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Abstract  

Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.

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Humidity controlled thermal analysis

The effect of humidity on thermal decomposition of zinc acetylacetonate monohydrate

Journal of Thermal Analysis and Calorimetry
Authors: T Arii and A Kishi

Abstract  

The low temperature formation of crystalline zinc oxide via thermal decomposition of zinc acetylacetonate monohydrate C10H14O4ZnH2O was studied by humidity controlled thermal analysis. The thermal decomposition was investigated by sample-controlled thermogravimetry (SCTG), thermogravimety combined with evolved gas analysis by mass spectrometry (TG-MS) and simultaneous differential scanning calorimetry and X-ray diffractometry (XRD-DSC). Decomposition of C10H14O4ZnH2O in dry gas by linear heating began with dehydration around 60C, followed by sublimation and decomposition above 100C. SCTG was useful because the high-temperature parallel decompositions were inhibited. The decomposition changed with water vapor in the atmosphere. Formation of ZnO was promoted by increasing water vapor and could be synthesized at temperatures below 100C. XRD-DSC equipped with a humidity generator revealed that C10H14O4ZnH2O decomposed directly to the crystalline ZnO by reacting with water vapor.

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Abstract  

Part I of the short survey covers definitions of air humidity and the respective measuring methods such as hygrometry, psychrometry, dew point measurement, LIDAR hygrometry and humidity sensors. Techniques based on property changes of matter with adsorbed moisture from air are reviewed.

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Abstract  

The use of dataloggers in food engineering is discussed in two examples. The first example describes the measurement of temperature and humidity in a bulk tank car during transport and unloading. In the case of wheat flour the relative humidity in the air raises from about 80% r.h. to values near 100% r.h. at the air compressors for pneumatical unloading start working. The second example shows the use of the datalogger in education on heat transfer. The device was fixed in an ice cream sample which was placed in a store at –25°C. The measured hardeningtime agrees well to theoretical heat transfer calculation.

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Abstract  

Growth of mould fungi is one of the main causes of deterioration of foodstuffs, building materials and textiles. A new microcalorimetric technique has been developed for the study of mould activity as a function of water activity, temperature and atmospheric composition. This paper describes the method, in particular how to measure mould activity as a function of relative humidity.

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Summary  

Heat and CO2rates are measured on M. domesticapupae as a function of age and temperature. Heats of combustion of flies, pupae, and puparia are also measured. Heat and CO2rates decrease for 3 d post-pupation and increase exponentially over 4 d prior to eclosure. Heat and CO2rates are low and increase slowly from 5 to 23C, then rapidly increase from 23 to 26C, then more slowly up to 38C where pupae are stressed. Respiratory substrate varies with age and temperature, is a mix of lipids and carbohydrates, and has an average carbon oxidation state of -0.3 at room temperature. Humidity, elevated CO2, or reduced O2did not affect pupal metabolism.

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content of wheats as a function of temperature and humidity. J. Soc. Chem. Industry 60 :44–46. Gane R. The water content of wheats as a function of temperature and humidity

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,290. Pflanzensoziologie. II. Aufl 141 142 Buxton, P. A. (1932): Terrestrial insects and the humidity of the environment. - Biol. Rev. 7 : 275

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Abstract  

Atmospheric humidity in the surroundings of A-1 atomic power station is taken off by means of an absorption equipment in order to measure natural tritium concentration in atmosphere. Atmospheric water is reduced with Mg at 580°C, and hydrogen obtained is used for catalytic hydrogenation of acetylene. Optimum conditions of ethane preparation in dependence of temperature, molar ratio of the components, flow rate and the number of hydrogenation cycles when using the new selective nickel catalyst 40-01 are reported.

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Abstract  

Effects of humidity and light conditions /fluoroscent light, sunlight and diffuse sunlight/ on the response of 2 mm thick clear polymethylmethacrylate /PMMA/ dosimeter during irradiation and during postirradiation storage were determined spectrophotometrically at 305 and 314 nm. The results showed that irradiation of dosimeters at 12–97% relative humidity did not result in any change in the response upto 2 weeks of post-irradiation storage. However, there is some decrease in the response at higher humidities />76%/ for longer storage time. Post-irradiation storage and dosimeters at constant relative humidity conditions between 35 and 97% had no effect on the response up-to 3 weeks. Post-irradiation storage at lower relative humidity /12%/ showed some decrease in the response for longer periods. The response of dosimeter is not very sensitive to short time exposure to diffuse sunlight and fluorescent light. However, a significant increase in the optical density was observed during exposure of dosimeters to direct sunlight.

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