Piezoelectrically actuated time-averaged atomic microtraps

We present a scheme for creating tight and adiabatic time-averaged atom-traps through the piezoelectric actuation of nanomagnetic structures. We show that potentials formed by the circular translation of magnetic structures have several advantages over conventional rotating-field techniques, particularly for high trap frequencies. As the magnitude of the actuation is changed, the trapping potential can be changed adiabatically between harmonic 3D confinement and a toroidal trap

The Adaptive Greenhouse an Integrated Systems Approach to Developing Protected Cultivation Systems

Protected cultivation systems are used throughout the world as a powerful instrument to produce crops. They protect the crops from unfavorable outdoor climate conditions and pests and offer the opportunity to modify the indoor climate to create an environment that is optimal for crop growth and production, both in terms of quality and quantity. A quick scan of protected cultivation systems presently in use reveals that various types of protected cultivation systems have evolved in time. These cultivation systems differ for instance in terms of construction and cover materials used, the presence and use of different types of climate conditioning equipment, soil or soilless cultivation and nutrition. These differences are determined by the local climate, the availability of water, soil and water quality, the availability of capital, labor and materials and local legislation, to mention a few. With these observations in mind, this paper addresses the question of how to design a protected cultivation system that best satisfies the local conditions in the region considered. This is a multi-factorial design and optimization problem. This research aims at developing a generic design tool, using available knowledge for instance contained in heuristic and mathematical models. In this paper, the outlines of a systematic design procedure to design protected cultivation systems are sketched. The design of a minimum fossil energy greenhouse is used as example to illustrate the approac

An impact penetrometer for a landing spacecraft

The design, development and calibration of an impact force transducer or penetrometer, for use on the Huygens spacecraft scheduled to land on the surface of Saturn's moon Titan, is described, The thumb-sized transducer employs a piezoelectric sensing element and is capable of working at cryogenic temperatures. Use of the sensor on a spacecraft imposes several reliability and safety constraints, as well as the desire to minimize mass (the sensor mass is 15 g). The impact force profile, measured at 10 kHz by the sensor, allows estimation of the density and cohesion of the surface material, and its particle size distribution. Sample profiles for terrestrial materials (sand, gravel and clay) are given