The Experts below are selected from a list of 13533 Experts worldwide ranked by ideXlab platform

M.t.s.r. Gomes - One of the best experts on this subject based on the ideXlab platform.

  • An Electronic Nose Based on Coated Piezoelectric Quartz Crystals to Certify Ewes’ Cheese and to Discriminate between Cheese Varieties
    Sensors, 2012
    Co-Authors: Vânia F. Pais, Joao A B P Oliveira, M.t.s.r. Gomes
    Abstract:

    An electronic nose based on coated piezoelectric Quartz Crystals was used to distinguish cheese made from ewes’ milk, and to distinguish cheese varieties. Two sensors coated with Nafion and Carbowax could certify half the ewes’ cheese samples, exclude 32 cheeses made from cow’s milk and to classify half of the ewes’ cheese samples as possibly authentic. Two other sensors, coated with polyvinylpyrrolidone and triethanolamine clearly distinguished between Flamengo, Brie, Gruyere and Mozzarella cheeses. Brie cheeses were further separated according to their origin, and Mozzarella grated cheese also appeared clearly separated from non-grated Mozzarella.

  • An Electronic Nose Based on Coated Piezoelectric Quartz Crystals to Certify Ewes’ Cheese and to Discriminate between Cheese Varieties
    MDPI AG, 2012
    Co-Authors: M.t.s.r. Gomes, Joao A B P Oliveira, Vânia F. Pais
    Abstract:

    An electronic nose based on coated piezoelectric Quartz Crystals was used to distinguish cheese made from ewes’ milk, and to distinguish cheese varieties. Two sensors coated with Nafion and Carbowax could certify half the ewes’ cheese samples, exclude 32 cheeses made from cow’s milk and to classify half of the ewes’ cheese samples as possibly authentic. Two other sensors, coated with polyvinylpyrrolidone and triethanolamine clearly distinguished between Flamengo, Brie, Gruyère and Mozzarella cheeses. Brie cheeses were further separated according to their origin, and Mozzarella grated cheese also appeared clearly separated from non-grated Mozzarella

  • suitability of pzt ceramics for mass sensors versus widespread used Quartz Crystals
    Sensors and Actuators B-chemical, 2003
    Co-Authors: Marta I S Verissimo, P Q Mantas, A M R Senos, J P Oliveira, M.t.s.r. Gomes
    Abstract:

    Abstract Two piezoelectric materials, Quartz and ceramic (PZT), were evaluated as mass sensors. Quartz Crystals (polished and unpolished) and one ceramic (Nb–Mn–PZT) were used to detect and quantify fructose in aqueous solutions and s -butylamine in vapour. The frequencies at minimum impedance (fn), maximum impedance (fm), series resonance frequency (fs) and parallel resonance frequency (fp) were monitored. Sensitivities of the devices to the chemical compounds are compared and related to the observed changes of the electrical parameters of the equivalent circuit. Roughness of the surface of the discs (ceramic and Quartz Crystals) and electrodes were measured and their influence in the observed frequency responses discussed.

Isao Karube - One of the best experts on this subject based on the ideXlab platform.

  • development of an odorant sensor using polymer coated Quartz Crystals modified with unusual lipids
    Biosensors and Bioelectronics, 1998
    Co-Authors: Kazuyoshi Yano, Uwe T Bornscheuer, Rolf D Schmid, Hiroshi Yoshitake, Kazunori Ikebukuro, Yuzo Masuda, Isao Karube
    Abstract:

    Abstract Ten MHz AT-cut Quartz Crystals were modified with a number of polymers and lipids to develop highly sensitive odorant sensors. Among the polymers tested, nylon exhibited the most stable sensor response. After optimization of the vapor flow rate, frequency shifts in response to alcohols were measured. A nylon-coated crystal modified with phosphatidylcholine exhibited greater frequency shifts compared with those obtained from the crystal modified with phosphatidylcholine only. Enhanced frequency shifts in response to alcohols were observed when nylon-coated Quartz Crystals were modified with three unusual artificial lipids containing α-branched acyl chains. Moreover, these sensors were shown to have sensitivity of the same order as the human sense of smell, as measured using standard odorants for olfactometry in Japan.

  • development of a chemical vapor sensor using piezoelectric Quartz Crystals with coated unusual lipids
    Analytica Chimica Acta, 1997
    Co-Authors: Kazuyoshi Yano, Uwe T Bornscheuer, Rolf D Schmid, Hiroshi Yoshitake, Kazunori Ikebukuro, Yuzo Masuda, Kenji Yokoyama, Isao Karube
    Abstract:

    Abstract Piezoelectric Quartz crystal sensors were developed using lipids with various properties for highly sensitive detection of chemical vapors. Lipids with varying lengths of alkyl chains were coated onto 10 MHz AT-cut Quartz crystal resonators and the response of these modified Crystals to chemical vapors were measured. It was shown that hydrophilic compounds, such as ethanol and methanol, could be recognized efficiently by lipids having shorter alkyl chains, whereas lipids with longer alkyl chains showed affinity to more hydrophobic vapors, such as toluene, hexane and cyclohexane. Frequency changes caused by adsorption of alcohols could be enhanced when cholesterol was co-immobilized in the lipid layer. To confirm the assumption that the sensor-response might be affected by the properties of lipids derived from acyl chains, we have examined the effects of two types of newly synthesized unusual lipids on sensor response. When lipids having one triple bond each at different positions on their alkyl chains were coated onto Quartz Crystals separately, lower responses were observed compared to responses obtained for a sensor with immobilized, saturated phosphatidylcholine. Lipids containing α-branched acyl chains, however, showed good affinity for organic vapors, and sensor responses improved 4–5-fold. Moreover, these sensors were shown to have sensitivity of the same order as the humans' sense of smell (10 −5 –10 −6 w/w in liquid paraffin) when measured using standard odorants (isovaleric acid, skatole, etc.) for an olfactometry established in Japan.

  • a novel method of immobilizing antibodies on a Quartz crystal microbalance using plasma polymerized films for immunosensors
    Analytical Chemistry, 1996
    Co-Authors: Keijiro Nakanishi, Hitoshi Muguruma, Isao Karube
    Abstract:

    A novel method of immobilizing antibodies on Quartz Crystals for use in immunosensors was developed using an ethylenediamine plasma-polymerized film matrix. The films formed on the Quartz Crystals are extremely thin and homogeneous, and they incorporate amino groups. Sensors produced using this method are more reproducible from sample to sample and exhibit lower noise and higher sensitivity than sensors made using conventional immobilization methods, e.g., via polyethylenimine and (γ-aminopropyl)trimethoxysilane. This is, to our knowledge, the first reported application of plasma-polymerized films to Quartz crystal microbalance immunosensors. Results on orientation-controlled immobilization of antibodies, reusability and calibration tests are also presented.

Lahsen Assoufid - One of the best experts on this subject based on the ideXlab platform.

  • correct interpretation of diffraction properties of Quartz Crystals for x ray optics applications corrigendum
    Journal of Applied Crystallography, 2018
    Co-Authors: Xianrong Huang, T Gog, Jungho Kim, Elina Kasman, D Casa, Michael Wieczorek, Marcelo Goncalves Honnicke, Ayman Said, Lahsen Assoufid
    Abstract:

    Errors about left-handed (laevorotatory) Quartz and right-handed (dextro­rotatory) Quartz in the paper by Huang, Gog, Kim, Kasman, Said, Casa, Wieczorek, Honnicke & Assoufid [J. Appl. Cryst. (2016), 51, 140–147] are corrected.

  • correct interpretation of diffraction properties of Quartz Crystals for x ray optics applications
    Journal of Applied Crystallography, 2018
    Co-Authors: Xianrong Huang, T Gog, Jungho Kim, Elina Kasman, A H Said, D Casa, Michael Wieczorek, Marcelo Goncalves Honnicke, Lahsen Assoufid
    Abstract:

    Quartz has hundreds of strong Bragg reflections that may offer a great number of choices for making fixed-angle X-ray analyzers and polarizers at virtually any hard X-ray energies with selectable resolution. However, Quartz Crystals, unlike silicon and germanium, are chiral and may thus appear in two different forms of handedness that are mirror images. Furthermore, because of the threefold rotational symmetry along the c axis, the {h1h2h3L} and {h2h1h3L} Bragg reflections may have quite different Darwin bandwidth, reflectivity and angular acceptance, although they have the same Bragg angle. The design of X-ray optics from Quartz Crystals therefore requires unambiguous determination of the orientation, handedness and polarity of the Crystals. The Laue method and single-axis diffraction technique can provide such information, but the variety of conventions used in the literature to describe Quartz structures has caused widespread confusion. The current studies give detailed guidelines for design and fabrication of Quartz X-ray optics, with special emphasis on the correct interpretation of Laue patterns in terms of the crystallography and diffraction properties of Quartz. Meanwhile, the Quartz Crystals examined were confirmed by X-ray topography to have acceptably low densities of dislocations and other defects, which is the foundation for developing high-resolution Quartz-based X-ray optics.

Gert Nolze - One of the best experts on this subject based on the ideXlab platform.

Jun Wang - One of the best experts on this subject based on the ideXlab platform.

  • a study of the micro machining process on Quartz Crystals using an abrasive slurry jet
    Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2015
    Co-Authors: H Qi, Jun Wang
    Abstract:

    An investigation of the micro-channelling process on a Quartz crystal using an abrasive slurry jet is presented. An experimental study is conducted first to understand the material removal process, surface quality as well as the effect of process parameters on the channelling performance, namely the material removal rate, channel depth, top channel width and channel wall inclination angle. It is found that a good micro-channel top edge appearance and bottom surface finish can be produced on Quartz crystal by employing smaller particles with a relatively small jet impact angle, but at the sacrifice of material removal rate. Predictive models for material removal rate and micro-channel depth are then developed using a combination of the dimensional analysis method and the particle impact erosion theories, where the squeeze film effect on the impact erosion is considered. The models are verified experimentally and it is found that the model predictions are in good agreement with the corresponding experimenta...

  • a study of the micro machining process on Quartz Crystals using an abrasive slurry jet
    Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2015
    Co-Authors: Jing Ming Fan, Jun Wang
    Abstract:

    An investigation of the micro-channelling process on a Quartz crystal using an abrasive slurry jet is presented. An experimental study is conducted first to understand the material removal process,...

  • impact erosion of Quartz Crystals by micro particles in abrasive waterjet micro machining
    Advanced Materials Research, 2013
    Co-Authors: H Qi, Jun Wang
    Abstract:

    Abrasive waterjet (AWJ) micro-machining is a precision processing technology with some distinct advantages. To understand the machining process, the erosion mechanism is presented and discussed when micro-particle impacting on a Quartz crystal specimen. It is found that three types of impressions are formed which are craters, micro-dents and scratches. Small-scale craters including crashed zones and radial cracks are associated with plastic flow and subsurface micro-cracks that decrease the material strength, but cause little material removal, while large-scale craters including conchoidal fractures caused by the propagation of lateral cracks dominate the volume change of the specimen. Micro-dents are produced by the impact of particles possessing small kinetic energies, and scratches are generated by particle sliding or rolling over the target surface and make a negligible contribution to material removal. The crater volume generated by the impact of individual particle is then discussed with respect to particle impacting velocity and impact angle. It shows that an increase in particle impact angle or particle velocity increases the crater volume due to the increased conchoidal fractures during the impact process.

  • an experimental study of the abrasive water jet micro machining process for Quartz Crystals
    Advanced Materials Research, 2012
    Co-Authors: Jing Ming Fan, Jun Wang
    Abstract:

    An experimental study of the machining process for micro-channels on a brittle Quartz crystal material by an abrasive slurry jet (ASJ) is presented. A statistical experiment design considering the major process variables is conducted, and the machined surface morphology and channelling performance are analysed to understand the micro-machining process. It is found that a good channel top edge appearance and bottom surface quality without wavy patterns can be achieved by employing relatively small particles at shallow jet impact angles. The major channel performance measures, i.e. material removal rate (MRR) and channel depth, are then discussed with respect to the process parameters. It shows that with a proper control of the process variables, the abrasive water jet (AWJ) technology can be used for the micro-machining of brittle materials with high quality and productivity.

  • micro grooving on Quartz Crystals by an abrasive air jet
    Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2011
    Co-Authors: Jun Wang, Alireza Moridi, P Mathew
    Abstract:

    An investigation of the micro-grooving performance of abrasive air jet (AAJ) on Quartz Crystals is presented and discussed. An experimental study was carried out first to understand the effect of process parameters on the major grooving performance measures such as groove depth, groove width, kerf taper, and surface roughness. Plausible trends for these grooving performance measures with respect to the various process variables, such as air pressure, nozzle traverse speed, jet impact angle, and abrasive mass flowrate, are discussed. It is found that AAJ is an effective technology for micromachining of Quartz Crystals and the grooving performance can be improved or optimized by selecting the process parameters properly. Predictive models are then developed for quantitatively estimating the micro-grooving performance. The models are finally verified by an experiment. It shows that the model predictions are in good agreement with the experimental results under the corresponding conditions.