Estudo transiente de um pressurizador de um reator a água pressurizada (PWR)

O objetivo da presente estudo e prover um método apropriada para o cálculo do comportamento transiente do pressurizador de um reator a água pressurizada. Este trabalho segue um modela desenvolvido por S.G. Margolis e J.A. Redfield. O estudo mostra um programa digital de uma simulação da dinâmica do pressurizador, baseado- numa aplicação da 1º lei da Termodinâmica e leis de Transferência de Calor e Massa. Nenhuma hipótese é feita quanto ao particular processo termodinâmicao(processo isentrópica, processa saturada) que se segue durante um surto positivo (insurge) ou negativo (out surge). No modelo apresentado, o próprio programa determina o processo termodinâmico em cada instante do regime transiente. Dada a importância do pressurizador em relação à segurança operacional do reator do tipo a ser empregado na Central Nuclear de Angra dos Reis e, tendo em vista a utilização prática, procurou-se ajustar os dados do programa digital comparáveis aa de uma usina nuclear de 500 MWe de potência. O estudo serve também coma ferramenta de projeto mecânico do vaso pressurizador e das tubulações do circuito primário

ダイヤモンドナノ粒子の生体計測応用に関する研究

京都大学0048新制・課程博士博士(工学)甲第19002号工博第4044号新制||工||1622(附属図書館)31953京都大学大学院工学研究科分子工学専攻(主査)教授 白川 昌宏, 教授 田中 庸裕, 教授 濵地 格学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

AFIDS - architecture for fault injection in distributed systems

Sistemas distribuídos já são de amplo uso atualmente e seu crescimento tende a se acentuar devido a popularização da Internet. Cada vez mais computadores se interligam e trocam informações entre si. Nestes sistemas, requerimentos como confiabilidade, disponibilidade e desempenho são de fundamental importância para a satisfação do usuário. Estes requerimentos podem ser atendidos aproveitando-se da redundância já existente com as maquinas interligadas. Mas para atingir os requisitos de confiabilidade e disponibilidade, protocolos tolerantes a falhas devem ser construídos. Tolerância a falhas visa continuar a fornecer o serviço de algum protocolo, aplicação ou sistema a despeito da ocorrência de falhas durante a sua execução. Tolerância a falhas pode ser implementada por hardware ou por software através de mascaramento ou recuperação de falhas. Recentemente, a injeção de falhas implementada por software tem sido um dos principais métodos utilizados para validar protocolos tolerantes a falhas em sistemas distribuídos, e muitas ferramentas tem sido construídas. Contudo, não ha nenhuma biblioteca de classes orientada a objetos para auxiliar novos pesquisadores na construção da sua própria ferramenta de injeção de falhas. Este trabalho apresenta uma proposta de uma arquitetura orientada a objetos escrita em C++ para sistemas operacionais UNIX usando sockets, de modo a alcançar aquele objetivo. Esta arquitetura é chamada de AFIDS (Architecture for Fault Injection in Distributed Systems). AFIDS pretende fornecer uma estrutura básica que aborda as questões principais no processo de injeção de falhas implementada por software: a) a Geraldo de parâmetros de falhas para o experimento, b) o controle da localização, tipo e tempo da injeção de falhas, c) a coleta de dados do experimento, d) a injeção efetiva da falha e a análise dos dados coletados de modo a obter medidas de dependabilidade sobre o protocolo tolerante a falhas. Ou seja, AFIDS pretende ser um framework para a construed° de ferramentas de injeção de falhas. Segundo [BOO 961: "Através do uso de frameworks maduros, o esforço de desenvolvimento torna-se mais fácil, porque os principais elementos funcionais podem ser reutilizados". AFIDS leva em consideração várias questões de projeto que foram obtidas através da analise de oito ferramentas de injeção de falhas por software para sistemas distribuídos: FIAT [SEG 88], EFA [ECH 92. ECH 94], SFI [ROS 93], DOCTOR [HAN 93], PFI [DAW 94], CSFI [CAR 95a], SockPFI [DAW 95] e ORCHESTRA [DAW 96]. Para auxiliar a construção de AFIDS, é apresentada uma ferramenta de injeção de falhas que utiliza um objeto injetor de falhas por processo do protocolo sob teste. AFIDS e esta ferramenta são implementadas em C++ usando sockets em Linux. Para que AFIDS se tome estável e consistente e necessário que outras ferramentas sejam construídas baseadas nela. Isto é enfatizado porque, segundo [BOO 96]: "Um framework são começa a alcançar maturidade apos a sua aplicação em pelo menos três ou mais aplicações distintas".Currently, distributed systems are already in wide use. Because of the Internet popularization their growth tend to arise. More and more computers interconnect and share information. In these systems, requirements such as reliability, availability and performance are fundamental in order to satisfy the users. These requirements can be reached taking advantage of the redundancy already associated with the computers interconnected. However, to reach the reliability and availability requirements, fault tolerant protocols must be built. Fault tolerance aims to provide continuous service of some protocol, application or system in despite of fault occurrence during its execution. Fault tolerance can be implemented in hardware or software using fault masking or recovery. Recently, the software-implemented fault injection has been one of the main methods used to validate fault tolerant protocols in distributed systems, and many tools has been built. However, there is no object-oriented class library to aid new researchers on the buildin g of own fault injection tool. This work presents a proposal of an objectoriented architecture written in C++ for UNIX operating systems using sockets, in order to reach that purpose. This architecture is called AFIDS (Architecture for Fault Injection in Distributed Systems). AFIDS intends to provide a basic structure that addresses the main issues of the process of software-implemented fault injection: a) the generation of fault parameters for the experiment, b) the control of the location, type and time of the fault injection, c) the data collection of the experiment, d) the effective injection of the faults, and e) the analysis of collected data in order to obtain dependability measures about the fault tolerant protocol sob test. According to [BOO 96]: "By using mature frameworks, the effort of the development team is made even easier, because now major functional elements can be reused.". AFIDS regards various design issues that were obtained from the analysis of eight tools of software-implemented fault injection for distributed systems: FIAT [SEG 88], EFA [ECH 92, ECH 94], SFI EROS 93], DOCTOR [HAN 93], PFI [DAW 94], CSFI [CAR 95a], SockPFI [DAW 95] e ORCHESTRA [DAW 96]. In order to aid the AFIDS building, a fault injection tool that uses one injector object in each process of protocol under test is shown. AFIDS and this tool are implemented in C++ using sockets on Linux operating system. AFIDS will become stable and consistent after the building of others tools based on it. This is emphasized because, according to [BOO 96]: "A framework does not even begin to reach maturity until it has been applied in at least three or more distinct applications"

Selective Labeling of Proteins on Living Cell Membranes Using Fluorescent Nanodiamond Probes

The impeccable photostability of fluorescent nanodiamonds (FNDs) is an ideal property for use in fluorescence imaging of proteins in living cells. However, such an application requires highly specific labeling of the target proteins with FNDs. Furthermore, the surface of unmodified FNDs tends to adsorb biomolecules nonspecifically, which hinders the reliable targeting of proteins with FNDs. Here, we combined hyperbranched polyglycerol modification of FNDs with the β-lactamase-tag system to develop a strategy for selective imaging of the protein of interest in cells. The combination of these techniques enabled site-specific labeling of Interleukin-18 receptor alpha chain, a membrane receptor, with FNDs, which eventually enabled tracking of the diffusion trajectory of FND-labeled proteins on the membrane surface

Quality of service of failure detectors in the presence of message loss bursts

Orientador: Edmundo Roberto Mauro MadeiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: A Qualidade de Serviço (QoS) de detectores de defeitos determina a rapidez que um detector de defeitos q detecta a quebra de um processo p, e a precisão que q informa essa quebra. Em redes de longa distância e em redes sem fio, a ocorrência de quebras de processo, altas variações de atraso e perdas de pacotes em rajadas são comuns. Nestas condições, uma escolha adequada de parâmetros, por um configurador de detectores de defeitos, para manter o detector de defeitos satisfazendo os requisitos de QoS, é requerida. Por isso, este trabalho propõe um configurador de detector de defeitos que leva em conta a distribuição de probabilidade de comprimento de rajadas de perdas de pacotes de mensagem, através do uso de um modelo de Markov. Os resultados da simulação mostram que os parâmetros fornecidos pelo configurador proposto tendem a levar o detector de defeitos a satisfazer os requisitos de QoS em redes sujeitas a rajadas de perdas. Adicionalmente, a pesquisa mostra que é possível melhorar a precisão do detector de defeitos usando uma combinação de estimadores simples de atrasos de mensagensAbstract: The quality of service (QoS) of failure detectors determines how fast a failure detector q detects the crash of a process p, and how accurate q informs the p crash. In wide area networks and wireless networks, the occurrence of process crashes, high delay variations and burst losses in message packets are common. In these conditions, an adequate choice in the failure detector parameters, by a failure detector configurator, to keep the failure detector satisfying the QoS requirements, is required. Therefore, this work proposes a failure detector Configurator which takes into account the probability distribution of loss burst lengths of message packets, by using a Markov model. The simulation results show that the parameters provided by the proposed configurator tend to lead the failure detector to satisfy the QoS requirements in networks subject to message loss bursts. Additionally, the work shows that is possible improve the accuracy of the failure detector by using a simple combination of simple message delay estimatorsDoutoradoMestre em Ciência da Computaçã

Dpcp (discard Past Consider Present) - A Novel Approach To Adaptive Fault Detection In Distributed Systems

Fault detection is a fundamental issue for fault tolerance in distributed systems. This paper presents the DPCP (Discard Past Consider Present) approach, that discards the last elapsed times of fault detection messages and considers only the current one. By this way, DPCP allows to perform a fast, accurated and scalable adaptive fault monitoring for asynchronous distributed systems. The scalability comes from the parameter Minimum-TimeUnit, that controls the minimum frequency of the fault monitoring messages. The fastness and accuracy of fault monitoring come from the changing of timeout and monitoring interval values as soon as the system workload and the Minimum TimeUnit allow. Some DPCP experiments on ACE+TAO were made to observe DPCP behavior on changing network workloads.7682Aguilera, M.K., Chen, W., Toueg, S., (1998) Failure Detection and Consensus in the Crash-Recovery Model, , Technical Report 98-1676, Department of Computer Science, Cornell UniversityChandra, T.D., Toueg, S., Unreliable failure detectors for reliable distributed systems (1996) Journal of the ACM, 43 (2), pp. 225-267Felber, P., (1998) The CORBA Object Group Service: A Service Approach to Object Groups in CORBA, , PhD thesis, École Polytechnique Fédérale de LausanneMacêdo, R.J.A., Failure detection in asynchronous distributed systems II Test and Fault Tolerance Workshop (II WTF 2000). Curitiba, Brazil, Jul. 2000, , http://www.lasid.ufba.br/public/artigos/Narasimhan, P., Moser, L.E., Melliar-Smith, P.M., Replica consistency of CORBA objects in partitionable distributed systems (1997) Distributed Systems Engineering, 4, pp. 139-150Natarajan, B., Gokhale, A., Schmidt, D.C., DOORS: Towards high-performance fault-tolerant CORBA Proceedings of the 2nd International Symposium on Distributed Objects and Applications (DOA '00). Antwerp, Belgium, Sept. 2000, OMG(2000) Fault Tolerant CORBA Specification, , Object Management GroupAprSchmidt, D.C., Douglas C. Schmidt's Welcome Page, , http://newport.ece.uci.edu/~schmidt/Sergent, N., Défago, X., Schiper, A., Failure detectors: Implementation issues and impact on consensus performance (1999), Technical Report SSC/1999/019. École Polytechnique Fédérale de LausanneSotoma, I., Madeira, E.R.M., ADAPTATION - Algorithms to ADAPTive FAulT MonItOriNg and their implementation on CORBA Proceedings IEEE of the 3rd International Symposium on Distributed Objects and Applications (DOA'01). Rome, Italy, Sep. 2001, , (accepted for publication

Comprehensive and quantitative analysis for controlling the physical/chemical states and particle properties of nanodiamonds for biological applications

The physical/chemical states and properties of nanodiamonds subjected to thermal annealing and air oxidation, which are indispensable processes for the preparation of fluorescent nanodiamonds, were investigated. Specifically, the weight loss, particle size, crystal quality, chemical bonding states of carbon and oxygen, zeta potential, dispersibility, and fluorescent and optically detected magnetic resonance (ODMR) properties were determined using X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), elemental analysis, dynamic light scattering, Raman analysis, X-ray photoelectron spectroscopy (XPS), IR spectroscopy, and a home-made fluorescence and ODMR microscope. The study focused on small-sized nanodiamonds ([similar]50 nm), which are applicable for biological research. The obtained results should be useful for controlling the mutually-related physical/chemical states and properties of diamond nanoparticles

Effective production of fluorescent nanodiamonds containing negatively-charged nitrogen-vacancy centers by ion irradiation

Fluorescence from negatively-charged nitrogen-vacancy centers (NV[−]s) in diamonds has unique optical properties with none of the undesirable effects such as photo-bleaching and photo-blinking. In addition, the spin-dependent fluorescence intensity of NV[−]s allows us to perform optically detected magnetic resonance (ODMR) investigation for evaluating the presence of NV−s and for the electronic local environment. In this work, we irradiated H[+], He[+], Li[+] and N[+] ions to nanodiamonds with a median size of 26 nm at various irradiation energies and doses for improving the NV[−] concentration. ODMR observations of the nanodiamonds showed that ion irradiation increased the number of nanodiamonds containing NV[−]s up to 200 ppm, whereas without ion irradiation, only few NV[−]s were found. The number of nanodiamonds containing NV[−]s at various ion irradiation doses was not monotonous, but had maxima at certain irradiation doses. These results suggest a competition in two opponent roles of vacancies, effective for pairing with nitrogen atoms and as defects for developing damage in crystalline. We also found that sharp and strong ODMR signals were obtained from nanodiamonds irradiated at the optimal condition for the highest yield of NV−s. We concluded that He[+] ion irradiations with 60 or 80 keV at a dose of 1 × 10[13] ions cm[–2] are the conditions required for the most efficient production of a high quantity of nanodiamonds containing NV[−]s

Single-Step Metal-Free Grafting of Cationic Polymer Brushes on Fluorescent Nanodiamonds

Cationic polymers are often employed in conjugation with nanomaterials, and the resultant hybrids are useful for various bioapplications. Here, a single-step metal-free method for the synthesis of fluorescent nanodiamonds (FNDs) conjugated with cationic polymer brushes is reported. Distinct from the common methods such as atom transfer radical polymerization and reversible addition fragmentation chain transfer, our ring-opening-polymerization-based method is simple and less time consuming and hazardous. Infrared spectroscopy, thermogravimetric analysis, zeta potential, and dynamic light scattering confirmed the synthesis. The produced FND-polymer brushes showed markedly higher cell labeling and internalization efficiency without noticeable cytotoxicity. Our method is general and applicable to other nanoparticles as well for uses in diverse research areas