Olive jift is a solid by-product of olive (Olea europea) oil processing. Greenhouse experiments were conducted to evaluate olive jift effect on broomrape (Orobanche spp.) infections on three crops. Soil—jift mixtures were used as potting medium in ratios of 1:0, 1:1, and 3:1 soil to jift. Broomrape seeds were evenly incorporated in the potting media at 0, 150, 300, 450, 600, 750, and 900 seeds/kg. Pots planted with faba bean or pea were inoculated with seeds of O. crenata Forsk., whereas pots planted with tomato were inoculated with seeds of O. lavandulacea Reichenb. Jift in soil reduced broomrape germination and infection on all three hosts regardless of inoculation densities. Pea was not infected with broomrape in jift-containing media at any inoculation density, whereas only sporadic broomrape infections were observed in faba bean and tomato grown in jift-mixed soils. Fresh and dry weights of all crops were not adversely affected by mixing jift with soil. These results suggest a possible use of jift as an inexpensive organic material for broomrape control.

The magnetized plasma-wall transition (MPWT) layer occurring, for example near a tokamak diverter, typically consists of three distinct sublayers: the Debye sheath (DS), the magnetic presheath (MPS) and the collisional presheath (CPS), with characteristic lengths λD (electron Debye length), ρi (ion gyroradius) and λ (smallest relevant ion collision length), respectively. For analytical simplicity one usually assumes the ordering λD ≪ ρi ≪ λ, or, equivalently, and (‘asymptotic three-scale (A3S) limit’), in which the three sublayers are precisely defined. In the present work the equations and length scales governing the transition, or the ‘intermediate’ regions between neighboring sublayers (DS–MPS, MPS–CPS), in the A3S limit are derived, allowing one to avoid the singularities arising from the ϵDm → 0 and ϵmc → 0 approximations. The MPS entrance and the related Bohm–Chodura condition is defined in a natural way. It is found that in the hydrodynamic Ti = 0 approximation the intermediate scales and equations have a universal form and a similar structure not only for the MPS–DS and CPS–MPS transitions but also for the DS–CPS transition in the non-magnetized case.

Recently, heteromolecular crystals of fullerene C60 and cubane (C8H8) have been synthesized. For some temperatures the C60 molecules are free to rotate whereas cubanes behave like a static bearing in a so-called rotor-stator phases. In this work we report classical and tight-binding molecular dynamics simulations in order to investigate the rotor-stator dynamics and polymerization processes. Our results show that, for 200 K and 400 K, cubane molecules remain basically fixed, presenting only thermal vibrations within the timescale of our simulations, while C60 fullerenes show rotational motions. Fullerenes perform “free” rotational motions at short times (< 1 ps), small amplitude hindered rotational motions (librations) at intermediate times, and rotational diffusive dynamics at long times (> 10 ps). Random copolymerization among cubanes and fullerenes were observed when temperature is increased, leading to the formation of a disordered structure.

Dense fully stabilized cubic zirconia, sintered by the spark plasma sintering (SPS) method, was characterized through hardness, fracture toughness, and electrical impedance measurements. The effect of sintering temperature on hardness and fracture toughness was evaluated. Samples sintered at 1200 °C for 5 min, which had crystallite size of <100 nm, exhibited the highest hardness. Impedance measurements showed an increase in bulk contribution relative to grain boundaries as sintering temperature is increased. Calculation of the activation energy for conduction gave a value, 1.13 eV, in agreement with previously published results.

The sintering of nanosize powders of fully stabilized zirconia was investigated using the spark plasma sintering (SPS) method. The influence of sintering temperature, heating rate, direct current pulse pattern, sintering time, and sintering pressure on the final density and grain size of the product was investigated. The dependence of densification on temperature showed a maximum at 1200 °C, resulting with nearly fully dense zirconia with a crystallite size of about 100 nm. Heating rate (50∼300 °C min−1) and sintering time (5–16 min) had no significant influence on the final density and the crystallite size. Pulsing patterns ranging from 2:2 to 48:2 (on:off) had no influence on the density or the crystallite size. However, the applied pressure had a significant influence on the final density but no apparent effect on crystallite size for a sintering temperature of 1200 °C and a hold time of 5 min.

The influence of mechanical activation on the characteristics and mechanism of ignition of self-propagating high-temperature synthesis processes of different silicides in the systems Me–Si (Me =Ti, Nb, Mo) was investigated. The results show that mechanical activation does not alter the mechanism involved but influences significantly the ignition characteristics. The influence, however, strongly depends on the stoichiometry of the mixtures. The composition Ti:Si = 1:2 shows the largest influence, with the ignition temperatures decreasing from 1400 °C for unmilled powders to about 600 °C for powders milled for several hours. The compositionsTi:Si = 5:3, Nb:Si = 1:2 show less pronounced decreases, while the compositionMo:Si = 1:2 shows no decrease. These differences are discussed in terms of the role of microstructure in the reaction mechanism and the different response of the systems to contamination, particularly from oxygen. The results suggest that for these systems self-ignition processes during milling cannot be explained only on the basis of the decrease in the ignition temperature.

The parameters of the mechanically activated field-activated pressure-assisted synthesis (MAFAPAS) process, which were recently developed and patented for producing dense nanostructured materials, were studied in the case of the B2-FeAl intermetallic. Based on x-ray diffraction (XRD) experiments, residual stresses XRD analysis, relative density measurement, and secondary-electron microscopic observations, the optimal synthesis conditions (time, current intensity, and pressure) were studied. Fe + Al powders were comilled in a specially designed planetary mill to obtain a mixture of reactants at the nanoscale without the formation of any product. The milled mixtures were then subjected to a high density of alternating current (60 Hz ac, total current 1250 or 1500 A), a uniaxial pressure (70 or 106 MPa), and different times (from 2 to 5 min). This work confirms the reproducibility of the MAFAPAS process, showing the essential role of the mechanical activation step to produce a pure nanostructured material. In addition, the composition and the microstructure of MAFAPAS end-products depended on the processing parameters (time, current density, mechanical pressure). In particular, it was observed that the process of simultaneous synthesis and consolidation of the product introduced a high level of residual stresses.

Microalloying of MoSi2 to form Mo(1−x)MexSi2 (Me = Nb or V) was investigated by the self-propagating high-temperature synthesis method. With alloying element contents up to 5 at.%, a homogeneous C11b solid solution was obtained. For higher contents of alloying elements, the product contained both the C11b and the hexagonal C40 phases. The relative amount of the C40 phase increases with an increase in the content of alloying metals in the starting mixture. The alloying element content in the hexagonal C40 Mo(1−x)MexSi2 phase was nearly constant at a level of about 12 at.% for all starting compositions. In contrast, the content of the alloying elements in the tetragonal phase is considerably lower (around 4 at.%) and increases slightly as the Me content in the starting mixture is increased.

The mechanochemical behavior of the Ti–Si system was investigated across the whole composition range at a constant milling intensity. At low Si content the mechanical alloying process leads progressively to an amorphous structure. In the central range of the equilibrium diagram, crystalline intermetallic compounds form with a combustion-like behavior. A nanostructured composite of TiSi2 gradually evolves above the Ti25Si75 stoichiometry. Transformation behaviors relate to the thermodynamic and thermochemical properties of the tested mixtures as well as with their mechanical features and structural refinement, which change drastically within the explored composition range.

The effect of the mechanical activation of the reactants on the self-propagating high-temperature synthesis (SHS) of titanium silicides was investigated. SHS experiments were performed on reactant powders that were milled for different times. Mechanical activation was shown to have a large influence on the combustion characteristics, particularly on wave speed. A much weaker effect was observed on the products phase composition. Single-phase products were obtained only from Ti:Si = 1:2 and Ti:Si = 5:3 starting compositions. Observation of microstructural evolution in quenched reactions of Ti:Si = 1:2 mixtures milled for relatively long times revealed that the combustion reaction was primarily a solid-state process restricted to a surface layer of the large Ti grains. A secondary process involving a solid–liquid interaction between solid Ti and melted Si was dominant in the post front region. The mechanical activation in this case took the role of increasing the contact surface between the reactants. A single reaction coalescence mechanism involving only liquid phases was proposed for the Ti:Si = 5:3 composition. For this composition the apparent activation energy for the overall combustion process was determined (155 kJ mol−1) and was shown to be independent on the degree of mechanical activation of the reactants.

The synthesis of silicides of tantalum (TaSi2, Ta5Si3, Ta2Si, and Ta3Si) by field-activated combustion synthesis was investigated. The phases TaSi2, Ta5Si3, and Ta2Si can be synthesized in relatively pure form through field activation. The first compound requires a threshold field of 6 V cm−1 to initiate a combustion wave. The second and third compounds can be synthesized with all field values (0 < E < 20 V cm−1), but require considerable ignition time when E = 0. The stoichiometry Ta3Si does not sustain a combusion front unless E ≥ 20 V cm−1. However, the product is not the desired single phase. Wave velocities in the synthesis of the Si-rich phase, TaSi2, are considerably lower than those of the other two and showed a much weaker dependence on the field. The mechanism of phase formation for TaSi2 and Ta5Si3 was investigated from frozen wave analysis. No intermediate phase forms in the TaSi2 case, while in the case of Ta5Si3, TaSi2 is present as an intermediate phase. Additional investigations on the mechanism of silicide formation included isothermal solid–solid diffusion-couple and solid–liquid experiments.

The use of an electric field to activate the combustion synthesis of chromium silicides was investigated. Despite their relatively low adiabatic temperatures, all four silicides were synthesized by field-activated combustion synthesis. However, although self-propagating synthesis reactions were initiated, the products were not pure but contained other silicides and reactant phases. The purity of the samples increased with increasing field strength, and under the highest field, the products contained the desired silicide as the major phase with minor amounts of other stoichiometries. Observation of microstructural evolution in quenched reactions revealed the key role played by the liquid phases in the propagation of the combustion front. The phase Cr5Si3 was the first product of the interaction between the reactants when either solid–solid or solid–liquid processes were involved. These results were confirmed by isothermal solid–solid and solid–liquid diffusion couple experiments.

A two-color array pyrometer was used to investigate morphological developments on the surface of materials undergoing self-propagating high-temperature reactions. Time sequences of temperature spatial profiles during wave propagation were found to be complex in their nature and dynamics. They contain features that are interpreted in terms of morphological changes during the process. These features include formation of cracks or voids, expansion of the sample, and formation of droplets of metals on the surface. The use of the array pyrometer for determination of the activation energy of the combustion reaction between Zr and NiO is reported.

This study is the first attempt to assess systematically the cognitive functioning in children diagnosed with typical cri du chat syndrome (CDCS) using neuropsychological test measures. Twenty-six children aged between 6 years 4 months and 15 years 5 months (mean 8 years 3 months) completed a battery of tasks measuring IQ level, receptive and expressive language skills, and articulation. Twenty-four children were in the severe learning-disability range with no specific verbal or performance profile. Using more finely tuned measures of cognition, however, a clear discrepancy in the pattern of language functioning was found with better receptive than expressive language skills. One implication of these findings is that parents and professionals should be more optimistic about the capacities of children with CDCS to understand more complex verbal commands than their expressive language skills would suggest.