Strain-induced corrosion cracking of low-alloy steels in LWR systems — case histories and identification of conditions leading to susceptibility

The term “strain-induced corrosion cracking” (SICC) is introduced to describe crack formation involving dynamic straining, but in the absence of obvious, cyclic loading. Its origins in slow-strain-rate testing and in corrosion failures in boiler systems are described and the links with “classical” stress corrosion cracking and low-cycle corrosion fatigue are identified. Four areas, in which SICC of low-alloy steels in LWR systems has occurred, are described in detail and the typical features are used, together with literature data from laboratory testing, to identify conditions leading to susceptibility. Indications are given of remedial measures and of areas in which further work is necessary.     

On time-triggered and event-based control of integrator systems over a shared communication system

When analyzing networked control systems, where the control loop is closed over a communication system, it is crucial to take the communication system into account. Hence, time-triggered and event-based control of an integrator system with noise over a shared communication system is analyzed. Thereby, analytical models of different communication systems are used and the analysis is focused on the effect of the communication system on the performance, as well as the interaction between control and communication. For time-triggered control, where the event times are known in advance, a deterministic communication protocol can be used. Hence, time-triggered control with the two most well-known deterministic communication protocols, time division multiple access (TDMA) and frequency division multiple access (FDMA), is analyzed. For event-based control, where the events appear at random times, a contention-based communication protocol should be used. Hence, event-based control is analyzed with different contention-based communication protocols: pure ALOHA, slotted ALOHA, a queueing system, and Erlang’s loss model. It turns out that time-triggered control with either TDMA or FDMA outperforms event-based control with pure or slotted ALOHA. However, event-based control with a properly designed queueing system gives an even better performance. Thus, we conclude that it is crucial to take the details of the communication system into account.     

Die Innovationstätigkeit der deutschen Softwareindustrie

In this article we present the results of two empirical studies focusing on the structure and extent of the innovation activities of the German Software Industry and analyze distinctive features of Software Innovations. We distinguish the activities of the primary (core) Software Industry and secondary industries such as Mechanical and Electrical Engineering, Motor Industry and Telecommunications. A special focus is put on the question if innovations in Software are sequential, on the role of Open Source Software and the importance of interoperability.     

Standard-relevant publications: evidence,processes and influencing factors

Scientometrics - This paper introduces the concept of standard-relevant publications, complementary to standard-essential patents and framed by the concept of knowledge utilization. By analyzing...     

Methods for estimating strain in structures - conditions and definitions

Analyses of the impact of actual earthquakes on industrial plants and experimental investigations simulating earthquakes and pressure surges show that loads can be sustained without damage, which are according to the existing design rules far beyond the allowable limit and which cannot be calculated realistically assuming linear-elastic material behaviour according to plastic deformation. To rely on the existing capability to absorb large amounts of energy, it is necessary to have models for describing their behaviour in the plastic range taking into account the plastic deformation volume and the strain values reached.Especially for the calculation of piping systems under loads with a small probability of occurrence, the main parameters for describing the energy dissipated and the additional strain in comparison to the strain in a straight pipe are described, independent of the calculation method used (simplified or elasto-plastic time integration).In addition, strain categories and the individual strain category responsible for the integrity of the overall system are defined.     

A high-flux accelerator-based neutron source for fusion technology and materials testing

Advances in high-current linear-accelerator technology since the design of the Fusion Materials Irradiation Test (FMIT) Facility have increased the attractiveness of a deuteriumlithium neutron source for fusion materials and technology testing. This paper discusses the conceptual design of such a source that is aimed at meeting the near-term requirements of a high-flux high-energy International Fusion Materials Irradiation Facility (IFMIF). The concept employs multiple accelerator modules providing deuteron beams to two liquid-lithium jet targets oriented at right angles. This beam/target geometry provides much larger test volumes than can be attained with a single beam and target and produces significant regions of low neutron-flux gradient. A preliminary beam-dynamics design has been obtained for a 250-mA reference accelerator module. Neutron-flux levels and irradiation volumes were calculated for a neutron source incorporating two such modules, and interaction of the beam with the lithium jet was studied using a thermal-hydraulic computer simulation. Approximate cost estimates are provided for a range of beam currents and a possible facility staging sequence is suggested.This work was supported by Los Alamos National Laboratory Program Development Funds under the auspices of the U.S. Department of Energy.Supported in part by an appointment to the U.S. DOE Fusion Energy Postdoctoral Research Program administered by Oak Ridge Associated Universities.     

Carboxylic ester hydrolase and amylase in ischemic pancreatitis in the guinea pig

OBJECTIVES: To define the clinical, neuropsychological, and radiological features of bilateral parietal lobe atrophy. METHODS: Four patients underwent a comprehensive longitudinal neuropsychological assessment, as well as MRI and HMPAO-SPECT. RESULTS: The consistent findings in the patients were early visuospatial problems, agraphia of a predominantly peripheral (or apraxic) type, and difficulty with bimanual tasks, all of which outweighted deficits in memory and language until later in the course of the illness. As the disease progressed, impairments in the phonological aspects of language and in auditory-verbal short term memory were often striking, perhaps reflecting spread from the parietal lobe to perisylvian language areas. Three patients went on to develop a global dementia and fulfilled the criteria for a clinical diagnosis of probable Alzheimer's disease; the fourth patient has only recently been identified. Neuroimaging disclosed bilateral parietal lobe atrophy (MRI) and hypoperfusion (SPECT), which was out of proportion to that seen elsewhere in the brain. One patient has died and had pathologically confirmed Alzheimer's disease with particular concentration in both superior parietal lobes. CONCLUSIONS: Bilateral biparietal atrophy is a recognisable clinical syndrome which can be the presenting feature of Alzheimer's disease. Although the label "posterior cortical atrophy" has been applied to such cases, review of the medical literature suggests that this broad rubric actually consists of two main clinical syndromes with features reflecting involvement of the occipitotemporal (ventral) and biparietal (dorsal) cortical areas respectively.     

Are firms withdrawing from basic research? An analysis of firm-level publication behaviour in Germany

Scientometrics - Previous research has expressed concerns about firms engaging less in basic research. We contribute to this debate by studying trends in the scientific publishing activities of...     

一种基于盲信号提取的同频干扰抵消算法

为了抵消数字通信中的同频干扰,提出了一种基于单信道盲信号提取算法。不同于现有的盲信号提取盲分离模型,本文的模型除了利用数字信号过采样特性,还充分考虑了载波频率以及信道噪声的影响。并结合调制信号的恒模特性,提出了基于广义峭度的恒模盲信号提取算法。最后通过实验结果证实算法的有效性和稳定性。     

Gefügebesonderheiten des artgleichen Schweißgutes des hochwarmfesten Werkstoffes X 20 Cr MoV 121

Einfluß der Wärmeführung (Zwischenabkühltemperatur, Anlaßbehandlung) nach dem Schweißen auf den Gefügezustand des X 20 CrMoV 121-artgleichen Schweißgutes. Lichtmikroskopische Untersuchung von (δ-Ferrit und in Martensit umgewandeltem Restaustenit nach einmaligem Anlassen des Schweißgutes sowie nach einer anschließenden Langzeitauslagerung (bei 550°C) bzw. einer zweiten Anlaßbehandlung (bei 760°C).