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p. 546-556
Received: 25 April 2006 / Accepted: 13 June 2006 / Published: 15 June 2006
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| Download PDF Full-text (176 KB) Abstract: To achieve dynamic error compensation in CNC machine tools, a non-contactlaser probe capable of dimensional measurement of a workpiece while it is being machinedhas been developed and presented in this paper. The measurements are automatically fedback to the machine controller for intelligent error compensations. Based on a well resolvedlaser Doppler technique and real time data acquisition, the probe delivers a very promisingdimensional accuracy at few microns over a range of 100 mm. The developed opticalmeasuring apparatus employs a differential laser Doppler arrangement allowing acquisitionof information from the workpiece surface. In addition, the measurements are traceable tostandards of frequency allowing higher precision.
p. 557-577
Received: 18 April 2006 / Accepted: 13 June 2006 / Published: 15 June 2006
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| Download PDF Full-text (416 KB) Abstract: With the ever increasing complex sensing and actuating tasks in manufacturingplants, intelligent sensors cluster in hybrid networks becomes a rapidly expanding area.They play a dominant role in many fields from macro and micro scale. Global object controland the ability to self organize into fault-tolerant and scalable systems are expected for highlevel applications. In this paper, new structural concepts of intelligent sensors and networkswith new intelligent agents are presented. Embedding new functionalities to dynamicallymanage cooperative agents for autonomous machines are interesting key enablingtechnologies most required in manufacturing for zero defects production.
p. 578-592
Received: 29 March 2006 / Accepted: 14 June 2006 / Published: 16 June 2006
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| Download PDF Full-text (290 KB) Abstract: A fiber optic sensor for Volatile Organic Compounds (VOCs) detection has beendeveloped and characterized for some organic gasses. The sensor is based on a novelvapochromic material, which is able to change its optical properties in presence of organicvapors in a reversely way. A nano Fabry Perot is constructed onto a cleaved ended opticalfiber pigtail by Electrostatic Self Assembly method (ESA), doping this structure with thevapochromic material. Employing a reflection scheme, a change in the intensity modulatedreflected signal at 850 nm have been registered. The response of the sensor has beenevaluated for five different VOCs, and a deeper study has been made for vapors of threedifferent alcohols.
(This article belongs to the Special Issue
Gas Sensors )
p. 593-615
Received: 21 March 2006 / Accepted: 13 June 2006 / Published: 22 June 2006
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| Download PDF Full-text (272 KB) Abstract: In view of the chiral nature of many bio-molecules (and all bio-macromolecules),most of therapeutically active compounds which target these molecules need to be chiraland “good handed” to be effective. In addition to asymmetric synthetic and separationmethodologies, enantioselective chemical sensors, able to distinguish between twoenantiomers of the same molecule, are of relevance. In order to design these sensing tools,two major classes of enantioselective layers have been developed. The first is based onmolecularly imprinted polymers which are produced (polymerized) in the presence of theirtarget, thus the polymeric material keep in “memory” the size and the shape of this moleculeand the system could be used for sensing (not reviewed here). The second approach makesuse of sensitive layers containing chiral macrocyclic receptors able of stereoselectivemolecular recognition; these receptors are mainly based on cyclodextrins. In thiscontribution, are reviewed achievements in the use of native or chemically modifiedcyclodextrins for chiral sensing purposes (at interfaces). Potentialities of other chiralmacrocycles based on calixarenes, calix-resorcinarenes or crown-ethers as supramolecularreceptors for enantioselective sensing are discussed.
p. 616-619
Received: 1 February 2006 / Published: 23 June 2006
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| Download PDF Full-text (31 KB) Abstract: n/a
p. 620-642
Received: 22 August 2005 / Accepted: 22 June 2006 / Published: 22 June 2006
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| Download PDF Full-text (132 KB) Abstract: The use of a nadir altimeter radar with a rotating knife-beam antenna pattern isconsidered for improved measurements of the sea surface wind and wave parameters over awide swath. Theoretical calculations suggest the antenna beam rotating about the verticalaxis is able to provide wide swath of order 250-350 km. Processing of the signals using timeor Doppler sampling techniques results in the division of the antenna footprint intoelementary scattering cells of the order of 14x14 km. The theoretical algorithms developedhere indicate that the system may be used to retrieve the variance of large-scale slopes, thedirection of wave propagation and the wind speed in each cell. The possibility of measuringsignificant wave height is also analyzed. The combination of linear motion of the radar andthe rotation of the knife-beam antenna can be exploited to build up a two-dimensional mapof the surface, which enables better understanding of wave processes and to study theirstructure and temporal dynamics using repeated observations.
p. 643-666
Received: 6 April 2006 / Accepted: 16 May 2006 / Published: 24 June 2006
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| Download PDF Full-text (995 KB) Abstract: In this review we discuss the advances in use of GaN and ZnO-based solid-statesensors for gas sensing applications. AlGaN/GaN high electron mobility transistors(HEMTs) show a strong dependence of source/drain current on the piezoelectricpolarization -induced two dimensional electron gas (2DEG). Furthermore, spontaneous andpiezoelectric polarization induced surface and interface charges can be used to develop verysensitive but robust sensors for the detection of gases. Pt-gated GaN Schottky diodes and Sc2 O3 /AlGaN/GaN metal-oxide semiconductor diodes also show large change in forwardcurrents upon exposure to H2 containing ambients. Of particular interest are methods fordetecting ethylene (C2 H4 ), which offers problems because of its strong double bonds andhence the difficulty in dissociating it at modest temperatures. ZnO nanorods offer largesurface area, are bio-safe and offer excellent gas sensing characteristics.
(This article belongs to the Special Issue
Gas Sensors )
p. 667-679
Lingyan Wang , Nancy N. Kariuki , Mark Schadt , Derrick Mott , Jin Luo , Chuan-Jian Zhong , Xiajing Shi , Chen Zhang , Weibing Hao , Susan Lu , Nam Kim and Jian-Q. Wang
Received: 17 April 2006 / Accepted: 13 June 2006 / Published: 22 June 2006
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| Download PDF Full-text (181 KB) Abstract: This paper describes the results of a study of a few design parameters influencingthe performance of sensor arrays constructed from nanostructured thin films andinterdigitated microelectrodes (IMEs). The nanostructured thin films on the IME deviceswere prepared from nonanedithiol (NDT) and mercaptoundecanoic acid (MUA) linkedassemblies of 2-nm sized gold nanoparticles. The sensor array data in response to volatileorganic compounds were collected and analyzed using fractional factorial experimentaldesign and analysis of variance for understanding effects of the design parameters on thesensitivity. While the smaller value for the microelectrode space, width, and lengthgenerally led to higher response sensitivity, a strong dependence on the nature of thenanostructured thin films was found. The microelectrode space was the most importantdesign parameter for NDT-based thin films. However, the microelectrode space, width, andlength were found to play almost equally important roles for MUA-based thin films. Theprincipal component analysis results for classification performances of the arrays consistingof a set of thin films have demonstrated the possibility of optimizing sensor arrays byappropriate selections of microelectrode parameters and nanostructured sensing films.
p. 680-687
Received: 15 March 2006 / Accepted: 22 June 2006 / Published: 23 June 2006
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| Download PDF Full-text (197 KB) Abstract: We have recently presented an integrated silicon-glass opto-chemical sensor forlab-on-chip applications, based on porous silicon and anodic bonding technologies. In thiswork, we have optically characterized the sensor response on exposure to vapors of severalorganic compounds by means of reflectivity measurements. The interaction between theporous silicon, which acts as transducer layer, and the organic vapors fluxed into the glasssealed microchamber, is preserved by the fabrication process, resulting in optical pathincrease, due to the capillary condensation of the vapors into the pores. Using theBruggemann theory, we have calculated the filled pores volume for each substance. Thesensor dynamic has been described by time-resolved measurements: due to the analysischamber miniaturization, the response time is only of 2 s. All these results have beencompared with data acquired on the same PSi structure before the anodic bonding process.
p. 688-696
Received: 17 February 2006 / Accepted: 22 June 2006 / Published: 27 June 2006
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| Download PDF Full-text (215 KB) Abstract: The Martian regolith is exposed to solar irradiation in the near-UV (200-390 nm).Basalt is one of the main components of the dust on Mars surface. The near-UV irradiationof basalt dust on Mars is simulated experimentally in order to determine the transmittance asa function of the mass and thickness of the dust. This data can serve to quantify theabsorption of dust deposited on sensors aiming to measure the UV intensity on Marssurface. The minimum thickness of the dust that corresponds to near-zero-transmittance inthe near-UV is measured. Hypothetical Martian microorganisms living on the dusty regolithat deeper layers would be preserved from the damaging solar UV irradiation.
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