GEM-based beam profile monitors for the antiproton decelerator

The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light, ~0.4% X0, as required by the low energy of the antiprotons, 5.3 MeV. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPC) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another five detectors now installed in the ASACUSA and AEGIS beam lines. We will provide a detailed description of the detector and discuss the results obtained. The success of these detectors in the AD makes GEM-based detectors likely candidates for upgrade of the beam profile monitors in all experimental areas at CERN. The various types of MWPC currently in use are aging and becoming increasingly difficult to maintain.Comment: Presented at the second Micropattern Gaseous Detector conference 2011 (MPGD2011), Agust 2011, Kobe, Japa

Risk assessment methodology in wastewater safety plans. A case study

Na prossecução dos objetivos do milénio da ONU, o aumento e melhoraria do acesso a sistemas de saneamento básico seguros e sustentáveis continuam a ser uma prioridade de intervenção crítica e essencial para salvaguarda da saúde humana e qualidade de vida das populações. O desenvolvimento, implementação e monitorização de Planos de Segurança, aplicados às diferentes fases do ciclo urbano da água, são uma estratégia crucial, recomendada pela OMS, para prevenção, análise e mitigação do risco associado a perigos e eventos perigosos com impacto nocivo na saúde pública e no meio ambiente. O objectivo deste trabalho é dar um contributo metodológico para a análise do risco em Planos de Segurança de Águas Residuais (PSAR), por meio quer da formulação de um novo método semiquantitativo de avaliação do risco em PSAR e sua aplicação a um caso de estudo, quer de uma abordagem integrada do sistema de saneamento, incluindo as suas interações com a respectiva bacia hidrográfica. Concluiu-se que o nível e tipologia do risco dependem da abrangência geográfica da bacia hidrográfica considerada, a qual influencia não só a diversidade dos perigos e eventos perigosos identificados, mas também a definição das medidas de controle do risco a implementar, resultantes da necessária abordagem de barreiras múltiplas, no sentido de eliminar ou minimizar os riscos para os diversos utilizadores e operadores de um sistema urbano de águas residuais.In pursuit of the UN's millennium goals, increasing and improving access to safe and sustainable sanitation systems remains a critical intervention priority to safeguard human health, life quality and population wellness. The development, implementation and monitoring of Safety Plans, applied to the different sections of the urban water cycle, is a crucial strategy, recommended by WHO, for the prevention, analysis and risk mitigation due to hazards and dangerous events with a harmful impact on public health and the environment. This work intends to make a methodological contribution for risk analysis in Wastewater Safety Plans (WWSP), through a comprehensive approach to the full sanitation system, including its catchment watershed interaction, and the proposal of a new semi-quantitative risk assessment method applied to a case study. It was concluded that the risk level and typology depends on the geographical scope of the considered watershed, which significantly influences not only the diversity of identified hazards and dangerous events, but also the definition of risk control measures to be implemented, arising from a multiple barriers approach, in order to provide a risk mitigation for the several wastewater system users and operator

Concept for a Time-of-Flight Small Angle Neutron Scattering Instrument at the European Spallation Source

A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards um and tens of um, respectively. Two 1m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.Comment: 18 pages, 10 figure

Vulnerability assessment of real water distribution networks using the TV-WPN informatics tool

The design, operation and rehabilitation of water supply systems must have an asset management strategy, addressing hydraulic, technical, economic, social, environmental, and health issues with a high level of complexity. The vulnerability assessment and the resilience increment of a water distribution networks can be supported by the emerging Theory of Vulnerability of Water Pipe Networks (TV-WPN), which allows to systematize failure scenarios and map the major disproportions between failure consequences and the initial damage. Failure scenarios are defined leading simultaneously with hydraulic capacity deterioration and structural integrity, the main issues of water networks safety. The manual application of TV-WPN is almost impossible to be used in real-world water networks. So, it was initially tested using only simple theoretical networks, needing a new and more expeditious tool (like an automatic computation program) that could encourage its use by designers and managers of this type of hydraulic infrastructure. The recent development of the TV-WPN software tool allowed to speed up the calculation process, enabling the application of this theory to real water supply networks. This work presents the application of tool to a real water distribution network located in a village of Braga municipality for analyze their hydraulic performance and vulnerability, as well as to check and evaluate TV-WPN performance in a real-world case. It was concluded that the frequent presence of pipelines with very low flow velocities (due to the imposition of regulatory minimum diameters) can compromise the successful application of this software to real water distribution networks, namely in rural areas where flow rates are generally lower. However it is also an opportunity for future developments

On exact time-averages of a massive Poisson particle

In this work we study, under the Stratonovich definition, the problem of the damped oscillatory massive particle subject to a heterogeneous Poisson noise characterised by a rate of events, \lambda (t), and a magnitude, \Phi, following an exponential distribution. We tackle the problem by performing exact time-averages over the noise in a similar way to previous works analysing the problem of the Brownian particle. From this procedure we obtain the long-term equilibrium distributions of position and velocity as well as analytical asymptotic expressions for the injection and dissipation of energy terms. Considerations on the emergence of stochastic resonance in this type of system are also set forth.Comment: 21 pages, 5 figures. To be published in Journal of Statistical Mechanics: Theory and Experimen

Neuroevolutionary multiobjective optimization of injection stretch blow molding process in the blowing phase

Injection stretch blow molding is a very important thermoplastic processing technique producing hollow containers with mechanical performance. One of the main challenges in optimizing this process consists in finding the best thickness profile for each part in order to achieve the desired mechanical properties with less material use. In a previous study, a new methodology based on a neuroevolutionary multiobjective optimization approach was proposed to enhance the entire process, which considers that the process is optimized by phases, starting by the end. In that initial study only the final phase of the process was addressed, where the best thickness profile for an industrial bottle was found in order to satisfy the required mechanical properties with less material use. In the present study, the focus is the second stage of the optimization methodology, concerning the blowing phase of injection blow molding process. The optimal results obtained in the first phase are used as the optimal thickness profile for the bottle with the goal to find the best preform thickness profile which produces the desired bottle. The same procedures are used and the results show that the methodology was successfully applied to its second phase.This work has been supported by the European project MSCA-RISE-2015, NEWEX, with reference 734205

Contribution for the vulnerability assessment of water pipe network systems

Water pipe network systems are key public utilities which require being robust, protected and preserved. Knowing their weaknesses will help these processes. The theory of vulnerability of water pipe networks can contribute in this context because it is able to map the vulnerable parts of this type of system. The meaning of vulnerability has been defined as being the disproportionateness of the failure consequences in relation to the initial damage and, in particular, its theoretical concepts. The main objectives of this paper are to briefly introduce this theory, to illustrate its application highlighting its potential. The application of the theory is presented using an example of a simple water pipe network. In a real water supply utility, where the vulnerabilities of WPN components are less evident, the identification of the most vulnerable ones may play an important contribution as support decision during WPN design period and for a sustainable infrastructure asset management. Further work is in progress to account for different type of damage and consequences and thus manage risks due to failure scenarios not identified by the classical theories

Insulation lifetime improvement of polyimide thin film neural implants

Objective. This work deals with studying and improving the insulation lifetime of polyimideinsulated thin film neural implants, or related polyimide-based medical implants. Approach. The evolution of the leak impedance of insulated conductors was investigated in saline water at 40 °C. The fabrication process as commonly found in literature for polyimide/platinum/ polyimide microelectrode arrays was compared with three possible improvements: one based on lowering the curing temperature of the lower layer, one based on chemical activation and one based on an additional plasma activation step. Main results. The lower curing temperature process was found to yield a 7.5-fold improved lifetime compared with the state of the art process. Also, the leak impedances found after soak testing are an order of magnitude higher compared to the standard process. Significance. By improving the lifetime and insulation impedance of polyimide insulation with one order of magnitude, this work increases the applicability of polyimide in chronic thin film neural implants considerably.status: publishe