scholarly journals Production of monodisperse polyurea microcapsules using microfluidics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael F. Thorne ◽  
Felix Simkovic ◽  
Anna G. Slater
Keyword(s):  
Video Recording ◽  
Size Control ◽  
Size Distributions ◽  
Energy Applications ◽  
Automated Method ◽  
Commercial Glass ◽  
Glass Chip ◽  
Effect Of Particle Size ◽  
Size Controlled ◽  
Capsule Size

AbstractMethods to make microcapsules – used in a broad range of healthcare and energy applications – currently suffer from poor size control, limiting the establishment of size/property relationships. Here, we use microfluidics to produce monodisperse polyurea microcapsules (PUMC) with a limonene core. Using varied flow rates and a commercial glass chip, we produce capsules with mean diameters of 27, 30, 32, 34, and 35 µm, achieving narrow capsule size distributions of ±2 µm for each size. We describe an automated method of sizing droplets as they are produced using video recording and custom Python code. The sustainable generation of such size-controlled PUMCs, potential replacements for commercial encapsulated systems, will allow new insights into the effect of particle size on performance.

scholarly journals FaceSync: Open source framework for recording facial expressions with head-mounted cameras

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 702 ◽  
Author(s):  
Jin Hyun Cheong ◽  
Sawyer Brooks ◽  
Luke J. Chang
Keyword(s):  
Facial Expression ◽  
Open Source ◽  
Facial Expressions ◽  
Video Recording ◽  
Machine Learning Algorithms ◽  
Expression Data ◽  
Video Recordings ◽  
Automated Method ◽  
Open Source Framework ◽  
The Cost

Advances in computer vision and machine learning algorithms have enabled researchers to extract facial expression data from face video recordings with greater ease and speed than standard manual coding methods, which has led to a dramatic increase in the pace of facial expression research. However, there are many limitations in recording facial expressions in laboratory settings.  Conventional video recording setups using webcams, tripod-mounted cameras, or pan-tilt-zoom cameras require making compromises between cost, reliability, and flexibility. As an alternative, we propose the use of a mobile head-mounted camera that can be easily constructed from our open-source instructions and blueprints at a fraction of the cost of conventional setups. The head-mounted camera framework is supported by the open source Python toolbox FaceSync, which provides an automated method for synchronizing videos. We provide four proof-of-concept studies demonstrating the benefits of this recording system in reliably measuring and analyzing facial expressions in diverse experimental setups, including group interaction experiments.

scholarly journals Size-Controlled Synthesis of CoFe2O4Nanoparticles Potential Contrast Agent for MRI and Investigation on Their Size-Dependent Magnetic Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Fujun Liu ◽  
Sophie Laurent ◽  
Alain Roch ◽  
Luce Vander Elst ◽  
Robert N. Muller
Keyword(s):  
Magnetic Layer ◽  
Size Control ◽  
Correlation Spectroscopy ◽  
Local Concentration ◽  
Long Term Stability ◽  
Size Dependent ◽  
Transmission Electron ◽  
Size Controlled ◽  
Size Of Nuclei

Cobalt ferrite nanoparticles (CoFe2O4NPs) were synthesized by coprecipitation followed by treatments with diluted nitric acid and sodium citrate. Transmission electron microscope (TEM) and photon correlation spectroscopy (PCS) characterization showed that the size distributions of these nanoparticles were monodisperse and that no aggregation occurred. This colloid showed a long-term stability. Through adjustment of the concentrations of reactants and reaction temperature, the size of the NPs can be tuned from 6 to 80 nm. The size-control mechanism is explained by a nucleation-growth model, where the local concentration of monomers is assumed to decide the size of nuclei, and reaction temperatures influence the growth of nuclei. Magnetization and relaxivityr1,2measurements showed that the NPs revealed size-dependent magnetization and relaxivity properties, which are explained via a “dead magnetic layer” theory where reductions of saturation magnetization (Ms) andr1,2are assumed to be caused by the demagnetization of surface spins.

scholarly journals Size-controlled and water-soluble gold nanoparticles using UV-induced ligand exchange and phase transfer

2018 ◽  
Vol 54 (95) ◽  
pp. 13355-13358 ◽  
Author(s):  
Jan Bart ten Hove ◽  
Laura M. I. Schijven ◽  
Junyou Wang ◽  
Aldrik H. Velders
Keyword(s):  
Gold Nanoparticles ◽  
Ligand Exchange ◽  
Water Solubility ◽  
Phase Transfer ◽  
Water Soluble ◽  
Size Distributions ◽  
Seeded Growth ◽  
Growth Approach ◽  
Size Controlled

Oleylamine-capped gold nanoparticles (AuNPs) with sizes ranging from 5 to 13 nm and narrow size distributions (<10%) are synthesized by using a seeded growth approach. Water-solubility is achieved by using a UV-induced ligand exchange approach.

A new gradient based step size controlled inverse eigen sensitivity algorithm for identification of material and boundary parameters of plates

2015 ◽  
Vol 23 (16) ◽  
pp. 2619-2634
Author(s):  
Sk Abdul Goni ◽  
Subhajit Mondal ◽  
Sushanta Chakraborty
Keyword(s):  
Objective Function ◽  
Material Properties ◽  
Size Control ◽  
Initial Guess ◽  
Mode Shapes ◽  
Orthotropic Plates ◽  
Step Size ◽  
Step Size Control ◽  
Gradient Based ◽  
Size Controlled

The dynamic performance of any structure is function of existing material properties and boundary stiffness parameters which may deteriorate or become more flexible due to prolonged use. These parameters are estimated inversely through optimization of a suitable objective function. The gradient based optimization methods are preferred due to their faster convergence from a set of initial guess points, but suffers mostly from lack of reliable methodology to select appropriate step sizes. Arbitrary selection of step sizes may sometimes work well, depending upon the judgment of the user, but is case specific. The present work describes the estimation of existing material properties and boundary stiffness of isotropic and orthotropic plates from measured frequencies and mode shapes using a new gradient based step size controlled inverse eigensensitivity algorithm. The method takes a strategy that the step sizes automatically become smaller when the change in gradient of objective function is having a high value and similarly, takes larger steps when the gradient is remaining fairly constants in subsequent iterations. The results obtained from the investigations are encouraging, as some convergences could be achieved by this new adaptive step size control only, whereas methods adopting arbitrary or no step size control diverged.

scholarly journals A High-Yield Synthesis of Chalcopyrite CuInS2Nanoparticles with Exceptional Size Control

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Chivin Sun ◽  
Joseph S. Gardner ◽  
Endrit Shurdha ◽  
Kelsey R. Margulieux ◽  
Richard D. Westover ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Size Control ◽  
High Yield ◽  
Single Source ◽  
Icp Oes ◽  
Single Source Precursors ◽  
H Nmr ◽  
High Yields ◽  
Size Controlled

We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100°C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100°C to 200°C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by1H NMR using SSP1with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of Chalcopyrite CuInS2nanoparticles.

Effect of particle size distributions of activated sludges on cross-flow microfiltration flux for submerged membranes

1997 ◽  
Vol 83 (6) ◽  
pp. 583-589 ◽  
Author(s):  
Yasutoshi Shimizu ◽  
Katsushi Uryu ◽  
Yu-Ichi Okuno ◽  
Sadami Ohtubo ◽  
Atsuo Watanabe
Keyword(s):  
Particle Size ◽  
Cross Flow ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Effect Of Particle Size

scholarly journals Size-Control by Anion Templating in Mechanochemical Synthesis of Hemicucurbiturils in the Solid State

2018 ◽  
Author(s):  
Sandra Kaabel ◽  
Robin Stein ◽  
Maria Fomitšenko ◽  
Ivar Järving ◽  
Tomislav Friscic ◽  
...  
Keyword(s):  
Solid State ◽  
Self Assembly ◽  
Size Control ◽  
Solvent Free ◽  
Selective Assembly ◽  
Free System ◽  
Quantitative Synthesis ◽  
Solvent Free System ◽  
Acid Catalyzed ◽  
Size Controlled

Self-organization is one of the most intriguing phenomena of chemical matter. While the self-assembly of macrocycles and cages in dilute solution has been extensively studied, it remains poorly understood in solvent-free environments. Here, we provide the first example of using anionic templates to achieve selective assembly of differently sized macrocycles in a solvent-free system. Using the acid-catalyzed synthesis of cyclohexanohemicucurbiturils as a model system, we demonstrate size-controlled quantitative synthesis of 6- or 8-membered macrocycles, taking place through spontaneous anion-directed re-organization of mechanochemically-obtained oligomers in the solid state.<br>

scholarly journals Characterizing non-exponential growth and bimodal cell size distributions in Schizosaccharomyces pombe: an analytical approach

2021 ◽  
Author(s):  
Chen Jia ◽  
Abhyudai Singh ◽  
Ramon Grima
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Cell Size ◽  
Control Strategy ◽  
Size Control ◽  
Birth Size ◽  
Size Distributions ◽  
Cell Size Distribution ◽  
A Cell ◽  
Cell Size Control

Unlike many single-celled organisms, the growth of fission yeast cells within a cell cycle is not exponential. It is rather characterized by three distinct phases (elongation, septation and fission), each with a different growth rate. Experiments also show that the distribution of cell size in a lineage is often bimodal, unlike the unimodal distributions measured for the bacterium Escherichia coli. Here we construct a detailed stochastic model of cell size dynamics in fission yeast. The theory leads to analytic expressions for the cell size and the birth size distributions, and explains the origin of bimodality seen in experiments. In particular our theory shows that the left peak in the bimodal distribution is associated with cells in the elongation phase while the right peak is due to cells in the septation and fission phases. We show that the size control strategy, the variability in the added size during a cell cycle and the fraction of time spent in each of the three cell growth phases have a strong bearing on the shape of the cell size distribution. Furthermore we infer all the parameters of our model by matching the theoretical cell size and birth size distributions to those from experimental single cell time-course data for seven different growth conditions. Our method provides a much more accurate means of determining the cell size control strategy (timer, adder or sizer) than the standard method based on the slope of the best linear fit between the birth and division sizes. We also show that the variability in added size and the strength of cell size control of fission yeast depend weakly on the temperature but strongly on the culture medium.

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