EFFECT OF ALIGNMENT, SIZING, AND MANUFACTURING METHOD ON MECHANICAL PROPERTIES OF RECYCLED CARBON FIBER COMPOSITES

The exceptional combination of properties offered by carbon fiber composites has propelled their incorporation into high performance markets such as aerospace, wind energy, luxury cars and sporting goods. While the use of carbon fiber in these sectors is expected to continue to increase, the high price and energy cost associated with carbon fiber production acts as a significant barrier of entry into larger volume markets, such as the automotive industry. One method of navigating this transition is through the use of recycled carbon fiber composites. Carbon fiber reclamation can produce fibers with up to 90% and 100% of the strength and stiffness, respectively, and 25% and 10-20% of the cost and production energy, respectively, of virgin fibers. In this study, we investigate the structure and properties of recycled carbon fibers and their composites. The surface of the recycled fibers was characterized with both SEM and XPS, and the mechanical properties were characterized with single fiber tensile tests. Aligned fiber mats were processed using a centrifugal alignment technique. Alignment was characterized using image processing, and the composite mechanical properties were investigated using tensile tests. Finally, theoretical modeling of tensile strength and stiffness of composites were performed. Fiber orientation and length distributions, FOD and FLD, respectively, were taken from experimental image analysis of fiber mats and were input to the model. Effect of FOD and FLD as well as fiber-matrix shear strength were investigated. The modeling provided crucial information that can be used to guide the design of the recycled fiber composites

Computational genomics of hyperthermophiles

With the ever increasing number of completely sequenced prokaryotic genomes and the subsequent use of functional genomics tools, e.g. DNA microarray and proteomics, computational data analysis and the integration of microbial and molecular data is inevitable. This thesis describes the computational analyses on (hyper)thermophilic archaeal and bacterial genomes with a particular emphasis on carbohydrate metabolic pathways and their regulation. These analyses were integrated with wet-lab functional genomics data and results from classical molecular biology and microbial physiology experiments. The research was conducted on the archaea Sulfolobus solfataricus, Pyrococcus furiosus, T. kodakaraensis and the hydrogen producing bacterium Caldicellulosiruptor saccharolyticus. The reconstruction of the central carbohydrate metabolism in the thermo-acidophile S. solfataricus was carried out by a combination of genome sequence, whole transcriptome and proteome analyses. Only slight differences in the mRNA and the protein expression levels were shown when S. solfataricus was grown on peptides vs. glucose. However, the breakdown of D-arabinose vs. D-glucose revealed a complete novel pathway in the domain of Archaea. Similar catabolic pathways were identified in other prokaryotes and therefore a comprehensive genomic reconstruction was carried out on the pentose utilizing pathways in Archaea and, additionally, the results were compared to Bacteria and Eukarya. A computational promoter analysis of the glycolytic genes in the anaerobic species of the order Thermococcales (P. furiosus and T. kodakaraensis) indicated a clear cis-regulatory element that putatively controls all the genes of the glucose and starch degrading pathways. A comparative genomic analysis of the hyperthermophilic Thermococcales species led to the discovery of a putative transcriptional regulator that is probably involved in regulation of the entire regulon. The complete genome sequence of the extremely thermophilic Caldicellulosiruptor saccharolyticus revealed a circular genome of 2,970,275 base pairs that encodes 2679 putative proteins. The central carbohydrate pathways of C. saccharolyticus were studied in detail and the pathways for producing biohydrogen from plant cell wall material were unraveled. Subsequently, a whole transcriptome analysis of C. saccharolyticus grown on different monosaccharides showed a tight transcriptional regulation of these pathways, without glucose-based catabolite repression. C. saccharolyticus is therefore a good candidate to produce molecular hydrogen from biomass feedstock. The new insights into how prokaryotic genomes, genes and their encoded proteins function, as described in this thesis, can be applied on hyperthermophilic proteins and strains for use in and improvement of industrial processes. <br/

Senior Recital:Jill Van De Werken, Flute

Kemp Recital Hall Saturday Afternoon November 13, 2004 4:00p.m

Epigenetics and chromosome segregation in human pre-implantation embryos

Abstract Chapter 1 Currently, the average pregnancy rate per embryo transfer after in vitro fertilization (IVF) is around 32%. In order to achieve better results in the future, we need to gain knowledge on all aspects of the treatment, including pre-implantation embryo development. In this thesis, we describe the research we performed into epigenetics and chromosome segregation in human pre-implantation embryos derived from IVF. The term ‘epigenetics’ refers to heritable marks on the genome, such as DNA methylation and histone modifications. These marks are essential for chromosome structure, chromosome segregation and gene expression. Chromosome segregation is the process in which duplicated chromosomes are equally separated over two cells during cell division. Chromosomal abnormalities are detected at high frequencies in human pre-implantation embryos. This suggests that mechanisms regulating chromosome segregation are less functional during the first cell divisions of an embryo. Next to that, epigenetic marks, which are also important for correct chromosome segregation, are different in oocytes and spermatozoa and need to be re-established in early embryos. The research described in this thesis aimed to investigate both the mechanisms regulation chromosome segregation and the re-establishmen

De bijdrage van toevoeging van cacao aan tabak aan rookverslaving

In this report the effect of these compounds on the addiction to cigarette smoking was assessed, using currently available information in the literature on psychoactive compounds of cocoa. The investigated psychoactive cocoa compounds were theobromine, caffeine, serotonin, histamine, tryptophan, tryptamine, tyramine, phenylethylamine, octopamine and anandamide. The general conclusion is that the level of these compounds in added cocoa in cigarettes is not sufficient to increase the addiction to cigarette smoking.In dit rapport wordt de mogelijke bijdrage van cacao aan rookverslaving beschreven. Cacao wordt aan tabak toegevoegd om de smaak te verbeteren. Daarnaast bevat cacao tal van psychoactieve stoffen die mogelijk bijdragen aan rookverslaving Dit literatuuronderzoek beschrijft de blootstelling, farmacologie, farmacokinetiek, toxicologie, interacties en verslavende eigenschappen van de tien meest bekende stoffen in cacao. De onderzochte stoffen zijn theobromine, caffeine, serotonine, histamine, tryptofaan, tryptamine, tyramine, fenylethylamine, octopamine en anandamide. Deze stoffen komen ook via dranken en voedsel het lichaam binnen of worden door het lichaam zelf aangemaakt. Dit rapport laat zien dat de aan roken gerelateerde blootstelling aan de psychoactieve stoffen uit cacao gering is ten opzichte van de inname via voeding en dranken en/of de lichaamseigen productie van deze stoffen. Een systemisch effect lijkt derhalve onwaarschijnlijk ook al omdat lichaamseigen stoffen snel worden afgebroken. Daarnaast kunnen deze stoffen, omdat ze geinhaleerd worden, een direct effect op de luchtwegen hebben. Daarmee zou de opname van nicotine beinvloed kunnen worden. De nicotine opname zou bijvoorbeeld kunnen toenemen via luchtwegverwijding door theobromine en cafe6ne of kunnen afnemen door luchtwegvernauwing door histamine. Dit rapport laat zien dat de aan roken gerelateerde blootstelling aan deze stoffen waarschijnlijk te gering is voor een direct effect op de luchtwegen. Verder dient te worden opgemerkt dat de hoeveelheid tryptamine, tyramine en fenylethylamine die via cacao wordt toegevoegd verwaarloosbaar is ten opzichte van de hoeveelheid die in tabak zelf aanwezig is. Tot slot is aandacht besteed aan de verbrandingsproducten van cacao. Amine verbindingen als serotonin, tryptofaan, tyramine, tryptamine en fenylethylamine vormen tijdens het roken stoffen die het enzym mono amine oxidase (MAO) remmen. MAO-remmers hebben een anti-depressieve werking en kunnen op die manier bijdragen aan rookverslaving. De conclusie van dit literatuur onderzoek is dat de afzonderlijke psychoactieve stoffen in tabak als gevolg van toevoeging van cacao niet direct bijdragen aan rookverslaving. De verbrandingsproducten van cacao doen dit, via remming van het enzym mono amine oxidase, mogelijk wel. Ook de smaak van cacao wordt geassocieerd met verslaving. De literatuur biedt geen inzicht in het effect op gezondheid en verslaving van het inhaleren van de combinatie van de 10 onderzochte stoffen uit cacao