173 research outputs found
The mineralization of commercial organic fertilizers at 8°C temperature
In organic production only organic fertilizers and soil conditioners can be used to supply
the soil with nitrogen. The mineralization of these products is slow and so there can be
problems with the supply of nitrogen, when the demand of the plants is high. The supply of
nitrogen from organic products depends on the speed of their mineralization which is
primarily influenced by the composition and formulation of their raw material.
In apple production in the Alps-region especially during spring problems with nitrogen
supply are common. In that period, the weather conditions are sometimes bad, the
temperature in the soil is low and mineralization starts slowly - apple trees demand more
nitrogen than the soil can deliver.
To compensate the demand of the apple tree organic growers can not use mineral
fertilizers but only organic fertilizers and soil conditioners whose mineralization rate is often
unknown. There is a strong need in organic fruit production to receive more information
about the behaviour of fertilizers in the soil especially concerning their N-release under
different conditions.
To acquire that information, incubation experiments under controlled conditions
(temperature, type of soil, humidity of the soil) were carried out in the laboratory to
determine the mineralization-rate of different organic fertilizers and soil conditioners which
are available in our region
Influence of the characteristics of isolation and mitigation devices on the response of single-degree-of-freedom vibro-impact systems with two-sided bumpers and gaps via shaking table tests
During strong earthquakes, structural pounding may occur between structures (buildings, bridges, strategic facilities, critical equipment, etc.) and the surrounding moat wall because of the limited separation distance and the deformations of the isolator. An arrangement that favors the solution of this problem is the interposition of shock absorbers. Thus, the influence of geometrical and mechanical characteristics of isolation and mitigation devices on nonlinear, nonsmooth response of vibro-impact systems is experimentally investigated in this paper on the basis of a laboratory campaign of experimental tests. Shaking table tests were carried out under a harmonic excitation in order to investigate two different configurations: the absence and the presence of bumpers. Three different values of the table acceleration peak were applied, four different amplitude values of the total gap between mass and bumpers were considered, and also four different types of bumpers were employed; moreover, two problems were addressed, namely, control of excessive displacements and control of excessive accelerations, and hence, two types of normalization were adopted in order to better interpret experimental results. Suitable choices of pairs of bumpers and gaps were suggested as a trade-off between conflicting objectives. Furthermore, a numerical model was proposed, and its governing parameters identified in order to simulate the experimental results
Scenarios in the experimental response of a vibro-impact single-degree-of-freedom system and numerical simulations
In this paper, possible scenarios within the experimental dynamic response of a vibro-impact single-degree-of-freedom system, symmetrically constrained by deformable and dissipative bumpers, were identified and described. The different scenarios were obtained varying selected parameters, namely peak table acceleration A , amplitude of the total gap between mass and bumpers G and bumper’s stiffness B. Subsequently, using a Simplified Nonlinear Model results in good agreement with the experimental outcomes were obtained, although the model includes only the nonlinearities due to clearance existence and impact occurrence. Further numerical analysis highlighted other scenarios that can be obtained for values of the parameters not considered in the experimental laboratory campaign. Finally, to attempt a generalization of the results, suitable dimensionless parameters were introduced
Are higher-gradient models also capable of predicting mechanical behavior in the case of wide-knit pantographic structures?
The central theme of this study is to investigate a remarkable capability of a second-gradient continuum model developed for pantographic structures. The model is applied to a particular type of this metamaterial, namely the wide-knit pantograph. As this type of structure has low fiber density, the applicability of such a continuum model may be questionable. To address this uncertainty, numerical simulations are conducted to analyze the behavior of a wide-knit pantographic structure, and the predicted results are compared with those measured experimentally under bias extension testing. The results presented in this study show that the numerical predictions and experimental measurements are in good agreement; therefore, in some useful circumstances, this model is applicable for the analysis of wide-knit pantographic structures
Protein interactions in enzymatic processes in textiles
Enzymes are the catalysts of all reactions in living systems. These reactions are catalysed in the active sites of globular proteins. The proteins are composed by amino acids with a variety of side chains ranging from non-polar aliphatic and aromatic to acidic, basic and
neutral polar. This fact allows to a globular 3D protein to create in the active site all ranges of
microenvironments for catalysis. Major advances in microbial technology and genetics allow recently the broad range of enzymatic applications in the industry.
Enzymatic processes have been increasingly
incorporated in textiles over the last years. Cotton, wool, flax or starches are natural materials used in textiles that can be processed with enzymes. Enzymes have been used for desizing, scouring, polishing, washing, degumming, peroxide degradation in bleaching baths as well as for decolourisation of dyehouse wastewaters, bleaching of released dyestuff and inhibiting dye transfer. Furthermore many new applications are under
development such as natural and synthetic fibres modification, enzymatic dyeing, finishing etc. Most of the textile processes are heterogeneous where an auxiliary as a dye, enzyme, softener or oxidant have to
be taken from the solution to the fibre. These processes require the presence of surface-active agents, ionic force “balancers”, buffers, stabilisers and others, and are
characterized with high turbulence and mechanical agitation in the textile baths. In this paper it is intended to understand and discuss the major protein interactions within textile processes and to try to anticipate troubleshooting possibilities when enzymes
are used. It can be expected that an enzyme protein can interact with all chemical agents in solution due to the large variety of side chains of the outer-amino-acids in the large 3D structure of the protein. Without the aim of
being exhaustive various points will be discussed where protein interactions are important for textile processing
Pretreatment of cotton spinning residues for optimal enzymatic hydrolysis: a case study using green solvents
ABSTRACT: The effectiveness of imidazole and ionic liquid pretreatments for the conversion of cotton spinning residues (dirty cotton residue - DCR and cotton filter powder - CFP) into soluble sugars was investigated. DCR was pretreated with imidazole using temperatures and reaction times that were arranged in a 2(2) factorial design and pretreatment performance was evaluated by enzymatic hydrolysis. High glucan to glucose and xylan to xylose yields (78.0 and 94.9 mol %) were obtained from the solids produced at 140 degrees C and 2h (center point), which provided delignification levels of 45.5% (w.v(-1)). The same pretreatment condition was applied to CFP yielding only 16.0% (w.v(-1)) of delignification, but 75.8 mol % of glucan and 95.7 mol % of xylan were converted as their corresponding monomeric sugars after enzymatic hydrolysis. Both pretreated materials were subjected to a central composite design to find the best enzymatic hydrolysis conditions regarding substrate total solids (TS) and enzyme loading. More than 40 g.L-1 glucose was obtained from both pretreated materials at 13.7% w.w(-1) TS and 20 FPU.g(-1) glucan after 96 h of hydrolysis. Ionic liquid pretreatment of the same cotton spinning residues showed moderate delignification levels, accompanied by a change in biomass crystallinity from cellulose 1 beta to cellulose II. This turned to be very important to improve enzymatic hydrolysis yields. Therefore, biomass delignification and crystallinity confirmed to be key factors governing the enzymatic saccharification of cotton spinning residues.info:eu-repo/semantics/publishedVersio
The mineralization of commercial organic fertilizers at 8°C temperature
Abstract In organic production only organic fertilizers and soil conditioners can be used to supply the soil with nitrogen
Mandatory Disclosure about Environmental and Employee Matters in the Reports of Italian-Listed Corporate Groups
This paper analyses the impact of Italian Legislative Decree 32/2007 – following the 2003/51 European Directive – and the disclosure of environmental and employee matters in terms of overall volume, completeness of information, presence of bad/good news and target-oriented information. Content analysis has been applied to all Italian corporate groups that made public both the consolidated annual report and the stand-alone social and environmental report in 2005 and in 2010, for a total of 96 reports. The results show that despite the overall increase in sentences devoted to environmental and employee matters, the completeness of the information has not substantially improved, indicating that the 2007 regulation has been ineffective. The Italian experience could provide useful insights for European regulators. Such insights may inform policy recommendations to design a mandated social and environmental accountability process with the potential of providing information to societal stakeholders while facilitating accountability
Specificities of a chemically modified laccase from trametes hirsuta on soluble and cellulose-bound substrates
Laccases could prevent fabrics and
garments from re-deposition of dyes during
washing and finishing processes by degrading the solubilized dye. However, laccase action must be restricted to solubilized dye molecules thereby
avoiding decolorization of fabrics. Chemical
modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. Polyethylene glycol (PEG) was covalently attached onto a laccase from Trametes hirsuta. Different molecular
weights of the synthetic polymer were tested
in terms of adsorption behaviour and retained
laccase activity. Covalent attachment of PEG
onto the laccase resulted in enhanced enzyme
stability while with increasing molecular weight of attached PEG the substrate affinity for the laccase conjugate decreased. The activity of the modified laccases on fibre bound dye was drastically reduced decreasing the adsorption of the enzyme on various fabrics. Compared to the 5 kDa PEG laccase conjugate (K/S value 47.60
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