No / The effect of matrix polymer and filler content on the rheological behavior of hydroxyapatite-filled injection molding grade high-density polyethylene (HDPE) has been studied. Studies of the flow curves revealed that the matrix and the composite exhibit three distinct regions in the flow curve, namely, a pseudoplastic region at low to moderate shear rates, a plateau and a second pseudoplastic region at high shear rates. The shear stress corresponding to the plateau (Tc) is dependent on both the filler concentration and the melt temperature. Addition of HA in the HDPE matrix increases the value of Tc and decreases compressibility of the melt. An increase in temperature also raises the value of Tc. From the nature of flow curves it is concluded that the matrix polymer largely decides the rheology of the composite.

AD is regarded as a sustainable technology that could assist the UK Government meet internationally agreed GHG emission targets by 2050. However, the mature status of the technology is based on expensive systems that rely on high energy feedstock to be profitable. Meanwhile, the natural biodegradation of cow slurry is a recognised contributor to climate change despite having a relatively low CH4 potential because of the large volumes produced. Economic mixing is essential to the cost-effectiveness of farm AD but techniques applied are not always appropriate as slurry is a shear thinning thixotropic Herschel-Bulkley fluid and therefore challenging to mix. The apparent viscosity of slurry and the shear stress induced was most influenced by solids content (exponential change) followed by temperature (linear). Most shear thinning occurred before a rising shear rate of 20s-1 was achieved with the fluid acting near-Newtonian above. Thixotropic recovery occurred within 1 hour of resting. Rheological values were also much higher than previously reported. Highest CH4 production occurred in the first 10 days of the batch process using a range of mixing regimes with different shear rates and rest periods. During fed-batch operations, changing shear rate had a minimal effect on CH4 production using a 30-day HRT whereas shorter rest periods increased production. Specific CH4 production rate was highest when feeding and mixing coincided. However, when HRT was reduced (OLR increased) the CH4 produced by all mixed regimes significantly increased with highest values being achieved using high intensity mixing rested for short periods. Lower HRTs also requires smaller digesters. Parasitic mixing energy invariably had the most influence on net energy production. Signs of instability were evident after 20 days using the low HRT. Significant microbial adaptation was also observed as the experiments progressed. The research outcomes demonstrate that mixing regime and HRT can be managed to maximise net energy production whilst reducing capital expenditure.

CHARLES UNIVERSITY FACULTY OF PHARMACY IN HRADEC KRÁLOVÉ DEPARTMENT OF PHARMACEUTICAL TECHNOLOGY Author: Tereza Pokorná Title of Diploma thesis Terbinafine-loaded biodegradable polymeric systems for topical administration Supervisor: PharmDr. Eva Šnejdrová, Ph.D. In the diploma thesis the released properties of solid dispersions with terbinafine, based on polyesters of D,L-lactic acid and glycol acid, branched with pentaerythritol and tripentaerythritol are studied. The theoretical part deals with solid dispersions, their classification and methods of preparation, methods of drug dissolution testing, properties, effect, use of terbinafine and preparations containing terbinafine. In the experimental part, solid dispersions were prepared by the melting method. The drug was incorporated into the polyester in the form of a hydrochloride or a base in a concentration of 10 % or 20 %. Some systems were plasticized with 30% triethyl citrate. Thin layers were formulated from solid dispersions, and drug dissolution tests were performed on phosphate buffer pH 7.4 at 37 řC. Assay of terbinafine released was performed spectrophotometrically at 223 nm and ultra-high performance liquid chromatography. Based on the results of this diploma thesis, it can be clearly stated that the suitable carrier of terbinafine...

Piezoelektrické keramické materiály jsou široce používány v mnoha aplikacích a průmyslových odvětvích, nicméně tradiční materiály obvykle obsahují olovo, které je toxické vůči životnímu prostředí. Většina zemí proto zavedla zákony a omezení, které postupně minimalizují spotřebu olova a podporují výzkum v oblasti bezolovnatých kompozic, které by nahradily olověné protějšky. Bezolovnatá piezoelektrická keramika se tak stala žhavým tématem v posledních letech. Nicméně výzkumy na praktické využití bezolovnatých piezoelektrických materiálů jsou jen zřídka publikovány. V této diplomové práci byl vybrán jeden z nadějných kandidátů na piezoelektrickou bezolovnatou keramiku (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 za účelem zkoumání metody snížení jeho vysoké teploty slinování pomocí dotování uhličitanem lithným, kde syntéza prášku byla připravená pomocí techniky sol-gel. Výsledky byly srovnány s konvenčním práškem syntetizovaným v pevné fázi. Vzorky vyrobené ze sol-gel prášku dopovaného 0.5% hmotn. uhličitanem lithným a slinované při 1300 °C po dobu 2 hodin vykazovaly d33 = 447 ± 9 pC N–1, teplotu Curie 98.7 °C a velikost zrn 7.0 ± 0.3 m. Další důležitou otázkou pro aplikace bezolovnatého piezoelektrického keramického materiálu je jeho výroba v různých konfiguracích. Použitím techniky odlévání pásky a aditivních výrobních postupů byla piezoelektrická keramika zpracována do tří různých konfigurací (2-2, 3-3 a 1-3), aby se překlenula mezera mezi materiálovými vědami a materiálovým inženýrstvím. Pro dolévání pásky byly použity suspenze na bázi oleje a vody. Pro přípravu neslinutých keramických fólií bez trhlin, byly pro odlévání na bázi oleje vyvinuty uhlíkové suspenze s obsahem pevných látek 25% hmotn. a BCZT suspenze s obsahem pevných látek 65% hmotn. Problém práškové hydrolýzy ve vodných suspenzích byl vyřešen povrchovou úpravou prášku Al(H2PO4)3, což umožnilo, aby byly tlusté vrstvy bez trhlin odlety v jednom kroku. Tlusté vrstvy slinované při 1500 °C vykazovaly relativní dielektrickou konstantu 1207, dielektrickou ztrátu 0.018 při 1 kHz, remanentní polarizaci 7.54 µC/cm2 a koercitivní síla intenzity pole (Ec) 0.23 kV/mm při 3 kV/mm. Pro tvarování BCZT v konfiguraci 3-3 a 1-3 byla použita přímá metoda tisknutí inkoustu. Pro správnou úpravu tiskového procesu byla použita inkoustová náplň s viskoelastickým chováním obsahující 41.6% obj. pevných látek BCZT a se zpracovatelskými přísadami (HPMC ~ 2.4% a PEI ~ 0.03%). Vzorky v konfiguraci 3-3, slinované při 1500 °C, vykazovaly nejvyšší dielektrické a piezoelektrické vlastnosti, kde Curieho teplota = 86 °C, tan = 0.021, remanentní polarizace = 4.56 µC/cm2 a d33 = 100 ± 4 pC/N. Vzorky v konfiguraci 1-3 slinované při 1500 °C, které byly smíchány s epoxidem, vykazovaly dielektrickou konstantu 144 a dielektrickou ztrátu 0.035 při 1 kHz. Tato práce popisuje tvarování bezolovnaté piezoelektrické keramiky s vynikajícími vlastnostmi v pokročilých strukturách jako krok k návrhu pro moderní senzorické a energy harvesting aplikace.

Aim of this diploma thesis is to choose new pattern wax for Fimes a.s. foundry. New wax should substitute old not fully satisfactory pattern wax which caused problems in technological process resulting in increased number of rejects. New pattern wax should eliminate current problems and help foundry with producing large, thin-walled, high-quality castings. Numbers of pattern waxes supplied by world’s leading wax manufacturers were subjected to laboratory tests and pilot study. This diploma thesis is part of project Alfa TA01010766: „Research and development of production technology large, thin and high quality castings of aluminium alloys “

CHARLES UNIVERSITY FACULTY OF PHARMACY IN HRADEC KRÁLOVÉ DEPARTMENT OF PHARMACEUTICAL TECHNOLOGY Author: Vlastimil Barák Title of Diploma thesis The influence of formulation factors on the characteristics of terbinafine loaded nanoparticles Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Consultant: Mgr. Juraj Martiška The diploma thesis is focused on biodegradable polymer nanoparticles loaded by terbinafine based on the copolymer of glycolic and lactic acid branched on polyacrylic acid. The nanoprecipitation method was employed, and the influence of formulation factors on nanoparticle characteristics was studied. The following formulation factors were the concentration of the polymer, the amount of terbinafine, and the concentration of surfactant. Nanoparticles of 120 nm to 300 nm were obtained depending on the preparation conditions. The nanoparticle polydispersity was in all cases from 0.080 to 0.230. The prepared nanoparticles were stable, as evidenced by zeta potential values above 38 mV. A positive zeta potential is desirable for dermal and mucosal adhesion in the topical and ocular application of nanoparticles with terbinafine. The amount of polymer used to form nanoparticles has the greatest effect on particle size. With increasing polyester concentration in the internal phase, the size of the...

Durch die Kombination verschiedener Werkstoffklassen ermöglichen Hybridverbunde die Entwicklung von Strukturbauteilen, die sich beispielsweise durch eine hohe Festigkeit bei einem gleichzeitig geringen Gewicht auszeichnen. Trotz des großen Einsatzpotentials wurden Hybridverbunde, begründet durch eine kostenintensive und zeitaufwendige Fertigung, bislang nicht für Großserienbauteile vorgesehen. Mit der Konzeption intrinsischer, das heißt einstufiger, Produktionsprozesse wird es jedoch gelingen die Attraktivität zu steigern und damit die Anwendung von Hybridverbunden unter anderem auch in der Automobilindustrie zu etablieren. Exemplarisch soll im Rahmen dieser Arbeit die Entwicklung eines intrinsischen Hybridverbundes für crashbelastete Strukturbauteile simulativ begleitet werden. Der dabei betrachtete Hybridverbund besteht aus einem endlosfaserverstärktem Kunststoff, in den ein metallischer Einleger eingebracht ist. Zur Realisierung der Anbindung der Komponenten sieht das Konzept des Hybridverbundes die Kombination von Form- und Stoffschluss vor. Dabei resultiert der Stoffschluss aus der Beschichtung des metallischen Einlegers, die die Ausbildung eines Interface bewirkt. Zur Realisierung des Formschlusses werden während des überlagerten Umformprozesses lokal Formschlusselemente des metallischen Einlegers in den endlosfaserverstärkten Kunststoff gepresst. Dadurch weisen die resultierenden Bauteile eine komplexe innere Struktur auf, die die simulative Analyse und damit die Bauteilauslegung erschwert. Das Ziel der vorliegenden Arbeit besteht in der Modellierung und Simulation dieses intrinsischen Hybridverbundes. Dazu ist zunächst das Materialverhalten aller Komponenten durch adäquate Materialmodelle für große Deformationen abzubilden. Für deren Entwicklung wird ein Konzept zur Materialmodellierung aufgegriffen und erweitert, das die Formulierung auf der Basis direkt verschalteter rheologischer Elemente ermöglicht. Nach entsprechenden Parameteridentifikationen werden die Materialmodelle im Rahmen von Finite-Elemente-Simulationen eines aus dem Hybridverbund gefertigten Demonstratorbauteils angewendet. Dabei ermöglicht das Vorgehen zur Modellerstellung die Berücksichtigung und Bewertung von Einflüssen der intrinsischen Fertigung auf das Bauteilverhalten. / Hybrid parts, combining for example low weight with high strength, are based on the combination of different material classes. Despite an enormous potential for applications, hybrid composites are not well established for large series parts due to the expensive and complex production. To increase the number of applications, intrinsic, i.e. single-step, manufacturing processes are designed. Within this work, the development of an intrinsic hybrid composite for crash-relevant structural parts is supported by simulations. The considered hybrid composite is made up of a fibre-reinforced polymer, in which a metallic insert is integrated. The connection between these components is based on a combination of geometrical form fit and adhesive bonding. On one hand, adhesive bonds result from a coating of the metallic insert. On the other hand, local form fit elements are pressed into the fibre reinforced polymer during the global forming process. Consequently, the resulting parts, manufactured in just one step, show a complex inner structure, which make simulative analyses and dimensioning more difficult. Within the work at hand, the main research goal is the modelling and simulation of this intrinsic hybrid composite. To this end, the mechanical behaviour of all individual components has to be described by appropriate material models at large strains. For those developments, a concept of material modelling, which enables the formulation based on directly connected rheological elements, is adopted and extended. After identifying the according material parameters, these material models are applied within finite element simulations of a demonstrator made up of the hybrid composite. Thereby, the applied procedure for creating finite element models allows to consider and evaluate how the intrinsic manufacturing process affects the mechanical behaviour of the parts.

Dans le domaine des plastiques biodégradables, les produits se doivent d’être de plus en plus compétitifs. Ces travaux, menés entre le laboratoire IMP@UJM et la société LCI ont eu pour objectif principal l’augmentation de la part en matières d’origines renouvelables dans le mélange de polymères biodégradable poly(butylène adipate-co-téréphtalate) (PBAT)/TPF (farine thermoplastique), sans diminuer ses propriétés mécaniques. Ce mélange est obtenu par extrusion en une seule étape, comprenant la plastification de la farine et le mélange avec le polyester. L’enjeu scientifique était donc en premier lieu de comprendre les relations entre la mise en oeuvre, l’établissement de la morphologie du mélange, la concentration en chacun des polymères et les propriétés mécaniques. Dans un second temps, ces résultats ont été exploités en vue de l’augmentation des propriétés mécaniques du mélange. L’influence de la concentration en TPF et du rapport de viscosité entre les phases a donc été mise en évidence sur toute la gamme de concentration, mettant en lumière l’importance de contrôler la tension interfaciale du mélange. Des mécanismes d’établissement de la morphologie et des interprétations quant à son effet sur les propriétés mécaniques du mélange sont proposés. L’étude d’une modification par extrusion réactive du PBAT est ensuite présentée. L’évolution de la structure du polyester est caractérisée par chromatographie d’exclusion stérique en fonction de différents paramètres, dont le temps de mélange. Enfin, différentes modifications du mélange PBAT/TPF sont testées. L’influence de la modification du PBAT, de la modification de la phase TPF ou de la modification de l’interface via des agents compatibilisants est étudiée sur les propriétés rhéologiques, morphologiques et mécaniques du mélange / Biodegradable plastics need to be more and more competitive. This work, conducted between IMP@UJM laboratory and LCI company had the main objective of increasing the content of renewable materials in the biodegradable blend of poly(butylene adipate-co-terephthalate) (PBAT)/ thermoplastic flour (TPF), without decreasing its mechanical properties. The blend was obtained by a single step extrusion, including flour thermoplastification and blending with the polyester. The scientific challenge was to understand the relationship between processing parameters, the morphology establishment, the concentration of each phase of the blend and its mechanical properties. Then, these results were exploited in order to increase the mechanical properties of the mixture. The influence of the concentration of TPF and the viscosity ratio between the phases was highlighted over the entire concentration range. This highlighted the importance of controlling the interfacial tension of the blend. Mechanisms of the morphology establishment were proposed, as well as interpretations about its effect on the mechanical properties of the blend. Then, a study of the PBAT modification by reactive extrusion was proposed. The evolution of the polyester structure was characterized by size exclusion chromatography, according to various parameters including the mixing time. Finally, various modifications of PBAT/TPF mixture were tested. Modifying the PBAT, the TPF phase or the interface via the compatibilizers were studied in order to tailor the rheological, morphological and mechanical properties

The physicochemical properties of tuna protein hydrolysates were enhanced by interaction with sodium alginate. The increase in emulsifying capacity and stability was from 50 to 150 m² g⁻¹ and from 36 to 49 min, respectively. The increase in foaming capacity and stability was from 100% to 140% and from 65% to 70%, respectively. The reason for the increased physicochemical properties was the reduced zeta potential level of tuna protein hydrolysates after interaction with sodium alginate. The change in internal structure of tuna protein hydrolysates after interaction with sodium alginate was determined by SEM and FTIR. The SEM results showed that a net cross-linking structure was formed from a sheet structure after the tuna protein hydrolysates interacted with sodium alginate. FTIR demonstrated that parts of the β-sheet of tuna protein hydrolysates were changed into an irregular coiled structure or α-helix after interaction with sodium alginate. In order to understand the interacted complex better, the rheological properties of interacted tuna protein hydrolysates with sodium alginate were further determined. In this study, the one-step was developed, easy-to-operate and cost-effective process that can further add value to tuna protein hydrolysates derived from tuna processing by-products.

In this thesis we design and develop algorithms for predicting the rheological behavior of polymer melts based on the results of detailed atomistic simulations and guided by theories of the Dynamics of Polymers and fundamental Principles of Science of the Non-Equilibrium Thermodynamics. More specifically: 1) We propose a new rheological constitutive model for the time evolution of the tensor conformation tensor C of chains in a polymer melt (and hence the stress tensor τ) using the generalized bracket formalism of Beris and Edwards. The new constitutive model includes terms that describe a whole range of phenomena and are successfully used to describe the rheological properties of commercial polyethylene resins. 2) We developed a new methodology that allows direct connection of the results of atomistic simulations with molecular reptation theory for entangled polymers. The final result of the methodology is the calculation of the function ψ(s,t) which expresses the probability that the segment s along the contour of the primitive path remain in the original tube after time t. 3) We extended the Rouse theory for systems without polymer chain ends, as the polymer rings. While there have been previous theoretical work, a comprehensive analysis of the Rouse model of cyclic polymers was still lacking; here we develop the theory in its entirety. / Στα πλαίσια της παρούσας διατριβής σχεδιάσαμε και αναπτύξαμε αλγορίθμους πρόβλεψης της ρεολογικής συμπεριφοράς πολυμερικών τηγμάτων βασιζόμενοι στα αποτελέσματα λεπτομερών ατομιστικών προσομοιώσεων, καθοδηγούμενοι όμως από Θεωρίες της Δυναμικής των Πολυμερών αλλά και από θεμελιώδεις αρχές της Επιστήμης της Θερμοδυναμικής Εκτός Ισορροπίας. Πιο συγκεκριμένα: 1) Προτείνουμε αρχικά ένα νέο ρεολογικό καταστατικό μοντέλο για τη χρονική εξέλιξη του τανυστή διαμορφώσεων C των αλυσίδων σε ένα πολυμερικό τήγμα (και κατ’ επέκταση για τον τανυστή των τάσεων τ) κάνοντας χρήση του φορμαλισμού των γενικευμένων αγκυλών των Beris και Edwards. Το νέο καταστατικό μοντέλο περιλαμβάνει όρους που περιγράφουν ένα ολόκληρο φάσμα φαινομένων και χρησιμοποιήθηκε με επιτυχία για την περιγραφή των ρεολογικών ιδιοτήτων εμπορικών ρητινών πολυαιθυλενίου. 2) Αναπτύξαμε μια καινούργια μεθοδολογία που επιτρέπει την άμεση σύνδεση των αποτελεσμάτων των ατομιστικών προσομοιώσεων με τη μοριακή θεωρία του ερπυσμού για διαπλεγμένα πολυμερή. Το τελικό αποτέλεσμα της μεθοδολογίας είναι ο υπολογισμός της συνάρτησης ψ(s,t) που εκφράζει την πιθανότητα το σημείο s κατά μήκος του περιγράμματος του πρωτογενούς δρόμου των αλυσίδων να παραμένει στον αρχικό σωλήνα μετά από χρόνο t. Επεκτείναμε τη θεωρία Rouse και για συστήματα πολυμερικών αλυσίδων δίχως άκρα, όπως αυτά των πολυμερικών δακτυλίων. Παρότι στίγματα της θεωρίας είχαν παρουσιαστεί και σε προηγούμενες εργασίες από άλλους ερευνητές, στην παρούσα διατριβή αναπτύξαμε τη θεωρία στην ολότητά της.