Elastic suspension of a wind tunnel test section

Experimental verification of the theory describing arbitrary motions of an airfoil is reported. The experimental apparatus is described. A mechanism was designed to provide two separate degrees of freedom without friction or backlash to mask the small but important aerodynamic effects of interest

Beam Diffraction by a Planar Grid Structure at 93 GHz

The idea of using diode grids for electronic beam steering was introduced by Lam et al [l]. As shown in Figure 1, when an incident beam reflects off the diode grid, the direction of the reflected wave can be controlled by progressively varying the ref1ection phase across the grid. The reflection phase of the diode grid can be controlled by varying the DC bias on the diodes. Later, a monolithic diode grid was fabricated with l600 varactor diodes, and a relative phase shift of 70° at 93 GHz was measured [2]. This work verified the transmission-line theory used to design the grid, but the phase shift was not sufficient to steer the beam, recently, Johansson [3] designed and built a passive planar grating reflector antenna that focused a beam. A rigorous moment-method solution was applied to choose a grating geometry to select the first-order diffracted wave. In this work, using the transmission-line model approach, the goal was to demonstrate that the beam can be steered by building a grid structure without diodes to give a fixed beam shift. In these grids, diodes were replaced by gaps with different sizes to obtain different capacitances needed to steer a beam at 93 GHz. The result show a successful beam shift of 30° with a loss of 2.5 dB

Caging Mechanism for a drag-free satellite position sensor

A disturbance compensation system for satellites based on the drag-free concept was mechanized and flown, using a spherical proof mass and a cam-guided caging mechanism. The caging mechanism controls the location of the proof mass for testing and constrains it during launch. Design requirements, design details, and hardware are described

A 100-element planar Schottky diode grid mixer

The authors present a Schottky diode grid mixer suitable for mixing or detecting quasi-optical signals. The mixer is a planar bow-tie grid structure periodically loaded with diodes. A simple transmission line model is used to predict the reflection coefficient of the grid to a normally incident plane wave. The grid mixer power handling and dynamic range scales as the number of devices in the grid. A 10-GHz 100-element grid mixer has shown an improvement in dynamic range of 16.3 to 19.8 dB over an equivalent single-diode mixer. The conversion loss and noise figure of the grid are equal to those of a conventional mixer. The quasi-optical coupling of the input signals makes the grid mixer suitable for millimeter-wave and submillimeter-wave applications by eliminating waveguide sidewall losses and machining difficulties. The planar property of the grid potentially allows thousands of devices to be integrated monolithically

A 10 GHz Quasi-Optical Grid Amplifier Using Integrated HBT Differential Pairs

We report the fabrication and testing of a 10 GHz grid amplifier utilizing sixteen GaAs chips each containing an HBT differential pair plus integral bias/feedback resistors. The overall amplifier consists of a 4x4 array of unit cells on an RT Duroid™ board having a relative permittivity of 2.2. Each unit cell consists of an emitter-coupled differential pair at the center, an input antenna which extends horizontally in both directions from the two base leads, an output antenna which extends vertically in both directions from the two collector leads, and high inductance bias lines. In operation, the active grid array is placed between a pair of crossed polarizers. The horizontally polarized input wave passes through the input polarizer and couples to the input leads. An amplified current then flows on the vertical leads, which radiate a vertically polarized amplified signal through the output polarizer. The polarizers serve dual functions, providing both input-output isolation as well as independent impedance matching for the input and output ports. The grid thus functions essentially as a free-space beam amplifier. Calculations indicate that output powers of several watts per square centimeter of grid area should be attainable with optimized structures

Proteoglycans support proper granule formation in pancreatic acinar cells

ArticleCopyright © Springer-Verlag Berlin Heidelberg 2015Zymogen granules (ZG) are specialized organelles in the exocrine pancreas which allow digestive enzyme storage and regulated secretion. The molecular mechanisms of their biogenesis and the sorting of zymogens are still incompletely understood. Here, we investigated the role of proteoglycans in granule formation and secretion of zymogens in pancreatic AR42J cells, an acinar model system. Cupromeronic Blue cytochemistry and biochemical studies revealed an association of proteoglycans primarily with the granule membrane. Removal of proteoglycans by carbonate treatment led to a loss of membrane curvature indicating a supportive role in the maintenance of membrane shape and stability. Chemical inhibition of proteoglycan synthesis impaired the formation of normal electron-dense granules in AR42J cells and resulted in the formation of unusually small granule structures. These structures still contained the zymogen carboxypeptidase, a cargo molecule of secretory granules, but migrated to lighter fractions after density gradient centrifugation. Furthermore, the basal secretion of amylase was increased in AR42J cells after inhibitor treatment. In addition, irregular-shaped granules appeared in pancreatic lobules. We conclude that the assembly of a proteoglycan scaffold at the ZG membrane is supporting efficient packaging of zymogens and the proper formation of stimulus-competent storage granules in acinar cells of the pancreas.German Research FoundationPortuguese Foundation for Science and Technology (FCT

A 6.5 GHz-11.5 GHz source using a grid amplifier with a twist reflector

The authors have constructed and tested an oscillator using a grid amplifier with external feedback from a twist reflector. The twist reflector serves two functions; it changes the output polarization to match the input, and its position sets the feedback phase. This permits a wider tuning range than has been possible with previous grid oscillators. The source could be continuously tuned from 8.2 GHz to 11.0 GHz by moving the twist reflector. By moving the polarizer and mirror in the twist reflector independently, a 1.8-to-1 frequency range from 6.5 GHz to 11.5 GHz was achieved. The peak effective radiated power was 6.3 W at 9.9 GHz

Farming Systems in the Pastoral Zone of NSW: An Economic Analysis

A ‘broad brush’ picture of farming in the pastoral zone of NSW is presented in this report. The pastoral zone of NSW is characterised by wide variations in climatic conditions, soil type and vegetation species. Hence representative faming system analysis was conducted for three sub-regions - the Upper Darling, the Murray-Darling and Far West. The regions were defined and described in terms of their resources, climate and the nature of agriculture. The main enterprises that farmers choose between were described and whole farm budgets and statements of assets and liabilities for the representative farms were developed. The representative farm models were used to compare traditional Merino based sheep enterprises with alternative sheep enterprises where meat was an important source of income. We found that the farming systems that have evolved in these areas are well suited to their respective environments and that the economic incentives to switch to more meat focussed sheep enterprises were not strong.Western Division, farming systems, economic, analysis, New South Wales, Farm Management, Land Economics/Use, Livestock Production/Industries, Production Economics, Research and Development/Tech Change/Emerging Technologies, Q160,