Journal articles: 'Core-shell drop'

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Hsuan, Chung-Yao, Shuhn-Shyurng Hou, and Ta-Hui Lin. "Analysis of Completely Prevaporized Spray Flames with Water/Octane Core/Shell Structured Droplets." Mathematical Problems in Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/584926.

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A series of studies on laminar flame propagation in off-stoichiometric dilute sprays of monodispersed inert or fuel drops had been investigated by large activation energy asymptotics. The present study extends previous theoretical model to consider water/octane core/shell structured drops instead of single-phase drops. The core/shell structured drops are composed of core fluid (water) encased by a layer of shell fluid (n-octane). In this study, we only deal with the case that core/shell structured drops are vaporized completely just at flame location. Namely, the discussions of this paper are restricted to the completely prevaporized mode. By varying parameters of core water radius, core-to-shell ratio, the amount of liquid loading, and the stoichiometric ratio (lean or rich burning), we examine the gasification of core water and shell fuel of core/shell structured drops upstream of the bulk flame and its relation to the internal heat transfer. The effects of drop radius, core-to-shell ratio, liquid loading, and overall heat loss or gain on flame propagation flux are reported and discussed.

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GAO, PENG, and JAMES J. FENG. "Spreading and breakup of a compound drop on a partially wetting substrate." Journal of Fluid Mechanics 682 (July 1, 2011): 415–33. http://dx.doi.org/10.1017/jfm.2011.235.

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The spreading of a compound drop on a partially wetting solid substrate is numerically simulated using a diffuse-interface method. Compared with a simple drop, the spreading of a compound drop exhibits much more complex behaviour. Depending on the core–shell size ratio and the substrate wettability, various flow regimes are identified in which the interfacial morphology evolves in distinct ways. A phase diagram is constructed in the parameter space of the core–shell size ratio and the wetting angle. For relatively small inner drops, the outer interface does not rupture during the spreading and the inner drop either remains suspended and encapsulated or attaches onto the substrate. Otherwise, the compound drop spontaneously breaks up and releases the inner drop into the ambient fluid. Several breakup scenarios are observed depending on the location of the initial rupture. In some regimes, the wetting of the substrate by one fluid can entrap secondary drops of the other, which can either attach to the substrate or stay suspended. The viscosity ratio mainly affects the spreading rate and plays a minor role in the morphology evolution.

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Blanken, Nathan, Muhammad Saeed Saleem, Carlo Antonini, and Marie-Jean Thoraval. "Rebound of self-lubricating compound drops." Science Advances 6, no. 11 (March 2020): eaay3499. http://dx.doi.org/10.1126/sciadv.aay3499.

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Drop impact on solid surfaces is encountered in numerous natural and technological processes. Although the impact of single-phase drops has been widely explored, the impact of compound drops has received little attention. Here, we demonstrate a self-lubrication mechanism for water-in-oil compound drops impacting on a solid surface. Unexpectedly, the core water drop rebounds from the surface below a threshold impact velocity, irrespective of the substrate wettability. This is interpreted as the result of lubrication from the oil shell that prevents contact between the water core and the solid surface. We combine side and bottom view high-speed imaging to demonstrate the correlation between the water core rebound and the oil layer stability. A theoretical model is developed to explain the observed effect of compound drop geometry. This work sets the ground for precise complex drop deposition, with a strong impact on two- and three-dimensional printing technologies and liquid separation.

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Chen, Qiushui, Stefanie Utech, Dong Chen, Radivoje Prodanovic, Jin-Ming Lin, and David A. Weitz. "Controlled assembly of heterotypic cells in a core–shell scaffold: organ in a droplet." Lab on a Chip 16, no. 8 (2016): 1346–49. http://dx.doi.org/10.1039/c6lc00231e.

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Organ in a drop: we use droplet-based microfluidics to fabricate large-scale, monodisperse, portable micro organs, each in an individual drop. We spatially assemble hepatocytes and fibroblasts in a biocompatible core–shell scaffold, forming an artificial liver in each drop, and expressing enhanced liver-specific functions.

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Ahn, Yoolim, Yohwan Park, Jin Young Koo, and Hee Cheul Choi. "Crystallisation of organic molecules with a remarkably suppressed coffee-ring effect by a drop-drying process using binary solvent core–shell droplets." Molecular Systems Design & Engineering 3, no. 4 (2018): 604–8. http://dx.doi.org/10.1039/c8me00026c.

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Qin, Wei Wei, Martin E. Silvestre, and Matthias Franzreb. "Magnetic Microparticles@UiO-67 Core-Shell Composites as a Novel Stationary Phase for High Performance Liquid Chromatography." Applied Mechanics and Materials 703 (December 2014): 73–76. http://dx.doi.org/10.4028/www.scientific.net/amm.703.73.

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Metal-organic framework UiO-67 was explored as a novel stationary phase for high performance liquid chromatography (HPLC). UiO-67 was, for the first time, homogeneously coated on carboxyl functionalized magnetic silica microparticles at low temperature (45 °C) by using a recently introduced liquid phase epitaxy (LPE) process. HPLC runs using the synthesized core-shell microparticles as stationary phase showed baseline separation for three phenol derivatives, applying gradient elution using acetonitrile and water as mobile phase. It also showed that UiO-67 has the largest affinity for 2,6-dichlorophenol among the phenol derivatives tested. The comparison of core-shell microparticles with 20 and 55 layers, respectively, of UiO-67 grown on the magnetic silica core proof that the UiO-67 shell determines separation behavior. Therefore, the use of UiO-67 core-shell microparticles as a stationary phase combines the advantages of a thin, homogenous MOF shell showing fast kinetics and good separation efficiency with the advantages of spherical silica microparticle cores offering high mechanical robustness and moderate pressure drop.

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Gallagher, Samuel Hugh, Olivier Trussardi, Oliver Lipp, and Dominik Brühwiler. "Hollow Silica Cubes with Customizable Porosity." Materials 13, no. 11 (May 29, 2020): 2474. http://dx.doi.org/10.3390/ma13112474.

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Hollow silica cubes were synthesized by a deposition of a thin silica shell onto micrometer-sized hematite cubes. Ordered mesopores with well-defined pore diameters of 2.8 nm and 3.8 nm were introduced into the silica shell by means of pseudomorphic transformation after removal of the hematite core. The particles retained their cubic morphology upon pseudomorphic transformation, allowing for the preparation of close-packed layers of the hollow mesoporous silica cubes by drop-casting and the visualization of the hollow core by focused ion beam scanning electron microscopy.

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Yumozhapova, Natalia V., Andrey V. Nomoev, and Yuri Ya Gafner. "Computer Modeling of the Formation Process of Core-Shell Nanoparticles Cu@Si." Solid State Phenomena 271 (January 2018): 47–50. http://dx.doi.org/10.4028/www.scientific.net/ssp.271.47.

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The process of nanoparticle Cu@Si formation by the molecular dynamic method using MEAM-potentials was studied. Modeling the droplet behavior demonstrates that a core-shell structure with a copper core and a silicon shell can be formed if the drop is in the liquid state, until the material is finally redistributed. The parameters of thermal stability of Cu@Si composite nanoparticles of different sizes have been determined. It is concluded that as the temperature increases, the diffusion of copper atoms to the surface begins, which leads to a change in the structure and the formation of particles with a core of the Cu@Si type.

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Jiang, B., Y. D. Huang, and L. W. Zhao. "Diffusion process of an ink drop in core–shell silica–titania pigment particles." Materials & Design 92 (February 2016): 114–19. http://dx.doi.org/10.1016/j.matdes.2015.12.021.

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Mullis, Andrew M., Oluwatoyin E. Jegede, Timothy D. Bigg, and Robert F. Cochrane. "Dynamics of core–shell particle formation in drop-tube processed metastable monotectic alloys." Acta Materialia 188 (April 2020): 591–98. http://dx.doi.org/10.1016/j.actamat.2020.02.017.

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Yalçın Enis, İpek, and Hande Sezgin. "An investigation of the effect of structural parameters on the impact properties of sandwich-structured shock absorbers." Journal of Structural Engineering & Applied Mechanics 5, no. 3 (September 30, 2022): 170–80. http://dx.doi.org/10.31462/jseam.2022.03170180.

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The purpose of this study is to develop an impact absorber with a core made of sustainable textile waste as an alternative to the conventional honeycomb structure. In this case, the core structure is made of cotton fiber webs recycled from denim waste, and the outer shell is made of polypropylene plates reinforced with carbon, jute, and E-glass woven fabrics. Production of the sandwich structure is carried out using the hot press method. In addition to the fabric types and layer sequences utilized in the outer shell, the geometry of the core structure is altered, and their effect on the drop-weight impact resistance is examined. The prominent results emphasize that the use of high-performance fabrics in the outer shell facing the outer surface increases the impact resistance, and the sizes of the holes to be obtained in the core structure should be optimized in order to be effective in energy absorption. The results reveal that these developed sandwich structures can constitute a promising alternative for the automotive industry.

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Shim, Wonmi, Chan Sik Moon, Hyeonjin Kim, Hyun Su Kim, Haoxiang Zhang, Su Kyung Kang, Pyung Soo Lee, and Sanghyuk Wooh. "Tailoring the Morphology of Supraparticles by Primary Colloids with Different Shapes, Sizes and Dispersities." Crystals 11, no. 2 (January 21, 2021): 79. http://dx.doi.org/10.3390/cryst11020079.

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Surface-templated evaporation driven (STED) method is a promising method to fabricate supraparticles with various sizes, porosities, and shapes by drying colloidal dispersion drops on liquid repellent surfaces. Until now, for the method, only spherical shaped colloidal particles have been used as primary colloids. Here, we introduce six different shapes of nano-colloidal dispersions for the STED method: nanocubics, nanoplates, nanosheets, coffin-shaped nanoparticles (NPs), spherical NPs, and aggregates of NPs. It is confirmed that the shape and size of the primary colloids have little effect for drying the dispersion drop when a single component colloidal dispersion is dried. For heterogeneous supraparticles with composite material assembly, still the shape of the colloids has no influences, while the size and dispersity play roles for tuning the morphology of the supraparticles. From the results, we propose a way to fabricate homogeneous mixture, core/shell, and Janus core/shell structures of the supraparticles depending on the size and dispersity of the mixture colloidal dispersion. Indeed, knowledge on the effects of types of colloids would be of great importance for tailoring supraparticles.

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Cheng, Xiaorong, Yuhua Lu, Shoulin Gu, and Graham Dawson. "MoS2/Au-Sensitized TiO2 Nanotube Arrays with Core–Shell Nanostructure for Hydrogen Production." Nano 12, no. 09 (September 2017): 1750115. http://dx.doi.org/10.1142/s1793292017501156.

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Herein, a TiO2 NTAs-Au-MoS2 core–shell photoanode was constructed with the intention to fulfill the efficient transfer of photo-generated carriers to the photoelectrode’s surface. Au nanoparticles were decorated by a drop casting method, and the MoS2 layer was deposited above the Au nanoparticles using a photoreduction-annealing process. Au nanoparticles were well dispersed on the inner wall of the TiO2 nanotubes and covered by the MoS2 layer, forming a core–shell nanostructure. The MoS2 layer significantly improved the attachment between Au nanoparticles and TiO2 NTAs, resulting in increased PEC stability and performance. Attributed to the excitation of Au nanoparticles’ localized surface plasmon resonance effect and visible light utilization of MoS2, the TiO2 NTAs-Au-MoS2 core–shell photoanode exhibits greatly enhanced photocurrent density. An increase from 67[Formula: see text][Formula: see text]A/cm2 to 234[Formula: see text][Formula: see text]A/cm2 under Xe lamp illumination and from 2.6[Formula: see text][Formula: see text]A/cm2 to 12.6[Formula: see text][Formula: see text]A/cm2 under visible light illumination ([Formula: see text][Formula: see text]nm) compared with the TiO2 NTAs was observed.

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Wu, Peng, Zhi Ming Liu, and Jian Li. "The Preparation and Characterization of Spherical Cellulose Aerogels with Core-Shell Structure." Advanced Materials Research 873 (December 2013): 701–7. http://dx.doi.org/10.4028/www.scientific.net/amr.873.701.

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The spherical cellulose aerogels with core-shell structure were prepared through hanging drop method in a regenerated non-polar solution. The procedures of these aerogels' preparation include solidification in the acetic acid solution to form a hydrogel, solvent exchange with t-butyl alcohol and freeze drying. The spherical cellulose aerogels were obtained with different cellulose solution concentration, and characterized with BET analysis and electron microscopy. Their density and porosity varied linearly with different cellulose content in the initial solution. And the gel shrinkage upon drying was limited to, on average, 7.3%. The density of spherical cellulose aerogel could be reached down to 0.14 g·cm-3 with high specific surface areas up to 210 m2·g-1. The mesopores' diameter of spherical cellulose aerogel at the highest peak in the size distribution curve is focus on 15nm.

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Chen, Yuanzhong, Guobing Lin, and Yangyang Lu. "Deformation and Stability Analysis of a Core Rockfill Dam with Leakage." Shock and Vibration 2022 (August 29, 2022): 1–9. http://dx.doi.org/10.1155/2022/6944442.

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The No. 4 clay core rockfill dam of the Gongming Reservoir experienced leakages when the reservoir water level was low. To analyze the leakage causes, a series of seepage tests were conducted on the dam materials in this paper. And a three-dimensional finite element stress-seepage coupled calculation model of the dam was established to study the deformation and stresses of the dam under the condition of normal storage water level and the sharp drop in the storage level. The test results show that the permeability coefficient of the clay core material is close to that of the dam shell material, resulting in the leakage of the dam under the condition of the low-water level. The simulation results show that the dam deforms a little under the condition of normal storage water level and the sharp drop in the storage level, and the stress distribution under the condition of the sharp drop in the storage level is basically consistent with that under the condition of normal storage water level. The safety factors of the dam under the two conditions meet the requirements of the specification, but the margin of the safety factor is small.

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Boruah, Manash Protim, Pitambar R. Randive, Sukumar Pati, and Suman Chakraborty. "Morpho-dynamic evolution due to inertia-mediated impact of a compound drop on a deep liquid pool." Physics of Fluids 34, no. 3 (March 2022): 032106. http://dx.doi.org/10.1063/5.0085814.

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A compound drop impacting on a liquid pool exhibits intriguing coalescence patterns that are primarily attributable to the complicated interplay of inertia with other physical parameters such as radius ratio of core to shell drop and density and viscosity contrasts of the two fluids. By executing comprehensive numerical investigations, here, we identify three different regimes based on the radius ratio of compound drop, viz., secondary drop pinch-off without bubble bursting, secondary drop pinch-off after bubble bursting, and compound breakage. Our findings also depict a transition in the shape of a secondary droplet from prolate to oblate or vice versa, a phenomenon non-trivially culminated by secondary drop pinch-off timing, neck radius, and amplitude and wavelength of capillary wave propagation. Our results bring out the fact that higher wavelength and amplitude of capillary waves are responsible for secondary drop pinch-off without bubble bursting. Furthermore, in the case of highly viscous core drop and surrounding fluid, we observe both complete and partial coalescence phenomena, which are critically dictated by the confluence of inertia and radius ratio of a compound drop leading to three different regimes, viz., complete coalescence without bubble bursting, complete coalescence with bubble bursting, and partial coalescence with bubble bursting, distinctively different from the observations for single droplet based investigations reported in earlier studies. These implications are likely to be beneficial in illustrating the physical functionalities accompanying the targeted release of encapsulated biological or pathological entities when they are transmitted under the action of an inertial force into another fluidic medium, a paradigm that has hitherto remained unexplored.

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Shen, Zhen Zhong, Liang Zhong, and Xian Dun Chai. "Analysis of Unsteady Seepage Behavior of Rumei High Core Wall Rockfill Dam by FEM." Applied Mechanics and Materials 724 (January 2015): 175–79. http://dx.doi.org/10.4028/www.scientific.net/amm.724.175.

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The Rumei core wall rockfill dam hydropower station is in Lancang River in the Mangkang county of the Tibet autonomous region with maximum height of 315m and crest length of 666.2m. Due to the high core wall rockfill dam has been more than 300m high, water level sudden drawdown of the unsteady seepage condition shall be taken into consideration, according to the given water level drop speed (5m/d) calculate condition, analysis of the seepage field distribution of the different water level, free surface of different time, each material partition of the dam and foundation soil seepage gradient, etc are given. The results showed that the free surface of the upstream dam shell rockfill body dropping fast than the water level dropping speed of the reservoir. The seepage gradient of the upstream shell is very small, which will not cause adverse effect on the upstream dam slope stability. The free surface of the downstream dam shell rockfill body changes little, which will not cause adverse effect on the downstream of the dam slope stability. As the water level falls, the free surface of the core wall dropping speed is slow, far less than the water dropping speed of the reservoir. In the process of emptying reservoir, the free surface of the core wall remains in a high position, which should cause enough attention.

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Son, Nguyen An, Le Viet Huy, Pham Ngoc Son, and Ho Huu Thang. "Application of the collective model to determine some vibrational bands of 140La nucleus." Tạp chí Khoa học 14, no. 9 (September 20, 2019): 59. http://dx.doi.org/10.54607/hcmue.js.14.9.288(2017).

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140La is created from the thermal neutron capture reaction of 139La, which is the product of the fission reaction. It makes some effects into the components of the nuclear reactor core. Understanding the properties and structure of 140La is important in operating the nuclear reactor. Besides that, nuclear structure models are very effective in explaining the properties of nuclear structure. There are many nuclear structure models to solve those problems, such as Liquid Drop Model, Shell Model, Fermi Model, etc. Among them, the Collective Model has been very successful in describing the variety of nuclear properties, especially energy levels in deformed nuclei that the Shell Model and the Liquid Drop Model does not apply. This paper presents the application of the Collective Model to determine some vibrational bands of 140La nucleus. This experiment is performed at channel No.2 of Dalat Research Reactor (DRR), Prompt gamma neutron activation analysis method (PGNAA) is used. The result has found 8 vibrational bands of 140La nucleus. It’s quite relevant to the theoretical calculation. The deviations are less than 1.6 %.

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Adhyapak, Parag, Rohini Aiyer, Sreekantha Reddy Dugasani, Hyeong-U. Kim, Chung Kil Song, Ajayan Vinu, Venkatesan Renugopalakrishnan, et al. "Thickness-dependent humidity sensing by poly(vinyl alcohol) stabilized Au–Ag and Ag–Au core–shell bimetallic nanomorph resistors." Royal Society Open Science 5, no. 6 (June 2018): 171986. http://dx.doi.org/10.1098/rsos.171986.

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We herein report a simple chemical route to prepare Au–Ag and Ag–Au core–shell bimetallic nanostructures by reduction of two kinds of noble metal ions in the presence of a water-soluble polymer such as poly(vinyl alcohol) (PVA). PVA was intentionally chosen as it can play a dual role of a supporting matrix as well as stabilizer. The simultaneous reduction of metal ions leads to an alloy type of structure. Ag(c)–Au(s) core–shell structures display tendency to form prismatic nanostructures in conjunction with nanocubes while Au(c)–Ag(s) core–shell structures show formation of merely nanocubes. Although UV–visible spectroscopy and X-ray photoelectron spectroscopy analyses of the samples typically suggest the formation of both Ag(c)–Au(s) and Au(c)–Ag(s) bimetallic nanostructures, the definitive evidence comes from high-resolution transmission electron microscopy–high-angle annular dark field elemental mapping in the case of Au(c)–Ag(s) nanomorphs only. The resultant nanocomposite materials are used to fabricate resistors on ceramic rods having two electrodes by drop casting technique. These resistors are examined for their relative humidity (RH) response in the range (2–93% RH) and both the bimetallic nanocomposite materials offer optimized sensitivity of about 20 Kohm/% RH and 300 ohm/% RH at low and higher humidity conditions, respectively, which is better than that of individual nanoparticles.

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Miller Bertolami, Marcelo M. "A Red Giants’ Toy Story. II. Understanding the Red-giant Branch Bump." Astrophysical Journal 943, no. 1 (January 1, 2023): 45. http://dx.doi.org/10.3847/1538-4357/acac8a.

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Abstract The Red-Giant Branch Bump (RGBB) is one of the most noteworthy features in the red-giant luminosity function of stellar clusters. It is caused by the passage of the hydrogen-burning shell through the composition discontinuity left at the point of the deepest penetration by the convective envelope. When crossing the discontinuity the usual trend in increasing luminosity reverses for a short time before it increases again, causing a zig-zag in the evolutionary track. In spite of its apparent simplicity the actual physical reason behind the decrease in luminosity is not well understood and several different explanations have been offered. Here we use a recently proposed simple toy model for the structure of low-mass RGs, together with previous results, to show beyond reasonable doubt that the change in luminosity at the RGBB can be traced to the change in the mean molecular weight of the layers on top of the burning shell. And that these changes happen on a nuclear timescale. The change in the effective mean molecular weight, as the burning shell approaches the discontinuity, causes a drop in the temperature of the burning shell which is attenuated by the consequent feedback contraction of the layers immediately below the burning shell. Our work shows that, when applied correctly, including the feedback on the structure of the core together with the increase in the mass of the core, shell-source homology relations do a great quantitative job in explaining the properties of full evolutionary models at the RGBB.

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Su, Yu, Tong Yu, Guicheng Wang, Chunyan Zhang, and Zhiqiang Liu. "Numerical simulation of electrohydrodynamics of a compound drop based on the ternary phase field method." Science Progress 103, no. 1 (November 6, 2019): 003685041988647. http://dx.doi.org/10.1177/0036850419886473.

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Analytical and numerical methods are often used to study the behavior of multiphase fluid under electric field. Compared with analytical methods, numerical methods can simulate the real physical phenomenon of multiphase fluid dynamics in a large deformation range. The finite element method is mainly applied in two-phase fluid currently, although it can be used to analyze the small and large deformation of multiphase fluid under electric field. This article attempts to develop a finite element model of a concentric compound drop immersed in continuous medium under electric field based on the ternary phase field method and simulate the electrohydrodynamics of the compound drop whose core phase, shell phase, and continuous phase are different. The small deformation simulation results of the compound drop under weak electric field are compared with the analytical results of previous researchers from the three aspects, namely, deformation, free charge distribution, and flow pattern. This model is proved to be effective under certain conditions. Based on this premise, the large deformation and breakup of the compound drop under high electric field are further simulated to investigate the mechanism of compound drop breakup preliminarily.

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Lin, Congmei, Feiyan Gong, Zhijian Yang, Xu Zhao, Yubin Li, Chengcheng Zeng, Jiang Li, and Shaoyun Guo. "Core-Shell Structured HMX@Polydopamine Energetic Microspheres: Synergistically Enhanced Mechanical, Thermal, and Safety Performances." Polymers 11, no. 3 (March 26, 2019): 568. http://dx.doi.org/10.3390/polym11030568.

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The solid–solid phase transition, poor mechanical properties, and high sensitivity has impeded further practical applications of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) based polymer bonded explosives (PBXs). To address these issues together, a facile and effective route was employed to achieve a coating of polydopamine (PDA) on the surface of explosive crystals via in situ polymerization of dopamine. Additionally, PBXs based on HMX@PDA microcapsules were prepared with a fluoropolymer as polymer binder. Improved storage modulus, static mechanical strength and toughness, and creep resistance has been achieved in as-prepared PDA modified PBXs. The β-δ phase transition temperature of as-obtained PBXs based on conventional HMX (C-HMX)@PDA was improved by 16.3 °C. The friction sensitivity of the C-HMX based PBXs showed a dramatic drop after the PDA coating. A favorable balance proposed in this paper among thermal stability, mechanical properties, and sensitivity was achieved for C-HMX based PBXs with the incorporation of PDA.

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Yakymovych, A., G. Kaptay, H. Flandorfer, J. Bernardi, S. Schwarz, and H. Ipser. "The nano heat effect of replacing macro-particles by nano-particles in drop calorimetry: the case of core/shell metal/oxide nano-particles." RSC Advances 8, no. 16 (2018): 8856–69. http://dx.doi.org/10.1039/c7ra13643a.

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Kim, Guk Hee, Jaeung Kim, and Sungchan Yun. "The role of viscosity ratio in Janus drop impact on macro-ridge structure." Physics of Fluids 34, no. 5 (May 2022): 052115. http://dx.doi.org/10.1063/5.0094402.

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An interaction of liquid and solid surfaces upon impact has made great progress in understanding the principle behind impinging compound drops, such as single-interface Janus and core–shell configurations, for controlling drop mobility on the surfaces. Despite advancement of recent technologies, fundamentals of how viscosity ratios of Janus drops affect post-impact dynamics on anisotropic surfaces are still unknown. Here, we numerically investigate the asymmetric impact dynamics of Janus drops on a non-wettable ridged surface to demonstrate the feasibility of the separation of the low-viscosity part from the high-viscosity part by reducing the residence time. The separation is investigated for various viscosity ratios, Weber numbers ( We), and initial angle, which are discussed in terms of the temporal evolution of the mass and momentum distributions. A regime map for the separation reveals that the low-viscosity parts are more likely to be separated from high-viscosity parts as the viscosity ratio increases. The phenomenon can be related to a retraction time, which is explained by a hydrodynamic model for the low-viscosity part. This study suggests that We thresholds for the separation can be significantly reduced with the help of center-assisted retraction along the ridge. The asymmetric bouncing of Janus drops on a ridged surface can open up possibilities for the efficient control of liquid separation.

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XIAO, SI, XIONG-RUI SU, XIAO-NIU PENG, and XUE-FENG YU. "CHARGE TRANSFER FROM MONOLAYERED CdSe/ZnS QUANTUM DOTS TO C60." Modern Physics Letters B 23, no. 13 (May 30, 2009): 1663–69. http://dx.doi.org/10.1142/s0217984909019831.

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The interaction between C 60 and quantum dots (QDs) has attracted much attention recently due to its potential applications in solar cells, for example, as a promising renewable energy source. In this paper, monolayer self-assembled CdSe/ZnS core/shell QDs films were prepared and drop-coated with different amounts of C 60. A significant photoluminescence quenching and an emission lifetime reduction were observed in the QDs- C 60 composite films, and the quenching efficiency was increased with the increasing of the C 60 content. Together with the reduced emission lifetime, the results here provide direct evidence for the charge transfer process in the QDs- C 60 system.

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Lee, Woochul, Joohyun Lim, Jin-Kyu Lee, and Jong-In Hong. "Oligothiophene-modified silver/silica core–shell nanoparticles for inhibiting open-circuit voltage drop and aggregation in polymer solar cells." J. Mater. Chem. A 2, no. 37 (2014): 15357–64. http://dx.doi.org/10.1039/c4ta02763a.

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Tang, Sheng, Tong Qi, Dasha Xia, Mengchan Xu, Mengyuan Xu, Anni Zhu, Wei Shen, and Hian Kee Lee. "Smartphone Nanocolorimetric Determination of Hydrogen Sulfide in Biosamples after Silver–Gold Core–Shell Nanoprism-Based Headspace Single-Drop Microextraction." Analytical Chemistry 91, no. 9 (April 15, 2019): 5888–95. http://dx.doi.org/10.1021/acs.analchem.9b00255.

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Kim, Junhee, Sanghoon Jung, Han-Jung Kim, Yoonkap Kim, Chanyong Lee, Soo Min Kim, Donghwan Kim, and Yongseok Jun. "SiNW/C@Pt Arrays for High-Efficiency Counter Electrodes in Dye-Sensitized Solar Cells." Energies 13, no. 1 (December 27, 2019): 139. http://dx.doi.org/10.3390/en13010139.

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Modern energy needs and the pressing issue of environmental sustainability have driven many research groups to focus on energy-generation devices made from novel nanomaterials. We have prepared platinum nanoparticle-decorated silicon nanowire/carbon core–shell nanomaterials (SiNW/C@Pt). The processing steps are relatively simple, including wet chemical etching to form the silicon nanowires (SiNWs), chemical vapor deposition to form the carbon shell, and drop-casting and thermal treatment to embed platinum nanoparticles (Pt NPs). This nanomaterial was then tested as the counter electrode (CE) in dye-sensitized solar cells (DSSCs). SiNW/C@Pt shows potential as a good electrocatalyst based on material characterization data from Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Raman spectroscopy shows that the surface reactivity of the SiNW/C is increased by the decoration of Pt NPs. These data also show that the carbon shell included both graphitic (sp 2 hybridization) and defective (sp 3 hybridization) phases of carbon. We achieved the minimum charge-transfer resistance of 0.025 Ω · cm 2 and the maximum efficiency of 9.46% with a symmetric dummy cell and DSSC device fabricated from the SiNW/C@Pt CEs, respectively.

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Valenza, Fabrizio, Rafal Nowak, Natalia Sobczak, Alberto Passerone, Michele Di Foggia, and Maria Luigia Muolo. "Interactions between Superalloys and Mould Materials for Investment Casting of Turbine Blades." Advances in Science and Technology 70 (October 2010): 130–35. http://dx.doi.org/10.4028/www.scientific.net/ast.70.130.

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The need of increased efficiency of industrial gas turbines comes also through the improvement of the composition of superalloys (addition of new solutes) and of the manufacturing technologies involved in the investment casting process of the turbine blades. Thus, the knowledge of the interactions between the ceramic materials used for casting and the molten superalloys must be deepened in order to minimize the formation of internal defects, to improve the casting surface and to optimize finishing and casting operations. In this work, a study of the wetting behaviour of some Ni- or Co -based superalloys, used for the fabrication of turbine blades, has been performed with reference to the interactions of these alloys in the molten state with the silica-aluminate based ceramic materials forming the shell or the core in the casting process. Wettability tests have been performed by means of the sessile drop method at 1500°C; the characterization of the interfaces between the molten drop and the substrates has been made on solidified sessile drop samples by SEM/EDS analysis to check the final characteristics of the interfaces. The results are discussed in terms of chemical interactions in relation to the processing parameters and as a function of the surface and interfacial energetic properties of the systems.

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Shwartz, Nataliya L., Alla G. Nastovjak, and Igor G. Neizvestny. "Peculiarities of axial and radial Ge–Si heterojunction formation in nanowires: Monte Carlo simulation." Pure and Applied Chemistry 84, no. 12 (May 27, 2012): 2619–28. http://dx.doi.org/10.1351/pac-con-11-12-05.

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The process of axial and radial Si–Ge heterostructure formation during nanowire growth by vapor–liquid–solid (VLS) mechanism was studied using Monte Carlo (MC) simulation. It was demonstrated that radial growth can be stimulated by adding chemical species that decrease the activation energy of precursor dissociation or the solubility of semiconductor material in catalyst drop. Reducing the Si adatom diffusion length also leads to Si shell formation around the Ge core. The influence of growth conditions on the composition and abruptness of axial Ge–Si heterostructures was analyzed. The composition of the GexSi1–x axial heterojunction (HJ) was found to be dependent on the flux ratio, the duration of Si and Ge deposition, and the catalyst drop diameter. Maximal Ge concentration in the HJ is dependent on Ge deposition time owing to gradual changing of catalyst drop composition after switching Ge and Si fluxes. The dependence of junction abruptness on the nanowire diameter was revealed: in the adsorption-induced growth mode, the abruptness decreased with diameter, and in the diffusion-induced mode it increased. This implies that abrupt Ge–Si HJ in nanowires with small diameter can be obtained only in the chemical vapor deposition (CVD) process with negligible diffusion component of growth.

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Liu, Wenzhao, Letian Li, Bing Liu, Rong Liu, Guannan Zhang, and Zhaoyang Wu. "Core/shell colloidal nanoparticles based multifunctional and robust photonic paper via drop-casting self-assembly for reversible mechanochromic and writing." Journal of Colloid and Interface Science 603 (December 2021): 834–43. http://dx.doi.org/10.1016/j.jcis.2021.06.115.

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Liu, Y. F., B. Lakshminarayana, and J. Burningham. "Flow Field in the Turbine Rotor Passage in an Automotive Torque Converter Based on the High Frequency Response Rotating Five-hole Probe Measurement Part II: Flow field at the off-design condition and effects of speed ratio." International Journal of Rotating Machinery 7, no. 4 (2001): 271–84. http://dx.doi.org/10.1155/s1023621x01000239.

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The flow field at the design condition was presented and interpreted in Part I. The flow field at one off-design condition (Speed Ratio 0.065) is presented and interpreted in this part. In addition, the hydraulic performance is analyzed by using flow measurement results both upstream and downstream of the turbine and inside the turbine rotor passage. It is found that at the off-design conditions, especially the near stall condition (Speed Ratio 0.065), most of the pressure drop occurs in the first half of turbine passage. About 82% of the total torque is extracted between the turbine inlet and the middle plane. In addition, the shell develops torque at nearly five times the rate of core. Furthermore, the higher the speed ratio, the higher the total pressure drop. Loss is maximum at the near stall condition and varies almost linearly with the speed ratios. A compromise has to be made between the design and the off-design performance in order to improve the overall performance and fuel economy of torque converters.

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Liu, Yi, Jing Hu, and Zhihui Wu. "Fabrication of Coatings with Structural Color on a Wood Surface." Coatings 10, no. 1 (January 1, 2020): 32. http://dx.doi.org/10.3390/coatings10010032.

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A facile method for the fabrication of colloidal photonic crystal coatings with tunable structural color on a wood surface was presented. The photonic crystal coatings were formed from monodisperse latex spheres composed of poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)). The latex spheres with a hard PSt core and elastomeric P(MMA-AA) shell were prepared using the emulsion polymerization method. The sessile drop method, a rapid single-step self-assembly method through simple evaporation of emulsion, was used to form three-dimensional colloidal crystals. Coatings with brilliant colors and uniform Bragg’s diffraction covering the entire visible region were fabricated by controlling the sphere size. This simple method provided new insight into the development of wood color embellishment.

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Gurskaya, O., E. Dzugkoeva, L. Korobeynikova, V. Mishin, and V. Stogov. "EFFECT OF REPLACING FA STRUCTURAL STEEL ON THE REACTIVITY RESERVE IN THE BN-600 REACTOR." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2020, no. 4 (December 26, 2020): 78–85. http://dx.doi.org/10.55176/2414-1038-2020-4-78-85.

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The current program in Russia to increase the fuel consumption of fast reactors and increase its burn-out causes the transition to new structural materials, which, in turn, leads to changes in the neutron-physical characteristics of reactors. In particular, the drop in the reactivity reserve noted in the BN-600 reactor of the Beloyarsk NPP at the end of 76 operational cycles, as will be shown below, is due to the transition to a new type of shell steel with an increased content of nickel, which strongly affects the reactivity. Design support for the operation of the BN-600 and BN-800 fast reactors, as well as the experiments carried out on them, is performed by IPPE. This article presents the results of a calculated analysis of the expected changes in the reactivity reserve at the end of 76 operational cycles when replacing the shell steel in BN-600. In addition, the influence of experimental assemblies located in the core on the reactivity reserve of the BN-600 is analyzed. Analysis of calculations of the actual loading of the BN-600 reactor at 76 operational cycle using the methods of the 1st-order perturbation theory, strict perturbation theory, and the Monte Carlo method showed that a partial transition at 76 operational cycle to EK-164 shell steel leads to a decrease in the reactivity margin by 0.030±0.004 %Δk/k. Replacement of steel for the entire core will reduce the reactivity margin by ~0.12 %Δk/k, which is confirmed by Monte Carlo calculations. The calculated reactivity margin obtained at the end of 76 operational cycles for the hot state of the BN-600 reactor is in good agreement with the measured reactivity margin.

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35

Burda, Iurii, Michel Barbezat, and Andreas J. Brunner. "The effect of nano- and micron-scale filler modified epoxy matrix on glass-fiber reinforced polymer insulator component behavior." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 235, no. 6 (March 12, 2021): 1287–301. http://dx.doi.org/10.1177/14644207211000775.

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Glass-fiber reinforced polymer (GFRP) composite rods with epoxy matrix filled with electrically nonconducting particles find widespread use in high-voltage electrical insulator applications. The service loads require a range of different, minimum material property values, e.g. toughness, tensile, or compressive strength, but also component-specific performance, e.g. pull-out friction of surface crimped metal fittings or electric breakdown strength. The contribution discusses selected examples of the effects of different particle filler types on the properties of filled epoxy resin as well as on the behavior of GFRP rods with such a matrix. In all investigated systems CaCO3 was used as micron-sized filler, complemented by different amounts of either nanosilica or core-shell rubber (binary filler), or by both, nanosilica and core-shell rubber (ternary filler). With ternary filler combinations at a content of 36 wt%, fracture toughness GIC was improved in nanocomposite epoxy plates and in GFRP rods by 60% and 100%, respectively compared to a matrix with 20 wt% CaCO3 (used as reference system). The glass transition temperature Tg for some ternary systems dropped from 160 °C (for neat epoxy), to approximately 140 °C, the maximum allowed drop in Tg in view of requirements from further processing steps of the electrically insulating components. The ternary fillers yield transfer of the improvements of fracture properties from epoxy nanocomposite plates into the GFRP rods beyond that of the system with CaCO3 filler only. Compressive strength of the GFRP rods was improved by about 20% only for the binary nanosilica and CaCO3 filler, and was not significantly enhanced with the ternary systems. That combination, however, did not yield improvements in toughness beyond the CaCO3-filled nanocomposite plates and rods. With the range of filler types and contents investigated here, it was hence not possible to simultaneously optimize both, fracture toughness and compressive strength of the GFRP insulator rods.

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36

Labeas, G., and Evangelos Ptochos. "Homogenization of selective laser melting cellular material for impact performance simulation." International Journal of Structural Integrity 6, no. 4 (August 10, 2015): 439–50. http://dx.doi.org/10.1108/ijsi-10-2014-0059.

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Purpose – The purpose of this paper is to present, the global behaviour of sandwich structures comprising cellular cores is predicted by finite element (FE) analysis. Two modelling approaches are investigated, providing different levels of accuracy; in both approaches, the sandwich structure is idealised as a layered stack with the skin modelled using shell elements; while the core is either modelled with fine detail using beam micro-elements representing the cell struts, or is modelled by three-dimensional solid elements after an appropriate core homogenisation. Design/methodology/approach – The applied homogenisation methodology, as well as the all important modelling issues are presented in detail. Experimental tests performed using a mass-drop testing machine are used for the successful validation of the simulation models. Findings – It was concluded that the core microscale models having detailed FE modelling of the core unit cells geometry with fine scale beam elements are suitable for the analysis of the core failure modes and the prediction of the basic core stiffness and strength properties. It was demonstrated that the homogenised core model provides significant advantages with respect to computing time and cost, although they require additional calculations in order to define the homogenised stress-strain curves. Research limitations/implications – Special microscale material tests are required for the determination of appropriate materials parameters of the core models, as steel selective laser melting (SLM) microstrut properties differ from the constitutive steel material ones, due to the core manufacturing SLM technique. Stress interactions were not taken into account in the homogenisation, as the applied core material model supports the introduction of independent stress-strain curves; however, the predicted load deflection results appeared to be very close to those obtained from the detailed core micromodels. Originality/value – The paper is original. The dynamic behaviour of conventional sandwich structures comprising conventional honeycomb type cores has been extensively studied, using simple mass-spring models, energy based models, as well as FE models. However, the response of sandwich panels with innovative SLM cellular cores has been limited. In the present paper, novel modelling approaches for the simulation of the structural response of sandwich panels having innovative open lattice cellular cores produced by SLM are investigated.

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Shahriar Sabuktagin, Mohammed, and Khairus Syifa Hamdan. "Large plasmonic absorption enhancement effect of triangular silver nanowires in silicon." Royal Society Open Science 7, no. 7 (July 2020): 191926. http://dx.doi.org/10.1098/rsos.191926.

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Two-dimensional finite difference time domain (FDTD) simulations were performed for evaluating optical absorption enhancement and loss effects of triangular silver (Ag) nanowires embedded in silicon (Si) thin-film photovoltaic device structures. Near-bandgap absorption enhancement in Si was much larger than the reported values of other nanostructures from similar simulations. A nanowire with equal sides of 20 nm length showed 368-fold absorption enhancement whereas only 5× and 15× enhancement were reported for solid spherical and two-dimensional core-shell type nanostructures, respectively. Undesirable absorption loss in the metal of the nanowire was 3.55× larger than the absorption in Si which was comparable to the value reported for the spherical nanoparticle. Interestingly, as the height of the nanowire was increased to form a sharper tip, absorption loss showed a significant drop. For a nanowire with 20 nm base and 20 nm height, absorption loss was merely 1.91× larger than the absorption in Si at the 840 nm plasmon resonance. This drop could be attributed to weaker plasmon resonance manifested by lower metallic absorption in the spatial absorption map of the nanowire. However, absorption enhancement in Si was still large due to strong plasmonic fields at the sharper and longer tip, which was effective in enhancing absorption over a larger area in Si. Our work shows that the shape of a nanostructure and its optimization can significantly affect plasmonic absorption enhancement and loss performance in photovoltaic applications.

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38

Wilson, Michael C., Stephen M. Kenady, and Randall F. Schalk. "Late PleistoceneBison antiquusfrom Orcas Island, Washington, and the biogeographic importance of an early postglacial land mammal dispersal corridor from the mainland to Vancouver Island." Quaternary Research 71, no. 1 (January 2009): 49–61. http://dx.doi.org/10.1016/j.yqres.2008.09.001.

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AbstractABison antiquuscranium and partial skeleton from Ayer Pond wetland on Orcas Island, San Juan Islands, Washington, date to 11,760 ± 7014C yr BP. They lay in lacustrine sediments below peat, unconformably above emergent Everson Glaciomarine Drift (> 12,00014C yr BP). Several bison finds in similar contexts on Orcas and Vancouver Islands dating between 11,750 and 10,80014C yr BP indicate an early postglacial land mammal dispersal corridor with reduced water barriers between mainland and islands. New bison dates and published shell dates allow estimation of early postglacial relative sea-level trends for the San Juans, with a drop below modern datum ∼ 12,00014C yr BP, and assist in evaluation of marine reservoir corrections. Emergence by ∼ 60 m is suggested by data from nearby areas. A tundra-like or meadow community and succeeding open pine parkland before 11,00014C yr BP supported bison but horn-core reduction suggests suboptimal forage or restricted habitat. Expanding mixed-conifer forests after 11,00014C yr BP contributed to bison extirpation. Dispersing ungulates such as bison must have influenced island vegetation establishment and early succession. Possible evidence for butchering by early coastal people adds significance to the Ayer Pond discovery, given its pre-Clovis age.

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Okumu, Fredrick, and Mangaka Matoetoe. "Electrochemical Characterization of Silver-Platinum Various Ratio Bimetallic Nanoparticles Modified Electrodes." Journal of Nano Research 44 (November 2016): 114–25. http://dx.doi.org/10.4028/www.scientific.net/jnanor.44.114.

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Silver-platinum (Ag-Pt) bimetallic nanoparticles (NPs) with varying mole fractions (1:1, 1:3 and 3:1) were prepared by co-reduction of hexachloroplatinate and silver nitrate with sodium citrate. Upon successful formation of monometallic and bimetallic (BM) core shell nanoparticles, cyclic voltammetry (CV) was used to characterize the NPs. The drop coated nanofilms on the GC electrode showed characteristic peaks of monometallic Ag NPs; Ag+/Ag0 redox couple as well as the Pt NPs; hydrogen adsorption and desorption peaks. Varying current trends were observed in the BM NPs ratios as; GCE/Ag-Pt NPs 1:3 > GCE/Ag-Pt NPs 3:1 > GCE/Ag-Pt NPs 1:1. Fundamental electrochemical properties such as; diffusion coefficient (D), electroactive surface coverage, electrochemical band gaps and electron transfer coefficient (α) and charge (Q) were assessed using Randles - Sevcik plot. High charge and surface coverage was observed in GCE/Ag-Pt NPs 1:3 accounting for its enhanced current. GCE/Ag-Pt NPs 3:1 showed high diffusion coefficient while GCE/Ag-Pt NPs 1:1 possessed high electron transfer coefficient, which is facilitated by its heterogeneous rate constant relative to other BM NPs ratios. Surface redox reaction was determined as adsorption controlled in all modified GCEs.

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Sui, Zhihui, Jinglong San, Xuedong Wu, Jingbin Zhang, and Lingfang Sun. "Preparation and Properties of Nano-ZnO/ Organic Fluorine Modified Polyacrylate Finishing Agent." Journal of the American Leather Chemists Association 115, no. 6 (June 1, 2020): 207–14. http://dx.doi.org/10.34314/jalca.v115i6.3823.

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A nano-ZnO/organic fluorine-modified polyacrylate leather finishing agent was prepared using a mixture of a Silyl-modified nano-ZnO, dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA) and butyl acrylate (BA) as raw materials. A semi-continuous seeded emulsion polymerization followed. The overall research objective was to improve the bacteriostatic, hydrophobicity and anti-aging properties of leather articles. The structure of the composite emulsion and its film were characterized and analyzed by FT-IR, TEM and XPS. The results showed that the latex particles had an obvious core-shell structure, a smooth surface and were monodisperse. The particle size of the emulsion ranged between 30 and 50 nm. The average value of Zeta potential was -40.1 mV which signified a good emulsion stability. The composite emulsion and its film had good UV resistance and water resistance. When the content of organic fluorine in the film was a maximum 20 %, the contact angle of a water drop on the finished leather, tensile strength and tear strength were 133.48°, 620 N and 61 N, respectively. When the content of nano-ZnO in the film was 1.0%, the average width of antibacterial band of finished leather was 2.1 mm. The finished leather also demonstrated a good anti-aging property.

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Chajanovsky, Itamar, and Ran Y. Suckeveriene. "Preparation of Hybrid Polyaniline/Nanoparticle Membranes for Water Treatment Using an Inverse Emulsion Polymerization Technique under Sonication." Processes 8, no. 11 (November 20, 2020): 1503. http://dx.doi.org/10.3390/pr8111503.

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This manuscript describes a novel in situ interfacial dynamic inverse emulsion polymerization process under sonication of aniline in the presence of carbon nanotubes (CNT) and graphene nanoparticles in ethanol. This polymerization method is simple and very rapid (up to 10 min) compared to other techniques reported in the literature. During polymerization, the nanoparticles are coated with polyaniline (PANI), forming a core-shell structure, as confirmed by high-resolution scanning electron microscopy (HRSEM) and Fourier-Transform Infrared (FTIR) measurements. The membrane pore sizes range between 100–200 nm, with an average value of ~119 ± 28.3 nm. The film resistivity decreased when treated with alcohol, and this behavior was used for selection of the most efficient alcohol as a solvent for this polymerization technique. The membrane permeability of the PANI grafted CNT was lower than the CNT reference, thus demonstrating better membranal properties. As measured by water permeability, these are ultrafiltration membranes. An antimicrobial activity test showed that whereas the reference nanoparticle Bucky paper developed a large bacterial colony, the PANI grafted CNT sample had no bacterial activity. The thicker, 2.56 mm membranes exhibited high salt removal properties at a low pressure drop. Such active membranes comprise a novel approach for future water treatment applications.

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42

Summa, Alexander, Hans-Thomas Janka, Florian Hanke, Tobias Melson, Andreas Marek, and Bernhard Müller. "Exploring the physics of core-collapse supernovae with multidimensional simulations: from axisymmetry to three dimensions." Proceedings of the International Astronomical Union 12, S329 (November 2016): 449. http://dx.doi.org/10.1017/s174392131700117x.

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AbstractMultidimensional effects are essential for the success of the neutrino-driven explosion mechanism of core-collapse supernovae. Although astrophysical phenomena in nature involve three spatial dimensions, the huge computational demands still allow only for a few self-consistent, three-dimensional (3D) simulations focusing on specific aspects of the explosion physics, whereas systematic studies of larger sets of progenitor models or detailed investigations of different explosion parameters are restricted to the axisymmetric (2D) modeling approach at the moment. Employing state-of-the-art neutrino physics, we present the results of self-consistent core-collapse supernova simulations performed with the Prometheus-Vertex code in 2D and 3D. The 2D study of 18 successfully exploding pre-supernova models in the range of 11 to 28 solar masses shows the progenitor dependence of the explosion dynamics: if the progenitor exhibits a pronounced decline of the density at the Si/Si-O composition shell interface, the rapid drop of the mass-accretion rate at the time the interface arrives at the shock induces a steep reduction of the accretion ram pressure. This causes a strong shock expansion supported by neutrino heating and thus favors an early explosion. In case of a more gradually decreasing accretion rate, it takes longer for the neutrino heating to overcome the accretion ram pressure and explosions set in later. By considering the effects of turbulent pressure in the gain layer, we derive a generalized condition for the critical neutrino luminosity that captures the explosion behavior of all models very well. We show that this concept can also be extended to describe the effects of rotation as well as the behavior of recent 3D simulations and that the conditions necessary for the onset of explosion can be defined in a similar way.

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Fasolato, Luca, Massimiliano Magro, Giorgio Cozza, Ferruccio Sbarra, Simone Molinari, Enrico Novelli, Fabio Vianello, and Andrea Venerando. "An Iron Shield to Protect Epigallocatehin-3-Gallate from Degradation: Multifunctional Self-Assembled Iron Oxide Nanocarrier Enhances Protein Kinase CK2 Intracellular Targeting and Inhibition." Pharmaceutics 13, no. 8 (August 16, 2021): 1266. http://dx.doi.org/10.3390/pharmaceutics13081266.

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Protein kinase CK2 is largely involved in cell proliferation and apoptosis and is generally recognized as an Achilles’ heel of cancer, being overexpressed in several malignancies. The beneficial effects of (−)-epigallocatechin-3-gallate (EGCG) in the prevention and treatment of several diseases, including cancer, have been widely reported. However, poor stability and limited bioavailability hinder the development of EGCG as an effective therapeutic agent. The combination of innovative nanomaterials and bioactive compounds into nanoparticle-based systems demonstrates the synergistic advantages of nanocomplexes as compared to the individual components. In the present study, we developed a self-assembled core-shell nanohybrid (SAMN@EGCG) combining EGCG and intrinsic dual-signal iron oxide nanoparticles (Surface Active Maghemite Nanoparticles). Interestingly, nano-immobilization on SAMNs protects EGCG from degradation, preventing its auto-oxidation. Most importantly, the nanohybrid was able to successfully deliver EGCG into cancer cells, displaying impressive protein kinase CK2 inhibition comparable to that obtained with the most specific CK2 inhibitor, CX-4945 (5.5 vs. 3 µM), thus promoting the phytochemical exploitation as a valuable alternative for cancer therapy. Finally, to assess the advantages offered by nano-immobilization, we tested SAMN@EGCG against Pseudomonas aeruginosa, a Gram-negative bacterium involved in severe lung infections. An improved antimicrobial effect with a drastic drop of MIC from 500 to 32.7 μM was shown.

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Jebur, Khalid H., and Nadheer Jassim Mohammed. "Dependence of The Structural and Optical Properties of Gallium Oxide Nanostructures on Laser Fluency." Al-Mustansiriyah Journal of Science 32, no. 4 (November 20, 2021): 60–66. http://dx.doi.org/10.23851/mjs.v32i4.993.

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In this research, thin films of gallium oxide β-Ga₂O₃ nanostructures were prepared by pulsed laser ablation in distilled water (PLAL), then deposited on quartz substrate by the drop-casting method at 90 oC. The Nd-YAG laser was used with a wavelength of 1064 nm and a repetition rate of 5 Hz. The effect of increasing laser fluencies on the structural and optical properties was investigated by, Transmission electron microscope (TEM), Atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer microscopy (UV-VIS). Crystallite size for all samples increased with the increasing the fluency of laser excepting at the fluency of laser 5.57 J/cm2 was 9.78 nm. The formation of nanoparticles, spindle-like, nanosheet and core-shell of β-Ga₂O₃ have been observed by the images of TEM at the fluencies of laser 4.77, 5.57, 5.97, and 6.36 J/cm2, respectively. The nanocluster and nanoroads of the β-Ga₂O₃ thin films can be seen by the SEM images at the all fluencies of laser 4.77, 5.97, 6.36 and 5.57 J/cm2. The‏ ‏‎ results of XRD investigations showed‏ that the diffractions patern of β-Ga₂O₃ transformed from the monoclinic phase with (-201), ‎‎(-402), and (-603) into orthorhombic phase with (002), 004), and (006) when increased ‎the fluency of laser.‎‏‎ The energy bandgap decreased with the increase of laser fluencies, and the absorption peak was located in the UV region.

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SHIMKO, Oleg V. "Profitability ratios of the world's leading publicly traded oil and gas corporations as an indicator of the investment attractiveness of domestic vertically integrated oil and gas companies." Economic Analysis: Theory and Practice 21, no. 8 (August 30, 2022): 1506–17. http://dx.doi.org/10.24891/ea.21.8.1506.

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Subject. The article focuses on the key profitability ratios of twenty five leading publicly traded oil and gas companies from 2006 through 2018. The analysis encompasses ExxonMobil, Chevron, ConocoPhillips, Occidental Petroleum, Devon Energy, Anadarko Petroleum, EOG Resources, Apache, Marathon Oil, Imperial Oil, Suncor Energy, Husky Energy, Canadian Natural Resources, Royal Dutch Shell, BP, TOTAL, Eni, Equinor (Statoil), PetroChina, Sinopec, CNOOC, Petrobras, PAO Gazprom, PAO NK Rosneft, and PAO LUKOIL. Objectives. The aim of the study is to trace key trends in key profitability ratios of corporations in the oil and gas industry, to identify the key trends in their change within the studied period, and to establish those factors that led to this transformation. Methods. The study is based on methods of comparative and financial-economic analysis, summarizing financial reporting data. Results. I determined the dynamics of changes in key profitability indicators in the stock market sector of the industry and established the main factors that contributed to this transformation, based on the results of a comprehensive analysis of balance sheets of 25 oil and gas companies. I revealed a decrease in the profitability of the leading publicly traded oil and gas companies within the studied period, which was especially clearly manifested in the midst of the global financial and industry crises. The most difficult situation is observed in a number of independent US companies. The main reason for the drop in the profitability of the stock market sector of the industry is that the costs of core activities outstrip the corresponding revenue in terms of growth, mainly due to the costs of depreciation, depletion, and amortization. Another important factor was a significant increase in the book value of non-current assets. The study unveils that the specific burden of income tax per unit of net revenue from core activities is gradually decreasing in the stock market sector of the oil and gas industry. Conclusions. The profitability of the oil and gas stock market sector is deteriorating, however, the current price level allows the leading companies to generate net income.

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Pinçon, C., M. Takata, and B. Mosser. "Evolution of the gravity offset of mixed modes in RGB stars." Astronomy & Astrophysics 626 (June 2019): A125. http://dx.doi.org/10.1051/0004-6361/201935327.

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Context.Observations of mixed modes in evolved low-mass stars enable us to probe the properties of not only the outer envelope of these stars, but also their deep layers. Among the seismic parameters associated with mixed modes, the gravity offset, denoted withεg, is expected to reveal information on the boundaries of the inner buoyancy resonant cavity. This parameter was recently measured for hundreds of stars observed by theKeplersatellite and its value was shown to change during evolution.Aims.In this article, we theoretically investigate the reasons for such a variation in terms of structure properties, focusing only on the red giant branch.Methods.Using available asymptotic analyses and a simple model of the Brunt–Väisälä and Lamb frequencies in the upper part of the radiative zone, we derived an analytical expression ofεgfor dipolar modes and compared its predictions to observations.Results.First, we show that the asymptotic value ofεgwell agrees with the mean value observed at the beginning of the ascent of the red giant branch, which results from the high density contrast between the helium core and the base of the convective envelope. Second, we demonstrate that the predicted value also explains the sharp decrease inεgobserved for the more luminous red giant stars of the sample. This rapid drop turns out to occur just before the luminosity bump and results from the kink of the Brunt–Väisälä frequency near the upper turning point associated with the buoyancy cavity as stars evolve and this latter nears the base of the convective envelope. The potential ofεgto probe the value and slope of the Brunt–Väisälä frequency below the base of the convective region is clearly highlighted.Conclusions.The observed variation inεgand its link with the internal properties on the red giant branch are now globally understood. This work motivates further analyses of the potential of this parameter as a seismic diagnosis of the region located between the hydrogen-burning shell and the base of the convective envelope, and of the local dynamical processes associated for instance with core contraction, the migration of the convective boundary, or overshooting.

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Motamedi, Mahdi, Chia-Yang Chung, Mehdi Rafeie, Natasha Hjerrild, Fan Jiang, Haoran Qu, and Robert A. Taylor. "Experimental Testing of Hydrophobic Microchannels, with and without Nanofluids, for Solar PV/T Collectors." Energies 12, no. 15 (August 6, 2019): 3036. http://dx.doi.org/10.3390/en12153036.

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Solar energy can be converted into useful energy via photovoltaic cells or with a photothermal absorber. While these technologies are well-developed and commercially viable, significant benefits can be realised by pulling these two technologies together in photovoltaic/thermal (PV/T) systems which can provide both heat and electricity from a single collector. Emerging configurations in the PV/T field aim to incorporate micro and/or nanotechnology to boost total solar utilisation even further. One example of this is the nanofluid-based PV/T collector. This type of solar collector utilises nanofluids—suspensions of nanoparticles in traditional heat transfer fluids—as both an optical filter and as a thermal absorber. This concept seeks to harvest the whole solar spectrum at its highest thermodynamic potential through specially engineered nanofluids which transmit the portion of solar spectrum corresponding to the PV response curve while absorbing the rest as heat. Depending on the nanoparticle concentration, employing nanofluids in a flowing system may come with a price—an efficiency penalty in the form of increased pumping power (due to increased viscosity). Similarly, microchannel-based heat exchangers have been shown to increase heat transfer, but they may also pay the price of high pumping power due to additional wall-shear-related pressure drop (i.e., more no-slip boundary area). To develop a novel PV/T configuration which pulls together the advantages of these micro and nanotechnologies with minimal pumping power requirements, the present study experimentally investigated the use of nanofluids in patterned hydrophobic microchannels. It was found that slip with the walls reduced the impact of the increased viscosity of nanofluids by reducing the pressure drop on average 17% relative to a smooth channel. In addition, flowing a selective Ag/SiO2 core–shell nanofluid over a silicon surface (simulating a PV cell underneath the fluid) provided a 20% increase in solar thermal conversion efficiency and ~3% higher stagnation temperature than using pure water. This demonstrates the potential of this proposed system for extracting more useful energy from the same incident flux. Although no electrical energy was extracted from the underlying patterned silicon, this study highlights potential a new development path for micro and nanotechnology to be integrated into next-generation PV/T solar collectors.

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48

Chaurasia, Ankur S., and Shahriar Sajjadi. "Millimetric core–shell drops via buoyancy assisted non-confined microfluidics." Chemical Engineering Science 129 (June 2015): 260–70. http://dx.doi.org/10.1016/j.ces.2015.02.028.

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Arriaga, L. R., E. Amstad, and D. A. Weitz. "Scalable single-step microfluidic production of single-core double emulsions with ultra-thin shells." Lab on a Chip 15, no. 16 (2015): 3335–40. http://dx.doi.org/10.1039/c5lc00631g.

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50

Segall, Iris, Olga L. Shaffer, Victoria L. Dimonie, and Mohamed S. El-Aasser. "Morphological study of structured latex particles by Transmission Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 882–83. http://dx.doi.org/10.1017/s0424820100150241.

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Transmission electron microscopy plays an important role in the study of the influence polymerization conditions have on the morphology of structured latex particles and thus in the understanding of the morphological effect of such particles on the structure-property relationships of polymeric end products.Structured latex particles are prepared by seeded emulsion polymerization, where the first stage is a polymerization of ”the core” poly(n-butyl acrylate) (PBA), followed by a second stage polymerization of ”the shell” poly(benzyl methacrylate/styrene) (P(BM/St)) at various ratios. The changes in polymerization conditions include such variables as the polymerization mode (batch vs. semicontinuous), core/shell ratio, shell thickness, and shell composition. Morphology studies of the structured latex particles are performed by transmission electron microscopy on preferentially stained samples. In a small vial, a few drops of latex sample are combined with a few drops of uranyl acetate (UAc) 2% solution. The uranyl acetate serves as a negative staining to better delineate the particles edges.

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Journal articles on the topic 'Core-shell drop'

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