Jet energy density in hadron-hadron collisions at high energies

The average particle multiplicity density dN _ch/dη is the dynamical quantity that reflects some regularities of particle production in the low-p _T range. The quantity is an important ingredient of z scaling. Experimental results on charged particle density are available for pp, pA, and AA collisions, while experimental properties of the jet density are still an open question. The goal of this work is to find the variable that will reflect the main features of the jet production in a low transverse energy range and play the role of the scale factor for the scaling function ψ(z) and variable z in data z-presentation. The appropriate candidate is the variable we called “scaled jet energy density.” The scaled jet energy density is the probability of having a jet with defined E _T in defined x _T and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of the scaled jet energy density in proton-proton collisions over a high energy range and at η = 0. The properties of the new variable are discussed and sensitivity to “physical scenarios” applied in the standard Monte Carlo generator is noted. The results of the calculations of scaled jet energy density at LHC energies are presented and compared with predictions based on z scaling. The text was submitted by the authors in English.     

Computer simulation of the processes in a CR-39 neutron detector

The application of CR-39 as a fast neutron dosimeter, based on counting elastic recoil nuclei tracks of H, C and O nuclei in a geometrically matched pair of detectors, was studied. A computer simulation of the processes during the exposure of a detector pair to neutrons is presented. The energy and spatial distribution of the recoil nuclei was calculated with the MCNP 4B program package. On the basis of this distribution, a Monte-Carlo procedure for the generation of latent tracks in the CR-39 detectors was run. Additionally, a procedure for calculation of the chemical track etching for revealing the visible track parameters was performed to obtain the detector response.     

Time-of-flight measurements of heavy ions using Si PIN diodes

A new off-line timing method for PIN diode signals is presented which allows the plasma delay effect to be suppressed. Velocities of heavy ions measured by the new method are in good agreement within a wide range of masses and energies with velocities measured by time stamp detectors based on microchannel plates.     

A note on hybridization process applied on transformed double step size model

Numerical Algorithms - We introduce a hybrid gradient model for solving unconstrained optimization problems based on one specific accelerated gradient iteration. Having applied a three term...     

Novel Sorbent and Solvent Combination for QuEChERS Soil Sample Preparation for the Determination of Polycyclic Aromatic Hydrocarbons by Gas Chromatography–Mass Spectrometry

Polycyclic aromatic hydrocarbons (PAHs) represent priority contaminants, and the development of fast, reliable and accurate methods for their determination is of essential importance. The soil is a part of the environment which easily accumulates PAHs, making them available for transport to the air and water over long time periods and by plants through the food chain to humans. The aim of present study was to introduce a novel sorbent to the quick, easy, cheap, effective, rugged, and safe technique for soil sample preparation for the determination of 16 European Union priority PAHs by gas chromatography–mass spectrometry. Two solvent systems, 2:1 (v/v) hexane:acetone and ethyl acetate, were investigated in combination with five clean-up sorbents [Primary secondary amine (PSA), C18, florisil, clinoptilolite, and diatomaceous earth] in this study. The highest overall recovery of the method was achieved by the combination of hexane:acetone with clinoptilolite (recoveries of 70–110%) with limits of detection in the range of 0.60–1.53?µg?kg^?1. The analysis of 20 soil samples from Ni?, Serbia resulted in the identification of 11 samples with concentration greater than the values prescribed by law. The ratios of phenanthrene/anthracene and fluoranthene/pyrene were used to elucidate the origin of the PAHs as pyrolytic.     

Reactions of ortho-substituted α,α-dibromoacetophenones with nucleophiles: first examples of combined carbophilic and bromophilic attack on C-Br bonds

An efficient method for the formation of α-carbonyl-monosubstituted acetophenones from ortho-methoxy- and ortho-hydroxy-α,α-dibromoacetophenones and a range of selected nucleophiles, occurring via a carbophilic substitution/bromophilic substitution/protonation cascade process, is described. In turn, the preparation of α,α-dibromoacetophenones, isolated in high yields, relies on the neighboring group participation of the ortho-substituents in the starting ortho-substituted acetophenones.     

Total charge-changing and partial cross-section measurements in the reaction of 110 MeV/u C with paraffin

We have measured the total and partial charge-changing cross-sections (Z=5) after the passage of a 110 MeV/u ¹²C beam through an assembly consisting of CR-39 thin detectors and paraffin targets. These experimental cross-sections were compared to the predictions of known models. It was found that the measured total cross-sections agree with the model calculations to within about 8% or even less, while, depending on a model, discrepancies of up to a factor 1.2 higher and up to a factor 2.7 lower values of cross-sections for the production of fragment with Z=5 were observed.     

The influence of the nanofiller on thermal properties of thermoplastic polyurethane elastomers

Pure Fe₃O₄ and Mn-doped Fe₃O₄ nanoparticles were synthesized by simple wet chemical reduction technique using nontoxic precursors. Manganese doping of two concentrations, 10 and 15%, were employed. All the three synthesized nanoparticles were characterized by stoichiometry, crystal structure, and surface morphology. Thermal studies on as-synthesized nanoparticles of pure ferrite (Fe₃O₄) and manganese (Mn) doped ferrites were carried out. The thermal analysis of the three as-synthesized nanoparticles was done by thermogravimetric (TG), differential thermogravimetric, and differential thermal analysis techniques. All the thermal analyses were done in nitrogen atmosphere in the temperature range of 308–1233 K. All the thermocurves were recorded for three heating rates of 10, 15, and 20 K min^?1. The TG curves showed three steps thermal decomposition for Fe₃O₄ and two steps thermal decompositions for Mn-doped Fe₃O₄ nanoparticles. The kinetic parameters of the three as-synthesized nanoparticles were evaluated from the thermocurves employing Kissinger–Akahira–Sunose (KAS) method. The thermocurves and evaluated kinetic parameters are discussed in this paper.     

Volatiles composition and antioxidant activity Inula oculus-christi L. from Serbia

Abstract

The chemical composition of the essential oil and the volatiles obtained by static headspace (HS) of Inula oculus-christi L. is presented. The GC-MS analysis of the hydrodistilled oil resulted in the identification of 90 components, representing 92.7% of the oil. The most abundant compounds were: caryophyllene oxide (9.8%), trans-longipinocarveol (9.2%), eucalyptol (7.3%) and intermedeol (6.2%). The major constituent of I. oculus-christi L. HS volatiles was eucalyptol (87.4%). The antioxidant activity was evaluated by four different methods: 2,2-diphenyl-1-picryl-hydrazylhydrate free radical assay (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method, total reducing power (TRP), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC). Total phenolic content in (TPC) examined oil was 177.95?µg GAE/mg oil. Radical scavenging potential of the oil was promising RSC-DPPH was 57.4% and RSC-ABTS was 82.7%.