<p>This thesis considers the effect of manufacturing conditions and polymer ratio on water permeability and morphology of free-films. A novel spray method for producing ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) free-films was developed where several process parameters was controlled. The process was optimised by pre-spraying solvent until the system reached a steady-state temperature. This minimised the variation of outlet air temperature to < 2.5 °C. Coating time was approximately 4 minutes excluding drying.</p><p>Free-films were produced using 94 wt% solvent (95 %-ethanol) and 6 wt% polymer. The amount of HPC in the films was varied (wt% HPC defined as HPC/(HPC+EC)*100). Films with 30-40-50-57 wt% HPC were studied. Phase diagrams was constructed to study the phase transformation of polymer mixtures. Results show that all polymer mixtures with HPC content above 30 wt% were phase separated prior to film manufacturing. Temperature had an effect on the polymer phase transformation. In the phase diagram, the 2-phase area was larger for temperatures above 40 °C.</p><p>The investigated manufacturing conditions were outlet air temperature (°C) and spray rate (g/min). Outlet air temperature was controlled by adjusting the inlet air temperature. The films were characterized by measuring water permeability (m²/s). Cross section structure of the films was analyzed with confocal laser scanning microscopy (CLSM). FITC-HPC was added for enhanced contrast between the domains.</p><p>Higher outlet air temperature gave higher water permeability of the film whereas higher spray rate gave lower water permeability. The outlet air temperature had an impact on evaporation rate. The evaporation rate together with spray rate affected the solidification and hence the structure of the film. Images show that longer solidification time smeared the domains into larger domains. Lower water permeability was caused by less connectivity between the pores.</p><p>In conclusion, experiments show that water permeability of EC/HPC free-films was highly dependent on the manufacturing conditions.</p><p></p>

This thesis considers the effect of manufacturing conditions and polymer ratio on water permeability and morphology of free-films. A novel spray method for producing ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) free-films was developed where several process parameters was controlled. The process was optimised by pre-spraying solvent until the system reached a steady-state temperature. This minimised the variation of outlet air temperature to &lt; 2.5 °C. Coating time was approximately 4 minutes excluding drying. Free-films were produced using 94 wt% solvent (95 %-ethanol) and 6 wt% polymer. The amount of HPC in the films was varied (wt% HPC defined as HPC/(HPC+EC)*100). Films with 30-40-50-57 wt% HPC were studied. Phase diagrams was constructed to study the phase transformation of polymer mixtures. Results show that all polymer mixtures with HPC content above 30 wt% were phase separated prior to film manufacturing. Temperature had an effect on the polymer phase transformation. In the phase diagram, the 2-phase area was larger for temperatures above 40 °C. The investigated manufacturing conditions were outlet air temperature (°C) and spray rate (g/min). Outlet air temperature was controlled by adjusting the inlet air temperature. The films were characterized by measuring water permeability (m2/s). Cross section structure of the films was analyzed with confocal laser scanning microscopy (CLSM). FITC-HPC was added for enhanced contrast between the domains. Higher outlet air temperature gave higher water permeability of the film whereas higher spray rate gave lower water permeability. The outlet air temperature had an impact on evaporation rate. The evaporation rate together with spray rate affected the solidification and hence the structure of the film. Images show that longer solidification time smeared the domains into larger domains. Lower water permeability was caused by less connectivity between the pores. In conclusion, experiments show that water permeability of EC/HPC free-films was highly dependent on the manufacturing conditions.

abstract: Nanoporous materials, with pore sizes less than one nanometer, have been incorporated as filler materials into state-of-the-art polyamide-based thin-film composite membranes to create thin-film nanocomposite (TFN) membranes for reverse osmosis (RO) desalination. However, these TFN membranes have inconsistent changes in desalination performance as a result of filler incorporation. The nano-sized filler’s transport role for enhancing water permeability is unknown: specifically, there is debate around the individual transport contributions of the polymer, nanoporous particle, and polymer/particle interface. Limited studies exist on the pressure-driven water transport mechanism through nanoporous single-crystal nanoparticles. An understanding of the nanoporous particles water transport role in TFN membranes will provide a better physical insight on the improvement of desalination membranes. This dissertation investigates water permeation through single-crystal molecular sieve zeolite A particles in TFN membranes in four steps. First, the meta-analysis of nanoporous materials (e.g., zeolites, MOFs, and graphene-based materials) in TFN membranes demonstrated non-uniform water-salt permselectivity performance changes with nanoporous fillers. Second, a systematic study was performed investigating different sizes of non-porous (pore-closed) and nanoporous (pore-opened) zeolite particles incorporated into conventionally polymerized TFN membranes; however, the challenges of particle aggregation, non-uniform particle dispersion, and possible particle leaching from the membranes limit analysis. Third, to limit aggregation and improve dispersion on the membrane, a TFN-model membrane synthesis recipe was developed that immobilized the nanoparticles onto the support membranes surface before the polymerization reaction. Fourth, to quantify the possible water transport pathways in these membranes, two different resistance models were employed. The experimental results show that both TFN and TFN-model membranes with pore-opened particles have higher water permeance compared to those with pore-closed particles. Further analysis using the resistance in parallel and hybrid models yields that water permeability through the zeolite pores is smaller than that of the particle/polymer interface and higher than the water permeability of the pure polymer. Thus, nanoporous particles increase water permeability in TFN membranes primarily through increased water transport at particle/polymer interface. Because solute rejection is not significantly altered in our TFN and TFN-model systems, the results reveal that local changes in the polymer region at the polymer/particle interface yield high water permeability. / Dissertation/Thesis / Doctoral Dissertation Chemical Engineering 2018

Im Rahmen der Dissertation wurde untersucht, wie die Wasserdurchlässigkeit von ToB unter Baustellenbedingungen geprüft werden kann und welcher Zusammenhang zwischen Verformungsmodul und Wasserdurchlässigkeit besteht und ob diese Eigenschaften baustofftech-nisch oder bautechnologisch beeinflussbar sind. Dazu wurden bei einer Vielzahl von Baumaßnahmen beim Ausbau des Autobahnnetzes in den neuen Bundesländern baubegleitende Messungen auf Tragschichten durchgeführt. Außerdem wurden auf verschiedenen ToB-Versuchsfeldern in einem Lysimeter Vergleichsuntersuchungen mit den Prüfgeräten Tropf-, Doppelring- und Standrohr-Infiltrometer durchgeführt. Außerdem fanden Untersuchungen auf zwei Versuchs-Baustraßen in Schotterwerken statt. Untersucht wurde zunächst, wie sich die Variation der Parameter Korngrößenverteilung, Kornform und Sandtyp sowie Verdich-tungswassergehalt und Verdichtungsgrad auf die Eigenschaften der ToB im Neuzustand auswirken. Es wurde außerdem Untersucht, inwieweit sich ein Zusammenhang darstellen lässt zwischen dem Anstieg der Tragfähigkeit (Ev2-Wert) über eine bestimmte Schichtdicke der ToB und ihrer Wasserdurchlässigkeit.

Yes / The water permeability constant, (Kw) is one of many important parameters that affect optimal design and operation of RO processes. In model based studies, e.g.within the RO process model, estimation of Kw is therefore important. There are only two available literature correlations for calculating the dynamic Kw values. However, each of them are only applicable for a given membrane type, given feed salinity over a certain operating pressure range. In this work, we develop a time dependent neural network (NN) based correlation to predict Kw in RO desalination processes under fouling conditions. It is found that the NN based correlation can predict the Kw values very closely to those obtained by the existing correlations for the same membrane type, operating pressure range and feed salinity. However, the novel feature of this correlation is that it is able to predict Kw values for any of the two membrane types and for any operating pressure and any feed salinity within a wide range. In addition, for the first time the effect of feed salinity on Kw values at low pressure operation is reported. While developing the correlation, the effect of numbers of hidden layers and neurons in each layer and the transfer functions is also investigated.

No description available.

My work describes technology design of pervious concrete. The theoretical part contains a research about this kind of concrete usually from foreign authors. In general, I focused on the composition of the PC, aggregate grading curve, behaviour of concrete in fresh state, storing and compaction of concrete. A critical part is the aggregate grading curve – it plays the main role in the final level of water permeability. Further, we will go through the real world scenarios where we can use this type of concrete and also through the associated drawbacks. A substantial part of this work is about development of water-permeability test. The practical part shows variety of recipes with a list of measured and observed characteristics (compressive strength, frost resistence and water-permeability). The conclusion includes evaluation of the results and suggestions for future development in this area.

Im Rahmen der Dissertation wurde untersucht, wie die Wasserdurchlässigkeit von ToB unter Baustellenbedingungen geprüft werden kann und welcher Zusammenhang zwischen Verformungsmodul und Wasserdurchlässigkeit besteht und ob diese Eigenschaften baustofftech-nisch oder bautechnologisch beeinflussbar sind. Dazu wurden bei einer Vielzahl von Baumaßnahmen beim Ausbau des Autobahnnetzes in den neuen Bundesländern baubegleitende Messungen auf Tragschichten durchgeführt. Außerdem wurden auf verschiedenen ToB-Versuchsfeldern in einem Lysimeter Vergleichsuntersuchungen mit den Prüfgeräten Tropf-, Doppelring- und Standrohr-Infiltrometer durchgeführt. Außerdem fanden Untersuchungen auf zwei Versuchs-Baustraßen in Schotterwerken statt. Untersucht wurde zunächst, wie sich die Variation der Parameter Korngrößenverteilung, Kornform und Sandtyp sowie Verdich-tungswassergehalt und Verdichtungsgrad auf die Eigenschaften der ToB im Neuzustand auswirken. Es wurde außerdem Untersucht, inwieweit sich ein Zusammenhang darstellen lässt zwischen dem Anstieg der Tragfähigkeit (Ev2-Wert) über eine bestimmte Schichtdicke der ToB und ihrer Wasserdurchlässigkeit.

No description available.

Um filme polimérico utilizado na fabricação de curativos adesivos não perfurados deve ter baixo módulo de elasticidade e boa permeabilidade ao vapor d\' água. O baixo módulo de elasticidade garante sensação de maior conforto do produto em contato com a pele quando a pessoa que o está utilizando movimenta a parte do corpo sobre a qual está aplicado o curativo, principalmente a região das articulações, como joelhos e cotovelos. A importância de uma boa permeabilidade ao vapor d\' água está relacionada, principalmente em curativos não perfurados, ao fato de que a pele perde água constantemente e, se o filme polimérico não permitir a saída dessa água ao meio ambiente, ocorrerá um fenômeno denominado maceração, que é a sensibilização excessiva da pele, causada pela hiper hidratação da mesma. O presente trabalho apresenta um estudo da permeabilidade ao vapor d\' água, bem como a caracterização vibracional e térmica de um filme polimérico constituído por três polímeros diferentes, desenvolvido para substituir a poliuretana utilizada atualmente na produção de curativos adesivos não perfurados, com custo inferior. Os polímeros que constituem o filme foram caracterizados separadamente e alguns resultados obtidos, como Tm e a estrutura química dos polímeros Lotader® e Lotryl® foram comparados aos dados fornecidos pelo fabricante. Verificou-se que as propriedades de módulo de elasticidade e permeabilidade ao vapor d\' água do filme desenvolvido são inferiores às da poliuretana inviabilizando a substituição. Entretanto, o trabalho proporcionou um melhor entendimento dos fatores que influenciam o módulo de elasticidade e a permeabilidade do novo material ao vapor d\' água. / A polymeric film must have low elasticity modulus and good water vapor permeation to be used in the production of non perforated adhesive tapes. Low modulus is desirable to provide comfort sensation as the consumer moves the part of his or her body in which the tape is applied on, mainly in the articulations regions, as elbows and knees. The importance of good water vapor permeation is related, mainly in the case of non perforated adhesive tapes with the continuous loss of water by the skin. If the film does not allow the release of the water continuously lost by the skin to the environment, the skin will become very sensitiveness as a result of over hydration. This work presents a study of water permeability and a thermal and vibrational characterization of a polymeric film composed of three different polymers developed to replace the adhesive not perforated polyurethane tape providing lower cost. Besides characterization a test of Water Vapor Transmission Rate (WVTR) was performed. Each polymer present in the film composition was analyzed and the results as Tm and chemical structure of Lotader® e Lotryl® were compared with the producer data. It was verified that the properties of elasticity modulus and water vapor permeability of the new material developed are worse than polyurethane so the substitution can not be performed. However, the work provided a better understanding of the factors that influences the elasticity modulus and water vapor permeability of the new material.