Search for dissertations about: "crazing"

Found 5 swedish dissertations containing the word crazing.

2. 1. Hydrolytic degradation of dental composites and effects of silane-treatment and filler fraction on compressive strength and thermal expansion of composites

   Author : Karl-Johan M. Söderholm; Umeå universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Internal frictional theory; filler-matrix debonding; stress-corrosion; stressinfluenced diffusion; m icro-crack form ation; crazing; opacity; wear; osmotic pressure; hoop stresses;

   Abstract : Some researchers have suggested that the weakest link of dental composites is the filler-matrix bond. However, due to incompleteness of information dealing with this bond and its stability in a humid environment, it was considered desirable to investigate the effect of water on this region, as well as the influence of filler bonding and filler fraction on compressive strength and thermal expansionExperimental composites containing different filler fractions of either silane-treated or untreated fillers were made. READ MORE

4. 2. Processing and Properties of Nanostructured Biocomposites

   Author : Natalia Herrera Vargas; Maria Soledad Peresin; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Trä och bionanokompositer; Wood and Bionanocomposites;

   Abstract : In this work, nanostructured biocomposite fibers and films with cellulose nanofibers (CNF), cellulose nanocrystals (CNC) and chitin nanocrystals (ChNC) were prepared using solutions mixing followed by electrospinning and melt compounding. The main processing challenges for these materials were to find parameters for: 1) fiber alignment in electrospinning, 2) feeding the nanomaterials into the extruder and 3) dispersion and distribution of the nanomaterials in the polymeric matrix. READ MORE

5. 3. Processing and properties of nanocomposites based on polylactic acid, chitin and cellulose

   Author : Natalia Herrera Vargas; Kristiina Oksman; Aji P. Mathew; Jyrki Vuorinen; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nanocomposite; Cellulose; Chitin; Extrusion; Polylactic acid; Trä och bionanokompositer; Wood and Bionanocomposites;

   Abstract : The production of bio-based and biodegradable nanocomposites has gained attention during recent years for environmental reasons; however, the large-scale production of these nanocomposites still poses challenges. The objective of this work has been to prepare bio-based and biodegradable nanocomposites via liquid-assisted extrusion and to gain a deeper understanding of the process and the relationship between the process, composition, structure and properties. READ MORE

6. 4. Silicone obturators and the bacterial flora in symptomatic nasal septal perforations

   Author : Anna Karin Hulterström; Anders Berglund; Diana Berggren; Åke Davidsson; Umeå universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Nasal mucosa; perforation; symptomatic; inflammation; Staphylococcus aureus; obturator treatment; medical silicone; wettability;

   Abstract : Background A perforation in the nasal septum can cause symptoms such as bleeding, obstruction, crusts and pain, and can be a challenge to treat. Surgery is the treatment of choice, but disease, size of the perforation, or the patient’s wish may contradict surgery. READ MORE

7. 5. Properties of poly(lactic acid) in presence of cellulose and chitin nanocrystals

   Author : Shikha Singh; Kristiina Oksman; Maria Lluisa Maspoch; Alfonso Jiménez; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; poly lactic acid ; chitin nanocrystals; nanocellulose; crystallization; orientation; nanocomposites; mechanical properties-other properties; Trä och bionanokompositer; Wood and Bionanocomposites;

   Abstract : Plastic based materials are widely used for industrial and domestic packaging application. However, disposal of such petroleum-based materials e.g. polyethylene (PE), polypropylene (PP), and polyethyleneterephthalate (PET) has become a huge threat to the environment. READ MORE