Dynamics of suspensions of hydrodynamically structured particles: Analytic theory and experiment

We present an easy-to-use analytic toolbox for the calculation of short-time transport properties of concentrated suspensions of spherical colloidal particles with internal hydrodynamic structure, and direct interactions described by a hard-core or soft Hertz pair potential. The considered dynamic properties include self-diffusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined in dynamic scattering experiments, and the high-frequency shear viscosity. The toolbox is based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on a hydrodynamic radius parameter for unchanged direct interactions, and on an existing simulation data base for solvent-permeable and spherical annulus particles. Useful scaling relations for the diffusion function and self-diffusion coefficient, known to be valid for hard-core interaction, are shown to apply also for soft pair potentials. We further discuss extensions of the toolbox to long-time transport properties including the low-shear zero-frequency viscosity and the long-time self-diffusion coefficient. The versatility of the toolbox is demonstrated by the analysis of a previous light scattering study of suspensions of non-ionic PNiPAM microgels [Eckert et al., J. Chem. Phys., 2008, 129, 124902] in which a detailed theoretical analysis of the dynamic data was left as an open task. By the comparison with Hertz potential based calculations, we show that the experimental data are consistently and accurately described using the Verlet-Weis corrected Percus-Yevick structure factor as input, and for a solvent penetration length equal to three percent of the excluded volume radius. This small solvent permeability of the microgel particles has a significant dynamic effect at larger concentrations.Comment: 25 pages, 24 figure

Anticipation in turn-taking: mechanisms and information sources

Riest C, Jorschick A, de Ruiter J. Anticipation in turn-taking: mechanisms and information sources. Frontiers in Psychology. 2015;6: 89.During conversations participants alternate smoothly between speaker and hearer roles with only brief pauses and overlaps. There are two competing types of accounts about how conversationalists accomplish this: (a) the signaling approach and (b) the anticipatory ('projection') approach. We wanted to investigate, first, the relative merits of these two accounts, and second, the relative contribution of semantic and syntactic information to the timing of next turn initiation. We performed three button-press experiments using turn fragments taken from natural conversations to address the following questions: (a) Is turn-taking predominantly based on anticipation or on reaction, and (b) what is the relative contribution of semantic and syntactic information to accurate turn-taking. In our first experiment we gradually manipulated the information available for anticipation of the turn end (providing information about the turn end in advance to completely removing linguistic information). The results of our first experiment show that the distribution of the participants' estimation of turn-endings for natural turns is very similar to the distribution for pure anticipation. We conclude that listeners are indeed able to anticipate a turn-end and that this strategy is predominantly used in turn-taking. In Experiment 2 we collected purely reacted responses. We used the distributions from Experiments 1 and 2 together to estimate a new dependent variable called Reaction Anticipation Proportion. We used this variable in our third experiment where we manipulated the presence vs. absence of semantic and syntactic information by low-pass filtering open-class and closed class words in the turn. The results suggest that for turn-end anticipation, both semantic and syntactic information are needed, but that the semantic information is a more important anticipation cue than syntactic information

Feasibility of utilizing wood debris for biofuels in Northwestern Ontario

In recent years’ production of transportation biofuels generated from forest residues have grown rapidly on a global scale. Converting to advanced biofuels is enticing because they can help reduce dependence on oil; mitigate global warming; free up agricultural land and utilize waste wood. To encourage advanced biofuel production, Canada can look to Countries like Sweden that provide subsidies for advanced biofuels. In this undergraduate thesis thermochemical conversion had the lowest average cost of production for all the studies that had techno-economic in the production of cellulosic ethanol at US$0.33/L

Status Terinfeksi Ektoparasit pada Kucing Kampung (Felis silvestris catus) Liar di Desa Waru Barat Kota Pamekasan

Ectoparasites are parasites that infest the body surface of cats. Ectoparasites interfere with the health of the main host, such as skin diseases, anemia, hypersensitivity disorders, dermatitis and as vectors of disease transmission. Ectoparasites are also zoonotic in which their effects cause harm to humans. Ectoparasites in cats can be transmitted to humans during cat-human interactions. Some of the ectoparasites that have symbiosis with cats are fleas, mites, ticks, and fleas. The purpose of this study was to determine the status of ectoparasite infection in feral cats in the Waru Barat area of Pamekasan City. This research is descriptive. The sampling method used accidental sampling with a sample of 18 wild cats (Felis silvestris catus) in Waru Barat Village, Pamekasan City. Based on the results of research on wild cats (Felis silvestris catus) in Waru Barat Village, Pamekasan City, it was concluded that as many as 18 samples (100%) were infected with ectoparasites. The type of ectoparasite that infects is the flea (Ctenocephalides felis)

Kontaminasi Kapang pada Ikan Pindang yang Dijual di Pasar Tradisional Mangga Dua Kota Surabaya

Ikan pindang umumnya mudah busuk dan rusak karena mempunyai kadar air yang relatif tinggi dan sesuai dengan pertumbuhan mikroorganisme, terutama bakteri pembentuk lendir dan kapang. Penelitian ini bertujuan untuk mengetahui kontaminasi kapang dan jenis kapang pada ikan pindang yang dijual di Pasar Mangga Dua Surabaya. Jenis penelitian adalah deskriptif. Populasi penelitian adalah ikan pindang yang dijual di Pasar Mangga Dua Surabaya. Total sampel keseluruhan sebanyak 30 ikan pindang. Pemeriksaan jenis kapang dilakukan dengan metode isolasi kapang dari sampel ikan pindang. Kemudian dilanjutkan mengkulturkan pada media SDA (Saboround Dextrose Agar) dan diinkubasi selama 5-7 hari pada suhu ruang. Hasil penelitian menunjukan bahwa 8 sampel (27%) terkontaminasi dan 22 sampel (73%) tidak tekontaminasi kapang. Pada ikan pindang ditemukan jenis kapang Aspergillus sp

Early preparation during turn-taking:Listeners use content predictions to determine <i>what</i> to say but not <i>when</i> to say it

During conversation, there is often little gap between interlocutors' utterances. In two pairs of experiments, we manipulated the content predictability of yes/no questions to investigate whether listeners achieve such coordination by (i) preparing a response as early as possible or (ii) predicting the end of the speaker's turn. To assess these two mechanisms, we varied the participants' task: They either pressed a button when they thought the question was about to end (Experiments 1a and 2a), or verbally answered the questions with either yes or no (Experiments 1b and 2b). Predictability effects were present when participants had to prepare a verbal response, but not when they had to predict the turn-end. These findings suggest content prediction facilitates turn-taking because it allows listeners to prepare their own response early, rather than because it helps them predict when the speaker will reach the end of their turn

Dynamics in colloid and protein systems: Hydrodynamically structured particles, and dispersions with competing attractive and repulsive interactions

In this thesis, we develop and apply a toolbox of versatile theoretical methods of calculating structural, and short-time and long-time dynamic properties of three classes of industrially important dispersions. The first one are suspensions of hydrodynamically structured colloidal particles, and here most notably non-ionic microgels. The second class are dispersions of submicron sized charge-stabilized colloidal globules, and the third one are globular protein solutions with competing short-range attraction (SA) and long-range repulsion (LR). The results for the transport, structure, and thermodynamic properties of charge-stabilized colloids are used as input in our realistic macroscopic diffusion-advection modeling of the membrane cross-flow ultrafiltration of silica particles dispersions. The thesis bridges thus the gap from the theoretical exploration of intra-particle properties such as solvent permeability, particle softness, and surface charge, to the calculation of transport, structural, and thermodynamic properties of concentrated dispersions, and to the modeling of a technologically important fltration process. The accuracy of our toolbox methods is assessed by the comprehensive comparison with experimental measurements of, and simulation results for static and dynamic properties. The considered dynamic properties include short- and long-time self-diusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined routinely in dynamic scattering experiments, and the zero- and high-frequency shear viscosities. In particular, we provide various analytic transport coefficient expressions for rigid permeable particles that can be readily used for the analysis of dynamic scattering and rheology data. The toolbox methods for the calculation of transport properties of concentrated dispersions of globular colloidal particles with internal hydrodynamic structure are based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on an effective hydrodynamic radius for unchanged direct interactions. The good performance of the HRM is demonstrated by comparison with dynamic light scattering experiments on concentrated suspensions of solvent permeable non-ionic microgels. Furthermore, we quantify the effect of particle softness and permeability on the dynamics of ionic microgel suspensions, and we characterize the particle interactions and microstructure inpolydisperse amphoteric microgel systems in the zwitterionic regime. [...