Promoting microbial immobilization of soil nitrogen during restoration of abandoned agricultural fields by organic additions

Application of organic materials to soils to enhance N immobilization into microbial biomass, thereby reducing inorganic N concentrations, was studied as a management option to accelerate the reestablishment of the native vegetation on abandoned arable fields on sandy soils the Kiskunsag National Park, Hungary. Sucrose and sawdust were used at three different topographic sites over 4 years. N availability and extractable inorganic N concentrations were significantly reduced in all sites. Soil microbial biomass C and microbial biomass N increased significantly following C additions, but the microbial C to microbial N ratio remained unaffected. It is concluded that the combined application of the rapidly utilized C source (sucrose) promoted N immobilization, whereas the addition of the slowly utilized C source (sawdust) maintained the elevated microbial biomass C and microbial biomass N in the field.

Carbon addition alters vegetation composition on ex-arable fields

1. Recent changes in European agricultural policy have led to measures to reverse the loss of species-rich grasslands through the creation of new areas on ex-arable land. Ex-arable soils are often characterized by high inorganic nitrogen (N) levels, which lead to the rapid establishment of annual and fast-growing perennial species during the initial phase of habitat creation. The addition of carbon (C) to the soil has been suggested as a countermeasure to reduce plant-available N and alter competitive interactions among plant species. 2. To test the effect of C addition on habitat creation on ex-arable land, an experiment was set up on two recently abandoned fields in Switzerland and on two 6-year-old restoration sites in the UK. Carbon was added as a mixture of either sugar and sawdust or wood chips and sawdust during a period of 2 years. The effects of C addition on soil parameters and vegetation composition were assessed during the period of C additions and 1 year thereafter. 3. Soil nitrate concentrations were reduced at all sites within weeks of the first C addition, and remained low until cessation of the C additions. The overall effect of C addition on vegetation was a reduction in above-ground biomass and cover. At the Swiss sites, the addition of sugar and sawdust led to a relative increase in legume and forb cover and to a decrease in grass cover. The soil N availability, composition of soil micro-organisms and vegetation characteristics continued to be affected after cessation of C additions. 4. Synthesis and applications. The results suggest that C addition in grassland restoration is a useful management method to reduce N availability on ex-arable land. Carbon addition alters the vegetation composition by creating gaps in the vegetation that facilitates the establishment of late-seral plant species, and is most effective when started immediately after the abandonment of arable fields and applied over several years.

First-order-reversal-curve analysis of Pr-Fe-B-based exchange spring magnets

Ribbons of nominal composition (Pr(9.5)Fe(84.5)B(6))(0.96)Cr(0.01)(TiC)(0.03) were produced by arc-melting and melt-spinning the alloys on a Cu wheel. X-ray diffraction (XRD) reveals two main phases, one based upon alpha-Fe and the other upon Pr(2)Fe(14)B. The ribbons show exchange spring behavior with H (c) = 12.5 kOe and (BH)(max) = 13.6 MGOe when these two phases are well coupled. Transmission electron microscopy revealed the coupled behavior is observed when the microstructure consists predominantly of alpha-Fe grains (diameter similar to 100 nm.) surrounded by hard material containing Pr(2)Fe(14)B. The microstructure is discussed in terms of a calculation by Skomski and Coey. A first-order-reversal-curve (FORC) analysis was performed for both a well-coupled sample and a poorly coupled sample. The FORC diagrams show two strong peaks for both the poorly coupled sample and for the well-coupled material. In both cases, the localization of the FORC probability suggests magnetizing interactions between particles. Switching field distributions were calculated and are consistent with the sample microstructure.

First-order-reversal-curve analysis of Pr-Fe-B-based nanocomposites

Ribbons of nominal composition (Pr(9.5)Fe(84.5)B(6))(0.96)Cr(0.01)(TiC)(0.03) were produced by arc-melting and melt-spinning the alloys on a Cu wheel. X-ray diffraction reveals two main phases, one based upon alpha-Fe and the other upon Pr(2)Fe(14)B. The ribbons show exchange spring behavior with H(c)=12.5 kOe and (BH)(max)= 13.6 MGOe when these two phases are well coupled. Transmission electron microscopy revealed that the coupled behavior is observed when the microstructure consists predominantly of alpha-Fe grains(diameter similar to 100 nm.) surrounded by hard material containing Pr(2)Fe(14)B. A first-order-reversal-curve (FORC) analysis was performed for both a well-coupled sample and a partially-coupled sample. The FORC diagrams show two strong peaks for both the partially-coupled sample and for the well coupled material. In both cases, the localization of the FORC probability suggests demagnetizing interactions between particles. Switching field distributions were calculated and are consistent with the sample microstructure. (C) 2009 Elsevier B.V. All rights reserved.

Effect of Ti-C and Cr Additions on Magnetic Properties of Nanocrystalline (Pr,Nd)-Fe-B Alloys

The addition of both Ti-C and Cr as grain refiners in Nd-Fe-B nanocomposites substantially increases the coercive field Hc. This motived our investigation of the effect of Ti-C and Cr on Pr-Fe-B nanocomposites. Melt-spun ribbons of composition (Pr(9.5)Fe(84.5)B(6))(0.97-x)Cr(x)(TiC)(0.03)(x = 0; 0.25; 0.5; 0.75; 1) and (Nd(9.5)Fe(84.5)B(6))(0.97-x)Cr(x)(TiC)(0.03)(x = 0.5 and 1) were produced for study. For a Pr nanocomposite with 1% Cr, Hc = 12.5 kOe. However, the energy product was limited to 13.6 MGOe by the remanence value. Rietveld analysis of X-ray spectra showed the ribbons to consist of predominantly hard (similar to 70 wt%) R(2)Fe(14)B, the soft phase being (similar to 30 wt%) alpha-Fe. Mossbauer measurements at 300 K are consistent with a reduced hyperfine field for the hard magnetic phase due to the Cr addition. Analysis of transmission electron microscopy images showed the Pr nanocomposite with 1% Cr to have an increased average grain size.

The effect of Nb, Mo, and A1 additions on the transformation behaviour and mechanical properties of thermomechanically processed C-Si-Mn trip steel

The effect of additions of Nb, A1 and Mo to Fe-C-Mn-Si TRIP steels on the final microstructure and mechanical properties after simulated thermomechanical processing (TMP) has been studied. Laboratory simulations of continuous cooling during TMP were performed using a quench deformation dilatometer, while laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. From this a comprehensive understanding of the structural and kinetic aspects of the bainite transformation in these types of TRIP steels has been developed. All samples were characterised using optical microscopy and XRD. The relationships between the morphology of bainitic structure, volume fraction, stability of RA and mechanical properties were investigated.

The influence of B4C and MgB2 additions on the behavior of MgO-C bricks

Carbon-containing refractory materials have received great attention over the last years due to their importance in the steelmaking process. The oxidation of carbon present in refractory materials at temperatures above 500 degrees C is usually accompanied by the decrease of their mechanical strength and chemical resistance. Aiming to improve the oxidation resistance of carbon-oxide refractories, the use of materials known as antioxidants has been extensively studied. In this work we evaluated the performance of MgB2 and B4C antioxidants when incorporated into MgO-C bricks. We observed that the co-addition of metallic antioxidants and B4C or MgB2 leads to refractory bricks with enhanced hot modulus of rupture and resistance against oxidation and slag corrosion. However, the excessive addition of these antioxidants could impair the performance of the obtained bricks. Thus, when determining the optimum concentration of MgB2 and B4C to be added into MgO-C refractories, one must take into consideration this behavior. (c) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Boyer's French dictionary: comprising all the additions and improvements of the latest Paris and London editions, with a very large number of useful words and phrases, now first selected from the modern dictionaries of Boiste, Wailly, Catineau, and others; with the pronunciation of each word, according to the dictionary of the Abbé Tardy: to which are prefixed, rules for the pronunciation of French vowels, diphthongs, and final consonants, chiefly collected from the prosody of the Abbé d'Olivet, with a table of French verbs, &c.

Acompañado de: An English-French dictionary, designed as a second part to the Boston edition of Boyer's French dictionary, with Tardy's pronunciation.

The Wye tour, or Gilpin on the Wye, with picturesque additions, from Wheatley, Price, &c. and archaeological illustrations.

Mode of access: Internet.

Adam's Latin grammar : with numerous additions and improvements, designed to aid the more advanced student by fuller elucidations of the Latin classics / by C.D. Cleveland.

Mode of access: Internet.

Elements of rhetoric : comprising the substance of the article in the Encyclopaedia Metropolitana, with additions, &c. /

Includes index.

Elements of rhetoric : comprising the substance of the article in the Encyclopædia Metropolitana with additions, &c. /

Includes index.

Elements of rhetoric. Comprising the substance of the article in the Encyclopædia Metropolitana with additions, &c.

Mode of access: Internet.