Analysis of the velocity field of granular hopper flow

We report the analysis of radial characteristics of the flow of granular material through a conical hopper. The discharge is simulated for various orifice sizes and hopper opening angles. Velocity profiles are measured along two radial lines from the hopper cone vertex: along the main axis of the cone and along its wall. An approximate power law dependence on the distance from the orifice is observed for both profiles, although differences between them can be noted. In order to quantify these differences, we propose a Local Mass Flow index that is a promising tool in the direction of a more reliable classification of the flow regimes in hoppers

Production of exotic charmonium in γγ\gamma \gamma interactions at hadronic colliders

In this paper we investigate the Exotic Charmonium (EC) production in $\gamma \gamma$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC) energies as well as for the proposed energies of the Future Circular Collider (FCC). Our results demonstrate that the experimental study of these processes is feasible and can be used to constrain the theoretical decay widths and shed some light on the configuration of the considered multiquark states.Comment: 7 pages, 2 figures, 3 tables. v2: Revised version published in Physical Review

An 80 Mbit/s radiation-tolerant optical receiver for the CMS digital optical link

The CMS tracker slow control system will use approximately 1000 digital optical links for the transmission of timing, trigger and control signals. In this system, the 80 Mbit/s optical receiver at the detector end of each optical link has to be radiation hard since it will operate in the severe radiation environment of the CMS tracker (10 Mrad in 10 years). We have developed a prototype circuit in a 0.25 mu m commercial CMOS process using radiation tolerant layout practices to achieve the required radiation tolerance. This effective technique consists in the systematic use of enclosed (edgeless) NMOS transistors and guardrings, and relies in the natural total dose hardness of the thin gate oxide of deep submicron processes. The circuit features an automatic gain control loop allowing detection of wide dynamic range input signals (-20 to -3 d Bm) with minimum noise, compatible with the maximum expected radiation-induced drop in quantum efficiency of the PIN photodiode. A second feedback loop compensates a photodiode leakage current up to 100 mu A, and the circuit outputs an LVDS signal. Four receiver channels were integrated in a 2*2 mm/sup 2/ chip, out of which two were simultaneously bonded to two PIN photodiodes, and their BER performance was measured before and after an irradiation with 10 keV X-rays up to 20 Mrad (SiO/sub 2/). (11 refs)

Integrated pests management on mangoes at the São Francisco river Valley, Brazil.

Aiming at a rational pest control for this crop, sampling strategies for monitoring and action threshold for the main mango pests were determined based on field and laboratory observations, national and international literature reviews, and tests/adaptations of IPM strategies already in use in other countries

Ocorrência e caracterização dos danos de Erosomyia mangiferae na cultura da manga do Submédio do Vale do São Francisco.

A alteração no agroecossistema da mangueira, provocada pela expansão das áreas cultivadas na região do Submédio do Vale do São Francisco, tem propiciado condições favoráveis aos problemas fitossanitários, como o surgimento de novas pragas. Em meados de 1993, em um pomar comercial de mangueira, no município de Petrolina-PE, constatou-se a ocorrência de um pequeno díptero atacando os ponteiros e a panícula floral da mangueira identificado como Erosomyia mangiferae Felt (Diptera, Cecidomyiidae). Esta praga foi constatada atacando os tecidos tenros da planta, tais como: brotações e folhas novas, panícula floral e frutos do estádio de "chumbinho". Nas brotações e no eixo da inflorescêcia, observam-se pequenos orifícios, através dos quais há formação de galerias que se tornam necrosadas, apresentando, posteriormente, uma exsudação principalmente nas brotações. Nas folhas novas, ocorrem numerosas pontuações esbranquiçadas, contendo as larvas em seu interior. Estas pontuações, após a saída das larvas, tornam-se escuras e necrosadas, podendo ser facilmente confundidas com manchas fúngicas. Em consequência do ataque no eixo da inflorescência, a panícula floral apresenta uma curvatura de fácil visualização na planta, que caracteriza a presença dessa praga na cultura. Além do ataque no eixo da inflorescência, que pode ocasionar a perda total da panícula floral, E. mangiferae pode, também, danificar individualmente os botóes florais e os frutos recém-formados, provocando a queda dos mesmos.Coordenado por Abel Rebouças São José, Tiyoko Nair Hojo Rebouças, Daniel Nieto Angel, Ivan Vilas Bôas Souza, Nilma Oliveira Dias, Marinês Pereira Bomfim. Trabalhos apresentados no I Simpósio Latino Americano sobre Produção de Manga, 1999, Vitória da Conquista, BA