Glass Micro Research Articles

Development of Lightweight Magnesium/Glass Micro Balloon Syntactic Foams Using Microwave Approach with Superior Thermal and Mechanical Properties

Magnesium matrix syntactic foams (MgMSFs) are emerging lightweight materials with unique capabilities to exhibit remarkable thermal, acoustic, and mechanical properties. In the current study, lightweight glass micro balloon (GMB)-reinforced Mg syntactic foams were synthesized via the powder metallurgy technique using hybrid microwave sintering. The processing employed in the study yielded MgMSFs with refined grain sizes, no secondary phases, and reasonably uniform distributions of hollow reinforcement particles. The developed MgMSFs exhibited densities 8%, 16%, and 26% lower than that of the pure Mg. The coefficient of thermal expansion reduced (up to 20%) while the ignition resistance improved (up to 20 °C) with the amount of GMB in the magnesium matrix. The MgMSFs also exhibited a progressive increase in hardness with the amount of GMB. Although the MgMSFs showed a decrease in the yield strength with the addition of GMB hollow particles, the ultimate compression strength, fracture strain, and energy absorption capabilities increased noticeably. The best ultimate compression strength at 321 MPa, which was ~26% higher than that of the pure Mg, was displayed by the Mg-5GMB composite, while the Mg-20GMB composite showed the best fracture strain and energy absorption capability, which were higher by ~39 and 65%, respectively, when compared to pure Mg. The specific strength of all composites remained superior to that of monolithic magnesium. Particular efforts were made in the present study to interrelate the processing, microstructural features, and properties of MgMSFs.

Incorporation of Copper-Doped Mesoporous Bioactive Glass Nanospheres in Experimental Dental Composites: Chemical and Mechanical Characterization.

Experimental dental resin composites incorporating copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) were designed to impart antibacterial and remineralizing properties. The study evaluated the influence of Cu-MBGN on the mechanical properties and photopolymerization of resin composites. Cu-MBGN were synthesized using a microemulsion-assisted sol–gel method. Increasing amounts of Cu-MBGN (0, 1, 5, and 10 wt %) were added to the organic polymer matrix with inert glass micro- and nanofillers while maintaining a constant resin/filler ratio. Six tests were performed: X-ray diffraction, scanning electron microscopy, flexural strength (FS), flexural modulus (FM), Vickers microhardness (MH), and degree of conversion (DC). FS and MH of Cu-MBGN composites with silica fillers showed no deterioration with aging, with statistically similar results at 1 and 28 days. FM was not influenced by the addition of Cu-MBGN but was reduced for all tested materials after 28 days. The specimens with 1 and 5% Cu-MBGN had the highest FS, FM, MH, and DC values at 28 days, while controls with 45S5 bioactive glass had the lowest FM, FS, and MH. DC was high for all materials (83.7–93.0%). Cu-MBGN composites with silica have a potential for clinical implementation due to high DC and good mechanical properties with adequate resistance to aging.

Mechanical behaviour of 3D printed Lightweight Nano-composites

Background: The nanoclay (NC) and glass micro balloons (GMB) based reinforced polymer composites are explored extensively through traditional processing methods. NC shows substantial enhancement in mechanical properties. Polymer composites developed by reinforcing GMB fillers provide a substantial reduction in weight, which is essential in the marine, aerospace, and automotive field. In this study, an attempt is made by developing polymer nano composites by reinforcing NC and GMB particles. Objective: The paper deals with 3 dimensional printing (3DP) of lightweight nanocomposite foam (NF) developed by mixing nanoclay (NC) and glass micro balloons (GMB) in high-density polyethylene (HDPE). The NF blend is prepared by keeping NC at 5 weight %. Subsequently, GMBs are added by volume (20 - 60 %) to NC/HDPE blend to realize lightweight NFs. Methods: The lightweight feedstock filaments are developed by extruding the blends using a single screw extruder. The extruded NF filaments are used as an input in a 3D printer to print NFs. The density of extruded filaments and prints are measured. The printed NFs are subjected to tensile and flexural testing. Conclusion: With an increase in GMB loading the density of both filaments and prints decreases. Compared to neat HDPE, printed NFs show ~30 % weight reducing potential. The tensile, flexural modulus and strength increases with GMB loading. NFs exhibited superior mechanical performance as compared to HDPE and NC/HDPE. Further, the property map reveals that the 3D printed NFs show superior tensile, flexural modulus, and strength in comparison with injection and compression-molded foams.

Hyaluronic acid hydrogels reinforced with laser spun bioactive glass micro- and nanofibres doped with lithium

The repair of articular cartilage lesions in weight-bearing joints remains as a significant challenge due to the low regenerative capacity of this tissue. Hydrogels are candidates to repair lesions as they have similar properties to cartilage extracellular matrix but they are unable to meet the mechanical and biological requirements for a successful outcome. Here, we reinforce hyaluronic acid (HA) hydrogels with 13-93-lithium bioactive glass micro- and nanofibres produced by laser spinning. The glass fibres are a reinforcement filler and a platform for the delivery of therapeutic lithium-ions. The elastic modulus of the composites is more than three times higher than in HA hydrogels. Modelling of the reinforcement corroborates the experimental results. ATDC5 chondrogenic cells seeded on the composites are viable and more proliferation occurs on the hydrogels containing fibres than in HA hydrogels alone. Furthermore, the chondrogenic behavior on HA constructs with fibres containing lithium is more marked than in hydrogels with no-lithium fibres.

Preparation of transgenic Musca domestica by microinjection method

The transposon vector containing enhanced green fluorescent protein (EGFP) was injected into early housefly (Musca domestica L.) eggs by microinjection method to realize stable gene expression in vivo for verification, and to study housefly gene function. A borosilicate glass micro injection needle suitable for microinjection of housefly eggs was made, the softening treatment conditions of housefly egg shells were explored, and a microinjection technology platform suitable for housefly was constructed with a high-precision microsyringe Nanoject Ⅲ as the main body. The recombinant plasmid PiggyBac-[3×P3]-EGFP containing the eye-specific 3×P3 promoter and EGFP and the stable genetic expression helper plasmid pHA3pig helper were microinjected into the treated housefly eggs. After emergence, the eye luminescence was observed, and the expression and transcription level of EGFP were detected. The results showed that the normal hatching rate of housefly eggs was 55% when rinsed in bleaching water for 35 s. The hardness of the egg shell treated for 35 s was suitable for injection and the injection needle was not easy to break. About 3% of the emerged housefly eyes had green fluorescence. Through further molecular detection, EGFP specific fragments with a size of 750 bp were amplified from DNA and RNA of housefly. Through the technical platform, the stable expression of reporter genes in housefly can be conveniently and effectively realized, and a bioreactor with housefly as the main body can be established, which provides certain reference value for subsequent research on housefly gene function.

Glass Micro Balls Based on Glass Domestic Waste for Road Construction

The glass micro balls based on glass domestic waste for road construction were obtained. Glass micro balls will reduce the contamination of road marking and increase its light-reflective ability at night. Colorless and colored container glass, as well as lead crystal, was chosen as the starting material for producing glass micro balls. An electric arc plasmotron UPU-8M was used to produce glass micro balls. Pre-crushed fractionated glass together with plasma-forming gas – argon was fed to the powder feeder and from the feeder to the plasma burner. Under the influence of high plasma temperatures, about 9000-12000K, the particles were melted, followed by cooling in the outgoing flow of plasma-forming gases. Due to high-temperature plasma exposure, partial evaporation of alkaline oxides and lead oxide occurred. Glass micro balls were enriched with the oxides of silicon, aluminum and calcium. This helped to increase the acid and alkali resistance of glass micro balls. The micro hardness, density, and refractive index of glass micro balls were studied. It is shown that glass micro balls have an ideal spherical shape and are x-ray amorphous. Glass micro balls are recommended for use in road construction as a reflective element of road marking.

Porous bioactive glass micro- and nanospheres with controlled morphology: developments, properties and emerging biomedical applications.

In recent years, porous bioactive glass micro/nanospheres (PBGSs) have emerged as attractive biomaterials in various biomedical applications where such engineered particles provide suitable functions, from tissue engineering to drug delivery. The design and synthesis of PBGSs with controllable particle size and pore structure are critical for such applications. PBGSs have been successfully synthesized using melt-quenching and sol-gel based methods. The morphology of PBGSs is controllable by tuning the processing parameters and precursor characteristics during the synthesis. In this comprehensive review on PBGSs, we first overview the synthesis approaches for PBGSs, including both melt-quenching and sol-gel based strategies. Sol-gel processing is the primary technology used to produce PBGSs, allowing for control over the chemical compositions and pore structure of particles. Particularly, the influence of pore-forming templates on the morphology of PBGSs is highlighted. Recent progress in the sol-gel synthesis of PBGSs with sophisticated pore structures (e.g., hollow mesoporous, dendritic fibrous mesoporous) is also covered. The challenges regarding the control of particle morphology, including the influence of metal ion precursors and pore expansion, are discussed in detail. We also highlight the recent achievements of PBGSs in a number of biomedical applications, including bone tissue regeneration, wound healing, therapeutic agent delivery, bioimaging, and cancer therapy. Finally, we conclude with our perspectives on the directions of future research based on identified challenges and potential new developments and applications of PBGSs.

Mechanical and durability properties of cement mortar and concrete reinforced with glass micro fibre

Mechanical and durability properties of cement mortar and concrete reinforced with glass micro fibre

A review on the effects of input parameters & filler composition on delamination during machining of FRP composites

In epoch usage of fibre-reinforced polymer (FRP) material are increasing day by day. Weight sensitive structural components like FRP are utilized in industries like Aerospace, Automobile etc, thus assembly of FRC requires drilling operation. Drilling a FRP is quite tough as drill tool undergo variable opposition while fleeting through the alternate layer of fibre and matrix. Drilling of FRP laminates ends up in fibre peel-up and obtrudes which is known as delamination. Rejections of FRP laminates occur due to delamination. Process input parameter {feed (F), cutting speed (S), drill diameter (D), point angle (θ), drill bits (db), chisel edge (E) and fibre orientation angle (α)} and fillers (glass micro balloon (% GMB), carbon tube nano (%CNT) & shows a large role in reducing delamination in FRP. Various Analytical models and Finite element method exist in the literature to investigate the nature of delamination during drilling of FRP composites but none of the researcher identified method to urge delamination free holes. During this review paper, an in-depth effect of all processes parameter and filler percentage on delamination in drilling of FRP composites is highlighted.

Multifunctional Ca-Zn-Si-based micro-nano spheres with anti-infective, anti-inflammatory, and dentin regenerative properties for pulp capping application.

While pulp capping using a variety of materials has been applied clinically to preserve the health and vitality of the dental pulp and induce dentin repair no material meets all the anti-infection, anti-inflammation, and promoting pulp tissue regeneration criteria. Micro-nano materials of bioactive glasses (BG) with the biocompatibility and osteogenesis-promoting properties were developed for this study using Zn-doped bioactive glass (BGz) micro-nano spheres for dental pulp capping to control infection and inflammation and promote tissue regeneration. Of three key findings, the co-culture of Porphyromonas gingivalis showed that the BGz had an excellent antibacterial effect, and after being stimulated with BGz in vitro, macrophages showed a significant decrease of pro-inflammatory M1 markers compared with the undoped BG group. It is also noted that the conditioned medium derived from BGz-stimulated macrophages could significantly promote mineralized dentin formation of dental pulp cells (DPCs). In rats, acute pulp restoration experiments proved that BGz used as a pulp capping agent had excellent dentin regenerative properties. This work may provide a novel strategy to promote osteo/dentinogenic differentiation through regulating early inflammation, with potential applications in pulp capping.

Manufacturing of 3D Microlens Array Mold on Bulk Metallic Glass by Self-Aligned Multi-Ball Hot Embossing

Bulk metallic glasses (amorphous alloys) exhibiting both high hardness and extraordinary thermoplastic forming ability, are perfect mold material for 3D optical microlens array. However, conventional 3D micro fabrication for metallic glass requires Si templates which are extremely costly and eco-unfriendly to machine and demold. In this study, we report a green and low-cost self-aligned multi-ball hot embossing process to create 3D micro dimple array on metallic glass by replicating spherical crowns of self-aligned precision balls. A 3D metallic glass micro dimple array with aperture of 867.2 μm and surface roughness of 8.2 nm was fabricated in 30 s. Different from conventional hot embossing that material full-filled into mold, the new process enables micro dimple fabrication with different specifications by freely controlling the down displacement of balls. Therefore, the relationship between down displacement and depth of micro dimple was revealed through exploring the material flow behavior by a verified FE model. In addition, to test the feasibility of the fabricated metallic glass mold, a PMMA compound eye structure was embossed and its focusing and imaging performance were subsequently evaluated. This research demonstrates a new manufacturing process for rapid fabrication of 3D microlens arrays metallic glass mold in a neat and economic way.

Hardness of chemically densified Yellow birch in relation to wood density, polymer content and polymer properties

Abstract Density of wood can be increased by filling its porous structure with polymers. Such densification processes aim to increase hardness of wood and are particularly interesting for flooring applications. This study aims to evaluate efficiency of different polymers for chemical densification based on the polymer properties. Yellow birch (Betula alleghaniensis Britt.) was chemically densified with seven monomer mixtures through acrylate monomer impregnation and electron beam in-situ polymerization. Chemical retention and polymer content of densified woods were recorded. Hardness of treated and untreated Yellow birch was measured and compared to hardness of Jatoba (Hymenaea courbaril L.). All densified woods showed higher or comparable hardness to Jatoba. Hardness of densified wood was analyzed in relation to initial density of wood and polymer content of the material using multivariable linear mixed models. Efficiency of polymers for chemical densification was evaluated through effect of polymer content on hardness with interaction coefficients. Polymer films corresponding to monomer impregnating mixtures were prepared through low energy electron beam and characterized by their glass transition temperature, micro hardness, indentation modulus and crosslinking density. Polymers showed statistically significantly different efficiencies and were separated in two main groups. Overall, polymer efficiency increased with increasing glass transition temperature of polyacrylates.

Mechanical behavior of 3D printed syntactic foam composites

A three-dimensional printed (3DP), polymer based syntactic foams are developed using hollow glass micro balloons (GMB) dispersed in high density polyethylene (HDPE). This work presents the buckling and vibration response of 3D printed foams subjected to axial compression. The buckling load is estimated using Modified Budiansky Criteria (MBC) and Double Tangent Method (DTM) through the load–deflection plots. The first three natural frequencies and their mode shapes are computed as a function of axial compressive load. It is noted that the natural frequency reduces with an increase in axial compressive load. It is also observed that with an increase in GMB %, the natural frequencies and critical buckling load increases. In mode-1, the natural frequency decreases in pre-buckling regimes and increases exponentially in post-critical loading conditions. Analytical solutions obtained from the Euler-Bernoulli-beam theory are compared with experimental results. It is noted that the fundamental frequency approaches zero when the axial load is equal to the critical load. The critical buckling load is estimated through the vibration correlation technique and compared with the results obtained using DTM and MBC methods. The property map is plotted for buckling load against the density of various composites.

Intuitionistic Fuzzy C Means Clustering for Lung Segmentation in Diffuse Lung Diseases

Lung segmentation is a challenging task when increased attenuation appears at the periphery of the lungs. In case of increased attenuation, the intensity of the lung tissue closely matches with surrounding non-lung tissues. This paper presents intuitionistic fuzzy c means clustering to segment the lungs with increased attenuation appearing at the border in diffuse lung diseases. In the proposed approach intuitionistic spatial kernel fuzzy c means is employed to obtain the initial lung segment and it is further refined using quick hull and morphological operations. The proposed approach is evaluated on ’TALISMAN’ diffuse lung diseases benchmark dataset. The dataset has 108 high resolution computed tomography scans with different types of diseases such as reticulation, fibrosis, ground glass opacity, consolidation, emphysema, micro and macro nodules. The evaluation results clearly indicate that the proposed approach achieves better segmentation accuracy on lung scans with increased attenuation appearing at the lung border.

Fabrication methods and high-precision diameter control techniques of optical micro-/nanofibers

Owing to their favorable properties including small sizes, tight optical confinement, large fractional evanescent fields, and low waveguiding losses, optical micro-/nanofibers have attracted broad research interest and technological applications in recent years, in which the precision in micro-/nanofiber fabrication is critical to determine their waveguiding properties and performances. Here, we firstly introduce the principles of high-temperature taper drawing of glass fibers. Next, we review typical fabrication methods including flame-heated manual drawing approach, flame-heated mechanical drawing technique, electric-heated mechanical drawing technique and laser-heated mechanical drawing technique. Cons and pros of the above-mentioned techniques are discussed, followed by a brief introduction to the fabrication of polymer micro-/nanofibers. Thirdly, we introduce the principle and techniques of high-precision diameter control in glass micro-/nanofiber fabrication based on a in-situ feedback from the cutoff of high-order waveguiding modes, which can offer a diameter precision down to nanometer level. In addition, several techniques for diameter measurement of a micro-/nanofiber are also introduced. Finally, we end the review with a brief summary in micro-/nanofiber fabrication, as well as an outlook to future possibilities.

Gypsum composites with glass granules

The article explored the possibility of reducing the average density of self-reinforced gypsum composites. Gypsum matrix and glass hollow granules leads to the appearance of a synergistic effect. It manifests itself in the formation of a compacted gypsum reinforced matrix, which is filled with microspheres. This provides a modified gypsum stone with high technical indicators. The volume of use of glass hollow granules is increasing every year, including in the construction industry. This material, unique in its properties, provides very high compressive strength, low water absorption, low heat conductivity, high chemical resistance, and radio transparency for its composite materials. The method of obtaining this light filler is a combination of complex physicochemical and hydrodynamic processes that occur during the formation of hollow balls from microparticles of glass melt. Creating effective composites based on glass micro granules as a component in the molding of gypsum products opens up new possibilities for designers and technologists. This will significantly expand their scope.

Direct replication of a glass micro Fresnel zone plate array by laser irradiation using an infrared transmissive mold.

It is not yet possible to fabricate micrometer-scale, glass optical components with nanometer-scale precision. Glass thermal imprinting enhances production efficiency. However, dimensional changes caused by shrinkage are inevitable because of phase transitions. Replication is very difficult when high-level pitch precision is essential. We used an infrared-transparent silicon mold and a CO2 laser to perform replica-type, thermal surface texturing at the nanoscale level; we analyzed a glass Fresnel zone plate array to this end. The Fresnel zone plate array was 10 × 10 mm2 in area and featured a 20 × 20 array. The individual Fresnel zone plate diameter was 500 µm and had 21 rings of minimum linewidth 2.9 µm and height 737 nm.

Deposition of Cadmium doped Zinc Selenide Thin Films and its Characteristics

Extensive research is being carried out by many researchers for the purpose of developing solar cells and photo-electrochemical cells with II-IV and II-IV-VI compounds. As an attempt to this, CdZnSe thin films with a varying concentration of Cadmium have been deposited on the glass micro slides by employing chemical bath deposition technique, which provides large area deposition for fabricating optoelectronic devices. The growth mechanism and chemical kinetics of these materials have been studied considering its elementary parameters such as basic constituents, molarities, pH of reaction mixture and deposition conditions like temperature time, rotations per minute etc. Composition of the films was estimated by EDAX studies. Thickness of as- deposited films have been measured by weight difference and interferometric method decreases with increasing Cadmium doping. UV-VISIBLE Optical studies show a high absorption coefficient with direct type of transitions. The energy band gap decreased from 2.81ev to 1.72ev as the doping concentration of Cadmium increases from 0 to 1.

Mechanical Properties of Hybrid Glass Micro balloons/Fly Ash Cenosphere Filled Vinyl Ester Matrix Syntactic Foams

Abstract Syntactic foams are synthesized by using pre-fabricated hollow microspheres. Syntactic foams are used as energy absorption sandwich core for several applications like marine, automotive and aerospace. Properties of syntactic foam can be tailored by addition of filler material. In this work hybrid syntactic foam is fabricated by addition of two types of filler materials that are hollow glass microballoons and fly ash cenosphere into vinyl ester matrix at different concentration. The volume fraction of filler content with respect to matrix is fixed to 50% and composition of two fillers varied. Hybridization of two different types of ceramic microballoons in vinyl ester matrix gives maximum 9.58% improvement in impact strength with respect to plane hollow glass microsphere syntactic foam. Enhancement in flexural strength and Flexural modulus observed is 27.7% and 27.16% respectively as compared to plane hollow glass microsphere syntactic foam

Flexural Behavior of Lightweight Concrete Beams Reinforced with GFRP Bars and Effects of the Added Micro and Macro Fiber

This study evaluated the effect of macro steel fiber (SF), micro glass fiber (GF) and micro polypropylene fiber (PF) in lightweight aggregate concrete, (LWAC) beams reinforced with glass fiber reinforced polymer (GFRP) bars. Firstly, concrete mixtures with different volume fractions of GF, PF and SF were tested up to compressive strength, then determine the optimum fiber content GF, PF and SF added into LWAC mix by 0.3%, 0.8% and 0.25% by the volume of concrete, respectively. Meanwhile, eight rectangular cross-section beams with 100 mm (width) × 200 mm (depth) × 1500 mm (length) were tested by four-point bending beam test up to the ultimate load. The GFRP bars were used to reinforce all beams. The failure modes, load-deflection behavior, ductility, flexural capacity and energy absorption were compared in the test results. The experimental results shown added fibers into LWAC improved the flexural capacity, ductility and energy absorption also enhanced moment capacity by 10.07% to 110%. The results indicated that failure modes of GF and PF specimens were in good consistency with the ACI 440.1R-06 predicted failure modes, but for SF specimens, only concrete crushing failure modes accrued. At the end step, the correction factor ( ) obtained from calculated of the experimental results with the flexural capacity according to the ACI 440.1R-06 and ISIS design manual No. 3.