The Experts below are selected from a list of 168 Experts worldwide ranked by ideXlab platform

E Pagliarini - One of the best experts on this subject based on the ideXlab platform.

  • design and setting up of a water vapour pressure Capacitance Manometer for measurement of water activity
    Journal of Food Engineering, 1998
    Co-Authors: Bruno Zanoni, C Peri, G Giovanelli, E Pagliarini
    Abstract:

    Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure Capacitance Manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.

Bruno Zanoni - One of the best experts on this subject based on the ideXlab platform.

  • design and setting up of a water vapour pressure Capacitance Manometer for measurement of water activity
    Journal of Food Engineering, 1998
    Co-Authors: Bruno Zanoni, C Peri, G Giovanelli, E Pagliarini
    Abstract:

    Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure Capacitance Manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.

Shingo Ichimura - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Temperature and Humidity on Partial Pressure Measurement using Dual Pressure Gauges
    Journal of The Vacuum Society of Japan, 2020
    Co-Authors: Atsushi Suzuki, Akira Kurokawa, Hidehiko Nonaka, Shingo Ichimura
    Abstract:

    Taking into account the utilization of partial pressure measurement under various temperatures and humidity, their influence on this measurement with a Capacitance Manometer and a quartz friction pressure gauge (Q-gauge) is studied. With increasing humidity, a Q-gauge pressure reading, calibrated by air gas, decreases as well as when the hydrogen leakage is detected. To avoid this error by humidity for the hydrogen sensing, we tried to compensate influence of humidity using a humidity coefficient which is calculated from the humidity dependence of the Q-gauge pressure reading at constant temperature, and suppressed to one-fifth of the fluctuation of the Q-gauge pressure reading background due to humidity change. Regarding to influence of temperature on the Q-gauge pressure reading, it is calibrated by the temperature dependence at low humidity. Finally, influences of temperature and humidity on the hydrogen sensing can be reduced by the calculation below the reading by 0.6 at.% of hydrogen gas.

  • Hydrogen Gas Sensing using Two Type of Pressure Gauges
    Journal of The Vacuum Society of Japan, 2005
    Co-Authors: Atsushi Suzuki, Akira Kurokawa, Hidehiko Nonaka, Shingo Ichimura
    Abstract:

    For safety hydrogen sensing, the pressure measurement with a Capacitance Manometer and a quartz friction pressure gauge (Q-gauge) were investigated. Q-gauge pressure reading decreases when hydrogen gas is introduced into air supplied from atmosphere without any change of pressure measured by a Capacitance Manometer. This result indicates that the present pressure measurement using two pressure gauges is possible to detect the hydrogen leakage into air. In addition, a decrease of Q-gauge pressure reading correlates with a flow rate of the hydrogen gas, and increases with hydrogen concentration in air. Then it was shown that the low detection limit of hydrogen concentration is below 1%. Response time for hydrogen introduction is faster than 30 seconds, which meets the requirements for the hydrogen gas leak sensor. As above, the present safe pressure measurement using a Capacitance Manometer and a Q-gauge is satisfactorily useful for the hydrogen gas leak sensing.

  • Ozone Concentration Measurement of O2-O3 Binary Gas with Two Types of Pressure Gauges
    Shinku, 2004
    Co-Authors: Akira Kurokawa, Hisao Hojyo, Sonoko Tsukahara, Takichi Kobayashi, Shingo Ichimura
    Abstract:

    A concentration measuring method for a binary gas system, which was based on the viscosity measurement, was investigated. The method utilizes two types of pressure gauges, a Capacitance Manometer which depends just on pressure and a quartz friction pressure gauge which depends on both viscosity and pressure of a binary gas. The concentration of the binary gas can be estimated from the viscosity because the viscosity is given as a function of concentration of the binary gas. Firstly we applied the pressures-observing system to evaluate concentration of ozone in an O3/O2gas mixture. The results indicated that this method allows a concentration measurement of ozone with an accuracy ofΔ Cozone = 0.2 vol%, near atmospheric pressure. Secondly, we used an impedance measurement system of a quartz oscillator and we estimated the accuracy at Δ Cozone=0.05 vol%.

  • Partial-pressure measurement of atmospheric-pressure binary gas using two pressure gauges
    Vacuum, 2004
    Co-Authors: Akira Kurokawa, Kenji Odaka, Shingo Ichimura
    Abstract:

    Abstract We investigated a new method to measure the partial pressure of a binary gas system at near-atmospheric pressure conditions. The method utilizes two types of vacuum gauges, a Capacitance Manometer and a quartz friction pressure gauge. The partial pressure of the binary gas can be estimated by measuring the impedance change with a quartz friction pressure gauge, which depends on both viscosity and total pressure of a binary gas, and considering the total pressure change as measured by a Capacitance Manometer. We applied this method to measure the partial pressure of ozone in an ozone–oxygen gas mixture. The results suggested that the new method allows a partial-pressure measurement of ozone with an accuracy of Δ p =0.2 kPa , close to atmospheric pressure. The advantages of the new method include compact size, high safety standards when measuring highly reactive gases, and the allowance for in-line monitoring.

  • Measurement of Binary Gas Concentration with Quartz Gauge
    Shinku, 2001
    Co-Authors: Akira Kurokawa, Shingo Ichimura, Hidehiko Nonaka, Hisao Hojyo
    Abstract:

    To measure concentration of binary mixture gas we developed a new method that uses a Quartz gauge together with a Capacitance Manometer. Because a Quartz gauge's sensor is sensitive to both gas viscosity and gas pressure while a Capacitance Manometer is just sensitive to gas pressure, the viscosity of the gas can be estimated from pressure indication from both the gauges. If the gas is binary mixture gas and the viscosity of the gas changes monotonically with the concentration, the pressure deviation will give the concentration of binary mixture gas. This method has several merits. One is that we can apply to explosive gases because the sensors do not have any source to ignite such as a heated wire, an energetic light, and an electron source. The other is that because of no source to decompose the gas, this method does not change the concentration of the sample gas after the measurement. Then it is not necessary to discard the sampled gas, and consequently the effective amount of the sample is negligible.

C Peri - One of the best experts on this subject based on the ideXlab platform.

  • design and setting up of a water vapour pressure Capacitance Manometer for measurement of water activity
    Journal of Food Engineering, 1998
    Co-Authors: Bruno Zanoni, C Peri, G Giovanelli, E Pagliarini
    Abstract:

    Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure Capacitance Manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.

G Giovanelli - One of the best experts on this subject based on the ideXlab platform.

  • design and setting up of a water vapour pressure Capacitance Manometer for measurement of water activity
    Journal of Food Engineering, 1998
    Co-Authors: Bruno Zanoni, C Peri, G Giovanelli, E Pagliarini
    Abstract:

    Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure Capacitance Manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.