scholarly journals Core–Shell Droplet Generation Device Using a Flexural Bolt-Clamped Langevin-Type Ultrasonic Transducer

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 55
Author(s):  
Kentaro Omori ◽  
Nozomu Fujimoto ◽  
Takefumi Kanda ◽  
Shuichi Wakimoto ◽  
Norihisa Seno
Keyword(s):  
Silicone Oil ◽  
Ultrasonic Transducer ◽  
Applied Pressure ◽  
Average Diameter ◽  
Vibration Velocity ◽  
Core Shell ◽  
Immiscible Liquids ◽  
Core Phase ◽  
Physical And Chemical ◽  
Type Transducer

Droplets with a core–shell structure formed from two immiscible liquids are used in various industrial field owing to their useful physical and chemical characteristics. Efficient generation of uniform core–shell droplets plays an important role in terms of productivity. In this study, monodisperse core-shell droplets were efficiently generated using a flexural bolt-clamped Langevin-type transducer and two micropore plates. Water and silicone oil were used as core and shell phases, respectively, to form core–shell droplets in air. When the applied pressure of the core phase, the applied pressure of the shell phase, and the vibration velocity in the micropore were 200 kPa, 150 kPa, and 8.2 mm/s, respectively, the average diameter and coefficient of variation of the droplets were 207.7 μm and 1.6%, respectively. A production rate of 29,000 core–shell droplets per second was achieved. This result shows that the developed device is effective for generating monodisperse core–shell droplets.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals Heavy Silicone Oil and Intraocular Inflammation

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Francesco Morescalchi ◽  
Ciro Costagliola ◽  
Sarah Duse ◽  
Elena Gambicorti ◽  
Barbara Parolini ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Molecular Mechanisms ◽  
Silicone Oil ◽  
Surgical Techniques ◽  
Chemical Properties ◽  
Intraocular Inflammation ◽  
Retinal Breaks ◽  
Oxane Hd ◽  
Long Acting ◽  
Physical And Chemical

In the past two decades, many advances have been made in vitrectomy instrumentation, surgical techniques, and the use of different tamponade agents. These agents serve close retinal breaks, confine eventual retinal redetachment, and prevent proliferative vitreoretinopathy (PVR). Long-acting gases and silicone oil are effective internal tamponade agents; however, because their specific gravity is lower than that of the vitreous fluid, they may provide adequate support for the superior retina but lack efficacy for the inferior retina, especially when the fill is subtotal. Thus, a specific role may exist for an internal tamponade agent with a higher specific gravity, such as heavy silicone oils (HSOs), Densiron 68, Oxane HD, HWS 45-300, HWS 46-3000, and HeavySil. Some clinical evidence seems to presume that heavy tamponades are more prone to intraocular inflammation than standard silicone if they remain in the eye for several months. In this review, we discuss the fundamental clinical and biochemical/molecular mechanisms involved in the inflammatory response after the use of heavy tamponade: toxicity due to impurities or instability of the agent, direct toxicity and immunogenicity, oil emulsification, and mechanical injury due to gravity. The physical and chemical properties of various HSOs and their efficacy and safety profiles are also described.

scholarly journals Features of Waste Chemical Processing Germanium Concentrates

2020 ◽  
Author(s):  
Igor Nikolaevich Tanutrov ◽  
Marina Nikolaevna Sviridova
Keyword(s):  
Chemical Properties ◽  
Average Diameter ◽  
Toxic Waste ◽  
High Temperature Treatment ◽  
High Dispersion ◽  
Chemical Processing ◽  
Particle Sizes ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

In order to increase the extraction of germanium in the technology of production of germanium concentrates, as well as finding ways to eliminate the accumulation of toxic waste using modern techniques and equipment, the physical and chemical properties of waste chemical processing of germanium concentrates (OHGC) of two domestic enterprises were experimentally studied. The main components of OHGC are: sulphate hemihydrate CaSO4·0.5H2O and hypochlorite Ca(OCl)2 calcium. The moisture content of the sludge amounted to 30–50 %. The content of germanium in the cakes of both companies is in the range of 0.20 and 0.27 %, respectively, indicating the feasibility of recovery in the Ge. At the same time, the samples of cakes differ significantly in the content of impurities, which depends on the types of raw materials in the preparation of concentrates. Granulometric composition of cakes is characterized by high dispersion. With an average diameter of 12 μm, all particle sizes are in the range of 0.5-15 μm. The distribution of particle sizes is shifted in interval of 0–15 μm, and the area of the particles less than 3 μm is not more than 10 %. The high dispersion of the cake is reflected in the specific surface area, which is 23.7 m2/g. Thermographic study found that the heating of the sample cake is accompanied by two endothermic effects of dehydration at 110 and 145–168 ∘C calcium sulfate and hypochloride semihydrate with corresponding weight loss of 13.1 and 12.9 %. The presence of toxic impurities (arsenic, zinc and lead), as well as chlorine, presents significant challenges for the development of disposal technology with the extraction of germanium. Assuming that the undiscovered part of the germanium in the concentrate is compounds or solid solutions with silicon dioxide, an effective technology should include their reagent high temperature treatment. Keywords: waste, germanium concentrate, chemical processing, waste, physical and chemical properties

Self-Assemble Behavior of Amphiphilic Diblock Copolymer of Methoxy Poly (Ethylene Glycol)/Polyester

2011 ◽  
Vol 295-297 ◽  
pp. 11-15
Author(s):  
Hao Zhou ◽  
Qing Hong Liang ◽  
Xiang Ke Shi ◽  
Li Hua Lu ◽  
Li Qun Zhang ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Light Scattering ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Average Diameter ◽  
Core Shell ◽  
Amphiphilic Diblock Copolymer ◽  
Amphiphilic Diblock Copolymers ◽  
Methoxy Polyethylene Glycol ◽  
Solution Polycondensation

Amphiphilic diblock copolymers based on methoxy polyethylene glycol (MePEG), 1, 6-hexanediol and maleic anhydride with different molar composition were synthesized by solution polycondensation. Self-assemble behavior of amphiphilic diblock copolymer in different solvents by dialyzing technique was discussed. The micelle morphologhy was observed by TEM. It was found that well core-shell MePEG1900/Polyester 2162 copolymer nanoparticles can be formed by self-assemble in acetone solution. In addition, the size of nanospheres measured using dynamic light scattering exhibited a narrow monodisphere size distribution and an average diameter in the ranger of less than 200nm.

Basic Concepts of Nanoemulsion and its Potential application in Pharmaceutical, Cosmeceutical and Nutraceutical fields

2021 ◽  
pp. 3938-3946
Author(s):  
Heba S. Elsewedy ◽  
Bandar E. Al-Dhubiab ◽  
Mahmoud A. Mahdy ◽  
Hanan M. Elnahas
Keyword(s):  
Drug Delivery ◽  
Colloidal Dispersions ◽  
Immiscible Liquids ◽  
Pharmaceutical Dosage Form ◽  
Regulatory Aspects ◽  
Conventional Drug ◽  
Emulsifying Agent ◽  
Basic Concepts ◽  
Physical And Chemical

One of the widely efficient and noteworthy nanocarriers that could draw a great attention toward pharmaceutical fields is nanoemulsions (NEs). NEs are thermodynamically stable colloidal dispersions composed of two immiscible liquids, oil and water that mixed together using emulsifying agent (surfactant and co-surfactant). It regarded as pharmaceutical dosage form having droplet size within a nanometer range, hence it has extensively considered as carrier for delivering active agents. Such carrier is fabricated in order to overcome some obstacles associated with conventional drug delivery systems especially low bioavailability. The objective of this review is to present an overview about NE and its latest applications in diverse areas such as drug delivery, cosmeceutical and nutraceutical. Clarifications about different mechanisms of NEs development that are frequently used were provided. Correspondingly, popular characterization techniques for NEs such as determination of particle size, polydispersity index (PDI), zeta potential and viscosity were reviewed. Eventually, summary of physical and chemical instability in addition to the regulatory aspects of NE were provided.

Silicone Oils and their Properties used in Rhegmatogenous Retinal Detachment Surgery

2019 ◽  
pp. 176-180
Keyword(s):  
Retinal Detachment ◽  
Rhegmatogenous Retinal Detachment ◽  
Silicone Oil ◽  
Chemical Properties ◽  
Retinal Tear ◽  
Giant Retinal Tear ◽  
Silicone Oils ◽  
Medical Indications ◽  
Physical And Chemical ◽  
And Chemical Properties

Silicone oils are polymer structures including siloxane repeats in the center. Copolymers formed by combining these polymers at different ratios constitute different silicone structures with different physical and chemical properties. The presence of several factors such as trauma, giant retinal tear, proliferative vitreoretinopathy and retinal tear in posterior localization is the main medical indications for the use of silicone oils in the surgery of rhegmatogenous retinal detachment. Problems associated with the need for a second surgical intervention to remove silicone oil, the emulsification of silicone oil with the problem this emulsification, and the presence of foreign structure in eye globe are the most important conditions limiting the use of silicone oil.

The Preparation of Core/Shell Particles with Siloxane in the Shell

2005 ◽  
Vol 13 (7) ◽  
pp. 721-726
Author(s):  
Shunsheng Cao ◽  
Xiaobo Deng ◽  
Bailing Liu
Keyword(s):  
Dispersion Medium ◽  
Average Diameter ◽  
Butyl Methacrylate ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron ◽  
Seeding Method ◽  
Emulsion Polymerisation ◽  
Shell Particles ◽  
Methacryloxypropyl Trimethoxysilane

Core-shell microspheres ranging in average diameter from 12.829 to 15.039 μm, with a poly butyl methacrylate (BMA) core, and a poly 3-(methacryloxypropyl)-trimethoxysilane (MATS) shell, were prepared with methanol as the dispersion medium, by a successive seeding method under kinetically controlled conditions. To date, although some of particles (PSi/PA) have been prepared by seeded emulsion polymerisation, only a few core/shell (PA/PSi) microspheres have been reported the literatures. To prepare core/shell (PA/PSi), the core was first synthesized by dispersion polymerisation and to form seeds; addition of MATS monomer was started after 90~95% conversion of the BMA. The reaction was prolonged for another 12 h to achieve complete consumption of MATS monomer. Microspheres; containing hydrophilic PBMA as the core and hydrophobic PMATS as the shell, were successfully formed through the free radical of surface in the core. The particles morphology and size distribution were examined using a Transmission electron microscope and a Malvern Master Sizer/E particle size analyser, respectively.

Preparation and characterization of poly(styrenemethacrylic acid)/MCM-41 core/shell nanocomposite microspheres

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Yansheng Zhao ◽  
Xingji Ma ◽  
Yongmei Liu ◽  
Guangwei Yuan ◽  
Meijuan Guo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cetyltrimethylammonium Bromide ◽  
Average Diameter ◽  
Molar Ratio ◽  
Core Shell ◽  
Acidic Media ◽  
Assembly Method ◽  
20 Nm ◽  
Mcm 41

AbstractIn acidic media, poly(styrene-methacrylic acid)/MCM-41 [P(St- MAA)/MCM-41] core/shell microspheres were synthesized using monodisperse P(St-MAA) particles contained in soap-free emulsion and cetyltrimethylammonium bromide as co-templates by adsorption self-assembly method. The effects of P(St- MAA) composition on shell structure of the core/shell microspheres were investigated. The morphology and composition of P(St-MAA)/MCM-41 microspheres were characterized by TEM, XRD and FTIR. The results show that the ordering degree of MCM-41 shells increased as the molar ratio of MAA to St increased. When n(MAA)/n(St) is 0.2, the average diameter and the shell thickness of nanocomposite microspheres are about 170 nm and 20 nm, respectively.

scholarly journals Empirical modelling and optimization of pressure-coupled infusion gyration parameters for the nanofibre fabrication

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190008 ◽  
Author(s):  
Xianze Hong ◽  
Anthony Harker ◽  
Mohan Edirisinghe
Keyword(s):  
Applied Pressure ◽  
Fibre Diameter ◽  
Morphological Characteristics ◽  
Average Diameter ◽  
Solution Concentration ◽  
Optimal Conditions ◽  
Empirical Modelling ◽  
Average Fibre Diameter ◽  
Poly Ethylene ◽  
Oxide Fibres

Pressure-coupled infusion gyration (PCIG) is a novel promising technique for economical and effective mass production of nanofibres with desirable geometrical characteristics. The average diameter of spun fibres significantly influences the structural, mechanical and physical properties of the produced fibre mats. Having a comprehensive understanding of the significant effects of PCIG experimental variables on the spun fibres is beneficial. In this work, response surface methodology was used to explore the interaction effects and the optimal PCIG experimental variables for achieving the desired morphological characteristics of fibres. The effect of experimental variables, namely solution concentration, infusion (flow) rate, applied pressure and rotational speed, was studied on the average fibre diameter and standard deviations. A numerical model for the interactional influences of experimental variables was developed and optimized with a nonlinear interior point method that can be used as a framework for selecting the optimal conditions to obtain poly-ethylene oxide fibres with desired morphology (targeted average diameter and narrow standard deviation). The adequacy of the models was verified by a set of validation experiments. The results proved that the predicted optimal conditions were able to achieve the average diameter that matched the pre-set desired value with less than 10% of difference.

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