3,261 research outputs found
Batavia Building
No full textDetail, brick stepped arch and end of oriel-like bay over the entrance porch to the main wooden door; The client for this office building was NV Batavia Arak Maatschappij, a trading company dealing arack (or arrack, a liquor) from Jakarta (formerly Batavia) in what was then the Dutch East Indies. The building has five floors, an attic and a basement on the back, which is adjacent to the Oudezijds Kolk canal. The building also had a warehouse area. It is reinforced concrete clad with brown brick in the style of the expressionist Amsterdam School. This was unusual for Slot, who normally worked in the Hilversum area in an art nouveau (Nieuwe Kunst) style. The client may have dictated the style. The sculptors of the monkey sculptures and reliefs of elephants on the richly decorated façade are unknown, possibly Jaap Kaas, Johan Altdorf and/or Jan Trapman. It originally had stained glass, which is only preserved on the canal-side facade. Since 2001, the building is designated as a Rijksmonument, under monument protection. Source: SPQA Amsterdam [website]; http://spqa-am.blogspot.com/ (accessed 6/2/2014
Contra-directional coupling into slotted photonic crystals for spectrometric applications
No full textWe propose and demonstrate the concept of a contra-directional coupler between a W1 and a slotted photonic crystal waveguide. The bandwidth and operating wavelength of such a coupler can be controlled via its geometrical parameters, and power transfer is not periodic unlike in the more familiar codirectional case. Light of specific wavelengths can be extracted from the W1 mode into air slot modes using this design, with W1/slot coupling efficiencies of up to 99 ± 1%, and waveguide extracted coupling efficiencies of up to 51 ± 12% demonstrated experimentally. Combining several of these couplers in series, we demonstrate the spectral filtering functionality on-chip. The device therefore combines the well-known sensing function of the slotted waveguide geometry with the spectrometer function, thus uniting two essential biosensor functions in a monolithic device.Peer reviewe
General modeling of the windings for multi-phase ac machines
No full textThis paper, which deals with the winding modeling of ac multi-phase machines with a regular distribution of the stator slots, details an original matrix modeling of the stator winding. First, the properties of the balanced multi-phase windings (with integral-slot and fractional-slot patterns) are analysed. The winding function approach, one of the most common way to model the winding distribution effects on the stator rotating field, is then introduced. For multi-phase machines, it will be shown that the pole number generated by the winding distribution depends on a new parameter: the circularity index. The discrete nature of the winding, imposed by the stator slots, leads to the development of a discrete modeling of the winding obtained from sampling the winding function: two matrices, the winding function matrix and the distribution function matrix, are introduced to characterize the multi-phase winding. This matrix approach is thus a concise way to calculate the winding factors and to estimate the set of self and mutual stator inductances for smooth air gap multi-phase machines. A particularly original method of obtaining an analytical expression for the leakage mutual inductance is described. The results are validated with two experimental 5-phase PM machines by using experimental measurements and numerical simulations
Revelations. The epistle of Nathan the Wise ...
No full textAttributed to J.H. Donlevy by whom copyright was secured.Cover-title.Mode of access: Internet
Coherent control of Snell's law
No full textWe demonstrate coherent control of the generalized Snell's law in ultrathin gradient metasurfaces constructed by an array of V-shaped slot nanoantennas
Ridged cavity backed slot antenna with dielectric loading
No full textA reduced size cavity backed slot antenna, consisting of a transverse slot in the flat broadwall of a deep single ridge waveguide cavity is described. Partial dielectric loading achieves further reduction in electrical size. Moderate dielectric loss increases bandwidth (and reduces antenna gain).Articl
Thin-slot and thin-arm planar spiral antenna operated with and without a ground-plane
No full textMost planar spiral antennas are made as complementary structures, i.e. with equal slot and arm widths. This paper is a study of the properties of the thin-slot and thin-arm spiral where the slot is respectively narrower or greater than the spiral arm, and includes results for free space and in the presence of a ground plane. A numerical study is conducted for a range of arm-to-slot ratios, from 5% to 95% where 50% is the complementary case. The results show that changing the arm-to-slot ratio can be used to vary the input impedance, but that the thin-arm case is of limited practical value. Results are compared to theoretical expectations and independent numerical results. As an introduction a discussion on the band theory and a physical insight into the power flow near the antenna is presented.Conference Pape
DIELECTRIC LOADING OF A SMALL RIDGED CAVITY-BACKED SLOT ANTENNA.
No full textThe effects are studied of dielectric loading on the frequency of operation, input impedance, and aperture field distribution of a ridged, cavity-backed slot antenna. The transverse slot is cut in the flat broadwall of a deep, single-ridge waveguide cavity, when the cavity is excited by the center conductor of a coaxial transmission line. The role of the input-probe position in matching the antenna is demonstrated. The experimental parameters are summarized in tabular form. It is concluded that dielectric loading reduces the operating frequency and improves the slot aperture efficiency. The input impedance level is controlled by the probe position. A lossy dielectric increases bandwidth (reduces Q) at the expense of efficiency.Conference Pape
Telling stories: a metagame description of a conflict
No full textThis paper describes the use of metagame analysis to describe and explore a conflict situation. The analysis was carried out by the author, who was associated with one of the parties in the conflict, for his own benefit. A full description of the analysis is provided. A particular characteristic of the situation was that it was not possible to specify preferences for scenarios for any of the actors with a reasonable degree of confidence. This made the standard metagame analysis approach unworkable, and an alternative approach, involving the development of stories describing a variety of possible future events, was used instead
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