TY - CHAP A1 - Bukhari, Syed Faisal Ahmed A1 - Yang, Wuqiang T1 - Multi-interface level sensors and new development in monitoring and control of oil separators N2 - In the oil industry, huge saving may be made if suitable multi-interface level measurement systems are employed for effectively monitoring crude oil separators and efficient control of their operation. A number of techniques, e.g. externally mounted displacers, differential pressure transmitters and capacitance rod devices, have been developed to measure the separation process with gas, oil, water and other components. Because of the unavailability of suitable multi-interface level measurement systems, oil separators are currently operated by the trial-and-error approach. In this paper some conventional techniques, which have been used for level measurement in industry, and new development are discussed. KW - Biosensor KW - Level sensor KW - multi-interface measurement KW - electrical capacitance tomography KW - ECT Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1498 ER - TY - CHAP A1 - Chaiyboun, Ali A1 - Traute, Rüdiger A1 - Kiesewetter, Olaf A1 - Ahlers, Simon A1 - Müller, Gerhard A1 - Doll, Theodor T1 - Modular analytical multicomponent analysis in gas sensor arrays N2 - A multi-sensor system is a chemical sensor system which quantitatively and qualitatively records gases with a combination of cross-sensitive gas sensor arrays and pattern recognition software. This paper addresses the issue of data analysis for identification of gases in a gas sensor array. We introduce a software tool for gas sensor array configuration and simulation. It concerns thereby about a modular software package for the acquisition of data of different sensors. A signal evaluation algorithm referred to as matrix method was used specifically for the software tool. This matrix method computes the gas concentrations from the signals of a sensor array. The software tool was used for the simulation of an array of five sensors to determine gas concentration of CH4, NH3, H2, CO and C2H5OH. The results of the present simulated sensor array indicate that the software tool is capable of the following: (a) identify a gas independently of its concentration; (b) estimate the concentration of the gas, even if the system was not previously exposed to this concentration; (c) tell when a gas concentration exceeds a certain value. A gas sensor data base was build for the configuration of the software. With the data base one can create, generate and manage scenarios and source files for the simulation. With the gas sensor data base and the simulation software an on-line Web-based version was developed, with which the user can configure and simulate sensor arrays on-line. KW - Biosensor KW - Main sensitivity KW - cross sensitivity KW - matrix method KW - gas sensor array KW - modelling Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1358 ER - TY - CHAP A1 - Tymecki, Lukasz A1 - Glab, Stanislaw A1 - Koncki, Robert T1 - Miniaturized, planar ion-selective electrodes fabricated by means of thick-film technology N2 - Various planar technologies are employed for developing solid-state sensors having low cost, small size and high reproducibility; thin- and thick-film technologies are most suitable for such productions. Screen-printing is especially suitable due to its simplicity, low-cost, high reproducibility and efficiency in large-scale production. This technology enables the deposition of a thick layer and allows precise pattern control. Moreover, this is a highly economic technology, saving large amounts of the used inks. In the course of repetitions of the film-deposition procedure there is no waste of material due to additivity of this thick-film technology. Finally, the thick films can be easily and quickly deposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodes based on ionophores as well as crystalline ion-selective materials dedicated for potentiometric measurements are demonstrated. Analytical parameters of these sensors are comparable with those reported for conventional potentiometric electrodes. All mentioned thick-film strip electrodes have been totally fabricated in only one, fully automated thickfilm technology, without any additional manual, chemical or electrochemical steps. In all cases simple, inexpensive, commercially available materials, i.e. flexible, plastic substrates and easily cured polymer-based pastes were used. KW - Biosensor KW - Potentiometry KW - thick-film technology KW - screen-printing KW - ion-selective electrodes Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1506 ER - TY - CHAP A1 - Platen, Johannes A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Microstructured Nanostructures – nanostructuring by means of conventional photolithography and layer-expansion technique N2 - A new and simple method for nanostructuring using conventional photolithography and layer expansion or pattern-size reduction technique is presented, which can further be applied for the fabrication of different nanostructures and nano-devices. The method is based on the conversion of a photolithographically patterned metal layer to a metal-oxide mask with improved pattern-size resolution using thermal oxidation. With this technique, the pattern size can be scaled down to several nanometer dimensions. The proposed method is experimentally demonstrated by preparing nanostructures with different configurations and layouts, like circles, rectangles, trapezoids, “fluidic-channel”-, “cantilever”- and meander-type structures. KW - Biosensor KW - Nanostructuring KW - layer expansion KW - pattern-size reduction KW - self-aligned patterning Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1477 ER - TY - CHAP A1 - Baronas, Romas A1 - Ivanauskas, Feliksas A1 - Kulys, Juozas T1 - Mathematical modeling of biosensors based on an array of enzyme microreactors N2 - This paper presents a two-dimensional-in-space mathematical model of biosensors based on an array of enzyme microreactors immobilised on a single electrode. The modeling system acts under amperometric conditions. The microreactors were modeled by particles and by strips. The model is based on the diffusion equations containing a nonlinear term related to the Michaelis-Menten kinetics of the enzymatic reaction. The model involves three regions: an array of enzyme microreactors where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region, where the analyte concentration is maintained constant. Using computer simulation, the influence of the geometry of the microreactors and of the diffusion region on the biosensor response was investigated. The digital simulation was carried out using the finite difference technique. KW - Biosensor KW - Reaction-diffusion KW - modeling biosensor KW - microreactor Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1569 ER - TY - CHAP A1 - Katz, Eugenii A1 - Willner, Itamar T1 - Magneto-controlled quantized electron transfer to surface-confined redox units and metal nanoparticles N2 - Hydrophobic magnetic nanoparticles (NPs) consisting of undecanoate-capped magnetite (Fe3O4, average diameter ca. 5 nm) are used to control quantized electron transfer to surface-confined redox units and metal NPs. A two-phase system consisting of an aqueous electrolyte solution and a toluene phase that includes the suspended undecanoatecapped magnetic NPs is used to control the interfacial properties of the electrode surface. The attracted magnetic NPs form a hydrophobic layer on the electrode surface resulting in the change of the mechanisms of the surface-confined electrochemical processes. A quinone-monolayer modified Au electrode demonstrates an aqueous-type of the electrochemical process (2e-+2H+ redox mechanism) for the quinone units in the absence of the hydrophobic magnetic NPs, while the attraction of the magnetic NPs to the surface results in the stepwise single-electron transfer mechanism characteristic of a dry nonaqueous medium. Also, the attraction of the hydrophobic magnetic NPs to the Au electrode surface modified with Au NPs (ca. 1.4 nm) yields a microenvironment with a low dielectric constant that results in the single-electron quantum charging of the Au NPs. KW - Biosensor KW - Nanoparticles KW - magnetic particles KW - quantum charging KW - modified electrode Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1528 ER - TY - CHAP A1 - Spannhake, Jan A1 - Schulz, Olaf A1 - Helwig, Andreas A1 - Krenkow, Angelika A1 - Müller, Gerhard A1 - Doll, Theodor T1 - High-temperature MEMS heater platforms: long-term performance of metal and semiconductor heater materials N2 - Micromachined thermal heater platforms offer low electrical power consumption and high modulation speed, i.e. properties which are advantageous for realizing nondispersive infrared (NDIR) gas- and liquid monitoring systems. In this paper, we report on investigations on silicon-on-insulator (SOI) based infrared (IR) emitter devices heated by employing different kinds of metallic and semiconductor heater materials. Our results clearly reveal the superior high-temperature performance of semiconductor over metallic heater materials. Long-term stable emitter operation in the vicinity of 1300 K could be attained using heavily antimony-doped tin dioxide (SnO2:Sb) heater elements. KW - Biosensor KW - Hotplate KW - heater metallisation KW - high-temperature stability KW - electro-migration KW - doped silicon KW - doped metal oxide KW - antimony doped tin oxide Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1513 ER - TY - CHAP A1 - Kreutz, Christian A1 - Lörgen, Jürgen A1 - Graewe, Boris A1 - Bargon, Joachim A1 - Yoshida, Mayumi A1 - Freso, Zachary M. A1 - Frèchet, Jean M. J. T1 - High frequency quartz micro balances: a promising path to enhanced sensitivity of gravimetric sensors N2 - An array of 50 MHz quartz microbalances (QMBs) coated with a dendronized polymer was used to detect small amounts of volatile organic compounds (VOCs) in the gas phase. The results were compared to those obtained with the commonly used 10 MHz QMBs. The 50 MHz QMBs proved to be a powerful tool for the detection of VOCs in the gas phase; therefore, they represent a promising alternative to the much more delicate surface acoustic wave devices (SAWs). KW - Biosensor KW - Quartz micro balances KW - electronic noses dendronized polymers inverted mesa technology Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1445 ER - TY - CHAP A1 - Wagner, Thorsten A1 - Kohl, Claus-Dieter A1 - Fröba, Michael A1 - Tiemann, Michael T1 - Gas sensing properties of ordered mesoporous SnO2 N2 - We report on the synthesis and CO gas-sensing properties of mesoporous tin(IV) oxides (SnO2). For the synthesis cetyltrimethylammonium bromide (CTABr) was used as a structure-directing agent; the resulting SnO2 powders were applied as films to commercially available sensor substrates by drop coating. Nitrogen physisorption shows specific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verified by TEM. The film conductance was measured in dependence on the CO concentration in humid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivity at low CO concentrations and turn out to be largely insensitive towards changes in the relative humidity. We compare the materials with commercially available SnO2-based sensors. KW - Biosensor KW - Tin oxide KW - sensing properties KW - CO KW - humidity Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1422 ER - TY - CHAP A1 - Poghossian, Arshak A1 - Schumacher, Kerstin A1 - Kloock, Joachim P. A1 - Rosenkranz, Christian A1 - Schultze, Joachim W. A1 - Müller-Veggian, Mattea A1 - Schöning, Michael Josef T1 - Functional testing and characterisation of ISFETs on wafer level by means of a micro-droplet cell N2 - A wafer-level functionality testing and characterisation system for ISFETs (ionsensitive field-effect transistor) is realised by means of integration of a specifically designed capillary electrochemical micro-droplet cell into a commercial wafer prober-station. The developed system allows the identification and selection of “good” ISFETs at the earliest stage and to avoid expensive bonding, encapsulation and packaging processes for nonfunctioning ISFETs and thus, to decrease costs, which are wasted for bad dies. The developed system is also feasible for wafer-level characterisation of ISFETs in terms of sensitivity, hysteresis and response time. Additionally, the system might be also utilised for wafer-level testing of further electrochemical sensors. KW - Biosensor KW - Biosensorik KW - ISFET KW - Wafer KW - ISFET KW - wafer-level testing KW - capillary micro-droplet cell Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1259 ER -