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Ion irradiation and annealing experiments were performed on Cu60Zr20Hf10Ti10 bulk metallic glass (BMG) specimens to investigate their irradiation- and temperature-induced microstructural and mechanical property evolution. For the ion irradiations, samples were exposed to 9 MeV Ni3+ ions to a midrange (~1.2 μm depth) dose of 10 displacements per atom (dpa) at temperatures ranging from room temperature to 360 °C (the corresponding peak dose at ~2.8 μm depth was ~25 dpa). Bulk X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization revealed that the alloy did not crystallize during irradiation up to 290 °C but did partially crystallize at 360 °C. XRD analysis revealed that the crystallization which occurred in the sample irradiated at 360 °C was caused by thermal effects instead of irradiation displacement damage. Subsequent Rietveld refinement analysis of the XRD measurements revealed the presence of two distinct crystal phases, namely a CuTiZr hexagonal structure belonging to the P63/mmc space group and a CuTi tetragonal structure belonging to the P4/mmm space group. Nanoindentation experiments revealed that no pronounced hardness changes occurred in the specimens irradiated at room temperature and 290°C, although significant hardening was observed in the sample irradiated at 360 °C. The significant increase in the hardness at 360°C was ascribed to thermally induced partial crystallization of the alloy instead of the ion irradiation. In general, the results of the nanoindentation experiments and XRD characterization suggest that although the Cu BMG exhibits good stability during irradiation at temperatures up to 290 °C it is not suitable for irradiation environments where the temperature is 360 °C for extended periods of time. The Lam and Chong extrapolation method, which has been used to study the indentation size effect (ISE) in amorphous alloys, was employed to quantify how irradiation and temperature affect this type of behavior in the BMG. However, the poor linear fitting of the indentation hardness data by this model indicate that a new ISE model is likely needed to quantify indentation hardening in BMGs.

In this paper we present the key elements of the NICCI (Network-centric Infrastructure for Command, Control and Intelligence) infrastructure and compare and contrast them with similar capabilities provided by the OGSA (Open Grid Services Architecture) grid infrastructure. We also examine the advantages and disadvantages of using the OGSA grid infrastructure as a substrate for implementing NICCI and highlight some of the technology gaps. Finally, looking ahead at the future of the grid computing research, we identify several research thrusts where we believe there is a natural synergy and opportunity for cross-pollination between the NICCI-sponsored research and the ongoing efforts of the grid community.

Approaches and metrics useful in assuring reliable software, starting from the time at which requirements are defined, are discussed. This study provides the background for a discussion of technology and policy advances that are expected to greatly improve the ability to field the systems promised. >

The concept of operations is shifting-from large static units with fixed missions to small groups operating independently, with shifting goals. These groups need to coordinate with respect to information, goals and resources. They need to predictably interact with each other and with autonomous, distributed sensors and operational equipment. Unpredictability regarding where, when, how, and with whom we need to interact creates the need for developing open (unbounded) systems that are both flexible and predictable. The habitats concept moves the locus of control and context sensitivity from the component (or agent) level to the habitat level-for features where the components in a habitat do have common elements of control, function, and accountability. It provides the ability to easily define and evolve habitats by expressing rules and constraints in system architecture and combining enforcement with adaptability by providing authorized services through controlled extensibility-enabling capabilities.

Data from a national survey (n = 1666) of researchers, practitioners, and policymakers in the field of rural mental health services were used to conduct a sociometric analysis of person-to-person communication in tData from a national survey (n = 1666) of researchers, practitioners, and policymakers in the field of rural mental health services were used to conduct a sociometric analysis of person-to-person communication in tData from a national survey (n = 1666) of researchers, practitioners, and policymakers in the field of rural mental health services were used to conduct a sociometric analysis of person-to-person communication in the field. This article describes the structure of the person-to-person communication network in terms of its connectedness, centrality, homogeneity, and differentiation. Despite the diversity of survey respondents, and apparently meager interorganizational communication, communication in the field is similar, in many respects, to that observed in “invisible colleges.” While the probability of two randomly chosen individuals being in contact is low (0.0008), over 70% were connected indirectly. The person-to-person communication network is also highly centralized and exhibits higher than expected communication among respondents in the same professional role, type of work organization, and geographical region. It does not appear to be highly differentiated with respect to topic, since the majority of information providers are contacted with respect to a number of topi While the probability of two randomly chosen individuals being in contact is low (0.0008), over 70% were connected indirectly. The person-to-person communication network is also highly centralized and exhibits While the probability of two randomly chosen individuals being in contact is low (0.0008), over 70% were connected indirectly. The person-to-person communication network is also highly centralized and exhibits higher than expected communication among respondents in the same professional role, type of work organization, and geographical region. It does not appear to be highly differentiated with respect to topic, since the majority of information providers are contacted with respect to a number of topics.

The area of rural mental health services was used as a testbed to study information-seeking behavior in a field that includes researchers, policymakers, and practitioners. Findings from a nationwide survey (n = 1666) describe the sources that were used to obtain information about various topics and the use and value of these sources by or to individuals in various work roles and settings. The findings demonstrate the importance of person-to-person communication; differences in the sources used, and the value placed on these sources, by individuals in different work roles and settings; and that information-seeking episodes generally involve using multiple sources (5.0) to obtain information about several topics (3.2).