Two-Stage Stabiliser Addition Protocol as a Means to Reduce the Size and Improve the Uniformity of Polymer Beads in Suspension Polymerisation

A 2-stage stabiliser addition protocol is suggested for reducing the size and improving the uniformity of polymer beads resulting from conventional suspension polymerisation. The stabiliser load was divided into an initial charge and a secondary addition. The use of a low concentration of stabilizer in the initial charge served to assist drop rupture while avoiding significant reduction in drop size and production of too many satellite droplets. The secondary addition time of stabiliser occurred just before the onset of the growth stage when drops were vulnerable to coalescence but were robust against break up due to their high viscosity. The secondary addition of stabiliser served to provide stability to monomer drops during the growth stage and as a result the drops underwent limited coalescence. This resulted in the formation of smaller and more uniform polymer beads in comparison to beads obtained by conventional suspension polymerisation at the same overall concentration of stabiliser

Asymptotic Multi-Layer Analysis of Wind Over Unsteady Monochromatic Surface Waves

Asymptotic multi-layer analyses and computation of solutions for turbulent flows over steady and unsteady monochromatic surface wave are reviewed, in the limits of low turbulent stresses and small wave amplitude. The structure of the flow is defined in terms of asymptotically-matched thin-layers, namely the surface layer and a critical layer, whether it is elevated or immersed, corresponding to its location above or within the surface layer. The results particularly demonstrate the physical importance of the singular flow features and physical implications of the elevated critical layer in the limit of the unsteadiness tending to zero. These agree with the variational mathematical solution of Miles (1957) for small but finite growth rate, but they are not consistent physically or mathematically with his analysis in the limit of growth rate tending to zero. As this and other studies conclude, in the limit of zero growth rate the effect of the elevated critical layer is eliminated by finite turbulent diffusivity, so that the perturbed flow and the drag force are determined by the asymmetric or sheltering flow in the surface shear layer and its matched interaction with the upper region. But for groups of waves, in which the individual waves grow and decay, there is a net contribution of the elevated critical layer to the wave growth. Critical layers, whether elevated or immersed, affect this asymmetric sheltering mechanism, but in quite a different way to their effect on growing waves. These asymptotic multi-layer methods lead to physical insight and suggest approximate methods for analyzing higher amplitude and more complex flows, such as flow over wave groups.Comment: 20 page

“On-The-Fly” Fabrication of Highly-Ordered Interconnected Cylindrical and Spherical Porous Microparticles via Dual Polymerization Zone Microfluidics

A microfluidic platform with dual photopolymerization zones has been developed for production of novel uniform interconnected porous particles with shapes imposed either by the geometry of the external capillary or by the thermodynamic minimisation of interfacial area. Double w/o/w drops with well-defined internal droplet size and number were produced and then exposed to online photopolymerization to create the porous particles. Cylindrical interconnected porous particles were produced in a segmented flow where the drops took the shape of the capillary. The microfluidic set up included an extension capillary where the drops relaxed and conformed to their thermodynamically favoured morphology. Window opening of the particles occurred “on-the-fly” during UV polymerization without using any offline auxiliary methods. A distinction was made between critically and highly packed arrangements in double drops. The window opening occurred consistently for highly packed spherical drops, but only for critically packed drops containing more than 6 internal cores at internal phase ratio as low as 0.35. The size and number of cores, shape and structure of double drops could be precisely tuned by the flowrate and by packing structure of the inner droplets

Relative growth of the fiddler crab, Uca sindensis(Crustacea: Ocypodidae) in a subtropical mangrove in Pohl Port, Iran

The relative growth of the fiddler crab Uca sindensis in Pohl Port was studied. Ten 0.5 m^2 quadrates were randomly sampled monthly during low tide periods from October 2009 to September 2010. A total of 840 crabs, 449 (53.45%) males and 391 (46.5%) ‌ females, were sampled. The Carapace width of males ranged from 5.5 to 13.5 mm (mean ± SD) (8.92 ± 2.04), and of females from 5.0 to 11.5 mm (mean ± SD) (7.95 ± 1.34). Carapace height (CH) and Carapace length (CL), height of the major cheliped (HMC) of males, abdomen width of females (AW), major cheliped length (LMC), dactiluse (D), feeding cheliped (CHF) and merouse (M) were employed as dependent variables and carapace width (CW) as independent variable. The relationship between CW × CH was positive in males and females. The equation (Log CH=Log-4.881+4.681LogCW) for males (P<0.05) and Log CH=Log-1.882+3.299LogCW for females (P<0.05). The females showed allometric positive growth for CW × AW relation to male (Log AW= Log0.784+1.217Log CW) (P<0.05). Also four male crabs were found with two major cheliped in this study. Remarkable ontogenetic changes were observed in the allometric growth of the male major cheliped and the female abdomen, indicating that these structures are closely connected to the timing of sexual maturity. The allometric growth of U. sindensis in Pohl Port mangrove differed from other Uca populations so far studied, indicating that growth could have been influenced by environment variables such as food availability, population density, distribution of vegetation, sex ratio, soil temperature , organic matter, different of surface and sediment

Health system responsiveness for outpatient care in people with diabetes Mellitus in Tehran

Background: World Health Organization (WHO) defines three goals to assess the performance of a health system: the state of health, fairness in financial contribution and responsiveness. We assessed the responsiveness of health system for patients with diabetes in a defined population cohort in Tehran, Iran. Methods: Total responsiveness and eight domains (prompt attention, dignity, communication, autonomy, confidentiality, choice, basic amenities and discrimination) were assessed in 150 patients with diabetes as a representative sample from the Tehran Glucose and Lipid Study (TLGS) population cohort. We used the WHO questionnaire and methods for analysis of responsiveness. Results: With respect to outpatient services, 67 (n=100) were classified as Good for total responsiveness. The best and the worse performing results were related to information confidentiality (84 good responsiveness) and autonomy (51 good responsiveness), respectively. About 61 chose "communication" as the most important domain of responsiveness; it was on the 4th rank of performance. The proportions of poor responsiveness were higher in women, individuals with lower income, lower level of education, and longer history of diabetes. "Discrimination" was considered discrimination as the cause of inappropriate services by 15, and 29 had limited access to services because of financial unaffordability. Conclusion: Health system responsiveness is not appropriate for diabetic patients. Improvement of responsiveness needs comprehensive planning to improve attitudes of healthcare providers and system behavior. Activities should be prioritized through considering weaker domains of performance and more important domains from the patients' perspective

Preparation and characterization of tunable oil-encapsulated alginate microfibers

© 2017 Elsevier LtdA single-step microfluidic approach was developed which allowed a wide range of oil-loaded calcium-alginate microfibers to be fabricated at the same compositions but with different morphologies. A framework for characterization of wavy fibers was developed which linked the fiber morphology and tensile strength to the encapsulation type and geometry. The geometry of oil encapsulates as well as the fibers surface morphology were conveniently tuned via the gelation reaction dynamics and phase flow rates. A 2D mathematical reconstruction of the fiber's surface revealed that fibers having spherical and ellipsoid encapsulates enjoyed the highest surface roughness. Tubular fibers endured the highest tensile force before failure, compared to fibers with other encapsulate geometries at a fixed alginate phase ratio (ϕalg). Fibers with increased ϕalg withstood a higher tensile force. However, the strength of fibers reduced if the increase in ϕalg altered the encapsulate geometry from tubular to discrete oil segments. Tubular fibers also underwent maximum elastic and plastic deformation prior to failure, among all fibers

Digital turn and its implications on teacher’s professional achievement: learning communities formation among teachers

Nowadays, digital technology has reduced teachers’ professional isolation by facilitating communications and interactions. In the modern knowledge-based world, teachers as learners participate in professional learning communities to seek knowledge resources for more effective teaching and consequently the improvement of their students’ learning. In fact, professional learning communities are as context for teachers’ professional development. The goal of this research is discovering achievements that teachers achieve by participating in learning communities. Method of Research is the literature review.  Results show that teachers’ participation in learning communities leads to valuable achievements for them

Modified Heider Balance on Sparse Random Networks

The lack of signed random networks in standard balance studies has prompted us to extend the Hamiltonian of the standard balance model. Random networks with tunable parameters are suitable for better understanding the behavior of standard balance as an underlying dynamics. Moreover, the standard balance model in its original form does not allow preserving tensed triads in the network. Therefore, the thermal behavior of the balance model has been investigated on a fully connected signed network recently. It has been shown that the model undergoes an abrupt phase transition with temperature. Considering these two issues together, we examine the thermal behavior of the structural balance model defined on Erd\H{o}s-R\'enyi random networks. We provide a Mean-Field solution for the model. We observe a first-order phase transition with temperature, for both the sparse and densely connected networks. We detect two transition temperatures, $T_{cold}$ and $T_{hot}$, characterizing a hysteresis loop. We find that with increasing the network sparsity, both $T_{cold}$ and $T_{hot}$ decrease. But the slope of decreasing $T_{hot}$ with sparsity is larger than the slope of decreasing $T_{cold}$. Hence, the hysteresis region gets narrower, until, in a certain sparsity, it disappears. We provide a phase diagram in the temperature-tie density plane to observe the meta-stable/coexistence region behavior more accurately. Then we justify our Mean-Field results with a series of Monte-Carlo simulations.Comment: 10 Pages, 5 Figure