Σ−\Sigma^- Photoproduction on the Neutron: Results from CLAS

As part of a broader study of kaon photoproduction on deuterium, the $\gamma n \to K^{+} \Sigma^{-}$ channel was investigated. The data were acquired at Jefferson Lab using the CLAS detector and the Photon-Tagging Facility installed in Hall B. The photon energy range covered was from 0.50 to 2.95 GeV. For the present analysis, the $\gamma n \to K^{+} \Sigma^{-}$ channel was identified by detecting the positive kaon in coincidence with both decay products of the $\Sigma^-$ hyperon, $\pi^-$ and $n$. Preliminary differential cross--sections are shown as a function of the invariant energy W and the kaon polar angle in the center of mass system.Comment: 9 pages, 5 figures, INPC2001 proceeding

Direct observation of quark-hadron duality in the free neutron F-2 structure function

Using the recently published data from the BONuS(Barely Off-shell Nucleon Structure) experiment at Jefferson Lab, which utilized a spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F-2 structure function. The data are used to reconstruct the lowest few (N = 2, 4, and 6) moments of F-2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark-hadron duality holds locally for the neutron in the second and third resonance regions down to Q(2) approximate to 1 GeV2, with violations possibly up to 20% observed in the first resonance region

Direct Observation of Quark-Hadron Duality in the Free Neutron F\u3csub\u3e2\u3c/sub\u3e Structure Function

Using the recently published data from the BONuS(Barely Off-shell Nucleon Structure) experiment at Jefferson Lab, which utilized a spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F2 structure function. The data are used to reconstruct the lowest few (N = 2, 4, and 6) moments of F2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark-hadron duality holds locally for the neutron in the second and third resonance regions down to Q2 approximate to 1 GeV2, with violations possibly up to 20% observed in the first resonance region

Износостойкость высокохромистых чугунов при ударном помоле абразива в присутствии коррозионно-активной среды

Представлены результаты испытаний чугунов, содержащих 2,24-2,59 % С, 2,07-3,13 % Mn и 9,7-28,4 % Cr, в условиях ударно-абразивного изнашивания в присутствии водных растворов щелочи и кислоты с варьированием рН от 14 до 1. Показано, что износ чугунов меняется в зависимости от рН раствора немонотонно, а характер влияния хрома на износ зависит от типа пульпы. Установлено, что чугуны с 20–28 % Cr в данных условиях изнашивания не имеют преимущества перед менее легированными хромом чугунами. В пульпе с резко кислой средой (рН=1) износ чугунов растет прямо пропорционально содержанию в них хрома.Представлено результати випробувань чавунів, що містять 2,24-2,59 % С, 2,07-3,13 % Mn і 9,7-28,4 % Cr, в умовах ударно-абразивного зношування в присутності водяних розчинів луги і кислоти з варіюванням рН від 14 до 1. Показано, що знос чавунів змінюється в залежності від рН розчину немонотонно, а характер впливу хрому на знос залежить від типу пульпи. Встановлено, що чавуни з 20-28 % Cr у даних умовах зношування не мають переваги перед менш легованими хромом чавунами. У пульпі з різко кислим середовищем (рН=1) знос чавунів зростає прямо пропорційно вмісту в них хрому.The results of the test cast iron, containing 2,24-2,59 % С, 2,07-3,13 % Mn and 9,7-28,4 % Cr, in condition is striking-abrasive wear in water solutions of alkali and acids with variation pH from 14 to 1 are presented. It is shown that wear of cast irons is changing depending on pH solution nonmonotonic, but nature of the influence of chromium on wear depends on type of the pulp. It is determined that cast irons with 20-28 % Cr in wear condition mentioned above has no advantage over cast irons with 10-12 % Cr. In pulp with sharply tart ambience (pH=1) wear of cast irons grows straight pro rata contents of chromium

Dwell-time computation for stability of switched systems with time delays

Cataloged from PDF version of article.The aim of this study is to find an improved dwell time that guarantees the stability of switched systems with heterogeneous constant time-delays. Piecewise Lyapunov-Krasovkii functionals are used for each candidate system to investigate the stability of the switched time-delayed system. Under the assumption that each candidate system is stable for small delay values, a sufficient condition for dwell-time that guarantees the asymptotic stability is derived. Numerical examples are given to compare the results with the previously obtained dwell-time bounds. © The Institution of Engineering and Technology 2013

STUDIES ON THE ATTACK PRODUCED BY THE CAMERARIA OHRIDELLA DESHKA-DIMIĆ SPECIES

The horse-chestnut leaf miner (Cameraria ohridella Deschka-Dimić) is a rather dangerous invasive pest because the larvae create galleries in the foliar apparatus of theAesculus hippocastanum L. horse-chestnut, and compromise the aesthetic aspect of the tree.During 2016 and 2017 in the southern area of Oltenia, there were made observations and determinations regarding the degree of damage and the monitoring of theCameraria ohridella Deschka-Dimić species under the microclimate conditions offered by Constantin Poroineanu Park in Caracal.Throughout the entire experimental period, a total number of 9649 adults were captured on the installed traps, out of which 4726 adults were captured in 2016 and more than 4923 adults were captured in 2017.The degree of infestation of the horse-chestnut leaves produced by theCameraria ohridella Deschka-Dimić species was obtained on the basis of the number of galleries/leaf/leaflet made by larvae in an average sample of 100 leaves. The number of galleries per leaf was of 20.9 in 2016 and 54.2 in 2017, the average of the years of research being of 37.5, and the number of galleries per leaflet fluctuated between 2.9 in 2016 and 7.7 in 2017, with an average of the years of research of 50.3

Locality of quark-hadron duality and deviations from quark counting rules above resonance region

We show how deviations from the dimensional scaling laws for exclusive processes may be related to a breakdown in the locality of quark-hadron duality. The essential principles are illustrated in a pedagogic model of a composite system with two spinless charged constituents, for which a dual picture for the low-energy resonance phenomena and high-energy scaling behavior can be established. We introduce the concept of "restricted locality" of quark-hadron duality and show how this results in deviations from the pQCD quark counting rules above the resonance region. In particular it can be a possible source for oscillations about the smooth quark counting rule, as seen e.g. in the 90-degree differential cross sections for $\gamma p\to \pi^+ n$.Comment: The way to present Eqs. (2), (4), (7) are changed while physics contents and calculations are left intact; Additional explanations for the forward and large-angle duality are added; Three more references are included; Version to appear on Phys. Rev. Let

Moments of the Proton F2 Structure Function at Low Q2

The Q^2 dependence of inclusive electron-proton scattering F_2 structure function data in both the nucleon resonance region and the deep inelastic region, at momentum transfers below 5 (GeV/c)^2, is investigated. Moments of F_2 are constructed, down to momentum transfers of Q^2 ~ 0.1 (GeV/c)^2. The second moment is only slowly varying with Q^2 down to Q^2 ~ 1 (GeV/c)^2, which is a reflection of duality. Below Q^2 of 1 (GeV/c)^2, the Q^2 dependence of the moments is predominantly governed by the elastic contribution, whereas the inelastic channels still seem governed by local duality.Comment: 11 page paper, 1 LaTeX file, 10 postscript figure file