In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.

Benzo[a]pyrene (BaP) is a human carcinogen, which is metabolized by a variety of enzyms such as cytochrome P450 (CYP) and epoxide hydrolase. The aim of this work was to study BaP metabolism in vitro by the hepatic microsomal system of rats treated with CYP inducers and by human cytochrome P450 1A1 (CYP1A1) expressed in eukaryotic and prokaryotic systems. An eukaryotic expression system consisted of microsomes isolated from insect cells, whereas a prokaryotic expression system was formed by the membrane fragments of E. coli. In the case of recombinant human CYP1A1, we investigated the influence of cytochrome b5, NADPH:cytochrome P450 reductase (CPR) and epoxide hydrolase in BaP oxidation. Isolation and purification of rabbit hepatic CPR was another aim of this work. BaP metabolites were separated by HPLC. The results found in this work demostrate the fact that hepatic microsomal systems of rats treated with an inducer of CYP1A (Sudan I), an inducer of CYP2B (phenobarbital) and an inducer of CYP3A (PCN) exhibit higher efficiency of BaP oxidation than microsomes of control rats. BaP is oxidized by human CYP1A1 expressed in the eukaryotic system to six metabolites (BaP-9,10-dihydrodiol, BaP metabolite with unknown structure, BaP-7,8-dihydrodiol, BaP-1,6-dion, BaP-3,6-dion, BaP-3-ol), whereas by human...

A study of an influence of strengthening steel beams using reinforcement based on FRP on a moment bearing resistance and bending stiffness. Evaluation of the theoretical calculation methods based on the performed experimental verification. Description of the production of carbon fibres and composite materials on the basis of carbon fibres.

Introduction: Epoxyeicosatrienoic acids (EETs) are converted by the enzyme soluble epoxid hydrolase (sEH) to the biologically inactive dihydroxyeicosatrienoic acids (DHETs). EETs are significantly involved in the control of blood pressure, they influence vascular tone and renal transport mechanism. sEH inhibitor reduce blood pressure by increasing the bioavailability of EETs in many models of hypertension. Aim of the study: To determine that sEH inhibitor decreases blood pressure and improves the renal function during the development of malignant hypertension in transgenic rats after the induction of the mouse renin gene. Methods: Hypertension in Cyp1a1-Ren-2 transgenic rats was induced through a dietary administration of the natural xenobiotic indole-3-carbinol (I3C, 0.3 %) for 3 and 11 days. I3C activates the renin gene. At the same time, during a three-day induction of hypertension, the inhibitor of nitric oxide synthase L-NAME (600 mg/l) was administered in drinking water. The sEH inhibitor c-AUCB was given in drinking water at a dose of 13 or 26 mg/l, starting 48 hours before the initiation of I3C and L-NAME administration. Radiotelemetric measurement of blood pressure was performed and renal excretory parameters were monitored in the conscious animals. The effects on renal hemodynamics and...

The poly(glycidyl methacrylate)-modified magnetite nanoparticles, Fe3O4-PGMA NPs, were investigated and applied in nondestructive flaw detection of polymeric materials in this research. The Fe3O4 endowed magnetic property to the materials for flaw detection while the PGMA promoted colloidal stability and prevented particle aggregation. The magnetite nanoparticles (Fe3O4 NPs) were successfully synthesized by coprecipitation and then surface-modified with PGMA to form PGMA-modified Fe3O4 NPs by both grafting-from and grafting-to approaches. For the grafting-from approach, the Fe3O4 NPs were surface-functionalized with α-bromo isobutyryl bromide (BIBB) to form BIB-modified Fe3O4 NPs (Fe3O4-BIB NPs) with covalent linkage. The resultant Fe3O4-BIB NPs were used as surface-initiators to grow PGMA by surface-initiated atom transfer radical polymerization (SI-ATRP). For the grafting-to approach, the Fe3O4 NP were surface-functionalized with (3-mercaptopropyl)triethoxysilane (MCTES) to form MCTES-modified Fe3O4 NPs (Fe3O4-MCTES NPs). The PGMA with Br-end group was pre-synthesized by ATRP and then was grafted to the surface of the Fe3O4-MCTES NPs by coupling reaction. Both bare and modified Fe3O4 NPs exhibited superparamagnetism and the existence of iron oxide in the form of Fe3O4 was confirmed. The particle size of individual Fe3O4 NPs was about 8 – 24 nm but they aggregated to form clusters. The PGMA-modified NPs formed stable dispersion in chloroform and had larger cluster sizes than the unmodified ones because of the PGMA polymer layer. However, the uniformity of the NP clusters could be improved with PGMA surface grafting. The PGMA surface layer of the grafting-from (Fe3O4-gf-PGMA) NPs was thin and dense while that of the grafting-to (Fe3O4-gt-PGMA) NPs was thick and loose. The hydrodynamic diameters (Zave) of Fe3O4-gf-PGMA NP clusters could be controlled between 176 to 643 nm, dependent on the PGMA contents and reaction conditions. During SI-ATRP, side reactions happened and caused NP aggregation as well as increase of size of NP clusters. However, the aggregation has been minimized through optimization of reaction conditions. Oppositely, Zave values of Fe3O4-gt-PGMA NPs had little variation of about 120 – 190 nm. And the PGMA content of the Fe3O4-gt-PGMA NPs was limited to 12.5% because of the spatial hindrance during grafting process. The saturation magnetization (Ms) of the unmodified Fe3O4 NPs was about 77 emu/g, while those of the grafting-from and grafting-to Fe3O4-PGMA NPs were 50 – 66 emu/g and 63 – 70 emu/g, respectively. For Fe3O4-PGMA NPs with similar Fe3O4 contents, the grafting-to NPs had slightly higher Ms than the grafting-from counterparts. In addition, the Ms of both kinds of the Fe3O4-PGMA NPs with higher Fe3O4 content (> 87%) were also higher than that of the fluidMAG-Amine, the commercially available amine-modified MNPs. Besides, both kinds of Fe3O4-PGMA NPs also had much higher Fe3O4 contents and Ms values than most of the reported PGMA-modified MNPs. The magnetic epoxy nanocomposites (MENCs) were prepared by blending the modified Fe3O4 NPs into bisphenol A diglycidyl ether (BADGE)-based epoxy system and the distributions of both kinds of the PGMA-modified NPs were much better than that of the oleic acid-modified Fe3O4 NPs. Similar to the NPs, the MENCs also exhibited superparamagnetism. By cross-section TEM observation, the grafting-to Fe3O4-PGMA NPs formed more homogeneous distributions with smaller cluster size than the grafting-from counterparts and gave higher Ms of the MENCs. Nondestructive flaw detection of surface and sub-surface defects could be successfully achieved by brightness contrast of images given through eddy current testing (ET) method, which is firstly reported. The mechanical properties of the materials were influenced very slightly when 2.5% or lower Fe3O4-gt-PGMA NPs were present while the presence of the Fe3O4-gf-PGMA NPs (1 – 2.5 %) gave mild improvement of the storage modulus and increase of the glass-rubber transition temperature(Tg) of the MENCs. Furthermore, the Fe3O4-PGMA NPs could be evenly coated onto the functionalized ultra-high molecular weight poly(ethylene) (UHMWPE) textiles. The Fe3O4-gt-PGMA NPs were coated on the textile in order to prepare NP-coated textile-reinforced composite. Preliminary result of ET measurement showed that the Fe3O4-gt-PGMA NPs coated on the textiles could visualize the structure of the textile hidden inside and their relative depth. Accordingly, the incorporation of MNPs to polymers opens a new pathway of damage-free structural health monitoring of polymeric materials.

The poly(glycidyl methacrylate)-modified magnetite nanoparticles, Fe3O4-PGMA NPs, were investigated and applied in nondestructive flaw detection of polymeric materials in this research. The Fe3O4 endowed magnetic property to the materials for flaw detection while the PGMA promoted colloidal stability and prevented particle aggregation. The magnetite nanoparticles (Fe3O4 NPs) were successfully synthesized by coprecipitation and then surface-modified with PGMA to form PGMA-modified Fe3O4 NPs by both grafting-from and grafting-to approaches. For the grafting-from approach, the Fe3O4 NPs were surface-functionalized with α-bromo isobutyryl bromide (BIBB) to form BIB-modified Fe3O4 NPs (Fe3O4-BIB NPs) with covalent linkage. The resultant Fe3O4-BIB NPs were used as surface-initiators to grow PGMA by surface-initiated atom transfer radical polymerization (SI-ATRP). For the grafting-to approach, the Fe3O4 NP were surface-functionalized with (3-mercaptopropyl)triethoxysilane (MCTES) to form MCTES-modified Fe3O4 NPs (Fe3O4-MCTES NPs). The PGMA with Br-end group was pre-synthesized by ATRP and then was grafted to the surface of the Fe3O4-MCTES NPs by coupling reaction. Both bare and modified Fe3O4 NPs exhibited superparamagnetism and the existence of iron oxide in the form of Fe3O4 was confirmed. The particle size of individual Fe3O4 NPs was about 8 – 24 nm but they aggregated to form clusters. The PGMA-modified NPs formed stable dispersion in chloroform and had larger cluster sizes than the unmodified ones because of the PGMA polymer layer. However, the uniformity of the NP clusters could be improved with PGMA surface grafting. The PGMA surface layer of the grafting-from (Fe3O4-gf-PGMA) NPs was thin and dense while that of the grafting-to (Fe3O4-gt-PGMA) NPs was thick and loose. The hydrodynamic diameters (Zave) of Fe3O4-gf-PGMA NP clusters could be controlled between 176 to 643 nm, dependent on the PGMA contents and reaction conditions. During SI-ATRP, side reactions happened and caused NP aggregation as well as increase of size of NP clusters. However, the aggregation has been minimized through optimization of reaction conditions. Oppositely, Zave values of Fe3O4-gt-PGMA NPs had little variation of about 120 – 190 nm. And the PGMA content of the Fe3O4-gt-PGMA NPs was limited to 12.5% because of the spatial hindrance during grafting process. The saturation magnetization (Ms) of the unmodified Fe3O4 NPs was about 77 emu/g, while those of the grafting-from and grafting-to Fe3O4-PGMA NPs were 50 – 66 emu/g and 63 – 70 emu/g, respectively. For Fe3O4-PGMA NPs with similar Fe3O4 contents, the grafting-to NPs had slightly higher Ms than the grafting-from counterparts. In addition, the Ms of both kinds of the Fe3O4-PGMA NPs with higher Fe3O4 content (> 87%) were also higher than that of the fluidMAG-Amine, the commercially available amine-modified MNPs. Besides, both kinds of Fe3O4-PGMA NPs also had much higher Fe3O4 contents and Ms values than most of the reported PGMA-modified MNPs. The magnetic epoxy nanocomposites (MENCs) were prepared by blending the modified Fe3O4 NPs into bisphenol A diglycidyl ether (BADGE)-based epoxy system and the distributions of both kinds of the PGMA-modified NPs were much better than that of the oleic acid-modified Fe3O4 NPs. Similar to the NPs, the MENCs also exhibited superparamagnetism. By cross-section TEM observation, the grafting-to Fe3O4-PGMA NPs formed more homogeneous distributions with smaller cluster size than the grafting-from counterparts and gave higher Ms of the MENCs. Nondestructive flaw detection of surface and sub-surface defects could be successfully achieved by brightness contrast of images given through eddy current testing (ET) method, which is firstly reported. The mechanical properties of the materials were influenced very slightly when 2.5% or lower Fe3O4-gt-PGMA NPs were present while the presence of the Fe3O4-gf-PGMA NPs (1 – 2.5 %) gave mild improvement of the storage modulus and increase of the glass-rubber transition temperature(Tg) of the MENCs. Furthermore, the Fe3O4-PGMA NPs could be evenly coated onto the functionalized ultra-high molecular weight poly(ethylene) (UHMWPE) textiles. The Fe3O4-gt-PGMA NPs were coated on the textile in order to prepare NP-coated textile-reinforced composite. Preliminary result of ET measurement showed that the Fe3O4-gt-PGMA NPs coated on the textiles could visualize the structure of the textile hidden inside and their relative depth. Accordingly, the incorporation of MNPs to polymers opens a new pathway of damage-free structural health monitoring of polymeric materials.:1. Introduction 2. Theoretical section 2.1. Magnetite Nanoparticles (MNPs) 2.2. Applications of MNPs 2.3. Atom transfer radical polymerization (ATRP) 2.4. Magnetic nanocomposites (MNCs) 2.5. Damage-free structural health monitoring (SHM) using MNPs 3. Objective of the work 4. Materials, methods and characterization 4.1. Materials 4.2. Methods 4.3. Formation of polymeric magnetic nanocomposites 4.4. Characterization 5. Results and discussions 5.1. Unmodified magnetite nanoparticles (Fe3O4 NPs) 5.2. Oleic acid-modified (Fe3O4–OA) NPs 5.3. PGMA-modified NPs by grafting-from approach (Fe3O4-gf-PGMA NPs) 5.4. PGMA-modified NP by grafting-to approach (Fe3O4-gt-PGMA NPs) 5.5. Comparison between grafting-from and grafting-to Fe3O4-PGMA NPs 5.6. Magnetic epoxy nanocomposites (MENCs) 5.7. Fiber-reinforced epoxy nanocomposites 6. Conclusions and outlook 7. Appendix 8. List of figures, schemes and tables 9. References Versicherung Erklaerung List of publications

In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.

Monolithische Phasen werden seit ca. 20 Jahren entwickelt und sind in den letzten Jahren eine attraktive Alternative zu etablierten mit Partikeln gefüllten Säulen geworden. Sie werden in anorganische Phasen und organische Polymermonolithe unterteilt. Monolithe bestehen aus einem einzigen, durchgehenden Stück. Charakteristisch ist das sie durchziehende Porennetzwerk, durch das der Eluent mit geringerem hydraulischen Widerstand fließen kann und das somit schnellere Flussraten ermöglicht. Polymermonolithe werden vorwiegend für die Separation großer Biomoleküle aufgrund eines durch Konvektion beschleunigten Massentransfers eingesetzt. Zudem sind sie über einen breiten pH-Wert-Bereich stabil und können direkt (in situ) im gewünschten Format polymerisiert werden. In der vorliegenden Arbeit gelang die Herstellung neuartiger epoxidbasierter Phasen nach einem von Weller et al. entwickelten Konzept, die im Affinitätsexperiment angewendet wurden. Die Herstellung erfolgte durch Autopolymerisation polyfunktioneller Glycidylether. Für die Funktionalisierung wurden nicht polymerisierte Epoxide genutzt. Als Monomere dienten TEPIC, GE 100 sowie GE 500. Die Arbeiten konzentrierten sich vor allem auf die bei Raumtemperatur durchführbaren Synthesen mit dem höher funktionellen GE 500. Die Polymerisationsbedingungen wurden hinsichtlich Porogenmischung und -anteil optimiert. Eine mit 75 Vol.-% Porogen (Dioxan/ MTBE (2:3)) hergestellte und mit rProtein A funktionalisierte Kapillarsäule (66 %, 12 µm, 7m2/g) ergab im Affinitätsexperiment eine Kapazität von 0,44 mg/mL aus Kaninchenserum isolierbarem IgG. Durch Beimischung von 60 % BDE konnte der Epoxidgehalt vervierfacht und die Porengröße auf 400 nm bei 59 % Porosität reduziert werden. Die spezifische Oberfläche wurde verdreifacht und die Kapazität präparierter Disks auf 0,90 mg/mL etwa verdoppelt. Die in dieser Arbeit entwickelten Disks können zur Isolierung von IgG aus einer komplexen Probe, wie beispielsweise Blutserum, eingesetzt werden. / Monolithic supports have been developed since 20 years and have become an attractive alternative to well-established columns packed with particles over the past years. They are classified into inorganic media and organic polymer monoliths. Monoliths consist of a single, continuous piece with an integrated characteristic porous network through which the eluent can flow with lower hydraulic resistance and which consequently offers higher flow rates. Due to an accelerated mass transfer caused by convection polymer monoliths are mainly used for separation of large biomolecules. In addition, they are stable over a wide pH range and can be polymerized directly (in situ) in the desired format. In the present work the successful preparation of new epoxide-based supports according to a concept introduced by Weller et al. as well as their application in affinity chromatography are reported. Their preparation was carried out by self-polymerization of polyfunctional glycidyl ethers and for functionalization non-polymerized epoxide groups were used. As monomers TEPIC, GE 100 and GE 500 were utilized. The work has focused especially on the polymerization of the higher functional GE 500, which can be perfomed at room temperature and was optimized in terms of both composition and amount of porogen. The extraction of IgG from rabbit serum with a capillary column (66 %, 12 µm, 7m2/g) prepared by 75 vol.-% porogen (dioxane/ MTBE (2:3)) and functionalized with rprotein A resulted in a capacity of 0,44 mg/mL. By addition of 60 % BDE the epoxide content was quadrupled and the pore size reduced to 400 nm while maintaining consistently high porosity of 59 %. The specific surface area was tripled and the capacity of prepared disks approximately doubled to 0,90 mg/mL. The disks developed in this work can be applied for the isolation of IgG from complex samples such as serum.