Shell Material Research Articles

Acceleration of chondrogenic differentiation utilizing biphasic core-shell alginate sulfate electrospun nanofibrous scaffold

Engineering new biomedical materials with tailored physicochemical, mechanical and biological virtues in order to differentiate stem cells into chondrocytes for cartilage regeneration has garnered much scientific interest. In this study, core/shell nanofibrous scaffold based on poly(ɛ-caprolactone) (PCL) as a core material and alginate sulfate (AlgS)-poly(vinyl alcohol) (PVA) blend as shell materials (AlgS-PVA/PCL) was fabricated by emulsion electrospinning. In this vein, the influence of AlgS to PVA ratio (30:70, 50:50), organic to aqueous phase ratio (1:2, 1:3 and 1:5) and acid concentration (0, 10, 20, 30, 40 and 50 %) on nanofibers morphology were investigated. SEM images depicted that AlgS to PVA ratio of 30:70 and 50:50, organic to aqueous phase ratio of 1:3 and 1:5 and acid concentration of 30 % led to uniform, bead-free fibrous mats. AlgS-PVA/PCL scaffolds with AlgS to PVA ratio of 30:70 and organic to aqueous phase ratio of 1:3, showed admirable mechanical features, high porosity (>90 %) with desirable swelling ratio in wet condition. In vitro assays indicated that the AlgS-PVA/PCL scaffold surface had desirable interaction with stem cells and promotes cells attachment, proliferation and differentiation. Thus, we envision that this salient structure could be an intriguing construction as a cartilage tissue-engineered scaffold.

Heat-treated alginate-polycaprolactone core-shell nanofibers by emulsion electrospinning process for biomedical applications

Fabrication of Core-shell nanofibrous mat which is a promising tool for a wide range of applications in tissue engineering can be developed using water in oil (W/O) or oil in water (O/W) emulsion electrospinning. In this study, for the first time, we fabricated an O/W emulsion-based electrospun core-shell mat using polycaprolactone (PCL) as a core and the blend solution of alginate (Alg) and polyethylene oxide (PEO) as shell material. To achieve a stable core-shell mat, firstly, Alg was modified with heat treatment to decrease the molecular weight of Alg. Then, to improve the chain flexibility of Alg, PEO as a second polymer was added to facilitate its electrospinnability. The different volume ratios of O/W were then fabricated by adding PCL to the Alg-PEO solution to find an optimized emulsion solution. The morphology, swelling, and porosity of the construct were evaluated. At the same time, the mechanical characteristic of fibers was evaluated in both dry and wet conditions. This study also examined cell-scaffold interactions to address the need for a scaffolding material to be suitable for tissue engineering and biomedical applications. Finally, the result exhibited a distinct core-shell structure with better mechanical properties compared to the Alg-PEO.

Damping characteristics of High-Temperature superconducting pinning maglev levitation system

High-temperature superconducting (HTS) pinning maglev has achieved rapid development in recent decades. The levitation system of the HTS pinning maglev is mainly composed of Dewar with built-in HTS bulks and permanent magnet guideway (PMG). For a maglev transportation system, damping is important for vibration attenuation, and the inherent damping characteristics of the HTS pinning maglev system have not been evaluated clearly. In this paper, the damping characteristics of the HTS pinning maglev system are analyzed through experiments and simulations. Experiments are conducted to measure the dynamic responses of the system under free and forced vibrations. The logarithmic envelope method is used to evaluate the system damping under free vibration. The cross-correlation function is utilized to obtain the phase difference between the system vibration signal and excitation signal, and then calculate the system damping under forced vibration conditions. In addition, a two-dimensional finite element model including HTS bulks, PMG, and Dewar conductive shells is established to evaluate the damping force generated by each component during system vibrations. The additional eddy current damping of the conductive Dewar shell is considered and analyzed. Finally, from the perspective of system damping and thermal stability of HTS bulks, suggestions for selecting Dewar shell materials are proposed.

Performance investigations on fluorine-rubber-tube-laying pumping wet shotcrete filled with microencapsulated phase change materials

The challenge of mitigating adverse climatic conditions is a critical issue that affects worker safety and operational efficiency in underground engineering. This study introduces an innovative approach using pumping wet shotcrete as an insulating material, incorporated with microencapsulated phase change materials (MPCMs) and filled within fluorine rubber tubes to address this concern. The MPCMs were synthesized via suspension polymerization, utilizing paraffin as the core material and modified SiO2-poly (lauryl methacrylate) as the shell material. To determine the optimal composition for practical application, an orthogonal experimental design was employed, complemented by comprehensive performance testing. The results indicated that a mix of 1375 kg/m3 of sand, 120 kg/m3 of ceramsite, and 1 g/cm of SiO2-MPCMs in each fluorine rubber tube having an inner diameter of 13 mm, provided the best balance between multiple properties. Notably, the insulation performance improved by 60–75 % compared to traditional pumping wet shotcrete, demonstrating a significant enhancement in thermal management capabilities. The findings contribute substantially to the field of thermal management in mines, presenting a novel technique that could be instrumental in improving safety and efficiency in deep underground operations.

Developments and thermal properties of thermochromic microcapsule and thermochromic asphalt-based composite coatings

The black appearance of asphalt pavement easily absorbs a large amount of solar radiation in hot summer to lower its anti-deformation ability, and asphalt pavement cools down quickly in cold winter to cause cracks. To solve these problems, thermochromic core material (TCM) was encapsulated by the shell material of urea-formaldehyde (UF) resin to prepare thermochromic microcapsule (TM) using situ-polymerization. Then the surface morphology, particle size distribution, chemical composition, phase change property and thermal stability of TM were characterized. After that, emulsified asphalt and acrylic emulsion were selected as film-forming substances to prepare thermochromic asphalt-based composite coating (TACC) after adding different dosages of TM. The surface morphology, chemical composition, thermal storage capacity, phase change property and spectral reflectance of TACC were studied. The results show that TCM is successfully encapsulated by shell material which restricts the thermal conductivity of TCM, making heat transfer process of TM become gentler. Also, the phase change property of TM is still better due to excellent phase change property of TCM. Further, TM particles with the size range of 3.2–4.8 μm are uniformly distributed on TACC surface and show better dispersion in emulsified asphalt. Additionally, TM enhances the thermal storage capacity and thermal stability of TACC. The heat exchange efficiency between asphalt pavement and surrounding environments is increased by added TM particles, improving the thermal stability of TACC. Finally, the increased spectral reflectance in the near-infrared region reflects more solar radiation in hot season because of high reflectivity of TACC on asphalt pavement, which lowers asphalt pavement temperature to improve its anti-deformation ability.

Synthesis and performance optimization of CsPbBr3/CdS core/shell lead halide perovskite nanocrystals by an ion exchange method.

All-inorganic lead halide perovskite nanocrystals (NCs) have excellent optoelectronic properties and promising applications. Improving the stability of inorganic halide NCs and optimizing their photoluminescence quantum yields (PLQY) has become an urgent task. Constructing core-shell structures is an effective method to improve the environmental stability and PLQY, however, realizing core-shell structured perovskite NCs with good dispersion and multiple perovskites encapsulated within the shell material remains challenging. In this work, CdS shells were grown on the surface of CsPbBr3 NCs by ion-exchange method utilizing perovskite NCs with their ionic properties, and the effectiveness of the surface shell protection is reflected in its enhancement of long-term storage stability, storage stability in water, and thermal stability of NCs. In addition, the PLQY and exciton binding energies of CsPbBr3/CdS NCs are increased. Finally, the NCs were packaged into green emitting LED devices and performed high stability. The results will facilitate the further commercialization of all-inorganic lead halide perovskite materials for optoelectronic devices.

Construction of Reverse Type-II InP/ZnxCd1-xS Core/Shell Quantum Dots with Low Interface Strain to Enhance Photocatalytic Hydrogen Evolution.

The InP-based quantum dots (QDs) have attracted much attention in the field of photocatalytic H2 evolution. However, a shell should be used for InP-based photocatalytic systems to passivate the numerous surface defects. Different from the traditional InP-based core/shell QDs with Type-I or Type-II band alignment, herein, the "reverse Type-II" core/shell QDs in which both the conduction and valence bands of shell materials are more negative than those of core materials have been well-designed by regulating the ratio of Cd/Zn of the alloyed ZnxCd1-xS shell. The reverse Type-II band alignment would realize the spatial separation of photogenerated carriers. More importantly, the photogenerated holes tend to rest on the shell in the reverse Type-II QDs, which facilitate hole transfer to the surface, the rate-determining step for solar H2 evolution using QDs. Therefore, the obtained InP/Zn0.25Cd0.75S core/shell QDs exhibit superior photocatalytic activity and stability under visible light irradiation. The rate of solar H2 evolution reaches 376.19 μmol h-1 mg-1 at the initial 46 h, with a turnover number of ∼2,157,000 per QD within 70 h irradiation.

Self‐lubricating polyamide 6 and polyamide 6.6 microcapsule‐based composites

AbstractPolymeric applications with extended service life and low energy loss due to friction are of great interest in conveyor and power transmission technology. Self‐lubricating systems utilizing microcapsules hold significant potential for increasing energy efficiency and extending the operational life of these applications. This study focuses on synthesizing oil‐filled microcapsules through in situ polymerization of polyamide and their incorporation in polyamide 6 and polyamide 6.6. Microcapsules with a core made of thermally stable lubricant Food Lube, and particle diameter D90 of 50 μm were synthesized and isolated as a free‐flowing powder via spray‐drying procedure. The resulting powder demonstrated high thermal stability (loss of 5% at 350°C) due to the high thermal stability of both core and shell materials. A compounding process utilizing a twin‐screw extruder was developed to blend microcapsules into thermoplastic matrices. An injection molding machine forms tension rods. The composites' tribological properties are assessed through ball‐on‐disc tests conducted in both oscillation and rotation. The friction coefficient and wear rate of the composites experience a reduction of 79% and 56% for polyamide 6, as well as 77% and 75% for polyamide 6.6. Mechanical testing of the microcapsule composites reveals a decrease in mechanical properties.

Enhanced UIO-66@PDA/SA hydrogel composite bead soil conditioner exhibiting good water retention, adsorption and efficient recyclability capabilities

A hydrogel composite bead soil conditioner with water retention, adsorption and recyclability properties was developed. The core material of the beads was metal organic framework material UIO-66, while the shell material consisted of polydopamine (PDA) and sodium alginate (SA). Characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) were used to analyze and demonstrate the structure and composition of the composites. The water retention experiment and soil water loss experiments showed that the UIO-66@PDA/SA hydrogel composite beads had a water retention rate of 10.96 % after 300 min and a water evaporation rate of less than 1 % in soil within 4 h, indicating good water retention performance. Adsorption experiments showed that the UIO-66@PDA/SA hydrogel composite beads effectively adsorbed methylene blue (MB) with an equilibrium adsorption amount of 213.79 mg/g. This was a 72.6 % increase compared to pure sodium alginate (SA). They had the highest adsorption capacity of 240.79 mg/g at pH=9 and T = 298.15 K, indicating that alkaline conditions favored the adsorption process. The adsorption process followed the Pesudo-second-order model and exhibited characteristics of the Langmuir adsorption isotherm model. In addition, dynamic adsorption analysis demonstrated that the UIO-66@PDA/SA hydrogel composite beads owned efficient recyclability, and the relative adsorption efficiency remained above 90 % after 4 cycles. This technology offers a cost-effective, uncomplicated, and efficient solution for promoting a healthy soil environment and facilitating agricultural applications.

Application of Johnson's approximation in finite element modeling for electric field‐dependent materials

AbstractJohnson's approximation is implemented in a finite element code to simulate the electric field dependence of a core–shell microstructure material. We show how the microstructure, based here on a 50:50 volume fraction, influences the measured effective permittivity as a function of applied voltage. Using a Johnson's parameter of β = 1.0 × 1010 Vm5/C3, verified from commercial BaTiO3‐based multilayer ceramic capacitors (MLCC), we show how the microstructure and the difference in core and shell conductivities alter the local fields generated and how this influences the voltage dependence of the effective permittivity. Systems that comprise a conductive core‐like material surrounded by a resistive shell experience little or modest voltage dependence due to the shell material providing shielding to large electric fields within the cores. Conversely, if the core material is more resistive than the shell material, substantial voltage dependence occurs with simulations showing over a 50% decrease in the effective permittivity. These simulations give improved understanding of voltage dependence and provide a method to help guide the design of future materials for MLCCs with improved performance.

Eco-Friendly Fungal Chitosan-Silica Dual-Shell Microcapsules with Tailored Mechanical and Barrier Properties for Potential Consumer Product Applications.

Commercial perfume microcapsules are becoming popular across the globe to fulfill consumers' demands. However, most of microcapsules rely on synthetic polymers and/or animal-sourced ingredients to form the shells. Therefore, replacement of the shell materials is imperative to minimize environmental microplastic pollution, as well as to meeting peoples' needs, religious beliefs, and lifestyles. Herein, we report a methodology to fabricate environmentally benign dual-shell (fungal chitosan-SiO2) microcapsules laden with fragrance oil (hexyl salicylate). Anionically stabilized oil droplets were coated with fungal chitosan via interfacial electrostatic interactions at pH 2, which were then covered by an inorganic coating of SiO2 produced via external alkaline mineralization of sodium silicate. Core-shell microcapsules with a spherical morphology were achieved. Under compression, dual-shell chitosan-SiO2 microcapsules yielded a mean nominal rupture stress of 3.0 ± 0.2 MPa, which was significantly higher than that of single-shell microcapsules (1.7 ± 0.2 MPa). After 20 days in neutral pH water, only ∼2.5% of the oil was released from dual-shell microcapsules, while single-shell microcapsules cumulatively released more than 10%. These findings showed that the additional SiO2 coating significantly enhanced both mechanical and barrier properties of microcapsules, which may be appealing for multiple commercial applications, including cosmetics and detergents.

Habitat Provision Differs Across Subtidal Reefs Varying in Location Within the Estuarine Landscape

Although position within the estuarine landscape is known to influence structural characteristics and ecological functioning of many habitats, the influence of position on subtidal oyster reef characteristics and functioning is relatively understudied. This study assessed habitat provision by oysters and benthic macrofauna on subtidal bar and patch oyster reefs within the northwestern Gulf of Mexico estuary. Bar reefs had greater and more variable oyster density, biomass, and volume, as well as dead shell material, compared to patch reefs. Benthic macrofaunal community composition differed between reef types, with bar reefs hosting 11× and 30× higher biomass of Porcellanidae and Ampithoidae crustaceans, and patch reefs supporting 34× and 47× higher biomass of Eunicidae annelids and Leptocheliidae crustaceans. The environmental variables most highly correlated with macrofaunal communities on both bar and patch reefs were sediment chlorophyll-a, volume of dead oyster shells, and depth. Despite differences in structural characteristics and position within the estuarine landscape, subtidal oyster reefs are often managed as a single habitat type. Our findings emphasize the importance of considering location in oyster reef conservation and restoration efforts to better predict and optimize faunal provision outcomes.

Pengaruh Penggunaan Abu Cangkang Terhadap Kuat Tekan Beton

The background of this research is that there is still a lot of oyster shell material that has not been utilized, meanwhile the shell has good mechanical properties as well as concrete. Up to this moment, the shell is not used properly so it needs to studied the use as concrete mixture. By the utilization of this waste is expected to reduce the environmental impact. This study was aims to obtain a regression equation of the compressive strength of concrete using shells, the shells used in this study were oyster shells (ostreidae), tested at 28 days of age with 3 variations in the percentage of the use of shell ash material and with 1 variation of normal concrete. The percentage variations used are 0% variation, 5% variation, 10% variation, and 15% variation. In addition, based on the regression equation, the strong relationship between variables will be obtained which is indicated by the value of r square. The implementation of this research was carried out by carrying out a compressive test of concrete cylinder samples with 3 variations of the water cement rasio (W/C), is W/C 0.4, W/C 0.5, and W/C 0.6. The activity was continued by recording and analyzing data by conducting a regression analysis between the relationship between the percentage of shell use and the compressive strength of concrete. The regression equation used is the exponential regression equation, linear regression, polynomial regression order 2. From the test data, it is found that the regression equation is the best for W/C variation 0.4, obtained polynomial regression equation order 2, y = -0.0351x2 + 0, 3279x + 25.075 with r² = 0.9999, for the W/C variation of 0.5, the second order polynomial regression equation is obtained, y = -0.0702x2 + 0.8062x + 23.406 with r² = 0.8983, and for the W/C variation of 0.6 , the second order polynomial regression equation is obtained, y = -0.0404x2 + 0.4008x + 19.074 with a value of r² = 0.9167..

Preparation of chitosan-hyaluronic acid microcapsules and its dynamic release behavior analysis in a 3D-printed microchannel system: Exploration and verification

This research focuses on the challenges of efficiently constructing drug carriers and evaluating their dynamic release in vitro simulation. By using pickering emulsion and layer-by-layer self-assembly methods. The microcapsules had tea tree oil as the core material, SiO2 nanoparticles as stabilizers, and chitosan and hyaluronic acid as shell materials. The microencapsulation mechanism, as well as the effects of core-shell mass ratio and stirring, were discussed. Specifically, a dynamic circulation simulation microchannel system was designed and manufactured based on 3D printing technology. In this simulation system, the release rate of microcapsules is accelerated and the trend changes, with its behavior aligning with the Boltzmann model. The study demonstrates the advantages of self-assembled inorganic-organic drug-loaded microcapsules in terms of controllable fabrication and ease of functional modification, and shows the potential of 3D printed cyclic microchannel systems in terms of operability and simulation fidelity in drug and physiological analysis.

A Brief Review on the Current Trends in Microencapsulation

Microencapsulation has emerged as a pivotal technology in the field of novel drug delivery systems (NDDS), offering significant advantages in enhancing the efficacy, safety, and patient compliance of therapeutic agents. This cutting-edge technique involves encapsulating active pharmaceutical ingredients (APIs) within microscopic protective coatings, enabling controlled release, targeted delivery, and improved bioavailability. Microencapsulation has proven to be a versatile tool in addressing various pharmaceutical challenges, such as masking unpleasant tastes, protecting sensitive drugs from degradation, and modifying the absorption site of drugs. This comprehensive review aims to provide an in-depth understanding of microencapsulation, its principles, techniques, and diverse applications in the pharmaceutical industry. The article delves into the reasons for employing microencapsulation, including extended or sustained drug release, taste and odor masking, conversion of liquids into free-flowing powders, and stabilization of light, moisture, or oxygen-sensitive drugs. Additionally, the classification of microparticles based on their core and shell materials is discussed. Furthermore, the review explores the advantages and disadvantages of microencapsulation, highlighting its ability to protect encapsulated active agents, transform gases and liquids into solid particles, modify surface and colloidal properties, and alter the release profiles of drugs. Various microencapsulation techniques are extensively covered, including air suspension, coacervation phase separation, pan coating, spray drying and spray congealing, and solvent evaporation. The applications of microencapsulation span across diverse industries, such as pharmaceuticals, cosmetics, agrochemicals, and food. This review provides insights into the utilization of microencapsulated products in these sectors, emphasizing their role in enhancing product functionality, stability, and controlled release

Corrugation parameters and mechanical performance of corrugated shells under the same weight and volume

Cylindrical shells are easy to buckle under external pressure and need to be strengthened before they can be used in engineering. At present, the cylindrical shells are mainly enhanced by welding stiffeners inside them. However, for underwater pressure vessels, it is important to reduce the welding area. Some scholars have proposed various forms of corrugated shells, such as longitudinally corrugated shells, and studied the buckling behavior of corrugated shells under hydrostatic pressure. However, few studies have been conducted on such shells under the same weight conditions. Because an increase in the height of the corrugation necessarily leads to an increase in weight. So this reduces the comparability between the corrugated shells. The mechanism of non-uniform wall thickness on the improvement of shell material utilization is not explained. It is worth exploring how to achieve the best buckling performance under the limited weight. In this paper, the shape parameters of corrugations are explored, including the number, height and width of corrugations, and the coupling between them. The mechanical behavior of corrugated shell is studied from theory, FEA and experiment. In addition to hydrostatic pressure, the collapse of corrugated shells under concentrated pressure is also studied and comparative tests are carried out. The whole process of the collapse of the corrugated shell under concentrated pressure can be directly observed, and this is also an important performance index. In order to ensure the dimensional accuracy of the test samples, 3D printing technology was used for processing. In this paper, higher corrugations are not always better for the same weight. Because corrugation troughs tend to crack before buckling. This is like the short board effect, which requires collaborative optimization of peak and trough thickness.

Scalable Microwires through Thermal Drawing of Co-Extruded Liquid Metal and Thermoplastic Elastomer.

This article demonstrates scalable production of liquid metal (LM)-based microwires through the thermal drawing of extrudates. These extrudates were first co-extruded using a eutectic alloy of gallium and indium (EGaIn) as a core element and a thermoplastic elastomer, styrene-ethylene/butylene-styrene (SEBS), as a shell material. By varying the feed speed of the co-extruded materials and the drawing speed of the extrudate, it was possible to control the dimensions of the microwires, such as core diameter and shell thickness. How the extrusion temperature affects the dimensions of the microwire was also analyzed. The smallest microwire (core diameter: 52 ± 14 μm and shell thickness: 46 ± 10 μm) was produced from a drawing speed of 300.1 mm s-1 (the maximum attainable speed of the apparatus used), SEBS extrusion speed of 1.50 mm3 s-1, and LM injection rate of 5 × 105 μL s-1 at 190 °C extrusion temperature. The same extrusion condition without thermal drawing generated significantly large extrudates with a core diameter of 278 ± 26 μm and shell thickness of 430 ± 51 μm. The electrical properties of the microwires were also characterized under different degrees of stretching and wire kinking deformation which proved that these LM-based microwires change electrical resistance as they are deformed and fully self-heal once the load is removed. Finally, the sewability of these microwires was qualitatively tested by using a manual sewing machine to pattern microwires on a traditional cotton fabric.

Lubrication mechanism of C@Ag core–shell materials as grease additive

The preparation of a low shearing shell on the surface of carbon spheres (CS) is an attractive strategy to improve the lubrication properties of CS. In this study, core–shell structural C@Ag particles were prepared using CS as the hard core and Ag nanoparticles as the soft shell. Then, the additives were mixed with Polyalphaolefin 20 to prepare the C@Ag core–shell-enhanced lithium complex grease (C@Ag-LCG). The physicochemical properties, corrosion resistance, and tribological behaviors of LCGs were investigated. C@Ag-LCG exhibited the best high-temperature resistance and colloidal stability compared with the CS-enhanced lithium complex grease (LCG) and pure LCG. The dropping point and oil separation rate of 0.05 wt% C@Ag-LCG were 255 °C and 2.36 %, respectively. The tribological behavior of greases was tested using a four-ball friction tester, and the main damage mechanism was abrasive wear. The C@Ag additive reduced the average friction coefficient and wear spot diameter by 27.17 % and 26.12 %, respectively. The improved properties were attributed to the synergistic lubrication of hard CS core and soft Ag shell with the rolling, filling, and self-repairing effects, C@Ag deposit films and the self-lubricating oil film, as well as the thickener film and the tribochemical film at the frictional interfaces.

Bayesian batch optimization for molybdenum versus tungsten inertial confinement fusion double shell target design

AbstractAccess to reliable, clean energy sources is a major concern for national security. Much research is focused on the “grand challenge” of producing energy via controlled fusion reactions in a laboratory setting. For fusion experiments, specifically inertial confinement fusion (ICF), to produce sufficient energy, the fusion reactions in the ICF fuel need to become self‐sustaining and burn deuterium‐tritium (DT) fuel efficiently. The recent record‐breaking NIF ignition shot was able to achieve this goal as well as produce more energy than used to drive the experiment. This achievement brings self‐sustaining fusion‐based power systems closer than ever before, capable of providing humans with access to secure, renewable energy. In order to further progress toward the actualization of such power systems, more ICF experiments need to be conducted at large laser facilities such as the United States's National Ignition Facility (NIF) or France's Laser Mega‐Joule. The high cost per shot and limited number of shots that are possible per year make it prohibitive to perform large numbers of experiments. As such, experimental design relies heavily on complex predictive physics simulations for high‐fidelity “preshot” analysis. These multidimensional, multi‐physics, high‐fidelity simulations have to account for a variety of input parameters as well as modeling the extreme conditions (pressures and densities) present at ignition. Such simulations (especially in 3D) can become computationally prohibitive to turn around for each ICF experiment. In this work, we explore using Bayesian optimization with Gaussian processes (GPs) to find optimal designs for ICF double shell targets, while keeping computational costs to manageable levels. These double shell targets have an inner shell that grades from beryllium on the outer surface to the higher Z material molybdenum, as opposed to the nominally used tungsten, on the inside in order to trade off between the high performance associated with high density inner shells and capsule stability. We describe our results for “capsule‐only” xRAGE simulations to study the physics between different capsule designs, inner shell materials, and potential for future experiments.

A step forward towards optimized iron–nickel bimetal oxide core–shell nanoparticles and their magnetic properties

The core–shell nanoparticles of Fe3O4 and NiO are synthesized under different reaction conditions and are characterized by UV–vis and fluorescence spectroscopy, DLS, SEM, EDX, XRD, VSM, and FTIR spectroscopy. These techniques evaluated optimal synthetic conditions for desired size, morphology, stability, and crystallinity of these core–shell nanoparticles. Increasing the concentration of salt for shell material (Fe3O4 or NiO) in core–shell NPs resulted in better coating and increase in hydrodynamic size from 227 nm to 531 nm for (Fe3O4)NiO, and 244 nm to 544 nm for (NiO)Fe3O4, whereas lower concentration and higher temperature (80 °C) for (Fe3O4)NiO and lower temperature (25 °C) for (NiO)Fe3O4, higher pH 13 and 11 for (Fe3O4)NiO and (NiO)Fe3O4 respectively, and fast (quick) addition of reactants produces homogenous small sized nanoparticles. Stability is generally attained at higher concentration, higher temperature (80 °C), higher pH (13 and 11 for (Fe3O4)NiO and (NiO)Fe3O4 respectively), and slow addition (10 min) of reactants. Fluorescence enhancement is observed for (Fe3O4)NiO core–shell NPs at high concentration, temperature, pH and slow addition of reactants, representing proper coating of NiO. For (NiO)Fe3O4 NPs, fluorescence quenching is observed at higher concentration, lower temperature, higher pH, and slow addition of reactants representing proper coating of Fe3O4. XRD depicted pure cubic crystalline nature of these core–shell nanoparticles without any impurity. The identified optimized conditions are useful for obtaining nanoparticles with desired properties for various applications including sensing and catalysis etc. Magnetic properties of pure and core–shell nanoparticles show ferrimagnetic behavior for Fe3O4 NPs and weak ferromagnetic or superparamagnetic behavior NiO NPs.