Journal of Research of the National Institute of Standards and Technology最新文献

We present scalable first hitting time methods for finding a collection of nodes that enables the fastest time for the spread of consensus in a network. That is, given a graph G = (V, E) and a natural number k, these methods find k vertices in G that minimize the sum of hitting times (expected number of steps of random walks) from all remaining vertices. Although computationally challenging for general graphs, we exploited the characteristics of real networks and utilized Monte Carlo methods to construct fast approximation algorithms that yield near-optimal solutions.

Additive manufacturing (AM) with cement-based materials is an emerging technology that has the potential to revolutionize concrete construction. The placement process is quite complex, requiring suffcient flow properties as the material leaves the nozzle, and suffcient stiffening properties before the subsequent layer is placed. Precise control of material proportions and in-line monitoring of the time-dependent rheology are required to ensure the successful adoption of AM in the concrete construction community. To facilitate the study of the rheological properties of cementitious materials, as they pertain to AM, a commercial bench-top fused filament fabrication three-dimensional (3-D) printer was modifed to dispense cement paste mixtures. Modifcations included the design and assembly of a pumping system and software modifcations to the 3-D printer's firmware that were necessary to accommodate the new hardware. After assembly, a series of tests were conducted to verify machine movements and to calibrate the number of step pulses required per unit volume of extruded paste. The resulting software modifications and configuration files are publicly available.

In Science-The Endless Frontier, Vannevar Bush wrote that reaping the potential benefits of science conducted at federal laboratories requires the discoveries made in the laboratories be transferred to society. In federal laboratories, Offices of Research and Technology Applications (ORTAs) are tasked with transferring laboratory-developed technologies to the market, allowing society to reap the benefits provided by scientific investments. In fiscal year 2016, the Technology Partnerships Office of the National Institute of Standards and Technology (NIST) conducted a first-of-its-kind survey of the ORTAs of more than 50 federal laboratories to obtain information on their organization and operation. We present descriptive analyses of the responses to this survey in two topical areas: organizational characteristics and technology transfer characteristics. We disaggregated the data across the dimension of budget size to describe similarities and differences in responses across the budget categories. Among the relationships we observed, we found that ORTAs with larger technology transfer budgets report higher frequencies of conducting internal technology transfer activities, such as patent prosecution (e.g., drafting patents, filing patent applications, and responding to actions from the patent office) and market analysis. Additionally, we provide context to the data by summarizing the relevant research on ORTAs at universities, and we present potential inferences that may be drawn from that body of research and applied to the data on ORTAs at federal laboratories.

A computationally fast Fortran 90+ quadruple precision portable parallel GRSDEP (generalized real symmetric-definite eigenvalue problem) package suitable for large (80,000 x 80,000 or greater) dense matrices is discussed in this paper.