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Synthese von Übergangsmetallformiaten und deren Verwendung zur MetallisierungAbylaikhan, Akerke 29 September 2005 (has links)
In der vorliegenden Arbeit werden M(II)-Formiat-Komplexe mit M=Cu, Ni, Zn beschrieben. Das
themogravimetrische Verhalten dieser Komplexe wird vorgestellt. TG-MS-Untersuchungen geben
erste Hinweise auf das Metallisierungsverhalten obiger Spezies. Die Charakterisierung der
entsprechenden Komplexe erfolgte durch die Elementaranalyse, IR-Spektroskopie sowie in
einzelnen Fällen durch die Einkristallröntgendiffraktometrie.
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Fázové transformace v hořčíkových slitinách typu MgZnAl. / Phase transformation in magnesium MgZnAl-based alloysKodetová, Veronika January 2016 (has links)
In the present work, there was analyzed thermal evolution of the phase transformation in the MgZnAl and MgZnAlCa alloys with different concentration of the Zn and Ca. The grains were occupied by the phase with quasicrystaline icosaedral structure in the as-cast alloys and after isochronal annealing up to 240 řC. The thermal measurements revealed two exothermic effects in the MgZnAl alloy and three exothermic effects in the MgZnAlCa alloy during linear heat treatment in the temperature range of 100 - 250 řC. In agreement to the thermal response, two and three stages of electrical resistivity decrease were observed in the same temperature range. The lower thermal changes, absolute resistivity changes and microhardness were observed in the alloy with Ca-addition and lower concentration of Zn.
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Biodegradation and ageing of bio-based thermosetting resins from lactic acidGomes Hastenreiter, Lara Lopes January 2019 (has links)
The need for replacing petroleum-based polymers has been increasing and bio-based polymers prove to be a suitable solution. The aim of this thesis was to synthesize bio-based resins with different chemical architectures to evaluate the effect of the structure on the properties and on their response to ageing and biodegradation. For this, three different bio-based thermoset resins have been synthesised by reacting one of three distinct core-molecules with lactic acid. The options of core-molecules chosen for this work were ethylene glycol, glycerol and pentaerythritol. Lactic acid was first reacted with a core-molecule by direct condensation, the resulting branched molecule was then end-functionalized with methacrylic anhydride. The amount of moles of lactic acid varied according to which core-molecule it was reacted with, but the chain length (n) was always maintained as three. Part of the samples were characterised by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile test. DSC and TGA were used for determining the thermal behaviour. FT-IR was used to verify the first and second stage of the reaction and to ascertain the occurrence of the crosslinking reaction. Tensile test was done for investigation of mechanical properties. The ageing and biodegradation tests are useful to ascertain the material possible applications. Therefore, the samples that went through the process of ageing or biodegradation were also characterised in the end of the procedures to further check the effect of those processes on the specimens. The test results indicated that the PENTA/LA cured resin was the most stable thermally. The cured resin’s mechanical properties were similar to each other, so there was no comparison to make in this area. The samples proved to be affected by the biodegradation and the ageing processes, both in visual and structural aspects.
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High-Density Polyethylene/Peanut Shell BiocompositesLondoño Ceballos, Mauricio 05 1900 (has links)
A recent trend in the development of renewable and biodegradable materials has led to the development of composites from renewal sources such as natural fibers. This agricultural activity generates a large amount of waste in the form of peanut shells. The motivation for this research is based on the utilization of peanut shells as a viable source for the manufacture of biocomposites. High-density polyethylene (HDPE) is a plastic largely used in the industry due to its durability, high strength to density ratio, and thermal stability. This research focuses in the mechanical and thermal properties of HDPE/peanut shell composites of different qualities and compositions. The samples obtained were subjected to dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and mechanical tensile strength tests. TO prepare the samples for analysis, the peanut shells were separated into different mesh sizes and then mixed with HDPE at different concentrations. The results showed that samples with fiber size number 10 exhibited superior strength modulus of 1.65 GPa versus results for HDPE alone at 1.32 GPa. The analysis from the previous experiments helped to determine that the fiber size number 10 at 5%wt. ratio in HDPE provides the most optimal mechanical and thermal results. From tensile tests the highest modulus of elasticity of 1.33 GPa was achieved from the samples of peanut shells size number 10 in HDPE at 20%wt. ratio, while the results for HDPE alone were only of 0.8 GPa. The results proved the hypothesis that the addition of peanut shells to HDPE enhances both the thermal and mechanical properties of the composite.
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Charakterizace silikonových gelů pro hojení jizev / Characterization of silicone scar treatment gelsPodzimková, Alena January 2021 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Alena Podzimková Title of Thesis: Characterization of silicone scar treatment gels Supervisor: PharmDr. Eva Šnejdrová, Ph.D. This diploma thesis deals with characterization of silicone gels by various methods, specifically measurement of rheological properties, overall characterization of the composition by infrared spectroscopy, identification of volatile compounds by gas chromatography and determination of molecular weight distribution of polymers by gel permeation chromatography. The theoretical part provides information about scars and their treatment options and describes the principles and the evaluation of tests performed in the experimental part. Five commercial gels and three newly formulated scar healing gels were evaluated. Analysis of viscosity curves confirmed newtonian type of flow in commercial gels Scar Gel Dr. Max and Stratamed and in the newly formulated gels. Strataderm, RejuvaSil and ScarEsthetique show a decrease in viscosity under stress. Oscillation tests have shown a gel structure only with the commercial ScarEsthetique and RejuvaSil. Scar Gel Dr. Max, Strataderm, the newly formulated gels and Stratamed contain polymeric polydimethylsiloxane. In case of Scar...
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Correlating Melt Dynamics with Topological Phases of Homogeneous Chalcogenide- and Modified Oxide- Glasses Using Raman Scattering, Infra-Red Spectroscopy, Modulated-Differential Scanning Calorimetry and Volumetric ExperimentsChbeir, Ralph January 2019 (has links)
No description available.
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Vibrational spectroscopic techniques (Raman, FT-IR and FT-NIR spectroscopy) as a means for the solid-state structural analysis of pharmaceuticalsAli, H.R.H. January 2009 (has links)
The aim of this work was to assess the suitability of vibrational spectroscopic
techniques (Raman, FT-IR and FT-NIR spectroscopy) as a means for the solid-state
structural analysis of pharmaceuticals. Budesonide, fluticasone propionate, salbutamol
hemisulfate, terbutaline hemisulfate, ipratropium bromide, polymorphic forms of
salmeterol xinafoate and two polymorphic forms of sulfathiazole were selected since
they are used in the management of certain respiratory disorders and from different
chemical and pharmacological entities along with some pharmaceutical excipients.
Conventional visual examination is not sufficient to identify and differentiate spectra
between different pharmaceuticals. To confirm the assignment of key molecular
vibrational band signatures, quantum chemical calculations of the vibrational spectra
were employed for better understanding of the first five selected drugs. The nondestructive
nature of the vibrational spectroscopic techniques and the success of
quantum chemical calculations demonstrated in this work have indeed offered a new
dimension for the rapid identification and characterisation of pharmaceuticals and
essentially warrant further research.
The application of simultaneous in situ Raman spectroscopy and differential
scanning calorimetry for the preliminary investigation of the polymorphic
transformation of salmeterol xinafoate polymorphs and two polymorphic forms of
sulfathiazole has also been explored in this work leading to the development of a new
method for the solid-state estimation of the transition temperature of
entantiotropically related pharmaceutical polymorphs which represents the first
analytical record of the use of this approach for pharmaceutical polymorphs.
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Analytical method development for structural studies of pharmaceutical and related materials in solution and solid state. An investigation of the solid forms and mechanisms of formation of cocrystal systems using vibrational spectroscopic and X-ray diffraction techniquesElbagerma, Mohamed A. January 2010 (has links)
Analysis of the molecular speciation of organic compounds in solution is essential for the
understanding of ionic complexation. The Raman spectroscopic technique was chosen for
this purpose because it allows the identification of compounds in different states and it
can give information about the molecular geometry from the analysis of the vibrational
spectra. In this research the ionisation steps of relevant pharmaceutical material have been
studied by means of potentiometry coupled with Raman spectroscopy; the protonation
and deprotonation behaviour of the molecules were studied in different pH regions. The
abundance of the different species in the Raman spectra of aqueous salicylic acid,
paracetamol, citric acid and salicylaldoxime have been identified, characterised and
confirmed by numerical treatment of the observed spectral data using a multiwavelength
curve-fitting program. The non-destructive nature of the Raman spectroscopic technique
and the success of the application of the multiwavelength curve-fitting program
demonstrated in this work have offered a new dimension for the rapid identification and
characterisation of pharmaceuticals in solution and have indicated the direction of further
research.
The work also covers the formation of novel cocrystal systems with pharmaceutically
relevant materials. The existence of new cocrystals of salicylic acid-nicotinic acid, DLphenylalanine
, 6-hydroxynicotinic acid, and 3,4-dihydroxybenzoic acid with oxalic acid
have been identified from stoichiometric mixtures using combined techniques of Raman
spectroscopy (dispersive and transmission TRS), X-ray powder diffraction and thermal
analysis. Raman spectroscopy has been used to demonstrate a number of important
aspects regarding the nature of the molecular interactions in the cocrystal. Cocrystals of
II
salicylic acid ¿ benzamide, citric acid-paracetamol and citric acid -benzamide have been
identified with similar analytical approaches and structurally characterised in detail with
single crystal X-ray diffraction.
From these studies the high selectivity and direct micro sampling of Raman spectroscopy
make it possible to identify spectral contributions from each chemical constituent by a
peak wavenumber comparison of single-component spectra (API and guest individually)
and the two- component sample material (API/guest), thus allowing a direct assessment of
cocrystal formation to be made. Correlation of information from Raman spectra have
been made to the X-ray diffraction and thermal analysis results.
Transmission Raman Spectroscopy has been applied to the study cocrystals for the first
time. Identification of new phases of analysis of the low wavenumber Raman bands is
demonstrated to be a key advantage of the TRS technique. / Libyan government and Misurata University
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New Insights into Topological Phases in (Na2O)x(P2O5)100-x glasses from Enthalpy of Relaxation at Tg from Modulated-DSC and LO- and TO- mode frequency splitting from IR reflectanceGOGI, VAMSHI KIRAN 04 November 2020 (has links)
No description available.
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Study of Drug Delivery Behavior Through Biomembranes Using Thermal And Bioanalytical TechniquesVenumuddala, Hareesha Reddy January 2010 (has links)
No description available.
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