283 research outputs found

    Plant cover and management practices as drivers of soil quality

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    Human activities intensively modify soil properties and quality according to land-use and management practices. In Mediterranean areas, pollution and fires may directly alter some soil abiotic properties as well as the steady-state condition of soil microbiota. The aim of this study was to evaluate if the chemical and biological characteristics of two kinds of soil, Arenosols and Andosols, of a natural reserve and an urban park respectively, were affected by the same or different plant covers (trees and grasses). At each site, five sub-samples of surface soils (0–10 cm) were collected under maquis (trees) and gap of grasses. The soils were analyzed for physico-chemical parameters (organic matter and water contents, pH, C, N, Cr, Cu, Ni and Pb concentrations) and biological parameters (microbial and fungal biomass, respiration, metabolic quotient and coefficient of endogenous mineralization). The soil quality was evaluated through an integrated index, calculated taken into account all the investigated parameters. The results highlighted that soils under trees inside the urban park, with the highest amount of organic matter, showed higher microbial biomass and activity as compared to soils under grasses. The high concentration of Cu and Pb in these latter soils inhibited the microbial biomass and activity that were not exclusively affected by litter quality. Soil quality would seem to be strongly affected by the pedogenetic derivation and the management practices more than plant covers

    Consteel© EAF and conventional EAF: a comparison in maintenance practices

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    The present paper highlights the main differences between Consteel® and conventional EAF technologiesregarding scheduled and unscheduled maintenance practices. The study has been made on the basis of datacollected in plants with high maintenance standards and more than 10 years of operational experience.These data have been analyzed and organized in a comparison table where they have been associated with therelevant maintenance costs. The comparison shows that the Consteel® technology achieves a significantreduction in the overall maintenance costs compared to a conventional EAF

    Variation of the chemical and biological properties of a Technosol during seven years after a single application of compost

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    Technosols are composed of natural soils mixed with artificial materials and can be an inhospitable environment for the soil microbial community. The main goal of the current research was to evaluate temporal variations of Technosol quality through an integrated approach, considering all of the evaluated chemical, physical and biological characteristics for a period of seven years after a single application of compost. The soil samples were evaluated using the following parameters: pH; water content; water holding capacity; bulk density; porosity; organic matter and N contents; C/N ratio; fungal biomass; microbial biomass; respiration; metabolic quotient (qCO 2 ); and endogenous mineralisation coefficient (CEM). The overall evaluation showed that a single application of compost improved the soil quality in the short term. A decrease in Technosol quality over the long term appears to be due to deterioration of the physical and chemical properties, rather than a change in biological properties

    RECYCLING OF LF-WHITE SLAG

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    Over the last few years technologies of the plants dedicated to recycle of ladle slag have been improved. The type of recycling evaluated in the present study mainly consists in the reuse of the ladle slag and refractory, injecting them into the Electric Arc Furnace. The recycling of ladle slag can permit to achieve interesting advantageous results: decreasing the amount of dumped material, the cost of EAF fluxes and improve the slag foaminess

    Synthesis of dialkyl ethers by decarboxylation of dialkyl carbonates

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    The decarboxylation reaction of dialkyl carbonates to give their related ethers was investigated. The reaction was carried out at atmospheric pressure and in the presence of hydrotalcite or basic alumina as catalysts without any solvent. The influence of several reaction parameters on the selectivity was studied (e.g. temperature, amount of catalyst, substrate concentration, solvent). The stability of the catalyst was also investigated. The experimental data for the decarboxylation confirmed that this reaction is complicated by competitive processes, such as dismutation and, in one case, pyrolysis. The results obtained show that in the presence of hydrotalcite as a catalyst, symmetrical dialkyl ethers can be synthesised with yields up to 80%. Dissymmetrical ethers (i.e. methyl alkyl ethers) can be produced with yields up to 80% at high temperature (250 â—¦C). The catalyst proved to be fully recyclable in all cases studied, except for the carbonate containing n-octyl moiety

    EAF process optimization based on continuous analysis of off-gases and real-time control of chenical package parameters: the case of TAMSA

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    Techint Goodfellow Technologies (formerly Stantec) implemented their Goodfellow EFSOP™ system at Tubos de Acero de Mexico, SA (TAMSA) in late 2002. The technology was used to optimize the use of chemical energy within the electric arc furnace (EAF). The project was a success providing TAMSA a 4.4% reduction in conversion costs (oxygen, methane, electricity and carbon) and a reduction of 1 minute in power-on-time. Subsequently, in late 2003, Techint installed and commissioned their KT-Chemical package at TAMSA. The Goodfellow EFSOP™ system was again used to optimize chemical energy usage within the EAF. The Goodfellow Expert Furnace System Optimization Process (Goodfellow EFSOP™) is a proprietary process that uses continuous off-gas analysis, along with process monitoring to optimize the use of chemical energy within the electric arc furnace (EAF). Optimization is achieved by adjustments to the electric furnace process (carbon charge practice, injected carbon, methane and oxygen), according to analysis of off-gas measurements. Further benefits are provided through dynamic control of oxygen and methane in response to real-time off-gas composition. This paper details the application of the Goodfellow EFSOP™ optimization process to the KT chemical package at TAMSA and concludes with a summary of the achievements provided by the merging of these two technologies. Ultimately, a reduction in electrical energy (12.3%) and methane consumption (33%) were achieved at TAMSA. Economically, these savings outweigh the increase in total carbon usage (11%) and oxygen consumption (14.6%) and have provided an overall 2% reduction in power-on-time (1 minute), considering an increase in tapping weight by 11% (from 142 to 158) tons liquid steel. Iron oxidation has also been reduced, as indicated by slag chemistry, from over 40% initially to 32% at present. Electrode consumption has been reduced by 9%

    Impact of anthropic activities on soil quality under different land uses

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    Anthropization often leads to land use transformation, causing deep changes to soil properties and its quality. Land use change could be an environmental and socioeconomic problem, as it impacts soil quality and ecosystem services. There is an urgent need to understand the pressures affecting soil quality. The aim of the work is to quantify the impact of different land uses on soil abiotic and biotic properties and on its quality. To achieve the aims, soils from different land uses (forest, urban and agricultural) were collected in the surroundings of Naples and analyzed for pH, water content, contents of C and N, C/N ratio and total and available concentrations of Cu, Ni and Pb, microbial and fungal biomasses, basal respiration and metabolic quotient. Then, a soil quality index (SQI) was calculated for each land use. The results showed that soil abiotic and biotic properties of the agricultural sites differed from those of forest and urban sites. At agricultural sites, microbial abundances decreased due to low amount of C and N and to high amount of Cu and Pb. This caused low use efficiency of energetic substrates and a reduced soil quality of agricultural sites as compared to forest and urban sites

    HOME-BIO (sHOtgun MEtagenomic analysis of BIOlogical entities): a specific and comprehensive pipeline for metagenomic shotgun sequencing data analysis

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    Background: Next-Generation-Sequencing (NGS) enables detection of microorganisms present in biological and other matrices of various origin and nature, allowing not only the identification of known phyla and strains but also the discovery of novel ones. The large amount of metagenomic shotgun data produced by NGS require comprehensive and user-friendly pipelines for data analysis, that speed up the bioinformatics steps, relieving the users from the need to manually perform complex and time-consuming tasks. Results: We describe here HOME-BIO (sHOtgun MEtagenomic analysis of BIOlogical entities), an exhaustive pipeline for metagenomics data analysis, comprising three independent analytical modules designed for an inclusive analysis of large NGS datasets. Conclusions: HOME-BIO is a powerful and easy-to-use tool that can be run also by users with limited computational expertise. It allows in-depth analyses by removing low-complexity/ problematic reads, integrating the analytical steps that lead to a comprehensive taxonomy profile of each sample by querying different source databases, and it is customizable according to specific users’ needs

    DNA methylation dynamic of bone marrow hematopoietic stem cells after allogeneic transplantation

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    Background: Allogeneic hematopoietic stem cell transplantation (AHSCT) is a curative therapeutic approach for different hematological malignancies (HMs), and epigenetic modifications, including DNA methylation, play a role in the reconstitution of the hematopoietic system after AHSCT. This study aimed to explore global DNA methylation dynamic of bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs) from donors and their respective recipients affected by acute myeloid leukemia (AML), acute lymphoid leukemia (ALL) and Hodgkin lymphoma (HL) during the first year after transplant. Methods: We measured DNA methylation profile by Illumina HumanMethylationEPIC in BM HSPC of 10 donors (t0) and their matched recipients at different time points after AHSCT, at day + 30 (t1), + 60 (t2), + 120 (t3), + 180 (t4), and + 365 (t5). Differential methylation analysis was performed by using R software and CRAN/Bioconductor packages. Gene set enrichment analysis was carried out on promoter area of significantly differentially methylated genes by clusterProfiler package and the mSigDB genes sets. Results: Results show significant differences in the global methylation profile between HL and acute leukemias, and between patients with mixed and complete chimerism, with a strong methylation change, with prevailing hypermethylation, occurring 30 days after AHSCT. Functional analysis of promoter methylation changes identified genes involved in hematopoietic cell activation, differentiation, shaping, and movement. This could be a consequence of donor cell “adaptation” in recipient BM niche. Interestingly, this epigenetic remodeling was reversible, since methylation returns similar to that of donor HSPCs after 1 year. Only for a pool of genes, mainly involved in dynamic shaping and trafficking, the DNA methylation changes acquired after 30 days were maintained for up to 1 year post-transplant. Finally, preliminary data suggest that the methylation profile could be used as predictor of relapse in ALL. Conclusions: Overall, these data provide insights into the DNA methylation changes of HSPCs after transplantation and a new framework to investigate epigenetics of AHSCT and its outcomes
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