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  • 1990-1994  (7)
  • Electrogastrography  (4)
  • Chemical Engineering  (2)
  • Electrogastrogram  (2)
Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 28 (1990), S. 531-536 
    ISSN: 1741-0444
    Schlagwort(e): Autoregressive moving average modelling ; Electrogastrography ; Gastric motility ; Gastric slow wave ; Spectral analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The recording of the human, gastric myoelectrical activity, by means of cutaneous electrodes is called electrogastrography (EGG). It provides a noninvasive method of studying electrogastric behaviour. The normal frequency of the gastric signal is about 0·05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to gastric motility disorders. Thus, spectral analysis, especially online spectral analysis, can serve as a valuable tool for practical purposes. The paper presents a new method of the adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average (ARMA) modelling. It is based on an adaptive ARMA filter and provides both time and frequency information of the signal. Its performance is investigated in comparison with the conventional FFT-based periodogram method. Its properties in tracking time-varying instantaneous frequencies are shown. Its applications to the running spectral analysis of cutaneous electrogastric signals are presented. The proposed adaptive ARMA spectral analysis method is easy to implement and is efficient in computations. The results presented in the paper show that this new method provides a better performance and is very useful for the online monitoring of cutaneous electrogastric signals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 207-214 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The interactive effects of heat and mass transfer in evaporation of binary mixtures flowing as falling films on vertical surfaces was investigated. Evaporative heat-transfer coefficients were measured for aqueous mixtures of ethylene and propylene glycol, with boiling ranges up to 55°C. Tests were carried out at atmospheric pressure with heat fluxes ranging from 3,000 to 25,000 W/m2, and film Reynolds numbers ranging from 300 to 3,000. Results indicated that the heat-transfer coefficient for mixtures depends weakly on wall superheat and film Reynolds number, but strongly depends on mixture composition. Analysis of the results indicates that mass-transfer resistance in the liquid film causes significant elevation of the interface temperature, causing a reduction of the effective temperature driving force. A semiempirical model for correlation of the interactive heat-and mass-transfer phenomena is proposed.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 29 (1991), S. 339-350 
    ISSN: 1741-0444
    Schlagwort(e): Bio-potential ; Electrogastrography ; Gastric motility ; Myoelectrical activity ; Signal analysis ; Slow wave ; Stomach
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Electrogastrography (EGG), the cutaneous recording of the myoelectrical activity of the stomach using surface electrodes, is attractive due to its non-invasiveness and its correlation with gastric motility. Since the first measurement of the EGG, a great deal of research effort has been expended on investigating its relationship with specific activities of the stomach in question. In this review, we discuss how to measure the EGG, what information is available in the EGG, how to extract useful information from the EGG and the prospective applications of the EGG. After a brief historic evolution of the EGG, we first discuss the measurement of the EGG, the importance of localisation of the stomach and the characteristics of the EGG. The most commonly used EGG data-analysis methods, both power spectral analysis and waveform analysis, are then outlined. Some of prospective applications of the EGG in clinical diagnosis and medical research are described, mainly concerning the correlation between EGG amplitude and gastric motility and that between EGG rhythmic variations and motility disorders. Specifically, we present studies on pre- and postprandial EGGs, observation of the propagation direction of the gastric slow wave and gastric electrical dysrhythmias and their correlation with gastric motility.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 29 (1991), S. 351-357 
    ISSN: 1741-0444
    Schlagwort(e): Bioelectric potential ; Electrogastrogram ; Electromyography ; Gastric motility ; Slow wave ; Stomach
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The gastric electric activity paces the contractions of the stomach and can be measured noninvasively using surface electrodes placed on the abdomen. In this paper, response of the gastric electric activity to water and a solid meal was investigated using surface electrodes. Applying an improved recording technique, power spectral analysis and statistical analysis methods, the gastric electric activity in preprandial, postwater and postprandial states was measured and analysed from ten healthy volunteers. To more convincingly show the effect of water and the solid meal on the gastric slow wave and gastric motility, simultaneous recordings of the cutaneous EGG and manometric activities in the stomach were performed in three gastroparetic patients. It was found that water does not induce contractions of the stomach, but the gastric slow wave amplitude increases (p〈0·05) and frequency decreases (p〈0·05). The solid meal results in an increase in both the amplitude (p〈0·01) and the frequency (p〈0·02) of the gastric slow wave. It appears that the postprandial EGG amplitude increases because of a combination of stomach contractions and gastric distension bringing the stomach closer to the recording electrodes. The slow wave frequency, however, correlates well with stomach contractions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 30 (1992), S. 564-567 
    ISSN: 1741-0444
    Schlagwort(e): Electrogastrography ; Milk ; Myoelectrical activity ; Slow wave ; Spectrum analysis ; Stomach
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 31 (1993), S. 60-67 
    ISSN: 1741-0444
    Schlagwort(e): Electrogastrogram ; Electrogastrography ; Gastric motility ; Intestinal motility ; Myoelectrical activity ; Spectral analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 14 (1993), S. 395-401 
    ISSN: 0272-8397
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: Toughened and untoughened epoxy and BMI carbon fiber reinforced composites were evaluated in terms of their matrix chemical stability in galvanic reactions between metals and composites. It has been known that the presence of moisture and salts and contact between unprotected metals and BMI carbon fiber composition constitute prerequisite conditions for composite degradation. This study has further demonstarated that these conditions were necessary, but not sufficient. It was found that the OH species generated by galvanic reactions had to be concentrated in localized spots to induce composite degradation at a significant rate. A mechanism was proposed to elucidate how degradation took place under those necessary conditions with the aid of localized aggregation of the OH- species. Additionally, thoughening of BMI composite matrix resins resulted in poorer resistance to degradation by galvanic reactions. On the other hand, none of the eposy composites (toughened or untoughened) exhibited any degradation due to galvanic reactions at room temperature, nor did they degrade in a concentrated caustic NaOH solution (pH = 14,82°C) that simulated a highly accelerated galvanie reaction.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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