Reed canary grass yield and fuel quality in Estonian farmers’ fields

Reed canary grass (Phalaris arundinacea) is one of the possible raw materials for bioenergy production in northern Europe. Its cultivation is favoured because its high productivity and local origin. However, problems with the biomass quality for combustion have been reported. Usually delayed harvest in spring is suggested to improve the quality and decrease the moisture content of biomass. On the other hand, the feasibility of spring harvest depends on local climatic conditions and may cause yield losses. In current paper we studied reed canary grass fields in Estonia locating on different soil types and cultivated with various varieties. The influence of several fertilisation schemes on biomass yield was analysed. Our results indicated that production was higher on mineral soils than on the organic soil of abandoned peat extraction sites. Even different types of fertilisation did not increase the production on organic soils to the level comparable to those on mineral soils. Among studied varieties ‘Venture’ had the highest production. The highest yield per area was obtained late in the autumn (12.7 t d.w. per ha and 7.2 t d.w. per ha on mineral and organic soils, respectively). By spring the amount of biomass had decreased in all studied sites. Due to wet soil some of the fields remained unharvested, the others had high yield losses during practical harvesting. The chemical analyses did not reveal significant differences in the composition of biomass between late autumn and spring. Therefore we conclude that late autumn harvest should be preferred in local climatic conditions.     

A Novel Oxidation of Valine by N-Bromophthalimide in the Presence of Ruthenium(III) Chloride as a Homogeneous Catalyst

Kinetics of Ruthenium(III) [Ru(III)] chloride catalyzed oxidation of valine (Val) has been studied by N-bromophthalimide (NBP) in the acidic medium at 35 °C. The reaction rate follows first-order and zero-order dependence with respect to [NBP] and [Val]. First-order kinetics was observed for Ru(III) chloride at low range of concentrations and tending towards zero-order at higher concentrations. A negative effect was observed for [H⁺] and [phthalimide], while a positive effect was observed for [Cl^?] on the reaction rate. Hg(OAc)₂, ionic strength (I), and dielectric constant (D) of the medium did not change significantly the reaction rate. The rate constants as a function of temperature (298–318 K) were used to calculate activation parameters of the oxidation of Val by NBP. A plausible mechanism was proposed to explain the results of kinetic studies, reaction stoichiometry and product analysis.     

Kinetics and Mechanism of Ru(III)-Catalyzed Oxidation of Paracetamol by Chloramine-T in Aqueous Acidic Medium

The present paper deals with the kinetics and mechanism of Ru(III)-catalyzed oxidation of paracetamol by chloramine-T (CAT) in aqueous perchloric acid medium at 303 K. The experimental result shows a first order dependence on paracetamol at its low concentrations, but tending towards zeroth order at its higher concentrations. The reactions follow a first order rate dependence with respect to oxidant [CAT] and [Ru(III)]. The reaction showed negative fractional-order dependence on the rate for [H⁺] and p-toluenesulphonamide. Variation in [Cl^?] and ionic strength of the medium did not bring about any significant change on the rate of reaction. The decrease in the reaction rate with decrease in the dielectric constant of the medium was observed in the oxidation of paracetamol. Kinetic and equivalence studies together with product analysis, observed effect of dielectric constant of the medium on the rate of reaction and activation parameters furnished a basis for the formation of a common reaction mechanism for the Ru(III)-catalyzed oxidation of paracetamol by CAT in the acidic medium.     

Nonaqueous phase synthesis of copper nanoparticles

Copper nanoparticles were synthesized in a nonaqueous solution of cetyltrimethylammonium bromide with isopropanol as a solvent. Cetyltrimethylammonium bromide in isopropanol is observed to play a role as a catalyst where isopropanol is the reducing agent. The surface plasmon band characteristic for Cu nanoparticles can be observed at approximately 560 nm in the UV-visible spectra at molar ratios for Cu2+: cetyltrimethylammonium bromide of 1:15 and 1:30. On the other hand, at molar ratios of 1:0.25 and 1:1 the presence of peak at approximately 310 nm can be attributed to oligomeric clusters of Cu0. Formation of Cu0 was further confirmed from the X-ray diffraction analysis. The diffractograms exhibited peaks at 2theta = approximately 41.6 degrees, approximately 51.6 degrees, and approximately 74.3 degrees, corresponding to Cu0. At lower concentration of cetyltrimethylammonium bromide (i.e., Cu2+: cetyltrimethylammonium bromide = 1:0.25) higher degree of size dispersity (particles between approximately 5-20 nm) can be noted from transmission electron micrograph. On the other hand, at the highest concentration of cetyltrimethylammonium bromide (i.e., Cu2+: cetyltrimethylammonium bromide = 1:30), formation of finer sized particles with a lower degree of size variation, approximately 2-10 nm, can be observed.     

Kinetics of glycine oxidation by N-bromophthalimide in the presence of sodium dodecyl sulfate

The kinetics of oxidation of glycine by N-bromophthalimide (NBP) were studied in the presence of an anionic surfactant, sodium dodecyl sulfate, in acidic medium at 308 K. The rate of reaction was found to have first-order dependence on [NBP] and fractional-order dependence on [glycine] and [H⁺]. The addition of reduced product of the oxidant had no significant effect on the rate of reaction. Increasing [Hg(OAc)₂] and [Br⁻] increased the rate of reaction, whereas a change in ionic strength (μ) of the medium had no effect on oxidation velocity. The rate of reaction decreased with a decrease in dielectric constant of the medium. HCN was identified as the main oxidation product of the reactions. The various activation parameters have been computed. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.     

An Unsteady Subsurface Drainage Equation Incorporating Variability of Soil Drainage Properties

Almost all unsteady subsurface drainage equations developed so far use constant value of drainable porosity and hydraulic conductivity which may not be representative of entire drainage flow region. A drainage equation was, thus, developed incorporating depth-wise variability of drainable porosity (f) and hydraulic conductivity (K) of saline soils of Haryana state in India. The drain spacing with measured hydraulic heads at different periods of drainage were estimated by the developed equation and compared with the corresponding drain spacing estimated by commonly used unsteady drainage equations. The study revealed that the developed equation estimated the drain spacing that was nearest to the actual drain spacing of the existing subsurface drainage system, when a generally used design criterion of 30 cm water table drop in 2 days is considered. For a criterion of desired water table drop in 3 days and beyond, Glover equation was found to be the most superior. Hence, both the developed equation and Glover equation can be readily used with the associated design criteria for designing unsteady subsurface drainage systems in saline soils of the state of Haryana, India.     

Influence of Antisite Defects on the Thermoelectric Properties of Fe2VAl

Fe₂VAl is well known as a promising candidate for thermoelectric applications due to its sharp pseudogap at the Fermi level. However, its energy conversion performance is compromised by its high thermal conductivity. Our previous studies revealed that antisite defects like Al_V, Al_Fe, and V_Al are the most likely imperfections in Fe₂VAl [1]. It is thus important to understand the electron and phonon transport properties in these defective crystals to estimate their thermoelectric efficiency. Here we analyze the electronic transport properties of Fe₂VAl solid solutions based on Boltzmann transport theory within the constant relaxation time approximation. We then calculate the lattice thermal conductivity of Fe₂VAl containing Al_V antisite defects by solving the linearized Boltzmann transport equation based on an ab initio model for defects. We find a significant increase of around an order of magnitude in ZT at 300 K compared to the stoichiometric compound.     

Multivesicular liposome (DepoFoam) technology for the sustained delivery of insulin-like growth factor-I (IGF-I)

Insulin-like Growth Factor I (IGF-I), a 7.65 kD protein which has a variety of metabolic functions, is being evaluated for its therapeutic benefit in several disease states. To sustain therapeutic blood levels in a number of these instances, IGF-I needs to be administered repeatedly. The objective of these studies was the development of a sustained-release depot delivery system for this protein which would replace repeated administration. Using a multivesicular liposome drug delivery system (DepoFoam), sustained delivery kinetics have been observed for IGF-I. IGF-I was successfully encapsulated in this system with good efficiency. The integrity of the encapsulated protein was maintained, as characterized by physiochemical (HPLC, SDS-PAGE), and by biological methods (mitogenic activity). The DepoIGF-I particles were also characterized by their morphology (particles were smooth, multivesicular, and there was no debris), particle size (ranged from 18 to 20 microm), and in vitro and in vivo release kinetics of IGF-I. The DepoIGF-I particles released the protein drug in a sustained manner both in vitro and in vivo without a rapid initial release, and the released protein maintained its structural integrity and biological activity. The in vitro studies in human plasma at 37 degreesC showed that the DepoIGF-I particles released IGF-I slowly over several days; 70-80% of the protein was released in 6-7 days. In a pharmacokinetic in vivo study, after subcutaneous injections in rats, IGF-I levels were sustained for 5-7 days with DepoIGF-I formulation, whereas IGF-I in the free form was cleared in 1 day. DepoFoam technology provides a pharmaceutically useful system of sustained delivery for proteins, which can be extended to other therapeutic macromolecules.     

A Kinetic and Mechanistic Study on the Oxidation of Hydroxy Acids by <Emphasis Type="Italic">N</Emphasis>-Bromophthalimide in the Presence of a Micellar System

The kinetics of oxidation of some α-hydroxy acids viz. Tartaric acid (TA) and Malic acid (MA) by N-bromophthalimide (NBP) were studied in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), in perchloric acid medium at 313 K. The oxidation of TA and MA by N-bromophthalimide in the presence of CTAB is faster than in the absence of surfactant. The rate of oxidation of hydroxy acids was found to be in the order: TA > MA. First order kinetics with respect to NBP was observed in the oxidation of both hydroxy acids. The kinetics results indicate that the first order kinetics in hydroxy acids at lower concentrations tends towards a zero order at its higher concentrations. Inverse fractional order in [H⁺] and [phthalimide] were noted throughout its tenfold variation. With a progressive increase in [CTAB], the rate of reaction increased, reaches a maximum value and then constancy in k _Ψ was observed. Variation of [Hg(OAc)₂] and ionic strength (μ) of the medium did not bring about any significant change in the rate of reaction. The applicability of different kinetic models viz. the Piszkiewicz cooperative model, the Raghvan and Srinivasan model, and the Menger–Portnoy model were tested to explain the observed micellar effects. The effect of [CTAB] on the activation parameters was explored to rationalize the micellar effect. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.