response. Consequently, this g-C3N4 material can degrade tetracycline by 97.9% in 12 min under visible light irradiation, which photocatalytic activity is superior to that of all the reported photocatalysts for degradation of tetracycline. It has been elucidated that, •O2− is the main active species, and •OH has been also generated in the reaction system. This work sheds light on the construction of g-C3N4 three-dimensional porous structures with high photocatalytic activity.