Isolation, selection and production of vesicular-arbuscular mycorrhizal fungi (VAMF) and their application in mixed cropping systems.

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Isolation, selection and production of vesicular-arbuscular mycorrhizal fungi (VAMF) and their application in mixed cropping systems.

The introduction of VAMF into agricultural systems benefits the growth and the health of the crops, especially in abandoned areas with poor soils. As a pre-requisite for the application of the symbiots, the fungi must be isolate and selected with respect to their efficiency for the plants and their adaptability to the environmental conditions in the field. Different methods of isolation and the selection procedure are described. The mass production of the selected fungi can be carried out in the greenhouse or in the field. The inoculation of the plants with the VAMF is possible in the nurseries as well as in the field. Two methods of application - inoculation of the plants with a homogenous mixture of the inoculum in the substrate and with a concentrated inoculum layer respectively - are presented

Oxidação da pirita e seus efeitos em argamassas de cimento Portland sujeitas ao ataque por sulfatos de origem interna

RESUMO O ataque por sulfatos de origem interna é resultante da reação química entre os íons Fe2+ e SO4 2-, provenientes da oxidação de agregados sulfetados, e os compostos da pasta cimentícia, e tende a promover a degradação do concreto devido formação de produtos expansivos que geram fissuração e desagregação do material. Neste trabalho, a morfologia da pirita, presente em alguns tipos de agregado, foi avaliada. O mineral foi utilizado em substituição parcial à areia (10%, em massa) na dosagem de argamassas, para estudo das modificações microestruturais e da variação dimensional linear sob envelhecimento natural durante 42 dias. A caracterização microestrutural foi executada em equipamento FEG/SEM com sonda analítica de EDS. Verificou-se, na superfície da pirita oxidada, a formação de óxidos de ferro, os quais afetaram a interface entre a pasta de cimento e o agregado nos materiais produzidos com a pirita. Quanto a variação dimensional, a argamassa apresentou apenas contrações durante o período de estudo. Verificou-se a ocorrência de fissuração e a predominância na formação de cristais aciculares de etringita aos 42 dias enquanto aos 90 dias a presença de gipsita predomina. Óxidos de ferro oriundos da oxidação da pirita são evidentes nas argamassas aos 90 dias

Report on optimum set-up for a LIBS system for applicationon on site (Laser Induced Breakdown Spectroscopy) : Sustainable Bridges Background document SB 3.12

In this report, the principal applicability of LIBS (Laser Induced Breakdown Spectroscop) for the quantitative determination of Chloride contents in concrete has been shown by preliminary results obtained on reference samples and concrete cores originating from real, contaminated sites.The physical background, the necessary components for a LIBS experiment and the measurement procedure are described. A suitable Chlorine spectral line is found at 837,6 nm. Linear calibration curves are obtained for reference samples made of cement and cementmortar with Chloride concentrations ranging between 0 wt% Cl up to 2,34 wt% Cl related to the total mass of the sample. LIBS results of concrete cores are in good agreement with chemical analysis. Further spectral lines in the investigated wave length region allow advanced interpretation of the measured data. The ratio of the intensity of the Calcium spectral line at at 849,9 nm and the Oxygen spectral line at 844,6 nm (Ca/O-ratio) is used for assignment of spectra to cement paste or aggregate, respectively. Therefore, both, the Chlorine content related to cementand the Chlorine content related to concrete is available. The laser must provide enough energy, at least 200 mJ/pulse, to create a plasma on concrete. The other laser parameters are not so crucial, so that a usual NdYAG laser with about 10 ns pulse duration, 1064 nm wave length and about 10 Hz repetition frequency is sufficient. Additionally the laser should have a compact geometry and low weight, no need for external water circulation and capable of normal power supplies. It should be robust against dust and impacts. Lasers with these specifications are commercially available and the laser in the BAM laboratory is suitable for on-site application.EC Sixth Framework ProgramSustainable Bridges – Assessment for Future Traffic Demands and Longer LivesTIP3-CT-2003-001653</p

H.: Structural investigation of concrete and masonry structures behind plaster by means of pulse phase thermography

Abstract For non-destructive testing in civil engineering, the application of infrared thermography and especially active approaches as pulse phase thermography have gained more and more importance. Pulse phase thermography is very well suite for the detection of voids and inhomogeneities close to the surface (up to a depth of 10 cm) which will be demonstrated in this paper. This method is based on pulse heating of the object under test and on the observation of the cooling down process with an infrared camera. The transient behaviour is afterwards analysed by Fast Fourier Transformation, yielding phase and amplitude images with enhanced visualisation of the defects. Results of European and National (DFG) funded projects are presented