19,990 research outputs found
Introducing a new technology to enhance community sustainability: An investigation of the possibilities of sun spots
The introduction of the Sun SPOT, Small Programmable Object Technology, developed by Sun Microsystems has been depicted as providing a revolutionary change in cyber physical interaction. Based on Sun Java Micro Edition (ME), this sensor technology has the potential to be used across a number of discipline areas to interface with systems, the environment and biological domains. This paper will outline the potential of Sun SPOTs to enhance community sustainability. An action based research project was carried out to investigate the potential uses of these technologies and develop a prototype system as a proof of concept. The research will compare Sun SPOTs with similar technologies, provide an assessment of the technology, and propose a number of possible implementations of the technology to enhance community sustainability
Quantum theory: the role of microsystems and macrosystems
We stress the notion of statistical experiment, which is mandatory for
quantum mechanics, and recall Ludwig's foundation of quantum mechanics, which
provides the most general framework to deal with statistical experiments giving
evidence for particles. In this approach particles appear as interaction
carriers between preparation and registration apparatuses. We further briefly
point out the more modern and versatile formalism of quantum theory, stressing
the relevance of probabilistic concepts in its formulation. At last we discuss
the role of macrosystems, focusing on quantum field theory for their
description and introducing for them objective state parameters.Comment: 12 pages. For special issue of J.Phys.A, "The Quantum Universe", on
the occasion of 70th birthday of Professor Giancarlo Ghirard
Costs and benefits of multiple levels of models in MDA development
In Model-Driven Architecture (MDA) development, models of a distributed application are carefully defined so as to remain stable in face of changes in technology platforms. As we have argued previously in [1, 3], models in MDA can be organized into different levels of platformindependence. In this paper, we analyze the costs and benefits of maintaining separate levels of models with transformations between these levels. We argue that the number of levels of models and the degree of automation of transformations between these levels depend on a number of design goals to be balanced, including those of maximizing the efficiency of the design process and maximizing the reusability of models and transformations
Slow-light enhanced light-matter interactions with applications to gas sensing
Optical gas detection in microsystems is limited by the short micron scale
optical path length available. Recently, the concept of slow-light enhanced
absorption has been proposed as a route to compensate for the short path length
in miniaturized absorption cells. We extend the previous perturbation theory to
the case of a Bragg stack infiltrated by a spectrally strongly dispersive gas
with a narrow and distinct absorption peak. We show that considerable signal
enhancement is possible. As an example, we consider a Bragg stack consisting of
PMMA infiltrated by O2. Here, the required optical path length for visible to
near-infrared detection (~760 nm) can be reduced by at least a factor of 10^2,
making a path length of 1 mm feasible. By using this technique, optical gas
detection can potentially be made possible in microsystems
Recommended from our members
Kinetic calculation of rarefied gaseous flows in long tapered rectangular microchannels
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Gaseous flows in microsystems have attracted considerable attention in fluid dynamic communities
over the last few years. When the size of the device is in the range of microns, the molecular mean free path
becomes comparable with the device size, and the details of the molecular interactions need to be taken into
account. The proper description of such microflows requires the consideration of the velocity distribution
function of the molecules and kinetic equations. The scope of the present paper is to discuss the
determination of the behavior of pressure driven rarefied gas flows in microchannels at the kinetic level. As a
new application of the methodology, preliminary results are presented for pressure driven flows of single
gases through long rectangular tapered microchannels, which have constant widths but varying depths along
the axis of the channel. The kinetic calculation is based on the solution of the linearized Bhatnagar-Gross-
Krook (BGK) equation and refers to the determination of the mass flow rate through the channel and the
axial distribution of the pressure. The BGK equation is solved by the discrete velocity method. It is shown
that the mass flow rate exhibits the diodicity effect, which means that the flow rate depends on the
orientation of the channel. If the gas flows from the larger cross section towards the smaller one, the flow
rate is larger than in the opposite situation. The pressure profile strongly varies near the small cross section,
and it has a quite different character than in the case of channels with uniform cross sections. The tapered
microchannel might be useful for separating the different gaseous components in engineering applications
Dynamical Semigroup Description of Coherent and Incoherent Particle-Matter Interaction
The meaning of statistical experiments with single microsystems in quantum
mechanics is discussed and a general model in the framework of non-relativistic
quantum field theory is proposed, to describe both coherent and incoherent
interaction of a single microsystem with matter. Compactly developing the
calculations with superoperators, it is shown that the introduction of a time
scale, linked to irreversibility of the reduced dynamics, directly leads to a
dynamical semigroup expressed in terms of quantities typical of scattering
theory. Its generator consists of two terms, the first linked to a coherent
wavelike behaviour, the second related to an interaction having a measuring
character, possibly connected to events the microsystem produces propagating
inside matter. In case these events breed a measurement, an explicit
realization of some concepts of modern quantum mechanics ("effects" and
"operations") arises. The relevance of this description to a recent debate
questioning the validity of ordinary quantum mechanics to account for such
experimental situations as, e.g., neutron-interferometry, is briefly discussed.Comment: 22 pages, latex, no figure
Sensorless action-reaction-based residual vibration suppression for multi-degree-of-freedom flexible systems
This paper demonstrates the feasibility of controlling motion and vibration of a class of flexible systems with inaccessible or unknown outputs through measurements taken from their actuators which are used as single platforms for
measurements, whereas flexible dynamical systems are kept free from any attached sensors. Based on the action reaction law of dynamics, the well-known disturbance observer is used to determine the incident reaction forces from these dynamical systems on the interface planes with their actuators. Reaction
forces are considered as feedback-like signals that can be used as alternatives to the inaccessible system outputs. The sensorless action reaction based motion and vibration control technique is implemented on a flexible system with finite modes and all results are verified experimentally
- …