Removal of gas-phase benzene in an immobilized photocatalytic reactor

The photocatalytic degradation of gas-phase benzene was studied in an immobilized – annular tube reactor using titanium dioxide as the photocatalyst. The main and interaction effects due to the influence of essential process parameters such as catalyst load (5 to 20 g·m–2), benzene concentration (0.2 – 3.1 g·m–3) and flow rate (0.2 to 1 l·min–1 corresponding to residence times of 14 s and 70 s respectively) on the removal of benzene were investigated, by carrying out experiments that were designed to express statistical significance. The main effects plot and Pareto plot provided good insight into the effect of different parameters on the removal of gas-phase benzene. A new, statistical measurement suggests that low gas–phase benzene concentration is more important for maintaining high removal efficiencies (96 %) in the photocatalytic reactor than both catalyst load and flow rate.

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An insight into the gas-phase inhibition mechanism of polymers by addition of triphenyl phosphate flame retardant

10.1063/5.0033887 ◽

2020 ◽

Author(s):

S. A. Trubachev ◽

O. P. Korobeinichev ◽

S. A. Kostritsa ◽

V. D. Kobtsev ◽

A. A. Paletsky ◽

...

Keyword(s):

Flame Retardant ◽

Gas Phase ◽

Inhibition Mechanism ◽

Triphenyl Phosphate ◽

Insight Into

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Measurement of Flow Rate of Droplets and Liquid Film in Venturi Scrubber

Volume 4: Computational Fluid Dynamics (CFD) and Coupled Codes; Decontamination and Decommissioning, Radiation Protection, Shielding, and Waste Management; Workforce Development, Nuclear Education and Public Acceptance; Mitigation Strategies for Beyond Design Basis Events; Risk Management ◽

10.1115/icone24-60641 ◽

2016 ◽

Cited By ~ 1

Author(s):

Yasuhiro Nakao ◽

Naoki Horiguchi ◽

Hiroyuki Yoshida ◽

Tetsuya Kanagawa ◽

Akiko Kaneko ◽

...

Keyword(s):

Film Thickness ◽

Liquid Film ◽

Gas Phase ◽

Flow Rate ◽

Interfacial Area ◽

Decontamination Factor ◽

Liquid Film Thickness ◽

Phase Flow ◽

Radioactive Materials ◽

Venturi Scrubber

As one of filtered venting systems which should be installed in light water reactors from viewpoint of protecting a containment vessel and suppressing the diffusion of radioactive materials, there is a system composed of venturi scrubbers. The radioactive materials in the contaminated gas are collected into liquid. By dispersed flow formed in the venturi scrubber, large interfacial area between liquid and gas was obtained, and large decontamination factor is realized. In evaluation for the decontamination performance of the venturi scrubber, interface of droplets and liquid film are important. However, there is a little knowledge about the interfacial area in the venturi scrubber for filtered venting. In this study, to obtain the interfacial area data, amount of the droplets and the liquid film in the venturi scrubber is evaluated by visualizing observation and sampling the liquid film at the outlet of the venturi scrubber. In the venturi scrubber, a pressure drop occurs in the throat part by the inflow of air from the compressor. Water flows from the tank by a pressure difference between a suctioned hole with head pressure and a throat part. An annular spray flow is then formed in the venturi scrubber. Therefore, the liquid flow rate changes according to the gas phase flow rate. To discharge separately the droplets and the liquid film, a rectangular separator is installed at the venturi scrubber outlet. The superficial gas phase flow rate is 25.2–292.3 m/s in the throat. As a result, the liquid film and the droplets through the wall were confirmed to be discharged separately by the separator. The ratio of the liquid film to the total amount of liquid is 80 to 95% and that of the droplets was estimated as 5 to 20%. However, the change of the liquid film thickness caused by the increase of gas phase flow rates was observed. When the liquid film thickness is large, it is possible that some liquid film flowing into the droplet side.

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Theoretical insight into the substituent effects on the antioxidant properties of 8-hydroxyquinoline derivatives in gas phase and in polar solvents

Canadian Journal of Chemistry ◽

10.1139/cjc-2017-0457 ◽

2018 ◽

Vol 96 (5) ◽

pp. 453-458

Author(s):

Anes El-Hadj Saïd ◽

Sidi Mohamed Mekelleche ◽

Taki-Eddine Ahmed Ardjani

Keyword(s):

Electron Transfer ◽

Gas Phase ◽

Antioxidant Properties ◽

Substituent Effects ◽

Hydrogen Atom Transfer ◽

Polar Solvents ◽

Antioxidant Power ◽

Theoretical Insight ◽

Insight Into

The objective of this work is to perform a theoretical analysis of the antioxidant properties of a series of 8-hydroxyquinolines (8-HQs) to rationalize the available experimental results and to design new potent 8-HQ derivatives. The study was carried out in gas phase and in methanol at the DFT/B3LYP/ 6-311++G(d,p) computational level. The formation of stable ArO• radicals is discussed on the basis of different mechanisms, namely, hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and single proton loss electron transfer (SPLET). The obtained results show that the HAT mechanism is, thermodynamically, more favoured in gas phase, whereas the SPLET pathway is more favoured in polar solvents. The calculated thermochemical descriptors allow classification of the antioxidant power of the studied compounds.

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Temperature and Time of Development of the Two Sexes in Drosophila

Journal of Experimental Biology ◽

10.1242/jeb.4.2.186 ◽

1926 ◽

Vol 4 (2) ◽

pp. 186-195 ◽

Cited By ~ 1

Author(s):

GERT BONNIER

Keyword(s):

Statistical Significance ◽

Pupal Stage ◽

The Other ◽

Female Development ◽

Short Intervals ◽

Influence Of Temperature On ◽

The Times ◽

The Moment ◽

First Time ◽

Insight Into

1. The time of development at 25°C. up to the moment of pupation is found to be for females and males respectively 116.62 ± 0.19 and 116.78 ± 0.20 hours. During the pupal stage the two times are 111.36 ± 0.15 and 115.46 ± 0.13 hours. 2. At 30° C. the corresponding figures are (in the same order): 99.95 ± 0.49, 103.37 ± 0.43, 78±15 ± 0.50 and 84.26 ± 0.34 hours. 3. These figures show that there is a statistical significance in the differences of the times of development of the two sexes for both the periods at 30°C. but only for the pupal stage at 25° C. It is pointed out that the fact that the longer time of male development as compared with female development at 25° C. is confined to the pupal stage, may be correlated with the other fact that the essential parts of the secondary sexual characters are developed during this stage. 4. It is shown that there is a negative correlation between the pre-pupal and pupal times of development, indicating that the longer the first time is, the shorter is, as a rule, the other time and vice versa. 5. With the aid of statistical methods it is shown that the shortening of the time of development at 30°C. as compared with the time at 25° C. is much more pronounced for the pupal than for the pre-pupal stage. 6. This last fact is discussed and it is emphasised that the ordinary methods of studying the influence of temperature on development are too rough to be of more than of a descriptive value, the only way of getting a deeper insight into the processes of development by temperature studies being the separate studies of a number of short intervals.

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Development of a Latching Valve for Micro-Chem-Lab™

10.1115/imece1999-0301 ◽

1999 ◽

Author(s):

C. Channy Wong ◽

Douglas R. Adkins ◽

Ronald P. Manginell ◽

Gregory C. Frye-Mason ◽

Peter J. Hesketh ◽

...

Keyword(s):

Power Consumption ◽

Gas Phase ◽

Flow Rate ◽

Integrated System ◽

Dead Volume ◽

Design Parameters ◽

Working Fluid ◽

Driving Voltage ◽

Magnetic Actuation ◽

Phase Detection

Abstract An integrated microsystem to detect traces of chemical agents (μChemLab™) is being developed at Sandia for counter-terrorism and nonproliferation applications. This microsystem has two modes of operation: liquid and gas phase detection. For the gas phase detection, we are integrating these critical components: a preconcentrator for sample collection, a gas chromatographic (GC) separator, a chemically selective flexural plate wave (FPW) array mass detector, and a latching valve onto a single chip. By fabricating these components onto a single integrated system (μChemLab™ on a chip), the advantages of reduced dead volume, lower power consumption, and smaller physical size can be realized. In this paper, the development of a latching valve will be presented. The key design parameters for this latching valve are: a volumetric flow rate of 1 mL/min, a maximum hold-off pressure of 40 kPa (6 psi), a relatively low power, and a fast response time. These requirements have led to the design of a magnetically actuated latching relay diaphragm valve. Magnetic actuation is chosen because it can achieve sufficient force to effectively seal against back pressure and its power consumption is relatively low. The actuation time is rapid, and valve can latch in either an open or closed state. A corrugated parylene membrane is used to separate the working fluid from internal components of the valve. Corrugations in the parylene ensure that the diaphragm presents minimum resistance to the actuator for a relativley large deflection. Two different designs and their performance of the magnetic actuation have been evaluated. The first uses a linear magnetic drive mechanism, and the second uses a relay mechanism. Preliminary results of the valve performance indicates that the required driving voltage is about 10 volts, the measured flow rate is about 50 mL/min, and it can hold off pressure of about 5 psi (34 kPa). Latest modifications of the design show excellent performance improvements.

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Experimental Verification of Impact of Sprinkled Area Length on Heat Exchange Coefficient

Advances in Materials Science and Engineering ◽

10.1155/2019/9262438 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Petr Kracik ◽

Marek Balas ◽

Martin Lisy ◽

Jiri Pospisil

Keyword(s):

Gas Phase ◽

Flow Rate ◽

Atmospheric Pressure ◽

Tube Bundle ◽

New Technology ◽

Thin Liquid Film ◽

Flow Mode ◽

Heat Exchange Coefficient ◽

Flowing Fluid ◽

The Ideal

On a sprinkled tube bundle, liquid forms a thin liquid film, and, in the case of boiling liquid, the liquid phase can be quickly and efficiently separated from the gas phase. There are several effects on the ideal flow mode and the heat transfer from the heating to the sprinkling liquid. The basic quantity is the flow rate of the sprinkling liquid, but also diameter of the tubes, pipe spacing of the tube bundle, and physical state of the sprinkling and heating fluid. Sprinkled heat exchangers are not a new technology and studies have been carried out all over the world. However, experiments (tests) have always been performed under strict laboratory conditions on one to three relatively short tubes and behaviour of the flowing fluid on a real tube bundle has not been taken into account, which is the primary aim of our research. In deriving and comparing the results among the studies, the mass flow rate based on the length of the sprinkled area is used, thus trying to adjust the different length of the heat exchanger. This paper presents results of atmospheric pressure experiments measured on two devices with different lengths of the sprinkled area but with the same number of tubes in the bundle with same pitch and surface at a temperature gradient of 15/40°C, where 15°C is the sprinkling water temperature at the outlet of the distribution pipe and 40°C is the temperature of heating water entering the bundle.

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Time Course and Magnitude of Tolerance to the Ergogenic Effect of Caffeine on the Second Ventilatory Threshold

Life ◽

10.3390/life10120343 ◽

2020 ◽

Vol 10 (12) ◽

pp. 343

Author(s):

Carlos Ruiz-Moreno ◽

Beatriz Lara ◽

Jorge Gutiérrez-Hellín ◽

Jaime González-García ◽

Juan Del Coso

Keyword(s):

Heart Rate ◽

Aerobic Exercise ◽

Body Mass ◽

Repeated Measures ◽

Time Course ◽

Ventilatory Threshold ◽

Statistical Significance ◽

Ergogenic Effect ◽

Double Blind ◽

Main Effects

Pre-exercise caffeine ingestion has been shown to increase the workload at ventilatory threshold, suggesting an ergogenic effect of this stimulant on submaximal aerobic exercise. However, the time course of tolerance to the effect of caffeine on ventilatory threshold is unknown. This study aimed to determine the evolution of tolerance to the ergogenic effect of caffeine on the ventilatory threshold. Methods: Eleven participants (age 32.3 ± 4.9 yrs, height 171 ± 8 cm, body mass 66.6 ± 13.6 kg, VO2max = 48.0 ± 3.8 mL/kg/min) took part in a longitudinal, double-blind, placebo-controlled, randomized, crossover experimental design. Each participant took part in two identical treatments: in one treatment, participants ingested a capsule containing 3 mg of caffeine per kg of body mass per day (mg/kg/day) for twenty consecutive days; in the other treatment, participants ingested a capsule filled with a placebo for the same duration and frequency. During these treatments, participants performed a maximal ramp test on a cycle ergometer three times per week and the second ventilatory threshold (VT2) was assessed by using the ventilatory equivalents for oxygen and carbon dioxide. Results: A two-way ANOVA with repeated measures (substance × time) revealed statistically significant main effects of caffeine (p < 0.01) and time (p = 0.04) on the wattage obtained at VT2, although there was no interaction (p = 0.09). In comparison to the placebo, caffeine increased the workload at VT2 on days 1, 4, 6 and 15 of ingestion (p < 0.05). The size of the ergogenic effect of caffeine over the placebo on the workload at VT2 was progressively reduced with the duration of the treatment. In addition, there were main effects of caffeine (p = 0.03) and time (p = 0.16) on VO2 obtained at VT2, with no interaction (p = 0.49). Specifically, caffeine increased oxygen uptake at VT2 on days 1 and 4 (p < 0.05), with no other caffeine–placebo differences afterwards. For heart rate obtained at VT2, there was a main effect of substance (p < 0.01), while the overall effect of time (p = 0.13) and the interaction (p = 0.22) did not reach statistical significance. Heart rate at VT2 was higher with caffeine than with the placebo on days 1 and 4 (p < 0.05). The size of the effect of caffeine on VO2 and heart at VT2 tended to decline over time. Conclusion: Pre-exercise intake of 3 mg/kg/day of caffeine for twenty days enhanced the wattage obtained at VT2 during cycling ramp tests for ~15 days of ingestion, while there was a progressive attenuation of the size of the ergogenic effect of caffeine on this performance variable. Therefore, habituation to caffeine through daily ingestion may reduce the ergogenic effect of this stimulant on aerobic exercise of submaximal intensity.

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