Alien Registration- Hayman, Beatrice F. (Augusta, Kennebec County)

https://digitalmaine.com/alien_docs/19093/thumbnail.jp

A comprehensive approach to broadband characterization of soft ferrites

We present and discuss methods, setups, and results concerning the characterization of Mn-Zn and Ni-Zn ferrites in the frequency range DC-1 GHz, by which we bring to light the physical mechanisms responsible for the observed frequency behavior of magnetic losses W and permeability mu and provide thorough assessment of the broadband response of the material. A comprehensive array of polarization J(p) and frequency f values is investigated. A fluxmetric approach is applied up to a few MHz, which is substituted by a transmission line method at higher frequencies, up to 1 GHz. The fluxmetric measurements are made at defined J(p) value, typically from a few mT to some hundred mT. The waveguide characterization, centered on the use of a network analyzer, is instead made under defined exciting power. But a full experimental W(J(p), f) matrix up to 1 GHz and J(p) values typically belonging to the Rayleigh region is in any case retrieved, thanks to the linear response of the material at high-frequencies. Disaccommodation measurements are the route followed in these experiments to separate the rotations from the domain wall process at all frequencies. Whatever the magnetization mode, the role of eddy currents in Mn-Zn ferrite losses is put in evidence by means of resistivity measurements and ensuing multiscale numerical modeling, the loss experiments being made on progressively thinned ring samples. It is concluded that an eddy current free W(J(p), f) behavior can always be obtained, which can be decomposed into domain wall and rotation related contributions. The latter can be calculated assuming a suitable distribution of the effective internal anisotropy fields and its introduction in the Landau-Lifshitz-Gilbert derivation of the rotational susceptibility

How to revitalise a historic district: A stakeholders-oriented assessment framework of adaptive reuse

This research proposes an application of a MultiCriteria Decision Analysis (MCDA) in the adaptive reuse framework, which is able to structure the complex decision process required for the effective reuse of an historic district. Nowadays, many cities are facing an economic, financial, social and urban decline. This is particularly true when thinking about historic districts, which are usually characterized by high unique cultural values but, at the same time, show difficult characteristics in terms of comfort and security. Accordingly, the planning rules to be applied to the historic districts need to be re-written overcoming the traditional logics. The proposed adaptive reuse framework deals with the application of the Macbeth method. To properly test, develop and illustrate the framework we conducted an experimental validation through a case study: the urban regeneration of an historical district in Biella (Italy) starting from the adaptive reuse of an historic buildin

Adaptive Sampling Using Fleets of Gliders in the Presence of Fixed Buoys: a Prototype Built Upon the MyOcean Service

In the last decade the use of fleets of gliders has proven to be an effective way for sampling the ocean for long-duration missions (order of months). In a previous study [1] a method for adaptive sampling the ocean using fleets of gliders based on the use of a clustering algorithm has been introduced. The key ideas were: i) build a 2D mesh grid over the synoptic uncertainty of the ocean field to sample with “knots” having density proportional to the level of the uncertainty; ii) group this set of knots using a clustering algorithm, i.e. the Fuzzy C-Means (a fuzzy variant of the well-known K-Means algorithm). The centroids are the next way-points for the gliders. However, that method assumed all-maneuverable assets. In this study we extend it by exploiting the existence of non-maneuverable assets, i.e. fixed buoys (a situation that frequently occurs in real scenarios) and by considering time-dependent uncertainty, i.e. aiming to reach the way-points at time t such that the uncertainty at future times is minimized. The first essential idea is to consider the positions of fixed buoys as part of the centroids to obtain from the clustering algorithm: the remaining centroids to be computed will be considered as the next positions where to send each glider. By using the clustering algorithm described in [2], called “Partially Provided Centroids Fuzzy C-Means” (PPC-FCM), we have been able to exploit the presence of fixed buoys by sending the gliders in regions not already covered by the buoys/floats. This allows a better distribution (lower overlapping) of the sensing assets, with respect to the direct use of the standard Fuzzy C-Means, uninformed of the presence of the buoys. The second idea is to replace the synoptic uncertainty field by the field of mutual information between the way points at time t and a selected future time. We have built a prototype of this novel adaptive sampling scheme for mixed assets (maneuverable and non-maneuverable) that automatically retrieves ocean forecasts (currents, temperature, salinity, etc.) from MyOcean services. In addition, the prototype comes with a graphical user interfaces that facilitates the selection of the region of interest for data download. Once the data have been downloaded with low efforts, the (PPC-FCM) algorithm is run to get the next gliders way-points. The procedure is then repeated any time new forecasts are available. Our tool will be even more effective if MyOcean forecast products in future releases contain, other than the expected (mean) value of the field of interest obtained from forecasting models, a measure of the associated uncertainty, such as standard deviations. By including this uncertainty estimate, glider mission planners would have valuable information on where to send the assets in order to reduce the uncertainty as much as possible. REFERENCES [1] Cococcioni, et. al., «SONGs: Self Organizing Network of Gliders for Adaptive Sampling of the Ocean», Maritime Rapid Environmental Assessment Conference, October 18-22, Lerici, Italy, 2010 [2] Cococcioni, «Clustering in the presence of partially provided centroids: a fuzzy approach», Technical Report, Department of Information Engineering, Pisa, 2014

Student Mobility in the Nation\u27s Elementary Schools

Children who change schools frequently face many challenges to their success in school

FEASIBILITY OF A BRAYTON CYCLE AUTOMOTIVE AIR CONDITIONING SYSTEM

The goal of this work is to develop a preliminary analysis on the feasibility of using an alternative automotive air conditioning system based on the Brayton cycle, to be assembled using a turbocompression-intercooling system configuration available in the market. The first step of the analysis was a thermodynamic study to define the system capacity and parameters for selecting the system components. The next step was to select from turbocompressor maps a suitable model for the application, and to determine pressures/temperatures throughout the system in order to evaluate intercooler capacity and select a suitable model available in the market. The impact of the turbocompression system was also analyzed in engine performance. The proposed turbocompression system requires 1,7 kW from the engine, which is very similar to a conventional air conditioning system requirement. In terms of weight, this preliminary analysis indicated that the proposed system is about 1,0 kg heavier than the conventional system. The analysis indicated that the alternative system is about 56% more expensive than the conventional one, but on the other hand presents a 24% lower maintenance cost . Considering the results of the preliminary analysis, the proposed system is technically feasible for application in automotive air conditioning, but requires a design optimization process in order to reduce its weight and initial costs, which might allow lower maintenance costs to payback the alternative system

Magnetic Losses in Soft Ferrites

We review the basic phenomenology of magnetic losses from DC to 1 GHz in commercial and laboratory-prepared soft ferrites considering recent concepts regarding their physical interpretation. This is based, on the one hand, on the identification of the contributions to the magnetization process provided by spin rotations and domain walls and, on the other hand, the concept of loss separation. It additionally contemplates a distinction between the involved microscopic dissipation mechanisms: spin damping and eddy currents. Selected experimental results on the broadband behavior of complex permeability and losses in Mn-Zn ferrites provide significant examples of their dependence on sintering methods, solute elements, and working temperature. We also highlight the peculiar frequency and temperature response of Ni-Zn ferrites, which can be heavily affected by magnetic aftereffects. The physical modeling of the losses brings to light the role of the magnetic anisotropy and the way its magnitude distribution, affected by the internal demagnetizing fields, acts upon the magnetization process and its dependence on temperature and frequency. It is shown that the effective anisotropy governs the interplay of domain wall and rotational processes and their distinctive dissipation mechanisms, whose contributions are recognized in terms of different loss components

Subsidized food consumption systems in low income countries : the Pakistan experience

"#2063"--handwritten on coverIncludes bibliographical reference