Co-axial capillaries microfluidic device for synthesizing size- and morphology-controlled polymer core-polymer shell particles

An easy assembling-disassembling co-axial capillaries microfluidic device was built up for the production of double droplets. Uniform polymer core-polymer shell particles were synthesized by polymerizing the two immiscible monomer phases composing the double droplet. Thus poly(acrylamide) core-poly(tripropylenglycol-diacrylate) shell particles with controlled core diameter and shell thickness were simply obtained by adjusting operating parameters. An empirical law was extracted from experiments to predict core and shell sizes. Additionally uniform and predictable non-spherical polymer objects were also prepared without adding shape-formation procedures in the experimental device. An empirical equation for describing the lengths of rod-like polymer particles is also presented

Microfluidic-Assisted Synthesis of Polymer Particles

Microfluidic devices have recently emerged as promising tools for the synthesis of polymer particles. Over conventional processes, microfluidic-assisted processes allow the production of polymer particles with an improved control over their sizes, size distributions, morphologies, and compositions. In this paper, the most common microfluidic devices are reviewed. Both projection photolithography and emulsification processes are reported for the continuous flow synthesis of polymer particles from a stream of polymerizable liquids. For the latter process, two distinct categories of microfluidic devices have been identified: microchannel- based and capillary-based microsystems. For each category, the existing geometries are described and the different emulsification methods including the coflowing, cross-flowing, or flow-focusing of the continuous and dispersed phases are commented upon. Finally, for each microsystem the various polymer particles achieved in such devices including, but not restricted to, janus, core–shell, or porous particles and capsules are reported

Design and fabrication of 125I seeds for brachytherapy using capillary-based microfluidic technique

A new kind of 125I seeds with a core-shell structure were synthesized by an easy assembling–disassembling coaxial capillaries microfluidic device. The dose distribution of a 125I brachytherapy source fabricated by arranging six 125I seeds collinearly within a cylindrical titanium capsule was simulated by modelling the source in a water phantom using Monte Carlo N-Particle Transport code. The infl uence of the motion and the core size of the 125I seeds on the dose distribution was also studied in this work

Promotional versus (un) usual prices : evidence from Singapore

Our study investigates deceptive pricing practices in the retail market in Singapore through the conduct of a survey and collection of data from a range of physical and online retailers. About 336 Singaporeans were surveyed to analyze perceptions on misrepresentations in prices specific to luxury items which includes fragrances, bags and watches. A significant proportion of respondents displayed little awareness of the Consumer Protection (Fair Trading) Act. Several interesting findings were also made based on the three types of pricing distortions that we focus on i.e. RRP, UP and DP Distortions. Our regression analysis for RRP Distortion revealed varying degrees of distortive pricing with factors such as frequency of purchase, type of retailer, gender, brand and retailer popularity. UP and DP Distortions were also found to be present in the pricing strategies of retailers across all 3 product categories, albeit less frequently.Bachelor of Art

What are the impacts of Spartina alterniflora invasion on intertidal macrobenthic communities? A global meta-analysis

There is currently no consistent conclusion about the impacts of global Spartina alterniflora invasion on intertidal macrobenthic communities, and the impact mechanisms are also not clear enough due to the limitations in study sites and duration. Here, after collecting and extracting 2110 data from 96 studies around the world, we utilized hierarchical meta-analysis to quantify the impacts of Spartina alterniflora invasion on intertidal macrobenthic communities, and systematically analyzed and summarized the factors influencing invasion results for the first time. The results showed that the invasion of Spartina alterniflora generally has a negative impact on macrobenthic communities, but has a positive impact on species number and richness index of microbenthic communities. The pattern of influence strongly depends on the native habitat, invasion duration, average annual temperature, sediment type and tide level, which indicates that Spartina alterniflora affects macrobenthic communities by altering the external environment of the invaded area, and the habitat heterogeneity in different intertidal zones also leads to diverse impacts of Spartina alterniflora invasion on macrobenthic communities. Our study provides important insights for a comprehensive understanding of biological invasions and offers new perspectives for future ecological restoration in intertidal zones

What are the impacts of Spartina alterniflora invasion on intertidal macrobenthic communities? A global meta-analysis

There is currently no consistent conclusion about the impacts of global Spartina alterniflora invasion on intertidal macrobenthic communities, and the impact mechanisms are also not clear enough due to the limitations in study sites and duration. Here, after collecting and extracting 2110 data from 96 studies around the world, we utilized hierarchical meta-analysis to quantify the impacts of Spartina alterniflora invasion on intertidal macrobenthic communities, and systematically analyzed and summarized the factors influencing invasion results for the first time. The results showed that the invasion of Spartina alterniflora generally has a negative impact on macrobenthic communities, but has a positive impact on species number and richness index of microbenthic communities. The pattern of influence strongly depends on the native habitat, invasion duration, average annual temperature, sediment type and tide level, which indicates that Spartina alterniflora affects macrobenthic communities by altering the external environment of the invaded area, and the habitat heterogeneity in different intertidal zones also leads to diverse impacts of Spartina alterniflora invasion on macrobenthic communities. Our study provides important insights for a comprehensive understanding of biological invasions and offers new perspectives for future ecological restoration in intertidal zones

The Influence of Pore Distribution of Coal Char in the Char Fragmentation and Included Minerals Partitioning: A Percolation Modeling

The processes of char fragmentation, including mineral partitioning and particulate matter (PM) formation during dense and porous char combustion, were observed by a site percolation model. This model simulated the diffusion-controlled regime of char combustion, and the size distributions of included minerals in typical bituminous coal were determined by the computer-controlled scanning electron microscope (CCSEM), and the data were put into the char matrix randomly. The model presents the influence of initial pore distribution on char oxidation and fragmentation, the impact of the char conversion process on the extent of fragmentation, the change of ash distributions with the char conversion, and the particulate matters (PM) size distribution, which is derived from the consequence of the competition between char fragmentation and included minerals partitioning and coalescence. The results indicate that with increasing initial char porosity (φ), the number of large size pores increases but the number of pores decreases, which leads to open pores increasing, close pores decreasing, and the surface reaction area increasing. While φ ≥ 0.4, char fragmentation obviously occurs during the stage in which the rates of char conversion are 0.4–0.6, and it looks as though the maximum value of fragmentation will transfer to an earlier conversion stage if it has a larger φ. The enhanced φ shows a positive effect on the increase in the number and concentration of PM < 10 μm (nominally aerodynamic diameter), this is attributed to char fragments more drastically, and the probability of mineral coalescence reduces a lot

Fabrication of size-controlled CeO2 microparticles by a microfluidic sol–gel process as an analog preparation of ceramic nuclear fuel particles

Microfluidics integrated with sol-gel processes is introduced in preparing monodispersed MOX nuclear fuel microspheres using nonactive cerium as a surrogate for uranium or plutonium. The detailed information about microfluidic devices and sol-gel processes are provided. The effects of viscosity and flow rate of continuous and dispersed phase on size and size distribution of CeO2 microspheres have been investigated. A comprehensive characterization of the CeO2 microspheres has been conducted, including XRD pattern, SEM, density, size and size distribution. The size of prepared monodisperse particles can be controlled precisely in range of 10μm to 1000μm and the particle CV is below 3%