5,285 research outputs found
Fiber-modified polyurethane foam for ballistic protection
Closed-cell, semirigid, fiber-loaded, self-extinguishing polyurethane foam material fills voids around fuel cells in aircraft. Material prevents leakage of fuel and spreading of fire in case of ballistic incendiary impact. It also protects fuel cell in case of exterior fire
Fire retardant foams developed to suppress fuel fires
Heat insulating polyurethane foam retards and suppresses fuel fires. Uniformly dispersed in the foam is a halogenated polymer capable of splitting off hydrogen halide upon heating and charring of the polyurethane
Intumescent Coatings as Fire Retardants
Fire-retardant paint, when activated by the heat of fire, reacts to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction
Understanding the Process of Information Technology Implementation
Research concerned with the implementation of information technology (IT) in organizations can be divided, roughly, into two streams: factor, or variance studies; and process studies (Markus and Robey, 1988). The great majority of work has adopted a variance approach where several factors that are likelyto be associated with successful IT implementation are identified, made operational, and then tested, usually using a cross-sectional design, with statistical methods. In reviewing these studies, Lucas (1981) notes that although some 150 factors have beenidentified, only a relatively few, limited to top management support and user involvement , are consistently associated with successful implementation. In addition, researchers tend to create new factor models rather than extending and confirming the most promising existing models, and no integrated model has emerged that explains a reasonable portion of the variance in implementation outcomes (although Lucas, Ginzberg and Schultz, 1990, made a valiant attempt in this regard). Process studies, on the other hand, seek to understand the process by which IT is implemented in organizations, using interpretive techniques based on interview, observational, and collected data. Although there are relatively few process studies, they are particularly appropriatefor theory building (Glaser and Strauss, 1967). Markus and Robey (1988) have pointed to the need for more process studies of technology implementation. In this paper we describe an ongoing process study of IT implementation in five settlement houses in New York City, using an action research approach (Argyris et. al., 1985). Settlement houses are the primary way that social services are delivered to community members of inner cities. From a research perspective, the IT implementation in the settlement houses is important in several respects. First, while IT implementations in profit-seeking firms have been widely researched, relatively few studies have been conducted in not-for-profit businesses. Not-for-profit firms are likely to differ from their profit-seeking counterparts in terms of their organizational values, goals, reward and control structures of individuals, organizational processes, staffing, environmental influences, and acquisition of resources. Second, few existing studies address the dynamicsinvolved in implementing IT in a group of cooperating, autonomous organizations. Our implementation study involves a confederation of five settlement houses and United Neighborhood Houses of NYC (UNH), an organization which provides technical assistance to the houses. This confederation is analogous in structure to IT partnerships and alliances, which have become popular among businesses in the for-profit secto
Development and testing of a risk indexing framework to determine field-scale critical source areas of faecal bacteria on grassland.
This paper draws on lessons from a UK case study in the management of diffuse microbial pollution from grassland farm systems in the Taw catchment, south west England. We report on the development and preliminary testing of a field-scale faecal indicator organism risk indexing tool (FIORIT). This tool aims to prioritise those fields most vulnerable in terms of their risk of contributing FIOs to water. FIORIT risk indices were related to recorded microbial water quality parameters (faecal coliforms [FC] and intestinal enterococci [IE]) to provide a concurrent on-farm evaluation of the tool. There was a significant upward trend in Log[FC] and Log[IE] values with FIORIT risk score classification (r2 =0.87 and 0.70, respectively and P<0.01 for both FIOs). The FIORIT was then applied to 162 representative grassland fields through different seasons for ten farms in the case study catchment to determine the distribution of on-farm spatial and temporal risk. The high risk fields made up only a small proportion (1%, 2%, 2% and 3% for winter, spring, summer and autumn, respectively) of the total number of fields assessed (and less than 10% of the total area), but the likelihood of the hydrological connection of high FIO source areas to receiving watercourses makes them a priority for mitigation efforts. The FIORIT provides a preliminary and evolving mechanism through which we can combine risk assessment with risk communication to end-users and provides a framework for prioritising future empirical research. Continued testing of FIORIT across different geographical areas under both low and high flow conditions is now needed to initiate its long term development into a robust indexing tool
Interpretation and the Constraints on International Courts
This paper argues that methodologies of interpretation do not do what they promise – they do not constrain interpretation by providing neutral steps that one can follow in finding out a meaning of a text – but nevertheless do their constraining work by being part of what can be described as the legal practice
Aberrational Effects for Shadows of Black Holes
In this paper, we discuss how the shadow of a Kerr black hole depends on the
motion of the observer. In particular, we derive an analytical formula for the
boundary curve of the shadow for an observer moving with given four-velocity at
given Boyer--Lindquist coordinates. We visualize the shadow for various values
of parameters.Comment: 12 pages, 3 figures; Proceedings of the 524. WE-Heraeus-Seminar held
at the Physikzentrum, Bad Honnef, Germany, 17.--23.2.201
Structure of W3(OH) from Very High Spectral Resolution Observations of 5 Centimeter OH Masers
Recent studies of methanol and ground-state OH masers at very high spectral
resolution have shed new light on small-scale maser processes. The nearby
source W3(OH), which contains numerous bright masers in several different
transitions, provides an excellent laboratory for high spectral resolution
techniques. We present a model of W3(OH) based on EVN observations of the
rotationally-excited 6030 and 6035 MHz OH masers taken at 0.024 km/s spectral
resolution. The 6.0 GHz masers are becoming brighter with time and show
evidence for tangential proper motions. We confirm the existence of a region of
magnetic field oriented toward the observer to the southeast and find another
such region to the northeast in W3(OH), near the champagne flow. The 6.0 GHz
masers trace the inner edge of a counterclockwise rotating torus feature.
Masers at 6030 MHz are usually a factor of a few weaker than at 6035 MHz but
trace the same material. Velocity gradients of nearby Zeeman components are
much more closely correlated than in the ground state, likely due to the
smaller spatial separation between Zeeman components. Hydroxyl maser peaks at
very long baseline interferometric resolution appear to have structure on
scales both smaller than that resolvable as well as on larger scales.Comment: 21 pages using emulateapj.cls including 16 figures and 2 tables,
accepted to Ap
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