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Natural fibers have the potential to replace glass fibers in fiber-reinforced composite applications. However, the natural fibers’ intrinsic properties cause these issues: 1) the mechanical property variation; 2) moisture uptake by natural fibers and their composites; 3) lack of sound, cost-effective, environmentriendly fiber-matrix compounding processes; 4) incompatibility between natural fibers and polymer matrices; and 5) low heat-resistance of natural fibers and their composites. This dissertation systematically studied the use of kenaf bast fiber bundles, obtained via a mechanical retting method, as a light-weight reinforcement material for fiber-reinforced thermoset polymer composites for automotive applications. Kenaf bast fiber bundle tensile properties were tested, and the effects of locations in the kenaf plant, loading rates, retting methods, and high temperature treatments and their durations on kenaf bast fiber bundle tensile properties were evaluated. A process has been developed for fabricating high fiber loading kenaf bast fiber bundle-reinforced unsaturated polyester composites. The generated composites possessed high elastic moduli and their tensile strengths were close to specification requirements for glass fiber-reinforced sheet molding compounds. Effects of fiber loadings and lengths on resultant composite’s tensile properties were evaluated. Fiber loadings were very important for composite tensile modulus. Both fiber loadings and fiber lengths were important for composite tensile strengths. The distributions of composite tensile, flexural and impact strengths were analyzed. The 2-parameter Weibull model was found to be the most appropriate for describing the composite strength distributions and provided the most conservative design values. Kenaf-reinforced unsaturated polyester composites were also proved to be more cost-effective than glass fiber-reinforced SMCs at high fiber loadings. Kenaf bast fiber bundle-reinforced composite’s water absorption properties were tested. Surface-coating and edge-sealing significantly reduced composite water resistance properties. Encapsulation was a practical method to improve composite water resistance properties. The molding pressure and styrene concentrations on composite and matrix properties were evaluated. Laser and plasma treatment improved fiber-to-matrix adhesion.

The electromagnetic shielding effectiveness of kenaf bast fiber based composites with different iron oxide impregnation levels was investigated. The kenaf fibers were retted to remove the lignin and extractives from the pores in fibers, and then magnetized. Using the unsaturated polyester and the magnetized fibers, kenaf fiber based composites were manufactured by compression molding process. The transmission energies of the composites were characterized when the composite samples were exposed under the irradiation of electromagnetic (EM) wave with a changing frequency from 9 GHz to 11 GHz. Using the scanning electron microscope (SEM), the iron oxide nanoparticles were observed on the surfaces and inside the micropore structures of single fibers. The SEM images revealed that the composite’s EM shielding effectiveness was increased due to the adhesion of the iron oxide crystals to the kenaf fiber surfaces. As the Fe content increased from 0% to 6.8%, 15.9% and 18.0%, the total surface free energy of kenaf fibers with magnetizing treat increased from 44.77 mJ/m2 to 46.07 mJ/m2, 48.78 mJ/m2 and 53.02 mJ/m2, respectively, while the modulus of elasticity (MOE) reduced from 2,875 MPa to 2,729 MPa, 2,487 MPa and 2,007 MPa, respectively. Meanwhile, the shielding effectiveness was increased from 30-50% to 60-70%, 65-75% and 70-80%, respectively.

Flax is often considered a total utilization crop because of the potential to extract value from two distinct products - seeds and stem fibres. However, very little genetic information is available on flax fibre genetics in comparison to oil improvement studies. In order to gain a detailed understanding of genetic control of the fibre concentration and search for the possibilities of developing dual purpose flax lines using both seed oil and stem fibre, the following studies were initiated: The first study evaluated the fibre and oil-related traits in a recombinant inbred population derived from a cross between a fibre flax variety Viking and an oilseed flax genotype E1747 over multiple locations under western Canadian field conditions. The study confirmed the presence of a significant genotype by environment interaction (p < 0.01) for fibre concentration indicating selection for this trait will be challenging. However, a lack of significant correlation between fibre and oilseed characteristics in field trials was encouraging and strengthened the hypothesis that breeding dual purpose flax types for western Canada is possible. The study also identified potential recombinant inbred lines (RILs) with enhanced fibre concentration as well as oil characteristics for use in future breeding endeavors. The second study established an anatomical basis for further research into flax fibre improvement by studying differences between the stem anatomy of 14 diverse flax genotypes in the field and under controlled environments such as a growth chamber. The results from the study supported the use of controlled environments for the purpose of quick screening of high fibre containing genotypes, especially at the green capsule stage of plant growth. The results also indicated that it was possible to select high fibre oilseed flax lines based on anatomical markers such as average area of single fibre cells, total fibre area and fibre to stem area ratio. In the third study, 17 simple sequence repeat (SSR) and 2 cleaved amplified polymorphic sequences (CAPS) molecular markers were used to assess the extent of genetic variability in the Viking × E1747 RIL population. CAPS markers LuFAD3A and LuFAD3B had the highest marker trait association (p < 0.0001) with linoleic and linolenic acid concentration. SSR markers such as CV8824, 5B6 and LU32 were found to be associated with plant height, oil concentration and protein concentration respectively using single marker analysis and step wise regression analysis. The molecular study confirmed the importance of Viking × E1747 mapping population in identifying genes/ markers related to both fibre and oilseed related traits in flax. In the fourth study, global transcript profiling using cDNA - based microarrays was performed to identify differentially expressed fibre related transcripts between Viking and E1747. The largest group of transcripts (7 %) found more abundant in Viking relative to E1747 fell under the functional group of cell wall development using gene ontology (GO) analysis. Transcripts such as callose synthases, expansins, cytochrome P450, fasciclin-like arabino galactan proteins and β-galactosidases were highly abundant in Viking relative to E1747. The transcripts more abundant in E1747 relative to Viking were UDP – glucose glucosyltransferase, auxin repressed protein, ubiquitin conjugating enzyme, peroxidases and lipid transfer proteins. Quantitative real time PCR results confirmed the suitability of the microarray platform to accurately discriminate transcript profiles between the two diverse flax types. In conclusion, this research has provided a number of new insights into flax fibre genetics. This information lays the foundation for further genetic studies on flax bast fibres and will complement research on developing dual purpose flax varieties.

Grewia optiva är en utav många outnyttjade stjälkfibrer som skulle kunna bidra till ökandet utav de naturliga fiberalternativen. Fibern har idag inte så många användningsområden på grund utav dess hårda och styva uppbyggnad, vilket gör den svår att spinna till garn. På uppdrag av organisationen Bhartiya Gramotthan Sanstha (BGS) har i detta projekt en redan befintlig metod utvecklats för att förädla fibern. Vad som främst eftersöktes var nedbrytandet av pektin som är en av de faktorer som bidrar till fiberns hårda och styva struktur. I metoden användes biologiskt nedbrytbara enzym som katalysatorer. En fungerande metod skulle kunna öka användningsområdet hos stjälkfibrer generellt och öka möjligheten till användandet utav fler naturliga fibrer. Enzymet som har använts i metoden är ett pektatlyas EC 4.2.2.2 som katalyserar reaktionen som sker då pektinmolekyler klyvs. För att effektivisera processen adderades en komplexbildare, EDTA, som tidigare visat goda resultat för lin. Efter enzymbehandlingen skedde en viktreduktion av fibrerna samt förändring av deras utseende. I svepelektronmikroskop observerades förändring av ytstruktur samt separation mellan fiberbuntarna. Dessa parametrar är viktiga och har stor inverkan på spinnbarheten hos fibrer. I projektet har försök att spinna fibern gjorts men inte lyckats helt. Förändringen på ytstruktur och separation mellan fibrerna tyder dock på att behandlingen är ett steg i rätt riktning. / Grewia optiva is one of many unused bast fibres that could contribute to an increase of natural textile fibres on the industrial market. This fibre has to-day not as many applications due to its stiff and hard structure that makes the fibre difficult to spin into yarn. On behalf of the organisation Bhartiya Gramotthan Sanstha (BGS) has an existing method been developed to process the Grewia optiva fibre. The method is developed to break down substances like pectin that is responsi-ble for the hard and stiff structure of the fibre. Degradable biological en-zymes were used as catalyser in the method. With a functioning method like this the applications of bast fibres could increase and contribute to the use of more natural fibres. The enzyme used to catalyse the chemical reaction and the cleavage of pec-tin molecules in this method was a pectate lyase EC 4.2.2.2. In this method EDTA was used as a chelator to efficient the chemical process. EDTA has been used as a chelator in earlier reports and showed good results. After the enzymatic treatment a weight reduction of the fibre was notable. In SEM-analysis separation between fibres and changes on the fibre surfaces was observed. These parameters are important and affect the spinning capability of the fibre. To test the spinning capability of the enzyme treated fibre they were spun in a ring spinning system, unfortunately not successfully. The surface changes and the separation shows that the enzymatic treatment had occurred and indicates that the method has developed in the right direction.

Šio darbo objektas – Juodupės pelkė, esanti Aukštaitijos nacionaliniame parke. Teritorijos, kuriai rengiamas gamtotvarkos planas, bendras plotas yra 225 ha. Didžioji dalis Juodupės pelkes BAST, patenka į ANP priklausančio Juodupės hidrografinio draustinio teritoriją. Teritorijoje aptiktos šios ES Buveinių direktyvos I priede įrašytos buveinės - 6450 Aliuvinės pievos, 7140 *Tarpinės pelkės ir liūnai, 7160 Nekalkingi šaltiniai ir šaltiniuotos pelkės, 7230 Šarmingos žemapelkės, 9010 *Vakarų taiga, 9080 Pelkėti lapuočių miškai ir 91D0 *Pelkiniai miškai. Juodupės pelkėje rasta viena į Lietuvos raudonąją knygą įrašyta augalų bendrija – liūninis viksvynas. Taip pat randamos į Buveinių direktyvos II priedą įrašytos dvi rūšys: žvilgančioji riestūnė (Hamatocaulis vernicosus) bei pelkinė uolaskėlė (Saxifraga hirculus). Randama keliolika į Lietuvos raudonąją knygą įrašytų augalų rūšių. Pagrindinės gamtotvarkos priemonės pelkinės uolaskėlės (Saxifraga hirculus) augavietėse ir europinės svarbos pelkių bei pievų buveines yra medžių, krūmų, jų atžalų šalinimas ir periodiškas šienavimas. Pagrindinės palankios teritorijos europinės svarbos miško buveinių apsaugos būklės palaikymo priemonės – miško kirtimų nevykdymas ir negyvos medienos gausinimas. / The object of this work – Juodupė bog which is in national park of Aukštaitija. Area of territory to which the management plan was prepared is 225 ha. Biggest part of Juodupė important for habitats conservation territories gets in to the area of Juodupė hydrographical reserve belonging to national park of Aukštaitija. There were found these habitats entered in to the First annex of EU Habitat directive – 6450 Northern boreal alluvial meadows, 7140 *Transition mires and quaking bogs, 7160 Fennoscandian mineral-rich springs and springfens, 7230 Alkaline fens, 9010 *Western taiga, 9080 Fennoscandian deciduous swamp woods and 91D0 *Bog woodlands. There was found one in to Lithuanian red book entered plant community. Also there were found two species entered in to Second annex of EU Habitat directive - Hamatocaulis vernicosus and Saxifraga hirculus. In this territory grows several other plant species entered in to Lithuanian red book. Main management instruments in S. hirculus growing places and other habitats are elimination of trees, bushes and their offsets and periodical haymaking. Main instruments for keeping good state of important territories for wood habitats conservation are non-compliance of tree cutting and increasing amount of dead wood.

Nowadays great attention is payed to the protection of the biodiversity not only in the EU but also in the whole world. The wane of the biodiversity was influenced by the intensive use of the natural resources and the decimation of the natural landscape. This process has become very fast and often irreversible. According to the protection of the biodiversity, the five international conventions have been signed: Ramsar Convention, Rio de Janeiro Convention, Washington Convention, Bonn Convention, Bern Convention. Lithuania has ratified all of them. Now Lithuania has a very important task to fulfil all the obligations and requirements. The most important obligation is to establish the Natura 2000 territories network. Though the requirements of the directives have been started implementing since 1999, the process still continues. The SPAs status has already been given to 77 localities and 299 are the SAC potentials. There are 12 territories that are intended for the bat protection in the SAC potentials register. Great concern has been showed to the protection of these animals in Europe. On purpose to give it a better protection 31 European countries have ratified the Agreement on the Conservation of Population of European Bats (EUROBATS). Lithuania signed it in 2001. The aim of the work is to study how successfully Lithuania deals with the main 8 obligations. The obligations are: the prohibition of the deliberate catching, keeping and killing, the protection of bats converts... [to full text]

Thesis (MTech (Design))--Cape Peninsula University of Technology, 2008 / This thesis argues that the story of hemp is one of mistaken identity and focuses on the potential of hemp (Cannabis sativa L.) in a social and economic context. It also asserts how hemp with the application of appropriate technologies can be developed nationally 'new' material, with reference to examples from abroad. The current proliferation of raw material shortages means that designers have a social responsibility to seek new ways to source and process materials for a sustainable future. Designers are the "future creators" and should prescribe materials that are not only healthy in the cycle of production, but also ensure an afterlife (recycling). The methodology employed is a combination of qualitative (such as interviews) and quantitative methods (such as statistical analysis). Life Cycle Analysis is used to study the ecological impact of substituting hemp for current materials and processes. The study interrogates the historic significance of hemp in various societies across the world with particular focus on Europe, Japan, the United States of America, Ireland and Australia. Such information is analysed within the realities of the South African context. A vast amount of information on hemp has been published but practical information is hard to obtain in South Africa necessitating a search for definite answers abroad, mainly in Europe where there is a strong development in this field. After researching the production of the hemp raw materials and the manufacture of viable hemp products abroad, lessons could be assessed for application to the local market. The findings endorse the view that hemp is a sustainable zero-waste material; the whole plant can be used when harvested, which makes it an ideal material on which to base an eco-design system. Hemp can be processed by utilizing either high technology equipment or by the use of locally available equipment and manual labour. It can be converted into a multi-diverse range of viable products such as paper, thatching, building material and ceiling panels. The main reason for the isolation of hemp in South Africa is the mistaken assumption that it is a drug and outlawed by our legislation. Since hemp (Cannabis sativa L) is perceived as a vilified cousin of marihuana it has lead to a blanket ban on both plants. This is certainly not warranted as hemp produces an extremely low value of the controversial hallucinogenic tetrahydrocannabinol (THC)properties which is negligible.

Cellulosic fibers sized from the macro-scale to the nano-scale were prepared hierarchically from kenaf bast fibers using chemicals. The process began with a hermetical alkaline retting followed by a bleaching treatment. The bleached fibers were hydrolyzed using inorganic acid, from which microfibers and cellulose nanowhiskers (CNWs) were fabricated. Inorganic nanoparticle impregnation (INI) was used to treat the retted fibers for the improvement of the interfacial compatibility between the fiber and polypropylene (PP) matrix. The retted fibers and INI-treated fibers were used as reinforcement for the PP polymer composites. Film casting process was used to make CNW/PVA composites. The hermetical retting process used in this study produced fibers with high cellulose contents (81-92%) by removing the lignin and hemicelluloses. Higher retting temperature resulted in higher fiber surface hardness and elastic moduli. The tensile strengths and tensile moduli of the fibers decreased as the temperature increased. The SEM images showed the micropores in the cell wall structure for the fibers retted at over 130°C, providing the possibility to anchor nanoparticles into the cell wall. Surface morphology of the INI-treated fibers was examined with SEM, and showed that the CaCO3 nanoparticle crystals grew onto the fiber surface. Energy-dispersive X-ray spectroscopy (EDS) was used to verify the CaCO3 particle deposits on the fiber surface. As the size scale of the fibers decreased, the fiber crystallinity increased from 49.9% (retted fibers) to 83.9% (CNWs). About 23% á-cellulose in the raw kenaf bast fibers had been converted into CNWs. The retted fibers without INI treatment had poor compatibility with the polypropylene matrix. The INI treatment improved the compatibility between the fibers and the PP matrix, resulting in an improvement in kenaf fiber/PP composite tensile moduli and tensile strengths. The CNWs prepared from kenaf bast fiber gave excellent reinforcement for PVA composites. A nine percent increase of CNWs in the CNW/PVA composites yielded significant improvements in tensile strength and modulus of about 46% and 152%, respectively, compared with pure PVA.