The Effect of Various Pigments and Binders on Coated Gloss, Print Gloss, and Delta Gloss

The objective of this thesis is to determine the effects that various pigments and binders have on the coated gloss, print gloss, and delta gloss values. The effects of coat weight and calendering on the glossing response of the sheet will also be determined. Supplemental tests such as Parker Print Surf Roughness, brightness, and opacity will be measured to further evaluate the coating formulations. A total eight different coating formulations were made using four very common pigments and two latex binders. The four pigments used were #2 clay (100%), calcined clay (15% substitution), delaminated clay (25% substitution), and calcium carbonate (100%). The two latex binders used were styrene butadiene (SBR) and polyvinyl acetate (PVAC). Latex binders were chosen because their gloss response when applied in coatings is better than starch or protein binders. In order to isolate the effect of the pigment and binders a number of variables were held constant or within the same range. The solids levels of all coatings was adjusted to 62%. The binder ratio used was 12% based on dry parts pigment. The Brookfield viscosity was adjusted within the same range using polyacrylate. The printing ink and the print conditions were held constant also. The ink used was a low viscosity water based flexographic ink. A low gloss ink was chosen in order to eliminate the effects of the ink on the print gloss. When pigments are used alone in coating formulations, their particle size has the most dramatic effect on the gloss response of the sheet. The finer particles create a more optically smooth sheet therefore giving higher gloss values. When binders are introduced into the sheet, the pigment to binder particle interaction also plays a major role. A coat weight increase of 5 g/m^2 gave an average increase in coated gloss of 10% and gave a 20% increase in calendered gloss. The delaminated clay using the PVAC as the binder showed the highest gloss response due to an increase in coat weight. Calendering the sheet improved all gloss values. The effect was greater for coated gloss than for the print gloss. This was desired because it proves that the gloss of ink did not contribute to the print gloss but that it was the coating structure that affected the gloss response. The effect of pigment and binder type varied depending upon the combination used. The calcined clay gave the highest calendered gloss values which was not expected. However, when these samples were printed they displayed the highest delta gloss. This is due to the large particle size of the calcined clay. High delta gloss values are not desired because they produce a contrast between the image of the coating and the printed image. The pigment-binder interaction played a major role in determining the gloss response. When the PVAC binder was used, the delaminated clay gave the best gloss response with a delta gloss value of near zero (.2). When the SBR was used, the #2 clay gave the best response in gloss response. This was expected because the SBR latex is known for its high gloss response. A more detailed description and interpretation of the results can be found in the results and discussion section

Simulation and assimilation of satellite altimeter data at the oceanic mesoscale

An improved "objective analysis' technique is used along with an altimeter signal statistical model, an altimeter noise statistical model, an orbital model, and synoptic surface current maps in the POLYMODE-SDE area, to evaluate the performance of various observational strategies in catching the mesoscale variability at mid-latitudes. In particular, simulated repetitive nominal orbits of ERS-1, TOPEX, and SPOT/POSEIDON are examined. Results show the critical importance of existence of a subcycle, scanning in either direction. Moreover, long repeat cycles ( 20 days) and short cross-track distances ( 300 km) seem preferable, since they match mesoscale statistics. Another goal of the study is to prepare and discuss sea-surface height (SSH) assimilation in quasigeostrophic models. Restored SSH maps are shown to meet that purpose, if an efficient extrapolation method or deep in-situ data (floats) are used on the vertical to start and update the model

Avaliação da resistência de união à microtração da resina composta pré-aquecida na cimentação de onlays de diferentes espessuras

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.A cimentação é considerada o procedimento mais crítico das restaurações indiretas e o cimento utilizado é considerado o elo mais fraco da estrutura formada pela associação peça protética-cimento-dente. O objetivo deste trabalho foi avaliar a resistência de união a microtração promovida pela resina composta pré-aquecida, utilizada para cimentação de restaurações indiretas de diferentes espessuras. Foram selecionados 32 incisivos bovinos hígidos padronizados com 12mm de comprimento e com a exposição da dentina coronária. Os dentes foram divididos em 4 grupos (n=8), de acordo com a espessura do bloco de resina composta e o cimento utilizado: grupos 1 e 2 (RC2, RC4) – blocos de resina composta de 2mm e 4mm de espessura e cimentação com resina composta pré-aquecida; grupos 3 e 4 (CR2, CR4) – blocos de resina composta de 2mm e 4mm e cimentação com cimento resinoso dual. Previamente a cimentação, os blocos foram jateados com óxido de alumínio, condicionados com ácido fosfórico a 37% e o sistema adesivo foi aplicado sem fotoativação. Os dentes bovinos foram jateados, condicionados e tiveram o adesivo fotoativado por 40s. A cimentação foi realizada com resina composta pré-aquecida para os grupos 1 e 2, e cimento resinoso dual para os grupos 3 e 4, com o auxílio de uma barreira de silicone, afim de permitir que a luz do fotopolimerizador haja somente na superfície oclusal do bloco. Os espécimes ficaram em um ambiente úmido e escuro durante 30 dias para aguardar a polimerização total do material para cimentação. Após 30 dias, os espécimes foram seccionados para obtenção de palitos de 1mm2, que foram submetidos ao teste de microtração. Os resultados mostraram que não houve diferenças estatísticas entre a resistência de união à microtração nos grupos RC2 e RC4 (p>0,05), bem como entre os grupos CR2 e CR4 (p>0,05). Entretanto, houve diferenças estatisticamente significativas entre CR2 e RC4 (p<0,05). Concluiu-se que a resina composta pré-aquecida como agente cimentante é tão efetiva quanto o cimento resinoso independente da espessura da restauração indireta utilizada (até 4 mm)

Access to Political Rights in Switzerland: Critique of the Naturalisation Process as a Source of Exclusion

In this article, we analyse and discuss the legal criteria granting access to facilitated naturalisation in Switzer- land. Among the possible legal criteria, marriage to a Swiss citizen as a criterion for obtaining citizenship is em- blematic of the conservative political background in this country. It is also influenced by gendered stereotypes within the law itself and its application. We argue in fa- vour of a critical approach to the law in order to avoid the erasure of categories of individuals who are relegated to society’s margins. In a healthy democracy and judicial system, the law ought to be designed so as to avoid repro- ducing exclusionary bias. In this regard, we also discuss why acceding to citizenship is a prerequisite for exercis- ing one’s political rights and thus, achieving inclusion in Switzerland

An Overview of Molten Polymer Drawing Instabilities

International audienceDrawing instabilities and rupture are a serious limitation in polymer fibre and film processing. Draw resonance and fibre or film rupture depend on the processing conditions, heat transfer and on the rheology of the polymer and some of these defects may also be encountered for Newtonian fluids. This paper reviews the different instabilities observed in fibre spinning, cast-film and film blowing. The time dependent equations are presented for the simplified situation of constant width cast-film and two modelling strategies, linear stability analysis and direct simulation, are proposed and then applied to the different fibre and film processes. Read More: http://www.hanser-elibrary.com/doi/abs/10.3139/217.283

Controlling the stability transfer between oppositely traveling waves and standing waves by inversion-symmetry-breaking perturbations

The effect of an externally applied flow on symmetry degenerated waves propagating into opposite directions and standing waves that exchange stability with the traveling waves via mixed states is analyzed. Wave structures that consist of spiral vortices in the counter rotating Taylor-Couette system are investigated by full numerical simulations and explained quantitatively by amplitude equations containing quintic coupling terms. The latter are appropriate to describe the influence of inversion symmetry breaking perturbations on many oscillatory instabilities with O(2) symmetry.Comment: 4 pages, 4 figure