Azimuthal anisotropy in S+Au reactions at 200 A GeV

Azimuthal correlations of photons produced at mid-rapidity in 200 A GeV S + Au collisions have been studied using a preshower photon multiplicity detector in the WA93 experiment. The Fourier expansion method has been employed to estimate the event plane via the anisotropy of the event as a function of centrality. The event plane correlation technique has been used to determine the true event anisotropy, beyond the anisotropy which arises due to finite multiplicity. The VENUS event generator with rescattering and proper simulation of the detector response can explain only a portion of the observed anisotropy. The residual anisotropy is found to be of the order of 5% for semi-central collisions. This suggests that directed collective flow of the produced particles is present at SPS energies. (C) 1997 Published by Elsevier Science B.V

Photochemical Generation and Reactivity of Naphthyl Cations: cine Substitution

The photochemical solvolyses of naphthalen-1-yl(phenyl)iodonium tetrafluoroborate and naphthalen-2-yl(phenyl)iodonium tetrafluoroborate in methanol regiospecifically yield the naphthalen-1- and -2-yl ethers but afford scrambled 1- and 2-phenylnaphthalene Friedel-Crafts products. It is demonstrated that singlet naphthyl cations account for the formation of the naphthyl ethers, but that the cine substitution is most likely to be due to the intermediacy of triplet naphthyl cations. According to the experiments reported here, the singlet naphthyl cations are lower in energy than their triplet isomers. High-level MO calculations for the cations in methanol support this finding

Photochemical Generation of Six- and Five-Membered Cyclic Vinyl Cations

[GRAPHICS] The photochemical solvolyses of 4-tert-butylcyclohex-1-enyl(phenyl)iodonium tetrafluoroborate (1) and cyclopent-1-enyl(phenyl)iodonium tetrafluoroborate (2) in methanol yield vinylic ethers and vinylic cycloalkenyliodoberizenes and cycloalkenylbenzene, which are the trapping products of the geometrically destabilized C-6-ring and C-5-ring vinyl cation with the solvent and with the leaving group iodobenzene. Iodonium salt 2 also yields an allylic ether and allylic cyclopentenyliodobenzenes and cyclopentenyl-benzene, which are the trapping products of the C-5-ring allylic cation produced from the C-5-ring vinyl cation by a hydride shift in a typical carbocationic rearrangement

Automated comparison of X-ray images for cargo scanning

Conference of 50th Annual IEEE International Carnahan Conference on Security Technology, ICCST 2016 ; Conference Date: 24 October 2016 Through 27 October 2016; Conference Code:125934International audienceCustoms administrations are responsible for the enforcement of fiscal integrity and security of movements of goods across land and sea borders. In order to verify whether the transported goods match the transport declaration, X-ray imaging of containers is used at many customs site worldwide. The main objective of the research and development project 'Automated Comparison of X-ray Images for Cargo Scanning (ACXIS)', which is funded by the European 7th Framework Program, is to improve the efficiency and effectiveness of the inspection procedures of cargo at customs using X-ray technology. The current inspection procedures are reviewed to identify risks, catalogue illegal cargo, and prioritize detection scenarios. Based on these results, we propose an integrated solution that provides automation, information exchange between customs administrations, and computer-based training modules for customs officers. Automated target recognition (ATR) functions analyze the X-ray image after a scan is made to detect certain types of goods such as cigarettes, weapons and drugs in the freight or container. Other helpful information can also be provided, such as the load homogeneity, total or partial weight, or the number of similar items. The ATR functions are provided as an option to the user. The X-ray image is transformed into a manufacturer-independent format through geometrical and spectral corrections and stored into a database along with the user feedback and other related data. This information can be exchanged with similar systems at other sites, thus facilitating information exchange between customs administrations. The database is seeded with over 30'000 examples of legitimate and illegal goods. These examples are used by the ATR functions through machine learning techniques, which are further strengthened by the information exchange. In order to improve X-ray image interpretation competency of human operators (customs officers), a computer-based training software is developed that simulates these new inspection procedures. A study is carried out to validate the effectiveness and efficiency of the computer-based training as well as the implemented procedures. Officers from the Dutch and Swiss Customs administrations partake in the study, covering both land and sea borders

Creating a reference database of cargo inspection X-ray images using high energy CT of cargo mock-ups

International audienceCustoms continue to use a wide range of technology in protecting against terrorism and the movement of illicit trade and prohibited imports. The throughput of scanned vehicles and cargo increases and just keeps on growing. Therefore, the need of automated algorithms to help screening officers in inspection, examination or surveillance of vehicles and containers is crucial. In this context, the successful collaboration between manufacturers and customs offices is of key importance. Facing this topic, within the seventh framework program of the European Commission, the project ACXIS “Automated Comparison of X-ray Images for cargo Scanning” arose. This project develops a reference database for X-ray images of illegal and legitimate cargo, procedures and algorithms to uniform X-ray images of different cargo scanners, and an automated identification of potentially illegal cargo

Non-intrusive inspection of cargo containers using the C-BORD Rapidly Relocatable Tagged Neutron Inspection System

The European H2020 project, entitled “effective Container inspection at BORDer control points” (C-BORD), aims to develop a framework of Non-Intrusive Inspection (NII) technologies, for containers and large-volume freight at the EU borders. In this article the first results of the field trials of the Rapidly Relocatable Tagged Neutron Inspection System (RRTNIS) are reported. The tests were carried out at the customs administration of the Netherlands' (DCA) facility in the seaport of Rotterdam, the Netherlands. For the tests mock-up cargo containers were prepared. The containers were analyzed using the whole set of NII subsystems of the C-BORD framework. Each container underwent a session of subsequent scans with all the subsystems, in order to realistically reproduce the normal flow of inspections at the customs facility. The RRTNIS was tested under these realistic conditions, as well. The system was able to separate and identify the target materials, in mock-up containers, and improve the state-of-the-art in terms of the detected quantities

Momentum distributions and interferometry analysis of negatively charged hadrons from 200 A GeV S+Au reactions

Two particle correlations and single particle P-T distributions have been measured for negatively charged hadrons from 200 A GeV S + Au reactions. The large acceptance of the WA93 dipole spectrometer enables the study of transverse momentum dependence of the multi-dimensional correlation function. A longitudinal radius decreasing with increasing transverse momentum is observed

Non-intrusive inspection of cargo containers using the C-BORD Rapidly Relocatable Tagged Neutron Inspection System

International audienceThe European H2020 project, entitled “effective Container inspection at BORDer control points” (C-BORD), aims to develop a framework of Non-Intrusive Inspection (NII) technologies, for containers and large-volume freight at the EU borders. In this article the first results of the field trials of the Rapidly Relocatable Tagged Neutron Inspection System (RRTNIS) are reported. The tests were carried out at the customs administration of the Netherlands' (DCA) facility in the seaport of Rotterdam, the Netherlands. For the tests mock-up cargo containers were prepared. The containers were analyzed using the whole set of NII subsystems of the C-BORD framework. Each container underwent a session of subsequent scans with all the subsystems, in order to realistically reproduce the normal flow of inspections at the customs facility. The RRTNIS was tested under these realistic conditions, as well. The system was able to separate and identify the target materials, in mock-up containers, and improve the state-of-the-art in terms of the detected quantities