The influence of the solvent on the epoxidation of cis,trans,trans-1,5,9-cyclododecatriene to trans-1,2-epoxy-cis,trans-5,9-cyclododecadiene by catalytic system tert-butyl hydroperoxide/Mo(CO)6

The epoxidation of cis,trans,trans-1,5,9-cyclododecatriene to trans-1,2-epoxy- cis,trans-5,9-cyclododecadiene with the use of commercial solution of tert-butyl hydroperoxide in various organic solvents:tert-butyl peroxide, isooctane, decane, and nonane was investigated. The process was investigated in different experimental conditions. The best results were achieved with the application of tert-butyl hydroperoxide in isooctane. A significant influence of the nature of the solvent on the results of trans-1,2-epoxy-cis,trans-5,9-cyclododecadiene synthesis was found.     

Effects of metabolizable protein supply and amino acid supplementation on nitrogen utilization, milk production, and ammonia emissions from manure in dairy cows

Two experiments were conducted with the objective of investigating the effects of rumen-protected methionine (RPMet) supplementation of metabolizable protein (MP)-deficient or MP-adequate but Met-deficient diets on dairy cow performance. Experiment (Exp.) 1 utilized 36 Holstein dairy cows blocked in 12 blocks of 3 cows each. Cows within block were assigned to one of the following dietary treatments: (1) MP-adequate diet [AMP; positive MP balance according to the National Research Council (2001) dairy model]; (2) an MP-deficient diet supplemented with 100g of rumen-protected Lys (RPLys)/cow per day (DMPL); and (3) DMPL supplemented with 24g of RPMet/cow per day (DMPLM). Experiment 2 utilized 120 Holstein cows assigned to 6 pens of 20 cows each. Pens (3 per treatment) were assigned to one of the following dietary treatments: (1) AMP diet supplemented with 76g of RPLys/cow per day (AMPL); and (2) AMPL (74g of RPLys/cow per day) supplemented with 24g of RPMet/cow per day (AMPLM). Each experiment lasted for 10wk (2-wk adaptation and 8-wk experimental periods) following a 2-wk covariate period (i.e., a total of 12wk). In Exp. 1, the MP-deficient diets decreased apparent total-tract nutrient digestibility but had no statistical effect on dry matter intake (DMI), milk yield, or milk fat percentage and yield. Compared with AMP, DMPL decreased milk protein content; both DMPL and DMPLM diets decreased milk protein yield. Urinary N losses and milk urea-N concentration were decreased by the MP-deficient diets compared with AMP. The ammonia emitting potential of manure from the MP-deficient diets was decreased by about 37% compared with that of AMP manure. Plasma Lys and Met concentrations were not affected by treatment, but concentrations of His, Thr, and Val were lower for the MP-deficient diets compared with AMP. In Exp. 2, the AMPLM diet had lower milk yield than AMPL due to numerically lower DMI; no other effects were observed in Exp. 2. In conclusion, feeding MP-deficient diets supplemented with RPLys and RPMet did not statistically decrease milk yield in dairy cows in Exp. 1. However, without RPMet supplementation, milk protein content was decreased compared with the MP-adequate diet. Other amino acids, possibly His, may limit milk production in MP-deficient, corn or corn silage-based diets. A summary of 97 individual cow data from trials in which MP-deficient diets were fed suggested the National Research Council (2001) model under-predicts milk yield in cows fed MP-deficient diets (MP balance of -20 to -666g/d) in a linear manner: milk yield under-prediction [National Research Council (2001) MP-allowable milk yield, kg/d - actual milk yield, kg/d] = 0.0991 (±0.0905) + 0.0230 (±0.0003) × MP balance, g/d (R(2)=0.99).     

Effect of protein level and methionine supplementation on dairy cows during the transition period

Cows experience a significant negative protein balance during the first 30 d of lactation. Given the functional effects of AA on health, especially in challenging periods such as calving, higher levels of protein and specific AA in the diet may act to improve health and feed intake. The response of dairy cows to 3 protein supplementation strategies during the transition period and through the first 45 d in milk was evaluated. The final data set had 39 Holstein cows blocked based on parity (primiparous vs. multiparous) and expected calving and randomly assigned within each block to one of 3 dietary treatments: low protein (LP), high protein (HP), or high protein plus rumen-protected methionine (HPM). Treatments were offered from d ?18 ± 5 to 45 d relative to parturition. Pre- and postpartum diets were formulated for high metabolizable protein (MP) supply from soybean meal, and HP and HPM provided higher MP balance than LP. Preplanned contrasts were LP versus HP+HPM and HP versus HPM. Significance was declared at P ≤ 0.05 and trends at 0.05 < P ≤ 0.10. Cows fed HP and HPM had greater fry matter intake (DMI) prepartum than LP (+2 kg/d), and there was a trend for greater DMI with HPM than with HP (+1.6 kg/d). Body weight and condition score before and after calving did not differ among treatments. High protein (HP and HPM) tended to increase milk yield during the first 45 d of lactation (+1.75 kg/d), increased milk lactose content and urea-N in milk and plasma, tended to increase blood BHB 14 d postpartum, and tended to reduce milk/DMI compared with LP. Blood concentrations of calcium at calving and of glucose, and nonesterified fatty acids pre- and postpartum did not differ. High protein induced lower concentration of plasma IL-1 at calving and lowered blood lymphocytes 21 d postpartum, suggestive of a reduced inflammatory status compared with LP. The concentrations of IL-10, tumor necrosis factor alpha, and other hemogram variables did not differ among treatments. Addition of rumen-protected methionine to the HP diet did not alter milk yield but increased fat and total solids concentrations. The rumen-protected methionine had no effect on blood metabolites and immunity markers, with the exception of increased pre-partum insulin concentrations. The data indicate that dairy cows around calving respond positively to an increase in the supply of MP and to rumen-protected methionine supplementation of the HP diet by increasing intake and improving immune status.     

Formation of cyanide as a product of decomposition of cyanogenic glucosides in the treatment of elderberry fruit (Sambucus nigra)

Distribution of cyanogenic glucosides contained in elderberry fruit was investigated in the course of technological operations usually utilised for obtaining musts. The degree of glucoside hydrolysis was estimated by the amount of liberated hydrogen cyanide. After fermentation on skins the must contained 2.08 mg litre^?1 of hydrogen cyanide. Hydrogen cyanide in the must from depectinised fruit pulp was at a level of 2.31 mg litre^?1. After heat treatment the must contained 1.07 mg litre^?1 of hydrogen cyanide.     

Modeling domains using Bézier surfaces in plane boundary problems defined by the Navier–Lame equation with body forces

The paper presents an effective and powerful way of solving boundary problems modeled by the Navier–Lame equation with body forces. We considered domains of complex shapes defined using Bézier surfaces, which are well-known in computer graphics. Obtained results were compared with analytical and numerical solutions received by the boundary element method (BEM). The analysis of the results has confirmed reliability and effectiveness of the proposed approach and its applicability to a variety of practical problems.     

Laser produced streams of Ge ions accelerated and optimized in the electric fields for implantation into SiO2 substrates

Ge crystals were prepared by means of laser-induced ion implantation technique. A Nd:YAG pulsed laser (repetition rate: 10 Hz; pulse duration: 3.5 ns; pulse energy: ～0.5 J) was used both as an ion source and to carry out the ablation processes. The optimization of the laser-generated ion beam parameters in a broad energy and current density range has been obtained controlling the electrostatic field parameters. Numerical simulations of the focusing system, performed adopting an OPERA 3D code, and an investigation of the ion characteristics, using the ion time-of-flight method, have allowed to optimize the preparation parameters. The structural properties of the samples were investigated by means of x-ray photoelectron, micro-Raman spectroscopies, and scanning electron microscopy techniques. Experimental results show that, by appropriately varying the ion implantation parameters and by a post-preparation annealing treatment, it is possible to achieve the development of a micrometer-sized crystalline Ge phase and∕or an amorphous one.     

The Stokes coagulation model

The coagulation problem related to the kinetic theory of motion of particles according to the Boltzmann equation. The coagulation equation brought from the infinite space to the limited one. A real boundary condition for the Stokes coagulation limiting the purified zones without the nonmetallic inclusions. The equivalent relative boundary conditions. The Stokes coagulation as function of time.     

Studies on the removal of phosphorus and sulfur from Fe-C and Fe-C-Mn melts at 1350°C

Laboratory studies have been performed on simultaneous dephosphorization and desulfurization of Si-free Fe-4.5 % C melts with [P]_o = 0.11 wt.% and [S]_o = 0.04 wt.% in MF induction furnaces at 1 350°C. In these investigations, CaO- or Na₂CO₃-based fluxes were used and the techniques of powder injection or single top slag addition were applied. The following results have been obtained:

• – The effectiveness of lime and soda-based fluxes with regard to dephosphorization is practically the same. But a lower sulfur level is attained when Na₂CO₃-based fluxes are used.
• – In the injection experiments, efficiencies of η_P = 80% for dephosphorization and η_s = 90% for desulfurization are easily reached at a powder consumption of 50 to 60 g/kg. But a further increase of the η values requires a remarkable increase in the amount of injected powder. Top slag addition instead of powder injection is less effective, in general.
• – Apparent rate constants k_[P] and k_[S] from 0.05 to 0.3 min^?1 have been determined in the initial stage of injection depending on the relative amount of injected flux. In the top slag experiments, the k_[P] and k_[S] values were practically constant at a level of 0.1 min^?1.

Furthermore, dephosphorization of molten Fe-C-Mn alloys at 1 350°C has been studied at variable Mn content. It is predicted from thermodynamic data and confirmed by experiments that dephosphorization lessens with increasing Mn content in the range from 0 to 15 wt.%.