13,779 research outputs found
Versuche zur asymmetrischen Redox-Disproportionierung von meso-Peroxiden. Neue Chrom(III)-und Organokatalysatoren für die asymmetrische Hetero-Diels-Alder Reaktion
Polymerizable ultraviolet stabilizers for outdoor use
Polymeric materials that are stable enough to use outdoors without changes in excess of 20 years are investigated. Ultraviolet stabilizers or plastic materials were synthesized, polymerizable ultraviolet stabilizers, particularly of the 2(2-hydroxyphenyl)2H-benzotriazole family were prepared their polymerization, copolymerization and grafting onto other polymers were demonstrated, and ultraviolet stabilizing systems were devised. These materials were evaluated from the photophysical point of view
The Potential Use of Organically Grown Dye Plants in the Organic Textile Industry: Experiences and Results on Cultivation and Yields of Dyers Chamomile (Anthemis tinctoria L.), Dyers Knotweed (Polygonum tinctorium Ait.) and Weld (Reseda luteola L.)
The organic cultivation of dye plants for the certified natural textiles industry is an emerging and promising sector of organic farming. In 1999 a field trial was done with different provenances of Dyer’s Chamomile (Anthemis tinctoria L.), Dyer’s Knotweed Polygonum tinctorium Ait.), and Weld (Reseda luteola L.) on two organic farms in Lower Austria. Yields, dyestuff content, and quality parameters were analyzed. Dry matter yields of Weld ranged between 0.7 and 2.7 t ha-1, of Dyer’s Chamomile (flower heads) between 1.1 and 1.8 t ha-1. Significant differences were found between seed Weld provenances as well as between those of Dyer’s Chamomile. The total leaf dry matter of Dyer’s Knotweed (2 cuts) ranged at both sites on average 3.1 t ha-1. Seed provenances did not show differences. The total flavonoid content of Weld ranged between 1.53 and 4.00%, of Dyer’s Chamomile between 0.84 and 1.5%. The content of indican in Dyer’s Knotweed ranged between 0.50 and 1.45% of leaf dry matter, the calculated theoretical content of indigo ranged between 0.22 and 0.64% of leaf dry matter. The general use fastness properties differ according to species and provenance. Both high and low values were achieved. The data on the cultivation of dye plants in organic farming show promising results. Research should address improvement in yields and quality, development of dyestuff extracts, and optimization of dyeing methods. Research on dye plants needs a systemic look at the whole chain including producers, processors, trade,
and consumers
Stabilized unsaturated polyesters
An unsaturated polyester, such as propylene glycolmaleic acid phthalic acid prepolymer dissolved in styrene is interpolymerized with an ultraviolet absorber and/or an antioxidant. The unsaturated chain may be filled with H or lower alkyl such as methyl and tertiary alkyl such as tertiary butyl. A polymer stable to exposure to the outdoors without degradation by ultraviolet radiation, thermal and/or photooxidation is formed
Tradition, Dynamics and Sustainability of Plant Species Composition and Management in Homegardens on Organic and Non-Organic Small Scale Farms in Alpine Eastern Tyrol, Austria
In Eastern Tyrol (Austria), homegardens are an integral part of the farming system. The aim of this paper is to present evidence for the development of gardening in the study area and to identify differences/similarities between gardens at organic and non-organic farms. In 1997 and 1998, in homegardens on 91 organic and 105 non-organic farms from 12 communities, occurrence and abundance of cultivated plant species were surveyed and interviews were carried out about garden history, management and plant use. For the factor organic/non-organic, differences between gardens were statistically tested. Garden management is similar in organic/non-organic gardens, except mixed cropping and the use of alternative remedies to combat diseases, both with significantly higher occurrence on organic farms. Popular innovations from organic farming did not have a strong and clearly visible impact on management of homegardens. The population of cultivated plant species, until the 1960s approx. 51; nowadays approx. 587 species in all gardens, and main use of garden produce has been in a process of change with an increase in importance of species used as food and for decoration, but with no significant differences concerning organic/non-organic. Women farmers gardening in Eastern Tyrol are highly sympathetic to the principles of organic farming, even on non-organic farms. Sustainability can be increased when methods from organic gardening are promoted and tested locally more effectively. Science and policy should recognize the work of women farmers who maintain homegardens with high agrobiodiversity as part of their culture
Stop Co-Annihilation in the Minimal Supersymmetric Standard Model Revisited
We re-examine the stop co-annihilation scenario of the Minimal Supersymmetric Standard Model, wherein a bino-like lightest supersymmetric particle has a thermal relic density set by co-annihilations with a scalar partner of the top quark in the early universe. We concentrate on the case where only the top partner sector is relevant for the cosmology, and other particles are heavy. We discuss the cosmology with focus on low energy parameters and an emphasis on the implications of the measured Higgs boson mass and its properties. We find that the irreducible direct detection signal correlated with this cosmology is generically well below projected experimental sensitivity, and in most cases lies below the neutrino background. A larger, detectable, direct detection rate is possible, but is unrelated to the co-annihilation cosmology. LHC searches for compressed spectra are crucial for probing this scenario
Urban Organic Farming in Austria with the concept of Selbsternte ("self -harvest"): An agronomic and socio-economic analysis
In Vienna, consultants, organic farmers and green-minded consumers have developed a new concept of urban organic farming, called Selbsternte (`self-harvest'). Organic farmers prepare a plot of arable land (the Selbsternte plot) and sow or plant rows composed of 18-23 plant species. In mid-May the plots are divided into subplots that contain 2-6m of
every sown species and are rented to so-called self-harvesters for a period of about 136 days. In 2002 Selbsternte was being practiced at 15 plots in Vienna or in neighboring cities, represented by 861 subplots, with a total area of 68,740m2, and managed by 12 organic farmers for 861 registered self-harvesters. At the Roter Berg plot, experimental subplots were established to evaluate yields and the value of the harvested produce, and interviews were conducted with 27 self-harvesters, the eight Selbsternte farmers and one Selbsternte consultant. The experimental subplots were managed in two different ways, namely, `with low intensity' (LIS) and `with high intensity' (HIS; meaning additional harrowing, mulching and sowing of additional plants). At the LIS 24.2 h and at the HIS 38.9 h of work were invested over 51 days. Monetary investment was US259 for the HIS subplots. The total harvest of fresh produce was: 163 kg/subplot for LIS and 208 kg/subplot for HIS subplots. The total value of the harvest at the HIS was US766 for organic prices. All self- arvesters saw the rental of a subplot and the work as an activity of leisure. More than half of the self-harvesters reported `trying something new' at their subplots. The most frequently mentioned innovation for them was growing an unknown species. Twenty-five self-harvesters sowed 54 different, additional plant species. The motivating factors in establishing Selbsternte plots, as reported by all the farmers, were, primarily, better relations with consumers and work diversifcation, and only then were economic factors a consideration. The contribution of Selbsternte to income varied at the farms, being between 0 and 30% of the total farm income. As a main success factor, all of the farmers reported a close relationship between the self-harvesters and the farmers. Selbsternte subplots can be understood as small experimental stations where self-harvesters merge traditional horticultural techniques with urban ideas on permaculture, sustainable land use and participatory farming. Selbsternte has potential value for the improvement of urban agriculture, but also for the development of organic farming in general
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