The two-echelon capacitated vehicle routing problem: models and math-based heuristics

Multiechelon distribution systems are quite common in supply-chain and logistics. They are used by public administrations in their transportation and traffic planning strategies, as well as by companies, to model own distribution systems. In the literature, most of the studies address issues relating to the movement of flows throughout the system from their origins to their final destinations. Another recent trend is to focus on the management of the vehicle fleets required to provide transportation among different echelons. The aim of this paper is twofold. First, it introduces the family of two-echelon vehicle routing problems (VRPs), a term that broadly covers such settings, where the delivery from one or more depots to customers is managed by routing and consolidating freight through intermediate depots. Second, it considers in detail the basic version of two-echelon VRPs, the two-echelon capacitated VRP, which is an extension of the classical VRP in which the delivery is compulsorily delivered through intermediate depots, named satellites. A mathematical model for two-echelon capacitated VRP, some valid inequalities, and two math-heuristics based on the model are presented. Computational results of up to 50 customers and four satellites show the effectiveness of the methods developed

Resistência genética de clones de cajueiro anão precoce às principais fitomoléstias.

No processo seletivo de clones de cajueiro anão precoce, diversos atributos têm sido considerados. Entretanto, o uso da resistência genética a doenças ainda e pouco conhecida e explorada. Este trabalho se propos determinar a variabilidade genética e identificar genótipos resistentes de cajueiro anão precoce quanto a antracnose (Colletotrichum gloeosporioides), ao mofo preto (Pilgeriella anacardium) e a mancha-angular (Septoria anacardil), as doenças mais importantes da cultura no Brasil. Os coeficientes de determinação genotípica foram de 80,72%, 85,20% e 74,92% para a antracnose, mofo-preto e mancha-angular, respectivamente. Os clones que demonstraram maior grau de resistência foram CAP 14, CAP 17, CAP 05 e CAP 07, para a antracnose; CAP 08, CAP 17 e CAP 11, para o mofo-preto e CAP 02, CAP 05 e CAP 03, para a mancha-angular. Verificou-se que entre os clones comerciais, o CCP 06 apresentou maior resistência a antracnose e ao mofo-preto, enquanto que os clones CCP 76 e CCP 1001 foram mais suscetíveis ao mofo-preto e o CCP 09 a antracnose. Os resultados indicam ampla variabilidade genética entre os clones, para todas as doenças avaliadas, possibilitando progresso genético por meio de seleção fenotípica.bitstream/CNPAT-2010/5486/1/Bp-034.pd

Closed trajectories of a particle model on null curves in anti-de Sitter 3-space

We study the existence of closed trajectories of a particle model on null curves in anti-de Sitter 3-space defined by a functional which is linear in the curvature of the particle path. Explicit expressions for the trajectories are found and the existence of infinitely many closed trajectories is proved.Comment: 12 pages, 1 figur

Concentração da solução de injeção e frequência de fertirrigação em latossolo amarelo.

A concentração da solução de injeção tem sido pouco considerada na fertirrigação. Entretanto ela pode influenciar o estado salino do solo, com risco de aumentos instantâneos da salinidade, que pode com o tempo afetar as características químicas do solo, além de induzir problemas de entupimentos nos dutos de condução de água para as plantas. O trabalho objetivou definir o binômio concentração da solução de injeção e frequência de fertirrigação, isto é, definir a concentração da solução de injeção mais adequada para duas frequências de fertirrigação para a bananeira Grand Naine. O experimento foi realizado em solo de textura argilosa de Tabuleiro Costeiro com um delineamento experimental em blocos casualizados, em esquema fatorial 3 x 2 sendo três concentrações da solução de injeção (3, 10 e 15 g/L) x duas frequências de fertirrigação (3 e 7 dias). Foram avaliadas variáveis de crescimento e produção da bananeira e a condutividade elétrica do extrato de saturação (CEes) na zona radicular durante o ciclo da cultura. Os resultados mostraram que a faixa de concentração da solução injetora utilizada não acarretou elevação na CEes do solo suficiente para causar problemas de salinidade no mesmo ao longo do ciclo da bananeira. As diferentes concentrações e frequências de aplicação da solução injetora não tiveram efeito sobre a produtividade da cultivar estudada

Group Theory analysis of phonons in two-dimensional Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDCs) have emerged as a new two dimensional materials field since the monolayer and few-layer limits show different properties when compared to each other and to their respective bulk materials. For example, in some cases when the bulk material is exfoliated down to a monolayer, an indirect-to-direct band gap in the visible range is observed. The number of layers $N$ ($N$ even or odd) drives changes in space group symmetry that are reflected in the optical properties. The understanding of the space group symmetry as a function of the number of layers is therefore important for the correct interpretation of the experimental data. Here we present a thorough group theory study of the symmetry aspects relevant to optical and spectroscopic analysis, for the most common polytypes of TMDCs, i.e. $2Ha$, $2Hc$ and $1T$, as a function of the number of layers. Real space symmetries, the group of the wave vectors, the relevance of inversion symmetry, irreducible representations of the vibrational modes, optical selection rules and Raman tensors are discussed.Comment: 32 pages, 4 figure

Analytical and numerical analysis of the behaviour of RC beams flexural strengthened with CFRP

Experimental research regarding the flexural strengthening of reinforced concrete (RC) structures with Carbon Fibre Reinforced (CFRP) systems using the Externally Bonded Reinforcing (EBR) and the Near Surface Mounted (NSM) techniques has been carried out at the University of Minho. Considering the experimental results of this research, the performance of the ACI and fib formulations for the EBR flexural strengthening was appraised in this paper. The same was done in terms of NSM technique adopting for the CFRP debonding strain a value that is 70% of the CFRP ultimate strain, according to the recommendations of the ACI Committee 440. However, the experimental results show that the CFRP debonding strain is dependent on the CFRP percentage and existing longitudinal steel reinforcement ratio. To estimate an equation for the prediction of the CFRP debonding strain, which takes into account these parameters, a numerical model was applied to the simulation of the tests carried out.(undefined

Evaluation of quality and yield of sugarcane (Saccharum officinarum) CB 47-355 variety to animal feeding in Porto Velho, Northern Brazil.

The aim of this study was to evaluate of quality and yield of sugarcane CB 47-355 variety, under conditions of Northern Brazil, in Porto Velho, RO. O objetivo deste estudo foi avaliar a qualidade e produtividade da cana CB 47-355 variedade, sob condições do Norte do Brasil, em Porto Velho, RO