100 research outputs found

    Application of Polypropylene Fibrillated Fibres for Reinforcement of Concrete and Cement Mortars

    Get PDF
    Polypropylene fibres have been applied for reinforcement of cement mortars and concrete for many years. The fibres restrict crack propagation and positively affect several concrete parameters. To improve the adhesion of polypropylene to cement matrix, geometrically deformed or modified fibres are commonly used. Good results are obtained by application of fibrillated fibres with the net-like structure obtained from the polypropylene types. The fibrillated polypropylene fibres were produced. The fibres were chopped to specified lengths and used for the reinforcement of concrete and cement mortars. The parameters of fresh concrete and mechanical parameters of reinforced concrete and mortar were determined. It was stated that the fibres do not affect the compressive strength of the reinforced concrete and mortar. The beneficial effect of fibres on the compressive strength of concrete is revealed after freezing and thawing cycles. The fibres influence the bending strength of the mortars. For mortars reinforced with fibrillated fibres a significant increase in the bending strength is observed. The increase in the bending strength results from enhanced interfacial adhesion and mechanical anchoring, which results from opening of the network structure and splitting of fibrillated fibres

    Structure of Polypropylene Fibres Coloured with Organic Pigments

    Get PDF

    Biodegradation of Sheep Wool Geotextiles Designed for Erosion Control

    Get PDF
    Wool geotextiles were formed from the meandrically arranged thick ropes and used as erosion control products. The geotextiles were installed in the experimental sites to protect the endangered slopes and the bank of ditches. Additionally, as a reinforcement of the soil, loose wool fibres were applied. The progress of wool biodegradation on the slope was investigated. Changes in the outer appearance, mechanical parameters, molecular structure and fibre morphology were analysed. Moreover, the nitrogen content in the soil and the effect of compounds released into soil on the grass growth were studied. The measurements revealed that the biodegradation starts at the cleavage of disulphide bonds, followed by disruption of the peptide bonds. Degradation is initiated in the outer cuticle and is followed by the decomposition of the inner cortical cells. During biodegradation, the nitrogen-rich compounds are released. The compounds act as an effective fertiliser which supports the growth of grass and significantly accelerates the greening of the slope

    Fundusze celowe jako źródła finansowania aktywizacji gospodarczej mikroregionów

    Get PDF
    Destina ted funds were an important source and often the only available one of financing productive and non-productive projects. In the material production they were used to finance the construction of new manufacturing enterprises and service workshops, to buy agricultural machinery and tractors, to rebuild roads etc; The expenditure on non-productive projects covered those of developing tourist bases and playgrounds, of building health service centres, of fitting out sanitation stations and delivery rooms, etc.Digitalizacja i deponowanie archiwalnych zeszytów RPEiS sfinansowane przez MNiSW w ramach realizacji umowy nr 541/P-DUN/201

    Concept of Inverted Refractive-Index-Contrast Grating Mirror and Exemplary Fabrication by 3D Microprinting

    Full text link
    Highly reflective mirrors are indispensable components in a variety of state-of-the-art photonic devices. Typically used, bulky, multi-layered distributed Bragg (DBR) reflectors are limited to lattice-matched semiconductors or nonconductive dielectrics. Here, we introduce an inverted refractive-index-contrast grating (ICG), as compact, single layer alternative to DBR. In the ICG, a subwavelength one-dimensional grating made of a low refractive index material is implemented on a high refractive index cladding. Our numerical simulations show that the ICG provides nearly total optical power reflectance for the light incident from the side of the cladding whenever the refractive index of the grating exceeds 1.75, irrespective of the refractive index of the cladding. Additionally, the ICG enables polarization discrimination and phase tuning of the reflected and transmitted light, the property not achievable with the DBR. We experimentally demonstrate a proof-of-concept ICG fabricated according to the proposed design, using the technique of 3D microprinting in which thin stripes of IP-Dip photoresist are deposited on a Si cladding. This one-step method avoids laborious and often destructive etching-based procedures for grating structuration, making it possible to implement the grating on any arbitrary cladding material

    Genome-Wide Association Study of Genetic Control of Seed Fatty Acid Biosynthesis in Brassica napus

    Get PDF
    Fatty acids and their composition in seeds determine oil value for nutritional or industrial purposes and also affect seed germination as well as seedling establishment. To better understand the genetic basis of seed fatty acid biosynthesis in oilseed rape (Brassica napus L.) we applied a genome-wide association study, using 91,205 single nucleotide polymorphisms (SNPs) characterized across a mapping population with high-resolution skimgenotyping by sequencing (SkimGBS). We identified a cluster of loci on chromosome A05 associated with oleic and linoleic seed fatty acids. The delineated genomic region contained orthologs of the Arabidopsis thaliana genes known to play a role in regulation of seed fatty acid biosynthesis such as Fatty acyl-ACP thioesterase B (FATB) and Fatty Acid Desaturase (FAD5). This approach allowed us to identify potential functional genes regulating fatty acid composition in this important oil producing crop and demonstrates that this approach can be used as a powerful tool for dissecting complex traits for B. napus improvement programs

    The use of Molecular Markers to Determine Wheat Lines with Chasmogamic Type of Flowering

    Get PDF
    Results of the genetic distance between two cultivars and seven lines of spring wheat are presented. Another objective of the presented paper was to find an amplification product that could be a marker of a faster growth stage and of the type of flowering. Random amplified polymorphic DNA (RAPD) was used in the studies. Forty selected primers were tested. Fourteen primers were used to develop a dendrogram presenting similarities among the cultivars and lines. Numerical analysis showed two similarity groups. The first group included KOH 5560, KOH 5637, KOH 5674, KOH 5884, KOH 5930 as well as ‚Nawara’ and ‚Zadra’. The second group consisted of: KOH 5561 and KOH 5718. Results showed the presence of some specific amplification products: OPA 09f, OPF 13k, OPF 14j, OPC 11k in wheat lines KOH 5884 and partially in KOH 5561 which indicate a fast rate of growth and chasmogamic type of flowering

    The Pastoralism in the Silesian Beskids (South Poland): In the Past and Today

    Get PDF
    The Silesian Beskids (Poland), the westernmost part of the Carpathian Mountains is an area with long pastoral tradition. For centuries sheep grazed in clearings located among forested ridges have been an integral part of the mountain landscape and pastoral customs have become essential elements of regional cultural heritage. In the chapter, the history and the current state of pastoralism in the Silesian Beskids are presented. The specific pastoral system developed in the region, based on annual migration of flocks between summer highland and winter lowland pastures is described. Local breeds and specific regional sheep products are depicted. Furthermore, the importance of pastoralism for the environment, landscape and plant biodiversity is analysed and efforts to recover sheep grazing in the mountains after a period of a deep recession caused by social and economic transitions connected with the collapse of the communist system are presented. The approach to restoration of pastoralism is illustrated using a case study of a pastoral centre which combines traditional sheep grazing with cheese production, education and several activities to promote pastoral tradition
    corecore